Molecular basis for the increased activity of ZMS-2 serine protease in the presence of metal ions and hydrogen peroxide

Serine proteases are important enzymes widely used in commercial products and industry. Recently, we identified a new serine protease from the desert bacterium Bacillus subtilis ZMS-2 that showed enhanced activity in the presence of Zn2+, Ag+, or H2O2. However, the molecular basis underlying this interesting property is unknown. Here, we report comparative studies between the ZMS-2 protease and its homolog, subtilisin E (SubE), from B. subtilis ATCC 6051. In the absence of Zn2+, Ag+, or H2O2, both enzymes showed the same level of proteolytic activity, but in the presence of Zn2+, Ag+, or H2O2, ZMS-2 displayed increased activity by 22%, 8%, and 14%, whereas SubE showed decreased activity by 16%, 12%, and 9%, respectively. In silico studies showed that both proteins have almost identical amino acid sequences and folding structures, except for two amino acids located in the protruding loops of the proteins. ZMS-2 contains Ser236 and Ser268, whereas SubE contains Thr236 and Thr268. Replacing Ser236 or Ser268 in ZMS-2 with threonine resulted in variants whose activities were not enhanced by Zn2+ or Ag+. However, this single mutation did not affect the enhancement by H2O2. This finding may be used as a basis for engineering better proteases for industrial uses.

Characterization and Pilot-Scale Application of the ZMS-2 Serine Protease with Novel Properties for the Eco-friendly Leather Processing

Microbial alkaline proteases are dominating the global enzyme market with a share of over 65% due to their multifarious catalytic potentials. Hence, production of proteases with novel properties of commercial significance is highly desirable to meet the global enzyme demand. Here, we report the purification, characterization, and pilot-scale application of a serine protease from the desert soil bacterium Bacillus subtilis ZMS-2 with novel properties as dehairing agent in leather processing. The enzyme was purified 16.5-fold with a specific activity of 1543.5 U mg-1 and recovery percentage of 33.6% using ammonium sulfate precipitation, ion exchange, and gel filtration chromatography. The purified enzyme was characterized as a metal ion-, surfactant-, and denaturant-compatible alkaline serine protease having a molecular weight of 36.1 kDa with an optimum activity at pH 8.5 and 60 °C. The catalytic activity of the enzyme was enhanced by Zn+2 (204%), Ag+ (110%), H2O2 (123%), Triton X-100 (110%), iso-octane (109%), chloroform (110%), ethanol (105%), ethyl acetate (110%), and acetonitrile (128%). During pilot-scale applications, the optimum condition was found to be a combination of enzyme (1.5%, 460 U mL-1), sodium sulfide (2%), and calcium hydroxide (lime) (3%). Under this condition, the time required for complete dehairing was 90 min. Chemoenzymatically processed skins exhibited better physical properties than chemically processed skin, including tensile strength (16.35 ± 6.68 N/mm), ball burst (452.88 ± 6.06 N/mm), percent elongation (38.85 ± 1.06 N), tear strength (50.16 ± 4.42 N/mm), and softness (6.5 mm). Electron microscopy analysis of the treated skin showed complete removal of hairs with roots, confirming the keratin specificity of the enzyme. Moreover, the enzyme-assisted dehairing process reduced chemical oxygen demand (COD), biochemical oxygen demand (BOD), total dissolved solids (TDS), and total suspended solids (TSS) by 68, 77, 34, and 39%, respectively. Thus, the alkaline serine protease from B. subtilis ZMS-2 is a potential dehairing agent for the eco-friendly processing of animal skins on industrial scales.

In-vitro evaluation of virulence markers and antifungal resistance of clinical Candida albicans strains isolated from Karachi, Pakistan

