Drosophila homologue of Eps15 is essential for synaptic vesicle recycling

The mammalian protein Eps15 is phosphorylated by EGF receptor tyrosine kinase and has been shown to interact with several components of the endocytic machinery. We have identified a hypomorphic Eps15 mutant in Drosophila which shows reversible paralysis and an altered physiology at restrictive temperatures. In addition, the temperature-sensitive paralytic defect of shibire mutant is enhanced by this mutant. Eps15 is enriched in the larval neuromuscular junction in endocytic 'hot spots' in a pattern similar to Dynamin. Eps15 mutants show a decrease in the alpha-Adaptin levels at the larval neuromuscular junction synapse. Genetic and biochemical studies of interactions with components of the endocytic machinery suggest that Eps15 has an important role in synaptic vesicle recycling and regulates recruitment of alpha-Adaptin.     

Disruption of the kinin B1 receptor gene affects potentiating effect of captopril on BK-induced contraction in mice stomach fundus

A transgenic mouse model, deficient in kinin B₁ receptor (B₁^−/−) was used to evaluate the role of B₂ receptor in the smooth muscle stomach fundus. The results showed that the potency of bradykinin (BK) to induce contraction in the gastric tissue was maintained whereas the efficacy was markedly reduced. The angiotensin converting enzyme (ACE) inhibitor captopril potentiated BK-induced effect in wild type (WT) but not in B₁^−/− fundus. However, ACE activity detected by the convertion of Ang I to Ang II was inhibited by captopril in both types of gastric tissues. Taking into account the hypothesis that captopril and ACE bind to the B₂ receptor, we suggest that this complex was not formed in the stomach deficient in B₁ receptor. Therefore, our finding strongly support the hypothesis that in smooth muscles that constitutively express the kinin B₁ and B₂ receptors, an interaction between captopril and ACE, B₁ and B₂ receptors should occur forming a complex protein interaction for the potentiating effect of ACE on kinin receptors.     

Genetic and clonal diversity of the endemic ant-plant Humboldtia brunonis (Fabaceae) in the Western Ghats of India

Humboldtia brunonis (Fabaceae, Caesalpinioideae) is a dominant self-incompatible ant-plant or myrmecophyte, growing as an understorey tree in high-density patches. It is endemic to the biodiversity hotspot of the southern Western Ghats of India and, besides ants, harbours many endemic invertebrate taxa, such as bees that pollinate it as well as arboreal earthworms, within swollen hollow stem internodes called domatia. Using inter simple sequence repeat (ISSR) markers, three geographically separated populations were found to be multiclonal, characterized by high levels of clonal diversity. Values for the Simpson diversity index ranged between 0.764 and 0.964, and for Fager’s evenness index between 0.00 and 0.036 for neighbourhoods within populations. This myrmecophyte was found to combine sexual recruitment (66.7%) and clonal production (33.3%) as methods of reproduction. Moderate amounts of genetic diversity at the species level were observed, with 52.63% polymorphism, and moderate values of Shannon’s diversity index (0.1895) as well as of Nei’s gene diversity (0.1186). In each population, observed genotypic diversity was significantly lower than expected, indicating significant genetic structure. Neighbour-joining trees demonstrated that Agumbe, which is the most northern population examined and geographically twice as far away from the other two populations, grouped separately and with larger bootstrap support from a larger cluster consisting of the Sampaji and Solaikolli populations, which are closer to each other geographically. Some neighbourhoods within each population showed spatial genetic structure even at small spatial scales of <5 m. A combination of clonality and short-distance pollen movement by small pollinating bees (Braunsapis puangensis) coupled with primary ballistic seed dispersal, and possible secondary seed dispersal by rodents, may contribute to spatial genetic structure at such small scales. The clonality of H. brunonis may be a factor that contributes to its dominance in Western Ghat forests where it supports a rich diversity of invertebrate fauna.     

Social chemosignals from breastfeeding women increase sexual motivation

Human pheromones, a type of social chemosignal, modulate endocrine function by regulating the timing of ovulation. In animals, pheromones not only regulate ovulation but also female reproductive motivation and behavior. There is no extant evidence that humans produce social chemosignals that affect human sexual motivation or reproductive behavior as occurs in other mammals. Here, we demonstrate that natural compounds collected from lactating women and their breastfeeding infants increased the sexual motivation of other women, measured as sexual desire and fantasies. Moreover, the manifestation of increased sexual motivation was different in women with a regular sexual partner. Those with a partner experienced enhanced sexual desire, whereas those without one had more sexual fantasies. These results are consistent with previous pheromonal effects on endocrine function, and warrant further study of these social chemosignals as candidates for pheromonal processes, including their effects on other aspects of motivation and behavior.     

Survival of a strain of Bacillus megaterium carrying a lepidopteran-specific gene of Bacillus thuringiensis in the phyllospheres of various economically important plants

The colonizing ability of a transcipient strain of Bacillus megaterium carrying a lepidopteran-specific cryIA (a) gene of Bacillus thuringiensis in the phyllospheres of various economically important plants was studied. Similar experiments were also carried out using the parental B. thuringiensis var. kurstaki strain HD1 for a comparison. While the transcipient remained on the leaves of cotton and okra for more than 28 days, its survival in phyllospheres of mulberry, peanut, chickpea, tomato and rice was rather limited to about 3 – 5 days. The persistence of B. thuringiensis, on the other hand, was extremely short (i.e. less than 4 days) on all the crop plants tested.     

