Interpain A, a cysteine proteinase from Prevotella intermedia, inhibits complement by degrading complement factor C3

Periodontitis is an inflammatory disease of the supporting structures of the teeth caused by, among other pathogens, Prevotella intermedia. Many strains of P. intermedia are resistant to killing by the human complement system, which is present at up to 70% of serum concentration in gingival crevicular fluid. Incubation of human serum with recombinant cysteine protease of P. intermedia (interpain A) resulted in a drastic decrease in bactericidal activity of the serum. Furthermore, a clinical strain 59 expressing interpain A was more serum-resistant than another clinical strain 57, which did not express interpain A, as determined by Western blotting. Moreover, in the presence of the cysteine protease inhibitor E64, the killing of strain 59 by human serum was enhanced. Importantly, we found that the majority of P. intermedia strains isolated from chronic and aggressive periodontitis carry and express the interpain A gene. The protective effect of interpain A against serum bactericidal activity was found to be attributable to its ability to inhibit all three complement pathways through the efficient degradation of the alpha-chain of C3 -- the major complement factor common to all three pathways. P. intermedia has been known to co-aggregate with P. gingivalis, which produce gingipains to efficiently degrade complement factors. Here, interpain A was found to have a synergistic effect with gingipains on complement degradation. In addition, interpain A was able to activate the C1 complex in serum, causing deposition of C1q on inert and bacterial surfaces, which may be important at initial stages of infection when local inflammatory reaction may be beneficial for a pathogen. Taken together, the newly characterized interpain A proteinase appears to be an important virulence factor of P. intermedia.

Small-molecule inhibitors of the Rce1p CaaX protease

The Rce1p protease is required for the maturation of the Ras GTPase and certain other isoprenylated proteins and is considered a chemotherapeutic target. To identify new small-molecule inhibitors of Rce1p, the authors screened the National Cancer Institute Diversity Set compound library using in vitro assays to monitor the proteolytic processing of peptides derived from Ras and the yeast a-factor mating pheromone. Of 46 inhibitors initially identified with a Ras-based assay, only 9 were effective in the pheromone-based assay. The IC(50) values of these 9 compounds were in the low micromolar range for both yeast (6-35 microM) and human Rce1p (0.4-46 microM). Four compounds were somewhat Rce1p selective in that they partially inhibited the Ste24p protease and did not inhibit Ste14p isoprenylcysteine carboxyl methyltransferase, 2 enzymes also involved in the maturation of isoprenylated proteins. The remaining 5 compounds inhibited all 3 enzymes. The 2 most Rce1p-selective agents were ineffective trypsin inhibitors, further supporting the specificity of these agents for Rce1p. The 5 least specific compounds formed colloidal aggregates, a proposed common feature of promiscuous inhibitors. Interestingly, the most specific Rce1p inhibitor also formed a colloidal aggregate. In vivo studies revealed that treatment of wild-type yeast with 1 compound induced a Ras2p delocalization phenotype that mimics observed effects in rce1 ste24 null yeast. The 9 compounds identified in this study represent new tools for understanding the enzymology of postisoprenylation-modifying enzymes and provide new insight for the future development of Rce1p inhibitors.

A new autocatalytic activation mechanism for cysteine proteases revealed by Prevotella intermedia interpain A

Prevotella intermedia is a major periodontopathogen contributing to human gingivitis and periodontitis. Such pathogens release proteases as virulence factors that cause deterrence of host defenses and tissue destruction. A new cysteine protease from the cysteine-histidine-dyad class, interpain A, was studied in its zymogenic and self-processed mature forms. The latter consists of a bivalved moiety made up by two subdomains. In the structure of a catalytic cysteine-to-alanine zymogen variant, the right subdomain interacts with an unusual prodomain, thus contributing to latency. Unlike the catalytic cysteine residue, already in its competent conformation in the zymogen, the catalytic histidine is swung out from its active conformation and trapped in a cage shaped by a backing helix, a zymogenic hairpin, and a latency flap in the zymogen. Dramatic rearrangement of up to 20A of these elements triggered by a tryptophan switch occurs during activation and accounts for a new activation mechanism for proteolytic enzymes. These findings can be extrapolated to related potentially pathogenic cysteine proteases such as Streprococcus pyogenes SpeB and Porphyromonas gingivalis periodontain.

