Promotion by phloroglucinol of micropropagation of Minuartia valentina, an endangered and endemic Spanish plant

Tissue culture techniques for the propagation and conservation of endemic or threatened plants can be used to complement the methods usually applied in ex situ conservation. Thus, Minuartia valentina (Caryophyllaceae), an endangered plant species endemic to the Valencia Community (Eastern Spain), was successfully regenerated through shoot proliferation from wild plants growing in their natural area. Nodal segments, 10~mm long, were cut from rametes of adult material, sterilised and established in vitro. Equally successful shoot multiplication was achieved on Murashige and Skoog (MS) medium with 80 mg l-1 phloroglucinol in combination with either 1 mg l-1 6-benzylaminopurine or 1 mg l-1 kinetin. Excised shoots were rooted in MS medium supplemented with an auxin (indole acetic acid, indole-3-butyric acid, or napththalene acetic acid). Shoots rooted well (96–100%) within three weeks in all auxin treatments. However, the use of napththalene acetic acid was discarded because this auxin delayed root differentiation, and induced adventitious root malformation. Rooted plantlets were transferred to pots and 85% of them acclimatized successfully four weeks after transfer to greenhouse conditions, where they exhibited normal morphology and growth.     

Identification of the coding region for the putidaredoxin reductase gene from the plasmid of Pseudomonas putida

The first 12 NH₂-terminal amino acids of the Pseudomonas putida putidaredoxin reductase were shown to be Met-Asn-Ala-Asn-Asp-Asn-Val-Val-Ile-Val-Gly-Thr. Comparison of these data with the DNA sequence of the BamHI-HindIII 197-base fragment derived from the PstI 2.2-kb fragment obtained from the P. putida plasmid showed that the putidaredoxin reductase gene was downstream from the cytochrome P-450 gene and the intergenic region had the 24-nucleotide sequence TAAACACATGGGAGTGCGTGCTAA. The Shine-Dalgarno sequence GGAG was detected in this region. The initiating triplet for the reductase gene was GTG, which normally codes for valine, but in the initiating codon position codes for methionine. From the amino acid sequence and X-ray data comparisons with other flavoproteins, what appears to be the AMP binding region of the FAD can be recognized in the NH₂-terminal portion of the reductase involving residues 5–35.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Mitogenic Activity of Cytoplasmic Membranes Isolated from L-Forms of Staphylococcus aureus

Cytoplasmic membranes of L-forms of Staphylococcus aureus exerted a strong mitogenic effect on splenocytes of athymic nude mice as well as normal mice, while a cytoplasmic fraction of the same bacteria did not show definite mitogenicity. The mitogenic principle(s) of the membrane fraction was resistant to treatment with trypsin and was heat stable (at 100 C for 10 min). The active principle(s) in the insoluble residue of the membrane fraction digested with trypsin was not extracted with cold acetone, but could be solubilized by extraction with a cold chloroform-methanol mixture (2:1, v/v). The mitogenic principle(s) in the extract was fractionated by silicic acid column chromatography. Among five fractions separated by chromatography, fractions eluted with chloroform-methanol mixtures (1:1 and 1:20, v/v) were found to be strongly mitogenic. The cytoplasmic membranes of the L-forms also exerted a definite mitogenic effect on guinea pig splenocytes, but not on the thymocytes.     

Evolutionarily stable seasonal timing for insects with competition for renewable resource

Summary I study the evolutionarily stable seasonal patterns of hatching and pupation for herbivorous insects that engage in exploitative competition for a renewable resource. A longer larval feeding period enhances female fecundity, but also causes a higher mortality by predation and parasitism. Previously, it was shown that the evolutionarily stable population exhibits asynchronous starting and ending of the larval feeding period in a model in which larval growth rate decreases with the total larval biomass in the population due presumably to interference competition. Here I study the case in which resource availability changes not only with environmental seasonality but with the depletion by the feeding of larvae. I find that if the impact of the herbivory is strong, both hatching and pupation should occur asynchronously in the evolutionarily stable population. And if the favourable season for the host plant is short the ESS population may include synchronous timing of pupation. If the timing of hatching and pupation occurs asynchronously, in the first day of each interval some fraction of the population hatch or pupate, respectively and the rest do so gradually over the interval. In addition, if the environmental variable changes as a symmetric function of time, the length of the period in which hatching occurs tends to be much shorter than the period in which pupation occurs.     

