Microbial transformation of pyridine derivatives: alpha-picolinate metabolism by a gram-negative coccus.
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Gram-Negative Aerobic Bacteria↗
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Results for “Soil acidity”
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Effect of H+ ion activity and Ca2+ on the toxicity of metals in the environment.
The role of acidity in determining and restricting plant distribution and performance is discussed. In soils especially, a key effect of H+ ion concentration is on the solubility of potentially toxic heavy metals such as aluminum, managenese, zinc, iron, copper, and nickel. Al has been reported from many studies since the 1920's as the key determining toxic factor in acid soils. Some acid-tolerant species have been shown to be especially tolerant of Al, and mechanisms of tolerance have been suggested. Mn is also a commonly toxic factor at soil pH less than 5.0. Calcium has been shown to alleviate Mn toxicity. Low pH soils are also generally low in Ca, K, Na, and P; all essential major elements for plant growth. In lakes and marine situations acidic waters are uncommon as the waters are buffered. Calcium is again ameliorative of metal toxicities. The pH, redox, and valency state are critical in determining nutrient availability and metal speciation. Recent increases in the H+ ion content of precipitation have caused increased acidities of freshwater lakes in Scandinavia and eastern North America, which have depleted biota, including fish populations.
Animals↗
The distribution of geophilic dermatophytes in Kenyan soils.
Two hundred and eighty one soil samples from different provinces of Kenya were examined for dermatophytes by the hair baiting technique. Dermatophytes were recovered from 84 samples. Microsporum gypseum constituted 75.8% of the total isolates while Keratinomyces ajelloi and M. cookei formed 21% and 3.2%, respectively. The distribution of the dermatophytes was influences by soil pH, being more prevalent in acidic than in alkaline soils.
Arthrodermataceae↗
Muramic acid as a measure of microbial biomass in estuarine and marine samples.
Muramic acid, a component of the muramyl peptide found only in the cell walls of bacteria and blue-green algae, furnishes a measure of detrital or sedimentary procaryotic biomass. A reproducible assay involving acid hydrolysis, preparative thin-layer chromatographic purification, and colorimetric analysis of lactate released from muramic acid by alkaline hydrolysis is described. Comparison of semitropical estuarine detritus, estuarine muds, and sediments from anaerobic Black Sea cores showed muramic acid levels of 100 to 700 microng/g (dry weight), 34 microng/g, and 1.5 to 14.9 microng/g, respectively. Enzymatic assays of lactate from muramic acid gave results 10- to 20-fold higher. Radioactive pulse-labeling studies showed that [14C]acetate is rapidly incorporated into muramic acid by the detrital microflora. Subsequent loss of 14C, accompanied by nearly constant levels of total muramic acid, indicated active metabolism in procaryotic cell walls.
Acetates↗
Studies on phosphate-solubilizing bacteria in soil and rhizosphere of different plants. I. Occurrence of bacteria, acid producers, and phosphate dissolvers.
Occurrence of bacteria (total), acid producing and phosphate dissolving micro-organisms in soil, rhizosphere, and rizoplane of Egyptian cotton, peas, or maize during their different growth phases was studied. The rhizosphere effects were generally positive and differed according to type of plant, growth phase of each special plant, and type of micro-organism under study. The high densities of bacteria, acid-producers, and phosphate-dissolvers in the rhizoplane samples suggest the conclusion that roots of the studied plants are colonized with these soil micro-organisms. The role of the micro-organism and the mechanism of the noted colonization is not fully understood yet. However, the presence of high numbers of bacteria in the rhizosphere zones of all plants is undoubtedly important, since they may convert organic and inorganic substances into available plant nutrients. The acidproducing organisms were greatly stimulated in the rhizosphere of all plants. Consequently, the production of acid, especially in alkaline soils such as in Egypt, may directly or indirectly react with insoluble inorganic compounds, converting their nutrient elements into available forms for the growing plants. But not all acid-producers are considered as phosphate-dissolvers. Therefore, the presence of high numbers of phosphate-dissolving bacteria in the rhizophere zones may explain how the growing plants can obtain their requirements in such alkaline soils.
Bacteria↗
Effect of some medicaments on the oxygen uptake of the spores of some soil fungi.
Nystatin, riboflavin, ascorbic acid, captan, indoleacetic acid, and colchicin were tested in two concentrations for their effect on the oxygen uptake of the spores of Mucor racemosus, Cladosporium tenuissimum, Cochliobolus spicifer, and Macrophomina phaseoli. Nystatin and captan inhibited the oxygen uptake of the spores of all fungi used, and this inhibitory effect increases with increasing concentration. On the other hand, riboflavin, ascorbic acid, indoleacetic acid, and colchicin were found to have a stimulating effect. Increasing the concentration of these medicaments to the double concentration causes a decrease in the oxygen uptake, except in the case of ascorbic acid where the reverse occurs.
