Molecular cloning of MSSP-2, a c-myc gene single-strand binding protein: characterization of binding specificity and DNA replication activity

We have previously reported the human cDNA encoding MSSP-1, a sequence-specific double- and single-stranded DNA binding protein [Negishi, Nishita, Saëgusa, Kakizaki, Galli, Kihara, Tamai, Miyajima, Iguchi-Ariga and Ariga (1994) Oncogene, 9, 1133-1143]. MSSP-1 binds to a DNA replication origin/transcriptional enhancer of the human c-myc gene and has turned out to be identical with Scr2, a human protein which complements the defect of cdc2 kinase in S.pombe [Kataoka and Nojima (1994) Nucleic Acid Res., 22, 2687-2693]. We have cloned the cDNA for MSSP-2, another member of the MSSP family of proteins. The MSSP-2 cDNA shares highly homologous sequences with MSSP-1 cDNA, except for the insertion of 48 bp coding 16 amino acids near the C-terminus. Like MSSP-1, MSSP-2 has RNP-1 consensus sequences. The results of the experiments using bacterially expressed MSSP-2, and its deletion mutants, as histidine fusion proteins suggested that the binding specificity of MSSP-2 to double- and single-stranded DNA is the same as that of MSSP-1, and that the RNP consensus sequences are required for the DNA binding of the protein. MSSP-2 stimulated the DNA replication of an SV40-derived plasmid containing the binding sequence for MSSP-1 or -2. MSSP-2 is hence suggested to play an important role in regulation of DNA replication.

Phorbol ester-induced reversible inactivation of cytotoxic T cell function: correlation with down-regulation of protein kinase C activity

When an H-2d-specific cytotoxic T lymphocytes (CTL) clone, FC1, was incubated in the presence of 10(-7) M phorbol myristate acetate (PMA) for 10-12 hr, the cytolytic activity of the CTL against H-2d target cells was abrogated, but was reversibly restored to the normal level after subsequent incubation of the cells in PMA-free medium for more than 10 hr. These effects of PMA have been reported (Russell, J.H.: J. Immunol. 133, 907-912 (1984)), but the mode of its action has not been fully investigated. Here, we analyzed the biochemical basis of the PMA-induced loss of cytolytic activity. Cycloheximide completely blocked the restoration of the PMA-suppressed cytolytic activity, suggesting that protein synthesis was required in this process. PMA-treatment did not affect the levels of CD3 and CD8 molecules expressed on the CTL, nor was the level of a CTL-specific serine esterase, BLT esterase, affected by this treatment. However, the target cell-induced release of BLT esterase from the CTL was suppressed if the cells were pretreated with PMA. PMA-treatment of the CTL led to the down-regulation of protein kinase C (PKC) activity by about 50%. On the other hand, staurosporin, an inhibitor of PKC, completely blocked the target cell lysis when added at 10(-6) M. These results suggest that the down-regulation of at least some isoform(s) of PKC is responsible for the PMA-induced loss of the cytotolytic activity of CTL.

Predominant suppression of anti-TNP IgE response in mice by monoclonal anti-TNP IgG1 antibody: characterization of its mode of action by in vitro and in vivo studies

It was found that an antigen-specific IgE response both in vitro and in vivo was strongly suppressed in the presence of IgG1 monoclonal antibody (mAb) against the antigen. Anti-trinitrophenyl (TNP) IgE response was elicited by the co-culture of C3H B-cells and a conalbumin (CA)-specific helper T-cell clone, D10.G4.1, in the presence of 0.1 microgram/ml TNP-CA. Addition of anti-TNP IgG1 monoclonal antibody (mAb) at 1 microgram/ml to the culture resulted in a marked (> 90%) suppression of anti-TNP IgE formation, while anti-TNP IgG1 and IgM responses were affected to a lesser extent (50-60% suppression). Similar observations were made in in vivo experiments. When 100-200 micrograms of anti-TNP IgG1 mAb was injected i.p. into BDF1 mice prior to immunization with TNP-CA, the anti-hapten (TNP) IgE response as well as the IgE response to the carrier (CA) was suppressed by 80-90%, while anti-TNP IgM production was inhibited by less than 50%. Injection of anti-TNP IgM or IgA mAb showed only marginal effects on anti-TNP IgE production. Spleen cells from anti-TNP IgG1 mAb-treated mice cultured in vitro secreted much lower levels of anti-TNP IgE spontaneously than those from untreated mice. In in vitro and in vivo experiments using the F(ab')2 of anti-TNP IgG1 mAb, an IgG1 mAb with an irrelevant specificity and mAb directed to Fc gamma RII, it was shown that the binding of the IgG1 mAb with the antigen and the interaction of its Fc portion with Fc gamma RII are required for the suppressive effects to be exerted.

