Male Seminal Fluid Substances Affect Sperm Competition Success and Female Reproductive Behavior in a Seed Beetle

Male seminal fluid proteins are known to affect female reproductive behavior and physiology by reducing mating receptivity and by increasing egg production rates. Such substances are also though to increase the competitive fertilization success of males, but the empirical foundation for this tenet is restricted. Here, we examined the effects of injections of size-fractioned protein extracts from male reproductive organs on both male competitive fertilization success (i.e., P2 in double mating experiments) and female reproduction in the seed beetle Callosobruchus maculatus. We found that extracts of male seminal vesicles and ejaculatory ducts increased competitive fertilization success when males mated with females 1 day after the females’ initial mating, while extracts from accessory glands and testes increased competitive fertilization success when males mated with females 2 days after the females’ initial mating. Moreover, different size fractions of seminal fluid proteins had distinct and partly antagonistic effects on male competitive fertilization success. Collectively, our experiments show that several different seminal fluid proteins, deriving from different parts in the male reproductive tract and of different molecular weight, affect male competitive fertilization success in C. maculatus. Our results highlight the diverse effects of seminal fluid proteins and show that the function of such proteins can be contingent upon female mating status. We also document effects of different size fractions on female mating receptivity and egg laying rates, which can serve as a basis for future efforts to identify the molecular identity of seminal fluid proteins and their function in this model species.     

Intracytoplasmic Sperm Injection Using DNA-Fragmented Sperm in Mice Negatively Affects Embryo-Derived Embryonic Stem Cells,Reduces the Fertility of Male Offspring and Induces Heritable Changes in Epialleles

Intracytoplasmic sperm injection (ICSI) in mice using DNA-fragmented sperm (DFS) has been linked to an increased risk of genetic and epigenetic abnormalities both in embryos and offspring. This study examines: whether embryonic stem cells (ESCs) derived from DFS-ICSI embryos reflect the abnormalities observed in the DFS-ICSI progeny; the effect of DFS-ICSI on male fertility; and whether DFS-ICSI induces epigenetic changes that lead to a modified heritable phenotype. DFS-ICSI-produced embryos showed a low potential to generate ESC lines. However, these lines had normal karyotype accompanied by early gene expression alterations, though a normal expression pattern was observed after several passages. The fertility of males in the DFS-ICSI and control groups was compared by mating test. Sperm quantity, vaginal plug and pregnancy rates were significantly lower for the DFS-ICSI-produced males compared to in vivo-produced mice, while the number of females showing resorptions was higher. The epigenetic effects of DFS-ICSI were assessed by analyzing the phenotype rendered by the Axin1^Fu allele, a locus that is highly sensitive to epigenetic perturbations. Oocytes were injected with spermatozoa from Axin1^{Fu /+} mice and the DFS-ICSI-generated embryos were transferred to females. A significantly higher proportion of pups expressed the active kinky-tail epiallele in the DFS-ICSI group than the controls. In conclusion: 1) ESCs cannot be used as a model of DFS-ICSI; 2) DFS-ICSI reduces sperm production and fertility in the male progeny; and 3) DFS-ICSI affects the postnatal expression of a defined epigenetically sensitive allele and this modification may be inherited across generations.     

Mating Effort and Cryptic Sperm Choice in Scorpionflies: Male Investment Strategy vs. Female Control

In this study, we examined which sex controls sperm transfer during copulation in scorpionflies. Therefore male scorpionflies were doubly mated to females of high and low fecundity to explore whether they allocate sperm according to female quality. While mating order had no effect males transferred sperm at higher rates when mating with low‐quality instead of high‐quality females. As there is no obvious benefit from providing low‐fecundity females with more sperm, we suggest a condition‐dependent female ability to counteract sperm transfer. Therefore, we disabled females at the beginning of copulations using the insecticide Propoxur which leads to total paralysis caused by tremors. While the provoked muscle contractions led to significantly smaller numbers of sperm transferred, Propoxur treatment had no effect on males. We suggest female counteracting of sperm transfer to be adaptive by decreasing the relative amount of sperm transferred by low‐quality males and increasing the proportion of offspring sired by high‐quality males.     

