Polyhydroxyalkanoate (PHA) is a promising candidate for use as an alternative bioplastic to replace petroleum-based plastics. Our understanding of PHA synthase PhaC is poor due to the paucity of available three-dimensional structural information. Here we present a high-resolution crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, PhaCCs-CAT. The structure shows that PhaCCs-CAT forms an α/β hydrolase fold comprising α/β core and CAP subdomains. The active site containing Cys291, Asp447 and His477 is located at the bottom of the cavity, which is filled with water molecules and is covered by the partly disordered CAP subdomain. We designated our structure as the closed form, which is distinct from the recently reported catalytic domain from Cupriavidus necator (PhaCCn-CAT). Structural comparison showed PhaCCn-CAT adopting a partially open form maintaining a narrow substrate access channel to the active site, but no product egress. PhaCCs-CAT forms a face-to-face dimer mediated by the CAP subdomains. This arrangement of the dimer is also distinct from that of the PhaCCn-CAT dimer. These findings suggest that the CAP subdomain should undergo a conformational change during catalytic activity that involves rearrangement of the dimer to facilitate substrate entry and product formation and egress from the active site.

Background: Moringa oleifera belongs to plant family, Moringaceae and popularly called -wonderful tree‖, for it is used traditionally to cure many diseases including cancer in Africa and Asia, however, there is limited knowledge on cytotoxic activity of Moringa oleifera seeds on MCF7 breast cancer cell. The present study evaluated antiproliferative effect on MCF7 of the seed. Materials and Methods: Seeds of Moringa oleifera were grinded to powder and its phytochemicals were extracted using water and 80% ethanol solvents, part of the ethanolic extract were sequentially partitioned to fractions with four solvents (hexane, dichloromethane, chloroform, and n-butanol). Antiproliferative effects on MCF7 of the samples were determined. Finally, potent samples that significantly inhibited MCF7 growth were tested on MCF 10A. Results: Crude water extract, hexane and dichloromethane fractions of the seeds inhibited the proliferation of MCF7 with the following IC 50 values 280 µg/ml, 130 µg/ml and 26 µg/ml respectively, however, of the 3 samples, only hexane fraction had minimal cytotoxic effect on MCF 10A (IC 50 > 400µg/ml). Conclusion: Moringa oleifera seed has antiproliferative effect on MCF7.

The zebrafish (Danio rerio) is used as an embryonic and larval model to perform in vitro experiments and developmental toxicity studies. Zebrafish may be used to determine the toxicity of samples in early screening assays, often in a high-throughput manner. The zebrafish embryotoxicity model is at the leading edge of toxicology research due to the short time required for analyses, transparency of embryos, short life cycle, high fertility, and genetic data similarity. Zebrafish toxicity studies range from assessing the toxicity of bioactive compounds or crude extracts from plants to determining the optimal process. Most of the studied extracts were polar, such as ethanol, methanol, and aqueous solutions, which were used to detect the toxicity and bioactivity. This review examines the latest research using zebrafish as a study model and highlights its power as a tool for detecting toxicity of medicinal plants and its effectiveness at enhancing the understanding of new drug generation. The goal of this review was to develop a link to ethnopharmacological zebrafish studies that can be used by other researchers to conduct future research.

Clinacanthus nutans is an essential medicinal plant that had been used in various local remedies to treat many illnesses. A study had been conducted to determine the phenolic, flavonoid, antioxidant activities and phytochemical compounds of C. nutans in different locations. C. nutans were harvested from eight locations and the leaves were extracted with 80 % methanol by maceration process. Then, the phytochemical screening using Gas Chromatography-Mass Spectrometry (GC-MS), 2,2 diphenyl-2-picrylhydrazyl hydrate (DPPH) assay method, total phenolic content by Folin-Ciocalteu's assay method and total flavonoid content by aluminium chloride (AlCl 3 ) were carried out. The C. nutans extracts showed higher antioxidant activities than phenolic and flavonoid content. The neutral pH sandy clay soil from location KKK (Kuala Ketil, Kedah, Malaysia) had higher antioxidant activities (58.0 %), phenolic (44.1 mg GA.100 g -1 ) and flavonoid content (30.8 mg QE.100 g -1 ) compared to other locations. The GC-MS analysis showed the presence of phytochemicals constituents of 20 compounds. The results revealed that environmental factors (light intensity, temperature and soil characteristics) of eight locations were responsible for variations of phenolic, flavonoids, antioxidants and GC-MS analysis in C. nutans. The findings of this study will provide baseline data for future breeding programs for commercial cultivation.

vascular disease) affecting therapyial preliminary considerations of dental implant treatment. However, in case of HIV-positive patients, the dental implant failure rate would not increase due to affective factors (e.g., prophylactic antibiotic treatment, the administration of active antiretroviral therapy, and control of the CD 4+ T lymphocyte counts). Therefore, these patients have no clinical signs of mobility or infection in this treatment and much more attention should be paid to these patients and they should be treated with controlled oral surgical procedures.