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  • Blackwell Publishing Ltd
  • Nature Publishing Group
  • 2015-2019  (44)
  • 1970-1974
  • 1955-1959  (6,019)
  • 1940-1944
  • 2018  (44)
  • 1959  (6,019)
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  • 2015-2019  (44)
  • 1970-1974
  • 1955-1959  (6,019)
  • 1940-1944
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  • 1
    Publication Date: 2018-09-20
    Description: Understanding how the Antarctic ice sheet will respond to global warming relies on knowledge of how it has behaved in the past. The use of numerical models, the only means to quantitatively predict the future, is hindered by limitations to topographic data both now and in the past, and in knowledge of how subsurface oceanic, glaciological and hydrological processes interact. Incorporating the variety and interplay of such processes, operating at multiple spatio-temporal scales, is critical to modeling the Antarctic’s system evolution and requires direct observations in challenging locations. As these processes do not observe disciplinary boundaries neither should our future research.
    Repository Name: EPIC Alfred Wegener Institut
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  • 2
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    Nature Publishing Group
    In:  EPIC3Nature Communication, Nature Publishing Group, 9(3178), ISSN: 2041-1723
    Publication Date: 2019-02-13
    Description: Natural dissolved organic matter (DOM) comprises a broad range of dissolved organic molecules in aquatic systems and is among the most complex molecular mixtures known. Here we show, by comparing detailed structural fingerprints of individual molecular formulae in DOM from a set of four marine and one freshwater environments, that a major component of DOM is molecularly indistinguishable in these diverse samples. Molecular conformity was not only apparent by the co-occurrence of thousands of identical molecular formulae, but also by identical structural features of those isomers that collectively represent a molecular formula. The presence of a large pool of compounds with identical structural features in DOM is likely the result of a cascade of degradation processes or common synthetic pathways that ultimately lead to the formation of a universal background, regardless of origin and history of the organic material. This novel insight impacts our understanding of long-term turnover of DOM as the underlying mechanisms are possibly universal.
    Repository Name: EPIC Alfred Wegener Institut
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  • 3
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    Nature Publishing Group
    In:  EPIC3Nature Protocols, Nature Publishing Group, 13(6), pp. 1310-1330, ISSN: 1754-2189
    Publication Date: 2020-02-23
    Description: Traditionally, the description of microorganisms starts with their isolation from an environmental sample. Many environmentally relevant anaerobic microorganisms grow very slowly, and often they rely on syntrophic interactions with other microorganisms. This impedes their isolation and characterization by classic microbiological techniques. We developed and applied an approach for the successive enrichment of syntrophic hydrocarbon-degrading microorganisms from environmental samples. We collected samples from microbial mat-covered hydrothermally heated hydrocarbon-rich sediments of the Guaymas Basin and mixed them with synthetic mineral medium to obtain sediment slurries. Supplementation with defined substrates (i.e., methane or butane), incubation at specific temperatures, and a regular maintenance procedure that included the measurement of metabolic products and stepwise dilutions enabled us to establish highly active, virtually sediment-free enrichment cultures of actively hydrocarbon-degrading communities in a 6-months to several-years' effort. Using methane as sole electron donor shifted the originally highly diverse microbial communities toward defined mixed cultures dominated by syntrophic consortia consisting of anaerobic methane-oxidizing archaea (ANME) and different sulfate-reducing bacteria. Cultivation with butane at 50 °C yielded consortia of archaea belonging to Candidatus Syntrophoarchaeum and Candidatus Desulfofervidus auxilii partner bacteria. This protocol also describes sampling for further molecular characterization of enrichment cultures by fluorescence in situ hybridization (FISH), and transcriptomics and metabolite analyses, which can provide insights into the functioning of hydrocarbon metabolism in archaea and resolve important mechanisms that enable electron transfer to their sulfate-reducing partner bacteria.
    Repository Name: EPIC Alfred Wegener Institut
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  • 4
    Publication Date: 2020-02-12
    Description: The construction of high capacity data sharing networks to support increasing government and commercial data exchange has highlighted a key roadblock: the content of existing Internet-connected information remains siloed due to a multiplicity of local languages and data dictionaries. This lack of a digital lingua franca is obvious in the domain of human food as materials travel from their wild or farm origin, through processing and distribution chains, to consumers. Well defined, hierarchical vocabulary, connected with logical relationships—in other words, an ontology—is urgently needed to help tackle data harmonization problems that span the domains of food security, safety, quality, production, distribution, and consumer health and convenience. FoodOn (http://foodon.org) is a consortium-driven project to build a comprehensive and easily accessible global farm-to-fork ontology about food, that accurately and consistently describes foods commonly known in cultures from around the world. FoodOn addresses food product terminology gaps and supports food traceability. Focusing on human and domesticated animal food description, FoodOn contains animal and plant food sources, food categories and products, and other facets like preservation processes, contact surfaces, and packaging. Much of FoodOn’s vocabulary comes from transforming LanguaL, a mature and popular food indexing thesaurus, into a World Wide Web Consortium (W3C) OWL Web Ontology Language-formatted vocabulary that provides system interoperability, quality control, and software-driven intelligence. FoodOn compliments other technologies facilitating food traceability, which is becoming critical in this age of increasing globalization of food networks.
    Repository Name: EPIC Alfred Wegener Institut
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  • 5
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 1287, doi:10.1038/s41467-018-03468-6.
    Description: Warm subtropical-origin Atlantic water flows northward across the Greenland-Scotland Ridge into the Nordic Seas, where it relinquishes heat to the atmosphere and gradually transforms into dense Atlantic-origin water. Returning southward along east Greenland, this water mass is situated beneath a layer of cold, fresh surface water and sea ice. Here we show, using measurements from autonomous ocean gliders, that the Atlantic-origin water was re-ventilated while transiting the western Iceland Sea during winter. This re-ventilation is a recent phenomenon made possible by the retreat of the ice edge toward Greenland. The fresh surface layer that characterises this region in summer is diverted onto the Greenland shelf by enhanced onshore Ekman transport induced by stronger northerly winds in fall and winter. Severe heat loss from the ocean offshore of the ice edge subsequently triggers convection, which further transforms the Atlantic-origin water. This re-ventilation is a counterintuitive occurrence in a warming climate, and highlights the difficulties inherent in predicting the behaviour of the complex coupled climate system.
    Description: Support for this work was provided by the Norwegian Research Council under Grant agreement no. 231647 (L.H. and K.V.), the Bergen Research Foundation under Grant BFS2016REK01 (K.V.), and the Centre for Climate Dynamics at the Bjerknes Centre through the FRESHWATER project (K.V.). Additional funding was provided by the Swiss National Science Foundation grants P2EZP2162267 and P300P2174307 (L.P.), the National Science Foundation grant OCE-1558742 (M.A.S.), the Norway Fulbright Foundation (K.V.), the Canada Fulbright Foundation (G.W.K.M.), and the Natural Sciences and Engineering Research Council of Canada (G.W.K.M.).
    Repository Name: Woods Hole Open Access Server
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  • 6
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4917, doi:10.1038/s41598-018-23167-y.
    Description: Intertidal inhabitants are exposed to the 24-hour solar day, and the 12.4 hour rising and falling of the tides. One or both of these cycles govern intertidal organisms’ behaviour and physiology, yet little is known about the molecular clockworks of tidal rhythmicity. Here, we show that the limpet Cellana rota exhibits robust tidally rhythmic behaviour and gene expression. We assembled a de-novo transcriptome, identifying novel tidal, along with known circadian clock genes. Surprisingly, most of the putative circadian clock genes, lack a typical rhythmicity. We identified numerous tidally rhythmic genes and pathways commonly associated with the circadian clock. We show that not only is the behaviour of an intertidal organism in tune with the tides, but so too are many of its genes and pathways. These findings highlight the plasticity of biological timekeeping in nature, strengthening the growing notion that the role of ‘canonical’ circadian clock genes may be more fluid than previously thought, as exhibited in an organism which has evolved in an environment where tidal oscillations are the dominant driving force.
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  • 7
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 8128, doi:10.1038/s41598-018-26484-4.
    Description: The kakapo is a critically endangered, herbivorous parrot endemic to New Zealand. The kakapo hindgut hosts a dense microbial community of low taxonomic diversity, typically dominated by Escherichia fergusonii, and has proven to be a remarkably stable ecosystem, displaying little variation in core membership over years of study. To elucidate mechanisms underlying this robustness, we performed 16S rRNA gene-based co-occurrence network analysis to identify potential interactions between E. fergusonii and the wider bacterial community. Genomic and metagenomic sequencing were employed to facilitate interpretation of potential interactions observed in the network. E. fergusonii maintained very few correlations with other members of the microbiota, and isolates possessed genes for the generation of energy from a wide range of carbohydrate sources, including plant fibres such as cellulose. We surmise that this dominant microorganism is abundant not due to ecological interaction with other members of the microbiota, but its ability to metabolise a wide range of nutrients in the gut. This research represents the first concerted effort to understand the functional roles of the kakapo microbiota, and leverages metagenomic data to contextualise co-occurrence patterns. By combining these two techniques we provide a means for studying the diversity-stability hypothesis in the context of bacterial ecosystems.
    Description: This work was supported by funding from the Department of Conservation (DOC) as well as a University of Auckland Faculty Research Development Fund grant (9841 3626187) to MWT, and a University of Auckland Doctoral Scholarship to DWW.
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  • 8
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 7363, doi:10.1038/s41598-018-25565-8.
    Description: Satellite-tracking of mature white sharks (Carcharodon carcharias) has revealed open-ocean movements spanning months and covering tens of thousands of kilometers. But how are the energetic demands of these active apex predators met as they leave coastal areas with relatively high prey abundance to swim across the open ocean through waters often characterized as biological deserts? Here we investigate mesoscale oceanographic variability encountered by two white sharks as they moved through the Gulf Stream region and Sargasso Sea in the North Atlantic Ocean. In the vicinity of the Gulf Stream, the two mature female white sharks exhibited extensive use of the interiors of clockwise-rotating anticyclonic eddies, characterized by positive (warm) temperature anomalies. One tagged white shark was also equipped with an archival tag that indicated this individual made frequent dives to nearly 1,000 m in anticyclones, where it was presumably foraging on mesopelagic prey. We propose that warm temperature anomalies in anticyclones make prey more accessible and energetically profitable to adult white sharks in the Gulf Stream region by reducing the physiological costs of thermoregulation in cold water. The results presented here provide valuable new insight into open ocean habitat use by mature, female white sharks that may be applicable to other large pelagic predators.
    Description: This work was supported by the WHOI Ocean Life Institute and awards from NASA and NSF.
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  • 9
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2398, doi:10.1038/s41467-018-04809-1.
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  • 10
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 10610, doi:10.1038/s41598-018-28871-3.
    Description: Foraminifera in sediments exposed to gas-hydrate dissociation are not expected to have cellular adaptations that facilitate inhabitation of chemosynthesis-based ecosystems because, to date, there are no known endemic seep foraminifera. To establish if foraminifera inhabit sediments impacted by gas-hydrate dissociation, we examined the cellular ultrastructure of Melonis barleeanus (Williamson, 1858) from the Vestnesa gas hydrate province (Arctic Ocean, west of Svalbard at ~79 °N; ~1200-m depth; n = 4). From sediments with gas hydrate indicators, living M. barleeanus had unusual pore plugs composed of a thick, fibrous meshwork; mitochondria were concentrated at the cell periphery, under pore plugs. While there was no evidence of endosymbioses with prokaryotes, most M. barleeanus specimens were associated with what appear to be Type I methanotrophic bacteria. One foraminifer had a particularly large bolus of these microbes concentrated near its aperture. This is the first documented instance of bona fide living M. barleeanus in gas-hydrate sediments and first documentation of a foraminifer living in close association with putative methanotrophs. Our observations have implications to paleoclimate records utilizing this foundational foraminiferal species.
    Description: JMB was funded by a WHOI Independent Study Award (Mellon Grant), with partial support from NSF grant OCE-1634469. GP and CAGE 15-2 cruise were supported by the Research Council of Norway through CAGE Center for Excellence in Arctic Gas Hydrate Environment and Climate project 223259 and NORCRUST (project number 255150).
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  • 11
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2809, doi:10.1038/s41467-018-05253-x.
    Description: Voltage-sensing (VSD) and cyclic nucleotide-binding domains (CNBD) gate ion channels for rapid electrical signaling. By contrast, solute carriers (SLCs) that passively redistribute substrates are gated by their substrates themselves. Here, we study the orphan sperm-specific solute carriers SLC9C1 that feature a unique tripartite structure: an exchanger domain, a VSD, and a CNBD. Voltage-clamp fluorimetry shows that SLC9C1 is a genuine Na+/H+ exchanger gated by voltage. The cellular messenger cAMP shifts the voltage range of activation. Mutations in the transport domain, the VSD, or the CNBD strongly affect Na+/H+ exchange, voltage gating, or cAMP sensitivity, respectively. Our results establish SLC9C1 as a phylogenetic chimaera that combines the ion-exchange mechanism of solute carriers with the gating mechanism of ion channels. Classic SLCs slowly readjust changes in the intra- and extracellular milieu, whereas voltage gating endows the Na+/H+ exchanger with the ability to produce a rapid pH response that enables downstream signaling events.
