High-fat diet intake ameliorates the expression of hedgehog signaling pathway in adult rat liver

Molecular Biology Reports - Disproportionate fatty diet intake provokes hepatic lipid accumulation that causes non-alcoholic fatty liver disease, triggering the embryonically conserved Hedgehog...     

Antibacterial Activity of RM12, a Tachykinin Derivative,Against Pseudomonas aeruginosa

International Journal of Peptide Research and Therapeutics - Bacterial infections are increasing in recent years and developing with more resistance to antibiotics. There is a need of designing...     

Correlations among oligonucleotide repeats,nucleotide substitutions,and insertion–deletion mutations in chloroplast genomes of plant family Malvaceae

The co‐occurrence of mutational events including substitutions and insertions–deletions (InDels) with oligonucleotide repeats has previously been reported for a limited number of prokaryotic, eukaryotic, and organelle genomes. In this study, the correlations among these mutational events in chloroplast genomes of species in the eudicot family Malvaceae were investigated. This study also reported chloroplast genome sequences of Hibiscus mutabilis, Malva parviflora, and Malvastrum coromandelianum. These three genomes and 16 other publicly available chloroplast genomes from 12 genera of Malvaceae were used to calculate the correlation coefficients among the mutational events at family, subfamily, and genus levels. In these comparisons, chloroplast genomes were pairwise aligned to record the substitutions and the InDels in mutually exclusive, 250nucleotide long bins. Taking one among the two genomes as a reference, the coordinate positions of oligonucleotide repeats in the reference genome were recorded. The extent of correlations among repeats, substitutions, and InDels was calculated and categorized as follows: very weak (0.1–0.19), weak (0.20–0.29), moderate (0.30–0.39), and strong (0.4–0.69). The extent of correlations ranged 0.201–0.6 between “InDels and single‐nucleotide polymorphism (SNP)”, 0.182–0.513 between “InDels and repeat” and 0.055–0.403 between “SNPs and repeats”. At family‐ and subfamily‐level comparisons, 88%–96% of the repeats showed co‐occurrence with SNPs, whereas at the genus level, 23%–86% of the repeats co‐occurred with SNPs in same bins. Our findings support the previous hypothesis suggesting the use of oligonucleotide repeats as a proxy for finding the mutational hotspots.     

Mice lacking Ran binding protein 1 are viable and show male infertility

The small GTPase Ran plays important roles in multiple aspects of cellular function. Maximal RanGAP activity is achieved with the aid of RanBP1 and/or presumably of RanBP2. Here, we show that RanBP1-knockout mice are unexpectedly viable, and exhibit male infertility due to a spermatogenesis arrest, presumably caused by down-regulation of RanBP2 during spermatogenesis. Indeed, siRNA-mediated depletion of RanBP2 caused severe cell death only in RanBP1-deficient MEFs, indicating that simultaneous depletion of RanBP1 and RanBP2 severely affects normal cell viability. Collectively, we conclude that the dramatic decrease in "RanBP" activity impairs germ cell viability and affects spermatogenesis decisively in RanBP1-knockout mice.     

