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  • Cell & Developmental Biology  (12,126)
  • General Chemistry  (12,008)
  • Fisheries
  • Limnology
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  • 1
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    The International Collective in Support of Fishworkers (ICSF) | India
    Publication Date: 2022-02-21
    Description: Yemaya No. 63, dated May 2021, features articles from US, The Netherlands, Myanmar, Senegal, and an article on women in fisheries and human rights. The article from the US by Linda Behnken argues that a growing coalition of small-scale, community-based fishers is calling for the recognition and protection of Alaska’s invaluable coastal fisheries during COVID-19. The article from the Netherlands by Cornelie Quist looks at the challenges facing women engaged in small-scale fishing and supplying fish through retailers and how they found new ways to directly reach consumers. The conversation between Miranda Bout and Cornelie Quist focuses on how they combined new product development with the use of social media to contact their customer base during the pandemic-induced disruption of traditional marketing chains. The article by Elena Finkbeiner, Juno Fitzpatrick and Whitney Yadao-Evans looks at recent media revelations and scientific research that have brought increased attention to human-rights violations and the myriad social issues facing fisheries, but with a disproportionate focus on labour-rights violations at sea and in industrial fishing operations. The systemic inequalities combined with the effects of COVID-19 exacerbated vulnerabilities of women to health risks, food and livelihood security. The article from Senegal by Aby Dia from Lumière Synergie pour le Développement (LSD), in collaboration with WoMin African Alliance, South Africa, narrates the story of traditional women fish processors from the Bargny who have been, for more than a decade, struggling against development projects that jeopardise their environment, health and livelihoods. In order to preserve their livelihoods, women processors in Senegal have come together to oppose the Tosyali steel project. The European Network of Women in Fisheries and Aquaculture in Europe (AKTEA) urges the Office of the Commissioner for the Environment, Oceans and Fisheries to integrate gender into all aspects of European fishing policy. The Profile column looks at how Linda Behnken became a fisher in Alaska and how fishing has shaped her individuality and work. Natalie Sattler says that fishing for halibut, sablefish and salmon from the sparkling waters of the Pacific along with her children and at the same time passion for working with the Alaska Longline Fishermen’s Association and the Alaska Sustainable Fisheries Trust is an immense challenge.
    Description: Published
    Description: Refereed
    Keywords: Fishing Communities ; Women in fisheries ; Gender ; Small-scale fisheries ; Aquaculture ; Fisheries
    Repository Name: AquaDocs
    Type: Book/Monograph/Conference Proceedings
    Format: 12p.
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  • 2
    Publication Date: 2022-06-28
    Description: Las pesquerías basadas en las agregaciones reproductivas pueden amenazar a especies como los pargos que tienen conductas gregarias durante el período reproductivo. Esta nota ofrece elementos que sugieren la existencia de sitios de agregación no registrados previamente y no protegidos en el Parque Nacional Cayos de San Felipe (PNCSF), región suroccidental de Cuba. La información tradicional obtenida de pescadores locales y trabajadores del parque se corroboró con muestreos cualitativos y cuantitativos de peces de arrecifes y datos de pesquerías locales del 2014. En la época de reproducción de pargos (mayo a julio) se observaron grupos de entre 40-100 ejemplares de Lutjanus cyanopterus, Lutjanus synagris y Lutjanus jocu en los arrecifes de la zona occidental del PNCSF (camellones entre 15-30 m de profundidad cerca del borde de la plataforma). Dentro de esa área, se señalan dos sitios que parecen ser utilizados para agregaciones de predesove, por lo que requieren protección y ser estudiados. Los censos cuantitativos confirmaron que en mayo y junio la zona occidental tiene densidad alta de pargos adultos. También, el pico de captura de estas especies ocurrió en la época reproductiva. Se comprobó que las pesquerías se realizaron durante las migraciones de peces hacia el borde de la plataforma en áreas de la zona occidental del PNCSF, y que más del 60% de los individuos tuvieron gónadas maduras (antes de desovar). Esta información debe incentivar el estudio de las agregaciones de desove en esta región de Cuba, la protección de especies amenazadas y áreas de alta significación ecológica y la implementación de pesquerías sostenibles.
    Description: Fisheries based on reproductive aggregations can threaten species such as snappers that have gregarious behavior during the reproductive period. This note provides evidence to support the existence of aggregation sites, not previously registered and unprotected, in the National Park San Felipe Keys (NPSFK), southwestern region of Cuba. Traditionalinformation obtained from local fishermen and from the park staff was complemented with qualitative and quantitative fish reef censuses and local fisheries data in 2014. In the reproductive season of snappers (May to July) groups of between 40-100 specimens of Lutjanus cyanopterus, Lutja- nus synagris and Lutjanus jocu were observed in the western area of the NPSFK on the reefs (spoor and grove between 20-30 m deep close to the platform edge). Within that area two sites are indicated that can be used for prespawning aggregation, so they require protection and study. Quanti- tative censuses confirmed that in May and June the western zone has high density of adult snappers. Also, the peak of capture of these snapper species occurred in the reproduc- tive season. It was found that fisheries carried out during fish migrations to the edge of the shelf in areas of the western area of the NPSFK and more than 60% of the individuals had mature gonads (before spawning). This information should promote the study of spawning aggregations in this region of Cuba, the protection of threatened species and areas of high ecological significance and the implementation of sustainable fisheries.
    Description: Published
    Description: Refereed
    Keywords: Región suroccidental de Cuba ; Desove ; Pesquerías ; Migration routes ; Spawning ; Fisheries ; Rutas migraciones
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp.54-65
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  • 3
    Publication Date: 2022-09-14
    Description: The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recom- mendations to simplify and harmonise the ICES reference points framework representing a ma- jor change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define Blim. Around two thirds of category 1 stocks would end up as WKREF1 “Blim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “depensation” maybe more important than previously thought and should be furthered explored for ICES stocks since it has important consequences for Blim. A number of challenges and issues around defining Blim using the current guidelines were documented. Some suggestions on improvement criteria were discussed including using classifiers to define spas- modic stocks and using change point algorithms to address non-stationary productivity regimes. However, further work is need to make these approaches operational and there was no consen- sus that the WKREF1 Blim types should replace the current guidelines. WKREF1 recommended that the FMSY proxy should be based on a biological proxies and should be less than the deterministic FMSY. It was pointed out that the stochastic FMSY estimated in EqSim for example, is lower than the deterministic FMSY and that the current guidelines ensure that the FMSY should not pose a more than 5% risk to Blim. A large amount of work described in WD 1 was carried out to develop an MSE framework to consistency and robustness test a candidate refer- ence point system for North East Atlantic stocks. However, WKREF2 recommended that further work needs to be carried out to condition and test the simulation framework before the conclu- sions could be adopted by ICES and incorporated into the guidelines. A number of considerations for defining MSY related reference points were discussed including using model validation and prediction skill to ensure that ICES provide robust and credible ad- vice. There is evidence that density dependence (DD) is important in the majority of ICES stocks (68% in recruitment and 54% in growth). The correct prediction of the shape and strength of density-dependence in productivity is key to predicting future stock development and providing the best possible long-term fisheries management advice. A suggested approach to use surplus production models (SPMs) to account for DD in FMSY was suggested and discussed but there was no consensus on whether that approach was appropriate. There was consensus that the FECO approach as a means of adapting target fishing mortality to medium-term changes in productiv- ity should be included in the guidelines subject to a benchmark and ACOM approval. While WKREF1 and 2 focused mainly on Category 1 stocks ToR c) called for a “simplified and harmonised set of guidelines for estimating MSY and precautionary reference points applicable in the advice framework across various ICES stock categories.” Ideally the ICES assessment cat- egories should provide equivalent risk across all stocks. This issue was discussed but no recom- mendations emerged. There was no consensus a revised reference point framework was proposed at WKREF2. How- ever, it was agreed that it should be presented here for further discussion at ACOM and other fora. The key feature of the suggested approach is that the stock status evaluation is treated in- dependent of the Advice Rule (AR). The main feature of the system is that the biomass trigger is not linked to a stock status evaluation, it is linked to the expected biomass when fishing at the target fishing mortality, in contrast to the current ICES approach. It also entailed that FMSY would also become an upper limit of fishing mortality and that the advised fishing mortality would be set at or lower than that level. WKREF2 did not discuss what to do in situations where SSB〈 Blim or alternative forms of HCR for the advice rule. Building community understanding and con- sensus around simplified and harmonised guidelines has yet to be achieved. A further workshop WKREF3 will be required to achieve that aim. The report includes 6 recommendations for ACOM consideration.
    Description: ICES
    Description: The main objective of the workshop was to review the recommendations of WKREF1 and con- sider how these might feed into a new reference points framework and guidelines for ICES. There were a number of presentations on the wider issues of best practice for reference points, the Allee effect, density dependence and the WKIRISH approach. The starting point was to try and develop a set of simplified and harmonised guidelines based on the WKREF1 report rather than evolving the current guidelines to include the WKREF1 conclusions. A key aspect of the meeting was to allow for discussions in order to build a shared understanding of the strengths and weakness of the current framework and of the new framework emerging from WKREF1.
    Description: Published
    Description: Non Refereed
    Keywords: ICES ; Reference points ; Management advice ; Fisheries ; Fishery management reference points
    Repository Name: AquaDocs
    Type: Report
    Format: 103pp
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  • 4
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dowd, S., Chapman, M., Koehn, L., & Hoagland, P. The economic tradeoffs and ecological impacts associated with a potential mesopelagic fishery in the California Current. Ecological Applications, 32(4), (2022): e2578, https://doi.org/10.1002/eap.2578.
    Description: The ocean's mesopelagic zone (200–1000 m) remains one of the most understudied parts of the ocean despite knowledge that mesopelagic fishes are highly abundant. Apex predators from the surface waters are known to consume these fishes, constituting an important ecological interaction. Some countries have begun exploring the potential harvest of mesopelagic fishes to supply fishmeal and fish oil markets due to the high fish abundance in the mesopelagic zone compared with overfished surface waters. This study explored the economic and ecological implications of a moratorium on the harvest of mesopelagic fishes such as lanternfish off the US West Coast, one of the few areas where such resources are managed. We adapted a bioeconomic decision model to examine the tradeoffs between the values gained from a hypothetical mesopelagic fishery with the potential values lost from declines in predators of mesopelagic fishes facing a reduced prey resource. The economic rationale for a moratorium on harvesting mesopelagics was sensitive both to ecological relationships and the scale of the nonmarket values attributed to noncommercial predators. Using a California Current-based ecological simulation model, we found that most modeled predators of mesopelagic fishes increased in biomass even under high mesopelagic harvest rates, but the changes (either increases or decreases) were small, with relatively few predators responding with more than a 10% change in their biomass. While the ecological simulations implied that a commercial mesopelagic fishery might not have large biomass impacts for many species in the California Current system, there is still a need to further explore the various roles of the mesopelagic zone in the ocean.
    Description: Sally Dowd acknowledges sponsorship from the WHOI Summer Student Fellowship and the Rausser College of Natural Resources Honors Program at UC Berkeley. This project would not have been possible without the guidance provided by Kama Thieler and Carl Boettiger. Porter Hoagland acknowledges funding from the Audacious Project, a collaborative endeavor, housed at TED and the J. Seward Johnson Fund in support of the Marine Policy Center at WHOI.
    Keywords: Bioeconomic model ; Fisheries ; Mesopelagic fishes ; Moratorium ; Nonmarket value ; Predators ; Rpath ; Willingness-to-pay values
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 5
    Publication Date: 2022-05-27
    Description: Buesseler, K., Jin, D., Kourantidou, M., Levin, D., Ramakrishna, K., Renaud, P., Ausubel, J., Baltes, K., Gjerde, K., Holland, M., Kostel, K., LaCapra, V., Martin, A., Sosik, H., Thorrold, S., Tierney, T., Joyce, K., Renier, N., Taylor, E. (2022). The Ocean Twilight Zone’s Role in Climate Change. Woods Hole Oceanographic Institution, 32 pp.
    Description: The ocean twilight zone (more formally known as the mesopelagic zone) plays a fundamental role in global climate. It is the mid-ocean region roughly 100 to 1000 meters below the surface, encompassing a half-mile deep belt of water that spans more than two-thirds of our planet. The top of the ocean twilight zone only receives 1% of incident sunlight and the bottom level is void of sunlight. Life in the ocean twilight zone helps to transport billions of metric tons (gigatonnes) of carbon annually from the upper ocean into the deep sea, due in part to processes known as the biological carbon pump. Once carbon moves below roughly 1000 meters depth in the ocean, it can remain out of the atmosphere for centuries to millennia. Without the benefits of the biological carbon pump, the atmospheric CO 2 concentration would increase by approximately 200 ppm 1 which would significantly amplify the negative effects of climate change that the world is currently trying to curtail and reverse. Unfortunately, existing scientific knowledge about this vast zone of the ocean, such as how chemical elements flow through its living systems and the physical environment, is extremely limited, jeopardizing the efforts to improve climate predictions and to inform fisheries management and ocean policy development.