In Vitro Propagation of Carrot (Daucus Carota) L

In vitro method for rapid propagation of Daucus carota L. was developed. Root, stem, leaf and nodal explants were cultured on MS medium supplemented with different concentration and combinations of hormones. Multiple shoot were induced from the nodal explant of D. carota by culturing them in MS medium supplemented with 0.5 mg/l of 6-benzylaminopurine (BAP). Differentiation of shoot initiated after one week of culture, and after eight weeks of primary culture, an average of six plantlets were developed from a single shoot. The nodal explant also induced same number of multiple shoot in MS medium supplemented with 2 mg/l of BAP and 1 mg/l of α-nephthalene acetic acid (NAA). The shoots when sub-cultured in the medium supplemented with 1 mg/l NAA produced roots after five weeks of sub-culture. Root and leaf explants induced roots and callus when cultured on MS medium with NAA at the rate of 1 mg/l and 2 mg/ l. Similarly, stem explants also induced roots and callus in the same concentration of hormones whereas few multiple shoot were induced when cultured on MS supplemented with 2 mg/l of BAP and 1 mg/l of NAA. This result suggests that this methodology can be applied for the rapid and mass propagation of this species. Key words: In vitro; Propagation; MS medium; Explant; Culture. DOI: 10.3126/sw.v5i5.2656 Scientific World, Vol. 5, No. 5, July 2007 51-53

Chemical inhibition of CaaX protease activity disrupts yeast Ras localization

Proteins possessing a C-terminal CaaX motif, such as the Ras GTPases, undergo extensive post-translational modification that includes attachment of an isoprenoid lipid, proteolytic processing and carboxylmethylation. Inhibition of the enzymes involved in these processes is considered a cancer-therapeutic strategy. We previously identified nine in vitro inhibitors of the yeast CaaX protease Rce1p in a chemical library screen (Manandhar et al., 2007). Here, we demonstrate that these agents disrupt the normal plasma membrane distribution of yeast GFP-Ras reporters in a manner that pharmacologically phenocopies effects observed upon genetic loss of CaaX protease function. Consistent with Rce1p being the in vivo target of the inhibitors, we observe that compound-induced delocalization is suppressed by increasing the gene dosage of RCE1. Moreover, we observe that Rce1p biochemical activity associated with inhibitor-treated cells is inversely correlated with compound dose. Genetic loss of CaaX proteolysis results in mistargeting of GFP-Ras2p to subcellular foci that are positive for the endoplasmic reticulum marker Sec63p. Pharmacological inhibition of CaaX protease activity also delocalizes GFP-Ras2p to foci, but these foci are not as strongly positive for Sec63p. Lastly, we demonstrate that heterologously expressed human Rce1p can mediate proper targeting of yeast Ras and that its activity can also be perturbed by some of the above inhibitors. Together, these results indicate that disrupting the proteolytic modification of Ras GTPases impacts their in vivo trafficking.

Seroprevalence of Japanese encephalitis virus and risk factors associated with seropositivity in pigs in four mountain districts in Nepal

Japanese encephalitis was recently reported from individuals in the mountain districts of Nepal without travel history to Japanese encephalitis virus (JEV) endemic areas. We performed a cross-sectional study to estimate the seroprevalence of JEV in pigs and subsequently conducted a survey of farmers to identify risk factors associated with seropositivity. In July and August, 2010, 454 pig serum samples were collected and tested by competitive ELISA. Data from a 35-question survey of 109 pig owners were analysed using multivariate logistic regression. Seventy-six (16.7, 95% CI 13.6-20.4) pigs tested positive for anti-JEV antibodies, none of which had been vaccinated against JEV or sourced from JEV endemic areas. Risk factors associated with JEV seropositivity were 'summer abortion', 'wells as a water source', 'urban location', 'reported presence of mosquitoes' and 'lower elevation'. Our results suggest that JEV is likely circulating in the mountain districts of Nepal, and that locally acquired JEV should be considered a risk for residents and travellers in these areas.

