If you knew what was good for you! The value of environmental enrichments with known welfare benefits is not demonstrated by sows using operant techniques

This study assessed the motivation of gestating sows housed in standard, barren gestation stalls (used for breeding/implantation and/or gestation) for access to environmental enrichment. Enrichment consisted of a cotton rope or rubber mat in comparison to positive (additional food when fed at commercial levels) and negative (empty trough) controls. Although environmental enrichment may improve animal welfare, sows' valuation of enrichments is largely unknown. This study used an operant panel and obtained behavioral measures to quantify motivation. As indicated by a higher price paid and lower latencies to press the panel and enter the treatment stall (all comparisons, p < .05), sows demonstrated higher motivation for food compared with all treatments. Sows housed in gestation stalls did not demonstrate high motivation via operant responding for a cotton rope or a rubber mat; nor did they demonstrate any differences in behavioral measures (all comparisons, p > .10). Although sows' motivation for a mat did not differ from that for an empty trough, previous work has demonstrated the welfare benefits associated with comfort flooring.     

Postprandial leg uptake of triglyceride is greater in women than in men

The postprandial excursion of plasma triglyceride (TG) concentration is greater in men than in women. In this study, the disposition of dietary fat was examined in lean healthy men and women (n = 8/group) in either the overnight-fasted or fed (4.5 h after breakfast) states. A [14C]oleate tracer was incorporated into a test meal, providing 30% of total daily energy requirements. After ingestion of the test meal, measures of arteriovenous differences in TG and 14C across the leg were combined with needle biopsies of skeletal muscle and adipose tissue and respiratory gas collections to define the role of skeletal muscle in the clearance of dietary fat. The postprandial plasma TG and 14C tracer excursions were lower (P = 0.04) in women than in men in the overnight-fasted and fed states. Women, however, had significantly greater limb uptake of total TG compared with men on both the fasted (3,849 +/- 846 vs. 528 +/- 221 total micro mol over 6 h) and fed (4,847 +/- 979 vs. 1,571 +/- 334 total micromol over 6 h) days. This was also true for meal-derived 14C lipid uptake. 14C content of skeletal muscle tissue (micro Ci/g tissue) was significantly greater in women than in men 6 h after ingestion of the test meal. In contrast, 14C content of adipose tissue was not significantly different between men and women at 6 h. The main effect of nutritional state, fed vs. fasted, was to increase the postmeal glucose (P = 0.01) excursion (increase from baseline) and decrease the postmeal TG excursion (P = 0.02). These results support the notion that enhanced skeletal muscle clearance of lipoprotein TG in women contributes to their reduced postprandial TG excursion. Questions remain as to the mechanisms causing these sex-based differences in skeletal muscle TG uptake and metabolism. Furthermore, nutritional state can significantly impact postprandial metabolism in both men and women.     

Evolution of a signalling system that incorporates both redundancy and diversity: Arabidopsis SUMOylation

The reversible post-translational modifier, SUMO (small ubiquitin-related modifier), modulates the activity of a diverse set of target proteins, resulting in important consequences to the cellular machinery. Conjugation machinery charges the processed SUMO so that it can be linked via an isopeptide bond to a target protein. The removal of SUMO moieties from conjugated proteins by isopeptidases regenerates pools of processed SUMOs and unmodified target proteins. The evolutionarily conserved SUMO-conjugating proteins, E1 and E2, recognize a diverse set of Arabidopsis SUMO proteins using them to modify protein substrates. In contrast, the deSUMOylating enzymes differentially recognize the Arabidopsis SUMO proteins, resulting in specificity of the deconjugating machinery. The specificity of the Arabidopsis deSUMOylating enzymes is further diversified by the addition of regulatory domains. Therefore the SUMO proteins, in this signalling system, have evolved to contain information that allows not only redundancy with the conjugation system but also diversity with the deconjugating enzymes.     

Cytogenetic analysis of 400 sperm from three translocation heterozygotes

Summary Sperm chromosome complements were studied in three men who carried reciprocal translocations. A total of 400 sperm were karyotyped after in vitro penetration of hamster eggs: 217 sperm from t(2;9) (q21;p22), 164 from t(4;6) (q28;p23) and 19 from t(7;14) (q21;q13). All possible 22 and 31 meiotic segregations were observed for t(2;9) and t(4;6); for t(7;14) only 22 segregations were observed. For alternate segregations, the number of normal sperm was not significantly different from the number of sperm carrying a balanced form of the translocation in any of the translocations, as theoretically expected. The percentage of sperm with an unbalanced form of the translocation was 57% for t(2;9), 54% for t(4;6) and 47% for t(7;14). There was no evidence for an interchromosomal effect in any of the translocations since the frequencies of numerical abnormalities (unrelated to the translocation) were within the normal range of control donors. The frequencies of X- and Y-bearing sperm did not differ significantly from 50%. Results from a total of 17 reciprocal translocations studied by sperm chromosomal analysis were reviewed.     

