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61.
Birgit Dittrich 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(4):441-449
Summary
Hyperia galba was collected in the waters around Helgoland and in the Weser-Elbe-estuary during autumn. Its mode of life is a temporary but obligatory parasitism. The basal biochemical composition of the adults was analyzed in detail and related to the fresh, dry, and ash-free dry weight as well as sex and body length. Hyperia galba (males/females) consists of 85/86% water; the dry matter contains approximately 64/61% protein, 10/11% lipid, 1.2/1.5% carbohydrate, 10/8% chitin, and 23/23% ash. The analyses of basal elemental composition yielded approximately 38% C, 9% N and 6% H. Under natural conditions, individuals may encounter at least two periods of food shortage during their lives. Therefore, the analyses were carried out on individuals of different developmental stages also under food deprivation. The data are discussed with respect to the special mode of life of the species and compared with those found by other authors in several related crustacean species.Abbreviations
AFDW
ash-free dry weight
-
BL
body length
-
DW
dry weight
-
SD
standard deviation
-
WW
wet weight 相似文献
62.
Photons are widely used in radiotherapy and while they are low LET radiation, can still pose a risk in developing second malignant neoplasms (SMN). Due to the physics of photons that allow distribution of energy outside the target volume, out-of-field irradiation is an important component of SMN risk assessment. The epidemiological evidence supporting this risk should be augmented with radiobiological justifications for a better understanding of the underlying processes.There are several factors that impact second cancer risk which can be analysed from a radiobiological perspective: age at irradiation, type of irradiated tissue, irradiated volume, treatment technique, previous irradiation/radiological investigations. Age-dependence has a radiobiological foundation given by the higher radiosensitivity of children as compared to adult patients. However, in its 2013 report, UNSCEAR advises against generalisation of the effects of childhood radiation exposure, given the fact that these effects are strongly organ dependent. Furthermore, the age-dependent radiation sensitivity has a bimodal distribution, since aging cells present an increase in the oxidative stress, which can promote premalignant cells.Non-targeted effects such as radiation-induced genomic instability, bystander or abscopal effects could also impact on the risk of SMN. Recent studies show that beside the known cellular changes, bystander effects can be manifested through increased cell proliferation, which could be a culprit for SMN development. Furthermore, new evidence on the existence of tumour-specific cancer stem cells that are long-lived and more quiescent and radioresistant than non-stem cancer cells can raise questions about their association with SMN risk. 相似文献
63.
Jean‐Paul A. Hobbs Geoffrey P. Jones Philip L. Munday Sean R. Connolly Maya Srinivasan 《Journal of Biogeography》2012,39(1):130-139
Aim To determine the applicability of biogeographical and ecological theory to marine species at two remote island locations. This study examines how biogeography, isolation and species geographic range size influence patterns of species richness, endemism, species composition and the abundance of coral reef fishes. Location Christmas Island and the Cocos (Keeling) Islands in the tropical eastern Indian Ocean. Methods Published species lists and underwater visual surveys were used to determine species richness, endemism, species composition and abundance of reef fishes at the islands. These data were statistically compared with patterns of species composition and abundance from the neighbouring ‘mainland’ Indonesian region. Results The two isolated reef fish communities were species‐poor and contained a distinct taxonomic composition with an overrepresentation of species with high dispersal potential. Despite low species richness, we found no evidence of density compensation, with population densities on the islands similar to those of species‐rich mainland assemblages. The mix of Indian and Pacific Ocean species and the proportional representations of the various regional faunas in the assemblages were not influenced by the relative proximity of the islands to different biogeographical provinces. Moreover, species at the edge of their range did not have a lower abundance than species at the centre of their range, and endemic species had substantially higher abundances than widespread species. At both locations, endemism was low (less than 1.2% of the community); this may be because the locations are not sufficiently isolated or old enough to promote the evolution of endemic species. Main conclusions The patterns observed generally conform to terrestrial biogeographical theory, suggesting that similar processes may be influencing species richness and community composition in reef fish communities at these remote islands. However, species abundances differed from typical terrestrial patterns, and this may be because of the life history of reef fishes and the processes maintaining isolated populations. 相似文献
64.
