Some effects of organic acid supplementation on utilization of ammonium compounds by three pathogenic fungi

Utilization of ammonium nitrogen byFusarium moniliforme Sheld.,Curvularia verruciformis Agarwal &Sahni andSclerotium rolfsii Sacc., with and without organic acid supplementation was studied. Ammonium utilization by these organisms generally improved with small amounts of organic acid supplementation except in the case ofC. verruciformis on ammonium chloride where fumaric acid was observed to suppress utilization. Effects of supplementation were seen to be dependent on the nature of the organic acid, the ammonium source used and the organism employed. Further evidence obtained by varying the quantities of succinic acid in ammonium chloride media showed that higher levels of supplementation gave increased growth of the fungi and prevented the pH from falling. It seems that these acids play a dual role as pH buffers as well as nutritional compounds.     

The nitrogen requirements ofGluconobacter,Acetobacter andFrateuria

The nitrogen requirements of 96Gluconobacter, 55Acetobacter and 7Frateuria strains were examined. Only someFrateuria strains were able to grow on 0.5% yeast extract broth or 0.5% peptone broth. In the presence ofd-glucose ord-mannitol as a carbon source, ammonium was used as the sole source of nitrogen by all three genera. With ethanol, only a fewAcetobacter strains grew on ammonium as a sole nitrogen source. Singlel-amino acids cannot serve as a sole source of carbon and nitrogen for growth ofGluconobacter, Acetobacter orFrateuria. The singlel-amino acids which were used by most strains as a sole nitrogen source for growth are: asparagine, aspartic acid, glutamine, glutamic acid, proline and alanine. SomeAcetobacter andGluconobacter strains deaminated alanine, asparagine, glutamic acid, threonine, serine and proline. NoFrateuria strain was able to develop on cysteine, glycine, threonine or tryptophan as a sole source of nitrogen for growth. An inhibitory effect of valine may explain the absence of growth on this amino acid. No amino acid is “essential” forGluconobacter, Acetobacter orFrateuria.     

Extracellular deamination of l-amino acids by Chlamydomonas reinhardtii cells

When grown in the light and in a Tris-acetate phosphate medium, cells of Chlamydomonas reinhardtii Dang. can use the following l-amino acids as a sole nitrogen source: asparagine, glutamine, arginine, lysine, alanine, valine, leucine, isoleucine, serine, methionine, histidine, and phenylalanine, whereas, in the absence of acetate, the cells only used l-arginine. The utilization system in the acetate medium consisted of an extracellular deaminating activity induced by l-amino acids; it took between 10 to 30 h before the system appeared in cells previously grown with ammonium. This deaminase activity was nonspecific, required an organic carbon source for its de-novo synthesis, and was sensitive to high ammonium concentration and light deprivation.Abbreviations HPLC high-performance liquid chromatography - TAP Tris-acetate-phosphate This work was supported by a grant of the CAICYT, Spain. The secretarial assistance of C. Santos and I. Molina is gratefully acknowledged.To whom correspondence should be addressed.     

Isolation and characterization of a marine methanogenic bacterium from the biofilm of a shiphull in Los Angeles harbor

A marine mesophilic, irregular coccoid methanogen, which shows close resemblance toMethanococcus sp., was isolated from the biofilm of shiphulls docked in Los Angeles harbor. Hydrogen plus carbon dioxide or formate served as substrates for methanogenesis in a mineral salt medium. The isolate did not use acetate and methanol as sole source of carbon and energy. The organism had an optimal pH range of 6.8–7.0 and a temperature optimum of 37°C. Elevated levels of sodium chloride were required for optimum growth. Optimum levels of total sulfide and magnesium chloride for growth were 1.0mm and 10mm respectively. The isolate used ammonia as nitrogen source. The concentration of 30mm ammonium chloride supported maximum growth of the isolate.     