Isobutene production by Rhodotorula minuta

Summary Isobutene production by Rhodotorula minuta IFO 1102 was studied. It was confirmed that the gas species produced by this yeast was isobutene from the result of analysis with a gas chromatograph mass spectrometer. Oxygen supply was essential to the microbial production of isobutene. The optimum pH was found to be approximately pH 6.0 and optimum temperature 25°–27° C. Isobutene production rate was maximal when l-leucine and l-phenylalanine in the medium were being uptaken by the yeast.The results from an investigation of the role of l-leucine and l-phenylalanine suggested that l-leucine was the precursor of isobutene and l-phenylalanine the inducer for the enzyme concerned with isobutene production.     

Antibody-dependent cell-mediated cytotoxicity using a murine monoclonal antibody against human colorectal cancer in cancer patients

Summary Antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by a murine monoclonal antibody against human colerectal carcinoma, antibody 19–9, with human effector cells was tested in 33 patients with various carcinomas, 16 patients with benign lesions, and 13 normal controls, using a 12-h ⁵¹Cr release assay using human colorectal cancer cells as targets. Peripheral blood mononuclear cells (PBM) from these groups of patients and normal controls achieved moderate levels of target cell lysis in the presence of the monoclonal antibody at the high effector to target cell ratio of 200:1. The ADCC activity of PBM in cancer patients was significantly higher than that in either normal persons or patients with benign lesions. Since the ADCC was shown to be mainly mediated by adherent monocytes in the PBM, ADCC activity of monocytes from cancer patients was compared to those from control groups at an effector to target cell ratio of 30:1. The results also showed that the lytic capacity of monocytes was significantly higher in cancer patients than that in the control populations.     

Unusual solvent effect on protease activity and effective optical resolution of amino acids by hydrolytic reactions in organic solvents

Summary The catalytic activities of -chymotrypsin, subtilisin Carlsberg, and subtilisin BPN' for hydrolysis of amino acid esters in acetonitrile-water were unusually dependent on the solvent composition. The products obtained as precipitates in high concentrations of acetonitrile were L-amino acids of high optical purities, and effective optical resolution of amino acids was achieved.     

Preparation and properties of the water-soluble chlorophyll-bovine serum albumin complexes

By mixing chlorophyll (Chl) a or b with a dense bovine serum albumin solution, the water-soluble Chl-bovine serum albumin complexes were prepared. These complexes, eluted near the void volume on a gel filtration, were separated well from unreacted bovine serum albumin, indicating an aggregation of such molecules in the complexes. Preparation of chlorophyllide (Chlide) a- or Chlide b-bovine serum albumin complex was unsuccessful, while the phytol-, and β-carotene-bovine serum albumin complexes could be obtained. Chls in the Chl-bovine serum albumin complexes had the following characteristics. (i) Main absorption peak of Chl a or b in the red region occurred at 675 nm or 652 nm, respectively. The Chl a-bovine serum albumin complex having absorption peak at 740 nm was also prepared. As compared with the stabilities of Chl a and b in Triton X-100. (ii) Both Chls in the bovine serum albumin-complexes were stable against oxidative stresses, such as photobleaching, Fenton reagent, peroxidase-H₂O₂ system. But (iii) they were easily hydrolyzed by chlorophyllase. These properties of Chls in the bovine serum albumin-complexes were similar to those of Chls in the isolated light-harvesting Chl a/b protein complex. A possible localization of Chls within the bovine serum albumin complexes was suggested that the porphyrin moiety of Chl was buried in bovine serum albumin; however, the hydrophilic edge of porphyrin ring, adjacent to the phytol group, occurred in the hydrophilic region of a bovine serum albumin molecule.