Biology subjects

Kang, G.

Publications and source records attributed to Kang, G..

31 records · Page 2Linked to original sources

bioRxiv2023

Recent emergence of cephalosporin resistant Salmonella Typhi carrying IncFIB(K) plasmid encoding blaCTX-M-15 gene in India

The emergence and spread of Salmonella Typhi (S. Typhi) resistant to third-generation cephalosporins is a serious global health concern. In this study, we genomically characterized 142 cephalosporin-resistant S. Typhi strains isolated from India. Comparative genome analysis revealed the emergence of a new clone of ceftriaxone-resistant S. Typhi harboring three plasmids of the incompatibility groups IncFIB(K), IncX1, and IncFIB(pHCM2). Among these, the IncFIB(K) plasmid confers resistance to third-generation cephalosporins through the blaCTX-M-15 gene, along with other resistance determinants such as aph(3"), aph(6), sul2, dfrA14, qnrS, and tetA. Phylogenetic analysis showed that the isolates from Gujarat (n=140/142) belong to a distinct subclade (genotype 4.3.1.2.2) within genotype 4.3.1.2 (H58 lineage II). SNP-based phylogenetic analysis of the core genes in IncFIB(K) reveals a close genetic relationship between the plasmid backbone and that of IncFIB(K) from other Enterobacterales, suggesting that the H58 lineage II possesses the capability to acquire MDR plasmids from these organisms. This could indicate the potential onset of a new wave of ceftriaxone-resistant S. Typhi in India. The implementation of control measures such as vaccination, and improved water, sanitation, and hygiene (WASH) systems, is crucial in areas where MDR or XDR S. Typhi strains are prevalent to curb the spread and impact of these resistant strains. ImportanceTyphoid fever remains a significant public health problem in many parts of the world, particularly in resource-limited settings with inadequate sanitation and limited access to clean water. The emergence of MDR S. Typhi resistant to first-line antibiotics (chloramphenicol, ampicillin, and cotrimoxazole) and fluoroquinolones marked the initial treatment challenge, leading to reliance on azithromycin and third-generation cephalosporins. Recently, researchers identified the emergence of XDR typhoid in Pakistan that is resistant to five classes of antibiotics including third-generation cephalosporins. In this study, we report a recent emergence of S. Typhi isolates resistant to third-generation cephalosporins. Genomic characterization and evolutionary analysis of the new strains revealed a recent acquisition of blaCTX-M carrying IncFIB(K) plasmid led to the emergence of ceftriaxone-resistant S. Typhi. Due to the ongoing nature of this outbreak, the data from this study deserves further consideration in order to control its spread in India.

genomics↗

bioRxiv2023

Structural alterations in the amygdala and impaired social incentive learning in a mouse model of a genetic variant associated with neurodevelopmental disorders

Copy number variants (CNVs) are robustly associated with psychiatric disorders and their dimensions and changes in brain structures and behavior. However, as CNVs contain many genes, the precise gene-phenotype relationship remains unclear. Although various volumetric alterations in the brains of 22q11.2 CNV carriers have been identified in humans and mouse models, it is unknown how the genes in the 22q11.2 region individually contribute to structural alterations and associated mental illnesses and their dimensions. Our previous studies have identified Tbx1, a T-box family transcription factor encoded in 22q11.2 CNV, as a driver gene for social interaction and communication, spatial and working memory, and cognitive flexibility. However, it remains unclear how TBX1 impacts the volumes of various brain regions and their functionally linked behavioral dimensions. In this study, we used volumetric magnetic resonance imaging analysis to comprehensively evaluate brain region volumes in congenic Tbx1 heterozygous mice. Our data show that the volumes of anterior and posterior portions of the amygdaloid complex and its surrounding cortical regions were reduced in Tbx1 heterozygous mice. Moreover, we examined the behavioral consequences of an altered volume of the amygdala. Tbx1 heterozygous mice were impaired for their ability to detect the incentive value of a social partner in a task that depends on the amygdala. Our findings identify the structural basis for a specific social dimension associated with loss-of-function variants of TBX1 and 22q11.2 CNV.

