Production of high levels of acetoin in Saccharomyces cerevisiae wine yeasts is a recessive trait

P. ROMANO, G. SUZZI, R. MORTIMER AND M. POLSINELLI. 1995. A genetic study of acetoin production was performed on wild wine yeast strains of Saccharomyces cerevisiae producing different amounts of the compound. By using differences found in these strains as source of genetic variability, it was found that crosses between high and low acetoin producing strains yielded the low level in the hybrids, indicating the low production as a dominant trait. Tetrad analysis showed that high vs low acetoin production is segregated as a single gene.     

Induction of dominant lethality by x-rays in radiosensitive strain of yeast

X-Ray-survival curves of haploid, diploid, triploid and tetraploid yeast strains homozygous for the X-ray-sensitive mutation rad52 (previously xs1 are presented. These curves suggest that strains carrying the rad52 mutation may be more susceptible than wild type to X-ray-induced dominant lethal damage. For the crosses (+ × +, rad52 × rad52, + × rad52, rad52 × +) in which only one parent was irradiated, the relationships between zygote survival and X-ray dose were similar except for rad52 × rad52. In this cross a considerably higher frequency of dominant lethal damage was observed. This observation indicates that the rad52 mutant lacks a repair system for X-ray damage and is consistent with the proposal that unrepaired chromosome damage is the event which leads to dominant lethality and reproductive cell death.     

The effect of monostearoylglycerol on the metabolism of chylomicron-like lipid emulsions injected intravenously in rats

In rats, remnant particles derived from chylomicron-like emulsions containing 1,3-dioleoyl-2-stearoylglycerol (OSO) are removed from plasma more slowly than remnants derived from triolein emulsions. The effect associated with a saturated acyl chain at the glycerol 2-position could be reproduced by incorporating 2-stearoylglycerol (MS) in a triolein emulsion. When MS solubilized with rat albumin or in plasma was injected before the injection of a triolein emulsion, clearance of the triolein emulsion was unchanged. The metabolic fate of MS, monitored with 14C-labelled MS, was similar whether incorporated in triacylglycerol emulsion or injected independently. More than 95% of MS had disappeared from the circulation by 5 min after the injection and the radioactivity was found in liver, spleen, muscle and adipose tissue. Some MS label appeared in plasma triacylglycerol. Remnants made in vitro by incubating triolein or OSO emulsions with post-heparin plasma showed no differences in their disappearance from plasma. With OSO emulsion, the in vitro remnants were found to contain more MS than remnants made in vivo in hepatectomized rats. Simultaneous injections of mixtures containing OSO and triolein emulsions, or triolein emulsions with and without MS, each labelled with either [3H]cholesteryl oleate or [14C]cholesteryl oleate showed consistently slower remnant removal and decreased liver uptake of the emulsions containing OSO or MS. Affinity columns and immunodiffusion all indicated that there was no difference in the amounts of apolipoprotein E associated with OSO or triolein particles. The protein spectra of in vivo remnants derived from OSO and triolein emulsion were also similar when examined by SDS-PAGE and isoelectric focusing gels. Our results show that the effects due to OSO or MS are mediated by the presence of MS in the emulsion particle surface, while indirect effects expressed in plasma or liver are excluded. The precise mechanism of the effect remains to be established, but it does not correlate with measurable changes in the spectra of apolipoproteins associated with the emulsion remnants.     

Immunohistochemical identification of calcitonin gene-related peptide and substance P in nerves of the bovine parathyroid gland

Summary Although peptide neurotransmitters have been shown to modulate hormone secretion in many glands, there are very few studies of neurotransmitters in the parathyroid gland. Bovine parathyroid glands were collected at a local abattoir, fixed with paraformaldehyde, sectioned using a cryostat, and stained by indirect immunohistochemistry for calcitonin gene-related peptide and substance P. We were able to positively identify both neuropeptides. Nerve fibres containing calcitonin gene-related peptide and substance P were identified in contact with the tunica media of arteries and arterioles and dispersed throughout the stroma of the gland. While many of the fibres encircled parenchymal lobules, no intimate contact with the peripheral chief cells was observed. All immunoreactive fibres were found to contain both neuropeptides. Since calcitonin gene-related peptide and substance P are vasodilators, they may increase blood flow within the gland. In addition, the neuropeptides may diffuse from perilobular nerve fibres into the parenchyma, thereby modulating secretion of parathyroid hormone.     

