Modulation of porcine biotransformation enzymes by anthelmintic therapy with fenbendazole and flubendazole

Fenbendazole (FEN) and flubendazole (FLU) are benzimidazole anthelmintics often used in pig management for the control of nematodoses. The in vivo study presented here was designed to test the influence of FLU and FEN on cytochrome P4501A and other cytochrome P450 (CYP) isoforms, UDP-glucuronosyl transferase and several carbonyl reducing enzymes. The results indicated that FEN (in a single therapeutic dose as well as in repeated therapeutic doses) caused significant induction of pig CYP1A, while FLU did not show an inductive effect towards this isoform. Some of the other hepatic and intestinal biotransformation enzymes that were assayed were moderately influenced by FEN or FLU. Strong CYP1A induction following FEN therapy in pigs may negatively affect the efficacy and pharmacokinetics of FEN itself or other simultaneously or consecutively administered drugs. From the perspective of biotransformation enzyme modulation, FLU would appear to be a more convenient anthelmintic therapy of pigs than FEN.     

Yeasts and algae isolated from cows with mastitis in the south-eastern part of Poland

The aim of the study was to evaluate the occurrence of mycotic and protohecal mastitis in herds in south-eastern part of Poland. A total of 3091 milk samples from udder quarters with clinical and subclinical mastitis from 29 dairy herds was investigated in this survey. Milk samples were plated as soon as possible on blood agar (BA), Mac Conkey agar, aesculin-tallium acetate-crystal violet agar, and Sabouraud agar. A hundred and thirty one yeast (4.23%) and eleven Protoheca zopfii (0.35%) strains were isolated from cows with clinical and subclinical mastitis. All the isolated fungi were the yeast classified into 4 genera (Candida, Trichosporon, Saccharomyces and Rhodotorula). The most frequently isolated yeasts were Candida sp., C. kefyr, C. humicola, C. rugosa and C. inconspicua. Both fungi and algae were isolated first of all during a confinement-housing season.     

Septin-mediated plant cell invasion by the rice blast fungus, Magnaporthe oryzae

To cause rice blast disease, the fungus Magnaporthe oryzae develops a pressurized dome-shaped cell called an appressorium, which physically ruptures the leaf cuticle to gain entry to plant tissue. Here, we report that a toroidal F-actin network assembles in the appressorium by means of four septin guanosine triphosphatases, which polymerize into a dynamic, hetero-oligomeric ring. Septins scaffold F-actin, via the ezrin-radixin-moesin protein Tea1, and phosphatidylinositide interactions at the appressorium plasma membrane. The septin ring assembles in a Cdc42- and Chm1-dependent manner and forms a diffusion barrier to localize the inverse-bin-amphiphysin-RVS-domain protein Rvs167 and the Wiskott-Aldrich syndrome protein Las17 at the point of penetration. Septins thereby provide the cortical rigidity and membrane curvature necessary for protrusion of a rigid penetration peg to breach the leaf surface.     

Assessment of Genetic Diversity of Drought Tolerant and Susceptible Rice Genotypes Using Microsatellite Markers

The introgression of wild chromosomal segments into popular rice varieties is one of the potential approaches for developing varieties for drought stress condition. Sixteen genotypes, including nine indica, two tropical japonica and five chromosome segments substitution lines(CSSLs) with different levels of tolerance/susceptibility to drought stress, were selected for diversity study. Sixty-three microsatellite markers were utilized for assessing genetic diversity. A total of 95 alleles were amplified, and out of them, 60 were polymorphic. Six unique alleles, amplified by the microsatellite loci RM276, RM472,RM488, RM537, RM541 and RM28089, were identified in six genotypes, namely FR13A, Brahamanakhi,RUF44, Swarna-sub1, Brahamanakhi and Satyabhama. The highest genetic similarity was found among CSSLs. Polymorphism information content(PIC) value varied from 0 to 1.00 with an average of 0.66 per locus. Twenty-eight microsatellites were found to be polymorphic, which could be used in marker-assisted selection programme. All the sixteen genotypes were grouped into two major clusters at genetic similarity of 0.64. In the cluster I, five CSSLs identified as diverse genotypes had wild ancestor segments responsible for drought tolerance, and hence they could be utilized as potential donors. The popular Indian varieties, Swarna-sub1 and IR64-sub1, could be used as recurrent parents in the future breeding program for developing varieties for abiotic stresses such as submergence and drought.     

Phenotypic plasticity in the morphology of small benthic Icelandic Arctic charr (Salvelinus alpinus)

Intraspecific phenotypic diversity is the raw material for evolution, so understanding its origin and maintenance is critically important for conservation of biodiversity. Intraspecific diversity in a trait or a suite of traits can result from genetic diversity and/or phenotypic plasticity. The two are, however, not independent as plasticity has been shown to evolve. In this study, we evaluated the importance of phenotypic plasticity in generating morphological diversity in populations of small benthic Arctic charr in Iceland, using a rearing experiment with contrasting modes of feeding. We also examined the association between phenotypic plasticity in offspring groups generated by the contrasting feeding modes and important ecological variables characterising the natural habitats of the respective populations. Although the level of plasticity could not be related to any of the ecological measurements, clear differences in morphological reaction norms among populations suggest that plasticity is an important aspect of morphological diversity of the charr. It is not clear whether that plasticity is adaptive, but it is notable that reaction norms in all populations have similar reaction to the treatments.     

