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211.
Ani Michaud Marcin Leda Zachary T. Swider Songeun Kim Jiaye He Jennifer Landino Jenna R. Valley Jan Huisken Andrew B. Goryachev George von Dassow William M. Bement 《The Journal of cell biology》2022,221(8)
Many cells can generate complementary traveling waves of actin filaments (F-actin) and cytoskeletal regulators. This phenomenon, termed cortical excitability, results from coupled positive and negative feedback loops of cytoskeletal regulators. The nature of these feedback loops, however, remains poorly understood. We assessed the role of the Rho GAP RGA-3/4 in the cortical excitability that accompanies cytokinesis in both frog and starfish. RGA-3/4 localizes to the cytokinetic apparatus, “chases” Rho waves in an F-actin–dependent manner, and when coexpressed with the Rho GEF Ect2, is sufficient to convert the normally quiescent, immature Xenopus oocyte cortex into a dramatically excited state. Experiments and modeling show that changing the ratio of RGA-3/4 to Ect2 produces cortical behaviors ranging from pulses to complex waves of Rho activity. We conclude that RGA-3/4, Ect2, Rho, and F-actin form the core of a versatile circuit that drives a diverse range of cortical behaviors, and we demonstrate that the immature oocyte is a powerful model for characterizing these dynamics. 相似文献
212.
Monteiro RA Balsanelli E Tuleski T Faoro H Cruz LM Wassem R de Baura VA Tadra-Sfeir MZ Weiss V DaRocha WD Muller-Santos M Chubatsu LS Huergo LF Pedrosa FO de Souza EM 《FEMS microbiology ecology》2012,80(2):441-451
Herbaspirillum rubrisubalbicans M1 causes the mottled stripe disease in sugarcane cv. B-4362. Inoculation of this cultivar with Herbaspirillum seropedicae SmR1 does not produce disease symptoms. A comparison of the genomic sequences of these closely related species may permit a better understanding of contrasting phenotype such as endophytic association and pathogenic life style. To achieve this goal, we constructed suppressive subtractive hybridization (SSH) libraries to identify DNA fragments present in one species and absent in the other. In a parallel approach, partial genomic sequence from H.?rubrisubalbicans M1 was directly compared in silico with the H.?seropedicae SmR1 genome. The genomic differences between the two organisms revealed by SSH suggested that lipopolysaccharide and adhesins are potential molecular factors involved in the different phenotypic behavior. The cluster wss probably involved in cellulose biosynthesis was found in H.?rubrisubalbicans M1. Expression of this gene cluster was increased in H.?rubrisubalbicans M1 cells attached to the surface of maize root, and knockout of wssD gene led to decrease in maize root surface attachment and endophytic colonization. The production of cellulose could be responsible for the maize attachment pattern of H.?rubrisubalbicans M1 that is capable of outcompeting H.?seropedicae SmR1. 相似文献
213.
Adrian Oo Keivan Zandi Caitlin Shepard Leda C. Bassit Katie Musall Shu Ling Goh Young-Jae Cho Dong-Hyun Kim Raymond F. Schinazi Baek Kim 《The Journal of biological chemistry》2022,298(3)
The lack of antiviral innate immune responses during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is characterized by limited production of interferons (IFNs). One protein associated with Aicardi–Goutières syndrome, SAMHD1, has been shown to negatively regulate the IFN-1 signaling pathway. However, it is unclear whether elevated IFN signaling associated with genetic loss of SAMHD1 would affect SARS-CoV-2 replication. In this study, we established in vitro tissue culture model systems for SARS-CoV-2 and human coronavirus OC43 infections in which SAMHD1 protein expression was absent as a result of CRISPR–Cas9 gene KO or lentiviral viral protein X–mediated proteosomal degradation. We show that both SARS-CoV-2 and human coronavirus OC43 replications were suppressed in SAMHD1 KO 293T and differentiated THP-1 macrophage cell lines. Similarly, when SAMHD1 was degraded by virus-like particles in primary monocyte-derived macrophages, we observed lower levels of SARS-CoV-2 RNA. The loss of SAMHD1 in 293T and differentiated THP-1 cells resulted in upregulated gene expression of IFNs and innate immunity signaling proteins from several pathways, with STAT1 mRNA being the most prominently elevated ones. Furthermore, SARS-CoV-2 replication was significantly increased in both SAMHD1 WT and KO cells when expression and phosphorylation of STAT1 were downregulated by JAK inhibitor baricitinib, which over-rode the activated antiviral innate immunity in the KO cells. This further validates baricitinib as a treatment of SARS-CoV-2–infected patients primarily at the postviral clearance stage. Overall, our tissue culture model systems demonstrated that the elevated innate immune response and IFN activation upon genetic loss of SAMHD1 effectively suppresses SARS-CoV-2 replication. 相似文献
214.
215.