Candidiasis is a significant fungal infection with high mortality and morbidity rates worldwide. Candida albicans is the most dominant species responsible for causing different manifestations of candidiasis. Certain virulence traits as well as its resistance to antifungal drugs contribute to the pathogenesis of this yeast. This study was designed to determine the production of some virulence factors, such as biofilm formation and extracellular hydrolytic enzymes (esterase, coagulase, gelatinase, and catalase) by this fungus, as well as its antifungal resistance profile. A total of 304 clinical C. albicans isolates obtained from different clinical specimens were identified by a conventional diagnostic protocol. The antifungal susceptibility of C. albicans strains was determined by disk diffusion technique against commercially available antifungal disks, such as nystatin 50 μg, amphotericin B 100 unit, fluconazole 25 μg, itraconazole 10 μg, ketoconazole 10 μg, and voriconazole 1 μg. The assessment of biofilm formation was determined by the tube staining assay and spectrophotometry. Gelatinase, coagulase, catalase, and esterase enzyme production was also detected using standard techniques. A total of 66.1% (201/304) and 28.9% (88/304) of C. albicans strains were susceptible-dose dependent (SDD) to nystatin and itraconazole, respectively. Among the antifungal drugs, C. albicans strains showed high resistance to ketoconazole 24.7% (75/304); however, no statistically significant relationship between the clinical origin of C. albicans isolates and antifungal drug resistance pattern was detected. For virulence factors, the majority of the C. albicans strains actively produced biofilm and all hydrolytic enzymes. Biofilm formation was demonstrated by 88% (267/304) of the strains with a quantitative mean value 0.1762 (SD ± 0.08293). However, 100% (304/304) of isolates produced catalase enzyme, 69% (211/304) produced coagulase, 66% (197/304) produced gelatinase, and 52% (157/304) produced esterase enzyme. A significant relationship between the source of specimens and biofilm formation by C. albicans was observed; nevertheless, there was no significant relationship between different sources of C. albicans strains and the production of different enzymatic virulence factors. The study found that C. albicans strains have excellent potential to produce virulence markers and resistance to antifungals, which necessitates surveillance of these opportunistic pathogens to minimize the chances of severe invasive infections.

Synthesis of poly (N-isopropyl acrylamide-co-2-acrylamido methylpropane sulfonic acid) hydrogel containing copper and nickel nanoparticles with easy recycling and efficient catalytic potential

Poly(N-isopropyl acrylamide-co-2-acrylamido methyl propane sulfonic acid) hydrogel was prepared and used as matrix for the fabrication of nickel and copper nanoparticles. Nickel and copper nanoparticles were fabricated via in situ reduction of Ni (II) and Cu (II) ions within the hydrogel matrix. The manufactured hydrogel and its corresponding composites with Ni and Cu nanoparticles were characterized by FTIR, XRD, EDX, TEM, and TGA. Thermal stability of hydrogel was found to be increased upon fabricating with metal nanoparticles. The hydrogel showed ability to absorb water 63 times of its weight in dried form. The Ni and Cu nanoparticles were observed to be well dispersed, spherical in shape and most of them were having diameters in the range of 12.5 to 38.8 nm and 58 to 102 nm, respectively. The as-prepared hydrogel-nickel and hydrogel-Cu nanocomposite were used as catalysts for the reduction of a toxic pollutant 4-nitrophenol. At 25 °C, the reduction of 4-NP was found to proceed with apparent rate constant (k app) of 0.107 and 0.122 min−1 in the presence of composite containing Ni and Cu nanoparticles, respectively. However, k app was increased with corresponding increase in temperature and its maximum value was found to be 0.815 min−1 at 88 °C with catalyst containing Ni nanoparticles. The formation of well dispersed Ni and Cu nanoparticles in the prepared hydrogel reflected that this hydrogel system can act as efficient stabilizing agent along with acting as a reactor medium. Recycling potential of catalysts was studied for five successive cycles.

Public Perceptions of Current COVID-19 Vaccinations. Results of a Pilot Survey

Introduction

We conducted a cross-sectional survey as a part of an educational program in collaboration with the Global Thrombosis Forum (GTF), an affiliate of North American Thrombosis Forum (NATF), and Loyola University about public perceptions of COVID-19 and COVID-19 vaccinations in the US. In this study, we are reporting the results of this survey.

Materials and Methods

The survey, in the form of a questionnaire, has been developed by GTF and faculty members. A prepared questionnaire was sent to the members of the Georgia and Illinois communities.

Results

In our current study, the COVID-19 vaccine willingness rate was 94.5% and vaccination rate was 90.9%. In multivariate analysis believing to have enough information about the safety and efficacy of COVID-19 vaccines (OR: 3.730, 95% CI: 1.199–11.603, p: 0.023) and gender (OR: 0.123, 95% CI: 0.016–0.967, p: 0.046) were significant predictors for vaccine willingness. Previous COVID-19 infection (OR: 0.215, 95% CI: 0.061–0.758, p: 0.017), moderate and severe effects of COVID-19 pandemic on participant's life (OR: 4.631, 95% CI 1.681–12.760, p: 0.003) and believing to have enough information about the safety and efficacy of COVID-19 vaccines (OR: 4.119, 95% CI: 1.508–11.253, p: 0.006) were significant predictors for final vaccination status.

Conclusion

In conclusion, currently vaccination remains one of the most effective tools in the fight against the COVID-19 pandemic. The vaccine hesitancy is a complex phenomenon that is driven by individuals' perceptions of safety, and efficiency of the vaccines. We must continue to educate the public and communities that vaccines are safe, that they are effective and that they are still required even after a COVID-19 infection.

