Anhydride modified cantharidin analogues: synthesis, inhibition of protein phosphatases 1 and 2A and anticancer activity

Two series of anhydride modified cantharidin analogues were synthesised and screened for their phosphatase inhibition (PP1 and PP2A) and cytotoxicity in various cancer cell lines (Ovarian A2780, ADDP; Osteosarcoma 143B; and Colon HCT116 and HT29). One series was synthesised by a novel, high yielding one-pot hydrogenation-ring-opening-esterification procedure, the other by acid catalysed acetal formation. Analogues 5-7 and 9 displayed moderate PP2A selectivity (ca. 5- to 20-fold) and inhibition typically in the low microM range (comparable, in some cases to cantharidin). The anticancer activity of these analogues varied with the cell line under study; however, many of them showed selective cytotoxicity for the colon tumour cell lines.     

Karyotypic analysis of adult pluripotent stem cells

Three categories of precursor cells have been identified in postnatal mammals: tissue-committed progenitor cells, germ layer lineage-committed stem cells and lineage-uncommitted pluripotent stem cells. Progenitor cells are the immediate precursors of differentiated tissues. Germ layer lineage stem cells can be induced to form multiple cell types belonging to their respective ectodermal, mesodermal, and endodermal embryological lineages. Pluripotent stem cells will form somatic cell types from all three primary germ layer lineages. Progenitor cells demonstrate a finite life span before replicative senescence and cell death occur. Both germ layer lineage stem cells and pluripotent stem cells are telomerase positive and display extensive capabilities for self-renewal. Stem cells which undergo such extensive replication have the potential for undergoing mutations that may subsequently alter cellular functions. Gross mutations in the genome may be visualized as chromosomal aneuploidy and/or chromosomes that appear aberrant. This study was designed to determine whether any gross genomic mutations occurred within the adult pluripotent stem cells. Karyotypic analysis was performed using pluripotent stem cells purified from adult male rats using established procedures. Giemsa Banding was used in conjunction with light microscopy to visualize metaphase chromosome spreads. To date over 800 metaphase spreads have been analyzed. We found that the metaphase spreads averaged 42 chromosomes and concluded that these pluripotent stem cells isolated from adult rats have a normal karyotype.     

Modification of the anticonvulsant efficacy of diazepam by Ro-15-1788 in the kindled amygdaloid seizure model

The effects of various doses of diazepam and the new central benzodiazepine antagonist Ro-15-1788 were investigated in fully amygdaloid kindled rats. Diazepam had a pronounced dose-dependent anticonvulsant effect in this model. Ro-15-1788 dose-dependently reduced the behavioral ranks of the elicited kindled seizures to a maximum of 60% of control without consistently modifying the afterdischarge duration. No prestimulation convulsant effects were seen with Ro-15-1788. When 2 mg/kg i.p. of Ro-15-1788 was given after various doses of diazepam, the prestimulation sedation and ataxia anticonvulsant effects of diazepam (0.5-2.0 mg/kg) were attenuated by treatment with 2 mg/kg dose of Ro-15-1788. At the low dose of diazepam (0.25 mg/kg), increased reduction of behavioral rank and after discharge duration was seen after the 2 mg/kg dose of Ro-15-1788. Thus, Ro-15-1788 appears not to have proconvulsant properties in the kindled amygdaloid seizure model. Further, Ro-15-1788 appears to have some anticonvulsant properties of its own. Mixed agonist and antagonist effects were seen with Ro-15-1788 when given after various doses of diazepam in this model.     

Identification and characterisation of seed storage protein transcripts from Lupinus angustifolius

Background  

In legumes, seed storage proteins are important for the developing seedling and are an important source of protein for humans and animals. Lupinus angustifolius (L.), also known as narrow-leaf lupin (NLL) is a grain legume crop that is gaining recognition as a potential human health food as the grain is high in protein and dietary fibre, gluten-free and low in fat and starch.     

ADH1 expression inversely correlates with CDR1 and CDR2 in Candida albicans from chronic oral candidosis in APECED (APS-I) patients

Expression of the alcohol dehydrogenase gene ADH1, which converts ethanol into carcinogenic acetaldehyde, significantly inversely correlated with the expression of CDR1 and CDR2, genes linked to azole resistance in Candida albicans isolated from chronic oral candidosis in autoimmune polyendocrinopathy-candidosis-ectodermal dystrophy (APECED, APS-I) patients. This is a novel link between candidal two-carbon metabolism genes and azole resistance.     

