Isolation and characterization of 149 novel microsatellite DNA markers for striped bass,Morone saxatilis,and cross‐species amplification in white bass,Morone chrysops,and their hybrid

To support detailed genetic analysis of striped bass (Morone saxatilis) and white bass (Morone chrysops), we isolated 153 microsatellite loci from repeat‐enriched striped bass DNA libraries. Of these, 147 markers amplified in striped bass (average 4.7 alleles per locus) and 133 in white bass (average 2.2 alleles per locus). One hundred twenty‐two markers amplified in their hybrid. Development of new microsatellite markers will facilitate evaluations of genetic structure in wild populations and will support pedigree analysis and linkage mapping for selective breeding.     

Predicting development, metabolism and secondary production for the invertebrate predator Bythotrephes

1. Rates of embryonic and post-embryonic development for Bythotrephes cederstroemi from Lakes Erie, Huron and Michigan are represented almost equally well by three empirical models across water temperatures ranging from about 12–22 °C, but at lower temperatures two of the competing models fail and an exponential development rate model proves most robust.
2. Clutch masses of parthenogenic females can greatly exceed the tissue mass of the mother. Clutch size is strongly correlated with the mass of reproductive adults, accounting for over 90% of the variation among individuals. Hence, the mass gain from neonate to reproductive adult can be estimated directly from clutch size.
3. Tissue stoichiometries, respiration quotients and stoichiometries of C and N metabolism were determined experimentally, extending the predictions of existing respiration and growth models.
4. A predictive model for growth and production by the invertebrate predator has advantages over previous model formulations owing to our expanded calibration data base. The model is presented in a modular design that is easily upgraded as additional calibration data become available.     

The role of cytosolic glutamine synthetase in wheat

The role of glutamine synthetase (GS; EC 6.3.1.2) was studied in wheat. GS isoforms were separated by HPLC and the two major leaf isoforms (cytosolic GS1 and chloroplastic GS2) were found to change in content and activity throughout plant development. GS2 dominated activity in green, rapidly photosynthesising leaves compared to GS1 which was a minor component. GS2 remained the main isoform in flag leaves at the early stages of grain filling but GS1 activity increased as the leaves aged. During senescence, there was a decrease in total GS activity which resulted largely from the loss of GS2 and thus GS 1 became a greater contributor to total GS activity. The changes in the activities of the GS isoforms were mirrored by the changes in GS proteins measured by western blotting. The changes in GS during plant development reflect major transitions in metabolism from a photosynthetic leaf (high GS2 activity) towards a senescencing leaf (relatively high GS1 activity). It is likely that, during leaf maturation and subsequently senescence, GS1 is central for the efficient reassimilation of ammonium released from catabolic reactions when photosynthesis has declined and remobilisation of nitrogen is occurring. Preliminary analysis of transgenic wheat lines with increased GS1 activity in leaves showed that they develop an enhanced capacity to accumulate nitrogen in the plant, mainly in the grain, and this is accompanied by increases in root and grain dry matter. The possibility that the manipulation of GS may provide a means of enhancing nitrogen use in wheat is discussed.     

Synthesis of a Vacuolar Acid Invertase in Washed Discs of Storage Root Tissue 11Beta vulgaris L)

The synthesis of acid invertase during washing of red beet storageroots has been investigated using protein synthesis inhibitors,antibiotics, and antibodies raised against the purified invertase.Acid invertase increased during the first 3 d of washing thendecreased, with the rates of both processes dependent on temperature.Concomitantly, acid phosphatase declined throughout this period.Activity gels confirmed the increase in the level of activeinvertase protein. The increase in activity was prevented bycycloheximide, monensin, tunicamycin, and carbonyl cyanide m-chlorophenylhydrazone.Leakage of betanin was measured and ultrastructural observationsundertaken to ensure these compounds had no non-specific effects.Immunoblotting confirmed the synthesis of a new 65 kDa invertaseduring washing and its subsequent loss. The location of theinvertase was investigated by immunoblotting of proteins invacuoles isolated from fresh and washed storage root discs,and indicated that the invertase is localized in the vacuole.The results are discussed in relation to the synthesis and targetingof invertase during the changes induced by washing. Key words: Acid invertase, Beta vulgaris L., protein synthesis, protein targeting, vacuole     

Cuticular hydrocarbons influence female attractiveness to males in the Australian field cricket,Teleogryllus oceanicus

Sexual dimorphism is thought to result from directional sexual selection acting on male signal traits, with female signal traits given little, if any, attention. Here, we examine male mating preferences in the Australian field cricket, Teleogryllus oceanicus. Using a multivariate selection analysis approach, we found that male preferences have the potential to exert selection on female cuticular hydrocarbons, chemical compounds widely used as sexual signals in insects. In addition to finding both stabilizing and disruptive preference gradients, we also found weak negative directional preference for female cuticular hydrocarbons. We contrast our results with a recent study examining sexual selection via female choice on male T. oceanicus cuticular hydrocarbons and suggest that differences in the form and intensity of sexual selection between the genders may provide part of the net selection differential necessary for the evolution of sexual dimorphism in this species.