T4-like Escherichia coli phages from the environment carry blaCTX-M.

The resistance determinant blaCTX-M has many variants and has been the most commonly reported gene in clinical isolates of extended spectrum beta-lactamase producing Escherichia coli. Phages have been speculated as potential reservoirs of resistance genes and efficient vehicles for horizontal gene transfer. The objective of the study was to determine the prevalence and characterize bacteriophages that harbour the resistance determinant blaCTX-M . Escherichia coli specific bacteriophages were isolated from 15 samples including soil and water across Mangaluru, India using bacterial hosts that were sensitive to ß-lactams. Phenotypic and genotypic characterization based on plaque morphology, host range, restriction fragment length polymorphism (RFLP), presence of blaCTX-M and electron microscopy was performed. Of 36 phages isolated, seven were positive for Group 1 of blaCTX-M . Based on host range and RFLP pattern, the seven phages were classified into four distinct groups, each harbouring a variant of blaCTX-M . Five phages were T4-like Myoviridae by electron microscopy which was further confirmed by polymerase chain reaction (PCR) for T4 specific gp14. Generalized transduction of the CTX-M gene from these phages was also observed. The high prevalence (20%) of this gene blaCTX-M in the phage pool confirms the significant role of Myoviridae members, specifically T4-like phages in the dissemination of this resistance gene. SIGNIFICANCE AND IMPACT OF THE STUDY: The CTX-M gene that confers resistance to Beta-lactam class of drugs is widespread and diverse. Understanding mechanisms of antimicrobial resistance transfer is a key to devise methods for controlling it. Few studies indicate that bacteriophages are involved in the transfer of this gene but the type of phages involved and the degree of involvement remains to be explored. Our work has been able to identify the class of phages and the magnitude of involvement in the dissemination of this gene.

Oral application of a periodontal pathogen impacts SerpinE1 expression and pancreatic islet architecture in prediabetes.

BACKGROUND AND OBJECTIVES: Epidemiological studies suggest a close association between periodontitis and prediabetes/insulin resistance (IR) but whether periodontitis causes prediabetes in humans is not known. Using various animal models, we have recently established that periodontitis can be an initiator of prediabetes, which is characterized by glucose intolerance, hyperinsulinemia and IR. In addition, our in vitro studies indicated that Porphyromonas gingivalis (Pg) induced insulin secretion in MIN6 ß cells and this induction was in part SerpinE1 (plasminogen activator inhibitor 1, PAI1) dependent. However, the mechanism(s) by which periodontitis induces prediabetes is not known. As α and ß cells in pancreatic islets are the major modulators of glucose levels, we investigated whether experimental periodontitis by oral application of a periodontal pathogen caused molecular and/or cellular alterations in pancreatic islets and whether SerpinE1 was involved in this process. MATERIAL AND METHODS: We induced periodontitis in C57BL/6 mice by oral application of a periodontal pathogen, Pg, and determined changes that occurred in islets following 22 weeks of Pg application. Pancreatic islet architecture was determined by 2-D and 3-D immunofluorescence microscopy and SerpinE1 and its target, urokinase plasminogen activator (uPA), as well as insulin, glucagon and Pg/gingipain in islets were detected by immunofluorescence. The presence of apoptotic islet cells was determined by both histochemical and immunofluorescence TUNEL assays. To investigate further the direct effect of Pg on apoptosis and the involvement of SerpinE1 in this process, we used SerpinE1 knockdown and scrambled control clones of the MIN6 pancreatic ß-cell line. RESULTS: Pg/gingipain was detected in both the periodontium and pancreas in the experimental group. Islets from animals that were administered Pg orally (experimental group) developed significant changes in islet architecture, upregulation of SerpinE1, and increased ß-cell apoptosis compared with the control group. We also observed that exposure of MIN6 cells to Pg in vitro resulted in apoptosis. However, apoptosis was significantly reduced when SerpinE1 expression by MIN6 cells was knocked down. CONCLUSION: Oral application of the periodontal pathogen Pg to C57BL/6 mice induces periodontitis, translocation of Pg/gingipain to the pancreas and results in complex alterations in pancreatic islet morphology. SerpinE1 appears to be involved in this process.

