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891.
Liang Zhang Zhongyang Ding Peng Xu Yuhong Wang Zhenghua Gu Zhu Qian Guiyang Shi Kechang Zhang 《Biotechnology and Bioprocess Engineering》2011,16(3):457-461
Tyrosinase is a key enzyme in the biosynthesis of melanin, and the use of inhibitors against tyrosinase can prevent hyperpigmentation
by inhibiting enzymatic oxidation. However, the current use of tyrosine inhibitors is limited by their low activities and
high toxicities. The aim of the present research was to develop novel whitening agents, or tyrosinase-targeted medicine, from
a submerged culture of the fungus Ganoderma lucidum. Methyl lucidenate F was isolated from the ethanol-soluble-acidic components (ESACs) of G. lucidum, with the structure of ESACs elucidated via UV, LC-MS, and 13C-NMR spectral analysis. The tyrosinase inhibitory activity was measured using catechol as a substrate. Methyl lucidenate
F displayed uncompetitive inhibition of the potato tyrosinase activity, for which Lineweaver-Burk plots revealed a maximum
reaction rate (V
max) of 0.4367/min, Michaelis constant (K
m) of 6.765 mM and uncompetitive inhibition constant (K
i) of 19.22 μM. Meanwhile, methyl lucidenate F (tetra cyclic triterpenoid) exhibited high tyrosinase inhibitory activity, with
an IC50 of 32.23 μM. These results suggest that methyl lucidenate F may serve as a potential candidate for skin-whitening agents. 相似文献
892.
Non-target organism effects tests on Vip3A and their application to the ecological risk assessment for cultivation of MIR162 maize 总被引:1,自引:0,他引:1
Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) provide economic, environmental and health benefits by maintaining or increasing crop yields with fewer applications of
insecticide. To sustain these benefits, it is important to delay the evolution of insect resistance to the proteins, and to
ensure that the proteins do not harm non-target organisms, particularly those that may control secondary pests that would
otherwise flourish because of reduced insecticide applications. Vip3A is a Bt vegetative insecticidal protein that is active against lepidopterous pests. It has a different mode of action from other
proteins for control of Lepidoptera in current Bt crops, and when combined with these proteins, it should help to delay the evolution of pest resistance to Bt crops. This paper presents data on the effects of Vip3A on non-target organisms, and an ecological risk assessment of MIR162
maize, which expresses Vip3Aa20. Laboratory studies indicate few adverse effects of Vip3A to non-target organisms: 11 of 12
species tested showed no adverse effects when exposed to high concentrations of Vip3A relative to estimated exposures resulting
from cultivation of MIR162 maize. Daphnia magna exposed to Vip3Aa20 were unaffected in terms of survival or fecundity, but grew slightly more slowly than unexposed controls.
The data indicate that cultivation of MIR162 maize poses negligible risk to non-target organisms, and that crops producing
Vip3A are unlikely to adversely affect biological control organisms such that benefits from reduced insecticide applications
are lost. 相似文献
893.
The Brazilian Atlantic Forest is a Biodiversity Hotspot, yet many biological groups in this biome are poorly known. We compiled
information on the diversity of Atlantic Forest tiger moths (Arctiidae) and assessed the resemblance among localities, whether
arctiid assemblages are concordant with major vegetation types, and the importance of environmental factors in structuring
the variation among assemblages. Additionally, we developed a procedure composed of subsampling and procrustean analysis to
assess the robustness of the results from community composition ordinations when localities differ in species richness. To
do this, we built a database from specimens deposited in the ten most important Brazilian entomological collections, and mapped
species richness in one-degree latitude/longitude grid cells. We employed Principal Coordinates Analysis to assess similarities
among the best-sampled localities. We obtained 8,667 records including 1,193 species, representing 60 and 20% of the estimated
Brazilian and Neotropical faunas, respectively. Our subsampling procedure indicated that the ordination was not greatly affected
by differences in species richness, and was congruent with major vegetation types. Lowland localities on the seacoast were
quite distinct in species composition. A second group included localities in montane areas in the southeast part of the biome.
The last group included localities in the southern region and those with Araucaria forests, and was associated with long distances
from the ocean, even distribution of precipitation throughout the year, and large annual temperature ranges. 相似文献
894.
