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991.
992.
Sustainable Coastal Development: The Dual Mandate and a Recommendation for "Commerce Managed Areas" 总被引:1,自引:0,他引:1
Pitting the dynamicism and uncertainty inherent in undisturbed coastal ecosystems against the stability and predictability required of human‐dominated landscapes creates the paradox of the dual mandate. We describe a gradient of estuarine types ranging from systems that experience little human intrusion—conservation estuaries—to those that are dominated by people or extractive uses—production and urban‐industrial estuaries. Future approaches to managing these estuarine resources will require a division of the concept of marine protected areas into at least two subcategories: “conservation” managed areas (CConservationMAs) and “commerce” managed areas (CCommerceMAs). The latter includes conditions where humans are not only a core feature of the landscape but also where extractive uses drive a large part of the local, regional, and even national economy. System reliability and predictability of ecosystem services are integral components of any management scheme in CCommerceMAs. By recognizing this division managers can construct appropriate baselines that encompass the biodiversity and ecological integrity inherent in relatively undisturbed estuaries (or portions thereof), or the ecosystem health and system reliability that characterize urban‐industrial systems. The terms ecosystem restoration and ecosystem rehabilitation are also distinguished; the former term is used to describe practices that return ecosystems to optimum biological integrity, whereas the latter term is applied to the health of human‐dominated estuaries where the goal is to manage natural processes and functions. Our proposed approach does not mean that ecosystem quality is sacrificed in urban‐industrial or production systems; to the contrary, contaminant source control, suitable sediment and water quality, and the human endeavors to address them are just as important to sustaining commercial activity as they are to the well‐being of extant biota. So too, are the conservation and preservation of existing critical habitat (proximate reservoirs of biodiversity) in urban‐industrial systems, and rehabilitation of habitats that support species coadapted to the presence of humans. 相似文献
993.
Calmodulin-specific monoclonal antibodies inhibit DNA replication in mammalian cells. 总被引:2,自引:0,他引:2
The involvement of calmodulin in the proliferation of Chinese hamster embryo fibroblast cells has been studied with a specific monoclonal antibody to calmodulin. We observed that calmodulin levels increase 2-fold in the late G1 period in these cells, and this coincides with the increase in DNA polymerase alpha activity as the cells progress synchronously from a quiescent state in the G1 to the S phase. However, there is a concurrent 10-fold enhancement of thymidine kinase activity, which is tightly coupled to the entry of cells into the S phase. Incubation of permeabilized S-phase cells with calmodulin-specific murine monoclonal antibody resulted in a dose-dependent inhibition of DNA replication. This inhibitory effect of anti-calmodulin antibodies on DNA replication is completely reversed by the addition of exogenously purified calmodulin. These observations provide evidence for the involvement of calmodulin in DNA replication and, therefore, in cell proliferation during the S phase. 相似文献
994.
Priscila L. dos Santos Fabrícia A. de Oliveira Micheli Luize B. Santos Luana Celina S. Cunha Michelle T. B. Lino Michelle F. S. de Oliveira Manuela O. M. Bomfim Angela Maria Silva Tatiana R. de Moura Amélia R. de Jesus Malcolm S. Duthie Steven G. Reed Roque P. de Almeida 《PLoS neglected tropical diseases》2016,10(1)
Background
Visceral leishmaniasis (VL) is a severe disease caused by infection with protozoa of the genus Leishmania. Classic VL is characterized by a systemic infection of phagocytic cells and an intense activation of the inflammatory response. It is unclear why 90% of infected individuals do not develop the disease while a minority develop the classical form. Furthermore, among those that develop disease, a small group progresses to more severe form that is unresponsive to treatment. The presence of inflammatory mediators in serum could theoretically help to control the infection. However, there is also a release of anti-inflammatory mediators that could interfere with the control of parasite multiplication. In this study, we took advantage of the spectrum of outcomes to test the hypothesis that the immune profile of individuals infected with Leishmania (L.) infantum is associated with the development and severity of disease.Methodology/Principal Findings
Sera from patients with confirmed diagnosis of VL were evaluated for the presence of numerous molecules, and levels compared with healthy control and asymptomatic infected individuals.Conclusions/Principal Findings
Although differences were not observed in LPS levels, higher levels of sCD14 were detected in VL patients. Our data suggest that L. infantum may activate the inflammatory response via CD14, stimulating a generalized inflammatory response with production of several cytokines and soluble molecules, including IFN-γ, IL-27, IL-10, IL-6 and sCD14. These molecules were strongly associated with hepatosplenomegaly, neutropenia and thrombocytopenia. We also observed that IL-6 levels greater than 200 pg/ml were strongly associated with death. Together our data reinforce the close relationship of IFN-γ, IL-10, IL-6, TNF-α and IL-27 in the immune dynamics of VL and suggest the direct participation of sCD14 in the activation of the immune response against L. infantum. 相似文献995.
