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At least 451 records · Page 25Linked to original sources
PubMed1991

Microbial agents for decolorization of dye wastewater.

Colored dye wastewater presents a formidable task for biological treatment. Depending on how it is generated, wide pH spans and high salt concentrations such as chloride ion often add to the difficulties. Systematic screening for dye decolorizing and/or degrading bioagents from soil and water samples discovered fungi which show dramatic color removal capability (Shen, et al., 1990). One example shows that up to 99% reduction of light absorption at characteristic wavelength of a red dye (200 mg/L) could be obtained within 48 hours. This ability does not appear to be specific toward dyes targeted for action. It clarifies, often beyond detection by naked eyes, a repertoire of colored wastewater samples. These results appeared to be insensitive to wide variations in pH and salt concentration and, they are not limited to one particular fungal species or genus either upon further investigation. This dye adsorption mechanism may be of great significance in uncovering new methods for bio-removal or bio-recovery of dye substances in wastewater.

Journal Article↗
PubMedDate not supplied

Selective primary health care: strategies for control of disease in the developing world. XVII. Hookworm infection and anemia.

Approximately one-quarter of the world's population is infected with either Ancylostoma duodenale or Necator americanus. Humans transmit the hookworm by fecal contamination of the soil. The eggs hatch and the larvae may survive several months in warm, damp soil. Humans are infected when the larvae penetrate the skin and migrate through the body to the intestines, where the median survival time of the hookworm is one year. The loss of red blood cells into the gut is proportional to the worm load. Symptoms result from iron deficiency anemia and protein loss caused by a heavy worm burden. The peak age-specific prevalence of infection occurs in adult life, but only a small proportion of those infected ever become symptomatic. Possible control measures include chemotherapy to reduce the intensity of infection and the transmission potential and sanitation.

Anemia, Hypochromic↗
PubMed2003

[Effects of different P sources on phosphatase activity of mycorrhizosphere of red clover inoculated with AME].

Experiments were carried out to study the effects of P sources on phosphatase activity of rhizosphere and mycorrhizosphere of red clover inoculated with Glomus mosseae, and cultural system with three compartments was applied. The plants were harvested after 8 weeks, and measured for dry weight and P contents as well as soil phosphatase activity of root and hyphal compartment. The results showed that acid phosphatase activity was higher than alkaline phosphatase activity, and both of them were increased slightly after inoculation, especially supplied with organic phosphorus (Na-phytate). Acid phosphatase activity was higher than alkaline phosphatase in the mycorrhizosphere of all inoculated treatments. The dry weight, P content and total P uptake of the plants increased significantly after inoculating mycorrhizal fungus. The amount of P uptake by hyphae accounted for 43.1% of total P uptake of plants under applying KH2PO4, while the value was 60.8% under applying Na-phytate.

Acid Phosphatase↗
PubMed2005

[CO2 concentration character in broad-leaved Korean pine forest of Changbai Mountains].

The CO2 concentration in broad-leaved Korean pine forest of Changbai Mountains was measured continuously with a CO2 infra-red analyzer in 2003. The results showed that the CO2 concentration in the forest had striking characteristics of temporal-spatial variations, which were mainly influenced by the physiological processes of plants, soil respiration, and intensity of turbulence exchange. In growing season, the daily maximum and minimum CO2 concentration appeared mostly on the surface floor at about 5:00 in the early morning and at canopy location at about 15:00 in the afternoon, respectively. There was an obviously process of forest CO2 emission when the inversion broke at dawn. The average CO2 concentration in forest was 377 micromol x mol(-1) in 2003, the maximum of monthly average appeared in January as 388 micromol x mol(-1), and the minimum of monthly average appeared in August as 352 micromol x mol(-1). The forest acted as CO2 source in night time and turned to sink in daytime, during growing season. In non-growing season, the forest acted as CO2 source in both daytime and night time, but still had a clear evidence of CO2 assimilation at noon, with canopy location during non-growing season.

Air↗
PubMed1988

Characterization of 15 selected coccal bacteria isolated from Antarctic rock and soil samples from the McMurdo-Dry Valleys (South-Victoria Land).

