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81.
Livestock manures are broadly used in agriculture to improve soil quality. However, manure application can increase the availability of organic carbon, thereby facilitating methane (CH4) production. Cattle and swine manures are expected to have different CH4 emission characteristics in rice paddy soil due to the inherent differences in composition as a result of contrasting diets and digestive physiology between the two livestock types. To compare the effect of ruminant and non-ruminant animal manure applications on CH4 emissions and methanogenic archaeal diversity during rice cultivation (June to September, 2009), fresh cattle and swine manures were applied into experimental pots at 0, 20 and 40 Mg fresh weight (FW) ha−1 in a greenhouse. Applications of manures significantly enhanced total CH4 emissions as compared to chemical fertilization, with cattle manure leading to higher emissions than swine manure. Total organic C contents in cattle (466 g kg−1) and swine (460 g kg−1) manures were of comparable results. Soil organic C (SOC) contents were also similar between the two manure treatments, but dissolved organic C (DOC) was significantly higher in cattle than swine manure. The mcrA gene copy numbers were significantly higher in cattle than swine manure. Diverse groups of methanogens which belong to Methanomicrobiaceae were detected only in cattle-manured but not in swine-manured soil. Methanogens were transferred from cattle manure to rice paddy soils through fresh excrement. In conclusion, cattle manure application can significantly increase CH4 emissions in rice paddy soil during cultivation, and its pretreatment to suppress methanogenic activity without decreasing rice productivity should be considered. 相似文献
82.
Biofouling in marine aquaculture is a specific problem where both the target culture species and/or infrastructure are exposed to a diverse array of fouling organisms, with significant production impacts. In shellfish aquaculture the key impact is the direct fouling of stock causing physical damage, mechanical interference, biological competition and environmental modification, while infrastructure is also impacted. In contrast, the key impact in finfish aquaculture is the fouling of infrastructure which restricts water exchange, increases disease risk and causes deformation of cages and structures. Consequently, the economic costs associated with biofouling control are substantial. Conservative estimates are consistently between 5-10% of production costs (equivalent to US$ 1.5 to 3 billion yr(-1)), illustrating the need for effective mitigation methods and technologies. The control of biofouling in aquaculture is achieved through the avoidance of natural recruitment, physical removal and the use of antifoulants. However, the continued rise and expansion of the aquaculture industry and the increasingly stringent legislation for biocides in food production necessitates the development of innovative antifouling strategies. These must meet environmental, societal, and economic benchmarks while effectively preventing the settlement and growth of resilient multi-species consortia of biofouling organisms. 相似文献
83.
Yan-Hui Liu David Wylie Jia Zhao Raymond Cure Collette Cutler Susan Cannon-Carlson Xiaoyu Yang Tattanahalli L. Nagabhushan Birendra N. Pramanik 《Analytical biochemistry》2011,408(1):105
The isoforms Iso-2, Iso-3, and Iso-4 of Escherichia coli-derived recombinant human interferon alpha-2b (rhIFN α-2b), generated by posttranslational modifications of the protein during fermentation, present a major problem in terms of purification and the yield of the drug substance. We report here the structural characterization of these isoforms by mass spectrometry (MS) methods. An extensive MS study was conducted on Iso-4, which is composed of up to 75% of the in-process IFN, and on the native rhIFN α-2b. The trypsin-digested peptide mixtures generated from the two samples were analyzed by liquid chromatography (LC)–MS, and targeted peptides were further studied by LC–tandem MS (triple quadrupole mass spectrometer), high-resolution MSn (LTQ Orbitrap), and matrix-assisted laser desorption/ionization MS (MALDI–MS). The structure of Iso-4 was elucidated as a novel pyruvic acid ketimine derivative of the N-terminal cysteine (Cys1) of IFN α-2b, where the disulfide bond between Cys1 and Cys98 was fully reduced and the other disulfide bond pair, Cys29-ss-Cys138, was partially reduced. Similarly, Iso-2 was identified as a correctly disulfide-folded rhIFN α-2b with acetylation on Cys1, and Iso-3 was identified as an S-glutathionylated form (Cys98) of partially reduced rhIFN α-2b that was pyruvated on Cys1. Based on the characterization work, a reproducible conversion procedure was successfully implemented to convert Iso-4 to rhIFN α-2b. 相似文献
84.
