AGHR polymorphism and its associations with carcass traits in Harrwoo cattle

The growth hormone receptor (GHR) is a membrane transmitter for the growth hormone signal transduction pathway that regulates various metabolic activities, including cell growth and expressions of cytokine genes. The presence or absence of a genetic polymorphism for the LINE-1 retroposon in the PI promoter, which specifically regulates theGHR gene expression in the liver, was screened by a novel detection method and examined for its relationships with carcass traits in Hanwoo cattle. Han woo cattle had taurine type LINE-1 present (alleleI) as well as incidine type LINE-1 absent (alleleA) promoter sequences. Three genotypes,I/I, I/A andA/A, showed frequencies of 49.1, 36.7 and 14.2%, respectively. The effects of allele A were significant on mean differences for final weight, eye muscle area, marbling score and fat color (p<0.05), but not for carcass weight, backfat thickness, final meat quality grade or meat color (p>0.05). Most 30-month old Hanwoo steers bearing the LINE-1 absent promoter had whiter fat color, heavier live weight and higher marbling score, reflecting intramuscular fat deposition inM. longissimus dorsi, compared to animals bearing a LINE-1 present promoter. This suggests that aGHR polymorphism could be a potential genetic marker for improving beef production of Hanwoo cattle.     

First Passage Time Analysis of Animal Movement and Insights into the Functional Response

Movement plays a role in structuring the interactions between individuals, their environment, and other species. Although movement models coupled with empirical data are widely used to study animal distribution, they have seldom been used to study search time. This paper proposes first passage time as a novel approach for understanding the effect of the landscape on animal movement and search time. In the context of animal movement, first passage time is the time taken for an animal to reach a specified site for the first time. We synthesize current first passage time theory and derive a general first passage time equation for animal movement. This equation is related to the Fokker–Planck equation, which is used to describe the distribution of animals in the landscape. We illustrate the first passage time method by analyzing the effect of territorial behavior on the time required for a red fox to locate prey throughout its home range. Using first passage time to compute search times, we consider the effect of two different searching modes on a functional response. We show that random searching leads to a Holling type III functional response. First passage time analysis provides a new tool for studying how animal movement may influence ecological processes.     

NUTRIENT EFFECTS ON SEAGRASS EPIPHYTE COMMUNITY STRUCTURE IN FLORIDA BAY1

A field experiment was employed in Florida Bay investigating the response of seagrass epiphyte communities to nitrogen (N) and phosphorus (P) additions. While most of the variability in epiphyte community structure was related to uncontrolled temporal and spatial environmental heterogeneity, P additions increased the relative abundance of the red algae–cyanobacterial complex and green algae, with a concomitant decrease in diatoms. When N was added along with P, the observed changes to the diatoms and the red algae–cyanobacterial complex were in the same direction as P‐only treatments, but the responses were decreased in magnitude. Within the diatom community, species relative abundances, species richness, and diversity responded weakly to nutrient addition. P additions produced changes in diatom community structure that were limited to summer and were stronger in eastern Florida Bay than in the western bay. These changes were consistent with well‐established temporal and spatial patterns of P limitation. Despite the significant change in community structure resulting from P addition, diatom communities from the same site and time, regardless of nutrient treatment, remained more similar to one another than to the diatom communities subject to identical nutrient treatments from different sites and times. Overall, epiphyte communities exhibited responses to P addition that were most evident at the division level.     

Delivery of Human Immunodeficiency Virus Vaccine Vectors to the Intestine Induces Enhanced Mucosal Cellular Immunity