Approximately 1500 cultures of microorganisms were isolated from rocks and soils of the Ross Desert (McMurdo-Dry Valleys). From these, 15 coccoid strains were chosen for more detailed investigation. They were characterized by morphological, physiological and chemotaxonomical properties. All isolates were Gram-positive, catalase-positive and nonmotile. Six strains showed red pigmentation and could be identified as members of the genera Micrococcus (M. roseus, M. agilis) or Deinococcus. In spite of their coccoid morphology, the remaining nine strains had to be associated with coryneform bacteria (Arthrobacter, Brevibacterium), because of their cell wall composition and G+C ratios. Most of the strains were psychrotrophic, but one strain was even obligately psychrophilic, with a temperature maximum below 20 degrees C. Red cocci had in vitro pH optima above 9.0 although they generally originated from acid samples. Most isolates showed a preference for sugar alcohols and organic acids, compounds which are commonly known to be released by lichens, molds and algae, the other components of the cryptoendolithic ecosystem. These properties indicate that our strains are autochthonous members of the natural Antarctic microbial population.

Antarctic Regions↗
PubMedDate not supplied

Influence of temperature and pH on the nonenzymatic reduction of triphenyltetrazolium chloride.

The effects of temperature and pH on the nonenzymatic (chemical) reduction of triphenyltetrazolium chloride (TTC) to triphenyl formazan (TF) in cheese whey and municipal solid waste compost samples were studied. Ten different incubation temperatures and 13 pH levels were tested. The study showed that the TTC could be reduced nonenzymatically at high temperatures and/or under alkaline pH conditions. The nonenzymatic TTC reduction was observed at pH values greater than 9.5 and 11.0 for the cheese whey and compost, respectively. The TTC chemical reduction rate followed the same trend in both media. The TF content increased with increasing the pH value, reaching its maximum at a pH of 12, then decreased and was not detected at a pH of 13. The TTC was also reduced nonenzymatically at temperatures higher than 70 and 85 degrees C for cheese whey and compost, respectively. Evaporation did not seem to have any significant effect on the TTC chemical reduction since less than 3% of water content was lost at a temperature of 100 degrees C. It was noticed that the TF yield in cheese whey samples was higher than that in compost samples. This was due to the higher moisture content of cheese whey and the presence of copper in the compost samples, which reacted chemically with the TF causing reduction in the red color. For a given incubation period, the effect of pH on the TTC chemical reduction was more significant than the effect of incubation temperature (at a 2 h incubation period, 57.5% and 17.9% of the TTC were chemically reduced at a pH of 12 compared to 10.9% and 7.7% at an incubation temperature of 100 degrees C, for cheese whey and compost, respectively). Among the six metals tested (Ca, Cu, K, Na, Ni, and Zn) only Cu affected the color intensity of the TF. The activation energy of the TTC chemical reduction was 168,808 and 239,102 J/mol in cheese whey and municipal solid compost, respectively. For dehydrogenase activity measurement, the pH of the samples and the incubation temperature should not be higher than 9 and 60 degrees C in order to ensure that the TTC reduction is caused only by the biochemical reaction. Measuring the color intensity of TF in waste samples that contain copper could give misleading results as a result of the formation of formazan copper complex, which reduces the red color.

Animals↗
PubMed1997

Root colonization of different plants by plant-growth-promoting Rhizobium leguminosarum bv. trifolii R39 studied with monospecific polyclonal antisera.

Monospecific polyclonal antisera raised against Rhizobium leguminosarum bv. trifolii R39, a bacterium which was isolated originally from red clover nodules, were used to study the colonization of roots of leguminous and nonleguminous plants (Pisum sativum, Lupinus albus, Triticúm aestivum, and Zea mays) after inoculation. Eight weeks after inoculation of soil-grown plants, between 0.1 and 1% of the total bacterial population in the rhizospheres of all inoculated plants were identified as R. leguminosarum bv. trifolii R39. To characterize the associative colonization of the nonleguminous plants by R.leguminosarum bv. trifolii R39 in more detail, a time course study was performed with inoculated roots of Z. mays. R. leguminosarum bv. trifolii R39 was found almost exclusively in the rhizosphere soil and on the rhizoplane 4 weeks after inoculation. Colonization of inner root tissues was detected only occasionally at this time. During the process of attachment of R. leguminosarum bv. trifolii R39 to the rhizoplane, bacterial lipopolysaccharides were overexpressed, and this may be important for plant-microbe interaction. Fourteen weeks after inoculation, microcolonies of R. leguminosarum bv. trifolii R39 were detected in lysed cells of the root cortex as well as in intracellular space of central root cylinder cells. At the beginning of flowering (18 weeks after inoculation), the number of R. leguminosarum bv. trifolii R39 organisms decreased in the rhizosphere soil, rhizoplane, and inner root tissue.

Antigens, Bacterial↗
PubMed1981

[Morphologic, cultural, and biochemical properties of cultures of Pseudomonas aeruginosa isolated from patients, animals, and the environment].

