Influence of temperature on the number of Legionella pneumophila in hot water systems

The occurrence of legionella in the hot water systems of two buildings (A and B) was investigated in relation to the water temperature. The peripheral parts of both hot water systems were found to be colonized by these organisms. A temperature of 60C in the hot water mains returning from the building eliminated legionellas from the mains as well as from the peripheral taps and showers. Legionellas could be isolated from taps, showers and the mains when the temperature in the return mains was kept at 54C. The hot water systems could not be completely decontaminated by raising the hot water temperature in the return mains to 70C combined with flushing all the taps and showers. It is suggested that failure to decontaminate the systems is due to dead ends in the pipeline network, which are not reached by the hot water and that these dead ends are the source for recolonization of the systems.     

The structure and evolution of the spider monkey delta-globin gene

We have isolated the delta-globin gene of the New-World spider monkey, Ateles geoffroyi, and compared its nucleotide sequence with those of other primate delta- and beta-globin genes. Among primate delta-globin genes, the rate of nonsynonymous substitutions is much less than the rate of synonymous substitutions. This suggests that primate delta- globin genes may remain under evolutionary conservation, perhaps because hemoglobin A2 has an as yet unknown physiological importance.      

Biochemical pathways in prokaryotes can be traced backward through evolutionary time

For the first time, a credible prokaryotic phylogenetic tree is being assembled by Woese and others using quantitative sequence analysis of oligonucleotides in the highly conservative rRNA. This provides an evolutionary scale against which the evolutionary steps that led to the arrangement and regulation of contemporary biochemical pathways can be measured. This paper presents an emerging evolutionary picture of aromatic amino acid biosynthesis within a large superfamily assemblage of prokaryotes that is sufficiently developed to illustrate a new perspective that will be applicable to many other biochemical pathways.      

Therapy and prevention of gastric ulcer.

After establishing the benign nature of a gastric ulcer, the treatment is primarily medical. This medical therapy is aimed to alleviate symptoms, to heal the ulcer and to prevent relapses. Based on the history of non-steroidal anti-inflammatory drugs (NSAIDs) and the Helicobacter pylori-status, gastric ulcer patients can be divided into four categories (1) H. pylori positive plus NSAID-use, (2) H. pylori positive without NSAID use, (3) NSAID use with negative H. pylori-status, (4) Negative H. pylori-status and no NSAID use. Patients taking NSAIDs should stop this therapy if possible. Patients with gastric H. pylori infection should be treated by a regimen of a proton pump inhibitor with at least two appropriate antibiotics. This treatment will result in early alleviation of symptoms, rapid healing of the ulcer and prophylaxis of ulcer relapse. In patients with gastric ulcer who cannot stop NSAIDs, maintenance therapy with prostaglandins or potent antisecretory drugs should be considered. The few patients with gastric ulcer who do not take NSAIDs and do not have gastric H. pylori infection should be treated by antisecretory drugs, and they should be carefully followed endoscopically to exclude malignant (carcinoma, lymphoma) or non-peptic (Crohn''s disease) disease. All patients with gastric ulcer should be re-endoscoped to verify complete ulcer healing. Surgery may be considered in gastric ulcer patients with complications, in those with severe dysplasia of the gastric mucosa, and in those who are not able or willing to take the medication.     

The evolutionary history of the amylase multigene family in Drosophila pseudoobscura

