Growth and adaptation to phototrophic conditions of Rhodospirillum rubrum and Rhodopseudomonas sphaeroides at different temperatures

The influence of temperature on yields of cell protein and bacteriochlorophyll as well as on the rates of growth and bacteriochlorophyll synthesis was studied with Rhodospirillum rubrum and Rhodopseudomonas sphaeroides. Under chemotrophic conditions net cell-protein production increased in cultures of both species along with temperature from 14°C up to the optimum at 33°C. Under phototrophic conditions cell-protein yields were largely constant within the range from 21°C to 33°C. At temperatures below 21°C and above 33°C yields decreased. These results are interpreted in terms of coupling between energy yielding or redox equivalent providing metabolisms and cell biosynthesis. Upon adaptation from chemotrophic to phototrophic conditions a direct relationship between temperature increase and bacteriochlorophyll level was observed. Arrhenius plots of both, specific growth rates and rates of bacteriochlorophyll synthesis, revealed discontinuities at about 20°C. Temperature coefficients either above or below those discontinuities were similar in both species. In R. rubrum temperature coefficients of the synthesis of total bacteriochlorophyll were also representative of the synthesis of photochemical reaction center and light harvesting bacteriochlorophylls. But in R. sphaeroides significant differences were observed between temperature coefficients of the syntheses of bacteriochlorophylls of the costantly composed reaction centerlight harvesting complex on one hand and of both, total and the quantitatively variable light harvesting bacteriochlorophylls on the other. The results are interpreted in light of hypotheses on the regulation (a) of cellular bacteriochlorophyll levels as well as (b) of the ratio of functionally different bacteriochlorophylls in the photosynthetic apparatus.Abbreviation Bchl bacteriochlorophyll     

The effect of selected basic dyes on the blood cells,in particular,the basophils,of the Pacific oyster,Crassostrea gigas

It was determined by means of light and electron microscopy that the granular blood cells of Pacific oysters could absorb basic dyes from dye-coated plastic beads injected into the mantles of oysters; in doing so, the granular blood cells became altered morphologically and behaviorally. In addition, it was observed that oysters could absorb the basic dye, toluidine blue O, in low concentration from sea water. It was shown that the absorption of toluidine blue O caused a shift in the blood cell levels of oysters, and it was suggested that this shift was occasioned by the absorption of toluidine blue O by granulocytes.     

Studies on osmotic balance and its control in the freshwater mollusc parreysia corrugata

Percent increase in body weight of 48 hours cerebralactomized mussels in tap water was significantly higher than in control mussels. 48 hours cerebralactomized mussels, injected with cerebral ganglia homogenate, restored their body weight to the normal level in tap water. 48 hours cerebralactomized mussels injected with saline solution did not show any significant increase in weight.The aminoacid levels were studied by introducing the mussels in different salinities. There was an increase in the amino acid content as the percent salinity increased. Thus it may be inferred that osmotic balance in Parreysia corrugata is controlled both by cerebral neurosecretion and by amino acid levels.     

Plasmodium chabaudi: relationship between the occurrence of recrudescent parasitaemias in mice and the effective levels of acquired immunity

In NIH inbred mice infected with the $\text{A}\text{S}$ strain of Plasmodium chabaudi the erythrocytic infection shows an acute primary parasitaemia which becomes subpatent after about 2 weeks. A period (7–10 days) of subpatency follows before a short-lasting patent recrudescence appears. The appearance of the recrudescent parasitaemia was examined in relation to (1) the level of antiplasmodial antibody detected by the indirect fluorescent antibody (IFA) test, (2) the antiparasite activity of the serum measured by the passive protection test, and (3) the ability of the mice to control and eliminate a large intravenous challenge infection. In the period between the primary parasitaemia becoming subpatent and the onset of the recrudescence there was a slight drop in the IFA levels, and a steep decline in passive protective levels and in the ability of the mice to control a large intravenous challenge infection. It is suggested that a decline in the effector arm in the immune response contributes to emergence of the recrudescent parasitaemias.     

Low concentrations of medium-sized HDL particles predict incident CVD in chronic kidney disease patients

Patients with chronic kidney disease (CKD) are at high risk for CVD. However, traditional CVD risk factors cannot completely explain the increased risk. Altered HDL proteome is linked with incident CVD in CKD patients, but it is unclear whether other HDL metrics are associated with incident CVD in this population. In the current study, we analyzed samples from two independent prospective case-control cohorts of CKD patients, the Clinical Phenotyping and Resource Biobank Core (CPROBE) and the Chronic Renal Insufficiency Cohort (CRIC). We measured HDL particle sizes and concentrations (HDL-P) by calibrated ion mobility analysis and HDL cholesterol efflux capacity (CEC) by cAMP-stimulated J774 macrophages in 92 subjects from the CPROBE cohort (46 CVD and 46 controls) and in 91 subjects from the CRIC cohort (34 CVD and 57 controls). We tested associations of HDL metrics with incident CVD using logistic regression analysis. No significant associations were found for HDL-C or HDL-CEC in either cohort. Total HDL-P was only negatively associated with incident CVD in the CRIC cohort in unadjusted analysis. Among the six sized HDL subspecies, only medium-sized HDL-P was significantly and negatively associated with incident CVD in both cohorts after adjusting for clinical confounders and lipid risk factors with odds ratios (per 1-SD) of 0.45 (0.22–0.93, P = 0.032) and 0.42 (0.20–0.87, P = 0.019) for CPROBE and CRIC cohorts, respectively. Our observations indicate that medium-sized HDL-P—but not other-sized HDL-P or total HDL-P, HDL-C, or HDL-CEC—may be a prognostic cardiovascular risk marker in CKD.     