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  • 12
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 14955, doi:10.1038/s41598-018-33021-w.
    Description: Glomeruli are the functional units of olfactory information processing but little remains known about their individual unit function. This is due to their widespread activation by odor stimuli. We expressed channelrhodopsin-2 in a single olfactory sensory neuron type, and used laser stimulation and simultaneous in vivo calcium imaging to study the responses of a single glomerulus to optogenetic stimulation. Calcium signals in the neuropil of this glomerulus were representative of the sensory input and nearly identical if evoked by intensity-matched odor and laser stimuli. However, significantly fewer glomerular layer interneurons and olfactory bulb output neurons (mitral cells) responded to optogenetic versus odor stimuli, resulting in a small and spatially compact optogenetic glomerular unit response. Temporal features of laser stimuli were represented with high fidelity in the neuropil of the glomerulus and the mitral cells, but not in interneurons. Increases in laser stimulus intensity were encoded by larger signal amplitudes in all compartments of the glomerulus, and by the recruitment of additional interneurons and mitral cells. No spatial expansion of the glomerular unit response was observed in response to stronger input stimuli. Our data are among the first descriptions of input-output transformations in a selectively activated olfactory glomerulus.
    Description: Funded by the World Class Institute/National Research Foundation of Korea (KRF: WCI 2009-003) and NIH: DC005259 and NS099691 grants.
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  • 13
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15517, doi:10.1038/s41598-018-33610-9.
    Description: Subduction zones impose an important control on the geochemical cycling between the surficial and internal reservoirs of the Earth. Sulphur and carbon are transferred into Earth’s mantle by subduction of pelagic sediments and altered oceanic lithosphere. Release of oxidizing sulphate- and carbonate-bearing fluids modifies the redox state of the mantle and the chemical budget of subduction zones. Yet, the mechanisms of sulphur and carbon cycling within subduction zones are still unclear, in part because data are typically derived from arc volcanoes where fluid compositions are modified during transport through the mantle wedge. We determined the bulk rock elemental, and sulphur and carbon isotope compositions of exhumed ultramafic and metabasic rocks from Syros, Greece. Comparison of isotopic data with major and trace element compositions indicates seawater alteration and chemical exchange with sediment-derived fluids within the subduction zone channel. We show that small bodies of detached slab material are subject to metasomatic processes during exhumation, in contrast to large sequences of obducted ophiolitic sections that retain their seafloor alteration signatures. In particular, fluids circulating along the plate interface can cause sulphur mobilization during several stages of exhumation within high-pressure rocks. This takes place more pervasively in serpentinites compared to mafic rocks.
    Description: This project was supported by NSF-EAR grant 1324566 to E.M.S. and B.C.G., and NSF EAR award 1250470 to M.J.C. We acknowledge support by the German Research Foundation and the Open Access Publication Fund of the Freie Universität Berlin.
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  • 14
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 3077, doi:10.1038/s41467-018-05574-x.
    Description: Paleoclimate reconstructions are only as good as their chronology. In particular, different chronological assumptions for marine sediment cores can lead to different reconstructions of ocean ventilation age and atmosphere−ocean carbon exchange history. Here we build the first high-resolution chronology that is free of the dating uncertainties common in marine sediment records, based on radiocarbon dating twigs found with computed tomography scans in two cores from the Eastern Equatorial Pacific (EEP). With this accurate chronology, we show that the ventilation ages of the EEP thermocline and intermediate waters were similar to today during the Last Glacial Maximum and deglaciation, in contradiction with previous studies. Our results suggest that the glacial respired carbon pool in the EEP was not significantly older than today, and that the deglacial strengthening of the equatorial Pacific carbon source was probably driven by low-latitude processes rather than an increased subsurface supply of upwelled carbon from high-latitude oceans.
    Description: The lab work at NOSAMS was supported by Ocean Ventures Fund from WHOI and an NOSAMS graduate internship granted to N.Z
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  • 15
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15219, doi:10.1038/s41598-018-33283-4.
    Description: This Article corrects an error in Equation 1
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  • 16
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15740, doi:10.1038/s41598-018-33640-3.
    Description: Hurricanes passing over the ocean can mix the water column down to great depths and resuspend massive volumes of sediments on the continental shelves. Consequently, organic carbon and reduced inorganic compounds associated with these sediments can be resuspended from anaerobic portions of the seabed and re-exposed to dissolved oxygen (DO) in the water column. This process can drive DO consumption as sediments become oxidized. Previous studies have investigated the effect of hurricanes on DO in different coastal regions of the world, highlighting the alleviation of hypoxic conditions by extreme winds, which drive vertical mixing and re-aeration of the water column. However, the effect of hurricane-induced resuspended sediments on DO has been neglected. Here, using a diverse suite of datasets for the northern Gulf of Mexico, we find that in the few days after a hurricane passage, decomposition of resuspended shelf sediments consumes up to a fifth of the DO added to the bottom of the water column during vertical mixing. Despite uncertainty in this value, we highlight the potential significance of this mechanism for DO dynamics. Overall, sediment resuspension likely occurs over all continental shelves affected by tropical cyclones, potentially impacting global cycles of marine DO and carbon.
    Description: Support for J. Moriarty was provided by the USGS Mendenhall Program.
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  • 17
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2864, doi:10.1038/s41467-018-05313-2.
    Description: The mechanisms of transfer of crustal material from the subducting slab to the overlying mantle wedge are still debated. Mélange rocks, formed by mixing of sediments, oceanic crust, and ultramafics along the slab-mantle interface, are predicted to ascend as diapirs from the slab-top and transfer their compositional signatures to the source region of arc magmas. However, the compositions of melts that result from the interaction of mélanges with a peridotite wedge remain unknown. Here we present experimental evidence that melting of peridotite hybridized by mélanges produces melts that carry the major and trace element abundances observed in natural arc magmas. We propose that differences in nature and relative contributions of mélanges hybridizing the mantle produce a range of primary arc magmas, from tholeiitic to calc-alkaline. Thus, assimilation of mélanges into the wedge may play a key role in transferring subduction signatures from the slab to the source of arc magmas.
    Description: This project was supported by the WHOI Ocean Exploration Institute (OEI) 27071178 to V.L.R.; Previous related projects were supported by NSF EAR-1348063 and WHOI OEI to H.R.M.
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  • 18
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cell Death and Disease 9 (2018): 663, doi:10.1038/s41419-018-0704-9.
    Description: The poor regenerative capacity of descending neurons is one of the main causes of the lack of recovery after spinal cord injury (SCI). Thus, it is of crucial importance to find ways to promote axonal regeneration. In addition, the prevention of retrograde degeneration leading to the atrophy/death of descending neurons is an obvious prerequisite to activate axonal regeneration. Lampreys show an amazing regenerative capacity after SCI. Recent histological work in lampreys suggested that GABA, which is massively released after a SCI, could promote the survival of descending neurons. Here, we aimed to study if GABA, acting through GABAB receptors, promotes the survival and axonal regeneration of descending neurons of larval sea lampreys after a complete SCI. First, we used in situ hybridization to confirm that identifiable descending neurons of late-stage larvae express the gabab1 subunit of the GABAB receptor. We also observed an acute increase in the expression of this subunit in descending neurons after SCI, which further supported the possible role of GABA and GABAB receptors in promoting the survival and regeneration of these neurons. So, we performed gain and loss of function experiments to confirm this hypothesis. Treatments with GABA and baclofen (GABAB agonist) significantly reduced caspase activation in descending neurons 2 weeks after a complete SCI. Long-term treatments with GABOB (a GABA analogue) and baclofen significantly promoted axonal regeneration of descending neurons after SCI. These data indicate that GABAergic signalling through GABAB receptors promotes the survival and regeneration of descending neurons after SCI. Finally, we used morpholinos against the gabab1 subunit to knockdown the expression of the GABAB receptor in descending neurons. Long-term morpholino treatments caused a significant inhibition of axonal regeneration. This shows that endogenous GABA promotes axonal regeneration after a complete SCI in lampreys by activating GABAB receptors.
    Description: Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund 2007–2013 (Grant number: BFU2014-56300-P) and Xunta de Galicia (Grant number: GPC2014/030). D.R.-S. was supported by a fellowship from EMBO (Ref.: 7010) to carry out a short-term stay at the laboratory of JRM. A.B.-I. was supported by a grant from the Xunta de Galicia (Grant number: 2016-PG008) and a grant from the crowdfunding platform Precipita (FECYT; Spanish Ministry of Economy and Competitiveness; grant number 2017-CP081).
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  • 19
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2431, doi:10.1038/s41467-018-04421-3.
    Description: Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS.
    Description: This research was supported by the NSF Antarctic program through Award #1341630.
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  • 20
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 11997, doi:10.1038/s41598-018-30091-8.
    Description: The abundance of organic carbon (OC) in vegetation and soils (~2,600 PgC) compared to carbon in the atmosphere (~830 PgC) highlights the importance of terrestrial OC in global carbon budgets. The residence time of OC in continental reservoirs, which sets the rates of carbon exchange between land and atmosphere, represents a key uncertainty in global carbon cycle dynamics. Retention of terrestrial OC can also distort bulk OC- and biomarker-based paleorecords, yet continental storage timescales remain poorly quantified. Using “bomb” radiocarbon (14C) from thermonuclear weapons testing as a tracer, we model leaf-wax fatty acid and bulk OC 14C signatures in a river-proximal marine sediment core from the Bay of Bengal in order to constrain OC storage timescales within the Ganges-Brahmaputra (G-B) watershed. Our model shows that 79–83% of the leaf-waxes in this core were stored in continental reservoirs for an average of 1,000–1,200 calendar years, while the remainder was stored for an average of 15 years. This age structure distorts high-resolution organic paleorecords across geologically rapid events, highlighting that compound-specific proxy approaches must consider storage timescales. Furthermore, these results show that future environmental change could destabilize large stores of old - yet reactive - OC currently stored in tropical basins.
    Description: We acknowledge funding support from the Agouron Institute Postdoctoral Fellowship (K.L.F), the US National Science Foundation (Awards: OCE-1333387 and OCE-13333826), the Investment in Science Fund given primarily by WHOI Trustee and Corporation Members, and the Swiss National Science Foundation (Award: 200020_163162).
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  • 21
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 13478, doi:10.1038/s41598-018-31175-1.
    Description: Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N2O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha−1 yr−1 increased maize yield and N2O emissions only slightly. Unlike experiences in temperate regions, leached nitrate accumulated in deep soils with increased fertilizer and conversion to cropping at N fertilization rates 〉80 kg N ha−1, which exceeded maize demand. This raises new questions about the capacity of tropical agricultural soils to store nitrogen, which may determine when and how much nitrogen impacts surface waters.
    Description: This project was supported by grants from NSF (DEB-1257944, DEB-1257391, DEB1457017, EF-1541770, EF-1655432, EF-1519342, IOS-1660034, IOS-1457662, and EAR-1739724) to M. Macedo, C. Neill, and M.T. Coe.
    Repository Name: Woods Hole Open Access Server
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  • 22
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 10140, doi:10.1038/s41598-018-28455-1.
    Description: Haynesina germanica, an ubiquitous benthic foraminifer in intertidal mudflats, has the remarkable ability to isolate, sequester, and use chloroplasts from microalgae. The photosynthetic functionality of these kleptoplasts has been demonstrated by measuring photosystem II quantum efficiency and O2 production rates, but the precise role of the kleptoplasts in foraminiferal metabolism is poorly understood. Thus, the mechanism and dynamics of C and N assimilation and translocation from the kleptoplasts to the foraminiferal host requires study. The objective of this study was to investigate, using correlated TEM and NanoSIMS imaging, the assimilation of inorganic C and N (here ammonium, NH4+) in individuals of a kleptoplastic benthic foraminiferal species. H. germanica specimens were incubated for 20 h in artificial seawater enriched with H13CO3− and 15NH4+ during a light/dark cycle. All specimens (n = 12) incorporated 13C into their endoplasm stored primarily in the form of lipid droplets. A control incubation in darkness resulted in no 13C-uptake, strongly suggesting that photosynthesis is the process dominating inorganic C assimilation. Ammonium assimilation was observed both with and without light, with diffuse 15N-enrichment throughout the cytoplasm and distinct 15N-hotspots in fibrillar vesicles, electron-opaque bodies, tubulin paracrystals, bacterial associates, and, rarely and at moderate levels, in kleptoplasts. The latter observation might indicate that the kleptoplasts are involved in N assimilation. However, the higher N assimilation observed in the foraminiferal endoplasm incubated without light suggests that another cytoplasmic pathway is dominant, at least in darkness. This study clearly shows the advantage provided by the kleptoplasts as an additional source of carbon and provides observations of ammonium uptake by the foraminiferal cell.
