Protein synthesis by the accessory gland of male house cricket,Acheta domesticus

Morphology and development of the accessory glands in various female cricket species

The study presents new results with regard to the morphometric and ultrastructural development of the accessory glands in females of the three cricket species Gryllus bimaculatus, Gryllus assimilis, and Acheta domesticus. Furthermore, possible age-dependence of secretory productivity of single organs was analyzed by application of the ligature technique introduced in a previous contribution. Within the first 12 days of the adult phase, the accessory glands of all investigated cricket species exhibit a significant increase in length and width which assumes values between 50 and 100%. This gland growth is rather the result of a continuous increase in cellular volume and less that of mitotic cell propagation. In all species height and width of single gland cells increase by 60-80% within the studied time interval. These changes in morphometry are commonly accompanied by ultrastructural modifications. Total glandular secretion is subject to an increase from the 5th to the 12th day of adult age. This development corresponds well with the number of eggs contemporaneously oviposited into the substrate and thus underlines the hypothesis, according to which the main function of the secretion consists in acting as a lubricant for the facilitated transport of the oocytes through the ovipositor.

The evolution of polyandry: patterns of genotypic variation in female mating frequency, male fertilization success and a test of the sexy-sperm hypothesis

The sexy-sperm hypothesis predicts that females obtain indirect benefits for their offspring via polyandy, in the form of increased fertilization success for their sons. I use a quantitative genetic approach to test the sexy-sperm hypothesis using the field cricket Teleogryllus oceanicus. Previous studies of this species have shown considerable phenotypic variation in fertilization success when two or more males compete. There were high broad-sense heritabilities for both paternity and polyandry. Patterns of genotypic variance were consistent with X-linked inheritance and/or maternal effects on these traits. The genetic architecture therefore precludes the evolution of polyandry via a sexy-sperm process. Thus the positive genetic correlation between paternity in sons and polyandry in daughters predicted by the sexy-sperm hypothesis was absent. There was significant heritable variation in the investment by females in ovaries and by males in the accessory gland. Surprisingly there was a very strong genetic correlation between these two traits. The significance of this genetic correlation for the coevolution of male seminal products and polyandry is discussed.

Development of the accessory glands in the genital tract of female Teleogryllus commodus WALKER (Insecta, Orthoptera)

The development of the female accessory glands in Teleogryllus commodus was studied by detailed morphometric and stereological analyses. In addition, a microsurgical method was developed to quantify the gland secretion. The morphometric results yield evidence that the glands are subject to a significant growth during peak differentiation, starting immediately after the adult moult. The gland growth is exclusively caused by a hypertrophy of single gland cells with respective volume gains between 400 and 700%. According to the stereological results, the volume of mitochondria per cell is marked by an up to fourfold increase during peak differentiation. Other cell structures (rER, sER) are characterized by a similar propagation behavior. The nucleus and nucleolus grow simultaneously with the cell, indicating high production of site-specific macromolecules. Infolds of the basal cell membrane cause a progressive enlargement of the basal cell surface ensuring an increased uptake of secretory precursors from the hemolymph. Quantitative studies show that the total production of secretion increases with proceeding age and can be correlated with a rising egg-laying activity, starting on the eighth day of adult's life. This underlines the main function of the secretion as a lubricant for a facilitated transport of the eggs through the ovipositor.

Extracellular localization of cyclic GMP in the house cricket male accessory reproductive gland and its fate in mating

The male accessory reproductive gland (ARG) of the house cricket, Acheta domesticus (L.), contains an exceedingly high concentration of cyclic GMP, about 1,000 pmol/mg protein. Immunofluorescent localization and radioimmunoassay measurements show that cyclic GMP is concentrated in a small number of tubules. It accumulates in the tubule lumina where it is protected from degradation by phosphodiesterases. Cyclic GMP is secreted by the ARG and is incorporated into spermatophores. Over 80% of spermatophore cyclic GMP is found in the handle-capillary tube, a thin conduit through which sperm pass during transfer to the female. The concentration of cyclic GMP in the insemination fluid is about 20 microM but does not appear to be specifically associated with the sperm. Cyclic GMP enters the female spermatheca during insemination but disappears rapidly. Physiological effects of cyclic GMP on sperm were not observed nor was an effect of cyclic GMP observed on egg laying by mated females. Cyclic AMP was localized on sperm flagella in the spermatophore and in the spermatheca. These studies indicate that cyclic nucleotides have important roles in insect reproduction and that the house cricket is a good model for elucidating these functions.

Analysis of the translational capacity of the male accessory gland during aging in Acheta domesticus

The protein synthesizing capacity of the male cricket accessory gland was inspected for changes associated with aging by analysis of organs from young (2 weeks post-imaginal molt), middle-aged (4 and 6 weeks) and senescent (8 weeks) animals. Total RNA content and the percentage of ribosomes in polysomes show an increase up to 4 weeks and then a steady decline. The rates of protein synthesis by young and old glands incubated in vitro were comparable, although the old glands were significantly less efficient in precursor uptake and therefore showed lower incorporation levels. The overall picture appears to be one of a steady but unspectacular decline in protein synthesizing capacity in aging animals. The quality of the secretory proteins formed by young and old glands was inspected by SDS--polyacrylamide gel electrophoresis and by isoelectric focusing, using both wide and narrow pH-range gels. While some differences in the banding patterns of isoelectric focusing gels were detected, they were eliminated by the inclusion of Triton X-100 in the gels. No other evidence for age-associated qualitative or quantitative changes was detected, strongly suggesting that proteins from young and old glands are identical.

Streptomycin: separation of polysomal and non-polysomal messenger ribonucleoproteins

In the presence of 0.02 M streptomycin, all of the polysomes precipitate from male cricket (Acheta domesticus) accessory gland and chick embryonic tissue post-mitochondrial fractions. All non-polysomal messenger-like ribonucleoprotein preparations tested remain in solution.

Cytodifferentiation in the accessory glands of Tenebrio molitor II. Patterns of leucine incorporation in the tubular glands of post-ecdysial adult males

The tubular accessory gland of male mealworm beetles undergoes rapid and progressive terminal differentiation in the 8-day period after ecdysis to the adult. Total protein and RNA content are maximal at five and eight days respectively. Rates of leucine incorporation rise gradually through the first four days and then increase abruptly in the 5-to 7-day interval. SDS-polyacrylamide gel electrophoresis demonstrates a variety of proteins; two classes with high mobility (Class A and B) appear prominent in homogenates of 5- to 8-day glands. Double-label procedures show that as the glands mature, an increasing proportion of the total leucine incorporation passes into Class A and B proteins, until at eight days, Class A and B proteins account for 50% of the total for the gland. The relative incorporation into A vs. B also changes linearly over this interval. The developmental program of the tubular gland includes both a linearly biosynthetic increase in the proportion of differentiation-specific proteins and an abrupt change in the overall rates of leucine incorporation.