Gregory M. Peters Stephen Wiedemann Hazel V. Rowley Robyn Tucker Andrew J. Feitz Matthias Schulz 《The International Journal of Life Cycle Assessment》2011,16(5):431-441
Purpose
This paper describes part of the first detailed environmental life cycle assessment (LCA) of Australian red meat (beef and sheep meat) production. The study was intended to assist the methodological development of life cycle impact assessment by examining the feasibility of new indicators for natural resource management (NRM) issues relevant to soil management in agricultural LCA. This paper is intended to describe the NRM indicators directly related to agricultural soil chemistry. 相似文献895.
Borovsky Y Paran I 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(4):657-665
We previously identified fs10.1 as a major QTL controlling fruit shape (index of length to width) in an interspecific F2 cross of Capsicum annuum (round fruit) × C. chinense (elongated fruit) in pepper. To more precisely map and characterize the QTL, we constructed near-isogenic lines for fs10.1 and mapped it in a BC4F2 population. In this population, fs10.1 segregated as a Mendelian locus and mapped 0.3 cM away from the closest molecular marker. We further verified the effect
of fs10.1 in an F2 population from an independent cross between elongated- and conical-fruited parents. To identify additional allelic variation
at fruit shape loci, we screened an EMS-mutagenized population of the blocky-fruited cv. Maor and identified the mutant E-1654
with elongated fruit. This fruit shape mutation was mapped to the fs10.1 region and was determined to be allelic to the QTL. By measuring fruit shape of near-isogenic lines for fs10.1 during fruit development, we found that the shape of the fruit is determined primarily in the first 2 weeks after anthesis.
Histological measurements of cell size and cell shape in pericarp sections of fruits of the isogenic lines throughout fruit
development indicated that the shape of the fruit is determined primarily by cell shape and that the development of fruit
shape is correlated with cell shape. 相似文献
896.
Brzuszkiewicz E Thürmer A Schuldes J Leimbach A Liesegang H Meyer FD Boelter J Petersen H Gottschalk G Daniel R 《Archives of microbiology》2011,193(12):883-891
The genome sequences of two Escherichia coli O104:H4 strains derived from two different patients of the 2011 German E. coli outbreak were determined. The two analyzed strains were designated E. coli GOS1 and GOS2 (German outbreak strain). Both isolates comprise one chromosome of approximately 5.31 Mbp and two putative plasmids. Comparisons of the 5,217
(GOS1) and 5,224 (GOS2) predicted protein-encoding genes with various E. coli strains, and a multilocus sequence typing analysis revealed that the isolates were most similar to the entero-aggregative
E. coli (EAEC) strain 55989. In addition, one of the putative plasmids of the outbreak strain is similar to pAA-type plasmids of
EAEC strains, which contain aggregative adhesion fimbrial operons. The second putative plasmid harbors genes for extended-spectrum
β-lactamases. This type of plasmid is widely distributed in pathogenic E. coli strains. A significant difference of the E. coli GOS1 and GOS2 genomes to those of EAEC strains is the presence of a prophage encoding the Shiga toxin, which is characteristic
for enterohemorrhagic E. coli (EHEC) strains. The unique combination of genomic features of the German outbreak strain, containing characteristics from
pathotypes EAEC and EHEC, suggested that it represents a new pathotype Entero-Aggregative-Haemorrhagic E
scherichia
c
oli (EAHEC). 相似文献
897.
The Effect of Sterilization Methods on the Physical Properties of Silk Sericin Scaffolds 总被引:1,自引:0,他引:1
Protein-based biomaterials respond differently to sterilization methods. Since protein is a complex structure, heat, or irradiation
may result in the loss of its physical or biological properties. Recent investigations have shown that sericin, a degumming
silk protein, can be successfully formed into a 3-D scaffolds after mixing with other polymers which can be applied in skin
tissue engineering. The objective of this study was to investigate the effectiveness of ethanol, ethylene oxide (EtO) and
gamma irradiation on the sterilization of sericin scaffolds. The influence of these sterilization methods on the physical
properties such as pore size, scaffold dimensions, swelling and mechanical properties, as well as the amount of sericin released
from sericin/polyvinyl alcohol/glycerin scaffolds, were also investigated. Ethanol treatment was ineffective for sericin scaffold
sterilization whereas gamma irradiation was the most effective technique for scaffold sterilization. Moreover, ethanol also
caused significant changes in pore size resulting from shrinkage of the scaffold. Gamma-irradiated samples exhibited the highest
swelling property, but they also lost the greatest amount of weight after immersion for 24 h compared with scaffolds obtained
from other sterilization methods. The results of the maximum stress test and Young’s modulus showed that gamma-irradiated
and ethanol-treated scaffolds are more flexible than the EtO-treated and untreated scaffolds. The amount of sericin released,
which was related to its collagen promoting effect, was highest from the gamma-irradiated scaffold. The results of this study
indicate that gamma irradiation should have the greatest potential for sterilizing sericin scaffolds for skin tissue engineering. 相似文献
898.
