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The ability of soil microorganisms to solubilize phosphate is an important trait of plant growth-promoting bacteria leading to increased yields and smaller use of fertilizers. This study presents the isolation and characterization of phosphobacteria from Puna, northwestern Argentina and the ability to produce phosphate solubilization, alkaline phosphatase, siderophores, and indole acetic acid. The P-solubilizing activity was coincidental with a decrease in pH values of the tricalcium phosphate medium for all strains after 72 h of incubation. All the isolates showed the capacity to produce siderophores and indoles. Identification by 16S rDNA sequencing and phylogenetic analysis revealed that these strains belong to the genera Pantoea, Serratia, Enterobacter, and Pseudomonas. These isolates appear attractive for exploring their plant growth-promoting activity and potential field application. [ABSTRACT FROM AUTHOR]

Dipicolinic acid (pyridine-2,6-carboxylic acid; DPA) is a major component of bacterial spores and has been shown to be an important determinant of spore resistance. In the core of dormant Bacillus subtilis spores, DPA is associated with divalent calcium in a 1:1 chelate (Ca–DPA). Spores excrete Ca–DPA during germination, but it is unknown whether Ca and DPA are imported separately or together into the developing spore. Elemental analysis by scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDS) of wild-type spores and mutant spores lacking the ability to synthesize DPA showed that DPA-less spores also lacked calcium, suggesting that the two compounds may be co-imported. [ABSTRACT FROM AUTHOR]

Alanine racemase is a major component of the exosporium of Bacillus cereus spores. A gene homologous to that of alanine racemase ( alrA) was cloned from Bacillus thuringiensis subsp. kurstaki, and RT-PCR showed that alrA was transcribed only in the sporulating cells. Disruption of alrA did not affect the growth and sporulation of B. thuringiensis, but promoted l-alanine-induced spore germination. When the spore germination rate was measured by monitoring DPA release, complementation of the alrA disruptant reduced the rate of l-alanine-induced spore germination below that of even wild-type spores. As previously reported for spores of other Bacillus species, d-alanine was an effective and competitive inhibitor of l-alanine-induced germination of B. thuringiensis spores. d-cycloserine alone stimulated inosine-induced germination of B. thuringiensis spores in addition to increasing l-alanine-induced germination by inhibiting alanine racemase. d-Alanine also increased the rate of inosine-induced germination of wild-type spores. However, d-alanine inhibited inosine-induced germination of the alrA disruptant spores. It is possible that AlrA converted d-alanine to l-alanine, and this in turn, stimulated spore germination in B. thuringiensis. These results suggest that alrA plays a crucial role in moderating the germination rate of B. thuringiensis spores. [ABSTRACT FROM AUTHOR]

Talaromyces macrosporus forms ascospores that survive pasteurization treatments. Ascospores were dense (1.3 g ml–1), relatively dry [0.6 g H2O (g dry weight)–1] and packed with trehalose (9–17% fresh weight). Trehalose was degraded to glucose monomers between 30 and 100 min after heat activation of the spores. The maximal activity of trehalase was calculated as 400–520 nmol glucose formed min–1 (mg protein)–1 as judged by measurements of the trehalose content of spores during germination. During early germination, glucose was released from the cell (10% of the cell weight or more). The intracellular concentration of glucose only peaked briefly. After 160–200 min, the protoplast encompassed by the inner cell wall was ejected through the outer cell wall in a very quick process. Subsequently, respiration of spores increased strongly. The data suggested that trehalose is primarily present for the protection of cell components as glucose is released from the cell. Then, an impenetrable outer cell wall is shed before metabolic activity increases. [ABSTRACT FROM AUTHOR]

The UV-screening pigment scytonemin is found in many species of ensheathed cyanobacteria. Past work has shown that the pigment is synthesized in response to exposure to UV-A irradiance. This study investigated the effect of other correlated stress factors including heat, osmotic and oxidative stress on the synthesis of scytonemin in a clonal cyanobacterial isolate (Chroococcidiopsis sp.) from an epilithic desert crust. Stress experiments were carried out both in conjunction with UV-A irradiance and in isolation. Increases in both temperature and photooxidative conditions in conjunction with UV-A caused a synergistic increase in the rate of scytonemin production. In contrast, increased salt concentration under UV-A irradiance inhibited scytonemin synthesis. However, unlike the responses to temperature and oxidative stress, cells synthesized low levels of scytonemin under osmotic stress in the absence of scytonemin-inducing irradiance. These results suggest that scytonemin induction may be regulated as a part of a complex stress response pathway in which multiple environmental signals affect its synthesis. [ABSTRACT FROM AUTHOR]