Mapping of Post-translational Modifications of Transition Proteins, TP1 and TP2, and Identification of Protein Arginine Methyltransferase 4 and Lysine Methyltransferase 7 as Methyltransferase for TP2.

In a unique global chromatin remodeling process during mammalian spermiogenesis, 90% of the nucleosomal histones are replaced by testis-specific transition proteins, TP1, TP2, and TP4. These proteins are further substituted by sperm-specific protamines, P1 and P2, to form a highly condensed sperm chromatin. In spermatozoa, a small proportion of chromatin, which ranges from 1 to 10% in mammals, retains the nucleosomal architecture and is implicated to play a role in transgenerational inheritance. However, there is still no mechanistic understanding of the interaction of chromatin machinery with histones and transition proteins, which facilitate this selective histone replacement from chromatin. Here, we report the identification of 16 and 19 novel post-translational modifications on rat endogenous transition proteins, TP1 and TP2, respectively, by mass spectrometry. By in vitro assays and mutational analysis, we demonstrate that protein arginine methyltransferase PRMT4 (CARM1) methylates TP2 at Arg(71), Arg(75), and Arg(92) residues, and lysine methyltransferase KMT7 (Set9) methylates TP2 at Lys(88) and Lys(91) residues. Further studies with modification-specific antibodies that recognize TP2K88me1 and TP2R92me1 modifications showed that they appear in elongating to condensing spermatids and predominantly associated with the chromatin-bound TP2. This work establishes the repertoire of post-translational modifications that occur on TP1 and TP2, which may play a significant role in various chromatin-templated events during spermiogenesis and in the establishment of the sperm epigenome.

Structural Transitions in Densifying Networks.

We introduce a minimal generative model for densifying networks in which a new node attaches to a randomly selected target node and also to each of its neighbors with probability p. The networks that emerge from this copying mechanism are sparse for p<1/2 and dense (average degree increasing with number of nodes N) for p≥1/2. The behavior in the dense regime is especially rich; for example, individual network realizations that are built by copying are disparate and not self-averaging. Further, there is an infinite sequence of structural anomalies at p=2/3, 3/4, 4/5, etc., where the N dependences of the number of triangles (3-cliques), 4-cliques, undergo phase transitions. When linking to second neighbors of the target can occur, the probability that the resulting graph is complete-all nodes are connected-is nonzero as N→∞.

A rare case report of meningoencephalitis caused by Streptococcus porcinus.

Acute pyogenic meningitis is a medical emergency. Bacteria are the major causative agents of pyogenic meningitis with Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis being the most common. Here, we describe a case of bacterial meningoencephalitis caused by Streptococcus porcinus. To our knowledge this is the first case described in literature. The patient was treated with ceftriaxone and supportive treatment.

Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae) in Eastern Arabian Sea.

Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea (South-West coast of India). For this, the Dorsal Mantle Length (DML) and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modal-progression analysis using the Bhattacharya's method for the estimation of growth. The estimated parameters Linfinity and K in von Bertalanffy Growth Function (VBGF) were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort) which supports the major fishery, was composed of medium-sized, fast growing individuals, whereas the second cohort (pre-monsoon cohort), comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3 years for males and 2.1 years for females. Negative allometric growth in weight (W) with length (L) was observed for males (W=0.33069.L2.5389) and females (W=0.32542.L26057). The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in comparison with 0.03-0.85kg/h in December-April. Seasonal catch rates indicated a migratory life cycle ofS. pharaonis between offshore and inshore coastal zones.

Awareness and preferences about suicide crisis support service options among college students in India: A cross sectional study.

BACKGROUND: Our objective was to explore the awareness about suicide support services and preferred service options during a suicide crisis among college going young adults. METHODS: Between September 2016 and February 2017, we invited students from colleges affiliated to three major universities in a coastal district of South India to participate in a cross-sectional survey. RESULTS: A total of 1890 usable responses were obtained. Most participants (n = 1633, 86.4%) were unaware of any suicide crisis support options. Most commonly listed options were support from family members, peer groups, counselling and psychiatric consultation. These were also endorsed as most preferred support options. CONCLUSION: There is a low level of awareness about suicide support services among young Indian adults. There is a need for coordinated efforts to raise awareness and promote uptake of suicide support services in this group.

