Oxidative stress governs mosquito innate immune signalling to reduce chikungunya virus infection in Aedes-derived cells.

Arboviruses such as chikungunya, dengue and zika viruses cause debilitating diseases in humans. The principal vector species that transmits these viruses is the Aedes mosquito. Lack of substantial knowledge of the vector species hinders the advancement of strategies for controlling the spread of arboviruses. To supplement our information on mosquitoes' responses to virus infection, we utilized Aedes aegypti-derived Aag2 cells to study changes at the transcriptional level during infection with chikungunya virus (CHIKV). We observed that genes belonging to the redox pathway were significantly differentially regulated. Upon quantifying reactive oxygen species (ROS) in the cells during viral infection, we further discovered that ROS levels are considerably higher during the early hours of infection; however, as the infection progresses, an increase in antioxidant gene expression suppresses the oxidative stress in cells. Our study also suggests that ROS is a critical regulator of viral replication in cells and inhibits intracellular and extracellular viral replication by promoting the Rel2-mediated Imd immune signalling pathway. In conclusion, our study provides evidence for a regulatory role of oxidative stress in infected Aedes-derived cells.

Genome-wide identification, characterization and primer designing of simple sequence repeats across Leguminosae family.

Legumes are important clade of commercially important family Leguminosae that mainly include medicinal, flowering and edible plants. Although the genomic sequence of legumes is accessible, only the limited number of effective simple sequence repeat markers has been identified by prior research. Additional polymorphic simple sequence repeats marker discovery will aid in the genetics and breeding of legumes. In this study, 13 complete genome sequences were screened for the identification of chromosome-wise simple sequence repeats (SSRs) and 1,866,861 SSRs were identified. Based on the study, it was observed that the number of SSRs in non-coding region was more as compared to coding region and frequency of mononucleotides was highest followed by di-nucleotides while penta- and hexa-nucleotide repeats were least frequent one. The identified genome-wide SSRs and newly developed SSR markers, primers and their mapping will provide a powerful means for genetic researches across Leguminosae plants, including genetic diversity and evolutionary origin analysis, fingerprinting, QTL mapping and marker-assisted selection for breeding as well as comparative genomic analysis studies.

Aging, oxidative stress and degenerative diseases: mechanisms, complications and emerging therapeutic strategies.

Aging accompanied by several age-related complications, is a multifaceted inevitable biological progression involving various genetic, environmental, and lifestyle factors. The major factor in this process is oxidative stress, caused by an abundance of reactive oxygen species (ROS) generated in the mitochondria and endoplasmic reticulum (ER). ROS and RNS pose a threat by disrupting signaling mechanisms and causing oxidative damage to cellular components. This oxidative stress affects both the ER and mitochondria, causing proteopathies (abnormal protein aggregation), initiation of unfolded protein response, mitochondrial dysfunction, abnormal cellular senescence, ultimately leading to inflammaging (chronic inflammation associated with aging) and, in rare cases, metastasis. RONS during oxidative stress dysregulate multiple metabolic pathways like NF-κB, MAPK, Nrf-2/Keap-1/ARE and PI3K/Akt which may lead to inappropriate cell death through apoptosis and necrosis. Inflammaging contributes to the development of inflammatory and degenerative diseases such as neurodegenerative diseases, diabetes, cardiovascular disease, chronic kidney disease, and retinopathy. The body's antioxidant systems, sirtuins, autophagy, apoptosis, and biogenesis play a role in maintaining homeostasis, but they have limitations and cannot achieve an ideal state of balance. Certain interventions, such as calorie restriction, intermittent fasting, dietary habits, and regular exercise, have shown beneficial effects in counteracting the aging process. In addition, interventions like senotherapy (targeting senescent cells) and sirtuin-activating compounds (STACs) enhance autophagy and apoptosis for efficient removal of damaged oxidative products and organelles. Further, STACs enhance biogenesis for the regeneration of required organelles to maintain homeostasis. This review article explores the various aspects of oxidative damage, the associated complications, and potential strategies to mitigate these effects.

