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PubMed2005

[Study on the groundwater petroleum contaminant biodegradation by high efficient microorganism].

The groundwater petroleum contaminant biodegradation effect by high efficient hybrid microorganism was. investigated and the groundwater contaminant biodegradation transportation mathematical model was established in this study. The high efficient bacteria was separated and filtrated from the soil contaminated by petroleum hydrocarbon, and it was identified as Pseudomonas, Flavobacterium and Micrococcus. The petroleum degradation rates by these three kinds microorganism were 62%, 56% and 62% respectively in 24 h, and the high petroleum biodegradation rate 85% could be achieved by the hybrid microorganism constituted by these three kinds of microorganism, which was higher than that of any other each single bacteria community. The hybrid microorganism in-flowed into the reactor imitating the aquifer media with the petroleum wastewater, and it could form a steady microorganism zone in the foreside of the reactor. The petroleum biodegradation rate could achieve 60% when the petroleum wastewater flowed through this microorganism zone and the average petroleum biodegradation rate could reach up to 90% in the effluent. The groundwater contaminant biodegradation transportation mathematical model can predict the biodegradation of the wastewater through the microorganism zone effectively, of which the calculating values have good relativity with those of measurement.

Bacteria↗
PubMed1990

Helicobacter pylori-like microorganisms and chronic active gastritis in ferrets.

To determine the prevalence and histology of Helicobacter pylori (HP) associated gastritis in young ferrets, we examined 36 normal 2- to 4-month old ferrets. Identification of HP-like microorganisms included Warthin Starry stains of tissue sections, rapid urease test on fresh tissue, and culture. HP-like microorganisms were found in the stomachs of 35/36 ferrets. The highest density of microorganisms was seen in the antrum, where HP-like microorganisms were present in the pits and in deep glands. HP-like microorganisms were also seen in the cardia and on the foveolar epithelium of the fundus, but not in fundic glands. Chronic active gastritis was seen in all animals with HP-like microorganisms, but involved only the antrum. The distal antrum was most severely involved. One animal had no evidence of HP-like microorganisms on tissue sections or by rapid urease test. Gastric tissue sections from this animal showed only minimal infiltration of the lamina propria by polymorphonuclear leukocytes and lymphocytes. Gastritis associated with HP-like microorganisms is common in ferrets and is acquired at a young age. It is associated with chronic active antral gastritis similar to that seen in humans, suggesting that ferrets should provide a useful experimental model for HP-associated gastritis and peptic ulcer.

Animals↗
PubMed2002

Regrowth and survival of indicator microorganisms on the surfaces of household containers used for the storage of drinking water in rural communities of South Africa.

The present study covered two rural communities of South Africa: Ncera and Ntselamanzi villages. Raw water from Ncera river is used by the community of Ncera village for drinking, while the community of Ntselamanzi receives their drinking water from Alice purification system. Treated water is supplied to the community by a public standpipe system. In rural communities of South Africa, many households use polyethylene (PE) and galvanized steel (GS) containers for the storage of their drinking water. To investigate the regrowth and survival of indicator microorganisms on the surface of household containers during the storage of drinking water, PE and GS slides were suspended in the appropriate household containers for a period of 48 h. This period of 48 h was chosen as the study period because results from the questionnaire indicated that the largest percentage (62%) of households store their water for that length of time. The experiment was performed to test drinking water as it is collected and stored by rural communities. No disinfection of household containers or slides was done during the study period. Attached coliphages (F-RNA (FP) and somatic phage (SP), coliform bacteria (total coliform (TC), presumptive Escherichia coli (EC), Salmonella (Sal) and Clostridium perfringens (CP) were measured during the study period. With the exception of CP, attached indicator microorganisms consisted of TC, presumptive E. coli and Salmonella, somatic and F-RNA coliphages, although the yield (average count) for the last four groups (EC: < 1-3 cfu cm(-2), Sal: < 1-15 cfu cm(-2), FP: < 1-7 pfu cm(-2), SP: < 1-7pfu cm(-2)) was lower than that of TC (3-183 cfu cm(-2)). However, the lowest yield of indicator microorganisms was noted for presumptive E. coli. Whereas the occurrence and survival of TC was noted on the surface of household containers during the entire period of the experimental study, other indicator microorganisms occurred from time to time. The regrowth of indicator microorganisms occurred 48 h after the exposure of slides to both types of test waters. This length of time mostly resulted in the regrowth of TC (with an increase in bacterial counts) while the persistence of other indicator organism groups on the surface of the slides was apparent. A comparison between PE and GS containers showed that more TC (average count) regrew on PE than on GS containers (for river water, PE: from 36 to 55 cfu cm(-2), GS: from 25 to 26 cfu cm(-2); for standpipe water, PE: from 147 to 183 cfu cm(-2), GS from 3 to 4 cfu cm(-2)). This study revealed that both types of household containers supported the growth and survival of indicator microorganisms due to the bad quality of the intake water before storage. The storage of drinking water for 48 h mainly resulted in the regrowth of TC. Nevertheless, the persistence of other indicator microorganisms was observed on the surface of household containers.