Effect of physiological increments of blood glucose on plasma somatostatin and pancreatic polypeptide levels in dogs

The present study was designed to determine the effects of physiological increments of plasma glucose levels upon basal and stimulated plasma somatostatin and pancreatic polypeptide levels. In seven conscious dogs the elevation of plasma glucose levels by 30-40 mg/dl did not change basal somatostatin and pancreatic polypeptide levels. During stimulation of these two hormones by acetylcholine and the octapeptide of cholecystokinin intravenous infusion of glucose elicited a significant decrease of somatostatin levels by 30 pg/ml and of pancreatic polypeptide levels by 300 pg/ml. The present data demonstrate that a physiological elevation of plasma glucose levels inhibits stimulated but not basal somatostatin and pancreatic polypeptide levels which may be of importance for nutrient entry and metabolism.     

Lifetime changes in the nutritional characteristics of female tsetse Glossina pallidipes caught in odour-baited traps

Female Glossina pallidipes Austen were captured in odour-baited traps at Rekomitjie Research Station, Zambezi Valley, Zimbabwe during February 1994; 2890 were dissected and assigned to their ovarian age category and day of pregnancy using the lengths of the oocytes and uterine content. For 1838 of these flies, the nutritional state of the mother and her uterine content were estimated separately. It was thereby possible to see how, during pregnancy, the females acquired fat and residual dry weight (RDW) and transfered them to the larva. Newly emerged flies contained 1 mg fat and 6 mg RDW, of which 4 mg was in the thorax (TRDW). Fat hardly increased by the first ovulation; RDW increased by 2.5 mg and 1.5 mg of this increase was in TRDW. Mean haematin levels increased from 2 to 8 microg during each pregnancy. Fat increased from 1.2 mg to 4.5-5 mg by day 7 and was then rapidly transferred to the larva. RDW increased by only 1.8 mg by day 7, but larval RDW increased thereafter by > 6 mg. Amino acids from late-pregnancy bloodmeals are incorporated directly, in the uterine gland, into 'milk' that is taken up rapidly by the larva. Capture probability was highest on day 1 of pregnancy, when nutritional levels were lowest, with lesser peaks on days 5 and 8 when the fly was nourishing a rapidly developing larva. On day 1, the peak of the logarithm of the haematin distribution corresponded to flies estimated to have fed approximately 75 h previously; by day 8 it had shifted to approximately 60 h post-feeding. A model in which feeding rates and capture probabilities increased exponentially with time since feeding accounted for 97% of the variance in log haematin frequencies. On 4/9 days of pregnancy there was no significant decline in fat with haematin content during the lipolytic phase. The rate of decline is not a satisfactory estimate of the rate of fat usage. Flies in this study had longer wings and higher TRDW than those from refuges in an earlier study, but had lower levels of fat and haematin.     

Determination of aluminum by neutron activation analysis in human lung tissue and in chemicals for dialysis of uremic patients

Aluminum (Al) determination in human lung tissue, in chemicals for dialysis fluids, and in commercially available dialysis solutions is carried out using both Instrumental and Radiochemical Neutron Activation Analysis (INAA and RNAA). For some matrices, pre-and post-irradiation Al separations are tested. Chelex 100 resin and HDEHP, this latter adsorbed both on teflon and polyurethane foam, are employed for the pre-irradiation Al separations. The postirradiation procedures are performed using roughly the same schemes; the conventional Al precipitation as hydroxide is also carried out. Al values found in lungs of workers exposed to Al containing dust appear to be much higher than those found for unexposed people. Chemicals analyzed seem pure enough to give suitable dialysis solutions; for commercially available dialysis fluids, a 10-fold reduction of Al content should be convenient.     

Contrasting demography of two Patagonian shrubs under different conditions of sheep grazing and resource supply

Summary Two shrub species, dominant in western Patagonia, Argentina, exhibited different demographic behaviors under the effect of sheep grazing and of manipulated resource levels. Senecio filaginoides showed an increase in cover under increasing grazing pressures; the rise was explained by an increasing number of individuals and not by larger plants; this trend was reversed when no grazing took place. Mulinum spinosum showed a slight decrease in cover and density at increasing grazing pressures, and no change in plant size. In a field experiment in which water was added (30 mm in early summer) and the dominant grasses removed, both factors substantially augmented the number of 1-year-old seedlings of Senecio recruited; the only noticeable response of Mulinum was an increase in seedling emergence because of grass removal. Six years after this last treatment, Senecio exhibited a ten fold increase in density, and its population structure showed a peak in younger classes; Mulinum remained unaffected. In seedling surveys conducted within an exclsure and in its surroundings, the emergence of Senecio was similar in these areas in the two years of the study, whereas the emergence of Mulinum was higher inside the exclosure for one of the years. The emergence of Senecio in the wetter year was 3 times larger than in the drier one. Grazing did not affect first-year survival of any species; the major source of seedlign death in this case, as well as in the manipulative experiment, was desiccation during summer drought. We conclude that the contrasting responses of the two species to grazing are mostly due to the greater ability of Senecio to benefit from any increase in resources, including those not used by grazed plants. The difference might also be due to a reduction in the seed availability of Mulinum caused by sheep preference for its fruits. The dissimilar abilities of the two shrubs to employ the resources freed by grazing would derive more from their contrasting demographic potential (i.e. the ability to rapidly increase biomass/m²) than from a difference in their niche overlap with palatable species.