Sexual receptivity and post-emergence ovarian development in females of Coproica vagans (Diptera: Sphaeroceridae)

Abstract .Males and females of the dung fly species Coproica vagans Haliday 1833 (Diptera: Sphaeroceridae) mate soon after emergence from the puparium. At this time females still have immature ovaries. Therefore, mating precedes vitellogenesis in this species. Data presented here show that mating enhances oogenesis in C. vagans females. Mated females mature their first egg batch sooner and oviposit four days earlier than virgin conspecifics. Mating-related enhancement of oogenesis could be explained either through nutritional benefits to females or male chemical or stimulatory manipulation of the females. Oogenesis was divided into six arbitrary stages, with vitellogenesis beginning in stage 4. Ovarian development beyond stage 4 is rapid compared with pre-vitellogenetic development. Virgin females pause oogenesis in stage 4. The genital opening of mated females is blocked by a mating plug that persists until oviposition begins. The plug seems to ensure the paternity of the last male to mate by preventing females from remating. The operational sex ratio in C. vagans populations is presumed to be strongly male-biased.     

Pulmonary clearance of inhaled 99mTc-DTPA: effects of surfactant depletion by lung lavage

The influence of surfactant depletion on clearance from the lungs of inhaled technetium-99m-labeled diethylenetriamine pentaacetate (99mTc-DTPA) was studied in rabbits. Surfactant was removed by repeated lung lavage with isotone saline. To minimize structural damage to the lungs, pressure generated insufflation with short expiration was utilized. Aerosolized 99mTc-DTPA was administered via a bag-in-bottle system. Radioactivity was measured with a gamma camera and time-activity curves were obtained over the base of the right lung. Six nonlavaged rabbits served as controls. In six lavaged rabbits clearance of 99mTc-DTPA was significantly faster than in controls. In three rabbits given natural surfactant into the trachea after lung lavage, 99mTc-DTPA was eliminated faster than in controls but slower than in surfactant-depleted animals. The results indicate a role of surfactant on clearance rate of 99mTc-DTPA from rabbit lungs. Measurements of 99mTc-DTPA clearance may be useful in studying the function of the surfactant system in different lung disorders.     

Dynamic resource allocation between pre- and postcopulatory episodes of sexual selection determines competitive fertilization success

In polyandrous mating systems, male reproductive success depends on both mate-acquisition traits (precopulatory) and sperm competitive abilities (postcopulatory). Empirical data on the interaction between these traits are inconsistent; revealing positive, negative or no relationships. It is generally expected that the investment in pre- and postcopulatory traits is mediated by environmental conditions. To test how dietary resource availability affects sexual ornamentation, sperm quality and their interrelationship in three-spined sticklebacks (Gasterosteus aculeatus), full-sibling groups were raised under three conditions differing in food quantity and/or quality (i.e. carotenoid content): (i) high-quantity/high-quality, (ii) high-quantity/low-quality or (iii) low-quantity/low-quality. After 1 year of feeding, food-restricted males developed a more intense breeding coloration and faster sperm compared with their well-fed brothers, indicating that they allocated relatively more in pre- and postcopulatory traits. Moreover, they outcompeted their well-fed, carotenoid-supplemented brothers in sperm competition trials with equal numbers of competing sperm, suggesting that food-restricted males maximize their present reproductive success. This may result in reduced future reproductive opportunities as food-restricted males suffered from a higher mortality, had an overall reduced body size, and sperm number available for fertilization. In accordance with theory, a trade-off between the investment in pre- and postcopulatory traits was observed in food-restricted males, whereas well-fed males were able to allocate to both traits resulting in a significantly positive relationship.     