Biofilms↗
PubMed2006

Growth inhibition by nitrocompounds of selected uric acid-utilizing microorganisms isolated from poultry manure.

The overall objective of this study was to evaluate the potential ability of nitrocompounds to reduce ammonia volatilization by inhibiting uric acid-utilizing microorganisms. Experiment I was conducted to evaluate the effects of nitrocompounds on the growth of uric acid-utilizing microorganisms isolated from poultry manure during six-hour incubation. There were five treatments: (1) control, (2) 50 mM nitroethane, (3) 50 mM nitroethanol, (4) 50 mM nitropropanol, and (5) 50 mM nitropropionic acid. Optical density values of nitrocompounds were significantly lower than that of control at two, four, and six hours. Plate counts of uric acid-utilizing microorganisms after six-hour incubation exhibited that nitrocompounds greatly reduced the growth of these microorganisms except for the nitroethane (P < 0.05). The nitropropanol and nitropropionic acid treatments showed significantly higher inhibitory effects compared to the nitroethanol. Experiments II and III were conducted to evaluate inhibitory effects of nitrocompounds on growth of uric acid-utilizing microorganisms compared to non-nitrocompounds such as ethanol, propanol, and propionic acid. Experiments II and III consisted of seven treatments: (1) control, (2) nitroethanol, (3) nitropropanol, (4) nitropropionic acid, (5) ethanol, (6) propanol, and (7) propionic acid. The incubation times of Experiments II and III were 6 and 24 h, respectively. The nitrocompounds were significantly more successful in inhibiting growth of uric acid-utilizing microorganisms compared to those non-nitrocompounds. These results suggest that nitrocompounds exhibit potential to reduce ammonia volatilization in poultry manure by inhibiting growth of uric acid-utilizing microorganisms.

Air Pollutants↗
PubMed2007

Fluorochrome and flow cytometry to monitor microorganisms in treated hospital wastewater.

