Measuring ROS and redox markers in plant cells.

Reactive oxygen species (ROS) are produced throughout plant cells as a by-product of electron transfer processes. While highly oxidative and potentially damaging to a range of biomolecules, there exists a suite of ROS-scavenging antioxidant strategies that maintain a redox equilibrium. This balance can be disrupted in the event of cellular stress leading to increased ROS levels, which can act as a useful stress signal but, in excess, can result in cell damage and death.

Promiscuous activity of 3-isopropylmalate dehydrogenase produced at physiological level affords Escherichia coli growth on d-malate.

Promiscuous activities of enzymes may serve as starting points for the evolution of new functions. However, most experimental examples of promiscuity affording an observable phenotype necessitate the artificial overexpression of the target enzyme. Here, we show that 3-isopropylmalate dehydrogenase (IPMDH), an enzyme involved in leucine biosynthesis, has a secondary activity on d-malate, which is sufficient for d-malate assimilation under physiological conditions where the enzyme is upregulated.

Methyl arachidonyl fluorophosphonate inhibits Mycobacterium tuberculosis thioesterase TesA and globally affects vancomycin susceptibility.

Phthiocerol dimycocerosates and phenolic glycolipids (PGL) are considered as major virulence elements of Mycobacterium tuberculosis, in particular because of their involvement in cell wall impermeability and drug resistance. The biosynthesis of these waxy lipids involves multiple enzymes, including thioesterase A (TesA). We observed that purified recombinant M.

Escherichia coli D-malate dehydrogenase, a generalist enzyme active in the leucine biosynthesis pathway.

The enzymes of the β-decarboxylating dehydrogenase superfamily catalyze the oxidative decarboxylation of D-malate-based substrates with various specificities. Here, we show that, in addition to its natural function affording bacterial growth on D-malate as a carbon source, the D-malate dehydrogenase of Escherichia coli (EcDmlA) naturally expressed from its chromosomal gene is capable of complementing leucine auxotrophy in a leuB(-) strain lacking the paralogous isopropylmalate dehydrogenase enzyme. To our knowledge, this is the first example of an enzyme that contributes with a physiologically relevant level of activity to two distinct pathways of the core metabolism while expressed from its chromosomal locus.

Arsenic induced toxicity and histopathological changes in gill and liver tissue of freshwater fish, tilapia (Oreochromis mossambicus).

Acute toxicity of arsenic to tilapia (Oreochromis mossambicus) and its histopathological impacts on gill and liver tissue were evaluated. The median lethal concentration (96 h; LC50) of arsenic (NaAsO₂) was calculated as 28.22 ppm in repeated semi static test method.

Measurements of genotoxic potential of cadmium in different tissues of fresh water climbing perch Anabas testudineus (Bloch), using the comet assay.

The present investigation was undertaken to study the induction of DNA damage by CdCl(2) in freshwater climbing perch Anabas testudineus (Bloch) using alkaline single cell gel electrophoresis (comet assay). The DNA damage was measured in the tissue of gill, kidney and liver as the percentage of DNA in comet tails and comet heads in the tissue of the fish specimens exposed to 0.1, 1.

Assessing the genotoxic potentials of arsenic in tilapia (Oreochromis mossambicus) using alkaline comet assay and micronucleus test.

This experiment was conducted to study the genotoxic potentials of sodium arsenite (NaAsO(2)) in freshwater fish Oreochromis mossambicus by using alkaline comet assay and micronucleus (MN) test. Fish were exposed to three different concentrations (3 ppm, 28 ppm and 56 ppm) of arsenic and gill, liver and blood tissue samples were collected after 48 h, 96 h and 192 h of exposure. Arsenic exposure induced DNA damage in all tissues examined in a concentration dependent manner.

Genetic damage induced by lead chloride in different tissues of fresh water climbing perch Anabas testudineus (Bloch).

The present investigation was undertaken to study the induction of DNA damage by lead chloride (PbCl(2)) in freshwater climbing perch Anabas testudineus using alkaline single cell gel electrophoresis (comet assay). Based on the LC(50) values of lead chloride of A. testudineus three different concentrations viz.