Nature of protein adsorption in artificial tear solution on plasma-irradiated polymethylmethacrylate surface

To evaluate the effect of plasma treatment on protein adsorption onto a polymer surface, we carried out Ar plasma irradiation on polymethylmethacrylate (PMMA) plate and examined the adsorption behavior of protein after immersion of plasma treated PMMA plate in the artificial tear solution containing lysozyme, albumin and gamma-globulin. It was found that the total adsorption of protein in the artificial tear solution to PMMA is suppressed by the Ar plasma treatment. But the adsorption of each component protein differs according to the surface condition of polymers and obviously corresponds to the change with time in the surface wettability. It is concluded that introduction of a hydrophilic group into the PMMA surface by plasma treatment and coming off of it are associated with the adsorption behavior of proteins. Since the adsorption of protein to the plasma-treated PMMA surface changes over time, care should be exercised in determining it, when an attempt is made to clarify the effect of plasma irradiation on the adsorption to the plasma-irradiated polymer surface.

Histopathological study of intrahepatic aberrant vessels in cases of noncirrhotic portal hypertension

Aberrant vessels, which are defined as dilated blood vessels immediately adjacent to the peripheral portal tract, appear under conditions of extrahepatic portal obstruction and nodular regenerative hyperplasia as well as idiopathic portal hypertension. Our study was undertaken to compare their morphological aspects in these three disease cases. Aberrant vessels were found in 84% of cases of idiopathic portal hypertension, 67% of cases of extrahepatic portal obstruction infantile type, 78% of cases of extrahepatic portal obstruction adult type and 83% of cases of nodular regenerative hyperplasia. They were divided into three types: type I--no communication with the portal vein, the lumen of which is normally open; type II--communication with the portal vein; and type III--no communication with the portal vein, which is occluded. The most common types of aberrant vessel were type III in idiopathic portal hypertension (51%), type I in extrahepatic portal obstruction infantile type (46%), type II in extrahepatic portal obstruction adult type (43%) and type III in nodular regenerative hyperplasia (45%). Serial sections revealed transition between types I, II and III, at frequencies between types II and III, types I and II, and types I and III of 35.7%, 33.7% and 30.6%, respectively. Aberrant vessels demonstrated the same immunoreactivity as portal veins for collagen type IV, laminin, factor VIII and ulex europaeus agglutinin-I. They were concluded to arise from the vasa septalis or inlet venules, which would be used as intrahepatic shunts draining portal blood flow blocked by stenosed portal veins. Increased portal pressure would be expected to enhance development of aberrant vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

FcR gamma chain deletion results in pleiotrophic effector cell defects

The gamma subunit of immunoglobulin Fc receptors is an essential component of the high-affinity receptor for IgG (Fc gamma RIII) and is associated with the high-affinity receptor for IgG (Fc gamma RI) and the T cell receptor-CD3 complex. It is required for both receptor assembly and signal transduction. Targeted disruption of this subunit results in immunocompromised mice. Activated macrophages from gamma chain-deficient mice unexpectedly lack the ability to phagocytose antibody-coated particles, despite normal binding. Defects in NK cell-mediated antibody-dependent cytotoxicity and mast cell-mediated allergic responses are evident in these animals, establishing the indispensable role of FcRs in these responses. However, loss of gamma chain does not appear to perturb T cell development, since both thymic and peripheral T cell populations appear normal. These mice thus represent an important tool for evaluating the role of these receptors in humoral and cellular immune responses.

Enzyme release assay of human NK cell activity using beta-galactosidase-expressing K562 target cell line

In the present report, we established a K562 cell line useful for an enzyme release assay of human natural killer (NK) activity. Human myelogenous leukemia cell line, K562, was transfected with a plasmid carrying Escherichia coli beta-galactosidase (beta-gal) gene. A colony that permanently expresses the enzyme activity was isolated, and designated K562/Zneo. Incubation of K562/Zneo cells (1 x 10(4)) with nonadherent human peripheral blood lymphocytes (PBL) resulted in the release of beta-gal activity depending on the incubation time and the number of effector cells. Released beta-gal activity was assayed sensitively by using 4-methylumbelliferyl-beta-D-galactoside, a fluorescent substrate. The cytolytic activity of PBL was augmented significantly when the cells were preincubated with interleukin-2 for 20 h. This enzyme release assay showed a comparable sensitivity to that of 51Cr release assay. Thus, K562/Zneo cell line is thought to be useful for the nonradioactive assay of human NK and lymphokine-activated killer activities.