Characterization of wheat-Thinopyrum bessarabicum genetic stock for stripe rust and Karnal bunt resistance

Utilization of modern breeding techniques for developing high yielding and uniform plant types ultimately narrowing the genetic makeup of most crops. Narrowed genetic makeup of these crops has made them vulnerable towards disease and insect epidemics. For sustainable crop production, genetic variability of these crops must be broadened against various biotic and abiotic stresses. One of the ways to widen genetic configuration of these crops is to identify novel additional sources of durable resistance. In this regard crops wild relatives are providing valuable sources of allelic diversity towards various biotic, abiotic stress tolerance and quality components. For incorporating novel variability from wild relative's wide hybridization technique has become a promising breeding method. For this purpose, wheat-Th. bessarabicum amphiploid, addition and translocation lines have been screened in field and screen house conditions to get novel sources of yellow rust and Karnal bunt resistant. Stripe rust screening under field conditions has revealed addition lines 4JJ and 6JJ as resistant to moderately resistant while addition lines 3JJ, 5JJ, 7JJ and translocation lines Tr-3, Tr-6 as moderately resistant wheat-Thinopyrum-bessarabicum genetic stock. Karnal bunt screening depicted addition lines 5JJ and 4JJ as highly resistant genetic stock. These genetic stocks may be used to introgression novel stripe rust and Karnal bunt resistance from the tertiary gene pool into susceptible wheat backgrounds.

The COVID-19 Pandemic and the Need for an Integrated and Equitable Approach: An International Expert Consensus Paper

BACKGROUND

 One year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic by the World Health Organization (WHO) and despite the implementation of mandatory physical barriers and social distancing, humanity remains challenged by a long-lasting and devastating public health crisis.

MANAGEMENT

 Non-pharmacological interventions (NPIs) are efficient mitigation strategies. The success of these NPIs is dependent on the approval and commitment of the population. The launch of a mass vaccination program in many countries in late December 2020 with mRNA vaccines, adenovirus-based vaccines, and inactivated virus vaccines has generated hope for the end of the pandemic.

CURRENT ISSUES

 The continuous appearance of new pathogenic viral strains and the ability of vaccines to prevent infection and transmission raise important concerns as we try to achieve community immunity against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and its variants. The need of a second and even third generation of vaccines has already been acknowledged by the WHO and governments.

PERSPECTIVES

 There is a critical and urgent need for a balanced and integrated strategy for the management of the COVID-19 outbreaks organized on three axes: (1) Prevention of the SARS-CoV-2 infection, (2) Detection and early diagnosis of patients at risk of disease worsening, and (3) Anticipation of medical care (PDA).

CONCLUSION

 The "PDA strategy" integrated into state policy for the support and expansion of health systems and introduction of digital organizations (i.e., telemedicine, e-Health, artificial intelligence, and machine-learning technology) is of major importance for the preservation of citizens' health and life world-wide.

Prevalence and association of HBV and HCV infection with cardiovascular disease risk factors in a peri-urban population

OBJECTIVE

To investigate the possible associations of hepatitis B and C virus infection with cardiovascular disease risk factors inperi-urban population.

Methods

The cross-sectional study was conducted from February to December 2016 in the periurban low-resource locality of Bin Qasim Town in Karachi. Serum samples were screened for hepatitis B surface antigen and hepatitis C virus antibodies. Anthropometric measurements were taken and markers related to cardiovascular disease were examined. Association of the two hepatitis virus infections with cardiovascular diseasewere investigated by anaylsing the data using SPSS 16.

RESULTS

There were 691 subjects. Serum triglyceride levels were significantly low in patients with hepatitis B virus (p<0.05). Those with hepatitis C virus had markedly low total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride levels (p<0.05 each), whereas random blood sugar and body mass index values were significantly high (p<0.05 each. Hepatitis C virus infection was positively associated with body mass index and random blood glucose, and inversely associated with total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol(p< 0.05 each).

CONCLUSIONS

Hepatitis B virus infection showed a significant inverse association with triglyceride levels. However, hepatitis C virus infection was positively associated with body mass index and random blood sugar, and inversely associated with total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol levels.

Dataset for homologous proteins in Drosophila melanogaster for SARS-CoV-2/human interactome

Animal modelling for infectious diseases is critical to understand the biology of the pathogens including viruses and to develop therapeutic strategies against it. Herein, we present the sequence homology and expression data analysis of proteins found in Drosophila melanogaster that are orthologous to human proteins, reported as components of SARS-CoV-2/Human interactome. The dataset enlists sequence homology, query coverage, domain conservation, OrthoMCL and Ensembl Genome Browser support of 326 proteins in D.melanogaster that are potentially orthologous to 417 human proteins reported for their direct physical interactions with 28 proteins encoded by SARS-CoV-2 genome. Expression of these D.melanogaster orthologous genes in 26 anatomical positions are also plotted as heat maps in 27 sets, corresponding to the potential protein interactors for each viral protein. The data could be used to direct experiments and potentially predict their phenotypic and molecular outcome in order to dissect the biological roles and molecular functionality of SARS-CoV-2 proteins in a convenient animal model system like D.melanogaster.

