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181.
Morphological and metrical study suggested that seven human teeth from Tabun Cave, Israel were part of the upper dentition of a single, probably Neanderthal, individual renumbered as Tabun BC7. An enamel fragment gave ESR age estimates of 82+/-14 ka (early U-uptake) and 92+/-18 ka (linear uptake) and an age estimate of 90(+30)(-16) ka using U-series disequilibrium. Although metrical analyses suggested Neanderthal affinities, definitive assessment was difficult as the values often fell into the ranges of both Neanderthal and Levantine early modern human samples. Therefore, two further classification analyses were conducted (neural networks using self-organizing maps and homogeneity analysis). Both identify Tabun BC7 as a Neanderthal. Neural networks are a promising tool for paleoanthropological studies as they can provide reliable classifications even with incomplete data. 相似文献
182.
Garlanda C Di Liberto D Vecchi A La Manna MP Buracchi C Caccamo N Salerno A Dieli F Mantovani A 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(5):3119-3125
Toll IL-1R 8/single Ig IL-1-related receptor (TIR8/SIGIRR) is a member of the IL-1R family, expressed by epithelial tissues and immature dendritic cells, and is regarded as a negative regulator of TLR/IL-1R signaling. Tir8-deficient mice were rapidly killed by intranasal administration of low doses of Mycobacterium tuberculosis, despite controlling efficiently the number of viable bacilli in different organs. Tir8(-/-)-infected mice showed an increased number of neutrophils and macrophages in the lungs; however, mycobacteria-specific CD4 and CD8 T cells were similar in Tir8(-/-) and Tir8(+/+) mice. Exaggerated mortality of Tir8(-/-) mice was due to massive liver necrosis and was accompanied by increased levels of IL-1beta and TNF-alpha in lung mononuclear cells and serum, as well as by increased production of IL-1beta and TNF-alpha by M. tuberculosis-infected dendritic cells in vitro. Accordingly, blocking IL-1beta and TNF-alpha with a mix of anti-cytokine Abs, significantly prolonged survival of Tir8(-/-) mice. Thus, TIR8/SIGIRR plays a key role in damping inflammation and tissue damage in M. tuberculosis infection. 相似文献
183.
G protein beta gamma subunit interaction with the dynein light-chain component Tctex-1 regulates neurite outgrowth 总被引:1,自引:0,他引:1
Sachdev P Menon S Kastner DB Chuang JZ Yeh TY Conde C Caceres A Sung CH Sakmar TP 《The EMBO journal》2007,26(11):2621-2632
Tctex-1, a light-chain component of the cytoplasmic dynein motor complex, can function independently of dynein to regulate multiple steps in neuronal development. However, how dynein-associated and dynein-free pools of Tctex-1 are maintained in the cell is not known. Tctex-1 was recently identified as a Gbetagamma-binding protein and shown to be identical to the receptor-independent activator of G protein signaling AGS2. We propose a novel role for the interaction of Gbetagamma with Tctex-1 in neurite outgrowth. Ectopic expression of either Tctex-1 or Gbetagamma promotes neurite outgrowth whereas interfering with their function inhibits neuritogenesis. Using embryonic mouse brain extracts, we demonstrate an endogenous Gbetagamma-Tctex-1 complex and show that Gbetagamma co-segregates with dynein-free fractions of Tctex-1. Furthermore, Gbeta competes with the dynein intermediate chain for binding to Tctex-1, regulating assembly of Tctex-1 into the dynein motor complex. We propose that Tctex-1 is a novel effector of Gbetagamma, and that Gbetagamma-Tctex-1 complex plays a key role in the dynein-independent function of Tctex-1 in regulating neurite outgrowth in primary hippocampal neurons, most likely by modulating actin and microtubule dynamics. 相似文献
184.
Alfredo Saldaña Christopher H. Lusk Wilfredo L. Gonzáles Ernesto Gianoli 《Evolutionary ecology》2007,21(5):651-662
Unlike other species of the genus Blechnum, the fern Blechnum chilense occurs in a wide range of habitats in Chilean temperate rainforest, from shaded forest understories to abandoned clearings
and large gaps. We asked if contrasting light environments can exert differential selection on ecophysiological traits of
B. chilense. We measured phenotypic selection on functional traits related to carbon gain: photosynthetic capacity (A
max), dark respiration rate (R
d), water use efficiency (WUE), leaf size and leaf thickness in populations growing in gaps and understorey environments. We
assessed survival until reproductive stage and fecundity (sporangia production) as fitness components. In order to determine
the potential evolutionary response of traits under selection, we estimated the genetic variation of these traits from clonally
propagated individuals in common garden experiments. In gaps, survival of B. chilense was positively correlated with WUE and negatively correlated with leaf size. In contrast, survival in shaded understories
was positively correlated with leaf size. We found positive directional fecundity selection on WUE in gaps population. In
understories, ferns of lower R
d and greater leaf size showed greater fecundity. Thus, whereas control of water loss was optimized in gaps, light capture
and net carbon balance were optimized in shaded understories. We found a significant genetic component of variation in WUE,
R
d and leaf size. This study shows the potential for evolutionary responses to heterogeneous light environments in functional
traits of B. chilense, a unique fern species able to occupy a broad successional niche in Chilean temperate rainforest. 相似文献
185.
