Relationship between carbon monoxide dehydrogenase and a small plasmid in Pseudomonas carboxydovorans

Abstract Isolation of plasmid DNA followed by plasmid curing was carried out to examine the relationship of plasmid to carbon monoxide dehydrogenase (CO-DH) production in carboxydobacteria. A small plasmid of almost identical size (1.52−1.76 × 10⁶) was present in Pseudomonas carboxydovorans, Azotobacter sp.1, and Azomonas sp.2. Azomonas sp.1 contained two kinds of plasmids (1.5 × 10⁶ and 2.47 × 10⁶). No plasmids were found in Pseudomonas carboxydohydrogena , JC1, and HY1. A plasmid-cured clone of P. carboxydovorans was obtained by growing the cells at 37°C. The cured cell was able to grow CO autotrophically on solid, but not in liquid, medium. CO-DH of the cured cell was active and consisted of three subunits similar to those found in the wild-type enzyme, with the exception that the β subunit of the enzyme was larger than that of the wild-type enzyme. These results suggest that the small plasmids do not carry genes encoding CO-DH but may have gene(s) for processing the β subunit of the enzyme.     

Comparison of the antiemetics metoclopramide and promethazine in labour.

A double blind trial was conducted in 477 mothers in labour to compare the antiemetics metoclopramide 10 mg and promethazine 25 mg and placebo when added to the first dose of pethidine. Metoclopramide and promethazine were equally effective, and both better than placebo, in reducing the incidence of nausea and vomiting after the administration of pethidine. Seventy seven per cent of mothers were drowsy, and 8% slept in the hour after the pethidine injection, with no difference between the groups. The sedative effect was more persistent in the promethazine group, 66% of whom were still drowsy after delivery. One third of the mothers in each group needed further analgesia, with 77% of these ultimately requesting an epidural. The reduction in pain half an hour and one hour after pethidine, assessed by a visual analogue scale, were, respectively, 22% and 22% for placebo; 26% and 23% for metoclopramide; 13% and 9% for promethazine. Analgesia after metoclopramide was significantly better than that after promethazine in terms of pain score, duration of first injection, and need for Entonox. Metoclopramide is therefore to be preferred to promethazine as an antiemetic in labour.     

The nucleotide sequence of the RAD3 gene of Saccharomyces cerevisiae: a potential adenine nucleotide binding amino acid sequence and a nonessential acidic carboxyl terminal region.

The RAD3 gene of Saccharomyces cerevisiae is required for excision of pyrimidine dimers and is essential for viability. We present the nucleotide sequence of the RAD3 protein coding region and its flanking regions, and the deduced primary structure of the RAD3 protein. In addition, we have mapped the 5' end of RAD3 mRNA. The predicted RAD3 protein contains 778 amino acids with a calculated molecular weight of 89,779. A segment of the RAD3 protein shares homology with several adenine nucleotide binding proteins, suggesting that RAD3 protein may react with ATP. The twenty carboxyl terminal amino acids of RAD3 protein are predominantly acidic; however, deletion of this acidic region has no obvious effect on viability or DNA repair.     

Instability kinetics of trp operon plasmid ColEl-trp in recombinant Escherichia coli MV 12[pVH5] and MV 12trp R [pVH5

In studying plasmid instability in recombinant microorganisms, Escherichia coli MV 12[p VH5] and MV 12 trpR[p VH5] harboring trp operon were used as experimental model systems. The host with the trp repression system was partially derepressed by 3-beta-indoleacrylic acid. The results from kinetic analysis of plasmid instability showed that the stability of p VH5 and the growth rate of MV 12[p VH5] decreased rapidly in presence of 3-beta-indoleacrylic acid at a concentration higher than 10 mug/mL, but beyond 30 g/mL no significant change was observed. This suggests that Trp(-) variants from MV 12[p VH5] could be produced from the host cells at a different frequency depending on the physiological condition. In another system, MV 12 trpR[p VH5] which was constructed by conjugation of E. coli MV 12[p VH5] with E. coli CSH61, the plasmid stability was much lower and the frequency of Trp(-) cell production was about 10 times higher as compared with the MV 12[p VH5] when treated with 3-beta-indoleacrylic acid. A kinetic model representing the plasmid instability was derived, and a fairly good agreement with the experimental results was found. The fraction of plasmid-free cell (or negative variant) shows a different time course profile depending on the segregation coefficient (a, production rate of negative variants from positive cells during one generation), growth ratio (G, the ratio of growth rates of negative variants to positive cells), and other parameters. The negative variant fraction continues to increase ("run away" type) or it approaches to a finite value ("settling" type) depending on the relative values of a and G.     

Populational dynamics of three annual species of alpine plants in the Rocky Mountains

Summary Survivorship, fecundity, and seed bank size were measured over two years in alpine populations of the annuals, Koenigia islandica, Polygonum confertiflorum, and P. douglasii. The major loss of individuals from all populations occurred between seed dispersal and germination. Survival of vegetative plants to maturity was high in all species, usually above 80%, and the average number of seeds produced per plant was less than 10 in all species in both years. Seed banks existed for all three species but were small since more than 80% of the viable seeds in the soil germinated in the spring. Both survival and fecundity were negatively correlated with density in P. confertiflorum. These patterns of population dynamics are similar to those found in many annuals of temperate environments.     