Anusha Krishnan Gautam Kumar Pramanik Santosh V. Revadi Vignesh Venkateswaran Renee M. Borges 《PloS one》2014,9(12)
In a nursery pollination mutualism, we asked whether environmental factors affected reproduction of mutualistic pollinators, non-mutualistic parasites and seed production via seasonal changes in plant traits such as inflorescence size and within-tree reproductive phenology. We examined seasonal variation in reproduction in Ficus racemosa community members that utilise enclosed inflorescences called syconia as nurseries. Temperature, relative humidity and rainfall defined four seasons: winter; hot days, cold nights; summer and wet seasons. Syconium volumes were highest in winter and lowest in summer, and affected syconium contents positively across all seasons. Greater transpiration from the nurseries was possibly responsible for smaller syconia in summer. The 3–5°C increase in mean temperatures between the cooler seasons and summer reduced fig wasp reproduction and increased seed production nearly two-fold. Yet, seed and pollinator progeny production were never negatively related in any season confirming the mutualistic fig–pollinator association across seasons. Non-pollinator parasites affected seed production negatively in some seasons, but had a surprisingly positive relationship with pollinators in most seasons. While within-tree reproductive phenology did not vary across seasons, its effect on syconium inhabitants varied with season. In all seasons, within-tree reproductive asynchrony affected parasite reproduction negatively, whereas it had a positive effect on pollinator reproduction in winter and a negative effect in summer. Seasonally variable syconium volumes probably caused the differential effect of within-tree reproductive phenology on pollinator reproduction. Within-tree reproductive asynchrony itself was positively affected by intra-tree variation in syconium contents and volume, creating a unique feedback loop which varied across seasons. Therefore, nursery size affected fig wasp reproduction, seed production and within-tree reproductive phenology via the feedback cycle in this system. Climatic factors affecting plant reproductive traits cause biotic relationships between plants, mutualists and parasites to vary seasonally and must be accorded greater attention, especially in the context of climate change. 相似文献
85.
Anindita Mitra Arnab Pramanik Subhas Chandra Santra Pradip Kumar Sen Joydeep Mukherjee 《World journal of microbiology & biotechnology》2011,27(7):1679-1688
No investigation has been done to identify ecological factors selecting for broad-spectrum antimicrobial activity of actinomycetes
in the estuaries. Previously, we established that, in the Sundarbans (the world’s largest tidal mangrove forest), high antagonistic potential (AP) sampling sites were influenced by tides, while
the low AP sites were not. We now report molecular phylogenetic analysis, morphological, physiological and biochemical characteristics
of actinomycetes of high AP sites. The effects of soil organic carbon, nitrogen and ionic content (which strongly influenced
AP) on the strength and spectrum of activity of the isolates were also studied in shake flasks. Molecular phylogenetic analysis
showed sequences of our strains to be 96–99% similar to the 16S rDNA sequences of Streptomyces. Results showed variation among sporophore sizes, ornamentation and number of spores. Jaccard’s similarity coefficients of
the isolates varied from 0.512 to 0.884 indicating disparity in the biochemical and physiological characteristics, possibly
due to spatial separation of the sampling sites. Top soil in the intertidal zone of estuaries is generated from settling and
consolidation of fluid mud and Streptomyces would be expected to produce broad-spectrum antimicrobials in such virgin soil. Isolates should be collected from the narrow
band between the mean high and low tide marks to maximize chances of finding broad-spectrum activity. Considering the study
on nutritional requirements vis-à-vis the field studies, it was concluded that results of this investigation corroborated
the field observations where soil nitrogen, rather than organic carbon or ionic concentration, played a major role in determining
the antimicrobial spectrum. 相似文献
86.
I Tabas L L Chen J W Clader A T McPhail D A Burnett P Bartner P R Das B N Pramanik M S Puar S J Feinmark 《The Journal of biological chemistry》1990,265(14):8042-8051
Acyl-coenzyme A (CoA):cholesterol acyltransferase (ACAT) catalyzes the intracellular fatty acid esterification of cholesterol and is thought to play a key role in lipoprotein metabolism and atherogenesis. Herein we describe the purification and characterization of a novel pentacyclic triterpene ester from rabbit liver that has ACAT inhibitory activity. The inhibitor was purified by a combination of silicic acid chromatography and preparative thin layer chromatography. The compound inhibited both rabbit and rat liver microsomal ACAT activity with an IC50 = 20 microM. The lipid did not inhibit fatty acid incorporation into triglycerides, diglycerides, monoglycerides, or phospholipids nor did it inhibit plasma lecithin:cholesterol acyltransferase activity. However, rat liver microsomal acyl-CoA:retinol acyltransferase activity was inhibited by the terpene ester. Kinetic data are consistent with a mechanism in which ACAT is inhibited by the compound in an irreversible manner. The subcellular fractionation pattern of both ACAT activity and the ACAT inhibitor were similar in rabbit liver (both were approximately equally distributed in membranes that pelleted at 10,000 X g and 100,000 X g). A lipid with similar properties to the rabbit liver inhibitor was found in many other rabbit tissues, including adrenal and spleen, as well as in human liver. Rat liver did not contain this lipid. Structural analysis by NMR, mass spectrometry, and x-ray crystallography indicated that the rabbit liver inhibitor was a fatty acid ester (mostly stearate) of a pentacyclic triterpene acid. The carbon skeleton of the triterpene moiety is a new member of the olean-12-ene triterpene family. Both the negatively charged carboxylic acid group of the triterpene moiety and the esterified fatty acid group were necessary for the ACAT-inhibitory activity of the triterpene ester. Lastly, we present preliminary data which, together with the structural homology of the rabbit triterpene with known plant compounds, suggest the hypothesis that the triterpene moiety of the rabbit ACAT inhibitor arises from dietary absorption of a plant triterpene. 相似文献
87.