Molecular docking between human TMPRSS2 and SARS-CoV-2 spike protein: conformation and intermolecular interactions

Entry of SARS-CoV-2, etiological agent of COVID-19, in the host cell is driven by the interaction of its spike protein with human ACE2 receptor and a serine protease, TMPRSS2. Although complex between SARS-CoV-2 spike protein and ACE2 has been structurally resolved, the molecular details of the SARS-CoV-2 and TMPRSS2 complex are still elusive. TMPRSS2 is responsible for priming of the viral spike protein that entails cleavage of the spike protein at two potential sites, Arg685/Ser686 and Arg815/Ser816. The present study aims to investigate the conformational attributes of the molecular complex between TMPRSS2 and SARS-CoV-2 spike protein, in order to discern the finer details of the priming of viral spike protein. Briefly, full length structural model of TMPRSS2 was developed and docked against the resolved structure of SARS-CoV-2 spike protein with directional restraints of both cleavage sites. The docking simulations showed that TMPRSS2 interacts with the two different loops of SARS-CoV-2 spike protein, each containing different cleavage sites. Key functional residues of TMPRSS2 (His296, Ser441 and Ser460) were found to interact with immediate flanking residues of cleavage sites of SARS-CoV-2 spike protein. Compared to the N-terminal cleavage site (Arg685/Ser686), TMPRSS2 region that interact with C-terminal cleavage site (Arg815/Ser816) of the SARS-CoV-2 spike protein was predicted as relatively more druggable. In summary, the present study provides structural characteristics of molecular complex between human TMPRSS2 and SARS-CoV-2 spike protein and points to the candidate drug targets that could further be exploited to direct structure base drug designing.

Luffa cylindrica Immobilized with Aspergillus terreus QMS-1: an Efficient and Cost-Effective Strategy for the Removal of Congo Red using Stirred Tank Reactor

Microbial populations within the rhizosphere have been considered as prosperous repositories with respect to bioremediation aptitude. Among various environmental contaminants, effluent from textile industries holds a huge amount of noxious colored materials having high chemical oxygen demand concentrations causing ecological disturbances. The study was aimed to explore the promising mycobiome of rhizospheric soil for the degradation of azo dyes to develop an efficient system for the exclusion of toxic recalcitrants. An effluent sample from the textile industry and soil samples from the rhizospheric region of Musa acuminata and Azadirachta indica were screened for indigenous fungi to decolorize Congo red, a carcinogenic diazo dye, particularly known for its health hazards to the community. To develop a bio-treatment process, Aspergillus terreus QMS-1 was immobilized on pieces of Luffa cylindrica and exploited in stirred tank bioreactor under aerobic and optimized environment. Quantitative estimation of Congo red decolorization was carried out using UV-Visible spectrophotometer. The effects of fungal immobilization and biosorption on the native structure of Luffa cylindrica were evaluated using a scanning electron microscope. A. terreus QMS-1 can remove (92%) of the dye at 100 ppm within 24 h in the presence of 1% glucose and 1% ammonium sulphate at pH 5.0. The operation of the bioreactor in a continuous flow for 12 h with 100 ppm of Congo red dye in simulated textile effluent resulted in 97% decolorization. The stirred tank bioreactor was found to be a dynamic, well maintained, no sludge producing approach for the treatment of textile effluents by A. terreus QMS-1 of the significant potential for decolorization of Congo red.

Structural variations in human ACE2 may influence its binding with SARS-CoV-2 spike protein

The recent pandemic of COVID‐19, caused by SARS‐CoV‐2, is unarguably the most fearsome compared with the earlier outbreaks caused by other coronaviruses, SARS‐CoV and MERS‐CoV. Human ACE2 is now established as a receptor for the SARS‐CoV‐2 spike protein. Where variations in the viral spike protein, in turn, lead to the cross‐species transmission of the virus, genetic variations in the host receptor ACE2 may also contribute to the susceptibility and/or resistance against the viral infection. This study aims to explore the binding of the proteins encoded by different human ACE2 allelic variants with SARS‐CoV‐2 spike protein. Briefly, coding variants of ACE2 corresponding to the reported binding sites for its attachment with coronavirus spike protein were selected and molecular models of these variants were constructed by homology modeling. The models were then superimposed over the native ACE2 and ACE2‐spike protein complex, to observe structural changes in the ACE2 variants and their intermolecular interactions with SARS‐CoV‐2 spike protein, respectively. Despite strong overall structural similarities, the spatial orientation of the key interacting residues varies in the ACE2 variants compared with the wild‐type molecule. Most ACE2 variants showed a similar binding affinity for SARS‐CoV‐2 spike protein as observed in the complex structure of wild‐type ACE2 and SARS‐CoV‐2 spike protein. However, ACE2 alleles, rs73635825 (S19P) and rs143936283 (E329G) showed noticeable variations in their intermolecular interactions with the viral spike protein. In summary, our data provide a structural basis of potential resistance against SARS‐CoV‐2 infection driven by ACE2 allelic variants.

