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431.
LytM factors affect the recruitment of autolysins to the cell division site in Caulobacter crescentus 下载免费PDF全文
Aleksandra Zielińska Maria Billini Andrea Möll Katharina Kremer Ariane Briegel Adrian Izquierdo Martinez Grant J. Jensen Martin Thanbichler 《Molecular microbiology》2017,106(3):419-438
Most bacteria possess a peptidoglycan cell wall that determines their morphology and provides mechanical robustness during osmotic challenges. The biosynthesis of this structure is achieved by a large set of synthetic and lytic enzymes with varying substrate specificities. Although the biochemical functions of these proteins are conserved and well‐investigated, the precise roles of individual factors and the regulatory mechanisms coordinating their activities in time and space remain incompletely understood. Here, we comprehensively analyze the autolytic machinery of the alphaproteobacterial model organism Caulobacter crescentus, with a specific focus on LytM‐like endopeptidases, soluble lytic transglycosylases and amidases. Our data reveal a high degree of redundancy within each protein family but also specialized functions for individual family members under stress conditions. In addition, we identify two lytic transglycosylases and an amidase as new divisome components that are recruited to midcell at distinct stages of the cell cycle. The midcell localization of these proteins is affected by two LytM factors with degenerate catalytic domains, DipM and LdpF, which may serve as regulatory hubs coordinating the activities of multiple autolytic enzymes during cell constriction and fission respectively. These findings set the stage for in‐depth studies of the molecular mechanisms that control peptidoglycan remodeling in C. crescentus. 相似文献
432.
Neutrophil extracellular trap formation in the Streptococcus suis‐infected cerebrospinal fluid compartment 下载免费PDF全文
433.
A comparison between Ca and Sr cycling in forest ecosystems 总被引:8,自引:1,他引:7
In favourable conditions, the 87Sr/86Sr isotope ratios of the Sr delivered by rain and soil mineral weathering differ. Assuming that Ca and Sr behave similarly
in forest ecosystems, several authors have used the 87Sr/86Sr variation in forest compartments to calculate the contribution of rain and mineral weathering to Ca fluxes and pools. However,
there are a number of experimental reports showing that Ca and Sr may behave differently in the soil and in the plant. We
have tested this Ca–Sr analogy in the field by measuring the variation of Sr and Ca concentrations, fluxes and pools in spruce,
beech and maple stands on granite, sandstone and limestone. Results show that (1) variations of Ca and Sr concentrations are
generally correlated at each level of the ecosystems. (2) In spruce on acid soils, a preferential uptake of Ca over Sr occurs
(Aubure spruce Sr/Ca = 0.8×10−3; soil exchangeable Sr/Ca between 2 and 6×10−3). On calcareous soils, a preferential uptake of Sr over Ca by spruce may occur. (3) In spruce and beech on acid and calcareous
soils, a preferential translocation of Ca over Sr from roots to leaves occurs ((Sr/Ca) in leaves was between 10 and 90% of
that in roots). (4) The biological cycling of Ca and Sr leads to an enrichment of the upper soil layers in Ca and Sr. Compared
to Sr, Ca accumulates in the upper layer of acid soils because Ca cycling through litterfall is favoured over Sr cycling,
and possibly because of the selectivity of acid organic exchangers for Ca.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
434.
Marc Bartoli Jean‐Pierre Ternaux Claude Forni Paule Portalier Pascal Salin Marianne Amalric Ariane Monneron 《Developmental neurobiology》1999,40(2):234-243
Striatin, an intraneuronal, calmodulin‐binding protein addressed to dendrites and spines, is expressed in the motor system, particularly the striatum and motoneurons. Striatin contains a high number of domains mediating protein–protein interactions, suggesting a role within a dendritic Ca2+‐signaling pathway. Here, we explored the hypothesis of a direct role of striatin in the motor control of behaving rats, by using an antisense strategy based on oligodeoxynucleotides (ODN). Rats were treated by intracerebroventricular infusion of a striatin antisense ODN (A‐ODN) or mismatch ODN (M‐ODN) delivered by osmotic pumps over 6 days. A significant decrease in the nocturnal locomotor activity of A‐ODN–treated rats was observed after 5 days of treatment. Hypomotricity was correlated with a 60% decrease in striatin content of the striata of A‐ODN–treated rats sacrificed on day 6. Striatin thus plays a role in the control of motor function. To approach the cellular mechanisms in which striatin is involved, striatin down‐regulation was studied in a comparatively simpler model: purified rat spinal motoneurons which retain their polarity in culture. Treatment of cells by the striatin A‐ODN resulted in the impairement of the growth of dendrites but not axon. The decrease in dendritic growth paralleled the loss of striatin. This model allows analysis of the molecular basis of striatin function in the dynamic changes occurring in growing dendrites, and offers clues to unravel its function within spines. © 1999 John Wiley & Sons, Inc. J Neurobiol 40: 234–243, 1999 相似文献
435.
