Sexual behavior of donkey jacks: influence of ejaculatory frequency and season

The courtship of 5 jacks was evaluated weekly for 12 mo. The characteristics of sexual behavior were recorded before the collection of 2 ejaculates, at 4-h intervals, into an artificial vagina in the presence of a female in either natural or induced estrus. The maximum time given to the jack to perform the ejaculatory mount was 1 h. If the jacks did not ejaculate, another attempt was made the following week. At the time of collection, the male and female remained free in a paddock (20 m2). The data presented in this study is based on results in which the first and second ejaculates occurred successively. Statistical analysis was done by a 2 x 2 factorial design in randomized blocks. The mean +/- SEM of sexual behavior characteristics for the first and second ejaculate were, respectively: time until first mount = 0.7 +/- 0.2 and 0.9 +/- 0.2 min; time until first erection = 11.9 +/- 1.1 and 11.6 +/- 1.1 min; time until ejaculation = 15.0 +/- 1.2 and 13.6 +/- 1.2 min; frequency of partial exposure of penis = 3.4 +/- 0.4 and 3.2 +/- 0.4; frequency of total exposure of penis = 1.0 + 0.2 and 1.1 +/- 0.2; frequency of flehmen responses = 6.6 +/- 0.5 and 4.6 +/-0.5; frequency of erections = 1.3 +/- 0.1 and 1.2 +/- 0.1; frequency of retreats away from the female = 1.8 +/- 0.2 and 1.0 +/- 0.2; frequency of mounts with erection but without ejaculation = 0.3 +/- 0.1 and 0.1 +/- 0.1; frequency of mounts without erection = 2.0 +/-0.1 and 1.2 +/- 0.1 ; and frequency of pelvic copulatory movements = 4.8 +/- 0.4 and 4.4 +/- 0.4. Individual differences were observed (P<0.05) for partial and total exposure, flehmen responses, mounts without erection and pelvic copulatory movements. The variables flehmen responses, retreats away from the female and mounts without erection showed significant differences (P<0.05) between ejaculates. Seasonal effects on sexual behavior characteristics were not found. However, a monthly effect was noted for flehmen responses, partial exposure of the penis, mounts without erection, retreats away from the female and pelvic copulatory movements when the 2 ejaculates were combined.     

Advantages of the scanning ion microscopy for mapping halogen corticoids in normal and transformed cells in culture

Summary— The intra-cellular distribution of eight halogen glucocorticoids was investigated by ion microscopy in two cellular varieties of cultured non-cancer cells (fibroblast 3T3) and cancer cells (human breast tumor cells MCF-7). Two types of ion microscopy helped to determine this distribution, a direct imaging ion microscope (SMI 300) with low spatial resolution, and a scanning ion microscope (IMS4F), featuring high resolution, serving to obtain maps representing the intra-cellular distribution of the fluorine elements and drugs present in these monolayer cultured cells. The fluorine images representative of the drugs containing fluorine showed that these drugs are essentially concentrated in the cell nuclei. In these nuclei, the distribution of these drugs is different from that of heterochromatin and of the nucleolus.     

Regulation of μ-Opioid Receptor mRNA in Rat Globus Pallidus: Effects of Enkephalin Increases Induced by Short- and Long-Term Haloperidol Administration

Abstract: The mRNA encoding μ-opioid receptors is expressed in neurons of the globus pallidus, a region of the basal ganglia that receives a dense enkephalinergic innervation from the striatum. The regulation of the mRNAs encoding the opioid peptide enkephalin in the striatum and the μ-opioid receptor in the globus pallidus was examined with in situ hybridization histochemistry following short- or long-term haloperidol treatments, which alter striatal enkephalin mRNA levels. Animals were administered haloperidol daily for 3 or 7 days (1 mg/kg, s.c.) or continuously for 8 months (1 mg/kg, depot followed by oral). Enkephalin and μ-opioid receptor mRNA levels were unchanged after 3 days of haloperidol treatment. In contrast, the enkephalin mRNA level was increased in the striatum, and μ-opioid receptor mRNA levels were markedly decreased in the globus pallidus after 7 days of haloperidol administration. Similar effects were observed in rats treated with haloperidol for 8 months. The results provide the first evidence of regulation of μ-opioid receptor mRNA in vivo.     

Culture analysis and external interaction models of mycelial growth

To investigate morphogenesis and in particular circularization mechanisms in young mycelia, we observe cultures of the zygomyceteMucor spinosus and develop discrete models of two-dimensional filamental branching growth. The models are based on the hypothesis that the fungus secretes a regulatory substance that diffuses into the surrounding medium and is detected by the growing hyphae. We also present a simple Markovian growth model without such a feedback, but yielding to analytical computations.     