Mitochondrial Membrane Potential and DNA Stainability in Human Sperm Cells: A Flow Cytometry Analysis with Implications for Male Infertility

Sperm cells from control donors of proven fertility and men from barren couples were studied by conventional procedures, i.e., light microscopy as well as flow cytometry. Light microscopy analysis of semen included the measurement of spermatozoa concentration, morphology, and motility. All the men from barren couples were asthenozoospermic at the conventional analysis of semen samples. Flow cytometry was applied to study two important parameters of sperm cells: mitochondrial membrane potential (MMP) assessed by the cationic dye JC-1 and DNA stainability with propidium iodide (PI). JC-1 staining was more reliable than the classical procedure used for this purpose, i.e., rhodamine 123 (Rh123) staining, and allowed us to show a positive correlation between MMP and spermatozoa motility. Regarding DNA analysis, a higher relative percentage of immature spermatozoa, showing a high accessibility of DNA to the intercalating PI fluorochrome, was found in men from barren couples compared to donors of proven fertility. The relative percentage of immature spermatozoa was significantly higher in semen from oligoasthenozoospermic subjects. Moreover, a positive correlation was found between immature spermatozoa, as evaluated by PI staining, and cells with depolarized mitochondria, as evaluated by JC-1 staining, suggesting that spermatozoa defective for nuclear maturity could be functionally defective cells. No correlation between immature spermatozoa determined by FCM and immature spermatozoa determined by light microscopy was found, suggesting that these two techniques assess sperm cell maturity at different levels.     

60-Day Chronic Exposure to Low Concentrations of HgCl2 Impairs Sperm Quality: Hormonal Imbalance and Oxidative Stress as Potential Routes for Reproductive Dysfunction in Rats

Mercury is a toxic and bio-accumulative heavy metal of global concern. While good deals of research have been conducted on the toxic effects of mercury, little is known about the mechanisms involved in the pathogenesis of male reproductive dysfunction induced by mercury. Therefore, the purpose of this study was to assess the effects and underlying mechanisms of chronic mercury exposure at low levels on male reproductive system of rats. Three-month-old male Wistar rats were divided into two groups and treated for 60 days with saline (i.m., Control) and HgCl₂ (i.m. 1^st dose: 4.6 µg/kg, subsequent doses 0.07 µg/kg/day). We analyzed sperm parameters, hormonal levels and biomarkers of oxidative stress in testis, epididymis, prostate and vas deferens. Mercury treatment decreased daily sperm production, count and motility and increased head and tail morphologic abnormalities. Moreover, mercury treatment decreased luteinizing hormone levels, increased lipid peroxidation on testis and decreased antioxidant enzymes activities (superoxide dismutase and catalase) on reproductive organs. Our data demonstrate that 60-day chronic exposure to low concentrations of HgCl₂ impairs sperm quality and promotes hormonal imbalance. The raised oxidative stress seems to be a potential mechanism involved on male reproductive toxicity by mercury.     

Correlated Responses in Male Reproductive Traits in Mice Selected for Litter Size and Body Weight

Correlated responses in male reproductive traits were determined at 4, 6 and 8 weeks of age in lines of mice selected for large litter size (L⁺), large 6-week body weight (W⁺), large litter size and small body weight (L⁺W^-) and small litter size and large body weight (L^-W⁺), and in an unselected control (K). Concentration of serum testosterone and weights of testes, seminal vesicles, epididymides and adrenal glands increased with age. Line differences in testosterone concentration were not detected. L⁺ and W⁺ males exhibited positive correlated responses in testes, epididymides and seminal vescile weights. Testis weight adjusted for body weight was significantly larger for L⁺ than controls and approached significance for W⁺. Realized genetic correlation betestis weight and litter size was 0.60 ± 0.04, and the realized partial genetic correlation holding body weight constant was 0.42. Therefore, pleiotropic loci, acting via the hypothalamic-pituitary axis, affect testis weight and litter size independently of body weight. Additionally, genes influencing overall growth have a pleiotropic effect on testis weight and litter size in mice; the realized genetic correlations of body weight with testis weight and with litter size were 0.60 ± 0.03 and 0.52 ± 0.10. Testis weight increased in both L⁺W^- and L^-W⁺ males. The positive correlated response in L⁺W^- may have resulted from changes in frequency of genes controlling reproductive processes; whereas, in L^-W⁺ it could have been the result of changes in the frequency of genes associated with body weight.     