Determination of three disulfide bonds in a major house dust mite allergen, Der f II

Der f II is a major mite allergen consisting of 129 amino acid residues. Der f II contains six cysteine residues, suggesting the existence of three disulfide bonds which would stabilize this small protein. As the first step in revealing the relationship between the structure and the allergenic property of Der f II, the formation of disulfide bonds was examined. Der f II purified from Dermatophagoides farinae was treated with lysyl-endopeptidase or proline-specific endopeptidase, and the peptide fragments thus generated were separated by reverse phase high performance liquid chromatography. Determination of the amino acid sequence of each peptide collected in this way proved the existence of three disulfide bonds between Cys8 and Cys119, Cys21 and Cys27, and Cys73 and Cys78.

Enhancement of antigen-induced interleukin 4 and IgE production by specific IgG1 in murine lymphocytes

Conalbumin (CA)-specific type 2 helper T cell (Th2) clone, D10G4.1 (D10) produces IL4 when stimulated with varying doses of TNP-CA in the presence of mitomycin C-treated C3H spleen cells or purified B cells as antigen-presenting cells (APC). The production of IL4 was assessed by bioassay and by expression of IL4 mRNA. IL4 production reached maximum at 100 micrograms/ml of TNP-CA, whereas 1 microgram/ml of the antigen induced less than 10% of the maximum level of IL4. This lower level of IL4 production was augmented to the maximum level when monoclonal anti-TNP IgG1 was added to the culture at 0.5-1 microgram/ml. Anti-TNP IgE, but not anti-TNP IgM, was also effective, though IgE was 1/10 as effective as IgG1. IgG1 with an irrelevant specificity and F(ab')2 of anti-TNP IgG1 did not show augmenting effects. Moreover, the enhancement by anti-TNP IgG1 was completely abolished by monoclonal antibody against murine Fc gamma RII, 2.4G2. These results suggest that a low dose of the antigen complexed with IgG1 is focused on APC by means of Fc gamma RII, processed, and presented efficiently to the Th2 clone. On the other hand, the co-culture of D10 with normal C3H B cells in the presence of 1-100 micrograms/ml TNP-CA resulted in polyclonal IgE production. Anti-TNP IgG1 markedly augmented the lower level of IgE production induced by a suboptimal dose of the antigen (1 microgram/ml). This augmentation was shown to be dependent on endogenous IL4 because the enhancement was abolished by monoclonal anti-IL4 (11B11).

Selective regulation of antigen-specific IgE response by cyclic AMP level in murine lymphocytes

We have reported that prostaglandin E2 (PGE2) is a selective stimulator of the antigen-specific IgE response [6]. Because PGE2 is known to elevate intracellular cAMP, we investigated the regulatory role of cAMP in the production of antigen-specific IgE. Anti-TNP IgE response was induced by stimulating TNP-KLH-primed BALB/c spleen cells with the same antigen in vitro. Addition of 10-100 microM dibutyryl cAMP (DBcAMP) to the lymphocyte culture resulted in a 2-3-fold increase in anti-TNP IgE response without affecting the production of anti-TNP IgG1 or IgM. Forskolin, a stimulator of adenylate cyclase, also specifically augmented the IgE response. In contrast, 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, suppressed IgE production in an isotype-specific manner. These results suggest that IgE synthesis can be selectively modulated by intracellular cAMP level. Enhancement of IgE production by DBcAMP was observed, particularly in highly primed spleen cells, suggesting that IgE-committed B cells are subjected to regulation by cAMP.

Morphological differences between hepatocellular carcinoma and hepatocellular carcinomalike lesions

