Comparative sequence analysis and radiation hybrid mapping of the canine keratin 10 gene

The type I keratin, K10, is expressed in epidermal keratinocytes undergoing terminal differentiation to form the stratum corneum, a barrier essential for life. In order to facilitate the study of keratinization disorders in the dog, the sequence and mapping of KRT10 is reported. The coding region of KRT10 is 1707 bp and is comprised of eight exons. Although the length of KRT10 has been reported to be polymorphic in humans, this was not observed in the eight domestic dog breeds studied, although one wild canid displayed a size difference. The structure and sequence of this gene is highly conserved across mammalian species. Canine K10 had an 86% amino acid identity with the human gene. KRT10 was localized to the on-going canine radiation hybrid map to chromosome 9 in the type I keratin gene cluster.

Current and noise in a model of an alternating current scanning tunneling microscope molecule-metal junction

The transport properties of a simple model for a finite level structure (a molecule or a dot) connected to metal electrodes in an alternating current scanning tunneling microscope (ac-STM) configuration is studied. The finite level structure is assumed to have strong binding properties with the metallic substrate, and the bias between the STM tip and the hybrid metal-molecule interface has both an ac and a dc component. The finite frequency current response and the zero-frequency photoassisted shot noise are computed using the Keldysh technique, and examples for a single-site molecule (a quantum dot) and for a two-site molecule are examined. The model may be useful for the interpretation of recent experiments using an ac-STM for the study of both conducting and insulating surfaces, where the third harmonic component of the current is measured. The zero-frequency photoassisted shot noise serves as a useful diagnosis for analyzing the energy level structure of the molecule. The present work motivates the need for further analysis of current fluctuations in electronic molecular transport.

Comparative sequence analysis and radiation hybrid mapping of two epidermal type II keratin genes in the dog: keratin 1 and keratin 2e

In order to extend knowledge of the process of cornification across species and to be better able to recognize inborn errors in keratin synthesis in the dog, we describe the organization and chromosome mapping of canine KRT1 and KRT2E and compare these results to human and murine sequence data. The coding regions of KRT1 and KRT2E are 1,860 bp and 1,902 bp respectively, distributed over nine exons. Both genes are localized on the canine radiation hybrid map to chromosome 27 in the type II keratin gene cluster close to polymorphic markers. These genes are highly conserved across species and based on both genomic and amino acid sequences, canine KRT1 and KRT2E share greater homology with humans than with mice.

Detailed four-way comparative mapping and gene order analysis of the canine ctvm locus reveals evolutionary chromosome rearrangements

Canine tricuspid valve malformation (CTVM) maps to canine chromosome 9 (CFA9), in a region syntenic with gene-dense human chromosome 17q. To define synteny blocks, we analyzed 148 markers on CFA9 using radiation hybrid mapping and established a four-way comparative map for human, mouse, rat, and dog. We identified a large number of rearrangements, allowing us to reconstruct the evolutionary history of individual synteny blocks and large chromosomal segments. A most parsimonious rearrangement scenario for all four species reveals that human chromosome 17q differs from CFA9 and the syntenic rodent chromosomes through two macroreversals of 9.2 and 23 Mb. Compared to a recovered ancestral gene order, CFA9 has undergone 11 reversals of <3 Mb and 2 reversals of >3 Mb. Interspecies reuse of breakpoints for micro- and macrorearrangements was observed. Gene order and content of the ctvm interval are best extrapolated from murine data, showing that multispecies genome rearrangement scenarios contribute to identifying gene content in canine mapping studies.

Identification of isoforms and RH mapping of canine KIT

The proto-oncogene, C-KIT (KIT), encodes a tyrosine kinase receptor, and mutations in this gene are causative for several mammalian diseases, including cancer and a form of pigmentation-associated hereditary deafness. Our laboratories are interested in a form of hereditary deafness that is associated with abnormalities in pigmentation and is common in the Dalmatian. Thus, KIT is being analyzed as a candidate gene for deafness in this breed. In addition to our interest in deafness, we are involved in mapping gene loci in the canine genome. Reported here is the identification of two isoforms of canine C-kit and radiation hybrid mapping of KIT to CFA13.

Comparison of MultiMap and TSP/CONCORDE for constructing radiation hybrid maps

Radiation hybrid (RH) map construction allows investigators to locate both type I and type II markers on a given genome map. The process is composed of two steps. The first consists of determining the pattern distribution of a set of markers within the different cell lines of an RH panel. This is mainly done by polymerase chain reaction (PCR) amplification and gel electrophoresis, and results in a series of numbers indicating the presence or the absence of each marker in each cell line. The second step consists of a comparison of these numbers, using various algorithms, to group and then order markers. Because different algorithms may provide (slightly) different orders, we have compared the merits of the MultiMap and TSP/CONCORDE packages using a data set of information currently under analysis for construction of the canine genome RH map.

Hazard analysis of Escherichia coli O157:H7 contamination during beef slaughtering in Calvados, France

To identify hazard points and critical points during beef slaughtering, which is a necessary first step toward developing a hazard analysis and critical control point system to control meat contamination by Escherichia coli O157:H7, samples (n = 192) from surfaces, work tops, worker's hands, and beef carcasses were collected from a slaughterhouse in Calvados, France. Five strains of E. coli O157:H7 were isolated from a footbridge and a worker's apron at the preevisceration post and from a worker's hand at the defatting post. Three isolates carried stx2c, eae, and EHEC-hlyA genes and showed similar molecular types by random amplified polymorphic DNA, polymerase chain reaction IS3, and XbaI pulsed-field gel electrophoresis. Thus, this study has shown that preevisceration and defatting post and associated worker's materials are critical points for carcasses contamination by E. coli O157:H7 during beef slaughtering.

Procyanidin Production by Fagopyrum esculentum Callus Culture

FAGOPYRUM ESCULENTUM CALLUS cultures grown on B5 medium synthesize procyanidins B2 (0.6-1.8 mg/g dry wt) and B2-3'- O-gallate (3.5-6.0 mg/g dry wt). Sucrose is a better source than other carbohydrates and moderate concentrations (3-4%) stimulate both growth and procyanidin synthesis. While darkness was not a limiting factor, light induced faster growth and increased procyanidin contents. Treatment with gallic acid strongly stimulated the procyanidin B2-3'- O-gallate production, but drastically inhibited growth, leading to a two-step-culture experiment combining convenient growth and increased galloylated dimer synthesis (up to 45 mg/g dry wt).