Colony aging affects the reproductive performance of Swiss Webster females used as recipients for embryo transfer

The objective was to evaluate the influence of colony aging in a Swiss Webster (SW) outbred stock used as recipients for embryo transfer. In the first study, a retrospective analysis was performed throughout several generations during a 38-month period in 2,398 embryos transferred to 108 SW recipients. A decrease in the percentage of live pups from transferred embryos was found at the end of the period. Impairment occurred due to the incidence of maternal cannibalism that increased from 0% to 67-100% (P<0.05), while pregnancy rate (pregnant/transferred recipients) and number of pups per delivered female were not affected throughout the period (P=NS). A following study was carried out to compare the reproductive performance of SW stock vs. B6D2F1 hybrid females in a 5-year interval. The study was conducted on a total of 893 embryos transferred to 40 females (20 SW and 20 B6D2F1) in Year #1, and 514 embryos transferred to 30 females (15 SW and 15 B6D2F1) in Year #5. No cases of maternal cannibalism were found on Year #1 in any of the strains (0/10 and 0/10). However, an incidence of 44,4% (4/9) was seen on Year #5 for SW, while for B6D2F1 the incidence was 0% (0/12) (P<0.05). Further examination of the uterus showed endometrial cysts and abnormal implantation sites in SW on Year #5 but not in B6D2F1 females. In conclusion, this study reports an impairment of the reproductive performance of an early aged SW outbred stock colony mainly due to the occurrence of maternal cannibalism. This finding has important implications for embryo transfer programs conducted in mouse facilities.     

Ku suppresses formation of telomeric circles and alternative telomere lengthening in Arabidopsis

Telomeres in mammals and plants are protected by the terminal t loop structure, the formation of which parallels the first steps of intrachromatid homologous recombination (HR). Under some circumstances, cells can also utilize an HR-based mechanism (alternative lengthening of telomeres [ALT]) as a back-up pathway for telomere maintenance. We have found that the Ku70/80 heterodimer, a central nonhomologous end-joining DNA repair factor, inhibits engagement of ALT in Arabidopsis telomerase-negative cells. To further assess HR activities at telomeres, we have developed a sensitive assay for detecting extrachromosomal telomeric circles (t circles) that may arise from t loop resolution and aberrant HR. We show that Ku70/80 specifically inhibits circle formation at telomeres, but not at centromeric and rDNA repeats. Ku inactivation results in increased formation of t circles that represent approximately 4% of total telomeric DNA. However, telomeres in ku mutants are fully functional, indicating that telomerase efficiently heals ongoing terminal deletions arising from excision of the t circles.     

The mere exposure effect in the domain of haptics

Background

Zajonc showed that the attitude towards stimuli that one had been previously exposed to is more positive than towards novel stimuli. This mere exposure effect (MEE) has been tested extensively using various visual stimuli. Research on the MEE is sparse, however, for other sensory modalities.

Methodology/Principal Findings

We used objects of two material categories (stone and wood) and two complexity levels (simple and complex) to test the influence of exposure frequency (F0 = novel stimuli, F2 = stimuli exposed twice, F10 = stimuli exposed ten times) under two sensory modalities (haptics only and haptics & vision). Effects of exposure frequency were found for high complex stimuli with significantly increasing liking from F0 to F2 and F10, but only for the stone category. Analysis of “Need for Touch” data showed the MEE in participants with high need for touch, which suggests different sensitivity or saturation levels of MEE.

Conclusions/Significance

This different sensitivity or saturation levels might also reflect the effects of expertise on the haptic evaluation of objects. It seems that haptic and cross-modal MEEs are influenced by factors similar to those in the visual domain indicating a common cognitive basis.     

Identification of a novel, highly variable amino-terminal amino acid sequence element in the nuclear intermediate filament protein lamin B(2) from higher vertebrates

By comparing newly available cDNA sequences of the human intermediate filament protein lamin B(2) with published sequences, we have identified an additional translation initiation codon 60 nucleotides upstream of the previously assumed translation start. In addition, corresponding sequences were identified in the chimpanzee, mouse, rat and bovine genes and cDNAs, respectively. Therefore, we generated antibodies against these potential 20 new amino acids of the human sequence. By immunoblot analysis and immunofluorescence microscopy we show that human lamin B(2) is indeed synthesized as a longer version than previously reported, because it contains these additional 20 amino acids. Notably, the sequence homology to mouse, rat and bovine lamin B(2) is significantly lower in this segment than in that between the second methionine codon and the start of the alpha-helical rod indicating that the tip of the "head" is engaged in more species-specific functions. Forced expression of the GFP-tagged authentic "long" and the 20 amino acid shorter version of lamin B(2) in human cultured SW-13 cells demonstrated that both the longer and the shorter version are properly integrated into the nuclear lamina, although the shorter version exhibited a tendency to disturb envelope architecture at higher expression levels.     

