Some chemical and physical characteristics of the semen of Cyprinus carpio L. and Oreochromis mossambicus (Peters)

The chemical and physical characteristics of the semen of Cyprinus carpio and Oreochromis mossambicus were investigated on a comparative and seasonal basis. Results were obtained for the volume, colour and viscosity of the semen, the percentage live spermatozoa, sperm concentrations and the degree and the duration of sperm motility under different environmental conditions. All showed distinct interspecific and less conspicuous seasonal intraspecific differences. Values have also been determined for the organic and inorganic components and the pH and osmolality of the seminal fluid. Some inorganic and organic components indicated seasonal intraspecific differences while all the components, with the exception of sodium and galactose, indicated significant interspecific differences. These observations suggest significant interspecific differences in the testicular secretions of the two fish species which add to the basic physiological differences recorded for the spermatozoa of C. carpio and O. mossambicus . The probable function of the carbohydrates, protein and enzymes present in the semen of these fish species are discussed.     

Sexual maturity and physical exercise alter fibrinolytic activity in birds (chickens)

1. Sexual maturity in the domestic hen is accompanied by hyperlipidaemia. This study examined effects of hyperlipidaemia on fibrinolytic activity at rest and following prolonged treadmill exercise. 2. In immature hens the mean pooled-plasma fibrinolytic activity was 50 mm2 and following 90 min continuous exercise this rose to 114 mm2. In contrast, fibrinolytic activity in mature hens was undetectable but rose to 51 mm2 after exercise. 3. The fibrinolytic response of mature and immature cocks was comparable to that of the immature hens. 4. The resting plasma triglyceride concentration in mature hens was approximately seven times that of the immature hens, immature and mature cocks. Exercise induced significant increases in plasma non-esterified fatty acid concentrations but had no significant effect on triglyceride or cholesterol levels. 5. The results demonstrate that prolonged exercise in birds, as in man, evokes hyperfibrinolysis. However, the response is impaired in mature females and this may be associated with increased blood lipid levels.     

Effect of physical and chemical conditions on the production of colominic acid by Escherichia coli in a defined medium

Summary A chemically defined medium capable of supporting the growth of Escherichia coli K-235 and optimal for colominic acid (poly-N-acetylneuraminic acid) production has been developed. When the culture was incubated at 37° C for 72 h in 250-ml shake flasks at 250 rpm (in a Gallenkamp incubator IRN-200; orbital diameter 32 mm), the highest polymer level (about 1,350 g ml^-1) was obtained in a minimal medium in which D-xylose and L-proline were the only carbon and nitrogen sources. The optimal pH range for its production (7.6–8.0) was maintained by buffering the medium with 80 mM KH₂PO₄/Na₂HPO₄ and the best aeration ratio was 4:1 (volume flask:volume medium). In these conditions high colominic acid biosynthetic activity was detected in the early logarithmic phase and was maximal in 19-h-old cells (A_{540 nm}=4.0). However, the release of polysialic acid into the broth started when growth stopped, showing kinetics typical of a secondary metabolite. The biosynthesis of this polymer was seen to be strictly temperature regulated.     

Neurophpophysial hormones and the emission of semen in rabbits.

To elucidate the importance of the neurohypophysial hormones for the emission of semen, several neurohypophysial peptides were tested in male rabbits and the sperm density in the ejaculates was determined. Besides oxytocin and vasopressin, vasotocin and one oxytocin analogue (de-amino1-oxytocin) were used. Only vasopressin, in a dose as low as 10 mU, increased the number of spermatozoa in the ejaculates. It is suggested that vasopressin is of physiological significance for the emission of semen, at least in rabbits.     

Genetic evaluation for semen characteristics in a crossbreeding project involving Saudi and Spanish V-line rabbits

Two parallel schemes of crosses were practised involving the Spanish maternal line called V-line (V) and Saudi Gabali (S) rabbits. The first scheme began by crossing Saudi Gabali bucks with V-line does to get the F₁ cross (½S½V), then does of this F₁ were backcrossed with bucks of V-line to get ¾V¼S, then the progenies of the backcross were inter se mated to get (¾V¼S)², followed by two more generations of inter se mating of (¾V¼S)² to get a new synthetic maternal line named Saudi 2. The second scheme began by crossing V-line bucks with Saudi does to get the F₁ cross (½V½S), then does of this F₁ cross were backcrossed with Saudi bucks to get ½S½V, then progeny of this backcross were inter se mated to get (¾S¼V)², followed by two generations of inter se mating of (¾S¼V)² to form a new synthetic paternal line named Saudi 3. A generalised least-square procedure was used to estimate differences between lines in direct and maternal additive effects, direct and maternal heterosis, and direct recombination losses. A total number of 2497 ejaculates of 642 bucks were evaluated for ejaculate volume (VE), pH of semen, sperm concentration (SC), percentage of motile spermatozoa (MS), percentage of spermatozoa with abnormal form (AS), percentage of dead spermatozoa (DS) and libido score (LS). The estimates of direct additive effect for DS (14.2%), SC (12.4%) and AS (12.0%) were moderate and favourable to Saudi rabbits. Maternal additive effects for VE (11.7%) were in favour of genes of V-line carried by the dams of bucks, while these estimates were in favour of Saudi genes for DS (18.6%), AS (13.2%), MS (10.8%) and SC (10.0%). Positive estimates of direct heterosis recorded for SC (13.5%), VE (10.6%) and MS (10.5%) and the negative estimates recorded for AS (−21.5%) and DS (−20.3%) were moderate and well disposed to semen parameters of crossbred bucks. Positive estimates of maternal heterosis for VE (24.0%), MS (21.8%), SC (10.3%) and LS (10.2%) of bucks, and the negative estimates for percentage of DS (−14.7%) and AS (−9.6%) were also significantly favourable. Estimates of direct recombination losses for the majority of semen traits were always not significant.     