    Description: Funding is: The Audacious Project housed at TED
    Keywords: Climate ; Mesopelagic ; Twilight Zone ; Fisheries ; Carbon Dioxide Removal ; Ocean ; Biological Carbon Pump ; Solubility Pump ; Carbon ; Marine Snow
    Repository Name: Woods Hole Open Access Server
    Type: Other
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  • 6
    Publication Date: 2022-10-26
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kourantidou, M., Hoagland, P., Dale, A., & Bailey, M. Equitable allocations in northern fisheries: bridging the divide for Labrador Inuit. Frontiers in Marine Science, 8, (2021): 590213, https://doi.org/10.3389/fmars.2021.590213.
    Description: Canada has undertaken commitments to recognize the rights of Indigenous Peoples in fisheries through policies and agreements, including Integrated Fishery Management Plans, the Reconciliation Strategy, and Land Claim Agreements (LCAs). In addition to recognizing rights, these commitments were intended to respect geographic adjacency principles, to enhance the economic viability of Indigenous communities, and to be reflective of community dependence on marine resources. We examined the determinants of quota allocations in commercial fisheries involving Nunatsiavut, Northern Labrador, the first self-governing region for the Inuit peoples in Canada. It has been argued that current fishery allocations for Nunatsiavut Inuit have not satisfied federal commitments to recognize Indigenous rights. Indicators that measure equity in commercial allocations for the turbot or Greenland halibut (Reinhardtius hippoglossoides) and northern shrimp (Pandalus borealis) fisheries were identified and assessed. In these two cases, historical allocations continue to predominate for allocations based upon equity or other social or economic considerations. We illustrate equity-enhancing changes in the quota distribution under scenarios of different levels of inequality aversion, and we make qualitative assessments of the effects of these allocations to Nunatsiavut for socioeconomic welfare. This approach could benefit fisheries governance in Northern Labrador, where federal commitments to equity objectives continue to be endorsed but have not yet been integrated fully into quota allocations.
    Description: This research was undertaken with funding from the Canada First Research Excellence Fund through the Ocean Frontier Institute (MK and MB) and the Johnson Endowment of the Woods Hole Oceanographic Institution’s (WHOI) Marine Policy Center (PH).
    Keywords: Fisheries ; Allocations ; Equity ; Indigenous rights ; Access
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 7
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    In:  aqdchief@seafdec.org.ph | http://aquaticcommons.org/id/eprint/18569 | 2002 | 2015-11-15 16:06:30 | 18569 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Description: This paper summarizes the results of the experiments on the induced breeding and larval rearing of milkfish (Chanos chanos) during the 1979 season. Milkfish larvae could be reared successfully without the use of trochophore larvae of oysters as feed during the first few days. In order to induce the ovulation of wild adult milkfish a higher dose of human chorionic gonadotropin hormone is required.
    Keywords: Fisheries ; Chanos chanos ; ISEW ; Philippines ; marine environment ; Brood stocks ; Fish culture ; Fish larvae ; Food organisms ; Induced breeding ; Larval development ; Sex hormones
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
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    Format: 1-3
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  • 8
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20100 | 17342 | 2016-02-24 22:18:26 | 20100 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Description: An outline is given of aquaculture and fisheries in Asia, providing information of use to students whose work can influence laws, rules, policy and regulations on aquaculture and fisheries, with the view in mind to sustainable aquaculture. In this issue, the following countries are examined: China, Indonesia, and Bangladesh.
    Keywords: Aquaculture ; Fisheries ; Fishery management ; Aquaculture development ; Aquaculture regulations ; Marine aquaculture ; Freshwater aquaculture ; Fishery industry ; Asia ; Bangladesh ; China
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: 7-8
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  • 9
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20067 | 2002 | 2016-03-04 15:16:24 | 20067 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Aquaculture ; Vietnam ; Sri Lanka ; Sri Lanka ; Vietnam ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture techniques ; Brackishwater aquaculture ; Feed ; Fish culture ; Fish diseases ; Fisheries ; Fishery data ; Food organisms ; Freshwater aquaculture ; Marine aquaculture ; Marine fisheries ; Mollusc culture ; Pond culture ; Seaweed culture ; Shrimp culture
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 27
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  • 10
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20055 | 2002 | 2016-03-03 11:33:32 | 20055 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Aquaculture ; Asia ; Cambodia ; India ; Asia ; Cambodia ; India ; Myanmar ; Myanmar ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture development ; Aquaculture economics ; Aquaculture techniques ; Brackishwater aquaculture ; Catching methods ; Culture effects ; Environmental impact ; Fish culture ; Fisheries ; Fishery development ; Fishery resources ; Fishery statistics ; Freshwater aquaculture ; Marine aquaculture ; Shrimp culture ; Sustainability ; Trade
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 29
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  • 11
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26291 | 23782 | 2019-04-08 09:42:05 | 26291 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Pollution ; Indonesia ; Heavy metals ; Chemical pollution ; Pollution monitoring
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 10-19
    Format: 10
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  • 12
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26293 | 23782 | 2019-03-22 03:49:21 | 26293 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Myanmar ; Heavy metals ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 38-46
    Format: 9
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  • 13
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26259 | 2002 | 2019-03-01 05:56:06 | 26259 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: Round scad exploration by purse seine in the waters of western Philippines was conducted from April 22 to May 7, 1998 for a period of five (5) fishing days with a total catch of 7.3 tons and an average of 1.5 tons per setting. Dominant species caught were Decapterus spp. having 70.09% of the total catch, followed by Selar spp. at 12.66% and Rastrelliger spp. 10.70%. Among the Decapterus spp. caught, D. macrosoma attained the highest total catch composition by species having 68.81% followed by D. kurroides and D.russelli with 0.31% and 1.14% respectively. The round scad fishery stock was composed mainly of juvenile fish (less than 13 cm) and Age group II (13 cm to 14 cm). Few large round scad at Age group IV and V (20 cm to 28 cm) stayed at the fishery. Other fishes caught were: Auxis rochei (0.85%), A. thazard (0.12%), Caranx spp. (0.45%), Emmilichthys nitidus (0.58%), Euthynnus affinis (0.42%), Leiognathus ruconius (0.58%), Loligo sp. (0.31%), Megalaspis cordyla (0.09%), Rastrelliger spp. (10.70%), Sardinella longiceps (0.03%), Scomberoides lysan (0.24%), Selar spp. (12.66%), Sphyraena spp. (0.90%), Thunnus albacares (0.96%) and others (1.02%). Tuna and tuna like fishes such as yellowfin tuna, eastern little tuna, bullet tuna, frigate tuna and oceanic squid are distributed in the upper latitudes of the survey area. On the other hand, round scads, big-eyed scads and Indian mackerels are dominantly present in the lower latitudes of the survey area.
    Keywords: Fisheries ; Exploratory fishing ; Purse seining ; Age composition ; Catch composition ; Fishery surveys ; Carangid fisheries ; South China Sea ; Philippines ; Rastrelliger ; Decapterus
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    Format: 49-64
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  • 14
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    Training Department, Southeast Asian Fisheries Development Center | Samut Prakarn, Thailand
    In:  http://aquaticcommons.org/id/eprint/26215 | 17342 | 2019-02-08 06:25:54 | 26215 | Southeast Asian Fisheries Development Center, Training Department
    Publication Date: 2022-08-02
    Description: Presented in this paper is the status of the fishery industry in Brunei Darussalam. Specifically, it discussed the following topics: fishery management strategies, zonation scheme, licencing, the use of poisons and explosives, the minimum cod-end mesh size for trawlers, closed areas, enhancement of fishing grounds, and the enforcement activities.
    Keywords: Fisheries ; Fishery resources ; Fishery management ; Fisheries ; Ecological zonation ; Licensing ; Fish poisoning ; Catching methods ; Illegal fishing ; Explosive fishing ; Fishing gear ; Season regulations ; Fishing grounds
    Repository Name: AquaDocs
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  • 15
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26295 | 23782 | 2019-03-22 08:39:12 | 26295 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Thailand ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
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    Type: book_section
    Format: application/pdf
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    Format: 53-58
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  • 16
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26292 | 23782 | 2019-03-22 03:43:09 | 26292 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Malaysia ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
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    Format: 20-37
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  • 17
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26258 | 2002 | 2019-03-01 06:00:19 | 26258 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: An exploratory tuna longline fishing survey was conducted using the research and training vessels of the Southeast Asian Fisheries Development Center, the 1,178 GT MV SEAFDEC and the Bureau of Fisheries and Aquatic Resources, the 165 GT MV MAYA-MAYA in the South China Sea Waters, West of the Philippines from April to May, 1998. A total of 3,796 hooks was set in sixteen (16) fishing stations. There were no tuna caught during the entire survey but only minor and irrelevant species like the Pacific lancetfish, sharks and an opah species, Lampris guttatus. The important fishing and oceanographic factors during the survey and other research results on longline are described and analyzed. Additional longline studies within and near the Philippines territorial waters are also presented to substantiate the research results of the joint SEAFDEC/BFAR resource exploratory.
    Keywords: Fisheries ; Exploratory fishing ; Catch composition ; Fishery surveys ; Longlining ; Tuna fisheries ; South China Sea ; Philippines
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  • 18
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26299 | 23782 | 2019-03-27 06:00:01 | 26299 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Chemistry ; Fisheries ; Malaysia ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Biochemical analysis ; Lethal limits
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  • 19
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26300 | 23782 | 2019-03-27 05:58:36 | 26300 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Aquaculture ; Chemistry ; Fisheries ; Myanmar ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Lethal limits
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26307 | 23782 | 2019-03-27 03:35:56 | 26307 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Indonesia ; Histamines ; Biological sampling ; Fish ; Fishery products ; Quality control
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    Format: application/pdf
    Format: 116-123
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  • 21
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26303 | 23782 | 2019-03-27 05:51:15 | 26303 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Chemistry ; Fisheries ; Thailand ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Dried products ; Lethal limits
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    Format: application/pdf
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  • 22
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26309 | 23782 | 2019-03-27 03:49:31 | 26309 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Myanmar ; Histamines ; Biological sampling ; Biochemical analysis ; Fish ; Fishery products
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    Format: application/pdf
    Format: application/pdf
    Format: 129-133
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  • 23
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26826 | 23782 | 2019-11-21 00:56:12 | 26826 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in the determination of K value which is an index to measure the enzymatic freshness of fish and squid. Specifically, reagents, apparatus and the analytical procedures needed and the calculations are presented.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
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  • 24
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26825 | 23782 | 2019-11-21 00:52:35 | 26825 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in measuring K value in fish meat by means of the freshness testing paper technique.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
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  • 25
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26802 | 23782 | 2019-11-12 05:28:20 | 26802 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in the measurement of pH in the fresh fish meat. Specifically, the procedures in sampling and sample preparation, apparatus and reagents required, and the analytical procedures are presented.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Microbiological analysis ; Fishery products ; Processed fishery products ; Fish inspection ; Fishery industry ; Food additives ; Food technology ; Standards ; Specifications ; pH
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  • 26
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26842 | 23782 | 2019-11-15 07:54:48 | 26842 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Starch is commonly used in the production of fish jelly products as an extender and as binding agent. The paper provides the methodology in the determination of starch in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the starch in a sample are provided.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Starch ; Additives ; Food additives
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  • 27
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26881 | 23782 | 2019-11-05 02:46:02 | 26881 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Monitoring and investigative work undertaken in the Philippines regarding dinoflagellate blooms are described. Chronological observations of the occurrence of red tides, aerial surveys, spatial distribution of the dinoflagellate and the physical environment are discussed. Fishing and the examination of gut content of fish and mussels and bioassay tests are detailed. Incidents of paralytic shellfish poisoning in the Philippines are considered briefly.
    Keywords: Fisheries ; Health ; Environmental monitoring ; Red tides ; Public health ; Medicine ; Dangerous organisms ; Philippines
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    Format: application/pdf
    Format: 52-79
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  • 28
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26885 | 23782 | 2019-11-05 02:23:34 | 26885 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: A report is made of the first incidence occurring of paralytic shellfish poisoning in Thailand in May 1983, following an extensive bloom of Trichodesmium erythraeum. Investigations undertaken regarding the source of the toxicity are outlined.
    Keywords: Fisheries ; Health ; Biological poisons ; Public health ; Red tides ; Shellfish ; Dangerous organisms ; Thailand
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    Format: application/pdf
    Format: 90-91
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  • 29
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26879 | 23782 | 2019-11-05 02:54:38 | 26879 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: A brief account is given of recent cases of paralytic shellfish poisoning in Sabah, Malaysia, and toxicological studies undertaken. Hydrography surveys, underwater observations after the occurrence of the red tides and plankton studies and monitoring of red tides are discussed.
    Keywords: Fisheries ; Health ; Shellfish ; Toxicity tests ; Red tides ; Public health ; Dangerous organisms ; Malaysia
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    Format: application/pdf
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  • 30
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26852 | 23782 | 2019-11-15 07:36:44 | 26852 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Cholera is an acute specific infection caused by the organism, Vibrio cholera. Diagnosis may be confirmed by the presence of large numbers of the comma-shaped bacilli on direct microscopic examination of a fecal or vomitus smear, and by the isolation of the organism on culture. Fish and shellfish have been identified as vehicles of cholera. Large numbers of V. cholera must usually be ingested to cause cholera. Thus problems often occur when poor handling and inadequate refrigeration have allowed the organism to multiply. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio cholerae
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26890 | 23782 | 2019-11-14 01:01:29 | 26890 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: Fishery statistics in Brunei Darussalam have been collected by the Department of Fisheries since the 1940s. In the early 1980s, a number of statistics were collected, such as catch and effort data of artisanal fishermen, aquaculture statistics, processing statistics as well as data from major wet markets focusing on the amount, prices of marketed fish either from the local fishermen or imported. In 1984, the collection of statistics on commercial fishing was started. The statistics have been used in the formulation of fishery management and development policies as well as for sectoral development. Following a brief account of the responsibility and statistic collections of the Department of Fisheries, an examination is made of employment in the fishery sector, fisheries production, fish marketed and the GDP for the fishery industry. Fisheries in Brunei Darussalam is a very healthy industry, where production is well below the maximum allowable harvestable limit of 20,000 tons at 30%. The Department is embarking to increase production from the capture fishery to reduce the country's dependence on imported fish; the same applies for aquaculture, in order to complement production from the capture fisheries. The processing sector is also increasing in importance, especially with the increase in the number of capture fishery licenses, and the demand for quality and value-added products.
    Keywords: Fisheries ; Marine fisheries ; Fishery statistics ; Aquaculture development ; Aquaculture statistics ; Fish catch statistics ; Marine aquaculture ; Freshwater aquaculture ; Fishery development ; Marine ; Brackish ; Freshwater
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26843 | 23782 | 2019-11-15 07:52:55 | 26843 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Sodium chloride is an important additive for the production of fish jelly products. It extracts the salt soluble protein to give the gel strength of the final product. The paper provides the methodology in the determination of the amount of sodium chloride in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the salt in a sample are provided.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Additives ; Food additives ; Salts ; Sodium chloride
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26851 | 23782 | 2019-11-14 01:29:31 | 26851 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Food poisoning due to Vibrio parahaemolyticus is a food-borne infection resulting from the ingestion of a large number of this organism (about 106-109 viable cells). The major symptoms are diarrhea and abdominal pain with headache, fever, and vomiting also occurring. The organisms are excreted during the acute stage of the illness after which they decrease rapidly. The differentiation of V. parahaemolyticus from other pathogenic species of Vibrio is based mainly on salt tolerance, Voges-Proskauer reaction, fermentation of sucrose, and growth at 43°C. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio parahaemolyticus ; Vibrio cholerae
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  • 34
    ISSN: 1432-1009
    Keywords: Limnology ; High mountain lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A general conceptual watershed-lake model of the complex interactions among climatic conditions, watershed location and characteristics, lake morphology, and fish predation was used to evaluate limnological characteristics of high mountain lakes. Our main hypothesis was that decreasing elevation in mountainous terrain corresponds to an increase in diversity of watershed size and lake area, depth, temperature, nutrient concentrations, and productivity. A second hypothesis was that watershed location and aspect relative to climatic gradients within mountainous terrain influences the limnological characteristics of the lakes. We evaluated these hypotheses by examining watershed location, aspect and size; lake morphology; water quality; and phytoplankton and zooplankton community characteristics among high mountain forest and subalpine lakes in Mount Rainier National Park. Although many of the comparisons between all forest and subalpine lakes were statistically insignificant, the results revealed trends that were consistent with our hypotheses. The forest lake group included more lakes with larger watersheds, larger surface areas, greater depths, higher concentrations of nutrients, and higher algal biovolumes than did the group of subalpine lakes. Deep lakes, which were mostly of the forest lake type, exhibited thermal stratification and relatively high values of some of the water-quality variables near the lake bottoms. However, the highest near-surface water temperatures and phytoplankton densities and the taxonomic structures of the phytoplankton and zooplankton assemblages were more closely related to geographical location, which corresponded to a west-east climate gradient in the park, than to lake type. Some crustacean and rotifer taxa, however, were limited in distribution by lake type. Fish predation did not appear to play an important role in the structure of the crustacean zooplankton communities at the genus level with the exception of Mowich Lake, where crustacean taxa were absent from the zooplankton community. This was the only lake inhabited by a true zooplanktivourous species of fish.
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  • 35
    ISSN: 1573-5133
    Keywords: Cyprinids ; Ethiopia ; Morphotypes ; Food-niche ; Biodiversity ; Feeding ; Evolution ; Fisheries ; Resource partitioning ; Piscivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis In October–December 1990, the large barbs (Barbus) that contribute more than 35% of the catch in lake Tana (northern Ethiopia) were studied. Previous authors (Rüppell 1837, Boulenger 1902,1911, Bini 1940) described from 6 to 23 (sub)species for the lake. Banister (1973) lumped all of these into one subspecies: Barbus intermedius intermedius Rüppell,1837. We found that the Lake Tana Barbus could be readily categorized in at least 13 discrete morphotypes, some of which were already distinguished by local fishermen. None of the known descriptions are adequate to distinguish the barbs unambiguously, which is important for monitoring and management of developing fisheries. Intermediates between morphotypes were rare (〈 10%). By applying canonical discriminant analysis on a set of 17 morphometric characters (including some directly associated with feeding) our initial morphotype-distinction was confirmed. Also, differences between the morphotypes in distribution, related to depth and substratum were found, as well as differences in intestinal contents, a key to the food-niche. The high number of piscivorous morphotypes (8 out of 13) was striking as piscivory is relatively rare among cyprinids. Piscivory was found to be highly correlated with morphological (feeding related) characters. The presence of discrete morphotypes, that also differ in food-niche and distribution, strongly suggests that several distinct populations exist, that may be (partly or completely) reproductively segregated. Knowledge about these populations, that may represent separate units of fish stock, is of crucial importance for the management of sustainable fisheries and protection of the biodiversity in Lake Tana. It is possible that several species or even a unique cyprinid species flock are present, that urgently need protection.
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  • 36
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 133-149 
    ISSN: 0886-1544
    Keywords: MAP4 depletion ; antibody blocking ; detyrosination ; midbody ; asymmetric cell processes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous immunolocalization studies using many primate cultured cell lines demonstrated that a microtubule-associated protein of Mr ∼210,000 which is now called MAP4, is present along the length of microtubules in interphase and mitotic cells [Bulinski and Borisy (1980) J. Cell Biol. 87:802-808; DeBrabander et al. (1981) J. Cell Biol. 91:438-455]. Since MAP4 has been implicated as a microtubule stabilizer, we asked whether all classes of microtubules possess an equal complement of MAP4. We have reexamined the cellular distribution of MAP4, using both conventional double-label immunofluorescence and an antibody blocking technique [Schulze and Kirschner (1987) J. Cell Biol. 104:277-288] to highlight microtubules lacking, or depleted in, MAP4. These techniques have revealed that thin processes extending from monkey kidney cells (TC-7), and those made by human neuroblastoma cells (IMR-32) in response to retinoic acid, are often deficient in MAP4 immunoreactivity. Since both types of cellular processes contain stable microtubules, which are enriched in detyrosinated (Glu) tubulin, we tested the ability of MAP4 to bind to microtubules made from pure Glu and pure tyrosinated (Tyr) tubulin in vitro. MAP4 bound to both types of microtubules, and the similar saturation level of MAP4 binding to Glu and Tyr microtubules suggested that differential binding to these forms of tubulin does not contribute directly to a mechanism for segregation of MAP4 on microtubules in vivo. In TC-7 cells, we also observed MAP4-depletion on single microtubules, distal regions of broad cytoplasmic extensions, and midbodies of dividing cells. MAP4 depletion may reflect recent, rapid growth of microtubules to which MAP4 has not yet bound, or the presence of other MAPs that may compete with MAP4 for binding sites on the MT. We suggest that different levels of MAP4 on microtubules may directly modulate microtubule dynamics within single cells, as well as other microtubule functions such as those involving microtubule motor activity. © 1994 Wiley-Liss, Inc.
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  • 37
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 193-205 
    ISSN: 0886-1544
    Keywords: amoeboid motility ; fluorescence ratio imaging ; BCECF ; nematodes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and locomotion of the amoeboid sperm of the nematode, Ascaris suum, depend on precise control of the assembly of their unique major sperm protein (MSP) filament system. We used fluorescence ratio imaging of cells loaded with BCECF to show that intracellular pH (pHi) is involved in controlling MSP polymerization in vivo. Spermatogenesis is marked by a cycle of MSP assembly-disassembly-reassembly that coincides with changes in pHi. In spermatocytes, which contain MSP in paracrystalline fibrous bodies, pHi was 6.8, 0.6 units higher than in spermatids, which disassemble the fibrous bodies and contain no assemblies of MSP filaments. Activation of spermatids to complete development resulted in rapid increase in pHi to 6.4 and reappearance of filaments. Treatment of spermatocytes with weak acids caused the fibrous bodies to disassemble whereas incubation of spermatids in weak bases induced MSP assembly. The MSP filaments in spermatozoa are organized into fiber complexes that flow continuously rearward from the leading edge of the pseudopod. These cells established a pseudopodial pH gradient with pHi 0.15 units higher at the leading edge, where fiber complexes assemble, than at the base of the pseudopod, where disassembly occurs. Acidification of these cells caused the MSP cytoskeleton to disassemble and abolished the pH gradient. Acid removal resulted in reassembly of the cytoskeleton, re-establishment of the pH gradient, and re-initiation of motility. MSP assembly in sperm undergoing normal development and motility and in cells responding to chemical manipulation of pHi occurs preferentially at membranes. Thus, we propose that filament assembly in sperm is controlled by pH-sensitive MSP-membrane interaction. © 1994 Wiley-Liss, Inc.
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  • 38
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 248-261 
    ISSN: 0886-1544
    Keywords: myogenesis ; protein isoforms ; muscle types ; Z-disc ; phosphorylation ; chicken muscle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphogenesis of functional myofibrils in chick skeletal and cardiac muscle occurs in greatly different time spans, in about 7 and 2 days, respectively. In chick skeletal myogenic cells, one isoform of the 250 kD actin-binding protein (ABP) filamin is associated with stress fiber-like structures of myoblasts and early myotubes, then disappears for approximately 4 days, whereupon a second filamin isoform reappears at the Z-disc periphery. We sought to determine if cardiac myogenesis involves this sequence of appearance, disappearance, and reappearance of a new filamin isoform in a compressed time scale. It was known that in mature heart, filamin is localized at the Z-disc periphery as in mature (fast) skeletal muscle, and is also associated with intercalated discs. We find that myocardial filamin has an apparent molecular weight similar to that of adult skeletal muscle filamin and lower than that of smooth muscle filamin, and that both skeletal and cardiac muscle contain roughly 200 filamin monomers per sarcomere. Two-dimensional peptide mapping shows that myocardial filamin is very similar to skeletal muscle filamin. Myocardial, slow skeletal, and fast skeletal muscle filamins are all phosphorylated, as previously shown for filamin of non-striated muscle. Using immunofluorescence, we found that filamin could not be detected in the developing heart until the 14-somite stage, when functional myofibrils exist and the heart has been beating for 3 to 4 hours. We conclude that in cardiac and skeletal myogenesis, different sequences of filamin gene expression result in myofibrils with similar filamin distributions and isoforms. © 1994 Wiley-Liss, Inc.
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  • 39
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 272-283 
    ISSN: 0886-1544
    Keywords: cell cycle ; transcription ; mRNA decay ; autoregulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The single alpha-tubulin gene of Tetrahymena thermophila was isolated from a genomic library and shown to encode a single protein. Comparisons of the rates of evolution of this gene with other alpha-tubulin sequences revealed that it belongs to a group of more evolutionarily constrained alpha-tubulin proteins in animals, plants, and protozoans versus the group of more rapidly evolving fungal and variant animal alpha-tubulins. The single alpha-tubulin of Tetrahymena must be used in a variety of microtubule structures, and we suggest that equivalently conserved alpha-tubulins in other organisms are evolutionarily constrained because they, too, are multifunctional. Reduced constraints on fungal tubulins are consistent with their simpler microtubule systems. The animal variant alpha-tubulins may also have diverged because of fewer functional requirements or they could be examples of specialized tubulins. To analyze the role of tubulin gene expression in regulation of the complex microtubule system of Tetrahymena, alpha-tubulin mRNA amounts were examined in a number of cell states. Message levels increased in growing versus starved cells and also during early stages of conjugation. These changes were correlated with increases in transcription rates. Additionally, alpha-tubulin mRNA levels oscillate in a cell cycle dependent fashion caused by changes in both transcription and decay rates. Therefore, as in other organisms, Tetrahymena adjusts alpha-tubulin message amounts via message decay. However the complex control of alpha-tubulin mRNA during the Tetrahymena life cycle involves regulation of both decay and transcription rates. © 1994 Wiley-Liss, Inc.
