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排序方式: 共有276条查询结果,搜索用时 15 毫秒
51.
Trishul Artham M. Sudhakar R. Venkatesan C. Madhavan Nair K.V.G.K. Murty Mukesh Doble 《International biodeterioration & biodegradation》2009,63(7):884-890
Commercial synthetic polymers namely Polycarbonate (PC), Low density polyethylene (LDPE), High density polyethylene (HDPE), and Polypropylene (PP) coupons were immersed for a period of 12 months (Feb 2006 – Feb 2007) in Bay of Bengal, East coast, India. Samples were retrieved every month and the extent of biofouling and biodegradation were monitored. Biofouling was found to depend not only on the season but also on the chemical nature of the polymer. Surface energy of all the four polymers is positively correlated with fouling only at the initial stages (three months) while surface roughness had a negative correlation. The later increased during the study period. Total suspended solids and organic matter were more abundant on HDPE, followed by PP and LDPE, indicating that among polyolefins hydrophobic surfaces (lower surface energy) favor biofouling over one year. Maximum fouling was observed on polycarbonate during initial three months. Chlorophyll a showed a decreasing trend during the study, as secondary foulers such as Balanus amphitrite, were dominant after the monsoon (6th month in the present study). Maximum weight loss was seen in LDPE (1.9%), followed by that in HDPE (1.6%), PC (0.69%) and finally in PP (0.65%) samples in the 12 months time period. FTIR spectra of PC displayed a decrease in carbonate carbonyl index, while an initial increase and a decrease in carbonyl index of polyolefins as a function of time indicated biodegradation. 相似文献
52.
An overview of sustainability assessment methodologies 总被引:3,自引:0,他引:3
Sustainability indicators and composite index are increasingly recognised as a useful tool for policy making and public communication in conveying information on countries and corporate performance in fields such as environment, economy, society, or technological improvement. By visualizing phenomena and highlighting trends, sustainability indicators simplify, quantify, analyse and communicate otherwise complex and complicated information.There are number of initiatives working on indicators and frameworks for sustainable development (SD). This article provides an overview various sustainability indices applied in policy practice. The paper also compiles the information related to sustainability indices formulation strategy, scaling, normalisation, weighting and aggregation methodology. 相似文献
53.
Nishant Junnarkar D. Srinivas Murty Nikhil S. Bhatt Datta Madamwar 《World journal of microbiology & biotechnology》2006,22(2):163-168
Summary Samples collected from various effluent-contaminated soils in the vicinities of dyestuff manufacturing units of Ahmedabad, India, were studied for screening and isolation of organisms capable of decolorizing textile dyes. A novel bacterial consortium was selected on the basis of rapid decolorization of Direct Red 81 (DR 81), which was used as model dye. The bacterial consortium exhibited 90% decolorization ability within 35 h. Maximum rate of decolorization was observed when starch (0.6 g l−1) and casein (0.9 g l−1) were supplemented in the medium. Decolorization of DR 81 was monitored by high performance thin layer chromatography, which indicated that dye decolorization was due to its degradation into unidentified intermediates. The optimum dye-decolorizing activity of the culture was observed at pH 7.0 and incubation temperature of 37 °C. Maximum dye-decolorizing efficiency was observed at 200 mg l−1 concentration of DR 81. The bacterial consortium had an ability to decolorize nine other structurally different azo dyes. 相似文献
54.
Nine white-rot fungal strains were screened for biodecolourization of brilliant green, cresol red, crystal violet, congo red
and orange II. Dichomitus squalens, Phlebia fascicularia and P. floridensis decolourized all of the dyes on solid agar medium and possessed better decolourization ability than Phanerochaete chrysosporium when tested in nitrogen-limited broth medium. Journal of Industrial Microbiology & Biotechnology (2002) 28, 201–203 DOI: 10.1038/sj/jim/7000222
Received 12 July 2001/ Accepted in revised form 22 October 2001 相似文献
55.
56.
B J Carter V S Murty K S Reddy S N Wang S M Hecht 《The Journal of biological chemistry》1990,265(8):4193-4196
Previous studies of Fe-bleomycin-mediated DNA cleavage have established that the bithiazole moiety + C-terminal substituent of bleomycin are required for DNA binding, while the metal binding domain is responsible for O2 activation. Although recent studies have indicated that the metal binding domain also participates in DNA unwinding, and in determining the sequence and strand selectivity of DNA cleavage, no study has defined the structural domain that bears primary responsibility for the observed pattern of bleomycin-mediated DNA degradation. Presently, by the use of four synthetic analogs of bleomycin demethyl A2 having the functional domains connected by rigid spacers of varying lengths, the source of DNA cleavage specificity has been determined. When the four analogs cleaved 242- and 127-base pair 5'-32P-end-labeled DNA restriction fragments containing isolated Fe-bleomycin cleavage sites, all four produced cleavage at the same preferred sites. Because the (oligo)glycine spacers altered the distance between the domains by as much as 14 A, the identical cleavage patterns argue that the primary determinant of sequence specificity for these analogs is the metal binding domain. 相似文献
57.