Miguel Tillo William C. Lamanna Chrissa A. Dwyer Daniel R. Sandoval Ariane R. Pessentheiner Norah Al-Azzam Stphane Sarrazin Jon C. Gonzales Shih-Hsin Kan Alexander Y. Andreyev Nicholas Schultheis Bryan E. Thacker Charles A. Glass Patricia I. Dickson Raymond Y. Wang Scott B. Selleck Jeffrey D. Esko Philip L.S.M. Gordts 《The Journal of biological chemistry》2022,298(8)
Lysosomal storage diseases result in various developmental and physiological complications, including cachexia. To study the causes for the negative energy balance associated with cachexia, we assessed the impact of sulfamidase deficiency and heparan sulfate storage on energy homeostasis and metabolism in a mouse model of type IIIa mucopolysaccharidosis (MPS IIIa, Sanfilippo A syndrome). At 12-weeks of age, MPS IIIa mice exhibited fasting and postprandial hypertriglyceridemia compared with wildtype mice, with a reduction of white and brown adipose tissues. Partitioning of dietary [3H]triolein showed a marked increase in intestinal uptake and secretion, whereas hepatic production and clearance of triglyceride-rich lipoproteins did not differ from wildtype controls. Uptake of dietary triolein was also elevated in brown adipose tissue (BAT), and notable increases in beige adipose tissue occurred, resulting in hyperthermia, hyperphagia, hyperdipsia, and increased energy expenditure. Furthermore, fasted MPS IIIa mice remained hyperthermic when subjected to low temperature but became cachexic and profoundly hypothermic when treated with a lipolytic inhibitor. We demonstrated that the reliance on increased lipid fueling of BAT was driven by a reduced ability to generate energy from stored lipids within the depot. These alterations arose from impaired autophagosome–lysosome fusion, resulting in increased mitochondria content in beige and BAT. Finally, we show that increased mitochondria content in BAT and postprandial dyslipidemia was partially reversed upon 5-week treatment with recombinant sulfamidase. We hypothesize that increased BAT activity and persistent increases in energy demand in MPS IIIa mice contribute to the negative energy balance observed in patients with MPS IIIa. 相似文献
436.
Mohammed Kaplan Catherine M. Oikonomou Cecily R. Wood Georges Chreifi Debnath Ghosal Megan J. Dobro Qing Yao Ritesh Ranjan Pal Amit K. Baidya Yuxi Liu Stefano Maggi Alasdair W. McDowall Sigal Ben-Yehuda Ilan Rosenshine Ariane Briegel Morgan Beeby Yi-Wei Chang Carrie L. Shaffer Grant J. Jensen 《Journal of bacteriology》2022,204(8)
437.
438.
Stabilization of bacteriophage Mu repressor-operator complexes by the Escherichia coli integration host factor protein 总被引:4,自引:0,他引:4
All of the previously described effects of integration host factor (IHF) on bacteriophage Mu development have supported the view that IHF favours transposition-replication over the alternative state of lysogenic phage growth. In this report we show that, consistent with a model in which Mu repressor binding to its operators requires a particular topology of the operator DNA, IHF stimulates repressor binding to the O1 and O2 operators and enhances Mu repression. IHF would thus be one of the keys, besides supercoiling and the H-NS protein, that lock the operator region into the appropriate topological conformation for high-affinity binding not only of the phage transposase but also of the phage repressor. 相似文献
439.
Ariane I. de Agostini Marie-Andre Ramus Robert D. Rosenberg 《Journal of cellular biochemistry》1994,54(2):174-185
The heparan sulfate proteoglycans that bind and activate antithrombin III (aHSPGs) are synthesized by endothelial cells as well as other nonvascular cells. We determined the amounts of cell surface–associated and soluble aHSPGs generated by the rat fat pad endothelial (RFP) cell line and the fibroblast (LTA) cell line. The RFP cells exhibit higher levels of cell surface–associated aHSPGs as compared to LTA cells, whereas LTA cells release larger amounts of soluble aHSPGs as compared to RFP cells. After confluence RFP cells show an increase in both cell surface–associated and soluble aHSPGs. In contrast, postconfluent LTA cells maintain a constant level of cell surface–associated and soluble aHSPGs. These observations indicate that different cells types can preferentially accumulate aHSPGs as cell surface–associated or soluble forms which could reflect alternate biological functions. 相似文献
440.