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31.
32.
The ultrastructure, morphology, and histology of somatic embryogenesis in pearl millet (Pennisetum glaucum) were examined using light and electron microscopic techniques. Somatic embryogenesis was initiated from zygotic embryo explants cultured 8 d after pollination. Formation of a ridge of tissue began 3–4 d after culture (DAC) by divisions in the epidermal and subepidermal cells of the scutellum. Ridge formation was accompanied by a decrease in vacuoles, lipid bodies, and cell size, and an increase in endoplasmic reticulum (ER). Proembryonic cell masses (proembryoids) formed from the scutellar ridge by 10 DAC. Proembryoid cells had abundant Golgi bodies and ER while the amounts of lipids and starch varied. Somatic embryos developed from the proembryonic masses 13 DAC and by 21 DAC had all the parts of mature zygotic embryos. Although shoot and root primordia of somatic embryos were always less differentiated than those of zygotic embryos, scutellar cells of somatic and zygotic embryos had similar amounts of lipids, vacuoles, and starch. Somatic scutellar epidermal cells were more vacuolated than their zygotic counterparts. In contrast, somatic scutellar nodal cells were smaller and not as vacuolated as in zygotic embryos. Somatic embryogenesis was characterized by three phases of cell development: first, scutellar cell dedifferentiation with a reduction in lipids and cell and vacuole size; second, proembryoid formation with high levels of ER; and third, the development of somatic embryos that were functionally and morphologically similar to zygotic embryos. 相似文献
33.
I.A. Tsaplina A.E. Zhuravlev M.A. Egorova T.I. Bogdanov E.N. Krasil’nikova L.M. Zakharchuk T.F. Kondrat’ev 《Microbiology》2010,79(1):13-22
For cultures of moderately thermophilic chemolithotrophic bacteria Sulfobacillus sibiricus N1 and SSO, S. thermosulfidooxidans subsp. asporogenes 41, and the thermotolerant strain S. thermotolerans Kr1 grown under forced aeration and in a high medium layer without aeration, growth characteristics, substrate consumption, and exometabolite formation were compared. Sulfobacilli grown under oxygen limitation exhibited greater generation time, longer growth period, cell yield decreased by from 40 to 85% (depending on the strain), suppressed cell respiration ( demonstrated for S. sibiricus N1 ), accumulation of exometabolites (acetate and propionate) in the medium, and emergence of resting forms. For strains N1, SSO, and Kr1, oscillations of Fe(II) and Fe(III) content in the medium were revealed. For S. sibiricus N1 and S. thermotolerans Kr1, grown under hypoxia (0.07% O2 in the gas phase), coupling of substrate oxidation with Fe(III) reduction was revealed, as well as utilization of Fe(III) as an electron acceptor alternative to oxygen. The role of labile energy and constructive metabolism for survival of sulfobacilli under diverse conditions is discussed. 相似文献
34.
Alekseyev S. S. Pichugin M. Yu. Gordeeva N. V. Samusenok V. P. Yur’ev A. L. Khlystov V. S. Matveev A. N. 《Journal of Ichthyology》2019,59(4):527-544
Journal of Ichthyology - In the system of lakes Bol’shoe Leprindo and Maloe Leprindo (Lena basin, Transbaikalia), spawning of two isolated populations of the dwarf form of Arctic charr... 相似文献
35.
Indra K. Vasil 《In vitro cellular & developmental biology. Plant》2008,44(5):365-372
The International Association for Plant Biotechnology (IAPB) was founded in 1963 at the first truly international conference
on plant tissue culture, which was organized by Philip R. White. White was a devoted internationalist and was strongly committed
to global scientific cooperation. He felt that the time had come for the international tissue culture community to organize
so that it could meet regularly and provide a forum to its members for the exchange of ideas and information of mutual interest
and use. The various activities of the IAPB since its founding—the publication of its newsletter, its journal, and the proceedings
of its quadrennial congresses—faithfully document the remarkable advances in plant biotechnology that were made possible by
the successful integration of tissue culture and molecular biology. In particular, the congress proceedings serve as time
capsules, providing a wealth of information about the best of science and the most prominent scientists of the time. The history
of the IAPB is indeed the history of plant biotechnology. 相似文献
36.