M Baltscheffsky P Nyrén A Strid A Pramanik 《Biochemical and biophysical research communications》1988,151(2):878-882
PMS-dependent photophosphorylation in bundle sheath chloroplasts isolated from Zea mays was monitored by using a continuous method. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and venturicidin were shown to inhibit the ATP-synthesis. Venturicidin has been shown to inhibit ATP-formation in both mesophyll and bundle sheath chloroplasts. In contrast to the case in mesophyll chloroplasts, FMN was not able to promote photophosphorylation in bundle sheath chloroplasts. The effects of other cofactors and inhibitors on the ATP-synthesis in bundle sheath chloroplasts are shown. No photoinduced synthesis of inorganic pyrophosphate was seen, neither in bundle sheath chloroplasts, nor in mesophyll chloroplasts. 相似文献
88.
Cytoplasmic polysomal and non-polysomal mRNA-associated proteincomplexes were isolated from, and characterized in, developingsomatic and zygotic embryos of alfalfa (Medicago sativa L.).35S-methionine-labelled intact embryos were irradiated withultraviolet light (UV) in situ to cross-link mRNA and proteinsoccurring within one bond length, and the polysomal and non-polysomalfractions were extracted. Then the mRNA-protein complexes wereisolated from the fractions and separated using two cycles ofaffinity chromatography on an oligo(dT)-cellulose column. Followingdigestion with RNase A and T1 and micrococcal nuclease, mRNA-associatedproteins were separated by SDS-PAGE. Several polypeptides of 15150 kDa were associated withthe polysomal and non-polysomal (ribonucleoprotein, mRNP) fractionsof alfalfa embryos after UV-cross-linking. Many of the polypeptidesassociated with the polysomal and non-polysomal mRNAs were qualitativelysimilar, although their concentration in the two fractions wasdifferent. However, some developmentally stage-specific polypeptideswere found to be associated with the non-polysomal mRNA fractionduring the early stages of embryogenesis (precotyledonary) ofsomatic embryos. Thus the presence of mRNPs during embryogenesishas been demonstrated, and proteins intimately associated withthe mRNAs identified. Key words: Embryogenesis, translational control, protein synthesis, messenger ribonucleoproteins, alfalfa (Medicago sativa L.) 相似文献
89.
Characterization of a soluble stable human cytomegalovirus protease and inhibition by M-site peptide mimics. 下载免费PDF全文
R L LaFemina K Bakshi W J Long B Pramanik C A Veloski B S Wolanski A I Marcy D J Hazuda 《Journal of virology》1996,70(7):4819-4824
The human cytomegalovirus (HCMV) protease is a potential target for antiviral chemotherapeutics; however, autoprocessing at internal sites, particularly at positions 143 and 209, hinders the production of large quantities of stable enzyme for either screening or structural studies. Using peptides encompassing the sequence of the natural M-site substrate (P5-P5', GVVNA/SCRLA), we previously demonstrated that substitution of glycine for valine at the P3 position in the substrate abrogates processing by the recombinant protease in vitro. We now demonstrate that introduction of the V-to-G substitution in the P3 positions of the two major internal processing sites, positions 143 and 209, in the mature HCMV protease renders the enzyme stable to autoprocessing. When expressed in Escherichia coli, the doubly substituted protease was produced almost exclusively as the 30-kDa full-length protein. The full-length V141G, V207G (V-to-G changes at positions 141 and 207) protease was purified as a soluble protein by a simple two-step procedure, ammonium sulfate precipitation followed by DEAE ion-exchange chromatography, resulting in 10 to 15 mg of greater than 95% pure enzyme per liter. The stabilized enzyme was characterized kinetically and was indistinguishable from the wild-type recombinant protease, exhibiting Km and catalytic constant values of 0.578 mM and 13.18/min, respectively, for the maturation site (M-site) peptide substrate, GVVNASCRLARR (underlined residues indicate additions to or substitutions from peptides derived from the wild-type substrate). This enzyme was also used to perform inhibition studies with a series of truncated and/or substituted maturation site peptides. Short nonsubstrate M-site-derived peptides were demonstrated to be competitive inhibitors of cleavage in vitro, and these analyses defined amino acids VVNA, P4 through P1 in the substrate, as the minimal substrate binding and recognition sequence for the HCMV protease. 相似文献
90.