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  • Inorganic Chemistry  (3,506)
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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
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    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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  • 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
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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
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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
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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
    Repository Name: AquaDocs
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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
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
    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
    Repository Name: AquaDocs
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    Format: application/pdf
    Format: application/pdf
    Format: 100-105
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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
    Repository Name: AquaDocs
    Type: book_section
    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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    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
    Repository Name: AquaDocs
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    Format: A-3.1-A-3.2
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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
    Repository Name: AquaDocs
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    Format: application/pdf
    Format: D-4.1-D-4.4
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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
    Repository Name: AquaDocs
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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: 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
    Format: application/pdf
    Format: 35-42
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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
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 35
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 371-385 
    ISSN: 0886-1544
    Keywords: microtubules ; dynein ; tubulin ; cilia and flagella ; microtubule associated proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dynein, obtained from axonemes of Chlamydomonas, binds by both its A and B ends to microtubules assembled from twice cycled (2 ×) and purified (6S) brain tubulin as well as to microtubules in native spindles, thereby inducing microtubule crossbridging. The two ends of the dynein arm exhibit distinct binding characteristics for the different microtubule preparations. Greater than 99% of the dynein arms are bound exclusively by their B ends to microtubules assembled from 6S tubulin in the presence of dynein and decorated to saturation. In contrast, greater than 80% of the dynein arms are bound by both their A and B ends to and, therefore, crossbridge 6S microtubules that are only partially dynein decorated. Binding of the A end of the dynein arm to saturated 6S microtubules can be enhanced by destabilizing the binding of the B end upon addition of ATP and vanadate. These observations suggest that Chlamydomonas dynein arms can bind by their A ends to microtubules assembled from 6S tubulin only when the B ends of the arms either are not bound or are bound but do not occupy all available dynein binding sites. Dynein exhibits a slight preference for binding by its A end to microtubules assembled from 2 × tubulin and containing microtubule associated proteins (MAPs). Approximately 90% of the dynein arms crossbridge adjacent 2 × microtubles that are only partially decorated. But as saturation of these microtubules with dynein is approached, the majority of the arms are bound solely by their A ends, while a smaller percentage are bound by their B ends or by both their A and B ends. These studies indicate that the type of microtubule as well as the degree of saturation of the microtubule with dynein can determine whether microtubule crossbridging occurs.
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  • 36
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 431-441 
    ISSN: 0886-1544
    Keywords: dynein ; chromatophores ; permeabilization ; melanosomes ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Teleost chromatophores are filled with individual pigment granules that rapidly aggregate to the cell center or become dispersed throughout the cytoplasm in response to environmental stimuli. Microtubules appear to be required for pigment aggregation (movement toward the cell center), and recent findings have suggested that a dynein-like ATPase may participate in force production. Based on previous studies, however, it has been argued that pigment aggregation does not require energy directly, a view that supports the involvement of an elastic component in granule movement. To examine this point further, we have reinvestigated the energy requirements for pigment aggregation using both intact cells and detergent-permeabilized cell models of Fundulus melanophores. Poisons of oxidative phosphorylation, namely, 2,4 dinitrophenol and NaCN, reversibly inhibit melanosome aggregation in response to adrenaline. Inhibition of movement results directly from depletion of intracellular ATP, since pigment translocation can be reactivated in permeabilized cells by the addition of exogenous ATP to the lysis buffer. Non-hydrolyzable analogues, including β,γ-imidoadenosine-5′-triphosphate (AMPPNP), β,γ-methylene adenosine-5′-triphosphate (AMPPCP), and ATPγS, will not substitute for ATP in reactivation of movement. Similarly, other nucleotides such as ADP, AMP, GTP, CTP, and ITP, have limited ability to support melanosome aggregation in metabolically poisoned cells subjected to detergent lysis. ATP itself has no effect on intact cells. These results indicate that melanosome aggregation is ATP-dependent and energy-driven, and are consistent with a role for a force-transducing ATPase in particle movement.
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  • 37
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 38
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 41-55 
    ISSN: 0886-1544
    Keywords: Leptodiscinae ; Dinoflagellates ; contractility ; non-actin filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Leptodiscinae, a group of marine Dinoflagellates, are good material for the study of contraction though they cannot be collected in abundance. Their cell bodies are flattened anteroposteriorly (Leptodiscus, Leptophyllus, and Leptospathium) and are able to contract suddenly when the surrounding water is disturbed.Electron microscopical observations have shown that the structures responsible for the contraction consist of a layer of parallel filaments located beneath the cell membrane of some specialized parts of the body. These filaments seem to be nonactin (NAF) because of their diameter (2.5-3 nm) and because they are not decorated by heavy meromyosin (HMM). They appear helically coiled and doubly twisted, and form tubular structures when contracted.
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  • 39
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 25-27 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 40
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 183-196 
    ISSN: 0886-1544
    Keywords: tubulin ; assembly ; mitotic apparatus ; bimane ; fluorescence microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent derivatives of cellular proteins that retain their native characteristics have become useful probes to investigate the dynamics of specific cytoskeletal proteins. In the experiments reported here, a previously characterized fluorescent derivative of tubulin, bimane-tubulin [Wadsworth and Sloboda, 1982a], was used to investigate microtubule assembly in vitro. The results demonstrate that bimanetubulin was competent to assemble onto a variety of organizing centers in vitro, including microtubule organizing centers (MTOCs) present in homogenates of sea urchin eggs, isolated mitotic apparatuses (MAs), and lysed mitotic cells. When homogenates of fertilized sea urchin eggs containing MTOCs were incubated with bimane-tubulin at 37°C, discrete areas of linear fluorescence were observed. Only diffuse fluorescence was observed when calcium or colchicine was added to the homogenate or if the temperature was maintained at 0°C. Negative-stain electron microscopy of the fluorescent arrays revealed morphologically normal microtubules radiating from electron dense regions. When mitotic spindles, isolated in glycerol containing buffers and therefore cold stable, were incubated with bimane-tubulin, linear fluorescence was observed emanating from the spindle poles but not from the region occupied by the kinetochores. MAs incubated with bimane-labeled bovine serum albumin or bimane-labeled microtubule-associated proteins showed only diffuse fluorescence. However, when mitotic cells which were hypotonically lysed in the absence of detergents or microtubule stabilizing solvents, were perfused with bimane-tubulin intense fluorescence was observed in the asters and throughout the spindle. Two experiments suggested that the fluorescence observed in the results outlined above was due to the assembly of normal microtubules from the fluorescent subunits. First, the observed fluorescence was sensitive to cold temperataure, which is known to disassemble microtubules. Second, when the isolated, fluorescent MAs were examined by thin section electron microscopy, microtubules of normal diameter were seen. No aggregated material appeared associated with the walls of the microtubules, which might have been expected if the fluorescent protein was nonspecifically adsorbed to the microtubules. The results of these experiments demonstrate that isolated, stabilized MAs support the growth of new microtubules from the spindle poles while labile spindles, present in lysed cells, incorporate fluorescent tubulin throughout the spindle and asters. The significance of these results for hypotheses concerning microtubule assembly and disassembly during mitosis is discussed.
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  • 41
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 7-23 
    ISSN: 0886-1544
    Keywords: axoplasm ; elastic modulus ; viscosity ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A magnetic sphere viscoelastometer has been developed to peform rheological experiments in living axoplasm of Loligo pealei. The technique includes the use of a calibrated magnetic sphere viscoelastometer on surgically implanted ferro-magnetic spheres in intact squid giant axons. The axoplasm was discerned to be “living” by the biological criterion of tubulovesicular organelle motility, which was observed before and after experimentation. From these in vivo experiments, new structural characteristics of the axoplasm have been identified. First, analysis of magnetic sphere trajectories has shown the axoplasm to be a complex viscoelastic fluid. Directional experimentation showed that this material is structurally anisotropic, with a greater elastic modulus in the direction parallel to the axon long axis. Second, both magnetic sphere and in vivo capillary experiments suggested that the axoplasm is tenaciously anchored to the axolemma. Third, it was found that axoplasm could be modelled as a linear viscoelastic material in the low shear rate range of 0.0001 to 0.004 s-1. The simplest mechanical model incorporating the discovered properties of the material in this range is Burger's model.
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  • 42
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 43
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 103-119 
    ISSN: 0886-1544
    Keywords: cilia ; metachrony ; serum immunoglobulins ; IgM ; Mytilus edulis ; cystic fibrosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human IgM and a bovine, IgM-enriched serum fraction isolated from normal adult serum at concentrations of 0.25-1 mg/ml protein induced a pronounced increase in the metachronal wavelength of the lateral (L) cilia of the sea mussel Mytilus edulis without altering their beat frequency. This change in activity was indistinguishable from that induced by 50% adult human or bovine serum. At protein concentrations ranging from 1-9 mg/ml, human IgG or a bovine, IgG-enriched serum fraction had no or little effect on the activity of the L cilia. Similarly, neither monomeric (8S) human IgM (0.25 mg/ml) nor monospecific pentameric IgM (1 mg/ml) isolated from Waldenström's macroglobulinemia patients altered the metachrony of the L cilia. Indirect immunofluorescence demonstrated that both bovine and human IgM became attached almost exclusively to the L cilia, while very little bovine or human IgG was found to associate with these cilia.The results of this study suggest that serum IgM specifically binds to the L cilia of Mytilus in an antigen-antibody manner and agglutinates adjacent cilia into blocks or bundles, thereby increasing the coupling between cilia. As a result, the wavelength of the metachronal coordination is increased. The origin of these ciliary antibodies and their significance to ciliary bioassays used to monitor serum for the detection of cystic fibrosis are discussed.