Metrics of predation: perils of predator-prey ratios

We developed an original modeling approach using program Stella® to investigate the usefulness of predator–prey ratios (PPRs) for interpreting top-down and bottom-up forcing on moose Alces alces. We included density-dependent feedbacks for the moose population, allowed K to vary based on amount and quality of available forage for moose, integrated effects of compensatory mortality, and added time lags in wolves Canis lupus tracking the moose population. Modeling scenarios we developed included bottom-up and top-down regulation as predetermined outcomes. We then evaluated whether PPRs would reflect the various combinations of trajectories of predator and prey populations under top-down versus bottom-up regulation. The resulting patterns of PPRs were impossible to disentangle from one another, and did not provide reliable insights into whether top-down or bottom-forcing occurred, especially over short time spans where critical decisions related to management of moose and wolves might be necessary. Only under top-down regulation did PPRs reflect the degree of predation experienced by moose, but in that instance, knowledge of top-down regulation must be known a priori to correctly interpret PPRs. Potential problems with interpreting PPRs include their double-variable nature, which resulted in the failure to reflect patterns of increase and decrease for predators and prey. We suggest that confidence intervals for PPRs be calculated from a binomial, similar to that proposed for sex and age ratios, which should help discourage the inappropriate use of this metric. We caution that the temptation to use PPRs often is irresistible, but their reliability is highly questionable. We provide an alternative method to using PPRs or other predation metrics for determining whether top-down or bottom-up forcing is occurring by adopting an approach based on the physical condition and life-history characteristics of prey.     

Condition of mule deer during winter: stress and spatial overlap with North American elk

We assessed body condition, diet quality (indexed by fecal nitrogen), and stress levels (using fecal glucocorticoid metabolites) in mule deer Odocoileus hemionus in southeastern Idaho, USA, during a mild (2007) and a harsh winter (2008) to evaluate spatial overlap and potential competition with North American elk Cervus elaphus. We used data from GPS telemetry to construct spatially explicit maps of local population density of elk for January–April. Loss of body condition over winter in yearling and adult female mule deer was not related to elk density but to winter severity. Fecal nitrogen increased as winter progressed in both winters, was significantly lower during 2008 than in 2007, but was not related to local population density of elk. In the mild winter of 2007, a significant positive relationship existed between local population density of elk and fecal glucocorticoid metabolite levels of mule deer, indicating increased physiological stress among mule deer wintering in close proximity to elk. Fecal glucocorticoid metabolite levels in deer were lower in 2008 than in 2007 and exhibited no significant relationship with elk density. Declining fecal glucocorticoid levels through winter may be typical of northern cervids. No difference existed in levels of fecal glucocorticoids between sexes of deer. A reduction in elk populations may not improve diet quality, physiological stress levels, or body condition of mule deer on winter range, especially during severe winters. Consequently, management and conservation of winter habitat are more likely to benefit mule deer than would altering density of elk.     

Molecules incorporating a benzothiazole core scaffold inhibit the N-myristoyltransferase of Plasmodium falciparum

Recombinant N-myristoyltransferase of Plasmodium falciparum (termed PfNMT) has been used in the development of a SPA (scintillation proximity assay) suitable for automation and high-throughput screening of inhibitors against this enzyme. The ability to use the SPA has been facilitated by development of an expression and purification system which yields considerably improved quantities of soluble active recombinant PfNMT compared with previous studies. Specifically, yields of pure protein have been increased from 12 microg x l(-1) to >400 microg x l(-1) by use of a synthetic gene with codon usage optimized for expression in an Escherichia coli host. Preliminary small-scale 'piggyback' inhibitor studies using the SPA have identified a family of related molecules containing a core benzothiazole scaffold with IC50 values <50 microM, which demonstrate selectivity over human NMT1. Two of these compounds, when tested against cultured parasites in vitro, reduced parasitaemia by >80% at a concentration of 10 microM.     

Chronic stress and its effects on adrenal cortex apoptosis in pregnant rats

The model of chronic intermittent stress by immobilization during pregnancy may produce alterations in the mechanisms that maintain adrenal gland homeostasis. In earlier investigations using this model, significant variations in plasma prolactin and corticosterone levels, and adrenal gland weights were observed. We hypothesized that chronic stress causes changes in apoptosis in the adrenal glands of pregnant rats. We identified and quantified apoptotic cells in the adrenal cortex and examined their ultrastructural characteristics using transmission electron microscopy. Adrenal glands of pregnant rats at gestation days 12, 17 and 21 were studied for control and experimental (stressed) rats. Immunolabelling techniques, stereological analysis and image quantification of adrenal gland sections were combined to determine differences in apoptosis in the different cell populations of the adrenal cortex. The apoptotic index of the experimental rats showed a significant reduction at gestation day 17, while at days 12 and 21 there were no differences from controls. Moreover, the apoptotic index of the reticular zones in control and experimental animals showed a significant increase compared to the glomerular and fascicular zones at the three gestation times studied. Chronic stress by immobilization reduced the caspase-dependent apoptotic index at gestation day 17, which may be related to variations in plasma concentrations of estrogens and prolactin.