The properties of 279 Ps. aeruginosa strains were studied in 70 tests. The use of a synthetic peptone-free mineral medium for the determination of sugar oxidation was shown to have advantages over the use of liquid Giess' media. Ps. aeruginosa cultures isolated from human patients, animals, soil and water were characterized by a number of common signs, irrespective of their origin. The strains isolated from human patients were resistant practically to all antibiotics widely used in clinical practice; the cultures isolated from soil and water retained their sensitivity to antibiotics; the strains isolated from animals retained sensitivity to some antibiotics. To identify Ps. aeruginosa in practical bacteriological laboratories, the following parameters should be determined: mobility; the character of growth in Levine's and Ploskirev's media; ability to grow at 42 degrees C and 4 degrees C; the fermentation of carbohydrates in Olkenitsky's medium and their oxidation in a mineral medium; indole and hydroxide sulfide production; the methyl red and Voges--Proskauer reaction; the presence of pigments, oxidase, catalase, gelatinase, nitrate reductase and arginine dehydrolase, urease; resistance to antibiotics.

Animals↗
PubMed2000

A comparison of enumeration methods for culturable Pseudomonas fluorescens cells marked with green fluorescent protein.

The detection of bacteria in environmental samples using genetic markers is valuable in microbial ecology. The green fluorescent protein (GFP) reporter gene was studied under nutrient starvation conditions at 4 degrees C, 23 degrees C and 30 degrees C in Pseudomonas fluorescens R2fG1 cells tagged with a red-shifted gfp. Fluorescence intensity was not significantly different in cells maintained in a buffer for at least 48 days at all the tested temperatures. gfp-Tagged R2fG1 cells were introduced into bulk soil microcosms and soil microcosms with wheat seedlings. GFP-marked cells were enumerated immediately after inoculation into soil and again in soil and root samples after 10 days. Counts of culturable colonies were obtained from drop plates using 5-microl aliquots of serial dilutions viewed with an epifluorescent microscope. Traditional spread plates (using 100-microl aliquots) and the most-probable-number (MPN) method using a spectrofluorometer were also used to enumerate the GFP-marked Pseudomonas cells in soil, rhizosphere and rhizoplane samples. Microcolonies were visualized on root surfaces under the epifluorescent microscope after immobilizing in agar and incubation for 24 h. Counts from traditional spread plates were significantly higher (P<0.05) than the population estimates of the MPN method for all treatments at any sampling time. Counts using the drop plate method, however, were not significantly different (P<0.05) except in one treatment, and provided similar estimates in half the time of spread plates and at an estimated third of the cost.

Bacteriological Techniques↗
PubMed1987

Evidence for genetic exchange and recombination of Rhizobium symbiotic plasmids in a soil population.

A soil population of 16 Rhizobium leguminosarum bv. trifolii isolates was characterized by using three Sym (for symbiotic) plasmid-specific DNA hybridization probes: (i) an R. leguminosarum bv. trifolii-specific, repeated-sequence probe; (ii) a nifHDK gene probe, and (iii) a nod gene probe. A predominant Sym plasmid family was identified among the isolates. Three other unrelated Sym plasmid families were also identified. The isolates were also classified either by using a chromosomal DNA hybridization probe or by serological relatedness to 25 different R. leguminosarum bv. trifolii antisera. With either method, it was possible to group the 16 soil isolates into identical or related families. However, the correlation between the two techniques was not high. Irrespective of the means used to classify the bacterial host strain, it was possible to identify the same Sym plasmids in unrelated strains, as well as unrelated Sym plasmids in identical host strains. These data indicate that, within this soil population, there has been genetic exchange of Sym plasmids, and in one instance the hybridization pattern indicates that in vivo recombination of two different Sym plasmids may have occurred. Symbiotic effectiveness tests on red, strawberry, and subterranean clovers clearly differentiated the isolates. In general, the pattern of response was similar within groupings on the basis of Sym plasmid and chromosomal profiles but different between such groups.

Journal Article↗
PubMed1965

Pigment production from tryptophan by an Achromobacter species.