Transcriptome analysis of human macrophages upon chikungunya virus (CHIKV) infection reveals regulation of distinct signaling and metabolic pathways during the early and late stages of infection.

Macrophages are efficient reservoirs for viruses that enable the viruses to survive over a longer period of infection. Alphaviruses such as chikungunya virus (CHIKV) are known to persist in macrophages even after the acute febrile phase. The viral particles replicate in macrophages at a very low level over extended period of time and are localized in tissues that are often less accessible by treatment. Comprehensive experimental studies are thus needed to characterize the CHIKV-induced modulation of host genes in these myeloid lineage cells and in one such pursuit, we obtained global transcriptomes of a human macrophage cell line infected with CHIKV, over its early and late timepoints of infection. We analyzed the pathways, especially immune related, perturbed over these timepoints and observed several host factors to be differentially expressed in infected macrophages in a time-dependent manner. We postulate that these pathways may play crucial roles in the persistence of CHIKV in macrophages.

SARS-CoV-2 variants: Impact on biological and clinical outcome.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that was first identified in December 2019, in Wuhan, China was found to be the etiological agent for a novel respiratory infection that led to a Coronavirus Induced Disease named COVID-19. The disease spread to pandemic magnitudes within a few weeks and since then we have been dealing with several waves across the world, due to the emergence of variants and novel mutations in this RNA virus. A direct outcome of these variants apart from the spike of cases is the diverse disease presentation and difficulty in employing effective diagnostic tools apart from confusing disease outcomes. Transmissibility rates of the variants, host response, and virus evolution are some of the features found to impact COVID-19 disease management. In this review, we will discuss the emerging variants of SARS-CoV-2, notable mutations in the viral genome, the possible impact of these mutations on detection, disease presentation, and management as well as the recent findings in the mechanisms that underlie virus-host interaction. Our aim is to invigorate a scientific debate on how pathogenic potential of the new pandemic viral strains contributes toward development in the field of virology in general and COVID-19 disease in particular.

Impact of CHIKV Replication on the Global Proteome of Aedes albopictus Cells.

Arboviruses are some of the important causative agents of mosquito-mediated viral diseases. These viruses are transmitted between vector and host during the blood meal. Upon viral entry, host replication machinery is hijacked, supporting new virus particle production and thereby allowing viral survival in the host. In this process, host proteins interact with viral proteins to either facilitate viral replication, or they may provide antiviral defense mechanisms. In this study, we analyzed the impact of chikungunya virus (CHIKV) infection on the global proteome of Dicer active Aedes albopictus cells during the early and late time points of infection. We utilized a bottom-up approach of global proteomics analysis, and we used label-free quantitative mass spectrometry to identify the global protein signatures of Ae. albopictus at two different time points upon CHIKV infection. The mass spectrometry data analysis of the early time point revealed that proteins belonging to pathways such as translation, RNA processing, and cellular metabolic processes were less in abundance, whereas those belonging to pathways such as cellular catabolic process and organic substance transport were significantly abundant. At later time points, proteins belonging to pathways such as cellular metabolic processes, primary metabolic process, organonitrogen compound metabolic process, and organic substance metabolic process were found to be decreased in their presence, whereas those belonging to pathways such as RNA processing, gene expression, macromolecule metabolic processing, and nitrogen compound metabolic processing were found to be abundant during CHIKV infection, indicating that modulation in gene expression favoring cell survival occurs at a later time point, suggesting a survival strategy of Aedes cells to counter prolonged CHIKV infection.

Short communication: Virological and B cell profiles of chikungunya and Dengue virus co-infections in Delhi during 2017-2019.

