Inhibition of Listeria monocytogenes by freeze-dried piscicocin CS526 fermentate in food

AIMS: The effectiveness of freeze-dried powder, fermented with bacteriocin producing Carnobacterium piscicola CS526, was evaluated for the inhibition of Listeria monocytogenes in a food model. METHODS AND RESULTS: A 10% solution of milk whey powder was fermented with a bacteriocinogenic C. piscicola CS526 Bac(+) or its nonbacteriocinogenic mutant strain CS526 Bac(-) at 30 degrees C for 12 h and freeze-dried. The freeze-dried piscicocin CS526 Bac(+) fermentate exhibited strong anti-listerial activity even at a concentration of 1% (w/v) in sterile water (pH 7), but the piscicocin CS526 Bac(-) fermentate and nonfermented whey powder had no anti-listerial activity. In the presence of 10% piscicocin CS526 Bac(+) fermentate, L. monocytogenes in ground meat rapidly decreased from 10(5) CFU g(-1) to less than the detection limit (3.0 x 10(3) CFU g(-1)) within 5 and 1 days at 4 and 12 degrees C, and was bacteriostatically inhibited for 25 and 4 days at 4 and 12 degrees C respectively. Furthermore, this inhibitory effect was enhanced at lower temperatures. CONCLUSIONS: Piscicocin CS526 Bac(+) fermentate was effective for the control of L. monocytogenes in a food model at refrigeration temperatures. SIGNIFICANCE AND IMPACT OF THE STUDY: A freeze-dried bioactive piscicocin CS526 Bac(+) powder can be a powerful tool to ensure food safety against L. monocytogenes contamination in refrigerated foods such as ready-to-eat products.     

Multiple Neurite Formation in Neuroblastoma Cell Lines by Griseolic Acid, a Potent Inhibitor of Cyclic Nucleotide Phosphodiesterases

The morphological change of several neuroblastoma cell lines induced by griseolic acid, a novel and potent inhibitor of cyclic nucleotide phosphodiesterase (PDE), was examined. In the cell lines tested, Neuro-2a (a murine neuroblastoma cell line) showed dose-dependent (1 microM-1 mM) neurite extension. Griseolic acid markedly increased the intracellular cyclic AMP level of Neuro-2a cells, suppressed DNA synthesis (82% at 1 mM), and induced multipolar (multiple-neurite-bearing)-type neuritogenesis. A similar type of neurite outgrowth was induced by 8-bromo-cyclic AMP, which also elevated the intracellular cyclic AMP concentration. In contrast, when Neuro-2a cells were treated with retinoic acid, neurite formation was of the monopolar (single-neurite-bearing) type. Papaverine and theophylline, which have been frequently used as PDE inhibitors, failed to induce these morphological changes up to 1 mM, probably owing to the lesser potency of these compounds as compared with griseolic acid on the inhibition of PDE. Retinoic acid, theophylline, and papaverine were ineffective at elevating the intracellular cyclic AMP level. These results suggest that multipolar-type cell shape change in Neuro-2a cells is correlated with the accumulation of intracellular cyclic AMP and that griseolic acid is a useful compound to induce neuroblastoma cells into terminal differentiation.     

Immunological detection of adulteration of ground meats by meats of other origins

Specific and sensitive assays for immunoglobulin G in pork, chicken, and beef were developed using polyester cloths coated with respective anti-immunoglobulin G antibodies. The captured immunoglobulin G proteins were detected by their reactions with the respective IgG antibody horseradish peroxidase conjugates and a chromogenic peroxidase substrate. This sensitive assay takes only 30 minutes and can detect the adulteration of ground meats.     

The Chemistry and Stereochemistry of Cercosporin

The structure of cercosporin, a deep red photosensitizing pigment isolated from the cultured mycelia of Cercospora kikuchii (Matsumoto et Tomoyasu) Gardner, has been elucidated as 1,12-bis(2-hydroxypropyl)-2,11-dimethoxy-6,7-methylenedioxy-4,9-dihydroxyperylene-3,10-quinone(Ia). All substituents are symmetrically arranged and the molecule has a two-fold rotation axis. An unusual seven-membered methylenedioxy bridged system endows the molecule with the inherently dissymmetric nature. Isocercosporin(Ib), a stereoisomer of Ia, was separated and the stereochemistry and the molecular dissymmetry of both isomers were also discussed.     

Alterations of lymphocyte count and platelet volume precede cerebrovascular lesions in stroke-prone spontaneously hypertensive rats

Abstract

Background: Cerebral small vessel disease (CSVD) is associated with future stroke. Although pathological alteration in small vessels of patients with CSVD can be detected by neuroimaging, diagnosis of CSVD is delayed because it is an asymptomatic disease. The stroke-prone spontaneously hypertensive rat (SHRSP) show similar pathological features to human CSVD and develop stroke-related symptoms with advancing age.

Objective: We investigated the time course of haematological parameters in Wistar rats and SHRSP.

Material and Methods: Blood cells were analysed using an automated haematological analyser.

Results: SHRSP develop stroke-related symptoms including onset of neurological symptoms, decreased body weight and blood brain barrier leakage between 12 and 14?weeks of age. Lymphocyte counts were gradually decreased at 3?weeks before development of stoke-related symptoms and then were further decreased after the development of stroke-related symptoms. The both mean platelet volume and large platelet ratio gradually increased at 3?weeks before the development of stoke-related symptoms. However, although SHRSP showed more microcytic red cells than Wistar rats, the trajectories of change in erythrocyte-related parameters were similar between Wistar rats and SHRSP.

Conclusion: Our pilot study suggests that alterations of lymphocyte count and platelet volume predictive indicators for asymptomatic CSVD and symptomatic stroke in SHRSP.     

New clade of silicified bolidophytes that belong to Triparma (Bolidophyceae,Stramenopiles)

The small phytoplankton genus Triparma belongs to the class Bolidophyceae and contains two distinct forms: silicified species and naked flagellated species (formerly Bolidomonas). Recent studies showed that four silicified species/strains (Triparma laevis f. inornata, T. laevis f. longispina, T. strigata, and T. aff. verrucosa) belong to a single clade that is paraphyletic, because it also contains an unclassified flagellated strain, and is sister to a flagellated species, T. eleuthera. In this study, we isolated and characterized two new strains of silicified species to test the phylogenetic unity of silicified bolidophytes. The isolates were identified as T. retinervis strains because they possessed fine areolation on the cell wall. 18S rDNA and rbcL phylogenetic analyses demonstrated that T. retinervis formed a new silicified clade that is sister to the flagellated species T. pacifica. This reveals that there are at least two distinct clades including both silicified and flagellated Triparma species.