Soil type is the primary determinant of the composition of the total and active bacterial communities in arable soils

Degradation of agricultural land and the resulting loss of soil biodiversity and productivity are of great concern. Land-use management practices can be used to ameliorate such degradation. The soil bacterial communities at three separate arable farms in eastern England, with different farm management practices, were investigated by using a polyphasic approach combining traditional soil analyses, physiological analysis, and nucleic acid profiling. Organic farming did not necessarily result in elevated organic matter levels; instead, a strong association with increased nitrate availability was apparent. Ordination of the physiological (BIOLOG) data separated the soil bacterial communities into two clusters, determined by soil type. Denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism analyses of 16S ribosomal DNA identified three bacterial communities largely on the basis of soil type but with discrimination for pea cropping. Five fields from geographically distinct soils, with different cropping regimens, produced highly similar profiles. The active communities (16S rRNA) were further discriminated by farm location and, to some degree, by land-use practices. The results of this investigation indicated that soil type was the key factor determining bacterial community composition in these arable soils. Leguminous crops on particular soil types had a positive effect upon organic matter levels and resulted in small changes in the active bacterial population. The active population was therefore more indicative of short-term management changes.     

Animal-derived antigenic variants of foot-and-mouth disease virus type A12 have low affinity for cells in culture.

We recently have shown that binding of foot-and-mouth disease virus (FMDV) to cells in culture requires an arginine-glycine-aspartic acid (RGD) sequence in the G-H loop of the capsid protein VP1 (P. W. Mason, E. Rieder, and B. Baxt, Proc. Natl. Acad. Sci. USA 91:1932-1936, 1994). In this report, we show that FMDV type A12 viruses found in infected bovine tongue tissue (BTT) differ from their tissue culture-grown derivatives at amino acid residues near the RGD. Viruses genetically engineered to contain VP1 sequences found in animal tissue (BTT viruses) were antigenically different from their tissue culture derivatives and bound to BHK cells more poorly than did the tissue culture-adapted viruses. Passage of the genetically engineered BTT viruses in BHK cells resulted in the rapid selection of variants with cell-binding properties, antigenic characteristics, and sequences typical of tissue culture-adapted viruses. These data indicate that residues near the RGD are critical for cell binding and that interpretations of antigenic variation of FMDV can be affected by virus cultivation in vitro.     

Chemical Diversity of the Natural Populations of Dalmatian Pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch.Bip.) in Croatia

Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir. ) Sch.Bip. ) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households. A total of 25 Dalmatian pyrethrum populations from Croatia were studied to determine the pyrethrin content and composition, and to identify distinct chemotypes. The total pyrethrin content ranged from 0.36 to 1.30% (dry flower weight; DW) and the pyrethrin I/pyrethrin II ratio ranged from 0.64 to 3.33%. The statistical analyses revealed that the correlations between the percentage of pyrethrin I and of all the other components were significant and negative. The total pyrethrin content was positively correlated with the percentage of pyrethrin I and negatively correlated with cinerin II. The multivariate analysis of the chemical variability enabled the identification of five chemotypes among 25 Dalmatian pyrethrum populations. The chemical characterization of indigenous Dalmatian pyrethrum populations may serve as a good background for future breeding and agricultural exploitation.     

Genome‐wide association studies based on sequence‐derived genotypes reveal new QTL associated with conformation and performance traits in the Franches–Montagnes horse breed

To identify novel quantitative trait loci (QTL) within horses, we performed genome‐wide association studies (GWAS) based on sequence‐level genotypes for conformation and performance traits in the Franches–Montagnes (FM) horse breed. Sequence‐level genotypes of FM horses were derived by re‐sequencing 30 key founders and imputing 50K data of genotyped horses. In total, we included 1077 FM horses genotyped for ~4 million SNPs and their respective de‐regressed breeding values of the traits in the analysis. Based on this dataset, we identified a total of 14 QTL associated with 18 conformation traits and one performance trait. Therefore, our results suggest that the application of sequence‐derived genotypes increases the power to identify novel QTL which were not identified previously based on 50K SNP chip data.