Duerre, John A. (University of North Dakota, Grand Forks), and Patrick J. Buckley. Pigment production from tryptophan by an Achromobacter species. J. Bacteriol. 90:1686-1691. 1965.-A microorganism was isolated from the soil near the University of North Dakota. Biochemical and morphological characteristics indicated that this organism would best be classified as a member of the family Achromobacteraceae, genus Achromobacter, species unknown. The organism produced a red pigment when grown in a medium containing yeast extract and tryptophan. The pH optimum for pigment production was about 8.0 and the optimal temperature was 25 C. During a study of the nutritional requirements for growth and pigment production, it was found that the organism would grow and produce pigment in a medium containing tryptophan and nucleosides, but the rate of both growth and pigment formation in this medium was slower than that observed with tryptophan and yeast extract. The organism grew well in the presence of acid-hydrolyzed casein and nucleosides without producing pigment, indicating that the pigment is not necessary for growth. Resting-cell experiments definitely established tryptophan as the sole exogenous requirement for pigment production. The pigment was extracted from yeast extract-tryptophan medium with chloroform. Thin layer chromatographic analysis of the crude pigment extracted from this medium revealed the presence of two other pigments in addition to the major red pigment. One of these was a highly fluorescent orange pigment and the other a pink pigment. Only the red pigment was produced by resting cells in the presence of tryptophan alone. This pigment served as an electron acceptor when coupled with formic dehydrogenase, indicating its possible function as an oxidation-reduction pigment. The oxidized pigment had absorption peaks at 506 and 304 mmu. The peak at 506 mmu disappeared upon reduction with sodium sulfite. Shaking the reduced pigment in air proved to be an unsatisfactory method for returning the reduced pigment to the oxidized, colored state.

Alcaligenes↗
PubMed2005

Bacillus subtilis is a potential degrader of pyrene and benzo[a]pyrene.

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of compounds that pose many health threats to human and animal life. They occur in nature as a result of incomplete combustion of organic matter, as well as from many anthropogenic sources including cigarette smoke and automobile exhaust. PAHs have been reported to cause liver damage, red blood cell damage and a variety of cancers. Because of this, methods to reduce the amount of PAHs in the environment are continuously being sought. The purpose of this study was to find soil bacteria capable of degrading high molecular weight PAHs, such as pyrene (Pyr) and benzo[a]pyrene (BaP), which contain more than three benzene rings and so persist in the environment. Bacillus subtilis, identified by fatty acid methyl ester (FAME) analysis, was isolated from PAH contaminated soil. Because it grew in the presence of 33 microg/ml each of pyrene, 1-AP and 1-HP, its biodegradation capabilities were assessed. It was found that after a four-day incubation period at 30 degrees C in 20 microg/ml pyrene or benzo[a]pyrene, B. subtilis was able to transform approximately 40% and 50% pyrene and benzo[a]pyrene, respectively. This is the first report implicating B. subtilis in PAH degradation. Whether or not the intermediates resulting from the transformation are more toxic than their parent compounds, and whether B. subtilis is capable of mineralizing pyrene or benzo[a]pyrene to carbon dioxide and water, remains to be evaluated.

Bacillus subtilis↗
PubMed1984

Effect of aponin, a substance from a green alga Nannochloris species, on the spore germination of two fungi.

Fungistasis which occurs in soil has also been reported to exist in seawater. Nannochloris sp. (Chlorophyta) found along the west coast of Florida, has been shown to elaborate a compound which is cytolytic towards Ptychodiscus brevis, the Florida red tide organism. Aponin, a chloroform extract containing the cytolytic compound or compounds, was tested on the spore germination of two fungi, Dendryphiella salina, a facultative marine organism and Curvularia sp. a terrestrial one. Aponin was stimulatory towards D. salina at all concentrations tested, while Curvularia sp. was stimulated at the highest concentration used but inhibited at the lower concentrations. The culture age of the two fungi did not alter the relative sensitivity of both fungi towards aponin but the germination percentage of Curvularia sp. was affected by the culture age. An aqueous extract of Nannochloris sp. was also tested on the two fungi and was shown to be inhibitory to both. The results seem to indicate that more than one compound from Nannochloris sp. is capable of affecting spore germination indicating that this alga might be playing a role in the reported fungistasis in seawater. Gulf seawater was tested and found to have little if any fungistatic activity.

Chlorophyta↗
PubMed2000

Seasonal patterns of carbohydrate reserves in red spruce seedlings.

We studied seasonal dynamics of carbohydrate storage in red spruce (Picea rubens Sarg.) seedlings by measuring starch and sugar concentrations of old needles (>/= one year old), new needles (< one year old), stems, and roots in two stands in the Green Mountains of Vermont. Although the two stands differed in many site characteristics including percent slope, aspect, soil type, drainage, and 564 m in elevation, concentrations and seasonal patterns of carbohydrates were similar for the two stands. For all tissues, starch concentrations peaked in late spring, declined through summer, and reached a minimum in winter. Sugar concentrations were greater than starch concentrations in all months except May and June. Sugar concentrations peaked in winter, and old needles showed a significant increase in sugar concentration between February and March. This increase in sugar concentration occurred without any reduction in localized starch concentrations or reductions in sugar or starch concentrations in new needles, stems or roots. Because March measurements were made toward the end of a prolonged thaw, a time when increases in photosynthesis have been documented for red spruce, it is likely that the March increase in sugar concentrations resulted from photosynthesis during the thaw. Compared with stems and roots, needles generally contained the highest concentration of carbohydrates and exhibited the greatest seasonal change in carbohydrate concentration. Needles were also the largest reservoir of carbohydrates throughout the year, especially during winter. Because of the critical roles of needles in photosynthesis and storage of carbohydrates, we conclude that any factors that disrupt the accumulation or availability of carbohydrates in red spruce needles will greatly alter plant carbon relations.