Flow cytometry with a fluorescent technique (FCM/FL), epifluorescence microscopy with a fluorescent technique (EFM/FL), and a culture method were used and compared to study the microorganism population profiles in wastewater treatment. In the two non-culture methods (FCM/FL and EFM/FL), four fluorescent dyes [acridine orange (AO), 4',6-diamino-2-phenylindole dihydrochloride (DAPI), propidium iodide (PI), and YOPRO-1] were used to determine the total concentration and viability of microorganisms in the wastewater samples. Results showed that the total cell concentrations (both the bacteria and fungi) determined by using the non-culture-based methods were 18 to 67 times higher than those by the culture method (p = 0.036): the total cell concentration ranged from 1.10 x 10(7) to 2.44 x 10(8) cells/mL determined by both FCM and EFM with AO-staining method, and from 1.02 x 10(7) to 2.00 x 10(8) cells/mL by EFM with DAPI-staining method, whereas the culturable concentration of bacteria and fungi ranged from 0 to 3.22 x 10(6) CFU/mL and from 0 to 4.13 x 10(5) CFU/mL, respectively. No difference in total concentrations between dyes (AO and DAPI) and methods (FCM and EFM) were observed. By using EFM method, the microorganism viability ranged from 0.24 to 0.86 with PI staining and from 0.09 to 0.74 with YOPRO-1 staining. In the FCM analysis, the microorganism viability ranged from 0.23 to 0.87 with PI staining and from 0.18 to 0.73 with YOPRO-1 staining. In addition, the cultivability of microorganism ranged from 0 to 0.105 by the culture method. The total concentrations and viabilities of microorganisms were highly underestimated by the culture method. Results also showed that the viabilities determined by using either EFM/FL or FCM/FL were significantly higher than the cultivabilities. In addition, significant difference in viability between PI and YOPRO-1 for both EFM and FCM analysis was observed. However, the difference in viability between EFM and FCM depended on dyes. In regard to the difference between bacteria and fungi, significant difference in total concentration, viability, and cultivability was observed. In conclusion, the EFM/FL and FCM/FL methods can effectively assess total concentration and viability of microorganisms in environmental samples.

Colony Count, Microbial↗
PubMed2004

Assessment of electrical charge on airborne microorganisms by a new bioaerosol sampling method.

Bioaerosol sampling is necessary to monitor and control human exposure to harmful airborne microorganisms. An important parameter affecting the collection of airborne microorganisms is the electrical charge on the microorganisms. Using a new design of an electrostatic precipitator (ESP) for bioaerosol sampling, the polarity and relative strength of the electrical charges on airborne microorganisms were determined in several laboratory and field environments by measuring the overall physical collection efficiency and the biological collection efficiency at specific precipitation voltages and polarities. First, bacteria, fungal spores, and dust dispersed from soiled carpets were sampled in a walk-in test chamber. Second, a simulant of anthrax-causing Bacillus anthracis spores was dispersed and sampled in the same chamber. Third, bacteria were sampled in a small office while four adults were engaged in lively discussions. Fourth, bacteria and fungal spores released from hay and horse manure were sampled in a horse barn during cleanup operations. Fifth, bacteria in metalworking fluid droplets were sampled in a metalworking simulator. It was found that the new ESP differentiates between positively and negatively charged microorganisms, and that in most of the tested environments the airborne microorganisms had a net negative charge. This adds a signature to the sampled microorganisms that may assist in their identification or differentiation, for example, in an anti-bioterrorism network.

Aerosols↗
PubMed1992

Short-term effects of rhizosphere microorganisms on fe uptake from microbial siderophores by maize and oat.

Effects of rhizosphere microorganisms on Fe uptake by oat (Avena sativa) and maize (Zea mays) were studied in short-term (10 h) nutrient solution experiments. Fe was supplied either as microbial siderophores (pseudobactin [PSB] or ferrioxamine B [FOB]) or as phytosiderophores obtained as root exudates from barley (epi-3-hydroxy-mugineic acid [HMA]) under varied population densities of rhizosphere microorganisms (axenic, uninoculated, or inoculated with different microorganism cultures). When maize was grown under axenic conditions and supplied with FeHMA, Fe uptake rates were 100 to 300 times higher compared to those in plants supplied with Fe siderophores. Fe from both sources was taken up without the involvement of an extracellular reduction process. The supply of FeHMA enhanced both uptake rate and translocation rate to the shoot (more than 60% of the total uptake). However, increased density of microorganisms resulted in a decrease in Fe uptake rate (up to 65%), presumably due to microbial degradation of the FeHMA. In contrast, when FeFOB or FePSB was used as the Fe source, increased population density of microorganisms enhanced Fe uptake. The enhancement of Fe uptake resulted from the uptake of FeFOB and FePSB by microorganisms adhering to the rhizoplane or living in the free space of cortical cells. The microbial apoplastic Fe pool was not available for root to shoot transport or, thus, for utilization by the plants. These results, in addition to the low uptake rate under axenic conditions, are in contrast to earlier hypotheses suggesting the existence of a specific uptake system for Fe siderophores in higher plants. The bacterial siderophores PSB and FOB were inefficient as Fe sources for plants even when supplied by stem injection. It was concluded that microorganisms are involved in degradation processes of microbial siderophores, as well as in competition for Fe with higher plants.

