Biology subjects

Khan, M. S.

Publications and source records attributed to Khan, M. S..

33 records · Page 2Linked to original sources

bioRxiv2023

Efficient ultrasound-mediated drug delivery to orthotopic liver tumors: Direct comparison of doxorubicin-loaded nanobubbles and microbubbles

Liver metastasis is a major obstacle in treating aggressive cancers, and current therapeutic options often prove insufficient. To overcome these challenges, there has been growing interest in ultrasound-mediated drug delivery using lipid-shelled microbubbles (MBs) and nanobubbles (NBs) as promising strategies for enhancing drug delivery to tumors. Our previous work demonstrated the potential of Doxorubicin-loaded C3F8 NBs (hDox-NB, 280 {+/-} 123 nm) in improving cancer treatment in vitro using low-frequency ultrasound. In this study, we investigated the pharmacokinetics and biodistribution of sonicated hDox-NBs in orthotopic rat liver tumors. We compared their delivery and therapeutic efficiency with size-isolated MBs (hDox-MB, 1104 {+/-} 373 nm). Results showed a similar accumulation of hDox in tumors treated with hDox-MBs and unfocused therapeutic ultrasound (hDox-MB+TUS) and hDox-NB+TUS. However, significantly increased apoptotic cell death in the tumor and fewer off-target apoptotic cells in the normal liver were found upon the treatment with hDox-NB+TUS. The tumor-to-liver apoptotic ratio was elevated 9.4-fold following treatment with hDox-NB+TUS compared to hDox-MB+TUS, suggesting that the therapeutic efficacy and specificity are significantly increased when using hDox-NB+TUS. These findings highlight the potential of this approach as a viable treatment modality for liver tumors. By elucidating the behavior of drug-loaded bubbles in vivo, we aim to contribute to developing more effective liver cancer treatments that could ultimately improve patient outcomes and decrease off-target side effects.

bioengineering↗

bioRxiv2023

Tetravalent SARS-CoV-2 S1 Subunit Protein Vaccination Elicits Robust Humoral and Cellular Immune Responses in SIV-Infected Rhesus Macaque Controllers

The COVID-19 pandemic has highlighted the need for safe and effective vaccines to be rapidly developed and distributed worldwide, especially considering the emergence of new SARS-CoV-2 variants. Protein subunit vaccines have emerged as a promising approach due to their proven safety record and ability to elicit robust immune responses. In this study, we evaluated the immunogenicity and efficacy of an adjuvanted tetravalent S1 subunit protein COVID-19 vaccine candidate composed of the Wuhan, B.1.1.7 variant, B.1.351 variant, and P.1 variant spike proteins in a nonhuman primate model with controlled SIVsab infection. The vaccine candidate induced both humoral and cellular immune responses, with T- and B cell responses mainly peaking post-boost immunization. The vaccine also elicited neutralizing and cross-reactive antibodies, ACE2 blocking antibodies, and T-cell responses, including spike specific CD4+ T cells. Importantly, the vaccine candidate was able to generate Omicron variant spike binding and ACE2 blocking antibodies without specifically vaccinating with Omicron, suggesting potential broad protection against emerging variants. The tetravalent composition of the vaccine candidate has significant implications for COVID-19 vaccine development and implementation, providing broad antibody responses against numerous SARS-CoV-2 variants.

immunology↗

bioRxiv2022

A practical bacterial biodosimetry procedure to assess performance of lab-scale flow-through ultraviolet water disinfection reactors