Photoaffinity labeling of Ras converting enzyme using peptide substrates that incorporate benzoylphenylalanine (Bpa) residues: improved labeling and structural implications

Rce1p catalyzes the proteolytic trimming of C-terminal tripeptides from isoprenylated proteins containing CAAX-box sequences. Because Rce1p processing is a necessary component in the Ras pathway of oncogenic signal transduction, Rce1p holds promise as a potential target for therapeutic intervention. However, its mechanism of proteolysis and active site have yet to be defined. Here, we describe synthetic peptide analogues that mimic the natural lipidated Rce1p substrate and incorporate photolabile groups for photoaffinity-labeling applications. These photoactive peptides are designed to crosslink to residues in or near the Rce1p active site. By incorporating the photoactive group via p-benzoyl-l-phenylalanine (Bpa) residues directly into the peptide substrate sequence, the labeling efficiency was substantially increased relative to a previously-synthesized compound. Incorporation of biotin on the N-terminus of the peptides permitted photolabeled Rce1p to be isolated via streptavidin affinity capture. Our findings further suggest that residues outside the CAAX-box sequence are in contact with Rce1p, which has implications for future inhibitor design.

Cell-permeable, small-molecule activators of the insulin-degrading enzyme

The insulin-degrading enzyme (IDE) cleaves numerous small peptides, including biologically active hormones and disease-related peptides. The propensity of IDE to degrade neurotoxic Aβ peptides marks IDE as a potential therapeutic target for Alzheimer disease. Using a synthetic reporter based on the yeast a-factor mating pheromone precursor, which is cleaved by multiple IDE orthologs, we identified seven small molecules that stimulate rat IDE activity in vitro. Half-maximal activation of IDE by the compounds is observed in vitro in the range of 43 to 198 µM. All compounds decrease the K(m) of IDE. Four compounds activate IDE in the presence of the competing substrate insulin, which disproportionately inhibits IDE activity. Two compounds stimulate rat IDE activity in a cell-based assay, indicating that they are cell permeable. The compounds demonstrate specificity for rat IDE since they do not enhance the activities of IDE orthologs, including human IDE, and they appear specific for a-factor-based reporters since they do not enhance rat IDE-mediated cleavage of Aβ-based reporters. Our results suggest that IDE activators function in the context of specific enzyme-substrate pairs, indicating that the choice of substrate must be considered in addition to target validation in IDE activator screens.

Subsurface synthesis and characterization of Ag nanoparticles embedded in MgO

Metal nanoparticles exhibit a localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the surrounding dielectric medium. The coupling between the electromagnetic radiation and the localized surface plasmon in metallic nanoparticles results in a sizable enhancement of the incident fields, making them possible candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix can provide prime locations for LSPR spectroscopy and sensing. We report the synthesis and characterization of a plasmonic substrate consisting of Ag nanoparticles partially buried in MgO. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag(+) ions followed by annealing at 1000 °C for 10 and 30 h. A detailed optical and structural characterization was carried out to understand the evolution of the Ag nanoparticle and size distribution inside the MgO matrix. Micro x-ray diffraction (Micro-XRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to a faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes, as visualized from aberration-corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface by employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles.

DESIGN OF A SURVEILLANCE SYSTEM FOR PREGNANCY AND ITS OUTCOMES IN RURAL NEPAL

IntroductionCommunity trials in low-income countries require monitoring and evaluation systems.The requirements of a community surveillance system include coherent design, training,field supervision and reporting, as well as the need for a robust and flexible database.Materials and methodsThis paper describes a surveillance system for identification of pregnancy and itsoutcomes in a rural area of Nepal. Mother Infant Research Activities (MIRA), incollaboration with the Institute of Child Health, London, are presently conducting astudy on the impact of a community-based participatory intervention to improveessential newborn care (ENC) in rural Nepal. The study is a cluster randomisedcontrolled trial involving 12 pairs of Village Development Committees (VDCs) inMakwanpur District. The surveillance system covers approximately 28 000 householdsand 28 000 married women of reproductive age. It was designed to identify pregnancy,its outcome for mother and infant, and activities such as antenatal care and problem-related health care seeking behaviour.DiscussionThe paper describes the processes of mapping and enumeration, pregnancyidentification, conduct of interviews, quality control and data management.Key Words: data quality, database, rural Nepal.