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  • 44
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 417-430 
    ISSN: 0886-1544
    Keywords: flagella ; image analysis ; microcomputer ; motility ; parameter estimation ; Simplex method ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Parameters to describe flagellar bending patterns can be obtained by a microcomputer procedure that uses a set of parameters to synthesize model bending patterns, compares the model bending patterns with digitized and filtered data from flagellar photographs, and uses the Simplex method to vary the parameters until a solution with minimum root mean square differences between the model and the data is found. Parameters for Chlamydomonas bending patterns have been obtained from comparison of shear angle curves for the model and the data. To avoid the determination of the orientation of the basal end of the flagellum, which is required for calculation of shear angles, parameters for sperm flagella have been obtained by comparison of curves of curvature as a function of length for the model and for the data. A constant curvature model, modified from that originally used for Chlamydomonas flagella, has been used for obtaining parameters from sperm flagella, but the methods can be applied using other models for synthesizing the model bending patterns.
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  • 45
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 77-87 
    ISSN: 0886-1544
    Keywords: Chlamydomonas ; flagella ; cell surface ; adhesion ; glycoproteins ; iodination ; lactoperoxidase ; Iodogen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Chlamydomonas flagellar surface exhibits interesting adhesive properties that are associated with flagellar surface motility. This dynamic surface property can be exhibited as the binding and movement of small polystyrene microspheres or as the interaction of the flagellar surface with a solid substrate followed by whole cell locomotion, termed “gliding.” In order to identify flagellar surface proteins that mediate substrate interaction during flagellar surface motility, two immobilized iodination systems were employed that mimic the conditions for flagellar surface motility: small polystyrene microspheres derivatized with lactoperoxidase, and large glass beads derivatized with Iodogen. Use of these iodination conditions resulted in preferential iodination of a high-molecular-weight glycoprotein with apparent molecular weight of 300,000-350,000. These results suggest this glycoprotein as a major candidate for the surface-exposed adhesive component that directly interacts with the substrate and couples the substrate to a system of force transduction presumed to be located within the flagellum.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 129-135 
    ISSN: 0886-1544
    Keywords: amoeboid motion ; chemoattractants ; chemotaxis ; Dictyostelium ; filopodia ; folic acid ; pterins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Living vegetative D. discoideum amoebae were studied to determine whether their filopodia respond to folic acid, a chemoattractant for these cells. Exponentially growing amoebae (ca. 10 μm diameter) exhibit 5-30 μm long filopodia; at stationary phase, aggregation competent amoebae have numerous multibranched filopodia up to 100 μm long. Folic acid was observed to stimulate production, elongation, and branching of filopodia with its effects progressively changing as the amoebae approach aggregation. Filopodial construction was also found to be dependent upon Mg2+ levels. The significance of these results is discussed with respect to progressive changes within the vegetative phase as well as to the mechanisms of amoeboid movement, pseudopodial activity, and chemotaxis.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 29-40 
    ISSN: 0886-1544
    Keywords: microfilaments ; microtubules ; contraction ; collagen gel ; fibroblasts ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In vitro models have been developed recently to study the ability of fibroblasts to generate tensile force within collagen gels. The present study was initiated to assess the role of the cytoskeleton in the cell shape changes and force generation in one such model system. Porcine periodontal ligament fibroblasts (PPLF) were cultured within three-dimensional collagen gels attached to glass coverslips. Fluorescence microscopy, using nitrobenzooxadizole (NBD)-phallacidin labeling for microfilaments and tubulin antibody staining for microtubules, was combined with phase and Nomarski optics to determine the intra- and extracellular architecture of the cells and collagen fibers. Samples were observed from 30 minutes to 24 hours after initiation of cell attachment. During attachment and spreading, NBD-phallacidin staining changed dramatically until large microfilament bundles became prominent. Collagen fiber alignment, compaction, and finally tearing from the coverslip occurred during this time. After release of tension, microfilament bundles were no longer evident. The change in microtubule distribution during these processes was less dramatic, appearing to follow the change in cell shape. These results indicate that microfilaments play an essential role in generating force to align and compact collagen, while microtubules may have a secondary role only.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 241-247 
    ISSN: 0886-1544
    Keywords: cytoskeleton ; centrosome ; tonofilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present observations on the relative location of the centriole and keratin filament cap in motile PtK1 cells. Subconfluent cells were double labeled with anticentriole and antikeratin sera. These preparations revealed that the centriole is separate from, but neighboring, the keratin filament cap. Serial ultrathin sections confirm this observation. These observations are consistent with the idea that the microtubule organizing center and intermediate filament distribution center are not identical or concentric in PtK1 cells.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 169-181 
    ISSN: 0886-1544
    Keywords: cytoskeleton ; motility ; cell spreading ; epithelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reorganization of intermediate filaments during cell spreading is examined by immunofluorescence, electron microscopy, and time-lapse video microscopy. A juxtanuclear cap, believed to correspond to the intermediate filament distribution center, was observed to be spatially related to the organization of the intermediate filament network as cells spread. A keratin cap was observed, which appeared spontaneously in motile PtK1 cells. Cap formation may be a consequence of retraction of intermediate filaments from the cytoplasm as cells move. The position of this juxtanuclear cap is related to the direction of movement, located on the side of the nucleus near the advancing edge of the cell. As the cell spreads, the cap disappears as the keratin filament network returns to the cytoplasm. Evidence presented here is consistent with the hypothesis that the distribution center mediates keratin filament organization during cell shape change.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 227-229 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984), S. 269-281 
    ISSN: 0886-1544
    Keywords: microtubules ; microfilaments ; filopodia ; cell spreading ; coelomocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sea urchin coelomocytes were used as a model system to investigate the distribution and role of microtubules and microfilaments in cell spreading and filopodial formation. By using immunoblot characterized antisera to tubulin and actin coupled with immunofluorescence techniques, cellular protrusions were seen to contain actin filaments but no microtubules. Cells depleted of MT's by cold and colcemid treatments could attach, spread, and transform to the filopodial morphology normally.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 297-303 
    ISSN: 0886-1544
    Keywords: exocytosis ; chromaffin cells ; vesicle release ; light microscope ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Cultured bovine adrenal medullary chromaffin cells were stimulated with the secretogogues Ba2+ or carbamyl choline plus Ca2+. With video-enhanced contrast, differential interference contrast microscopy, small vesicles were found to appear on the cell surface during stimulation. The structures were of lower refractive index than the cytoplasm, and their appearance required several tenths of a second. The vesicles are thought to correspond to omega figures seen with electron microscopy due to exocytosis. Many of the structures disappeared within a few seconds, but some appeared to coalesce into larger structures. The large structures may lead to the vacuoles that have been demonstrated to be present following stimulation. The nature of the cellular elements responsible for the vesicle which appeared on the surface was not found with either differential interference or interference reflection microscopy. The simplest explanation is that the refractive index of the elements is similar to that of the cell, and therefore the elements cannot be seen.
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  • 53
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    Keywords: fibroblast ; permeabilized cell model ; Ca2+-dependent contraction ; calmodulin ; phosphorylation ; myosin light chain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Human lung fibroblast MRC-5 cells treated with Triton X-100 (MRC-5 cell models) were able to contract in the presence of MgATP and Ca2+ of more than 1 μM. Immunofluorescence microscopy with antibodies to actin and myosin 20,000-dalton (20 Kd) light chain revealed that stress fibers were prominent in MRC-5 cell models. Use of a fluorescent actin probe, 7-nitrobenz-2-oxa-1,3-diazole-phallacidin permitted visualization of contraction of the stress fibers in the presence of MgATP and Ca2+. Of the proteins in MRC-5 cell models, only a myosin 20 Kd light chain was phosphorylated in a Ca2+-dependent manner. This Ca2+-dependent phosphorylation of the 20 Kd light chain closely corresponded with the contraction of MRC-5 cell models: 1) Both phosphorylation of the 20 Kd light chain and contraction of MRC-5 cell models were inhibited by calmodulin antagonists such as N-(6-aminohexyl)5-chloro-1-napthalene sulfonamide. 2) The threshold Ca2+ concentration for phosphorylation of the 20 Kd light chain was similar to that for contraction of MRC-5 cell models. Both were lowered by exogenous calmodulin in a concentration-dependent manner. 3) The 20 Kd light chain was thiophosphorylated by incubation of MRC-5 cell models with an ATP analogue, adenosine 5′-0-(3-thiotriphosphate) only in the presence of Ca2+. After this treatment, MRC-5 cell models lost the Ca2+-dependence for contraction. These results indicate that Ca2+-calmodulin-dependent phosphorylation of myosin 20 Kd light chain is required for contraction of MRC-5 cell models.