Journal Article↗
PubMed1987

In vitro attachment of oral microorganisms to solid surfaces: evaluation of a controlled flow method.

A flow cell method was modified to provide shear-controlled experimental conditions for monitoring initial attachment and detachment of oral microorganisms to solid surfaces. Whole unstimulated human saliva was collected and circulated at a flow rate of 1 ml/min, through a cell composed of two parallel test plates. Infrared-transparent plates of medium surface energy served as test substrata in these initial calibration experiments. The plates presented a similar distribution of polar forces and dispersion forces at the surface as that of human tooth enamel and some restorative dental materials. Internal reflection infrared spectroscopy verified the presence of deposited organic material. After saliva had been circulated through the flow cells for 15 min at 37 degrees C, sterilized distilled water was introduced at the same flow rate and time of exposure to remove unattached microorganisms. Morphologic characterizations and counts of adherent Gram-stainable microorganisms were performed using incident light microscopy. Three different surface zones corresponding to the inlet area, the middle area and the outlet area of the flow cell were analyzed, and compared with enumerations of microorganisms in the whole saliva samples. Numbers of attached microorganisms in the three zones followed predictions from the laminar flow conditions, with a positive correlation shown between total numbers of microorganisms in saliva and total numbers of microorganisms attached. Cocci and rods were the only morphotypes observed on the plates, and no significant difference could be detected between the percentage of cocci and rods attached in the three different zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1994

[Development of detection system of extraterrestrial microorganisms].

A noble method for the exploration of terrestrial and extraterrestrial soil microorganisms, especially targeted for Mars, has been developed. The method is based on the microscopic observation using fluorescence techniques. Microorganisms could be fluorescent by adsorption, enzymatic cleavage of extrinsic fluorescence chromophores such as acridine orange, ANS and SFDA, and also by intrinsic chromophores. The characteristic points of our fluorescence method are shown below. 1. The present method detected all the culturable cells tested (about 200 species from bacteria to eukaryofic cells). 2. Microorganisms in soil were much brighter than background fluorescence of soil. Cell shapes and location were clearly observed. 3. An esterase substatum SFDA, discriminated vital (reproductive) cells from dead. On the other hand, a membrane probe, ANS, detected both vital and dead cells. 3. Pre-treatment of cells with bleaching reagents improved the detection efficiency. Especially, this pretreatment was effecfive in Fungi with black chromophores. 4. Some anaerobic microorganisms such as methanogenic bacteria with intrinsic chromophores can be detected without stain. 5. Application of the technique to terrestrial soil revealed that more than 100 times larger cell density was obtained compared to the value obtained by the classic plate counting technique. Vertical distribution of microorganism of soil microorganisms from Mt. Shigayama showed that, at surface, cell density was small and maximum was shown below 15 cm from surface. 6. Some pre-biotic cell (cell like aggregates composed of amino acids) could be detected by SFDA or ANS. It can be concluded that the fluorescence technique is one of the most promising method for the exploration of extraterrestrial microorganisms.

Extraterrestrial Environment↗
PubMed1990

Quantity and characteristics of microorganisms associated with ruminal fluid or particles.