Yeast ENV9 encodes a conserved lipid droplet (LD) short-chain dehydrogenase involved in LD morphology

Lipid droplets (LDs) have emerged as dynamic and interactive organelles with important roles in lipid metabolism and membrane biogenesis. Here, we report that Saccharomyces cerevisiae Env9 is a novel conserved oxidoreductase involved in LD morphology. Microscopic and biochemical studies confirm localization of tagged Env9 to LDs and implicate its C-terminal hydrophobic domain (aa241-265) in its membrane association and stability. Confocal studies reveal a role for Env9 in LD morphology. Env9 positively affects both formation of large LDs upon overexpression and LD proliferation under poor carbon source. In silico bioinformatic and modeling approaches establish that ENV9 is a widely conserved member of the short-chain dehydrogenase (SDR) superfamily. Bayesian phylogenetic studies strongly support ENV9 as an ortholog of human SDR retinol dehydrogenase 12 (RDH12). Dehydrogenase activity of Env9 was confirmed by in vitro oxidoreductase assays. RDH12 mutations have been linked to Leber Congenital Amaurosis. Similar site-directed point mutations in the predicted Env9 oxidoreductase active site (N146L) or cofactor-binding site (G23-24A) abolished its reductase activity in vitro, consistent with those reported in other retinol dehydrogenases. The same residues were essential for affecting LD size and number in vivo. Taken together, our results implicate oxidoreductase activity of Env9 in its cellular role in LD morphology.

Hygromycin B hypersensitive (hhy) mutants implicate an intact trans-Golgi and late endosome interface in efficient Tor1 vacuolar localization and TORC1 function

Saccharomyces cerevisiae vacuoles are functionally analogous to mammalian lysosomes. Both also serve as physical platforms for Tor Complex 1 (TORC1) signal transduction, the master regulator of cellular growth and proliferation. Hygromycin B is a eukaryotic translation inhibitor. We recently reported on hygromycin B hypersensitive (hhy) mutants that fail to grow at subtranslation inhibitory concentrations of the drug and exhibit vacuolar defects (Banuelos et al. in Curr Genet 56:121-137, 2010). Here, we show that hhy phenotype is not due to increased sensitivity to translation inhibition and establish a super HHY (s-HHY) subgroup of genes comprised of ARF1, CHC1, DRS2, SAC1, VPS1, VPS34, VPS45, VPS52, and VPS54 that function exclusively or inclusively at trans-Golgi and late endosome interface. Live cell imaging of s-hhy mutants revealed that hygromycin B treatment disrupts vacuolar morphology and the localization of late endosome marker Pep12, but not that of late endosome-independent vacuolar SNARE Vam3. This, along with normal post-late endosome trafficking of the vital dye FM4-64, establishes that severe hypersensitivity to hygromycin B correlates specifically with compromised trans-Golgi and late endosome interface. We also show that Tor1p vacuolar localization and TORC1 anabolic functions, including growth promotion and phosphorylation of its direct substrate Sch9, are compromised in s-hhy mutants. Thus, an intact trans-Golgi and late endosome interface is a requisite for efficient Tor1 vacuolar localization and TORC1 function.