Structural modelling and molecular superimposition analyses shows variations in the interactions between proteins encoded by some human ACE2 alleles and SARS‐CoV‐2 spike protein. The findings provide direction to the targeted allele screening in COVID‐19 patients, which could further be used in predicting the prognosis of the disease and allocation of the health resources.

Bacillus tequilensis ZMS-2: A novel source of alkaline protease with antimicrobial, anti-coagulant, fibrinolytic and dehairing potentials

Emerging resistance to existing antimicrobial agents is one of the growing concerns and a serious problem for public health globally. Currently available antimicrobial agents are potent and effective but surfacing resistance to these drugs has not been ruled out so far. Therefore, it is utmost important to explore new bioactive compounds from natural sources to meet future needs. The present study was designed to produce, optimize, characterize and evaluate antimicrobial, fibrinolytic and anti-coagulant potential of a new alkaline protease. Proteolytic strain from desert soils of Tharparkar, Pakistan was subjected to 16S rDNA sequencing and identified as Bacillus tequilensis ZMS-2(Genbank Accession No. MK101013). During submerged fermentation at 37ºC, maximum enzyme production (454 U/ml) was observed with 24h old inoculum. The best incubation time was 72h (544 U/ml), optimum inoculum size and pH was 10% at pH 8 with 494 and 506 U/ml, respectively. The best carbon source was starch (571 U/ml), while ideal substrate was wheat bran (536 U/ml). Optimal temperature and pH for proteolytic activity was 60ºC (420 U/ml) and 8 (332 U/ml). Alkaline protease showed antibacterial activity against Staphylococcus aureus (27mm), Bacillus licheniformis (20mm), Klebsiella pneumoniae (17mm) and Escherichia coli (15mm). The strain B. tequilensis ZMS-2 also exhibited anticoagulant, fibrinolytic and dehairing potential suggesting application of its protease in various industries.

Non-albicans Candida species: Emergence of neglected pathogens among population of Karachi

Candida albicans was considered as the principal cause of opportunistic candidiasis but nowadays, neglected non-albicans Candida (NAC) species are evolving as more virulent and drug resistant strains. This research was intended to assess pervasiveness of candidiasis mainly caused by NAC species in Karachi city. A total of 562 clinical isolates of Candida spp. collected during the period of one year were identified by microscopic as well as morphological (germ tube formation, characteristics on CHROM agar and Corn meal agar) and Biochemical (sugar assimilation and fermentation) characteristics. Doubtful species were further identified by using Remel RapIDTM yeast plus kit. The results were statistically analyzed by SPSS 16.0 version software. Isolated strains of candida revealed slight predominance of C. albicans (54.5%) over non- albicans Candida species (45.5%). Among NAC species, C. tropicalis and C. glabrata were isolated as the predominant species. These clinical species were procured mainly from urine samples of females (73.7%) of age group 20-30 years. No significant correlations exist between Candida species and their months of isolation as well as their isolation from different districts of Karachi. Emergence of NAC species may predict an upcoming threat in health care facilities and hence, require prompt management and accurate identification to suggest empirical antifungal therapy.

Antimicrobial potential of newly isolated Aspergillusterreus MK-1: An approach towards new antibiotics

OBJECTIVE

To attempt discovering new bioactive metabolites from fungal sources.

METHODS

The exploratory study was conducted at the Department of Microbiology, Federal Urdu University for Arts, Science and Technology, Karachi from January 2016 to November 2017and comprised of soil samples collected from rhizosphere region of different garden plants from the city. Fungi were screened for production of antibiotics by testing cell-free culture filtrates obtained by Shake-flask fermentation technique. Agar-Well diffusion assay method was used to evaluate antagonistic activity against pathogenic microorganisms.

RESULTS

Bioactive compounds extracted by ethyl acetate and thin layer chromatography revealed mixture of compounds in the crude extract. AspergillusterreusMK-1 showed significant inhibition of medically important test pathogens namely Staphylococcus aureus, Pseudomonas aeruginosa, Escherichiacoli, Salmonella typhi, Micrococcus luteus, Streptococcus epidermidis, Bacillus subtilis, Candida albicans and Aspergillusniger. The best biological activity of crude ethyl acetate extract was observed against Pseudomonas aeruginosa (63mm).

