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Effects of chlorinated hydrocarbons on the heterotrophic activity of aquatic microorganismsBoyd, Walter Sean January 1978 (has links)
This study investigated the short-term inhibitory effects of 8 chlorinated compounds on aquatic microorganism heterotrophic activity. A technique involving the measurement of substrate uptake rates using radio-actively labeled glucose was employed. All compounds studied have been identified as foreign pollutants in aquatic environments and include the highly toxic ones DDT, dieldrin and a PCB (Aroclor 1254). The aquatic microorganisms were predominatly bacteria.
On a short-term basis, the PCB and tetrachlorophenol were the most toxic pollutants, decreasing the maximum glucose uptake rate (Vmax) by 50 percent at 250 ppb concentrations. The remaining pollutants had little effect under 2500 ppb. In addition, tetrachlorophenol was the only compound to significantly increase glucose turnover time (Tt).
Results from other experiments were: the toxicity of tetrachlorophenol varied according to the (environmental) water temperature; tetrachlorophenol affected the uptake of glucose more than that of two amino acids, alanine and glutamic acid; with respect to di-, tri-, and tetrachlorophenol, neither the chlorine percentage per pollutant molecule, nor the number of pollutant molecules per mole of water, varied linearly with the pollutant's ability to inhibit glucose uptake; the combined toxicities of various pollutants reduced uptake to only 9 percent below the average of their separate effects; and none of the 4 pollutants tested for long-term effects (DDT, PCB, dieldrin and tetrachorophenol) inhibited uptake after 4 days.
It was concluded that the two tests (Type I and Type II as described in Section 2) were quick and reliable techniques for assessing the short and long-term effects of a concentration of a pollutant on heterotrophic activity. It was also determined that other pollutants should be tested for their long-term effects under a variety of conditions (for example, their effects on different substrates and on the sediment microbial community). / Science, Faculty of / Zoology, Department of / Graduate
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Microbial interactions in drinking water systemsKhan, Wesaal 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Microorganisms show a tendency to accumulate on surfaces in aqueous environments
to form biofilms. Microbial biofilms represent a significant problem in public health
microbiology as the development of these microbial communities, especially in water
distribution systems, may lead to (i) the enhanced growth of opportunistic pathogens,
(ii) the development of organoleptic problems, (iii) the reduction in the flow rate and
(iv) the regrowth of microorganisms.
In this project, biofilm monitors were installed in a large water distribution
system to study biofilm phenomena in drinking water systems, and to deduce the
biological stability and quality of the potable water. Measurements of biofilm formation
potential showed that biofilms did not reach a steady state after 100 to 150 days. The
microbial cells in these biofilms were mostly non-culturable. The contribution of the
heterotrophic colony count to active biomass, as determined with cell numbers based
on ATP measurements were often < 1%, while the ratio of heterotrophic plate counts
and direct acridine orange counts were also <1%. The ratio between cell numbers
based on ATP measurements and direct acridine orange counts were often < 100%.
Results also showed that under certain conditions, such as those investigated in the
present study, 1 pg of ATP may not be equal to approximately 104 active
bacteria/cells, as stipulated by previous investigations, and that the average ATP
content per active bacterial cell is indeed less than 10-16 - 10-15 g. It was calculated
that threshold values for assimilable, and dissolved organic carbon below -5 IJg Gil
and -0.5 mg Gil, respectively, should be target values for the control of biofilm
formation in this system. It was shown that polyethylene, polyvinylchloride, teflon,
plexiglass, copper, zinc-coated steel and aluminium provide favourable attachment
surfaces that allowed primary colonisation and subsequent biofilm formation.