Photoaffinity labeling of Ras converting enzyme 1 (Rce1p) using a benzophenone-containing peptide substrate

Isoprenylation is a post-translational modification that increases protein hydrophobicity and helps target certain proteins to membranes. Ras converting enzyme 1 (Rce1p) is an endoprotease that catalyzes the removal of a three residue fragment from the C-terminus of isoprenylated proteins. To obtain structural information about this membrane protein, photoaffinity labeling agents are being prepared and employed. Here, we describe the synthesis of a benzophenone-containing peptide substrate analogue for Rce1p. Using a continuous spectrofluorometric assay, this peptide was shown to be a substrate for Rce1p. Mass spectrometry was performed to confirm the site of cleavage and structure of the processed probe. Photolysis of the biotinylated compound in the presence of membranes containing Rce1p followed by streptavidin pull-down and Western blot analysis indicated that Rce1p had been labeled by the probe. Photolysis in the presence of both the biotinylated, benzophenone-containing probe and a farnesylated peptide competitor reduced the extent of labeling, suggesting that labeling is occurring in the active site.

Breakdown of albumin and haemalbumin by the cysteine protease interpain A, an albuminase of Prevotella intermedia

BACKGROUND

Prevotella intermedia is a Gram-negative black-pigmenting oral anaerobe associated with periodontitis in humans, and has a haem requirement for growth, survival and virulence. It produces an iron porphyrin-containing pigment comprising monomeric iron (III) protoporphyrin IX (Fe(III)PPIX.OH; haematin). The bacterium expresses a 90-kDa cysteine protease termed interpain A (InpA) which both oxidizes and subsequently degrades haemoglobin, releasing haem. However, it is not known whether the enzyme may play a role in degrading other haem-carrying plasma proteins present in the gingival sulcus or periodontal pocket from which to derive haem. This study evaluated the ability of InpA to degrade apo- and haem-complexed albumin.

RESULTS

Albumin breakdown was examined over a range of pH and in the presence of reducing agent; conditions which prevail in sub- and supra-gingival plaque. InpA digested haemalbumin more efficiently than apoalbumin, especially under reducing conditions at pH 7.5. Under these conditions InpA was able to substantially degrade the albumin component of whole human plasma.

CONCLUSIONS

The data point to InpA as an efficient "albuminase" with the ability to degrade the minor fraction of haem-bound albumin in plasma. InpA may thus contribute significantly to haem acquisition by P. intermedia under conditions of low redox potential and higher pH in the inflamed gingival crevice and diseased periodontal pocket where haem availability is tightly controlled by the host.

Prevalence of gastrointestinal zoonotic helminths in dogs of Kathmandu, Nepal

INTRODUCTION: Considering the close association of dog and human beings and increasing trend of pet rearing, it is important to know the status of zoonotic helminths of pet and stray dogs and awareness of owners about this in Kathmandu, Nepal. This study was carried out to determine the prevalence of gastrointestinal zoonotic helminth parasites in dogs and to assess the awareness about canine helminth zoonoses in pet owners. MATERIALS AND METHODS: This cross-sectional study was conducted from September- 2012 to December- 2013. A total of 210 fecal samples (105 each from pet and stray dogs) were collected perrectally and examined by using Formalin-Ether Concentration method. Questionnaire survey was carried out among dog owners. RESULTS: The prevalence of gastrointestinal helminths was 46.7% (98/210). Out of 98 positive samples five different parasite species observed were Ancylostoma spp. 52.0% (51/98), Toxocara canis 41.8% (41/98), Taenia/Echinococcus spp. 15/98 (15.3%), Dipylidium caninum, 9.2% (9/98), and Trichuris vulpis, 5.1% (5/98). Prevalence was higher in stray dogs (56.2% vs. 37.1%) (p<0.05); in females (51.6% vs. 39.8%) (p>0.05); in younger dogs up to 2 years of age (56.3% vs. 35.7%) (p<0.05); in non-dewormed dogs (72.7% vs. 33.0%) (p<0.05) and in dogs sharing rooms with owner (46.1% vs. 13.8%) (p<0.05). Only 11.4% of the owners surveyed were aware about canine helminth zoonoses. CONCLUSIONS: Due to potential risk of zoonotic helminths to human beings and low level of zoonoses awareness in pet owners, there is need of generating awareness to pet owners regarding periodic anthelminthic treatment of pet dogs and other prevention and control measures. DOI: http://dx.doi.org/10.3126/ijim.v2i3.8211 Int J Infect Microbiol 2013;2(3):91-94