The role of EMF1 in regulating the vegetative and reproductive transition in Arabidopsis thaliana (Brassicaceae)

To understand the genetic regulation of vegetative to reproductive transition in higher plants, further characterization of the Arabidopsis mutant embryonic flower1, emf1, was conducted. Using three flowering symptoms, we showed that emf1 mutants could only grow reproductive and not rosette shoots under five different growth conditions. The mutant embryos did not produce the typical tunica–corpus shoot apical structures at the heart-, torpedo-, and mature stages. The divergent shoot apical development during mutant and wild-type embryogenesis indicated that the wild-type EMF1 gene was expressed in early embryogenesis. Mutations in the EMF1 gene affected the embryonic shoot apical development and caused the germinating embryo and regenerating callus to grow inflorescence, instead of rosette, shoots. Our results support the hypothesis that the EMF1 gene regulates the switch between vegetative and reproductive growth in Arabidopsis.     

Functional levels of mitochondrial anion transport proteins in non-insulin-dependent diabetes mellitus

The effect of non-insulin-dependent diabetes mellitus (i.e., NIDDM; type 2 diabetes) on the levels of functional mitochondrial anion transport proteins has been determined utilizing a chemically-induced neonatal model of NIDDM. We hypothesized that moderate insulin deficiency exacerbated by the insulin resistance, which is characteristic of NIDDM, would cause changes in mitochondrial anion transporter function that were similar to those we have previously shown to occur in insulin-dependent diabetes mellitus (i.e., IDDM; type 1 diabetes) (Arch. Biochem. Biophys. 280: 181–191, 1990). Our experimental approach consisted of the extraction of the pyruvate, dicarboxylate and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using rat liver mitoplasts (prepared from diabetic and control animals) as the starting material, followed by the functional reconstitution of each transporter in a proteoliposomal system. This strategy permitted the quantification of the functional levels of these three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria (or mitoplasts). We found that experimental NIDDM did not cause significant changes in the extractable and reconstitutable specific (and total) transport activities of the pyruvate, dicarboxylate, and citrate transporters. These results are in marked contrast to our previous findings obtained using rats with IDDM and negated our hypothesis. The present results, in combination with our earlier findings, allow us to conclude that insulin plays an important role in the regulation of mitochondrial anion transporter function. Accordingly, in this model of NIDDM, where the level of insulin is not profoundly deficient, transporter function is unaltered, whereas in IDDM, where a profound insulinopenia exists, transporter function is altered. Furthermore, the present studies suggest that in the neonatal model of NIDDM the three mitochondrial transporters investigated are neither affected by, nor are they the sites of the well documented hepatic post-receptor insulin resistance which is characteristic of this disease.     

Mechanism of Prion Loss after Hsp104 Inactivation in Yeast

In vivo propagation of [PSI(+)], an aggregation-prone prion isoform of the yeast release factor Sup35 (eRF3), has previously been shown to require intermediate levels of the chaperone protein Hsp104. Here we perform a detailed study on the mechanism of prion loss after Hsp104 inactivation. Complete or partial inactivation of Hsp104 was achieved by the following approaches: deleting the HSP104 gene; modifying the HSP104 promoter that results in low level of its expression; and overexpressing the dominant-negative ATPase-inactive mutant HSP104 allele. In contrast to guanidine-HCl, an agent blocking prion proliferation, Hsp104 inactivation induced relatively rapid loss of [PSI(+)] and another candidate yeast prion, [PIN(+)]. Thus, the previously hypothesized mechanism of prion dilution in cell divisions due to the blocking of prion proliferation is not sufficient to explain the effect of Hsp104 inactivation. The [PSI(+)] response to increased levels of another chaperone, Hsp70-Ssa, depends on whether the Hsp104 activity is increased or decreased. A decrease of Hsp104 levels or activity is accompanied by a decrease in the number of Sup35(PSI+) aggregates and an increase in their size. This eventually leads to accumulation of huge agglomerates, apparently possessing reduced prion forming capability and representing dead ends of the prion replication cycle. Thus, our data confirm that the primary function of Hsp104 in prion propagation is to disassemble prion aggregates and generate the small prion seeds that initiate new rounds of prion propagation (possibly assisted by Hsp70-Ssa).     