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  • 40
    Electronic Resource
    Electronic Resource
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    Cell Motility and the Cytoskeleton 28 (1994), S. 45-58 
    ISSN: 0886-1544
    Keywords: MTOC ; cytoplasmic microtubule complex ; antitubulin ; Immunofluorescence ; ultrastructure ; immunogold ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We investigated the microtubule (MT) cytoskeleton and microtubule centers (MTC) in undifferentiated amoebae by indirect immunofluorescence with six monoclonal antitubulin antibodies, and by transmission electron microscopy and immunogold ultracytochemistry. Interphase amoebae of both species contain a distinct cytoplasmic complex of MTs, which is more elaborate in Protostelium mycophaga. In Acytostelium leptosomum amoebae a single MTC is attached to each interphase nucleus at its pointed end, as in the other dictyostelid cellular slime molds Dictyostelium discoideum and Polysphondylium violaceum. Ultrastructurally, MTCs of A. leptosomum also resemble those of these two species: They consist of an electron-opaque core shaped like a stout rod, which is embedded, together with nodules, in a fuzzy matrix. The nodules are the points of origin of the MTs. In most amoebae of P. mycophaga there are two MTCs on opposite sides of and close to the nucleus, but many amoebae also contain a variable number of MTCs that are remote from the nucleus. Nucleus-associated and “remote” MTCs are structurally identical. They consist of a ring-shaped core with inner and outer diameters of ca. 130 nm and 340 nm. A plug sits in the ring, and satellites are connected to the core by fine fibrils. The satellites are the points of origin of MTs. New MTCs are apparently formed during mitosis, the parent MTC probably serving as a template for the genesis of a new ring. The results support the notion that phylogenetically related organisms have similarly constructed MTCs and that these are dissimilar in less closely related organisms. © 1994 Wiley-Liss, Inc.
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  • 41
    Electronic Resource
    Electronic Resource
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    Cell Motility and the Cytoskeleton 28 (1994), S. 135-142 
    ISSN: 0886-1544
    Keywords: bidirectional swimming ; flagellar movement ; helical bends ; 9+0 axoneme ; planar bends ; viscosity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatozoa of the small myzostomid worm Myzostomum cirriferum usually swim with the flagellum foremost but occasionally stop and then swim with the head foremost. The spermatozoa have axoneme of the 9+0 type; thus each lacks the central pair microtubules. The flagellum emerges in the anterior end of the cell body and attaches to it with junctions. To understand the mechanism regulating the swimming direction of the spermatozoa, we recorded the sperm and their flagellar movements using a video camera with a high-speed shutter. The effects of calcium and viscosity on these movements were also examined.The cell body with the flagellum attached to it formed a curved plate during beating, while the free portion of the flagellum beats with small helical bends. Motive force to propel a spermatozoon was mainly due to the bends in the cell body. The spermatozoa reversed the direction of their swimming as a result of a change in the direction of bend propagation. The direction of bend propagation was regulated by calcium; the bends in the cell body propagated from the end of the head toward the free portion of the flagellum at low concentrations of Ca2+, whereas the direction of bend propagation was reversed at high concentrations of this ion. High viscosity of the medium stimulated a change in the direction of bend propagation. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 155-164 
    ISSN: 0886-1544
    Keywords: microfilamentous cytoskeleton ; actin binding proteins ; formyl peptides ; ionic extraction ; immunoblots ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: F-actin is a major component of the neutrophil (PMN) cytoskeleton. In basal PMNs, F-actin exists in two structurally and functionally distinct pools: Triton insoluble F-actin (TIF)-cold insensitive, not depolymerizable by dilution, and distributed in pseudopods and submembranous locations; and Triton soluble F-actin (TSF)-unstable in cold, diffusely distributed, and gelsolin enriched. The element(s) conferring these unique properties to the Triton insoluble F-actin pool are unknown, but logically include distinct actin regulatory proteins. To study the morphologic and functional determinants of the Triton insoluble F-actin pool, the distribution and quantity of three candidate regulatory proteins, α-actinin, tropomyosin (TM), and actin binding protein (ABP-280), were compared in F-actin (Triton insoluble and Triton soluble) and G-actin pools isolated from basal and chemotactic factor activated human PMNs in suspension, using immunoblots and ionic extraction. F-actin content was measured by NBDphallacidin binding and gel scans. The results show that: (1) α-actinin, actin binding protein 280, and tropomyosin are localized to TIF and excluded from TSF; (2) TM, α-actinin, and ABP 280 are required to stabilize fractions of Triton insoluble F-actin in PMNs; and (3) chemotactic factor activation results in release of a fraction of TM from the Triton insoluble F-actin pool in temporal association with F-actin polymerization in the Triton insoluble F-actin pool. Shifts in ABP 280 or α-actinin do not occur. The results suggest that TM, α-actinin, and ABP 280 provide structure to TIF and that TM release from TIF is involved in chemotactic factor induced actin polymerization in PMNs. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 165-178 
    ISSN: 0886-1544
    Keywords: WISH ; Keratin ; 3-D reconstruction ; mitosis ; intermediate filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three dimensional (3-D) reconstruction of four mitotic WISH cells from ultrathin sections gave an informative representation of the spatial distribution of keratin densities in these cells. The correspondence between the densities as studied by transmission electron microscopy (TEM) and the Keratin bodies initially revealed by immunoflourescent colabeling of cultures, was confirmed by immunoelectron-microscopy. The smaller, and sometimes more elongated densities, were relatively abundant just beneath the subplasmalemmal microfilament band; and at certain levels of the mitotic cell they were observed to be connected to neighboring densities by intact intermediate filaments (IFs). The larger and more spherical densities appeared to be somewhat more discrete and randomly distributed. Other observed associations of the keratin densities included the telophase contractile ring of microfilaments, chromosomes, the reformed telophase nucleus, and desmosomal junctions with neighboring interphase cells. Cytochalasin D (CD) treatment of cells displaced the peripheral keratin densities toward the cell membrane. The density volume constituted 0.52% to 1.57% of the total cell volume, and the proportional density size was decreased in the cells that had progressed into anaphase and telophase. The observed formation and subsequent dissolution of keratin densities during mitosis may represent a dynamic mechanism of restructuring the keratin cytoskeleton in an unpolymerized form in order to allow for rapid reformation of interphase cell junctions. The physical associations observed between intact IFs and the keratin densities may provide support at certain depths of the mitotic cell, and the juxtaposition of densities with nuclear components suggests a possible source of and role for keratin IFs during nuclear events. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 199-204 
    ISSN: 0886-1544
    Keywords: axoneme ; cilia ; flagella ; microtubule ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Observations that were interpreted to provide evidence for equivalent functions of all axonemal dyneins should be reinterpreted, and models based on this assumption should be abandoned. In the future, attempts to understand the mechanisms for flagellar bending, oscillation, and bend propagation should start from the assumption that each type of axonemal dynein may have a specific function. At least three distinct functions can now be identified: bend initiation, maintenance of the angle of propagating bends, and generation of power to overcome viscous resistances. Only the last of these three functions is an outer arm dynein function. © 1994 Wiley-Liss, Inc.
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  • 45
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    Keywords: cytoskeleton ; actin binding ; transgelin sequence ; gelation ; gene family ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used degenerate oligonucleotides, derived from the amino acid sequence of transgelin peptides [Shapland et al., 1993: J. Cell Biol. 121:1065-1073], to isolate and sequence overlapping cDNA clones encoding this actin gelling protein. Primers with 5′ restriction enzyme sites directed against the N and C terminal amino acids present in these clones were then used to amplify and clone the entire transgelin coding region from reverse transcribed rat small intestine cDNA (RT-PCR). These studies have shown that transgelin is the product of a single gene which is conserved between yeast, Drosophila, molluscs, and humans. Transgelin is expressed as a single message that is regulated at the level of transcription in SV40 transformed 3T3 cells. Our data have shown that transgelin and several other proteins of unknown function, SM22α [Pearlstone et al., 1987: J. Biol. Chem. 262:5985-5991], mouse p27 [Almendral et al., 1989: Exp. Cell Res. 181:518-530], and human WS3-10 [Thweatt et al., 1992: Biochem. Biophys. Res. Commun. 187:1-7], share extensive homology. More limited regions of homology shared between transgelin and other proteins such as rat NP25 (unpublished), chicken calponins α and β [Takahashi and Nadal-Ginard, 1991: J. Biol. Chem. 266:13284-13288], and Drosophila mp20 [Ayme-Southgate et al., 1989: J. Cell Biol. 108:521-531] suggest that all of these proteins may be classified as members of a new transgelin multigene family. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 279-284 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 47
    ISSN: 0886-1544
    Keywords: cytoskeleton ; cell culture ; gene expression ; Northern blot ; serum-induction ; rat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin D and dBcAMP cause cultured astrocytes to change from flat cells to retrated process-bearing cells. F-actin was present throughout cells stimulated with dBcAMP for 16 h, whereas cytochalasin D caused F-actin to form massive aggregates at the tips of the cell processes. The two drugs differently regulated the expression of both β-actin and tropomyosin genes in astrocytes cultured in the presence or absence of serum: dBcAMP caused down-regulation and cytochalasin D caused up-regulation. Northern blot analyses indicated that: (1) serum deprivation halved the concentration of all tropomyosin transcripts (TM-1, TM-2, TM-4, TMBr-1, TMBr-2). Serum induced TM-4 via transcriptional activation, independent of protein synthesis, (2) dBcAMP induced down-regulation of β-actin (-50%) and tropomyosin transcripts (-35 to 52%) even in the presence of serum. The concentration of profilin mRNA decreased in dBcAMP-reactive astrocytes (-46%). The decrease in β-actin mRNA concentration was not blocked by cycloheximide, whereas down-regulation of tropomyosin transcripts was completely reversed when protein synthesis was inhibited, and (3) cytochalasin D induced an increase in the concentration of tropomyosin transcripts (+ 69 to 185%) which was cumulative with serum stimulation. Cytochalasin D induction of both β-actin and TM-4 operated through transcriptional activation, independent of protein synthesis.The production of all tropomyosin transcripts examined here were strictly coordinated with β-actin expression in serum-, dBcAMP- and cytochalasin D-treated astrocytes. This indicates that the differential expression of tropomyosin isoforms occurring during astrocyte maturation is due to more complex regulation than that involved in serum- or cAMP-stimulated astrocytes. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 333-345 
    ISSN: 0886-1544
    Keywords: ciliary beat frequency ; metachronal wave ; ciliary coupling ; extracellular ATP ; acetylcholine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the present work we measured in real time the metachronism and degree of correlation between beating cilia from cultured mucociliary epithelium. The method is based on simultaneous measurement of ciliary beat frequency, phase shifts, and correlation factors in two directions: parallel and perpendicular to the effective stroke direction (ESD). From the phase shifts the lengths of wave components, and consequently the metachronal wavelength and direction, were evaluated.On active ciliary areas of cultured frog esophagus under normal conditions, a relatively high degree of correlation is observed, but cilia are more correlated in direction parallel to ESD which is also the direction of the mucus propulsion. The length of the wave component parallel to ESD is more than twice as large as that of the perpendicular component. The metachronal wavelength was found to be in the range of 5-9 μm, and the direction of the wave propagation was in the range of 90°-125° clockwise to the ESD.When ciliary beat frequency was rapidly increased by extracellular ATP or acetylcholine, only minor effects were observed on the degree of correlation between beating cilia. The length of the wave component parallel to ESD showed the most dramatic effect increasing up to tenfold. The perpendicular to ESD component was not affected by the stimulation. Consequently, the metachronism became more laeoplectic with the angle between the ESD and the wave directions decreasing by 10°-30°, and the metachronal wavelength remained unaltered. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 57-71 
    ISSN: 0886-1544
    Keywords: microtubule bundling ; cytoskeleton ; tau ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule protein extracted from dogfish erythrocyte cytoskeletons by disassembly of marginal bands at low temperature formed linear microtubule (MT) bundles upon reassembly at 22°C. The bundles, which were readily visible by video-enhanced phase contrast or DIC microscopy, increased in length and thickness with time. At steady state after 1 hour, most bundles were 6-11 μm in length and 2-5 MTs in thickness. No inter-MT cross-bridges were visible by negative staining. The bundles exhibited mechanical stability in flow as well as flexibility, in this respect resembling native marginal bands. As analyzed by SDS-PAGE and immunoblotting, our standard extraction conditions yielded MT protein preparations and bundles containing tau protein but not high molecular weight MAPs such as MAP-2 or syncolin. In addition, late fractions of MT protein obtained by gel filtration were devoid of high molecular weight proteins but still produced MT bundles. The marginal band tau was salt-extractable and heat-stable, bound antibodies to mammalian brain tau, and formed aggregates upon desalting. Antibodies to tau blocked MT assembly, but both assembly and bundling occurred in the presence of antibodies to actin or syncolin. The MTs were “unbundled” by subtilisin or by high salt (0.5-1 M KCl or NaCl), consistent with tau involvement in bundling. High salt extracts retained bundling activity, and salt-induced unbundling was reversible with desalting. However, reversibility was observed only after salt-induced MT disassembly had occurred. Reconstitution experiments showed that addition of marginal band tau to preassembled MTs did not produce bundles, whereas tau presence during MT reassembly did yield bundles. Thus, in this system, tau appears to play a role in both MT assembly and bundling, serving in the latter function as a coassembly factor. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 82-93 
    ISSN: 0886-1544