CONCLUSIONS

Newly isolated AspergillusterreusMK-1 emerged as a potent candidate for the production of antimicrobial compounds.

Fungal contamination in smokeless tobacco products traditionally consumed in Pakistan

OBJECTIVE

To isolate potential pathogenic fungi from smokeless tobacco products.

METHODS

The study was conducted from January 2015 to February 2017 during which samples of smokeless tobacco products such as Mainpuri, Tambako, Khiwam, Gutkha, Naswar and Mawa etc. were collected from different cities of Pakistan. The samples were tested for fungal contamination by spread plate method. Different strains of fungi were isolated and identified on the basis of their macroscopic as well as microscopic characteristics. The fungal strains isolated were also screened for their susceptibility to commonly used antifungal drugs by disc diffusion method.

RESULTS

Of the 600 samples collected, 300(50%) were from Sindh, 70(11.7%) Balochistan, 74(12.3%) from Khyber Pakhtunkhwa, 105(17.5%) from Punjab and 51(8.5%) from Azad Kashmir. In terms of products, there were 404(67.3%) samples of Naswar, 69(11.5%) Patti, 40(6.6%) Khiwam, 35(5.8%) Mawa, 32(5.3%) Gutkha, and 20(3.3%) Mainpuri samples. Different species of Aspergillus were predominantly isolated followed by Penicillium, Mucor, Sepedonium and Trichophyton. The isolated strains of Aspergillus also revealed resistance against many commonly-used anti-fungals such as Amphotericin B and Itraconazole..

CONCLUSIONS

There was high prevalence of opportunistic fungi in study samples, posing a threat for human health which requires prompt notice and management.

The Pattern of Psychiatric Morbidity in an Outpatient Child Psychiatry Clinic: A Cross-sectional, Descriptive Study from a Tertiary Care Hospital in Kashmir, North India

BACKGROUND

Psychiatric disorders are ubiquitous and affect not only adults but also children and adolescents. The age factor plays an important role in the pattern of these psychiatric disorders. The objective of our study was to find the pattern of psychiatric morbidity in children and adolescents at the child and adolescent outpatient service of a tertiary care hospital.

MATERIALS AND METHODS

A semi-structured questionnaire was used to record the sociodemographic status. The state of mental health and psychiatric morbidity was assessed after a thorough clinical assessment. Intelligence quotient was assessed by a clinical psychologist as and when needed. All the diagnoses were made on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4^th Edition, Text Revision criteria.

RESULTS

A total of 529 patients were included. Most patients belonged to the age group of 6-16 years (70.5%). Boys (67.9%) outnumbered girls. Most of the patients were from rural background (56.7%) and from nuclear families (53%). Attention-deficit hyperactivity disorder (31%) and mental retardation (29%) were the most frequent diagnoses, followed by pervasive developmental disorders (10%). Comorbidity was present in about 18% of our patients.

CONCLUSION

The child psychiatry is gaining acceptance, and children and adolescents with minor mental health issues are being identified and referred for specialized services.

ID:2034 Structural and Functional Polymorphism in Hepatitis B Virus Oncogene, HBx

Background: HBV is now firmly associated with the incidence of Hepatocellular Carcinoma. This oncogenic potential of HBV is primarily due to an oncogene referred to as HBx. The present study deals with the sequential and structural variations found in the HBx protein encoded by the genomes of different HBV genotypes.   Methods: In total 5991 sequences of HBx belonging to different genotypes of HBV were aligned to procure consensus sequences of each genotype. The sequence was than used to construct molecular structure of HBx employing iterative threading alignment. The models were optimized and refined for the structural and thermodynamic parameters. The selected models were used to develop structures of HBx of each genotype which were in turn compared for their structural attributes, dimer formation and molecular interactions with p53.   Results: The sequence alignment reveals considerable conservation in the HBx sequences of different genotypes. The strongly conserved C-terminal region is a component of p53 interaction region of HBx. The most diverged region was found to be dimerization region spanning 25 to 50 aa. Structurally, HBx molecule has found to be nearly disordered except the C-terminal p53 binding region that adopts helical conformation. This in turn may explain in part the promiscuous nature of HBx in terms of binding with multiple binding partners. These observations have been further verified by GlobPlot analysis. The disordered region potentially rendered variations in the intra and inter molecular complexes of HBx as observed by molecular docking analysis.   Conclusion: The data highlights the variations in the structural characteristics of HBx that underscores the variations in the pathological and oncogenic consequences of HBV infections rendered by different HBV genotypes.