Distinct palmitoylation events at the amino-terminal conserved cysteines of Env7 direct its stability, localization, and vacuolar fusion regulation in S. cerevisiae

Palmitoylation at cysteine residues is the only known reversible form of lipidation and has been implicated in protein membrane association as well as function. Many palmitoylated proteins have regulatory roles in dynamic cellular processes, including membrane fusion. Recently, we identified Env7 as a conserved and palmitoylated protein kinase involved in negative regulation of membrane fusion at the lysosomal vacuole. Env7 contains a palmitoylation consensus sequence, and substitution of its three consecutive cysteines (Cys(13)-Cys(15)) results in a non-palmitoylated and cytoplasmic Env7. In this study, we further dissect and define the role(s) of individual cysteines of the consensus sequence in various properties of Env7 in vivo. Our results indicate that more than one of the cysteines serve as palmitoylation substrates, and any pairwise combination is essential and sufficient for near wild type levels of Env7 palmitoylation, membrane localization, and phosphorylation. Furthermore, individually, each cysteine can serve as a minimum requirement for distinct aspects of Env7 behavior and function in cells. Cys(13) is sufficient for membrane association, Cys(15) is essential for the fusion regulatory function of membrane-bound Env7, and Cys(14) and Cys(15) are redundantly essential for protection of membrane-bound Env7 from proteasomal degradation. A role for Cys(14) and Cys(15) in correct sorting at the membrane is also discussed. Thus, palmitoylation at the N-terminal cysteines of Env7 directs not only its membrane association but also its stability, phosphorylation, and cellular function.

Bacteriological Profile of Neonatal Sepsis in a Tertiary Level Hospital of Nepal

Introduction: Neonatal sepsis is one of the most common reasons for admission to neonatal units in developing countries. It is also a major cause of mortality in both developed and developing countries. This study was done to determine the bacterial profile causing neonatal sepsis and to assess their susceptibility pattern to various antimicrobial agents. Materials and Methods: A cross-sectional prospective study was conducted in Paropakar Maternity and Women’s Hospital, Kathmandu, Nepal among 340 neonates suspected of neonatal sepsis. Blood culture was performed and organisms were identified with Gram staining and conventional biochemical methods. Antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI). Results: The prevalence rate of neonatal sepsis was 20.3%. Among 340 neonates, 52.17% were males and 47.82% were females. Gram positive cocci were the most predominant isolates (88.40%). Among Gram positive cocci Staphylococcus epidermidis was the most common isolates (72.46%) followed by Staphylococcus aureus (7.24%), Staphylococcus saprophyticus (4.34%) and Enterococcus fecalis (4.34%). Gram negative bacilli were found in 11.60% of the growth positive samples of which E.coli and Klebsiella spp were found in 10.14% and 1.44% respectively. Sensitivity to Amikacin was highest among all types of organisms isolated. Vancomycin and Gentamycin sensitivity was highest for Gram positive and Gram negative organisms respectively. Ampicillin resistance was highest among isolates. Among the 69 isolates 48 were Multiple drug resistant. Conclusion: The predominance of Gram positive cocci particularly Coagulase negative Staphylococci is shown. Empirical antibiotic therapy should be reviewed for Multiple drug resistant strains. DOI: http://dx.doi.org/10.3126/jnps.v34i3.9183 J Nepal Paediatr Soc 2014;34(3):175-180

ENV7 and YCK3, which encode vacuolar membrane protein kinases, genetically interact to impact cell fitness and vacuole morphology

Saccharomyces cerevisiae vacuoles serve as a model for membrane fusion and fission. Yck3, a vacuolar membrane kinase, has been implicated in regulation of vacuole fusion. Recently, we established Env7 as another vacuolar membrane protein kinase with similar but nonredundant function to Yck3. Here, we report that native Env7 localizes to the vacuole independent of Yck3, where as its phosphorylation is YCK3 dependent. We also show that env7Δyck3Δ double mutant exhibits severely compromised fitness, altered cell size and bud vacuoles, and F-class vacuolar morphology. Our results establish negative genetic interactions between ENV7 and YCK3 and suggest cooperative roles for the two conserved genes in regulation of membrane dynamics. Such genetic buffering supports a critical role for membrane flux in global cell fitness.

