Population genetic structure of Bactrocera dorsalis based on cox1 sequences from Bangladesh and neighboring countries

Oriental fruit fly, Bactrocera dorsalis (Hendel), is a destructive and highly polyphagous invasive fruit fly species of numerous fruit crops in global agriculture. Population genetic structure of this species from five different locations of Bangladesh was examined with other samples (collected from GenBank) from 15 sites of neighboring Asian countries. A fragment of 770 bp mitochondrial DNA cox1 was used to investigate the genetic diversity and the relationship between genetic patterns and geographical distribution of B. dorsalis. A total of 232 variable sites (33.23% of the 698 bp aligned consensus sequences) and 419 unique haplotypes were identified from 710 individuals. Indices of genetic diversity suggested that without exclusion from geographical areas, B. dorsalis retained a relatively high degree of genetic diversity. A demographic assessment [Tajimas’ D test, Fu’s Fs test and sum of square deviation (SSD values)] revealed that both current and historical variables performed a significant role in deciding the weak genetic structure with some exceptions. In Bangladesh, high levels of genetic diversity with a weak genetic structure indicated that the severity of this pest might increase in the future. Proper management techniques should be taken to overcome the future severity of this kind of destructive insect.     

In silico investigation on alkaloids of Rauwolfia serpentina as potential inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase

Present work aimed to investigate the in silico activity of the alkaloids of roots of Rauwolfia serpentina as inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR). For this purpose, the three-dimensional (3D) structure of the protein HMGCR (PDB ID: 1HW9) was downloaded from Protein Data Bank (PDB) database, as a target enzyme. The structures of twelve alkaloids from the roots of R. serpentina were selected as ligands and docked with the selected HMGCR enzyme using Molegro Virtual Docker (MVD) software. The software ‘MVD’ computes the binding (atom) energies of selected protein (enzyme) and each ligand at minimum energetic conformation state by using the PLP (Piecewise Linear Potential) scoring mechanism. Docking results of twelve tested alkaloids showed that five alkaloids including compound 1 (ajmalicine), 2 (reserpine), 3 (indobinine), 4 (yohimbine), and 5 (indobine) have displayed the highest MolDock scores and best fit within the prominent active site residues (positioned between 684 and 692 of cis-loop) of HMGCR. According to the lowest MolDock energies obtained through non-covalent interactions of alkaloids with HMGCR, these are characterized to be the potential inhibitors of HMGCR. Therefore, the alkaloids from R. serpentina can effectively suppress the cholesterol biosynthesis pathway through inhibition of HMGCR and can serve as potential lead compounds for the development of new drugs for the treatment of hyperlipidaemia.     

A comparative study of biological potentiality and EAC cell growth inhibition activity of Phyllanthus acidus (L.) fruit pulp and seed in Bangladesh

Medicinal plant-derived bioactive compounds have recently gained more interest in biological research as an important source of novel drug candidates. Phyllanthus acidus (L.) is a widely distributed herbal medicinal plant naturally used in Ayurvedic medicine in Bangladesh. The present study focused on exploring the biological potential as well as the inhibitory effect of EAC cell growth with a comparative analysis between Phyllanthus acidus fruit pulp and seed. Crude methanol extract of P. acidus (MEPA) fruit pulp and seed was assessed as DPPH and NO free radical scavengers. While Brine Shrimp lethality bioassay, the standard protocol of phytochemical screening and hemagglutination assay were performed successively to determine the toxic effect on normal cells, the identification of some crucial phytochemicals, and the existence of lectin protein. EAC (Ehrlich’s Ascites Carcinoma) cell growth inhibition was determined by hemocytometer and morphological changes of EAC cells were observed by a fluorescence microscope using Swiss albino mice. The IC₅₀ value of MEPA fruit pulp and seed was obtained as 57.159 µg/ml and 288.743 µg/ml respectively where minimal toxic effects on Brine Shrimp nauplii demonstrates that it is a good source of natural antioxidant compounds. Again, MEPA fruit pulp and seed-mediated effective agglutination of mouse blood erythrocyte strongly support the presence of lectin protein. Furthermore, MEPA fruit pulp and seed extract-treated EAC cells showed 65.71% and 28.57% growth inhibition respectively. The fluorescent microscopic examination of EAC cells treated with MEPA fruit pulp has shown more remarkable structural changes in the nucleus than that of seed. Based on the above findings, the present study reveals that MEPA fruit pulp can be considered as a novel biological candidate for the treatment of fatal diseases shortly.     