Novel red, filamentous, gliding bacteria formed deep red layers in several alkaline hot springs in Yellowstone National Park. Filaments contained densely layered intracellular membranes and bacteriochlorophyll a. The in vivo absorption spectrum of the red layer filaments was distinct from other phototrophs, with unusual bacteriochlorophyll a signature peaks in the near-infrared (IR) region (807 nm and 911 nm). These absorption peaks were similar to the wavelengths penetrating to the red layer of the mats as measured with in situ spectroradiometry. The filaments also demonstrated maximal photosynthetic uptake of radiolabeled carbon sources at these wavelengths. The red layer filaments displayed anoxygenic photoheterotrophy, as evidenced by the specific incorporation of acetate, not bicarbonate, and by the absence of oxygen production. Photoheterotrophy was unaffected by sulfide and oxygen, but was diminished by high-intensity visible light. Near-IR radiation supported photoheterotrophy. Morphologically and spectrally similar filaments were observed in several springs in Yellowstone National Park, including Octopus Spring. Taken together, these data suggest that the red layer filaments are most similar to the photoheterotroph, Heliothrix oregonensis. Notable differences include mat position and coloration, absorption spectra, and prominent intracellular membranes. [ABSTRACT FROM AUTHOR]

In a spontaneous mutant (PYM1) of Bacillus cereus impaired in the synthesis of haem A, no haem-A-containing cytochromes were detected spectroscopically. The haem A deficiency was compensated by high levels of haem O and a CO-reactive cytochrome o in membranes; no other oxidases were detected. In contrast, the wild-type strain had considerable amounts of haem A and negligible levels of haem O. The mutant PYM1 exhibited normal colony morphology, growth, and sporulation in nonfermentable media, whereas on fermentable media, the mutant overproduced acid, which led to poor growth and inhibition of sporulation. External control of the pH of the medium in fermentable media allowed close-to-normal growth and massive sporulation of the mutant. The presence of membrane-bound cytochrome caa 3 -OII and aa 3 -II subunits in strain PYM1 was confirmed by Western blots and haem C staining (COII subunit). Western blotting also revealed that in contrast to the wild-type – strain PYM1 contained the membrane-bound subunits caa 3 -COI and aa 3 -I, but in low amounts. The effect of several respiratory inhibitors on the respiratory system of strain PYM1 suggested that the terminal oxidase is highly resistant to KCN and CO and that a c-type cytochrome might be involved in the electron transfer sequence to the putative cytochrome bo. [ABSTRACT FROM AUTHOR]

Tertiary butyl hydroperoxide (t-BOOH) was found to be sporicidal for Bacillus megaterium ATCC19213. Sporicidal action was very temperature dependent, and the potency of t-BOOH increased about tenfold for each increase in temperature of 15 °C over the range from 30° to 70 °C. At still higher temperatures, heat and μmolar levels of t-BOOH were mutually potentiating for killing. Vegetative cells and germinated spores were some thousand times less resistant to t-BOOH than dormant spores. The order of resistance for spores was: Bacillus stearothermophilus ATCC7953 > Bacillus subtilis var. niger = Bacillus megaterium ATCC33729 > Bacillus megaterium ATCC19213. Killing was not enhanced by decoating and occurred without germination or loss of refractility of the spores. Spore resistance to t-BOOH was lower at more acid pH values and was decreased also by demineralization. Spores could be protected by the chelator o-phenanthroline, especially in association with Fe. Overall, it seemed that killing was associated with nonmetabolic formation of alkyl peroxyl radicals, which are thought to be responsible for killing of vegetative cells by organic hydroperoxides. [ABSTRACT FROM AUTHOR]

A recently described new method for determination of killer toxin activity was used for kinetic measurenments of K1 toxin binding. The cells of the killer sensitive strain Saccharomyces cerevisiae S6 were shown to carry two classes of toxin binding sites differing widely in their half-saturation constants and maximum binding rates. The low-affinity and high-velocity binding component ( K=2.6x10 L.U./ml, V=0.19 s) probably reflects diffusion-limited binding to cell wall receptors; the high-affinity and low-velocity component ( K=3.2x10 L.U./ml, V=0.03 s) presumably indicates the binding of the toxin to plasma membrane receptors. Adsorption of most of the killer toxin K1 to the surface of sensitive cells occured within 1 min and was virtually complete within 5 min. The amount of toxin that saturated practically all cell receptors was about 600 lethal units (L.U.) per cell of S. cerevisiae S6. [ABSTRACT FROM AUTHOR]

