Theoretical investigation on ruthenium tetraazaporphyrin as potential nitric oxide carrier in biological systems

Nitric oxide (NO) is an important chemical compound involved in many physiological and pathological processes in living organisms. However, nitric oxide is a very reactive radical that needs to be carried through organisms to reach the desired biological target. With the aim of developing new compounds that can be used as biomedical NO carrier agents we carried out a theoretical investigation at B3LYP/6-31?+?G(d)/LANL2DZ level on the interaction of NO with RuTAP (Ruthenium tetraazaporphyrin) and Ru(L)TAP, where L?=?Clˉ, NH₃, and Pyridine (Py)) and the oxidation state of Ru ranging from +1 to +3. The theoretical calculation results show that the geometric and electronic parameters of the Ru–NO bond are highly dependent on the oxidation state of Ru and of the chemical nature of ligand L at axial position. The results also show clearly that RuTAP and Ru(L)TAP are good potential candidates to be used as NO carriers in living organisms.     

Periodic fasting starves cisplatin‐resistant cancers to death

Treatment of cancers with the cytotoxic agent cisplatin frequently evokes resistance, accompanied by rewiring of metabolic pathways, limiting its clinical use. Recent research by Obrist et al ( 2018 ) shows that cisplatin‐resistant growth of lung adenocarcinoma is particularly vulnerable to periodic fasting cycles and starvation‐induced cell death, due to its dependency on glutamine, required for nucleoside biosynthesis, suggesting an opportunity for nutritional anti‐cancer interventions.     

Human melanoma-associated antigen expression on human neuroblastoma cells: Effects of differentiation inducers

Summary We have described two human melanoma-associated antigens (HMAA), recognized by the murine monoclonal antibodies LS62 and LS109. LS62 recognizes the neuroglandular antigen (NGA), which is overexpressed in neoplastic melanocytes as well as in several tissues of neuroectodermal origin. These antibodies were used to screen six neuroblastoma cell lines and one neuroepithelioma cell line. A melanoma cell line, G361, known to express the two antigens, was used as the positive control. Variable expression of the two antigens was detected in neuroblastoma cells. The surface expression of NGA and of the LS109 antigen was modulated in parallel with the morphological differentiation induced by retinoic acid, 5-bromodeoxyuridine, or cyclic AMP analog/activators. The modulation of the expression of the two HMAA was detected in G361 melanoma cells and in one of the neuroblastoma cell lines, SK-N-SH. These results suggest altered expression of both antigens during melanoma and neuroblastoma cell differentiation in culture.     

Association Between Selenium and Malondialdehyde as an Efficient Biomarker of Oxidative Stress in Infantile Cardiac Surgery

Biological Trace Element Research - The present work describes a method to quantify the level of oxidative stress in infantile cardiac surgery. Fifteen patients, 6 girls and 9 boys, aged between...     

Shell occupation as a limiting factor for Pagurus brevidactylus (Stimpson, 1859) in the Marine State Park of Laje de Santos,Brazil

Hermit crabs are soft-abdomen decapods. They depend upon gastropod shells for protection, with the latter influencing growth rate, mortality and reproduction. The present work aims to provide information about the biology and reproduction of Pagurus brevidactylus in a conservation area in Brazilian southeastern littoral. The material was sampled through active searching by SCUBA diving and refuge traps. We analyzed population structure, fecundity, reproductive output (RO), reproductive periodicity and shell utilization for P. brevidactylus. In total, 54 males, 18 non-ovigerous females, 34 ovigerous females and 10 juveniles were sampled. The females had a fecundity of 69.5 ± 65 eggs, which was lower than that compared to other populations from different localities. The RO ranged from 1.48% to 63.04%, with a mean of 26.75 ± 18.23%. There was a positive relationship between egg number and female size. The animals had continuous reproduction, but they reached smaller maximum sizes when compared with other populations. The shell occupation pattern was also different from other localities, the shells of Phrontis alba being the most occupied; this shell has a smaller size when compared to others that P. brevidactylus occupies in other localities. Therefore, P. alba could have had limited the growth and reproduction of P. brevidactylus.     

Fish gut content from biological collections as a tool for long-term environmental impact studies

Most of the world’s fish fauna is suffering from different types of human impacts and new conservation tools are required. The fish diet analysis is a tool that has been used to evaluate degradation processes of aquatic environments, however, few long-term studies are performed by several reasons (e.g., lack of funding, opportunity). Our aim was to test whether the fish gut content from biological collections can be used for comparisons with current data and, consequently, be used as a tool for long-term environmental impact studies. We compared the gut content of fish preserved for fifteen years in a biological collection with recently sampled fish, considering the factors size of the specimen, preservation time and preservation form. We did not find differences in the gut content percentage of preservation between fish size classes and preservation time. However, we found differences between preservation form, in which the fish fixed in formalin kept the digestive content preserved while the fish preserved directly in alcohol did not. Thus, we encourage the use of fish gut content from biological collections fixed in formalin for long-term ecological studies. Our findings may help elucidate some long-term effects of human impacts on fish fauna.     

Bound detergent molecules in bacterial reaction centers facilitate detection of tetryl explosive

Photosynthesis Research - Bacterial reaction centers (BRC) from Rhodobacter sphaeroides were found to accelerate, about 100-fold, the reaction between tetryl (2,4,6-trinitrophenylmethylnitramine)...