The response of cerambycid beetles (Coleoptera: Cerambycidae) to long‐term fire frequency regimes in subtropical eucalypt forest

Fire has a varied influence on plant and animal species through direct (e.g. fire‐induced mortality) and indirect (e.g. modification of habitat) effects. Our understanding of the influence of fire regime on invertebrates and their response to fire‐induced modifications to habitat is poor. We aimed to determine the response of a beetle family (Coleoptera: Cerambycidae) to varying fire treatments and hypothesised that the abundance of cerambycid beetles is influenced by fire frequency due to modifications in habitat associated with the fire treatments. Arthropods were sampled across 3 months in annually and triennially burnt areas (treatments starting in 1952 and 1973 respectively), an area unburnt since 1946, and a former unburnt treatment, burnt by wildfire in 2006. Eleven different cerambycid taxa were collected using flight intercept panel traps, dominated by three species (Ipomoria tillides, Adrium sp. and Bethelium signiferum) which made up 99% of individuals collected. Over the sampling period the long unburnt treatment had significantly lower species richness than the triennial and wildfire treatments. Cerambycid abundance was significantly higher in the triennially burnt treatment than in all other fire treatments. Ipomoria tillides was more abundant in both frequently burnt treatments, Adrium sp. was more common in triennially burnt areas, whereas B. signiferum, was more common in the wildfire affected treatment. Some, but not all, cerambycid beetles were more common in areas with a more open understorey (i.e. resulting from frequent burning), and lower tree basal area, as this likely influences their ability to fly easily between food sources. Cerambycid abundance was positively related to the volume of coarse woody debris and healthy tree crowns. Cerambycid beetles were clearly influenced by historic fire regime, suggesting that changes in fire regime can potentially have a profound influence on arthropod assemblages, and subsequent influences on ecosystem processes, which are currently poorly understood.     

Swine generated by somatic cell nuclear transfer have increased incidence of intrauterine growth restriction (IUGR)

While somatic cell nuclear transfer (SCNT) has been successful in several species, many pregnancies are lost and anomalies are found in fetal and perinatal stages. In this study SCNT and artificial inseminations (AI) populations were compared for litter size, average birth weight, piglets alive at birth, stillborn, mummies, dead at the first week, intrauterine growth restriction (IUGR) and large for gestational age (LGA). Twenty-three SCNT litters (143 individuals) were compared to 112 AI litters (1300 individuals). Litter size average was 11.5 for AI and 6.2 for SCNT. Litter weight and average birth weight adjusted by litter size were significantly (p < 0.05) higher in AI than in SCNT litters. The SCNT population had a significant (p < 0.01) increase in the number of IUGRs per litter with LSmeans 7.2 +/- 1.4 versus 19.4 +/- 3.5 and means 8.0 +/- 10.8 versus 15.5 +/- 24.5 for AI and SCNT, respectively. Additionally, there was a trend for higher postnatal mortality and stillbirths in the SCNT population. These findings demonstrate that there are some differences between SCNT-derived and AI litters. SCNT-derived pigs are excellent models to study epigenetic factors and genes involved in IUGRs, and to develop effective means to improve fetal growth in humans and animals.     

Citrate synthase mutants of Sinorhizobium meliloti are ineffective and have altered cell surface polysaccharides

The gltA gene, encoding Sinorhizobium meliloti 104A14 citrate synthase, was isolated by complementing an Escherichia coli gltA mutant. The S. meliloti gltA gene was mutated by inserting a kanamycin resistance gene and then using homologous recombination to replace the wild-type gltA with the gltA::kan allele. The resulting strain, CSDX1, was a glutamate auxotroph, and enzyme assays confirmed the absence of a requirement for glutamate. CSDX1 did not grow on succinate, malate, aspartate, pyruvate, or glucose. CSDX1 produced an unusual blue fluorescence on medium containing Calcofluor, which is different from the green fluorescence found with 104A14. High concentrations of arabinose (0.4%) or succinate (0. 2%) restored the green fluorescence to CSDX1. High-performance liquid chromatography analyses showed that CSDX1 produced partially succinylated succinoglycan. CSDX1 was able to form nodules on alfalfa, but these nodules were not able to fix nitrogen. The symbiotic defect of a citrate synthase mutant could thus be due to disruption of the infection process or to the lack of energy generated by the tricarboxylic acid cycle.     