Behavioural Interactions Selecting for Symmetry and Asymmetry in Sexual Reproductive Systems of Eusocial Species

Understanding the life-history complex of eusociality has remained an enduring problem in evolutionary ecology, partially because natural selection models have considered traits in relative isolation. I aim for a more inclusive model that uses ecological interactions to predict the evolutionary existence of sexual reproduction, sexual reproduction asymmetry, and sex ratios in eusocial species. Using a two-level selection process, with within-population selection on the sex ratio of the sexual caste and between-population selection on the worker sex ratio and the degree of sexual reproduction asymmetry, it is found that a male-haploid genome and a worker caste of pure females is the evolutionary optimum of most initial conditions when, like in eusocial hymenoptera, there is no pair bond between the sexual male and female. That a diploid genome and a worker caste with both males and females is the evolutionary optimum of most initial conditions when, like in eusocial termites, there is a pair bond. That sex-linked genomes may evolve in diploid eusocials, and that the model will not generally maintain sexual reproduction by itself. These results hold for ploidy-levels that behave as quantitative or discrete traits, over a relatively wide range of the relative investment in a sexual male versus sexual female, and for partial sexual systems where the genomic portion with diploid inheritance is either fixed or random.     

Comparative Analysis of the Male Reproductive System in Bothriuridae Scorpions: Structures Associated with the Paraxial Organs and the Presence of Sperm Packages (Chelicerata, Scorpiones)

The male reproductive system of seven species of the family Bothriuridae are compared. These scorpions are Bothriurus flavidus Kraepelin, B. cordubensis Acosta, B. bonariensis (C. L. Koch), B. chacoensis Maury & Acosta, Brachistosternus ferrugineus (Thorell), Timogenes dorbignyi (Guérin-Méneville), T. elegans (Mello-Leitão) and Urophonius brachycentrus Pocock (Bothriuridae). Additional comparisons are made with the buthid Zabius fuscus (Thorell). Observations on the structures associated with the paraxial organs (testis, seminal vesicle and accessory glands) are given. Sperm obtained from the male reproductive tract and fresh spermatophores as well as from the female's genital atrium and seminal receptacles are examined. Accessory glands occur in six out of eight studied bothriurids and in the buthid Z. fuscus. In most species the distal portion of vas deferens has a developed ampulla. All structures vary in size and shape depending on species. Sperm packages were observed in all bothriurids. In contrast, there is no packaged spermatozoa in Z. fuscus. Each sperm package consists of many spermatozoa surrounded by a common membrane that breaks after the spermatophore capsule is everted into the female genital atrium, releasing the spermatozoa. One hour after insemination, the spermatozoa are found in the atrium and in the seminal receptacles of B. flavidus females, but after 24h spermatozoa are found only in the seminal receptacles. The functional significance of the accessory glands and the presence-absence of sperm packages are discussed.     

美国俄亥俄州南部两种不同间伐强度对森林可燃物载量和碳的影响(英文)

本研究的目的是测定两种不同间伐强度下(70%和50%),美国俄亥俄州南部橡树混交林森林可燃物(包括枯落物、木本、草本和倒木)碳储量和其燃烧后可能释放的碳量。研究结果表明枯落物和木本碳含量显著高于草本部分。在50%、70%间伐和对照中,森林枯落物分别占了总的橡树混交林可燃物碳储量的36.6%,50.9%和66.0%。粗木质残体分别占了58.4%,48.0%和32.6%。小的木本和草本在总的森林可燃物中占据很小比例。在50%、70%间伐和对照三种情况下,总的森林可燃物分别是54.07t/ha、41.98t/ha和20.73t/ha。如果对这些森林可燃物进行燃烧,50%、70%间伐和对照中,其森林可燃物将释放碳量分别为90.39t/ha、70.19t/ha和34.66t/ha。虽然它们之间没有产生显著的差异,但和对照进行比较,间伐后仍产生了较多的一、二级森林可燃物。在50%、70%间伐和对照中,分别产生了25.08t/ha、23.47t/ha和14.38t/ha一、二级的可燃物。计划用火在燃烧这些可燃物成分时,在50%、70%间伐和对照中,可能会分别释放41.93t/ha、39.24t/ha和23.55t/ha碳。此研究对使用计划用火来减少引起森林火灾的森林可燃物具有一定的意义。     