With explosive epidemics of chikungunya in India since 2004, chikungunya virus (CHIKV) now co-circulates in geographical areas where Dengue virus (DENV) is already endemic and thus provides opportunity for the same mosquito to be infected with both viruses. Although there are excellent studies that have addressed the clinical of mono and co-infection, we have little to no knowledge on the current viral sequences that pre-dominate co-infections, and the B cell response elicited. In this study, we analyzed febrile patients that were confirmed to have DENV-CHIKV co-infections and asked the following questions: 1) what is the frequency of co-infections found in a single cycle of transmission; 2) what are the viral sequences associated with them; 3) what does the antibody secreting cell / plasmablast response look like in patients that are co-infected with both viruses. We report those co-infections occur at a frequency of 6.7% in the transmission cycle, and while DENV-3 is now frequently detected, we do not see a serotype bias in the patients that are co-infected with ESCA strain of CHIKV. Moreover, the effector B cell response (plasmablasts) observed are specific to both infecting viruses indicating no overt bias. Further studies to associate whether any of these properties have a bearing on clinical disease manifestation will be both timely and important.

An E3 Ubiquitin Ligase Scaffolding Protein Is Proviral during Chikungunya Virus Infection in Aedes aegypti.

Chikungunya virus (CHIKV) is a reemerging alphavirus causing chikungunya disease (CHIKD) and is transmitted to humans by Aedes mosquitoes. The virus establishes an intricate balance of cellular interactions that ultimately helps in its replication and dodges cellular immune response. In an attempt to identify cellular host factors required during CHIKV replication in Aag2 cells, we performed global transcriptomics of CHIKV-infected Aag2 cells, and further, we compared this library with the Drosophila RNAi Screening Center (DRSC) database and identified transcripts that were regulated in Aedes aegypti during CHIKV infection. These analyses revealed specific pathways, such as ubiquitin-related pathways, proteolysis pathways, protein catabolic processes, protein modification, and cellular protein metabolic processes, involved during replication of the virus. Loss-of-function assays of selected candidates revealed their proviral or antiviral characteristics upon CHIKV infection in A. aegypti-derived Aag2 cells. Further validations identified that the ubiquitin proteasomal pathway is required for CHIKV infection in A. aegypti and that an important member of this family of proteins, namely, AeCullin-3 (Aedes ortholog of human cullin-3), is a proviral host factor of CHIKV replication in Aag2 cells. IMPORTANCE Arboviruses cause several diseases in humans and livestock. Vector control is the main strategy for controlling diseases transmitted by mosquitoes. In this context, it becomes paramount to understand how the viruses replicate in the vector for designing better transmission blocking strategies. We obtained the global transcriptome signature of A. aegypti cells during CHIKV infection, and in order to obtain the maximum information from these data sets, we further utilized the well-characterized Drosophila system and arrived upon a set of transcripts and their pathways that affect A. aegypti cells during CHIKV infection. These analyses and further validations reveal that important pathways related to protein degradation are actively involved during CHIKV infection in A. aegypti and are mainly proviral. Targeting these molecules may provide novel approaches for blocking CHIKV replication in A. aegypti.

Chikungunya virus molecular evolution in India since its re-emergence in 2005.

Chikungunya virus (CHIKV), an alphavirus of the Togaviridae family, is among the most medically significant mosquito-borne viruses, capable of causing major epidemics of febrile disease and severe, chronic arthritis. Identifying viral mutations is crucial for understanding virus evolution and evaluating those genetic determinants that directly impact pathogenesis and transmissibility. The present study was undertaken to expand on past CHIKV evolutionary studies through robust genome-scale phylogenetic analysis to better understand CHIKV genetic diversity and evolutionary dynamics since its reintroduction into India in 2005. We sequenced the complete genomes of fifty clinical isolates collected between 2010 and 2016 from two geographic locations, Delhi and Mumbai. We then analysed them along with 753 genomes available on the Virus Pathogen Database and Analysis Resource sampled over fifteen years (2005-20) from a range of locations across the globe and identified novel genetic variants present in samples from this study. Our analyses show evidence of frequent reintroduction of the virus into India and that the most recent CHIKV outbreak shares a common ancestor as recently as 2006.