Nature of optical excitations and bandgap of RexMo1-xS2alloy at nanoscale probed from high resolution low loss electron energy loss spectroscopy.

The two-dimensional (2D) transitional metal dichalcogenides (TMDS) have become an intensive research topic recently. The alloys of these TMDs have offered continuous tunability of the bandstructure and carrier concentration, providing a new opportunity for various device applications. Here the rich variations in optical excitations in RexMo1-xS2alloy at the nanoscale region are shown. The alloy bandgap and charge response are probed by low-loss high-resolution transmission electron energy loss spectroscopy (HR-EELS). Concurrent density functional theory calculations revealed many electronic structures from n-type semiconductors to metallic and p-type semiconducting nature with band bowing effect. The alloying-induced Peierls distortion leads to a change in crystal symmetry and decreased interlayer coupling. These alloys undergo indirect to direct bandgap transition with the function of Re concentration. These unique correlated structural and electronic properties of these 2D alloys can be potentially applicable for various electronic and optoelectronic devices.

Platelet function in patients with major depression.

Depression, ischaemic heart disease and cerebrovascular disease are important causes of morbidity and are among the leading contributors to global health burden. These conditions often occur in the same patient, resulting in considerably greater effect on health than combinations of chronic diseases without depression. The frequent occurrence of these conditions in the same patient raises the possibility of a common genetic predisposition, similar risk factors or a pathophysiological link. Serotoninergic and adrenergic signalling play important roles in causing major depression and also in platelet activation and aggregation, which underlies vascular disease. This review discusses the potential pathophysiological link between major depression and conditions in which platelet activation plays an important role and also provides evidence linking the use of the most commonly used antidepressant drugs (i.e. the selective serotonin re-uptake inhibitors) to increased risk of bleeding.

A novel anticancer agent ARC antagonizes HIV-1 and HCV.

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) pose major public health concerns worldwide. HCV is clearly associated with the occurrence of hepatocellular carcinoma, and recently HIV infection has also been linked to the development of a multitude of cancers. Previously, we identified a novel nucleoside analog transcriptional inhibitor ARC (4-amino-6-hydrazino-7-beta-D-ribofuranosyl-7H-pyrrolo[2,3-d]-pyrimidine-5-carboxamide) that exhibited proapoptotic and antiangiogenic properties in vitro. Here, we evaluated the effect of ARC on HIV-1 transcription and HCV replication. Using reporter assays, we found that ARC inhibited HIV-1 Tat-based transactivation in different cell systems. Also, using hepatoma cells that harbor subgenomic and full-length replicons of HCV, we found that ARC inhibited HCV replication. Together, our data indicate that ARC could be a promising candidate for the development of antiviral therapeutics against HIV and HCV.

Optimally frugal foraging.

We introduce the frugal foraging model in which a forager performs a discrete-time random walk on a lattice in which each site initially contains S food units. The forager metabolizes one unit of food at each step and starves to death when it last ate S steps in the past. Whenever the forager eats, it consumes all food at its current site and this site remains empty forever (no food replenishment). The crucial property of the forager is that it is frugal and eats only when encountering food within at most k steps of starvation. We compute the average lifetime analytically as a function of the frugality threshold and show that there exists an optimal strategy, namely, an optimal frugality threshold k^{*} that maximizes the forager lifetime.

Psychological distress among college students of coastal district of Karnataka: A community-based cross-sectional survey.

BACKGROUND: Common Mental Disorders (CMDs) are frequent among adolescents and early adults. National Mental Health Survey of India 2015-2016 shows alarming results, especially for depression. This study explored the prevalence of psychological distress among college students. Additionally, the relationship between gender, living arrangement with psychological distress in various educational streams were explored. MATERIALS AND METHODS: Through a cross-sectional community-based survey a total of 4839 college going students of various educational streams in Mangalore, Karnataka were assessed for psychological distress with Self-Reporting Questionnaire (SRQ-20). RESULTS: Participants had median age of 19 (range = 9) years and the majority (59.5%) were females. The median SRQ score was 4 (range 20) and about 28.5% of students were found to be psychologically stressed. The suicidal ideation was reported by 13.6% of the students. Engineering and Arts/science/commerce students had significantly higher psychological distress scores as compared to health and allied sciences (k = 47.7; p < 0.001) and those who were staying with families (U = 2,687,648.5; p = 0.004) reported higher levels of psychological distress in comparison to those who were staying away from their families. CONCLUSION: Prevalence of psychological distress was high among students, especially non-medical students, students who were staying with their families, and those who were younger in age. A significant proportion of students had suicidal ideation, which needs early mental health interventions at the college level.

