Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids

Buono, F. (Syracuse University, Syracuse, N.Y.), R. Testa, and D. G. Lundgren. Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids. J. Bacteriol. 91:2291-2299. 1966.-Growth and sporulation were studied in Bacillus cereus by use of an active culture technique and a synthetic medium. A high level of glutamic acid (70 mm) was required for optimal growth and glucose oxidation followed by sporulation even though relatively little glutamic acid was consumed (14 mm). Optimal growth occurred with a combination of 14 mm glutamic acid and 56 mm (NH(4))(2)SO(4), aspartic acid, or alanine. Ornithine or arginine at 70 mm could replace glutamic acid in the synthetic medium without affecting the normal growth cycle. Glutamic acid was not replaced by any other amino acid, by (NH(4))(2)SO(4), or by a combination of either alpha-ketoglutarate or pyruvate plus (NH(4))(2)SO(4). Enzyme assays of cell-free extracts prepared from cells harvested at different times were used to study the metabolism of glutamic acid. Glutamic-oxaloacetic and glutamic-pyruvate transaminases were completely activated (or derepressed) during early stages of sporulation (period of 6 to 8 hr). Alanine dehydrogenase responded in a similar manner, but the levels of this enzyme were much higher throughout the culture cycle. Neither glutamic dehydrogenase nor alpha-ketoglutarate dehydrogenase was detected. Sporulation in a replacement salts medium was studied with cells harvested at different times from the synthetic medium. Cultures 2 to 6 hr old were unable to sporulate in the replacement salts medium unless glutamic acid (7.0 mm) was present. By the 6th hr, cells were in the early stages of sporulation, showing spore septa development. Cultures 8 hr old sporulated in the replacement salts medium. Other metabolic intermediates able to replace glutamic acid in the replacement salts medium were alanine, aspartic acid, and glutamine at equimolar concentrations. Also, ammonium ions in combination with pyruvic, oxaloacetic, alpha-ketoglutaric, or fumaric acid replaced glutamic acid. The likely role of these metabolites is discussed.     

Productivity and biochemical composition of <Emphasis Type="Italic">Tetradesmus obliquus</Emphasis> and <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis>: effects of different cultivation approaches

The present work evaluated biomass productivity, carbon dioxide fixation rate, and biochemical composition of two microalgal species, Phaeodactylum tricornutum (Bacillariophyta) and Tetradesmus obliquus (Chlorophyta), cultivated indoors in high-technology photobioreactors (HT-PBR) and outdoors both in pilot ponds and low-technology photobioreactors in a greenhouse in southern Italy. Microalgae were grown in standard media, under nitrogen starvation, and in two liquid digestates obtained from anaerobic digestion of agro-zootechnical and vegetable biomass. P. tricornutum, cultivated in semi-continuous mode in indoor HT-PBRs with standard medium, showed a biomass productivity of 21.0?±?2.3 g m^?2 d^?1. Applying nitrogen starvation, the lipid productivity increased from 2.3 up to 4.5?±?0.5 g m^?2 d^?1, with a 24 % decrease of biomass productivity. For T. obliquus, a biomass productivity of 9.1?±?0.9 g m^?2 d^?1 in indoor HT-PBR was obtained using standard medium. Applying liquid digestates as fertilizers in open ponds, T. obliquus gave a biomass productivity (10.8?±?2.0 g m^?2 d^?1) not statistically different from complete medium such as P. tricornutum (6.5?±?2.2 g m^?2 d^?1). The biochemical data showed that the fatty acid composition of the microalgal biomass was affected by the different cultivation conditions for both microalgae. In conclusion, it was found that the microalgal productivity in standard medium was about doubled in HT-PBR compared to open ponds for P. tricornutum and was about 20 % higher for T. obliquus.     

Distribution and conservation of mobile elements in the genus Drosophila

Essentially nothing is known of the origin, mode of transmission, and evolution of mobile elements within the genus Drosophila. To better understand the evolutionary history of these mobile elements, we examined the distribution and conservation of homologues to the P, I, gypsy, copia, and F elements in 34 Drosophila species from three subgenera. Probes specific for each element were prepared from D. melanogaster and hybridized to genomic DNA. Filters were washed under conditions of increasing stringency to estimate the similarity between D. melanogaster sequences and their homologues in other species. The I element homologues show the most limited distribution of all elements tested, being restricted to the melanogaster species group. The P elements are found in many members of the subgenus Sophophora but, with the notable exception of D. nasuta, are not found in the other two subgenera. Copia-, gypsy-, and F-element homologues are widespread in the genus, but their similarity to the D. melanogaster probe differs markedly between species. The distribution of copia and P elements and the conservation of the gypsy and P elements is inconsistent with a model that postulates a single ancient origin for each type of element followed by mating-dependent transmission. The data can be explained by horizontal transmission of mobile elements between reproductively isolated species.      

