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991.
Charlene Cavalheiro de Menezes Aracélli Gnatta Dorneles Rita Leal Sperotto Marta Medeiros Frescura Duarte Maria Rosa Chitolina Schetinger Vania Lúcia Loro 《Neurochemical research》2009,34(7):1255-1260
This study aimed to determine whether patients with aseptic and bacterial meningitis presented alterations in oxidative stress
parameters of cerebrospinal fluid (CSF). A total of 30 patients were used in the research. The CSF oxidative stress status
has been evaluated through many parameters, such as lipid peroxidation through thiobarbituric acid reactive substances (TBARS)
and antioxidant defense systems such as superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and ascorbic acid. TBARS levels, SOD and GST activity increase in aseptic meningitis
and in bacterial meningitis. The ascorbic acid concentration increased significantly in patients with both meningitis types.
The reduced glutathione levels were reduced in CSF of patients with aseptic and bacterial meningitis. In present study we
may conclude that oxidative stress contributes at least in part to the severe neurological dysfunction found in meningitis. 相似文献
992.
Kazunori Sato 《Population Ecology》2009,51(3):411-418
In this paper, we investigate a spatially explicit metapopulation model with Allee effects. We refer to the patch occupancy
model introduced by Levins (Bull Entomol Soc Am 15:237–240, 1969) as a spatially implicit metapopulation model, i.e., each local patch is either occupied or vacant and a vacant patch can
be recolonized by a randomly chosen occupied patch from anywhere in the metapopulation. When we transform the model into a
spatially explicit one by using a lattice model, the obtained model becomes theoretically equivalent to a “lattice logistic
model” or a “basic contact process”. One of the most popular or standard metapopulation models with Allee effects, developed
by Amarasekare (Am Nat 152:298–302, 1998), supposes that those effects are introduced formally by means of a logistic equation. However, it is easier to understand
the ecological meaning of associating Allee effects with this model if we suppose that only the logistic colonization term
directly suffers from Allee effects. The resulting model is also well defined, and therefore we can naturally examine it by
Monte Carlo simulation and by doublet and triplet decoupling approximation. We then obtain the following specific features
of one-dimensional lattice space: (1) the metapopulation as a whole does not have an Allee threshold for initial population
size even when each local population follows the Allee effects; and (2) a metapopulation goes extinct when the extinction
rate of a local population is lower than that in the spatially implicit model. The real ecological metapopulation lies between
two extremes: completely mixing interactions between patches on the one hand and, on the other, nearest neighboring interactions
with only two nearest neighbors. Thus, it is important to identify the metapopulation structure when we consider the problems
of invasion species such as establishment or the speed of expansion. 相似文献
993.
994.
Takashi Kitagawa Shingo Kimura Hideaki Nakata Harumi Yamada Akira Nitta Yoshikazu Sasai Hideharu Sasaki 《Environmental Biology of Fishes》2009,84(2):193-196
The habitat and movements of a Pacific bluefin tuna were investigated by reanalyzing archival tag data with sea surface temperature
data. During its trans-Pacific migration to the eastern Pacific, the fish took a direct path and primarily utilized waters,
in the Subarctic Frontal Zone (SFZ). Mean ambient temperature during the trans-Pacific migration was 14.5 ± 2.9 (°C ± SD),
which is significantly colder than the waters typically inhabited by bluefin tuna in their primary feeding grounds in the
western and eastern Pacific (17.6 ± 2.1). The fish moved rapidly through the colder water, and the heat produced during swimming
and the thermoconservation ability of bluefin tuna likely enabled it to migrate through the cold waters of the SFZ. 相似文献
995.
