Altered telomeres in tumors with ATRX and DAXX mutations

The proteins encoded by ATRX and DAXX participate in chromatin remodeling at telomeres and other genomic sites. Because inactivating mutations of these genes are common in human pancreatic neuroendocrine tumors (PanNETs), we examined the telomere status of these tumors. We found that 61% of PanNETs displayed abnormal telomeres that are characteristic of a telomerase-independent telomere maintenance mechanism termed ALT (alternative lengthening of telomeres). All of the PanNETs exhibiting these abnormal telomeres had ATRX or DAXX mutations or loss of nuclear ATRX or DAXX protein. ATRX mutations also correlate with abnormal telomeres in tumors of the central nervous system. These data suggest that an alternative telomere maintenance function may operate in human tumors with alterations in the ATRX or DAXX genes.     

Queen pheromone blocks aversive learning in young worker bees

Queen mandibular pheromone (QMP) has profound effects on dopamine signaling in the brain of young worker honey bees. As dopamine in insects has been strongly implicated in aversive learning, we examined QMP's impact on associative olfactory learning in bees. We found that QMP blocks aversive learning in young workers, but leaves appetitive learning intact. We postulate that QMP's effects on aversive learning enhance the likelihood that young workers remain in close contact with their queen by preventing them from forming an aversion to their mother's pheromone bouquet. The results provide an interesting twist to a story of success and survival.     

A previously unknown maltose transporter essential for starch degradation in leaves

A previously unknown maltose transporter is essential for the conversion of starch to sucrose in Arabidopsis leaves at night. The transporter was identified by isolating two allelic mutants with high starch levels and very high maltose, an intermediate of starch breakdown. The mutations affect a gene of previously unknown function, MEX1. We show that MEX1is a maltose transporter that is unrelated to other sugar transporters. The severe mex1 phenotype demonstrates that MEX1is the predominant route of carbohydrate export from chloroplasts at night. Homologous genes in plants including rice and potato indicate that maltose export is of widespread significance.     

The Genome sequence of the SARS-associated coronavirus

We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.     

Forecasting lucerne productivity under dryland farming conditions in central-western and western New South Wales

Possibilities for growing dryland lucerne (Medicago sativa L.) productively in drier parts of central-western and western New South Wales (NSW) were investigated by consideration of meteorological records. Annual rainfall data and estimated evapotranspiration data for 1995-1999 were compiled to calculate lucerne growing days and N₂-fixing days at Condobolin, Trangie, Cobar and Wentworth. This information was used in conjunction with seasonal indices of dry matter production and nitrogen fixation derived from the work of Bowman et al. [Aust J Exp Agric 42 (2002) 439] at Trangie to estimate yearly biomass production and N₂ fixation for the four locations. It was concluded that (i) there are good prospects for growing lucerne productively on suitable soils located in that extensive region of central-western and western NSW between the 450 and 300 mm isohyets if it is feasible to develop techniques for establishment and management to maintain stands at an acceptable density—not less than eight plants/m², (ii) there are only poor prospects for growing lucerne in those western parts of the state where annual rainfall averages less 300 mm, and (iii) annual rainfall, irrespective of other factors such as erratic distribution, is a rough guide to potential lucerne production. In addition, there were indications that, were the threshold for cessation of lucerne N₂ fixation reduced by 2 °C (say from 10 to 8 °C), annual N₂ fixation would be enhanced by more than 20%.     

Varietal selection for perennial crops where data relate to multiple harvests from a series of field trials

Varietal selection for yield from a series of multi-environment trials can be regarded as a multi-trait selection problem in which the yields in different environments are synonymous with traits. As such an analysis of the data combined across environments should be conducted in order to form an index for selection. Analytical methods that include appropriate models for both the genetic variance structure (that is, the variances and covariances of genotype effects from different environments) and the residual variance structure (which typically comprises spatial covariance models for each trial) have been published previously. In the case of perennial crops, yields are often obtained from multiple harvests which implies that the data comprise short sequences of repeated measurements. Varietal performance in individual harvests is important for selection so that a combined analysis across both trials and harvests is required. The repeated measures nature of the data provides additional modelling challenges. In this paper we propose an approach for the analysis of multi-environment, multi-harvest data that accommodates the major sources of variation and correlation (including temporal). The approach is illustrated using two examples from sugarcane breeding programmes. The proposed models were found to provide a superior fit to the data and thence more accurate selection decisions than the common practice of conducting separate analyses of individual trials and harvests.     

Effects of clove oil and MS-222 on blood hormone profiles in rainbow trout Oncorhynchus mykiss, Walbaum

Clove oil has been demonstrated to be an effective, inexpensive anaesthetic and euthanizing agent for a number of fish species, including rainbow trout, used in aquaculture and fisheries research. However, the potential for clove oil to cause perturbations in important plasma hormone concentrations has not been investigated. The effect of anaesthesia and euthanasia in trout with eugenol (the active ingredient in clove oil) on plasma cortisol, glucose, growth hormone (GH) and two thyroid hormones [tri‐iodothyronine (T₃) and thyroxine (T₄)] was compared with tricaine methanesulfonate (MS‐222) anaesthesia, and stunning by cranial concussion in two experiments. Effects on blood chemistry were different when comparing the particular anaesthetic method being used. Stunning fish significantly increased plasma cortisol and glucose levels (both P<0.05), while euthanizing fish using either clove oil or MS‐222 had no effect on these hormone levels. In contrast, the levels of GH, T₃ and T₄ hormones were unaffected regardless of whether fish were euthanized by stunning, MS‐222 or clove oil. Variation in effects between hormones were observed using clove oil eugenol. In fish sampled 10 min after anaesthetizing with 150 mg L^?1 of eugenol, cortisol levels were significantly decreased (P<0.03), while there were no differences in either glucose or GH levels. Tri‐iodothyronine and T₄ also showed significantly elevated levels (P<0.05) after 10‐min exposure to eugenol. These results highlight the importance of investigating the potential effects of any new anaesthetic or euthanizing compounds on blood plasma parameters, prior to using them in a research setting, or when comparing results to other studies which have utilized alternative anaesthetic compounds.