Trichinella spiralis: macrophage activity and antibody response in chronic murine infection

The role of macrophages, their products, and the specific antibody response were examined during chronic Trichinella spiralis infection in BALB/c mice. Adult T. spiralis in intestines were detected from 5 to 20 dpi. Muscle larvae numbers peaked at 45 dpi and thereafter a reduction was noted. The highest numbers of macrophages in the peritoneal cavity of infected mice were obtained up to 30 dpi. The production of NO by macrophages in infected mice was suppressed at 5 dpi, and then NO release increased until 45 dpi. The levels of NO in plasma and urine were lower in infected mice during the entire experiment in comparison to control. The production of O(2)(-) in peritoneal macrophages was inhibited during the first two weeks after infection and then increased until 90 dpi. Circulating T. spiralis antigens in plasma and urine were detected from 5 to 30 dpi. Specific IgM and IgA in serum increased until 20 dpi. IgG, IgG(1), and IgG(2) levels in serum increased until 60 dpi.     

Study of interaction between calcium and zinc ond-galactose intestinal transport

Zinc is an essential trace element necessary to life. This metal may exert some of its physiological effects by acting directly on cellular membranes, either by altering permeability or by modulating the activity of membrane-bound enzymes. On the other hand, calcium is an essential element in a wide variety of cellular activities. The aim of the present work was to study a possible interaction between zinc and calcium on intestinal transport ofd-galactose in jejunum of rabbit in vitro. In media with Ca²⁺, when ZnCl₂ was present at 0.5 or 1 mM, zinc was found to reduce thed-galactose absorption significantly. In Ca²⁺-free media, where CaCl₂ was omitted and replaced isotonically with choline chloride, the sugar transport was not modified by zinc. Verapamil at 10⁻⁶ M (blocking mainly Ca²⁺ transport) did not modify the inhibitory effect of zinc ond-galactose transport. When 10⁻⁶ M of A 23187 (Ca²⁺-specific ionophore) was added with/without Ca²⁺ to the media, ZnCl₂ produced no change in sugar transport. These results could suggest a possible interaction of calcium and zinc for the same chemical groups of membrane, which could affect the intestinal absorption of sugars.     

Assessment of hydroxypropyl methylcellulose, propylene glycol, polysorbate 80, and hydroxypropyl-β-cyclodextrin for use in developmental and reproductive toxicology studies

BACKGROUND: A series of studies were conducted to assess Polysorbate 80 (PS80), Propylene Glycol (PG), and Hydroxypropyl‐β‐Cyclodextrin (HPβCD), when compared with Hydroxypropyl Methylcellulose (MC) in developmental and reproductive toxicology (DART) studies. METHODS: In the rat fertility study, 20 mg/kg MC, 10 mg/kg PS80, 1,000 mg/kg PG, 500 mg/kg HPβCD or 1,000 mg/kg HPβCD were administered orally before/during mating, and on gestation Day (GD) 0–7, followed by an assessment of embryonic development on GD 14. In the rat and rabbit teratology studies, the doses of MC, PS80, PG, and HPβCD were the same as those in the fertility study. In these teratology studies, pregnant females were dosed during the period of organogenesis, followed by an assessment of fetal external, visceral, and skeletal development. RESULTS: In the rat fertility and rat teratology studies, PS80, PG, and HPβCD did not exhibit toxicity, when compared with MC. Similarly, in the rabbit teratology study, there was no PS80 or PG‐related toxicity, when compared with MC. However, individual rabbits in the 500 and 1,000 mg/kg HPβCD groups exhibited maternal toxicity, which included stool findings, decreased food consumption, and body weight gain. Furthermore, one rabbit each in the 500 and 1,000 mg/kg HPβCD groups exhibited evidence of abortion, which was considered secondary to maternal toxicity. CONCLUSIONS: Although HPβCD was not well tolerated in rabbits at doses of 500 and 1,000 mg/kg, PS80 and PG were comparable to MC and should be considered for use in developmental and reproductive toxicology studies. Birth Defects Res (Part B) 89:504–516,2010. © 2010 Wiley‐Liss, Inc.     

