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991.
Markus Lange Wolfgang W. Weisser Martin M. Gossner Esther Kowalski Manfred Türke Fernando Joner Carlos Roberto Fonseca 《Biodiversity and Conservation》2011,20(10):2133-2147
Land use intensification in forests is a main driver of global biodiversity loss. Although historical state of land use differs
between subtropical and temperate zones, gradients of land-use intensities similarly range from unmanaged to very intensively
managed forests. Irrespective of similar land use forces in both climate zones, comparative studies on land use effects are
still rare. Such studies are, however, promising in discovering more general impacts and geographical specifics of land use
intensification. We studied litter-dwelling invertebrates along a gradient of increasing land use intensity in subtropical
forests in Southern Brazil and temperate forests in Central Europe using similar sampling designs. Effects of land use intensity
on the entire community were analyzed on the level of orders and feeding guilds. In both climate zones a similar number of
individuals were caught when standardizes to 100 pitfall trap days, but taxa richness was higher in the subtropics. Moreover,
community composition differed between both climate zones. In both regions, land use intensity did not affect taxa richness,
but invertebrate abundance was affected in opposite ways; while increasing land use intensity resulted in a decrease of invertebrate
abundance in the subtropics, an increase was observed in the temperate zone and this was mostly consistent regarding different
feeding guilds. Management practices should take into account that the effect of land use intensity on biodiversity can differ
drastically among climatic regions. 相似文献
992.
Adauto Lima Cardoso Julio Cesar Pieczarka Eliana Feldberg Susana Suely Rodrigues Milhomem Thiago Moreira-Almeida Danillo dos Santos Silva Patrícia Corrêa da Silva Cleusa Yoshiko Nagamachi 《Reviews in Fish Biology and Fisheries》2011,21(3):613-621
Gymnotiformes are an important component of the Neotropical ichthyofauna and they are known for their ability to generate
and detect electrical discharges. Phylogenetic relationships of Gymnotiformes are still not well understood. However, the
monophyly of the superfamily Rhamphichthyoidea is well accepted, despite the position of tribe Steatogenini (Steatogenys, Hypopygus and Stegostenopos) within this superfamily is unclear. The genus Steatogenys includes three species that, together with Hypopygus and Stegostenopos, form tribe Steatogenini. Cytogenetic information is currently only available for Hypopygus lepturus. Here, we describe the karyotypes of Steatogenys elegans from four localities and S. duidae from two localities. S. elegans was found to have 2n = 50, ZZ/ZW (12m-sm/38st-a), while S. duidae had 2n = 50 (50m-sm). In S. elegans, constitutive heterochromatin (CH) was observed in the centromeric regions of all chromosomes, in the interstitial region
of 1q, and in two blocks of Wq. In S. duidae, CH was observed in the centromeric and pericentromeric regions of all chromosomes, and in the interstitial regions of 2q,
3q, 5q, and 7q. Nucleolar organizer regions (NORs) were identified in the distal regions of one chromosome pair in each species.
The CMA3 fluorochrome (specific to G-C rich regions) coincided with the NORs in both species, and with the HC of S. elegans except on chromosome pair 5 and the W. The DAPI fluorochrome (specific to A-T rich regions) coincided with the CH of both
species, and was very intense for chromosome pair 5 and the W of S. elegans. Our observations suggest that the ZZ/ZW system observed in S. elegans likely evolved through CH addition followed by a paracentric inversion. The chromosomal data described herein are consistent
with the phylogenetic hypothesis that tribe Steatogenini should be positioned within family Ramphychthyidae. 相似文献
993.
Cristina M. Monteiro Susana C. Fonseca Paula M. L. Castro F. Xavier Malcata 《Journal of applied phycology》2011,23(1):97-103
Aquatic environments often contain toxic heavy metals that may enter the food web via uptake by microalgae and eventually
cause severe poisoning problems at higher trophic levels. The effects of Cd and Zn cations upon growth of two native green
microalgal species, Scenedesmus obliquus and Desmodesmus pleiomorphus (previously isolated from a polluted site in Northern Portugal), were accordingly evaluated. Growth inhibition of the microalgal
cells was determined following exposure for 96 h to several initial concentrations of aqueous solutions of either of those
two metals. At the higher end of Cd and Zn experimental concentration ranges, a significant reduction in cell density was
observed in the cultures; EC50 values, calculated after fitting a Weibull model to the experimental data, were 0.058 and 1.92 mg L−1 for Cd and 16.99 and 4.87 mg L−1 for Zn in the case of S. obliquus and D. pleiomorphus, respectively. One observed that S. obliquus can tolerate higher Zn concentrations than D. pleiomorphus, but the reverse holds regarding exposure to Cd. 相似文献
994.