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    Cell Motility and the Cytoskeleton 4 (1984) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984), S. 197-213 
    ISSN: 0886-1544
    Keywords: gelation ; actin ; filamin ; cytoplasm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: We have compared the meniscus depletion assay and falling ball viscometry, two means of assessing the extent of gelation in actin-based systems using mixtures of actin and the actin-binding protein filamin. We examined the effect of varying the concentrations of actin and filamin in both assays. The interaction of actin and filamin was detected only above a threshold concentration of filamin. This threshold concentration was lower for falling ball viscometry than for the meniscus depletion assay at equal actin concentrations. At constant concentrations of filamin, an increase in actin concentration caused an increase in apparent viscosity measured by the falling ball assay, but a decrease in sedimentability detected by the meniscus depletion assay. The rate of sedimentation of actin was dependent on the molar ratio of actin to filamin. At each molar ratio, the sedimentation of actin was not dependent on the specific concentrations of actin and filamin used. The apparent viscosity was dependent on both the molar ratio and the specific concentrations of actin and filamin. To relate the present results to earlier studies, we examined mixtures of actin and filamin using a macroscopic assay of gelation (tube tipping assay), and polarized light microscopy. The effect of increasing filamin concentration in the four assays was compared at three actin concentrations. Mixtures of actin and filamin whose apparent viscosities were low enough to be estimated by falling ball viscometry were optically isotropic fluids that flowed out of inverted test tubes. Mixtures of actin and filamin in the range of sensitivity of the meniscus depletion assay were either viscous fluids or gels, and were either optically isotropic or anisotropic. Thus, the four assays provide different estimates of gelation. Both the meniscus depletion assay and falling ball viscometry can be used to determine relative gelation activity, but neither can be used as a quantitative assay of gelation.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 1-5 
    ISSN: 0886-1544
    Keywords: motility ; power output ; muscle ; flagella ; cytokinetic furrow ; mitotic spindle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cellular motile systems as diverse as muscle and the mitotic spindle have been compared by their specific power output: the maximum power they develop per unit of engine volume. Striated muscles and flagella have high specific output; their performance is comparable to that of typical automobile engines. The cytokinetic furrow and the mitotic spindle have very much lower specific power output. The furrow's output is 7,000 times lower than muscle and the spindle's is 300,000 times lower. Different macromolecules have been used to generate power in systems with similar output (muscles and flagella) and, conversely, the same macromolecular motor has been used in systems with very different output (muscles and cytokinetic furrows). The common feature amid this diversity is adaptation to a particular biological role, which specific power output reflects very well. High values are found where a powerful, compact engine should be advantageous, while low values are found where precision, not power, matters most.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 469-503 
    ISSN: 0886-1544
    Keywords: cytogel ; actomyosin ; Physarum ; oscillations ; mechanics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The contractility of actomyosin gels is the basis for a variety of cellular motility phenomena. We present here a mechanical analysis of contractile gels. By making certain hypotheses on the chemical regulation of cytogel contraction we formulate a model for the rhythmic contractions of plasmodia in the slime mold Physarum polycephalum which is in accord with a number of experimental observations.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 57-71 
    ISSN: 0886-1544
    Keywords: actin ; calcium ; coelomocytes ; ionophore ; pH ; shape transformation ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the ability of the Ca+ + ionophore A23187 to induce the transformation of petaloid sea urchin coleomocytes to the filopodial form. The response of individual cells to different media was observed with time-lapse phasecontrast video microscopy. In the presence of 1 mM CaCl2, isotonic medium containing 1-5 μM A23187 produces a similar shape transformation to that caused by hypotonic shock. Higher concentrations of ionophore (10-20 μM) induce the formation of filopodia that are thinner and less rigid than those generated by hypotonic shock or low doses of ionophore. A23187 also induces shape transformation in highly flattened cells that do not respond fully to hypotonic shock. The induction of cytoplasmic alkalinization by NH4Cl, methylamine-HCl, or the Na+ ionophore monensin does not induce shape transformation, suggesting that increased intracellular pH is not the stimulus for this process. Ultrastructural changes in cytoskeletal organization were examined in negatively stained detergent-extracted cells. Low doses of ionophore produce filopodia that are indistin-guishable from those of hypotonically shocked cells, with actin filament bundles that are straight and cohesive along their entire length. High concentrations of ionophore produce filopodia with filament bundles that branch repeatedly and splay apart near their tips, forming loops and irregular curves. These results suggest that an increase in intracellular free Ca+ + concentration acts as the trigger that stimulates coelomocyte shape transformation, but that abnormally high concentrations of intracellular Ca+ +, produced by high doses of ionophore, interfere with actin filament bundling.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 121-128 
    ISSN: 0886-1544
    Keywords: axonal transport ; ATP ; nucleotides ; saltatory movement ; dynein ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a permeabilized axon model, exogenous ATP can reactivate intraaxonal saltatory organelle movements (microscopically visible manifestations of fast axonal transport). We have studied the dependence of the reactivated movements on the ATP concentration and have also examined the nucleotide specificity of the reactivation. Organelle transport was visualized in isolated lobster giant motor axons using Nomarski optics and video microscopy. The axons were permeabilized with saponin, and movement was reactivated with ATP or other nucleotides. Some slight movement was seen with ATP concentrations as low as 10 μM. The velocity and frequency of the reactivated transport increased with increasing ATP concentrations up to about 5 mM. Movement was also reactivated by deoxyadenosine triphosphate, but not by AMP-PNP (a nonhydrolyzable ATP analogue), ADP, or AMP. Although other nucleotides (CTP, GTP, UTP, ITP) could reactivate transport, movement equivalent to that produced by 0.1 mM ATP was only seen with tenfold or greater concentrations of the other nucleotides. This pattern of specificity is consistent with the hypothesis that a dynein-like ATPase, rather than a myosin, is involved in fast axonal transport.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 137-149 
    ISSN: 0886-1544
    Keywords: anti-fluorescein ; fluorescent analog cytochemistry ; molecular cytochemistry ; microinjection ; actin ; acetamidofluorescein-actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent analogs of cellular components are finding increasing use in the field of cell biology. The power of this technique can be augmented by the use of antibodies specific for the fluorophore to visualize selectively the fluorescent analog at the electron microscope level. Rabbit antibodies specific for fluorescein were elicited and purified according to published methods (Lopatin and Voss [1971]: Biochemistry 10:208). Immune sera and IgG formed precipitin lines with fluorescein-labeled proteins in Ouchterlony immunodiffusion assays, and significantly quenched the fluorescence of fluorescein-labeled proteins. Immune IgG and Fab fragments decorated fluorescein-labeled actin, but not unlabeled actin, in negative-stained preparations. Anti-fluorescein IgG was used for immunofluorescent localization of fluorescein-labeled actin following microinjection of the fluorescent analog into living cells. This approach was extended to the immunoelectron microscopic localization of the injected analog at the subcellular level by the use of an electron-dense marker coupled to goat anti-rabbit IgG. Many other fluorescent probes also can be used as haptens for production of antibodies. Therefore, a general method for localizing fluorescently labeled molecules at the electron microscopic level is now available. Several other applications of anti-fluorescein antibody in studies involving fluorescent analogs are also suggested.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 76-76 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Keywords: fast axonal transport ; mitochondria ; membrane receptors ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: In living tissue, membrane-bound organelles, including mitochondria, move along parallel cytoplasmic pathways. Motion is directed and tends to be confined to a single path. Deviations from this single path motion are rare. When present, however, they tend to occur at points of intersection of cytoskeletal linear elements (LE). Such intersections are relatively uncommon in intact axons and extruded axoplasm. However, we have found that such intersections can be produced in extruded preparations by shear forces directed tangential to the axoplasmic surface.We have studied the detailed behavior of mitochondria in extruded squid axoplasm. Special attention was directed to the relationship between mitochondrial shape changes and orientation of cytoskeletal LE. The most striking of these changes in shape is branching. In this process, the mitochondrion transiently assumes a triradial (three-ended) shape. This appearance may be maintained for seconds to minutes before the normal cylindrical shape is resumed by absorption of either the newly formed end or, more commonly, one of the original ends. The frequency of branching appears to be dependent on the degree of cytoskeletal organization. It becomes more common as the number of apparent intersections between cytoskeletal LE increases. Further, the formation of new ends seems to occur along paths defined by cytoskeletal elements.These observations suggest that the mitochondrial membrane is multivalent. That is, it contains multiple sites capable of interacting with the axonal force generation apparatus. Furthermore, LE in the cytoskeleton may indicate the paths along which these interactions are permissible.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 151-153 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984), S. 231-239 
    ISSN: 0886-1544