    Description: This work was supported by the Swiss National Science Foundation (grant no. 200021_149333) and was part of the CNRS EC2CO-Lefe project ForChlo. It was also supported by the Region Pays de la Loire (Post-doc position of TJ, on FRESCO project) as well as the WHOI Robert W. Morse Chair for Excellence in Oceanography and The Investment in Science Fund at WHOI.
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  • 23
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 13556, doi:10.1038/s41598-018-31710-0.
    Description: In mammals, a complex array of oral sensors assess the taste, temperature and haptic properties of food. Although the representation of taste has been extensively studied in the gustatory cortex, it is unclear how the somatosensory cortex encodes information about the properties of oral stimuli. Moreover, it is poorly understood how different oral sensory modalities are integrated and how sensory responses are translated into oral motor actions. To investigate whether oral somatosensory cortex processes food-related sensations and movements, we performed in vivo whole-cell recordings and motor mapping experiments in rats. Neurons in oral somatosensory cortex showed robust post-synaptic and sparse action potential responses to air puffs. Membrane potential showed that cold water evoked larger responses than room temperature or hot water. Most neurons showed no clear tuning of responses to bitter, sweet and neutral gustatory stimuli. Finally, motor mapping experiments with histological verification revealed an initiation of movements related to food consumption behavior, such as jaw opening and tongue protrusions. We conclude that somatosensory cortex: (i) provides a representation of the temperature of oral stimuli, (ii) does not systematically encode taste information and (iii) influences orofacial movements related to food consummatory behavior.
    Description: This work was supported by the Marine Biological Laboratory, Humboldt Universität zu Berlin and Neurocure.
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  • 24
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 3500, doi:10.1038/s41467-018-05804-2.
    Description: Subduction zone magmas are more oxidised on eruption than those at mid-ocean ridges. This is attributed either to oxidising components, derived from subducted lithosphere (slab) and added to the mantle wedge, or to oxidation processes occurring during magma ascent via differentiation. Here we provide direct evidence for contributions of oxidising slab agents to melts trapped in the sub-arc mantle. Measurements of sulfur (S) valence state in sub-arc mantle peridotites identify sulfate, both as crystalline anhydrite (CaSO4) and dissolved SO42− in spinel-hosted glass (formerly melt) inclusions. Copper-rich sulfide precipitates in the inclusions and increased Fe3+/∑Fe in spinel record a S6+–Fe2+ redox coupling during melt percolation through the sub-arc mantle. Sulfate-rich glass inclusions exhibit high U/Th, Pb/Ce, Sr/Nd and δ34S (+ 7 to + 11‰), indicating the involvement of dehydration products of serpentinised slab rocks in their parental melt sources. These observations provide a link between liberated slab components and oxidised arc magmas.
    Description: We acknowledge financial support by the Australian Research Council (DE120100513 and DP120104240) and the ESRF for beam time (EC1061 and ES238).
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  • 25
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 9478, doi:10.1038/s41598-018-26948-7.
    Description: Tidal wetlands produce long-term soil organic carbon (C) stocks. Thus for carbon accounting purposes, we need accurate and precise information on the magnitude and spatial distribution of those stocks. We assembled and analyzed an unprecedented soil core dataset, and tested three strategies for mapping carbon stocks: applying the average value from the synthesis to mapped tidal wetlands, applying models fit using empirical data and applied using soil, vegetation and salinity maps, and relying on independently generated soil carbon maps. Soil carbon stocks were far lower on average and varied less spatially and with depth than stocks calculated from available soils maps. Further, variation in carbon density was not well-predicted based on climate, salinity, vegetation, or soil classes. Instead, the assembled dataset showed that carbon density across the conterminous united states (CONUS) was normally distributed, with a predictable range of observations. We identified the simplest strategy, applying mean carbon density (27.0 kg C m−3), as the best performing strategy, and conservatively estimated that the top meter of CONUS tidal wetland soil contains 0.72 petagrams C. This strategy could provide standardization in CONUS tidal carbon accounting until such a time as modeling and mapping advancements can quantitatively improve accuracy and precision.
    Description: Synthesis efforts were funded by NASA Carbon Monitoring System (CMS; NNH14AY67I), USGS LandCarbon and the Smithsonian Institution. J.R.H. was additionally supported by the NSF-funded Coastal Carbon Research Coordination Network while completing this manuscript (DEB-1655622). J.M.S. coring efforts were funded by NSF (EAR-1204079). B.P.H. coring efforts were funded by Earth Observatory (Publication Number 197).
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  • 26
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Communications Biology 1 (2018): 177, doi:10.1038/s42003-018-0183-7.
    Description: The oceans are warming and coral reefs are bleaching with increased frequency and severity, fueling concerns for their survival through this century. Yet in the central equatorial Pacific, some of the world’s most productive reefs regularly experience extreme heat associated with El Niño. Here we use skeletal signatures preserved in long-lived corals on Jarvis Island to evaluate the coral community response to multiple successive heatwaves since 1960. By tracking skeletal stress band formation through the 2015-16 El Nino, which killed 95% of Jarvis corals, we validate their utility as proxies of bleaching severity and show that 2015-16 was not the first catastrophic bleaching event on Jarvis. Since 1960, eight severe (〉30% bleaching) and two moderate (〈30% bleaching) events occurred, each coinciding with El Niño. While the frequency and severity of bleaching on Jarvis did not increase over this time period, 2015–16 was unprecedented in magnitude. The trajectory of recovery of this historically resilient ecosystem will provide critical insights into the potential for coral reef resilience in a warming world.
    Description: Funding for this study was provided by National Science Foundation awards OCE 1537338, OCE 1605365, and OCE 1031971 to A.L.C., and the Robertson Foundation to A.L.C., National Science Foundation Graduate Research Fellowships to T.M.D. and A.E.A., and a National Defense Science and Engineering Graduate Fellowship to H.E.R.
    Repository Name: Woods Hole Open Access Server
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  • 27
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 17437, doi:10.1038/s41598-018-35309-3.
    Description: During recent years, rapid seasonal growth of macroalgae covered extensive areas within the Yellow Sea, developing the world’s most spatially extensive “green tide”. The remarkably fast accumulation of macroalgal biomass is the joint result of high nitrogen supplies in Yellow Sea waters, plus ability of the macroalgae to optionally use C4 photosynthetic pathways that facilitate rapid growth. Stable isotopic evidence shows that the high nitrogen supply is derived from anthropogenic sources, conveyed from watersheds via river discharges, and by direct atmospheric deposition. Wastewater and manures supply about half the nitrogen used by the macroalgae, fertiliser and atmospheric deposition each furnish about a quarter of the nitrogen in macroalgae. The massive green tides affecting the Yellow Sea are likely to increase, with significant current and future environmental and human consequences. Addressing these changing trajectories will demand concerted investment in new basic and applied research as the basis for developing management policies.
    Description: This work was supported by the State Key Project of Research and Development Plan (2016YFC1402106).
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  • 28
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 5179, doi:10.1038/s41467-018-07346-z.
    Description: Sunlight is the dominant control on phytoplankton biosynthetic activity, and darkness deprives them of their primary external energy source. Changes in the biochemical composition of phytoplankton communities over diel light cycles and attendant consequences for carbon and energy flux in environments remain poorly elucidated. Here we use lipidomic data from the North Pacific subtropical gyre to show that biosynthesis of energy-rich triacylglycerols (TAGs) by eukaryotic nanophytoplankton during the day and their subsequent consumption at night drives a large and previously uncharacterized daily carbon cycle. Diel oscillations in TAG concentration comprise 23 ± 11% of primary production by eukaryotic nanophytoplankton representing a global flux of about 2.4 Pg C yr−1. Metatranscriptomic analyses of genes required for TAG biosynthesis indicate that haptophytes and dinoflagellates are active members in TAG production. Estimates suggest that these organisms could contain as much as 40% more calories at sunset than at sunrise due to TAG production.
    Description: This work was supported by a grant from the Simons Foundation, and is a contribution of the Simons Collaboration on Ocean Processes and Ecology (SCOPE award # 329108, B.A.S.V.M.). K.W.B. was further supported by the Postdoctoral Scholarship Program at Woods Hole Oceanographic Institution & U.S. Geological Survey.
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  • 29
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 4702, doi:10.1038/s41467-018-07076-2.
    Description: The orbital-scale timing of South Asian monsoon (SAM) precipitation is poorly understood. Here we present new SST and seawater δ18O (δ18Osw) records from the Bay of Bengal, the core convective region of the South Asian monsoon, over the past 1 million years. Our records reveal that SAM precipitation peaked in the precession band ~9 kyrs after Northern Hemisphere summer insolation maxima, in phase with records of SAM winds in the Arabian Sea and eastern Indian Ocean. Precession-band variance, however, accounts for ~30% of the total variance of SAM precipitation while it was either absent or dominant in records of the East Asian monsoon (EAM). This and the observation that SAM precipitation was phase locked with obliquity minima and was sensitive to Southern Hemisphere warming provides clear evidence that SAM and EAM precipitation responded differently to orbital forcing and highlights the importance of internal processes forcing monsoon variability.
    Description: This study was partly funded by the German Science Foundation, DFG, IODP Priority Program (grant HA 5751/3-1).
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  • 30
    Publication Date: 2019-10-24
    Description: Conduit geometry affects magma ascent dynamics and, consequently, the style and evolution of volcanic eruptions. However, despite geological evidences support the occurrence of conduit widening during most volcanic eruptions, the factors controlling conduit enlargement are still unclear, and the effects of syn-eruptive variations of conduit geometry have not been investigated in depth yet. Based on numerical modeling and the application of appropriate stability criteria, we found out a strong relationship between magma rheology and conduit stability, with significant effects on eruptive dynamics. Indeed, in order to be stable, conduits feeding dacitic/rhyolitic eruptions need larger diameters respect to their phonolitic/trachytic counterparts, resulting in the higher eruption rates commonly observed in dacitic/rhyolitic explosive events. Thus, in addition to magma source conditions and viscosity-dependent efficiency for outgassing, we suggest that typical eruption rates for different magma types are also controlled by conduit stability. Results are consistent with a compilation of volcanological data and selected case studies. As stability conditions are not uniform along the conduit, widening is expected to vary in depth, and three axisymmetric geometries with depth-dependent radii were investigated. They are able to produce major modifications in eruptive parameters, suggesting that eruptive dynamics is influenced by syn-eruptive changes in conduit geometry.
    Description: Published
    Description: 4125
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Volcanology ; Magma Ascent ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2022-08-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4494, doi:10.1038/s41598-018-22758-z.
    Description: Six velocity sections straddling Cape Hatteras show a deep counterflow rounding the Cape wedged beneath the poleward flowing Gulf Stream and the continental slope. This counterflow is likely the upper part of the equatorward-flowing Deep Western Boundary Current (DWBC). Hydrographic data suggest that the equatorward flow sampled by the shipboard 38 kHz ADCP comprises the Upper Labrador Sea Water (ULSW) layer and top of the Classical Labrador Sea Water (CLSW) layer. Continuous DWBC flow around the Cape implied by the closely-spaced velocity sections here is also corroborated by the trajectory of an Argo float. These findings contrast with previous studies based on floats and tracers in which the lightest DWBC constituents did not follow the boundary to cross under the Gulf Stream at Cape Hatteras but were diverted into the interior as the DWBC encountered the Gulf Stream in the crossover region. Additionally, our six quasi-synoptic velocity sections confirm that the Gulf Stream intensified markedly at that time as it approached the separation point and flowed into deeper waters. Downstream increases were observed not only in the poleward transport across the sections but also in the current’s maximum speed.
    Description: This research was supported by NSF through OCE-1558521 and OCE-1332667 and by a grant from North Carolina to the Renewable Ocean Energy Program.
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  • 32
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 660, doi:10.1038/s41467-018-02984-9.
    Description: Efforts to estimate the physical and economic impacts of future climate change face substantial challenges. To enrich the currently popular approaches to impact analysis—which involve evaluation of a damage function or multi-model comparisons based on a limited number of standardized scenarios—we propose integrating a geospatially resolved physical representation of impacts into a coupled human-Earth system modeling framework. Large internationally coordinated exercises cannot easily respond to new policy targets and the implementation of standard scenarios across models, institutions and research communities can yield inconsistent estimates. Here, we argue for a shift toward the use of a self-consistent integrated modeling framework to assess climate impacts, and discuss ways the integrated assessment modeling community can move in this direction. We then demonstrate the capabilities of such a modeling framework by conducting a multi-sectoral assessment of climate impacts under a range of consistent and integrated economic and climate scenarios that are responsive to new policies and business expectations.
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  • 33
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 3926, doi:10.1038/s41598-018-22313-w.