PGR-08理化性质及生物活性的研究

PGR-0 8是从某种土壤放线菌 (Actinomyces)的发酵液中分离提纯得到的白色结晶 ,纸层析和熔点检测证明它是化学单体 ,mp 1 80～ 1 81℃ ,[α]2 1D+ 4 3°(H2 O)。溶解性试验表明它易溶于 H2 O(≥ 6 0℃ )、HCl、Na OH、(CH3 ) 2 CO、CH3 OH和 C2 H5OH等 ,但不溶于 Na HCO3 。Tollen、Fehling和 Ag NO3 -溴酚兰等专性试剂的颜色反应表明其组成成分中有嘌呤和糖。生物试验证明 :PGR-0 8具有细胞分裂素的活性 ,例如它能减缓蒲公英离体叶圆片 Chl.的降解 ,延长叶圆片寿命 1～ 2倍以上 ,诱导叶圆片分化出不定根或不定芽 ,甚至建成小植株。它还能促进小麦种子萌发。     

Antibodies to semen diluent and infertility in rabbits

Parenteral immunization with semen, with Nagase egg-yolk diluent (NEYD) or with semen in NEYD depressed fertility in does artificially inseminated with semen in NEYD. Although fertilization rates were significantly reduced in the animals which had been immunized with semen alone (P < 0.05) or with diluent alone (P < 0.05), the greatest reduction occurred in the animals which had been immunized with semen plus diluent (P < 0.01). Both the anti-semen antibodies and the anti-diluent antibodies contributed to the reduction in fertility of the animals which had been immunized with semen plus diluent.     

Some physical and chemical characteristics of an arctic beaded stream

Imnavait Creek is a tundra stream in the Arctic Foothills of Alaska. The stream is beaded, i.e. consists of pools (up to ∼ 2 m deep) connected by narrow channels. Peat dominates pool and channel substrate materials with occasional rock and moss substrates. The watershed is underlain by ice-bonded till and is hydrologically watertight. Because of low rates of weathering, bedrock and till do not contribute significantly to ionic composition of the stream water. Breakup occurs in late May to early June with surface flow until September. During periods of low rainfall, channel flow is reduced and pools become hydrologically isolated and thermally stratified (with very high surface water temperatures). Streamwater is acidic (pH values 5.3–6.1) with very low alkalinity (≤3 mg l⁻¹). The major transport of ions occurs in early flow derived from snow melt. Organic carbon concentrations are high with very high ratios of dissolved to particulate organic carbon. Dissolved inorganic nitrogen concentrations appear to be very low. High concentrations of dissolved organic material may indicate a central role for DOM in trophic dynamics.     

Ontogenetic variation in chemical and physical characteristics of adaxial apple leaf surfaces

The reaction of plants to environmental factors often varies with developmental stage. It was hypothesized, that also the cuticle, the outer surface layer of plants is modified during ontogenesis. Apple plantlets, cv. Golden Delicious, were grown under controlled conditions avoiding biotic and abiotic stress factors. The cuticular wax surface of adaxial apple leaves was analyzed for its chemical composition as well as for its micromorphology and hydrophobicity just after unfolding of leaves ending in the seventh leaf insertion. The outer surface of apple leaves was formed by a thin amorphous layer of epicuticular waxes. Epidermal cells of young leaves exhibited a distinctive curvature of the periclinal cell walls resulting in an undulated surface of the cuticle including pronounced lamellae, with the highest density at the centre of cells. As epidermal cells expanded during ontogenesis, the upper surface showed only minor surface sculpturing and a decrease in lamellae. With increasing leaf age the hydrophobicity of adaxial leaf side decreased significantly indicated by a decrease in contact angle. Extracted from plants, the amount of apolar cuticular wax per area unit ranged from only 0.9 microgcm(-2) for the oldest studied leaf to 1.5 microgcm(-2) for the youngest studied leaf. Differences in the total amount of cuticular waxes per leaf were not significant for older leaves. For young leaves, triterpenes (ursolic acid and oleanolic acid), esters and alcohols were the main wax components. During ontogenesis, the proportion of triterpenes in total mass of apolar waxes decreased from 32% (leaf 1) to 13% (leaf 7); absolute amounts decreased by more than 50%. The proportion of wax alcohols and esters, and alkanes to a lesser degree, increased with leaf age, whereas the proportion of acids decreased. The epicuticular wax layer also contained alpha-tocopherol described for the first time to be present also in the epicuticular wax. The modifications in the chemical composition of cuticular waxes are discussed in relation to the varying physical characteristics of the cuticle during ontogenesis of apple leaves.     