A kinase cascade on the yeast lysosomal vacuole regulates its membrane dynamics: conserved kinase Env7 is phosphorylated by casein kinase Yck3

Membrane fusion/fission is a highly dynamic and conserved process that responds to intra- and extracellular signals. Whereas the molecular machineries involved in membrane fusion/fission have been dissected, regulation of membrane dynamics remains poorly understood. The lysosomal vacuole of budding yeast (Saccharomyces cerevisiae) has served as a seminal model in studies of membrane dynamics. We have previously established that yeast ENV7 encodes an ortholog of STK16-related kinases that localizes to the vacuolar membrane and downregulates vacuolar membrane fusion. Additionally, we have previously reported that Env7 phosphorylation in vivo depends on YCK3, a gene that encodes a vacuolar membrane casein kinase I (CKI) homolog that nonredundantly functions in fusion regulation. Here, we report that Env7 physically interacts with and is directly phosphorylated by Yck3. We also establish that Env7 vacuole fusion/fission regulation and vacuolar localization are mediated through its Yck3-dependent phosphorylation. Through extensive site-directed mutagenesis, we map phosphorylation to the Env7 C terminus and confirm that Ser-331 is a primary and preferred phosphorylation site. Phospho-deficient Env7 mutants were defective in negative regulation of membrane fusion, increasing the number of prominent vacuoles, whereas a phosphomimetic substitution at Ser-331 increased the number of fragmented vacuoles. Bioinformatics approaches confirmed that Env7 Ser-331 is within a motif that is highly conserved in STK16-related kinases and that it also anchors an SXXS CKI phosphorylation motif (328SRFS331). This study represents the first report on the regulatory mechanism of an STK16-related kinase. It also points to regulation of vacuolar membrane dynamics via a novel Yck3-Env7 kinase cascade.

Acceptance of family planning amongst patients attending Dhulikhel hospital obstetrics and gynecology department

BACKGROUND

Knowledge of contraceptive methods is an important factor for an individual to use or not use of family planning methods. In Nepal, at least one modern method of family planning is universal amongst both men and women.

OBJECTIVES

To assess the knowledge, attitude regarding various family planning methods and practice of contraceptives amongst couples attending Dhulikhel Hospital Obstetrics and Gynecology Department.

METHODS

Five hundred and fifteen couples were interviewed. Their knowledge, attitude and practice of contraception were evaluated with the help of pre-evaluated questionnaire. The other variable used were the age of the couple, parity, educational status and economic status having effect on the contraceptive acceptance were taken into consideration. Descriptive analysis was conducted to obtain percentages.

RESULTS

We observed that 74.98% of women were in the age group of 20-29 years and 59.22% of men were within the age group of 20-29 years. Teen age mothers were 17.86% and teen age fathers were 1.35%. In our study, we observed that higher the educational level better was the acceptance for family planning methods. The higher income group had less number of children compared to lesser income group. In our study, we noticed that all the couples knew about different methods of family planning, main sources of information were television, pamphlets and healthworkers. Only 16 males had undergone vasectomy and 32 women had undergone tubectomy. Fewer number of vasectomy was due to the belief that undergoing vasectomy will make the male partner weak physically. 13.20% of women preferred Depot medroxy progesterone as a temporary method of family planning, 13% of males preferred condom as a temporary method of family planning.

CONCLUSION

We conclude that education plays a vital role in the acceptance of family planning. As couples who have higher education level tend to have higher income and they have lesser number of children. They are more receptive towards counseling and agree upon the various methods of family planning. The easy accessibility to the various media like radio, television tend to make people aware of various methods of family planning.