    Description: Despite concerted international effort to track and interpret shifts in the abundance and distribution of Adélie penguins, large populations continue to be identified. Here we report on a major hotspot of Adélie penguin abundance identified in the Danger Islands off the northern tip of the Antarctic Peninsula (AP). We present the first complete census of Pygoscelis spp. penguins in the Danger Islands, estimated from a multi-modal survey consisting of direct ground counts and computer-automated counts of unmanned aerial vehicle (UAV) imagery. Our survey reveals that the Danger Islands host 751,527 pairs of Adélie penguins, more than the rest of AP region combined, and include the third and fourth largest Adélie penguin colonies in the world. Our results validate the use of Landsat medium-resolution satellite imagery for the detection of new or unknown penguin colonies and highlight the utility of combining satellite imagery with ground and UAV surveys. The Danger Islands appear to have avoided recent declines documented on the Western AP and, because they are large and likely to remain an important hotspot for avian abundance under projected climate change, deserve special consideration in the negotiation and design of Marine Protected Areas in the region.
    Description: We gratefully acknowledge the financial support of the Dalio Foundation, Inc. through the Dalio Explore Fund, which provided all the financing for the Danger Island Expedition. We would like to thank additional support for analysis from the National Science Foundation (NSF PLR&GSS 1255058 - H.J.L. and P.M.; NSF PLR 1443585 – M.J.P.) and the National Aeronautical and Space Administration (NNX14AC32G; H.J.L. and M.S.). Geospatial support for the analysis of high resolution satellite imagery provided by the Polar Geospatial Center under NSF PLR awards 1043681 & 1559691.
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  • 34
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 115, doi:10.1038/s41598-017-00091-1.
    Description: Mutations in Fused in Sarcoma/Translocated in Liposarcoma (FUS) cause familial forms of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by progressive axonal degeneration mainly affecting motor neurons. Evidence from transgenic mouse models suggests mutant forms of FUS exert an unknown gain-of-toxic function in motor neurons, but mechanisms underlying this effect remain unknown. Towards this end, we studied the effect of wild type FUS (FUS WT) and three ALS-linked variants (G230C, R521G and R495X) on fast axonal transport (FAT), a cellular process critical for appropriate maintenance of axonal connectivity. All ALS-FUS variants impaired anterograde and retrograde FAT in squid axoplasm, whereas FUS WT had no effect. Misfolding of mutant FUS is implicated in this process, as the molecular chaperone Hsp110 mitigated these toxic effects. Interestingly, mutant FUS-induced impairment of FAT in squid axoplasm and of axonal outgrowth in mammalian primary motor neurons involved aberrant activation of the p38 MAPK pathway, as also reported for ALS-linked forms of Cu, Zn superoxide dismutase (SOD1). Accordingly, increased levels of active p38 MAPK were detected in post-mortem human ALS-FUS brain tissues. These data provide evidence for a novel gain-of-toxic function for ALS-linked FUS involving p38 MAPK activation.
    Description: We are grateful for funding from NIH/NINDS (R01 NS078145, R01 NS090352, and R21 NS091860 to D.A.B., R01 NS066942A and R21 NS096642 to G.M., R01NS023868 and R01NS041170 to S.T.B.), the ALS Therapy Alliance/CVS Pharmacy (to D.A.B. and G.M.) and the ALS Association (to C.F. and J.M.).
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  • 35
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 1124, doi:10.1038/s41467-018-03134-x.
    Description: The ocean’s role in global climate change largely depends on its heat transport. Therefore, understanding the oceanic meridional heat transport (MHT) variability is a fundamental issue. Prevailing observational and modeling evidence suggests that MHT variability is primarily determined by the large-scale ocean circulation. Here, using new in situ observations in the eastern subpolar North Atlantic Ocean and an eddy-resolving numerical model, we show that energetic mesoscale eddies with horizontal scales of about 10–100 km profoundly modulate MHT variability on time scales from intra-seasonal to interannual. Our results reveal that the velocity changes due to mesoscale processes produce substantial variability for the MHT regionally (within sub-basins) and the subpolar North Atlantic as a whole. The findings have important implications for understanding the mechanisms for poleward heat transport variability in the subpolar North Atlantic Ocean, a key region for heat and carbon sequestration, ice–ocean interaction, and biological productivity.
    Description: J.Z. was financially supported by the Postdoctoral Scholar Program at WHOI, with funding provided by the Ocean and Climate Change Institute. This work was also supported by the US National Science Foundation (OCE-1258823 and OCE-1634886), as well as by China’s national key research and development projects (2016YFA0601803), the National Natural Science Foundation of China (41521091 and U1606402), the Qingdao National Laboratory for Marine Science and Technology (2015ASKJ01), and the Fundamental Research Funds for the Central Universities (201424001 and 201362048).
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  • 36
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 742, doi:10.1038/s41598-017-18757-1.
    Description: In mammals, spinal cord injury (SCI) leads to dramatic losses in neurons and synaptic connections, and consequently function. Unlike mammals, lampreys are vertebrates that undergo spontaneous regeneration and achieve functional recovery after SCI. Therefore our goal was to determine the complete transcriptional responses that occur after SCI in lampreys and to identify deeply conserved pathways that promote regeneration. We performed RNA-Seq on lamprey spinal cord and brain throughout the course of functional recovery. We describe complex transcriptional responses in the injured spinal cord, and somewhat surprisingly, also in the brain. Transcriptional responses to SCI in lampreys included transcription factor networks that promote peripheral nerve regeneration in mammals such as Atf3 and Jun. Furthermore, a number of highly conserved axon guidance, extracellular matrix, and proliferation genes were also differentially expressed after SCI in lampreys. Strikingly, ~3% of differentially expressed transcripts belonged to the Wnt pathways. These included members of the Wnt and Frizzled gene families, and genes involved in downstream signaling. Pharmacological inhibition of Wnt signaling inhibited functional recovery, confirming a critical role for this pathway. These data indicate that molecular signals present in mammals are also involved in regeneration in lampreys, supporting translational relevance of the model.
    Description: We gratefully acknowledge support from the National Institutes of Health (R03NS078519 to OB; R01GM104123 to JJS; R01NS078165 to JRM), The Feinstein Institute for Medical Research and The Marine Biological Laboratory, including the Charles Evans Foundation Research Award, the Albert and Ellen Grass Foundation Faculty Research Award, and The Eugene and Millicent Bell Fellowship Fund in Tissue Engineering.
    Keywords: Computational biology and bioinformatics ; Gene expression ; Spinal cord injury
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  • 37
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 266, doi:10.1038/s41467-017-02571-4.
    Description: Because microbial plankton in the ocean comprise diverse bacteria, algae, and protists that are subject to environmental forcing on multiple spatial and temporal scales, a fundamental open question is to what extent these organisms form ecologically cohesive communities. Here we show that although all taxa undergo large, near daily fluctuations in abundance, microbial plankton are organized into clearly defined communities whose turnover is rapid and sharp. We analyze a time series of 93 consecutive days of coastal plankton using a technique that allows inference of communities as modular units of interacting taxa by determining positive and negative correlations at different temporal frequencies. This approach shows both coordinated population expansions that demarcate community boundaries and high frequency of positive and negative associations among populations within communities. Our analysis thus highlights that the environmental variability of the coastal ocean is mirrored in sharp transitions of defined but ephemeral communities of organisms.
    Description: This work was supported by grants from the U.S. National Science Foundation (OCE-1441943) to M.F.P. and the U.S. Department of Energy (DE-SC0008743) to M.F.P. and E.J.A. A.M.M.-P. was partially supported by the Ramon Areces foundation through a postdoctoral fellowship. D.J.M. was supported by the U.S. National Science Foundation (OCE-1314642) and National Institute of Environmental Health Sciences (1P01ES021923-01) through the Woods Hole Center for Oceans and Human Health.
    Keywords: Marine biology ; Microbial ecology
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  • 38
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 121, doi:10.1038/s41467-017-02504-1.
    Description: Sediments in deep ocean trenches may contain crucial information on past earthquake history and constitute important sites of carbon burial. Here we present 14C data on bulk organic carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation for a core retrieved from the 〉7.5 km-deep Japan Trench. High-resolution 14C measurements, coupled with distinctive thermogram characteristics of OC, reveal hemipelagic sedimentation interrupted by episodic deposition of pre-aged OC in the trench. Low δ13C values and diverse 14C ages of thermal fractions imply that the latter material originates from the adjacent margin, and the co-occurrence of pre-aged OC with intervals corresponding to known earthquake events implies tectonically triggered, gravity-flow-driven supply. We show that 14C ages of thermal fractions can yield valuable chronological constraints on sedimentary sequences. Our findings shed new light on links between tectonically driven sedimentological processes and marine carbon cycling, with implications for carbon dynamics in hadal environments.
    Description: This study is supported by Doc.Mobility Fellowship (P1EZP2_159064) (R.B.) from the Swiss National Science Foundation (SNSF). This work is also supported by SNF “CAPS-LOCK” project 200021_140850 (T.I.E.), by SNSF grant (133481) (M.S.), and Austrian Science Foundation (P 29678-N28) (M.S.).
    Keywords: Carbon cycle ; Sedimentology
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  • 39
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4547, doi:10.1038/s41598-018-22732-9.
    Description: The assembly of membranous extensions such as microvilli and cilia in polarized cells is a tightly regulated, yet poorly understood, process. Peptidylglycine α-amidating monooxygenase (PAM), a membrane enzyme essential for the synthesis of amidated bioactive peptides, was recently identified in motile and non-motile (primary) cilia and has an essential role in ciliogenesis in Chlamydomonas, Schmidtea and mouse. In mammalian cells, changes in PAM levels alter secretion and organization of the actin cytoskeleton. Here we show that lack of Pam in zebrafish recapitulates the lethal edematous phenotype observed in Pam−/− mice and reveals additional defects. The pam−/− zebrafish embryos display an initial striking loss of microvilli and subsequently impaired ciliogenesis in the pronephros. In multiciliated mouse tracheal epithelial cells, vesicular PAM staining colocalizes with apical actin, below the microvilli. In PAM-deficient Chlamydomonas, the actin cytoskeleton is dramatically reorganized, and expression of an actin paralogue is upregulated. Biochemical assays reveal that the cytosolic PAM C-terminal domain interacts directly with filamentous actin but does not alter the rate of actin polymerization or disassembly. Our results point to a critical role for PAM in organizing the actin cytoskeleton during development, which could in turn impact both microvillus formation and ciliogenesis.
    Description: This study was supported by grants DK032949 (to BAE and REM), DK044464 (to JDG) and GM051293 (to SMK) from the National Institutes of Health.
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  • 40
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 12 (2018): 1-16, doi:10.1038/ismej.2017.187.
    Description: The rock-hosted subseafloor crustal aquifer harbors a reservoir of microbial life that may influence global marine biogeochemical cycles. Here we utilized metagenomic libraries of crustal fluid samples from North Pond, located on the flanks of the Mid-Atlantic Ridge, a site with cold, oxic subseafloor fluid circulation within the upper basement to query microbial diversity. Twenty-one samples were collected during a 2-year period to examine potential microbial metabolism and community dynamics. We observed minor changes in the geochemical signatures over the 2 years, yet the microbial community present in the crustal fluids underwent large shifts in the dominant taxonomic groups. An analysis of 195 metagenome-assembled genomes (MAGs) were generated from the data set and revealed a connection between litho- and autotrophic processes, linking carbon fixation to the oxidation of sulfide, sulfur, thiosulfate, hydrogen, and ferrous iron in members of the Proteobacteria, specifically the Alpha-, Gamma- and Zetaproteobacteria, the Epsilonbacteraeota and the Planctomycetes. Despite oxic conditions, analysis of the MAGs indicated that members of the microbial community were poised to exploit hypoxic or anoxic conditions through the use of microaerobic cytochromes, such as cbb3- and bd-type cytochromes, and alternative electron acceptors, like nitrate and sulfate. Temporal and spatial trends from the MAGs revealed a high degree of functional redundancy that did not correlate with the shifting microbial community membership, suggesting functional stability in mediating subseafloor biogeochemical cycles. Collectively, the repeated sampling at multiple sites, together with the successful binning of hundreds of genomes, provides an unprecedented data set for investigation of microbial communities in the cold, oxic crustal aquifer.
    Description: This work was supported by NSF OCE1062006 to JAH and NSF OCE1061827 to BTG. The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. The Center for Dark Energy Biosphere Investigations (C-DEBI) (OCE-0939564), a National Science Foundation-funded Science and Technology Centers of Excellence also supported the participation of CGW, JAH and BJT.
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  • 41
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 209, doi:10.1038/s41467-017-02105-y.
    Description: Correction to: Nature Communications 8:172 https://doi.org/10.1038/s41467-017-00197-0; Article published online: 2 August 2017
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  • 42
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 305, doi:10.1038/s41467-017-02701-y.
    Description: Correction to: Nature Communications https://doi.org/10.1038/s41467-017-01229-5, Article published online 07 November 2017
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  • 43
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 12 (2018): 237–252, doi:10.1038/ismej.2017.165.
