Chronic Administration of Lithium Chloride Increases Immunodetectable Glial Fibrillary Acidic Protein in the Rat Hippocampus

Abstract: We studied the effect of treating rats with lithium salts on the content and in vitro phosphorylation rate of the astrocyte cell marker, glial fibrillary acidic protein (GFAP), in brain slices. Rats were fed a diet incorporating lithium chloride until the concentration of Li⁺ in serum reached 0.6–1.2 m M , a range similar to that achieved in clinical practice. Hippocampal tissue was analyzed for immunoreactive GFAP by a dot assay, and slices of hippocampus and caudate nucleus were labeled with [³²P]-phosphate to determine the in vitro rate of phosphorylation of GFAP. Compared with controls, the level of immunoreactive GFAP in the hippocampus from lithium-treated rats was increased 34%, and GFAP in hippocampal slices incorporated 39% more ³²P. This effect of lithium was apparently not confined to the hippocampus because the in vitro rate of phosphorylation of GFAP in caudate slices was also increased in the treated rats.     

Changes in drinking water selenium and mortality for coronary disease in a residential cohort

In a part of the municipal territory of Reggio Emilia, northern Italy, selenium in drinking water decreased from 7 μg/L to less than 1 μg/L. In a cohort of 4419 individuals, previously exposed for at least 5 yr to the drinking water with higher selenium content, the 7-yr temporal distribution of deaths for coronary disease and for stroke was analyzed to examine a possible relationship with changes in drinking water selenium. From January 1986 until August 1988, when tap water selenium was 7 μg/L, deaths for coronary disease were one in males and two in females. After the decrease in drinking water selenium, 21 and 10 coronary deaths were observed, respectively, in males and in females from September 1988 to December 1992. No significant difference in the temporal distribution of stroke deaths was observed both in males and in females. Even if an effect of chance and aging in the temporal distribution of coronary deaths may not be excluded, findings of the study seem to be consistent with the hypothesis of a beneficial effect of selenium on coronary disease mortality.     

Human T Cell Leukemia Virus Type 1 (HTLV-1) Antibodies in Healthy Populations and Renal Transplanted Patients in the North-East of Brazil

The seroprevalence of human T cell leukemia virus type 1 (HTLV-1) infection was investigated in Brazilians (570): native inhabitants (298) and descendants from Japanese (272) living in Recife and its neighborhoods—North-east of Brazil. Furthermore, polytransfused renal transplanted patients (54) were also examined for the serological status to this virus. The seropositivity to HTLV-1, screened by enzyme-linked immunosorbent assay (ELISA), was low: 1.34% for the local population and 0.73% for the descendants from Japanese. However, the seropositivity for the renal transplanted patients was found to be 11.1%. This higher value suggests that this retrovirus infection seems to be of importance in this clinical condition.     

Repeated-batch cultures of Baby Hamster Kidney cell aggregates in stirred vessels

Natural aggregates of Baby Hamster Kidney cells were grown in stirred vessels operated as repeated-batch cultures during more than 600 hours. Different protocols were applied to passaging different fractions of the initial culture: single cells, large size distributed aggregates and large aggregates. When single cells or aggregates with the same size distribution found in culture are used as inoculum, it is possible to maintain semi-continuous cultures during more than 600 hours while keeping cell growth and viability. These results suggest that aggregate culture in large scale might be feasible, since a small scale culture can easily be used as inoculum for larger vessels without noticeable modification of the aggregate chacteristics. However, when only the large aggregates are used as inoculum, it was shown that much lower cell concentrations are obtained, cell viability in aggregates dropping to less than 60%. Under this selection procedure, aggregates maintain a constant size, larger than under batch experiments, up to approximately 400 hours; after this time, aggregate size increases to almost twice the size expected from batch cultures.     