899.
Luciana Mollo Marina C. M. Martins Vanessa Fátima Oliveira Catarina C. Nievola Rita de Cássia L. Figueiredo-Ribeiro 《Plant Cell, Tissue and Organ Culture》2011,107(1):141-149
The imperial bromeliad Alcantarea imperialis grows naturally on rocky outcrops (‘inselbergs’) in regions where daily temperatures vary from 5 to 40°C. As carbohydrate
metabolism is altered in response to cold, it could lead to reprogramming of the metabolic machinery including the increase
in levels of metabolites that function as osmolytes, compatible solutes, or energy sources in order to maintain plant homeostasis.
The aim of this study was to evaluate the effects of different temperatures on plant growth and non-structural carbohydrates
in plants of A. imperialis adapted to low temperature. Seedlings of A. imperialis were grown in vitro under a 12-h photoperiod with four different day/night temperature cycles: 5/5°C, 15/15°C, 15/30°C (dark/light)
and 30/30°C. Plants were also cultivated at 26°C in ex vitro conditions for comparison. The results showed an inverse relationship
between temperature and germination time and no differences in the percentage of germination. Plants maintained for 9 months
at 15°C presented a reduced number of leaves and roots, and a dry mass four times lower than plants grown at 30°C. Sugar content
was higher in plants grown at 15°C than at 30°C. However, the highest amount of total sugar was found in plants growing under
warm day/cold night conditions. Myo-inositol, glucose, fructose and sucrose were found predominantly under high temperatures, while under low temperatures,
sucrose was apparently replaced by trehalose, raffinose and stachyose. Starch content was highest in plants grown under high
temperatures. The lowest starch content was detected under low temperatures, suggesting its conversion into soluble carbohydrates
to protect the plants against cold. These results indicated that low temperature retarded growth of A. imperialis and increased sugar levels, mainly trehalose, thus suggesting that these sugar compounds could be involved in cold tolerance. 相似文献
900.
Gustavo Ciudad Isaac Reyes Milko A. Jorquera Laura Azócar Lukas Y. Wick Rodrigo Navia 《World journal of microbiology & biotechnology》2011,27(11):2505-2512
A novel three-phase solid–gas–liquid bioreactor (SGLB) concept using gaseous alcohol and liquid rapeseed oil with immersed
microorganisms overlying a nutrient agar phase (solid) is proposed for biodiesel (fatty acid alkyl esters, FAAE) production
based on the high hydrophobicity and negative surface charge showed by the fungi Rhizopus oryzae. This novel bioreactor was thought to increase oil bioavailability and decrease alcohol toxicity for effective microbial
growth, reaching high yields of FAAE production without any pretreatment. High growth rates were reached for R. oryzae using a SGLB simultaneously reaching a high FAAE production yield, up to 50% using methanol and up to 70% using ethanol at
144 h of incubation at 20°C. To compare the effect of gaseous alcohol, the same experiments were carried out in a three-phase
solid–liquid–liquid bioreactor (SLLB), where the alcohol was added in liquid phase, showing significant R. oryzae growth but no FAAE formation. This suggests that the inhibitory effect of alcohol is more significant in lipase activity
than in R. oryzae growth, and the use of alcohol in gaseous phase may decrease both of them. The experimental procedure using SGLB showed that
when R. oryzae is maintained alive, it can catalyze at the same time the hydrolysis, esterification and transesterification of triglycerides
from rapeseed oil, but its activity strongly depends on the used growth media. Therefore, the application of gaseous alcohol
coupled with R. oryzae as immobilized whole cell catalysts may be a potential alternative to the use of commercial lipases for biodiesel production. 相似文献