Bovine conglutinin is a collagen-like protein

Conglutinin is a bovine plasma protein which is relatively large and asymmetric with elevated contents of glycine and, to some extent, proline. Although its physiologic function is unknown, conglutinin is known to bind, in the presence of calcium, to yeast cell walls and to the solid-phase-inactivated third component of complement. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, isolated conglutinin appeared to consist of a single polypeptide chain (Mr 48 000). Unreduced conglutinin consisted of a single stained band with an apparent molecular weight of approximately 300 000. Cross-linking experiments with glutaraldehyde and dimethyl suberimidate suggested that this Mr 300 000 molecule consists of six of the disulfide-linked polypeptide chains. Amino acid composition revealed hydroxylysine and hydroxyproline together with elevated glycine and proline contents. Digestion of reduced, alkylated conglutinin with bacterial collagenase resulted in formation of a precipitate which consisted of an Mr 24 000 peptide which was digested to Mr 21 000 with large quantities of collagenase. These peptides contained less glycine, proline, hydroxylysine, and hydroxyproline than did the intact protein. The supernatant from this digestion mixture was, however, enriched in these four amino acids, with glycine making up nearly one-third of the total. Prolonged digestion with pepsin at 37 degrees C resulted in an Mr 20 000 peptide which was enriched in glycine, proline, hydroxyproline, and hydroxylysine. Amino-terminal sequence analysis showed that the glycine-X-Y repeating sequence begins at residue 26.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enhancing the structural diversity between forest patches—A concept and real-world experiment to study biodiversity,multifunctionality and forest resilience across spatial scales

Intensification of land use by humans has led to a homogenization of landscapes and decreasing resilience of ecosystems globally due to a loss of biodiversity, including the majority of forests. Biodiversity–ecosystem functioning (BEF) research has provided compelling evidence for a positive effect of biodiversity on ecosystem functions and services at the local (α-diversity) scale, but we largely lack empirical evidence on how the loss of between-patch β-diversity affects biodiversity and multifunctionality at the landscape scale (γ-diversity). Here, we present a novel concept and experimental framework for elucidating BEF patterns at α-, β-, and γ-scales in real landscapes at a forest management-relevant scale. We examine this framework using 22 temperate broadleaf production forests, dominated by Fagus sylvatica. In 11 of these forests, we manipulated the structure between forest patches by increasing variation in canopy cover and deadwood. We hypothesized that an increase in landscape heterogeneity would enhance the β-diversity of different trophic levels, as well as the β-functionality of various ecosystem functions. We will develop a new statistical framework for BEF studies extending across scales and incorporating biodiversity measures from taxonomic to functional to phylogenetic diversity using Hill numbers. We will further expand the Hill number concept to multifunctionality allowing the decomposition of γ-multifunctionality into α- and β-components. Combining this analytic framework with our experimental data will allow us to test how an increase in between patch heterogeneity affects biodiversity and multifunctionality across spatial scales and trophic levels to help inform and improve forest resilience under climate change. Such an integrative concept for biodiversity and functionality, including spatial scales and multiple aspects of diversity and multifunctionality as well as physical and environmental structure in forests, will go far beyond the current widely applied approach in forestry to increase resilience of future forests through the manipulation of tree species composition.     

Order of bovine DRB3, DYA,and PRL determined by sperm typing

The order and recombination fractions () between the bovine major histocompatibility complex DRB3, DYA, and prolactin (PRL) genes were determined by typing of 254 sperm from a triply heterozygous bull. A recently developed method, primer extension preamplification (PEP), was used to amplify the bovine sperm genome prior to amplification of specific loci by the polymerase chain reaction (PCR). At least 28 copies of the DRB3, PRL, or DYA gene were obtained from 50 cycles of PEP. For sperm typing, alleles of each locus were discriminated by restriction endonuclease cleavage of PCR products and polyacrylamide gel electrophoresis of the restriction fragments. The most likely gene order is PRL-DRB3-DYA, with =0.025 (±0.012) and =0.150 (±0.024), respectively. The odds are 128:1 in favor of this order in comparison with the second most likely order DRB3-PRL-DYA. Our results demonstrate the power of sperm typing in concert with PEP for multilocus gene mapping.     