    Keywords: pseudostereoscopy ; particle speed distribution ; velocity distribution ; fast axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe a simple method for direct visualization of the velocity distribution of particles moving against an immobile background. The technique involves pseudostereoscopic viewing of image pairs separated by an appropriate time interval in a sequential recording of the subject. Under these conditions, the positive or negative parallax arising from particle motion results in the binocular image of a particle being perceived as raised or lowered relative to an immobile background plane depending on its direction of movement, and with the degree of perceived elevation being proportional to its speed. In effect, the binocular optic axis becomes a velocity (speed) axis under these conditions. The technique is illustrated with examples of image pair sequences showing fast axonal transport in lobster and squid axons using video-enhanced differential interference contrast microscopy. However, the pseudostereoscopic method is quite generally applicable to both microscopic and macroscopic time-dependent phenomena. Particle speeds can be quantitated using standard procedures for measuring frame-to-frame particle displacements, or alternatively, by determination of parallax using stereogrammatic methods. It should be also readily adaptable for on-line monitoring of particle velocity distribution, particularly in video systems where frame buffers can be utilized to extract and present serial image pairs having any desired time separation from video-taped sequences.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 304-305 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984), S. 305-314 
    ISSN: 0886-1544
    Keywords: cell surface motility ; axopodia ; reticulopodia ; Allogromia ; Echinosphaerium (Actinosphaerium) nucleofilum ; surf-riding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mechanism responsible for the energy-dependent movement of membrane components (ie, surface motility) is unknown. Recently a potentially unifying model, termed “surf-riding” [Hewitt, 1979] or “surf-boarding” [Berlin and Oliver, 1982], has been proposed to explain surface motility. Using phase-contrast light microscopy and membrane surface markers (polystyrene microspheres), we have tested the surf-riding/surf-boarding hypothesis on two protozoan systems: the axopodia of the heliozoan Echinosphaerium nucleofilum and the reticulopodial networks of the allogromiid foraminiferans Allogromia laticollaris and Allogromia sp, strain NF. Our evidence indicates that surface motility, as displayed by these organisms, does not occur by a surf-riding/surf-boarding mechanism. Previouś observations on surface motility associated with the Chlamydomonas flagellum indicate that this system is also incompatible with the surf-boarding/surf-riding hypothesis.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 403-404 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Cell Motility and the Cytoskeleton 4 (1984), S. 405-416 
    ISSN: 0886-1544
    Keywords: cardiac muscle ; myofibril ; cell spreading ; Z bands ; alpha-actinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cardiac myocytes were isolated from 5-6-day-old chick embryos and allowed to spread in culture. The distribution of alpha-actinin in the cells was followed for five days in culture by exposing permeabilized cells to rhodamine-labeled alpha-actinin and also by injecting the labeled alpha-actinin into living myocytes. In addition to labeling the Z bands of sarcomeres, the added alpha-actinin also labeled small particles that were usually arranged periodically in linear arrays with a spacing between particles of 0.3-2.0 μm. Actin was localized between the particles of alpha-actinin by means of fluorescein-labeled heavy meromyosin. The punctate localization of alpha-actinin was prominent in pseudopods, behind ruffles, and at the periphery of spreading cells. Long rows of particles of alpha-actinin were often parallel to one another with the alpha-actinin particles in register. These linear arrays appeared to merge laterally to form strands with broader concentrations of alpha-actinin. Other linear arrays were parallel to myofibrils in the cell and some extended outward from the ends of myofibrils. We conclude that during spreading of cardiac myocytes, myofibrils form at the cell periphery behind the extending margins of the cell, and that the aggregates of alpha-actinin found in these areas are nascent Z bands in the forming myofibrils.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 249-267 
    ISSN: 0886-1544
    Keywords: Paramecium ; trifluoperazine ; cilia ; calmodulin ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Trifluoperazine (TFP), a drug that binds to Ca2+-calmodulin (CaM) complexes, altered swimming behavior not only in living paramecia, but also in reactivated, Triton-extracted “models” of the ciliate. By comparing the responses of living cells and models, we have ascertained that two sites of drug action exist in paramecium cilia. Swimming movements were recorded in darkfield stroboscopic flash photomicrographs; this permitted accurate quantitation of velocities and body-shape parameters. When living paramecia were incubated in a standard buffer containing 10 μM TFP, their speed of forward swimming fell over several minutes and their bodies shortened. Untreated paramecia backed up repeatedly and frequently upon transfer to a solution containing barium ions (the “barium dance”), but cells preincubated in TFP did not “dance.” Instead they swam forward slowly for long periods of time without reversing and occasionally then exhibited abnormally prolonged reversals. W7 effects on swimming mimicked low doses of TFP, and the analog W5 did not visibly alter normal swimming patterns. These results suggest that TFP induces a decrease in the intracellular pCa of living paramecia, perhaps by reducing the efficiency of a calmodulin-activated calcium pump in the cell membrane. Paramecia extracted with Triton X-100 and reactivated to swim forward (7 ≥ pCa ≥ 6) were not affected by addition of up to 40 μM TFP to the reactivation medium. We conclude that the main drug effect in living cells is probably not at the axoneme. However, at low pCa, TFP directly affected the ciliary axoneme to shift its behavior to one characteristic of a higher pCa: TFP inhibited backward swimming in models reactivated at pCa 〈 6; instead they swam forward or rocked in place. The mechanism of ciliary reversal in paramecium may therefore depend on an axonemal Ca+-sensor, possibly bound CaM, which is affected by TFP only at low pCa, as has been postulated for other types of cilia.
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    Cell Motility and the Cytoskeleton 4 (1984) 
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 72
    ISSN: 0886-1544
    Keywords: microtubule ; tubulin ; MAPs ; calcium ; mitosis ; unfertilized sea urchin egg ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic tubulin purified from unfertilized sea urchin eggs self-assembles in the absence of microtubule-associated proteins (MAPs) [Suprenant and Rebhun, 1983; Detrich and Wilson, 1983] with a critical concentration for polymerization of 0.8 mg/ml at 15-18°C, a value well below the 3 mg/ml tubulin present in these eggs [Pfeffer et al, 1976]. Studies of the calcium sensitivity of unfertilized S. purpuratus (sea urchin) egg tubulin were initiated to help understand how this tubulin is maintained unassembled in the unfertilized egg. Egg microtubules, assembled at physiological temperatures (15-18°C) were depolymerized by a 100-fold lower free calcium concentration than egg microtubules assembled at the higher temperatures (25-37°C) generally used to assemble mammalian brain microtubules. The initial rate of egg microtubule assembly was much more sensitive to calcium than was microtubule depolymerization at steady state at 37°C. However, both processes were sensitive to near physiological free calcium of free calcium for depolymerization than microtubules assembled at 18°C from egg tubulin alone. While calcium regulatory MAPs have not yet been found in sea urchin eggs, the fact that brain MAPs interact with egg tubulin and regulate both its critical concentration for polymerization [Suprenant and Rebhun, 1983] and its calcium sensitivty, suggests that such regulatory molecules exist. These results suggest that sea urchin egg tubulin assembly in vivo could be controlled by variations in interacellular calcium levels acting in concert with urchin egg proteins similar in function to brain MAPs.
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  • 73
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    Cell Motility and the Cytoskeleton 4 (1984), S. 387-401 
    ISSN: 0886-1544
    Keywords: bull sperm flagella ; motility ; time course ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Detailed measurements were made of the time course of the motion of bull spermatozoa. Fourier analysis of the data showed the time course to be basically sinusoidal within 2% to 3%. An asymmetry in the motion was present, resulting in a second harmonic component in the Fourier spectra of normal sperm of approximately 11% of the main component. When the energy metabolism of the sperm was inhibited or when the external viscosity of the medium was raised, the asymmetry was reduced. When the internal Mg2+ content of the sperm was lowered, the asymmetry was increased. The asymmetries and the corresponding second harmonic components in the Fourier spectra were correlated with the overall bend shape of the sperm and with the curvature of the path in which the sperm were swimming. Model calculations showed that the asymmetry could reside in either the internal active moments in the sperms or in the stiffness of the sperm fiagella.
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  • 74
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    Cell Motility and the Cytoskeleton 4 (1984), S. 443-468 
    ISSN: 0886-1544
    Keywords: actin ; microfilaments ; HMM ; phagocytosis ; cytochalasin ; Paramecium ; fluorescence microscopy ; electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using heavy meromyosin (HMM) or the fragment S1 of myosin as probes for actin microfilaments, we studied their organization in Paramecium both by fluorescence and electron microscopy.In interphasic cells, HMM decorates (a) most prominently the periphery of nascent and young food vacuoles and their route during the early phase of their intracellular transit; (b) a thin meshwork radiating from the gullet throughout the cytoplasm; (c) a small area beneath the pore of contractile vacuoles and beneath the cytoproct when open to release food residues. Most of these HMM-decorated structures are in close contact with microtubular arrays. All HMM decoration disappears in dividing cells and in cytochalasin-treated cells. In vivo, the drug immediately blocks food vacuole formation but does not affect cytokinesis, cyclosis, contractile vacuole pulsation, defecation, or nuclear movements.The data show that, as in the cells of other organisms, actin microfilaments form defined arrays that undergo physiologically controlled cycles of assembly/disassembly. These arrays contribute (at least in the phagocytotic process) to diverse types of movement: constriction, membrane fusion, and migration of food vacuoles. However, aside from their massive concentration along the phagocytotic tractus, actin microfilaments are neither major structural components of Paramecium cytoplasm nor the only cytoskeletal components ensuring motility or contractility processes.