Assignment of human aldolase C gene to chromosome 17, region cen→q21.1

Summary The mapping of the gene coding for human aldolase C has been studied using a specific cDNA probe and genomic blots from a panel of human-hamster somatic cell hybrids. The results show that the aldolase C gene is on chromosome 17. In situ experiments have restricted the mapping to the region 17cenq21.1. Using the same panel of human-hamster somatic cell hybrids, we have confirmed the localization of aldolase A and B on chromosomes 16 and 9, respectively.     

Transient expression of RSVCAT in transgenic zebrafish made by electroporation.

We report the fish use of an exponential decay electroporation system to introduce foreign DNA into fertilized zebrafish embryos. The plasmid RSVCAT (Rous sarcoma viral promoter (RSV) upstream from the chloramphenicol acetyltransferase gene (CAT)) was linearized and introduced into fertile zebrafish embryos by electroporation no later than the four-cell stage. Conditions for the procedure were empirically derived, and 68% of the treated animals survived through hatching to at least 6 days after fertilization and well beyond. Dot-blot analysis on DNA extracted from individual hatching fry demonstrated that 65% of the animals tested carried the foreign construct. Enzyme assays on the soluble proteins of treated animals were positive for chloramphenicol acetyltransferase activity. These data demonstrate that the foreign construct was being transiently expressed in the developing tissues of the embryo. The simplicity of this technique will greatly enhance the ability to analyze gene promoter regulation in vivo in transgenic zebrafish. The ability of the electroporated DNA to integrate into the host genome and to generate stable lines of transgenic fish is discussed.     

A New Entodiniomorphid Ciliate,Troglocorys cava n. g., n. sp., from the Wild Eastern Chimpanzee (Pan troglodytes schweinfurthii) from Uganda

ABSTRACT. Troglocorys cava n. g., n. sp. is described from the feces of wild eastern chimpanzee, Pan troglodytes schweinfurthii, in Uganda. This new species has a spherical body with a frontal lobe, a long vestibulum, a cytoproct located at the posterior dorsal side of the body, an ovoid macronucleus, a contractile vacuole near the cytoproct, and a large concavity on the left surface of the body. Buccal ciliature is non‐retractable and consists of three ciliary zones: an adoral zone surrounding the vestibular opening, a dorso‐adoral zone extending transversely at the basis of the frontal lobe, and a vestibular zone longitudinally extending in a gently spiral curve to line the surface of the vestibulum. Two non‐retractable somatic ciliary zones comprise arches over the body surface: a short dorsal ciliary arch extending transversely at the basis of the frontal lobe and a wide C‐shaped left ciliary arch in the left concavity. Because of the presence of three ciliary zones in the non‐retractable buccal ciliature, the present genus might be a member of the family Blepharocorythidae, but the large left concavity and the C‐shaped left ciliary arch are unique, such structures have never been described from other blepharocorythids.     

Cardiovascular drift can occur without a concomitant increase in skin blood flow

Previous studies have suggested that increases in skin blood flow (SkBF) are the primary physiological mechanism responsible for cardiovascular drift during exercise in the heat. Most of these studies, however, used exercise bouts of 60 min in duration or less. The purpose of this study was to explore the possibility that during prolonged (> 60 min) exercise in the heat, cardiovascular drift can occur without a concomitant increase in SkBF. The subjects were five heat-acclimated female volunteers. Each subject completed a 6-h heat exposure (38^oC, 62% RH). Heart rate (HR), stroke volume (SV), and two independent measures of SkBF were obtained each hour. Cardiovascular drift occurred, as evidenced by a significant (p<0.05) 19% increase in HR and a significant 21% decrease in SV. Interestingly, however, SkBF plateaued by hour 2 and showed no further increase. Such results suggest that during prolonged exercise in the heat, when SkBF has reached very high values (>20 ml / 100 ml per min) and plateaued, cardiovascular drift can still occur.     

A survey of chlortetracycline concentration in feed and its residue in chicken egg in commercial layer farms

The worldwide increase in the use of antibiotics as an integral part of poultry and livestock production industry has recently received increasing attention as a contributory factor in the international emergence of antibiotic-resistant bacteria in human beings. To gauge the presence of the aforementioned scenario in the Indian context, a preliminary survey was conducted to assess the use of chlortetracycline (CTC) in 12 commercial layer farms and to quantify and confirm its residue in the egg. Samples of feed and eggs were collected at day 0 (prior to CTC addition), 3rd, 5th and 7th day during treatment and on the 9th and 14th day (2nd and 7th day after withdrawal of CTC) from each of the 12 commercial poultry farms studied. Concentration of CTC in feed was significantly (P<0.01) high on the 3rd, 5th and 7th day. On the 9th day and 14th day CTC concentration in feed was significantly (P<0.01) lower compared to the earlier 3 days studied. A highly significant difference (P<0.01) of the antibiotic residue in egg was observed in all the 5 days with high residual levels of CTC in egg. CTC in feed and its residue in egg were detected even on the 9th and 14th day respectively.