Selective production of glutamate by an immobilized marine blue-green alga,Synechococcus sp.

Summary Among 200 strains of marine bluegreen algae isolated from the coastal areas of Japan, the marine blue-green alga Synechococcus sp. NKBG 040607 excreted glutamate at the highest rate, 82.6% of total amino acids production being glutamate. Synechococcus sp. NKBG 40607 was immobilized in calcium alginate gel. Glutamate production by immobilized cells was double that of native cells. Maximal glutamate production (25 g/cm³ gel per day) of the immobilized cells was observed under a light intensity of 144 Einstein/m² per second at a cell concentration of 7.5 mg dry cells/cm³ gel. Immobilized cells of Synechococcus sp. can use nitrate as a nitrogen source. Immobilized marine Synechococcus sp. produced 0265 mg/cm³ gel of glutamate for 7 days in the presence of chloramphenicol.     

Oxygen uptake rate of immobilized growing hybridoma cells

Summary The specific oxygen uptake rate of hybridoma cells immobilized in calcium alginate gel particles was measured, and the observed data was compared with those of non-immobilized cells. The uptake rate of the immobilized cells coincided with that of the non-immobilized hybridoma cells just after immobilization, but increased with cell growth. On the other hand, the cellular glucose consumption rate decreased slightly during the experiments. The increased oxygen uptake rate by immobilized cells was closely related to the formation of cell colonies in the gel particles.     

Evidence for the location of foreign genes in three different chromosomes in a plant obtained from direct DNA transfer

Tobacco mesophyll protoplasts were treated with plasmids, pCT2 (17.1 kbp) or pCT2T3 (18.3 kbp), which contained a chimeric aminoglycoside phosphotransferase II (APH(3′)II) gene and an intact nopaline synthase gene. Expression of two marker enzymes, APH(3′)II and nopaline synthase, were analyzed in transformed plants. Four out of 16 transformants obtained by pCT2T3 possessed both enzymes. Upon self-pollination, the progeny of one of transformants (T2) segregated to 153∶4 in terms of resistant and susceptible character to kanamycin, suggesting insertion of foreign genes into three independent chromosomes. The kanamycin resistant character in the rest of transformants showed 3∶1 segregation. DNA blot analysis of the T2 transformant and progenies indicated the presence of two marker genes.     

Spawning behavior and early life history of the sharpnose puffer,Canthigaster rivulata,in the aquarium

Specimens ofCanthigaster rivulata (Temminck et Schlegel) were collected from Kominato and Hayama, central Japan, from May, 1985 to October, 1986. On the basis of the gonadosomatic index, gonadal histology and results of artificial fertilization of these specimens, the spawning season is considered to extend from late June to mid-September. The specimens exhibited the following dimorphic differences associated with sex: 1) The male is larger than the female. 2) Ventral side of the body is brownish orange in the male with vermiculated or reticulated patterns of bright violet, while it is white in the female. 3) The male has a well-developed skin fold along the mid-dorsal and mid-ventral lines, which is greatly elevated during courtship; whereas the female’s skin folds are not or slightly developed and conspicuous only during courtship. In an aquarium with the water temperatures of 22 to 26°C, a pair of fish spawned every four days late in the morning for three consecutive months. Courtship and spawning occurred in a pair. The male swam in front of the female, and elevated the skin folds both dorsally and ventrally, fully spreading the unpaired fins, with the ventral side of the body flashing bright blue and the dorsal side turning dark. Both fish swam in a circular fashion, elevating the skin folds. The male followed the female nudging her abdomen with his snout. Both fish turned upward, and released gametes. The eggs are spherical, 0.53–0.73 mm in diameter, demersal, adhesive, transparent, and pale yellowish orange in color, and contain a cross-shaped or asteroid cluster of oil globules. The egg membrane was thick and consisted of about 14 concentric layers. The incubation period ranged from 73.5 hours at 28.2–28.5°C to 145.0 hours at 22.1–22.4°C. The newly hatched larvae were 1.38–1.98 mm in total length (TL) with 84-11-13 = 19–21 myomeres. The yolk was absorbed when the larvae attained 1.49–2.22 mm TL, three days after hatching. The larvae were fed on oyster larvae, blue mussel larvae, sea-urchin larvae and rotifers, but all of them died in 16 days. During the embryonic and early larval stages, the only pigment cells that appeared on the body were the black chromatophores.     

The origin of the luteinizing hormone-releasing hormone (LHRH) neurons in newts (Cynops pyrrhogaster): the effect of olfactory placode ablation

Summary Neurons containing luteinizing hormone-releasing hormone (LHRH) are first detected in newt embryos (Cynops pyrrhogaster) in the olfactory epithelium and ventromedial portion of the olfactory nerve, after which they sequentially appear in the intracerebral course of the terminal nerve at prometamorphosis, and in the septo-preoptic area at postmetamorphosis. In adults, however, LHRH-immunoreactive cells are rarely seen in the nasal region, and their distribution shifts into the brain, suggesting their migration. In order to ascertain the origin and possible migration route of these neurons in newt larvae, the effect of unilateral or bilateral olfactory placodectomy on the LHRH neuronal system has been studied. Removal of the olfactory placode results in the absence of LHRH-immunoreactive cells in the nasal and brain regions of the operated side, whereas the subsequent growth and the LHRH-immunoreactive cellular distribution in the contralateral side are identical to those of normal larvae. Following bilateral placodectomy, no LHRH immunoreactivity is detected on either side of the olfactory-brain axis. These results suggest that LHRH neurons of the newt, Cynops pyrrhogaster, originate in the olfactory placode and then migrate into the brain during embryonic development.     

Role of cell-mediated immunity in the resistance to experimental sporotrichosis in mice

The in vitro activity of several new imidazoles, cloconazole, sulconazole, butoconazole, isoconazole and fenticonazole, were compared with those of amphothericin B, flucytosine, and three azoles: econazole, miconazole and ketoconazole against isolates of pathogenic Candida. A total of 186 clinical isolates of 10 species of the genus Candida and two culture collection strains were tested by an agar-dilution technique. Isoconazole was the most active azole, followed by butoconazole and sulconazole. Differences between some of the species in their susceptibility to the antifungal agents were noted. Sulconazole and cloconazole had the highest activity in vitro against 106 isolates of C. albicans. Butoconazole and isoconazole were also very active against isolates of C. albicans, and were the most active azole compounds against 80 isolates of Candida spp.     

Phenol-treatment and a homologous pairing-assay.

Homologous pairing is a key step in homologous genetic recombination. In the early stage of trials for the identification of homologous pairing-promoting proteins from a fission yeast, Schizosaccharomyces pombe, we treated DNA products with phenol in the presence of a salt for the removal of tightly bound proteins from DNA before the assay, but we found that this treatment caused very efficient protein-independent double-strand formation from complementary single-stranded DNAs. Using an assay including the phenol treatment, we detected another species of apparent homologous pairing-promoting proteins in the nuclei, in addition to a homologous pairing-promoting protein consisting of three components which we reported previously. However, studies involving the use of an assay without the phenol-treatments revealed that the second one was not really a homologous pairing-protein. Thus, the protein-independent double-strand formation by phenol-treatment in the presence of a salt could cause the erroneous identification of homologous pairing-promoting proteins.