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861.
The specific interaction between rhizobia and legume roots leads to the development of a highly regulated process called nodulation, by which the atmospheric nitrogen is converted into an assimilable plant nutrient. This capacity is the basis for the use of bacterial inoculants for field crop cultivation. Legume plants have acquired tools that allow the entry of compatible bacteria. Likewise, plants can impose sanctions against the maintenance of nodules occupied by rhizobia with low nitrogen-fixing capacity. At the same time, bacteria must overcome different obstacles posed first by the environment and then by the legume. The present review describes the mechanisms involved in the regulation of the entire legume–rhizobium symbiotic process and the strategies and tools of bacteria for reaching the nitrogen-fixing state inside the nodule. Also, we revised different approaches to improve the nodulation process for a better crop yield. 相似文献
862.
Silicoflagellates, large heterotrophic dinoflagellates, radiolarians,tintinnids and micro-crustaceans were counted in 72 screened(15 µm) samples retrieved at 0150 m from the WeddellSea in January 1989. Tintinnid species were identified and biomassestimates were carried out for all groups on the basis of measurementsof cell dimensions. Dinoflagellates dominated the micro-heterotrophiccommunity at all stations and depths (65% of overall microzooplanktoniccarbon in the 0150 m interval), followed by the tintinnids(18%), microcrustaceans (16%) and radiolarians (1%). All groups,with the exception of silicoflagellates, peaked noticeably inthe vicinity of the southern end of the transect (7677°S).Relationships between concentrations of chlorophyll a and microzooplanktonicbiomass were present, yet not altogether consistent, but bothphyto- and microzooplankton seemed to generally respond to regionalenhancements associated with the ice edge. Comparison with similarWeddell and Weddell-Scotia data retrieved in February-March1987 and November 1988-December 1989, respectively, are highlycoherent in terms of microplanktonic abundances, their geographicand vertical distribution patterns, and the specific make-upand distribution of tintinnid assemblages. Analyses of the oraldiameters of tintinnid morphotypes suggest that the latitudinaland vertical distribution of their five dominant taxa (whichaccount for >90% of all individuals) is structured so asto maximize resource partitioning. 相似文献
863.
Giuseppe Carruba Bruno Dallapiccola Viviana Brinchi Carlo De Giuli Morghen 《In vitro cellular & developmental biology. Plant》1983,19(6):443-452
Summary A human diploid cell line of choroid origin was isolated from the retrouveal portion of an enucleated eye and designated HC.
After 10 passages, when the proliferative capacity of HC cells decreased, they were infected and transformed by Simian Virus
40 (SV40). A proliferating long-term cultured cell line designated HC/SV40 was established and it has been maintained as monolayer
for more than 100 passages so far. The two cell lines, HC and HC/SV40, were compared for growth characteristics, capacity
to form colonies in soft agar, presence of nuclear T-antigen, and ultrastructure. Cytogenetic analysis was also performed
to determine the presence of chromosomal aberrations due to the permanent viral transformation of the cell line.
The results indicate that HC/SV40 should be considered the transformed counterparts of HC cells because they are morphologically
similar to the latter but can grow in soft agar, possess T-antigen, and show a pattern of karyotypic changes similar to that
induced by SV40 in human fibroblasts. The choroid origin of HC and HC/SV40 cell lines was confirmed by the presence, in their
cytoplasm, of typical electron dense granules. Their neural origin will make these cell lines very useful for neuropharmacological
and differentiation studies.
This work was supported by Grant 82.00346.96 from the C.N.R. finalized project “Control of Neoplastic Growth”. 相似文献
864.
Riccardo Fedeli Andrea Vannini Silvia Celletti Viviana Maresca Silvana Munzi Cristina Cruz Dmitry Alexandrov Massimo Guarnieri Stefano Loppi 《The Annals of applied biology》2023,182(1):57-64
In the quest for eco-friendly products with biostimulant properties, foliar application of wood distillate (WD) was tested on the growth and yield of chickpea (Cicer arietinum L.). WD (pyroligneous acid) is a by-product of plant biomass pyrolysis and is rich in biologically active substances like polyphenols, alcohols, acids and esters. In this work, chickpea plants were sprayed weekly with 100 ml 0.25% (v/v) chestnut (Castanea sativa Mill.) WD during the whole growing period, and at the end physiological and nutritional analyses were performed both on the whole plant and on seeds. While plant height and weight did not change significantly, seeds showed an increase in diameter (+11.2%) and weight (+33.3%), and in the content of starch (+45.9%), total soluble protein (+12.9%), total polyphenol (+16.4%) and antioxidant power (+28.4%). Overall, the content of essential free amino acids increased, except for lysine (−3.4%), phenylalanine (−10.5%) and methionine (−13.7%). Among all the mineral elements analysed, only potassium and magnesium decreased in WD-treated plants, although values were within the common range for chickpea seeds. These results are a clear demonstration of the effectiveness of the use of WD on increasing the nutritional qualities of the edible parts of crop species, thus representing a possible solution to counteract human malnutrition and famine as well as environmental concerns. 相似文献
865.