Journal Article↗
PubMed2003

Toxicity of eight polycyclic aromatic compounds to red clover (Trifolium pratense), ryegrass (Lolium perenne), and mustard (Sinapsis alba).

The effect of eight polycyclic aromatic compounds (PACs) on the seed emergence and early life-stage growth of three terrestrial plants (Sinapsis alba, Trifolium pratense and Lolium perenne) were studied in a greenhouse, using a Danish agricultural soil with an organic carbon content of 1.6%. After three weeks of exposure, seed emergence and seedling weight (fresh weight and dry weight) were determined. Exposure concentrations were verified with chemical analysis. The substances tested were four polycyclic aromatic hydrocarbons (fluoranthene, pyrene, phenanthrene and fluorene), the N-, S-, and O-substituted analogues of fluorene (carbazole, dibenzothiophene and dibenzofuran, respectively), and the quinoline representative acridine. Seedling growth was a far more sensitive endpoint than seed emergence for all substances. Concentrations estimated to give a 20% reduction of seedling fresh weight (EC20-values) ranged from 36 to 290 mgkg(-1) for carbazole, 43 to 93 mgkg(-1) for dibenzofuran, 37 to 110 mgkg(-1) for dibenzothiophene, 140 to 650 mgkg(-1) for fluoranthene, 55 to 380 mgkg(-1) for fluorene, 37 to 300 mgkg(-1) for phenanthrene, and 49 to 1300 mgkg(-1) for pyrene. For acridine, no toxicity was observed within the concentration range tested (1-1000 mgkg(-1)). As illustrated by the EC20-values, there was a rather large difference in sensitivity between the species, and T. pratense was the most sensitive of the species tested.

Acridines↗
PubMed2004

Environmental characterization and radio-ecological impacts of non-nuclear industries on the Red Sea coast.

The Red Sea is a deep semi-enclosed and narrow basin connected to the Indian Ocean by a narrow sill in the south and to the Suez Canal in the north. Oil industries in the Gulf of Suez, phosphate ore mining activities in Safaga-Quseir region and intensified navigation activities are non-nuclear pollution sources that could have serious radiological impacts on the marine environment and the coastal ecosystems of the Red Sea. It is essential to establish the radiological base-line data, which does not exist yet, and to investigate the present radio-ecological impact of the non-nuclear industries to preserve and protect the coastal environment of the Red Sea. Some natural and man-made radionuclides have been measured in shore sediment samples collected from the Egyptian coast of the Red Sea. The specific activities of 226Ra and 210Pb (238U) series, 232Th series, 40K and 137Cs (Bq/kg dry weight) were measured using gamma ray spectrometers based on hyper-pure germanium detectors. The specific activities of 210Po (210Pb) and uranium isotopes (238U, 235U and 234U) (Bq/kg dry weight) were measured using alpha spectrometers based on surface barrier (PIPS) detectors after radiochemical separation. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in shore sediment and radium equivalent activity index (Bq/kg) were calculated. The specific activity ratios of 228Ra/226Ra, 210Pb/226Ra, 226Ra/238U and 234U/238U were calculated for evaluation of the geo-chemical behaviour of these radionuclides. The average specific activity of 226Ra (238U) series, 232Th series, 40K and 210Pb were 24.7, 31.4, 427.5 and 25.6 Bq/kg, respectively. The concentration of 137Cs in the sediment samples was less than the lower limit of detection. The Red Sea coast is an arid region with very low rainfall and the sediment is mainly composed of sand. The specific activity of 238U, 235U and 234U were 25.3, 2.9 and 25.0 Bq/kg. The average specific activity ratios of 226Ra/228Ra, 210Pb/226Ra and 234U/238U were 1.67, 1.22 and 1.0, respectively. The relationship between 226Ra/228Ra activity ratio and sample locations along the coastal shoreline indicates the increase of this ratio in the direction of the Shuqeir in the north and Safaga in the south where the oil exploration and phosphate mining activities are located. These activities may contribute a high flux of 226Ra. The concentration and distribution pattern of 226Ra in sediment can be used to trace the radiological impact of the non-nuclear industries on the Red Sea coast.

Egypt↗