Long-term effective population size is expected, and has been shown, to correlate positively with various measures of population
fitness. Here we examine the interacting effects of population size (as a surrogate for genetic factors) and prey consumption
rates (as a surrogate for environmental quality) on fecundity in two sympatric species of wolf spider, Rabidosa punctulata and Rabidosa rabida. Population size was estimated in each of seven genetically isolated populations in each of 3 years using mark-recapture
methods. Fecundity was estimated as the mean number of live offspring produced by ∼15 females sampled from each population
of each species each year for 3 years. Prey consumption rates were estimated by sampling ∼300 spiders per population per year
and assaying the proportion of spiders with prey. Larger populations have higher fecundity and more genetic diversity than
smaller populations. Variation among populations in fecundity for a given year could be attributed most strongly to differences
in population size, with variation in prey consumption rates and the interaction between population size and prey consumption
playing smaller but still important roles. During the most stressful environmental conditions, the smallest populations of
both species experienced disproportionately low-fecundity rates, more than doubling the estimated number of lethal equivalents
during those years. The evidence presented in this paper for inbreeding-environment interactions at the population level and
further evidence for a log-linear relationship between population size and fitness have important implications for conservation. 相似文献
996.
H. Fai Poon Laila Abdullah Jon Reed Sarah M. Doore Cyndi Laird Venkat Mathura Michael Mullan Fiona Crawford 《Biological procedures online》2007,9(1):65-72
Recent advances in redox proteomics have provided significant insight into the role of oxidative modifications in cellular
signalling and metabolism. At present, these techniques rely heavily on Western blots to visualize the oxidative modification
and corresponding two dimensional (2D) gels for detection of total protein levels, resulting in the duplication of efforts.
A major limitation associated with this methodology includes problematic matching up of gels and blots due to the differences
in processing and/or image acquisition. In this study, we present a new method which allows detection of protein oxidation
and total protein on the same gel to improve matching in image analysis. Furthermore, the digested protein spots are compatible
with standard MALDI mass spectrometry protein identification. The methodology highlighted here may be useful in facilitating
the development of biomarkers, assessing potential therapeutic targets and elucidating new mechanisms of redox signalling
in redox-related conditions. 相似文献
997.
Daniel C. Reed Bridget R. Deemer Sigrid van Grinsven John A. Harrison 《Biogeochemistry》2017,134(1-2):29-39
Collectively, freshwaters constitute a significant source of methane to the atmosphere, and both methane production and methane oxidation can strongly influence net emissions. Anaerobic methane oxidation (AOM) is recognized as a strong regulator of marine methane emissions and appreciation of AOM’s importance in freshwater is growing. In spite of this renewed interest, recent work and reactive-transport modeling results we present in this paper point to unresolved pathways for AOM. Comparison of recent observations from a eutrophic reservoir, Lacamas Lake, with predictions of a 1D steady-state model of water column methane dynamics indicates that high rates of methane oxidation measured via bottle assays cannot be explained with conventional electron acceptors (O2, NO2 ?, NO3 ?, SO4 2?, Mn4+, and Fe3+). Reactive-transport modeling suggests that solute oxidant concentrations at the thermocline would have to be around 10 times higher than observed to explain the measured methane consumption. Organic acids—a major constituent of organic matter—may account for part of this unexplained AOM given their abundance in eutrophic systems, although the details of these pathways remain elusive (e.g., which species are involved, seasonal renewal of reduced species, contribution of particulate versus dissolved phases). We point to several observations consistent with organic acid-mediated AOM, both in Lacamas Lake and in other systems. Nevertheless, direct evidence of this pathway is still lacking and testing for this remains an important direction for future work. To this end, we identify several new avenues of research that would help quantify the role of organic acid-mediated AOM relative to other electron acceptors. 相似文献
998.
