Rapid Phytochrome-mediated Changes in Adenosine 5'-Triphosphate Content of Etiolated Bean Buds

This study was designed to determine the effects of red and far red irradiation on ATP metabolism in etiolated bean buds (Phaseolus vulgaris L. var. Red Kidney). Compared to dark controls, red irradiated buds show an initial decline in ATP content at 15 seconds following a 5-minute irradiation. ATP content then rapidly rises to a peak at 1 minute, and then slowly returns to the baseline. The 1-minute promotion of ATP content is red/far red reversible. Acetylcholine does not appear to mimic red light in this system; it causes a marked decrease in ATP content.     

The direct p53 target gene, FLJ11259/DRAM, is a member of a novel family of transmembrane proteins

The tumor suppressor p53 regulates diverse biological processes primarily via activation of downstream target genes. Even though many p53 target genes have been described, the precise mechanisms of p53 biological actions are uncertain. In previous work we identified by microarray analysis a candidate p53 target gene, FLJ11259/DRAM. In this report we have identified three uncharacterized human proteins with sequence homology to FLJ11259, suggesting that FLJ11259 is a member of a novel family of proteins with six transmembrane domains. Several lines of investigation confirm FLJ11259 is a direct p53 target gene. p53 siRNA prevented cisplatin-mediated up-regulation of FLJ11259 in NT2/D1 cells. Likewise in HCT116 p53+/+ cells and MCF10A cells, FLJ11259 is induced by cisplatin treatment but to a much lesser extent in isogenic p53-suppressed cells. A functional p53 response element was identified 22.3 kb upstream of the first coding exon of FLJ11259 and is shown to be active in reporter assays. In addition, chromatin immunoprecipitation assays indicate that p53 binds directly to this element in vivo and that binding is enhanced following cisplatin treatment. Confocal microscopy showed that an FLJ-GFP fusion protein localizes mainly in a punctate pattern in the cytoplasm. Overexpression studies in Cos-7, Saos2, and NT2/D1 cells suggest that FLJ11259 is associated with increased clonal survival. In summary, we have identified FLJ11259/DRAM as a p53-inducible member of a novel family of transmembrane proteins. FLJ11259/DRAM may be an important modulator of p53 responses in diverse tumor types.     

An alternative method for assessing early mortality in contemporary populations

Biological anthropologists are interested in a population's early mortality rates for a variety of reasons. Early mortality (infant or juvenile) is of obvious importance to those interested in demography, but early mortality statistics are useful for life history analysis, paleodemography, and human adaptability studies, among others. In general, the form of mortality statistics is derived from demography, where chronological age is the gold standard for statistical calculation and comparison. However, there are numerous problems associated with the collection, analysis, and interpretation of early mortality statistics based on age, particularly for anthropological research, which is often conducted in small or non-calendrical-age numerate populations. The infant mortality rate (IMR), for example, is notoriously difficult to determine in populations where accurate accounting of age is not routine, and yet it is widely used in demography, public health, medicine, and social science research. Here we offer an alternative to age-based early mortality statistics that makes use of human biologists' interest in, and skill at, assessing human growth and development. Our proposal is to use developmental stages of juveniles instead of relying exclusively on age as the basis for mortality statistics. Death or survival according to a developmental stage (such as crawling or weaning) may provide more accurate data that are also more closely related to the cause of death. Developmental stages have the added advantage of putting infants and children back at the center of the discussion of early mortality by focusing on their activities in relation to their environment. A case study from the Turkana population of Kenya illustrates the use of developmental stages in describing early mortality. Am J Phys Anthropol 107:315–330, 1998. © 1998 Wiley-Liss, Inc.     

Arg16/Gly beta2-adrenergic receptor polymorphism alters the cardiac output response to isometric exercise.

Normotensive adults homozygous for glycine (Gly) of the Arg16/Gly beta2-adrenergic-receptor polymorphism have 1) greater forearm beta2-receptor mediated vasodilation and 2) a higher heart rate (HR) response to isometric handgrip than arginine (Arg) homozygotes. To test the hypothesis that the higher HR response in Gly16 subjects serves to maintain the pressor response [increased cardiac output (CO)] in the setting of augmented peripheral vasodilation to endogenous catecholamines, we measured continuous HR (ECG), arterial pressure (Finapres), and CO (transthoracic echocardiography) during isometric, 40% submaximal handgrip to fatigue in healthy subjects homozygous for Gly (n = 30; mean age +/- SE: 30 +/- 1.2, 13 women) and Arg (n = 17, age 30 +/- 1.6, 11 women). Resting data were similar between groups. Handgrip produced similar increases in arterial pressure and venous norepinephrine and epinephrine concentrations; however, HR increased more in the Gly group (60.1 +/- 4.3% increase from baseline vs. 45.5 +/- 3.9%, P = 0.03), and this caused CO to be higher (Gly: 7.6 +/- 0.3 l/m vs. Arg: 6.5 +/- 0.3 l/m, P = 0.03), whereas the decrease in systemic vascular resistance in the Gly group did not reach significance (P = 0.09). We conclude that Gly16 homozygotes generate a higher CO to maintain the pressor response to handgrip. The influence of polymorphic variants in the beta2-adrenergic receptor gene on the cardiovascular response to sympathoexcitation may have important implications in the development of hypertension and heart failure.     

