Identification of enterococci isolated from cow's milk cheese: comparison of the classical methods and the API 20 STREP system (technical note)

A comparison of the results obtained using the classical methods with those of the API 20 Strep system was carried out in identifying 24 enterococci strains isolated from San Simón cow's milk cheese, a traditional Spanish variety. The results of both identification systems coincided exactly in 9 strains (37.5% of the strains studied). In one strain the results obtained using the classical methods did not coincide with those using the API 20 Strep method. 3 strains (12.5%) could not be identified using the API 20 Strep system. However, 11 strains (45%), that remained doubtful between both species E. faecalis and E. faecium on the basis of the classical methods, were identified using the API 20 Strep system. The API 20 Strep system does not include some biochemical tests of importance in identifying of foodborne enterococci and could not identify the atypical strains of Enterococcus. Moreover, this system is adapted to the identification of enterococci of clinical origin and their database does not include some species common in foods. However, it could have an application in combination with the classical methods in order to carry out a reasonably rapid and reliable identification of enterococci related to cheese.     

Non-resource based territoriality in males of the butterflyXamia xami (Lepidoptera: Lycaenidae)

In the Pedregal de San Angel reserve, in Mexico City, males of the butterfly Xamia xamiperch in and defend areas with well-defined topographic limits. These areas lack concentrations of receptive females and of larvae and adult resources. One individual defends the same territory an average of 5 h/day, up to a maximum of 23 days. The same areas are used as territories by different males during the year. These areas share some characteristic features which are described. Evidence is presented in support of the hypothesis that the territories function as mating stations. A possible scenario for the evolution of this territorial mating system is advanced.     

Dihydroteugin,a neo-clerodane diterpenoid from Teucrium chamaedrys

From the aerial part of Teucrium chamaedrys a new neo-clerodane diterpenoid, dihydroteugin, has been isolated, besides the previously known diterpenoids teucrin A and teugin. The structure of dihydroteugin, (12S)-15,16-epoxy-2β,6β-dihydroxy-neo-cleroda-13(16), 14-diene-18,19:20,12-diolide, was established by chemical and spectroscopic means and by partial synthesis from teugin.     

Immunologic memory response induced by a meningococcal serogroup C conjugate vaccine using the P64k recombinant protein as carrier

In this study, we used an adoptive lymphocyte transfer experiment to evaluate the ability of the P64k recombinant protein to recruit T-helper activity and induce immunologic memory response to the polysaccharide moiety in a meningococcal serogroup C conjugate vaccine. Adoptive transfer of splenocytes from mice immunized with the glycoconjugate conferred antipolysaccharide immunologic memory to naive recipient mice. The observed anamnestic immune response was characterized by more rapid kinetics, isotype switching from IgM to IgG and higher antipolysaccharide antibody titers compared with those reached in groups transferred with splenocytes from plain polysaccharide or phosphate-immunized mice. The memory response generated was also long lasting. Sera from mice transferred with cells from conjugate-immunized mice were the only protective in the infant rat passive protection assay, and also showed higher bactericidal titers. We demonstrated that priming the mice immune system with the glycoconjugate using the P64k protein as carrier induced a memory response to the polysaccharide, promoting a switch of the T-cell-independent response to a T-cell dependent one.     

Formaldehyde and some fully n-methylated substances in boar seminal fluids. Short communication

On the basis of recent observations it is supposed that seminal fluids may contain--mainly in hydroxymethyl groups--formaldehyde (HCHO) and quaternary ammonium compounds as potential HCHO generators, therefore, preliminary investigations were carried out for the identification of these compounds in pig seminal fluids using OPLC, HPLC and MALDI MS techniques. The fresh pig seminal fluid was frozen in liquid nitrogen, powdered and aliquots (0.25 g) were treated with 0.7 ml ethanolic dimedone solution. The suspension was centrifuged and the clear supernatant was used for analysis by OPLC or after dilution with HPLC or MALDI MS technique. After OPLC separation of formaldemethone the fully N-methylated compounds which are stayed on the start point were separated by OPLC using an other eluent system. It has been established that the HCHO is really a normal component of the pig seminal fluid, as well. It can be isolated and identified in dimedone adduct form. The measurable amount of HCHO depended on the concentration applied of dimedone. According to OPLC and MALDI MS investigations L-carnitine is the main quaternary ammonium compound in pig seminal fluid which can generate a protection of the sperm cells against environmental and other influences. Considerable differences have been found among individuals concerning concentrations of quaternary ammonium compounds in the seminal fluid of pigs.     