A protein involved in co-ordinated regulation of inorganic carbon and glucose metabolism in the facultative photoautotrophic cyanobacteriumSynechocystis PCC6803

The involvement of a gene ofSynechocystis PCC6803,icfG, in the co-ordinated regulation of inorganic carbon and glucose metabolism, was established. TheicfG gene codes for a 72 kDa protein, which shows no homology with those registered in data libraries. Expression oficfG required glucose, the actual inducer probably being glucose-6-phosphate, and was independent of light and of the external inorganic carbon concentration. Mutants carrying an inactivated copy oficfG were constructed. Their growth characteristics were identical to those of the wild type under all regimes except in limiting inorganic carbon with glucose being present either before or after the transfer to the limiting conditions. These conditions completely prevented growth, both in the light and in the dark. The inhibition could be relieved by several intermediates of the tricarboxylic acid cycle. Assays of various enzymic activities related to inorganic carbon uptake and to its assimilationvia either the Calvin cycle or phosphoenolpyruvate carboxylase did not reveal the level of action of IcfG. Possible models include a blockage of the assimilation of both carbon sources in the absence of IcfG, or the inhibition of Ci incorporation route(s) essential under limiting inorganic carbon conditions, even when glucose is present, and even in the dark.     

Determination of the kinetic parameters in continuous cultivation byDebaryomyces hansenii grown on D-xylose

Summary The kinetic parameters of the yeastDebaryomyces hansenii grown in continous cultivation on D-xylose were determined by different methods. While the values obtained for μ_m by the steady state and the washout methods only gave a 3% difference, the determined K_s values by the steady state and the maximal biomass output methods led a to a 305% difference. The latter method was suggested to overestimate the K_s value.     

Skewed inactivation of an X chromosome deleted at the dystrophin gene in an asymptomatic mother and her affected daughter

A girl with severe Becker muscular dystrophy and apparently normal chromosomes had a heterozygous deletion for exons 51, 52, and 53 of the dystrophin gene. This deletion was transmitted by her mother, who was unaffected. To differentiate the normal and the deleted X chromosomes, fluorescence in situ hybridization (FISH) was applied to metaphase chromosomes, using probes for both exons 51 and 52, which are only 388 and 113 base pairs long, respectively. FISH signals were observed in one or both chromatids of one chromosome, but never on both chromosomes, suggesting the lack of hybridization on the deleted X chromosome. Using 5-bromodeoxyuridine incorporation to differentiate the late (inactive) and the early replicating (active) X chromosomes, 77% of the signals were observed on the active X chromosomes in the mother. This percentage was only 18% in the daughter, suggesting that skewed inactivation of the X chromosomes was responsible for the phenotypic differences.     

Importance of fungi in the diet of Gammarus pulex and Asellus aquaticus

An important component of the interaction between macroinvertebrates and leaf litter in streams in the extent to which consumers can differentiate between undecomposed and decomposing leaves. The detritivores Gammarus pulex and Asellus aquaticus fed preferentially on conditioned rather on unconditioned leaf material. Growth in A. aquaticus was significantly reduced when unconditioned leaves were provided, but in G. pulex no significant effect of conditioning on growth was observed. The capacity of G. pulex to tolerate reductions in food quality seems to be a consequence of a compensatory system in which respiration rates change to compensate for reductions in food quality. In this way a constant growth rate is maintained. Increases in ingestion rates to compensate for low quality food were not observed.     

Cobalt determination in serum and urine by electrothermal atomic absorption spectrometry

Cobalt determinations in biological fluids are of great interest in biological or toxicological research programs. Cobalturia is often chosen as an indicator for a biological monitoring program in occupational exposure to cobalt dusts. The method described here derives from the IUPAC reference method for nickel determination. It enables cobaltemia and cobalturia to be measured in small samples (1 mL). The mean usual values for cobalt in biological fluids are very low (2.7 nmol L⁻¹ for serum and 6.7 nmol L⁻¹ for urine), and therefore, thus require an analytical procedure with preconcentration and extraction. The sample is mineralized by wet acid digestion. After digestion, inorganic cobalt is extracted in form of ammonium pyrrolidine dithiocarbamate complex into isobutyl methyl ketone and measured in the organic layer by electrothermal atomic absorption spectrometry. The analytical parameters are described in detail. The extraction output is about 99%. The detection limits are 1.93 and 1.89 nmol L⁻¹ for serum and urine, respectively. Sensitivity (expressed as the concentration that gives a 0.044 absorbance) is 3.4 nmol L⁻¹ for serum and 3.3 nmol L⁻¹ for urine. Within-run precision ranged between 3.9 and 2.5% (coefficients of variation) for serum and 4.2 and 1.1% for urine, at 87 and 136 nmol L⁻¹ levels, respectively. Between-run precision ranged between 4.3 and 3.3% (coefficients of variation) for serum and 4.2 and 2.3% for urine, at 87 and 136 nmol L⁻¹ levels, respectively. At very low concentration, 5.7 nmol L⁻¹ for serum and 2.5 nmol L⁻¹ for urine, the between-run precision is, respectively, 19.5 and 28%. Linearity is effective between 0 and 272 nmol L⁻¹. Interferences and matrix effects are negligible for urine, serum, or plasma samples without hemoglobin. The method is easily applicable for routine determinations.