Hoverflies (Diptera: Syrphidae) benefit from a cultivation of the bioenergy crop Silphium perfoliatum L. (Asteraceae) depending on larval feeding type,landscape composition and crop management

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Greenhouse gas emissions and global warming potential of traditional and diversified tropical rice rotation systems

Global rice agriculture will be increasingly challenged by water scarcity, while at the same time changes in demand (e.g. changes in diets or increasing demand for biofuels) will feed back on agricultural practices. These factors are changing traditional cropping patterns from double‐rice cropping to the introduction of upland crops in the dry season. For a comprehensive assessment of greenhouse gas (GHG) balances, we measured methane (CH₄)/nitrous oxide (N₂O) emissions and agronomic parameters over 2.5 years in double‐rice cropping (R‐R) and paddy rice rotations diversified with either maize (R‐M) or aerobic rice (R‐A) in upland cultivation. Introduction of upland crops in the dry season reduced irrigation water use and CH₄ emissions by 66–81% and 95–99%, respectively. Moreover, for practices including upland crops, CH₄ emissions in the subsequent wet season with paddy rice were reduced by 54–60%. Although annual N₂O emissions increased two‐ to threefold in the diversified systems, the strong reduction in CH₄ led to a significantly lower (P < 0.05) annual GWP (CH₄ + N₂O) as compared to the traditional double‐rice cropping system. Measurements of soil organic carbon (SOC) contents before and 3 years after the introduction of upland crop rotations indicated a SOC loss for the R‐M system, while for the other systems SOC stocks were unaffected. This trend for R‐M systems needs to be followed as it has significant consequences not only for the GWP balance but also with regard to soil fertility. Economic assessment showed a similar gross profit span for R‐M and R‐R, while gross profits for R‐A were reduced as a consequence of lower productivity. Nevertheless, regarding a future increase in water scarcity, it can be expected that mixed lowland–upland systems will expand in SE Asia as water requirements were cut by more than half in both rotation systems with upland crops.     

Distribution of melatonin MT1 receptor immunoreactivity in human retina.

Melatonin is synthesized in the pineal gland and retina during the night. Retinal melatonin is believed to be involved in local cellular modulation and in regulation of light-induced entrainment of circadian rhythms. The present study provides the first immunohistochemical evidence for the localization of melatonin 1a-receptor (MT1) in human retina of aged subjects. Ganglion, amacrine, and photoreceptor cells expressed MT1. In addition, MT1 immunoreactivity was localized to cell processes in the inner plexiform layer and to central vessels of the retina, as well as to retinal vessels but not to ciliary or choroidal vessels. These results support a variety of cellular and vascular effects of melatonin in the human retina. Preliminary evidence from patients with Alzheimer's disease (AD) revealed increased MT1 immunoreactivity in ganglion and amacrine cells, as well as in vessels. In AD cases photoreceptor cells were degenerated and showed low MT1 expression.     

Effects after inhalation of (1-->3)-beta-D-glucan and relation to mould exposure in the home

BACKGROUND: Damp conditions indoors favour the growth of microorganisms, and these contain several agents that may cause inflammation when inhaled. Moulds contain a polyglucose in their cell wall, defined as (1-->3)-beta-D-glucan, exhibiting effects on inflammatory cells. AIM: The aim of the present study was to evaluate whether an inhalation challenge to purified (1-->3)-beta-D-glucan (grifolan) in humans could induce effects on inflammatory markers in blood, and to evaluate whether the reactions were related to the home exposure to (1-->3)-beta-D-glucan. METHODS: Seventeen subjects in homes with high levels of airborne (1-->3)-beta-D-glucan (G-high) and 18 subjects in homes with low levels of (1-->3)-beta-D-glucan (G-low) underwent two randomised, double-blind inhalation challenges, one to (1-->3)-beta-D-glucan suspended in saline and one to saline alone. A blood sample was taken before and after the challenges, and differential cell count, granulocyte enzymes in serum and the secretion of cytokines from peripheral blood mononuclear cells (PBMC) were measured. RESULTS: Inhalation challenge with (1-->3)-beta-D-glucan induced a decrease in the secretion of tumour necrosis factor alpha from endotoxin-stimulated PBMC in the G-high group as well as in the G-low group. In the G-high group, the inhalation of (1-->3)-beta-D-glucan induced an increase in blood lymphocytes that was significantly different from the saline-induced effect. CONCLUSIONS: The results suggest that an inhalation challenge to (1-->3)-beta-D-glucan has an effect on inflammatory cells and this effect may be related to a chronic exposure to moulds at home.     

rbcL sequences support exclusion ofRetzia,Desfontainia, andNicodemia from theGentianales

The taxonomic positions ofRetzia, Desfontainia, andNicodemia have been much discussed, and all three genera have been included inLoganiaceae (Gentianales). We have made a cladistic analysis ofrbcL gene sequences to determine the relationships of these taxa toGentianales. Four newrbcL sequences are presented; i.e., ofRetzia, Desfontainia, Diervilla (Caprifoliaceae), andEuthystachys (Stilbaceae). Our results show thatRetzia, Desfontainia, andNicodemia are not closely related toLoganiaceae or theGentianales. Retzia is most closely related toEuthystachys and is better included inStilbaceae. The positions ofDesfontainia andNicodemia are not settled, butDesfontainia shows affinity for theDipsacales s.l. andNicodemia for theLamiales s.l.     