A homothallic haploid strain of the fission yeast Schizosaccharomyces pombe initiates sexual reproduction (mating, meiosis and sporulation) in nitrogen-free sporulation medium. Cellular fine structures of eleven sporulation-deficient mutants ( spo2, spo3, spo4, spo5, spo6, spo13, spo14, spo15, spo18, spo19 and spo20) of S. pombe in sporulation medium were examined by serial section-electron microscopy. The striking features of these spo mutants were: 1) the disappearance of the spindle pole bodies (SPBs) after the second meiotic division, and 2) the accumulation of unorganized structures. Based on histochemical staining, these structures were presumably unorganized spore wall precursors. In some mutants ( spo3, spo5, spo6, spo19 and spo20), diploid zygotes contained four spore-like bodies which had walls similar to complete spore walls but failed to enclose any nuclei. After completion of the second meiotic division the nuclei were abnormally distributed in zygotic diploid cells. In the spo5, spo13, spo14, spo15 and spo19 mutants, the nuclei remained attached to each other. In spo5 and spo19, the inner membrane of the nuclear envelope was separated, but its outer membrane was shared by two sister nuclei. These observations suggest that the spo gene products play important roles in spatial and temporal organization of cellular structures during ascospore development. [ABSTRACT FROM AUTHOR]

The response of Acinetobacter strain 210A to low phosphate concentrations was investigated in P- or C-limited chemostat cultures. The organism accumulated poly-β-hydroxybutyric acid under P-deprivation, at phosphate concentrations ranging from 0.1 to 0.7 mM. The amount of biomass was proportional to the phosphate concentration in the medium and no polyphosphate was formed. When shifting a culture from P- to C-limitation phosphate was accumulated as polyphosphate. No poly-β-hydroxybutyrate could be detected in these cells. The amount of polyphosphate in the cell showed a hysteresis. When cultures were shifted from low to high phosphate concentrations, polyphosphate reached a maximum of about 60 mg P per gram of dry weight at about 3 times excess phosphate (ca. 2.5 mM P). It decreased to 45 mg P per gram dry weight at approximately 5 times the phosphate needed for growth (ca. 3.5 mM P). In the reverse case (high to low) polyphosphate did never exceed 45 mg P per gram dry weight. The specific activities of alkaline phosphatase and the phosphate uptake system were induced at residual P concentrations below the detection limit (<10 μM). The specific uptake rate followed also a hysteresis. The specific activities of polyphosphatase and polyphosphate: AMP phosphotransferase increased when polyphosphate formation was possible. [ABSTRACT FROM AUTHOR]

Spirochetes were found in the lower anoxiphototrophic layer of a stratified microbial mat (North Pond, Laguna Figueroa, Baja California, Mexico). Ultrastructural analysis of thin sections of field samples revealed spirochetes approximately 0.25 μm in diameter with 10 or more periplasmic flagella, leading to the interpretation that these spirochetes bear 10 flagellar insertions on each end. Morphometric study showed these free-living spirochetes greatly resemble certain symbiotic ones, i.e., Borrelia and certain termite spirochetes, the transverse sections of which are presented here. The ultrastructure of this spirochete also resembles Hollandina and Diplocalyx (spirochetes symbiotic in arthropods) more than it does Spirochaeta, the well known genus of mud-dwelling spirochetes. The new spirochete was detected in mat material cellected both in 1985 and in 1987. Unique morphology (i.e., conspicuous outer coat of inner membrane, large number of periplasmic flagella) and ecology prompt us to name a new free-living spirochete. [ABSTRACT FROM AUTHOR]