neuroscience↗

bioRxiv2022

Genomic analysis unveils the role of genome degradation events and gene flux in the emergence and persistence of S. Paratyphi A lineages

Paratyphoid fever caused by S. Paratyphi A is endemic in parts of Asia and Sub-Saharan Africa. The proportion of enteric fever cases caused by S. Paratyphi A has substantially increased, yet only limited data is available on the population structure and genetic diversity of this serovar. We examined the phylogenetic distribution and evolutionary trajectory of S. Paratyphi A isolates collected as part of the Indian enteric fever surveillance study "Surveillance of Enteric Fever in India (SEFI)." In the study period (2017-2020), S. Paratyphi A comprised 17.6% (441/2503) of total enteric fever cases in India, with the isolates highly susceptible to all the major antibiotics used for treatment except fluoroquinolones. Phylogenetic analysis clustered the global S. Paratyphi A collection into seven lineages (A-G), and the present study isolates were distributed in lineages A, C and F. Our analysis documented that the genome degradation events and gene acquisitions or losses play a major role in the evolution of new S. Paratyphi A lineages/sub-lineages. A total of 10 pseudogene-forming mutations possibly associated with the emergence of lineages were identified. Pan-genome analysis identified the insertion of P2/PSP3 phage and acquisition of IncX1 plasmid during the selection in 2.3.2/2.3.3 and 1.2.2 genotypes, respectively. We also identified that the six characteristic missense mutations associated with the lipopolysaccharide (LPS) biosynthesis genes of S. Paratyphi A confer only a low structural impact and would therefore have minimal impact on vaccine effectiveness. Since S. Paratyphi A is human restricted, high levels of genetic drift are not expected unless these bacteria transmit to naive hosts. However, public-health investigation and intervention by means of genomic surveillance would be continually needed to avoid S. Paratyphi A serovar becoming a public health threat similar to the S. Typhi of today.

genomics↗

bioRxiv2021

Transcriptional regulation of neonatal neural stem cells is a determinant of social behavior

Rare gene variants confer a high level of penetrance to neurodevelopmental disorders, but their developmental origin and cellular substrates remain poorly understood. To address this limitation, we explored the role of TBX1, a gene encoded in a rare copy number variant, in cell and mouse models. Here, we report that neonatal Tbx1 deficiency contributes to defective peripubertal social behavior and impairs the proliferation of neonatal neural stem/progenitor cells. Moreover, TBX1 transcriptionally regulates genes linked to post-embryonic neurogenesis and neurodevelopmental disorders associated with other rare gene variants. Our data indicate a precise time window and cell type through which the social dimension is altered by a gene encoded in a rare CNV and provide a potential common mechanistic basis for a group of neurodevelopmental disorders. One-Sentence SummaryTbx1, a gene affecting neonatal stem cell proliferation, influences peripubertal social behavior.

neuroscience↗

bioRxiv2021

Tbx1, a 22q11.2-encoded gene, is a link between alterations in fimbria myelination and cognitive speed in mice

Copy number variants (CNVs) have provided a reliable entry point to identify structural correlates of atypical cognitive development. Hemizygous deletion of human chromosome 22q11.2 is associated with impaired cognitive function; however, the mechanisms by which numerous genes encoded in this CNV contribute to cognitive deficits via diverse structural alterations in the brain remain unclear. This study aimed to determine the cellular basis of the link between alterations in brain structure and cognitive functions in a mouse model. The heterozygosity of Tbx1, a 22q11.2 gene, altered the composition of myelinated axons in the fimbria, reduced oligodendrocyte production capacity, and slowed the acquisition of spatial memory and cognitive flexibility. Our findings provide a cellular basis for specific cognitive dysfunctions that occur in patients with loss-of-function TBX1 variants and 22q11.2 hemizygous deletion. TeaserA risk gene for autism alters myelin composition in the hippocampal connection and slows cognitive speed.