Behavioural phenotype affects social interactions in an animal network

Animal social networks can be extremely complex and are characterized by highly non-random interactions between group members. However, very little is known about the underlying factors affecting interaction preferences, and hence network structure. One possibility is that behavioural differences between individuals, such as how bold or shy they are, can affect the frequency and distribution of their interactions within a network. We tested this using individually marked three-spined sticklebacks (Gasterosteus aculeatus), and found that bold individuals had fewer overall interactions than shy fish, but tended to distribute their interactions more evenly across all group members. Shy fish, on the other hand, tended to associate preferentially with a small number of other group members, leading to a highly skewed distribution of interactions. This was mediated by the reduced tendency of shy fish to move to a new location within the tank when they were interacting with another individual; bold fish showed no such tendency and were equally likely to move irrespective of whether they were interacting or not. The results show that animal social network structure can be affected by the behavioural composition of group members and have important implications for understanding the spread of information and disease in social groups.     

Structural Mechanisms of Inactivation in Scabies Mite Serine Protease Paralogues

The scabies mite (Sarcoptes scabiei) is a parasite responsible for major morbidity in disadvantaged communities and immuno-compromised patients worldwide. In addition to the physical discomfort caused by the disease, scabies infestations facilitate infection by Streptococcal species via skin lesions, resulting in a high prevalence of rheumatic fever/heart disease in affected communities. The scabies mite produces 33 proteins that are closely related to those in the dust mite group 3 allergen and belong to the S1-like protease family (chymotrypsin-like). However, all but one of these molecules contain mutations in the conserved active-site catalytic triad that are predicted to render them catalytically inactive. These molecules are thus termed scabies mite inactivated protease paralogues (SMIPPs). The precise function of SMIPPs is unclear; however, it has been suggested that these proteins might function by binding and protecting target substrates from cleavage by host immune proteases, thus preventing the host from mounting an effective immune challenge. In order to begin to understand the structural basis for SMIPP function, we solved the crystal structures of SMIPP-S-I1 and SMIPP-S-D1 at 1.85 Å and 2.0 Å resolution, respectively. Both structures adopt the characteristic serine protease fold, albeit with large structural variations over much of the molecule. In both structures, mutations in the catalytic triad together with occlusion of the S1 subsite by a conserved Tyr200 residue is predicted to block substrate ingress. Accordingly, we show that both proteases lack catalytic function. Attempts to restore function (via site-directed mutagenesis of catalytic residues as well as Tyr200) were unsuccessful. Taken together, these data suggest that SMIPPs have lost the ability to bind substrates in a classical “canonical” fashion, and instead have evolved alternative functions in the lifecycle of the scabies mite.     

Antibiotic treatment leads to the elimination of Wolbachia endosymbionts and sterility in the diplodiploid collembolan Folsomia candida

Background  

Wolbachia is an extremely widespread bacterial endosymbiont of arthropods and nematodes that causes a variety of reproductive peculiarities. Parthenogenesis is one such peculiarity but it has been hypothesised that this phenomenon may be functionally restricted to organisms that employ haplodiploid sex determination. Using two antibiotics, tetracycline and rifampicin, we attempted to eliminate Wolbachia from the diplodiploid host Folsomia candida, a species of springtail which is a widely used study organism.     

Design of a potent, soluble glucokinase activator with excellent in vivo efficacy

The optimisation of a series of glucokinase activators is described, including attempts to uncouple the relationship between potency and plasma protein binding, and to better understand the key pharmacokinetic properties of the series. The use of unbound clearance as an optimisation parameter facilitated the identification of GKA50, a compound which combines excellent potency and pharmacokinetics with good free drug levels and solubility, and exhibits in vivo efficacy at 1mg/kg po in an acute rat OGTT model.     

Hydroxylated analogues of the orally active broad spectrum antifungal, Sch 51048 (1), and the discovery of posaconazole [Sch 56592; 2 or (S,S)-5

As part of a detailed study, the syntheses, biological activities, and pharmacokinetic properties of hydroxylated analogues of the previously described broad spectrum antifungal agents, Sch 51048 (1), Sch 50001 (3), and Sch 50002 (4), are described. Based on an overall superior profile, one of the alcohols, Sch 56592 (2), was selected for clinical studies.