An experiment was conducted to 1) determine quantity of microbial CP and DM associated with undigested feed particles, 2) quantify the amount of microorganisms removed from ruminally incubated forages and 3) compare forage disappearances (D) corrected for microbial contamination, using diaminopimelic acid (DAPA) ratios obtained from particle-associated or fluid-associated microorganisms. Samples of alfalfa hay, bermudagrass hay and orchardgrass hay placed in dacron bags were incubated via ruminal cannula for 6 and 12 h. Whole ruminal contents (WRC) were sampled at the time of bag removal and partitioned into fluid- and particle-associated microorganisms. Particle-associated microorganisms were further divided into loosely-associated (LA) and firmly associated (FA) microorganisms. Percentage microbial CP and DAPA, quantities of OM, CP (mg) and DAPA (micrograms), microbial contamination and microbial contribution to ruminal contents were not affected by time (P greater than .05). The highest concentrations of CP and DAPA were found in fluid and LA, respectively (P less than .01). The total amount (content) of OM, CP and DAPA were highest in FA and lowest in microbes in the fluid fraction. Firmly-associated microorganisms constituted 54.1% of the particle-associated population. Corrected DMD were higher (P less than .01) based on FA than on fluid and LA microbe compositions. Corrected CPD were similar (P greater than .10) between populations except at 6 h, when LA corrected CPD were lower. Theoretically, using FA microorganisms should give the most accurate correction for microbial contamination. However, results indicate that, although the three populations differed in composition, fluid and FA corrected CPD were similar. Corrections based on composition of any of these three populations will yield higher estimates of disappearance compared with uncorrected values.

Animal Feed↗
PubMed2006

Characterization of a novel C-type lectin, Bombyx mori multibinding protein, from the B. mori hemolymph: mechanism of wide-range microorganism recognition and role in immunity.

To investigate the system used by insects to recognize invading microorganisms, we examined proteins from the larval hemolymph of Bombyx mori that bind to the cell surface of microorganisms. Two hemolymph proteins that bound to the cell surfaces of Micrococcus luteus and Saccharomyces cerevisiae were shown to be identical. This protein bound to all 11 microorganisms examined-5 Gram-negative bacteria, 3 Gram-positive bacteria, and 3 yeasts-and was consequently designated B. mori multibinding protein (BmMBP). The sequence of the cDNA encoding BmMBP revealed that it was a C-type lectin with two dissimilar carbohydrate-recognition domains (CRD1 and CRD2) distantly related to known insect C-type lectins. CRD1 and CRD2 were prepared as recombinant proteins and their binding properties were investigated using inhibition assays. Each domain had wide, dissimilar binding spectra to sugars. These properties enable BmMBP to bind to two sites on a microorganism, facilitating high-affinity binding to many types of microorganisms. The dissociation constants of BmMBP with M. luteus cells and S. cerevisiae were 1.23 x 10(-8) and 1.00 x 10(-11) M, respectively. rBmMBP triggered the aggregation of hemocytes from B. mori larvae in vitro and microorganisms recognized by BmMBP were surrounded by aggregated hemocytes in vivo, forming a nodule, which is the typical cellular reaction in insect immune responses. These observations suggest that BmMBP functions as a trigger for the nodule reaction and that the multirecognition characteristic of BmMBP plays an important role in the early stages of infection by a variety of microorganisms.

Amino Acid Sequence↗
PubMed2006

Sterilization efficiency of the photocatalyst against environmental microorganisms in a health care facility.

The photocatalyst equipment consists of a titanium dioxide membrane and an ultraviolet lamp. The authors studied if the photocatalyst equipment is practically useful in sterilizing environmental microorganisms in the health care facility. The number of microorganisms was compared in the cases of no sterilization (control) and the photocatalyst sterilization. As a result, a statistical difference was observed between control and the photocatalyst sterilization against airborne microorganisms (p < 0.01), but not against surface microorganisms (p > 0.2). The photocatalyst uses an air sucking system, so it may be ineffective against microorganisms tightly attached to surfaces. However, the effectiveness of the photocatalyst to sterilize airborne microorganisms in the health care facility was successfully confirmed. Concerning the humidity effect on the photocatalyst sterilization, the authors compared the number of airborne microorganisms in cases of the control, UV alone and photocatalyst sterilization when humidity was changed. A statistical difference was observed between UV and the photocatalyst sterilization (p < 0.01) when humidity was increased to 60-70%, but not observed between UV and the photocatalyst sterilization (p > 0.2) when humidity was not controlled and was around 10-20%. This indicates that maintaining high humidity levels will present satisfactory sterilization results due to a greater production of OH radicals. From data obtained, no effect of the adsorption on the TiO2 membrane could be observed.