Does greed help a forager survive?

We investigate the role of greed on the lifetime of a random-walking forager on an initially resource-rich lattice. Whenever the forager lands on a food-containing site, all the food there is eaten and the forager can hop S more steps without food before starving. Upon reaching an empty site, the forager comes one time unit closer to starvation. The forager is also greedy-given a choice to move to an empty or to a food-containing site in its local neighborhood, the forager moves preferentially toward food. Surprisingly, the forager lifetime varies nonmonotonically with greed, with different senses of the nonmonotonicity in one and two dimensions. Also unexpectedly, the forager lifetime in one dimension has a huge peak for very negative greed where the forager is food averse.

Densification and structural transitions in networks that grow by node copying.

We introduce a growing network model, the copying model, in which a new node attaches to a randomly selected target node and, in addition, independently to each of the neighbors of the target with copying probability p. When p<1/2, this algorithm generates sparse networks, in which the average node degree is finite. A power-law degree distribution also arises, with a nonuniversal exponent whose value is determined by a transcendental equation in p. In the sparse regime, the network is "normal," e.g., the relative fluctuations in the number of links are asymptotically negligible. For p≥1/2, the emergent networks are dense (the average degree increases with the number of nodes N), and they exhibit intriguing structural behaviors. In particular, the N dependence of the number of m cliques (complete subgraphs of m nodes) undergoes m-1 transitions from normal to progressively more anomalous behavior at an m-dependent critical values of p. Different realizations of the network, which start from the same initial state, exhibit macroscopic fluctuations in the thermodynamic limit: absence of self-averaging. When linking to second neighbors of the target node can occur, the number of links asymptotically grows as N^{2} as N→∞, so that the network is effectively complete as N→∞.

Differences in mutant p53 protein stability and functional activity in teniposide-sensitive and -resistant human leukemic CEM cells.

We examined p53 protein stability and DNA damage-induced p53-dependent responses in a human leukemic CEM cell line and two teniposide-resistant sublines, CEM/VM-1 and CEM/VM-1-5 ( approximately 40 and 400-fold resistant to teniposide, respectively). Although all cell lines contain the same p53 mutations at codons 175 (Arg-->His) and 248 (Arg-->Gln), the constitutive levels of p53 were progressively increased with the resistance of the cells to teniposide. By pulse-chase experiments, we found that the half-lives of mutant p53 protein were approximately 12, 17, and >30 h in CEM, CEM/VM-1, and CEM/VM-1-5 cells, respectively. The prolonged half-lives of p53 in these cells is consistent with the fact that the protein harbors the indicated mutations. Of note, however, is the fact that the increased p53 protein half-lives in the two drug-resistant cell lines corresponds to a proportional decrease in MDM2 protein levels but an increase in p53-MDM2 binding interactions. This suggests that MDM2-mediated p53 degradation may be altered in our leukemic cell lines. The DNA damage-induced p53 response is fully functional in the drug-sensitive CEM cells containing a mutant p53, but this pathway is attenuated in the drug-resistant cells. Specifically, while the mutant p53 was phosphorylated at serine-15 in response to ionizing radiation in all these cell lines, mutant p53 induction in response to teniposide or ionizing radiation and induction of the p53-target genes, p21 and GADD45 only occurred in the drug-sensitive CEM cells. As assessed by MTT cytotoxicity assay, CEM cells were also significantly more sensitive to ionizing radiation, compared to the drug-resistant cell lines, and this correlated with p53 induction. Collectively, these results suggest that changes in constitutive mutant p53 protein levels, p53-MDM2 binding interactions, and altered regulation of the DNA damage-inducible p53-dependent pathway may play a role in drug- and radiation-responsiveness in these cells.

Characterization of lipopolysaccharides from four Pasteurella haemolytica serotype strains: evidence for presence of sialic acid in serotypes 1 and 5.

