Germline mutagenesis mediated by <Emphasis Type="Italic">Sleeping Beauty</Emphasis>transposon system in mice

Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice. Initially, the transposition efficiency was found to be low in cultured systems, but its activity in germ cells was unexpectedly high. This difference in transposition efficiency was found to be largely dependent on chromosomal status of the host genomic DNA and transposon vector design. The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice. Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.     

Vasculitis: mechanisms involved and clinical manifestations

Systemic vasculitis, an inflammatory necrotizing disease of the blood vessel walls, can occur secondary to autoimmune diseases, including connective tissue diseases. Various pathogenic mechanisms have been implicated in the induction of vasculitis, including cell-mediated inflammation, immune complex-mediated inflammation and autoantibody-mediated inflammation. This inflammatory activity is believed to contribute to accelerated atherosclerosis, and also leads to increased risk for cardiovascular events in patients with rheumatoid arthritis and systemic lupus erythematosus. Endothelial cell activation is a common pathogenic pathway in the systemic vasculitis associated with rheumatoid arthritis and systemic lupus erythematosus, with elevated levels of endothelin-1 potentially inducing vascular dysregulation.     

Cloning,characterization, and mutational analysis of a highly active and stable <Emphasis Type="SmallCaps">l</Emphasis>-arabinitol 4-dehydrogenase from <Emphasis Type="Italic">Neurospora crassa</Emphasis>

An NAD⁺-dependent l-arabinitol 4-dehydrogenase (LAD, EC 1.1.1.12) from Neurospora crassa was cloned and expressed in Escherichia coli and purified to homogeneity. The enzyme was a homotetramer and contained two Zn²⁺ ions per subunit, displaying similar characteristics to medium-chain sorbitol dehydrogenases (SDHs). High enzymatic activity was observed for substrates l-arabinitol, adonitol, and xylitol and no activity for d-mannitol, d-arabinitol, or d-sorbitol. The enzyme showed strong preference for NAD⁺ but also displayed a very low yet detectable activity with NADP⁺. Mutational analysis of residue F59, the single different substrate-binding residue between LADs and d-SDHs, failed to confer the enzyme the ability to accept d-sorbitol as a substrate, suggesting that the amino acids flanking the active site cleft may be responsible for the different activity and affinity patterns between LADs and SDHs. This enzyme should be useful for in vivo and in vitro production of xylitol and ethanol from l-arabinose. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Mate preference for multiple cues: interplay between male and nest size in the sand goby, Pomatoschistus minutus

Female mating preferences are often based on more than one cue.In empirical studies, however, different mate choice cues aretypically treated separately ignoring their possible interactions.In the current work, we studied how male body size and sizeof the male's nest jointly affect mate preferences of femalesand gobies, Pomatoschistus minutus. The females were givena binary choice between males that differed either in body sizeor size of their nest or both. We found that neither body sizenor size of the nest alone affected male attractiveness, buttogether these 2 cues had a significant effect. Specifically,large males were more popular among females when they had alarge nest than when they occupied a small nest. The resultssuggest that if interaction effects between multiple mate choicecues are not considered, there is a danger of ignoring or underestimatingthe importance of these cues in sexual selection by female choice.     

Rapid increase of vacuolar volume in response to salt stress

Suspension-cultured cells of mangrove [Bruguiera sexangula (Lour.) Poir.] showed a rapid increase in vacuolar volume under salt stress, although there was no change in the cell volume. The rapid increase in the vacuolar volume was an active process, which followed the activation of the tonoplast H(+)-ATPase and the vacuolar acid phosphatase. The same phenomenon was observed in barley (Hordeum vulgare L. cv. Doriru) root meristematic cells under salt stress but not in pea ( Pisum sativum L.). Increases in vacuolar volume could potentially protect the cytoplasm by decreasing the cytoplasmic volume during the initial phases of salt stress.     

Condition and coalition formation by brood-rearing common eider females

Partner choice is important in nature, and partnerships or coalitionswithin which reproduction is shared are the subject of growinginterest. However, little attention has been given to questionsof which individuals are suitable partners and why. Common eider(Somateria mollissima) females sometimes pool their broods andshare brood-rearing duties, and body condition affects caredecisions. We constructed a model in which females, based ontheir body condition and the structure of the joint brood, assessthe fitness consequences of joining a coalition versus tendingfor young alone. We tested the model's predictions by comparingdata on the condition of females in enduring and transient coalitions.Our model showed that the range of acceptable brood arrays ina female coalition decreases with increasing condition of thefemale, so females tending alone should be in better conditionthan multifemale tenders. This prediction is in agreement withprevious data. The model also predicts that females in goodcondition should join coalitions with females in poor conditionand not with other females in good condition. This predictionwas also supported by data: in enduring two-female coalitions,the positive correlation between the better female's conditionand the difference in condition between the two females wasstronger than would be expected by random grouping of females.In contrast, in transient coalitions of females, this correlationdid not differ from the correlation expected under random grouping.Model assumptions seem to fit with eider natural history, andthe model may prove to be a useful way to study brood amalgamationbehavior of waterfowl in general.     

Genome-wide linkage analysis of longitudinal phenotypes using σ<Superscript>2</Superscript><Subscript>A</Subscript> random effects (SSARs) fitted by Gibbs sampling

The study of change in intermediate phenotypes over time is important in genetics. In this paper we explore a new approach to phenotype definition in the genetic analysis of longitudinal phenotypes. We utilized data from the longitudinal Framingham Heart Study Family Cohort to investigate the familial aggregation and evidence for linkage to change in systolic blood pressure (SBP) over time. We used Gibbs sampling to derive sigma-squared-A-random-effects (SSARs) for the longitudinal phenotype, and then used these as a new phenotype in subsequent genome-wide linkage analyses. Additive genetic effects (sigma2A.time) were estimated to account for approximately 9.2% of the variance in the rate of change of SBP with age, while additive genetic effects (sigma2A) were estimated to account for approximately 43.9% of the variance in SBP at the mean age. The linkage results suggested that one or more major loci regulating change in SBP over time may localize to chromosomes 2, 3, 4, 6, 10, 11, 17, and 19. The results also suggested that one or more major loci regulating level of SBP may localize to chromosomes 3, 8, and 14. Our results support a genetic component to both SBP and change in SBP with age, and are consistent with a complex, multifactorial susceptibility to the development of hypertension. The use of SSARs derived from quantitative traits as input to a conventional linkage analysis appears to be valuable in the linkage analysis of genetically complex traits. We have now demonstrated in this paper the use of SSARs in the context of longitudinal family data.