A ternary complex model of Sirtuin4-NAD+-Glutamate dehydrogenase

Sirtuin4 (Sirt4) is one of the mammalian homologues of Silent information regulator 2 (Sir2), which promotes the longevity of yeast, C. elegans, fruit flies and mice. Sirt4 is localized in the mitochondria, where it contributes to preventing the development of cancers and ischemic heart disease through regulating energy metabolism. The ADP-ribosylation of glutamate dehydrogenase (GDH), which is catalyzed by Sirt4, downregulates the TCA cycle. However, this reaction mechanism is obscure, because the structure of Sirt4 is unknown. We here constructed structural models of Sirt4 by homology modeling and threading, and docked nicotinamide adenine dinucleotide+ (NAD+) to Sirt4. In addition, a partial GDH structure was docked to the Sirt4-NAD+ complex model. In the ternary complex model of Sirt4-NAD+-GDH, the acetylated lysine 171 of GDH is located close to NAD+. This suggests a possible mechanism underlying the ADP-ribosylation at cysteine 172, which may occur through a transient intermediate with ADP-ribosylation at the acetylated lysine 171. These results may be useful in designing drugs for the treatment of cancers and ischemic heart disease

ON THE THEORY OF WASHING AND EXTRACTION

When precipitates are washed with a definite quantity of water or some other solvent, it's not recommended to use the washings at the same time. The principle also applies to the extraction between two liquid phases. In almost all analytical textbooks this principle is introduced with the next formula : [numerical formula] In some of them such special numbers, for instance, as n=4 and 5 are put in the formula to show C_5 <C_n

ON THE THEORY OF WASHING AND EXTRACTION

When precipitates are washed with a definite quantity of water or some other solvent, it's not recommended to use the washings at the same time. The principle also applies to the extraction between two liquid phases. In almost all analytical textbooks this principle is introduced with the next formula : [numerical formula] In some of them such special numbers, for instance, as n=4 and 5 are put in the formula to show C_5 <C_n

Expression and subcellular localization of antiporter regulating protein OsARP in rice induced by submergence, salt and drought stresses

We examined the expression and subcellular localization of antiporter regulating protein OsARP in a submergence tolerant rice (Oryza sativa L.) cultivar FR13A. In the public databases, this protein was designated as putative Os02g0465900 protein. The cDNA containing the full-length sequence of OsARP gene was present in Gene Bank Accession no. AK071205 and this encoded 216 amino acids which had molecular mass of 25 kD. The OsARP gene was first expressed into E. coli and antibody was produced by using purified recombinant protein. The expression of OsARP protein was detected under submergence, salt and drought stresses. This protein was widely expressed in roots, shoots and leaves of rice under salt stress. To get an insight into the functional role of OsARP protein, subcellular localization was done using cell fractionation of rice leaves. Immuno-blotting of 3-day submergence rice leaves cell fractions detected the presence of OsARP protein in plasma-membrane fraction only. This indicates that OsARP is a membrane bound protein of rice which is expressed under submergence, salt and drought stresses.Key words: Drought, antiporter regulating protein, immuno-localization, rice, salinity, submergence

Contribuição ao conhecimento da biologia da manjuba, Anchoviella lepidentostole (Fowler, 1911), no estuário de São Vicente, SP (Osteichthyes, Engraulidae)

As many as 3408 specimens from 16 samples were collected in São Vicente Estuary, Sao Paulo, Brazil, from June 1979 to July 1980. The occurrence, growth, length-weight relationship and condition factor of the species are analysed. This estuarine region is one of the areas where the species grows, moving from it when the maturation process begins

The influence of implant–abutment connection on the screw loosening and microleakage

Abstract Background There are some spaces between abutment and implant body which can be a reservoir of toxic substance, and they can penetrate into subgingival space from microgap at the implant–abutment interface. This penetration may cause periimplantitis which is known to be one of the most important factors associated with late failure. In the present study, three kinds of abutment connection system, external parallel connection (EP), internal parallel connection (IP), and internal conical connection (CC), were studied from the viewpoint of microleakage from the gap between the implant and the abutment and in connection with the loosening of abutment screw. Methods We observed dye leakage from abutment screw hole to outside through microgap under the excessive compressive and tensile load and evaluated the anti-leakage characteristics of these connection systems. Results During the experiment, one abutment screw for EP and two screws for IP, out of seven samples in each group, were fractured. After the 2000 cycles of compressive tensile loadings, removal torque value (RTV) of abutment screw represented no statistical differences among three groups. Standard deviation was largest in the RTV of EP and smallest in that of CC. The results of microleakage of toluidine blue from implant–abutment connection indicated that microleakage generally increased as loading procedure progressed. The amount of microleakage was almost plateau at 2000 cycles in CC, but still increasing in other two groups. The value of microleakage greatly scattered in EP, but the deviation of that in CC is significantly smaller. At 500 cycles of loading, there were no significant differences in the amount of microleakage among the groups, but at 1000, 1500, and 2000 cycles of loading, the amount of microleakage in CC was significantly smaller than that in IP. Throughout the experiment, the amount of microleakage in EP was largest, but no statistical difference was indicated due to the high standard deviation. Conclusions Within the limitation of the present study, CC was stable even after the loading in the RTV of abutment screw and it prevented microleakage from the microgap between the implant body and the abutment, among the three tested connections

Contribuição ao conhecimento da biologia da manjuba, Anchoviella lepidentostole (Fowler, 1911), no estuário de São Vicente, SP (Osteichthyes, Engraulidae) Biology of the "manjuba" Anchoviella lepidentostole (Fowler, 1911) from the São Vicente estuary, São Paulo, Brazil (Odeichthyes, Engraulidae)

As many as 3408 specimens from 16 samples were collected in São Vicente Estuary, Sao Paulo, Brazil, from June 1979 to July 1980. The occurrence, growth, length-weight relationship and condition factor of the species are analysed. This estuarine region is one of the areas where the species grows, moving from it when the maturation process begins