    Keywords: trichomonads ; cytoskeleton ; antibodies ; electrophoresis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The production of monoclonal antibodies and the use of biochemical techniques revealed that B-type costa proteins in trichomonads are composed of several major polypeptides with molecular weight detected between 100 and 135 kDa similar to those found in the A-type costae. Although differences were observed between the two types in their fine structure, we tested whether proteins composing the two costa types belong to the same protein family. A polyclonal antibody produced against the 118 kDa costa protein of Trichomonas vaginalis also recognized a 118 kDa costa protein in all other trichomonad genera studied so far whether they have A- or B-type costae. Moreover biochemical characteristics of costa proteins indicated that these proteins might represent a novel class of striated root-forming proteins in addition to centrin, giardin, and assemblin. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 110-116 
    ISSN: 0886-1544
    Keywords: high-molecular weight MAPs ; microfilaments ; microtubules ; low-shear viscometry ; taxol ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: High molecular weight microtubule-associated proteins MAP1A and MAP2 form thin projections from microtubule surfaces and have been implicated in crosslinking microtubules and other cytoskeletal components. We have purified native MAP1A from bovine brain and have studied its interaction with G- and F-actin. Using a solid-phase immunoassay we show that MAP1A binds in a dose-dependent manner to both G-actin and F-actin. Addition of MAP1A to F-actin causes gelation of F-actin and SDS-PAGE analysis shows that MAP1A co-sediments with the gelled network, under conditions where F-actin alone does not pellet. The low apparent viscosity of F-actin is markedly increased in the presence of MAP1A, suggesting that MAP1A can crosslink F-actin. Co-incubation experiments indicate that MAP1A and MAP2 may bind to common or overlapping sites on the actin molecule. The widespread distribution of MAP1A and its interaction with microtubules, actin, and intermediate filaments suggests that it may constitute an important determinant of neuronal and non-neuronal cellular morphology. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 141-154 
    ISSN: 0886-1544
    Keywords: dynein arms ; nexin links ; radial spokes ; relaxation oscillator ; doublet microtubules ; biological oscillators ; computer model ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ciliary and flagellar motion is driven by the dynein-tubulin interaction between adjacent doublets of the axoneme, and the resulting sliding displacements are converted into axonemal bends that are propagated. When the axoneme is bent in the normal beating plane, force develops across the axoneme in the plane of the bend. This transverse force (t-force) has maximal effect on the interdoublet spacing of outer doublets 2-4 on one side of the axoneme and doublets 7-9 on the opposite side. Episodes of sliding originates as the t-force brings these doublets into closer proximity (allowing dynein bridges to form) and are terminated when these doublets are separated from each other by the t-force. A second factor, the adhesive force of the dynein-tubulin attachments (bridges), also acts to pull neighboring doublets closer together. This force resists termination of a sliding episode once initiated, and acts locally to give the population of dynein bridges a type of excitability. In other words, as bridges form, the probability of nearby bridges attaching is increased by a positive feedback exerted through the interdoublet spacing. A conceptual working hypothesis explaining the behavior of cilia and flagella is proposed based on the above concepts. Additionally, the feasibility of this proposed mechanism is demonstrated using a computer simulation. The simulation uses a Monte Carlo-type algorithm for dynein attachment and adhesive force, together with a geometric evaluation of the t-force on the key microtubule pairs. This model successfully develops spontaneous oscillations from any starting configuration (including a straight position). It is compatible with the physical dimensions, mechanical properties and bridge forces measured in real cilia and flagella. In operation, it exhibits many of the observed actions of cilia and flagella, most notably wave propagation and the ability to produce both cilia-like and flagella-like waveforms. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 195-203 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
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    Cell Motility and the Cytoskeleton 29 (1994), S. 339-344 
    ISSN: 0886-1544
    Keywords: microfilament ; phalloidin ; immunoblotting ; immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anti-actin monoclonal antibodies were prepared using phalloidin-stabilized actin that was purified from pea roots by DNase I affinity chromatography. One monoclonal antibody, designated mAb3H11, bound plant actin in preliminary screenings and was further analyzed. Immunoblot analysis showed that this antibody had a high affinity for plant actin in crude and purified preparations but a low affinity for rabbit muscle actin. In immunoblots of plant extracts separated on two-dimensional gels it appeared to bind all actin isoforms recognized by the JLA20 anti-chicken actin antibody. Using immunofluorescent cytochemistry, the antibody was used to observe actin filaments in aldehyde-fixed and methanol-treated tobacco protoplasts. These results indicate that mAb3H11 should be a useful reagent for the study of plant actins. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 366-374 
    ISSN: 0886-1544
    Keywords: cytoskeleton ; microfilaments ; cytochalasin ; gravity ; amiprophos-methyl ; tip-growth ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Apical cells of protonemata of the moss Ceratodon purpureus are unusual among plant cells with sedimentation in that only some amyloplasts sediment and these do not fall completely to the bottom of vertical cells. To determine whether the cytoskeleton restricts plastid sedimentation, the effects of amiprophos-methyl (APM) and cytochalasin D (CD) on plastid position were quantified. APM treatments of 30-60 min increased the plastid sedimentation that is normally seen along the length of untreated or control cells. Longer APM treatments often resulted in more dramatic plastid sedimentation, and in some cases almost all plastids sedimented to the lowermost point in the cell. In contrast, the microfilament inhibitor CD did not affect longitudinal plastid sedimentation compared to untreated cells, although it did disturb or eliminate plastid zonation in the tip. These data suggest that microtubules restrict the sedimentation of plastids along the length of the cell and that microtubules are load-bearing for all the plastids in the apical cell. This demonstrates the importance of the cytoskeleton in maintaining organelle position and cell organization against the force of gravity. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 26-40 
    ISSN: 0886-1544
    Keywords: cleavage furrows ; cytokinesis ; actin ; phalloidin ; myosin ; filamin ; talin ; attachment plaques ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: PtK2 cells of exceptionally large size were microinjected with fluorescently labeled probes for actin, myosin, filamin, and talin in order to follow the assembly of the contractile proteins into the cleavage furrows. Whereas in cells of normal size, there is usually a diffuse pattern of localization of proteins in the cleavage furrow, in these large, flat cells the labeled proteins localized in fibers in the cleavage furrow. Often, the fibers were striated in a pattern comparable to that measured in the stress fibers of the same cell type. The presence of talin in discrete plaques along fibers in the cleavage furrows of the large cells suggests a further similarity between cleavage furrow and stress fiber structure. The presence of filamin in the cleavage furrows also suggests the possibility of an overlapping mechanism in addition to that of a talin mediated mechanism for the attachment of actin filaments to the cell surfaces in the cleavage furrow. A model is presented that emphasizes the interrelationships between stress fibers, myofibrils, and cleavage furrows. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 69-78 
    ISSN: 0886-1544
    Keywords: kinesin ; dynein ; MAP-motor interactions ; microtubule arrays ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Bundles of native microtubules isolated from the ovarioles of hemipteran insects are seen to shimmer when observed using dark-field microscopy. This novel form of microtubule motility becomes even more obvious when the isolated bundles are detergent-extracted and reactivated. We have studied the nucleotide-specificity and the drug-sensitivity of microtubule shimmering in order to obtain information regarding the nature of the motor protein responsible, and to compare its properties with those of previously characterised microtubule motors. The involvement of structural MAPs in the shimmering and in maintenance of microtubule bundles in this system has also been investigated. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 88-96 
    ISSN: 0886-1544
    Keywords: cell movement ; speed ; persistence time ; colcemid ; alveolar macrophage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of microtubules in random cell migration was investigated using time-lapse videomicroscopy to record in vitro the shape and motile behavior of guinea pig alveolar macrophages before and after disrupting microtubules with colcemid. Cell migration was quantified in terms of directional persistence time and speed. Motility was also correlated with morphological polarity: cells having a single lamellipodal region (monopolar cells) migrated, whereas those lacking a lamellipod (apolar cells) or with opposing lamellipodal regions (bipolar cells) did not migrate. Within 2 hours, colcemid caused a shift in polarity from 80% monopolar cells to 40% monopolar and 40% bipolar cells and a corresponding decrease from 80% to 40% in the fraction of migrating cells. Mean persistence time and speed decreased only slightly (approximately 20%) for those cells (still monopolar) which continued to migrate in the presence of colcemid. Persistence time and speed actually increased for many individual cells, indicating that random migration did not require intact microtubules. We conclude that colcemid treatment destabilizes monopolarity, leading to the gradual loss of monopolarity and consequent inhibition of migration. While a cell remains monopolar, it will continue to migrate even in the absence of intact microtubules, but microtubules are required for the long-term maintenance of cellular monopolarity and, thus, for continued motility. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 27 (1994), S. 262-271 
    ISSN: 0886-1544
    Keywords: 3T3 cells ; cell motility ; infrared ; phototaxis ; centrosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous experiments have suggested that 3T3 cells were able to extend pseudopodia toward latex particles up to 60 μm away from the cell body if the particles were irradiated by an infrared beam in the range of 700-900 nm [Albrecht-Buehler, 1991: J. Cell Biol. 114:493-502]. The present article reports that this response of cells to infrared light can be inhibited if the cell center is simultaneously irradiated with a beam of the same light. In marked contrast, the cells responded normally to the presence of infrared light scattering particles if the second beam irradiated other parts of the cell body. The results imply that the cellular mechanism of infrared detection is located at the cell center. The infrared sensing mechanism remains intact in enucleated cells and in cells which were incubated in monensin to vesiculate their Golgi apparatus and inhibit their Golgi functions. Accordingly, it is proposed that the centrosome which contains the centrioles is the only remaining candidate in the cell center for a cellular detection device for the direction of infrared signal sources. The results support an earlier suggestion that centrioles may be such detection devices [Albrecht-Buehler, 1981: Cell Motil. Cytoskeleton 1:237-245]. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 206-218 
    ISSN: 0886-1544
    Keywords: sperm motility ; sperm maturation ; flagella ; protein kinases ; protein kinase inhibitor ; cGMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ejaculated ram sperm were demembranated with Triton X-100, separated from the detergent-soluble matrix, and reactivated [San Agustin and Witman (1993): Cell Motil. Cytoskeleton 24:264-273]. The percent motility of models prepared from freshly washed sperm was comparable to that of the washed sample before demembranation, regardless of whether cAMP was included in the reactivation medium. However, demembranated models derived from aging or metabolically inhibited sperm exhibited a lower percent reactivation and required cAMP to attain the level of motility of freshly washed sperm. Cyclic AMP was ∼100 times more effective than cGMP. The requirement for cAMP could be bypassed by addition of porcine heart cAMP-dependent protein kinase (PKA) catalytic subunit to the reactivation medium, demonstrating that cAMP was acting via PKA. The cAMP stimulation of reactivation was not affected by inclusion of the PKA inhibitor PKI(5-24) in the reactivation medium, but was decreased when the models were preincubated with PKI(5-24) prior to reactivation. The cytosol-free models retained 〉90% of the sperm PKA activity; therefore, the PKA appears to be anchored to internal sperm structures. This PKA could not be extracted by cAMP or Triton X-100 alone, but only by cAMP and Triton X-100 in combination. We conclude that cAMP-dependent protein phosphorylation is critical for sperm motility, but that the essential protein phosphate sites turn over slowly under our reactivation conditions, so that the cAMP requirement is apparent only in models prepared from sperm having a low internal ATP or cAMP content. Interestingly, reactivation was rapidly blocked by the peptide arg-lys-arg-ala-arg-lys-glu, which has been reported to be a selective inhibitor of cGMP-dependent protein kinase. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 286-286 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 27 (1994), S. 287-298 
    ISSN: 0886-1544
    Keywords: cilium ; flagellum ; motility ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A physical model developed to explain microtubule sliding patterns in the trypsintreated ciliary axoneme has been extended to investigate the generation of bending moments by microtubules sliding in an axoneme in which the dublets are anchored at one end. With sliding restricted, a bending moment is developed by the polarized shearing interaction between neighbouring doublets, effected by the activity of dynein arms on doublet N pushing N + 1 in a tipward ( + ) direction. In arrested axonemes in which arms on several contiguous doublets are active, the bending moment causes splitting of the 9 + 2 microtubule array into two or more sets of doublets. In the absence of special constraints, splitting depends only on breaking the circumferential interdoublet links most distorted by the bending moment. The analysis, which permits assignment of arm activity to specific microtubules in each of the observed patterns of splitting, indicates that the axoneme will split between doublet N and N + 1 if arms on doublet N are inactive and arms on either N + 1 or N-1 are active. To produce the observed major splits, dynein arms on the microtubules of roughly one-half of the axoneme are predicted to be active, in a manner consistent with the switch-point hypothesis of ciliary motion. Electron microscopic examination indicates that virtually every set of doublets in the split axonemes retains its cylindrical form. Maintenance of cylindrical symmetry can be ascribed to the mechanical properties of the unbroken links, which may resist both tensile and compressive stress, and to active dynein arms. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 361-372 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 28 (1994) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 28 (1994), S. 195-198 
    ISSN: 0886-1544