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  • 75
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    Cell Motility and the Cytoskeleton 4 (1984), S. 155-167 
    ISSN: 0886-1544
    Keywords: taxol ; microtubules ; mitosis ; mitotic spindle ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Taxol stabilizes or promotes the assembly of microtubules. In this report we characterize the rate, extent, and reversibility of taxol stabilization of calciumlabile microtubules in isolated mitotic spindles, principally from embryos of the sand dollar Echinarachnius parma. The intense depolymerizing action of 100 μM Ca2+ was used to assess the extent of stabilization by taxol. Changes in spindle microtubule assembly were evaluated and recorded by measuring changes in spindle birefringent retardation (BR). Membrane-free mitotic spindles, isolated with a calcium-chelating, nonionic detergent buffer, were stored in an EGTA-gylcerol storage buffer to prevent microtubule depolymerization. When perfused with an EGTA-buffer without glycerol, microtubules in these isolated spindles depolymerized gradually over 60-120 min; but in isolated spindles perfused with buffer that contained 100 μM Ca2+, BR decreased by 90% within 2-5 sec. In contrast, spindles that were pretreated for 3 min with 1 μM taxol, or for about 30 sec with 10 μM taxol, lost less than 10% of their initial BR when perfused with buffer containing 100 μM Ca2+. The rate and extent of microtubule stabilization by taxol depended on both the concentration and the duration of exposure to taxol. Taxol stabilization was reversible. After a 15 min preincubation with 1 μM or 10 μM taxol then washout, stability of spindle BR to 100 μM Ca2+ decreased exponentially with a time constant of 30-60 min. Thus taxol dissociates from spindle microtubules at significant rates; taxol-stabilized microtubules are not “fixed.”
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    Cell Motility and the Cytoskeleton 4 (1984), S. 215-226 
    ISSN: 0886-1544
    Keywords: sperm motility ; flagellum ; axoneme ; microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Iontophoretic application of ATP to the flagellum of the demembranated hamster spermatozoon produced a planar pair of bends at the two ends of the stimulated site. During bend propagation, torsion appeared in the vicinity of the interbend in some responses such that the distal bend was twisted clockwise when viewed from the base of the flagellum. This pattern of propagation is consistent with the instantaneous configurations of free-swimming cells previously described. The technique used here establishes that the three dimensionality arises from propagation per se, and does not depend on forces developed during swimming. The rolling of both free-swimming intact and demembranated spermatozoa was examined by two-color darkground videomicroscopy and the direction of rotation was, as predicted, always anticlockwise. A hypothetical mechanism, involving differential speeds of propagation of active sliding within the active microtubule subset, is proposed to account for the observed waveforms.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 283-295 
    ISSN: 0886-1544
    Keywords: axonemal mutants ; Ca++ response ; ciliary reversal ; electrophysiology ; models ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Six mutants of Paramecium tetraurelia, which display altered axonemal responses to Ca++, are described. The mutants, designated atalantas, are impaired in their ability to swim backward when stimulated by ions or heat; instead they spin very rapidly in one place. Three mutants, ataA1-3, are completely unable to swim backward. The three lines, however, can be distinguished from one another by their forward swimming velocities. The remaining three mutants are leaky. ataB swims backward briefly when stimulated, then stops and spins in place. ataC and ataD are extremely leaky and only display the spinning phenotype at elevated temperatures. An electrophysiological analysis reveals that all six mutants have normal membrane properties, including the Ca++ inward current under voltage clamp. When the membrane is disrupted so as to allow the axoneme free access to Ca++, wild-type cells swim backward, but the mutants do not. These data indicate the site(s) of lesion in the mutants is in the axoneme or in some step linking Ca++ influx and the axoneme, not within the ciliary membrane. These mutants may be useful in investigating the role of Ca++ in the regulation of axonemal motion.
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    Cell Motility and the Cytoskeleton 4 (1984), S. 351-370 
    ISSN: 0886-1544
    Keywords: axon ; rate ; nervous system ; tissue culture ; cell growth ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A new formula calculates rates of directed axonal growth (elongation or retraction) using measurements of growth cone movements. By explicitly separating changes in axonal length from other nonelongational growth cone movements, the calculated rates reflect the detailed cellular growth mechanisms more directly than previous growth measures. In addition, the formula produces three distinct parameters of axonal elongation: n, a growth step rate; s, a growth step size; and P, a probability that a growth step leads to axonal elongation. For normal and regenerating individual chick and frog axons in culture, the formula has quantitated the following differences: the axon itself can elongate more rapidly in the chick, and the axon elongates in smaller steps in the chick. The underlying dynamics of growth of regenerating axons are quite similar to normal axons, but, in the short term, regenerating axons elongate in larger steps and at a slower rate. The distribution of these new rate measurements suggests that the elongation of axons can be usefully modelled as a one-dimensional stochastic walk.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2337-2350 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hetero-π-Systems, 7. SilabenzeneFlash pyrolysis of silacyclohexadiene derivatives 5k, 5m, and 7b yields silabenzene (1), which can be isolated in an argon matrix at 10 K. 1 exhibits characteristic IR and UV spectra. By photoexcitation a mutual interconversion between silabenzene (1) and dewarsilabenzene (2) can be achieved.
    Notes: Durch Kurzzeitpyrolyse der drei Silacyclohexadien-Derivate 5k, 5m und 7b läßt sich Silabenzol (1) erzeugen und in einer Argonmatrix bei 10 K isolieren. 1 zeichnet sich durch charakteristische IR- und UV-Spektren aus. Mittels photochemischer Anregung ist eine gegenseitige Umwandlung zwischen Silabenzol (1) und Dewarsilabenzol (2) zu erreichen.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2452-2463 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of 1,3,5-TristyrylbenzeneDepending on the reaction conditions the irradiation of the title compound 1 yields the cyclophane 5, the pyrene derivative 6, or the polycondensed aromatic system 9. An X-ray analysis was performed for 5, representing a new type of cyclophane in which two benzene rings are bridged again by rings.
    Notes: In Abhängigkeit von den Reaktionsbedingungen erhält man bei der Belichtung der Titelverbindung 1 das Cyclophan 5, das Pyrenderivat 6 oder das polykondensierte aromatische System 9. Für den neuen Cyclophantyp 5, bei dem zwei Benzolringe selbst wieder durch Ringe verbrückt sind, wurde eine Röntgenstrukturanalyse durchgeführt.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2469-2478 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropenes as Complex Ligands: η4-Vinylketene Complexes of Manganese, Vanadium, and Cobalt; Preparative and X-ray Crystallographic ResultsThe reaction of 1,2,3-triphenylcyclopropene with (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 and Co2(CO)8 yields via ring opening and carbonylation the new compounds LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) and L2Co2(CO)4 (6) (L = η4-C3Ph3HCO), respectively. In the reaction with (η5-C5H5)Co(CO)2 additionally the formation of 2,3-diphenylindenone (5) is observed. The X-ray structures of 1, 3 and 5 have been determined.
    Notes: Die Umsetzung von 1,2,3-Triphenylcyclopropen mit (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 und Co2(CO)8 ergibt unter Ringöffnung und Carbonylierung die neuen Verbindungen LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) bzw. L2CO2(CO)4 (6) (L = η4-C3Ph3HCO). Bei der Reaktion mit (η5-C5H5)Co(CO)2 wird außerdem die Bildung von 2,3-Diphenylindenon (5) beobachtet. Die Röntgenstrukturen von 1, 3 und 5 wurden bestimmt.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2495-2503 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1401). Boron, Aluminium, and Gallium Halide Adducts of a Tetraaminodiboron CompoundThe tetraamino diboron compound 1 adds trihalides EX3 (E = B, Al, Ga, X = Cl, Br, I) to yield 1:1- and 1:2-coordination compounds. The BBr3 adduct 1b is thermally stable and shows nonfluxional behaviour in solution in contrast to the AlCl3 and GaCl3 adducts. The 1:2 adducts are nonfluxional and, according to NMR spectra, only the meso-form is present. The structure of the 1:1-adducts was ascertained by an X-ray structure determination of 1g. The single crystal contained R configurated molecules. A change from planar to the envelope conformation of the diazaborolidine ring occurs on adduct formation.