A calcium requirement was shown for both vesicle development and nitrogenase activity by Frankia strains EAN1 and CpI1. Washing cells with EGTA or EDTA inhibited both vesicle development and nitrogenase activity. The inhibition of both was reversed by the addition of calcium. A variety of agents known to affect calcium-dependent biological processes, such as a Ca-ATPase inhibitor, Ca-channel blockers, Ca-ionophores, calmodulin antagonists and the local anaesthetics, tetracaine and dibucaine, inhibited nitrogenase activity. Respiratory studies showed that a CN-insensitive respiration process occurred only under nitrogen derepressing conditions. Respiration by NHCl-grown cells was completely inhibited by KCN while N-grown cells were inhibited by only 70%. Removal of calcium ions by EGTA or by the addition of dibucaine or tetracaine blocked the CN-insensitive respiration. This CN-insensitive respiration may be involved in protecting nitrogenase inside the vesicles from oxygen. [ABSTRACT FROM AUTHOR]

An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8-0.9 μm wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300-1200 μm, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur bacteria is not available yet in pure culture, and its taxonomical position cannot be fully established. This organism is suggested to be a new type of gliding, filamentous, purple phototroph. [ABSTRACT FROM AUTHOR]

The effect of estradiol, hydrocortisone and progesterone on 3α,20β-and 3β,17β-hydroxysteroid dehydrogenase (HSD) in mutants of Streptomyces hydrogenans was compared to the steroid response of the wild type. Mutants were defective in arginine biosynthesis and/or aerial mycelial formation and lacked both enzymes or only 17β-HSD. Some 17β-HSD mutants had lost the ability to be induced by estradiol, by progesterone or by both. Some 20β-HSD mutants had lost the ability to be induced by hydrocortisone, by progesterone or by both. Non-inducibility of 17β-and 20β-HSD by progesterone was not co-ordinate. An additional study of the growth phase-dependent enzyme activity of the wild type after induction with estradiol, hydrocortisone and progesterone was performed. [ABSTRACT FROM AUTHOR]

In order to determine the phylogenetic relationships of representatives of three Gram-negative genera, Sporomusa, Selenomonas, and Megasphaera, the 16S ribosomal RNAs were compared by oligonucleotide cataloguing. Surprisingly, Sporomusa ovata, S. sphaeroides, Selenomonas ruminantium, and Megasphaera elsdenii do not group with any of the 200 Gram-negative eubacterial species investigated so far by this method but show a distinct although remote relationship to Gram-positive eubacteria of the ' Clostridium subdivision'. The presence of Gram-negative species within the radiation of the cluster defined by Gram-positive cubacteria reduces the significance the Gram-positive staining behaviour plays in taxonomic and phylogenetic studies. It furthermore supports previous findings showing the Gram-negative and phototrophic species Heliobacterium chlorum to be a member of the Clostridium-Bacillus cluster. The presence of Gram-negative endospore-containing Sporomusa species among the 16S rRNA cluster of Gram-positive endospore-forming eubacteria allow speculations about the evolutionary origin of Gram-positive eubacteria. [ABSTRACT FROM AUTHOR]

Accumulation of poly-β-hydroxybutyrate (PHB) was studied in Alcaligenes eutrophus strain N9A. Under nitrogen limitation and heterotrophic conditions, the cells accumulated PHB at a rate of 50 fg cell h. Volume increased from 1.208 to 3.808 μm and buoyant density from 1.110 to 1.145 pg μm with an increase in PHB from 0 up to 1.699 pg cell. Volume was found to change linearly with PHB content. The changes were due to increases in cell width and not in cell length. PHB explained 93% of the changes in cellular volume. The relationship between density and PHB was hyperbolic. PHB explained 96% of the changes in density. When a mutant strain unable to accumulate PHB was analyzed together with the wild type, the PHB-less mutant and the wild type showed densities of 1.100 pg μm and 1.120 pg μm, respectively, in gradients of 65% Percoll. In sucrose gradients, nevertheless, the results were reversed. This discrepancy was explained by the high osmolarity of sucrose which gives artificial results. Thus, we conclude that Percoll is a more suitable medium than sucrose to measure the density of live bacterial cells. [ABSTRACT FROM AUTHOR]

An unusual filamentous, gliding bacterium was found in a few hot springs in Oregon where it formed a nearly unispecific top layer of microbial mats. It contained a bacteriochlorophyll a-like pigment and an abundance of carotenoids. There were no chlorosomes or additional chlorophylls. The organism was aerotolerant and appeared to be photoheterotrophic. It was successfully co-cultured with an aerobic chemoheterotroph in a medium containing glucose and casamino acids. Although it has many characteristics in common with the genus Chloroflexus, the lack of chlorosomes and bacteriochlorophyll c and the aerobic nature of this organism indicate that it should be placed in a new genus. This conclusion is supported by 5S rRNA nucleotide sequence data. [ABSTRACT FROM AUTHOR]