    Keywords: baculovirus ; tau ; MAP2 ; neuronal cytoskeleton ; growth cones ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The phenotypes induced by the expression of neuronal microtubule-associated proteins (MAPs) in Sf9 cells have provided data on the in situ function of these proteins. Both MAP2 and tau can induce long processes in Sf9 cells, and the processes contain bundles of microtubules. In both cases the microtubules are aligned with their plus ends distal. Tau expression usually induces a single process that is unbranched and of uniform caliber. Processes can form even when the cells are grown in suspension. Microtubules do not extend all the way to the tip; instead the terminal region contains an actin-rich meshwork. Taxol treatment of Sf9 cells also induces the assembly of microtubules into bundles but does not induce process formation in Sf9 cells. Therefore the in vitro properties of tau as a molecule capable of assembling, stabilizing, and bundling microtubules do not fully account for the in vivo ability of tau alone to transduce microtubule assembly into a change in cell shape. The morphological features of the processes induced by MAP2 differ in highly informative ways. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 231-242 
    ISSN: 0886-1544
    Keywords: squid axoplasm ; organelle movement ; calmodulin ; actin filaments ; axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It was recently shown that, in addition to the well-established microtubule-dependent mechanism, fast transport of organelles in squid giant axons also occurs in the presence of actin filaments [Kuznetsov et al., 1992, Nature 356:722-725]. The objectives of this study were to obtain direct evidence of axoplasmic organelle movement on actin filaments and to demonstrate that these organelles are able to move on skeletal muscle actin filaments. Organelles and actin filaments were visualized by video-enhanced contrast differential interference contrast (AVEC-DIC) microscopy and by video intensified fluorescence microscopy. Actin filaments, prepared by polymerization of monomeric actin purified from rabbit skeletal muscle, were stabilized with rhodamine-phalloidin and adsorbed to cover slips. When axoplasm was extruded on these cover slips in the buffer containing cytochalasin B that prevents the formation of endogenous axonal actin filaments, organelles were observed to move at the fast transport rate. Also, axoplasmic organelles were observed to move on bundles of actin filaments that were of sufficient thickness to be detected directly by AVEC-DIC microscopy. The range of average velocities of movement on the muscle actin filaments was not statistically different from that on axonal filaments. The level of motile activity (number of organelles moving/min/field) on the exogenous filaments was less than on endogenous filaments probably due to the entanglement of filaments on the cover slip surface. We also found that calmodulin (CaM) increased the level of motile activity of organelles on actin filaments. In addition, CaM stimulated the movement of elongated membranous organelles that appeared to be tubular elements of smooth endoplasmic reticulum or extensions of prelysosomes. These studies provide the first direct evidence that organelles from higher animal cells such as neurons move on biochemically defined actin filaments. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 265-277 
    ISSN: 0886-1544
    Keywords: intermediate filament proteins ; vimentin ; domain function ; filament assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although the head and rod domains of intermediate filament (IF) proteins are known to play significant roles in filament assembly, the role of the tail domain in this function is unclear and the available information supports contradictory conclusions. We examined this question by comparing transfection of the same cDNA constructs, encoding vimentins with modified tail domains, into cell lines that do and do not contain endogenous IF proteins. By this approach, we were able to distinguish between the ability of a mutant IF protein to initiate assembly de novo, from that of incorporating into existing filament networks. Vimentins with modifications at or near a highly conserved tripeptide, arg-asp-gly (RDG), of the tail domain incorporated into existing IF networks in vimentin-expressing (vim+) cells, but were assembly-incompetent in cells that did not express IF proteins (vim-). The failure of the RDG mutant vimentins to assemble into filament arrays in vim- cells was reversible by re-introducing a wild-type vimentin cDNA, whereupon both wild-type and mutant vimentins coassembled into one and the same IF network. We conclude that the function of the tail domain of type III IF proteins, and possibly of keratins K8 and K18, in IF assembly is distinct from those of other domains; a region encompassing the RDG tripeptide appears to be important in the assembly process. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 327-332 
    ISSN: 0886-1544
    Keywords: tubulin ; isoforms ; Atlantic cod ; Antarctic fish ; evolutionary aspects ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dynamic instability of microtubules free of microtubule-associated proteins from two genera of cold-living fishes was measured, by means of video-enhanced differential interference-contrast microscopy, at temperatures near those of their habitats. Brain microtubules were isolated from the boreal Atlantic cod (Gadus morhua; habitat temperature ∽ 2-15°C) and from two austral Antarctic rockcods (Notothenia gibberifrons and N. coriiceps neglecta; habitat temperature ∽ -1.8 to + 2°C). Critical concentrations for polymerization of the fish tubulins were in the neighborhood of 1 mg/ml, consistent with high interdimer affinities. Rates of elongation and frequencies of growth-to-shortening transitions (“catastrophes”) for fish microtubules were significantly smaller than those for mammalian microtubules. Slow dynamics is therefore an intrinsic property of these fish tubulins, presumably reflecting their adaptation to low temperatures. Two-dimensional electrophoresis showed striking differences between the isoform compositions of the cod and the rockcod tubulins, which suggests that the cold-adapted microtubule phenotypes of northern and southern fishes may have arisen independently. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 29 (1994), S. 97-109 
    ISSN: 0886-1544
    Keywords: calcium ; flagellar movement ; mechanotransduction ; mechanoshock response ; Spermatozopsis similis ; video analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The biflagellate green alga Spermatozopsis similis exhibits a remarkable avoidance reaction in addition to the photophobic or stop response characteristic of such algae. S. similis normally swims forward with its anteriorly attached flagella directed posteriorly and propagating sine-like waves from base to tip. Upon contact with surfaces or other cells, S. similis responds with rapid backward swimming, covering distances of up to 50 μm in 140 to 220 msec. This reaction, which we term the mechanoshock response, also can be triggered by vigorous mechanical stimulation, but not by physiological light intensities. It consists of 3 phases: (1) a rapid acceleration phase with average duration of 31 msec; (2) a phase of about 66 msec with constant high speed (maximal velocities of 〉 600 μm·sec-1) or slow deceleration; and (3) a deceleration phase of ∼ 83 msec, followed by a stop or short period of circling. The cells then resume forward swimming in a random direction. Prior to the mechanoshock response the flagella rapidly are brought together into a close parallel configuration extending anteriorly of the cell body. They then appear to propel the cell by undulatory beating, while the cell describes a pronounced helical path. Small decreases in the extracellular Ca2+ concentration, as well as low concentrations of Ba2+, strongly suppress the probability of this phobic reaction. We conclude that this mechanoshock response involves large Ca2+ influxes, probably mediated by mechanosensitive and/or stretch-activated ion-channel(s). © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 155-166 
    ISSN: 0886-1544
    Keywords: Golgi vesicles ; pollen ; pollen tube ; microtubules ; kinesin-related protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A 100-kDa polypeptide with microtubule-interacting properties was identified in a Golgi vesicle-enriched fraction from Corylus avellana pollen. The k71s23 antibody (directed to the kinesin heavy chain from bovine brain) [Tiezzi et al., 1992: Cell Motil. Cytoskeleton 21:132-137] localized the polypeptide on the external surface of membrane-bounded organelles. Some 100-kDa-containing vesicles co-pelleted with microtubules (polymerized from purified bovine brain tubulin) either in presence or absence of 5 mM AMPPNP, but they could be released by 10 mM ATP or 0.5 M KCl. The pollen microtubule-interacting protein, salt-extracted from membranes and partially purified by gel filtration, exhibited an ATPase activity (16.2 nmolPi/mg/min) which could be stimulated about 2-fold (32.5 nmolPi/mg/min) by addition of bovine brain microtubules. We suppose that the 100-kDa polypeptide is part of a molecular complex showing properties of the kinesin class. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 177-185 
    ISSN: 0886-1544
    Keywords: flagella ; Chalamydomonas ; mutant ; high-frequency vibration ; nanometer scale measurement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Flagellar axonemes of sea urchin sperm display high frequency (200-400 Hz) vibration with nanometer scale amplitudes in the presence of ATP [Kamimura and Kamiya, 1992: J. Cell Biol. 116:1443-1454]. To investigate how various axonemal components affect the vibration, we examined vibration in wild-type and mutant axonemes of Chlamydomonas. At 1 mM ATP, wild-type axonemes underwent vibration at 100-650 Hz with amplitudes of 4-40 nm. This vibration was similar to, but less regular than, that in sea urchin sperm. Axonemes of the mutants ida1 and ida4 lacking part of the inner arm dynein underwent vibrations indistinguishable from that of wild-type. The mutant oda1 lacking the entire outer arm underwent vibration at about half the wild-type frequency. Unexpectedly, the paralyzed mutants pf18 lacking the central pair and pf14 lacking the radial spokes displayed vibration with significantly higher frequencies and smaller amplitudes than those in the wild-type vibration. These results indicate that the high-frequency vibration is common to many kinds of mutant axonemes that lack various axonemal substructures, but that its manner is sensitive to the presence of outer arm dynein and the central pair/radial spoke system. Simultaneous measurements of amplitude and frequency in wild-type and mutant axonemes suggest that the velocity of microtubule sliding in vibrating axonemes is lower than the velocity of sliding under load-free conditions. The velocity is particularly low in pf18. A possible mechanism is proposed to explain the lower sliding velocity and vibration amplitude in the pf18 axoneme, based on an assumption that central pair/radial spoke system may work to regulate the switching of two antagonizing forces within the axoneme. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 215-224 
    ISSN: 0886-1544
    Keywords: cytoplasmic dynein ; Paramecium ; monoclonal antibody ; 12S dynein ; microtubule gliding ; Km and Vmax ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In an earlier study we reported the isolation of a cytoplasmic dynein from the cytosol of Paramecium multimicronucleatum. In this study we report the isolation and characterization of two cytosolic axonemal dyneins (22S and 12S) as well as a 19S cytoplasmic dynein from the cytosol of whole or deciliated cells using preformed bovine brain microtubules. These three dynein species were characterized according to mass, morphology, vanadate photocleavage patterns, CTPase/ATPase ratios, Km and Vmax values, temperature optima and reactivity with a mAb. For comparison, 22S and 12S axonemal dyneins (ADs) were also isolated and purified from the demembranated axonemes. The 22S and 12S soluble dyneins appear to be related to ciliary ADs in that the 22S soluble dynein is three-headed while the 12S is a one-headed dynein, as determined by negative staining. Ciliary ADs and their corresponding 22S and 12S soluble dyneins isolated from the cytosol also have similar Km and Vmax values as well as vanadate photocleavage patterns and temperature optima. A mAb raised against the soluble 22S dynein reacted with the 22S ciliary dyneins but not the 12S axonemal or the 19S cytoplasmic dynein. All isolated dyneins supported similar microtubule gliding rates but had different ionic requirements for the translocation buffer. These results suggest that: (i) the two soluble 22S and 12S dyneins are precursor molecules of the ciliary dyneins, (ii) the subunits of the outer arm dynein are already assembled in the cytosol as a three-headed bouquet, and (iii) the 22S and 12S soluble dyneins are functional prior to being transported and attached to the axonemes of the cilia. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 29 (1994), S. 280-290 
    ISSN: 0886-1544
    Keywords: mitosis ; phosphorylation ; protein phosphatase ; okadaic acid ; mitotic apparatus ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A protein component of isolated mitotic apparatus having a relative molecular mass of 62,000 (p62) is a substrate of a calcium/calmodulin dependent protein kinase, and the phosphorylation of p62 in vitro correlates directly with microtubule disassembly. In vivo experiments have determined the phosphorylation of p62 increases after fertilization; maximum incorporation of phosphate occurs during late metaphase/early anaphase and decreases thereafter. Because the level of p62 is constant throughout the cell cycle [Johnston and Sloboda, 1992: J. Cell Biol. 119:843-54] the decrease in phosphorylation of p62 observed after anaphase onset is most likely due to the action of a phosphatase. By examination of the relative amount of phosphorylated p62 which remained radiolabeled as a function of time using a standard in vitro phosphorylation assay, the activity of a phosphoprotein phosphatase capable of dephosphorylating p62 in the isolated mitotic apparatus was observed. To characterize the p62 phosphatase, okadaic acid and calyculin A were used to inhibit the dephosphorylation of p62 in vitro. It was found that specific concentrations of okadaic acid (50-500 nM) and of calyculin A (10-100 nM) were effective at inhibiting the dephosphorylation of p62 in vitro. Lower concentrations of either inhibitor had a negligible effect on dephosphorylation of p62. These data indicate the presence of phosphoprotein phosphatase type 1 activity associated with mitotic apparatus isolated from sea urchin embryos using the procedures described here. The implications of these findings relative to our understanding of the regulation of mitosis and cytokinesis are discussed. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 225-230 
    ISSN: 0886-1544
    Keywords: Weber's Law ; retinal ; retinal analogs ; photoreception ; alga ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The unicellular green alga Chlamydomonas reinhardtii maintains sensitivity of its phototaxis response (alignment of swimming direction along the axis of a light beam) over several orders of magnitude of light intensities. It is widely accepted that the rotation of the swimming cell provides temporal comparisons of light intensities via periodic contrast generated by its asymmetrically positioned refractile eyespot organelle. The cells also exhibit a second behavioral response to light called the photophobic (or stop) response, which is a brief cessation of swimming caused by a temporal change in light intensity. The cells are desensitized to photophobic stimuli by light exposure. Through comparative measurements of both responses, we explain the behavioral basis of the large dynamic range of phototaxis in terms of precise desensitization of the photophobic response. The basis of the explanation is that the flagellar beat changes which cause phototactic orientation are the residual of the photophobic response after desensitization (i.e., “mini-photophobic” reactions which cause brief reorienting motions without a full stop). This interpretation predicts quantitatively the dependence of the extent of desensitization on light intensity and the dependence of onset and maintenance of phototaxis on extent of desensitization. These predictions are tested and confirmed in this report. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 259-270 
    ISSN: 0886-1544