Biotransformation of flubendazole and selected model xenobiotics in Haemonchus contortus

Haemonchus contortus is one of the most pathogenic parasites of small ruminants (e.g., sheep and goat). The treatment of haemonchosis is complicated because of frequent resistance of H. contortus to common anthelmintics. The development of resistance can be facilitated by the action of drug metabolizing enzymes of parasites that can deactivate anthelmintics and thus protect parasites against the toxic effect of the drug. The aim of this project was to investigate the Phase I biotransformation of benzimidazole anthelmintic flubendazole in H. contortus and to determine the biotransformation of other model xenobiotics. For this purpose, in vitro (subcellular fractions of H. contortus homogenate) as well as ex vivo (live nematodes cultivated in flasks with medium) experiments were used. The results showed that cytosolic NADPH-dependent enzymes of H. contortus metabolize flubendazole via reduction of its carbonyl group. The apparent kinetic parameters of this reaction were determined (V'max=39.8+/-2.1 nM min(-1), K'm=1.5+/-0.3 microM). The reduction of flubendazole in H. contortus is stereospecific, the ratio of (-):(+) enantiomers of reduced flubendazole formed was 90:10. Reduced flubendazole was the only Phase I metabolite found. Effective reduction of other xenobiotics with carbonyl group (metyrapon, daunorubicin, and oracin) was also found. Significant activity of carbonyl-reducing enzymes may be important for H. contortus to survive the attacks of anthelmintics or other xenobiotics with carbonyl group.     

Improvement of Tissue Survival of Skin Flaps by 5α-Reductase Inhibitors: Possible Involvement of Nitric Oxide and Inducible Nitric Oxide Synthase

Background:

Skin flap grafting is a popular approach for reconstruction of critical skin and underlying soft tissue injuries. In a previous study, we demonstrated the beneficial effects of two 5α-reductase inhibitors, azelaic acid and finasteride, on tissue survival in a rat model of skin flap grafting. In the current study, we investigated the involvement of nitric oxide and inducible nitric oxide synthase (iNOS) in graft survival mediated by these agents.

Methods:

A number of 42 male rats were randomly allocated into six groups: 1, normal saline topical application; 2, azelaic acid (100 mg/flap); 3, finasteride (1 mg/flap); 4, injection of L-N^G-nitroarginine methyl ester (L-NAME) (i.p., 20 mg/kg); 5, L-NAME (20 mg/kg, i.p.) + azelaic acid (100 mg/flap, topical); 6, L-NAME (20 mg/kg, i.p.) + finasteride (1 mg/flap, topical). Tissue survival, level of nitric oxide, and iNOS expression in groups were measured.

Results:

Our data revealed that azelaic acid and finasteride significantly increased the expression of iNOS protein and nitric oxide (NO) levels in graft tissue (P < 0.05). These increases in iNOS expression and NO level were associated with higher survival of the graft tissue.

Conclusion:

It appears that alterations of the NO metabolism are implicated in the azelaic acid- and finasteride-mediated survival of the skin flaps.Key Words: Finasteride, Azelaic acid, Surgical flaps, Nitric oxide, Nitric oxide synthase Type II     

Phase I biotransformation of albendazole in lancet fluke (Dicrocoelium dendriticum)

Dicroceliosis, a lancet fluke infection, is a frequent parasitosis of small ruminants and the anthelmintic drug albendazole (ABZ) is effective in control of this parasitosis. The aim of our project was to study the metabolism of ABZ and ABZ sulphoxide (ABZ.SO) in lancet fluke. Both invitro (subcellular fractions of fluke homogenates) and exvivo experiments (adult flukes cultivated in medium) were performed for this purpose. ABZ was metabolised invitro by lancet fluke NADPH-dependent enzymes by two oxidative steps (sulphoxidation and sulphonation). The apparent kinetic parameters of these reactions have been determined. In the exvivo experiments, only ABZ sulphoxidation was observed. The stereospecificity in ABZ sulphoxidation invitro was slight, with preferential formation of (+)-ABZ.SO enantiomer. In contrast (−)-ABZ.SO formation predominated in exvivo experiments. Sulphoreduction of ABZ.SO occurred neither invivo nor exvivo. The detection of ABZ oxidative metabolites indicates the presence of drug metabolising oxidases in lancet fluke.     

Optimization of Heat Processing of Farmed Atlantic Cod (Gadus morhua) Muscle with Respect to Cook Loss,Water Holding Capacity,Color, and Texture

Convenience products of fish that are heat processed in-pack are often subjected to a compromise between quality and durability within the framework of required safety. The purpose of this study was to provide knowledge for optimizing pasteurization of cod muscle by quantifying changes in water holding capacity (WHC), cook loss, color, and texture within a wide range of processing times and temperatures. A heat load equivalent to 2 min at 70°C may be applied to the cod while maintaining the WHC above 66%, the cook loss below 5.6%, and keeping hardness and whiteness low, provided that the processing temperature is kept in the range 68 ± 4°C.