A nuclear protein associated with cell divisions in plants

A nuclear protein, present in carrot meristems and rapidly proliferating cultured cells of carrot (Daucus carota L.) has been identified by the use of a monoclonal antibody (MAb 21D7). By combining the techniques of two-dimensional polyacrylamide gel analysis and blotting separated proteins onto nitrocellulose sheets, it was shown that the antibody detected a single polypeptide of apparent molecular mass (M _r) of 45000 and an isoelectric focusing point (pI) of 6.7. This protein was found by subcellular fractionation and immunofluorescence to be highly concentrated in the nucleoli of somatic and zygotic embryos of a wide range of plants. It was not detectable in logarthmically growing cells ofEscherichia coli, yeast, embryos ofDrosophila melanogaster or cultured C3H mouse cells. These data indicate that this protein is a highly conserved non-histone protein associated with nuclei of rapidly dividing plant cells.Abbreviations M _r apparent molecular mass - Da dalton - Ig immunoglobulins - MAb monoclonal antibody - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis - 2-D gel two-dimensional gel electrophoresis - 2,4-D 2,4-dichlorophenoxyacetic acid     

Inhibition of the rat adrenal ornithine decarboxylase activity by immobilization stress and/or dexamethasone

The effects of immobilization stress and/or dexamethasone (DEX) on the adrenal ornithine decarboxylase (ODC) activities of sham-operated and adrenal-medulloectomized (enucleated) male Sprague-Dawley rats were investigated. On day 11 after surgery, rats were injected with saline or DEX (1 mg/kg), 3 h before the time of sacrifice (0600 h or 1800 h). Four groups, from sham-operated and enucleated rats (ENU) treated with saline or DEX were subjected to immobilization stress for 1 h prior to sacrifice. Groups of rats from stress-sham-DEX, non stress-sham-DEX, stress-sham, non stress-sham, stress-ENU-DEX, non stress-ENU-DEX, stress-ENU, and non stress-ENU were sacrificed at 0600 h or 1800 h on day 11 after surgery. Adrenal glands were excised and later analyzed for ODC activities. Results indicated that DEX and/or immobilization stress inhibited ODC activities (p < 0.05) in normal and regenerating adrenal glands at 1800 h and ODC activity varies diurnally, the activity being greater at 1800 h than at 0600 hours (p < 0.001).     

Klebsiella pneumoniae multiresistance plasmid pMET1: similarity with the Yersinia pestis plasmid pCRY and integrative conjugative elements

Background

Dissemination of antimicrobial resistance genes has become an important public health and biodefense threat. Plasmids are important contributors to the rapid acquisition of antibiotic resistance by pathogenic bacteria.

Principal Findings

The nucleotide sequence of the Klebsiella pneumoniae multiresistance plasmid pMET1 comprises 41,723 bp and includes Tn1331.2, a transposon that carries the bla _TEM-1 gene and a perfect duplication of a 3-kbp region including the aac(6′)-Ib, aadA1, and bla _OXA-9 genes. The replication region of pMET1 has been identified. Replication is independent of DNA polymerase I, and the replication region is highly related to that of the cryptic Yersinia pestis 91001 plasmid pCRY. The potential partition region has the general organization known as the parFG locus. The self-transmissible pMET1 plasmid includes a type IV secretion system consisting of proteins that make up the mating pair formation complex (Mpf) and the DNA transfer (Dtr) system. The Mpf is highly related to those in the plasmid pCRY, the mobilizable high-pathogenicity island from E. coli ECOR31 (HPI_ECOR31), which has been proposed to be an integrative conjugative element (ICE) progenitor of high-pathogenicity islands in other Enterobacteriaceae including Yersinia species, and ICE_Kp1, an ICE found in a K. pneumoniae strain causing primary liver abscess. The Dtr MobB and MobC proteins are highly related to those of pCRY, but the endonuclease is related to that of plasmid pK245 and has no significant homology with the protein of similar function in pCRY. The region upstream of mobB includes the putative oriT and shares 90% identity with the same region in the HPI_ECOR31.

Conclusions

The comparative analyses of pMET1 with pCRY, HPI_ECOR31, and ICE_Kp1 show a very active rate of genetic exchanges between Enterobacteriaceae including Yersinia species, which represents a high public health and biodefense threat due to transfer of multiple resistance genes to pathogenic Yersinia strains.