Priscila Vaz de Arruda Rita de Cássia Lacerda Brambilla Rodrigues Débora Danielle Virgínio da Silva Maria das Graças de Almeida Felipe 《Biodegradation》2011,22(4):815-822
The evaluation of hexose and pentose in pre-cultivation of Candida guilliermondii FTI 20037 yeast on xylose reductase (XR) and xylitol dehydrogenase (XDH) enzymes activities was performed during fermentation in sugarcane bagasse hemicellulosic hydrolysate. The xylitol production was evaluated by using cells previously growth in 30.0 gl?1 xylose, 30.0 gl?1 glucose and in both sugars mixture (30.0 gl?1 xylose and 2.0 gl?1 glucose). The vacuum evaporated hydrolysate (80 gl?1) was detoxificated by ion exchange resin (A-860S; A500PS and C-150-Purolite®). The total phenolic compounds and acetic acid were 93.0 and 64.9%, respectively, removed by the resin hydrolysate treatment. All experiments were carried out in Erlenmeyer flasks at 200 rpm, 30°C. The maximum XR (0.618 Umg Prot ?1 ) and XDH (0.783 Umg Prot ?1 ) enzymes activities was obtained using inoculum previously growth in both sugars mixture. The highest cell concentration (10.6 gl?1) was obtained with inoculum pre-cultivated in the glucose. However, the xylitol yield and xylitol volumetric productivity were favored using the xylose as carbon source. In this case, it was observed maximum xylose (81%) and acetic acid (100%) consumption. It is very important to point out that maximum enzymatic activities were obtained when the mixture of sugars was used as carbon source of inoculum, while the highest fermentative parameters were obtained when xylose was used. 相似文献
995.
Dhuru S Bhedi D Gophane D Hirbhagat K Nadar V More D Parikh S Dalal R Fonseca LC Kharas F Vadnal PY Vishwakarma RA Sivaramakrishnan H 《Bioorganic & medicinal chemistry letters》2011,21(12):3784-3787
Synthesis and anti-inflammatory activity of novel diarylheptanoids [5-hydroxy-1-phenyl-7-(pyridin-3-yl)-heptan-3-ones and 1-phenyl-7-(pyridin-3-yl)hept-4-en-3-ones] as inhibitors of tumor necrosis factor-α (TNF-α) production is described in the present article. The key reactions involve the formation of a β-hydroxyketone by the reaction of substituted 4-phenyl butan-2-ones with pyridine-3-carboxaldehyde in presence of LDA and the subsequent dehydration of the same to obtain the α,β-unsaturated ketones. Compounds 4i, 5b, 5d, and 5g significantly inhibit lipopolysaccharide (LPS)-induced TNF-α production from human peripheral blood mononuclear cells in a dose-dependent manner. Of note, the in vitro TNF-α inhibition potential of 5b and 5d is comparable to that of curcumin (a naturally occurring diarylheptanoid). Most importantly, oral administration of 4i, 5b, 5d, and 5g (each at 100 mg/kg) but not curcumin (at 100 mg/kg) significantly inhibits LPS-induced TNF-α production in BALB/c mice. Collectively, our findings indicate that these compounds may have potential therapeutic implications for TNF-α-mediated auto-immune/inflammatory disorders. 相似文献
996.
Charruau P Fernandes C Orozco-Terwengel P Peters J Hunter L Ziaie H Jourabchian A Jowkar H Schaller G Ostrowski S Vercammen P Grange T Schlötterer C Kotze A Geigl EM Walzer C Burger PA 《Molecular ecology》2011,20(4):706-724
The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago (ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern‐East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity. 相似文献
997.
Compartmentalization and ultrastructural alterations induced by chromium in aquatic macrophytes 总被引:1,自引:0,他引:1
Pedro A. Mangabeira Aluane S. Ferreira Alex-Alan F. de Almeida Val��ria F. Fernandes Emerson Lucena Vania L. Souza Alberto J. dos Santos J��nior Arno H. Oliveira Marie F. Grenier-Loustalot Fr��derique Barbier Delmira C. Silva 《Biometals》2011,24(6):1017-1026
The aim of the present study was to identify the sites of accumulation of Cr in the species of macrophytes that are abundant in the Cachoeira river, namely, Alternanthera philoxeroides, Borreria scabiosoides, Polygonum ferrugineum and Eichhornia crassipes. Plants were grown in nutritive solution supplemented with 0.25 and 50 mg l?1 of CrCl3·6H2O. Samples of plant tissues were digested with HNO3/HCl in a closed-vessel microwave system and the concentrations of Cr determined using inductively-coupled plasma mass spectrometry (ICP-MS). The ultrastructure of root, stem and leaf tissue was examined using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) in order to determine the sites of accumulation of Cr and to detect possible alterations in cell organelles induced by the presence of the metal. Chromium accumulated principally in the roots of the four macrophytes (8.6?C30 mg kg?1 dw), with much lower concentrations present in the stems and leaves (3.8?C8.6 and 0.01?C9.0 mg kg?1 dw, respectively). Within root tissue, Cr was present mainly in the vacuoles of parenchyma cells and cell walls of xylem and parenchyma. Alterations in the shape of the chloroplasts and nuclei were detected in A. philoxeroides and B. scabiosoides, suggesting a possible application of these aquatic plants as biomarkers from Cr contamination. 相似文献
998.