Functional Analysis of the Helicobacter pylori Flagellar Switch Proteins

Helicobacter pylori uses flagellum-mediated chemotaxis to promote infection. Bacterial flagella change rotational direction by changing the state of the flagellar motor via a subcomplex referred to as the switch. Intriguingly, the H. pylori genome encodes four switch complex proteins, FliM, FliN, FliY, and FliG, instead of the more typical three of Escherichia coli or Bacillus subtilis. Our goal was to examine whether and how all four switch proteins participate in flagellation. Previous work determined that FliG was required for flagellation, and we extend those findings to show that all four switch proteins are necessary for normal numbers of flagellated cells. Furthermore, while fliY and fliN are partially redundant with each other, both are needed for wild-type levels of flagellation. We also report the isolation of an H. pylori strain containing an R54C substitution in fliM, resulting in bacteria that swim constantly and do not change direction. Along with data demonstrating that CheY-phosphate interacts with FliM, these findings suggest that FliM functions in H. pylori much as it does in other organisms.Flagellar motility is important for gastric colonization by the ulcer-causing bacterium Helicobacter pylori and also for suborgan localization within the stomach (16-18, 33, 45). Flagellar motility is regulated by a set of signal transduction proteins, collectively referred to as the chemotaxis pathway, that control the migration of microbes in response to environmental cues. This pathway is well elucidated in organisms such as Escherichia coli, Salmonella enterica serovar Typhimurium (referred to hereinafter as S. Typhimurium), and Bacillus subtilis. Sequence analysis of the genomes of other flagellated bacteria, including H. pylori, has suggested that there is diversity in the set of chemotaxis proteins that a particular microbe contains. Here we analyze the diversity of H. pylori''s flagellar switch proteins, which control flagellar rotational direction.The molecular mechanisms underlying chemotactic signal transduction in E. coli and S. Typhimurium have been extensively studied (7, 50) The overall function of this pathway is to convert the perception of local environmental conditions into a swimming response that drives bacteria toward beneficial conditions and away from harmful ones. Such migration is accomplished by interspersing straight, or smooth, swimming with periods of random reorientations or tumbles. Smooth swimming occurs when the flagella rotate counterclockwise (CCW), while reorienting occurs when the flagella rotate clockwise (CW). The chemotaxis signal transduction system acts to appropriately alter flagellar rotation. The canonical chemotaxis pathway consists of a chemoreceptor bound to the coupling protein CheW, which is in turn bound to the histidine kinase CheA. If a beneficial/attractant ligand is not bound (or a repellant is bound) to the chemoreceptor, CheA autophosphorylates and passes a phosphate to the response regulator CheY. Phosphorylated CheY (CheY-P) interacts with a protein complex called the flagellar switch (discussed at more length below). This interaction causes a switch in the direction of flagellar rotation from CCW to CW, thus reorienting the cells, via an as-yet-unknown mechanism (reviewed in references 23 and 29).Bacterial flagella are complex, multiprotein organelles (reviewed in references 23, 25, and 29). Each flagellum is composed of several parts, including the filament, the hook, and the basal body (listed from outside the cell to inside the cytoplasm). The flagellar basal body spans from the outer membrane to the cytoplasm and is responsible for rotating the flagellum. This part of the flagellum is further made up of several subassemblies that are named for their locations. The innermost is called the switch or C ring, based on its location in the cytoplasm. The switch is comprised of three proteins in E. coli, FliM, FliN, and FliG (reviewed in references 23 and 29). Experimental evidence strongly suggests that these proteins, along with the stator proteins MotA and MotB, drive motor rotation, because one can obtain point mutations in these proteins that disrupt rotation but not flagellation. Null mutations, however, in fliM, fliN, or fliG also result in aflagellated cells, a phenotype that has been proposed to arise because these proteins are needed to complete the flagellar export apparatus (23).There is extensive structural information about each of the switch proteins and their arrangement in the flagellum (reviewed in references 23 and 29, with additional key references added below). There are 26 copies of FliG, 34 copies of FliM, and ∼136 copies of FliN, arranged in a circular structure at the base of each flagellum. FliM is positioned between FliG and FliN and interacts with both. FliM also binds CheY-P via sequences in the first 16 amino acids, and elsewhere (15), to play a key role in switching flagellar rotation direction. FliG, the switch protein closest to the cytoplasmic membrane, interacts with the stator protein MotA, the FliF membrane protein that forms the flagellar basal-body MS ring, and the membrane-bound respiratory protein fumarate reductase (11). FliG has the most direct role in creating flagellar rotation. FliN is the most cytoplasmic component of the switch, and its role is not fully understood. FliN may play a role in switching by possibly binding CheY-P directly (36) and an additional role in flagellar assembly, because it binds to the flagellar export protein FliH and localizes it, along with its interaction partners FliI and FliJ, to the flagellum (20, 28, 36). FliN contains significant sequence similarity to secretion proteins of type III secretion systems of Yersinia pestis and Shigella flexneri. The conserved domain comprises most of FliN and is called a SpoA or PFAM PF01052 domain. Other FliN homologs include YscL and Spa33 (25).The flagellar switch of another well-studied chemotactic microbe, B. subtilis, differs slightly in its protein makeup from that of E. coli. B. subtilis contains FliM and FliG, which function similarly to their E. coli counterparts, but instead of FliN it has a protein called FliY (6, 42). FliY of B. subtilis has two functional domains, one of which is homologous to E. coli FliN, while the other shares similarity with the B. subtilis chemotaxis protein CheC, which functions to dephosphorylate CheY-P. FliY is the most active known phosphatase of CheY-P in B. subtilis (40, 41).H. pylori contains homologs of many of the chemotaxis and flagellar genes found in other organisms (32, 48). Curiously, its genome encodes four predicted flagellar switch proteins, FliG, FliM, and both FliY and FliN, although FliY was not annotated in the original genome analysis. Previous work had determined that H. pylori strain SS1 lacking fliG was aflagellated (1), but the other switch proteins had not been analyzed. As noted above, FliN and FliY share a FliN domain and so could have functional redundancy. fliY and fliM appear to reside in an operon, suggesting that the two encoded proteins function together (see Fig. S1 in the supplemental material).Since having all four flagellar switch proteins in one microbe is unusual, we were curious as to whether all four serve “switch” functions. As noted above, fliM and fliG deletions typically result in an aflagellated phenotype in other organisms. Others had previously shown that fliG mutations have this phenotype in H. pylori (1), and we additionally show here that fliM null mutants are also almost completely aflagellate. In spite of a shared domain that might indicate functional redundancy, we show that fliN and fliY are each necessary for normal numbers of flagellated cells. Finally, we characterize a fliM point mutant that results in a lock-smooth swimming bias and demonstrate physical interaction between CheY-P and FliM, indicating that FliM responds to CheY signaling in H. pylori in a manner similar to that found in E. coli, S. Typhimurium, B. subtilis, and other studied organisms.     

Synthesis and Computational Exploration of Morpholine Bearing Halogenated Sulfonamides as Potential Tyrosinase Inhibitors

In the presented work, a new series of three different 4-((3,5-dichloro-2-[(2/4-halobenzyl)oxy]phenyl)sulfonyl)morpholines was synthesized and the structure of these compounds were corroborated by ¹H-NMR & ¹³C-NMR studies. The in vitro results established all the three compounds as potent tyrosinase inhibitors relative to the standard. The Kinetics mechanism plots established that compound 8 inhibited the enzyme non-competitively. The inhibition constants K_i calculated from Dixon plots for this compound was 0.0025 μM. Additionally, computational techniques were used to explore electronic structures of synthesized compounds. Fully optimized geometries were further docked with tyrosinase enzyme for inhibition studies. Reasonably good binding/interaction energies and intermolecular interactions were obtained. Finally, drug likeness was also predicted using the rule of five (RO5) and Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. It is anticipated that current experimental and computational investigations will evoke the scientific interest of the research community for the above-entitled compounds.     

Biochemical Characterization and Potential of Bacillus safensis Strain SCAL1 to Mitigate Heat Stress in Solanum lycopersicum L.

Journal of Plant Growth Regulation - Endophytic microbes promote plant growth through various biochemical mechanisms and assist plants in resuming their morpho-physiological traits under abiotic...