Surface water quality and information about the environment surrounding Inle Lake in Myanmar

Inle Lake is the second largest lake in Myanmar and one of the nine key sites for sightseeing there. An analysis of its water quality has not been published before. The objective of this study is to reveal the current situation and find any major problems with the lake. For this purpose, the natural and cultural environments were examined. Some physical and chemical aspects of the surface water were assayed in situ for 2 days in November 2004. The principal ions were analyzed in our laboratory. The main cation and anion species in the lake surface water are Ca²⁺ and HCO₃ ⁻. Its high calcium content can be attributed to the limestone of Shan Plateau around the lake. The alkalinity of the lake water was 3829–4114 acid-neutralizing capacity (ANC) (pH 7.8–8.0); it can be attenuated by Ca²⁺. The concentrations of PO₄-P, NO₂-N, and NO₃-N were relatively high; these could originate from domestic and agriculture uses. The trophic state is eutropic. The concentrations of coliform bacteria indicated that the lake water was unfit to drink, but some people use it for drinking anyway. The bacteria could enter the lake through the direct latrine system used there. The thermal type of the lake is presumed to be warm polymictic. More extensive studies are needed because the lake is thought to be the most changing site in Myanmar as a result of both the tourism boom and increasing agricultural activity.     

Co-overproducing Rubisco and Rubisco activase enhances photosynthesis in the optimal temperature range in rice

Rubisco limits C₃ photosynthesis under some conditions and is therefore a potential target for improving photosynthetic efficiency. The overproduction of Rubisco is often accompanied by a decline in Rubisco activation, and the protein ratio of Rubisco activase (RCA) to Rubisco (RCA/Rubisco) greatly decreases in Rubisco-overproducing plants (RBCS-ox). Here, we produced transgenic rice (Oryza sativa) plants co-overproducing both Rubisco and RCA (RBCS-RCA-ox). Rubisco content in RBCS-RCA-ox plants increased by 23%–44%, and RCA/Rubisco levels were similar or higher than those of wild-type plants. However, although the activation state of Rubisco in RBCS-RCA-ox plants was enhanced, the rates of CO₂ assimilation at 25°C in RBCS-RCA-ox plants did not differ from that of wild-type plants. Alternatively, at a moderately high temperature (optimal range of 32°C–36°C), the rates of CO₂ assimilation in RBCS-ox and RBCS-RCA-ox plants were higher than in wild-type plants under conditions equal to or lower than current atmospheric CO₂ levels. The activation state of Rubisco in RBCS-RCA-ox remained higher than that of RBCS-ox plants, and activated Rubisco content in RCA overproducing, RBCS-ox, RBCS-RCA-ox, and wild-type plants was highly correlated with the initial slope of CO₂ assimilation against intercellular CO₂ pressures (A:Ci) at 36°C. Thus, a simultaneous increase in Rubisco and RCA contents leads to enhanced photosynthesis within the optimal temperature range.

A simultaneous increase in Rubisco and RCA contents in transgenic rice leads to an enhancement of photosynthesis at moderately high temperatures within the optimal temperature range.     

Low Cadmium Levels in Urine of Residents in two Prefectures where Cadmium Levels in Locally Harvested Brown Rice are Higher than in other Prefectures in Japan