Knowledge,attitude and practices of healthcare professionals of Riyadh,Saudi Arabia towards covid-19: A cross-sectional study

Background & objectivesCOVID-19 is an emerging pandemic that necessitates the implementation of effective infection prevention and control steps. The knowledge, attitudes, and practices (KAP) of healthcare professionals toward COVID-19 affect their compliance to prevention and control initiatives. During the evolving pandemic, we examined the KAP among healthcare professionals against COVID-19 in this research.Materials and methodsThis was a cross-sectional study conducted among Riyadh region health care professionals from the beginning of December 2020 to the end of February 2021 using a validated self-administered questionnaire. The knowledge questionnaire contained questions about COVID-19 clinical characteristics, prevention, and management. The evaluation of attitudes and practices included questions regarding actions and adjustments in COVID-19 response activities. Knowledge scores were measured and compared using demographic characteristics, as well as attitudes and practices toward COVID-19. Using SPSS-IBM 25, bivariate statistics were done to analyze the data.Results146 healthcare professionals completed the survey. Physicians were the most prominent party in the survey, accounting for 74 (51 percent), followed by nurses 44 (30 percent) and pharmacists 28 (19 percent). The participants' average age was 39.69 ± 8.48 years. The participant's mean knowledge, attitude, and practice scores were 11.43 ± 1.34, 3.89 ± 0.93, and 3.85 ± 0.81, respectively. With a positive attitude, the mean knowledge score was 11.52, and with proper practice, it was 11.32. With an improvement in knowledge, the attitude score increased significantly (r = 0.172, P = 0.001). Besides, there was a greater association between attitudes and practices (r = 0.170, P = 0.029). A significant enhancement in the practice score of the professionals was noted with an increase in knowledge score (r = 0.095, P = 0.010), an indicator for a positive correlation between practice and knowledge scores.Interpretation & conclusionHealthcare practitioners have a good understanding of COVID-19. Improved knowledge and a positive attitude toward COVID-19 infection are linked to appropriate practice. There is a need for more manpower, better COVID-19 management training, and strategies to reduce anxiety among healthcare professionals.     

Irxl1 mutant mice show reduced tendon differentiation and no patterning defects in musculoskeletal system development

Irxl1 (Iroquois-related homeobox like-1) is a newly identified three amino-acid loop extension (TALE) homeobox gene, which is expressed in various mesoderm-derived tissues, particularly in the progenitors of the musculoskeletal system. To analyze the roles of Irxl1 during embryonic development, we generated mice carrying a null allele of Irxl1. Mice homozygous for the targeted allele were viable, fertile, and showed reduced tendon differentiation. Skeletal morphology and skeletal muscle weight in Irxl1-knockout mice appeared normal. Expression patterns of several marker genes for cartilage, tendon, and muscle progenitors in homozygous mutant embryos were unchanged. These results suggest that Irxl1 is required for the tendon differentiation but dispensable for the patterning of the musculoskeletal system in development.     

The PE-PPE domain in mycobacterium reveals a serine α/β hydrolase fold and function: an in-silico analysis

The PE and PPE proteins first reported in the genome sequence of Mycobacterium tuberculosis strain H37Rv are now identified in all mycobacterial species. The PE-PPE domain (Pfam ID: PF08237) is a 225 amino acid residue conserved region located towards the C-terminus of some PE and PPE proteins and hypothetical proteins. Our in-silico sequence analysis revealed that this domain is present in all Mycobacteria, some Rhodococcus and Nocardia farcinica genomes. This domain comprises a pentapeptide sequence motif GxSxG/S at the N-terminus and conserved amino acid residues Ser, Asp and His that constitute a catalytic triad characteristic of lipase, esterase and cutinase activity. The fold prediction and comparative modeling of the 3-D structure of the PE-PPE domain revealed a "serine α/β hydrolase" structure with a central β-sheet flanked by α-helices on either side. The structure comprises a lid insertion with a closed structure conformation and has a solvent inaccessible active site. The oxyanion hole that stabilizes the negative charge on the tetrahedral intermediate has been identified. Our findings add to the growing list of serine hydrolases in mycobacterium, which are essential for the maintenance of their impermeable cell wall and virulence. These results provide the directions for the design of experiments to establish the function of PE and PPE proteins.     