    Description: Temperate coastal marine environments are replete with complex biotic and abiotic interactions that are amplified during spring and summer phytoplankton blooms. During these events, heterotrophic bacterioplankton respond to successional releases of dissolved organic matter as algal cells are lysed. Annual seasonal shifts in the community composition of free-living bacterioplankton follow broadly predictable patterns, but whether similar communities respond each year to bloom disturbance events remains unknown owing to a lack of data sets, employing high-frequency sampling over multiple years. We capture the fine-scale microdiversity of these events with weekly sampling using a high-resolution method to discriminate 16S ribosomal RNA gene amplicons that are 〉99% identical. Furthermore, we used 2 complete years of data to facilitate identification of recurrent sub-networks of co-varying microbes. We demonstrate that despite inter-annual variation in phytoplankton blooms and despite the dynamism of a coastal–oceanic transition zone, patterns of microdiversity are recurrent during both bloom and non-bloom conditions. Sub-networks of co-occurring microbes identified reveal that correlation structures between community members appear quite stable in a seasonally driven response to oligotrophic and eutrophic conditions.
    Description: PLB is supported by the European Research Council Advanced Investigator grant ABYSS 294757 to Antje Boetius. AF-G is supported by the European Union’s Horizon 2020 research and innovation program (Blue Growth: Unlocking the potential of Seas and Oceans) under grant agreement no. (634486) (project acronym INMARE). This study was funded by the Max Planck Society. Further support by the Department of Energy Joint Genome Institute (CSP COGITO) and DFG (FOR2406) is acknowledged by HT (TE 813/2-1) and RA (Am 73/9-1).
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  • 44
    Publication Date: 2022-12-22
    Description: Infections arising from multidrug-resistant pathogenic bacteria are spreading rapidly throughout the world and threaten to become untreatable. The origins of resistance are numerous and complex, but one underlying factor is the capacity of bacteria to rapidly export drugs through the intrinsic activity of efflux pumps. In this Review, we describe recent advances that have increased our understanding of the structures and molecular mechanisms of multidrug efflux pumps in bacteria. Clinical and laboratory data indicate that efflux pumps function not only in the drug extrusion process but also in virulence and the adaptive responses that contribute to antimicrobial resistance during infection. The emerging picture of the structure, function and regulation of efflux pumps suggests opportunities for countering their activities.
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  • 45
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Ten new species of colorless Eugleninae are described. One of them is the type of a new genus (Calycimonas physaloides nov. gen. nov. sp.). Especially remarkable forms are: Astasia acus, a species related to the green Euglena acus but without chromatophores and stigma and considerably smaller; Astasia edax, a species with animal-like nutrition and peculiar ecological adaptations; Petalomonas striata, a form which is not spirally but transversely striated; and finally Hyalophacus caecus, which was observed already by Klebs and Pochmann but was not sufficiently described. The new genus Calycimonas (ex fam. Peranemacearum) is related to Tropidoscyphus on the one hand (nearly the same shape as e.g. Tr. octocostatus, but possessing only a single flagellum) and to Petalomonas on the other hand (mode of nutrition and of swimming, formation of the reservoir, rigidity: however in transverse section not flattened).The Astasiae with zootrophic nutrition are collected in a new subgenus Astasiae devorantes or Phytophaga which comprises besides A. edax three species already described by Skuja.
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  • 46
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Topics: Biology
    Notes: SYNOPSIS. H. canis (James) is reported from three of 36 stray dogs at Singapore and one of 34 palm civets (Paradoxurus hermaphroditus Pallas) from Jeram, Selangor. H. muris (Balfour) was found at Singapore in 10 of 61 examples of Rattus norvegicus (Erxleben) and five of 23 of R. rattus diardi (Jentinck), and is also recorded from six of 139 examples of R. r. jarak (Bonhote) from Pulau Jarak, Straits of Malacca. Neutrophils of P. hermaphroditus containing gametocytes of H. canis exhibit pronounced karyorrhexis, while most of the parasites themselves show signs of pyknosis.
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  • 47
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Topics: Biology
    Notes: SYNOPSIS. A total of 155 clones of Stylonychia putrina collected in nature were tested for mating type. Two sexually isolated varieties were found among them: Variety I with 12 mating types and Var. II with 11. Five of the clones isolated in the laboratory belonged to 3 additional mating types of Var. I making a total of 15 mating types in this variety.Crosses were made among 6 of the mating types of Var. I, and 114 clones of progeny were raised and tested for mating type. No simple genetic explanation of the results was evident.An abnormal type of conjugation with fusion of the conjugants and subsequent fission was studied. Both parental mating types sometimes segregated during the first two fissions of a fused animal. Mating type determination in the progeny of the fused animals seemed to parallel that of the progeny of the normal conjugants in that in both cases certain mating types tended to be dominant over others.
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  • 48
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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  • 49
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. The cytochemical procedure of Sen was used to demonstrate urease activity in Tetrahymena pyriformis S.
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  • 50
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Topics: Biology
    Notes: SYNOPSIS. The chimpanzee is shown to behave like man to infection with Babesia divergens or bovis: the intact animal is totally resistant, whereas the splenectomized animal develops a fulminating infection accompanied by blackwater. The splenectomized rhesus monkey reacts in the same way also, but splenectomized rabbits are insusceptible. In the chimpanzee the typical accolé position of the “divergens” organisms (as seen in cattle) is absent, but occurs in the rhesus. It is suggested that latent piroplasmosis in man may exist on a large scale in rural populations in infected localities.
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  • 51
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Notes: SYNOPSIS. Studies cf 3 conjugating strains of Tetrahymena pyriformis grown in a bacterized medium indicated the presence of a system of alternative immobilizing surface antigens. Each strain was found to have the potential for the expression of 3 serologically unrelated antigens. These consisted of a “high temperature” antigen (expressed in the range of 20–35d̀C), a “low temperature” antigen (exhibited in cultures at 10d̀), and an antigen induced by growth in the presence of the above-mentioned “high temperature” antiserum. Normally, by the immobilization reaction, only one of these antigens could be detected as present on any one organism at any given time. The “high temperature” antigens of two of the strains were serclogically related while that of the 3rd strain did not cross-react with antisera to the other two. The “low temperature” antigens of the 3 strains were serologically related as were the antigens induced by growth in antiserum.Studies of inbred hybrids of two of the strains indicated a potential for still more alternative antigens as well as for the spontaneous expression of the antigen which in the parental strains could only be induced to appear by the presence of the specific antiserum.Study of the 3 strains in axenic medium indicated the existence of a more complex system and the possibility that two or more immobilizing antigens may be present simultaneously.
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  • 52
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    Topics: Biology
    Notes: SYNOPSIS. The establishment of Eimeria tenella sporozoites in the cecal mucosa of the chicken is described. The invasion process was similar to that reported for E. necatrix by Van Doorninck and Becker. Sporozoites were found to pass through the surface epithelium of the cecal mucosa into the lamina propria. Within the lamina propria the sporozoites were engulfed by macrophages and transported to the cells of the glands of Lieberkühn. Development of the sporozoites ensues within the gland epithelium.
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  • 53
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    Topics: Biology
    Notes: SYNOPSIS. The morphology of the vegetative phase and the sexual process in Pandorina morum have been studied in detail under controlled laboratory conditions. A number of strains from various areas of the United States, all essentially indistinguishable on morphological grounds, were analyzed for sexual compatibility. Forty-seven heterothallic clones were found to represent 15 separate pairs of mating types, or a minimum of 15 syngens (sensu Sonneborn, 1957). Two clones proved to be homothallic. Nine additional clones, which were not observed to mate with any strain, can be classified only after further collecting. The separate heterothallic pairs of mating types are sexually isolated by factors acting at the stage of gamete production; incompatible mating types produce no gametes when they are mixed together. The geographical distribution of the sets of mating types is very incompletely defined as yet, but they are not strictly endemic forms. Thirty heterothallic strains, representing each of the 15 sexually isolated sets of mating types of Pandorina morum, have been deposited with the Culture Collection of Algae maintained at Indiana University, Bloomington, Indiana, U.S.A.
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  • 54
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    Topics: Biology
    Notes: SYNOPSIS. When grown in CPLM medium or in a similar medium containing glucose instead of maltose as its sugar, Tritrichomonas foetus, Strain O, was much more sensitive to injury when frozen to -21d̀ C. in the presence. of 1 m glycerol during the initial and logarithmic phases of its population growth curve than at its peak and for some time thereafter. In 7 experiments in which the population peak occurred an average of 28.1 hours after inoculation, the average culture age at which the protozoa first survived freezing was 20.3 hours, at which time the population had reached 52.6% of its peak. The optimum culture age for survival after 1 day of freezing averaged 37.7 hours at which time the population averaged 75.6% of its peak. The optimum culture age for survival after 7 to 15 days of freezing averaged 32.3 hours, at which time the population averaged 82.7% of its peak. Better survival upon freezing was obtained in those experiments in which the population peak was reached relatively rapidly.
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  • 55
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Topics: Biology
    Notes: SYNOPSIS. Specimens of Blepharisma undulans were transferred from young clone cultures to a rotocompressor with 3 mm3 of culture medium. The organisms were slightly compressed and photographed at various intervals with dark field illumination. The sequence of macronuclear and cytoplasmic changes was compared with similarly followed Feulgen preparations.The cycle falls into several phases: (1) an interphase (12–24 hr.) in which the organism increases in size while cytoplasmic and macronuclear appearances remain unchanged. During this phase, the macronucleus consists of 3 to 5 nodes of various sizes connected by strands. (2) a pre-condensation phase (1 hr.) in which a new posterior peristome and cytopyge appear without visible macronuclear change. (3) a condensation phase (10–20 min.) in which the macronuclear nodes coalesce into a round mass without dissolution of the central nodes or strands. (4) a postcondensation phase (1 hr.) characterized by: (a) elongation of the condensed macronucleus into a rod-like shape followed by typical nodal formation; or (b) elongation of the condensed macronucleus into a form resembling the letter “J”, followed by nodal formation, and resulting in a double row of nodes in one daughter and a single row in the other. Separation occurs at this time, initiating the new interphase. The development of the j-form macronucleus. the lack of obliteration of the central nodes, and the characteristic interphase condition distinguish this strain of B. undulans from others described elsewhere.
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  • 56
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    Topics: Biology
    Notes: SYNOPSIS. Six species of astomatous Infusoria, 4 new, are described from the alimentary tract of Oligochaeta from Ochrida Lake. Two belong to Ochridanus, characterized by a cytoskeleton whose “V”-shaped basal piece bears on its branches two articulated hooks brought together by a skeletal blade. This genus found in Ochridanous Tubificidae represents the counterpart of Anthonyella in the Lumbriculidae of Lake Baïkal. The presence of Ochridanus in these worms concurs with the almost complete absence of representatives of Radiophrya of which we have found but one species. A species of Metaradiophrya, a genus unknown to date from the Lumbricidae, was noticed in Glossoscolecidae. The different species of Ochridanus, Anthonyella, Metaradiophrya, and Radiophrya compose a very homogeneous group of Radiophryinae. The study of the ciliary rows and the cytoskeleton of 2 species of Juxtaradiophrya, parasitic in the Lumbriculidae of Ochrida, shows that, in the morphology of these ciliates, as well as in the same forms from Lake Baïkal, many transition characteristics exist between the Radiophryinae and Hoplitophryinae or Mesnilellinae. These 3 sub-families, with their undeniable genetic kinship give coherence to the family Hoplitophryidae.
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  • 57
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    Topics: Biology
    Notes: SYNOPSIS. Histochemical techniques were used to demonstrate the intracellular distribution of some hydrases, hydrolases, oxidases, and dehydrogenases in Stylonychia pustulata. The hydrase, aconitase, was confined to the mitochondria. Zymohexase activity occurred in the cytoplasm and probably in the mitochondria. The hydrolases, acid and alkaline phosphatases, lipase, and urease, were localized in the mitochondria. Lactic and glutamic dehydrogenases were confined to the mitochondria. Peroxidase and glycerophosphate dehydrogenase were absent.
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    Topics: Biology
    Notes: SYNOPSIS. The oocysts, sporulation process, and endogenous stages of Eimeria raillieti (Léger, 1899) Galli-Valerio, 1930 from the slow-worm, Anguis fragilis, in England are described. The oocysts average 18 × 15 μ. Schizonts, microgametocytes and macrogametocytes were found in the ileum, and macro-gametocytes alone in the duodenum.
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  • 59
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
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    Topics: Biology
    Notes: SYNOPSIS. Zooxanthellae in pure culture, exposed to continuous light, release free O2 in amounts varying with time and cell number. Zooxanthellae exposed to alternate light and dark produce essentially as much O2 as in continuous light. Those in continuous dark do not yield free O2; rather, they draw from the medium's residual O2.Both the anemone Condylactis and the scyphozoan Cassiopeia are markedly phototactic. Kept in total darkness, both species show a dramatic numerical diminution in zooxanthellae. During 24 days of darkness, the mean total number of zooxanthellae in the individual Condylactis body was reduced from 26 million to ∼ 1 million. Specimens so bleached lost phototaxis.It is suggested that each species of zooxanthella host animal has its own specific light needs, which it caters to in various ways: (a) early selection of position, as with planulae or other freely motile larval forms; (b) gross body movement or posturing, as with anemones, medusae, and worms; (c) possession of light-filtering pigments, as with colored corals and molluscs; (d) possession of light-concentrating devices, as with tridacnids; (e) possession of highly contractile and differentially light-absorbing tissues, as with most coelenterates and some molluscs.Susceptibility of marine invertebrates to zooxanthellae infection may be related to the known paucity of nitrates and phosphates in tropical seas, a situation possibly inducing the free-swimming gymnodinioid forms to enter animal tissues where catabolic products are available to them. Zooxanthellae are reported from sessile marine invertebrates taken at depths of 100–116 fathoms.