In an attempt to provide a quantitative basis for differentiation between well-differentiated hepatocellular carcinoma and hepatocellular carcinomalike lesions (focal nodular hyperplasia, regenerative nodular hyperplasia and hepatocellular adenoma), histopathological and morphometrical analyses were performed on 208 cases of various liver diseases with the aid of an image analyzer. As practical indicators for hepatocellular carcinoma, the following six morphometrical features were established: (a) nuclear shape factor of less than 0.93, (b) coefficient of variance of nuclei of more than 5%, (c) average width of trabecular cords greater than three cells, (d) nucleocytoplasmic ratio increased to more than 0.3, (e) cellular density of more than 40 liver cells and (f) individual nuclear dimension larger than 50 microns2. The manifest categories increased with dedifferentiation of cells in hepatocellular carcinoma; the number and degree of cellular and structural atypia became more prominent. Data were analyzed statistically by two multivariate analyses. Logistic analysis was able to correctly separate hepatocellular carcinoma from conditions that were not hepatocellular carcinoma, including hepatocellular carcinomalike lesions. The incidence of 13 descriptive histopathological findings such as fibrous capsule, portal triads and clear-cell clusters were also compared in hepatocellular carcinomalike lesions and hepatocellular carcinomas graded according to Edmondson's classification. Presence of a fibrous capsule, portal triads, mosaiclike patterns and tumor vessels showed statistical differences between hepatocellular carcinomalike lesions and well-differentiated hepatocellular carcinoma by the chi 2 test (p less than 0.005).

Establishment of an enzyme release assay for cytotoxic T lymphocyte activity

In the present report, we describe the establishment of a cell line that can be used as the target for measuring the activity of cytotoxic T lymphocytes (CTL) by an enzyme release assay. We transfected P3/NS1-Ag4-1 (NS-1), a myeloma cell line derived from BALB/c mice with Escherichia coli beta-galactosidase (beta-Gal) gene, and isolated a stable transformant designated as NS-1/Z that expressed a high level of the enzyme activity intracellularly. The effector cells showing cytotoxicity against NS-1/Z were induced when the spleen cells of AKR or C3H mice were cultured with mitomycin C-treated BALB/c spleen cells for 4 days. When 2 x 10(4) NS-1/Z cells were incubated with varying numbers of effector cells, beta-Gal activity was released from the target cells depending on the number of effector cells and the time of incubation for up to 8 h. A highly sensitive enzyme assay was performed by using a fluorescent substrate, 4-methylumbelliferyl-beta-D-galactoside. The cytotoxicity was specific for H-2 haplotype of the stimulator cells, and was abolished by treating the effector cells with anti-Lyt 2 plus complement. The sensitivity of the enzyme release assay was comparable to that of 51Cr release assay. These results indicate that NS-1/Z can be used as a target cell line for the non-radioactive measurement of CTL activity.

Enhancement of DNA transfection efficiency by heat treatment of cultured mammalian cells

The expression of genes introduced into various mammalian cell lines was enhanced by raising the temperature of the cells to 42 degrees C for a few hours after DNA transfection. This heat treatment resulted in an up to 10-fold increase in the frequency of the cells that transiently expressed a foreign gene such as that of beta-galactosidase, whereas it had only a limited enhancing effect on the development of stable transformants. By immunotitration analysis, it was confirmed that the enhanced expression of beta-galactosidase activity correlated well with the increase of the enzyme protein. This procedure may have an applicability for augmenting the frequency of transient gene expression in many cell types.

Manometric evaluation of esophageal function in progressive systemic sclerosis with special regard to the disease severity

A study was conducted to elucidate the relation between the severity of progressive systemic sclerosis (PSS) and the grade of esophageal function disorder, the extent of which was estimated using esophageal manometry. Fifty two patients with PSS were divided into the mild, moderate and severe groups according to the severity score established by the PSS Research Group supported by The Ministry of Health and Welfare of Japan. Primary peristaltic pressure in the esophageal body at 25 to 35cm from the incisors as well as lower esophageal sphincter pressure (LESP), which represents the function of the smooth muscle of the esophagus, were significantly decreased in parallel with the increasing severity of PSS. In contrast, there was no significant difference in upper esophageal sphincter pressure (UESP) or in primary peristaltic pressure at 20cm from the incisors, indicating that the function of striated muscle of the esophagus was not impaired. In addition, even in the mild PSS group without dysphagia (19 cases), primary peristaltic pressure in the esophageal body at 25 to 35cm from incisors was found to be significantly decreased in comparison with the control. Hence, esophageal manometry was useful for early detection of the pathophysiological state of the esophageal function in PSS.

Effect of fat emulsion in patients with liver disorders

The effect of fat emulsion in preoperative patients (n = 17) with liver disorders was studied by liver-function tests, intraoperative liver biopsy specimens, intravenous fat tolerance tests, and serum fatty acid analyses. There was no difference between liver-function tests before and after the administration of fat emulsion. Before the administration of fat emulsion, the levels of serum lipids were relatively low, and serum fatty acid patterns were abnormal. However, after the administration of fat emulsion, serum lipid levels increased, and serum fatty acid patterns became nearly normal. There was a significant correlation between the total fat intake and serum linoleic acid change before and after the administration of fat emulsion. From this equation, the total fat intake required for a normal range of serum linoleic acid was calculated to be 7 g/kg fat. These results suggest that the administration of fat emulsion improves serum fatty acid patterns without a deterioration of liver function in preoperative patients with liver disorders, but total intake of 10% fat emulsion greater than 70 ml/kg might induce higher serum fatty acids than in healthy control subjects and cause overload in these patients.

