Characterization of the spoilage potential of pure and mixed cultures of bacterial species isolated from tropical yellowfin tuna (Thunnus albacares).

AIM: The spoilage potential of 28 bacterial strains isolated from spoiled raw yellowfin tuna was evaluated. METHODS AND RESULTS: Bacterial species were inoculated in irradiated tuna matrix. Chemical changes, bacterial growth and sensory quality were monitored during aerobic storage at 8°C. Pseudomonas spp., Enterobacter spp. and Escherichia hermanii had no spoiling effect. Brochothrix thermosphacta and Carnobacterium divergens/maltaromaticum developed moderate unpleasant odours. Hafnia paralvei and Serratia spp. released strong off-odours (pyrrolidine, sulphur/cabbage). No bacterial group (except H. paralvei) combined with Pseudomonas spp. deteriorated the sensory quality of tuna. When C. divergens/maltaromaticum was associated with H. paralvei or B. thermosphacta, the odour is close to the naturally contaminated tuna stored on the same conditions. The pH, total volatile basic nitrogen (TVBN) and trimethylamine (TMA) were not correlated with the spoilage. CONCLUSIONS: The bacterial species had a different impact on the sensory quality of the fish. The bacterial interactions lead to an enhancement or an inhibition of the spoilage potential and the bacterial growth. SIGNIFICANCE AND IMPACT OF STUDY: The specific spoilage organism (SSO) appears to be an association of lactic acid bacteria (LAB) with Enterobacteriaceae or B. thermosphacta. Pseudomonas, often dominant at the sensory rejection time, is not a good quality indicator.

Trends in colorectal cancer in the Caribbean: A population-based study in Martinique, 1982-2011.

BACKGROUND: We aimed to describe incidence and mortality from colorectal cancer, and temporal trends between 1982 and 2011 in Martinique (French West-Indies). METHODS: This was a descriptive, longitudinal, observational study based on data from the Martinique cancer registry. The study included all incident cases of colorectal cancer between 1982 and 2011. We recorded sociodemographic data and clinical variables (histology, site according to the WHO classification). Cancer cases were recorded in strict conformity with the international standards. Annual rate of change was calculated, direct standardisation was used for incidence and mortality age standardised rates (ASR). The comparative incidence figure and comparative mortality figure (95% confidence intervals) were calculated. RESULTS: In total, 2530 patients were included in our study; 1243 died. In the period 2007-2011, a considerable increase in incidence was observed, making colorectal cancer the second leading cause of cancer deaths in both sexes (8.9% and 10.5%). In men, ASR for incidence increased from 9.6/100,000 person-years in the period 1982-1986 to 27.2/100,000 person-years in the period 2007-2011, with a notable acceleration of the increase. In women, ASR increased from 8.4 to 19.8/100,000 person-years over the same periods. For the latest period 2007-2011, mortality rates were 9.9 and 7.6/100,000 person-years for men and for women respectively. Regardless of the sex, there was a strong increase in the incidence of right colon cancer, which became the most common colorectal site in women in Martinique. CONCLUSION: Our findings confirm the increase in the incidence of colorectal cancer that started in the 2000s. Trends observed reflect a salient epidemiological transition of the Caribbean.

[Colorectal cancers in Martinique: incidence and mortality rates over a period of 20 years]. / Cancers colorectaux en Martinique: incidence et mortalité durant une période de 20 ans.

BACKGROUND: Colorectal cancer is the second leading cause of cancer death in Western countries, with an incidence progressively increasing in developing countries. Worldwide, colorectal cancer is the second and third leading cause of death by cancer in females and males respectively. According to the Martinique Cancer Register data, colorectal cancer is the second leading cause of death by cancer in women, and the fourth in men. Colorectal cancer exhibits a variable distribution worldwide. This study was conducted to observe variations in colorectal incidence and mortality rates observed over a twenty-year period. Such data will be useful for monitoring changing trends related to onset of an organized screening program. METHOD: Patients with colorectal cancer diagnosed from 1981 to 2000 in Martinique were included in this study. Data are obtained from the Martinique Cancer Register. RESULTS: The incidence of colorectal cancer in Martinique (16/100,000 and 17/100,000 in the female and male population respectively in the year 2000) is intermediary compared with other countries worlwide. There is a current trend towards increased incidence and mortality. The incidence has increased for cancers localized in the proximal colon, the sigmoid colon and the rectum. CONCLUSION: The increasing incidence of colorectal cancer in all localisations raises concern in Martinique. A significant predominance of colorectal cancer incidence among the male population in Martinique was not observed. Gender and age do not appear to imply any preferential localisation of colorectal cancer.