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  • 60
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    Notes: SYNOPSIS. All of 99 adult English house-sparrows, examined in the St. Albans area of Hertfordshire, England, were found to be infected with the organism previously defined by Garnham (1950) as Atoxoplasma. Young birds were found to become infected while still in the nests and as early as 6 days after hatching; there was no evidence to suggest that the parasite was transmitted through the egg. Within a few weeks of leaving the nests, all of 150 fledgling sparrows examined were heavily infected and several trapped birds died from massive infections.All stages of schizogony were found in the lymphoid-macrophage cells of the spleen, bone marrow and liver of these birds; later, as the schizogonic cycle abated, gametocytes developed in similar cells of the liver, lungs and kidney. These gametocytes are of the Eimeria type: the zygote nucleus divides to produce an asporous and polyzoic oocyst containing a large number of sporozoites, and after the rupture of the oocyst these sporozoites invade the lymphocytes and monocytes of the peripheral blood.Transmission of the parasite in the sparrow is thought to take place after the ingestion of infected mites (Dermanyssus gallinae) by the young birds in the nests: unchanged sporozoites were found in smears of these mites that had been fed on infected sparrows. Transmission experiments were impossible due to the complete lack of clean sparrows.The taxonomic status of Atoxoplasma is discussed. The type of life cycle and the production of asporous, polyzoic oocysts indicate inclusion of this parasite in the Order Coccidiida, Family Eimeriidae, Sub-Family Cryptosporidiinae Hoare, 1933. After comparison of the two genera, the author concludes that Atoxoplasma must be regarded as a synonym for Lankesterella. Some previously described species of Atoxoplasma are, therefore, transferred to the genus Lankesterella.The name Lankesterella garnhami nov. sp., is proposed for the parasite in the English sparrow (Passer domesticus domesticus), and Lankesterella serini nov. sp., for that in the canary (Serinus canarius).
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    Notes: SYNOPSIS. Darkness and O2-lack promote formation of a pheophytin-like pigment from chlorophyll in Euglena gracilis in an acidic medium. Dinitrophenol (DNP) produces similar but more drastic pigment alterations in aerated and illuminated cells. The extent of pigment decay was dependent on DNP concentration and external pH. Since volume expansion and inhibition of the contractile vacuole were also noted, it is suggested that pheophytin formation is secondary to hydrogen ion influx from the external medium. Major structural alterations of the chloroplast accompanied the pigment changes.Pentachlorophenol, iodoacetamide, Na fluoride, and Na azide produced similar pigment changes. Malonic acid and fluoroacetate were ineffective under the conditions described. However, in the dark, cells treated with fluoroacetate formed pheophytin rapidly. These effects are discussed in relation to the maintenance of intracellular [H+].
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  • 62
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    Topics: Biology
    Notes: SYNOPSIS. The heterotrophic, phototrophic, and phagotrophic nutrition of the chrysomonad flagellates Ochromonas malhamensis and O. danica were compared. Unlike O. malhamensis, O. danica, which is much richer in chloroplast pigments, grew readily photoautotrophically in a substrate-free medium in 5% CO2. Utilization of bound biotin in bacterial (Thiobacillus) bodies served to demonstrate phagotrophy in both flagellates. This nutritional versatility suggests that this group of flagellates will be exceptionally valuable for studying the evolutionary steps connecting photoautotrophy, heterotrophy, and phagotrophy.
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  • 63
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    Topics: Biology
    Notes: SYNOPSIS. In a synthetic medium containing 57 compounds, including cholesterol, Trichomonas gallinae and T. gallinarum require 3 factors for growth and acid fermentation of maltose: (1) factor R, found in the protein contaminating some samples of ribonucleic acid, and in other isolated proteins such as conalbumin, γ-globulin, and bovine albumin fraction V; (2) factor T, found in Trypticase and in the same isolated proteins, but with activity at 4 times the dose required for factor-R activity, may be a large peptide containing proline; (3) factor S, found in serum, was replaceable by a saturated and an unsaturated fatty acid, each inactive alone. Only C14 through C18 saturated fatty acids were active over a range of 0.058 to 2.34 μm per tube in the presence of oleic acid, while C18 through C22 unsaturated fatty acids were active in the same range with palmitic acid as the supplement. The unsaturated fatty acids were toxic at the largest dose. All fatty acids were not equally active. Surface-active agents containing mixtures of fatty acids also replaced serum. A 4th factor, found in serum, stimulates the rate of growth as shown by cell counts at 3 days of incubation. T. gallinarum, T. foetus, and a trichomonad from a pig's nose responded to the same supplements when grown on another synthetic medium.
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    Notes: SYNOPSIS. Differences in temperature-tolerance, generation time, nutritional requirements, osmoresistance, pigment production, and sensitivity to high hydrogen or hydroxyl ion concentration have been observed among varieties, and among mating types within varieties of Tetrahymena pyriformis. The usefulness of these differences to taxonomists and geneticists is discussed.The nutrition of a temperature-tolerant strain, mating type II, variety 1, was given special attention and a chemicallydefined medium devised to support rapid growth at 35d̀ C. At 40d̀, growth in this medium failed, but was good in a crude medium. Temperature factors are suggested. Permeability of this ciliate, as inferred by utilization of nucleotides, was high.
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    Notes: SYNOPSIS. Eight strains of Tetrahymena pyriformis were examined in multiple daily isolation series over ∼ 800 generations. Dead and defective lineages appeared in all clones. In 7, the defective sub-lines appeared at a constant characteristic rate; the 8th showed an increasing rate of production of two defects. A breeding analysis of certain persistent morphological and growth rate variants suggests that the variations derive from macronuclear alterations. The relationship between these cellular changes and “senility” in metazoa and other protozoa is discussed.
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    Notes: SYNOPSIS. An acetone-insoluble yeast fraction required for axenic growth of P. aurelia, stock 51, variety 4, sensitive, after fractionation contained at least 3 essential components: (1) one soluble in perchloric acid and completely replaceable by a mixture of ribosides or ribotides; (2) one inactivated after digestion with trypsin, chymotrypsin or papain. Proteose-Peptone restored activity to this preparation, which suggests a peptide requirement; and (3) one not yet characterized.As for the purine and pyrimidines, these combinations, in decreasing order of activity, supported growth: guanosine + cytidine, guanosine + uridine, guanylic acid + cytidylic acid, and guanylic acid + uridylic acid. Each combination was maximally effective when the molar purine: pyrimidine ratio was ∼ 0.4. On a molar basis, the minimal riboside combinations were ∼ 1.3 × more active than the ribotides.Sparing of the purine and pyrimidine requirement was also investigated. In the presence of limiting amounts of guanylic acid, the following compounds, in decreasing order of activity, had sparing activity: deoxyguanosine, inosine, xanthosine, adenylic acid, and guanine. Adenine, adenosine, and deoxyadenosine were inhibitory under the test conditions. The requirement for cytidylic acid was spared by deoxycytidine, uridine, uridylic acid, deoxyuridine, thymidine, thymine, and uracil, in descending order.
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    Notes: SYNOPSIS. In reviewing 25 years of work on Tetrahymena, the author describes early difficulties experienced by himself and others in developing a chemically-defined medium and in defining the taxonomy of T. pyriformis. With identification of its essential requirements, a variety of nutritional studies revealed the close resemblance between the metabolic pathways of this ciliate and those of the chick and rat. This suggested studies on the effects of gamma radiation and the effect of antibiotics.Attention then turned to the puzzle of the absence of conjugation in all strains of T. pyriformis then maintained in laboratories. The observation that these strains were all amicronucleate led to the discovery of mating types (with D. F. Gruchy). This brought up the problem of what constitutes a species and how it might be solved in T. pyriformis where clearly defined groups are set off from other similar groups (varieties) by a breeding barrier.Another problem is whether a life cycle exists in this ciliate and if so, the role amicronucleate strains play in this cycle.The origin and obvious evolutionary success of these “genetically dead” strains are other problems that are considered.The search for nutritional markers for genetic experiments inspired large-scale collections, including some from tropical habitats. Strains were found which differed in serine and pyridoxine requirements. Genetic analysis was hindered by the high lethality following conjugation, unsatisfactory mating behavior in some clones, and the complete absence of autogamy, the latter making it difficult to obtain homozygous clones. The use of x-radiation yielded haploid individuals; when these were mated with diploid clones the resulting haploid progeny proved that the genes controlling mating type and pyridoxine synthesis resided in the micronucleus.Genetic analysis of the serine and pyridoxine mutants supports the idea that T. pyriformis is more of an outbreeder than an inbreeder. Left for the future is an extension of our knowledge of the breeding system of T. pyriformis and ultimately to examine critically the factors responsible for the success of this ubiquitous ciliate.
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    Notes: SYNOPSIS. During encystment of Colpoda cucullus (O. F. Müller) the respiratory rate decreases from about 11.3 × 10-5μl. O2/hr. (mean value for active form) to about 1.3 × 10-5μl./hr. (mean for unstable cyst); the process takes about 24 hrs. At the same time the activity of the contractile vacuole is stopped, but there is no correlation in time between the two processes: when respiration is inhibited by 1/2–2/3 the vacuolar activity is hardly changed. The respiration of unstable cysts remains approximately constant at least for 4 weeks. Experiments with methylene blue suggest that inhibition of respiration at encystment may be due to inhibition of terminal oxidase.
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    Notes: SYNOPSIS. Two isolates (“A” and “B”) of Trypanosoma lewisi from the same rat stock source were serially transferred in calorically-restricted mice supplemented daily with normal rat serum. The “A” strain was transferred consecutively through 300 mice over a period of more than 3 years and was voluntarily discontinued. The “B” strain died out spontaneously after 43 consecutive passages in mice. The developmental histories of these 2 isolates were analyzed and compared with respect to duration of the parasitemic period, interval to the next subsequent passage in mice, day of death of each host animal, proportion of host animals that died, intensity of parasitemia in mouse tail blood, interval required for development of the observed maximal parasitemia, and duration of maximal parasitemia.“A” appeared to have become progressively adapted to the mouse as judged by a decrease in parasitemic period with successive transfer associated with a progressive increase in trypanosome population, and declines in the interval required for development of the observed maximal parasitemia and in the duration of this maximal response. There did not appear to be any correlation of the percentage of animals that died with any other factor. The “B” strain did not appear to have adapted itself to mice as judged by the foregoing criteria.
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    Notes: SYNOPSIS. The Indian race of Blepharisma undulans described in this paper measures 150 μ in length. The macronucleus consists of 5–7 nodes, all of equal size. During binary fission, condensation of macronucleus is followed by its elongation and a thinning of the middle region which breaks with the division of the animal. It later attains the typical vegetative form.During conjugation 7 or 8 micronuclei pass through the first pregamic division, 5 to 7 through the second pregamic division and one product of the second division takes part in the third division. The rest degenerate. At the same time, the macronucleus also starts degenerating. After the synkaryon has divided twice, the conjugating pairs separate. Of the 4 products, 3 become macronuclear anlagen and one, micronuclear anlage.The micronuclei divide asynchronously both during binary fission and during conjugation. There is apparently considerable diversity in the structure and behaviour of the macronucleus and micronuclei in the different races of Blepharisma undulans.
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    Notes: SYNOPSIS. In cattle fed a high-starch diet, species of Entodinium and Diplodinium ingested associated ruminal bacteria. Stained preparations of diluted rumen contents showed Entodinium caudatum, E. minimum, E. dubardi, (syn. E. simplex), E. longinucleatum, E. bursa, E. nanellum, E. exiguum, and E. vorax contained gram-positive diplococci. Starch grains with adherent gram-positive diplococci were observed within Entodinium spp. Diplodinium ecaudatum forma ecaudatum, D. ecaudatum forma caudatum, D. neglectum and an unidentified species of Diplodinium also ingested ruminal diplococci. Bacteria were isolated from mixed species of Entodinium by washing and culturing the protozoa in a starch feed-extract agar medium. The strains isolated from the ciliates were gram-positive diplococci, 0.8 times 1–1.5 μm, which attached themselves to starch granules and were able to digest the starch. Conclusive evidence of bacterial ingestion by the oligotrichs was obtained by providing the bacterial cultures to Entodinium species (E. dubardi and E. minimum) which had been starved 24 hr. Gram-stained preparations showed the ciliates readily ingested the bacteria. The amylolytic cocci utilized by Entodinium spp. were identified as Streptococcus bovis.