Highly purified lipopolysaccharides (LPS) obtained from four strains of Pasteurella haemolytica representative of four different serotypes were studied to ascertain their overall structural elements and sugar and fatty acid compositions. SDS-PAGE analysis revealed that each LPS was of the smooth-type although they differed in migration patterns. Somewhat unusual features of these LPS included the presence of: (a) rhamnose in the core oligosaccharides of serotypes 2 and 3; and (b) sialic acid in the LPS of serotypes 1 and 5. The fatty acids, myristic, hydroxymyristic and palmitic occur in essentially equivalent amounts in each of these LPS. In addition, stearic acid was present in small amounts of serotypes 1 and 5.

Temperature-dependent incorporation of 4-amino-L-arabinose in lipid A of distinct gram-negative bacteria.

The presence and the relative amount of 4-amino-L-arabinose in lipopolysaccharides of members of the Enterobacteriaceae family and in a single strain of Chromobacterium violaceum has been studied with regard to growth-temperature dependent variations. Changes in the presence and the amount of 4-amino-L-arabinose (4-AA) were observed in almost all cases, but the variations observed were not consistent among different species. While Salmonella minnesota and Proteus mirabilis showed higher levels of incorporation at higher temperatures, the S- and R-forms of Yersinia enterocolitica showed the opposite effect, i.e. only marginal incorporation by growth at 10 degrees C. Chromobacterium violaceum, however, showed no significant alteration in the 4-amino-L-arabinose content when growth either at 14 or at 37 degrees C. DOC-PAGE pattern of isolated lipopolysaccharides showed characteristic profiles indicating that the O-chain-synthesis of distinct Enterobacteriaceae is also differently influenced by changes in growth temperature.

An Escherichia coli plasmid-based, mutational system in which supF mutants are selectable: insertion elements dominate the spontaneous spectra.

A new system is described to determine the mutational spectra of mutagens and carcinogens in Escherichia coli; data on a limited number (142) of spontaneous mutants is presented. The mutational assay employs a method to select (rather than screen) for mutations in a supF target gene carried on a plasmid. The E. coli host cells (ES87) are lacI- (am26), and carry the lacZ delta M15 marker for alpha-complementation in beta-galactosidase. When these cells also carry a plasmid, such as pUB3, which contains a wild-type copy of supF and lacZ-alpha, the lactose operon is repressed (off). Furthermore, supF suppression of lacIam26 results in a lactose repressor that has an uninducible, lacIS genotype, which makes the cells unable to grow on lactose minimal plates. In contrast, spontaneous or mutagen-induced supF- mutations in pUB3 prevent suppression of lacIam26 and result in constitutive expression of the lactose operon, which permits growth on lactose minimal plates. The spontaneous mutation frequency in the supF gene is approximately 0.7 and approximately 1.0 x 10(-6) without and with SOS induction, respectively. Spontaneous mutations are dominated by large insertions (67% in SOS-uninduced and 56% in SOS-induced cells), and their frequency of appearance is largely unaffected by SOS induction. These are identified by DNA sequencing to be Insertion Elements; IS1 dominates, but IS4, IS5, gamma-delta and IS10 are also obtained. Large deletions also contribute significantly (19% and 15% for -SOS and +SOS, respectively), where a specific deletion between a 10 base pair direct repeat dominates; the frequency of appearance of these mutations also appears to be unaffected by SOS induction. In contrast, SOS induction increases base pairing mutations (13% and 27% for -SOS and +SOS, respectively). The ES87/pUB3 system has many advantages for determining mutational spectra, including the fact that mutant isolation is fast and simple, and the determination of mutational changes is rapid because of the small size of supF.

Establishment and characterization of a diploid cell line from the tick, Dermacentor parumapertus Neumann (Acarina: Ixodidae).

Establishment of a continuous cell line (RML-14) from embryonic tissues of the tick Dermacentor parumapertus Neumann is reported. The culture medium employed consisted of a combination (2:1) of Eagle's and L-15 (Leibovitz) media supplemented with 20% fetal bovine serum, 10% tryptose phosphate broth, and 0.1% bovine plasma albumin. At the 8th passage, 99% of dividing cells had the female chromosome complement, among which more than 70% had a diploid chromosome number of 22. At the 13th passage, cell population showed approximately a 3-fold increase during the first 8 days of culture. As of December 1976, had been subcultured 40 times.