Biodosimetry can be used to estimate the fluence of a reactor by determining its ability to inactivate a challenge organism. Especially for small-scale flow-through reactors, inconsistent procedures are reported for bacterial cells. This study aims to develop a standardized, simple procedure for bacterial biodosimetry in flow-through UV systems with relevant biofilm forming bacteria in order to evaluate biofouling control by UV. In particular, the challenge organism, the type of experimental setup and the execution of single steps during biodosimetry with bacterial cells can cause largely deviating results. Since previous work was restricted to model organism, which are not relevant for biofouling, we critically reevaluated all reported steps for the biofilm forming Aquabacterium citratiphilum and identified three main factors for biodosimetry reproducibility in flow-through systems: Protractions of cells from negative controls can heavily impact inactivation efficacy, but can be reduced by ordering samples by decreasing fluence. Further, to avoid photo repair, samples must be processed under red light only. Lastly, biofilm forming bacteria can strongly absorb on plastic labware, which requires counter measures in form of special labware and the addition of surfactants. Overall, the developed protocol provides a biodosimetry standardization for bacterial cells of flow-through systems, facilitating reproducibility and transferability of results between studies that use bacterial cells as challenge organism. SynopsisBiodosimetry is used to characterize performance of flow-through ultraviolet reactors, but artifacts can occur if not addressed properly.

microbiology↗

bioRxiv2022

Trivalent SARS-CoV-2 S1 Subunit Protein Vaccination Induces Broad Humoral Responses in BALB/c Mice

This paper presents a novel approach for improving the efficacy of COVID-19 vaccines against emergent SARS-CoV-2 variants. We have evaluated the immunogenicity of unadjuvanted wild-type (WU S1-RS09cg) and variant-specific (Delta S1-RS09cg and OM S1-RS09cg) S1 subunit protein vaccines delivered either as a monovalent or a trivalent antigen in BALB/c mice. Our results show that a trivalent approach induced a broader humoral response with more coverage against antigenically distinct variants, especially when compared to monovalent Omicron-specific S1. This trivalent approach was also found to have increased or equivalent ACE2 binding inhibition, and increased S1 IgG endpoint titer at early timepoints, against SARS-CoV-2 spike variants when compared monovalent Wuhan, Delta, or Omicron S1. Our results demonstrate the utility of protein subunit vaccines against COVID-19 and provide insights into the impact of variant-specific COVID-19 vaccine approaches on the immune response in the current SARS-CoV-2 variant landscape. Particularly, our study provides insight into effects of further increasing valency of currently approved SARS-CoV-2 vaccines, a promising approach for improving protection to curtail emerging viral variants.

immunology↗

bioRxiv2022

Comparative Phylogenetic Analysis and Transcriptomic Profiling of Dengue (DENV-3 genotype I) Outbreak in 2021 in Bangladesh

ObjectivesThe lack of a dengue disease animal model and the complex immune interaction in dengue infection hinders the study of host response and immunopathogenesis. The development of next-generation sequencing (NGS) technology allowed the researchers to study the transcriptomic profiles of human in-depth. We, therefore, implicated phylodynamic and transcriptomic approaches through NGS technology to know the origin of dengue virus (DENV) and their host response in infected patients with dengue fever. MethodsTo determine the whole genome sequences of the dengue virus and their transcriptomic profiles, RNA was extracted from the serum samples of 3 healthy, and 21 dengue patients. These samples were custom performed at phylogenetic, phylodynamic, differential express gene (DEG), and gene ontology (GO) using respective bioinformatics tools. ResultsThe whole genome sequence analysis revealed that the total number of nucleotide ranges on these serum RNA samples were in between 10647 and 10707. Phylogenetic tree analysis showed that these strains were belonged to DENV-3 genotype I. Phylodynamic analysis showed that the 2021 epidemic isolates were clade shifted and maintained as a new clade in compared to 2019 epidemic. Transcriptome analysis mapped a total of 19267 expressed genes. Of them, there were higher expression of genes in dengue-positive samples (n = 17375) with a count of 6953 unique genes in comparison to healthy controls (n = 12314) with a count of 1892 unique genes. A total of 2686 DEGs were identified in a host factor-independent manner in dengue patients with a q-value < 0.05. DESeq2 plot counts function of the top 24 genes with the smallest q-values of differential gene expression of RNA-seq data showed that 11 genes were upregulated, whereas 13 genes were downregulated. GO analysis showed a significant upregulation (p = <0.001) in a process of multicellular organismal, nervous system, sensory perception of chemical stimulus, and G protein-coupled receptor signalling pathways in the dengue patients. However, there were a significant downregulation (p = < 0.001) of intracellular component, cellular anatomical entity, and protein-containing complex in dengue patients. Most importantly, there was significant increase of a classes of immunity protein (Cytokines especially TGF-{beta}1, chemokines, inflammasome, and factors for blood coagulations) in dengue patients in compared to the healthy controls, with increased GO of immune system process. In addition, upregulation of toll receptor (TLR) signalling pathways were also initiated in the patients infected with dengue virus. These TLR pathways were particularly involved for the activation of innate in couple with adaptive immune system that probably involved the rapid elimination of dengue virus infected cells. These differentially expressed genes could be further investigated for target based prophylactic interventions for dengue. ConclusionThis is a first report to document the complete genomic features of dengue, and differentially expressed genes in patients with dengue virus in Bangladesh. These genes may have diagnostic and therapeutic values for dengue infection. Continual genomic surveillance is required to further investigate the shift in dominant genotypes in relation to viral pathogenesis.