    Notes: Die Tetraaminodibor-Verbindung 1 lagert die Trihalogenide EX3 (E = B, Al, Ga; X = Cl, Br, I) zu 1:1- bzw. 1:2-Koordinationsverbindungen an. Von diesen zeigt nur das thermisch stabilere BBr3-Addukt 1b in Lösung im Gegensatz zu den AlCl3- und GaCl3-Addukten kein fluktuierendes Verhalten. Die 1:2-Addukte sind starr, und nach NMR-Spektren bildet sich nur die meso-Form. Die Struktur der 1:1-Addukte wurde durch Röntgenstrukturanalyse von 1g gesichert; die Einkristalle enthielten ein R-konfiguriertes Molekül. Durch die Addition nimmt der sonst planare Diazaborolidin-Ring Briefumschlag-Konformation an.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2504-2509 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1411). Unexpected Formation of a Bis(amino)borane: Synthesis and Structure of Bis(benzyl-tert-butylamino)boraneThe reaction of BCl3 with 3 molar equivalents of lithium benzyl-tert-butylamide produces the bis(amino)borane 2 in 29% yield. According to an X-ray structure determination the compound crystallizes in the monoclinic system, space group C2/c, and the molecule possesses almost C2 symmetry. The mean BN bond lenght is 142 pm, and the C2N planes are twisted by an average of 23.8° versus the HBN2 plane.
    Notes: Die Umsetzung von BCl3 mit 3 mol Lithium-benzyl-tert-butylamid liefert mit 29% Ausbeute das Bis(amino)boran 2. Nach Röntgenstrukturanalyse der monoklin in der Raumgruppe C2/c kristallisierenden Verbindung besitzt das Molekül nahezu C2-Symmetrie. Der durchschnittliche BN-Abstand beträgt 142 pm, und die C2N-Ebenen sind gegen die HBN2-Ebenen um durchschnittlich 23.8° verdrillt.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2479-2494 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 139. Addition Compounds of Alkylhalogenoboranes with 1,3,2-Diazaborolidines: Structure, Stability, and Exchange ReactionsReactions of alkylhalogenoboranes RnBX3 - n (n = 0 - 2) with the 1,3-dimethyl-1,3,2-diazaborolidines 1 - 4 yield stable 1:1 addition compounds 1a - e, 2a, 3a - d, 4a irrespective of the boron substituents. Coordination of the borane moiety occurs at a ring N atom. An X-ray structure determination of the BCl3-adduct 3a shows two enantiomers in the asymmetric unit, envelope ring conformation, and strong π-bonding between the non-coordinated B an N atoms. - Equilibria of the 1:1 adducts with their ring cleavage products and their behaviour towards a second mol of BX3 was studied. In this case, replacement of the ring-BR group occurs. In contrast, haloboranes react with the 2-(dimethylamino)diazaborolidine 5 with R2N-substituent exchange while diborane yields in the first instance the (dimethylamino)borane adduct 5a.
    Notes: Umsetzungen von Alkylhalogenboranen RnBX3 - n (n = 0 - 2) mit den 1,3-Dimethyl-1,3,2-diazaborolidinen 1 - 4 führen unabhängig vom Bor-Substituenten zu stabilen 1:1-Additionsverbindungen 1a - e, 2a, 3a - d, 4a, wobei die Koordination über ein N-Atom des Fünfrings erfolgt. Die Röntgenstrukturanalyse des BCl3-Addukts 3a zeigt zwei enantiomere Formen in der asymmetrischen Einheit, “envelope”-Ringkonformation und eine starke π-Rückbindung des Ringbors zum nicht koordinierten Stickstoff. - Gleichgewichte der 1:1-Additionsverbindungen mit ihrem Ringöffnugsprodukt sowie ihr Verhalten gegenüber einem zweiten mol Lewis-Säure wurden untersucht. Hierbei wird die Ring-BR-Gruppe verdrängt. Im Gegensatz dazu tauscht das 2-(Dimethylamino)diazaborolidin 5 mit Halogenboranen den R2N-Substituenten aus, während die Umsetzung mit Diboran zunächst ein wenig stabiles (Dimethylamino)boran-Addukt 5a liefert.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2527-2530 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal Ketene Compounds, XXII. Anionic η2-Ketenyl Complexes of Molybdenum and TungstenAnionic η2-ketenyl complexes [NR4′]{η5-C5H5(CO) (CN)M[η2-O=C=C—R]} [M = molybdenum: 3a, b; M = tungsten: 4a - c] are formed by ligand substitution on neutral η2-ketenyl compounds as well as by reaction of dicarbonyl(η5-cyclopentadienyl)carbyne complexes with tetraalkylammonium cyanides.
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminyl Oxides (Nitroxides), XXXV. The Tricyclic Dimer of a Vinyl Aminyl Oxide (Vinyl Nitroxide) and its Isomerization to give a 2,4,7,9-Tetraoxa-5,10-diazatetracyclo[4.4.2.03,12.08,11]dodecaneVinyl aminyl oxide 6 is formed by oxidation of hydroxylamine 3 via the intermediates 4 and 5. Dimerization of 6 yields the tricyclic compound 8. In solution dissoziation of 8 occurs at approximately 40°C, four bonds being cleaved to afford radical 6. By prolonged heating in various solvents as well as by proton catalysis at room temperature 8 is rearranged to give the tetracyclic isomer 9, the structure of which has been confirmed by X-ray analysis.
    Notes: Das Vinylaminyloxid 6 entsteht bei der Oxidation des Hydroxylamins 3 über die Zwischenstufen 4 und 5. 6 dimerisiert unter Bildung der tricyclischen Verbindung 8. 8 dissoziiert in Lösung bereits bei etwa 40°C unter Spaltung von vier Bindungen in das Radikal 6. Durch längeres Erhitzen in verschiedenen Lösungsmitteln, aber auch unter Protonenkatalyse bei Raumtemperatur, wird 8 in ein tetracyclisches Isomeres 9 umgewandelt. Die Struktur von 9 wurde durch Röntgenstrukturanalyse ermittelt.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 3-Metalated Enamines, X. Formation and Reactivity of 1-(Diethoxyphosphoryl)-1-(dimethylamino)allyl Anions1-Phosphorylenamines 8 and 10 react regio- and stereoselectively after deprotonation as anions 8A and 10A with silylating and alkylating reagents to give homologous (E)-1-phosphorylenamines 13, 15, 19 - 32. These can be hydrolyzed to give the corresponding carboxylic acids alkylated at C-3. Deprotonation of 10 occurs always on the methyl group cis to the phosphoryl group. The primarily formed anion isomerizes rapidly about the C-1 - C-2 bond. The highly regio- and stereoselective deprotonation allows the controlled introduction of up to three different alkyl groups. The results of NMR spectroscopic investigations of 8A and 10A are discussed.
    Notes: Die 1-Phosphorylenamine 8 und 10 reagieren nach Deprotonierung als Anion 8A und 10A regio-und stereoselektiv mit Silylierungs- und Alkylierungsmitteln zu homologen (E)-1-Phosphorylenaminen 13, 15, 19 - 32. Diese lassen sich zu den entsprechenden in 3-Stellung alkylierten Carbonsäuren hydrolysieren. Bei 10 erfolgt die Deprotonierung stets an der zur Phosphorylgruppe cis-ständigen Methylgruppe. Anschließend isomerisiert das primär gebildete Allyl-Anion rasch um die C-1 - C-2-Bindung. Diese hohe Regio- und Stereoselektivität der Deprotonierung gestattet die gezielte Einführung von bis zu drei verschiedenen Alkylgruppen. Die Ergebnisse der NMR-spektroskopischen Untersuchung von 8A und 10A werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2839-2849 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chromoionophores, 51). Chromoionophores with Azulene Units as Chromophores and π-Donor ComponentsThe synthesis and spectroscopic investigation of a series of new chromoionophores with azulene as chromophore and of suitable reference compounds are described. Cations complexed by the ionophore influence the chromophore, causing downfield shifts in the 1H NMR spectra and ion-selective changes in the absorption spectra. It is concluded that the chromophore can interact with the cations via carboxylic oxygen atoms or directly via the π-electrons of the azulene unit. Crystalline complexes of the azulene ligands 6 and 7 with alkali and alkaline-earth metal salts are synthesized. The geometry of the 7 · KSCN complex is examined by X-ray structure analysis.
    Notes: Synthese und spektroskopische Untersuchung einer Reihe von neuen Chromoionophoren mit Azulen als Farbträger und von geeigneten Vergleichsverbindungen werden beschrieben. Die Beeinflussung des Chromophors durch im Ionophorteil komplexierte Kationen verursacht in Lösung 1H-NMR-Tieffeldverschiebungen und ionenselektive Veränderungen in den Elektronenspektren. Daraus wird gefolgert, daß der Chromophor über Carboxyl-Sauerstoffatome oder direkt über die π-Elektronen des Azulens mit den Kationen in Wechselwirkung treten. Kristalline Komplexe der Azulen-Liganden mit Alkali- und Erdalkalimetallsalzen werden hergestellt. Die Geometrie des 7 · KSCN-Komplexes wird durch Röntgenstrukturanalyse ermittelt.
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  • 90
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2875-2885 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Unsaturated Aldehyde Dimethylhydrazones with Electrophilic ReagentsCrotonaldehyde dimethylhydrazone (1) is substituted at C-3 by electrophiles such as chlorine, bromine, iodine, arylsulfenyl chloride, phenylsulfinyl chloride, and nitronium tetrafluoroborate to form the products 10a  -  c, 18a, b, 25, and 26. In contrast, from 1 and p-nitrobenzoyl chloride the dienehydrazide 3 is obtained. Acrolein dimethylhydrazone reacts with diazoacetic ester to give the cyclopropane derivative 29. Isoxazole 32 is obtained from 28 and p-chlorobenzonitrile oxide.