Bacteriological Evaluation of Tonsillar Surface and Tonsillar Core Micro Flora in Patients Undergoing Tonsillectomy

Background: Acute tonsillitis is the most common disease for the ENT surgeons. Effective treatment of the tonsillitis depends on knowledge of the infecting organism but there is always a dilemma whether the antibiotics prescribed for the tonsillitis is sufficient for the different organisms in the surface and core of the tonsils.Objective: To study the microorganism on the surface and in the core of the tonsil among the patients undergoing tonsillectomy and to correlate clinical profile of the patients with various microorganisms isolated.Methods: This was a cross sectional study conducted on fifty patients’ age ranging from 3 years to 45 years. The swabs obtained from the surface of the tonsil prior to tonsillectomy and core of the tonsil post tonsillectomy were sent for isolation of micro organism and microbial susceptibility technique by standard microbial method.Results: The common age group for tonsillitis was below 15 years (n= 26) and having male predominance and more common in patients from hilly region. The commonest indication for tonsillectomy was recurrent tonsillitis (n=47). There was 82% similarity in microorganisms isolated from the surface and core of the culture. Conclusion: This study highlights that the culture from the surface of the tonsil reflects the organism in the core. Staphylococcus aureus was the commonest isolated organism in the surface and core of the tonsil.Health Renaissance 2014;12(3): 149-153

Impact of lattice mismatch and stoichiometry on the structure and bandgap of (Fe,Cr)2O3 epitaxial thin films

The structural properties of phase-pure epitaxial (Fe1-xCrx)2O3 thin films deposited on α-Al2O3(0 0 0 1) substrates by oxygen-plasma-assisted molecular beam epitaxy are investigated across the composition range using x-ray photoelectron spectroscopy, high-resolution x-ray diffraction, scanning transmission electron microscopy and electron energy loss spectroscopy, and non-Rutherford resonant elastic scattering measurements. The films possess a columnar grain structure with uniform mixing of cations on the nanometer scale. Fe-rich films are relaxed and appear to be slightly oxygen-rich, while Cr-rich films remain partially strained to the Al2O3 substrate and are found to be oxygen deficient. A model is proposed to explain the oxygen stoichiometry results based on the energetics of oxygen defect formation and rate of oxygen diffusion in the corundum lattice, and the dependence on the cation composition. Deliberately introducing residual compressive biaxial strain into (Fe1-xCrx)2O3 thin films (x = 0, 0.41, 0.52) by employing a Cr2O3 buffer layer is shown to narrow the optical bandgap, from 1.80(1) eV for relaxed (Fe0.47Cr0.53)2O3 to 1.77(1) eV for partially strained (Fe0.48Cr0.52)2O3. The relationships which are elucidated between epitaxial film structure and optical properties can be applied to bandgap optimization in the (Fe,Cr)2O3 system.

Molecular screening of major bacterial enteropathogens in human stool samples from diarrhoeal outbreak sites

BACKGROUND

V. cholera types have been implicated often in a number of occasions in diarrhoeal outbreaks in Nepal. The recent outbreak in Far Western Nepal, 2009, was also attributed primarily to V. cholera. Molecular tools were used for the first time on some of the samples from the outbreak to screen for major pathogens present in those samples.

METHODS

A commercial multiplex PCR kit based bacterial enteropathogen screening assessment was carried out on 33 human stool samples from areas of a diarrhoeal outbreak in Nepal. A total of 10 pathogenic bacterial strains at the genus level were targeted using primers provided by the manufacturer.

RESULTS

Bacterial pathogens were detected in 23 samples (69.7%). Vibrio species was detected at an overall frequency of 36.4% followed by Aeromonas spp (33.3%) and Shigella spp (15.2%) along with Verocytotoxin producing E. coli (VTEC) family (15.2%). The frequency of singly occurring pathogen in all samples was 18.2% with most of the bacterial pathogens detected in combination with other pathogens at a frequency of 60.6%. The study also shows that majority 73 (86%) of the research centers didn't start the research yet.

CONCLUSIONS

This first ever molecular screening study shows that bacterial screening is indeed possible in diarrhoeal samples. The results obtained from this study will enable monitoring of future such outbreaks using similar techniques.