Primary structure of the 2-O-methyl-alpha-L-fucose-containing side chain of the pectic polysaccharide,rhamnogalacturonan II

A 2-O-methylfucosyl-containing heptasaccharide was released from red wine rhamnogalacturonan II (RG-II) by acid hydrolysis of the glycosidic linkage of the aceryl acid residue (AceA) and purified to homogeneity by size-exclusion and high-performance anion-exchange chromatographies. The primary structure of the heptasaccharide was determined by glycosyl-residue and glycosyl-linkage composition analyses, ESIMS, and by 1H and 13C NMR spectroscopy. The NMR data indicated that the pyranose ring of the 2,3-linked L-arabinosyl residue is conformationally flexible. The L-Arap residue was confirmed to be alpha-linked by NMR analysis of a tetraglycosyl-glycerol fragment, [alpha-L-Arap-(1-->4)-beta-D-Galp-(1-->2)-alpha-L-AcefA-(1-->3)-beta-L-Rhap-(1-->3)-Gro], generated by Smith degradation of RG-II. Our data together with the results of a previous study,(1) establish that the 2-O-Me Fuc-containing nonasaccharide side chain of wine RG-II has the structure (Api [triple bond] apiose): [see structure]. Data are presented to show that in Arabidopsis RG-II the predominant 2-O-MeFuc-containing side chain is a mono-O-acetylated heptasaccharide that lacks the non-reducing terminal beta-L-Araf and the alpha-L-Rhap residue attached to the O-3 of Arap, both of which are present on the wine nonasaccharide.     

Ralstonia eutropha H16 encodes two and possibly three intracellular Poly[D-(-)-3-hydroxybutyrate] depolymerase genes

Intracellular poly[D-(-)-3-hydroxybutyrate] (PHB) depolymerases degrade PHB granules to oligomers and monomers of 3-hydroxybutyric acid. Recently an intracellular PHB depolymerase gene (phaZ1) from Ralstonia eutropha was identified. We now report identification of candidate PHB depolymerase genes from R. eutropha, namely, phaZ2 and phaZ3, and their characterization in vivo. phaZ1 was used to identify two candidate depolymerase genes in the genome of Ralstonia metallidurans. phaZ1 and these genes were then used to design degenerate primers. These primers and PCR methods on the R. eutropha genome were used to identify two new candidate depolymerase genes in R. eutropha: phaZ2 and phaZ3. Inverse PCR methods were used to obtain the complete sequence of phaZ3, and library screening was used to obtain the complete sequence of phaZ2. PhaZ1, PhaZ2, and PhaZ3 share approximately 30% sequence identity. The function of PhaZ2 and PhaZ3 was examined by generating R. eutropha H16 deletion strains (Delta phaZ1, Delta phaZ2, Delta phaZ3, Delta phaZ1 Delta phaZ2, Delta phaZ1 Delta phaZ3, Delta phaZ2 Delta phaZ3, and Delta phaZ1 Delta phaZ2 Delta phaZ3). These strains were analyzed for PHB production and utilization under two sets of conditions. When cells were grown in rich medium, PhaZ1 was sufficient to account for intracellular PHB degradation. When cells that had accumulated approximately 80% (cell dry weight) PHB were subjected to PHB utilization conditions, PhaZ1 and PhaZ2 were sufficient to account for PHB degradation. PhaZ2 is thus suggested to be an intracellular depolymerase. The role of PhaZ3 remains to be established.     

Specificity determinants in phosphoinositide dephosphorylation: crystal structure of an archetypal inositol polyphosphate 5-phosphatase

Inositol polyphosphate 5-phosphatases are central to intracellular processes ranging from membrane trafficking to Ca(2+) signaling, and defects in this activity result in the human disease Lowe syndrome. The 1.8 resolution structure of the inositol polyphosphate 5-phosphatase domain of SPsynaptojanin bound to Ca(2+) and inositol (1,4)-bisphosphate reveals a fold and an active site His and Asp pair resembling those of several Mg(2+)-dependent nucleases. Additional loops mediate specific inositol polyphosphate contacts. The 4-phosphate of inositol (1,4)-bisphosphate is misoriented by 4.6 compared to the reactive geometry observed in the apurinic/apyrimidinic endonuclease 1, explaining the dephosphorylation site selectivity of the 5-phosphatases. Based on the structure, a series of mutants are described that exhibit altered substrate specificity providing general determinants for substrate recognition.