VA Weiss H Faoro MZ Tadra-Sfeir RT Raittz EM de Souza RA Monteiro RL Cardoso R Wassem LS Chubatsu LF Huergo M Müller-Santos MB Steffens LU Rigo Fde O Pedrosa LM Cruz 《Journal of bacteriology》2012,194(15):4136-4137
Herbaspirillum lusitanum strain P6-12 (DSM 17154) is, so far, the only species of Herbaspirillum isolated from plant root nodules. Here we report a draft genome sequence of this organism. 相似文献
216.
In the current literature, information is scarce on which part of the adult insect body is suitable for isolation of genomic DNA for genetic analysis based on DNA-markers. In this study, we evaluated RAPD profiles generated from total genomic DNA isolated from distinct body parts (head, legs, thorax + wings and abdomen) of 12 males of Euglossa pleosticta Dressler. From the total of bands analyzed, 9.0% did not show reproducibility. Percent variations of bands in each body segment were: 1.1% (head); 0.4% (legs); 0.8% (thorax/wings) and 6.7% (abdomen). The much higher variation (chi2(one sample) = 10.27; df = 1; P < 0.01) in the RAPD profiles obtained by using DNA isolated from abdomen of the euglossine males suggests that this body part of adult insects should be avoided in DNA extraction procedures. Conversely, the low variation among the RAPD profiles obtained from amplifications of genomic DNA extracted from head, legs and thorax/wings indicates that all these body parts of male bees are equally useful and secure for using in isolation and amplification procedures of total genomic DNA. 相似文献
217.
218.
André L. F. Souza Adriana L. Invitti Fabiane G. M. Rego Rose A. Monteiro Giseli Klassen Emanuel M. Souza Leda S. Chubatsu Fábio O. Pedrosa Liu U. Rigo 《Journal of microbiology (Seoul, Korea)》2010,48(1):77-83
The pathway of electron transport to nitrogenase in the endophytic β-Proteobacterium Herbaspirillum seropedicae has not been characterized. We have generated mutants in two nif-associated genes encoding putative ferredoxins, fdxA and fdxN. The fdxA gene is part of the operon nifHDKENXorf1orf2fdxAnifQmodABC and is transcribed from the nifH promoter, as revealed by lacZ gene fusion. The fdxN gene is probably cotranscribed with the nifB gene. Mutational analysis suggests that the FdxA protein is essential for maximum nitrogenase activity, since the nitrogenase
activity of the fdxA mutant strain was reduced to about 30% of that of the wild-type strain. In addition, the fdxA mutation had no effect on the nitrogenase switch-off in response to ammonium. Nitrogenase activity of a mutant strain lacking
the fdxN gene was completely abolished. This phenotype was reverted by complementation with fdxN expressed under lacZ promoter control. The results suggest that the products of both the fdxA and fdxN genes are probably involved in electron transfer during nitrogen fixation. 相似文献
219.
Mutants of Pseudomonas aeruginosa deficient in the utilization of l-proline as the only carbon and nitrogen source have been found to be defective either in proline dehydrogenase activity or in both proline dehydrogenase and 1-pyrroline-5-carboxylate dehydrogenase activities of the bifunctional proline degradative enzyme. The latter type of mutants was unable to utilize l-ornithine, indicating that a single 1-pyrroline-5-carboxylate dehydrogenase activity is involved in the degradation of ornithine and proline. Proline dehydrogenase and 1-pyrroline-5-carboxylate dehydrogenase activities were strongly and coordinately induced by proline. It was excluded that 1-pyrroline-5-carboxylate acted as an inducer of the bifunctional enzyme and it was shown that the low level induction observed during growth on ornithine was due to the intracellular formation of proline. The formation of the proline degradative enzyme was shown to be subject to catabolite repression by citrate and nitrogen control.Abbreviations EMS
Ethylmethane sulfonate
- NG
N-methyl-N-nitro-N-nitrosoguanidine
- P
Minimal medium P
- Pro-DH
Proline dehydro-genase
- P5C
1-Pyrroline-5-carboxylate
- P5C-DH
1-Pyrroline-5-carboxylate dehydrogenase 相似文献
220.
We examined the effects of soil mesofauna and the litter decomposition environment (above and belowground) on leaf decomposition rates in three forest types in southeastern Brazil. To estimate decomposition experimentally, we used litterbags with a standard substrate in a full-factorial experimental design. We used model selection to compare three decomposition models and also to infer the importance of forest type, decomposition environment, mesofauna, and their interactions on the decomposition process. Rather than the frequently used simple and double-exponential models, the best model to describe our dataset was the exponential deceleration model, which assumed a single organic compartment with an exponential decrease of the decomposition rate. Decomposition was higher in the wet than in the seasonal forest, and the differences between forest types were stronger aboveground. Regarding litter decomposition environment, decomposition was predominantly higher below than aboveground, but the magnitude of this effect was higher in the seasonal than in wet forests. Mesofauna exclusion treatments had slower decomposition, except aboveground into the Semi-deciduous Forest, where the mesofauna presence did not affect decomposition. Furthermore, the effect of mesofauna was stronger in the wet forests and belowground. Overall, our results suggest that, in a regional scale, both decomposers activity and the positive effect of soil mesofauna in decomposition are constrained by abiotic factors, such as moisture conditions. 相似文献