A modified fluorometric method to quantify the concentration effect (pI50) of photosystem II-inhibiting herbicides

Chlorophyll fluorescence induction curves of isolated thylakoids were measured in the absence and in the presence of various concentrations of photosystem II-inhibiting herbicides. A mathematical program was applied to simulate the curves. Based on these simulated curves a new method is developed to determine the concentration effect (pI₅₀) of the herbicides. The results of the new method correspond well with reported values in the literature. The method is very convenient and time-saving.     

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.     

Strong antiviral activity of heated and hydrated dolomite--preliminary investigation

Heated and hydrated naturally occurring dolomite showed very strong antiviral activity. Infectivity of avian and human influenza, avian infectious bronchitis (coronavirus), Newcastle disease (paramyxovirus) and avian laryngotracheitis (herpesvirus) viruses dropped at least 1,000 fold following contact with the dolomite for five minutes at 4 degrees C. Dolomite is expected to be useful to inhibit the incidence of emerging and re-emerging infectious diseases.     

Identification of ommastrephid squid paralarvae collected in northern Hawaiian waters and phylogenetic implications for the family Ommastrephidae using mtDNA analysis

ABSTRACT:   A total of 110 adult individuals from four ommastrephid (family Ommastrephidae) squid species ( Ommastrephes bartramii, Sthenoteuthis oualaniensis, Eucleoteuthis luminosa, and Hyaloteuthis pelagica ) were used to obtain diagnostic DNA markers for species identification. Restriction fragment length polymorphism (RFLP) analysis of a partial segment (855 bp) of the mitochondrial DNA cytochrome oxidase I (COI) gene amplified by polymerase chain reaction (PCR) revealed that the restriction profiles of two endonucleases ( Alu  I and Tsp 509 I) were diagnostic for species identification. The restriction assay partially supplemented with nucleotide sequence analysis successfully assigned 69 damaged and morphologically equivocal ommastrephid paralarvae collected in northern Hawaiian waters, identifying 60 O. bartramii , eight S. oualaniensis , and one E. luminosa . The family Ommastrephidae appears to be monophyletic. Although the phylogenetic relationships among genera were not resolved well due to apparent homoplasy and large genetic divergence between species, COI sequence data without transitions provided support for subfamily level relationships.     

Stereoselectivity of the generation of 3-mercaptohexanal and 3-mercaptohexanol by lipase-catalyzed hydrolysis of 3-acetylthioesters

The enantioselectivity of the generation of 3-mercaptohexanal and 3-mercaptohexanol, two potent sulfur-containing aroma compounds, by lipase-catalyzed hydrolysis of the corresponding 3-acetylthioesters was investigated. The stereochemical course of the kinetic resolutions was followed by capillary gas chromatography using modified cyclodextrins as chiral stationary phases. The enzyme preparations tested varied significantly in terms of activity and enantioselectivity (E). The highest E value (E = 36) was observed for the hydrolysis of 3-acetylthiohexanal catalyzed by lipase B from Candida antarctica resulting in (S)-configured thiol products. Immobilization of the enzyme (E = 85) and the use of tert-butyl alcohol as cosolvent (E = 49) improved the enantioselectivity. Modification of the acyl moiety of the substrate (3-benzoylthiohexanal) had no significant impact. The sulfur-containing compounds investigated possess attractive odor properties, and only one of the enantiomers exhibits the pleasant citrus type note.     

Regional differences of pheromone production in the sebaceous glands of castrated goats treated with testosterone

The primer pheromone is responsible for the "male effects" in goats and produced in the sebaceous glands testosterone-dependently. In the present study, the responses of sebaceous glands obtained from the head and rump regions of castrated goats were examined by our bioassay system after testosterone treatment to demonstrate the presence of regional differences in the pheromone production in male goats. The testosterone treatment resulted in the marked development of sebaceous glands and the induction of pheromone bioactivity in the head region of the goats. On the contrary, this treatment brought neither development of the sebaceous glands nor induction of pheromone bioactivity in the rump region. The treatment increased immunoreactivities to androgen receptors (AR) and 5alpha-reductase in the sebaceous glands of both regions, although the activities were more apparent in the head region than the rump region. These findings suggest that the primer pheromone of male goats is produced specifically in the sebaceous glands of the head region due partly to regional differences in the expression of AR and 5alpha-reductase mediating testosterone bioactivities.     

Liquid chromatography-tandem mass spectrometry analysis of 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine in cooked meats

Several cooked meats such as beef (fried, coated-fried), pork (fried, coated-fried), and chicken (fried, griddled, coated-fried, roasted) were analyzed for the heterocyclic amine 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5- b]pyridine (4'-OH-PhIP) not commonly determined in food and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). The highest content of 4'-OH-PhIP was found in fried and griddled chicken breast, the concentration being 43.7 and 13.4 ng/g, respectively, whereas the corresponding PhIP concentrations were 19.2 and 5.8 ng/g. The estimated concentration of both pyridines in fried pork loin, in fried pork sausages, and in coated-fried chicken was below 2.5 ng/g. In the rest of the samples, 4'-OH-PhIP was not detected. The analyses were performed by solid-phase extraction and LC-MS/MS. The fragmentation of 4'-OH-PhIP in an ion trap mass analyzer was studied in order to provide information for the identification of 4'-OH-PhIP. Additionally, the effect of red wine marinades on the formation of 4'-OH-PhIP in fried chicken was examined, finding a notable reduction (69%) in the amine's occurrence.