Seasonal pattern of LH and testosterone secretion in adult male fallow deer, Dama dama

At monthly intervals during the year blood samples were collected every 20 min for 12 h from 4 entire and 2 prepubertally castrated adult fallow deer bucks. In the entire bucks there were seasonal changes in mean concentrations and pulse frequencies of plasma LH. Mean concentrations in late summer and autumn were 3-6 times higher than during other seasons. LH pulse frequency was low (0-1 pulses/12 h) during most of the year and increased only during the 2-month period (January and February) that marked the transition from the non-breeding season to the autumn rut. During this period there was a close temporal relationship between pulses of LH and testosterone. However, during the rutting period (March and April) episodic secretion of testosterone, manifest as surges in plasma concentrations of 4-6 h duration, was not associated with any detectable pulses in LH although mean plasma concentrations of LH remained elevated. During the rut, the surges of plasma testosterone occurred at similar times of the day. Plasma profiles in May indicated very low concentrations of LH and testosterone secretion in the immediate post-rut period. Castrated bucks exhibited highly seasonal patterns of LH secretion, with mean plasma LH concentrations and LH pulse frequency being lowest in November (early summer) and highest in February and March (late summer-early autumn). Mean concentrations and pulse frequency of LH in castrated bucks were higher than for entire bucks at all times of the year.     

Novel class of nuclear genes involved in both mRNA splicing and protein synthesis in Saccharomyces cerevisiae mitochondria

Summary We have cloned three distinct nuclear genes, NAM1, NAM7, and NAM8, which alleviate mitochondrial intron mutations of the cytochrome b and COXI (subunit I of cytochrome oxidase) genes when present on multicopy plasmids. These nuclear genes show no sequence homology to each other and are localized on different chromosomes: NAM1 on chromosome IV, NAM7 on chromosome XIII and NAM8 on chromosome VIII. Sequence analysis of the NAM1 gene shows that it encodes a protein of 440 amino acids with a typical presequence that would target the protein to the mitochondrial matrix. Inactivation of the NAM1 gene by gene transplacement leads to a dramatic reduction of the overall synthesis of mitochondrial protein, and a complete absence of the COXI protein which is the result of a specific block in COXI pre-mRNA splicing. The possible mechanisms by which the NAM1 gene product may function are discussed.     

Multilocus patterns of polymorphism and selection across the X chromosome of Caenorhabditis remanei

Natural selection and neutral processes such as demography, mutation, and gene conversion all contribute to patterns of polymorphism within genomes. Identifying the relative importance of these varied components in evolution provides the principal challenge for population genetics. To address this issue in the nematode Caenorhabditis remanei, I sampled nucleotide polymorphism at 40 loci across the X chromosome. The site-frequency spectrum for these loci provides no evidence for population size change, and one locus presents a candidate for linkage to a target of balancing selection. Selection for codon usage bias leads to the non-neutrality of synonymous sites, and despite its weak magnitude of effect (N(e)s approximately 0.1), is responsible for profound patterns of diversity and divergence in the C. remanei genome. Although gene conversion is evident for many loci, biased gene conversion is not identified as a significant evolutionary process in this sample. No consistent association is observed between synonymous-site diversity and linkage-disequilibrium-based estimators of the population recombination parameter, despite theoretical predictions about background selection or widespread genetic hitchhiking, but genetic map-based estimates of recombination are needed to rigorously test for a diversity-recombination relationship. Coalescent simulations also illustrate how a spurious correlation between diversity and linkage-disequilibrium-based estimators of recombination can occur, due in part to the presence of unbiased gene conversion. These results illustrate the influence that subtle natural selection can exert on polymorphism and divergence, in the form of codon usage bias, and demonstrate the potential of C. remanei for detecting natural selection from genomic scans of polymorphism.     

