Insects-plants-pathogens: Toxicity, dependence and defense dynamics.

In a natural ecosystem, the pathogen-plant-insect relationship has diverse implications for each other. The pathogens as well as insect-pests consume plant tissues as their feed that mostly results in damage. In turn, plant species have evolved specialized defense system to not only protect themselves but reduce the damage also. Such tripartite interactions involve toxicity, metabolic modulations, resistance etc. among all participants of interaction. These attributes result in selection pressure among participants. Coevolution of such traits reveals need to focus and unravel multiple hidden aspects of insect-plant-pathogen interactions. The definite modulations during plant responses to biotic stress and the operating defense network against herbivores are vital to research areas. Different types of plant pathogens and herbivores are tackled with various changes in plants, e.g. changes in genes expression, glucosinolate metabolism detoxification, signal transduction, cell wall modifications, Ca2+dependent signaling. It is essential to clarify which chemical in plants can work as a defense signal or weapon in plant-pathogen-herbivore interactions. In spite of increased knowledge regarding signal transduction pathways regulating growth-defense balance, much more is needed to unveil the coordination of growth rate with metabolic modulations in bi-trophic interactions. Here, we addressed plant-pathogen-insect interaction for toxicity as well as dependnce along with plant defense dynamics against pathogens and insects with broad range effects at the physio-biochemical and molecular level. We have reviewed interfaces in plant-pathogen-insect research to show pulsating regulation of plant immunity for attuning survival and ecological equilibrium. An improved understanding of the systematic foundation of growth-defense stability has vital repercussions for enhancing crop yield, including insights into uncoupling of host-parasite tradeoffs for ecological and environmental sustainability.

Contamination of ready-to-eat street food in Pakistan with Salmonella spp.: Implications for consumers and food safety.

OBJECTIVES: Ready-to-eat (RTE) food sold in Quetta, Pakistan was assessed for microbial contamination. METHODS: Equal numbers of samples were collected from four categories of RTE food - burgers, shawarma, pizza and sandwiches - from January 2018 to December 2018. Microbial contamination of individual food samples was assessed by quantifying the total aerobic count obtained from plating samples on bacterial growth medium. Salmonella spp. serovars were identified using polymerase chain reaction. RESULTS: Approximately 38% (121/320) of RTE food samples were not fit for human consumption. The most contaminated type of RTE food was shawarma (49%). Microbial contamination of food samples was higher in summer compared with the other seasons. Approximately 40% (49/121) of food samples that were not fit for human consumption were contamined with Salmonella spp. Salmonella enteritidis (69%) and Salmonella typhimurium (31%) were the only serovars among the samples testing positive for Salmonella spp. Of the 49 samples with high microbial counts, S. enteritidis was present in 34 samples and S. typhimurium was present in 15 samples. The antibiotic sensitivity results demonstrated that both S. enteritidis and S. typhimurium were resistant to amoxicillin. In addition, S. enteritidis was resistant to chloramphenicol and erythromycin, and S. typhimurium presented high resistance to erythromycin. Both S. typhimurium and S. enteritidis were highly sensitive to kanamycin. CONCLUSION: RTE food sold by street vendors in Quetta was found to be contaminated with Salmonella spp. and poses a great health risk to consumers. As such, consumption should be avoided, and the health authorities should take stringent action to ensure the quality of street food in order to reduce the healthcare burden.