Direct molecular analysis of the fragile X syndrome in a sample of Egyptian and German patients using non-radioactive PCR and Southern blot followed by chemiluminescent detection

Molecular genetic analysis of individuals from 6 Egyptian and 33 German families with fragile X syndrome and 240 further patients with mental retardation was performed applying a completely non-radioactive system. The aim of our study was the development of a non-radioactive detection method and its implementation in molecular diagnosis of the fragile X syndrome. Furthermore, we wanted to assess differences in the mutation sizes between Egyptian and German patients and between Egyptian and German carriers of a premutation. Using non-radioactive polymerase chain reaction (PCR), agarose gel electrophoresis and blotting of the PCR products, followed by hybridisation with a digoxigenin-labelled oligonucleotide probe (CGG)₅ and chemiluminescent detection, we identified the fragile X full mutation (amplification of a CGG repeat in the FMR-1 gene ranging from several hundred to several thousand repeat units) in all patients. We observed no differences in the length of the CGG repeat between the Egyptian and German patients and carriers, respectively. However, in one prenatal diagnosis, we detected only one normal sized allele in a female fetus using the PCR-agarose assay, whereas Southern blot analysis with the digoxigenin labelled probe StB 12.3 revealed presence of a full mutation. Our newly established nonradioactive genomic blotting method is based on the conventional radioactive Southern blot analysis. Labelling of the probe StB 12.3 with digoxigenin via PCR allowed the detection of normal, premutated and fully mutated alleles. For exact sizing of small premutated or large normal alleles, we separated digoxigenin labelled PCR products through denaturing poly-acrylamide gelelectrophoresis (PAGE) and transfered them to a nylon membrane using a gel dryer. The blotted PCR-fragments can easily be detected with alkaline phosphate-labelled anti-digoxigenin antibody. The number of trinucleotide repeat units can be determined by scoring the detected bands against a digoxigenated M13 sequencing ladder. Our newly developed digoxigenin/chemiluminescence approach using PCR and Southern blot analysis provides reliable results for routine detection of full fragile X mutations and premutations.     

Activation of complement by Schistosoma mansoni schistosomula: killing of parasites by the alternative pathway and requirement of IgG for classical pathway activation.

Living Schistosoma mansoni schistosomula incubated with normal chicken, guinea pig, human, and monkey sera were killed after 4 hr contact at 37 degrees C. The following data indicate that this action is dependent on the activation of the alternative complement pathway (AP): a) the inactivity of RB, RD, and zymosan-treated serum against schistosomula; b) the partial activity of RD restored in FD; c) the full effect of the C4-deficient guinea pig, C2-deficient human, and the agammaglobulinemic human sera; d) the consumption of both the AP and FB after the incubation of NHS with schistosomula; e) the detection of C3d breakdown product during the contact of the C2-deficient human serum with these young parasites. Killing by serum was decreased as the immature schistosomes developed and was completely absent against 4-day-old lung schistosomula (LS). In other experiments, it was demonstrated that schistosomula, in the presence of IgG, were able to initiate complement activation also through the classical pathway (CP). However, the CP does not appear to play a role in the schistosomulicidal activity of complement. The in vivo relevance of these observations is considered.     

Chick Nutrition and Mortality in Captive Willow Ptarmigan (Lagopus L. Lagopus)

Willow ptarmigan chicks were reared during 8 years on concentrates supplemented with blueberry plants. Mortality during the first 3 weeks after hatching ranged between 33 and 65 %, and was mainly caused by enteritis and digestive tract obstructions. The annual variations in chick survival seemed to be caused by the variations in plant phenology. The survival was highest when spring and blueberry plant development was late, and lowest when spring was early and warm, leading to early lignification of blueberry plant leaves.     

Activation of the alternative complement pathway by lymphoblastoid cell lines derived from patients with Burkitt's lymphoma and infectious mononucleosis.

Cultured human lymphoblastoid cell lines derived from patients with Burkitt's lymphoma or infectious mononucleosis were shown to activate the alternative pathway of complement fixation. This reaction does not require any conventional antibody directed against the cells. Although the reaction showed an absolute dependence on the presence of factor B it was relatively independent of the presence of factor D or of properdin. To this extent activation of the alternative pathway by lymphoblastoid cells resembles that produced by “C3-nephritic factor.” Rat and mouse complement were activated in a manner similar to human complement, but guinea pig complement was inactive. Chicken complement, unlike any of the mammalian complements tested, was able to bring about lysis of the lymphoblastoid cell lines by the alternative pathway.