evolutionary biology↗

bioRxiv2022

SARS-CoV-2 S1 Subunit Booster Vaccination Elicits Robust Humoral Immune Responses in Aged Mice

Currently approved COVID-19 vaccines prevent symptomatic infection, hospitalization, and death of the disease. However, the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants raises concerns of reduced vaccine effectiveness and increased risk of infection. Repeated homologous booster in elderly individuals and immunocompromised patients is considered to solve severe form of disease caused by new SARS-CoV-2 variants but cannot protect completely against breakthrough infection. In our previous study we assessed the immunogenicity of an adenovirus-based vaccine expressing SARS-CoV-2-S1 (Ad5.S1) in mice, resulting in that a single immunization with Ad5.S1, via subcutaneously injection or intranasal delivery, induced robust humoral and cellular immune responses [1]. As a follow up study, here we showed that vaccinated mice had high titers of anti-S1 antibodies at one year after vaccination compared to PBS immunized mice. Furthermore, one booster dose of non-adjuvanted recombinant S1Beta (rS1Beta) subunit vaccine was effective in stimulating strong long-lived S1-specific immune responses and inducing significantly high neutralizing antibodies against the Wuhan, Beta, and Delta strain with 3.6- to 19.5-fold change increases. Importantly, the booster dose elicits cross-reactive antibody responses resulting in ACE2 binding inhibition against spike of SARS-CoV-2 variants (Wuhan, Alpha, Beta, Gamma, Delta, Zeta, Kappa, New York, India) as early as two-week post-boost injection, persisting over 28 weeks after a booster vaccination. Interestingly, levels of neutralizing antibodies were correlated with not only level of S1-binding IgG but also level of ACE2 inhibition in the before- and after-booster serum samples. Our findings show that S1 recombinant protein subunit vaccine candidate as a booster has potential to offer cross-neutralization against broad variants, and has important implications for vaccine control of new emerging breakthrough SARS-CoV-2 variants in elderly individuals primed with adenovirus-based vaccine like AZD1222 and Ad26.COV2.S.

microbiology↗

bioRxiv2022

A Canine Model of Chronic Ischemic Heart Failure

BackgroundThere is a paucity of novel therapeutics for chronic heart failure (HF). Preclinical large animal models of chronic HF are crucial to translating fundamental discoveries. Canine models of ischemic cardiomyopathy are frequently utilized but are severely limited by competing needs to both induce sufficient muscle injury which results in an appropriately severe degree of left ventricular dysfunction yet to also minimize early mortality. MethodsTwenty-eight healthy adult dogs (30{+/-}4 kg, 15/28 male) underwent thoracotomy procedures followed by one of three types of left anterior descending (LAD) coronary artery ligations: Simple LAD (proximal and distal LAD ligation), LAD and Lateral (proximal and distal LAD, distal first diagonal, and proximal first obtuse marginal), and Total LAD Devascularization (TLD including the proximal and distal LAD, proximal aspects of the first, second, and third diagonals, and proximal aspects of first and second epicardial right ventricular branches of the LAD). Invasive and non-invasive hemodynamics were followed until attainment of chronic severe HF, which was achieved when left ventricular ejection fraction (LVEF) was <40% and N-terminal prohormone B-type Natriuretic peptide (NT-proBNP) >900 pmol/L, both for two consecutive measurements. ResultsOverall post-ligation early mortality (within 48 h of coronary ligation) was 18% (n=5/28), and the overall survival rate at 5 weeks post-ligation was 68% (n=19/28). At post-ligation week 1, LVEF was acutely reduced in all animals, from 54{+/-}4 to 38{+/-}1%, p<0.001. Beyond week 1, systolic function recovered over 3-4 weeks and then slowly declined as the left ventricle dilated and both systolic and diastolic function worsened. The magnitude of the initial decline in LVEF predicted ultimate HF development. Dogs with Simple LAD and LAD plus Lateral had excellent and limited survival at 48 hours (100% and 47%, respectively), yet the second group more likely developed chronic HF at 9 - 14 weeks (50% versus 57%, respectively). Dogs with TLD had both improved survival at 48 hours (90%) and excellent development of chronic HF (100%). ConclusionsBy focusing on the LAD only and limiting collateral flow to it by ligating all side branches, optimal survival and attainment of chronic ischemic HF can be achieved in the canine heart.