Rafael Y. Kuradomi Márcio A. Figueiredo Carlos F. C. Lanes Carlos E. da Rosa Daniela V. Almeida Rodrigo Maggioni Maeli D. P. Silva Luis F. Marins 《Transgenic research》2011,20(3):513-521
The aim of the present study was to analyse the morphology of white skeletal muscle in males and females from the GH-transgenic
zebrafish (Danio rerio) lineage F0104, comparing the expression of genes related to the somatotrophic axis and myogenesis. Histological analysis
demonstrated that transgenic fish presented enhanced muscle hypertrophy when compared to non-transgenic fish, with transgenic
females being more hypertrophic than transgenic males. The expression of genes related to muscle growth revealed that transgenic
hypertrophy is independent from local induction of insulin-like growth factor 1 gene (igf1). In addition, transgenic males exhibited significant induction of myogenin gene (myog) expression, indicating that myog may mediate hypertrophic growth in zebrafish males overexpressing GH. Induction of the
α-actin gene (acta1) in males, independently from transgenesis, also was observed. There were no significant differences in total protein content
from the muscle. Our results show that muscle hypertrophy is independent from muscle igf1, and is likely to be a direct effect of excess circulating GH and/or IGF1 in this transgenic zebrafish lineage. 相似文献
999.
Ribeiro NS Folgado J Fernandes PR Monteiro J 《Computer methods in biomechanics and biomedical engineering》2011,14(10):883-892
This paper describes the development of a computational model to calculate wear rates in total shoulder prostheses, for a 5-150 degrees arm abduction. Anatomical keeled and pegged prosthesis as well as reversed prosthesis were the studied implants. The bone models were built based on computed tomography (CT) images and using a computer aided design-based modelling pipeline. The finite element method was used to solve the contact problem between the surface of the polyethylene (PE) components and the corresponding articular component. The aim of this work was to determine linear and volumetric PE wear, for several radial mismatches, in conditions of pathological (rheumatoid arthritis) and non-pathological bone. Results showed that contact pressures and linear wear developed in anatomical prosthesis were higher than those visualised in reversed prosthesis. However, anatomical prosthesis exhibited a better volumetric wear performance. Moreover, our findings indicated higher values of volumetric wear in higher congruent models and on pathological bone conditions. 相似文献
1000.
de Oliveira KB Guembarovski RL Oda JM Mantovani MS Carrera CM Reiche EM Voltarelli JC da Silva do Amaral Herrera AC Watanabe MA 《Cytokine》2011,55(2):260-265
The role of chemokines has been extensively analyzed both in cancer risk and tumor progression. Among different cytokines, CXCR4 and its ligand CXCL12 have been recently subjected to a closer examination. The single-nucleotide polymorphism (SNP) rs1801157 (previously known as CXCL12-A/SDF1-3'A) in the CXCL12 gene and the relative expression of mRNA CXCL12 in peripheral blood were assessed in breast cancer patients, since the chemokine CXCL12 and its receptor CXCR4 regulate leukocyte trafficking and many essential biological processes, including tumor growth, angiogenesis and metastasis of different types of tumors. Genotyping was performed by PCR-RFLP (polymerase chain reaction followed by restriction fragment length polymorphism) using MspI restriction enzyme and the expression analyses by quantitative RT-PCR. No difference in GG genotype and allele A carrier frequencies were observed between breast cancer patients and healthy blood donors and nor when CXCL12 mRNA expression was assessed among patients with different tumor stages. However a significant difference was observed when CXCL12 mRNA relative expression was analyzed in breast cancer patients in accordance to the presence or absence of the CXCL12 rs1801157 allele A. Allele A breast cancer patients presented a mRNA CXCL12 expression about 2.1-fold smaller than GG breast cancer patients. Estrogen positive patients presenting CXCL12 allele A presented a significantly lower expression of CXCL12 in peripheral blood (p=0.039) than GG hormone positive patients. Our findings demonstrated that allele A is associated with low expression of CXCL12 in the peripheral blood from ER-positive breast cancer patients, which suggests implications on breast cancer clinical outcome. 相似文献