Poly-beta-Hydroxybutyrate Accumulation as a Measure of Unbalanced Growth of the Estuarine Detrital Microbiota

The procaryotic endogenous storage material poly-beta-hydroxybutyrate (PHB) can be induced to accumulate in the estuarine detrital microbiota under conditions which suggest unbalanced growth, such as limitation of a critical factor(s) in the presence of carbon and energy sources. Changes in PHB-to-lipid phosphate ratios detected in field samples can be mimicked in the laboratory with common estuarine stresses. Acute anoxia or low pH induces conditions of no growth with depression of both the synthesis and catabolism of PHB without change in the lipid phosphate. Balanced growth induced by nutrients increases the lipid phosphate, depresses PHB synthesis, and stimulates PHB catabolism, resulting in a low ratio of PHB to lipid phosphate. Unbalanced growth induced to a small extent by high salinity or much more readily by dark upland runoff water results in rapid accumulation of PHB and slowing of PHB catabolism with little change in lipid phospate. Unbalanced growth conditions result in high PHB-to-lipid phosphate ratios in the detrital microbiota.     

Rapid Recovery of Escherichia coli from Estuarine Water

The efficiencies of two 24-hr elevated-temperature tests to recover Escherichia coli from estaurine water were compared simultaneously with the 72-hr standard methods procedure of the American Public Health Association (APHA). From 1,710 tubes, E. coli was recovered 222 times in lauryl tryptose medium incubated at 44 ± 0.2 C for 24 hr, 261 times in an experimental medium incubated at 44.5 ± 0.2 C for 24 hr, and 257 times by the 72-hr APHA method. The number of false positives enumerated was similar in all three tests. The data indicated that E. coli in raw seawater could be determined in 24 hr without a significant loss of accuracy.     

Estuarine habitats protect hybrid mussels from selection

The marine mussels, Mytilus edulis and Mytilus galloprovincialis, form an extensive hybrid zone in Europe where F₂ hybrids and mussels of mixed genetic ancestry are often locally abundant. Hybrid zones are maintained by the interplay of dispersal and selection on hybrid genotypes but there has been vigorous debate on the form of selection that may occur in these systems. Tension zone models argue that selection is against hybrids because of developmental misregulation and is independent of the external environment. Exogenous selection models argue that selection is habitat-dependent and the structure of the hybrid zone is due to the distribution of habitat patches that vary in selection intensity. We test this prediction by comparing the genetic structure of mussel populations in open-coast habitats, where selection on hybrids is strong, to those within two independent estuaries. We show that mussels within these estuaries are protected from selection and thus selection is strongly dependent on habitat, which supports the exogenous selection hypothesis. Hybrid mussel populations on the open-coast experience strong selection against M. edulis-like genotypes, which has been postulated to be the result of differential dislodgment by waves. This hypothesis is supported by our results since mussels within sheltered habitats are protected from selection. There was, despite previous suggestions, no evidence of selection in favor of M. edulis-like mussels within either estuary.     

Hyperproduction of Poly-beta-Hydroxybutyrate during Exponential Growth of Azotobacter vinelandii UWD

The transformation of Azotobacter vinelandii UW with A. vinelandii 113 DNA resulted in the formation of rifampin-resistant colonies, 13% of which also inherited a previously unrecognized mutation in the respiratory NADH oxidase. These transformants produced colonies with a white-sectored phenotype after prolonged incubation. Cells from these sectors were separated and purified by streaking and were named UWD. The dense white phenotype was due to the production of a large amount of poly-beta-hydroxybutyrate during the exponential growth of strain UWD. The polymer accounted for 65 or 75% of the cell dry weight after 24 h of incubation of cultures containing glucose and either ammonium acetate or N(2), respectively, as the nitrogen source. Under the same conditions, strain UW cells contained 22 to 25% poly-beta-hydroxybutyrate, but O(2)-limited growth was required for these optimal production values. Polymer production was not dependent on O(2) limitation in strain UWD, but the efficiency of conversion of glucose to poly-beta-hydroxybutyrate was enhanced in O(2)-limited cultures. Conversion efficiencies were >0.25 and 0.33 mg of poly-beta-hydroxybutyrate per mg of glucose consumed under vigorous- and low-aeration conditions, respectively, compared with an efficiency of 0.05 achieved by strain UW. Strain UWD, therefore, appeared to from poly-beta-hydroxybutyrate under novel conditions, which may be useful in designing new methods for the industrial production of biodegradable plastics.     