Nitrogen and sulphur requirements of Colletotrichum inamdarii Lal

Summary Nitrogen and sulphur requirements ofColletotrichum inamdarii Lal isolated from the leaves ofCarissa carandas L. have been studied. DL-serine, L-asparagine and L-phenylalanine have been found to be of good nitrogen source followed by potassium nitrate, calcium nitrate, magnesium nitrate, DL-alanine, ammonium nitrate, glutamic acid, ammonium sulphate, DL-valine, aspartic acid, ammonium chloride, ammonium hydrogencarbonate, L-histidine and potassium nitrite. There was no growth in the absence of nitrogen.Sporulation was excellent on calcium nitrate and sodium nitrate, Very good on DL-serine, potassium nitrate, and magnesium nitrate. Good on L-asparagine, L-phenylalanine and ammonium oxalate. Fair on DL-alanine, DL-leucine, ammonium sulphate, DL-valine, ammonium chloride and L-histidine whereas poor on glutamic acid, aspartic acid, ammonium tartarate and ammonium nitrate. Few spores were observed on ammonium hydrogencarbonate but potassium nitrite did not show any sporulation.Amongst the sulphur compounds sodium bisulphate gave the best growth and good sporulation, followed by sodium thiosulphate, magnesium sulphate, ammonium sulphate and potassium sulphate. Thiourea gave negligible growth whereas it failed to grow on zinc sulphate and potassium persulphate.     

Utilization of oligosaccharides by three imperfect fungi

Summary The utilization of oligosaccharides (maltose, sucrose, lactose and raffinose) by three imperfect fungi viz.Alternaria tenuis Auct.,Colletotrichum capsici (Syd.)Butler &Bisby andColletotrichum gloeosporioides Penz. isolated from diseased leaves of tomato,Scindapsus pictus andPolyscias balfuriana respectively, was studied chromatographically. Except for lactose, all the sugars were utilizzed through a hydrolytic pathway and almost all proved to be a suitable source of carbon for the growth of fungi. Along with the utilization of sucrose, a simultaneous synthesis of an oligosaccharide was also observed in case of two species ofColletotrichum. C. gloeosporioides, however, also synthesized an oligosaccharide, maltotriose if it is grown in the medium containing maltose. During the utilization of raffinose, melibiose and fructose were detectted in the culture medium ofA. tenuis. Melibiose was further broken down into glucose and galactose by the two species ofColletotrichum.All the sugars were consumed from the media within 15 days except for lactose which persisted in the media even after 15 days.     

Kinetics,nutrition and inhibitor properties of basidiospore germination in schizophyllum commune

Summary The kinetics, nutritional requirements and inhibitor properties of basidiospore germination in the wood-rotting mushroom Schizophyllum commune were investigated. Measurements of changes in absorbancy and dry weight showed a lag period of approximately 15–20 hrs, followed by an abrupt increase in the rate of both processes. Individual basidiospore elongation also showed a lag phase and population changes were heterogenous in this regard.Carbohydrates active for basidiospore germination were grouped into four categories. Those sugars active between 15 and 20 hrs included glycogen, turanose, cellobiose, maltose, sucrose, glucose, fructose, mannose, galactose and xylose. Several sugar alcohols were only active between 30 and 60 hrs incubation and these included mannitol, sorbitol, ribitol, xylitol, arabitol, erythritol and glycerol. A third category of carbohydrates active for germination required prolonged incubation between 30 hrs and 7 days and included lactose, sorbose, raffinose, melezitose, trehalose, ribose and melibiose. Compounds without activity after 7 days included galactitol, inositol, acetate, succinate, gluconate, citrate, fumarate, rhamnose, fucose and inulin.Nitrogen sources active in basidiospore germination included complex organic nitrogenous substrates, asparagine, glutamine, arginine, urea and various ammonium salts.Germination was inhibited by cycloheximide, l-ethionine, p-fluoro-dl-phenylalanine, sodium azide, 2,4-dinitrophenol, phenylmercuric acetate and 2-deoxy-d-glucose. Alkali as a trapping agent arrested germination in glucose-(NH₄)₂SO₄ medium but was without ill-effect in glucose peptone broth.     

Short-term ammonium inhibition of nitrate utilization by Anacystis nidulans and other cyanobacteria

Ammonium at low concentrations caused a rapid and effective inhibition of nitrate utilization in the light by the cyanobacterium Anacystis nidulans without affecting the cellular level of nitrate reductase activity. The inhibition was reversible, and the ability of the cells to utilize nitrate was restored immediately after ammonium had been exhausted. The inhibitory effect was dependent on consumption by the cells of the added ammonium which was rapidly incorporated into amino acids. In the presence of L-methionine-d,l-sulfoximine (MSX) or azaserine, inhibitors of the glutamine synthetase-glutamate synthase pathway, ammonium did not exhibit any inhibitory effect on nitrate utilization. Ammonium assimilation, rather than ammonium itself, seems to regulate nitrate utilization in A. nidulans. Short-term inhibition by ammonium of nitrate utilization and its prevention by MSX were also demonstrated in the filamentous cyanobacteria Anabaena and Nostoc.Abbreviations MSX L-Methionine-d-l-sulfoximine     

