Evidence against an abstraction or direct insertion mechanism for cytochrome P-450 catalysed meta hydroxylations

Warfarin, specifically labeled with deuterium in the 7 position, was incubated with liver microsomes from untreated rats or rats which were pretreated with either phenobarbital of β-napthoflavone. The four phenolic metabolites (6-, 7-, 8- and 4′-hydroxywarfarin) were isolated and quantitated by $\text{GC}\text{MS}$ and the percent deuterium retention calculated. In all induction states the 7-hydroxy metabolite of (7,²H)warfarin retained greater than 77% of the deuterium. These results suggest that hydroxylation at the 7 position (meta hydroxylation) cannot proceed by either a direct insertion or abstraction mechanism.     

Gene discovery and microarray analysis of cacao (Theobroma cacao L.) varieties

The cacao bean harvest from the relatively under developed tropical tree cacao (Theobroma cacao L.) is subject to high losses in potential production due to pests and diseases. To discover and understand the stability of putative natural resistance mechanisms in this commodity crop, essential for chocolate production, we undertook a gene-discovery program and demonstrated its use in gene-expression arrays. Sequencing and assembling bean and leaf cDNA library inserts produced a unique contig set of 1,380 members. High-quality annotation of this gene set using Blast and MetaFam produced annotation for 75% of the contigs and allowed us to identify the types of gene expressed in cacao beans and leaves. Microarrays were constructed using amplified inserts of the uni-gene set and challenged with bean and leaf RNA from five cacao varieties. The microarray performed well across the five randomly chosen cacao genotypes and did not show a bias towards either leaf or bean tissues. This demonstrates that the gene sequences are useful for microarray analysis across cacao genotypes and tissue types. The array results, when compared with real-time PCR results for selected genes, showed a correlation with differential gene-expression patterns.We intend that the resultant DNA sequences and molecular microarray platform will help the cacao community to understand the basis, likely stability and pathotype resistance range of candidate cacao plants.     

Functional expression of murine V2R pheromone receptors involves selective association with the M10 and M1 families of MHC class Ib molecules

The vomeronasal organ (VNO) of the mouse has two neuronal compartments expressing distinct families of pheromone receptors, the V1Rs and the V2Rs. We report here that two families of major histocompatibility complex (MHC) class Ib molecules, the M10 and the M1 families, show restricted expression in V2R-expressing neurons. Our data suggest that neurons expressing a given V2R specifically co-express one or a few members of the M10 family. Biochemical and immunocytochemical analysis demonstrates that in VNO sensory dendrites M10s belong to large multi-molecular complexes that include pheromone receptors and beta2-microglobulin (beta2m). In cultured cells, M10s appear to function as escort molecules in transport of V2Rs to the cell surface. Accordingly, beta2m-deficient mice exhibit mislocalization of V2Rs in the VNO and a specific defect in male-male aggressive behavior. The functional characterization of M10 highlights an unexpected role for MHC molecules in pheromone detection by mammalian VNO neurons.     

Predicting fine‐scale distributions of peripheral aquatic species in headwater streams

Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. We predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistance and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients.     

Female reproductive parameters in the Javan gibbon (Hylobates moloch)

Javan gibbons (Hylobates moloch) are one of the most endangered gibbon species in the world. Data on the reproductive biology of the species are almost nonexistent, and a general understanding of the female reproductive biology of this species is important for both ex situ and in situ conservation. Using 18 years of data from 11 captive individuals, we provide new information on the reproductive biology of Javan gibbons based on sexual swelling and menstrual bleeding, including reproductive development, interbirth intervals, and ovarian cycle lengths. Menarche and the onset of sexual swelling occurred at 6.2 and 6.5 years respectively, followed by a period of adolescent sterility of about 1.5 years. Average age at first birth was 8.8 years, and interbirth intervals were about 2.3 years, decreasing to 1.0 year during cases of infant mortality at or shortly after birth. Ovarian cyclicity was measured through periods between menstrual bleeding and sexual swelling. Menstrual bleeding indicates the start of a new ovarian cycle, while sexual swelling normally occurs near the time of ovulation. Menstrual bleeding intervals gave a cycle length of 25.6 days, while sexual swelling intervals gave a cycle length of 27.3 days. These both correspond closely to cycle lengths in other gibbon species, as well as hormonal studies in Javan gibbons. In particular, observing the presence/absence of swellings was found to be a useful and easy method to monitor female ovarian cycles, and could be a practical noninvasive technique for caretakers and researchers. Zoo Biol 29:449–456, 2010. © 2009 Wiley‐Liss, Inc.