developmental biology↗

bioRxiv2022

Adenovirus-Vectored SARS-CoV-2 Vaccine Expressing S1-N Fusion Protein

Additional COVID-19 vaccines that are safe, easy to manufacture, and immunogenic are needed for global vaccine equity. Here, we developed a recombinant type 5 adenovirus vector encoding for the SARS-CoV-2-S1 subunit antigen and nucleocapsid as a fusion protein (Ad5.SARS-CoV-2-S1N) delivered to BALB/c mice through multiple vaccine administration routes. A single subcutaneous (S.C.) immunization with Ad5.SARS-CoV-2-S1N induced a similar humoral response, along with a significantly higher S1-specific cellular response, as a recombinant type 5 adenovirus vector encoding for S1 alone (Ad5.SARS-CoV-2-S1). Immunogenicity was improved by homologous prime boost strategies, using either S.C. or intranasal (I.N.) delivery of Ad5.SARS-CoV-2-S1N, and further improved through heterologous prime boost, with traditional intramuscular (I.M.) injection, using subunit recombinant S1 protein. Priming with low dose (1x1010 v.p.) of Ad5.SARS-CoV-2-S1N and boosting with either wildtype recombinant rS1 or B.1.351 recombinant rS1 induced a robust neutralizing response, that was sustained against immune evasive Beta and Gamma SARS-CoV-2 variants, along with a long-lived plasma cell response in the bone marrow 29 weeks post vaccination. This novel Ad5-vectored SARS-CoV-2 vaccine candidate showed promising immunogenicity in mice and supports the further development of COVID-19 based vaccines incorporating the nucleoprotein as a target antigen.

immunology↗

bioRxiv2022

Highly Thermotolerant SARS-CoV-2 Vaccine Elicits Neutralising Antibodies Against Delta and Omicron in Mice

As existing vaccines fail to completely prevent COVID-19 infections or community transmission, there is an unmet need for vaccines that can better combat SARS-CoV-2 variants of concern (VOC). We have previously developed highly thermo-tolerant monomeric and trimeric receptor binding domain derivatives that can withstand 100{degrees}C for 90 minutes and 37{degrees}C for four weeks, and help eliminate cold chain requirements. We show that mice immunised with these vaccine formulations elicit high titres of antibodies that neutralise SARS-CoV-2 variants VIC31 (with Spike: D614G mutation), Delta and Omicron (BA.1.1) VOC. Compared to VIC31, there was an average 14.4-fold reduction in neutralisation against BA.1.1 for the three monomeric antigen-adjuvant combinations, and 16.5-fold reduction for the three trimeric antigen-adjuvant combinations; the corresponding values against Delta were 2.5 and 3.0. Our findings suggest that monomeric formulations are suitable for the upcoming Phase I human clinical trials, and that there is potential for increasing efficacy with vaccine matching to improve responses against emerging variants. These findings are consistent with in silico modelling and AlphaFold predictions which show that while oligomeric presentation can be generally beneficial, it can make important epitopes inaccessible, and also carries the risk of eliciting unwanted antibodies against the oligomerisation domain.