Nitrogen requirements of certain isolates of alternaria tenuis auct

Three isolates ofA. tenuis isolated from the diseased leaves ofMangifera indica l. Musa paradisiaca l. andPsidium guajava l. were investigated. They were grown on different sources of nitrogen viz., potassium nitrate, sodium nitrate, calcium nitrate, ammonium nitrate, sodium nitrite, ammonium sulphate, ammonium chloride, glycine, DL-valine, L-glutamic acid, urea, thiourea, L-asparagine and peptone. They were also grown on the medium lacking nitrogen. A wide variation was observed in the growth and reproduction of the different isolates. The growth of all of them was good on potassium nitrate, calcium nitrate, glycine, DL-valine, L-glutamic acid, L-asparagine and peptone but the sporulation was satisfactory on calcium nitrate only. Sodium nitrite supported moderate growth of banana leaf isolate whereas there was no growth of the other two isolates. None of the organisms could grow on the medium lacking nitrogen as well as on thiourea. The results obtained with the isolates under study have been compared with those of earlier investigators and it has been clearly established that the different isolates ofA. tenuis could show marked differences in their nitrogen requirements.     

Biochemical properties of yeast l-asparaginase

Only a single l-asparaginase has been found in the yeast Saccharomyces cerevisiae. The enzyme is synthesized constitutively, and its functioning is not controlled by the products of its activity. The apparent K_m for the yeast l-asparaginase reaction is 2.5×10^–4 m. Activity is greatest at pH 8.5 and is unaffected by the ionic strength of reaction mixtures. l-Asparagine can serve as the sole nitrogen source for cell metabolism but cannot serve as the sole supply of carbon. Active l-asparaginase is necessary for the use of l-asparagine as a nitrogen donor for cell growth. This requirement suggests a possible way in which l-asparaginase-deficient strains of yeast or other organisms might easily be selected.G.E.J. was supported by U.S. Public Health Service Predoctoral Fellowship No. 5 F01 GM36,437.     

Carbon and nitrogen requirements of Fusarium oxysporum causing cotton wilt

Summary The present work was carried out to study the nutritional requirements of the cotton wilt-inducing fungus, i.e.Fusarium oxysporum on a synthetic liquid medium with regard to the carbon and nitrogen sources at varying concentrations in terms of the average mycelial dry weights.The optimum carbon requirements of the fungus ranged from 7000–8000 p.p.m. irrespective of the carbon source used in experiment. Carbon utilization was best on sucrose followed by maltose, starch, glucose, fructose and cellulose successively.The optimum nitrogen requirements of the fungus were 300 p.p.m. of nitrogen in the medium; nitrogen utilization was best on using nitrate-nitrogen followed by glycine, glutamic acid, ammonium nitrate, asparagine and ammonium sulphate.Maximum growth of the fungus took place on media containing a C/N ratio ranging between 22.8 and 25.7.Colour formation is correlated with varying either source or concentration of nitrogen and not carbon.     

Effect of different carbon and nitrogen sources on the growth and sporulation of Claviceps microcephal (Wallr) TUL.

The effect of different carbon and nitrogen compounds on growth and sporulation ofC. microcephala (Wallr.)Tul. causing ergot disease of Bajra has been studied. Nine different sources of carbon were used but cane sugar was found to be the best source for both, growth and sportulation of the fungus. Glucose, sucrose and maltose gave good growth but fair sporulation. Lactose and sorbitaol proved to be the poor sources. However, fungus failed to utilize starch, dextrin and mannitol.Nineteen nitrogen compounds were tried for the growth and sporulation of the fungus. Best growth and sporulation were supported by peptone and glycine. L-asparagine, DL-valine, Urea, magnesium nitrate and L-proline supported good growth and fair sporulation except DL-valine where it was excellent. Poor growth was obtained on L-isoleucin, ammonium sulphate, potassium nitrate,-alanine, ammonium chloride, DL-aspartic acid and DL-methionine. Fungus failed to utilize thio-urea.     