Purification of Poly-beta-Hydroxybutyrate by Density Gradient Centrifugation in Sodium Bromide

Fractionation of fully sporulated cultures of Bacillus thuringiensis by density gradient centrifugation in NaBr produced two bands which were identified as poly-beta-hydroxybutyrate. This technique generated high yields of membrane-bound and unbound granules of exceptional purity and degree of polymerization.     

Microflora of Drainage from Ice in Fishing Vessel Fishholds

The microbial load in ice-melt drainage collected from fishholds of fishing vessels stowing lizard fish, black croakers, cuttle fish, or nemipterids was very high, ranging from 2.1 × 10⁷ to 2.2 × 10⁹/ml for bacteria and 6.3 × 10³ to 7.2 × 10⁴/ml for yeasts and molds. Analysis of 100 colonies each randomly isolated from drainage samples of cuttle fish and lizard fish showed that the occurrence of bacterial genera as a percentage of the total was Moraxella-Acinetobacter, 61 to 62%; Pseudomonas, 19 to 21%; Alcaligens, 5 to 10%; Flavobacterium, 1 to 4%; Micrococcus, 1 to 4%; Bacillus, Vibrio 0 to 2%; Corynebacterium, 1 to 2%; and others, 1 to 2%. The organisms demonstrated versatile hydrolytic activities to a wide range of biological substrates including casein, gelatin, starch, DNA, and RNA. The possible connection between these bacteria and the deterioration of fish quality are discussed.     

Determination of Poly-beta-Hydroxybutyrate and Poly-beta-Hydroxyvalerate in Activated Sludge by Gas-Liquid Chromatography

A convenient gas-liquid chromatography procedure to quantify poly-beta-hydroxybutyrate and poly-beta-hydroxyvalerate in activated sludge was developed by combining lyophilization of the samples, purification of the chloroform phase by water reextraction, and the use of capillary columns. With a flame ionization detector the sensitivity was estimated at 10 g/liter.     

Enzymes of the Poly-beta-Hydroxybutyrate and Citric Acid Cycles of Rhizobium japonicum Bacteroids

The activities of several enzymes of the citric acid and poly-β-hydroxybutyrate cycles were measured in Rhizobium japonicum 3I1B-143 bacteroids which had been isolated from soybean nodules by sucrose gradient centrifugation. During the period of developing nitrogenase activity, the specific activity of fumarase, hydroxybutyrate dehydrogenase, β-ketothiolase, and pyruvate dehydrogenase complex increased whereas acetoacetate-succinyl-CoA transferase and isocitrate dehydrogenase decreased. Malate dehydrogenase activity remained constant. The amount of available acetyl-CoA, based on pyruvate dehydrogenase activity, should be sufficient to support both metabolic cycles concurrently. The temporal relationship between nitrogenase activity and poly-β-hydroxybutyrate accumulation has been reexamined.     