Toll-like receptor expression in normal ovary and ovarian tumors 总被引:1,自引:0,他引:1
Mingfu Zhou Molly M. McFarland-Mancini Holly M. Funk Nader Husseinzadeh Taofic Mounajjed Angela F. Drew 《Cancer immunology, immunotherapy : CII》2009,58(9):1375-1385
Recent studies have implicated inflammation in the initiation and progression of ovarian cancer, though the mechanisms underlying
this effect are still not clear. Toll-like receptors (TLRs) allow immune cells to recognize pathogens and to trigger inflammatory
responses. Tumor cell expression of TLRs can promote inflammation and cell survival in the tumor microenvironment. Here we
sought to characterize the expression of TLRs in normal human ovaries, benign and malignant ovarian tumors from patients,
and in established ovarian tumor cell lines. We report that TLR2, TLR3, TLR4, and TLR5 are strongly expressed on the surface
epithelium of normal ovaries. In contrast to previous studies of uterus and endocervix, we found no cyclic variation in TLR
expression occurred in murine ovaries. TLR2, TLR3, TLR4, and TLR5 are expressed in benign conditions, epithelial tumors, and
in ovarian cancer cell lines. Variable expression of TLR6 and TLR8 was seen in benign and malignant epithelium of some patients,
while expression of TLR1, TLR7, and TLR9 was weak. Normal and malignant ovarian stroma were negative for TLR expression. Vascular
endothelial cells, macrophages, and occasional fibroblasts in tumors were positive. Functional activity for TLRs was demonstrated
by stimulation of cell lines with specific ligands and subsequent activation and translocation of NFκB and release of the
proinflammatory cytokines interleukin-6 and CCL-2. These studies demonstrate expression of multiple TLRs in the epithelium
of normal ovaries and in ovarian tumor cells, and may indicate a mechanism by which epithelial tumors manipulate inflammatory
pathways to facilitate tumor progression. 相似文献
996.
Steffen Harzsch Carsten H. G. Müller Verena Rieger Yvan Perez Silvia Sintoni Christian Sardet Bill Hansson 《Zoomorphology》2009,128(1):53-73
The enigmatic arrow worms (Chaetognatha) are marine carnivores and among the most abundant planktonic organisms. Their phylogenetic
position has been heavily debated for a long time. Most recent molecular studies still provide a diverging picture and suggest
arrow worms to be some kind of basal protostomes. In an effort to understand the organization of the nervous system in this
clade for a broad comparison with other Metazoa we analysed the ultrastructure of the ventral nerve centre in Spadella cephaloptera by transmission electron microscopy. We were able to identify six different types of neurons in the bilateral somata clusters
by means of the cytoplasmic composition (regarding the structure of the neurite and soma including the shape and eu-/heterochromatin
ratio within the nucleus) as well as the size and position of these neurons. Furthermore, our study provides new insights
into the neuropil composition of the ventral nerve centre and several other fine structural features. Our second goal was
to examine if individually identifiable neurons are present in the ventral nerve centres of four chaetognath species, Sagitta setosa, Sagitta enflata, Pterosagitta draco, and Spadella cephaloptera. For that purpose, we processed whole mount specimens of these species for immunolocalization of RFamide-related neuropeptides
and analysed them with confocal laser-scanning microscopy. Our experiments provide evidence for the interspecific homology
of individual neurons in the ventral nerve centres of these four chaetognath species suggesting that the potential to generate
serially arranged neurons with individual identities is part of their ground pattern. 相似文献
997.
Antonio Di Franco Agnese Marchini Pasquale Baiata Marco Milazzo Renato Chemello 《Biodiversity and Conservation》2009,18(5):1201-1217
Scuba diving is now one of the major form of commercial use of marine protected areas (MPAs) around the world and the control
of its potential impacts on the marine environment represents a fundamental key to manage this recreational activity in highly
dived areas. A potential tool to tackle such issues has been thought to be the definition of a value of recreational carrying
capacity of an area, but this approach has been rarely considered management-effective. Therefore, the first step for effectively
managing scuba-diving should be ‘bottom-up’: characterizing the benthic communities potentially affected by diving and evaluating
their vulnerability. Aim of this paper is to propose a tool to define an index of vulnerability for dive trails (STVI: scuba
trail vulnerability index). This has taken into consideration both physical and biological features of each trail. All the
considered features are represented by non-quantitative variables, because either they are purely qualitative or their quantitative
measurement is impractical. The management of such qualitative information and its translation into a formal methodology was
performed by means of fuzzy logic, which has been repeatedly proposed as a powerful technique to develop indices of environmental
quality. The approach adopted in this study provided a useful tool for the preliminary assessment of the potential vulnerability
of benthic assemblages to scuba-diving and may represent an alternative method to the assessment of carrying capacity. The
application of this index will enable management strategies for potentially reducing the degradation of benthic organisms/assemblages,
and allowing a sustainable use of MPAs. 相似文献
998.