neuroscience↗

bioRxiv2020

Evolutionary tracking of SARS-CoV-2 genetic variants highlights intricate balance of stabilizing and destabilizing mutations

The currently ongoing COVID-19 pandemic caused by SARS-CoV-2 has accounted for millions of infections and deaths across the globe. Genome sequences of SARS-CoV-2 are being published daily in public databases and the availability of this genome datasets has allowed unprecedented access into the mutational patterns of SARS-CoV-2 evolution. We made use of the same genomic information for conducting phylogenetic analysis and identifying lineage-specific mutations. The catalogued lineage defining mutations were analysed for their stabilizing or destabilizing impact on viral proteins. We recorded persistence of D614G, S477N, A222V V1176F variants and a global expansion of the PANGOLIN variant B.1. In addition, a retention of Q57H (B.1.X), R203K/G204R (B.1.1.X), T85I (B.1.2-B.1.3), G15S+T428I (C.X) and I120F (D.X) variations was observed. Overall, we recorded a striking balance between stabilizing and destabilizing mutations, therefore well-maintained protein structures. With selection pressures in the form of newly developed vaccines and therapeutics to mount soon in coming months, the task of mapping of viral mutations and recording of their impact on key viral proteins would be crucial to pre-emptively catch any escape mechanism that SARS-CoV-2 may evolve for. STUDY IMPORTANCEAs large numbers of the SARS CoV-2 genome sequences are shared in publicly accessible repositories, it enables scientists a detailed evolutionary analysis since its initial isolation in Wuhan, China. We investigated the evolutionarily associated mutational diversity overlaid on the major phylogenetic lineages circulating globally, using 513 representative genomes. We detailed phylogenetic persistence of key variants facilitating global expansion of the PANGOLIN variant B.1, including the recent, fast expanding, B.1.1.7 lineage. The stabilizing or destabilizing impact of the catalogued lineage defining mutations on viral proteins indicates their possible involvement in balancing the protein function and structure. A clear understanding of this mutational profile is of high clinical significance to catch any vaccine escape mechanism, as the same proteins make crucial components of vaccines recently approved and in development. In this direction, our study provides an imperative framework and baseline data upon which further analysis could be built as newer variants of SARS-CoV-2 continue to appear.

genomics↗

bioRxiv2020

Salmonella Typhi acquires diverse plasmids from other Enterobacteriaceae to develop cephalosporin resistance

BackgroundRecent reports have established the emergence and dissemination of extensively drug resistant (XDR) H58 Salmonella Typhi clone in Pakistan. In India where typhoid fever is endemic, only sporadic cases of ceftriaxone resistant S. Typhi are reported. This study aimed at elucidating the phylogenetic evolutionary framework of ceftriaxone resistant S. Typhi isolates from India to predict their potential dissemination in endemic regions. MethodsFive ceftriaxone resistant S. Typhi isolates from three tertiary care hospitals in India were sequenced on an Ion Torrent Personal Genome Machine (PGM). A core genome single-nucleotide-polymorphism (SNP) based phylogeny of the isolates in comparison to the global collection of MDR and XDR S. Typhi isolates was built. Two of five isolates were additionally sequenced using Oxford Nanopore MinION to completely characterize the plasmid and understand its transmission dynamics within Enterobacteriaceae. ResultsComparative genomic analysis and detailed plasmid characterization indicate that while in Pakistan (4.3.1 lineage I) the XDR trait is associated with blaCTX-M-15 gene on IncY plasmid, in India (4.3.1 lineage II), the ceftriaxone resistance is due to short term adaptation of resistance plasmids such as IncX3 or IncN. ConclusionSince the bacterial acquisition of smaller resistance plasmids such as IncX3 or IncN from other Enterobacteriaceae can be much faster than the larger IncY plasmids, the rapid expansion of these genotypically novel XDR S. Typhi could potentially cause large outbreaks. Therefore, continuous monitoring of S. Typhi lineages carrying cephalosporin resistance on IncX3 or IncN plasmids is vital not just for India but globally. ImportanceGenomic analysis of cephalosporin resistant S. Typhi isolated from India indicates the potential of S. Typhi to develop cephalosporin resistance by acquiring diverse plasmids from other Enterobacteriaceae. We identified the occurrence of independent acquisition of drug-resistant plasmids such as IncX3 and IncN with genes encoding beta-lactamases in H58/4.3.1.2 lineage. A short term adaptation of drug-resistant plasmids in H58/4.3.1.2 lineage can be the reason for the sporadic cases cephalosporin resistant S. Typhi in India. However, the IncY plasmid acquired by isolates that belong to H58/4.3.1.1 lineage appeared to be well adapted as observed in XDR S. Typhi outbreak in Pakistan. Plasmid acquisition and maintenance of cephalosporin resistant S. Typhi appears to be specific to the phylogenetic lineage as lineages differ in compensating the initial cost imposed by the plasmid. The stable maintenance of these resistance plasmids without a fitness cost, are determinant in understanding the future spread of cephalosporin resistance in S. Typhi. Therefore, critical strategies in monitoring and control of cephalosporin resistant S. Typhi is needed to tackle further public health crisis.