    Keywords: calsequestrin ; calreticulin ; sarcoplasmic reticulum ; skeletal muscle ; myofibril ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A major Ca2+-storing protein in endoplasmic reticulum (ER) of non-muscle cells is calreticulin (CR), which is considered to be functionally homologous to calsequestrin. Calsequestrin is a Ca2+-binding protein in sarcoplasmic reticulum (SR) of striated muscle, which stores Ca2+ during muscle relaxation. In order to investigate the expression and distribution of calsequestrin and calreticulin during skeletal muscle differentiation, cultured chick embryonic skeletal muscles were observed by immunofluorescence using anti-calsequestrin, anti-calreticulin, antidesmin, and anti-sarcomeric myosin antibodies and rhodamine-phalloidin. Within 6 hours in culture, myoblasts started to express desmin. Desmin-positive cells demonstrated the reticular staining of calreticulin, as did desmin-negative cells. Around fusion, calsequestrin and sarcomeric myosin started to appear in desmin-positive cells. The expression of calsequestrin slightly preceded that of sarcomeric myosin. As the myotubes matured, the fluorescent dots of calsequestrin increased and spread to the cell periphery along the myofibrils, while the reticular pattern of calreticulin gradually disappeared. Double labeling showed that calsequestrin colocalized with calreticulin. In mature myotubes, anti-calsequestrin staining demonstrated many dots along myofibrils, whereas calreticulin was barely seen except at the perinuclear region. These results suggest that the expression of calsequestrin and calreticulin are switched during skeletal muscle differentiation. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 291-300 
    ISSN: 0886-1544
    Keywords: endoplasmic reticulum ; DiOC6(3) ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Relationships among the endoplasmic reticulum (ER), microtubules, and bead movements on the cell surface were investigated in the thin peripheral region of A6 cells, a frog kidney cell line. ER tubules were often aligned with microtubules, as shown by double-labeling with DiOC6(3) and anti-tubulin in fixed cells. In living cells stained with DiOC6(3) and observed in time lapse, there were frequent extensions, but few retractions, of ER tubules. In addition, there was a steady retrograde (towards the cell center) movement of all of the ER at ∼0.3 μm/min. Since microtubules are often aligned with the ER, microtubules must also be moving retrogradely. By simultaneous imaging, it was found that the ER moves retrogradely at the same rate as aminated latex beads on the cell surface. This indicates that the mechanisms for ER and bead movement are closely related. Cytochalasin B stopped bead and ER movement in most of the cells, providing evidence that actin is involved in both retrograde movements. The ER retracted towards the cell center in nocodazole while both ER and microtubules retracted in taxol. Time lapse observations showed that for both drugs, the retraction of the ER is the result of retrograde movement in the absence of new ER extensions. Presumably, ER extensions do not occur in nocodazole because of the absence of microtubules, and do not occur in taxol because taxol-stabilized microtubules move retrogradely and there is no polymerization of new microtubule tracks for ER elongation. © 1994 Wiley-Liss, Inc.This Article is a US Government work and, as such, is in the public domain in the United States of America.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 108-116 
    ISSN: 0886-1544
    Keywords: smooth muscle ; fibroblasts ; lamellipodia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using a synthetic peptide mimicking the NH2-terminus of β-actin we have raised a monoclonal antibody specific for this cytoplasmic actin isoform. Specificity of the antibody was demonstrated by its labelling of the actin polypeptide only in tissues containing the β isoform, by its exclusive recognition of the synthetic β-actin peptide amongst those mimicking all six vertebrate isoactins, and by its selective recognition of the β-actin spot in two-dimensional electrophoresis gels of smooth muscle extracts. The antibody bound to actin filaments in both living and fixed fibroblasts where it labelled the stress fiber bundles and, more predominantly, the peripheral actin rich lamellipodia. The characteristics of the antibody indicate that it should serve as a useful tool for studying isoactin distribution and function. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 161-168 
    ISSN: 0886-1544
    Keywords: fluorescent nucleotide analogs ; methylanthraniloyl ATP ; anthraniloyl ATP ; Chlamydomonas ; axonemal mutants ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Substrate analogs are useful for studying the structures of active sites and for distinguishing between similar enzyme activities. Fluorescent ribose-modified ATP analogs were used to investigate the functional differences between dynein ATPases. These analogs reactivate (support the movement of) sea urchin sperm axonemes, yet they do not reactivate wild-type Chalmydomonas axonemes. Surprisingly, the analogs reactivate the axonemes of mutants completely missing the outer arm dyneins. Competition experiments using ATP and these analogs provide strong evidence that the analogs bind to all dynein active sites but fail to release a subset of dyneins from rigor. We suggest that this subset of Chlamydomonas outer arm dyneins unable to use the analogs remains in rigor in the presence of the analogs and paralyzes the axoneme. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 180-191 
    ISSN: 0886-1544
    Keywords: sliding movement ; 22S dynein ; Tetrahymena cilia ; dynein-track ; singlet microtubule ; ATP ; polarity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chlamydomonas and Tetrahymena axonemal dyneins have previously been found to bind to porcine brain microtubules to produce a microtubule-dynein complex. At appropriate microtubule:dynein concentration, microtubules in the complex became covered to saturation by dynein arms of the same polarity and at a spacing of 24 nm [Haimo et al., 1979; Haimo and Fenton, 1988; Haimo, 1989; Porter and Johnson, 1983a].In the present study, two different types of microtubule-dynein complexes (α-and β-complexes) were prepared from Tetrahymena ciliary 22S dynein and porcine brain tubulin. The characteristics of the adenosine triphosphate (ATP)-induced extrusion of microtubules from these complexes were analyzed, as a simple and direct in vitro assay for the ATP-induced extrusion of single microtubules. The α-complex prepared by adding dynein to microtubules showed an interrupted sliding movement, which would stop and start several times following the addition of ATP. In the β-complex, prepared by adding dynein bound to DEAE-tubulin to pre-assembled microtubules, microtubules became covered with dynein molecules whose orientation and binding were uniform with respect to microtubule polarity. The microtubules in the β-complex extruded at 12 μm/second following the addition of ATP. Dark-field and electron microscopy indicated that the extruded microtubules had undergone sliding on a dynein-track that had become detached from the complexes and had been absorbed onto the surface of the glass slide. At higher light intensity under a dark-field microscope, the dynein-track was seen to be composed of rows of dynein molecules arranged densely. The orientation of dynein molecules in rows appeared to be uniform considering the images of bound dynein in the β-complex under electron microscope. The higher sliding velocity of the microtubules on these dynein-tracks compared to that seen on slides coated at random with dynein [Vale and Toyoshima, 1988, 1989], may be due to more efficient force generation by this dense arrangement of dynein molecules with the same polarity on the tracks. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 234-247 
    ISSN: 0886-1544
    Keywords: microtubule-associated protein 2 ; neurons ; microtubule-associated proteins ; cytoskeleton ; dendrites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule-associated protein 2 (MAP-2) is an abundant component of the cytoskeleton present in dendrites and cell bodies of neurons of the CNS. To examine the biological function of MAP-2, two MAP-2 antisense (AS) oligonucleotides complementary to the 5′ region of the rat MAP-2 cDNA were added to rat primary embryonic day 17-18 (E17-18) cultured cortical neurons 24 h after plating and neurite outgrowth and morphology studied. The treatment of primary cortical cultures with either of the two MAP-2 AS oligonucleotides resulted in decreased MAP-2 and reduction in the number of neuritic processes relative to the control or MAP-2 sense-treated cultures. By immunostaining and light microscopy the AS-treated neurons appeared smaller, more rounded, and less intensely stained for MAP-2 than the untreated or the MAP-2 sense-treated cultures. By electron microscopy disorganized microtubules and a reduction in the number of microtubules within neurites of the AS-treated cultures were observed. We conclude that MAP-2 continues to be required for microtubule spacing and stability within neurites once they have formed. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 85
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    Cell Motility and the Cytoskeleton 27 (1994), S. 313-326 
    ISSN: 0886-1544
    Keywords: myosin II ; cardiac ; sarcomeric ; cytoplasmic myosin ; LMM ; Dd ; heterologous expression ; ConA ; receptor capping ; aggregation ; filament assembly region ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Manipulation of the single conventional myosin heavy chain (mhc) gene in Dictyostelium discoideum (Dd) has delineated an essential role for the filament-forming, or light meromyosin (LMM) domain of the myosin molecule in cyto-kinesis, development, and in the capping of cell surface receptors (see Spudich: Cell Regulation 1:1-11, 1989; Egelhoff et al.: Journal of Cell Biology, 112:677-688, 1991a). In order to assess the functional relationship between sarcomeric and cytoplasmic myosins, a chimeric gene encoding the Dd myosin head and subfragment 2 fused to rat β cardiac LMM was transfected into both wild-type and Dd mhc null cells. Chimeric myosin was organized into dense cortical patches in the cytoplasm of both wild-type and Dd mhc null cells. Although null cells expressing chimeric mhc at ∼10% of Dd mhc levels were unable to grow in shaking suspension or to complete development, chimeric myosin was able to rescue capping of cell surface receptors, to associate with filamentous actin, and to localize to the correct subcellular position during aggregation. Deletion of 29 amino acids in the rod corresponding to a previously defined filament assembly competent region eliminated the cortical patches and the posterior localization during chemotaxis. Taken together, these observations suggest that sarcomeric and cytoplasmic myosin rods are functionally interchangeable in several aspects of nonmuscle motility. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 27 (1994), S. 337-349 
    ISSN: 0886-1544
    Keywords: microtubules ; glutamylation ; Paramecium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubular networks are extensively developped in many ciliate species. In several of them, we investigate the occurrence of the post-translational glutamylation of tubulin [Eddé et al., 1990: Science 247:82-85; Eddé et al., 1991: J. Cell. Biochem. 46:134-142] using as a probe for such modified tubulin, the monoclonal antibody GT335 [Wolff et al., 1992: Eur. J. Cell Biol. 59:425-432]. Results obtained in Paramecium strongly suggest that both axonemal and cytoplasmic tubulin are glutamylated. As in the vertebrate brain tubulin so far tested, the GT335 epitope is located at the carboxy-terminal fragment of cytoplasmic tubulin removed by subtilisin treatment. Immunoblotting and immunofluorescence experiments reveal that, unlike tubulin acetylation, glutamylation is not restricted to cold-resistant microtubules. In addition, immunofluorescence studies performed on dividing cells show that glutamylation takes place soon after the polymerization of microtubules.Finally, glutamylated tubulin is also detected in the ciliate species Euplotes, Tetrahymena, and Paraurostyla. Together with results obtained on flagellate species, this suggests that tubulin glutamylation came out early in the course of eukaryotic evolution and has been widely exploited in various cellular strategies. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 25-33 
    ISSN: 0886-1544
    Keywords: actin structures ; vinculin ; focal contacts ; spontaneous metastasis ; extracellular pH ; cell motility ; malignancy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have studied the organisation of the actin cytoskeleton in three related rat sarcoma cell populations of differing malignancy. They were derived by neoplastic progression from a population which had transformed spontaneously in vitro, and were distinguished by their ability to give rise to reproducibly different numbers of metastases, ranging from 10% to 80% of the animals inoculated. We found characteristic differences in the arrangement of the actin cytoskeleton. Confocal three-dimensional microscopy showed that nearly all of the least malignant population contained conspicuous actin stress fibres lying in the lower part of the cell parallel to the substratum and no other actin structures. Actin in the intermediate population was typically situated in a diffuse layer underlying the whole plasma membrane, in which no fibres could be seen. Two thirds of the most malignant population consisted of more rounded cells filled with a three-dimensional network of fine oblique actin fibres. There were focal contacts in all these cells; their area showed a regular decrease from 1.3 μm2 to 0.4 μm2. The differences in actin distribution were accompanied by differences in motility, which increased as malignancy increased. When individual cells were fixed after they had been tracked by time-lapse, their cytoskeleton type correlated with the speed at which they had moved. All these differences were enhanced at low pH. These findings point to the possibility that the three-dimensional network of fine actin fibres in acid culture could be a measure of the malignant potential of transformed cells in vitro. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 28 (1994), S. 108-118 
    ISSN: 0886-1544
    Keywords: Xenopus MAPs ; microtubule cycling ; 230 kDa heat-stable MAP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe the purification of microtubule proteins from Xenopus egg extracts by temperature-dependent assembly and disassembly in the presence of dimethyl sulfoxide and identify a number of presumptive microtubule-associated proteins (MAPs). One of these proteins has a molecular weight of 230 kDa and is immunologically related to HeLa MAP4. We show that this MAP is heat stable and phosphorylated, and that it promotes elongation of microtubules from axonemes. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 143-154 
    ISSN: 0886-1544
    Keywords: microtubule-associated proteins ; microtubule nucleation ; tubulin ; cytoskeleton ; axon ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The neuronal microtubule-associated protein tau has been implicated in the development of axonal morphology including the organization of microtubules into a uniformly oriented array of microtubules commonly referred to as “bundle.” Determination of the functional organization of tau has revealed that regions of tau protein which flank the microtubule-binding domain affect the bundling of microtubules in vitro with a microtubule-binding fragment of tau being most effective [Brandt and Lee, 1993: J. Biol. Chem. 268:3414-3419]. In order to study the relation of microtubule bundles that form in vitro to those observed in the axon, we determined the orientation of individual microtubules in bundles and the effects of bundling on microtubule assembly and stability in cell-free assembly reactions. Here we report that bundles induced by a microtubule-binding fragment of tau contain randomly oriented microtubules as determined by using the difference in growth rates at microtubule plus and minus ends. We demonstrate that in vitro bundling increases microtubule growth (about 30%), stabilizes microtubules against dilution- and cold-induced disassembly, and allows microtubule nucleation despite the absence of a tau region which has previously been shown to be required for tau-dependent microtubule nucleation. We conclude that conditions that stabilize microtubules can lead to bundle formation and allow microtubule assembly by a mechanism different from that employed by microtubule-associated proteins. The data also support the view that additional mechanisms besides the action of tau and tubulin exist in order to organize microtubules in the axon. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 205-212 