Ascorbate Efflux as a New Strategy for Iron Reduction and Transport in Plants

Iron (Fe) is essential for virtually all living organisms. The identification of the chemical forms of iron (the speciation) circulating in and between cells is crucial to further understand the mechanisms of iron delivery to its final targets. Here we analyzed how iron is transported to the seeds by the chemical identification of iron complexes that are delivered to embryos, followed by the biochemical characterization of the transport of these complexes by the embryo, using the pea (Pisum sativum) as a model species. We have found that iron circulates as ferric complexes with citrate and malate (Fe(III)₃Cit₂Mal₂, Fe(III)₃Cit₃Mal₁, Fe(III)Cit₂). Because dicotyledonous plants only transport ferrous iron, we checked whether embryos were capable of reducing iron of these complexes. Indeed, embryos did express a constitutively high ferric reduction activity. Surprisingly, iron(III) reduction is not catalyzed by the expected membrane-bound ferric reductase. Instead, embryos efflux high amounts of ascorbate that chemically reduce iron(III) from citrate-malate complexes. In vitro transport experiments on isolated embryos using radiolabeled ⁵⁵Fe demonstrated that this ascorbate-mediated reduction is an obligatory step for the uptake of iron(II). Moreover, the ascorbate efflux activity was also measured in Arabidopsis embryos, suggesting that this new iron transport system may be generic to dicotyledonous plants. Finally, in embryos of the ascorbate-deficient mutants vtc2-4, vtc5-1, and vtc5-2, the reducing activity and the iron concentration were reduced significantly. Taken together, our results identified a new iron transport mechanism in plants that could play a major role to control iron loading in seeds.     

Application of Chitosan Microparticles for Reduction of Vibrio Species in Seawater and Live Oysters (Crassostrea virginica)

Human Vibrio infections associated with consumption of raw shellfish greatly impact the seafood industry. Vibrio cholerae-related disease is occasionally attributed to seafood, but V. vulnificus and V. parahaemolyticus are the primary targets of postharvest processing (PHP) efforts in the United States, as they pose the greatest threat to the industry. Most successful PHP treatments for Vibrio reduction also kill the molluscs and are not suitable for the lucrative half-shell market, while nonlethal practices are generally less effective. Therefore, novel intervention strategies for Vibrio reduction are needed for live oyster products. Chitosan is a bioactive derivative of chitin that is generally recognized as safe as a food additive by the FDA, and chitosan microparticles (CMs) were investigated in the present study as a potential PHP treatment for live oyster applications. Treatment of broth cultures with 0.5% (wt/vol) CMs resulted in growth cessation of V. cholerae, V. vulnificus, and V. parahaemolyticus, reducing culturable levels to nondetectable amounts after 3 h in three independent experiments. Furthermore, a similar treatment in artificial seawater at 4, 25, and 37°C reduced V. vulnificus levels by ca. 7 log CFU/ml after 24 h of exposure, but 48 h of exposure and elevated temperature were required to achieve similar results for V. parahaemolyticus and V. cholerae. Live oysters that either were artificially inoculated or contained natural populations of V. vulnificus and V. parahaemolyticus showed significant and consistent reductions following CM treatment (5%) compared to the amounts in the untreated controls. Thus, the results strongly support the promising potential for the application of CMs as a PHP treatment to reduce Vibrio spp. in intact live oysters.     