immunology↗

bioRxiv2022

Metagenomic analysis reveals the abundance and diversity of opportunistic fungal pathogens in the nasopharyngeal tract of COVID-19 patients

The nasopharyngeal tract (NT) of human is a habitat of a diverse microbial community that work together with other gut microbes to maintain the host immunity. In our previous study, we reported that SARS-CoV-2 infection reduces human nasopharyngeal commensal microbiome (bacteria, archaea and commensal respiratory viruses) but increases the abundance of pathobionts. This study aimed to assess the possible changes in the resident fungal diversity by the inclusion of opportunistic fungi due to the infection of SARS-CoV-2 in the NT of humans. Twenty-two (n = 22) nasopharyngeal swab samples (including COVID-19 = 8, Recovered = 7, and Healthy = 7) were collected for RNAseq-based metagenomics analyses. Our results indicate that SARS-CoV-2 infection significantly increased (p < 0.05, Wilcoxon test) the population and diversity of NT fungi with a high inclusion of opportunistic pathogens. We detected 863 fungal species including 533, 445, and 188 species in COVID-19, Recovered, and Healthy individuals, respectively that indicate a distinct microbiome dysbiosis due to the SARS-CoV-2 infection. Remarkably, 37% of the fungal species were exclusively associated with SARS-CoV-2 infection, where S. cerevisiae (88.62%) and Phaffia rhodozyma (10.30%) were two top abundant species in the NT of COVID-19 patients. Importantly, 16% commensal fungal species found in the Healthy control were not detected in either COVID-19 patients or when they were recovered from the COVID-19. Pairwise Spearmans correlation test showed that several altered metabolic pathways had significant positive correlations (r > 0.5, p < 0.01) with dominant fungal species detected in three metagenomes. Taken together, our results indicate that SARS-CoV-2 infection causes significant dysbiosis of fungal microbiome and alters some metabolic pathways and expression of genes in the NT of human. Findings of our study might be helpful for developing microbiome-based diagnostics, and also devising appropriate therapeutic regimens including antifungal drugs for prevention and control of concurrent fungal coinfections in COVID-19 patients. Author summaryThe SARS-CoV-2 is a highly transmissible and pathogenic betacoronavirus that primarily enters into the human body through NT to cause fearsome COVID-19 disease. Recent high throughput sequencing and downstream bioinformatic analyses revealed that microbiome dysbiosis associated with SARS-CoV-2 infection are not limited to bacteria, and fungi are also implicated in COVID-19 development in susceptible individuals. This study demonstrates that SARS-CoV-2 infection results in remarkable depletion of NT commensal fungal microbiomes with inclusion of various opportunistic fungal pathogens. We discussed the role of these altered fungal microbiomes in the pathophysiology of the SARS-CoV-2 infection. Our results suggest that dysbiosis in fungal microbiomes and associated altered metabolic functional pathways (or genes) possibly play a determining role in the progression of SARS-CoV-2 pathogenesis. Thus, the identifiable changes in the diversity and composition of the NT fungal population and their related genomic features demonstrated in this study might lay a foundation for better understanding of the underlying mechanism of co-pathogenesis, and the ongoing development of therapeutic agents including antifungal drugs for the resolution of COVID-19 pandemic.

microbiology↗

bioRxiv2021

Characterization and Structural Prediction of ORF10, ORF7b, ORF7a, ORF6, Membrane Glycoprotein, and Envelope Protein in SARS-CoV-2 Bangladeshi Variant through Bioinformatics Approach