Isolation of potentially pathogenic fungi from selected pigeons' feeding sites in Karachi: A new dimension to health hazard

OBJECTIVE

To determine the presence of pathogenic fungal strains in areas where pigeons are present in a large number.

METHODS

This study was conducted at the Federal Urdu University of Arts, Science and Technology, Karachi, from February 2015 to March2016, and comprised samples of soil contaminated with pigeons' excreta. The samples were collected from 20 different pigeon-feeding places in the city. These samples were processed for the isolation and identification of fungi by using standard conventional methods. The fungal strains isolated were also tested for their susceptibility to commonly used antifungal agents by disc diffusion technique.

RESULTS

There were 105 samples. A wide variety of fungal strains belonging to different genera of Aspergillus, Rhizopus, Penicillium, Fusarium and Candida were isolated and identified by using conventional methods. The antifungal resistance pattern of these strains also depicts emergence of resistance against commonly used antifungal agents such as amphotericin B and fluconazole.

CONCLUSIONS

The soil and air of places densely populated with pigeons were found to be loaded with fungal spores and many of them were potential pathogens.

Biophysicochemical characterization of Pyocin SA189 produced by Pseudomonas aeruginosa SA189

Pseudomonas aeruginosa, in spite of being a ubiquitous organism (as it is found in soil, water, and humans), is also an opportunistic pathogen. In order to maintain its diversity in the community, it produces various toxic proteins, known as, bacteriocins. In the present study, pyocin SA189, which is a bacteriocin produced by P. aeruginosa SA189 (isolated from a clinical sample) was characterized. P. aeruginosa SA189, as identified by the conventional and 16S rRNA gene amplification, produced pyocin SA189 of molecular weight of 66 k Da. The pyocin showed antimicrobial activity against several clinically relevant Gram-positive and Gram-negative bacteria and was substantially stable for wide ranges of temperature and pH. Furthermore, the pyocin also retained its biological activity upon treatment with metal ions, organic solvents, and various proteolytic and lipolytic enzymes. The data from the growth kinetics indicated that the maximum bacteriocin production occurred in the late log phase. Overall, our results signify the potential of pyocin SA189 as a bio-control agent.

Multi-drug resistant pseudomonas aeruginosa: a threat of nosocomial infections in tertiary care hospitals

OBJECTIVE

To determine the resistance patterns of Pseudomonas aeruginosa to currently available anti-pseudomonal drugs and frequency of nosocomial infections caused by multi drug resistant Pseudomonas aeruginosa in hospitals.

METHODS

Clinical isolates of Pseudomonas aeruginosa were collected from patients admitted in different hospitals of Karachi between July 2012 and June 2013. The isolates were identified by conventional and Analytical Profile Index 20NE kit methods while the antibiograms of these isolates were determined by Kirby-Bauer disc diffusion method.

RESULTS

Of the 204 isolates, 79(39%) were obtained from intensive care units: Overall, 135(66%) isolates belonged to men, and 35(17.2%) belonged to 10-15 year age group. The overall antibiogram pattern showed high resistance to commonly used antibiotics like Ofloxacin 125(61.3%), Cefepime 117(57.3%), Ceftazidime 110(53.9%), Amikacin 108(53%). Of all the isolates, 129(63.2%) were considered multidrug resistant. The most effective antibiotics were Colistin, Polymyxin B and Meropenem.

CONCLUSION

Increasing multidrug resistance among nosocomial pathogens is an alarming situation in a hospital setting and requires prompt management of these cases.

The activity of antioxidant enzymes in response to salt stress in safflower (Carthamus tinctorius L.) and sunflower (Helianthus annuus L.) seedlings raised from seed treated with chitosan

BACKGROUND

Salt tolerance is a complex trait which involves the coordinated action of many genes that perform a variety of functions, such as ion sequestration, metabolic adjustment, osmotic adjustment and antioxidative defence. In this article, the growth and the generation and scavenging of reactive oxygen species (ROS) under normal (ECiw [Electrical conductivity of irrigation water] = 0.5 dS m(-1)) and salt stress conditions (ECiw = 3.4, 6.1, 8.6 and 10.8 dS m(-1) ) in relation to the priming of seeds of the two important oil yielding crops, i.e. safflower and sunflower, with different concentrations of chitosan [0% (control), 0.25%, 0.50%, 0.75%] is discussed.

RESULTS

Induced salinity stress significantly decreased germination percentage, germination rate, length and weight of root and shoot, and protein content. Proline content, malondialdehyde content (MDA), catalase (CAT) and peroxidase (POX) activity increased at 10.8 dS m(-1). Under control conditions there were no significant differences in germination percentage among different concentrations of chitosan, whereas CAT and POX activity were increased by low concentrations of chitosan. With increasing salt stress, low concentrations of chitosan increased germination percentage but decreased MDA and proline contents and CAT and POX activity.