Ginkgo biloba Extract Individually Inhibits JNK Activation and Induces c-Jun Degradation in Human Chondrocytes: Potential Therapeutics for Osteoarthritis

Osteoarthritis (OA) is a common joint disorder with varying degrees of inflammation. The ideal anti-OA drug should have immunomodulatory effects while at the same time having limited or no toxicity. We examined the anti-inflammatory effects of Ginkgo biloba extract (EGb) in interleukin-1 (IL-1)-stimulated human chondrocytes. Chondrocytes were prepared from cartilage specimens taken from patients with osteoarthritis who had received total hip or total knee replacement. The concentrations of chemokines and the degree of cell migration were determined by ELISA and chemotaxis assays, respectively. The activation of inducible nitric oxide synthase (iNOS), mitogen-activated protein kinases (MAPKs), activator protein-1 (AP-1), and nuclear factor-kappaB (NF-κB) was determined by immunoblotting, immunohistochemistry, and electrophoretic mobility shift assay. We found that EGb inhibited IL-1-induced production of chemokines, which in turn resulted in attenuation of THP-1 cell migration toward EGb-treated cell culture medium. EGb also suppressed IL-1-stimulated iNOS expression and release of nitric oxide (NO). The EGb-mediated suppression of the iNOS-NO pathway correlated with the attenuation of activator protein-1 (AP-1) but not nuclear factor-kappaB (NF-κB) DNA-binding activity. Of the mitogen-activated protein kinases (MAPKs), EGb inhibited only c-Jun N-terminal kinase (JNK). Unexpectedly, EGb selectively caused degradation of c-Jun protein. Further investigation revealed that EGb-mediated c-Jun degradation was preceded by ubiquitination of c-Jun and could be prevented by the proteosome inhibitor MG-132. The results imply that EGb protects against chondrocyte degeneration by inhibiting JNK activation and inducing ubiquitination-dependent c-Jun degradation. Although additional research is needed, our results suggest that EGb is a potential therapeutic agent for the treatment of OA.     

No Correlation Between Three Selected Trade‐Offs in Birdsong Performance and Male Quality for a Species With Song Repertoires

Demanding performance of vocal signals, such as birdsong, may be evaluated by trade‐offs among acoustic traits. If individuals differ in their ability to sustain physiologically demanding singing, then aspects of song performance resulting from such trade‐offs could signal individual quality. Song performance can also differ among song types, and it is not known whether this influences the assessment of individual quality. We asked whether three trade‐off‐based measures of song performance indicate male age or aspects of condition (body condition, hematocrit and ectoparasite load) in the dark‐eyed junco (Junco hyemalis), a species with small repertoires. Across a sample of over 100 males, no measure of song performance was related to male age or condition, nor did song performance improve with age for those males recorded in consecutive years. In all cases, the variation in song performance explained by these predictors was small (<4%). Instead, the more song types we recorded from a male, the more likely we were to record high‐performance songs, and this sampling effect was stronger than putative correlations with male quality. These results complement a previous study on this population showing that most variation in performance is found among song types rather than among males. Collectively, the lack of association between trade‐off‐based aspects of song performance and male age or condition, plus variation among song types that interferes with rapid assessment of a male's best performance, indicate that these aspects of song performance do not allow a good assessment of male quality in juncos, and perhaps more generally in species with song repertoires.     

Species loss and gain in communities under future climate change: consequences for functional diversity

It is anticipated that anthropogenic climate change will lead to substantial reassembly within communities in coming decades as individual species shift their ranges to track optimal conditions for growth and survival. As species are lost and gained in communities, what are the consequences for functional trait diversity? Functional traits are the characteristics of species that affect individual performance and provide the vital link between biodiversity at the species level and ecosystem function. We investigated how projected changes in species richness in plant communities under climate change scenarios for the decade 2050 will affect the distribution and diversity of five functional traits. We aggregated range change projections made in Maxent for the decade 2050 across all species in the regional pool of littoral rainforest vines in eastern Australia (n = 163 species). The effect of richness changes on trait diversity was assessed in nine rainforest reserves along the east coast of Australia. Although richness was predicted to significantly decline across all communities, functional diversity remained stable, indicating a decoupling in response to climate change at these two different levels of biological organization. A high degree of redundancy in trait composition in communities may buffer against the loss of function in these plant communities. Scaling‐up our understanding of the impact of climate change from the species level to communities is a critical step towards developing conservation strategies aimed at preserving ecosystem function.     