Chen-Xi Hu Hui Huang Li Zhang You Huang Zhu-Fang Shen Ke-Di Cheng Guan-Hua Du Ping Zhu 《Biotechnology letters》2009,31(7):979-984
Dipeptidyl peptidase (DPP) IV inhibitors provide a new strategy for the treatment of type 2 diabetes. Human DPP-IV gene was
cloned from differentiated Caco-2 cells and expressed in Pichia pastoris. The recombinant enzyme was used in a new system for screening of DPP-IV inhibitors. By high throughput screening, a novel
compound (W5188) was identified from 75,000 compounds with an IC50 of 6.5 μM. This method is highly reproducible and reliable for discovery of DPP-IV inhibitors as shown by Z′ value of 0.73
and S/N ratio of 6.89. 相似文献
999.
Microbial production of 2,3-butanediol from Jerusalem artichoke tubers by <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> 总被引:1,自引:0,他引:1
Li-Hui Sun Xu-Dong Wang Jian-Ying Dai Zhi-Long Xiu 《Applied microbiology and biotechnology》2009,82(5):847-852
2,3-Butanediol is one of the promising bulk chemicals with wide applications. Its fermentative production has attracted great
interest due to the high end concentration. However, large-scale production of 2,3-butanediol requires low-cost substrate
and efficient fermentation process. In the present study, 2,3-butanediol production by Klebsiella pneumoniae from Jerusalem artichoke tubers was successfully performed, and various technologies, including separate hydrolysis and fermentation
(SHF) and simultaneous saccharification and fermentation (SSF), were investigated. The concentration of target products reached
81.59 and 91.63 g/l, respectively after 40 h in batch and fed-batch SSF processes. Comparing with fed-batch SHF, the fed-batch
SSF provided 30.3% higher concentration and 83.2% higher productivity of target products. The results showed that Jerusalem
artichoke tuber is a favorable substrate for 2,3-butanediol production, and the application of fed-batch SSF for its conversion
can result in a more cost-effective process. 相似文献
1000.
Raimondi S Roncaglia L De Lucia M Amaretti A Leonardi A Pagnoni UM Rossi M 《Applied microbiology and biotechnology》2009,81(5):943-950
Twenty-two strains of Bifidobacterium, representative of eight major species of human origin, were screened for their ability to transform the isoflavones daidzin
and daidzein. Most of the strains released the aglycone from daidzin and 12 gave yields higher than 90%. The kinetics of growth,
daidzin consumption, and daidzein production indicated that the hydrolytic activity occurred during the growth. The supernatant
of the majority of the strains did not release the aglycone from daidzin, suggesting that cell-associated β-glucosidases (β-Glu)
are mainly responsible for the metabolism of soybean glyco-conjugates. Cell-associated β-Glu was mainly intracellular and
significantly varied among the species and the strains. The lack of β-Glu was correlated with the inability to hydrolyze daidzin.
Although S-equol production by anaerobic intestinal bacteria has been established, information on S-equol-producing bifidobacteria
is contradictory. In this study, 22 bifidobacteria failed to transform daidzein into reduced metabolites under all the experimental
conditions, excluding any role in the reductive pathway of daidzein toward the production of S-equol. These results suggest
that selected probiotic strains of Bifidobacterium can be used to speed up the release of daidzein, improving its bioavailability for absorption by colonic mucosa and/or biotransformation
to S-equol by other intestinal microorganisms. 相似文献