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91.
Travis Longcore Hannah L. Aldern John F. Eggers Steve Flores Lesly Franco Eric Hirshfield-Yamanishi Laina N. Petrinec Wilson A. Yan André M. Barroso 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1667)
Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods. 相似文献
92.
93.
Patrick L Cable J Potts D Ignace D Barron-Gafford G Griffith A Alpert H Van Gestel N Robertson T Huxman TE Zak J Loik ME Tissue D 《Oecologia》2007,151(4):704-718
Global climate models predict that in the next century precipitation in desert regions of the USA will increase, which is
anticipated to affect biosphere/atmosphere exchanges of both CO2 and H2O. In a sotol grassland ecosystem in the Chihuahuan Desert at Big Bend National Park, we measured the response of leaf-level
fluxes of CO2 and H2O 1 day before and up to 7 days after three supplemental precipitation pulses in the summer (June, July, and August 2004).
In addition, the responses of leaf, soil, and ecosystem fluxes of CO2 and H2O to these precipitation pulses were also evaluated in September, 1 month after the final seasonal supplemental watering event.
We found that plant carbon fixation responded positively to supplemental precipitation throughout the summer. Both shrubs
and grasses in watered plots had increased rates of photosynthesis following pulses in June and July. In September, only grasses
in watered plots had higher rates of photosynthesis than plants in the control plots. Soil respiration decreased in supplementally
watered plots at the end of the summer. Due to these increased rates of photosynthesis in grasses and decreased rates of daytime
soil respiration, watered ecosystems were a sink for carbon in September, assimilating on average 31 mmol CO2 m−2 s−1 ground area day−1. As a result of a 25% increase in summer precipitation, watered plots fixed eightfold more CO2 during a 24-h period than control plots. In June and July, there were greater rates of transpiration for both grasses and
shrubs in the watered plots. In September, similar rates of transpiration and soil water evaporation led to no observed treatment
differences in ecosystem evapotranspiration, even though grasses transpired significantly more than shrubs. In summary, greater
amounts of summer precipitation may lead to short-term increased carbon uptake by this sotol grassland ecosystem. 相似文献
94.
Norbury R Travis MJ Erlandsson K Waddington W Ell PJ Murphy DG 《Hormones and behavior》2007,51(2):249-257
Estrogen Therapy (ET) may protect against age-related cognitive decline and neuropsychiatric disorders (e.g. Alzheimer's disease). The biological basis for this putative neuroprotective effect is not fully understood, but may include modulation of cholinergic systems. Cholinergic dysfunction has been implicated in age-related memory impairment and Alzheimer's disease. However, to date no one has investigated the effect of long-term ET on brain cholinergic muscarinic receptor aging, and related this to cognitive function. We used Single Photon Emission Tomography (SPET) and (R,R)[(123)I]-I-QNB, a novel ligand with high affinity for m(1)/m(4) muscarinic receptors, to examine the effect of long-term ET and age on brain m(1)/m(4) receptors in healthy females. We included 10 younger premenopausal subjects and 22 postmenopausal women; 11 long-term ET users (all treated following surgical menopause) and 11 ET never-users (surgical menopause, n=2). Also, verbal memory and executive function was assessed in all postmenopausal subjects. Compared to young women, postmenopausal women (ET users and never-users combined) had significantly lower muscarinic receptor density in all brain regions examined. ET users also had higher muscarinic receptor density than ET never-users in all the brain regions, and this reached statistical significance in left striatum and hippocampus, lateral frontal cortex and thalamus. Moreover, in ET users, (R,R)[(123)I]-I-QNB binding in left hippocampus and temporal cortex was significantly positively correlated with plasma estradiol levels. We also found evidence for improved executive function in ET users as compared to ET never-users. However, there was no significant relationship between receptor binding and cognitive function within any of the groups. In healthy postmenopausal women use of long-term ET is associated with reduced age-related differences in muscarinic receptor binding, and this may be related to serum estradiol levels. 相似文献
95.
