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The methanol extract of Camellia sinensis (MES) and acetone extract of Camellia assamica (AEA) were subjected to the thin layer chromatography to separate the bioactive compounds. The antimicrobial activity of all the fractions was carried out against pathogenic microorganisms by the agar-well diffusion method. The most effective bioactive fraction of each plant species was analysed by GC–MS. Fraction L of methanol extract of C. sinensis (MES) and fraction 5 of acetone extract of C. assamica (AEA) were found very effective against selected pathogenic strains. GC–MS analysis of this fraction showed the presence of n-heptadecanol-1 (68.63%) in MES and 2′,6′dihydroxyacetophenone, bis(trimethylsilyl) (17.58%) in AEA with the highest area. The compounds n-heptadecanol-1 and 2′,6′dihydroxyacetophenone, bis(trimethylsilyl) ether were used for docking to analyse its therapeutic potential. The ligand compound n-heptadecanol-1 (HEP) from MES of C. sinensis and 2′,6′dihydroxyacetophenone, bis(trimethylsilyl) ether from AEA of C. assamica were docked with the target protein dihydropteoate synthase (DHPS) active sites of Escherichia coli and Staphylococcus aureus active sites via Auto Dock Vina, thereby forecasting the finest binding position of ligands. AutoDock Vina docked results revealed the involvement of binding energy for the establishment of the protein–ligand structure complex, besides generating an interpretation of all apparent molecular interactions accountable for its activity. Further, the protein–ligand complex of MES, EcDHPS + HEP and SaDHPS + HEP exhibiting the best binding affinity were − 4.8 kcal/mol and − 3.6 kcal/mol. The protein–ligand complex of AEA, i.e., EcDHPS + DHA and SaDHPS + DHA exhibited the best binding affinity of − 4.8 kcal/mol and − 4.8 kcal/mol. [ABSTRACT FROM AUTHOR]

The genus Colletotrichum comprises a large number of filamentous fungi responsible for anthracnose diseases in many tropical and subtropical fruits and vegetables. In particular, Colletotrichum higginsianum infects Brassicaceae species, including Arabidopsis. The C. higginsianum strain IMI349063A is naturally infected with a dsRNA virus, named Colletorichum higginsianum non-segmented virus (ChNRV1). Here, we investigated the biological effect of ChNRV1 in C. higginsianum by comparing strains with and without the virus. ChNRV1 does not have an effect on C. higginsianum growth under salt and cell-wall stress conditions. However, thermal stress reduced C. higginsianum growth rate, this effect being more evident in the wild-type C. higginsianum strain containing the virus. Although ChNRV1 had no effect in conidiation, conidia were narrower when the virus is present. More importantly, ChNRV1 causes a mild increase in C. higginsianum virulence (hypervirulence) when infecting Arabidopsis plants. These findings indicated that, whereas the ChNRV1 mycovirus does not impair growth and conidiation of C. higginsianum, it confers hypervirulence to the fungal host. These findings will help in future research on the effect of mycoviral infection on pathogenic fungi in plant species of agronomical relevance. [ABSTRACT FROM AUTHOR]

Genomic instability resulting from oxidative stress responses may be traced to chromosomal aberration. Oxidative stress suggests an imbalance between the systemic manifestation of reactive free radicals and biological system's ability to repair resulting DNA damage and chromosomal aberration. Bacterial infection associated insult is considered as one of the major factors leading to such stress conditions. To study free radical responses by host cells, RAW 264.7 macrophages were infected with non-pathogenic M. smegmatis mc2155 at different time points. The infection process was followed up with an assessment of free radical stress, cytokine, toll-like receptors (TLRs) and the resulting DNA damage profiles. Results of CFU count showed that maximum infection in macrophages was achieved after 9 h of infection. Host responses to the infection across different time periods were validated from nitric oxide quantification and expression of iNOS and were plotted at regular intervals. IL-10 and TNF-α expression profile at protein and mRNA level showed a heightened pro-inflammatory response by host macrophages to combat M. smegmatis infection. The expression of TLR4, a receptor for recognition of mycobacteria, in infected macrophages reached the highest level at 9 h of infection. Furthermore, comet tail length, micronuclei and γ-H2AX foci recorded the highest level at 9 h of infection, pointing to the fact that breakage in DNA double strands in macrophage reaches its peak at 9 h of infection. In contrast, treatment with ROS inhibitor N-acetyl-l-cysteine (NAC) prevented host cell death through reduction in oxidative stress and DNA damage response during M. smegmatis infection. Therefore, it can be concluded that enhanced oxidative stress response in M. smegmatis infected macrophages might be correlated with DNA damage response. [ABSTRACT FROM AUTHOR]