Compounds isolated at theDepartment of Biogenesis of Natural Substances,institute of microbiology,Czechoslovak academy of sciences,in 1984–1988

A total of 41 compounds studied at theDepartment of Biogenesis of Natural Substances between 1984 and 1988 are characterized and tabulated. They include natural, semisynthetic and synthetic compounds. 1st supplement to the paper Podojilet al. (1984).     

Molecular epidemiology of plasmid mediated resistance to fosfomycin among bacteria isolated from different environments

In this report we present data on the dispersion of a gene responsible for the plasmid-mediated resistance to fosfomycin among bacteria isolated from four hospitals and seven geographically separated domestic sewage treatment plants. Colony hybridization experiments, using a 0.85 kbp DNA fragment which carried the fosfomycin resistance determinant, have shown that the gene was present in isolates from three hospitals and six sewage plants although with different incidence and that it is carried by species of Enterobacteriaceae, Pseudomonas, Acinetobacter, Staphylococcus and Bacillus .     

Thyroid Hormones affect the Level and Activity of Nitric Oxide Synthase in Rat Cerebral Cortex during Postnatal Development

The effects of thyroid hormones (TH) on the enzyme level and activity of neuronal nitric oxide synthase (nNOS) were studied in the rat cerebral cortex during postnatal life. As revealed by arginine/citrulline conversion assay and Western blot analysis of the homogenate of the parietal cortex T4 significantly increased nNOS activity and nNOS protein level to 153 ± 25% and to 178 ± 20%, respectively. In contrast, 6-n-propyl-2-thyouracil (PTU) decreased nNOS activity and nNOS level to 45 ± 10% and to 19 ± 4%, respectively. The number of nNOS-immunoreactive neurons did not change after either T4 or PTU treatment, however, following T4 administration the percentage of intensively immunoreactive neurons increased to 85 ± 3% compared to control (65 ± 6%), whereas it decreased to 49 ± 2% after PTU treatment. Our findings indicate that abnormal TH levels differentially regulate the activity and the level of nNOS and suggest a cross-talk between the TH and NO signaling pathway in the developing cerebral cortex of rats.     

Hexadecylphosphocholine interferes with the intracellular transport of cholesterol in HepG2 cells

We have shown, in a previous publication, that nontoxic concentrations of hexadecylphosphocholine exert an antiproliferative effect on HepG2 cells. Hexadecylphosphocholine also interferes with the biosynthesis of cholesterol and phosphatidylcholine. We have now extended our studies to try to establish the molecular mechanism by which hexadecylphosphocholine disrupts cholesterol homeostasis. Using radiolabelled substrates we determined the effect of hexadecylphosphocholine on cholesterol synthesis, the destiny of cholesterol from low-density lipoprotein and the transport of cholesterol between the plasma membrane and the endoplasmic reticulum. Protein levels and gene expression of the main proteins involved in cholesterol homeostasis were analysed by western blotting and RT-PCR, respectively. HepG2 cells exposed to hexadecylphosphocholine showed an increase in cholesterol biosynthesis when acetate, but not mevalonate, was used as a substrate. The activity of 3-hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.34) and low-density lipoprotein receptor, as well as the corresponding mRNA expression, increased after 24 h of treatment with hexadecylphosphocholine. Cholesteryl linoleate in low-density lipoprotein uptake and further hydrolysis of these esters increased but the cholesterol esterification was reduced after 6 h of treatment with alkylphosphocholine. Cholesterol transport from the plasma membrane to the endoplasmic reticulum was impaired by hexadecylphosphocholine. In conclusion, hexadecylphosphocholine interfered with the transport of cholesterol from the cell surface to the endoplasmic reticulum, leading to a depletion of cholesterol in the endoplasmic reticulum and a deregulation of cholesterol biosynthesis. The accumulation of cholesterol within the cell and the reduction in phosphatidylcholine synthesis produces an alteration in the phosphatidylcholine/cholesterol ratio that may well be responsible for the antiproliferative activity exhibited by hexadecylphosphocholine in HepG2 cells.