Significant (p < 0.05) differences in surface colonisation on the materials were
observed, indicating that the composition of the material has a direct influence on
microbial colonisation. The two grades of stainless steel evaluated in this study were
the least favourable materials for biofilm formation. It was further demonstrated that
the nature of the surface of these materials, flow conditions and water type all had a
direct influence on biofilm formation. While modification of the attachment surface did
not result in significant differences (p > 0.05) in disinfection efficiency of two commonly
used biocides, the concentration of the biocide, as well as the material to which the
biofilm is attached, greatly influenced biocidal efficiency. The results show that biofilm
monitoring needs to be implemented at the water treatment plants in addition to
common biostability measurements. / AFRIKAANSE OPSOMMING: Mikro-organismes neig om te akkumuleer aan oppervlaktes in akwatiese omgewings
om biofilms te vorm. Mikrobiese biofilms verteenwoordig In betekenisvolle probleem
in publieke gesondheidsmikrobiologie omdat die ontwikkeling van hierdie mikrobiese
gemeenskappe in waterverspreidingsisteme mag lei tot (i) die verhoogde groei van
opportunistiese patogene, (ii) ontwikkeling van organoleptiese probleme, (iii) die
vermindering in die vloeitempo en (iv) die hergroei van mikro-organismes.
In hierdie projek was biofilm monitors geïnstalleer in In groot
waterverspreidingsisteem om biofilm fenomene in drinkwatersisteme to bestudeer, en
om die biologiese stabiliteit en kwaliteit van drinkwater af te lei. Bepalings van
biofilmvormingspotensiaal het aangetoon dat biofilms nie In stabiele stadium na 100
tot 150 dae bereik nie. Die mikrobiese selle in hierdie biofilms was meestal niekweekbaar.
Die bydrae van die heterotrofiese kolonie tellings tot aktiewe biomassa,
soos bepaal deur seltellings gebaseer op ATP metings was dikwels < 1%, terwyl die
verhouding van die heterotrofiese plaatteIIings en direkte akridien oranje tellings ook
< 1% was. Die verhouding tussen seltellings, gebaseer op ATP metings en direkte
akridien oranje tellings was dikwels < 100%. Resultate het ook aangetoon dat onder
sekere omstandighede, soos dié wat ondersoek was in die huidige studie, 1 pg ATP
nie gelyk is aan min of meer 104 aktiewe bakterieë/selle soos gestipuleer deur vorige
ondersoeke nie, en dat die gemiddelde ATP inhoud per aktiewe bakteriële sel
inderdaad minder as 10-16 tot 10-15 g is. Dit was bereken dat die drempelwaardes vir
assimileerbare en opgeloste organiese koolstof onder -51-1g C/l en -0.5 mg C/l,
onderskeidelik, teikens moet wees vir die beheer van biofilmvorming in hierdie
sisteem. Dit was aangetoon dat polyetileen, polyvinielchlroried, teflon, plexiglas,
koper, sink-bedekte staal en aluminium gunstige aanhegtings oppervlaktes voorsien
wat primêre kolonisering en daaropvolgende biofilmvorming toelaat. Betekinisvolle (p
<0.05) verskille in oppervlak kolinisering op die materiale was waargeneem, wat
aandui dat die samestelling van die materiaal In direkte invloed op mikrobiese
kolonisering het. Die twee tipes vlekvryestaal wat geëvalueer was in hierdie studie,
was die minder gunstige materiale vir biofilmvorming. Dit was verder gedemonstreer
dat die aard van die oppervlak van hierdie materiale, vloeitoestande, en water tipe
almal In direkte invloed het op biofilmvorming. Terwyl die aanpassing van
aanhegtingsoppervlak nie die ontsrnettinqsdoeltreffendheid resultaat van die twee
algemeen-gebruikte biosiede betekinisvol (p > 0.05) beïnvloed het nie, het die
konsentrasie van die biosiede
doeltreffendheid grootliks beïnvloed.
asook die aanhegtings-materiaal, biosied
Die resultate het aangetoon dat biofilm
monitering geïmplementeer moet word by waterbehandelingsaanlegte as In alternatief
vir algemene biostabiliteit metings.
