Anisaldehyde production and aryl-alcohol oxidase and dehydrogenase activities in ligninolytic fungi of the genus Pleurotus.

A variety of simple aromatic compounds were identified in liquid cultures of the basidiomycetes Pleurotus cornucopiae, P. eryngii, P. floridanus, P. pulmonarius, P. ostreatus, and P. sajor-caju by using gas chromatography-mass spectrometry. Such compounds were detected in fungal cultures on lignin- and straw-containing media, but it was found that they were also produced in the absence of aromatic precursors. Anisylic and hydroxybenzylic compounds (such as alcohols, aldehydes, and acids) were identified, p-anisaldehyde being the most characteristic extracellular metabolite synthesized by these ligninolytic fungi. Small amounts of 3-chloro-p-anisaldehyde were also detected in several species. It is postulated that the balance between the more-or-less-oxidized aromatic compounds can be explained in terms of the activity of fungal enzymes, including aryl-alcohol oxidase and dehydrogenase. The former enzyme shows high affinity for p-anisyl alcohol, which is oxidized to p-anisaldehyde with production of H2O2. The aryl-alcohol dehydrogenase was detected only in the mycelium, where it reduces aromatic aldehydes in the presence of NADPH. Both enzymes could be involved in the redox cycling of these aromatic compounds, providing H2O2 to ligninolytic peroxidases.     

The influence of pH on growth kinetics of yeasts in the presence of benzoate as a sole carbon source

The inhibitory effect and substrate properties of benzoic acid were estimated for 25 yeast strains belonging to generaCondida, Hansenula, Hypopichia, Rhodosporidium, Rhodotorula, Saitoella andTrichosporon. Benzoic acid can serve as a sole carbon source for growth of yeasts belong to generaRhodotorula, Rhodosporidium andSaitoella in synthetic mineral media. Specific growth rate is strongly dependent both on the concentration of benzoate and the pH value of the cultivation media. Maximum specific growth rate on benzoate is observed in alkaline cultivation media at pH 7.0–7.5 whereas those for growth on glucose in mildly acidic media at pH 5.0. Some of the strains showed weak growth on benzoate even at pH 8.5. Some carotenoid-containing yeasts of the generaRhodotorula andRhodosporidium lost their ability to synthesize carotenoid pigments during growth in alkaline benzoate media.     

A new phage typing scheme forProteus mirabilis andProteus vulgaris strains

A new bacteriophage typing set, composed of 22 phages, was established as a tool for differentiation ofProteus strains. All the phages were tailed and included 4 morphological types (A1, A2, B1 and C1). They were classified into the familiesMyoviridae, Siphoviridae andPodoviridae. From the set, 19 phages had double-stranded DNA and 3 were single-stranded DNA phages.     

Inhibitory effect of lignin by-products of pulping on yeast growth

The antimicrobial properties of lignin by-products obtained by organic solvent, neutral sulfite semichemical and kraft pulping were shown in a series of yeasts. Lignin can act as an inhibitor of growth ofSporobolomyces roseus, Candida tropicalis, Trichosporon cutaneum andCandida albicans. Oxidation of all lignin samples tested depresses their inhibitory effects.     

Terminal electron transport system (ETS)-activity in the sediment of Lake Balaton,Hungary

Terminal electron transport system (ETS)-activity of the sediment and plankton of Lake Balaton, the largest shallow lake of Central Europe was measured by tetrazolium-reduction biweekly during 1989–1990 and in the spring of 1991. Sediment proved to be enzymatically active to 30-35 cm down in the hypertrophic Keszthely Bay and to 15–20 cm down in the meso-eutrophic Siófok Basin. Sediment ETS-activity exceeded planktonic activity 15 to 24 fold.The total activity m^–2 showed one or two order of magnitude higher respiratory potential in Lake Balaton than needed for complete oxidation of the planktonic primary production; most of this potential was detected in the upper 3–5 cm sediment layer in springs. Incubations of cell-free homogenates of sediment bacteria showed that ETS remains active days after death of organisms at low temperature. Accumulated postmortem ETS-activity derived from the benthic diatoms, bacteria, plankton deposit and dead summer macrophytes seems to be responsible for the high ETS-activity of the sediment in the warming periods in springs. These enzyme fractions may contribute to the rapid oxidation of the alkaline, well-aerated lake.     