186.
Brault S Gobeil F Fortier A Honoré JC Joyal JS Sapieha PS Kooli A Martin E Hardy P Ribeiro-da-Silva A Peri K Lachapelle P Varma D Chemtob S 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,292(3):R1174-R1183
Oxidant stress plays a significant role in hypoxic-ischemic injury to the susceptible microvascular endothelial cells. During oxidant stress, lysophosphatidic acid (LPA) concentrations increase. We explored whether LPA caused cytotoxicity to neuromicrovascular cells and the potential mechanisms thereof. LPA caused a dose-dependent death of porcine cerebral microvascular as well as human umbilical vein endothelial cells; cell death appeared oncotic rather than apoptotic. LPA-induced cell death was mediated via LPA(1) receptor, because the specific LPA(1) receptor antagonist THG1603 fully abrogated LPA's effects. LPA decreased intracellular GSH levels and induced a p38 MAPK/JNK-dependent inducible nitric oxide synthase (NOS) expression. Pretreatment with the antioxidant GSH precursor N-acetyl-cysteine (NAC), as well as with inhibitors of NOS [N(omega)-nitro-l-arginine (l-NNA); 1400W], significantly prevented LPA-induced endothelial cell death (in vitro) to comparable extents; as expected, p38 MAPK (SB203580) and JNK (SP-600125) inhibitors also diminished cell death. LPA did not increase indexes of oxidation (isoprostanes, hydroperoxides, and protein nitration) but did augment protein nitrosylation. Endothelial cytotoxicity by LPA in vitro was reproduced ex vivo in brain and in vivo in retina; THG1603, NAC, l-NNA, and combined SB-203580 and SP600125 prevented the microvascular rarefaction. Data implicate novel properties for LPA as a modulator of the cell redox environment, which partakes in endothelial cell death and ensued neuromicrovascular rarefaction. 相似文献
187.
Corona-Rivera A Urbina-Cano P Bobadilla-Morales L Vargas-Lares Jde J Ramirez-Herrera MA Mendoza-Magaua ML Troyo-Sanroman R Diaz-Esquivel P Corona-Rivera JR 《Journal of applied genetics》2007,48(4):389-396
Curcumin is a phytochemical with antiinflammatory, antioxidant and anticarcinogenic activities. Apparently, curcumin is not genotoxic in vivo, but in vitro copper and curcumin interactions induce genetic damage. The aim of this study was to test if in vivo copper excess induces DNA damage measured by comet and micronucleus assays in the presence of curcumin. We tested 0.2% curcumin in Balb-C mice at normal (13 ppm) and high (65, 130 and 390 ppm) copper ion concentrations. The comet and micronucleus assays were performed 48 hr after chemical application. Comet tail length in animals treated with 0.2% curcumin was not significantly different from the control. Animals exposed to copper cations (up to 390 ppm) exhibited higher oxidative DNA damage. Curcumin reduced the DNA damage induced by 390 ppm copper. We observed statistically significant increase in damage in individuals exposed to 390 ppm copper versus the control or curcumin groups, which was lowered by the presence of curcumin. Qualitative data on comets evidenced that cells from individuals exposed to 390 ppm copper had longer tails (categories 3 and 4) than in 390 ppm copper + curcumin. A statistically significant increase in frequency of micronucleated erythrocytes (MNE/10000TE) was observed only in 390 ppm copper versus the control and curcumin alone. Also cytotoxicity measured as the frequency of polychromatic erythrocytes (PE/1000TE) was attributable to 390 ppm copper. The lowest cytotoxic effect observed was attributed to curcumin. In vivo exposure to 0.2% curcumin for 48 hr did not cause genomic damage, while 390 ppm copper was genotoxic, but DNA damage induced by 390 ppm copper was diminished by curcumin. Curcumin seems to exert a genoprotective effect against DNA damage induced by high concentrations of copper cations. The comet and micronucleus assays prove to be suitable tools to detect DNA damage by copper in the presence of curcumin. 相似文献
188.
189.
190.
Overexpression, purification and characterization of the Trichoderma atroviride endochitinase, Ech42, in Pichia pastoris 总被引:1,自引:0,他引:1
Pérez-Martínez AS De León-Rodríguez A Harris LJ Herrera-Estrella A Barba de la Rosa AP 《Protein expression and purification》2007,55(1):183-188
The endochitinase gene ech42 from Trichoderma atroviride was cloned and expressed in Pichia pastoris using a constitutive expression system. Over 98% of the recombinant protein was secreted into the culture medium as glycoprotein. A high endochitinase concentration, 186 mg/L with a specific enzyme activity of 14,128 Umg(-1) was produced. The optimal enzyme kinetic parameters for the recombinant protein were identical to those reported for the enzyme isolated from T. atroviride. The recombinant endochitinase possesses suitable features for biotechnological applications, such as activity at acidic pH and thermostability. 相似文献