Molecular Analysis of Malassezia Microflora from Patients with Pityriasis Versicolor

Background: Pityriasis versicolor (PV) is a superficial infection of the stratum corneum caused by Malassezia species. Eleven species have been identified within this genus, namely M. globosa, M. restricta, M. sympodialis, M. furfur, M. obtusa, M. slooffiae, M. pachydermatis, M. dermatis, M. japonica, M. yamatoensis, M. nana. M. furfur has long been identified as the causative fungus of PV. However, recent studies using the culture and isolation identified by morphological and physiological characteristics suggest that M. globosa is the causative agent of PV. Objectives: The aim of this study was to examine the distribution of PV microorganisms with a molecular-based non-culture method. Patients: The subjects were 49 patients with PV (32 males, 17 females; 16–83 years old) who visited our outpatient clinic. Methods: Samples were taken from lesions for direct microscopy with methylene blue and detected Malassezia species without M. pachydermatis and M. nana using a non-culture-based method consisting of nested PCR with specific primers. Results: The most frequently isolated species were M. globosa and M. restricta (both 93.9%). Only M. globosa was detected from the lesion in which the mycelial form alone was observed microscopically, but M. restricta was not. Conclusions: Our results suggest that M. globosa is the causative agent of PV.     

Microflora of banh men,a fermentation starter from Vietnam

In this study Banh mensamples obtained from Vietnam were analysed in terms of pH, moisture content and fungal composition. The banh men pH proved to be acidic with a mean pH of 5.76. Moisture content was 13.6%. Total mould and yeast counts yielded 1.3 × 10⁶ and 4.3 × 10⁶ c.f.u./g-fresh sample, respectively. A total of 53 fungal isolates were obtained from 20 moulds and 33 yeasts. The mould isolates were identified as Rhizopus oryzae, Mucor indicus, Mucor circinilloides, and Amylomyces rouxii. The yeast isolates were identified as Saccharomyces cerevisiae, Hyphopichia burtonii, Saccharomycopsis fibuligera, Pichia anomala, and Candida sp. Based on the parameters used in this study, it can be deduced that banh men is similar to ragi and other Asian fermentation starters.     

Microflora of Barley Kernels

Numbers and kinds of microflora were determined in 160 samples of barley grown in different regions of the United States; microflora were more abundant in the grains grown in the central states than in those grown in the western states. During steeping and germination in micromalting equipment, the number of colonies of filamentous fungi increased from two to five times, colonies of yeasts from five to ten times, and bacteria from 50 to more than 100 times the numbers present in the grain before malting. Kiln drying according to a commercial schedule reduced the number of all types of microflora below the number present before kilning, but all were present in larger numbers in the kilned malt than in the original grain. In barley stored at room temperature and at a moisture content of 15 to 18%, members of the Aspergillus glaucus group increased with increasing time and increasing moisture content, and germination percentage of the seeds decreased. Stored free of storage fungi at room temperature, barley with a moisture content just over 15% retained a high germination percentage for 5 months, but at a moisture content of 16% the germination decreased to zero.     

Microbial Iron Reduction by Enrichment Cultures Isolated from Estuarine Sediments

Microbial Fe reduction in acetate- and succinate-containing enrichment cultures initiated with an estuarine sediment inoculum was studied. Fe reduction was unaffected when SO₄²⁻ reduction was inhibited by MoO₄²⁻, indicating that both processes could occur independently. Bacterially produced sulfide precipitated as FeS but was not completely responsible for Fe reduction. The separation of oxidized Fe particles from bacteria by dialysis tubing demonstrated that direct bacterial contact was necessary for Fe reduction. Fe reduction in cultures amended with NO₃⁻ was delayed until NO₃⁻ and NO₂⁻ were removed. However, bacterial attachment to oxidized Fe particles in NO₃⁻-amended cultures occurred early during growth in a manner similar to NO₃⁻-free cultures. During late stages of growth, bacteria not attached to Fe particles became pale and swollen, while attached cells remained bright blue when examined by 4′,6-diamidine-2-phenylindole epifluo-rescence microscopy. The presence of added oxidized Mn had no effect on Fe reduction. The results suggested that enzymatic Fe reduction was responsible for reducing Fe in these cultures even in the presence of sulfide and that cells incapable of Fe reduction became unhealthy when Fe(III) was the only available electron acceptor.