Resveratrol, a natural dietary phytoalexin, possesses similar properties to hydroxyurea towards erythroid differentiation.

Resveratrol, a natural dietary polyphenol, has been postulated to be implicated in the cardioprotective effect of red wine and the low incidence of breast and prostate cancers among vegetarians and Orientals respectively. This compound inhibits ribonucleotide reductase as does hydroxyurea, the first therapeutic agent used in the treatment of sickle cell disease. Using the human erythroleukaemic K562 cell line as an in vitro model, we show here that 50 micromol/l of resveratrol induced a higher haemoglobin production (sevenfold) in K562 cells than 500 micromol/l of hydroxyurea (3.5-fold). This erythroid differentiation was linked to a dose- and time-dependent inhibition of cell proliferation associated with an equivalent increased expression of p21 mRNA, but with a higher increased level of p21 protein (sixfold) for cells treated with resveratrol than for those treated with hydroxyurea (1.5-fold). We also show that 50 micromol/l of resveratrol and 25 micromol/l of hydroxyurea induced variable but similar enhancements of fetal haemoglobin synthesis in cultured erythroid progenitors for the majority of the sickle cell patients studied. These inductions were linked to, but not correlated with, a variable decrease in erythroid burst-forming unit clone number. Taken together, these results show that resveratrol merits further investigations in sickle cell disease therapy.

The detection of K-ras mutations in colorectal cancer using the amplification-refractory mutation system.

A total of 301 colorectal carcinoma (CRC) archival samples were analysed using the amplification-refractory mutation system (ARMS). Each sample was examined to determine the mutation status of codons 12 and 13 of the K-ras oncogene. The results from direct DNA sequence analysis carried out on 30 of the samples differed from the ARMS result in almost 50% of the cases as a result of the relative excess of wild-type to mutated DNA sequences. To assess the validity of the ARMS data, the polymerase chain reaction (PCR) was used to generate an amplicon from K-ras exon 1 from 23 of the samples. The PCR amplicons were cloned and sequenced, and the DNA sequence analysis of the cloned material was in agreement with the ARMS results in all but one case. This case represented a tumour that exhibited a five-nucleotide reversed inversion. The cloned sequence data confirm the sensitivity and specificity of the individual ARMS reactions and that it is possible in certain cases to detect additional, more complex, sequence variations.

Detection of c-Ki-ras mutations in faecal samples from sporadic colorectal cancer patients.

Colonic exfoliated epithelial cells in faecal material provide a source of human DNA which has been analysed for the presence of the tumour marker ras, in order to detect early tumour cells. The stool samples were subjected to a preliminary sample preparation step followed by centrifugation. DNA was extracted from both the centrifugation pellet and supernatant fractions, as well as from endoscopy washings, using a conventional phenol chloroform extraction method and was then purified on glass milk or spin columns. The purified DNA was amplified using mitochondrial primers and analysed for ras mutations using a non-radioactive, allele specific mismatch method. Corresponding tumour DNA was analysed for mutations using the same method. The results show that approximately 50% of the faecal samples analysed exhibited the presence of ras mutations which were also observed in the corresponding tumours. A double mutation was detected in one supernatant. Our findings represent an important stage in the development of a diagnostic test for the early detection of colorectal cancer.

APC mutation associated with late onset of familial adenomatous polyposis.

Familial adenomatous polyposis is an autosomal dominantly inherited disorder. Mutation studies in the corresponding gene (APC) may provide information for predictive tests for persons at risk in affected families. We report here a new mutation in exon 6 (codon 233) of the APC gene and clinical data in a large family with late onset of the disease in most affected persons.

Phenotypic expression in familial adenomatous polyposis: partial prediction by mutation analysis.

The phenotypic expression in familial adenomatous polyposis (FAP) is variable. This study compares the phenotype of 27 patients with an identical 5 base pair (bp) deletion at codon 1309 with a group of 61 matched patients with FAP where knowledge of specific mutations is not available and with seven other different mutations in 24 subjects. Patients with the codon 1309 deletion have significantly more colorectal polyps at the time of colectomy than age and sex matched FAP controls (p = 0.0001). The median number of polyps in colectomy specimens of patients with the deletion at codon 1309 was 4000 (interquartile (IQ) range 3000-4875), compared with 600 (IQ range 488-1400) in the matched controls. Mutations at codon 1323, 1407, and 233 were also associated with large numbers of polyps. Desmoid disease and extracolonic cancers were more common with the mutation at codon 1309 (p = 0.003). In conclusion, there may be a correlation between a specific germline mutation and the number of large bowel polyps. There is residual heterogeneity in phenotypic expression, however, and this may result from the influence of other genes, specific environmental factors or chance.