Ondrej Chlumsky Sabina Purkrtova Hana Michova Viviana Svarcova Petr Slepicka Dominik Fajstavr 《Biofouling》2020,36(2):222-233
AbstractThe antimicrobial activity of gold and silver nanoparticles (AuNPs, AgNPs), chitosan (CS) and their combinations was established by determining the minimum inhibitory concentration for planktonic (MICPC80) and biofilm growth (MICBC80), for biofilm formation (MICBF80), metabolic activity (MICBM80) and reduction (MICBR80), and for the metabolic activity of preformed biofilm (MICMPB80). Biofilms were quantified in microtitre plates by crystal violet staining and metabolic activity was evaluated by the MTT assay. Chitosan effectively suppressed biofilm formation (0.31–5?mg ml?1) in all the tested strains, except Salmonella enterica Infantis (0.16–2.5?mg ml?1) where CS and its combination with AgNPs induced biofilm formation. Nanoparticles inhibited biofilm growth only when the highest concentrations were used. Even though AuNPs, AgNPs and CS were not able to remove biofilm mass, they reduced its metabolic activity by at least 80%. The combinations of nanoparticles with CS did not show any significant positive synergistic effect on the tested target properties. 相似文献
866.
Sylvain Losdat Fabrice Helfenstein Jonathan D. Blount Viviana Marri Lea Maronde Heinz Richner 《Biology letters》2013,9(1)
Stressful conditions experienced by individuals during their early development have long-term consequences on various life-history traits such as survival until first reproduction. Oxidative stress has been shown to affect various fitness-related traits and to influence key evolutionary trade-offs but whether an individual''s ability to resist oxidative stress in early life affects its survival has rarely been tested. In the present study, we used four years of data obtained from a free-living great tit population (Parus major; n = 1658 offspring) to test whether pre-fledging resistance to oxidative stress, measured as erythrocyte resistance to oxidative stress and oxidative damage to lipids, predicted fledging success and local recruitment. Fledging success and local recruitment, both major correlates of survival, were primarily influenced by offspring body mass prior to fledging. We found that pre-fledging erythrocyte resistance to oxidative stress predicted fledging success, suggesting that individual resistance to oxidative stress is related to short-term survival. However, local recruitment was not influenced by pre-fledging erythrocyte resistance to oxidative stress or oxidative damage. Our results suggest that an individual ability to resist oxidative stress at the offspring stage predicts short-term survival but does not influence survival later in life. 相似文献
867.
868.
Viviana Job Gianluca Molla Mirella S Pilone Loredano Pollegioni 《European journal of biochemistry》2002,269(5):1456-1463
We have cloned the gene coding for the Bacillus subtilis glycine oxidase (GO), a new flavoprotein that oxidizes glycine and sarcosine to the corresponding alpha-keto acid, ammonia and hydrogen peroxide. By inserting the DNA encoding for GO into the multiple cloning site of the expression vector pT7.7 we produced a recombinant plasmid (pT7-GO). The pT7-GO encodes a fully active fusion protein with six additional residues at the N-terminus of GO (MARIRA). In BL21(DE3)pLysS Escherichia coli cells, and under optimal isopropyl thio-beta-D-galactoside induction conditions, soluble and active chimeric GO was expressed up to 1.14 U g(-1) of cell (and a fermentation yield of 3.82 U x L(-1) of fermentation broth). An N-terminal His-tagged protein (HisGO) was also successfully expressed in E. coli as a soluble protein and a fully active holoenzyme. HisGO represents approximately 3.9% of the total soluble protein content of the cell. The His-tagged GO was purified in a single step by nickel-chelate chromatography to a specific activity of 1.06 U x mg(-1) protein at 25 degrees C and with a yield of 98%. The characterization of the purified enzyme showed that GO is a homotetramer of approximately 180 kDa with the spectral properties typical of flavoproteins. GO exhibits good thermal stability, with a Tm of 46 degrees C after 30 min incubation; its stability is maximal in the 7.0-8.5 pH range. A comparison of amino-acid sequence and substrate specificity indicates that GO has similarities to other flavoenzymes acting on primary amines and on D-amino acids. 相似文献
869.
Díaz-Barrera Alvaro Urtuvia Viviana Padilla-Córdova Claudio Peña Carlos 《Journal of industrial microbiology & biotechnology》2019,46(1):13-19
Journal of Industrial Microbiology & Biotechnology - Azotobacter vinelandii OP is a bacterium that produces poly(3-hydroxybutyrate) (PHB). PHB production in a stirred bioreactor, at different... 相似文献