The acute respiratory disease induced by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has become a global epidemic in just less than a year by the first half of 2020. The subsequent efficient human-to-human transmission of this virus eventually affected millions of people worldwide. The most devastating thing is that the infection rate is continuously uprising and resulting in significant mortality especially among the older age population and those with health co-morbidities. This enveloped, positive-sense RNA virus is chiefly responsible for the infection of the upper respiratory system. The virulence of the SARS-CoV-2 is mostly regulated by its proteins like entry to the host cell through fusion mechanism, fusion of infected cells with neighboring uninfected cells to spread the virus, inhibition of host gene expression, cellular differentiation, apoptosis, mitochondrial biogenesis, etc. But very little is known about the protein structures and functionalities. Therefore, the main purpose of this study is to learn more about these proteins through bioinformatics approaches. In this study, ORF10, ORF7b, ORF7a, ORF6, membrane glycoprotein, and envelope protein have been selected from a Bangladeshi Corona-virus strain G039392 and a number of bioinformatics tools (MEGA-X-V10.1.7, PONDR(R), ProtScale, ProtParam, SCRIBER, NetSurfP v2.0, IntFOLD, UCSF Chimera, and PyMol) and strategies were implemented for multiple sequence alignment and phylogeny analysis with 9 different variants, predicting hydropathicity, amino acid compositions, protein-binding propensity, protein disorders, 2D and 3D protein modeling. Selected proteins were characterized as highly flexible, structurally and electrostatically extremely stable, ordered, biologically active, hydrophobic, and closely related to the proteins of different variants. This detailed information regarding the characterization and structure of proteins of SARS-CoV-2 Bangladeshi variant was performed for the first time ever to unveil the deep mechanism behind the virulence features and also, this robust appraisal paves the future way for molecular docking, vaccine development targeting these characterized proteins.

bioinformatics↗

bioRxiv2021

A highly thermotolerant, trimeric SARS-CoV-2 receptor binding domain derivative elicits high titers of neutralizing antibodies

The Receptor Binding Domain (RBD) of SARS-CoV-2 is the primary target of neutralizing antibodies. We designed a trimeric, highly thermotolerant glycan engineered RBD by fusion to a heterologous, poorly immunogenic disulfide linked trimerization domain derived from cartilage matrix protein. The protein expressed at a yield of [~]80-100 mg/liter in transiently transfected Expi293 cells, as well as CHO and HEK293 stable cell lines and formed homogeneous disulfide-linked trimers. When lyophilized, these possessed remarkable functional stability to transient thermal stress of upto 100 {degrees}C and were stable to long term storage of over 4 weeks at 37 {degrees}C unlike an alternative RBD-trimer with a different trimerization domain. Two intramuscular immunizations with a human-compatible SWE adjuvanted formulation, elicited antibodies with pseudoviral neutralizing titers in guinea pigs and mice that were 25-250 fold higher than corresponding values in human convalescent sera. Against the beta (B.1.351) variant of concern (VOC), pseudoviral neutralization titers for RBD trimer were [~] three-fold lower than against wildtype B.1 virus. RBD was also displayed on a designed ferritin-like Msdps2 nanoparticle. This showed decreased yield and immunogenicity relative to trimeric RBD. Replicative virus neutralization assays using mouse sera demonstrated that antibodies induced by the trimers neutralized all four VOC to date, namely B.1.1.7, B.1.351, P.1 and B.1.617.2 without significant differences. Trimeric RBD immunized hamsters were protected from viral challenge. The excellent immunogenicity, thermotolerance, and high yield of these immunogens suggest that they are a promising modality to combat COVID-19, including all SARS-CoV-2 VOC to date.

microbiology↗

bioRxiv2020

Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment

Virtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Several use viral vectors or mRNA. In contrast to protein subunit vaccines, there is limited manufacturing expertise for these novel, nucleic acid based modalities, especially in the developing world. Neutralizing antibodies, the clearest known correlate of protection against SARS-CoV-2, are primarily directed against the Receptor Binding Domain (RBD) of the viral spike protein. We describe a monomeric, glycan engineered RBD protein fragment that is expressed at a purified yield of 214mg/L in unoptimized, mammalian cell culture and in contrast to a stabilized spike ectodomain, is tolerant of exposure to temperatures as high as 100{degrees}C when lyophilized, upto 70{degrees}C in solution and stable for over four weeks at 37{degrees}C. In prime:boost guinea pig immunizations, when formulated with the MF59 like adjuvant AddaVax, the RBD derivative elicited neutralizing antibodies with an endpoint geometric mean titer of ~415 against replicative virus, comparing favourably with several vaccine formulations currently in the clinic. These features of high yield, extreme thermotolerance and satisfactory immunogenicity suggest that such RBD subunit vaccine formulations hold great promise to combat COVID-19.

biophysics↗

bioRxiv2020

The genetic variants analysis of circulating SARS-CoV-2 in Bangladesh.