Demonstration of growth in porcine thyroid cell culture

Eagle's minimum essential medium supplemented with 20 per cent newborn calf serum (N.C.S.) allows porcine thyroid cell survival but not cell growth in vitro. In NCTC 109 medium supplemented with 20 per cent N.C.S. these cells actively grow and may be serially propagated. Cell population doubling time expressed as DNA doubling value is 3.5 days at 37 degrees C in 95 per cent air-5 per cent CO2. Thyrotropin does not affect porcine thyroid cell multiplication in vitro but stimulates the plating efficiency in primary cultures to about 130 per cent of controls. Cell selection was obtained by replacing media with Earle's balanced salt solution. This operation provoked death of nearly all cells by day 18 but subsequent addition of growth medium resulted in proliferation of epithelial cell clones. From generation 2 to generation 8, cells produce thyroglobulin but they do not actively trap iodide nor form follicles when thyrotropin is added to the media. Cell selection, demonstration of growth, as well as freeze-storage techniques described in this paper permit selection and storage of porcine thyroid cells and the potential constitution of cell collections.     

Allosterism and Na++-d-glucose cotransport kinetics in rabbit jejunal vesicles: Compatibility with mixed positive and negative cooperativities in a homo- dimeric or tetrameric structure and experimental evidence for only one transport protein involved

Summary We first present two simple dimeric models of cotransport that may account for all of the kinetics of Na⁺⁺-d-glucose cotransport published so far in the small intestine. Both the sigmoidicity in the Na⁺⁺ activation of transport (positive cooperativity) and the upward deviations from linearity in the Eadie-Hofstee plots relative to glucose concentrations (negative cooperativity) can be rationalized within the concept of allosteric kinetic mechanisms corresponding to either of two models involving sequential or mixed concerted and sequential conformational changes. Such models also allow for 2 Na⁺⁺ 1 S and 1 Na⁺⁺ 1 S stoichiometries of cotransport at low and high substrate concentrations, respectively, and for partial inhibition by inhibitors or substrate analogues. Moreover, it is shown that the dimeric models may present physiological advantages over the seemingly admitted hypothesis of two different cotransporters in that tissue. We next address the reevaluation of Na⁺⁺-d-glucose cotransport kinetics in rabbit intestinal brush border membrane vesicles using stable membrane preparations, a dynamic approach with the Fast Sampling Rapid Filtration Apparatus (FSRFA), and both nonlinear regression and statistical analyses. Under different conditions of temperatures, Na⁺⁺ concentrations, and membrane potentials clamped using two different techniques, we demonstrate that our data can be fully accounted for by the presence of only one carrier in rabbit jejunal brush border membranes since transport kinetics relative to glucose concentrations satisfy simple Michaelis-Menten kinetics. Although supporting a monomeric structure of the cotransporter, such a conclusion would conflict with previous kinetic data and more recent studies implying a polymeric structure of the carrier protein. We thus consider a number of alternatives trying to reconcile the observation of Michaelis-Menten kinetics with allosteric mechanisms of cotransport associated with both positive and negative cooperativities for Na⁺⁺ and glucose binding, respectively. Such models, implying energy storage and release steps through conformational changes associated with ligand binding to an allosteric protein, provide a rational hypothesis to understand the long-time debated question of energy transduction from the Na⁺⁺ electrochemical gradient to the transporter.This research was supported by grant MT-7607 from the Medical Research Council of Canada. One of the authors (A.B.) was supported by a scholarship from the Fonds de la Recherche en Santé du Québec and C. C. was supported by a fellowship from the GRTM. The technical assistance of Mrs. C. Leroy has been greatly appreciated. The authors also thank D.D. Maenz and C. Malo for insightful discussions and C. Gauthier for the art work.     