Clinical, Serological, Whole Genome Sequence Analyses to Confirm SARS-CoV-2 Reinfection in Patients From Mumbai, India.

Background: SARS-CoV-2 infection may not provide long lasting post-infection immunity. While hundreds of reinfections have reported only a few have been confirmed. Whole genome sequencing (WGS) of the viral isolates from the different episodes is mandatory to establish reinfection. Methods: Nasopharyngeal (NP), oropharyngeal (OP) and whole blood (WB) samples were collected from paired samples of four individuals who were suspected of SARS-CoV-2 reinfection based on distinct clinical episodes and RT-PCR tests. Details from their case record files and investigations were documented. RNA was extracted from the NP and OP samples and subjected to WGS, and the nucleotide and amino acid sequences were subjected to genome and protein-based functional annotation analyses. Serial serology was performed for Anti-N IgG, Anti- S1 RBD IgG, and sVNT (surrogate virus neutralizing test). Findings: Three patients were more symptomatic with lower Ct values and longer duration of illness. Seroconversion was detected soon after the second episode in three patients. WGS generated a genome coverage ranging from 80.07 to 99.7%. Phylogenetic analysis revealed sequences belonged to G, GR and "Other" clades. A total of 42mutations were identified in all the samples, consisting of 22 non-synonymous, 17 synonymous, two in upstream, and one in downstream regions of the SARS-CoV-2 genome. Comparative genomic and protein-based annotation analyses revealed differences in the presence and absence of specific mutations in the virus sequences from the two episodes in all four paired samples. Interpretation: Based on the criteria of genome variations identified by whole genome sequencing and supported by clinical presentation, molecular and serological tests, we were able to confirm reinfections in two patients, provide weak evidence of reinfection in the third patient and unable to rule out a prolonged infection in the fourth. This study emphasizes the importance of detailed analyses of clinical and serological information as well as the virus's genomic variations while assessing cases of SARS-CoV-2 reinfection.

Factors Associated With Elevated Blood Lead Levels in Children.

OBJECTIVE: To determine the prevalence and correlates of elevated blood lead level in children (6-144 months) of Aligarh. METHODS: A hospital-based cross-sectional study was conducted. Venous blood was obtained for lead estimation and a structured questionnaire was filled. RESULTS: A total of 260 children were enrolled. The prevalence of elevated blood lead level was 44.2%, seen mostly in children below 5 years of age. Old and deteriorating wall paints at home was found to be significantly associated with elevated levels. CONCLUSION: Lead-based house paints are potential source of lead exposure. Meticulous renovation and painting of the walls with safe paints is desirable.

PineElm_SSRdb: a microsatellite marker database identified from genomic, chloroplast, mitochondrial and EST sequences of pineapple (Ananas comosus (L.) Merrill).

BACKGROUND: Simple Sequence Repeats or microsatellites are resourceful molecular genetic markers. There are only few reports of SSR identification and development in pineapple. Complete genome sequence of pineapple available in the public domain can be used to develop numerous novel SSRs. Therefore, an attempt was made to identify SSRs from genomic, chloroplast, mitochondrial and EST sequences of pineapple which will help in deciphering genetic makeup of its germplasm resources. RESULTS: A total of 359511 SSRs were identified in pineapple (356385 from genome sequence, 45 from chloroplast sequence, 249 in mitochondrial sequence and 2832 from EST sequences). The list of EST-SSR markers and their details are available in the database. CONCLUSIONS: PineElm_SSRdb is an open source database available for non-commercial academic purpose at http://app.bioelm.com/ with a mapping tool which can develop circular maps of selected marker set. This database will be of immense use to breeders, researchers and graduates working on Ananas spp. and to others working on cross-species transferability of markers, investigating diversity, mapping and DNA fingerprinting.