Two cases of endoscopically identified esophageal cancer of the superficial-slightly depressed type

We experienced two cases of superficial type esophageal cancer. Case 1 was a 72-year-old man in whom endoscopic examination revealed a slightly protruded, partially reddened and faded area of irregular shape corresponding to 0-IIa + IIc (slightly depressed type) of the endoscopic classification of esophageal cancers. Macroscopically, it was a superficial, ill-defined and non-cicatrized solitary tumor measuring 2.5 x 2.4 cm in size. Histologically it was a monofocal semidifferentiated squamous cell carcinoma of a swelling type of stage 0. Case 2 was 55-year-old man. Endoscopic examination disclosed an almost roundish, smooth-surfaced, flat and dull red area corresponding to IIc (slightly depressed type). Macroscopically it was a superficial, semidefined and non-cicatrized solitary tumor measuring 1.0 x 1.0 cm in size. Histologically it was a monofocal, semidifferentiated squamous cell carcinoma of stage 0. To detect esophageal cancer at an early stage, the endoscopist needs to inspect the mucosa carefully. In case of males aged over 50, the endoscopist would be well advised to employ the dye-spraying method (Lugol staining method) at the endoscopic examination.

Prostaglandin E2 as a selective stimulator of antigen-specific IgE response in murine lymphocytes

Anti-2,4,6-trinitrophenyl (TNP) IgE antibody response was elicited by stimulating TNP-keyhole limpet hemocyanin-primed murine spleen cells with the same antigen in vitro. The released anti-TNP IgE was assayed by antigen- and isotype-specific enzyme immunoassay developed in our laboratory. When prostaglandin E2 (PGE2) was added to the lymphocyte culture at 10(-7) M, anti-TNP IgE response was augmented two- to fourfold. Interestingly, PGE2 did not affect the production of anti-TNP antibodies belonging to other isotypes including IgM, IgG1, IgG2a, IgG2b, IgG3 and IgA. Moreover, PGE2 showed neither enhancing nor interleukin 4-replacing activities in the polyclonal IgE response by B cells stimulated with lipopolysaccharide and interleukin 4. When endogenous prostaglandin synthesis was inhibited by 10(-6) M indomethacin, the anti-TNP IgE response, but not the corresponding IgG response, was suppressed by 30%-60%. These results suggest a potential role of PGE2 in the up-regulation of the antigen-specific IgE response.

Cloning and sequence analysis of the cDNA for arachidonate 12-lipoxygenase of porcine leukocytes

The complete amino acid sequence of arachidonate 12-lipoxygenase (EC 1.13.11.31) of porcine leukocytes was deduced by cloning and sequence analysis of DNA complementary to its mRNA. The sequence was confirmed by automated Edman degradation of the N-terminal regions of the native enzyme and its proteolytic fragments. The cDNA had an open reading frame encoding 662 amino acid residues with a calculated molecular weight of 74,911. Amino acid residues 533-545, Cys-(Xaa)3-Cys-(Xaa)3-His-(Xaa)3-His, showed significant homology to the short cysteine- or histidine-containing sequences proposed as the metal-binding domains of transcription factors and various metal-containing proteins [Berg, J. M. (1986) Science 232, 485-487]. The amino acid sequence of 12-lipoxygenase exhibited 86% identity with human reticulocyte 15-lipoxygenase and showed 41% identity with human leukocyte 5-lipoxygenase. The 12-lipoxygenase cDNA recognized a 3.4-kilobase mRNA species in various porcine cell types, with the largest amount in leukocytes, followed by pituitary, lung, jejunum, and spleen.

DNA transfection of mouse lymphoid cells by the combination of DEAE-dextran-mediated DNA uptake and osmotic shock procedure

Several mouse lymphoid cell lines were efficiently transfected with plasmid DNA by a novel method combining DEAE-dextran-mediated DNA uptake and osmotic shock procedure. The cells were first incubated with DNA-DEAE-dextran complex, treated with hypertonic Tris-HCl buffer containing 0.5 M sucrose and 10% poly(ethylene glycol), and then exposed to hypotonic RPMI 1640 medium. This transfection protocol exhibited maximal frequencies of 0.3% and 3.10(-5) for transient gene expression and stable transformation in P3-NSI/1-Ag4-1 cells, respectively.

