Cytosolic glutathione S-transferase in bacteria possesses the biochemical capacity to degrade various classes of organochlorine pollutants in the environment in addition to their primary role of defending the organism from a wide range of endobiotics and xenobiotic substrates. Furthermore, the ability of different classes of cGST to recognize a wide repertoire of substrates due the variability in the substrate binding site of the enzymes makes them well suited for bioremediation purposes. cGSTs act as dehalogenases promoting a rapid degradation of various organochlorine compounds. Dehalogenation served as the primary mechanism for detoxification of various organochlorine compounds, making them vulnerable to attack by other degradative enzymes. However, despite their potential and advantage of wide substrate specificity, cGSTs have not been exploited for bioremediation purposes. In this review, we described the various cGST classes in bacteria and their phylogenetic relationships. Furthermore, the review reiterated that cGSTs in bacteria are involved in dehalogenation reaction, and this property can be harnessed for bioremediation of a diverse class of organochlorine pollutants as they currently represent the largest class of pollutants in the environment.

A glutathione S‐transferase (GST) with a potential dehalogenation function against various organochlorine substrates was identified from a polychlorobiphenyl (PCB)‐degrading organism, Acidovorax sp. KKS102. A homolog of the gene BphK (biphenyl upper pathway K), named BphK‐KKS, was cloned, purified and biochemically characterized. Bioinformatic analysis indicated several conserved amino acids that participated in the catalytic activity of the enzyme, and site‐directed mutagenesis of these conserved amino acids revealed their importance in the enzyme's catalytic activity. The wild‐type and mutant (C10F, K107T and A180P) recombinant proteins displayed wider substrate specificity. The wild‐type recombinant GST reacted towards 1‐chloro‐2,4‐dinitrobenzene (CDNB), ethacrynic acid, hydrogen peroxide and cumene hydroperoxide. The mutated recombinant proteins, however, showed significant variation in specific activities towards the substrates. A combination of a molecular docking study and a chloride ion detection assay showed potential interaction with and a dechlorination function against 2‐, 3‐ and 4‐chlorobenzoates (metabolites generated during PCB biodegradation) in addition to some organochlorine pesticides (dichlorodiphenyltrichloroethane, endosulfan and permethrin). It was demonstrated that the behavior of the dechlorinating activities varied among the wild‐type and mutant recombinant proteins. Kinetic studies (using CDNB and glutathione) showed that the kinetic parameters K_m, V_max, K_cat and K_m/K_cat were all affected by the mutations. While C10F and A180P mutants displayed an increase in GST activity and the dechlorination function of the enzyme, the K107T mutant displayed variable results, suggesting a functional role of Lys107 in determining substrate specificity of the enzyme. These results demonstrated that the enzyme should be valuable in the bioremediation of metabolites generated during PCB biodegradation.

Background: Within a setting without organised breast cancer screening, the characteristics and survival of very early breast cancer were determined. Methods: All 4930 women diagnosed with breast cancer in University Malaya Medical Center, Malaysia from 1993 to 2011 were included. Factors associated with very early presentation (stage I) at diagnosis were identified. Tumour characteristics, management patterns, and survival of very early breast cancer were described, and where appropriate, compared with other settings. Results: Proportion of women presenting with stage I breast cancer significantly increased from 15.2% to 25.2% over two decades. Factors associated with very early presentation were Chinese ethnicity, positive family history of breast cancer, and recent period of diagnosis. Within stage I breast cancers, median tumour size at presentation was 1.5 cm. A majority of stage I breast cancer patients received mastectomy, which was associated with older age, Chinese ethnicity, postmenopausal status, and larger tumours. Chemotherapy was administered in 36% of patients. Five-year age-adjusted relative survival for women with stage I breast cancer was 99.1% (95% CI: 97.6–99.6%). Conclusions: The proportion of women presenting with very early breast cancer in this setting without organised screening is increasing. These women seem to survive just as well as their counterparts from affluent settings.

While diversity studies and screening for enzyme activities are important elements of understanding fungal roles in the soil ecosystem, extracting and purifying the target enzyme from the fungal cellular system is also required to characterize the enzyme. This is, in particular, necessary before developing the enzyme for industrial-scale production. In the present study, partially purified α-amylase was obtained from strains of Pseudogymnoascus sp. obtained from Antarctic and Arctic locations. Partially purified α-amylases from these polar fungi exhibited very similar characteristics, including being active at 15 °C, although having a small difference in optimum pH. Both fungal taxa are good candidates for the potential application of cold-active enzymes in biotechnological industries, and further purification and characterization steps are now required. The α-amylases from polar fungi are attractive in terms of industrial development because they are active at lower temperatures and acidic pH, thus potentially creating energy and cost savings. Furthermore, they prevent the production of maltulose, which is an undesirable by-product often formed under alkaline conditions. Psychrophilic amylases from the polar Pseudogymnoascus sp. investigated in the present study could provide a valuable future contribution to biotechnological applications.