Papovaviral sialoadenitis in athymic nude rats

A wasting disease was found in 32 athymic nude rats. The rats had parotid sialoadenitis with intranuclear inclusion bodies in ductal and acinar epithelial cells. Other common lesions included bronchitis, bronchiolitis and secondary bacterial pneumonia. Less commonly, rhinitis and Harderian adenitis were seen. Intranuclear inclusions were also seen in bronchial epithelium of 1 rat, Harderian gland acini of 1 rat and laryngeal glands of 2 rats. Viral particles, averaging 45 nm in diameter, sometimes in crystalline arrays, were found in the nucleus of parotid epithelial cells. By the use of the avidin-biotin-peroxidase complex (ABC) immunoperoxidase technique, antibodies to disrupted SV40 virus (the group specific antigen of the polyomavirus (miopapovavirus) genus of the papovavirus family) reacted with intranuclear inclusions and cytoplasm of parotid epithelium and inclusions in lung and Harderian gland. The viral antigen did not cross react with antibodies to mouse polyoma, mouse K or disrupted bovine papilloma viruses.     

Calcium transients during early development in single starfish (Asterias forbesi) oocytes

Maturation and fertilization of the starfish oocyte are putative calcium-dependent events. We have investigated the spatial distribution and temporal dynamics of this calcium dependence in single oocytes of Asterias forbesi. We used the calcium photoprotein, aequorin, in conjunction with a microscope-photomultiplier and microscope-image intensifier. Surprisingly, in contrast to earlier work with Marasthenias glacialis, there is no detectable increase in intracellular-free calcium in the oocyte of A. forbesi in response to the maturation hormone 1-methyl adenine. During fertilization of the same, matured, A. forbesi oocyte there is a large increase in intracellular-free calcium. The calcium concentration increases to approximately 1 microM at the point of insemination and the region of elevated free calcium expands across the oocyte in approximately 20 s (17-19 degrees C). After the entire oocyte reaches an elevated concentration of free calcium, the concentration decreases uniformly throughout the oocyte over the next several minutes.     

Nonoccluded baculovirus- and filamentous virus-like particles in the spotted cucumber beetle,diabrotica undecimpunctata (coleoptera: chrysomelid)

Nonoccluded baculovirus-and filamentous virus-like particles were found in nuclei of hemocytes or midgut cells of field-collected spotted cucumber beetles. Each type of particle was associated with a different type of virogenic stroma containing various viral components similar to those referred to as capsid, nucleocapsid, viroplasm, and viral envelope in other known baculovirus infections. Nucleocapsids of the virus which occured only in hemocytes were rod-shaped particles approximately 230 nm long and 52 nm wide and were enveloped singly by a trilaminar unit membrane. Enveloped and partly enveloped particles appeared to be released from the nucleus to the cytoplasm by budding through the nuclear envelope acquiring additional membranes. The nucleocapsids of the virus which occurred only in nuclei of midgut cells were filamentous particles with an average diameter of 25 nm and variable length up to 2 μm. Some extremely long particles were bent almost 360° near the middle, resulting in a hairpin-like configuration. The particles were always enveloped singly. No particles budding through the nuclear envelope were observed.     

A species difference between hamster and rat in the effect of oestrogens on growth of large preantral follicles

Intact or hypophysectomized 23-day-old hamsters and rats were injected s.c. with 2 mg diethylstilboestrol (DES) or 1 mg oestradiol cyclopentylpropionate (OECP) on Days 23-25 and killed on Day 26. Although serum oestradiol was elevated to the same high levels by OECP, ovarian and uterine weights were increased in the rat by OECP or DES whereas only the uterus responded in the hamster. This correlated with the ability of the oestrogens to increase significantly the number of large preantral and antral follicles in the intact rat but only the number of follicles with 2-3 layers of granulosa cells in the immature hamster. Qualitative study revealed that DES and OECP increased the number of large preantral follicles in the adult hypophysectomized rat but were ineffective in the adult hamster. It is concluded that for the immature and adult hamster oestrogens do not play a major role in the recruitment of large preantral follicles.     

Natural killer activity in the rat. III. Characterization of transplantable large granular lymphocyte (LGL) leukemias in the F344 rat

Six transplantable large granular lymphocyte (LGL) tumor lines in F344 rats were examined for natural killer (NK) and antibody-dependent cell-mediated cytotoxicity. Tumor cells from all six lines were highly cytotoxic, even at low effector to target ratios, when tested against NK-susceptible targets, but were unreactive against an NK-resistant target (C58NT)D) and a macrophage-susceptible target (P815). Three lines showed significant levels of lysis against antibody-coated tumor cells. After in vivo transplantation, the levels of cytotoxicity steadily increased in three lines and decreased in one. The cytotoxic activity of one line (RNK-16) remained high through 12 transplant generations. Tumor cells injected i.p. spread via the lymphatics to regional lymph nodes, mediastinal nodes, blood, and eventually the bone marrow. Leukemia occurred concurrently with organ enlargement and increased levels of NK. Studies in (F344 X W/Fu)F1 rats clearly demonstrated that the cytotoxic cells from leukemic animals were the transplanted tumor cells themselves and not merely the activation of normal host LGL. These results demonstrate that naturally occurring, transplantable LGL leukemias are an easily obtainable and excellent source of materials for those studies requiring a large number of functionally active LGL.