Ascorbic Acid↗
Dynamics of microbial population in soil as influenced by simazine and ecological factors.
Simazine, even at normal rates of application, showed toxicity to bacteria fungi. It was less toxic to actinomycetes, since toxicity up to 20 ppm of the herbicide was not observed. On the contrary, the normal rate of simazine stimulated both Azotobacter and actinomycetes population. The interaction of simazine with soil ecological factors, such as temperature, moisture, pH, and organic matter, affected soil microbial population differently. Simazine was relatively less toxic to bacteria under acidic and alkaline conditions of soil; they were not affected at 15 degrees C. Actinomycetes were comparatively not adversely affected even with 200 ppm of simazine under high soil moisture regime. The stimulatory effect of simazine on Azotobacter was also confirmed under different ecological conditions. The incorporation of 2 per cent of organic matter in soil mitigated the toxicity of simazine in respect to soil fungi. Simazine also appeared to be less toxic to soil fungi at lower temperatures, under acidic and alkaline conditions of soil, as well as under high moisture regime.
Actinomycetales↗
Fate of chloroalkylene-9-14C in carrots, sugar beets, and soil under outdoor conditions.
Immediately after application of chloroalkylene-9-14C to soil (1.32 ppm, based on dry weight of soil in the upper layer of 0 to 10 cm) under outdoor conditions, carrots were sown; in the following year, sugar beets were grown. About 80% of the radioactivity applied volatilized within one vegetation period. Most of the remaining radioactivity was still in the upper soil layer; 0.8% had dispersed to a depth of 40 cm, and 3.3% was taken up by the carrot plants. In the second year, no more decreases of soil residues was observed; uptake by sugar beets was 0.1% of the applied radioactivity. In the first year, the residues in the upper soil layer consisted of 41% unchanged chloroalkylene-9, 19% soluble metabolites, and 40% unextractable residues; the amount of unextractable residues rose to 68% in the second year. The following conversion products were characterized in the soil extracts: a monohydroxylated dichlorobiphenyl, a monomethoxylated dichlorobiphenyl, and two isomeric monohydroxylated, monoisopropylated dichlorobiphenyls; in carrot roots, a monomethoxylated dichlorobiphenyl was detected. Conjugates occurring in the soil yielded, after acid hydrolysis, a monohydroxylated dichlorobiphenyl among other compounds.
Hydrolysis↗
Studies on the adsorption of selected polychlorinated biphenyl isomers of several surfaces.
The adsorption-desorption characteristics of three selected PCB isomers on a soil and some of its constituents have been determined. The extent of adsorption for all surfaces follows the sequence hexachloro greater than tetrachloro greater dichloro for the isomers chosen. For an individual isomer, the adsorption rates increase in the following sequence: Del Monte, sand, illite clay, Woodburn soil, and humic acid. These results are discussed relative to environmental transport of the chemicals.
Adsorption↗
[Humic acid destruction by the microorganisms of irrigated soils].
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Actinomycetales↗
Differential isolatoion of Pythium species from soil by means of selective media,temperature, and pH.
Pythium aphanidermatum, with an optimum temperature for growth at 35C, grew welland was readily isolated from soil on pimaricin-vancomycin medium (MPVM) when incubated for 24h at 38-40C. The pH of the medium affected recovery; maximum numbers developed above pH 6.0. Other Pythium spp. were recovered on MPVM at 20-25C, but were excluded by incubation at 38-40C. These Pythium spp. included P. ultimun, P. paroecandrum, P. irregular, P. mamillatum, and an unidentified Pythium sp. These species grew well and were readily siolated from soil on gallic acid medium (GAM) when incubated for 24-8h at 20 C.P. aphanidermatum and P. myriotylum grew from mycelium on GAM, but their oospores did not germinate nor could they be isolated from soilon this medium. P. myriotylum grew well on MPVM, but was only rarely isolated, evenfrom soils with known high potential for disease caused by P. myriotylum. Propagules of Pythium were enumerated by a plate-dilution frequency method or by a smearplateethod is valuable for studies on the ecology, survival, and inoculum potential in soils with mixed populations of P. aphanidermatum and other Pythium spp.
Culture Media↗
Complete genomes of 22 bacterial strains isolated from polluted soil microbiota via enrichment on PFAS as a sole carbon source.