In Drosophila pseudoobscura, the amylase (Amy) multigene family is contained within a series of inversions, or gene arrangements, on the third chromosome. The Standard (ST), Santa Cruz (SC), and Tree Line (TL) inversions are central to the phylogeny of arrangements, and have clusters of other arrangements derived from them. The gene arrangements belonging to each of these three clusters have a characteristic number of Amy genes, ranging from three in ST to two in SC to one in TL. This distribution pattern can reflect a history of either duplications or deletions, although the data available in the past did not permit a decision between these alternatives. We provide unambiguous evidence that three Amy genes were present before the divergence of the ST, SC, and TL arrangements. Thus, the current status of the Amy multigene family is the result of deletions in the TL and SC arrangements, which created three new pseudogenes: TL Amy2-psi, TL Amy3-psi, and SC Amy3- psi. Analysis of pseudogene sequences revealed that, in the SC and ST arrangements, pseudogene evolution has been retarded, most likely due to the homogenization effect of gene conversion. Finally, by determining the original copy number, we have reconstructed the evolutionary history of the Amy multigene family and linked it with the evolution of the central gene arrangements.      

USE OF SENSORY EVALUATION FOR MEASURING DEODORIZING EFFECTS OF AN AIR CONDITIONER

The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R² values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures.     

Seasonal and long-term soil water regime in West African tropical forest

Abstract. Variation of soil matric potential of a Wet Evergreen and a Moist Semi-deciduous West African forest were compared. The two forest types differed strongly in their soil water regime. Wet Evergreen forest experienced matric potentials below ?100 kPa only occasionally, while in Moist Semi-deciduous forest matric potentials were less than ?2.5 MPa for periods of several weeks or more each season. A water balance equation was used to simulate the soil water regime at both sites and predict severity and length of the dry period. The predictions showed good agreement with the field measurements of soil water potential over a 2-yr period. The methodology was used to estimate the occurrence and severity of droughts over longer periods at the two sites. The balance calculations suggest that droughts occur occasionally in the Wet Evergreen forest under study. The potential impact of droughts on species distribution and vegetation disturbance in tropical forests is discussed.     

Interaction of force transmission and sarcomere assembly at the muscle-tendon junctions of carp (Cyprinus carpio): ultrastructure and distribution of titin (connectin) and α-actinin

At muscle-tendon junctions of red and of white axial muscle fibres of carp, new sarcomeres are found adjacent to existing sarcomeres along the bundles of actin filaments that connect the myofibrils with the junctional sarcolemma. As the filament bundles that transmit force to the junction originate proximal to new sarcomeres, they probably relieve these new sarcomeres from premature loading. In red fibres, these filament bundles are long (up to 20 m) and dense, permitting light-microscopical immunohistochemistry (double reactions: anti-titin or anti--actinin and phalloidin). New sarcomeres have clear I bands; their A band lengths are similar to those of older sarcomeres and the thick filaments lie in register. T tubules are found at the distal side of new sarcomeres but terminal Z lines are absent. The late addition of -actinin suggests that -actinin mainly has a stabilizing role in sarcomere formation. The presence of titin in the terminal fibre protrusions is in agreement with its supposed role in sarcomere formation, viz. the integration of thin and thick filaments. The absence of a terminal Z line from sarcomeres with well-registered A bands suggests that this structure is not essential for the anchorage of connective (titin) filaments.     

The K+/H+ antiporter LeNHX2 increases salt tolerance by improving K+ homeostasis in transgenic tomato

The endosomal LeNHX2 ion transporter exchanges H⁺ with K⁺ and, to lesser extent, Na⁺. Here, we investigated the response to NaCl supply and K⁺ deprivation in transgenic tomato (Solanum lycopersicum L.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K⁺ the opposite was found. Analysis of mineral composition showed a higher K⁺ content in roots, shoots and xylem sap of transgenic plants and no differences in Na⁺ content between transgenic and untransformed plants grown either in the presence or the absence of 120 mm NaCl. Transgenic plants showed higher Na⁺/H⁺ and, above all, K⁺/H⁺ transport activity in root intracellular membrane vesicles. Under K⁺ limiting conditions, transgenic plants enhanced root expression of the high‐affinity K⁺ uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K⁺ depletion rates and half cytosolic K⁺ activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K⁺ and lower cytosolic K⁺ activity than untransformed plants. These results indicate the fundamental role of K⁺ homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.