    ISSN: 0886-1544
    Keywords: microtubule motor ; organelle transport ; vesicle transport ; liposomes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic dynein is the putative motor protein for retrograde organelle transport along microtubules in cells and, thus, must be capable of binding to organelle membranes. Such an attachment may occur via receptor proteins or through a direct interaction of dynein with the membrane phospholipids. We show here that cytoplasmic dynein-synaptic membrane binding does not require a receptor protein and that this binding is mediated by an electrostatic interaction with acidic phospholipids. The properties of cytoplasmic dynein binding to NaOH-extracted synaptic membranes are not significantly affected when those membranes are treated with trypsin to digest endogenous integral membrane proteins. Moreover, purified cytoplasmic dynein is capable of binding to liposomes composed of pure phospholipids. Dynein binds to liposomes with a profile remarkably similar to that of dynein binding to native membranes. Dynein-liposome binding is dependent upon the presence of acidic phospholipids and is disrupted by NaCl. Thus, these studies suggest that electrostatic interactions can effect dynein-membrane binding. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 256-264 
    ISSN: 0886-1544
    Keywords: taxol ; cytochalasin ; polarity ; microtubule-associated proteins ; lammelopodia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Insect Sf9 cells usually elaborate a highly characteristic single process when infected with a baculovirus encoding recombinant human tau. The processes are unbranched, of uniform caliber, and contain bundles of microtubules. Because taxol treatment alone does not induce process outgrowth in these cells, it is believed that tau confers properties on microtubules that permits the conversion of microtubule assembly into the formation of processes. Here we have analyzed the reorganization of both actin filaments and microtubules during process initiation. A zone of organelle exclusion representing the focal reorganization of actin at one pole of the cell anticipated process emergence. A relationship between actin organization and process emergence was also suggested by a shift from single to multiple process formation after treatment with cytochalasin D. The rate of process elongation doubled after cytochalasin treatment of tau-expressing cells. The increase in rate was due to the inhibition of the growth arrest phases which occur in the absence of cytochalasin. In contrast, Sf9 cells treated with cytochalasin after more than 20 h of tau expression were relatively resistant to the drug's effects. We conclude that actin and microtubules are specifically reorganized during tau-induced process outgrowth and that a dynamic relationship between actin filaments and microtubules effects process formation. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 285-302 
    ISSN: 0886-1544
    Keywords: PMN ; 3-D video-microscopy ; quasielastic laser light scattering ; chemotaxis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The locomotion of human polymorphonuclear leukocytes (PMNs) was studied with two complementary methods: Three-dimensional shapes were reconstructed from time series of optical sectioning microscopy using differential interference contrast (DIC) optics, and the diffusion of cytoplasm granules within individual cells was measured using quasielastic laser light scattering (QELS). The three-dimensional cell edges outlined in the optical sections were analyzed qualitatively in time-lapse film strips and quantitatively from morphometry. The fastest locomotion occurred in chemotactic gradient with cell velocity that oscillated between 10 and 30 μm/min with a period of 50-55 seconds. Within the periodic bursts of speed, a fibroblast-like locomotory cycle was observed, with leading lamella extended and contacts formed with the substrate surface, followed by rapid motion of the cell body and nucleus over the immobile contacts. Consistent with this apparent staged motion, correlation analysis revealed a phase lag of 2-3 seconds in velocities between the bottom (ventral) and the top layers of the cell. In addition there was a tendency to a lower cell profile at times of higher velocity. The diffusion of natural cytoplasmic granules within resting PMNs was not affected by cytoskeleton disrupting drugs. During the stage of most rapid motion, when cytoplasmic streaming could be seen, diffusion of the granules decreased two- to 2.5-fold, and then returned to resting levels. These observations suggest that PMN locomotion consists of extensions near the surface to form forward contacts and then stiffening or possibly contraction of the cytoskeleton when the body of the cell is moved forward.Three-dimensional movies of PMN cells are included in the video supplement. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 28 (1994), S. 359-359 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 28 (1994), S. 346-358 
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; actin ; alpha-actinin ; actin polymerization ; assembly ; disassembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Listeria monocytogenes can penetrate and multiply within a variety of cell types, including the PtK2 kidney epithelial line. Once released within the cytoplasm, L. monocytogenes acquires the capacity for rapid movement through the host cell [Dabiri et al., 1990: Proc. Natl. Acad. Sci. 87:6068-6072]. In the process, actin monomers are inserted in proximity to one end of the bacterium, forming a column or tail of actin filaments [Sanger et al., 1992: Infect. Immun. 60:3609-3619]. The rate of new actin filament growth correlates closely with the speed of bacterial migration. In this study we have used fluorescently labeled actin and alpha-actinin to monitor the movement and turnover rate of actin and alpha-actinin molecules in the tails. The half-lives of the actin and alpha-actinin present in the tails are approximately the same: actin, 58.7 sec; alpha-actinin, 55.3 sec. The half-life of alpha-actinin surrounding a dividing bacterium was 30 sec, whereas its half-life in the tails that formed behind the two daughter cells was about 20-30% longer. We discovered that the speeds of the bacteria are not constant, but show aperiodic episodes of decreased and increased speeds. There is a fluctuation also in the intensities of the fluorescent probes at the bacterium/tail interface, implying that there is a fluctuation in the number of actin filaments forming there. There was no strong correlation, however, between these fluctuating intensities and changes in speed of the bacteria. These measurements suggest that while actin polymerization at the bacterial surface is coupled to the movement of the bacterium, the periodic changes in intracellular motility are not a simple function of the number of actin filaments nucleating at the bacterial surfaces. © 1994 Wiley-Liss, Inc.
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  • 96
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    Keywords: actin filaments ; cytokinesis ; phagocytosis ; contractile vacuole ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dictyostelium discoideum amoebae possess eight different actin crosslinking proteins. Immunofluorescence microscopy has been employed in this study to investigate the intracellular localization of two of these proteins, α-actinin and the 30 kD actin-bundling protein, to investigate whether they are redundant, or alternatively, make distinct contributions to cell structure and movement. The 30 kD protein is concentrated in the cleavage furrow of dividing cells, while enhanced staining for α-actinin is not apparent in this region. By contrast, α-actinin is concentrated around the contractile vacuole, while the 30 kD protein is not preferentially localized in the area of this organelle. Association of α-actinin with the contractile vacuole was confirmed by colocalization with calmodulin, a marker of this organelle. There are temporal differences in the localization of the 30 kD protein and α-actinin during phagocytosis. The 30 kD protein is localized in the phagocytic cup, but disassociates from phagosomes soon after internalization [Furukawa et al., 1992: Protoplasma 169: 18-27]. α-actinin enters the phagocytic cup after the 30 kD protein, and remains associated with the phagosome after the 30 kD protein has disassociated. These results support the hypothesis that α-actinin and the 30 kD protein play distinct roles in cell structure and movement in Dictyostelium. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 117-130 
    ISSN: 0886-1544
    Keywords: microtubules ; tau ; microfilament-associated proteins ; actin filaments ; growth cones ; antisense oligonucleotides ; cell culture ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report here a novel intracellular localization and function of Tau proteins in cultured cerebellar neurons. Immunofluorescence staining of detergent-extracted cytoskeletons with antibodies specific for Tau proteins revealed intense labeling of growth cone microtubules. Besides, suppression of Tau by antisense oligonucleotide treatment results in the complete disappearance of antigen 13H9, a specific growth cone component with properties of microfilament- and microtubule-associated protein [Goslin et al., 1989: J. Cell Biol. 109:1621-1631], from its normal intracellular location. This phenomenon is unique to neurite-bearing cells, is not associated with the disappearance of microtubules from growth cones, and is not reversed by taxol, a microtubule-stabilizing agent. In addition, Tau-suppressed neurons display a significant reduction in growth cone area and fillopodial number; on the contrary, fillopodial length increases significantly. The alterations in growth cone morphology are accompanied by considerable changes in the phalloidin staining of assembled actin. Taken together, the present results suggest that in developing neurons Tau proteins participate in mediating interactions between elements of the growth cone cytoskeleton important for maintaining the normal structural organization of this neuritic domain. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 167-176 
    ISSN: 0886-1544
    Keywords: NuMA ; spindle ; nuclear matrix ; core filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using a monoclonal antibody 2D3 generated against a kinetochore-enriched human chromosome preparation, we identified a high molecular mass protein with nuclear staining in interphase and polar staining of the pericentriolar region in the mitotic spindle. Initially termed centrophilin, this protein associates with the minus-ends of spindle microtubules (MT) and appears to be important in spindle organization [Tousson et al., 1991: J. Cell Biol. 112:427-440]. Comparison of a partial cDNA sequence obtained for centrophilin with the full length cDNA sequence of nuclear mitotic apparatus protein (NuMA) [Compton et al., 1992: J. Cell Biol. 116:1395-1408; Yang et al., 1992: J. Cell Biol. 116:1303-1317] has indicated that NuMA and centrophilin are the same protein. Using a polyclonal NuMA antibody, we have provided further evidence that NuMA exists as iso-forms as shown by peptide mapping and immunoblots. Sequential fractionation experiments along with immunofluorescence, immunoblotting, and EM immunogold labeling have demonstrated that NuMA isoforms are novel components of nuclear core filaments. Thus, NuMA, a long coiled-coil protein, appears to have dual functions in interphase and mitosis during the cell cycle. In interphase, NuMA likely plays a structural role in the nucleoskeleton that may be important in nuclear organization and functions, whereas in mitosis, NuMA appears to be associated with spindle MT organization and chromosome positioning. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 186-194 
    ISSN: 0886-1544
    Keywords: sperm motility ; intermittent swimming ; Arenicola marina ; annelida ; polychaeta ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Motile spermatozoa of the polychaete Arenicola marina were observed to swim intermittently. On the basis of the behaviour of the flagellum, the quiescent periods can be classified into two main types. The first are those in which, although the generation of the flagellar wave appears to be initiated, its passage down the axoneme appears blocked. This results in the formation of an acute bend (of approximately 2.65 rad) in the proximal region of the flagellum with the remainder of the axoneme remaining straight. These have been termed Type I quiescent periods and are very similar to the “cane-shaped” configuration which has been described in the spermatozoa of some sea urchins. Sperm may also enter a Type II quiescent period, in which both the propagation and the generation of flagellar waves appears blocked. The flagellum of such sperm appears straight or slightly curved and they can remain in this configuration for several minutes. With increased intensity and duration of irradiation, the length of time spent in Type II quiescent period was increased significantly. Both types of quiescent period were (1) reduced in duration and frequency by deletion of calcium from artificial sea water (ASW); (2) either abolished or reduced in duration by the addition of 1 mM cadmium chloride to ASW. In addition, flagellar waveforms very similar to those displayed by spermatozoa in Type I quiescent periods could be induced (if only for a short time) by the addition of the divalent cation ionophore A23187 to ASW. It is suggested that this type of behaviour may be induced following an influx of calcium into the intraflagellar compartment of spermatozoa and that this may be mediated by certain intensities and wavelengths of light. © 1994 Wiley-Liss, Inc.
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    Cell Motility and the Cytoskeleton 29 (1994), S. 231-240 
    ISSN: 0886-1544
    Keywords: cell motility ; scanning acoustic microscopy ; domains of motility ; mechanical properties of the cell ; neoplastic cells ; metastasis ; malignancy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning acoustic microscopy (SAM) observes all mechanical properties of living cells. Subtraction of the SAM images (SubSAM) of live cells was developed as a method for investigating minimal changes in cellular topography and elasticity. The image formation in the SubSAM takes into account the motion of cell mass as well as the changes of tension. High spatial and temporal resolution of the SubSAM revealed the structure of motile processes that develops at increasing time intervals, thus allowing the arising complexity of motion to be registered and investigated. Independent spots of activity emerge on a quiescent background as motility domains; they may change position, divide, merge, or disappear after a long time interval. In addition, zones of quiescence were identified over central parts of cytoplasmic lamellae. Nonmalignant (Ep: tadpole epidermal cells, XTH2: endothelial cells from tadpole hearts, 3T3 cells) and neoplastic cells (K2 cells of rat fibrosarcoma, A870N cells selected from K2) were investigated with the SubSAM. Three types of domains of subcellular cytoplasmic motility were identified in time series of two-dimensional SubSAM images in normal and neoplastic cells. Of them only the wave-like domain is self-evident, being derived from ruffling and protruding activity at the cell margin. Two other domains wait for detailed analysis. The oscillating domain is a visualization of tension within the cell(s), and the nucleating domain indicates intracellular processes possibly preceding locomotion. Differences in motile domains were found between low K2 and high A870N metastatic cells. The dynamics of motility domains of the A870N cells resembled that of the highly motile Ep cells. Cell morphotype and motile activity of the A870N cells are significantly influenced by the pH of the medium. It became evident that identification of the otherwise invisible motile domains in living cells by SubSAM opens a new approach to a characterization of cell motility in vitro and to an understanding of early cellular reactions to various stimuli. © 1994 Wiley-Liss, Inc.
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