Interspecies recombination In nature: a meningococcus that has acquired a gonococcal PIB porin

A. vaginal isolate of Neisseria has been reported to resemble Neisseria meningitidis in biochemical characteristics but to react with serological reagents that are specific to the PI porin from Neisseria gonorrhoeae. We have confirmed that this isolate has the biochemical attributes of a meningococcus and have shown that it clusters among meningococcal Isolates on a dendrogram based on isoenzyme variation within housekeeping enzymes from populations of N. meningitidis and N. gonorrhoeae. Furthermore, the sequences of the fbp and adk genes were typical of those of N. meningitidis and were distinct from those of N. gonorrhoeae. However, the porB gene was very similar to the por genes of N. gonorrhoeae isolates that express the PIB class of outer-membrane porin (differing from one gonococcal por allele at only a single nucleotide site), and was clearly distinct from the porB genes of N. meningitidis. The isolate therefore appears to be a typical meningococcus, except that its porB gene has been replaced with the por gene from a gonococcus.     

Synthesis of new azino fused benzimidazolium salts. a new family of DNA intercalating agents. I

A series of new pyrido[1,2-a]- and pyridazino[1,6-a]benzimidazolium salts have been synthesized from readily available 1,3-disubstituted 2-alkylbenzimidazolium salts. Their affinity to DNA and in vitro cytotoxicity versus HT-29 have been tested. The initial results show that the title compounds are a new family of intercalating agents.     

Yeast invertase: Subcellular distribution and possible relationship between the isoenzymes

The intracellular invertase ofSaccharomyces cerevisiae is mainly found in a soluble form (91–95%), while only minor amounts are found bound to the internal (4–8%) and plasma membranes (less than 1%). In the processes of derepression or repression, inhibition of RNA or protein synthesis, or in the presence of 2-deoxy-d-glucose, the levels of the membrane-bound and external activities are modified in a way in which their relation is clear, while the soluble enzyme does not change at all. These results, together with the fact that the membrane-bound and the external enzymes are glycoproteins, suggest a precursor-product relationship between the enzymic forms.     

Isolation and properties of crystalline ferredoxin from lactuca sativa

Lettuce ferredoxin has been purified to homogeneity, with a yield of 18 mg/kg of denerved leaves. It crystallizes in magnificent needles, often clustered in broom-like sheaves. The absorption spectrum showed maxima at 460, 422, 330 and 274 nm,with a ratio A₄₂₂/A₂₇₄, of 0.46. The mM absorption coefficient was 9.74 at 422 nm, and 21.62 at 274 nm. This ferredoxin showed a pI = 4.7 and an E′₀ = ?425 mV (at pH = 7.7). MWs of 12 400, 11480 and 13000 were obtained by sucrose gradient centrifugation, and on the basis of the amino acid composition and the iron content, respectively, with an average of 12 300. The amino acid analysis showed the existence of one methionine residue per mole, with 105 amino acid residues. There are two iron atoms and two labile sulfide groups per mole; 4 half-cystine residues were found by performic acid oxidation, and 5 cysteine groups when determined by titration with pHMB. The native protein is not fixed on thiol-Sepharose 4B, but it is quantitatively retained after incubation with 8 M urea. Lettuce ferredoxin showed a 62, 58 and 78% effectiveness with the spinach ferredoxin-NADP reductase, nitrite reductase and fructose-1,6-diphosphatase (FDPase), respectively, when compared with the spinach ferredoxin. This different behaviour of both ferredoxins is joined to genetic-structural relationships, and suggests that the role of ferredoxin in FDPase activation is more sophisticated than that of a mere nonspecific reductant.     

DIASTOLIC OPENING OF THE AORTIC VALVE (AV) IN A CASE OF AORTIC INSUFFICIENCY DUE TO AV FENESTRATION

A patient with severe aortic insufficiency due to fenestration of the non-coronary aortic valve leaflet is described. A preoperative echocardiogram demonstrated early closure of the mitral valve and early diastolic separation of the aortic valve leaflets. These findings disappeared after partial surgical correction and subsequent hemodynamic improvement. Premature opening of the aortic valve is common in severe aortic insufficiency.     