CONCLUSION

Generation of ROS seems to be unavoidable under normal conditions and the activity of antioxidant enzymes in plants varies in terms of ROS generation under salt stress. However, the data indicate that plants subjected to salt stress-induced oxidative stress and the low concentrations of chitosan exhibited positive effects on salt stress alleviation through the reduction of enzyme activity in both crops.

Evolutionary root defines the structural basis of high and low level vancomycin resistance in enterococci

D-alanyl-D-lactate (Dlac) and D-alanyl-D-serine (Dser) ligases respectively mediates high and low level vancomycin resistance among enterococci. To date, the evolutionary relationship of both ligases is largely unaddressed. Also poorly understood are the molecular differences in the magnitude of vancomycin resistance. To address the mention, we constructed the phylogenetic tree of all vancomycin resistance conferring ligases with the wild type ligases (Dala). Multiple sequence alignment and tertiary structures of the structurally unresolved proteins were constructed by homology modeling. Phylogenetic tree revealed that both Dlac and Dser are profoundly different from Dala as a result of continuous selection pressure. Separate clustering of Dlac and Dser also highlighted the structural basis of molecule in maintaining different level of resistance as exhibited by the bacteria. This notion was further augmented as the functionally key region, omega loop (ω-loop), was found relatively more structured in only Dlac. Moreover, the critically active residue, His-243/244, was also noticed to be restricted in Dlac and found replaced by non polar residues in Dser. The present study not only provides protein structural explanation of the different intensities of vancomycin resistance among enterococci, but also presents yet another example for the scope of evolutionary science in biomedicine.

Coat protein gene diversity among Chrysanthemum virus B isolates from India

The complete coat protein (CP) sequences from 29 Indian isolates of Chrysanthemum virus B (CVB) were determined and analysed in relation to other previously characterized carlaviruses. The CP genes of the Indian CVB isolates were highly heterogeneous, sharing nucleotide sequence identities of 74-98%. Based on phylogenetic analyses, the isolates formed three groups potentially representing either two or three major CVB strain groupings. Recombination analysis revealed at least one definite recombination event involving the exchange of sequences between members of different groups. To our knowledge this is the first reported evidence of homologous recombination in carlaviruses.

Serum leptin levels in pregnant Pakistani females: relationship with body mass index and placental weight

OBJECTIVE

To determine the serum leptin levels in Pakistani pregnant subjects at the time of delivery and to ascertain the relationship between serum leptin levels and related variables (weight, body mass index, placental weight, gestational age, parity) at delivery.

SETTING

Lady Dufferin Hospital, and Ziauddin Hospital Karachi.

METHODS

Leptin concentration was measured in 110 subjects from venous samples, using Active Human ELISA Kit (DSL-10-23100). Samples were selected according to the availability.

RESULTS

Mean maternal weight, body mass index and placental weight were 64.3 +/- 13.8 kg, 27.1 +/- 5.8 kg/m2 and 523.5 +/- 90 gm, respectively. Gestational age was 36-41 weeks and maternal age was 18-35 years. Mean serum leptin level was 27.9 +/- 18.1 ng/ml. Serum leptin levels were found to be positively correlated with body weight (r = 0.73, p < 0.01), body mass index (r = 0.80, p < 0.01) and placental weight (r = 0.34, p < 0.05). Increased leptin levels were found in multigravida mothers (mean 30.2 +/- 17.5) than in primigravida mothers (23.1 +/- 18.9).

CONCLUSION

Our results suggest that leptin does play role in body weight and energy regulation during pregnancy. The significant positive correlation between leptin and placental weight suggests that placenta may be the site of synthesis and/or secretion of leptin during pregnancy.

Head lice infestation in some urban localities of NWFP, Pakistan

The prevalence of head lice infestation was estimated among the general population of four urban localities in the North West Frontier Province of Pakistan during 1986. Altogether 1002 persons (656 females, 346 males) were screened by visual inspection and combing of the head. The overall infestation rate was 36.7%, with females showing a higher prevalence (41.5%) than males (27.7%). The prevalence did not differ significantly with locality, and exhibited only a slight seasonal variation. Pediculosis was high in the five to 19 year old age-group, beyond which it decreased, gradually in females and abruptly in males. Higher rate of infestation in females could be attributed to their long hair. A significant negative association between pediculosis and dandruff was noticed in males but not in females. Crowding and low level of education, which reflect poor socio-economic status, apparently contributed to higher rate of infestation. Prevalence was directly related to the number of children per family, suggesting that school children perhaps play an important role in the distribution of lice. Intensity of infestation, like prevalence, was higher in females than males, and decreased with age in both sexes.