DNA vaccination prevents and/or delays carcinoma development of papillomavirus-induced skin papillomas on rabbits 总被引:5,自引:0,他引:5 下载免费PDF全文
Han R Cladel NM Reed CA Peng X Budgeon LR Pickel M Christensen ND 《Journal of virology》2000,74(20):9712-9716
Malignant progression is a life-threatening consequence of human papillomavirus-associated lesions. In this study, we tested the efficacy of papillomavirus early-gene-based vaccines for prevention of carcinoma development of papillomavirus-induced skin papillomas on rabbits. Rabbit skin papillomas were initiated by infection with cottontail rabbit papillomavirus (CRPV). The papillomas were allowed to grow for 3 months without any treatment intervention. Rabbits were then immunized by gene gun-mediated intracutaneous administration of four DNA plasmids encoding CRPV E1, E2, E6, and E7 genes, respectively. All eight control rabbits receiving vector alone developed invasive carcinoma within 8 to 13 months. In contrast, only two of eight vaccinated rabbits developed carcinoma at 12 and 15 months, respectively. Papilloma growth was suppressed in the majority of vaccinated rabbits but not completely eradicated. These results indicate that gene gun-mediated immunization with papillomavirus early genes may be a promising strategy for prevention of malignant progression of human papillomavirus-associated lesions in humans. 相似文献
999.
Effect of chain unsaturation on the structure and thermotropic properties of galactocerebrosides. 下载免费PDF全文
Differential scanning calorimetry (DSC) and x-ray diffraction have been used to study the effect of increasing chain-unsaturation on the structure and properties of the hydrated cerebrosides N-stearoyl, -oleoyl, and -linoleoyl galactosylsphingosine (NSGS, NOGS, and NLnGS, respectively). DSC of hydrated (70 wt% water) NSGS shows an endothermic transition at 85 degrees C (delta H = 18.0 kcal/mol NSGS) and a broad exothermic transition at 40-60 degrees C, the latter being dependent upon the previous cooling rate. X-Ray diffraction patterns recorded at 21, 61, and 86 degrees C provide evidence for interconversions between metastable and stable crystalline NSGS bilayer phases. The properties of the unsaturated-chain cerebrosides are more complex. Hydrated NOGS shows a single endothermic transition at 44.8 degrees C (delta H = 11.5 kcal/mol NOGS). However, incubation of NOGS at 49 degrees C for 24 h results in a second transition at 55.5 degrees C. By cycling NOGS between 0 and 49 degrees C complete conversion into this higher melting phase (delta H = 12.1 kcal/mol NOGS) is achieved. X-ray diffraction confirms a bilayer phase at all temperatures and delineates the conversions between a crystalline phase at 21 degrees C (bilayer period d = 56.5A), a second crystalline phase at 47 degrees C (d = 69.9A), and a liquid crystalline phase at 59 degrees C (d = 52.0A). The more unsaturated NLnGS shows two transitions, a sharp transition at 28 degrees C (delta H = 8.0 kcal/mol NLGS) and a broad, low-enthalpy transition at 42 degrees C (delta H = 0.4 kcal/mol NLGS). Again, incubation between the two transitions leads to a single transition at 44 degrees C (delta H = 9.3 kcal/mol NLGS). X-ray diffraction demonstrates conversions between two crystalline bilayer phases (d = 55.2A and d = 68.4A), and a liquid crystalline bilayer phase (d = 51.8A). Thus, increased unsaturation in the amide-linked fatty acyl chain of cerebrosides results in decreased chain-melting temperatures (NSGS greater than NOGS greater than NLnGS) and has marked effects on their structural properties. 相似文献
1000.
An increase in nuclear DNA, without an increase in chromosome number, has been found to occur as a result of anther culture in Nicotiana tabacum L. The objective of this study was to determine the cytological consequences of this DNA amplification in F1 hybrids between a doubled haploid that had undergone a substantial increase in DNA and the cultivar from which that doubled haploid was derived. Mitotic and meiotic analyses were performed on plants obtained from reciprocal crosses of N. tabacum cv. NC95 and NC95 SCDHL 12, a doubled haploid line that has 41% more DNA than the parental cultivar. While no cytological abnormalities were observed in either parental line, numerous abnormalities were seen in both somatic and meiotic tissues of the F1 hybrid. Chromosome losses, which appeared to result from spindle errors, were observed in these tissues. It is speculated that the spindle errors may be the result of a genetic unbalance caused by combining genomes with widely differing amounts of DNA. In addition to the spindle errors, a quadrivalent with an atypical morphology was observed in meiotic diplotene and metaphase I cells of the hybrid. The quadrivalent configuration was interpreted to represent pairing between amplified homologous regions in homeologous chromosomes. Further investigations of additional doubled haploid × cultivar lines is required before the significance of these findings to the anther culture process in N. tabacum can be fully assessed. 相似文献