Validation of the ALS assay in adult patients with culture confirmed pulmonary tuberculosis

Background

We have earlier shown that Bacille Calmette-Guérin (BCG) vaccine-specific IgG Antibodies in Lymphocyte Supernatant (ALS) can be used for diagnosis of active tuberculosis (TB) in adults and children.

Methodology/Principal Findings

The ALS method was validated in a larger cohort (n = 212) of patients with suspicion of pulmonary TB using multiple antigens (BCG, LAM, TB15.3, TB51A, CFP10-ESAT6-A, CFP, CW) from Mycobacterium tuberculosis. The sensitivity and specificity of the ALS assay was calculated using non-TB patients as controls. The sensitivity and the specificity were highest with BCG vaccine (90% and 88% respectively) followed by LAM (89% and 87% respectively). Simultaneous assessment of multiple antigen-specific antibodies increased sensitivity (91%) and specificity (88%). Using higher lymphocyte count in smaller volume of culture media increased detection and reduced the assay duration to ∼30 hrs. Twenty one patients with clinical findings strongly suggestive of TB finally diagnosed as non-TB patients were positive by the ALS assay, of which 9 (43%) were positive for 7 antigens and 19 (90%) for at least 3 antigens.

Conclusions/Significance

Our findings show that simultaneous detection of antigens improves the diagnostic potential of the ALS assay; the modified method increases sensitivity and can provide results in <48 hours, and enable detection of some cases of pulmonary TB that are not detectable by standard methods.     

Bacterial Communities in Bangladesh Aquifers Differing in Aqueous Arsenic Concentration

At Titas, Bangladesh, two aquifers of different arsenic concentrations and redox conditions were investigated to link variations in geochemistry to in situ bacterial diversity characterized by T-RFLP (terminal restriction fragment length polymorphism) and clone library analysis. While the shallow aquifer was characterized by reduced gray sediments with a higher share of easily mobilized sedimentary arsenic (2.6% was easily mobilized from 18 mg/kg of total arsenic available in sediments) and higher aqueous arsenic concentrations of 120 ± 6 μg/L (45% arsenite), the deeper aquifer consisted of brown oxidized sediments with lower aqueous arsenic concentrations, predominantly as arsenate (60 ± 6 μg/L; 3% arsenite) and a higher share of tightly bound arsenic (only 0.6% of 53 mg/kg total sorbed arsenic was easily mobilized). The bacterial communities of both aquifers were dominated by putative aerobic or denitrifying populations of Pseudomonas, Elizabethkingia and Pantoea. The shallow aquifer was more diverse in bacterial populations of aerobic, facultative and anaerobic bacteria, an observation which may be correlated to more variable geochemical conditions resulting in arsenic mobilization and re-sorption. The deeper aquifer showed higher abundance of aerobic bacterial populations including the presence of iron-oxidizing Sideroxydans possibly of importance for the sorption of arsenic on oxidized iron hydroxides. From the arsenic-affected shallow aquifer, As(III) oxidizing isolates of Comamonas and Microbacterium were obtained, which may provide information on suitable conditions for arsenic immobilization useful for future bioremediation efforts. Supplemental materials are available for this article. Go to the publisher’s online edition of Geomicrobiology Journal to view the free supplemental file.     

Chilli rhizosphere fungus Aspergillus spp. PPA1 promotes vegetative growth of cucumber (Cucumis sativus) plants upon root colonisation

A rhizosphere fungus was isolated from roots of chilli plants and identified as Aspergillus spp. PPA1. The fungus was tested for its ability to promote the growth of cucumber plants in a pot experiment. Cucumber seeds were sown in sterilised field soil amended with wheat grain inoculum (WGI) of PPA 1 at the rate of 0.5, 1 and 1.5% w/w, and plants were grown for 21 days in a net house. The treatment with PPA1 significantly increased shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, plant length, leaf area and leaf chlorophyll content of cucumber plants compared to non-treated control. The growth promotion rate increased with the increasing concentration of inoculum of PPA1 applied to the soil. The fungus was re-isolated from the roots of cucumber plants at higher frequencies. These results suggest that Aspergillus spp. PPA1 is a root colonising plant-growth promoting fungus for cucumber.