Round-cell mutants of Salmonella typhimurium produced by transposition mutagenesis: Lethality of rodA and mre mutations

Summary Thirty-three insertions of transposon Tn10l6l7 into genes involved in the control of rod cell shape were isolated in Salmonella typhimurium by the characteristic glossy appearance of colonies composed of spherical cells. Genetic tests demonstrated that 25 (76%) were insertions in the rodA gene, 7 (21 %) were mre mutants, and 1 (3%) was a divD mutant. No insertion in the pbpA gene were found. Insertions in cell shape genes only appeared when strains displaying resistance to mecillinam (not caused by -lactamase production) were employed. Neither rodA nor mre insertions could be transduced to wild-type strains but they were normally accepted by mecillinam-resistant derivatives and by cya and crp mutants, which, unlike the corresponding Escherichia coli strains, did not display resistance to mecillinam. On the other hand, the divD insertion could be efficiently transduced to any strain. It is concluded that the rodA, mre, and divD genes are involved in the control of rod cell shape but, in addition, the RodA and Mre products perform some function(s) that is essential for wild-type cells but dispensable for some mecillinam-resistant strains, and for cya and crp mutants.     

Interactions between nitrate and ammonium during uptake by carob seedlings and the effect of the form of earlier nitrogen nutrition

Seedlings of carob ( Ceratonia siliqua L. cv. Mulata) were used in two sets of experiments in order to evaluate; (1) the reciprocal effects of each nitrogen form on net uptake of nitrate and ammonium, and (2) the effect of earlier nitrogen nutrition on ammonium versus nitrate uptake. In the former group of experiments we studied the kinetics of nitrate and ammonium uptake as well as the interference of each of the two forms with net uptake of ammonium and nitrate by both nitrogen depleted and nitrogen fed carob seedlings. On the whole, nitrogen depletion led to increase in both affinity and V_max of the system for both forms of nitrogen, at the same time as the effects of nitrate on uptake of ammonium and vice versa were concentration dependent. In the second group of experiments the effects of earlier nitrogen nutrition on nitrate and ammonium uptake were characterized, and in this case we observed that: (a) if only one form of N was supplied, ammonium was taken up in greater amounts than nitrate; (b) the presence of ammonium enhanced nitrate uptake; (c) ammonium uptake was inhibited by nitrate; (d) there was a significant effect of the earlier nitrogen nutrition on the response of the plants to a different nitrogen source. The latter was evident mainly as regards ammonium uptake by plants grown in ammonium nitrate. The interactions between nitrate and ammonium uptake systems are discussed on the basis of the adaptation to the nitrogen source during early growth.     

Interval mapping of quantitative trait loci for reproductive,morphological, and seed traits of soybean (Glycine max L.)

Quantitative trait loci (QTL) were mapped in segregating progeny from a cross between two soybean (Glycine max (L.) Merr.) cultivars: Minsoy (PI 27.890) and Noir 1 (PI 290.136). The 15 traits analyzed included reproductive, morphological, and seed traits, seed yield and carbon isotope discrimination ratios (¹³C/¹²C). Genetic variation was detected for all of the traits, and transgressive segregation was a common phenomenon. One hundred and thirty-two linked genetic markers and 24 additional unlinked markers were used to locate QTL by interval mapping and one-way analysis of variance, respectively. Quantitative trait loci controlling 11 of the 15 traits studied were localized to intervals in 6 linkage groups. Quantitative trait loci for developmental and morphological traits (R1, R5, R8, plant height, canopy height, leaf area, etc.) tended to be clustered in three intervals, two of which were also associated with seed yield. Quantitative trait loci for seed oil were separated from all the other QTL. Major QTL for maturity and plant height were linked to RFLP markers R79 (31% variation) and G173 (53% variation). Quantitative trait loci associated with unlinked markers included possible loci for seed protein and weight. Linkage between QTL is discussed in relation to the heritability and genetic correlation of the traits.     

The metabolism of sugar and malic acid by Leuconostoc oenos: effect of malic acid, pH and aeration conditions

The co-metabolism of sugars by Leuconostoc oenos was studied under different environmental conditions. Under aerobic conditions, growth and sugar metabolism were poorer than under CO₂ or N₂ atmosphere and acetic acid accumulated to a larger extent. Glycerol was found in the aerobic cultures while erythritol was detected under N₂ or CO₂. When medium conditions make growth difficult (low pH, aerobic conditions, low nutrients), sugars were only slightly metabolized and growth was very slow while malic acid was rapidly and completely degraded, leading to an increase in the y _ATP. Aeration effects on the malic acid degradation rate depended on the nutrients and carbon source in the medium. Malic acid clearly stimulated bacterial growth, allowing an increase in the molar growth yields and ATP production. The results suggest that under adverse conditions cells are not able to grow and malic degradation supplies additional energy production.