Heat Shock Induces Rapid Dephosphorylation of τ in Both Female and Male Rats Followed by Hyperphosphorylation Only in Female Rats: Implications for Alzheimer's Disease

Abstract: Female and male 2–3-month-old Sprague-Dawley rats were heat shocked at 42°C for 15 min. At 0, 3, 6, 12, and 24 h after heat shock, qualitative and quantitative immunoblot analysis of cerebral extracts and immunohistochemistry were performed using monoclonal anti-τ antibodies that recognize nonphosphorylated (Tau-1), phosphorylated (PHF-1), and phosphate-independent (Tau-5 and Tau-46) epitopes. At 0 h after heat shock, there was dephosphorylation of τ in both female and male rats as evidenced by (1) accentuation and attenuation of τ isoforms recognized by Tau-1 and PHF-1, respectively, and recognition of additional τ polypeptides by Tau-1, Tau-5, and Tau-46 but not PHF-1; (2) significant increase in the nonphosphorylated Tau-1 epitope with resultant decrease in the ratio of total (phosphorylated plus nonphosphorylated) τ to nonphosphorylated τ; and (3) dephosphorylation of the Tau-1 epitope in the somatodendritic compartment. By 6 h after heat shock, there was progressive hyperphosphorylation of τ in female but not male rats exemplified by (1) upward gel mobility shift recognized by PHF-1, Tau-5, and Tau-46, and by Tau-1 after dephosphorylation; (2) significant increase in the ratio of total τ to nonphosphorylated τ; and (3) rephosphorylation of the Tau-1 epitope in the somatodendritic compartment. Two-dimensional electrophoresis showed shifts to basic and acidic τ polypeptides at 0 and 6 h after heat shock, respectively. Hyperphosphorylation of τ also occurred after multiple heat-shock episodes. Microtubules were present at 6 h after heat shock. There were no differences between control and heat-shocked rats in extracts from peripheral nerves. Thus, we now have a simple rat model to study within 6 h the processes of dephosphorylation and hyperphosphorylation of τ, which are altered in Alzheimer's disease.     

Male and Female Reproductive Success in <Emphasis Type="Italic">Macaca sylvanus</Emphasis> in Gibraltar: No Evidence for Rank Dependence

The relationship between social rank and reproductive success is one of the key questions for understanding differences in primate social group structures. We determined the paternity of 18 infants in a social group of Barbary macaques (Macaca sylvanus) born over a period of 6 yr in the provisioned, free-ranging colony in Gibraltar. We successfully used 13 pairs of primers of variable microsatellite loci to amplify DNA from blood and hair samples and applied the computer programs CERVUS 2.0 and KINSHIP 1.3 to assign paternity to 13 candidate males. We collected data for 19 females that had given birth to 66 infants over a period of 7 yr. We used paternity analyses and female birth records to test the hypothesis that social rank is correlated with reproductive success. Results showed that numbers of paternities and maternities were equally distributed among all reproducing individuals in the social group regardless of rank. Subadult males reproduced as often as adult males. High-ranking females did not start to reproduce earlier than low-ranking females. Interestingly, there was a tendency toward a positive correlation between the ranks of mothers and the ranks of the corresponding fathers. It might be concluded either that a correlation between social rank and reproductive success is generally absent in Barbary macaques or that artificially favorable environmental conditions in Gibraltar preclude any correlation between social rank and reproductive success.     

Nitric Oxide Is Required for Homeostasis of Oxygen and Reactive Oxygen Species in Barley Roots under Aerobic Conditions

Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation of mitochondrial metabolism under most conditions, root tissues often suffer oxygen deprivation during normal development due to the lack of an endogenous supply and isolation from atmospheric oxygen.     

Establishment in Australia of Trichosirocalus horridus a Biological Control Agent for Carduus nutans , and Preliminary Assessment of its Impact on Plant Growth and Reproductive Potential

Testing of the crown weevil , Trichosirocalus horridus, against a range of Australian Aster aceae species confirmed its specificity to nodding thistle , Carduus nutans, and permission was granted for its release in Australia . It has established at the release site , and has been redistributed to other areas in eastern Australia . A field experiment designed to study the impact of this weevil on rosette growth and reproductive potential of the thistle is described . Results indicate that the weevil can kill some plants , and reduce rosette growth of survivors by 50% . The reproductive potential of the attacked plants , measured as seeds per plant , was reduced by 67% . The interaction of this biological control agent with two others already established in Australia , the receptacle weevil , Rhinocyllus conicus, and the seed fly , Urophora solstitialis, is discussed .