Hypothermic protection of the ischemic heart via alterations in apoptotic pathways as assessed by gene array analysis.

Hypothermia improves resistance to ischemia in the cardioplegia-arrested heart. This adaptive process produces changes in specific signaling pathways for mitochondrial proteins and heat-shock response. To further test for hypothermic modulation of other signaling pathways such as apoptosis, we used various molecular techniques, including cDNA arrays. Isolated rabbit hearts were perfused and exposed to ischemic cardioplegic arrest for 2 h at 34 degrees C [ischemic group (I); n = 13] or at 30 degrees C before and during ischemia [hypothermic group (H); n = 12]. Developed pressure, the maximum first derivative of left ventricular pressure, oxygen consumption, and pressure-rate product (P < 0.05) recovery were superior in H compared with in I during reperfusion. mRNA expression for the mitochondrial proteins, adenine translocase and the beta-subunit of F1-ATPase, was preserved by hypothermia. cDNA arrays revealed that ischemia altered expression of 13 genes. Hypothermia modified this response to ischemia for eight genes, six related to apoptosis. A marked, near fivefold increase in transformation-related protein 53 in I was virtually abrogated in H. Hypothermia also increased expression for the anti-apoptotic Bcl-2 homologue Bcl-x relative to I but decreased expression for the proapoptotic Bcl-2 homologue bak. These data imply that hypothermia modifies signaling pathways for apoptosis and suggest possible mechanisms for hypothermia-induced myocardial protection.     

A shift towards succinate-producing Prevotella in the ruminal microbiome challenged with monensin

The time-resolved impact of monensin on the active rumen microbiome was studied in a rumen-simulating technique (Rusitec) with metaproteomic and metabolomic approaches. Monensin treatment caused a decreased fibre degradation potential that was observed by the reduced abundance of proteins assigned to fibrolytic bacteria and glycoside hydrolases, sugar transporters and carbohydrate metabolism. Decreased proteolytic activities resulted in reduced amounts of ammonium as well as branched-chain fatty acids. The family Prevotellaceae exhibited increased resilience in the presence of monensin, with a switch of the metabolism from acetate to succinate production. Prevotella species harbour a membrane-bound electron transfer complex, which drives the reduction of fumarate to succinate, which is the substrate for propionate production in the rumen habitat. Besides the increased succinate production, a concomitant depletion of methane concentration was observed upon monensin exposure. Our study demonstrates that Prevotella sp. shifts its metabolism successfully in response to monensin exposure and Prevotellaceae represents the key bacterial family stabilizing the rumen microbiota during exposure to monensin.     

Distinct effects on heparan sulfate structure by different active site mutations in NDST-1

Heparan sulfate polymerization and modification take place in the Golgi compartment. The modification reactions are initiated by glucosaminyl N-deacetylase/N-sulfotransferase (NDST), a bifunctional enzyme that removes N-acetyl groups from selected N-acetyl-d-glucosamine units followed by N-sulfation of the generated free amino groups. Four isoforms of NDST have been identified. NDST-1 and -2 have a wide and largely overlapping tissue distribution, but it is not known if they can act on the same heparan sulfate chain. We have introduced point mutations into NDST-1 cDNA, which selectively destroy the N-deacetylase or N-sulfotransferase activity of the enzyme [Wei, Z., and Swiedler, S. J. (1999) J. Biol. Chem. 274, 1966-70 and Sueyoshi, T., et al. (1998) FEBS Lett. 433, 211-4]. Stable 293 cell lines expressing the NDST-1 mutants were then generated. Structural analyses of heparan sulfate synthesized by these cells and by cells overexpressing wild-type NDST-1 demonstrate that the N-deacetylation step is not only prerequisite but also rate-limiting, determining the degree of N-sulfation. Transfection of mutant NDST-1 lacking N-deacetylase activity had no effect on heparan sulfate sulfation, while cells expressing wild-type enzyme or NDST-1 lacking N-sulfotransferase activity both resulted in the production of oversulfated heparan sulfate. Since no increase in the amount of N-unsubstituted glucosamine residues was seen after transfection of the mutant lacking N-sulfotransferase activity, the results also suggest that two different enzyme molecules can act on the same glucosamine unit. In addition, we show that oversulfation of heparan sulfate produced by cells tranfected with wild-type NDST-1 or the mutant lacking N-sulfotranferase activity results in decreased sulfation of chondroitin sulfate.     

