Russian honey bee genotype identification through enhanced marker panel set.

Russian honey bees (RHB) are a breeding population developed by USDA-ARS as an effort to provide -resistant honey bees to beekeepers. The selection strategy for this breeding population was the first in honey bees to incorporate genetic stock identification (GSI). The original GSI approach has been in use for over a decade, and though effective, novel technologies and analytical approaches recently developed provide an opportunity for improvement.

Genetic Diversity and Structure in a Closed Breeding System of Russian Honey Bees.

High levels of genetic diversity are critical to the success of breeding programs. Russian honey bees are a selected stock that undergoes breeding in a closed block-based mating system. Given its established history, Russian stock has longitudinal measures of genetic integrity (i.

Differential Expression of Three Dopamine Receptors in Varroa-Resistant Honey Bees.

Various stocks of honey bees (Apis mellifera L. (Hymenoptera: Apidae)) employ multiple mechanisms to control varroa mite (Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae)) infestations. Identification of trait-associated genes and markers can improve efficiency of selective breeding.

Genome-wide patterns of differentiation within and among U.S. commercial honey bee stocks.

Background: The population genetics of U.S. honey bee stocks remain poorly characterized despite the agricultural importance of Apis mellifera as the major crop pollinator.

Population structure at two geographic scales in the burrowing crustacean Callichirus islagrande (Decapoda, Thalassinidea): historical and contemporary barriers to planktonic dispersal.

There has been much recent interest in the extent to which marine planktonic larvae connect local populations demographically and genetically. Uncertainties about the true extent of larval dispersal have impeded our understanding of the ecology and evolution of marine species as well as our attempts to effectively manage marine populations. Because direct measurements of larval movements are difficult, genetic markers have often been used for indirect measurements of gene flow among marine populations.

Purification, cDNA cloning, and characterization of ghrelin in channel catfish, Ictalurus punctatus.

The ghrelin peptide and cDNA encoding precursor protein were isolated from the stomach of a channel catfish, Ictalurus punctatus. Catfish ghrelin is a 22-amino acid peptide with a sequence of GSSFLSPTQKPQNRGDRKPPRV. The third serine residue has been modified by n-decanoic acid and unsaturated fatty acids; however, an octanoylated form could not be identified.

Response of toll-like receptors, lysozyme, and IGF-I in back-cross hybrid (F1 male (blue x channel) x female channel) catfish challenged with virulent Edwardsiella ictaluri.

Responses of toll-like receptors (TLR3 and TLR5), lysozyme, and insulin-like growth factor-I (IGF-I) to experimental challenge with virulent Edwardsiella ictaluri were measured in back-cross hybrid (F1 male (blue x channel) x female channel) catfish. The resistance levels to E. ictaluri and host response mechanisms of back-cross hybrids are unknown.

Differential gene expression of IGF-I, IGF-II, and toll-like receptors 3 and 5 during embryogenesis in hybrid (channel x blue) and channel catfish.

Insulin-like growth factors-I and-II (IGF-I and IGF-II) play important roles in growth and development of mammals. Toll-like receptors (TLRs) are pattern recognition molecules that orchestrate the induction of early innate immune response by recognition of specific sequences. Evidence is growing that suggests a relationship between growth and immune function.

Effects of cortisol and stress on channel catfish (Ictalurus punctatus) pathogen susceptibility and lysozyme activity following exposure to Edwardsiella ictaluri.

Periods of stress are often associated with disease outbreaks in cultured fish, and stress is often characterized by the secretion of cortisol. Although stress and cortisol secretion are highly correlated in fish, the role of cortisol in affecting channel catfish (Ictalurus punctatus) pathogen susceptibility is unclear. The effects of short-term stress and exogenous cortisol administration on channel catfish susceptibility to Edwardsiella ictaluri, the etiologic agent of enteric septicemia of catfish (ESC), were investigated.

Activation of TLR3 and TLR5 in channel catfish exposed to virulent Edwardsiella ictaluri.

Two toll-like receptors (TLR3 and TLR5) were identified from a catfish cDNA fry library based on sequence similarity to other vertebrate TLR genes. Expression (using real-time PCR) of TLR3 and TLR5 was measured for two strains of channel catfish in previously non-exposed fish 2, 5, 8, and 21 days after experimental Edwardsiella ictaluri challenge to determine if TLRs are associated with host response to E. ictaluri infection.

IGF-I and IGF-II mRNA expression in slow and fast growing families of USDA103 channel catfish (Ictalurus punctatus).

The objective of this study was to examine insulin-like growth factor (IGF)-I and IGF-II mRNA levels in fast and slow growing families of catfish. Relative levels of IGF-I and IGF-II mRNA were determined by real-time PCR. Family A exhibited a specific growth rate (SGR) of 3.

Complete sequence and characterization of the channel catfish mitochondrial genome.

In order to support analysis of channel catfish populations and genetic improvement programs, the channel catfish, Ictalurus punctatus, mitochondrial genome was completely sequenced and revealed gene structure and gene order common to vertebrates. Nucleotide sequence comparisons of cytochrome b (Cytb) and cytochrome c oxidase subunit 1 (COI) demonstrated genetic separation of the genera Ictalurus, Pylodictis and Ameiurus consistent with the taxonomic classification within Ictaluridae. The ictalurid Cytb nucleotide sequences were significantly different from a putative channel catfish Cytb sequence in GenBank.