    Notes: Crotonaldehyd-dimethylhydrazon (1) wird durch elektrophile Reagenzien wie Chlor, Brom, Iod, N-Chlorsuccinimid, Arylsulfenylchlorid, Phenylsulfinylchlorid oder Nitryl-tetrafluoroborat and C-3 unter Bildung der Produkte 10a  -  c, 18a, b, 25 und 26 substituiert. Bei Einwirkung von p-Nitrobenzoylchlorid auf 1 erhält man dagegen das Dienhydrazid 3. Acrolein-dimethylhydrazon (28) reagiert mit Diazoessigester zum Cyclopropanderivat 29, mit p-Chlorbenzonitriloxid zum Isoxazolin 32.
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  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2886-2899 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Partially Substituted Tetrazenes (Me3E)nN4H4 - n (E = Si, Ge, Sn): Preparation, Characterization, and Thermolysis1)Partially substituted tetrazenes (Me3E)nN4H4 - n (E = Si, Ge, Sn) can be prepared by protolysis of higher substituted tetrazenes (Me3E)oN4H4 - o (O 〉 n) or by silylation, germylation, or stannylation of lower substituted tetrazenes (Me3E)mN4H4 - m (m 〈 n). The obtained tetrazenes (Tab. 1) are colorless compounds; they have 2-tetrazene constitution, and trans-tetrazene configuration. The tetrazene (Me3Si)2N  -  N = N  -  NHX (X = H or GeMe3) isomerize by heating in dilute solution into (Me3Si)XN  -  N = N  -  NH(SiMe3). The thermolysis of (Me3Si)2N  -  N = N  -  NH(SiMe3) leads mainly to Me3SiN3 and (Me3Si)2NH (t140°C1/2140°C = 3/4 h), of (Me3Si)2N  -  N = NH2 to Me3SiN3 and Me3SiNH2 (concentrated solution; t140°C1/240°C ca. 1/4 h), and of (Me3Si)HN  -  N = N  -  NH(SiMe3) to N2 and (Me3Si)2N  -  NH2 (dilute solution; t140°C1/2140°C 〉 1 h) or to NH3 and (Me3Si)2NH (concentrated solution; t140°C1/2 〈 1 h).
    Notes: Teilsubstituierte Tetrazene (Me3E)nN4H4 - n (E = Si, Ge, Sn) können durch Protolyse höher substituierter Tetrazene (Me3E)oN4H4 - o (O 〉 n) oder durch Silylierung, Germylierung bzw. Stannylierung niedriger substituierter Tetrazene (Me3E)mN4H4 - m (m 〈 n) dargestellt werden. Die gewonnenen Tetrazene (Tab 1) sind farblose Verbindungen: sie haben 2-Tetrazen-Konstitution und trans-Tetrazen-Konfiguration. Die Tetrazene (Me3Si)2N  -  N = N  -  NHX (X = H oder GeMe3) isomerisieren sich in verdünnter Lösung beim Erhitzen in (Me3Si)XN  -  N = N  -  NH(SiMe3). Die Haupttermolyse von (Me3Si)2N  -  N = N  -  NH(SiMe3) führt zu Me3SiN3 und (Me3Si)2NH (t140°C1/2140°C = 3/4 h), von (Me3Si)2 (Me3Si)2N  -  N = NH2 zu Me3SiN3 und Me3SiNH2 (konzentrierte Lösung; t140°C1/240°C ca. 1/4 h) und von (Me3Si)HN  -  N = N  -  NH(SiMe3) zu N2 und (Me3Si)2N  -  NH2 (verdünnte Lösung; t140°C1/2140°C 〉 1 h) oder zu NH3t140°C und (Me3Si)2NH (Konzentrierte Lösung; t140°C1/2140°C 〈 1 h).
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  • 92
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2900-2909 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Assignment of Configuration of Larger Bicyclo[n.1.0]alkyl Amines: The Hexahydro-1-azepinyl Residue as „Stereo Indicator“The temperature dependency of the 1H NMR spectra of the hexahydro-1-azepinylbicyclo[9.1.0]-dodecanes 3a  -  f is investigated. The ΔG≠-values of the hexahydroazepine dynamics permit an easy assignment of the endo-amino configuration in 3a  -  f. Starting from 3a, which is synthesized via the enaminosulfonium salt 7, the derivatives 3b  -  f are obtained by nucleophilic substitutions. Normally the cis-configuration of the bicyclo system is not changed during these reactions. However, reaction of the cis-compound 3a with hexahydroazepine leads either to a cis-aminal 3e or to a trans-aminal 4e depending on the conditions of the reaction.
    Notes: Die aus der Temperaturabhängigkeit der 1H-NMR-Spektren der Hexahydro-1-azepinylbicyclo [9.1.0]dodecan-Derivate 3a  -  f ermittelten ΔG≠-Werte der Hexahydroazepinyl-Dynamik ermöglichen eine einfache Festlegung der endo-Amino-Konfiguration. Die Verbindungen 3b  -  f werden aus 3a über eine Folge nucleophiler Substitutionen erhalten; 3a ist über das Enaminsulfonium-Salz 7 zugänglich. Normalerweise bleibt die cis-Konfiguration des Bicyclosystems bei den Substitutionen erhalten. Jedoch führt die Umsetzung der cis-Verbindung 3a mit Hexahydroazepin  -  abhängig von den Reaktionsbedingungen  -  zu einem cis-Aminal 3e oder einem trans-Aminal 4e.
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  • 93
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2910-2927 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Aminobicyclo[n.1.0]alkanes, I Thermolysis of Aminobicyclo[n.1.0]alkanes with a Dimedone MoietyFrom the bicyclic aminals 4 and dimedone (5) derivatives 6 are obtained, which give different types of products upon thermolysis depending on the ring size of the bicyclus. The bicycloheptane and -octane compounds 6b, c lead to diacylated enamines 8b, c by protonation of the cyclo-propane ring. Contrarily, an elimination of morpholine takes place in 6a, d, e containing a bicyclohexane, -undecane, or -dodecane ring. There are formed derivatives with an exo-methylenefuran unit, which has a Z-configuration in 17a and an E-configuration in 16d, e. 16e the product of a kinetically controlled reaction, rearranges via the Z-isomer 17e to give the furan 18e by heating in morpholine. A methylenebicyclo[n.1.0]alkane 14 is discussed to be an intermediate in the formation of 16d, e and 17a, respectively.
    Notes: Aus den bicyclischen Aminalen 4, und Dimedon (5) werden Derivate 6 erhalten, die in Abhängigkeit von der Ringgröße des Bicyclus unterschiedliche Thermolyseprodukte ergeben. Die Bicycloheptan- und -octanverbindungen 6b, c, führen unter Protonierung des Cyclopropanrings zu Diacylenaminen 8b, c. Eine Eliminierung von Morpholin wird dagegen bei 6a, d, e mit einem Bicyclohexan-, -undecan- bzw. -dodecan-Ring beobachtet. Dabei entstehen Verbindungen mit einem exo-Methylenfuran-Strukturelement, das bei 17a in der Z- und bei 16d, e in der E-Konfiguration vorliegt. 16e, das kinetisch kontrollierte Reaktionsprodukt, kann durch Erhitzen in Morpholin über das Z-Isomere 17e zum Furan 18e umgelagert werden. Die Beteiligung einer Methylenbicyclo-[n.1.0]alkan-Zwischenstufe 14 beim Entstehen von 16d, e bzw. 17a wird diskutiert.
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  • 94
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 172-186 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Ions, 55. The One-Electron Oxidation of Tetrahedrane to Cyclobutadiene Radical CationTetra-tert-butyltetrahedrane, on one-electron oxidation using AlCl3 in CH2Cl2, opens to form tetra-tert-butylcyclobutadiene radical cation, which can also be generated under identical reaction conditions from tetra-tert-butylcyclobutadiene itself. The assignments of the ESR and ENDOR spectra are supported by deutero substitution of one tert-butyl group and by MNDO hypersurfaces for the thermal and for the oxidative structural changes of both C4 skeletons. The feasible formation of a valence isomeric tert-butyl(tri-tert-butylcyclopropenyl)carbene radical cation is discussed.
    Notes: Tetra-tert-butyltetrahedran öffnet sich bei Einelektronen-Oxidation mit AlCl3 in CH2Cl2 zum Tetra-tert-butylcyclobutadien-Radikalkation, das unter gleichen Reaktionsbedingungen auch aus Tetra-tert-butylcyclobutadien erzeugt werden kann. Die Zuordnungen der ESR- und ENDOR-Spektren werden durch Deutero-Substitution einer tert-Butyl-Gruppe sowie durch MNDO-Hyperflächen für die thermischen und oxidativen Strukturänderungen der beiden C4-Gerüste gestützt. Die mögliche Bildung eines valenzisomeren tert-Butyl(tri-tert-butylcyclopropenyl)carben-Radikalkations wird diskutiert.
