Mapping genes that control hormone-induced ovulation rate in mice.

The present study mapped quantitative trait loci (QTL) that control 6-fold genetic differences in hormone-induced ovulation rate (HIOR) between C57BL/6J (B6) (HIOR = 54) and A/J strain mice (HIOR = 9). (The gene name is Ovulation Rate Induced [ORI] QTL and the gene symbol is Oriq.) QTL linkage analysis was conducted on 167 (B6xA)xA backcross mice at 165 loci. Suggestive B6 ORI QTL that control the number of eggs in cumulus mapped, as follows, near: Cyp19 and D9Mit4 on chromosome (Chr) 9 (Oriq1); D2Mit433 on Chr2 (Oriq2); D6Mit316 on Chr6 (Oriq3); DXMit22 on ChrX (Oriq4) and were associated with a 2.7, 2.7, 2.6, and 4.2 egg increases in HIOR, respectively. Oriq3 was significant (LOD = 3.45) based on composite interval mapping. QTL linkage analysis of the number of eggs matured by endogenous gonadotropins and ovulated by eCG mapped a significant Oriq5 to Chr 10 and suggestive Oriq to Chr 6, 7, and X. These data provide the first molecular genetic markers for reproductive QTL that control major differences in ovarian responsiveness to gonadotropins. These and closely linked syntenic molecular markers will enable a more accurate prediction of ovarian responsiveness to gonadotropins and provide selection criteria for improving reproductive performance in diverse mammalian species.     

哈尔滨西郊赤狐冬季巢区的初步研究

本文利用雪地跟踪方法对哈尔滨西郊5只赤狐在1985-1986年冬季的巢区做了观察。结果表明,5只狐对巢区内各部分使用的强度是不等的,对巢区中部的某些地块使用强度要高于对外围的使用,并具有明显的方向性。5个巢区的平均活动半径为320±68米至557±82米,面积为1.44-4.O9平方公里,线性指数为1.079至2。5只狐相邻距离约1000米。     

Nonglucosylated oligosaccharides are transferred to protein in MI8-5 Chinese hamster ovary cells

A CHO mutant MI8-5 was found to synthesize Man9-GlcNAc2-P-P-dolichol rather than Glc3Man9GlcNAc2-P-P-dolichol as the oligosaccharide-lipid intermediate in N-glycosylation of proteins. MI8-5 cells were incubated with labeled mevalonate, and the prenol was found to be dolichol. The mannose-labeled oligosaccharide released from oligosaccharide-lipid of MI8-5 cells was analyzed by HPLC and alpha-mannosidase treatment, and the data were consistent with a structure of Man9GlcNAc2. In addition, MI8-5 cells did not incorporate radioactivity into oligosaccharide- lipid during an incubation with tritiated galactose, again consistent with MI8-5 cells synthesizing an unglucosylated oligosaccharide-lipid. MI8-5 cells had parental levels of glucosylphosphoryldolichol synthase activity. However, in two different assays, MI8-5 cells lacked dolichol- P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase activity. MI8-5 cells were found to synthesize glucosylated oligosaccharide after they were transfected with Saccharomyces cerevisiae ALG 6, the gene for dolichol-P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase. MI8-5 cells were found to incorporate mannose into protein 2-fold slower than parental cells and to approximately a 2-fold lesser extent.      

Review: Risk assessment implications of variation in susceptibility to perchloroethylene due to genetic diversity,ethnicity, age,gender, diet and pharmaceuticals