Effective vaccines for human immunodeficiency virus type 1 (HIV-1) will likely need to stimulate protective immunity in the intestinal mucosa, where HIV-1 infection causes severe CD4⁺ T-cell depletion. While replication-competent recombinant adenovirus (rAd) vectors can stimulate adenovirus-specific mucosal immunity after replication, oral delivery of replication-defective rAd vectors encoding specific immunogens has proven challenging. In this study, we have systematically identified barriers to effective gut delivery of rAd vectors and identified sites and strategies to induce potent cellular and humoral immunity. Vector-mediated gene transfer by rAd5 was susceptible to low-pH buffer, gastric and pancreatic proteases, and extracellular mucins. Using ex vivo organ explants, we found that transduction with rAd5 was highest in the ileum and colon among all intestinal segments. Transgene expression was 100-fold higher after direct surgical introduction into the ileum than after oral gavage, with rAd5 showing greater potency than the rAd35 or the rAd41 vector. A single immunization of rAd5 encoding HIV-1 gp140B to the ileum stimulated potent CD8⁺ T-cell responses in the intestinal and systemic compartments, and these responses were further enhanced by intramuscular rAd5 boosting. These studies suggest that induction of primary immune responses by rAd5 gut immunization and subsequent systemic boosting elicits potent antigen-specific gut mucosal responses.Human immunodeficiency virus type 1 (HIV-1) infection is characterized by uncontrolled virus replication and cytopathicity in the intestinal mucosa, the site of major T-cell depletion after primary infection. The gastrointestinal (GI) tract is the predominant site of a pronounced CD4⁺ T-cell loss in the early stages of HIV infection and simian immunodeficiency virus (SIV) infection in the nonhuman primate model (3, 23, 26, 43). It has been suggested that a mucosal vaccine which generates HIV-specific CD8⁺ T cells in the gut could prevent the loss of CD4⁺ cells in gut-associated lymphoid tissue, establishment of infection, or spread of virus (13, 34). Therefore, targeted delivery of vaccines to the GI tract to stimulate mucosal responses has the potential to improve the efficacy of immune protection against HIV-1; however, the site of gene-based transduction and the barriers to vaccine delivery have not been well defined.Adenoviruses (Ads) have been used extensively as vectors for both gene transfer and vaccine development. They offer several advantages as tools for vaccine delivery, such as the ability to transduce both dividing and nondividing cells, relative safety and stability in vivo, ease of production in high titers, and lack of integration (2, 35). These vectors are promising because parenteral administration in both animals and humans has been shown to generate strong and long-lasting humoral and cellular immune responses. The immune responses surpass those achieved with other types of gene vectors and genetic vaccines (5, 38, 46). As a result, recombinant Ad (rAd) vectors have been developed and tested as vaccine vehicles to immunize against a number of pathogens (4, 10, 15, 18, 41).Orally (p.o.) delivered vaccines are attractive in theory because of their ease of administration and potential to deliver antigen to gut-associated lymphoid tissue, permitting induction of immune responses in both mucosal and systemic compartments. At the same time, p.o. delivery of replication-defective rAd vectors has posed a challenge and has met with variable levels of success. Immunization with rAd5 encoding rabies virus antigens, influenza virus antigens, or other antigens has generated some protection against infection in animal models (9, 27, 31, 39, 41), but p.o. immunization has elicited much lower CD8⁺ T-cell responses than systemic delivery (33), and a much higher dose is required to induce immune responses (37). We have recently shown in an HIV vaccine model that rAd41, a human enteric Ad-based vector, induced potent CD8⁺ T-cell responses in both systemic and mucosal compartments when primed p.o. or in the ileum (17). The previous study showed that rAd41 vectors delivered through direct ileal injection elicited mucosal cell immunity, but whether other rAd vectors could stimulate these responses and which factors affected delivery and immunogenicity were unknown. In this report, we have investigated the mechanisms associated with the low immunogenicity of rAd5 dosed through the p.o. route in mice. The purpose was to identify barriers to effective delivery of rAd vectors to gut tissues and to ascertain sites and strategies for induction of potent cellular and humoral immunity. To investigate the mechanism of the low immunogenicity of rAd vectors through the p.o. route and develop effective delivery of rAd5 and rare serotype rAd35 vectors as gut mucosal HIV vaccines, we have analyzed the obstacles to p.o. immunization, characterized vector transgene expression, and systematically compared immune responses induced by p.o. and local immunization strategies. These studies demonstrated that the higher immune responses were strongly associated with higher gene expression in the intestine and support further study of gut mucosal immunization in SIV challenge models as a potential HIV vaccine strategy.     

Free and bound state structures of 6-O-methyl homoerythromycins and epitope mapping of their interactions with ribosomes

The solution and solid state conformations of several 6-O-methyl homoerythromycins 1–4 were studied using a combination of X-ray crystallography, NMR spectroscopy and molecular modelling calculations. In the solid state 1 was found to exist as the two independent molecules with similar structures termed 3-endo-folded-out. In solution a significant conformational flexibility was noticed especially in the C2 to C5 region. The compounds 1 and 2 unlike 14-membered macrolides adopted the 3-endo-folded-out conformation while 3 and 4 existed in the classical folded-out conformation. TrNOESY and STD experiments showed that 1 and 2 bound to the Escherichia coli ribosome while 3 and 4, lacking the cladinose sugar, did not exhibit binding activities, this being in accordance with biochemical data. The bound conformations were found to be very similar to the free ones, some small differences were observed and discussed. The STD experiments provided evidence on binding epitopes. The structural parts of 1 and 2 in close contact with ribosome were similar, however the degree of saturation transfer was higher for 2. The differences between tr-NOE data and STD enhancements in 1 and 2 arouse as a consequence of structural changes upon binding and a closer proximity of 2 to the ribosome surface. An understanding of the molecular mechanisms involved in the interaction of macrolides with ribosomes can help in developing strategies aiming at design of potential inhibitors.     

Es-x/Ces1 prevents triacylglycerol accumulation in McArdle-RH7777 hepatocytes

Mouse esterase-x/carboxylesterase 1 (Es-x/Ces1) is a close homolog of triacylglycerol hydrolase/carboxylesterase 3 (TGH/Ces3). Es-x possesses a conserved esterase/lipase active site motif, suggesting that like TGH it could play a role in hepatic triacylglycerol (TG) metabolism. McArdle-RH7777 cells stably transfected with Es-x cDNA accumulated significantly less TG and had increased production of acid-soluble metabolites (an indicator of β-oxidation) during incubations with 0.4 mM oleic acid when compared to empty vector or TGH cDNA transfected cells. Reduction of cellular TG persisted in the presence of esterase/lipase inhibitor E600 indicating that Es-x-mediated TG lowering can be largely explained by reduced partitioning of exogenous fatty acids to TG and increased redirection to β-oxidation, rather than by increased TG turnover. Glycerol supplementation increased TG synthesis in both control and Es-x expressing cells to similar extent suggesting that Es-x expression did not reduce flux of metabolic intermediates through the glycerol-3-phosphate pathway. While Es-x expression reduced cellular TG levels, secretion of TG and apolipoprotein B remained unchanged when compared to control cells. Overall, these results suggest that Es-x limits hepatic TG accumulation by promoting β-oxidation.