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Virus removal during conventional drinking water treatmentRose, Joan Bray. January 1985 (has links)
The isolation of viruses from treated drinking water has raised concerns that water treatment methods may not always adequately insure the removal of viruses from water designated for human consumption. The isolation of enteroviruses and rotavIruses from treated drinking water in a distribution system and at a water treatment plant has been previously reported. Isolation of viruses from drinking water that met recommended levels of coliform bacteria, chlorine and turbidity. The question is raised as to whether or not current drinking water standards ensure safe drinking water. The isolation of enteroviruses and rotaviruses from treated drinking water In a distribution system and at a water treatment plant. This study reports the results of a more extensive investigation on the removal of naturally occurring viruses by water treatment processes including prechlorination/clarification, filtration, and chlorination at a fullscale water treatment plant. The removal of enteroviruses and rotaviruses was studied at a full scale 205 mgd water treatment plant involving chemical clarification, sand filtration and chlorination. Enteric viruses, as well as coliphages, indicator bacteria, physical and chemical variables were measured in water samples taken at each stage of the drinking water treatment facility. Linear intercorrel ations were analyzed for all the variables. The numbers of standard plate count bacteria and coliphage were positively correlated to the presence of enteroviruses in the raw water while coliphage counts were positively correlated to the presence of rotaviruses in the finished water. Samples were taken during the dry and rainy seasons. During the dry season, it was found that reduction of enteroviruses and rotaviruses averaged 81% and 93%, respectively, for the complete treatment process and were the least efficiently removed as compared to the other microorganisms. The greatest reduction of enterovIruses occurred during pre-chlorination/flocculation and filtration, while a significant reduction of rotav I ru ses occurred during prechlorination/ flocculation and final chlorination. Enteroviruses or rotaviruses occurred in 24% of the finished water samples containing chlorine levels of >0.2 mg/L, and meeting coliform bacteria (1/100 ml) and turbidity (1 NTU) standards. During the rainy season removals were found to be far less efficient for all the variables and rotaviruses were isolated from all finished water samples. The results of this study indicate that finished water having measurable levels of free residual chlorine and meeting standards for col iform bacteria, and turbidity cannot be assumed to be virus free.
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The development of a dot blot assay using gene probes for the detection of enteroviruses in waterMargolin, Aaron B.,1958- January 1986 (has links)
Enteric viruses are viruses which replicate in the intestinal tract of man and animals. One mode of transmission for enteric viruses is the fecal-oral route. Drinking water which has been contaminated with sewage or sewage effluent has been implicated as a means for the spread of enteric viruses. Monitoring water for virus contamination requires two steps: 1) the collection and the concentration of the water sample and 2) the isolation and identification of the virus present. Current methods for the detection of enteric viruses in water requires the use of animal cell culture. This technique has several drawbacks, such as: 1) long incubation periods, up to two and three weeks, before some enteric viruses are detected, 2) not all viruses can be detected in one cell line, and 3) not all viruses have been grown in cell culture. More rapid techniques, such as fluorescent antibody or radioimmunoassay do not have the needed sensitivity to detect the low levels of virus found in contaminated water. These techniques also require the production of an antibody for each different virus type. An alternative technique for the detection of viruses in water was sought. Recent advances in recombinant DNA technology now makes it possible to detect viruses without the use of cell culture or antibodies. Gene probes that hybridize to the RNA of poliovirus and hepatitis A virus were tested for their ability to detect different enteric viruses. The probes were labeled with ³²P dCTP and ³²P dATP to a specific activity greater then 1.0 x 10⁹ cpm/ug DNA. Gene Screen Plus (NEN) was chosen as the hybridization membrane since it was more sensitive to virus detection than the other membranes tested. A dot-blot apparatus (Bio Rad) was used to apply the samples. Results were visualized by autoradiography for thirty-six hours at -70° C. One infectious unit of poliovirus and hepatitis A virus was detected using labeled cDNA probes. Upon comparison, the dot blot assay was as sensitive as tissue culture for the detection of poliovirus in beef extract, secondary effluent, and tapwater. Environmental samples, such as secondary effluent, reclaimed wastewater and unchlorinated drinking water were also assayed for poliovirus and hepatitis A virus with the use of gene probes. The results presented here offer an alternative method for screening water samples for the presence of enteric viruses.
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Immunoassay test strip for Microcystin-LR detectionUnknown Date (has links)
Microcystin-LR (MCLR) is hepatotoxic to animals and humans with disruption of liver structure causing cytoskeletal damage, necrosis and pooling of blood in the liver, leading to large increase in liver weight. It is also a strong liver tumor promoter and protein phosphatase inhibitor. Microcysin-LR binds protein phosphatases 1 and 2A, and influences regulation of cellular protein phosphorylation. In the present study, a colloidal gold based immunoassay test strip was developed for Microcystin-LR detection. The detection limit was found to be 1 ng/mL. 5 nm colloidal gold test strips exhibits more efficient for detection, compared with 20 nm colloidal gold test strips. The interaction between Microcystin-LR antibody (immunoglobulin G) and colloidal gold nanoparticles was investigated by various analytical methods, including Ultraviolet/Visible (UV/VIS), Fourier Transform Infrared (FTIR) and Fluorescence spectroscopy as well as transmission electron microscopy (TEM). / by Jiesi Xu. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
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Qualidade da água tratada para hemodiálise e intercorrências clínicas apresentadas pelos pacientes em tratamento: enfoque para metais e agentes microbiológicos / Quality of treated water for hemodialysis and clinical intercurrences presented by patients in treatment: a focus on metals and microbiological agentsSuzuki, Meire Nikaido 28 November 2016 (has links)
A contaminação por metais e agentes microbiológicos na água de hemodiálise pode ocasionar manifestações clínicas nos pacientes em tratamento, como anemia, dor óssea, picos hipertensivos, distúrbios neurológicos, episódios de hipotensão, náuseas e vômitos. Avaliar e garantir níveis mínimos de contaminação por metais e micro-organismos na água de hemodiálise pode, assim, aumentar a segurança do paciente. O objetivo deste estudo foi avaliar a relação entre a qualidade da água tratada para hemodiálise e as intercorrências clínicas apresentadas pelos pacientes. Foi utilizado um questionário para a coleta de informações referentes aos aspectos demográficos e hábitos de consumo, e um instrumento de registro mensal de intercorrências clínicas e parâmetros clínico-laboratoriais; tais informações foram obtidas por meio de entrevista e no prontuário do paciente, respectivamente. As dosagens de metais em sangue foram realizadas por EAA (Chama/ Forno de Grafite) no Setor de Metais do HCFMRP/USP, e em água por ICP/MS no Laboratório de Toxicologia e Saúde Ambiental da Universidade Rovira i Virgili, Espanha. A quantificação de bactérias heterotróficas foi realizada pelo Método \"Pour Plate\", a de Coliformes totais e E. coli por Tubos Múltiplos e a detecção de fungos filamentosos por Membrana Filtrante no Laboratório de Ecotoxicologia e Parasitologia Ambiental da EERP/USP. A quantificação de endotoxina foi realizada pela técnica cromogênica do lisado de Limulus Amebocyte, no Laboratório de Vacinas Gênicas da FMRP/USP. Para a análise dos dados foi aplicado o teste Wilcoxon- Mann Whitney bilateral ou Teste t bilateral no software R®, o teste de Kruskal-Wallis no software GraphPad Prism 6®, e ajustados modelos de regressão no software SAS/STAT®. Verificou-se que a concentração de Pb sérico entre os pacientes que exercem/exerciam atividades relacionadas à maior exposição a metais foi significativamente maior (p-valor = 0,0208) que aqueles que nunca realizaram tais atividades. A concentração média de Cu, Pb e Zn na água após filtração por osmose reversa (AFOR) foi inferior ao preconizado na RDC nº 154/2004 e RDC nº 11/2014 da ANVISA, somente o Al (15,35 ± 14,53 µg/L) apresentou concentração média superior a tais normativas. Não foi detectado presença, durante todo o período do estudo, de Cd, coliformes totais, E. coli e endotoxina na água AFOR. A contagem de bactérias heterotróficas foi significativamente maior (p-valor <0,0001) na água após a pré- filtração (APF) do que na água potável (AP) e na água AFOR. As concentrações de cloro total e nitrato foram significativamente maiores (p-valor <0,0001) na AP em relação à água APF e na água AFOR. A contagem de bactérias heterotróficas e a concentração de nitrato na água AFOR foi inferior ao preconizado nas normativas, o cloro total apresentou concentração média superior ao estabelecido na RDC nº 11/2014, mas dentro do limite preconizado pela RDC nº 154/2004. Foi verificado presença de fungos filamentosos em todos os pontos de coleta. Constatou-se que a diminuição da concentração de Cu e nitrato em água de hemodiálise foram significativos (p-valor = 0,001 e 0,0354, respectivamente) para explicar o aumento da concentração de hemoglobina em sangue. Embora a água utilizada no preparo do dialisato tenha apresentado excelente qualidade microbiológica e físico-química é importante o monitoramento contínuo para garantia dos parâmetros de qualidade e prevenção de intercorrências clínicas / The contamination by metals and microbiological agents in hemodialysis water can cause clinical manifestations in hemodialysis patients, such as anemia, bone pain, hypertensive peaks, neurological disturbances, hypotension episodes, nausea and vomiting. Evaluating and assuring minimum levels of contamination by metals and microorganisms in hemodialysis water can improve patient safety. The aim of the study was assess the relationship between the quality of treated water for hemodialysis and the clinical intercurrences presented by patients. A questionnaire was used to collect information about demographic characteristics and consumer habits, and an instrument was applied for monthly recording of clinical intercurrences and clinical laboratorial parameters. The data were obtained by interviews and from clinical records, respectively. Concentrations of metals in blood were determined by AAS (flame/graphite furnace) in the Metals Sector of HCFMRP/USP, and in water by ICP/MS in the Laboratory of Toxicology and Environmental Health of University Rovira i Virgili, Spain. The quantification of heterotrophic bacteria was performed by the pour plate method, the total coliforms and E. coli by multiple tubes, and filamentous fungi by the membrane filter at the Laboratory of Ecotoxicology and Environmental Parasitology of the EERP/USP. The quantification of endotoxin was performed by the chromogenic technique of Limulus Amebocyte lysate, at the Gene Vaccine Laboratory of the FMRP/USP. For data analysis, the bilateral Wilcoxon-Mann-Whitney or bilateral t-test was applied using the R® software, the Kruskal-Wallis test using GraphPad Prism 6®, and adjusted regression models with SAS/STAT®. The results showed that patients who reported having or having had job activities with high exposure to metals showed serum concentrations of Pb significantly higher (p-value = 0.0208) than patients without job exposure to metals. The mean concentrations of Cu, Pb and Zn in the water after reverse osmosis (ARO) were below the threshold limits set by RDC nº 154/2004 and RDC nº 11/2014 from the ANVISA; only Al (15.35 ± 14.53 µg/L) was present in average concentration higher than resolutions. The presence of Cd, total coliforms, E. coli and endotoxins in the water ARO during the study was not detected. The counting of heterotrophic bacteria was significantly higher (p-value <0.0001) in the water after the pre-filtration (APF) than the potable water (PW) and the wate ARO. The concentrations of total chlorine and nitrate were significantly higher (p-value <0.0001) in the PW than the water APF and the water ARO. The counting of heterotrophic bacteria and concentration of nitrate in the water ARO were below the reference limits, while the total chlorine was present in higher concentration than the established in RDC nº 11/2014 but lower than that in RDC nº 154/2004. Filamentous fungi were detected at all sampling points. The decrease in the levels of Cu and nitrate in hemodialysis water were significant (p value = 0.001 and 0.0354, respectively) to explaining the increase of hemoglobin concentration in the blood samples. Although the water used for dialysis showed excellen microbiological and physicochemical quality, it is important to monitor it regularly to assure the quality parameters and prevent clinical intercurrences
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Microbial pollutants in stagnant water in RR section, Khayelitsha, Western Cape, South AfricaLeuta, Qenehelo Alice January 2015 (has links)
Dissertation submitted in partial fulfilment of the requirements for the degree Master of Technology: Environmental Management in the Faculty of Applied Science at the Cape Peninsula University of Technology / Greywater is domestic wastewater from daily kitchen, laundry, bath, shower, hand washing practices and does not include wastewater from the toilet. Greywater from informal settlement has been identified as important environmental pollution sources. Inadequate sanitation and poor drainage in informal settlements result in greywater being stagnant at the base of communal taps. This water has a potential to cause health problems to those who come in contact with it. Studies of greywater quality in informal settlements in South Africa tend to concentrate on physico-chemical analysis and microbial indicator organisms. In order to adequately manage greywater in informal settlements there is a need to understand the microbial pathogens present in such water. Therefore this study is aimed at determining the level of microbial contamination of stagnant greywater in the RR Section of Khayelitsha, Western Cape. Six sampling sites were identified and sampling of stagnant greywater was conducted twice a month (from January to May 2013) from the base of six communal taps, which served as the sampling sites.
The microbial enumeration techniques employed in this study were the Most Probable Number (MPN) techniques, the Heterotrophic Plate Count (HPC) technique and the
Flow Cytometric (FCM) technique. The API 20E and the RapID™ ONE systems were used to identify possible pathogenic Gram-negative microorganisms, while possible pathogenic Gram-positive microorganisms were identified with the BBL Crystal™ Gram Positive (GP) Identification (ID) system. The highest MPN counts were 1.6 x 108 microorganisms/100mℓ recorded at Site A (weeks 3 and 5) as well as at Site B (week 5). The corresponding highest faecal coliform count was 4.7 x 106 microorganisms/100mℓ obtained at Site B (week 5). The highest E. coli count observed was 1.8 x 106 microorganisms/100mℓ recorded at Site A (week 5) and Site F (week 5). In comparison, the highest HPC count was 2.9 x105 microorganisms/mℓ recorded at Site C in week 4. The results obtained by the MPN and HPC techniques were significantly (p < 0.05) higher than the water quality standards by Department of Water Affairs and Forestry (DWAF) (1996a; 1996b) and the SABS (2011). The highest total FCM and viable FCM counts were 3.4 x 107 microorganisms/mℓ and 3.1 x 107 microorganisms/mℓ, respectively recorded at Site A in week 5. The FCM technique displayed significantly (p < 0.05) higher results than both the MPN and HPC techniques, which highlighted its reliability in obtaining more accurate enumeration results.
The RapID™ ONE and the API 20E identification systems mostly identified Escherichia coli, Klebsiella pneumonia, K. oxytoca, Acinetobacter baumannii/calcoaceticus and Enterobacter cloacae, while the organisms more commonly identified by the BBL
Crystal™ Gram Positive (GP) Identification (ID) system, were the Corynebacterium species, and Bacillus cereus. The presence of these organisms raises health concern to the community of RR Section, as some are known to cause waterborne diseases, while others are known to cause nosocomial infections.
