Carbohydrate analysis of beech honeydew

Abstract

Honeydew from the beech scale insect, Ultracoelostoma assimile, infesting the beech species Nothofagus fusca and N. solandri var. solandri contained fructose, sucrose, glucose, and several non-reducing oligosaccharides composed of glucose and fructose residues. Although the total carbohydrate content varied from 5 to 64 g/100 g, and was dependent on rainfall in the sampling area, there were no significant differences between the honeydews of N. fusca and N. solandri sampled on the same day in the absence of recent rain. The mean proportional composition (±SD) of such samples were 42±5% fructose, 23±8% sucrose, 1 ± 0.4% glucose, and 33±6% oligosaccharides. A refractometer calibrated against sucrose slightly overestimated total carbohydrate of honeydew and such data should be divided by a correction factor of 1.145. The energy value of honeydew carbohydrate was estimated to be 16J mg^?1 (dry weight). Honeydew contained little protein (<50 mg g^?1).     

Energy dispersive analysis of X-rays study of the distribution of chlorhexidine diacetate and cetylpyridinium chloride on the Pseudomonas aeruginosa bacteriophage F116

Using an energy dispersive analyser of X-rays fitted to a scanning electron microscope, chlorhexidine was shown not to bind onto F116 bacteriophage, unlike cetylpyridinium chloride, which possibly penetrated the phage. This could explain the difference in viricidal activity between the two compounds.     

Identification of a yeast snRNP protein and detection of snRNP-snRNP interactions

The RNA8 gene of Saccharomyces cerevisiae encodes an unusually large (260 kd) protein required for pre-mRNA splicing. Immunological procedures have been used to demonstrate that the RNA8 protein is in stable association with the small nuclear RNAs snR7L and snR7S, which are also known to be required for splicing and which are present in spliceosomal complexes. RNA8 is also involved in an ATP-dependent association with two other small nuclear RNAs, snR14 and snR6. It is proposed that this represents an ATP-dependent interaction between small nuclear ribonucleoprotein particles that precedes their entry into the spliceosome.     

Are nesting seabirds important determinants of invertebrate community composition on subantarctic Adams Island?

Nesting seabirds import marine-derived nutrients into terrestrial food webs, affecting invertebrate abundance and community composition directly, through provision of decaying animal matter as a food source, and indirectly through effects on vegetation and prey abundance. Invertebrates have shown strong responses to seabird presence in some, but not all, ecosystems previously studied. In contrast to mainland range contractions, New Zealand’s subantarctic islands retain abundant seabird populations. We sampled ground invertebrates on mammal-free Adams Island, using pitfall traps. We surveyed sites in two vegetation types (tussock and forest) with either no nesting seabirds or nesting colonies of Gibson’s wandering albatross, sooty shearwaters or white-headed petrels. We collected 11 invertebrate orders and identified 20 Coleoptera species or higher taxa. The carrion beetle, Paracatops antipoda comprised over 50 % of Coleoptera individuals collected. P. antipoda was more abundant in forest than tussock and was positively associated with sooty shearwaters and negatively associated with white-headed petrels when compared with bird-free sites using a Poisson generalized linear model. Sooty shearwaters were also associated with elevated abundance of several herbivorous and invertebrate decomposer taxa. Nesting seabirds do appear to influence invertebrate community composition on Adams Island, but the direction of this effect appears to be taxa-specific. Further sampling with spatial replication of colonies is required to determine the extent to which these apparent taxa-specific responses are consistent across colonies and habitats.     

SPEG Interacts with Myotubularin,and Its Deficiency Causes Centronuclear Myopathy with Dilated Cardiomyopathy