Lectins as markers of rumen epithelial cell differentiation

Summary Lectins of different carbohydrate specificities (GNA (Galanthus nivalis), con A (Canavalia ensiformis), VFL (Vicia faba), PSL (Pisum sativum), LCA (Lens culinaris), PNA (Arachis hypogaea; with or without prior neuraminidase treatment), WGA (Triticum vulgare), SBA (Glycine max), UEA-I (Ulex europaeus), LPA (Limulus polyphemus), BS-I B₄ (Bandeiraea simplicifolia, isolectin B₄)) were explored for use as differentiation markers of rumen epithelial cellsin vivo andin vitro. Lectins specific for mannose (GNA), mannose/glucose (con A, VFL, PSL and LCA),N-acetylglucosamine (WGA) or forN-acetylneuraminic acid (LPA) reacted generally with all types of rumen epithelial cell from both rumen tissue and cell culture. They were, therefore, not suitable markers of epithelial differentiation. SBA was unsuitable because, although it reacted with both tissue and cultured rumen epithelial cells, it was also bound to non-stratified areas of primary rumen epithelial cell cultures. Both BS-I B₄ and PNA (after neuraminidase treatment) had to be ruled out because they did not react with differentiated rumen tissue epithelial cells, although they did bind to both stratified and non-stratified cultured cells. In contrast, UEA-I reacted strongly with differentiated rumen epithelial cells both from rumen tissue and cell cultures and therefore appears to be a good general marker for rumen epithelial cell differentiation.     

The influence of ammonia on the growth and photosynthesis of Ruppia drepanensis Tineo from Doñana National Park (SW Spain)

In a laboratory experiment, Ruppia drepanensis Tineo seedlings from a brackish marsh in Southern Spain were grown at 20 and 30 °C, at three different nitrogen levels. These levels were obtained by the addition of a slow release fertilizer (23% NH₄NO₃ by weight) to a sediment mixture of sand and clay (3:1). Several morphometric parameters were recorded during the first five weeks of the experiment, and photosynthesis and respiration were measured after 7 weeks of growth. Results showed a significant reduction of growth and development with increasing nitrogen and temperature levels. Dark respiration increased strongly at high nitrogen levels. At the same time, net photosynthesis at 250 and 500 µE m^-2 s^-1, Pm, Km and LCP were not affected by either factor. We attribute these phenomena to ammonia toxicity, since relatively high total ammonia (NH₃ + NH_f4 ^p+) levels were found in the interstitial water.     

Labidocera aestiva and L. scotti in Tamiahua Lagoon,Veracruz, Mexico

Labidocera aestiva and L. scotti were found in the Tamiahua Lagoon, Veracruz, Mexico. Fleminger (1957) found that the populations of these species may overlap geographically, although L. aestiva has affinity to the Carolinian province and L. scotti to the Caribbean province. This study describes the seasonal behavior and succession of this species in the Tamiahua Lagoon, a brackish water system with a high marine influence. A qualitative and quantitative analysis of samples was made in March, July, and September 1985 and January 1986. L. aestiva was found in temperatures below 26 °C in a wide salinity range. At temperatures above 26 °C and up to 32 °C, L. aestiva was present also with euryhaline character. In the Tamiahua Lagoon these two species did not overlap during this study. Both species are considered temporary inhabitants of this estuarine system in the Western Gulf of Mexico.     

Crop/Weed gene flow:Cucurbita argyrosperma Huber andC. fraterna L. H. Bailey (Cucurbitaceae)

A mixed population of Cucurbita at Vado El Mow in northern Tamaulipas, Mexico showed an anomalous pattern of fruit bitterness. Some domesticated plants (C. argyrosperma andC. moschata) expressed cucurbitacin bitterness whereas some sympatric free-living plants produced non-bitter fruits. This reversal of typical cucurbitacin expression suggested gene flow between crop and weed at the site. Isozyme analysis provided little insight as to taxa involved in gene exchange, although progeny from a single free-living plant carried IDH allozymes that are associated with Mexican landraces ofC. pepo. Synthetic hybridization revealed that fertile F, hybrids are produced from crosses involvingC. fraterna as the pistillate parent andC. argyrosperma as the staminate parent. Interspecific crop/weed hybrids can produce viable progeny upon self-pollination or backcrossingto either parent, andF₂ families display normal allozyme segregation. Hybrid fertility, as indicated by pollen stainability, increases in progeny produced by backcrossingfrom theC. argyrosperma parent. Interspecific hybridfertility represents a potential for crop/weed gene flow that would be realized under natural conditions if pollen flow occurs betweenC. fraterna andC. argyrosperma in the fields of Tamaulipas. Oligolectic “squash bees” (Teponapis), efficientCucurbita pollen vectors, are present at the site. Thus, it is likely that natural interspecific crop/weed hybridization has occurred at Vado El Moro and this might at least partially explain the anomalous distribution of fruit bitterness among extant populations at the site.