M. A. Valera Matos B. R. Murty 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,69(4):353-359
Summary The mutation breeding program of alteration in plant type in two local Sorghum varieties resulted in several productive mutants of which 16 are far superior to the parents CRP, CBA and recommended hybrids. An earlier analysis of leaf area and photosynthetic efficiency revealed a diversity of mechanisms between mutants of the same yield group. Differences in the transfer of nutrients from leaf to the panicle were also indicated. Further analysis of the partition of nutrients in the panicle, flag leaf and rachis for N, P and K revealed that most of the mutants are at least equal to the parent in grain N but are superior in N content of flag leaf and rachis. Similarly, three mutants had a higher P content in grain than CRP and all other mutants were equal to CRP. Two mutants had more P in the flag leaf but this was not reflected in the grain. However, no differences were observed for the K content in the flag leaf, grain and rachis. The interrelations of the nutrients in different plant parts suggest that each mutant has a different pattern of nutrient accumulation and transfer. It could be concluded that selection for flag leaf N and P can improve grain N and P. There was no negative association between N and P accumulation in different plant parts. No adverse association was observed for other combinations. A study on the grain digestability of the mutants confirmed that the quality of the protein was not adversely affected in this material. This study indicated that simultaneous improvement of grain yield and grain N, P and K can be obtained even among the few mutants generated in this breeding program contrary to the belief of some cereal breeders that grain yield and its N content have a major negative association limiting the improvement of yield and protein content simultaneously.This study was part of a project supplied by IAEA, Vienna 相似文献
58.
Non-K-region polycyclic aromatic hydrocarbon (PAH) o-quinones represent alternative metabolites of PAH trans-dihydro diol proximate carcinogens. These PAH o-quinones react readily with glutathione and N-acetyl-L-cysteine, and these adducts may be responsible for their detoxication. Reactions between benzo[a]pyrene-7,8-dione and either N-acetyl-L-cysteine or glutathione gave three predominant products which were purified by semipreparative reverse-phase high-pressure liquid chromatography and characterized by homonuclear two-dimensional correlation spectroscopy (COSY). The first product corresponded to a Michael type, 1,4-addition product isolated at the level of quinone oxidation. The second product converted to the first and is a presumptive 1,4-addition product isolated at the level of hydroquinone oxidation. The third product was 7,8-dihydroxybenzo[a]pyrene (a hydroquinone) and was formed as a result of the reductive potential of the thiol. Additional proof for the catechol structure was obtained by its conversion to its diacetate and its identity with authentic 7,8-diacetoxybenzo[a]pyrene. The structures of these adducts and intermediates confirm that thiol addition involves formation of the ketol and rearrangement to give a catechol followed by oxidation to yield the quinone adduct. No evidence was obtained for the formation of either bisphenol or bisglutathionyl adducts. The COSY spectra provide the first complete structure of a benzo[a]pyrenyl-peptide conjugate. 相似文献
59.
Summary It is known that consanguinity reduces the chances of maternal-foetal incompatibility but it is not known whether inbreeding influences the expression of the effects of such incompatibility. This paper investigates and finds evidence for an interaction between inbreeding and AB0 blood group incompatibility on the expression of neonatal mortality, sibship precocious mortality, neonatal jaundice, asphyxia, and sex ratio, through screening of 3923 consecutive newborns. Inbreeding and incompatibility individually showed variable effects on the above parameters, but their interaction was such that, in the presence of inbreeding, incompatibility reduced the incidence/relative risk of all the above factors. Such a uniform negative interaction was presumed to be due to homozygosity of some pleiotropic genes caused by inbreeding. 相似文献
60.
Phylogenetic evidence for horizontal transmission of group I introns in the nuclear ribosomal DNA of mushroom-forming fungi 总被引:7,自引:3,他引:4
Group I introns were discovered inserted at the same position in the
nuclear small-subunit ribosomal DNA (nuc-ssu-rDNA) in several species of
homobasidiomycetes (mushroom-forming fungi). Based on conserved intron
sequences, a pair of intron-specific primers was designed for PCR
amplification and sequencing of intron-containing rDNA repeats. Using the
intron-specific primers together with flanking rDNA primers, a PCR assay
was conducted to determine presence or absence of introns in 39 species of
homobasidiomycetes. Introns were confined to the genera Panellus,
Clavicorona, and Lentinellus. Phylogenetic analyses of nuc-ssu-rDNA and
mitochondrial ssu-rDNA sequences suggest that Clavicorona and Lentinellus
are closely related, but that Panellus is not closely related to these. The
simplest explanation for the distribution of the introns is that they have
been twice independently gained via horizontal transmission, once on the
lineage leading to Panellus, and once on the lineage leading to Lentinellus
and Clavicorona. BLAST searches using the introns from Panellus and
Lentinellus as query sequences retrieved 16 other similar group I introns
of nuc-ssu-rDNA and nuclear large-subunit rDNA (nuc-lsu-rDNA) from fungal
and green algal hosts. Phylogenetic analyses of intron sequences suggest
that the mushroom introns are monophyletic, and are nested within a clade
that contains four other introns that insert at the same position as the
mushroom introns, two from different groups of fungi and two from green
algae. The distribution of host lineages and insertion sites among the
introns suggests that horizontal and vertical transmission, homing, and
transposition have been factors in intron evolution. As distinctive,
heritable features of nuclear rDNAs in certain lineages, group I introns
have promise as phylogenetic markers. Nevertheless, the possibility of
horizontal transmission and homing also suggest that their use poses
certain pitfalls.
相似文献