Distribution of sperm counts in suspected infertile men

Probit plots of sperm concentration for 1711 suspected infertile men (those with azoospermia being excluded) were compared for the untransformed and loge-, square root- and cube root-transformed values. For the distribution of sperm concentrations, which was highly skewed towards low values, the square-root transformation produced the most normal (Gaussian) distribution. Loge and cube-root transformations caused skewing towards high values. Such treatment of the data should always be considered before using parametric statistical tests to make comparisons between sperm concentrations of groups of men.     

Serratia ficaria sp. nov., a bacterial species associated with Smyrna figs and the fig waspBlastophaga psenes

Fourteen strains isolated from figs, caprifigs, and fig wasps collected in California and Tunisia, and from a small black ant in France, constitute a new DNA hybridization group that is 25–56% related toSerratia species, and 6–17% related to other species of Enterobacteriaceae. This homogeneous group (90% relatedness within the group) constitutes a new species that is namedSerratia ficaria sp. nov. (type strain, ICPB 4050, ATCC 33105). Strains of this species have a characteristic odor, similar to that ofS: odorifera andPseudomonas perolens. No strain ofS. ficaria has yet been recovered from clinical specimens.     

The intracellular blue pigment of Pseudomonas lemonnieri

Summary The large-scale production, isolation, and purification are described of the blue insoluble intracellular pigment of the bacterium Pseudomonas lemonieri. The pigment, C₂₆H₃₇N₅O₆, occurs in the cells as a salt (cation unknown) of 6-octanoylamino-3-hydroxy-2-aza-benzoquinone-(1,4)-4-[5-octanoylamino-2,6-dihydroxy-pyridyl-(3)-imide] (I). Nitric acid oxidation of pigment I yields IV, 6-octanoylamino-3-hydroxy-2-aza-benzoquinone-(1,4). Further hydrolysis of IV splits off n-octanoic acid, which is free of homologues. The structures given for the pigment and its degradation products have been proven by identification with authentic preparations.Although they have different chromophores, the pigment (I) of Pseudomonas lemonnieri and N,N-dioctanoyl-indigoidine (VI) nevertheless resemble one another in IR-absorbances, NMR-spectra, and chromatographic behavior, because of homogeneous functional groups and ring structures. I and VI are indeed chemically related, as can be seen from the facts that aminocitrazinic acid is a common starting material for the in vitro syntheses of both compounds, and that the diazaindophenol (I) can be converted to the diaza-diphenoquinone (VI) by hydrogenation and subsequent autoxidation.Dedicated with devotion and admiration to Professor C. B. Van Niel on his seventieth birthday.     

The Two-Wavelength Method of Microspectrophotometry : III. An Extension Based on Photographic Color Transparencies

The two-wavelength method of microspectrophotometry corrects for distributional error and measures the amount of absorbing material by taking advantage of certain spectral characteristics of the specimen. Under certain circumstances, such as the absorption of nucleic acids in the ultraviolet and of black or multiple stains in the visible, the spectral characteristics are not suitable for the application of the method. To circumvent this, a photomicrograph of the object is taken with monochromatic light of a suitable wavelength. A second plate is exposed as a contact print of the photomicrograph and is developed in the presence of a coupling agent. After bleaching and fixation, the positive appears as a monochromatic color transparency. Two-wavelength analysis of such a transparency can be made in terms of the new color. The measurements will be free of distributional error and can be equated to the original object. The necessary formulae are derived, and a method which has proven suitable for color development is given. The photographic and the direct two-wavelength method were found to give equivalent results when both were used on the same series of liver nuclei. The application of the photographic method to ultraviolet absorption has been demonstrated. The new method is potentially applicable to other types of photographic densitometry involving heterogeneous images.     

Clonal morphogenesis of Lampropedia hyalina

Summary The characteristic arrangement of the cells of Lampropedia hyalina in rectangular sheets makes this bacterium an attractive model for studying clonal morphogenesis. In micro-slide cultures, clones develop from a single cell by growing and dividing along two parallel sets of growth axes, synchronized alternately by 90 degrees. The formation of the intracytoplasmic granules, chemically identified as poly--hydroxybutyric acid, also follows this pattern. One predominant granule occurs in each cell under standard cultural conditions (1.0% Difco yeast extract, 30°C), and formation of new polymer granules precedes division of the cell. The variation of environmental factors-such as pH in the presence of phosphate, nutrient concentration, and temperature-disturbs greatly the regular pattern of morphogenesis and cytogenesis in Lampropedia. This disarray includes an increase in the number of granules per cell; excessive amounts of polymer; distention and lysis of cells; disorderly arrangement of cells.Dedicated with affection and appreciation to Professor Dr. Richard Kuhn on his sixty-fifth birthday.