Cysteine 195 Has a Critical Functional Role in Catalysis by Isocitrate Lyase from Escherichia coli

Cysteine 195 in isocitrate lyase from Escherichia coli has been replaced by directed mutagenesis. Substitution by Ser yields enzyme with a k_cat that is 0.03% that of wild type, and substitution by Ala, Gly, Thr, or Val yields completely inactive enzyme. The present results are consistent with a functional role of Cys 195. Received: 26 March 1997 / Accepted: 29 April 1997     

Schiewerekia podolica Andrz. in Galizien

Ohne Zusammenfassung     

Highly Selective Anti-Cancer Activity of Cholesterol-Interacting Agents Methyl-β-Cyclodextrin and Ostreolysin A/Pleurotolysin B Protein Complex on Urothelial Cancer Cells

Cholesterol content can vary distinctly between normal and cancer cells, with elevated levels in cancer cells. Here, we investigated cholesterol sequestration with methyl-β-cyclodextrin (MCD), and pore-formation with the ostreolysin A/pleurotolysin B (OlyA/PlyB) protein complex that binds to cholesterol/sphingomyelin-rich membrane domains. We evaluated the effects on viability of T24 invasive and RT4 noninvasive human urothelial cancer cells and normal porcine urothelial (NPU) cells. Cholesterol content strongly correlated with cancerous transformation, as highest in the T24 high-grade invasive urothelial cancer cells, and lowest in NPU cells. MCD treatment induced prominent cell death of T24 cells, whereas OlyA/PlyB treatment resulted in greatly decreased viability of the RT4 low-grade noninvasive carcinoma cells. Biochemical and transmission electron microscopy analyses revealed that MCD and OlyA/PlyB induce necrotic cell death in these cancer cells, while viability of NPU cells was not significantly affected by either treatment. We conclude that MCD is more toxic for T24 high-grade invasive urothelial cancer cells, and OlyA/PlyB for RT4 low-grade noninvasive urothelial cancer cells, and neither is toxic for NPU cells. The cholesterol and cholesterol/sphingomyelin-rich membrane domains in urothelial cancer cells thus constitute a selective therapeutic target for elimination of urothelial cancer cells.     

Assessment of biological activities of chitosan Schiff base tagged with medicinal plants

A chitosan Schiff base with an aromatic aldehyde was synthesized and characterized by FTIR and NMR spectroscopies. Furthermore, the degree of substitution was calculated based on the ratios of the area of the proton of the imine (A_imine) and the area of the peak of the proton of the pyranose ring (A_H-2). The antimicrobial activities were determined against bacterial and fungal strains, as well as multiple drug-resistant (MDR) bacteria. The chitosan Schiff base was also tagged with medicinal plants, for example, Curcuma longa, Peganum harmala, Lepidium sativam, and cruciferous vegetables, and the biological activities determined against pathogenic bacterial and fungal strains. The chitosan Schiff base showed maximum zone of inhibition of 22 mm against Staphylococcus aureus with a minimum zone of inhibition of 15 mm against Bacillus cereus. The chitosan Schiff base was fused with C longa, isothiocyanates and a combined mixture of P harmala and L sativam that has shown activities against Escherichia coli with a zone of inhibition of 28, 24, and 30 mm, respectively. The Schiff base of chitosan fused with medicinal plants also showed significant inhibitory activities against MDR bacteria.     

Icariin: a Potential Compound for the Recovery of Tibial Dyschondroplasia Affected Chicken Via Up-Regulating BMP-2 Expression

Background

Tibial dyschondroplasia (TD) is a skeletal disease of fast growing chicken and other avian species. It is characterized by an avascular and non-mineralized growth plate, which leads to a deformed tibial bone and lameness. Unfortunately, this disease is not only responsible for causing huge economic losses but also raises animal welfare concerns. Icariin is a flavonoid, which is isolated from Epimedium pubescens herb, and it has been used to cure different diseases including bone fractures and osteoporosis.

Results

We designed this experiment to use icariin for the treatment of TD affect chickens; for this purpose, a total of 180 chicks were equally divided into three groups: control, TD and icariin. All the three groups were offered ad libitum same normal standard diet with an addition of thiram (50 mg/kg) from 3rd day to 7th day in TD and icariin group in order to induce TD in chickens. After the induction of TD, the chickens in icariin groups were fed standard diet with an addition of icariin at the rate of 10 mg/kg in drinking water to check the therapeutic effect of this flavonoid on TD. Our results showed that the icariin helped in restoring the TD lesion into a normal structure with significantly (P?<?0.05) up-regulating the bone morphogenetic protein-2 (BMP-2) expression in the tibial growth plates (GP).

Conclusions

Icariin increased the vascular area in the growth plate and decreased the average TD score. In conclusion, this study shows that icariin is a potential compound for the recovery of TD affected chickens via up-regulating the BMP-2 expression without posing a threat of ingestion of toxic veterinary drug residues to human beings upon the consumption of treated chickens.

     

Prevalence of exposure of heavy metals and their impact on health consequences

Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal‐induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal‐contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal‐contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed.