Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli

Collagen type VI α5 gene variations may predict the risk of lung cancer development in Chinese Han population

The abundant expression of collagen type VI α5 (COL6A5) exists in lung tissue, and its role in lung cancer is still unknown. We performed a genetic association study with an attempt to detect the relationships between single nucleotide polymorphisms (SNPs) in COL6A5 and lung cancer predisposition in Chinese Han population. We finally selected six tag-SNPs to determine their genotypes among 510 lung cancer patients and 495 healthy controls with the MassARRAY platform. The associations of SNPs and lung cancer risk were estimated by logistic regression method with adjustment for confounding factors. Two available databases were used for gene expression and prognosis analysis. COL6A5 rs13062453, rs1497305, and rs77123808 were significantly associated with the risk of lung cancer in the whole population or stratified subgroups (p < 0.05). Among them, COL6A5 rs13062453 and rs1497305 were also linked to the susceptibility of lung adenocarcinoma. Additionally, rs1497305 was found to be strongly related to the TNM staging under five genetic models (p < 0.05). Results from databases suggested the important role of COL6A5 in lung cancer development. COL6A5 polymorphisms rs13062453, rs1497305 and rs77123808 were associated with lung cancer risk in Chinese Han population. These findings first yield new insight of COL6A5 in lung cancer.

16 Methods for Detecting Microbial Pathogens in Food and Water

Newly developed methods for the detection of bacteria and viruses have provided microbiologists with the means to rapidly identify and monitor specific microorganisms in food and water. Traditional methods of testing involve culture techniques to increase the numbers of the organism to a detectable level, followed by isolation and biochemical identification. This chapter focuses on the methodologies to detect pathogens and indicator organisms; however, the methods described are applicable to most bacteria. As detection and isolation methods have improved, a growing number of pathogens have been identified as important food- and waterborne pathogens. This chapter describes the use of nucleic acid and antibody probes that have the potential to circumvent the need to culture the organism prior to identification. Nucleic acid probes have become a valuable diagnostic reagent in the identification of human and animal pathogens and have made possible the identification of viruses and bacteria that are difficult, if not impossible, to cultivate. DNA probes have also proved to be a useful tool for identifying and monitoring the organisms in food and the environment.

Shedding of Escherichia coli O157:H7 in dairy cattle housed in a confined environment following waterborne inoculation

A study of Escherichia coli O157:H7 transmission and shedding was conducted with bull calves housed in individual pens within a confined environment. For comparative purposes, the numbers and duration of E. coli O157:H7 shedding in naturally infected calves were monitored after a single purchased calf (calf 156) tested positive prior to inoculation. During the next 8 days, the calves in adjacent pens and a pen directly across a walkway from calf 156 began to shed this serotype O157:H7 strain. Five of the eight calves in this room shed this O157:H7 strain at some time during the following 8 weeks. The numbers of E. coli O157:H7 isolates shed in these calves varied from 60 to 10(5) CFU/g of feces, and the duration of shedding ranged from 17 to >31 days. The genomic DNAs from isolates recovered from these calves were indistinguishable when compared by using XbaI digestion and pulsed-field gel electrophoresis. Inoculation of calves with 1 liter of water containing ca. 10(3) to 10(4) CFU of E. coli O157:H7/ml resulted in shedding in 10 of 12 calves (trial 1, 4 of 4 calves; trial 2, 6 of 8 calves). The inoculated calves shed the inoculation strain (FRIK 1275) as early as 24 h after administration. The duration of shedding varied from 18 to >43 days at levels from 10(2) to 10(6) CFU/g of feces. The numbers of doses necessary to initiate shedding varied among calves, and two calves in trial 2 never shed FRIK 1275 after four doses (ca. 10(6) CFU per dose). Results from this study confirm previous reports of animal-to-animal and waterborne dissemination of E. coli O157:H7 and highlight the need for an effective water treatment to reduce the spread of this pathogen in cattle.

A novel gene encoding a 54 kDa polypeptide is essential for butane utilization by Pseudomonas sp. IMT37

Twenty-three propane- and butane-utilizing bacteria were isolated from soil samples collected from oilfields. Three of them have been identified as Rhodococcus sp. IMT35, Pseudomonas sp. IMT37 and Pseudomonas sp. MT40. SDS-PAGE analysis of the membrane of Rhodococcus sp. IMT35 revealed the presence of at least four polypeptides induced by propane. Polyclonal antibody raised against a 58 kDa polypeptide from Rhodococcus sp. IMT35 specifically detected bacteria which were actively utilizing propane or butane. Immunoscreening of a genomic library in lambdagt11 with this antibody resulted in isolation of a clone containing a 4.9 kb EcoRI genomic DNA fragment. This 4.9 kb DNA fragment was found to hybridize specifically with organisms which could grow on propane or butane. This fragment could therefore be used as a probe for detection of such bacteria. A 2.3 kb fragment having an ORF encoding a polypeptide of 54 kDa was identified by screening a genomic library of Pseudomonas sp. IMT37 with this 4.9 kb EcoRI fragment. The sequence of the ORF (designated orf54) was found to be novel. Primer extension and S1 nuclease mapping showed that transcription of the ORF starts at base 283 and it had sequences upstream similar to that of a Pseudomonas promoter (-12, -24 type). Disruption of the ORF by a kanamycin ('kan') cassette prevented the organism from growing on any alkane but did not affect its ability to utilize the respective alkanols and acids, indicating that alcohol dehydrogenase and subsequent steps in the pathway remained unaltered. The mutants had no detectable level of butane monooxygenase activity. Therefore, the product of this gene plays a crucial role in the first step of the pathway and is an essential component of monooxygenase. The findings imply that this bacterium either employs a common genetic and metabolic route or at least shares the product of this gene for utilization of many alkanes.

Modulation of brain catecholamine absorbing proteins by dopaminergic agents

Catecholamine absorbing proteins (CATNAPs) are localized in the brain and thus far have no known biochemical and pharmacological characteristics consistent with other receptor proteins or metabolic enzymes in the central nervous system. The oxidative metabolism of catecholamines in the brain, especially the catabolism of dopamine and its conjugation with metabolic brain proteins, results in the production of highly toxic free radicals. Since such processes are implicated in the pathophysiology of various neurodegenerative diseases, including parkinsonism, and since CATNAPs bind catecholamines with high affinity, there is a need to further investigate if these novel proteins could play a protective role against these harmful catecholamine metabolites. In this study, we demonstrate the purification, pharmacological characterization and modulation of CATNAPs, as the first steps necessary to elucidate the function of these proteins in the brain. First, CATNAPs were identified from tissues using [3H]N-n-propylnorapomorphine (a specific dopamine receptor agonist) and [125I]6-hydroxy-5-iodo[N(N-2,4-dinitro-phenyl)- aminopropyl]1,2,3,4-tetrahydronaphthalene ([125I]DATN; a highly specific ligand synthesized in our laboratory). Three proteins, with molecular masses of 47, 40 and 26 kDa, were identified and purified, which allowed for the subsequent production of antibodies against each of these CATNAPs. The effects of in vivo chronic administration of several dopaminergic agents on CATNAPs were also examined by Western immunoblotting. L-3,4-Dihydroxyphenylalanine (L-DOPA) treatment in rats resulted in the increase of all of the three proteins, as compared to controls. Treatment in rats with the dopamine depleting agent, reserpine, produced a significant decrease in all of the three CATNAPs. In addition, the effects of direct administration of apomorphine, dopamine, epinephrine, isopropylnorepinephrine, norepinephrine, N-n-propylnorapomorphine and 6-hydroxydopamine on CATNAP levels in rats were examined. Interestingly, we observed an increase (as compared to control) of the 47, 40 and 26 kDa proteins in animals treated with dopamine, norepinephrine, N-n-propylnorapomorphine and apomorphine. In contrast, animals treated with 6-hydroxydopamine showed significant decreases in the levels of all three proteins. It is evident that as the concentration of catecholamines increases, there is a corresponding increase in the levels of CATNAPs in the brain. These results clearly demonstrate the pharmacological modulation of CATNAPs by dopaminergic agents and suggest their possible role in the cytoprotection against damage caused by free radicals generated by oxidative stress.

Improvement of antisera raised against complex antigen mixtures by the use of heterologous sources of antigen for immunization

Polyspecific antisera against antigen mixtures are important tools for many experimental purposes. However, following immunization with extracts containing a great number of different proteins, many antigens remain non-immunogenic. Therefore, the improvement of the antibody spectrum of antisera is an essential goal in maximising the power and applicability of many serological analyses. In the present report we demonstrate that the additional use of heterologous (i.e., antigenically related, but not identical) antigen mixtures for immunization increases the variety of antibodies in polyspecific antisera as well as the antibody titer against weak immunogens.

Enzyme immunoassay for identification of Vibrio vulnificus in seawater, sediment, and oysters

Historically, methods used to identify Vibrio vulnificus in environmental samples have been inadequate because isolation and identification procedures are time-consuming and fail to separate V. vulnificus from other bacterial species. We describe an enzyme immunoassay (EIA) and culture techniques which identified V. vulnificus in seawater, sediment, and oysters. The EIA used monoclonal antibody FRBT37 to a species-specific epitope of V. vulnificus. No cross-reactions were observed among 72 non-V. vulnificus strains comprising 34 species and 15 genera. In field trials, the EIA identified correctly 99.7% of 348 biochemically confirmed V. vulnificus isolates. The epitope corresponding to FRBT37 was found in cells lysed by Triton X-100, deionized H2O, and ultrasonication but was not found in culture supernatants, indicating that its location was intracellular. In addition, electron micrographs of V. vulnificus labeled with FRBT37-biotin-avidin-gold showed that epitope FRBT37 reacted with fragments of lysed cells but not whole cells. FRBT37 was expressed when V. vulnificus was cultured in different growth media. The minimum level of detection of the EIA was approximately 2,000 V. vulnificus cells per EIA well. Epitope FRBT37 was labile at 70 degrees C for 30 min. Immunoblot and EIA plate formats reduced assay time and facilitated handling large numbers of test samples.

Antigenic property of pediocin AcH produced by Pediococcus acidilactici H

Pediocin AcH, a bacteriocin of Pediococcus acidilactici H, inhibits the growth of several food spoilage and pathogenic bacteria. The antigenic property of partially purified pediocin AcH was tested by immunizing mice and a rabbit. Pediocin AcH was not immunogenic in these animals as determined by immunoblotting even after conjugation to bovine serum albumin. The non-immunogenic nature of pediocin AcH, its non-toxicity to laboratory animals and its hydrolysis by gastric proteolytic enzymes may be considered favourably in its possible use as a food preservative.

Production of Escherichia coli-specific hybridomas by using gnotobiotic mice

Monoclonal antibodies provide a rapid and specific means of direct detection of microorganisms in water and food samples. However, monoclonal antibodies specific for some bacteria are difficult to obtain; a good example of such a bacterium is Escherichia coli. Gnotobiotic BALB/c mice immunized with whole-cell preparations of heat-treated strains of E. coli and subjected to high-frequency antigen injection showed a significant increase in the number of specific hybridomas produced. Fusions obtained by using regular BALB/c mice immunized by using standard immunization protocols produced nonspecific hybridomas. Twenty-one stable hybridomas that did not cross-react with Klebsiella pneumoniae ATCC 13883 or Citrobacter freundii 1604770 were obtained from gnotobiotic mice. The bacterial strains were selected for the specificity tests because of their high cross-reactivity, which has been detected in previous fusion experiments. The method of immunization described here offers the potential of improving the production of highly specific hybridomas for bacteria which have been difficult to obtain.

Occurrence and characteristics of agglutination of Vibrio cholerae by serum from the eastern oyster, Crassostrea virginica

Cell-free hemolymph (serum) of the eastern oyster, Crassostrea virginica, agglutinated Vibrio cholerae, including all O1 serovars and biovars. Seventy-nine other strains of bacteria, including 14 genera and 26 species, were not agglutinated. The A, B, and C factors of O1 antigen were not involved in agglutination. Bacterial agglutinating (BA) activity was demonstrated for oysters inhabiting different environments of the U.S. Atlantic and Gulf coasts. Oyster serum BA titers showed high individual variation. The serum component(s) involved in BA was inhibited by 80 degrees C heat, pronase, EDTA, mucin, and fetuin treatments. N-Acetylneuraminic acid (10 mg/ml) weakly inhibited BA activity. Ligands of V. cholerae were sensitive to neuraminidase and resistant to 80 degrees C and pronase. High salinities (24 and 30%) enhanced BA. Cross-adsorption tests with V. cholerae and human O+ erythrocytes indicated that BA and hemagglutinating activities may involve different serum components. These results imply that the ecology of V. cholerae in C. virginica is influenced by agglutinating activity of oyster serum.

Monoclonal antibodies against bacteria

Highlights are presented of most recent work in which monoclonal antibodies have been instrumental in the study of bacteria and their products. Topics summarized pertain to human and veterinary medicines, dentistry, phytopathology, ichthyology, and bacterial ecophysiology, differentiation, evolution and methanogenic biotechnology.