A total of 22 bacterial strains were isolated from PFAS-contaminated soil (Veneto, Italy), after a 5-month enrichment using perfluorooctanoic acid and heptafluorobutyric acid. Whole genomes were sequenced and screened with a curated database of dehalogenase-related proteins. All genomes showed potential for fluorinated compound transformation.
Veneto region, Italy↗
Relationship between amino acid production and phosphate-dissolving capacity of bacteria.
The ability of soil bacteria to produce amino acids (alanine, aspartic acid, leucine, arginine, glutamic acid, and lysine) was related to the ability to dissolve inorganic phosphate. With the exception of lysine, amino acid production increased with increasing ability to dissolve phosphate.
Alanine↗
The metabolic fate of N-isopropyl-N-phenyloxamic acid in the rat and the milk goat.
Rats excreted the 14C from a single oral dose of N-isopropyl-N-[14C]phenyloxamic acid [I, a soil metabolite from 2-chloro-N-isopropylacetanilide (propachlor)] in approximately equal quantities in the urine (49.2%) and feces (48.2%). A milking goat given daily oral doses of [14C]-I (1 mg of I three times daily) excreted more 14C in the feces (56.6%) than it excreted in the urine. From both species, I accounted for 97 to 100% of the urinary 14C, and all of the 14C that was extractable from the feces (73 to 75% of the 14C in feces was extractable with methanol). Goat milk samples collected 16 hr after the last dose contained no detectable 14C. Tissue residues of 14C were determined.
Amino Acids↗
Structural changes associated with poliovirus inactivation in soil.
The loss of infectivity of poliovirus in moist and dried soils was a result of irreversible damage to the virus particles. The damage included (i) dissociation of viral genomes and capsids and (ii) degradation of viral ribonucleic acid (RNA) in the soil environment. Under drying conditions, capsid components could not be recovered from the soils. Further studies in sterile soils indicated that, under moist conditions, the viral RNA was probably damaged before dissociation from the capsid. However, in sterile, dried soil, RNA genomes were recovered largely intact from the soil. These results suggest that polioviruses are inactivated by different mechanisms in moist and drying soils.
Adsorption↗
Five novel Paenibacillus species from the plant rhizosphere: Paenibacillus corni sp. nov., Paenibacillus vaccinii sp. nov., Paenibacillus ericacearum sp. nov., Paenibacillus polytrichii sp. nov., and Paenibacillus artemisiae sp. nov.
Bacterial strains were isolated from different locations and screened for plant growth promoting (PGP) features. Comparative analyses of the 16S gene sequences of 5 of the strains indicated taxonomic relatedness within the genus Paenibacillus. A polyphasic taxonomic approach was employed to study the strains in detail to clarify their phylogenetic position. Genome-based analyses, including digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI), revealed values consistently below the accepted species delineation thresholds when compared with closest relatives of each strain. Additionally, the strains showed clear differences in their physiological and biochemical profiles to the type strains of the closest related species. A notably diverse set of genes potentially involved in plant growth promotion was detected in all strains. With respect to the analyses reported here, the following new names are proposed: Paenibacillus corni sp. nov., with AK-167T as the type strain (= LMG 34403T = DSM 121689T); Paenibacillus vaccinii sp. nov., with AK-264T as the type strain (= LMG 34404T = DSM 121714T); Paenibacillus ericacearum sp. nov., with AK-265T as the type strain (= CCM 6913T = LMG 34405T = DSM 121715T); Paenibacillus polytrichii sp. nov., with AK-286T as the type strain (= CCM 9614T = LMG 34406T = DSM 121716T); and Paenibacillus artemisiae sp. nov., with DT-106T as the type strain (= LMG 34409T = CCM 9610T = DSM 121690T).
Paenibacillus↗
Isolation and characterization of uracil-degrading clostridia from soil.
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Biodegradation, Environmental↗
4-(p-Nitrobenzyl)pyridine as a spray reagent for the thin-layer chromatographic detection of dimethyl tetrachloroterphthalate herbicide.
The developed thin-layer chromatogram of DCPA (Dacthal) is sprayed with 4-(p-nitrobenzyl)pyridine chromogenic reagent followed by ammonium carbonate solution. The chromatogram is then heated in an over at 130 degrees C for 20 minutes. When cool, the chromatogram is sprayed with tetraethylenepentamine reagent. DCPA spots appear blue against a white background. The sensitivity of this test is about 1 microgram. The procedure is useful to detect DCPA in water and in soil.
Chromatography, Thin Layer↗