Use and husbandry of captive European starlings (Sturnus vulgaris) in scientific research: a review of current practice

We reviewed the use of captive European starlings (Sturnus vulgaris) in scientific research published between 2000 and 2004. We estimated the numbers of birds used and documented their origin and the range of husbandry regimes employed with the aim of comparing current practice with the new European guidelines for husbandry of laboratory animals. Over the five-year period, 106 primary articles report the use of an estimated total of 2490 captive starlings. The majority of birds were caught from the wild either as adults or fledglings, and only 3% were hand-reared from chicks. There was considerable variation in husbandry. In the majority of cases, standards fell below those currently recommended as best practice in the UK and cited in new European guidelines. The median volume of home cages employed was 0.42 m3 (0.13-5.1 m3, interquartile range), whereas current recommendations suggest a minimum of 1.0 m3 for a singly-housed bird. The median volume of space allowed per bird was 0.13 m3/bird (0.08-1.05 m3/bird, Q1-Q3), whereas current recommendations suggest a minimum of 0.33 m3/bird. Only 27% of the articles mentioned providing any form of environmental enrichment for birds in their home cages. We recommend that more research be conducted into the welfare of starlings to inform legislation and guidelines, and thus maximize the welfare of captive animals.     

Changes in microbial diversity in industrial wastewater evaporation ponds following artificial salination

The salinity of industrial wastewater evaporation ponds was artificially increased from 3-7% to 12-16% (w/v), in an attempt to reduce the activity of sulfate-reducing bacteria (SRB) and subsequent emission of H2S. To investigate the changes in bacterial diversity in general, and SRB in particular, following this salination, two sets of universal primers targeting the 16S rRNA gene and the functional apsA [adenosine-5'-phosphosulfate (APS) reductase alpha-subunit] gene of SRB were used. Phylogenetic analysis indicated that Proteobacteria was the most dominant phylum both before and after salination (with 52% and 68%, respectively), whereas Firmicutes was the second most dominant phylum before (39%) and after (19%) salination. Sequences belonging to Bacteroidetes, Spirochaetes and Actinobacteria were also found. Several groups of SRB from Proteobacteria and Firmicutes were also found to inhabit this saline environment. Comparison of bacterial diversity before and after salination of the ponds revealed both a shift in community composition and an increase in microbial diversity following salination. The share of SRB in the 16S rRNA gene was reduced following salination, consistent with the reduction of H2S emissions. However, the community composition, as shown by apsA gene analysis, was not markedly affected.     

Role of adenosine A1 and A3 receptors in regulation of cardiomyocyte homeostasis after mitochondrial respiratory chain injury

Activation of either the A(1) or the A(3) adenosine receptor (A(1)R or A(3)R, respectively) elicits delayed cardioprotection against infarction, ischemia, and hypoxia. Mitochondrial contribution to the progression of cardiomyocyte injury is well known; however, the protective effects of adenosine receptor activation in cardiac cells with a respiratory chain deficiency are poorly elucidated. The aim of our study was to further define the role of A(1)R and A(3)R activation on functional tolerance after inhibition of the terminal link of the mitochondrial respiratory chain with sodium azide, in a state of normoxia or hypoxia, compared with the effects of the mitochondrial ATP-sensitive K(+) channel opener diazoxide. Treatment with 10 mM sodium azide for 2 h in normoxia caused a considerable decrease in the total ATP level; however, activation of adenosine receptors significantly attenuated this decrease. Diazoxide (100 muM) was less effective in protection. During treatment of cultured cardiomyocytes with hypoxia in the presence of 1 mM sodium azide, the A(1)R agonist 2-chloro-N(6)-cyclopentyladenosine was ineffective, whereas the A(3)R agonist 2-chloro-N(6)-iodobenzyl-5'-N-methylcarboxamidoadenosine (Cl-IB-MECA) attenuated the decrease in ATP level and prevented cell injury. Cl-IB-MECA delayed the dissipation in the mitochondrial membrane potential during hypoxia in cells impaired in the mitochondrial respiratory chain. In cells with elevated intracellular Ca(2+) concentration after hypoxia and treatment with NaN(3) or after application of high doses of NaN(3), Cl-IB-MECA immediately decreased the elevated intracellular Ca(2+) concentration toward the diastolic control level. The A(1)R agonist was ineffective. This may be especially important for the development of effective pharmacological agents, because mitochondrial dysfunction is a leading factor in the pathophysiological cascade of heart disease.     