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    Notes: SYNOPSIS. Lankesterella corvi n. sp. (Coccidia, Eimeriidae, Cryptosporidiinae) is described from the rook, Corvus f. frugilegus L. in England. It was found in 36 of 196 fledged rooks less than 1-year old, but not in 25 nestlings or 38 adults. It was not found in 71 jackdaws (C. monedula spermologus) or in 110 other birds of 16 species.Mature sporozoites were found in the erythrocytes and occasionally in other blood cells. They were 6.2 times 2.5 μ, with a central, band-like nucleus, and cytoplasm which failed to stain with Giemsa's stain. Gametogonic and sporogonic stages, found in the bone-marrow of one bird, resembled corresponding stages of Eimeria.A fledgling rook was infected experimentally by inoculation of a blood and tissue suspension from an infected bird. Sporozoites appeared in its blood 4 days after inoculation. They appeared to increase slightly in size and their cytoplasm lost its initial affinity for Giemsa's stain during the next few days. Engorged mites (Ornithonyssus sylviarum) from the experimentally infected rock contained unchanged sporozoites but no developmental stages of the parasite. A canary could not be infected by intraperitoneal inoculation and feeding of such mites.
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    Notes: SYNOPSIS. A dichotomous, analytical key is offered for use in recognition and differentiation of the 26 orders and suborders belonging to the two subclasses of the single class Ciliata of the subphylum CILIOPHORA. The basic terminology employed in these brief characterizations, usable in systematic studies of ciliates in general, is defined first, and a plea is made for a more uniform vocabulary, especially in reference to structures which are without doubt homologous throughout the several higher ciliate taxa. Particular emphasis is placed on the all-important features in the oral area; many of these are figured as well as being described in words.Both the key and the definitions are essentially the first to be offered since Kahl's monographic work on the ciliates published in 1930–1935. They are demanded by the great accumulation of new pertinent data in the protozoclogical literature of the past 25 years.
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    Notes: SYNOPSIS. The flagellate, Peranema trichophorum, has been studied in the electron microscope by thin-sectioning techniques. The flagella have the fibrillar pattern typical of cilia and flagella, but accessory structures including tapered, intraflagellar rods, striated, layered material on the outside of the membrane, and mastigonemes are present. In the near basal region of the flagellum, there is a swelling of the shaft which is correlated with the absence of the two central flagellar fibrils. The basal portion of the intraflagellar material is structurally and locationally similar to the basal parts of the flagellar fibril bundle; this similarity suggests that the two structures originated from similar precursors and that two kinetosomes comprise the light microscopist's blepharoplast in this organism.The ridged pellicle is composed of 3 membranes, only two of which follow the contour of the ridges. Several filaments 21 mμ in diameter are localized under the low point of each ridge, and a single, larger fibril which has a periodic structure is often located beneath the high point of each ridge.The cytostome and structures associated with it are described and discussed in relation to food taking. The pharyngeal rods are cross-connected and each is composed of numerous tubular elements surrounded by a denser, homogeneous layer. A system of membranes is attached to the rods and extends anteriorly.The nucleus contains two large nucleoli, numerous rod-shaped, membrane-limited bodies which appear similar in structure to bacteria, and a smaller granular component.Other organelles are briefly described including mitochondria, Golgi bodies, vacuoles, and endoplasmic reticulum.
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    Notes: SYNOPSIS. Materials within the endoplasm of both the protomerite and deutomerite may be displaced and stratified by ultracentrifugation. Animals are not killed by this treatment, and in time a redistribution of stratified materials may occur. The electron microscope reveals numerous ultramicroscopic folds in the surface envelope which is composed of 3 membranes; the outer and middle cover the surface of the folds while the inner one continues as a smooth membrane over the ectoplasm. The contact surfaces of animals in syzygy do not show the small folds to be interlocked; instead, they are in fold-to-fold contact. Numerous relatively dense bodies which appear to be filamentous are sometimes observed immediately underneath or within the middle or inner membrane. Within the ectoplasm is an ultramicroscopic net-like fibrillar structure much denser than the surrounding cytoplasm. This system of fibrils is composed of anastomosing elements varying from ∼ 50 to 200 Å in diameter. Certain of the larger fibrils are directly attached to the surface envelope at positions between the folds. A second filamentous structure within the ectoplasm appears to be tubular. Elements of this system also appear to join and penetrate the surface envelope by means of pores.A large amount of gelatinous secretion forms at the surface of the sporont; as it glides forward a trail of mucous is left behind. The actual mechanism involved in the gliding movement was unobserved, but evidence is lacking to support the view that the gliding movement is engendered by posteriorly directed “jets” of mucus.
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    Notes: SYNOPSIS. Vorticellas were subjected to achromycin, polymyxin, and mixtures of penicillin-streptomycin to remove bacterial contaminants. Although achromycin and polymyxin were most effective in controlling bacteria isolated from vorticella cultures, they proved too toxic for practical use. However, certain dilutions of penicillin-streptomycin were tolerated by vorticellas and, therefore, were incorporated into the axenizing procedure. Yeasts did not yield to the antibiotics and had to be removed by washing and dilution. Sterile vorticellas were finally obtained by transfer of groups of individuals through 6 washes. One of these, the 4th, lasted 8 hours and contained diluted penicillin-streptomycin.
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    Notes: SYNOPSIS. The interphase nucleus of Lesquereusia spiralis, a testate rhizopod, 20–25 μ in diameter, contains 40–50 endosomes and a diffuse granular reticulum. Onset of nuclear division is marked by a cessation of pseudopod activity. Prophase changes include increase in size of the nucleus, disappearance of the endosomes except the peripheral ones, formation of 175–200 chromosomes from the reticulum, and the appearance of spindle fibers. By the end of prophase a well formed equatorial plate is present. The metaphase nucleus is slightly smaller and elongated; the chromosomes remain distinct. In anaphase the nucleus continues to elongate along the polar axis; the chromosomes apparently split lengthwise and polar caps appear. The nucleus elongates further so that by telophase it has become hour-glass shaped. The spindle fibers are now twisted. Separation of the nuclei takes place in the neck region. The nuclear membrane is unbroken during the process and peripheral endosomes are present at all stages. Total time for mitosis averages 45 minutes.
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    Notes: SYNOPSIS. Three gregarines are described from the digestive tracts of marine crustacea from Bombay, India. These are Carcinoecetes etisi n.sp. from Etisus laevimanus, C. matutae n.sp. from Matuta lunaris, and Caridohabitans setnai n.gen., n.sp. from Peneus semisulcatus. Various life history stages are reported.
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    Notes: SYNOPSIS. In various ciliates the contractile vacuole is a permanent organelle, delimited by a differentiated cortex.The cortex is made up of a dense reticulum of anastomosing tubules limited by a smooth membrane, and vesicles. This “spongiome” can be considered as a localized and specialized condensation of the endoplasmic reticulum.
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    Notes: SYNOPSIS. Two species of flagellate parasites, Herpetomonas muscarum (Leidy 1856) Kent 1881 and Crithidia luciliae (Strickland 1911) have been isolated in pure culture from the fly, Phaenicia sericata. Laboratory-reared Musca domestica were infected with each of the species. These two species have often been confused, the latter being regarded as “cysts” of the former. H. muscarum is long and slender and occurs actively swimming in the midgut of the host. C. luciliae is short and truncate and occurs mainly in the hindgut where it is often attached to the gut wall. C. luciliae grows readily and abundantly in culture and outgrows H. muscarum in mixed cultures. Attempts to infect Aedes aegypti and Culex pipiens with C. luciliae failed while control feedings of these mosquitoes with Crithidia fasciculata produced infections.
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    Notes: SYNOPSIS. Trimastigamoeba philippinensis Whitmore 1911 from Florida was cultured in the laboratory at 22 to 25° C. on a modified Bunting's agar medium overlaid or not with Neff's ameba-saline. Studies of its general morphology, transition from ameboid to flagellate phase and vice versa, encystment, and excystment were made. In general, Whitmore's observations are confirmed, except for his conclusions concerning the number of flagella and whether or not there is a rhizoplast. The flagellate phase has two mastigonts, each composed of a pair of flagella attached to a basal granule (blepharoplast). Intermediate stages in the development of the mastigonts may have caused Whitmore to decide that a tri-flagellar phase was the usual condition. The two mastigonts are not at any time attached to one another, nor to the nucleus, nor is there any evidence of a rhizoplast or rhizostyle. In the flagellate phase the bases of the mastigonts are closely surrounded by an anterior, gullet-like invagination, posterior to which the blepharoplasts rest adjacent to the nucleus. The four flagella extend 20 to 25 μ beyond the anterior limit of the pocket. Detailed descriptions of the morphologies of the ameboid and flagellate phases are given to supplement the morphology described by Whitmore. Possible affinities to other amebo-flagellates are discussed. It is concluded that the organism is generically and specifically distinct; and while its name is erroneously descriptive of its flagellate phase, it is taxonomically valid.
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    Notes: SYNOPSIS. The organism used in the experiments fits Pierson's satisfactory description for Euplotes eurystomus. The mating behavior of 90 stocks of E. eurystomus collected from west Japan was studied. Mating occurs only after a decline in nutritive conditions. When the stocks were mixed together, two at a time, in all possible combinations, mating took place in all the mixtures. Mating occurs in the evening or the morning after mixing. An agglutinative reaction does not precede mating; but before pair formation, characteristic pre-pairing behavior is observed. Selfing is found in all the stocks, usually after the log-phase of the growth curve. Culture fluids from various cultures have no detectable capacity to induce selfing, but some of them can suppress selfing. The latter occurs only in specific combinations. Controls mixed with distilled water instead of culture fluid always contain selfers. From the results of such experiments, it is possible to classify the stocks into 9 types, so that stocks of the same type have the same character with respect to suppression of selfing. The culture fluid from type II suppresses selfing only in animals of type I, type IV acts only on type III, VI on V, VIII on VII, and VII on both V and VI. The reciprocal actions also occur, i.e., fluid from I suppresses selfing of type II, etc. The origin of the two mating members of a conjugating pair was traced by making mixtures of normal animals of one type with morphologically abnormal animals of another type. The latter have a distinct swelling at the left margin of the body. Such mixtures (I × II, V × VI and VII × VIII) yield conjugating pairs of normal mated with abnormal animals, i.e. cross-conjugating pairs, in 86–94% of the animals. Mixtures of type VI with VII yield a smaller percentage (48%) of cross-conjugating pairs. Mixtures of two cultures belonging to the same type, (II × II, VI × VI and VIII × VIII), in which selfing is not suppressed, yield 42–50% conjugating pairs of normal with normal, (selfing of the normal culture), and 32–45% conjugating pairs of abnormal with abnormal, (selfing in the abnormal culture). Mixtures of two cultures belonging to diverse types in which selfing is not suppressed (I × V, I × VIII, II × III, II × VII, II × IX, III × V, III × VI, III × VIII, IV × VI and VI × IX), yield 36–48% conjugating pairs (selfing) of normal with normal, and 26–50% conjugating pairs (selfing) of abnormal with abnormal. Interbreeding between two types thus normally occurs only when culture fluid of each type inhibits selfing by animals of the other type. These two types, which interbreed freely, may be considered as complementary mating types. The mating types of E. eurystomus thus fall into 5 varieties so that each one (except the fifth) has two complementary mating types. The mating types are numbered I and II in variety 1, III and IV in variety 2, V and VI in variety 3, VII and VIII in variety 4, and only IX in variety 5. Intervarietal mating does not occur in many combinations, but exceptionally it occurs between types V and VII, and between VI and VII. These hybrids become senile and finally die.
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    Notes: SYNOPSIS. Two methods for purifying balantidia are described. The first one may be applied to cultures which are not thriving when it is desirable to keep the purified ciliates without loss in number. Another method may be used for bulk material such as intestinal contents containing these ciliates.
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    Notes: SYNOPSIS. A piroplasm occurring in the erythrocytes of 38 of 42 echidnas (Tachyglossus aculeatus) has been described and named Babesia tachyglossi.
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    Topics: Biology
    Notes: SYNOPSIS. Identical cultural forms of Trypanosoma granulosae occur in NNN agar, Diamonds SNB-9 agar and Proteosepeptone blood agar. The inclusion of penicillin G sulfate and streptomycin had no effect upon the cultures. The first cultural forms to appear (24 hours) were long, slender crithidia which divided to produce short slender crithidia. The latter were the only forms encountered until the 18th day when rosettes, composed of 3–10 short, slender crithidia were found. Following the production of metacyclic trypanosomes (24th day) the culture rapidly died. Transfer of metacyclic trypanosomes and rosettes did not extend the length of culture life. T. diemyctyli is also unaffected by antibiotics and shows similar growth in all media used. Division in this species begins 50–96 hours after inoculation with the production, from the blood stream form, of two unequal, plump crithidia. These divide twice to form slender crithidia; the latter rapidly divide, but do not separate, and yield rosettes with a maximum number of 60 individuals. As the slender crithidia leave the rosette each either remains in the same form or transforms to a plump, pear shaped individual. Secondary rosettes are then formed from the latter. Metacyclic trypanosomes appear, in small numbers, after the 14th day.