genomics↗

bioRxiv2020

Maternal approach behaviors toward neonatal calls are impaired by mother's experiences of raising pups with a risk gene variant for autism

How the intrinsic sequence structure of neonatal mouse pup ultrasonic vocalization (USV) and maternal experiences determine maternal behaviors in mice is poorly understood. Our previous work showed that pups with a Tbx1 heterozygous (HT) mutation, a genetic risk for autism spectrum disorder (ASD), emit altered call sequences that do not induce maternal approach behaviors in C57BL6/J mothers. Here, we tested how maternal approach behaviors induced by wild-type and HT USVs are influenced by the mothers experience in raising pups of these two genotypes. The results showed that wild-type USVs were effective in inducing maternal approach behaviors when mothers raised wild-type but not HT pups. The USVs of HT pups were ineffective regardless of whether mothers raised HT or wild-type pups. However, the sequence structure of pup USVs had no effect on the general, non-directional incentive motivation of maternal behaviors. Our data show how the mothers experience with a pup with a genetic risk for ASD alters the intrinsic incentive values of USV sequences in maternal approach behaviors.

developmental biology↗

bioRxiv2020

A sound strategy for homology modeling-based affinity maturation of a HIF-1α single-domain intrabody

A sound strategy for computer-aided binding affinity prediction was developed for in silico nanobody affinity maturation. Venn-intersection of multi-algorithm screening (VIMAS), an iterative computer-assisted nanobody affinity maturation virtual screening procedure, was designed. Homology modeling and protein docking methods were used to substitute the need for solution of a complex crystal structure, which is expanding the application of this platform. As a test case, an anti-HIF-1 nanobody, VHH212, was screened via a native ribosome display library with a 26.6 nM of KD value was used as the parent. A mutant with a 17.5-fold enhancement in binding affinity (1.52 nM) was obtained by using the VIMAS strategy. Furthermore, the protein-protein interaction of interface residues, which is important for binding affinity, was analyzed in-depth. Targeting HIF-1 can sensitize PDAC tumors to gemcitabine, which is a potential co-treatment method for pancreatic cancer patients. Under combined treatment, the cytotoxicity of gemcitabine on pancreatic cancer cell lines increased with the enhanced-affinity of an intrabody. Thus, this study provides a platform for universal, efficient and convenient in silico affinity maturation of nanobodies.

biochemistry↗

bioRxiv2020

Rapid and sensitive direct detection and identification of poliovirus from stool and environmental surveillance samples using nanopore sequencing