Cytidylate cyclase activity in mouse tissues: the enzymatic conversion of cytidine 5'-triphosphate to cytidine 3',5'-cyclic monophosphate (cyclic CMP)

Cytidylate cyclase activity, which enzymatically converts cytidine 5'-triphosphate (CTP) to cytidine 3',5'-cyclic monophosphate (cyclic CMP), has been demonstrated in mouse tissue homogenates by use of a highly sensitive enzyme immunoassay (EIA) specific for cyclic CMP. Cyclic CMP formation is dependent on the amount of homogenate and on the incubation time. Although the enzyme activity was detected at wide ranges of pH from 6.8 to 11.5, the maximal activity was observed at around pH 9.4. The optimal temperature was 37 degrees C. Cytidylate cyclase activity was almost completely lost if the homogenates were heated at 90 degrees C for 3 min prior to use. The enzyme reaction exhibited typical Michaelis-Menten kinetics with an apparent Km for CTP of approx. 0.31 mM. Cyclic CMP formation was greatly enhanced with 4 mM Mn2+, Mg2+, Co2+; Mn2+ was the most effective. Fe2+ and Ca2+ were without effect. Cu2+ and Zn2+ at a concentration of 0.1 to 0.5 mM were inhibitory to Mn2+-dependent activity. Moreover, the enzyme activity was inhibited by several nucleotides including ATP, ADP, 5'-AMP, and GTP. Cytidylate cyclase activity was found to be present in all homogenates from a variety of mouse tissues examined except heart, with the highest level found in brain, and the lowest in liver.

Fat emulsion in surgical patients with liver disorders

Total parenteral nutrition (TPN) with fat emulsion was evaluated in 68 patients with liver disorders who were admitted to the First Department of Surgery, Osaka City University Medical School. All patients received transabdominal direct operation for esophageal varices. Immediately after their operations, 28 received TPN with carbohydrate and fat emulsion as an energy source (FAT group), and 40 received TPN with only carbohydrate as an energy source (non-FAT group). Liver function tests, blood glucose levels, intravenous fat tolerance tests, serum lipid levels, fatty acid composition of serum total lipids, and nitrogen balance of the two groups were compared during postoperative TPN. The administration of fat emulsion during postoperative TPN in patients with liver disorders did not worsen the results of liver function tests and the relatively low levels of blood glucose were retained, thereby correcting the abnormalities in the fatty acid composition of serum total lipids. Rates of clearance of fat emulsion during postoperative TPN were significantly higher than in the preoperative period, and changes in serum lipid levels revealed no tendency toward retention of fat emulsion administered intravenously. Nitrogen balance and change in body weight during postoperative TPN were similar in both groups. These results suggest that for patients with liver disorders, the administration of fat emulsion is useful during postoperative TPN.

Ecology of Vibrio cholerae non-O1 and Salmonella spp. and role of zooplankton in their seasonal distribution in Fukuyama coastal waters, Japan

Seasonal variation of human pathogens such as Vibrio Cholerae non-01 and Salmonella spp. in Fukuyama coastal waters and the role of zooplankton in their distribution were studies for a period of 1 year. Comparison of two established methods, viz., the elevated temperature method and the two-step enrichment method of enumerating V. cholerae, showed that the former is superior in the recoveries of V. cholerae non-01. Isolation of this pathogen on a wider range of salinities (0.4 to 32.5%) revealed that these organisms are apparently an autochthonous component of the aquatic environment. Temperature appears to be the most crucial element in governing the distribution of V. cholerae non-01. Among the 69 isolates serotyped, 22 different serovars were identified, while one isolate failed to react with any of the known Louisiana State University antisera tested. Zooplankton samples did not harbor more V. Cholerae non-01 than the water column did. Better isolation of an allochthonous pathogen, viz., Salmonella spp., was noticed from the water samples when swabs were employed. Of the 251 isolates serotyped, 18 serotypes with three variants of Salmonella spp. were identified. A high amount of nutrients in the water column increased the survival rate of these pathogens in saline waters as evidenced by a higher incidence of various serotypes in polluted Fukuyama port than in clean marine waters. Salmonella spp. association between V. cholerae non-01 of Salmonella spp. with zooplankton could be noticed as influencing their seasonal distribution.