睾丸注射法制备携带猪PID1基因的转基因兔

目的研究磷酸酪氨酸互作结构域1(PID1)基因与肌内脂肪含量的关系,探究睾丸注射法在转基因动物制备中的可行性。方法将携带猪PID1基因的重组质粒pIRES2-acGFP-PID1与转染试剂共孵育后,对新西兰兔进行了睾丸打点注射试验。对繁殖的F1代个体进行了活体荧光检测、PCR和western blotting检测,以及抽样屠宰进行肌内脂肪含量等检测;将F1代阳性个体互交,繁殖了F2代兔,对其进行了阳性率检测以及肌内脂肪含量检测。结果外源PID1基因和荧光蛋白基因在后代中均成功表达,其中,F1代阳性率为35.88%,F2代阳性率为34.33%;转基因阳性兔与阴性和空白对照兔相比,PID1蛋白表达水平有所增加,肌内脂肪含量有显著提高(P0.05)。结论 PID1基因与肌内脂肪沉积密切相关,同时,进一步证明了睾丸注射法可以用于制备转基因动物,且外源基因可以稳定遗传。     

兔防御素NP-1基因在转基因番茄中表达的初步研究

兔防御素ＮＰ－１是α－防御素的一种,含３３个氨基酸残基。最初从兔子的多形核嗜中性细胞中分离出来。它对革兰氏阴性菌、革兰氏阳性菌、分枝杆菌、真菌、被膜病毒以及ＨＩＶ病毒都有不同程度的抑制作用。兔防御素ＮＰ－１所带阳离子较多,可抗不具代谢活性的靶细胞。实验中将兔防御素ＮＰ－１基因构建到植物表达载体中,通过根瘤农杆菌介导转入番茄,得到了转基因番茄植株。对转基因番茄植株进行了ＰＣＲ、Ｓｏｕｔｈｅｍ杂交、Ｎ     

Genome-wide association study for feed efficiency in collective cage-raised rabbits under full and restricted feeding

Feed efficiency (FE) is one of the most economically and environmentally relevant traits in the animal production sector. The objective of this study was to gain knowledge about the genetic control of FE in rabbits. To this end, GWASs were conducted for individual growth under two feeding regimes (full feeding and restricted) and FE traits collected from cage groups, using 114 604 autosome SNPs segregating in 438 rabbits. Two different models were implemented: (1) an animal model with a linear regression on each SNP allele for growth trait; and (2) a two-trait animal model, jointly fitting the performance trait and each SNP allele content, for FE traits. This last modeling strategy is a new tool applied to GWAS and allows information to be considered from non-genotyped individuals whose contribution is relevant in the group average traits. A total of 189 SNPs in 17 chromosomal regions were declared to be significantly associated with any of the five analyzed traits at a chromosome-wide level. In 12 of these regions, 20 candidate genes were proposed to explain the variation of the analyzed traits, including genes such as FTO, NDUFAF6 and CEBPA previously associated with growth and FE traits in monogastric species. Candidate genes associated with behavioral patterns were also identified. Overall, our results can be considered as the foundation for future functional research to unravel the actual causal mutations regulating growth and FE in rabbits.     

A 7-bp insertion in the 3' untranslated region suggests the duplication and concerted evolution of the rabbit SRY gene

In this work we report the genetic polymorphism of a 7-bp insertion in the 3'' untranslated region of the rabbit SRY gene. The polymorphic GAATTAA motif was found exclusively in one of the two divergent rabbit Y-chromosomal lineages, suggesting that its origin is more recent than the separation of the O. c. algirus and O. c. cuniculus Y-chromosomes. In addition, the remarkable observation of haplotypes exhibiting 0, 1 and 2 7-bp inserts in essentially all algirus populations suggests that the rabbit SRY gene is duplicated and evolving under concerted evolution.     

Inhibition of glutathione reductase by cadmium ion in some rabbit tissues and the protective role of dietary selenium

This study is aimed at investigating the inhibitory effect of cadmium ion on glutathione reductase activity of rabbit brain and liver and the relationship of this effect with dietary selenium. For this purpose, one group of New Zealand rabbits were fed a selenium-deficient diet, another group was fed a selenium-rich diet, and the control group was fed a normal diet. The brain and liver tissues of these groups were investigated for the in vitro inhibitory effects of Cd²⁺ on glutathione reductase activity. For liver, the percentage inhibition of glutathione reductase by 40 nmol/mg protein of Cd²⁺ was similar for selenium-deficient and control groups, but significantly lower in the selenium-rich group. For brain tissues, there was no difference with respect to cadmium inhibition of glutathione reductase in all three groups.