Pellet-freezing of Damascus goat semen in a chemically defined extender

During the breeding season of goats (12 bucks and 64 does) in Egypt, five experiments were conducted using a chemically defined cryoextender (CDE) to investigate: (1) the influence of rates of semen dilution (1:2, 1:4 and 1:19) and methods of thawing of frozen semen pellets (dry thawing versus wet thawing) on sperm progressive motility (SPM), sperm acrosome abnormalities (SAA) and rate of lipid peroxidation in semen as measured by malonaldehyde (MAL) production, and (2) the effect of insemination of does in natural (n = 38) and cloprostenol-synchronized (n = 26) estrus with frozen semen on their kidding rates and prolificacy. Semen (two successive ejaculates/buck) was collected twice a week via an AV and only ejaculates of >2500 x 10(6) sperm/ml and 70% SPM were diluted in one step at 30 degrees C with the CDE, cooled to 5 degrees C over a 4h-period, frozen in the form of 0.30 ml pellets and stored in liquid nitrogen for 72 h. The results revealed that post-thaw SPM of semen diluted at a rate of 1:4 was significantly (P < 0.01) higher than that of semen diluted at the other rates. Dilution of semen at a rate of 1:19 (< or =151 x 10(6) sperm/ml) not only minimized (P < 0.01) pre-freeze and post-thaw SPM, but also augmented (P < 0.01) pre-freeze and post-thaw rates of lipid peroxidation as evidenced by the high level of MAL production and the ability of antioxidants (1mg/ml EDTA, 200 U/ml bovine liver catalase, 0.61 mg/ml reduced glutathione and 0.11 mg/ml sodium pyruvate) to restore (P < 0.01) pre-freeze and post-thaw SPM. Frozen semen pellets exposed to dry thawing had a greater percentage of SPM (P < 0.01) as well as lower values of SAA and MAL (P < 0.01) than those exposed to wet thawing. Although the kidding rates did not vary significantly among does in natural (55.26%) and synchronized (53.85%) estrus, a higher (P < 0.05) prolificacy was obtained after their insemination in natural (1.81+/-0.16) rather than in synchronized (1.22+/-0.11) estrus.     

Changes in the chemical characteristics of water-extractable organic matter during composting and their influence on compost stability and maturity

Composting is the biochemical transformation of waste organic matter by microorganisms whose metabolism occurs in the water-soluble phase. Therefore, a study of the changes occurring in compost dissolved organic matter can be useful for assessing its stability and maturity. In light of the variety of parameters generally utilized to study composting processes, this work aims at identifying the major chemical processes that occur in solution and their influence on the attainment of stability and maturity with composting time. Compost stability, assessed by means of respirometric analysis which determined oxygen demand as a result of mineralization of the compost's organic matter, and compost maturity evaluated with Lepidium sativum L. seed bioassays, were found to be highly related to the nature and content of water-soluble organic matter. Moreover, fractionation of the water-extractable organic carbon showed that the ratio of hydrophobic to hydrophilic carbon increased to values greater than unity for stabilized compost. These results together with the analysis for non-cellulosic polysaccharides, phenolic compounds and organic nitrogen within the water extracts, confirmed the influence of solubilization, mineralization and organic matter transformation on the quality of the final compost.     

Sexual maturity and breeding season of the badger, Meles meles in Sweden

The paper describes the seasonal sexual activity of badgers collected in central Sweden. Ovulation- and pregnancy rates were determined for females in different age classes and males were examined for testis weight and occurrence of spermatozoa.     

Sexual maturity and shape development in cranial appendages of extant ruminants

Morphological disparity arises through changes in the ontogeny of structures; however, a major challenge of studying the effect of development on shape is the difficulty of collecting time series of data for large numbers of taxa. A proxy for developmental series proposed here is the age at sexual maturity, a developmental milestone potentially tied to the development of structures with documented use in intrasexual competition, such as cranial appendages in Artiodactyla. This study tested the hypothesis that ruminant cranial appendage shape and size correlate with onset of sexual maturity, predicting that late sexual maturity would correlate with larger, more complicated cranial appendages. Published data for cranial appendage shape and size in extant taxa were tested for correlations with sexual maturity using linear mixed‐effect models and phylogenetic generalized least‐squares analyses. Ancestral state reconstructions were used to assess correlated variables for developmental shifts indicative of heterochrony. These tests showed that phylogeny and body mass were the most common predictors of cranial appendage shape and sexual maturity was only significant as an interaction with body mass. Nevertheless, using developmental milestones as proxies for ontogeny may still be valuable in targeting future research to better understand the role of development in the evolution of disparate morphology when correlations exist between the milestone and shape.