COMPARISON OF HEAVY METALS IN AQUATIC PLANTS ON CHARITY ISLAND,SAGINAW BAY,LAKE HURON,U.S.A., WITH PLANTS ALONG THE SHORELINE OF SAGINAW BAY

The concentrations of 15 heavy metals in aquatic plants on Charity Island was compared to those in plants on the shoreline of Saginaw Bay, Lake Huron, U.S.A. Heavy metal concentrations were measured by neutron activation analysis. Charity Island was found to have significantly higher levels of nine of fifteen metals investigated. This indicates that distance from known pollution source was not the only factor affecting the heavy metal accumulation of the aquatic plants.     

Morphometric Differences of Vocal Tract Articulators in Different Loudness Conditions in Singing

IntroductionDynamic MRI analysis of phonation has gathered interest in voice and speech physiology. However, there are limited data addressing the extent to which articulation is dependent on loudness.ResultsThe data show articulatory differences with respect to changes of both pitch and loudness. Here, lip opening and pharynx width were increased. While the vertical larynx position was rising with pitch it was lower for greater loudness. Especially, the lip opening and pharynx width were more strongly correlated with the sound pressure level than with pitch.ConclusionFor the vowel /a/ loudness has an effect on articulation during singing which should be considered when articulatory vocal tract data are interpreted.     

Effect of Short-Term Chilling of Rumen Contents on Viable Bacterial Numbers

Anaerobic storage of whole rumen contents at 0°C for 8 and 24 h resulted in viable colony counts which were 113 and 92%, respectively, of the colony count obtained with an unstored sample. No significant differences in the percentages of the total population capable of utilizing glucose, cellobiose, starch, or xylose occurred with storage. Numerous factors were investigated as possible explanations for the increase in bacterial numbers observed after storage for 8 h in ice. Growth and multiplication of bacteria, subsampling of rumen contents, susceptibility to oxygen, lysis of protozoa with the release of viable bacteria, and rumen sampling time did not appear to be involved. Compilation of the data from all 29 of the above experiments gave a mean value for samples stored for 8 h in ice which was 134.8% of the control (P < 0.005). The effect of storage time at 0°C indicated that a significant increase in colony count occurred after 4 h, and, based on these data, 6 h was subsequently used as the standard cold-storage period. Circumstantial evidence supported the hypothesis that storage of rumen contents for 6 h at 0°C appears to alter or to break down the material responsible for cell-to-cell or cell-to-particulate matter attachment. Addition of a surfactant to the anaerobic dilution solution significantly increased total colony count of rumen contents to an extent similar to chilling in ice for 6 h. However, an additive effect was observed when surfactant-containing anaerobic dilution solution was used with samples stored for 6 h at 0°C.     

Effect of selenium deficiency on tissue taurine concentration and urinary taurine excretion in the rat

The purpose of this study was to determine the effect of selenium deficiency on tissue taurine levels and urinary taurine excretion. Weanling male Sprague-Dawley rats were fed selenium-deficient or selenium-adequate diets for 20 weeks. As selenium deficiency developed, urinary taurine excretion increased in selenium-deficient rats compared to controls. At 12 weeks, the selenium-deficient rats excreted 1.7-fold more taurine than control rats. At the same time plasma glutathione peroxidase was 1.2% of control and plasma glutathione was 226% of control. At 20 weeks, renal taurine was decreased but renal glutathione was increased in selenium-deficient rats compared to controls. Feeding the experimental diet for 6 weeks without methionine supplementation caused a fall in urinary taurine excretion. However, there was no difference between selenium-deficient and control rats. These results indicate that selenium deficiency affects renal handling of taurine in the rat when dietary sulfur amino acids are not restricted.     

RAINFALL PERIODICITY AS A MAJOR FACTOR IN THE FORMATION OF FLOWERING RACES OF CAMPHORWEED (HETEROTHECA SUBAXILLARIS)

Plants of camphorweed (Heterotheca subaxillaris sensu latiore) were raised in a uniform garden at Northampton, Mass., from seed taken from 19 sites in different parts of the range of the species. Flowering races were observed. Flowering time at Northampton correlated with periodicities of rainfall at the seed source in most instances. The earliest-flowering plants were obtained from areas where above-average amounts of rainfall occur in spring, while the later-flowering plants came from sites where above-average rainfall occurs in mid- to late summer. Other workers have observed a correlation between the frost-free season and the formation of flowering races in prairie grasses, Eupatorium rugosum, and other plants. There is little correlation between the frost-free season and the formation of flowering races in Heterotheca and it is postulated that, within the range of camphorweed, periodicity of rainfall is a more critically limiting factor.     

Mechanism of inhibition of junctional communication between animal cells by phorbol ester

Abstract. The tumour promotor 4 β -phorbol 12-myristate 13-acetate (TPA) reduces the rate of junction formation between V79 Chinese hamster lung cells in culture but not between BHK21/13 Syrian hamster fibroblasts. TPA may act on all cells but only affect junction formation in those situations where the rate of junction formation is already low.     

Aging-related occurrence in Ashkenazi Jews of leukocyte heteroplasmic mtDNA mutation adjacent to replication origin frequently remodeled in Italian centenarians

Our previous observation that a mitochondrial DNA (mtDNA) homoplasmic C150T transition adjacent to the heavy strand replication origin at position 151 is greatly increased in frequency in Italian centenarians, as compared to the rest of the population, has prompted us to analyze a genetically distinct population to determine how robust the association of the C150T mutation with longevity is. In particular, we have analyzed leukocyte mtDNA from three groups of an Ashkenazi Jew population, namely, a large number (124) of female centenarians and near-centenarians (95-108 years-old), their mixed gender offspring, and mixed gender control subjects. This analysis revealed a very low incidence of the C150T transition in the probands and the other two groups, and by contrast, the fairly high frequency of a homoplasmic T152C transition and of a homoplasmic T195C transition in all three groups of subjects. Furthermore, most significantly, an aging-related increase in incidence of the heteroplasmic T152C transition, presumably resulting from somatic events, was demonstrated in the Ashkenazi Jews. The T152C transition was not associated with a change in the replication origin at position 151, unlike the C150T transition in the Italian centenarians.