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81.
The ability to change the reproduction mode and produce diapausing eggs, which is prevalent in many zooplankton species, significantly
impacts on the evolution and ecology of aquatic communities. The production of diapausing eggs is controlled by multiple effects
of biotic and abiotic factors, including infochemicals. We have investigated the effects of chemicals exuded by conspecifics
and ecologically close competing congers, Moina brachiata and M. macrocopa, which coexist in the same water body, and by larger Cladocera species (Daphnia magna) on the change of reproduction mode, specific growth rate and fecundity of M. brachiata and M. macrocopa females. The production of gametogenetic eggs in both species was detected only in waters from crowded cultures of conspecifics.
The water from crowded cultures of conspecifics reduced the specific growth rate of the juvenile females of both species that
later switched to gametogenesis. While it either did not affect (in M. macrocopa) or even increase (in M. brachiata) the specific growth rate of the juvenile females that later reproduced by parthenogenesis. Females of M. macrocopa released significantly fewer neonates in the water from crowded cultures of conspecifics than in all other treatments, while
the fecundity of M. brachiata females was the same in all treatments. To understand the phenomenon of diapause induction under the effect of chemical cues
in zooplankton, a link between laboratory tests and ecological research should be established, and the chemical composition
of the signals should be determined. 相似文献
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Nariman Battulin Veniamin S Fishman Alexander M Mazur Mikhail Pomaznoy Anna A Khabarova Dmitry A Afonnikov Egor B Prokhortchouk Oleg L Serov 《Genome biology》2015,16(1)
BackgroundThe three-dimensional organization of the genome is tightly connected to its biological function. The Hi-C approach was recently introduced as a method that can be used to identify higher-order chromatin interactions genome-wide. The aim of this study was to determine genome-wide chromatin interaction frequencies using the Hi-C approach in mouse sperm cells and embryonic fibroblasts.ResultsThe obtained data demonstrate that the three-dimensional genome organizations of sperm and fibroblast cells show a high degree of similarity both with each other and with the previously described mouse embryonic stem cells. Both A- and B-compartments and topologically associated domains are present in spermatozoa and fibroblasts. Nevertheless, sperm cells and fibroblasts exhibit statistically significant differences between each other in the contact probabilities of defined loci. Tight packaging of the sperm genome results in an enrichment of long-range contacts compared with the fibroblasts. However, only 30% of the differences in the number of contacts are based on differences in the densities of their genome packages; the main source of the differences is the gain or loss of contacts that are specific for defined genome regions. We find that the dependence of the contact probability on genomic distance for sperm is close to the dependence predicted for the fractal globular folding of chromatin.ConclusionsOverall, we can conclude that the three-dimensional structure of the genome is passed through generations without being dramatically changed in sperm cells.
Electronic supplementary material
The online version of this article (doi:10.1186/s13059-015-0642-0) contains supplementary material, which is available to authorized users. 相似文献84.
Nikki R. Paul Jennifer L. Allen Anna Chapman Maria Morlan-Mairal Egor Zindy Guillaume Jacquemet Laura Fernandez del Ama Nermina Ferizovic David M. Green Jonathan D. Howe Elisabeth Ehler Adam Hurlstone Patrick T. Caswell 《The Journal of cell biology》2015,210(6):1013-1031
Invasive migration in 3D extracellular matrix (ECM) is crucial to cancer metastasis, yet little is known of the molecular mechanisms that drive reorganization of the cytoskeleton as cancer cells disseminate in vivo. 2D Rac-driven lamellipodial migration is well understood, but how these features apply to 3D migration is not clear. We find that lamellipodia-like protrusions and retrograde actin flow are indeed observed in cells moving in 3D ECM. However, Rab-coupling protein (RCP)-driven endocytic recycling of α5β1 integrin enhances invasive migration of cancer cells into fibronectin-rich 3D ECM, driven by RhoA and filopodial spike-based protrusions, not lamellipodia. Furthermore, we show that actin spike protrusions are Arp2/3-independent. Dynamic actin spike assembly in cells invading in vitro and in vivo is regulated by Formin homology-2 domain containing 3 (FHOD3), which is activated by RhoA/ROCK, establishing a novel mechanism through which the RCP–α5β1 pathway reprograms the actin cytoskeleton to promote invasive migration and local invasion in vivo. 相似文献
85.
Vladimir Naumov Evgeny Putin Stefan Pushkov Ekaterina Kozlova Konstantin Romantsov Alexander Kalashnikov Fedor Galkin Nina Tihonova Anastasia Shneyderman Egor Galkin Arsenii Zinkevich Stephanie M. Cope Ramanathan Sethuraman Tudor I. Oprea Alexander T. Pearson Savas Tay Nishant Agrawal Alexey Dubovenko Quentin Vanhaelen Ivan Ozerov Alex Aliper Evgeny Izumchenko Alex Zhavoronkov 《PLoS computational biology》2021,17(7)
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Isachenko V Isachenko E Katkov II Montag M Dessole S Nawroth F Van Der Ven H 《Biology of reproduction》2004,71(4):1167-1173
Human spermatozoa can be successfully cryopreserved avoiding the use of cryoprotectants through vitrification at very high cooling rates (up to 7.2 x 10(5) degrees C/min). This is achieved by directly plunging a copper cryoloop loaded with a sperm suspension into liquid nitrogen. After storage, vitrified spermatozoa are instantly thawed by melting in an agitated, warm medium. The goal of the present study was to compare the quality of spermatozoa cryopreserved using this rapid vitrification method with that of spermatozoa cooled relatively slowly by preexposure of the loaded cryoloop to liquid nitrogen vapor (-160 degrees C) with speed in the range 150-250 degrees C/min) before immersion into liquid nitrogen. Both cooling modes led to comparable results in terms of the motility, fertilization ability, and DNA integrity of the warmed spermatozoa. In both cases, instant thawing by melting in a warm medium was essential for successful cryopreservation. Our findings suggest that optimal regimes for the cryoprotectant-free cryopreservation of spermatozoa need not be restricted to very fast cooling before storage in liquid nitrogen, a wide range of cooling rates being acceptable. Herein, we discuss the implications of this finding in the light of the physics of extra- and intracellular vitrification. 相似文献
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E V Gurevich N V Bobkova Iu A Katkov N A Otmakhova I V Nesterova 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1992,42(4):779-787
Ablation of the olfactory bulbs in mice C57Bl/6j was accompanied by motor and orienting-exploratory activity augmentation in the "open field" test and deterioration of the learning ability to active and passive avoidance. The most expressed behavioural changes developed in four weeks after the surgery. Chronic administration of antidepressants (amitriptyline, 20 mg/kg; trazodone, 20 mg/kg; imipramine, 10 mg/kg; intraperitoneally) normalized behaviour of bulbectomized animals, trazodone being the most effective. In the biochemical studies the brainstem serotonin level was found to be decreased and the density of 5HT2-receptors in the cerebral cortex increased in bulbectomized mice. Only trazodone was able to correct the biochemical indices. The state of the bulbectomized mice is supposed to serve a model of a depression with hypo-function of serotonergic system of the brain. 相似文献
90.