Effects of methylammonium and ofL-methionine-DL-sulfoximine on the growth and nitrogen metabolism ofPhaeodactylum tricornutum

Phaeodactylum tricornutum Bohlin grew well withL-methionine-DL-sulfoximine (MSX) as sole nitrogen source. Such growth helps to explain the lack of effect of MSX on ammonium assimilation by this organism. Methylammonium inhibited growth with nitrate or MSX as sole nitrogen source but not growth on ammonium. Methylammonium could not be metabolised byP. tricornutum but was accumulated in the cells, the concentration factor sometimes approaching 25,000. Ammonium addition, but not that of MSX or nitrate, displaced methylammonium from the cells and this displacement was followed by resumption of growth. Both methylammonium and ammonium inhibited the uptake of nitrate and nitrite by the cells but inhibition by methylammonium, in comparison with that by ammonium, required a higher concentration and a longer time to develop. Inhibition by methylammonium is shown to be associated with its accumulation by the cells. Methylammonium also prevented the disappearance of nitrate from the interior of the cells (presumably by nitrate assimilation) whereas ammonium did not. It is concluded that methylammonium and ammonium differ in the ways in which they inhibit nitrate metabolism inP. tricornutum.Abbreviation MSX L-methionine-DL-sulfoximine     

Ecological study of soil fungi of an agricultural field in Allahabad

Summary The soil fungi from an agricultural field in Allahabad where sugarcane is being grown for many years, have been isolated from various depths during different seasons and were identified. The inter-relations of chemical composition of soil and distribution of fungi is also being shown here.The techniques for the isolation and the study of the fungus flora was that ofGoddard modified bySaksena &Mehrotra. Soil samples were examined from 1–6 depths in three seasons of the year and were mechanically and chemically analysed.For the isolation, soil dilution plate method, a modification ofMenzies' method, direct method ofWaksman, Rossi Cholodny Burried slide technique, and screened immersion plate method, were followed Fifty five different species of microfungi belonging to Phycomycetes, Ascomycetes and Fungi — Imperfecti were isolated and identified. The moisture contents, hydrogen-ion concentrations, carbon, nitrogen, phosphorus, calcium, magnesium and iron, etc., of the soil samples from 1–6 inches depths, were also studied.Out of these 12 species covering 9 genera belonged to the Phycomycetes, nine genera of Ascomycetes and nine genera of Fungi Imperfecti were recorded.P. multicolor Grigorieva-Monoilova &Poradielova, andP. roqueforti Thom.,Gliocladium vermoesoni (Biourge)Thom. andMasoniella grisea (Smith)Smith were recorded for the first time from Indian Soil. A new varietyChaetominum nigricolor Ames var.simplex was also isolated.     

Effects of some carbon sources on growth and nitrogen fixation in the cyanobacteriumNostoc linckia

Glucose, fructose, sucrose, maltose, and lactose stimulated photoheterotrophic growth ofNostoc linckia (Roth.)Born. as well as its heterocyst frequency, chlorophyll and protein contents, ammoniacal nitrogen uptake and nitrogenase activities. Glucose, fructose and sucrose also supported slow chemoheterotrophic growth. α-ketoglutarate, pyruvate, ribose, succinate, acetate, sorbose and formate were inhibitory.     

Inorganic nitrogen source for autotrophic growth of Euglena mutabilis Schmitz

The effect of inorganic nitrogen source on population growth of Euglena mutabilis, an acidophillic benthic protozoa colonizing on the sediment of acid mine drainage, was investigated. Sodium nitrate, ammonium chloride, and ammonium sulfate were tested as nitrogen sources. The population density of E. mutabilis at equilibrium density cultivated in ammonium chloride‐ and ammonium sulfate‐containing media was 9–11 times higher than that in sodium nitrate‐containing medium at the optimal salt medium concentration. The population growth of E. mutabilis in ammonium sulfate‐containing medium was rapid and reached half of the equilibrium density after ca. 228 h, which was ca. 77 h earlier than that in ammonium chloride‐containing medium. Culture medium with ammonium sulfate as the nitrogen source achieved the highest maximum population density and the fastest growth rate among the three nitrogen salts used as nitrogen sources.     