The subcellular localization of the enzyme invertase in Schizosaccharomyces pombe cells, both repressed and derepressed for synthesis of the enzyme, was studied. Most of the invertase was found to be located outside the plasma membrane and only a small percentage was found to be associated to membranes. A substantial portion of the external enzyme remained firmly bound to cell-wall material. All of the invertase recovered in soluble form from cellular extracts reacted with concanavalin A and with the lectin from Bandeiraea simplicifolia seeds, indicating the presence in the enzyme of a carbohydrate moiety which probably contains terminal mannosyl (or structurally related) and galactosyl residues. The possibility of the presence of two different forms of invertase in S. pombe was considered. An intracellular, soluble form of invertase, devoid of carbohydrate, similar to the small invertase of the budding yeast Saccharomyces cerevisiae, was not found in S. pombe. However, the Michaelis constant for sucrose of the enzyme present in repressed cells was smaller than that of the invertase synthesized under derepressing conditions, although this difference could also be the result of a different pattern of glycosylation of the invertase synthesized under different growth conditions. [ABSTRACT FROM AUTHOR]

Leucine dehydrogenase ( l-leucine: NAD oxidoreductase, deaminating, EC 1.4.1.9) has been purified to homogeneity from a moderate thermophilic bacterium, Bacillus stearothermophilus. Am improved method of preparative slab gel electrophoresis was used effectively to purify it. The enzyme has a molecular mass of about 300,000 and consists of six subunits with identical molecular mass (Mr, 49,000). The enzyme does not lose its activity by heat treatment at 70° C for 20 min, and incubation in the pH range of 5.5-10.0 at 55° C for 5 min. It is stable in 10 mM phosphate buffer (pH 7.2) containing 0.01% 2-mercaptoethanol at over 1 month, and is resistant to detergent and ethanol treatment. The enzyme catalyzes the oxidative deamination of branched-chain l-amino acids and the reductive amination of their keto analogs in the presence of NAD and NADH, respectively, as the coenzymes. The pH optima are 11 for the deamination of l-leucine, and 9.7 and 8.8 for the amination of α-ketoisocaproate and α-ketoisovalerate, respectively. The Michaelis constants were determined: 4.4 mM for l-leucine, 3.3 mM for l-valine, 1.4 mM for l-isoleucine and 0.49 mM for NAD in the oxidative deamination. The B. stearothermophilus enzyme shows similar catalytic properties, but higher activities than that from Bacillus sphaericus. [ABSTRACT FROM AUTHOR]

Sporosarcina halophila forms endospores. Electron micrographs revealed ultrastructural similarity to spores of S. ureae. Spore germination indicated by loss of refractility, darkening, swelling and formation of new vegetative cells was followed by phase contrast light microscopy. To induce spore germination, the endospores needed to be heat avtivated. After activation, they were inoculated into nutrient broth medium supplemented with sea-water. Double concentrated sea-water was found to be optimal for germination. Similar to other bacterial endospores, the spores were found to be resistant to heat and ethanol. An ultraviolet absorbing substance was isolated from suspensions of free spores; it was identified to be pyridine-2,6-dicarboxylic acid (DPA) usually present in bacterial spores. DPA was detected in amounts ranging from 5-7% of the spore dry weight; it was not detected in extracts of vegetative cells. [ABSTRACT FROM AUTHOR]

Lipid classes and fatty acid distribution were analysed in the resting sporangium of Synchytrium endobioticum, the causal agent of the potato wart disease. The sporangium contents were shown to have lipid droplets, the major fatty acids there being C, C, and C. The sporangium wall on the other hand was composed of C, C, C, C, and C fatty acids. A significantly large portion of the sporangium wall lipids contained wax esters with branched chains. [ABSTRACT FROM AUTHOR]