Identification of Chondroitin Sulfate Linkage Region Glycopeptides Reveals Prohormones as a Novel Class of Proteoglycans

Vertebrates produce various chondroitin sulfate proteoglycans (CSPGs) that are important structural components of cartilage and other connective tissues. CSPGs also contribute to the regulation of more specialized processes such as neurogenesis and angiogenesis. Although many aspects of CSPGs have been studied extensively, little is known of where the CS chains are attached on the core proteins and so far, only a limited number of CSPGs have been identified. Obtaining global information on glycan structures and attachment sites would contribute to our understanding of the complex proteoglycan structures and may also assist in assigning CSPG specific functions. In the present work, we have developed a glycoproteomics approach that characterizes CS linkage regions, attachment sites, and identities of core proteins. CSPGs were enriched from human urine and cerebrospinal fluid samples by strong-anion-exchange chromatography, digested with chondroitinase ABC, a specific CS-lyase used to reduce the CS chain lengths and subsequently analyzed by nLC-MS/MS with a novel glycopeptide search algorithm. The protocol enabled the identification of 13 novel CSPGs, in addition to 13 previously established CSPGs, demonstrating that this approach can be routinely used to characterize CSPGs in complex human samples. Surprisingly, five of the identified CSPGs are traditionally defined as prohormones (cholecystokinin, chromogranin A, neuropeptide W, secretogranin-1, and secretogranin-3), typically stored and secreted from granules of endocrine cells. We hypothesized that the CS side chain may influence the assembly and structural organization of secretory granules and applied surface plasmon resonance spectroscopy to show that CS actually promotes the assembly of chromogranin A core proteins in vitro. This activity required mild acidic pH and suggests that the CS-side chains may also influence the self-assembly of chromogranin A in vivo giving a possible explanation to previous observations that chromogranin A has an inherent property to assemble in the acidic milieu of secretory granules.Chondroitin sulfates (CS)¹ are complex polysaccharides present at cell surfaces and in extracellular matrices. The polysaccharides belong to a subclass of glycosaminoglycans (GAGs) and are covalently linked to various core proteins to form CS-proteoglycans (CSPGs), each with differences in the protein structures and/or numbers of CS side chains. Apart from their structural role in cartilage, CSPGs contribute to the regulation of a diverse set of biological processes such as neurogenesis, growth factor signaling, angiogenesis, and morphogenesis (1–5). Although the molecular basis of CSPGs functions remains elusive, accumulating evidence suggests that the underlying activities relate to selective ligand binding to discrete structural variants of the polysaccharides. Thus, the current strategy for understanding the biological role of CSPGs aims to identify selective CS polysaccharide–ligand interactions. However, information on the number of CS-chains and their specific attachment site(s) on any given core protein is often scarce which limits our functional understanding of CSPGs.The biosynthesis of GAGs occurs in the endoplasmic reticulum and Golgi compartments and is initiated by the enzymatic addition of a beta-linked xylose (Xyl) to a Ser residue of the core protein. The sequential addition of two galactose residues (Gal) and a glucuronic acid (GlcA) onto the growing saccharide chain completes the formation of a tetrasaccharide linkage region (GlcAβ3Galβ3Galβ4XylβSer). This part of the biosynthesis is the same for CS and heparan sulfate (HS). However, for CS the biosynthesis continues with the addition of an N-acetylgalactosamine (GalNAcβ3), whereas HS biosynthesis continues with the addition of an N-acetylglucosamine (GlcNAcα4) (6). The CS-chains are thereafter elongated through the addition of repeating units of GlcA and GalNAc and are further modified by the addition of specifically positioned sulfate groups (7). Certain features of the core protein seem to influence if a certain Ser residue is selected for GAG attachment and whether CS or HS will be synthesized, but the selection mechanism is largely unknown. Sequence analysis of previously known GAG-substituted core proteins reveals that the glycosylated serine residues are usually flanked by a glycine residue (-SG-), and are associated with a cluster of acidic residues in close proximity (8). This motif may assist in the prediction of potential GAG-sites of core proteins; however, the use of such strategy is ambiguous because proteoglycans may also contain unoccupied motifs or motifs that are occasionally occupied (9).Glycoproteomics strategies have recently appeared that provide site-specific information of N- and O-glycans. Such strategies are typically based on a specific enrichment of glycopeptides and a subsequent analysis with nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) (10). By further developing this concept for proteoglycans (11), we have now analyzed CSPG linkage region glycopeptides of human samples, which enabled us to identify 13 novel human CSPGs in addition to 13 already established CSPGs. Urine and cerebrospinal fluid (CSF) samples were trypsinized and CS glycopeptides were enriched using strong anion exchange (SAX) chromatography. The CS chains were depolymerized with chondroitinase ABC, generating free disaccharides and a residual hexameric structure composed of the linkage region and a GlcA-GalNAc disaccharide dehydrated on the terminal GlcA residue (12). MS/MS analysis provided the combined sequencing of the residual hexasaccharide and of the core peptide.