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  • 95
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 222-233 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Dynamic Behaviour of PentamethylcyclopentadienylphosphanesBy reaction of pentamethylcyclopentadienyl(Me5cp)-lithium with halogenophosphanes the Me5cp-phosphanes 1 - 5, 7, 8, 11, 12, 14, 15, and 19 - 24 are synthesized. Substitution reactions with the Me5cp-halogenophosphanes 7 and 14 lead to the Me5cp-phosphanes 6, 9, 10, 13, and 16 - 18. These molecules posses a fluxional structure owing to 1,5-sigmatropic rearrangements of the particular phosphorus group. It is demonstrated by 1H dnmr investigations and lineshape analyses, that the ligands at phosphorus influence drastically the speed of these rearrangements (activation energies between 5 and 31 kcal/mol).
    Notes: Durch Umsetzung von Pentamethylcyclopentadienyl(Me5cp)-lithium mit Halogenphosphanen werden die Me5cp-Phosphane 1 - 5, 7, 8, 11, 12, 14, 15 und 19 - 24 hergestellt. Substitutionsreaktionen an den Me5cp-Halogenphosphanen 7 und 14 führen zu den Me5cp-Phosphanen 6, 9, 10, 13 und 16 - 18. Diese Moleküle besitzen eine fluktuierende Struktur aufgrund von 1,5-sigmatropen Umlagerungen der jeweiligen Phosphorgruppierung. Durch 1H-NMR-Untersuchungen und Linienformanalysen wird gezeigt, daß die phosphorständigen Liganden die Geschwindigkeit dieser Umlagerungen drastisch beeinflussen (Aktivierungsenergien zwischen 5 und 31 kcal/mol).
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  • 96
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyspiranes, 7. Cascade Rearrangements, 2: From Polyspiranes to Polycycles - Sixfold 1,2-Shifts in Functionalized Pentaspiro[2.0.2.0.2.0.2.0.2.1]hexadecanesThe pentaspirohexadecanes 3a, b may be rearranged to 8a, b via 7a, b, which are potential precursors of the [6.4]coronane 1. 7a and 8a were benzoylated to give 7d and 8e, respectively, the molecular structures of which were determined by X-ray analysis. 7a, b and 8a, b adopt the all-cis-configuration. 7a and 7b contain axial hydroxyl groups. The overall rearrangements of 3a, b may thus be described in terms of sixfold 1,2-shifts with inversion at both the migration origins and termini.
    Notes: Die Pentaspirohexadecane 3a, b können über 7a, b in 8a, b umgelagert werden. 7a, b sind potentielle Vorläufer des [6.4]Coronans 1. 7a und 8a wurden zu 7d bzw. 8e benzoyliert, die Molekülstrukturen von 7d und 8e röntgenographisch bestimmt. 7a, b und 8a, b sind all-cis-konfiguriert, 7a und 7b enthalten die Hydroxylgruppe axial gebunden. Die Gesamtumlagerungen von 3a, b können demnach als sechsfache 1,2-Verschiebungen unter Inversion am jeweiligen Ausgangs- und Endpunkt der Umlagerung beschrieben werden.
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  • 97
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 187-202 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas Phase Reactions, 40. Selenoformaldehyde: Highly Correlated Wave Function and Photoelectron Spectroscopic EvidenceA systematic search for the unknown molecule selenoformaldehyde, H2C = Se, starts with the precalculation of its ionization pattern from ab-initio-PNO-CI and CEPA wave functions. The selenium precursors H3CSeSeCH3, H3CSeCN, H3CSeCl, and (H2CSe)3 are pyrolyzed in a flow system under PE spectroscopic real-time analysis: Applying “computerized spectra stripping” to the PE spectra of the pyrolysis mixtures, an ionization pattern can be extracted which correlates satisfactorily with the quantum chemical prediction for H2C = Se. To further support the assignment, selenoacetaldehyde, CH3CH = Se, and selenocarbonyl difluoride, F2C = Se, are prepared by thermal monomerization of ((H3C)HCSe)3 and (F2CSe)2, respectively.
    Notes: Nach dem unbekannten Molekül Selenoformaldehyd, H2C = Se, wird systematisch gesucht, beginnend mit der Vorausberechnung seines Ionisationsmusters aus ab-initio-PNO-CI-und CEPA-Wellenfunktionen. Als Selen-Ausgangsverbindungen werden H3CSeSeCH3, H3CSeCN, H3CSeCl und (H2CSe)3 im Gasstrom unter PE-spektroskopischer Echtzeit-Analytik pyrolysiert: Aus den Pyrolysegemisch-Spektren läßt sich durch Spektren-Subtraktion mit Hilfe eines Rechners ein Ionisationsmuster herausschälen, das mit der quantenchemischen Voraussage für H2C = Se zufriedenstellend korreliert. Zur weiteren Stützung der Spektrenzuordnung werden Selenoacetaldehyd, CH3CH = Se, und Selenocarbonyldifluorid, F2C = Se, durch thermische Monomerisierung von ((H3C)HCSe)3 und (F2CSe)2 dargestellt.
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  • 98
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 234-245 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Na⊕ Complexation of New Multidentate Polyether Ligands - Rapid Estimation of Complexation Constants by 23Na NMR SpectroscopyA new 23Na NMR method for fast and simple estimation of Na⊕ complex stabilities is reported and applied to various polyether ligands. Syntheses of the new coronands and podands amongst the employed substrates are given.
    Notes: Eine neue 23Na-NMR-Methode zur raschen und zuverlässigen Abschätzung der Komplexstabilitäten für Na⊕ wird beschrieben und an Polyetherliganden unterschiedlicher Struktur erprobt. Synthesen von neuen Kronenverbindungen und Podanden, die als Meßliganden dienen, werden mitgeteilt.
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  • 99
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sterically Hindered Alkenes, IV. Preparation of Some Octamethylcycloalkylidenecycloalkanes and Related CompoundsSixteen “tied back” derivatives of tetra-tert-butylethene of type 4 were prepared via the thiadiazoline and selenadiazoline routes, resp. Strain in 4 increases with increasing number of ring members. The compounds 4m, n, p, and q represent the alkenes of highest fragmentation strain prepared so far, and the limit for the utility of the present synthetic methods. The causes for the failure of these methods in the synthesis of yet more highly strained alkenes are discussed.
    Notes: Mit Hilfe der Thiadiazolin- und Selenadiazolin-Methode wurden 16 neue überbrückte Derivate des Tetra-tert-butylethens vom Typ 4 dargestellt. Mit wachsender Ringgliederzahl nimmt die Spannung in 4 zu. Die Grenzen der erwähnten Synthesewege liegen für die Alkene bei 4m, n, p und q; sie stellen die Alkene höchster Fragmentierungsspannung dar, die bisher isoliert wurden. Die Ursachen für das Versagen dieser Methoden bei der Synthese sterisch noch stärker gehinderter Alkene werden diskutiert.
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  • 100
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 344-354 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Reactions of Transition Metal Olefin Complexes, 8. Photochemical Addition of 6-Substituted Pentafulvenes to Tricarbonyl(η6-8,8-dimethylheptafulvene)chromium(0)Under photochemical conditions 6-substituted pentafulvenes (2a - d) displace one CO ligand from tricarbonyl(η6-8,8-dimethylheptafulvene)chromium(0) (1) with formation of a C - C bond between C-6 of a fulvene and C-1 of the heptafulvene ligand leading to substituted dicarbonyl-[η5:3-(cyclopentadienediyl)(isopropylidenecycloheptadienediyl)methane]chromium complexes (3a - 5c). In all cases two diastereomeric complexes are formed, which are separated by column chromatography. They differ in the location of the η3-enyl systems. In 3a, d the enyl system encompasses C-1′ to C-3′, in 4a, b, d C-1′, C-7′, and C-8′, and in 5b, c C-3′ to C-5′ in the isopropylidenecycloheptadienediyl residue. The structures of the complexes 3a - 5c were derived from the spectra.
    Notes: 6-Substituierte Pentafulvene (2a - d) verdrängen unter photochemischen Bedingungen aus Tricarbonyl(η6-8,8-dimethylheptafulven)chrom(0) (1) einen CO-Liganden unter Ausbildung einer C - C-Bindung zwischen C-6 eines Fulvens und C-1 des Heptafulven-Liganden. Es resultieren substituierte Dicarbonyl[η5:3-(cyclopentadiendiyl)(isopropylidencycloheptadiendiyl)methan]-chrom-Komplexe (3a - 5c), und zwar stets in zwei Diastereomeren, die sich säulenchromatographische trennen lassen. Sie unterscheiden sich in der Stellung des η3-Enyl-Systems. In 3a, d umfaßt das Enyl-System C-1′ bis C-3′, in 4a, b, d C-1′, C-7′ und C-8′ und in 5b, c C-3′ bis C-5′ im Isopropylidencycloheptadiendiyl-Rest. Die Konstitutionsformeln von 3a - 5c wurden spektroskopisch abgeleitet.
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