Global poliovirus surveillance involves virus isolation from stool and environmental samples, intratypic differential (ITD) by PCR and sequencing of the VP1 region to distinguish vaccine (Sabin), vaccine-derived and wild-type polioviruses and ensure an appropriate response. This cell-culture algorithm takes 2-3 weeks on average between sample receipt and sequencing. Direct detection of viral RNA using PCR allows faster detection but has traditionally faced challenges related to poor sensitivity and difficulties in sequencing common samples containing poliovirus and enterovirus mixtures. We present a nested PCR and nanopore sequencing protocol that allows rapid (<3 days) and sensitive direct detection and sequencing of polioviruses in stool and environmental samples. We developed barcoded primers and a real-time analysis platform that generate accurate VP1 consensus sequences from multiplexed samples. The sensitivity and specificity compared with cell-culture were 90.9% (95% Confidence Interval: 75.7-98.1%) and 99.2% (95.5-100.0%) for wild-type 1 poliovirus, 92.5% (79.6-98.4%) and 98.7% (95.4-99.8%) for vaccine and vaccine-derived serotype 2 poliovirus, and 88.3% (81.2-93.5%) and 93.2% (88.6-96.3%) for Sabin 1 and 3 poliovirus alone or in mixtures when tested on 155 stool samples in Pakistan. Variant analysis of sequencing reads also allowed identification of polioviruses and enteroviruses in artificial mixtures and was able to distinguish complex mixtures of polioviruses in environmental samples. The median identity of consensus nanopore sequences with Sanger or Illumina sequences from the same samples was >99.9%. This novel method shows promise as a faster and safer alternative to cell-culture for the detection and real-time sequencing of polioviruses in stool and environmental samples.

microbiology↗

bioRxiv2019

Cardiac nitric oxide synthase 1 worsens heart failure with preserved ejection fraction through S-nitrosylation of histone deacetylase 2

Although the clinical importance of heart failure with preserved ejection fraction (HFpEF), which makes up half of heart failure, has been extensively explored, most therapeutic regimens, including nitric oxide (NO) donors, lack therapeutic benefit1-12. Here we report that neuronal nitric oxide synthase (nNOS, also known as NOS1) induces HFpEF by S-nitrosylation of histone deacetylase 2 (HDAC2). HFpEF animal models--SAUNA (SAlty drinking water/Unilateral Nephrectomy/Aldosterone)13,14 and mild transverse aortic constriction (TAC) mice14,15--showed increased nNOS expression and NO production, which resulted in the S-nitrosylation of HDAC2. HFpEF was alleviated in S-nitrosylation-dead HDAC2 knock-in mice. Pharmacologic intervention by either nNOS inhibition or HDAC2 denitrosylation attenuated HFpEF. Our observations are the first to demonstrate a completely new mechanistic aspect in HFpEF, which may provide a novel therapeutic approach to HFpEF. In addition, our results provide evidence for why conventional NO-enhancement trials have not been effective for improving HFpEF.

molecular biology↗

bioRxiv2018

Heterogeneous susceptibility to rotavirus infection and gastroenteritis in two birth cohort studies: parameter estimation and epidemiological implications