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  • 87
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. In a survey of coccidia of rodents from Harbel, Libera, the following species of Eimeria were found and described: E. musculoidei n. sp. from Mus (Leggada) musculoides; E. separata Becker & Hall, 1931 from Rattus (Dephomys) defua (new host record); E. praomysis n. sp. from Rattus (Praomys) tullbergi rostratus; E. dasymysis n. sp. from Dasymys incomptus rufulus; E. lemniscomysis n. sp. from Lemniscomys striatus striatus; and E. lophuromysis n. sp., E. sikapusii n. sp., E. liberiensis n. sp., E. harbelensis n. sp., E. africana n. sp., and E. kruidenieri n. sp. from Lophuromys sikapusi sikapusi.
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  • 88
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. The morphology of 4 genera of the family Trypanosomatidae has been studied with particular reference to the contractile vacuole, reservoir, flagellum, undulating membrane, kinetoplast, and nucleus. Both the contractile vacuole and reservoir have been found in all species examined. Four morphological types of culture forms are described with special reference to these structures: (1), the Crithidia fasciculata type which is short and membraneless with a rounded posterior end, truncate anterior end and a well developed reservoir; (2) the Herpetomonas muscarum type with no undulating membrane, a truncate posterior end, a rounded anterior end and a reservoir which varies in length from about 1/6 of the length of the body to the full length of the body; (3) the Leishmania type with no undulating membrane, a pointed posterior end, an asymmetrical anterior end and a short reservoir which remains constant in size; and (4), the short-membraned type exemplified by Trypanosoma cruzi, with a pointed posterior end, a short reservoir near the middle of the body and the flagellum attached to the body along a portion of its length. This last form is derived from the blood stream morphology as exemplified by Trypanosoma lewisi in the rat by a shifting of the kinetoplast, flagellum, reservoir and contractile vacuole along the surface of the body from a position posterior to a position anterior to the nucleus.
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  • 89
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Exposure to non-lethal doses of ultraviolet completely inactivates chloroplast development and chlorophyll synthesis in Euglena gracilis var. bacillaris and in the Z strain. Treatment with visible light immediately following UV reverses the inactivation completely. The presence of chloroplasts is not necessary for this inactivation since similar results are obtained with light-grown cells (containing chloroplasts) and dark-grown cells (lacking chloroplasts).
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  • 90
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Strains of Trypanosoma rhodesiense resistant to atoxyl and to antrypol respectively were allowed to multiply in the blood of mice and were also maintained for some hours in the gut of tsetse flies. They failed to acquire cross-resistance as shown by tests with the respective drugs given singly and in combination to infected mice.
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  • 91
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Paramecium multimicronucleatum was grown in a buffered desiccated lettuce medium maintained at pH 7.5, with Aerobacter aerogenes the main bacterial source. The maximum expansion in length and width was at pH 6.0; the minimum expansion in length and width at pH 8.5. The paramecia were usually stouter at pH levels 〈 7.0 except at pH 5.5 and generally more slender 〉 pH 7.0.The pH of the medium affected the size of food vacuoles as indicated by the fact that the maximum food vacuolar diameter was at pH 6.0, the minimum at 7.0.The fastest and greatest expansion of food vacuole diam. was at a relative viscosity of 8; the minimum food vacuolar diam. was in controls (without gum arabic) having a viscosity of 1.3.
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  • 92
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Trypanosoma granulosae n. sp. was found in the salamander, Taricha granulosa twittyi, from Dutch Bill Creek, Sonoma County, California. This polymorphic trypanosome has an anterior nucleus containing a definite endosome. The kinetoplast is rod-shaped and never contained within a vacuole. Myonemes are occasionally seen in slender individuals.
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  • 93
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Balantidium coli was cultured for 4 months in Dobell-Laidlaw's medium. About 10 specimens of monsters were found in the preparations (Chatton-Lwoff silver impregnation technique). One individual showed a tendency to polystomy. One doublet of Balantidium caviae (?) in preparations treated by the same technique was found in a population from a guinea pig.The monsters of Balantidium coli are either single distomic individuals or doublets (homopolar or heteropolar).The infraciliature of the monsters shows different degrees of deviation from the normal pattern. No reorganization field during the formation of additional cytostomes was observed, which agrees with the data on normal stomatogenesis. This process is very similar in both normal specimens and monsters and is characterized by the arrangement of radiating kineties surrounding the anlage of the cytostome and, evidently, by invagination of this area which later forms the peristome. The fate of single monsters and that of homopelar doublets is unknown. The heteropolar monsters are considered non-viable because the arrangement of the kineties in both presumptive daughters contradicts the rule of desmodexy (Chatton-Lwoff).The occurrence of the monsters in cultures may possibly be explained by the action of acriflavine which is mutagenic for Escherichia coli, or by gentian-violet which inhibits fission of sea urchin eggs.This paper apparently constitutes the first presentation of anomalies of the infraciliature in parasitic ciliates.In addition the exact arrangement of the kineties and kinetosomes at the posterior pole of Balantidium coli is described.
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  • 94
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. A nonpathogenic strain of Histomonas was used in an attempt to immunize young turkeys against blackhead. Rectal inoculation of several thousand nonpathogenic histomonads on 2 or 3 consecutive days afforded considerable protection against modest rectal challenges with pathogenic histomonads 3 to 6 weeks later, but was much less effective against pathogenic histomonads introduced by feeding eggs of Heterakis gallinae. It is believed that an immune barrier limited to the surface of the cecal mucosa was established, and that the larvae of the cecal worms often penetrated this barrier before liberating their histomonads, thus permitting blackhead to develop. Immunization by the introduction of nonpathogenic histomonads with Heterakis eggs was not satisfactory. Apparently, the nonpathogenic organisms introduced in this way were too few to assure formation of an intact barrier.
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  • 95
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Podophrya collini was fed homozygous killer Paramecium aurelia (containing kappa particles DNA). The rate of giant formation in the suctorian population was then determined; controls were fed homozygous sensitive P. aurelia. No difference in the rate of giant formation was observed; the DNA contribution by the kappa particles was not enough to induce a higher rate of giant formation. Cultures of P. collini containing only animals of known uniform age were then fed controlled numbers of Tetrahymena pyriformis or sensitive P. aurelia after these ciliates had been pretreated with guanylic acid, 8-azaguanine, commercial DNA or DNA isolated from Tetrahymena. Giant formation was increased after guanylic acid pretreatment, reduced after the 8-azaguanine pretreatment, and unaffected after DNA pretreatment over a 5-day test period. The changes in rate of giant formation are clearly caused by pretreatment agents. These agents reach the suctorian's metabolism via the food ciliates' food vacuoles before they are altered in the food vacuole.
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  • 96
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Polytomella caeca utilizes as sole carbon sources in chemically defined media: acetate, propionate, butyrate, valerate, pyruvate, succinate, ethyl, butyl, amyl, and hexyl alcohols. Glyceraldehyde and α-ketoglutarate sustain very small populations. Caproate, caprylate, fumarate, malate, propyl, heptyl, and octyl alcohols and the iso-compounds iso-butyrate, iso-butyl and iso-hexyl alcohols are inadequate.Acetate is not assimilated 〈pH 5.0, propionate and butyrate 〈pH 6.0, and valerate 〈pH 7.0. Optimum for utilization of succinate is pH 3.0, for pyruvate pH 4.0, utilized also at pH 2.0 Fatty acids are utilized dissociated; succinate and pyruvate are utilized undissociated. Alcohols are assimilated throughout pH 4.0–7.4, except hexanol at pH 7.4. Alcohol availability is proportional to molecular length-1.pH after growth of fatty acid media is 8.4 ± 0.4; stable in pH 2.0 pyruvate and pH 3.0 succinate media; 3.5 ± 0.3 in alcohol media with initial pH 〈6.0. Longer alcohols cause less pH decrease during growth.Acetate concentrations 〈0.2% do not support maximum populations; concentrations of 0.2–1.0% do. pH after growth increases in these media to pH 8.5 with maximum populations.Malate, fumarate, α-ketoglutarate, and lactate seem not to penetrate the cell, but are metabolized by homogenates. Methylene blue reduction by homogenates indicates the presence of lactic, malic, succinic and α-ketoglutaric dehydrogenases, fumarase and glutamic transaminase. Extracts contain Embden-Meyerhof phosphate esters, ATP, and ADP.
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  • 97
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. An immunity to reinfection with E. bovis was demonstrated in 3 experiments involving 60 calves. This immunity develops rapidly, as indicated by resistance to a challenge given 14 days after the immunizing inoculation. In 3 groups of 3 to 6 young calves each, immunity was still present to a moderate degree 2 to 3 months after inoculation; in one group of 5 animals about a year old there was apparently a high degree of immunity about 7 months after the last inoculation. In one experiment an immunizing inoculum of 10,000 oöcysts did not produce as much immunity as 50,000 oöcysts. In 2 experiments there appeared to be little difference in the immunity produced by a single inoculation of 50,000 as compared with 100,000 oöcysts, but inoculation with 100,000 oöcysts, resulted in substantially longer and more severe illness than 50,000 oöcysts. There appeared to be no appreciable difference in clinical symptoms or development of immunity between calves given a single immunizing inoculum and those given the same number of oöcysts in 5 equal inocula on successive days. Treatment with sulfamethazine and sulfamerazine (Merameth) 13 to 15 days after inoculation alleviated the clinical symptoms of coccidiosis without interfering appreciably with the development of immunity. In one experiment with 7 calves, no beneficial effect was noted from 1 or 2 transfusions of 500 ml. of plasma and leucocytes from immune calves into 4 calves 1 and 12 days or 11 days after a challenge inoculation.
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  • 98
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Experiments were carried out to determine if the course of infection with Plasmodium cathemerium was changed when the temperature of incubation of the duck embryo host was lowered. At 30° C. the infection developed more slowly and never reached the peak seen in infected embryos incubated at 37° C. If infected embryos at 30° were returned to 37° C. the resultant parasitemia developed similarly to that usually seen in this host at the latter temperature. Studies of the periodic behavior of the parasite at 30° C. and 38° C. revealed no differences in the time of segmentation. Merozoite counts were unchanged. The reduced parasitemia in embryos at 30° C. may result from reduced ability of the parasite to penetrate new host cells.
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  • 99
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Pelomyxa illinoisensis exhibits several phenomena of an interesting and uncommon nature, such as the presence of polar granules and the appearance of chromosomes through most of the resting and dividing stages of the nucleus. For these reasons and because of the importance of the nucleus as a stable characteristic in the taxonomy of amoebae, this study of the nucleus and nuclear division was undertaken.Culture methods were the same as those used for P. carolinensis. Best fixatives for nuclei were Carnoy, Flemming, 10% formalin, Duboscq-Brazil, Schaudinn and 2% osmium tetroxide. The body shape of P. illinoisensis in nuclear division is correlated with the stage of nuclear division and resembles the same stages in Amoeba proteus and P. carolinensis, with the exception of a ragged appearance of the cytoplasm of organisms containing prophase nuclei and the halo-like appearance of the pseudopods in those containing metaphase nuclei. The condensation of resting nuclei when subjected to acidified methyl green, reported by Kudo (18), occurred with all fixatives used with the exception of 10% formalin and 2% osmium tetroxide. The metaphase nuclei have a disk of polar granules on either side of the equatorial plate with fibers running from them to the chromosomes. The nature of these granules is unknown. Similarities and differences between P. illinoisensis and P. carolinensis are discussed.
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  • 100
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    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Inhibitors, acid production, and substrate utilization by 4 strains of Tritrichmonas foetus (BP-3, BP-4, A-1, and A-2) were studied manometrically. All used glucose, galactose, mannose, fructose, sucrose, maltose, trehalose, glycogen, starch, lactate, and pyruvate. Strain A-1, with the highest aerobic and anaerobic endogenous rates, used these substrates less than did the others. Strain BP-3 did not use lactose; strains BP-4 and A-2 did not use raffinose aerobically and only slightly anaerobically; strain A-1 used both nearly as well as maltose and sucrose. All were strongly inhibited by iodoacetate and, if tested in the presence of glucose, aerobically or anaerobically, by fluoride, arsenite, hydroxylamine, and 8-hydroxyquinoline. Aerobically, 2,4-dinitrophenol produced stimulation which was greater in the presence of glucose; anaerobically, it produced inhibition which was, in some cases, comparable to the effects produced by the other inhibitors. Fluoride, arsenite, azide, and hydroxylamine, although producing insignificant inhibitory effects on endogenous O2 consumption, reduced and, in some cases, abolished motility of all strains. All 4 strains produced acid under anaerobic and aerobic conditions; strain A-1 produced more than the others. Lactic acid accounted for 30–51% of the acid produced in all strains.Strain A-1 more closely resembled the nasal trichomonad of swine (strain PN-610) than did strain BP-1. (Doran(3)). The writer believes that the swine nasal strain is a highly adapted strain of T. foetus.
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