Recent publications in Japan suggest that Cd in river beds and locally harvested rice tend to be higher in seven prefectures in the north-eastern part on the coast of the Sea of Japan (the high-Cd zone). The present study was initiated to investigate the current level of exposure to Cd and possible health effects among local populations in the zone. Thus, levels of Cd and three tubular dysfunction markers [i.e., α ₁-MG, β ₂-MG, and N-acetyl-β-d-glucosaminidase (NAG)] were examined in urine of local residents (700 and 704 adult women, respectively) in two prefectures (prefecture 1 and prefecture 7), which were located in the north-east (prefecture 1) and south-west ends (prefecture 7) of the high-Cd zone. Urinary Cd levels [e.g., 0.99 and 0.78 μg/l as geometric mean (GM) for observed (non-corrected) values, respectively] in prefecture 1 and prefecture 7 were comparable to the levels in other parts of Japan (All Japan-A; 0.99 μg/l). Correspondingly, GM values for α ₁-MG (2.29 and 1.99 mg/l vs. 2.17 mg/l for All Japan-A) and for β ₂-MG (87 and 80 μg/l vs. 99 μg/l for All Japan-A) were not elevated, and NAG also stayed unchanged (2.89 and 2.87 units/l for prefecture 1 and prefecture 7, respectively). Evaluation in combination with the findings in other five prefectures in the zone suggests that Cd exposure is equal to the national average both in prefecture 1 and in prefecture 7, whereas Cd exposure appeared to be elevated in the central part of the zone. The observation appears to be on line with geographical location of the two prefectures that they are on the two ends of the zone of high natural Cd background.     

Optimal conditions for blastogenic response of peripheral blood lymphocytes to T and B cell mitogens in cynomolgus monkeys

Optimal conditions for the mitogen-induced proliferation of T and B lymphocytes of cynomolgus monkeys were determined. The T cell mitogens concanavalin A and phytohemagglutinin, at concentrations of 1.25–10 μg/ml and 1.25–10 μg/ml, respectively, and the T and B cell mitogen pokeweed mitogen, at concentrations of 0.2–10 μg/ml, induced high lymphoproliferative responses, the average stimulation index (SI) being 34–93. Since suitable mitogens have not been reported for monkey B cells, we tested three types of lipopolysaccharide (LPS): two derived from Escherichia coli—one extracted with phenol and one extracted with trichloroacetic acid (TCA); and one derived from Salmonella typhimurium, extracted with phenol. All three LPS had a high mitogenic effect for monkey lymphocytes, with SI of 2.3–6.4. The highest response was observed for 25 μg/ml of Salmonella LPS, and the addition of trypsin to the culture augmented the proliferative response of low or non-responder lymphocytes. © 1994 Wiley-Liss, Inc.     

Cell surface changes accompanying aging in human diploid fibroblasts : II. Two types of age-related changes revealed by concanavalin A-mediated red blood cell adsorption

Age-related changes in cell surfaces of human diploid fibroblasts (TIG-1) were investigated using the concanavalin A (ConA)-mediated red blood cell (RBC) adsorption assay. When ConA-coated RBCs were adsorbed to fibroblasts (RBC coating method), the amount of RBCs adsorbed per mg of fibroblast protein increased continuously from the early phases of cell passage up through cell senescence. On the other hand, when RBCs were adsorbed to ConA-coated fibroblasts (fibroblast coating method), RBC adsorption did not occur throughout phase II and increased with the advance of phase III. [³H]ConA binding to fibroblasts, however, did not change with aging to the extent that could explain the observed changes in RBC adsorption. These age-related characteristics in RBC adsorption and [³H]ConA binding were also observed for WI38 and IMR-90 cells. In addition, SV40- and ⁶⁰Co-transformed WI38 cells showed a close resemblance in their RBC adsorption capacity to early phase III cells.RBC adsorption with both the RBC and fibroblast coating methods was not a function of cell cycle phase and time spent in culture (metabolic time). Co-culturing of young cells with old or transformed cells did not affect the RBC adsorption capacity of respective cells. These results suggest that RBC adsorption with the RBC and fibroblast coating methods may represent cell surface markers for division age and senescence of aging human diploid cells.     

Analysis of Odor Discrimination by Multidimensional Scaling at Different Temperatures

Discrimination of odorants by the turtle olfactory bulb at 25°and 37°C was examined by the cross-adaptation techniqueand analysed by multidimensional scaling. Analysis by multidimensionalscaling suggests that at 25°C odorants are grouped accordingto their odor qualities in the turtle olfactory system. At 37°C,the cluster formation of odorants, which have a similar odorquality, such as minty and floral alcohol odorants and molecularstructure, in the plot of multidimensional scaling was poor,indicating that the ability of odor grouping according to theirodor qualities was low at 37°C. Chem. Senses 20: 565–571,1995.