Biology subjects

Raman, T.

Publications and source records attributed to Raman, T..

4 recordsLinked to original sources

bioRxiv2026

Population structure, genetic diversity and global migration of the banana Fusarium wilt pathogen, Fusarium oxysporum f. sp. cubense tropical race 4

O_LIThe current epidemic of banana Fusarium wilt is caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4). Foc TR4 originates in Asia and was first reported in the early 1990s, whereafter it was restricted to five Asian countries and the Northern Territory of Australia for two decades. Since 2013, the fungus was detected in the Middle East, the Indian subcontinent, Africa and Latin America. Its recent spread may be caused by the expansion of Cavendish banana production and the movement of contaminated planting materials. C_LIO_LIWhole genome sequences of 119 Foc TR4 isolates were compared based on single nucleotide polymorphisms (SNPs) to assess the population structure, genetic diversity and relation among isolates from 20 countries to reveal the evolutionary origin and likely migration. C_LIO_LIFoc TR4 is a monophyletic lineage divided into four clusters. Two of the clusters included isolates mostly from eastern Indonesia and seem to be ancestral with many rare alleles and high genetic diversity supporting this region as centre of origin. The remaining clusters were less diverse and associated with pandemic expansion. C_LIO_LIKnowledge on Foc TR4 emergence and dispersal can be used to inform more effective biosecurity and management practice. C_LI

evolutionary biology↗

bioRxiv2024

Partial repair causes permanent defects in papillary structure and function after reversal of urinary obstruction

Urinary obstruction causes injury to the renal papilla and leads to defects in the ability to concentrate urine which predisposes to progressive kidney injury. However, the regenerative capacity of the papilla after reversal of obstruction is poorly understood. To address this, we developed a mouse model of reversible urinary obstruction which is characterized by extensive papillary injury, followed by a robust regeneration response and complete histological recovery over a 3- month period. However, these mice have a pronounced defect in urinary concentrating capacity. We now show that this is due to permanent changes in the composition, organization, and transcriptional signatures of epithelial, endothelial, and interstitial cell lineages in the papilla. There are persistent inflammatory responses that are also seen in patients with renal stone disease but are associated with cell-specific adaptive responses to the increasingly hypoxic environment of the papilla after reversal of obstruction. Taken together, our analysis of a new model of reversible urinary obstruction reveals that partial repair leads to permanent changes in the structure and function of all of the major cellular compartments in the papilla that include both shared and distinct responses to different types of renal papillary injury in humans and mice. SummaryPartial repair after reversal of urinary obstruction leads to permanent changes in structure and function of all major cellular compartments in the renal papilla O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/612436v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@1438af5org.highwire.dtl.DTLVardef@157ff60org.highwire.dtl.DTLVardef@3f09c0org.highwire.dtl.DTLVardef@9950b1_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2021

Comparative proteomic analysis of Fusarium oxysporum f. sp. cubense strains (Foc R1 and Foc TR4) provides better insights into mechanisms of their virulence, habitat adaptation and pathogenesis

Fusarium oxysporum f. sp. cubense (Foc), a devastative soil-borne fungal pathogen causing vascular wilt (i.e. Panama disease) which leads to severe crop losses in most of the banana-growing regions of the world. As there is no single source of effective management practices available so far, understand the pathogenicity of the organism may help in designing effective control measures through molecular approaches. The study aims to compare the proteome of the two pathogenic Foc virulent strains, Race 1 (Foc R1) and tropical race 4 (Foc TR4) that are capable of infecting the Cavendish group of bananas using 2-dimensional (2-D) gel electrophoresis, MALDI-TOF/MS and MS/MS analysis. The results of the study revealed that the proteins, peroxiredoxins, NAD-aldehyde dehydrogenase (NAD-ALDH), MAPK protein, pH-response regulator protein palA/rim-20 and isotrichodermin C15 hydroxylase have shared homology with the fungal proteins, which regulate the osmotic stress response, signal transduction, root colonization and toxin biosynthesis. These are the important functions for the pathogen survival in an unfavourable environment, and successful establishment and infection of the banana host. The present study also identified several putative pathogenicity related proteins in both Foc R1 and Foc TR4. Specifically, certain Foc TR4 specific putative pathogenicity related proteins, phytotoxins biosynthesis gene, fructose 1,6-bisphosphate aldolase class II, Synembryn-like proteins found to contribute strong virulence. Overexpression or knockout of the elective genes could help in devising better control measures for the devastative pathogens in the future. To the best of our knowledge, this is the first report on the proteomics of Foc R1 and Foc TR4 strains of Indian origin that infect Cavendish bananas.

pathology↗

bioRxiv2019

Biofilm of Klebsiella pneumoniae minimize phagocytosis and cytokine expression by macrophage cell line

Infectious bacteria in biofilm mode are involved in many of persistent infections. Owing to its importance in clinical settings many in vitro and in vivo studies have analysed the structural and functional properties of biofilm, its resistance to antibiotic exposure etc. Currently the immune mechanism toward the clearance of biofilm infections is being investigated. K. pneumoniae is one of the major leading causes of biofilm infections on indwelling medical devices. There was no previous literature that demonstrates the interactions of macrophage cells lines and Klebsiella biofilm, as the first report, we investigated the in vitro response of Klebsiella biofilm to phagocytosis and cytokine expression. We developed an in vitro model to study the interactions of Kebsiella biofilm and macrophage. The phagocytosis assay was performed for heat inactivated and live biofilm. A similar phagocytic response against both biofilms were observed when these cells were exposed to RAW 264.7 macrophages. Also, the expressions of TLR2, iNOS, inflammatory cytokines such as IL-{beta}1, IFN-{gamma}, IL-6, IL-12, IL-4, TNF- and anti-inflammatory cytokines, IL-10 during phagocytosis were analysed. These results collectively demonstrated that the rate of phagocytosis was an average of 15% for both biofilms. Also, when activated macrophage was exposed to heat-inactivated or live biofilms, there was a significant increase in proinflammatory cytokine genes together with expected increase in TLR2 and iNOS. Thus, it is clear that macrophage response against biofilm producing K. pneumoniae results in increase in phagocytic rate and a corresponding increase in inflammatory cytokine gene expression which could be important for clearing K. pneumoniae cells.

immunology↗