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Detection of Giardia cysts by cDNA probe and application to water samplesAbbaszadegan, Morteza,1955- January 1991 (has links)
Giardia is the most common human parasite infection in the United States causing a lengthy diarrhea. Transmission of Giardia is by the fecal-oral route and numerous waterborne outbreaks have been documented. The Environmental Protection Agency has regulated Giardia in drinking water through the "Surface Water Treatment Rule." Current methods for detection of Giardia in water rely primarily on microscopic observation of water concentrates by immunofluorescent techniques. We evaluated the efficacy of using a gene-specific probe for the detection of Giardia species in water. A cDNA probe, 265 base pairs long, from the small subunit of rRNA of Giardia lamblia was used for detection of cysts. The replicative form of M13 vector with insert was isolated from lysed host E. coli XL1- Blue and used for production of the cDNA probe by nick translation with ³²P-labeled nucleotides. Seven different protocols were tested for extracting nucleic acids from the cysts. Using the most efficient procedure, disrupting Giardia cysts with glass beads in the presence of proteinase K, as few as 1 to 5 cysts per ml can be detected in water sample concentrates by dot-blot hybridization assays. Environmental concentrates from secondary and tertiary treated sewage or surface waters were screened for Giardia cysts by immunofluorescent and the genespecific probe. Positive signals were observed in sewage and surface water samples without floatation at ten fold greater dilutions than after floatation. It appeared that gene probe detection was slightly more sensitive than microscopic detection of Giardia cysts for wastewater samples. In six surface water samples and two sewage sample no positive results were found either by the cDNA probe or immunofluorescent. Usually, DNA probes are radiolabeled and the most commonly used is ³²P. ³²P is expensive, hazardous and has an extremely short half-life of 14.3 days, necessitating frequent preparation of the nucleic acid probes. Three non-radioactive labeling methods, chemiluminescence, enzyme-linked immunoassay and enhanced chemiluminescence were evaluated. The cDNA probe was labeled by nick translation for chemiluminescence method. Biotinylated deoxyuridine triphosphate was used in place of deoxythymidine triphosphate to produce biotinylated DNA strands. The result of hybridization was visualized by chemiluminescenct detection of DNA. The sensitivity of the chemiluminescent method and the 32P labeled probe was 0.1 pg of DNA in a slot-blot hybridization assay.
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Removal of bacteria by reverse osmosis method.Anyahuru, Emmanuel Achonna. January 1972 (has links)
No description available.
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The health-related microbial quality of drinking water from ground tanks, standpipes and community tankers at source and point-of-use in eThekwini Municipality : implications of storage containers, household demographics, socio-economic issues, hygiene and sanitation practices on drinking water quality and health.Singh, Urisha. January 2009 (has links)
The aim of this study was to investigate the microbiological quality of drinking water at the
source (taps at eThekwini laboratories, standpipes and mobile community tankers) and
corresponding point-of-use (storage containers and ground tanks) supplied to peri-urban areas
in Durban by eThekwini Municipality. It also aimed to identify factors associated with
deterioration in water quality such as storage of water, household demographics, hygiene and
sanitation practices. In order to determine the microbial quality of drinking water, the pour
plate method (for enumeration of heterotrophic organisms) and the membrane filtration
technique (for total coliforms and E. coli enumeration) were used. Conductivity, turbidity, pH
and total and residual chlorine levels of drinking water were measured. Microbial and
physico-chemical data was collated and statistically analysed with epidemiological data from
an associated study to determine the link between microbial quality of drinking water,
household demographics, health outcomes, socio-economic status, hygiene and sanitation
practices. Findings showed that all point-of-use water was unsafe for human consumption as
a result of either poor source water quality, in the case of standpipes, and microbial
contamination at the point-of-use, in the case of ground tanks and community tankers. The
latter could be attributed to unsanitary environments, poor hygiene practices or poor wateruse
behaviour. Households which included children aged 0-5 years and in which open-top
containers were used for water storage had the highest rates of diarrhoea and vomiting. Water
from ground tanks had the best microbial quality but people in households using this water
presented with the highest rate of diarrhoea. Therefore provision of microbially safe drinking
water will not reduce the rate of health outcomes if addressed in isolation. In order to reduce
water-associated illness, provision of safe and adequate amounts of water, hygiene and
sanitation education and education on water-use behaviour should be provided as a package.
The provision of improved water delivery systems does not ensure that drinking water is safe
for human consumption. Measures, such as point-of-use water treatment should be
considered to ensure that drinking water provided at the source and point-of-use is
microbially safe for human consumption. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.
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