Molecular analysis of inorganic nitrogen assimilation in yeasts

Assimilation of nitrate and various other inorganic nitrogen compounds by different yeasts was investigated. Nitrate, nitrite, hydroxylamine, hydrazine, ammonium sulphate, urea and L-asparagine were tested as sole sources of nitrogen for the growth of Candida albicans, C. pelliculosa, Debaryomyces hansenii, Saccharomyces cerevisiae, C. tropicalis, and C. utilis. Ammonium sulphate and L-asparagine supported the growth of all the yeasts tested except D. hansenii while hydroxylamine and hydrazine failed to support the growth of any. Nitrate and nitrite were assimilated only by C. utilis. Nitrate utilization by C. utilis was also accompanied by the enzymatic activities of NAD(P)H: nitrate oxidoreductase (EC 1.6.6.2) and NAD(P)H: nitrite oxidoreductase (EC 1.6.6.4), but not reduced methyl viologen-or FAD-nitrate oxidoreductases (EC 1.7.99.4). It is demonstrated here that nitrate and nitrite reductase activities are responsible for the ability of C. utilis to assimilate primary nitrogen.     

Leptographium piriforme — first record for Europe and of potential pathogenicity

Leptographium piriforme Greif, Gibas & Currah, described in 2006 from western Canada has recently been collected in Jaroszowiec in Poland. The ophiostomatoid fungus L. piriforme was isolated from fallen Pinus sylvestris L. shoots infested by Tomicus spp. Isolates were identified to species using morphological characteristics and nuclear ribosomal DNA sequences. Two-year-old P. sylvestris seedlings were wound-inoculated with one isolate of L. piriforme. Leptographium piriforme produced necrotic lesions in the phloem of the seedlings, but none of the plant inoculated with this fungus died. This is the first report of L. piriforme from Poland and entire Europe.     

Highly efficient production of <Emphasis Type="SmallCaps">d</Emphasis>-lactate by <Emphasis Type="Italic">Sporolactobacillus</Emphasis> sp. CASD with simultaneous enzymatic hydrolysis of peanut meal

Highly efficient d-lactate production by Sporolactobacillus sp. strain CASD was demonstrated in this study. Peanut meal was found to be a better nutrient than yeast extract, soybean meal, soybean peptone, corn steep, liquor beef extract, and ammonium sulfate in the production of d-lactate. To improve the utilization of peanut meal, the material was enzymatically hydrolyzed and simultaneously utilized as the nitrogen source in d-lactate fermentation. Very high d-lactate production (207 g/L) was obtained using 40 g/L of peanut meal in 30-L fed-batch fermentation, with the average productivity of 3.8 g/(L·h) and optical purity of 99.3%. The production of such a high concentration of optically pure d-lactate by strain CASD, with the simultaneous enzymatic hydrolysis of peanut meal and fermentation, represents a new cost-efficient and integrated method for d-lactate production using agricultural by-products.     

Degradation of p-nitrophenol and pentachlorophenol mixtures by Sphingomonas sp. UG30 in soil perfusion bioreactors

The degradation of mixtures of pentachlorophenol (PCP) and p-nitrophenol (PNP) were evaluated in pure cultures of Sphingomonas sp. UG30, statically incubated soils (60% water-holding capacity) and soil perfusion bioreactors where encapsulated cells of UG30 were used as a soil inoculant. In pure-culture studies, conditions were optimized for mineralization of PCP and PNP mixtures at concentrations of 30 mg l⁻¹ each. Optimum in vitro mineralization of PCP and PNP mixtures by UG30 was facilitated using ammonium phosphate as a nitrogen source, while inhibition was observed with ammonium nitrate. The bioreactor system used columns containing soil treated with mixtures of 100, 225 or 500 mg kg⁻¹ of PCP and PNP. Rapid dissipation of both substrates was observed at the 100 mg kg⁻¹ level. Inoculation with UG30 enhanced PCP degradation at the 100 mg kg⁻¹ level in bioreactors but not in static soil microcosms. At higher PCP and PNP concentrations (225 mg kg⁻¹), occasional complete degradation of PNP was observed, and PCP degradation was about 80% compared to about 25% in statically incubated soils after 20 days at 22°C. There was no additional degradation of the PCP and PNP mixtures attributable to inoculation with encapsulated cells of UG30 in either soil system at concentrations of 225 or 500 mg kg⁻¹. Journal of Industrial Microbiology & Biotechnology (2000) 25, 93–99. Received 25 February 2000/ Accepted in revised form 07 June 2000