Current cancer risk assessments do not adequately consider impacts of human inter-individual variability on susceptibility to environmental pollutants like perchloroethylene (PCE). PCE is metabolized through both oxidative and glutathione (GSH) conjugation pathways. Toxicity criteria derived using both pathways are 23-fold more stringent than those calculated using only oxidative metabolism. While toxicokinetic modeling of PCE metabolism predicted very high variability through the GSH conjugation pathway, it is unclear if the range in estimates is due to human variability or uncertainty. Thus, the variation in the GSH conjugation pathway of PCE metabolism due to genetics, ethnicity, age, gender, diet, and pharmaceutical co-exposures is examined. Genetic polymorphisms were found at several loci including, GSTT1, GSTM1, CCBL1, AGXT2, NAT8, ACY3, MRP2, OAT1/3, FMO3, and CYP3A that code for enzymes/transporters in the GSH conjugation pathway. Genetic diversity in GSTT1, GSTM1, and CCBL1 between ethnic populations, as well as age, gender, diet, and pharmaceutical co-exposures influences toxic and mutagenic metabolites produced through this pathway. Given this diversity, large differences in PCE metabolism through the GSH conjugation pathway are expected. To be health protective for diverse ethnic populations and lifestyles, both the oxidative and GSH conjugation pathways need to be considered in developing PCE toxicity criteria.     

Major genes control hormone-induced ovulation rate in mice

The present study examined the magnitude of genetic variation, mode of inheritance and number of loci controlling major genetic differences in hormone-induced ovulation rate in mice. Mice were injected with 5 i.u. PMSG at 28 days of age and 5 i.u. hCG at 30 days, and hormone-induced ovulation rate was determined from counts of oviducal eggs in cumulus the next morning. Six-fold genetic differences in induced ovulation rate were detected amongst strains, ranging from a low mean (+/- s.e.) value of 8.8 (+/- 0.9) in A/J up to 53.5 (+/- 2.2) in C57BL/6J. The number of ova differed significantly amongst strains and amongst F1 crosses (P less than 0.0001): 70% of the variation in hormone-induced ovulation rate was amongst strains. Of 9 F1 crosses examined, 4 showed positive heterosis, 3 showed no heterosis and 2 showed negative heterosis for hormone-induced ovulation rate. Analysis of parental, F1 and F2 generations revealed that the induced ovulation rate of A/J and C57BL/6J mice differed due to the action of about 3 or 4 loci, and A.SW/SnJ and SJL/J mice differed due to the action of about 2 to 3 loci. Analysis of recombinant inbred strains formed from A/J and C57BL/6J confirmed that these strains differed due to the action of a small number of loci. This study demonstrates the existence of a small number of major genes controlling hormone-induced ovulation rate in young mice.     

Comparative genomic analysis reveals significant enrichment of mobile genetic elements and genes encoding surface structure-proteins in hospital-associated clonal complex 2 Enterococcus faecalis

Background  

Enterococci rank among the leading causes of nosocomial infections. The failure to identify pathogen-specific genes in Enterococcus faecalis has led to a hypothesis where the virulence of different strains may be linked to strain-specific genes, and where the combined endeavor of the different gene-sets result in the ability to cause infection. Population structure studies by multilocus sequence typing have defined distinct clonal complexes (CC) of E. faecalis enriched in hospitalized patients (CC2, CC9, CC28 and CC40).     

Regenerative potential of human muscle stem cells in chronic inflammation

Introduction

Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle.

Methods

As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation.

Results

After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group.

Conclusions

In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate.     

Tint maps to mouse chromosome 6 and may interact with a notochordal enhancer of Brachyury

At the proximal part of mouse chromosome 17 there are three well-defined genes affecting the axis of the embryo and consequently tail length: Brachyury, Brachyury the second, and the t-complex tail interaction (T1, T2, and tct). The existence of T1 and tct in fact defines the classical "t-complex" that occupies approximately 40 cM of mouse chromosome 17. Their relationship to each other and various unlinked interacting genes has been enigmatic. The tint gene was the first of the latter to be identified. We report here its genetic mapping using a microsatellite scan together with outcrosses to Mus spretus and M. castaneous followed by a subsequent testcross to T, T1, and T2 mutants. Surprisingly, tint interacts with T2 but not with T1. The implications of our data suggest that T2 may be part of the T1 regulatory region through direct or indirect participation of tint.