Modulation of cardiac A1-adenosine receptors in rats following treatment with agents affecting heart rate

Effects of chronic treatment affecting heart rate on A₁ adenosine receptor levels and their functions were studied. Treatment of rats with isoproterenol for 10 days accelerated heart rate and increased the level of adenosine receptors, in both the atria and ventricles. Negative dromotropic response of isolated heart to adenosine was enhanced in isoproterenol-treated rats. Similar results were obtained following treatment with atropine sulfate, or swimming training but not after treatment with thyroxine. On the other hand, treatment with amiodarone, which normally causes a decrease in heart rate, also increased the level of adenosine receptors in both atria and ventricles. The sensitivity of the isolated heart to the negative dromotropic and chronotropic effects of adenosine was not enhanced in the amiodarone treated rats. Similar results were obtained following treatment with propranolol, while treatment with PTU (6-n-propyl-2-thiouracil) increased adenosine sensitivity in the isolated heart. It was concluded that the levels of A₁ adenosine receptors in the heart correspond to heart rate, and to cardiac efficiency. While an increase in heart rate was followed by up-regulation of A₁ adenosine receptors, a decrease in heart rate caused a moderate elevation of these receptors.     

Development of in vitro embryo production systems for red deer (Cervus elaphus). Part 3. In vitro fertilisation using sheep serum as a capacitating agent and the subsequent birth of calves

The following experiments investigated the use of sheep serum (SS) as a capacitating agent for red deer (Cervus elaphus) sperm during in vitro fertilisation. Red deer oocytes were collected at slaughter and matured in vitro for 24h in TCM-199 supplemented with 10% foetal calf serum, 10 microg ml(-1) FSH and LH, and 1microg ml(-1) of oestradiol. Fertilisation medium was IVF-SOF modified to contain 5mM Ca(2+) and no glucose. Experiment 1 investigated the addition of heparin, BSA (8 mg ml(-1)) or 20% SS. All oocytes were penetrated when IVF-SOF was supplemented with SS compared to 10 and 0% penetration when either heparin or BSA was present (P<0.01). However, 43.8% of these oocytes were polyspermic when the medium contained SS. In Experiment 2, the effect of sperm concentration on penetration rates during in vitro fertilisation was investigated. Total sperm penetration and monospermic penetration rates increased with increased sperm concentrations in a log linear manner (P<0.001) and both approached an asymptote at 0.4 x 10(6) sperm ml(-1) with 93.6 and 77% for total and monospermic penetration, respectively. Polyspermic fertilisation also increased with increasing sperm concentrations (P<0.05) but was variable (range 3.5+/-4.2 to 42.3+/-10.6%), especially at the lower sperm concentrations. Experiment 3 investigated the viability of these oocytes after transfer into red deer recipients. Fifteen 2- and 4-cell embryos were transferred into the oviducts of synchronized recipients 28 h post in vitro insemination. An additional fourteen embryos (8-10 cell) were transferred into synchronised recipients after 48 h of in vitro culture in either SOFaaBSA (n=10) or on red deer epithelial oviduct monolayers (n=4). Five (33% 5/15) of the recipients that received 2- and 4-cell embryos were pregnant at Day 45 (verified by ultrasonography) and four recipients subsequently calved. One recipient receiving an embryo cultured in SOFaaBSA was pregnant at Day 45 and subsequently calved. The birth of five normal calves indicate that full developmental competence of red deer oocytes matured and fertilised in vitro can be achieved by the techniques described.