Unique biochemical and behavioral alterations in Drosophila shibire(ts1) mutants imply a conformational state affecting dynamin subcellular distribution and synaptic vesicle cycling

Dynamin is a GTPase protein that is essential for clathrin-mediated endocytosis of synaptic vesicle membranes. The Drosophila dynamin mutation shi(ts1) changes a single residue (G273D) at the boundary of the GTPase domain. In cell fractionation of homogenized fly heads without monovalent cations, all dynamin was in pellet fractions and was minimally susceptible to Triton-X extraction. Addition of Na(+) or K(+) can extract dynamin to the cytosolic (supernatant) fraction. The shi(ts1) mutation reduced the sensitivity of dynamin to salt extraction compared with other temperature-sensitive alleles or wild type. Sensitivity to salt extraction in shi(ts1) was enhanced by GTP and nonhydrolyzable GTP-gammaS. The shi(ts1) mutation may therefore induce a conformational change, involving the GTP binding site, that affects dynamin aggregation. Temperature-sensitive shibire mutations are known to arrest endocytosis at restrictive temperatures, with concomitant accumulation of presynaptic collared pits. Consistent with an effect upon dynamin aggregation, intact shi(ts1) flies recovered much more slowly from heat-induced paralysis than did other temperature-sensitive shibire mutants. Moreover, a genetic mutation that lowers GTP abundance (awd(msf15)), which reduces the paralytic temperature threshold of other temperature-sensitive shibire mutations that lie closer to consensus GTPase motifs, did not reduce the paralytic threshold of shi(ts1). Taken together, the results may link the GTPase domain to conformational shifts that influence aggregation in vitro and endocytosis in vivo, and provide an unexpected point of entry to link the biophysical properties of dynamin to physiological processes at synapses.     

Synthesis of esculentin-1 antibacterial peptide fragments on 1,4-butanediol dimethacrylate cross-linked polystyrene support

Peptide segments corresponding to antibacterial esculentin-1 (1–15), (33–44), (9–27), and their modified forms were synthesized on 1,4-butanediol dimethacrylate cross-linked polystyrene (PS-BDODMA) support. Hydroxymethyl and aminomethyl 2% PS-BDODMA supports were used for the synthesis. The HMPB linker was appended to the aminomethyl resin using HBTU in presence of HOBt and the first amino acid was incorporated using MSNT. The conventional Fmoc synthetic protocol was used for the synthesis of peptides. The peptides were cleaved from the support using TFA. The peptides were purified by HPLC, and characterized by amino acid analysis and MALDI TOF MS. The secondary structures of the peptides were revealed by CD measurements. The synthesis of these peptides illustrates the utility of the new support for the synthesis of long-chain bioactive peptides. The synthetic peptides were tested for antimicrobial activity against Escherichia coli Mos blue, E. coli 2, Bacillus brevis, B. megaterium, Pseudomonas HTL, and Vibrio mimicus. The antibacterial activity of the peptides was explained on the basis of the helicity and charged nature of the sequences.     

The Usefulness and Feasibility of Mobile Interface in Tuberculosis Notification (MITUN) Voice Based System for Notification of Tuberculosis by Private Medical Practitioners – A Pilot Project

Introduction

Tuberculosis (TB) is a notifiable disease and health care providers are required to notify every TB case to local authorities. We conducted a pilot study to determine the usefulness and feasibility of mobile interface in TB notification (MITUN) voice based system for notification of TB cases by private medical practitioners.

Methodology

The study was conducted during September 2013 to October 2014 in three zones of Chennai, an urban setting in South India. Private clinics wherein services are provided by single private medical practitioners were approached. The steps involved in MITUN included: Registration of the practitioners and notification of TB cases by them through voice interactions. Pre and post-intervention questionnaires were administered to collect information on TB notification practices and feasibility of MITUN after an implementation period of 6 months.

Results

A total of 266 private medical practitioners were approached for the study. Of them, 184 (69%) participated in the study; of whom 11 (6%) practitioners used MITUN for TB notification. Reasons for not using MITUN include lack of time, referral of patients to government facility, issues related to patient confidentiality and technical problems. Suggestions for making mobile phone based TB notification process user-friendly included reducing call duration, including only crucial questions and using missed call or SMS options.

Conclusion

The performance (feasibility and usefulness) of MITUN voice based system for TB notification in the present format was sub-optimal. Perceived problems, logistical and practical issues preclude scale–up of notification of TB by private practitioners.     

Recruitment of PLANT U-BOX13 and the PI4Kβ1/β2 Phosphatidylinositol-4 Kinases by the Small GTPase RabA4B Plays Important Roles during Salicylic Acid-Mediated Plant Defense Signaling in Arabidopsis

Protection against microbial pathogens involves the activation of cellular immune responses in eukaryotes, and this cellular immunity likely involves changes in subcellular membrane trafficking. In eukaryotes, members of the Rab GTPase family of small monomeric regulatory GTPases play prominent roles in the regulation of membrane trafficking. We previously showed that RabA4B is recruited to vesicles that emerge from trans-Golgi network (TGN) compartments and regulates polarized membrane trafficking in plant cells. As part of this regulation, RabA4B recruits the closely related phosphatidylinositol 4-kinase (PI4K) PI4Kβ1 and PI4Kβ2 lipid kinases. Here, we identify a second Arabidopsis thaliana RabA4B-interacting protein, PLANT U-BOX13 (PUB13), which has recently been identified to play important roles in salicylic acid (SA)-mediated defense signaling. We show that PUB13 interacts with RabA4B through N-terminal domains and with phosphatidylinositol 4-phosphate (PI-4P) through a C-terminal armadillo domain. Furthermore, we demonstrate that a functional fluorescent PUB13 fusion protein (YFP-PUB13) localizes to TGN and Golgi compartments and that PUB13, PI4Kβ1, and PI4Kβ2 are negative regulators of SA-mediated induction of pathogenesis-related gene expression. Taken together, these results highlight a role for RabA4B and PI-4P in SA-dependent defense responses.