Chen L Maures TJ Jin H Huo JS Rabbani SA Schwartz J Carter-Su C 《Molecular endocrinology (Baltimore, Md.)》2008,22(2):454-476
Previous work showed that the adapter protein SH2B adapter protein 1beta (SH2B1) (SH2-B) binds to the activated form of the nerve growth factor (NGF) receptor TrkA and is critical for both NGF-dependent neurite outgrowth and maintenance. To identify SH2B1beta-regulated genes critical for neurite outgrowth, we performed microarray analysis of control PC12 cells and PC12 cells stably overexpressing SH2B1beta (PC12-SH2B1beta) or the dominant-negative SH2B1beta(R555E) [PC12-SH2B1beta(R555E)]. NGF-induced microarray expression of Plaur and Mmp10 genes was greatly enhanced in PC12-SH2B1beta cells, whereas NGF-induced Plaur and Mmp3 expression was substantially depressed in PC12-SH2B1beta(R555E) cells. Plaur, Mmp3, and Mmp10 are among the 12 genes most highly up-regulated after 6 h of NGF. Their protein products [urokinase plasminogen activator receptor (uPAR), matrix metalloproteinase 3 (MMP3), and MMP10] lie in the same pathway of extracellular matrix degradation; uPAR has been shown previously to be critical for NGF-induced neurite outgrowth. Quantitative real-time PCR analysis revealed SH2B1beta enhancement of NGF induction of all three genes and the suppression of NGF induction of all three when endogenous SH2B1 was reduced using short hairpin RNA against SH2B1 and in PC12-SH2B1beta(R555E) cells. NGF-induced levels of uPAR and MMP3/10 and neurite outgrowth through Matrigel (MMP3-dependent) were also increased in PC12-SH2B1beta cells. These results suggest that SH2B1beta stimulates NGF-induced neuronal differentiation at least in part by enhancing expression of a specific subset of NGF-sensitive genes, including Plaur, Mmp3, and/or Mmp10, required for neurite outgrowth. 相似文献
96.
Zhu D Mukherjee C Yang Y Rios BE Gallagher DT Smith NN Biehl ER Hua L 《Journal of biotechnology》2008,133(3):327-333
A nitrilase gene blr3397 from Bradyrhizobium japonicum USDA110 was cloned and over-expressed in Escherichia coli, and the encoded protein was purified to give a nitrilase with a single band of about 34.5kD on SDS-PAGE. The molecular weight of the holoenzyme was about 340kD as determined by light scattering analysis, suggesting that nitrilase blr3397 self-aggregated to an active form with the native structure being a decamer. The V(max) and K(m) for phenylacetonitrile were 3.15U/mg and 4.36mM, respectively. The catalytic constant k(cat) and specificity constant k(cat)/K(m) were 111min(-1) and 2.6x10(4)min(-1)M(-1). This nitrilase is most active toward the hydrolysis of hydrocinnamonitrile among the tested substrates (4.3 times that of phenylacetonitrile). The nitrilase blr3397 shows higher activity towards the hydrolysis of aliphatic nitriles than that for the aromatic counterparts, and can be characterized as an aliphatic nitrilase in terms of activity. This nitrilase also possesses distinct features from the nitrilase bll6402 of the same microbe. 相似文献
97.
Peterson RT Shaw SY Peterson TA Milan DJ Zhong TP Schreiber SL MacRae CA Fishman MC 《Nature biotechnology》2004,22(5):595-599
Conventional drug discovery approaches require a priori selection of an appropriate molecular target, but it is often not obvious which biological pathways must be targeted to reverse a disease phenotype. Phenotype-based screens offer the potential to identify pathways and potential therapies that influence disease processes. The zebrafish mutation gridlock (grl, affecting the gene hey2) disrupts aortic blood flow in a region and physiological manner akin to aortic coarctation in humans. Here we use a whole-organism, phenotype-based, small-molecule screen to discover a class of compounds that suppress the coarctation phenotype and permit survival to adulthood. These compounds function during the specification and migration of angioblasts. They act to upregulate expression of vascular endothelial growth factor (VEGF), and the activation of the VEGF pathway is sufficient to suppress the gridlock phenotype. Thus, organism-based screens allow the discovery of small molecules that ameliorate complex dysmorphic syndromes even without targeting the affected gene directly. 相似文献
98.