Oscillatoria amphigranulata is a fast-growing (3 doublings/day) cyanobacterium isolated from sulfide hot springs in New Zealand. Photosynthesis, as measured by incorporation of [C]-HCO, was initially inhibited by 0.3-1.5 mM sulfide at pH 7.9-8.1. However, conversion to sulfide-dependent anoxygenic photosynthesis occurred in about 2 h or less under light intensities of 3-14 klx. Under the stimulation of higher light intensity (8-14 klx) a partial recovery of oxygenic photosynthesis also occurred. It was concluded that oxygenic photosynthesis was responsible for 21-42% of the total incorporation at sulfide concentrations of 1.0-0.3 mM, respectively. This contribution was suppressed at 1.5 mM sulfide and not elicited under lower light intensities (3-7 klx). As judged by the inhibitory effect of 10 μg/ml chloramphenicol protein synthesis was required for attainment of both anoxygenic photosynthesis and photosystem II recovery. Sulfide could not be replaced by thiosulfate, elemental sulfur or dithionite as electron donors in photosynthesis, but elemental sulfur could serve as the sole assimilatory source of sulfur. Oxygenic photosynthesis was inhibited by DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea] or DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), but sulfide relieved the effect of either inhibitor in adapted cells, indicating that electrons derived from sulfide enter the photosynthetic electron transport chain at a point beyond plastoquinone. [ABSTRACT FROM AUTHOR]

A flexing and gliding green sulfur bacterium has been isolated from marine sources off the North East coast of the USA. Chloroherpeton thalassium is an obligate phototroph, and requires CO and S for growth; some organic acids can contribute to cell carbon, and N may be fixed. The cells contain typical chlorosomes, and gas vesicles may be present. Bacteriochlorophyll c is the main light harvesting pigment, and a small quantity of bacteriochlorophyll a is also present. Over 80% of the carotenoid is γ-carotene. DNA base composition of the isolates ranges from 45.0-48.2 mol% G+C. [ABSTRACT FROM AUTHOR]

The intraspecific fusion frequencies obtained with the direct selection method on a semi-synthetic regeneration medium between strains of B. subtilis and B. licheniformis were distribution from 9.9×10 to 4.5×10, which was one or two orders higher than those of interspecific recombinations between B. subtilis and B. licheniformis. The regeneration media were also useful for selecting interspecific transformants from plasmid carrier to non-carrier. This selection could be used as a primary selection method for inter-and intraspecific recombinants obtained by protoplast fusion. [ABSTRACT FROM AUTHOR]

Invertase (β- d-fructofuranosidase, EC 3.2.1.26) activity appeared in cultures and mycelial suspensions of a thermophilic fungus. Thermomyces lanuginosus, only when sucrose or raffinose was added as the carbon source to the medium. The enzyme activity disappeared rapidly following the exhaustion of sugar in the culture medium. Extracellular invertase activity was not detected. The maximal enzyme activity occurred prior to the maximal growth of the fungus. The appearance of invertase activity was dependent on growth. The enzyme activity was not stable in cell-free extracts of mycelia. The lability of the enzyme was also observed in mycelia incubated in the presence of cycloheximide. In the above respects the behaviour of invertase in T. lanuginosus differs from invertase of yeasts and molds (mesophiles) which have been studied. [ABSTRACT FROM AUTHOR]

Previous work has shown that high molecular weight compounds were released from Saccharomyces bisporus by β-mercaptoethanol, 2 M KCl, 0.5 M KCl and osmotic shock without affecting viability of the cells. In this current experiment, it was shown that low molecular weight compounds were also eluted when cells were treated in sequence with the same reagents. Alanine, glutamate, serine, an unidentified amino acid, glucose, glycerol, and arabitol were all eluted by each of the first three reagents. The osmotic shock eluate contained a larger number and quantity of amino acids than the first three eluates but, otherwise, the compounds in this eluate were the same. One hundred percent of the cellular glycerol and 65-70% of the total amounts of the other above mentioned solutes were released by the 4 eluting treatments. A hot water treatment was needed to extract the remainder of these solutes. The hot water extract also contained almost all the cellular proline. It was suggested that the elutable solutes are contained by cells in compartments (or vesicles) whose membranes are accessible to the eluting reagents without affecting the plasmalemma. [ABSTRACT FROM AUTHOR]

When diploid cells of Saccharomyces cerevisiae were incubated in acetate growth media containing 2.5 mM ethyl N-phenylcarbamate (EPC), bud initiation was inhibited preferentially, and eventually overgrown, unbudded cells accumulated. During subsequent incubation, meiosis and ascospore formation occurred at high frequencies. The behavior of EPC-treated cells was essentially the same as that of cells transferred to a starvation sporulation medium. EPC thus has a pronounced effect on the mitotic growth of yeast cells, which leads to meiotic development. Our observations indicate that EPC has a decisive function in the initiation of meiosis in rich growth media. [ABSTRACT FROM AUTHOR]