Variation in susceptibility is a known contributor to bias in studies estimating immune protection acquired from vaccination or natural infection. However, difficulty measuring this heterogeneity hinders assessment of its influence on estimates. Cohort studies, randomized trials, and post-licensure studies have reported reduced natural and vaccine-derived protection against rotavirus gastroenteritis in low- and middle-income countries (LMICs). We sought to understand differences in susceptibility among children enrolled in two birth-cohort studies of rotavirus in LMICs, and to explore the implications for estimation of immune protection. We re-analyzed data from studies conducted in Mexico City, Mexico and Vellore, India. Cumulatively, 573 unvaccinated children experienced 1418 rotavirus infections and 371 episodes of rotavirus gastroenteritis (RVGE) over 17,636 child-months. We developed a model characterizing susceptibility to rotavirus infection and RVGE among children, accounting for aspects of the natural history of rotavirus and differences in transmission rates between settings, and tested whether modelgenerated susceptibility measurements were associated with demographic and anthropometric factors. We identified greater variation in susceptibility to rotavirus infection and RVGE in Vellore than in Mexico City. In both cohorts, susceptibility to rotavirus infection and RVGE were associated with male sex, lower birth weight, lower maternal education, and having fewer siblings; within Vellore, susceptibility was also associated with lower socioeconomic status. Children who were more susceptible to rotavirus also experienced higher rates of diarrhea due to other causes. Simulations suggest that discrepant estimates of naturally-acquired immunity against RVGE can be attributed, in part, to between-setting differences in transmission intensity and susceptibility of children. We found that more children in Vellore than in Mexico City belong to a high-risk group for rotavirus infection and RVGE, and demonstrate that bias owing to differences in rotavirus transmission intensity and population susceptibility may hinder comparison of estimated immune protection against RVGE.\n\nAuthor summaryDifferences in susceptibility can help explain why some individuals, and not others, acquire infection and exhibit symptoms when exposed to infectious disease agents. However, it is difficult to distinguish between differences in susceptibility versus exposure in epidemiological studies. We developed a modeling approach to distinguish transmission intensity and susceptibility in data from cohort studies of rotavirus infection among children in Mexico City, Mexico, and Vellore, India, and evaluated how these factors may have contributed to differences in estimates of naturally-acquired immune protection between the studies. We found that more children were at \"high risk\" of acquiring rotavirus infection, and of experiencing gastroenteritis when infected, in Vellore versus Mexico City. The probability of belonging to this high-risk stratum was associated with recognized risk factors such as lower socioeconomic status, lower birth weight, and risk of diarrhea due to other causes. We also found the risk for rotavirus infections to cause symptoms declined with age, and was independent of acquired immunity. Together, these findings can account for estimates of lower protective efficacy of acquired immunity against rotavirus gastroenteritis in high-incidence settings, which mirrors estimates of reduced effectiveness of live oral rotavirus vaccines in low- and middle-income countries.

epidemiology↗

bioRxiv2017

Utility of Shrimp and Der p 10 specific IgE for Shrimp Allergy Diagnosis in Non-House Dust Mite Sensitized Patients

BackgroundThere are no set specific IgE (sIgE) to predict shrimp allergy as cross-reactivity with other arthropods play a role in shrimp sensitization.\n\nObjectiveThis study identifies the allergens associated with shrimp allergy in house dust mite (HDM) and non-HDM sensitized patients.\n\nMethodsPatients with shrimp sensitization (positive skin prick test [SPT] and/or sIgE) with/without history of clinical reaction were recruited. Allergy was confirmed by oral food challenge (OFC) except for patients with history of anaphylaxis. Shrimp allergic (SA) and shrimp tolerant (ST) patients were further classified based on HDM sensitivity. The sIgE to shrimp, shrimp and HDM components were performed. Fishers exact test, Wilcoxon sum rank test and receiver operating characteristics analyses were done.\n\nResultsOf 79 patients recruited, 12 SA (7 positive OFC and 5 with history of anaphylaxis), 18 ST and 10 non-shrimp sensitized controls (NC) were enrolled. In non-HDM sensitized patients, sIgE to shrimp (10.5 kUA/L, p=0.012) and Der p 10 (4.09 kUA/L, p=0.035) were higher in SA patients. Shrimp sIgE [≥]3.55 kUA/L had 100% sensitivity and 85.71% specificity (ROC=0.94[0.81, 1.0]). Der p 10 sIgE [≥]3.98 kUA/L had sensitivity of 80% and specificity of 100% (ROC=0.86[0.57, 1.0]). rPen a 1 [≥]1.1 kUA/L had sensitivity of 80% and specificity of 85.7% (ROC=0.80[0.47,1.0]).\n\nConclusionsIn non-HDM sensitized patients, shrimp sIgE [≥]3.55 kUA/L and Der p 10 sIgE[≥]3.98 kUA/L give 100% sensitivity and specificity, respectively, to diagnose shrimp allergy. HDM sensitivity can influence sIgE levels to shrimp and shrimp/HDM components due to cross-reactivity.

immunology↗