Characterization of two monoclonal antibodies (UCL4D12 and UCL3D3) that discriminate between human mantle zone and marginal zone B cells.

Two new monoclonal antibodies (MoAbs), UCL3D3 and UCL4D12 were obtained following immunization with follicular lymphoma (UCL3D3) or low-grade primary B cell gastric lymphoma cells (UCL4D12). In normal splenic white pulp, tonsil and small intestinal Peyer's patches, UCL4D12 recognizes marginal zone B cells and a subpopulation of follicle centre cells, whereas mantle zone B cells are UCL4D12 negative. In contrast, UCL3D3 recognizes mantle zone B cells and follicular dendritic cells, but not marginal zone B cells or follicle centre B cells. Double-immunofluorescence studies showed that in the splenic white pulp, these antibodies stain reciprocally. The majority of UCL3D3+ cells are sIgM+ and sIgD+ whereas a higher proportion of UCL4D12+ cells express surface IgM (sIgM) but not surface IgD (sIgD). Less than 10% of splenic B cells express both 3D3 and 4D12 antigens. None of the cell lines tested expressed either antigen. Functional studies showed that both antigens play a role in B cell activation as the MoAbs increase the mitogenic effect of Staphylococcus aureus Cowan I on tonsil B cells. This effect was maximal at 72 h in culture. TPA activation was reduced, and no effect was observed with anti-immunoglobulin (anti mu) or CDw40 (G28.5). UCL3D3 and UCL4D12 did not show any stimulatory effect on their own. Biochemical studies show that both MoAbs recognize proteins of 80-90 kD under reducing conditions. These two MoAbs appear to recognize new B cell surface antigens which may be useful for identifying subpopulations of B cells.

Use of damaged plasmid to study DNA repair in X-ray sensitive (xrs) strains of Chinese hamster ovary (CHO) cells.

The effect of gamma-irradiation of pSV2gpt DNA on its transfection frequency has been analysed using CHO xrs mutants. Xrs mutants are sensitive to ionizing radiation and show a defect in double-strand break (dsb) rejoining. At low doses a sharp decrease in relative transfection frequency, i.e. transfection frequency of irradiated plasmid relative to untreated plasmid, was observed in the xrs mutants compared with the parent line K1. Electrophoresis of the irradiated plasmid DNA showed that the decrease in transfection frequency in the xrs mutants correlated with the change of supercoiled molecules into open-circular forms. One explanation for these results is that the xrs gene could play a part in the integration or repair of open-circular molecules produced by gamma-radiation. In the parent line CHO-K1, open-circular and supercoiled molecules have the same transfection frequency. The effect of linearization of pSV2gpt DNA by restriction enzymes on transfection frequency in xrs and wild-type strains has also been examined. In contrast to the above results we have not detected a difference in the relative transfection frequency between xrs and wild-type strains. The results suggest that restricted plasmid DNA is subject to extensive nucleolytic degradation, and this occurs to equal extents in wild type and mutant strains.

Decreased stable transfection frequencies of six X-ray-sensitive CHO strains, all members of the xrs complementation group.

Six X-ray-sensitive strains (xrs) of the Chinese hamster ovary (CHO) cell line, all of which have a defect in double-strand break (dsb) rejoining, have been investigated for their proficiency in DNA transfection assays. All 6 strains and clonal isolates derived from them, show a decreased stable transfection frequency using the plasmids pSV2neo and pSV2gpt after transfection by either the CaPh method or the polybrene method. The magnitude of this effect is DNA concentration dependent and is more marked after transfection with higher DNA concentrations (5-20 micrograms DNA). A spontaneous X-ray-resistant reactivant (or revertant) of one xrs strain also acquired the elevated transfection frequency of the wild-type strain providing evidence for a causal relationship between the decreased transfection frequency and the xrs phenotype. In contrast, the strains show no defect when transfection is assayed using a transient transfection system. Since the transient transfection assay only depends on the uptake and transcriptional activity of foreign DNA, and does not necessitate DNA integration, this suggests that the xrs strains do not have a defect in the uptake of foreign DNA, but might have a defect in integration or the processing of DNA molecules prior to integration.