Genomic mutation of the virus may impact the viral adaptation to the local environment, their transmission, disease manifestation, and the effectiveness of existing treatment and vaccination. The objectives of this study were to characterize genomic variations, non-synonymous amino acid substitutions, especially in target proteins, mutation events per samples, mutation rate, and overall scenario of coronaviruses across the country. To investigate the genetic diversity, a total of 184 genomes of virus strains sampled from different divisions of Bangladesh with sampling dates between the 10th of May 2020 and the 27th of June 2020 were analyzed. To date, a total of 634 mutations located along the entire genome resulting in non-synonymous 274 amino acid substitutions in 22 different proteins were detected with nucleotide mutation rate estimated to be 23.715 substitutions per year. The highest non-synonymous amino acid substitutions were observed at 48 different positions of the papain-like protease (nsp3). Although no mutations were found in nsp7, nsp9, nsp10, and nsp11, yet orf1ab accounts for 56% of total mutations. Among the structural proteins, the highest non-synonymous amino acid substitution (at 36 positions) observed in spike proteins, in which 9 unique locations were detected relative to the global strains, including 516E>Q in the boundary of the ACE2 binding region. The most dominated variant G614 (95%) based in spike protein is circulating across the country with co-evolving other variants including L323 (94%) in RNA dependent RNA polymerase (RdRp), K203 (82%) and R204 (82%) in nucleocapsid, and F120 (78%) in NSP2. These variants are mostly seen as linked mutations and are part of a haplotype observed in Europe. Data suggest effective containment of clade G strains (4.8%) with sub-clusters GR 82.4%, and GH clade 6.4%. HighlightsO_LIWe have sequenced 137 and analyzed 184 whole-genomes sequences of SARS-CoV-2 strains from different divisions of Bangladesh. C_LIO_LIA total of 634 mutation sites across the SARS-CoV-2 genome and 274 non-synonymous amino acid substitutions were detected. C_LIO_LIThe mutation rate of SARS-CoV-2 estimated to be 23.715 nucleotide substitutions per year. C_LIO_LINine unique variants were detected based on non-anonymous amino acid substitutions in spike protein relative to the global SARS-CoV-2 strains. C_LI

genomics↗

bioRxiv2019

Establishing BARA: Biological Nitrogen Fixation for Future Agriculture

The extensive use of nitrogen (N) fertilizers implicates a paradox. While fertilizers ensure the supply of a large amount of food, they cause negative environmental externalities including reduced biodiversity, eutrophic streams, and lakes. Moreover, such fertilizers may also result in a major public health hazard: increased antibiotic resistance. This Perspective discusses a critical role of perturbations in N cycle caused by excessive use of fertilizers and resulting implications as they relate to resistance genes and biodiversity in the biosphere. While there are solutions such as cover crops, these solutions are expensive and inconvenient for farmers. We advocate the use of biological fixation for staple crops--microbiome mediated natural supply of fixed N. This would involve engineering a microbiome that can be grown cheaply and at scale (less expensive than Haber-Bosch fertilizers). We also propose a practical framework of where and how research investments should be directed to make such a solution practical. We make three recommendations for decision makers to facilitate a successful trajectory for this solution. First, that future agricultural science seek to understand how biological fixation might be employed as a practical and efficient strategy. This effort would require that industries and government partner to establish a pre-competitive research laboratory equipped with the latest state-of-the-art technologies that conduct metagenomic experiments to reveal signature microbiomes. Second, the Department of Agriculture and state governments provide research and development (R & D) tax credits to biotech companies specifically geared towards R&D investments aimed at increasing the viability of biological fixation and microbiome engineering. Third, governments and the UN Food and Agriculture Organization (FAO) coordinate Biological Advanced Research in Agriculture (BARA)--a global agricultural innovation initiative for investments and research in biological fixation and ethical, legal, and social implications of such innovation.

microbiology↗