Adsorption↗
PubMed2006

Importance of considering injured microorganisms in sterilization validation.

Disinfection or sterilization treatment by heating, irradiation, or chemicals can cause injury to microorganisms at sublethal levels. Microbial injury is the inability to grow under conditions suitable for the uninjured microorganisms. This inability of injured microorganisms to grow is explained in terms of more complex or different nutritional requirements or in terms of increased sensitivity to environmental conditions such as incubation conditions (time or temperature) or to chemical agents such as halogen compounds. Injured microorganisms can be distinguished from those that are dead or mutated by their ability to regain normal physiological activity when placed in appropriate conditions for cultivation. The return to normal physiological function has been termed repair. The extent and severity of sublethal injury, the mechanisms of injury, and the mechanisms and degree of recovery vary with the sterilization procedures, the species, the strains, the condition of the microorganism, and the methods of repair. Injury to spore formers has been detected at different stages of the spore cycle. The sites of injury include damage to enzymes, membrane disruption, and/or damage to DNA or RNA. Information on the sublethal injury and recovery of microorganisms is very important in evaluating sterilization/disinfection procedures. This paper supplies academic as well as practical information dealing with the repair, and detection of injured microorganisms for performing reproducible sterilization validation.

Bacteria↗
PubMed2000

Microorganisms resistant to heavy metals and toxic chemicals as indicators of environmental pollution and their use in bioremediation.

Microorganisms present in water samples from various industrial effluents were analysed for their resistance to lead, chromium, and cadmium. The ability of these microorganisms to grow on or metabolize toxic hydrocarbons and pesticides was also checked. Microorganisms in samples from the steel and tanning industries were generally resistant to metal ions but were not capable of metabolizing toxic hydrocarbons. Conversely, microorganisms found in samples of pesticide and from the chemical industry were capable of metabolizing hydrocarbons and pesticides but were not much resistant to metal ions. Microorganisms from effluents of the paint industry and urban wastes were resistant to lead. A correlation between the population of microorganisms and the type of pollution was observed. Indigenous microorganism could be regarded as indicators of pollution and be used in various operations to resist, process, metabolize, and detoxify toxic industrial wastes.

Bacteria↗
PubMed2004

[Microorganism contamination in in vitro fertilization-embryo transfer system and their sources].

OBJECTIVE: To investigate the incidence of microorganism contamination in in vitro fertilization-embryo transfer (IVF-ET) and to determine the sources of microorganism. METHODS: Two thousand one hundred and seventy-four cycles of in vitro fertilization from January 1999 to June 2003 were evaluated retrospectively and bacterial cultures were performed in 61 semen samples from asymptomatic men with normal semen parameters and in 34 follicle fluid samples from infertility women through oocyte picking up procedures. RESULTS: Microorganisms were found in 11 cases. The incidence of their contamination in IVF culture system was 0.51% and the most common microorganisms were Escherichia coli and fungi. Microorganisms were detected in 97% of unprocessed semen, 10% in processed semen, 6% in semen mixed with media and 9% in follicle fluid. CONCLUSIONS: The incidence of microorganism contamination was 0.51% and the most common microorganisms were Escherichia coli and fungi. Semen may have the potential to contaminate IVF culture system.

Embryo Transfer↗
PubMed1997

Microorganisms and their interaction with the immune system.