Proteomics of herpes simplex virus replication compartments: association of cellular DNA replication, repair, recombination, and chromatin remodeling proteins with ICP8 下载免费PDF全文
In this study, we have used immunoprecipitation and mass spectrometry to identify over 50 cellular and viral proteins that are associated with the herpes simplex virus 1 (HSV-1) ICP8 single-stranded DNA-binding protein. Many of the coprecipitating cellular proteins are known members of large cellular complexes involved in (i) DNA replication or damage repair, including RPA and MSH6; (ii) nonhomologous and homologous recombination, including the catalytic subunit of the DNA-dependent protein kinase, Ku86, and Rad50; and (iii) chromatin remodeling, including BRG1, BRM, hSNF2H, BAF155, mSin3a, and histone deacetylase 2. It appears that DNA mediates the association of certain proteins with ICP8, while more direct protein-protein interactions mediate the association with other proteins. A number of these proteins accumulate in viral replication compartments in the infected cell nucleus, indicating that these proteins may have a role in viral replication. WRN, which functions in cellular recombination pathways via its helicase and exonuclease activities, is not absolutely required for viral replication, as viral yields are only very slightly, if at all, decreased in WRN-deficient human primary fibroblasts compared to control cells. In Ku70-deficient murine embryonic fibroblasts, viral yields are increased by almost 50-fold, suggesting that the cellular nonhomologous end-joining pathway inhibits HSV replication. We hypothesize that some of the proteins coprecipitating with ICP8 are involved in HSV replication and may give new insight into viral replication mechanisms. 相似文献
99.
Timothy Reed Gerald H. Lushington Yan Xia Hidehiko Hirakawa DeAnna M. Travis Minae Mure Emily E. Scott Julian Limburg 《The Journal of biological chemistry》2010,285(33):25782-25791
Histamine dehydrogenase (HADH) isolated from Nocardioides simplex catalyzes the oxidative deamination of histamine to imidazole acetaldehyde. HADH is highly specific for histamine, and we are interested in understanding the recognition mode of histamine in its active site. We describe the first crystal structure of a recombinant form of HADH (HADH) to 2.7-Å resolution. HADH is a homodimer, where each 76-kDa subunit contains an iron-sulfur cluster ([4Fe-4S]2+) and a 6-S-cysteinyl flavin mononucleotide (6-S-Cys-FMN) as redox cofactors. The overall structure of HADH is very similar to that of trimethylamine dehydrogenase (TMADH) from Methylotrophus methylophilus (bacterium W3A1). However, some distinct differences between the structure of HADH and TMADH have been found. Tyr60, Trp264, and Trp355 provide the framework for the “aromatic bowl” that serves as a trimethylamine-binding site in TMADH is comprised of Gln65, Trp267, and Asp358, respectively, in HADH. The surface Tyr442 that is essential in transferring electrons to electron-transfer flavoprotein (ETF) in TMADH is not conserved in HADH. We use this structure to propose the binding mode for histamine in the active site of HADH through molecular modeling and to compare the interactions to those observed for other histamine-binding proteins whose structures are known. 相似文献
100.
Cholesterol and its hemisuccinate and sulfate derivatives are widely used in studies of purified membrane proteins but are difficult to solubilize in aqueous solution, even in the presence of detergent micelles. Other cholesterol derivatives do not form conventional micelles and lead to viscous solutions. To address these problems, a cholesterol-based detergent, CHOBIMALT, has been synthesized and characterized. At concentrations above 3?4 μM, CHOBIMALT forms micelles without the need for elevated temperatures or sonic disruption. Diffusion and fluorescence measurements indicated that CHOBIMALT micelles are large (210±30 kDa). The ability to solubilize a functional membrane protein was explored using a G-protein coupled receptor, the human kappa opioid receptor type 1 (hKOR1). While CHOBIMALT alone was not found to be effective as a surfactant for membrane extraction, when added to classical detergent micelles CHOBIMALT was observed to dramatically enhance the thermal stability of solubilized hKOR1. 相似文献