Exposure of cells to ultraviolet radiation (UVR) is one of the best studied and most used model system for the examination
of the biological effects of DNA damage, its repair and tolerance. The major product after UVR treatment is cyclobutane pyrimidine
dimer (TT, TC, CC). Pyrimidine dimers are repaired by a direct reversal called photoreactivation or by excision of damage
in a process of nucleotide excision repair. Several methods have been developed for the detection and quantification of pyrimidine
dimers in DNA. The technique of Small and Greimann, in which DNA is incubated with the pyrimidine dimer-specific endonuclease,
was used for the analysis of mutant strains with impaired excision repair system of the unicellular green alga Chlamydomonas reinhardtii. Another method is based on the binding of specific monoclonal antibodies to pyrimidine dimers. The aim of our work was to
compare these two techniques with the use of mutant strains of C. reinhardtii — uvsX1 and uvsX2 which are assumed to be deficient in DNA damage recognition. One of their traits was sensitivity to UVR which could be caused
by breakdown of the excision repair pathway. The results suggest that the immuno-approach is suitable for the detection of
DNA damage induced by UVR.
Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia. 相似文献
37.
38.
Vasil Pirgozliev Stephen C. Mansbridge Izzy M. Whiting Stephen P. Rose Kristina Kljak Amy E. Johnson Falko Drijfhout Sylwia Orczewska-Dudek Atanas G. Atanasov Teodora Mihova 《The Annals of applied biology》2023,183(1):7-14
The aim of this study was to assess the effects of graded levels (0, 3, 6, 9 and 12 g/kg) of dry Sea buckthorn (SB) berries on growth performance, gastrointestinal tract (GIT) development, jejunal histomorphology, bird antioxidant status and caecal short-chain fatty acid concentration when fed to female Ross 308 broiler chickens. In addition, expression of cytokine biomarker genes in the jejunum was evaluated. The five experimental diets were fed from 7 to 21 days age to 8 pens (two birds in each) following randomisation. Feeding SB did not influence bird growth performance (p > .05). There was a linear decrease in butyric, acetic and valeric acid concentrations in caecal digesta (p < .05) and a decrease (p < .05) in crypt depth. The expression of IFNG and CD40LG responded quadratically (p < .05), peaking at 6–9 g/kg dietary inclusion of SB, respectively. Other studied variables were not affected by dietary SB inclusion (p > .05). Feeding dry SB berries up to 12 g/kg of diet did not improve the zootechnical variables of healthy commercial-strain broilers in this study. 相似文献
39.
A. Y. Arkhipova M. A. Nosenko N. V. Malyuchenko R. V. Zvartsev A. M. Moisenovich A. S. Zhdanova T. V. Vasil’eva E. A. Gorshkova I. I. Agapov M. S. Drutskaya S. A. Nedospasov M. M. Moisenovich 《Biochemistry. Biokhimii?a》2016,81(11):1251-1260
The process of tissue regeneration following damage takes place with direct participation of the immune system. The use of biomaterials as scaffolds to facilitate healing of skin wounds is a new and interesting area of regenerative medicine and biomedical research. In many ways, the regenerative potential of biological material is related to its ability to modulate the inflammatory response. At the same time, all foreign materials, once implanted into a living tissue, to varying degree cause an immune reaction. The modern approach to the development of bioengineered structures for applications in regenerative medicine should be directed toward using the properties of the inflammatory response that improve healing, but do not lead to negative chronic manifestations. In this work, we studied the effect of microcarriers comprised of either fibroin or fibroin supplemented with gelatin on the dynamics of the healing, as well as inflammation, during regeneration of deep skin wounds in mice. We found that subcutaneous administration of microcarriers to the wound area resulted in uniform contraction of the wounds in mice in our experimental model, and microcarrier particles induced the infiltration of immune cells. This was associated with increased expression of proinflammatory cytokines TNF, IL-6, IL-1β, and chemokines CXCL1 and CXCL2, which contributed to full functional recovery of the injured area and the absence of fibrosis as compared to the control group. 相似文献
40.
Lipid contents were studied in tissue and nuclei isolated from neurons and glia of neocortex of rats under conditions of normothermia
and in the state of artificial hypobiosis caused by hypothermia-hypoxia-hypercapnia. Compared to the neocortex tissue, both
nuclear fractions were fivefold impoverished in phospholipids and cholesterol and strongly enriched with mono- and diglycerides
and fatty acids. The nuclear fractions from neurons and glia contained similar amounts of phospholipids, and only the cardiolipin
content in the neuronal nuclei was lower than in the glial nuclei. The state of artificial hypobiosis in rats led to an increase
in the cholesterol/phospholipids ratio (mol/mol) in the nuclei from the neurons and glia; amounts of cholesterol and sphingomyelin
in the nuclei from the glia were increased. The increases in the cholesterol and sphingomyelin contents and in the cholesterol/phospholipids
ratio suggest an involvement of lipid-dependent signaling systems of the nuclei in the functional response of mammalian neocortex
cells to artificial hypobiosis. 相似文献