β-Carotene, vitamin C and vitamin E content of the marine microalga Dunaliella tertiolecta cultured with different nitrogen sources

Variations in the β-carotene, vitamin C and vitamin E content of D. tertiolecta have been shown to result from the nitrogen source used in the culture medium. Differences of 101%, 38% and 69% have been found in β-carotene, ascorbic acid and tocopherol content in mg/g of dry matter, respectively, and differences of 147%, 63% and 37% occurred in β-carotene, vitamin C and E concentrations in mg/litre of culture, respectively. Considering the β-carotene, vitamin C and vitamin E content in mg/g of chlorophyll a, maximum variations occurred in β-carotene content, with differences of 145% among the different nitrogen sources. Maximum β-carotene and vitamin C values were found in urea cultures, whereas urea cultures showed the minimum values for vitamin E.     

A NEW SPECIES OF BEAKED WHALE MESOPLODON PERUVIANUS SP. N. (CETACEA: ZIPHIIDAE) FROM PERU

Mesoplodon peruvianus , a new species of beaked whale, is described on the basis of ten specimens which have either stranded or been captured between 11°12'S and 15°19'S latitude along the coasts of the provinces of Lima and Ica, south central Peru. This is the thirteenth living species of Mesoplodon recognized in the world's oceans. The animals that were examined were uniformly gray above, shading to lighter gray below. This whale is the smallest species of Mesoplodon (maximum body length 3.72 m) and is characterized by its teeth, which are small (31 to 65 mm long), ovate in cross section, and positioned 2.5% to 8.4% of the mandibular length from the anterior extremity, and posterior to the mandibular symphysis.     

3H-noradrenaline metabolism in the isolated epididymal and prostatic portions of the rat vas deferens

The spontaneous ³H-noradrenaline efflux from the isolated epididymal and prostatic portions of the rat vas deferens, was investigated. The spontaneous tritium efflux was higher in the epididymal portion than in the prostatic one from normal animals. Such differences were abolished after castration. On the other hand, acetylsalicylic acid enhanced the total tritium efflux only in the epididymal portion, whereas phentolamine and phenoxybenzamine increased the total tritium efflux from the two portions of the rat vas deferens in both experimental groups. The prostatic portion released a similar amount of ³H normetanephrine than the apididymal end, whereas other metabolic fractions (3,4-dihydroxyphenylglycol; 3,4-dihydroxymandelic acid and O-methylated deaminated metabolites) were smaller in the prostatic portion in comparison with the epididymal portion from control vas deferens. The results presented in the isolated rat vas deferens suggest the existence of a prostaglandin as well as an alpha adrenoceptive modulation of the spontaneous total tritium efflux.     

Gene expression in normal and virally transformed mouse 3T3B and hamster BHK21 cells

Cell lines 3T3B (mouse), 3T3B-SV40, BHK21 (hamster) and BHK21 polyoma virus (PyY) were labelled with [³⁵S]methionine under conditions in which 500–600 cpm were incorporated per cell during a 20 h incubation period. Two-dimensional gel electrophoresis analysis of the total [³⁵S]methionine-labelled polypeptides from 200–300 cells followed by fluorography revealed about 500 acidic (isoelectric focusing, IEF) and 150 basic polypeptides (non-equilibrium pH gradient electrophoresis, NEPHGE) whose position could be reproducibly assessed. Counting of 33 abundant acidic polypeptides present in both 3T3B and 3T3B-SV40 revealed significant changes in the relative proportion of ten of them. Seven, including the subunit of the 100 Å filaments ‘fibroblast type’ (55K) (1.1% in 3T3B; 0.6% in 3T3B-SV40), three cytoarchitectural proteins and three soluble proteins, corresponded to a decrease of 40% or more in the radioactivity of the spots in transformed cells, and only in three cases was there a significant increase in radioactivity of polypeptides in 3T3B-SV40 cells. Among the polypeptides that show less than 40% variation we have identified total actin (42K) (13% of total label in 3T3B; 10% in 3T3B-SV40), α- and β-tubulin (55K) (1.6% of total label in 3T3B; 2% in 3T3B-SV40), eleven polypeptides present in Triton skeletons, and nine soluble proteins. We have also observed 25 obvious changes in polypeptide intensities (16 acidic and 9 basic) but these were not quantitated. Only three polypeptides were found in transformed cells that were not detected in normal cells. One of these corresponded to the large T antigen and the other two to Triton-soluble proteins of a molecular weight in the range of 52–54K. Similar quantitative studies on the hamster BHK21/BHK21PyY pair confirmed at least the major observations made in 3T3B and 3T3B-SV40.