The properties of endospores of some thermophilic strains of Bacillus were examined. Included were strains isolated from thermal pools and springs in Yellowstone National Park, a strain of B. thermodenitrificans and two strains of B. stearothermophilus, ATCC 7953 (smooth) and T-10. The spores of thermophilic strains of Bacillus contained relatively high levels of dipicolinic acid ranging from 11-14.8% of the spore dry weight, while the calcium levels were similar to those observed in other bacterial endospores including mesophilic bacilli and thermophilic actinonycetes. Spore populations of thermophilic bacilli could not be effectively germinated in solutions of sodium phosphate alone but germinated well in solutions supplemented with one of a variety of organic compounds. Solutions containing l-valine or l-leucine were particularly effective. A wide range of pH permitted the germination of fractions of spore populations, however, optimum germination was observed only at pH values of 6.0 and above. A range in incubation temperatures of less than 25°C permitted 50% or more of the spores of each of the organisms to germinate. Freshly prepared spores did not germinate, but these spores germinated rapidly and completely if they were heated for 30 min at 100°C just prior to germination testing, i.e., the spores were heat activatable. However, spores of thermophilic bacilli could also be activated by shifting them to and holding them at temperatures below their optimum growth temperature of 65°C. Of the ten temperatures tested, ranging from 4°C through 50°C, the optimum reduced temperature for spore activation was 30°C. [ABSTRACT FROM AUTHOR]

Bacillus brevis strain Nagano and its gramicidin S-negative mutant, BI-7, were compared with respect to germination of their spores produced in several media. Germination initiation occurred in the presence of nutrient broth or L-alanine but not with inosine, glucose, glycerol or fructose; the process was activated by heat. Parental and mutant spores behaved similarly in these experiments. During outgrowth, parental spores remained in this phase of germination much longer than did mutant spores, but only when the parental spores had been harvested from a sporulation medium where significant gramicidin S synthesis had occurred. When parental spores were extracted or treated with an enzyme that hydrolyzes gramicidin S, rapid outgrowth occurred. Adding exogenous gramicidin S or the extract from parental spores to mutant spores lengthened the outgrowth in a dose-dependent manner. The uptake of labeled L-alanine by parental spores was delayed compared to mutant spores in the presence or absence of chloramphenicol. These data suggest a mechanism of action for gramicidin S whereby it interferes in membrane function, such as transport or energy metabolism, in outgrowing spores. [ABSTRACT FROM AUTHOR]

The tubulin proteins of Blastocladiella emersonii have been characterized, and the pool sizes of soluble tubulins measured to evaluate turnover during early development. The axonemal tubulins and soluble tubulin dimers were typical of tubulin proteins from other eukaryotes. [H]cholchicine binding assays were used to estimate the soluble tubulin pools of zoospores and during early development. The free colchicine-binding pool of tubulin in zoospores represents 1% of the soluble protein. It increases by 49% after encystment (at 30 min), decreases to 21% below the spore level by 50 min, and then increases slowly with growth. Neither deflagellation of zoospores prior to encystment, nor inhibition of axonemal disassembly, alter the postencystment pool increases. Disassembly of cytoskeletal microtubules occurs in either circumstance, but can account for only 54% of the pool increase. It was concluded that (1) the retracted axonemal tubulins are not returned to the soluble pool detected by cholchicine binding and are probably degraded; (2) new microtubules are supplied by the preexisting cytoplasmic pool that expands from disassembly of cytoplasmic microtubules; and (3) that the tubulins of the axonemes and soluble pools may be distinct. [ABSTRACT FROM AUTHOR]

Cell free extracts prepared from exponentially growing Escherichia coli and Bacillus cereus as well as from Bacillus cereus at the end of exponential growth were optimized for various factors required for amino acid incorporation when programmed with Bacillus ribonucleic acid. All three preparations synthesized glutamine synthetase antigen when ribonucleic acid from a Bacillus subtilis strain that overproduces glutamine synthetase was added. The post exponential Bacillus cereus extract, however, was most active for the synthesis of Bacillus cereus spore coat antigen when supplemented with the appropriate ribonucleic acid. There appears to be some specificity in the translation of at least this sporulation messenger RNA. [ABSTRACT FROM AUTHOR]