Centronuclear myopathies (CNMs) are characterized by muscle weakness and increased numbers of central nuclei within myofibers. X-linked myotubular myopathy, the most common severe form of CNM, is caused by mutations in MTM1, encoding myotubularin (MTM1), a lipid phosphatase. To increase our understanding of MTM1 function, we conducted a yeast two-hybrid screen to identify MTM1-interacting proteins. Striated muscle preferentially expressed protein kinase (SPEG), the product of SPEG complex locus (SPEG), was identified as an MTM1-interacting protein, confirmed by immunoprecipitation and immunofluorescence studies. SPEG knockout has been previously associated with severe dilated cardiomyopathy in a mouse model. Using whole-exome sequencing, we identified three unrelated CNM-affected probands, including two with documented dilated cardiomyopathy, carrying homozygous or compound-heterozygous SPEG mutations. SPEG was markedly reduced or absent in two individuals whose muscle was available for immunofluorescence and immunoblot studies. Examination of muscle samples from Speg-knockout mice revealed an increased frequency of central nuclei, as seen in human subjects. SPEG localizes in a double line, flanking desmin over the Z lines, and is apparently in alignment with the terminal cisternae of the sarcoplasmic reticulum. Examination of human and murine MTM1-deficient muscles revealed similar abnormalities in staining patterns for both desmin and SPEG. Our results suggest that mutations in SPEG, encoding SPEG, cause a CNM phenotype as a result of its interaction with MTM1. SPEG is present in cardiac muscle, where it plays a critical role; therefore, individuals with SPEG mutations additionally present with dilated cardiomyopathy.     

Proteomic analysis of human osteoarthritis synovial fluid

Background

Osteoarthritis is a chronic musculoskeletal disorder characterized mainly by progressive degradation of the hyaline cartilage. Patients with osteoarthritis often postpone seeking medical help, which results in the diagnosis being made at an advanced stage of cartilage destruction. Sustained efforts are needed to identify specific markers that might help in early diagnosis, monitoring disease progression and in improving therapeutic outcomes. We employed a multipronged proteomic approach, which included multiple fractionation strategies followed by high resolution mass spectrometry analysis to explore the proteome of synovial fluid obtained from osteoarthritis patients. In addition to the total proteome, we also enriched glycoproteins from synovial fluid using lectin affinity chromatography.

Results

We identified 677 proteins from synovial fluid of patients with osteoarthritis of which 545 proteins have not been previously reported. These novel proteins included ADAM-like decysin 1 (ADAMDEC1), alanyl (membrane) aminopeptidase (ANPEP), CD84, fibulin 1 (FBLN1), matrix remodelling associated 5 (MXRA5), secreted phosphoprotein 2 (SPP2) and spondin 2 (SPON2). We identified 300 proteins using lectin affinity chromatography, including the glycoproteins afamin (AFM), attractin (ATRN), fibrillin 1 (FBN1), transferrin (TF), tissue inhibitor of metalloproteinase 1 (TIMP1) and vasorin (VSN). Gene ontology analysis confirmed that a majority of the identified proteins were extracellular and are mostly involved in cell communication and signaling. We also confirmed the expression of ANPEP, dickkopf WNT signaling pathway inhibitor 3 (DKK3) and osteoglycin (OGN) by multiple reaction monitoring (MRM) analysis of osteoarthritis synovial fluid samples.

Conclusions

We present an in-depth analysis of the synovial fluid proteome from patients with osteoarthritis. We believe that the catalog of proteins generated in this study will further enhance our knowledge regarding the pathophysiology of osteoarthritis and should assist in identifying better biomarkers for early diagnosis.     

ISB News January 2010

ISB News

ISB News January 2010     

Determining the impact of scale insect honeydew, and invasive wasps and rodents, on the decomposer subsystem in a New Zealand beech forest

Relatively few studies have considered how aboveground invasive consumers influence decomposer communities. We investigated the potential effects of three types of animals on the decomposer subsystem in a floristically simple New Zealand Nothofagus forest. These animals are the native beech honeydew scale insect (Ultracoelostoma spp.) that secretes large amounts of sugar-rich honeydew that washes to the soil, invasive social wasps (Vespula spp.) that remove honeydew and prevent it from reaching the ground, and invasive rodents (the house mouse (Mus musculus) and ship rat (Rattus rattus)) that are predators of litter invertebrates. We performed a 4 years manipulative experiment involving addition of synthetic honeydew to the soil surface at amounts equal to that washed to the soil both in the absence and presence of wasps. All treatments were subjected to both exclusion and non-exclusion of rodents. Full honeydew addition influenced several components of the belowground community (both positively and negatively), and promoted fungi and fungal feeding fauna at the expense of bacteria and bacterial-feeders. The reduced addition of honeydew (representing effects of wasps) reversed some (but not all) effects of full honeydew addition. Rodents also influenced some belowground organisms, often reversing the effects of honeydew addition. The honeydew levels simulating wasp effects and the presence of rodents both greatly promoted humus carbon and nutrient storage relative to all other treatments, highlighting that invaders can alter soil carbon sequestration and nutrient capital. Our study points to invasive animals modifying the effects of a native animal on multiple components of the decomposer subsystem.