Microorganisms interact with the immune system in multiple ways. In an interaction between a microorganism and its host, the defense of the host does not go unchallenged. Microorganisms have for decades been suspected of possessing the capabilities of hiding from and escaping the consequences of immune surveillance. Escape mechanisms like antigenic variation, latency, and genomic integration can best be described as passive mechanisms for avoiding interaction with the host immune system, to differentiate them from the more engaging and host-directed active mechanisms of interaction. Studies of the mechanism of direct entry of viruses (HIV, measles, and enteroviruses), bacteria (streptococci and staphylococci), and parasites (Leishmania and plasmodium) into immune cells like CD4+ T cells or macrophages, as reported very recently, indicate an even more aggressive mode of interaction. This aggressive mechanism of interaction with the components of the host immune system allows the microbe not only to block the normal function of immune components on the surface of immune cells from functioning, but also to obliterate a vital immune function, cellular immunity, causing immunosuppression, e.g. the depletion of CD4+ T cells due to the entry and replication of HIV. Collectively, microorganisms have evolved various mechanisms by which they can actively block almost any cellular, humoral, or systemic immune response. One general feature of the proteins that assist microorganism to immunomodulate and actively evade host defense is their structural and therefore functional similarity to the host proteins, which they effectively mimic. Understanding the different mechanisms by which microorganisms interact with the immune system can impact the design of live vaccines as well as the development of novel therapeutic immunomodulators that can provide medicine with powerful new tools to manage immune disorders, allograft rejection, remote multiple organ failure resulting from trauma, autoimmune diseases, etc.

Animals↗
PubMed2002

Rapid microorganism identification with on-slide proteolytic digestion followed by matrix-assisted laser desorption/ionization tandem mass spectrometry and database searching.

A simple method for microorganism identification is proposed in this paper. In this method, no isolation or fractionation of microorganisms and no special search algorithm or database are needed. Experimentally, a sample of the unfractionated intact microorganism is subjected to brief on-slide proteolytic digestion and the digestion product ions detected in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) are selected for tandem mass spectrometry (MS/MS). Database searching using the MS/MS spectrum identifies the microorganism protein, and thereby, according to the source of the protein, the microorganism. The method was demonstrated to be feasible with enterobacteriophage MS2 as the model microorganism. The novel method is simple, rapid, and requires a small quantity of sample.

Amino Acid Sequence↗
PubMed1996

Complete degradation of xenobiotic surfactants by consortia of aerobic microorganisms.

Linear alkylbenzene sulphonates are primarily attacked via a hydroxylation of the alkyl chain from the methyl group followed by beta-oxidation. The alkyl chain is metabolized by pure cultures to give sulphophenyl carboxylates which accumulate in the medium. In mixed culture, other microorganisms are capable of degrading sulphophenyl carboxylates. Formation of ethylene glycol monosulphates as major products of alkyl ethoxy sulphates demonstrates that the ether bonds are cleaved. The bacteria involved in growing on the alkyl chain are unable to utilize the hydrophilic moiety. This hydrophilic moiety, in turn, is degraded by other microorganisms. The degradation of alkylphenol ethoxylates and highly branched alcohol ethoxylates proceeds by shortening the polyoxyethylene chain leaving the hydrophobic part of the molecule. The biodegradation of linear alcohol ethoxylates and ethoxylated fatty amines is initiated by a central cleavage or omega-oxidation. Subsequent oxidation of the alkyl chains results in the production of polyethylene glycols and secondary ethoxylated amines. Both polar moieties are metabolized by other microorganisms. Degradation of alkyltrimethylammonium salts and alkylamines is initiated by a cleavage of the Calkyl-N bond. The central fission leads to the formation of alkanals which are readily converted by beta-oxidation. The alkyl chain-utilizing bacteria are not able to degrade the methylamines. The methylamines, in turn, are subject to biodegradation by methylotrophs. The limited metabolic capacities of pure cultures of microorganisms utilizing surfactants point to the requirement of consortia to degrade surfactants completely. Complete degradation of surfactants is accomplished by mixed cultures of microorganisms constructed on the basis of synergistic and commensalistic relationships. However, degradation of a surfactant by one member of a commensalistic consortium may lead to the production of toxic or non-toxic metabolites. Waste water treatment without the build up of such metabolites can be achieved in plants operated with sludge retention times that are suitable for maintaining all microorganisms of the consortium. In contrast, in natural ecosystems the introduction of a surfactant may result in a transient formation of a metabolite.

Aerobiosis↗