Thermodynamics of equilibria of hemoglobins M Milwaukee-I and Saskatoon and isolated chains of hemoglobin a with carbon monoxide

The thermodynamic parameters of the CO-equilibria of isolated chains of hemoglobin A and of two α-chains in hemoglobins M Milwaukee-I and Saskatoon at 25°, pH 7.0 were determined. The parameters for the binding of the first CO molecule to the hemoglobins M were ΔH′=?17 and ?18 kcal/mole heme and ΔS′=?30 and ?29 e.u. for hemoglobins M Milwaukee-I and Saskatoon, respectively. In contrast to this the characteristics of the second step of the binding were ΔH′=+5.9^· and +4.3 kcal/mole and ΔS′=+51 and +49 e.u. These values for the second step were also significantly different from those of the isolated α-chain (ΔH′=?15 kcal/mole and ΔS′=?11 e.u.).     

Genetic polymorphisms of blood proteins in the troops of Japanese macaques,Macaca fuscata: IV. Erythrocyte esterase polymorphism inMacaca fuscata

Genetic variation at the locus controlling A₁ band of erythrocyte esterase was found in the Japanese macaque,Macaca fuscata. Existence of four alleles,Es-A ₁ ¹ ,Es-A ₁ ² ,Es-A ₁ ³ , andEs-A ₁ ⁴ , controlling the mobility of the band and codominance relation between them were postulated. A majority of the troops examined were monomorphic inEs-A ₁ 1-1 phenotype, and the variant phenotypes were observed to occur only in Yugawara-Ihama, Arashiyama, and Koshima areas.     

Using genetic variation to disentangle the complex relationship between food intake and health outcomes

Diet is considered as one of the most important modifiable factors influencing human health, but efforts to identify foods or dietary patterns associated with health outcomes often suffer from biases, confounding, and reverse causation. Applying Mendelian randomization in this context may provide evidence to strengthen causality in nutrition research. To this end, we first identified 283 genetic markers associated with dietary intake in 445,779 UK Biobank participants. We then converted these associations into direct genetic effects on food exposures by adjusting them for effects mediated via other traits. The SNPs which did not show evidence of mediation were then used for MR, assessing the association between genetically predicted food choices and other risk factors, health outcomes. We show that using all associated SNPs without omitting those which show evidence of mediation, leads to biases in downstream analyses (genetic correlations, causal inference), similar to those present in observational studies. However, MR analyses using SNPs which have only a direct effect on the exposure on food exposures provided unequivocal evidence of causal associations between specific eating patterns and obesity, blood lipid status, and several other risk factors and health outcomes.     

水分胁迫下臭柏（Sabina vulgaris Ant.）光合特性和色素组成的季节变化

在室内砾耕栽培条件下,通过培养液中加入PEG(Polyethylene glycol 分子量为6000)以调节溶液渗透势,设置对照、弱水分胁迫和强水分胁迫3种处理 (培养液渗透势分别为0.02,-0.1,-0.34 MPa), 从1997年开始对臭柏进行长期干旱胁迫模拟实验.2003年测定了臭柏叶片光合色素和光合特性的季节变化.结果表明:对照区气孔导度季节变化在5月和9月份形成了典型的双峰曲线.尽管对照区的气孔导度明显高于其他两个处理,但日光合量却低于弱水分胁迫区.3个处理Chl a/b的比值在11月至翌年3月的低温期内均升高,以强水分胁迫区的增幅最大,其它月份该比值在3个处理之间没有显著的差异.3个处理的叶绿素总量(Chl a+b)在生长季的5～9月份均有不同程度的上升,但其中以强水分胁迫区增幅最小.在11月至翌年3月的低温期,各处理均大幅提高叶黄素总量(V+A+Z)和热耗散色素比例(A+Z)/(V+A+Z) (V:紫黄质、A:单环氧玉米黄质、Z:玉米黄质);在5～7月份的生长高峰期,各处理则明显降低了叶黄素总量和热耗散色素比例.这种趋势在强水分胁迫区表现的更为显著.     

Acquired Thermotolerance and Temperature-Induced Protein Accumulation in the Extremely Thermophilic Bacterium Rhodothermus obamensis

Temperature-induced changes in thermotolerance and protein composition were examined in heat-shocked cells and high-temperature-grown cells of the extremely thermophilic bacterium Rhodothermus obamensis. The survival at temperatures superoptimal for growth (90 and 95°C) was enhanced in both heat-shocked cells and high-temperature-grown cells relative to that of cells grown at optimal temperatures. In a comparison of protein composition using two-dimensional gel electrophoresis, putative heat shock proteins (HSPs) and high-temperature growth-specific proteins (HGPs) were detected. N-terminal amino acid sequence analysis revealed that the putative HSPs were quite similar to the ATP-binding subunits of ABC transporters and the HGPs were proteins corresponding to domains II and III of elongation factor Tu. These results suggested that this extreme thermophile has developed temperature-induced responses that include increased survival under hyperthermal conditions, changes in protein composition, and also the production of novel HSPs.     

Characterization of humoral responses in mice immunized with plasmid DNAs encoding SARS-CoV spike gene fragments

The immunological characteristics of SARS-CoV spike protein were investigated by administering mice with plasmids encoding various S gene fragments. We showed that the secreting forms of S1, S2 subunits and the N-terminus of S1 subunit (residues 18-495) were capable of eliciting SARS-CoV specific antibodies and the region immediate to N-terminus of matured S1 protein contained an important immunogenic determinant for elicitation of SARS-CoV specific antibodies. In addition, mice immunized with plasmids encoding S1 fragment developed a Th1-mediated antibody isotype switching. Another interesting finding was that mouse antibodies elicited separately by plasmids encoding S1 and S2 subunits cooperatively neutralized SARS-CoV but neither the S1 nor S2 specific antibodies did, suggesting the possible role of both S1 and S2 subunits in host cell docking and entry. These results provide insights into understanding the immunological characteristics of spike protein and the development of subunit vaccines against SARS-CoV.     

Prolamellar bodies formed by cyanobacterial protochlorophyllide oxidoreductase in Arabidopsis

In angiosperms, chlorophyll biosynthesis is light dependent. A key factor in this process is protochlorophyllide oxidoreductase (POR), which requires light to catalyze the reduction of protochlorophyllide to chlorophyllide. It is believed that this protein originated from an ancient cyanobacterial enzyme that was introduced into proto‐plant cells during the primary symbiosis. Here we report that PORs from the cyanobacteria Gloeobacter violaceus PCC7421 and Synechocystis sp. PCC6803 function in plastids. First, we found that the G. violaceus POR shows a higher affinity to its substrate protochlorophyllide than the Synechocystis POR but a similar affinity to plant PORs. Secondly, the reduced size of prolamellar bodies caused by a knockdown mutation of one of the POR genes, PORA, in Arabidopsis could be complemented by heterologous expression of the cyanobacterial PORs. Photoactive protochlorophyllide in the etioplasts of the complementing lines, however, was retained at a low level as in the parent PORA knockdown mutant, indicating that the observed formation of prolamellar bodies was irrelevant to the assembly of photoactive protochlorophyllide. This work reveals a new view on the formation of prolamellar bodies and provides new clues about the function of POR in the etioplast–chloroplast transition.