Parker Crutchfield 《Bioethics》2020,34(2):190-194
In a recent issue of Bioethics, I argued that compulsory moral bioenhancement should be administered covertly. Alexander Zambrano has criticized this argument on two fronts. First, contrary to my claim, Zambrano claims that the prevention of ultimate harm by covert moral bioenhancement fails to meet conditions for permissible liberty-restricting public health interventions. Second, contrary to my claim, Zambrano claims that covert moral bioenhancement undermines autonomy to a greater degree than does overt moral bioenhancement. In this paper, I rebut both of these arguments, then finish by noting important avenues of research that Zambrano’s arguments motivate. 相似文献
65.
Monte Carlo simulations and a modified Poisson–Boltzmann (MPB) theory are used to investigate the temperature dependence of the capacitance (around the potential of zero charge) of an electric double layer in the presence of surface polarization due to a dielectric boundary. Within the context of the restricted primitive model planar double layer, whose solvent dielectric constant is ε2, the cases when the electrode is an insulator (ε1 = 1), when the electrode and the electrolyte have the same permittivity (ε1 = ε2, no polarization), and when the electrode is a conductor (ε1 → ∞) are studied for the case where the electrolyte concentration is 0.1 M. The simulations reveal a capacitance anomaly, that is, a positive temperature dependence of the capacitance at low temperatures for the former two situations. The MPB theory also shows this effect for these two situations and is in qualitative or better agreement with the simulation data. In these two cases, both the simulations and theory show a dramatic increase of the diffuse layer potential in the temperature regime where capacitance anomaly occurs. However, in the latter situation, where the electrode is metallic, the capacitance always has a negative temperature derivative for the MPB theory and probably also for the simulation data. 相似文献
66.
Wenjuan Ding Fangfang Wang Qingwen Li Yaxin Xue Zhitong Dong Danmei Tian Mei Chen Youwei Zhang Kui Hong Jinshan Tang 《化学与生物多样性》2021,18(7):e2100229
Marine derived fungus has gained increasing ground in the discovery of novel lead compounds with potent biological activities including anti-inflammation. Here, we first report the characterization of one new sorbicillinoid ( 1 ) and fourteen known compounds ( 2 – 15 ) from the ethyl acetate (AcOEt) extract of a cultured mangrove derived fungus Penicillium sp. DM815 by UV, IR, HR ESI-Q-TOF MS, and NMR spectra. We then evaluated the anti-inflammatory effects of eleven sorbicillinoids ( 1 – 11 ) using cultured macrophage RAW264.7 cells. The results show that compound 9 , and to a lesser degree compound 5 , significantly inhibited the Gram-negative bacteria lipopolysaccharide (LPS)-induced upregulation of the inducible nitric oxide synthase (iNOS). Consistently, compounds 5 and 9 significantly reduced the level of nitric oxide (NO), the product of iNOS, induced by LPS. We further show that these two compounds dose-dependently inhibited LPS-triggered iNOS expression and NO production, but had no effect on proliferation of RAW264.7 cells in the presence of LPS. In conclusion, our study identifies novel and known sorbicillinoids as potent anti-inflammatory agents, holding the promise of developing novel anti-inflammation treatment in the future. 相似文献
67.
68.
《Journal of biological dynamics》2013,7(4):409-427
We propose a discrete-time, age-structured population model to study the impact of Allee effects and harvesting. It is assumed that survival probabilities from one age class to the next are constants and fertility rate is a function of weighted total population size. Global extinction is certain if the maximal growth rate of the population is less than one. The model can have multiple attractors and the asymptotic dynamics of the population depend on its initial distribution if the maximal growth rate is larger than one. An Allee threshold depending on the components of the unstable interior equilibrium is derived when only the last age class can reproduce. The population becomes extinct if its initial population distribution is below the threshold. Harvesting on any particular age class can decrease the magnitude of the possible stable interior equilibrium and increase the magnitude of the unstable interior equilibrium simultaneously. 相似文献
69.
Three new geranylated flavonoids, including two geranylflavones (1, 2) and one geranylflavonol (3), named as paucatalinone C–E, were isolated from the fruit peel of P. catalpifolia T. Gong ex D.Y. Hong. Their structures were determined by means of UV, IR, MS, and NMR techniques. To our known, geranylflavone or geranylflavonol was the first isolation from the genus Paulownia. These isolated geranylated flavonoids displayed good antioxidant effects on DPPH and the senescent human embryonic lung diploid fibroblasts cells (2BS cells) induced by H2O2. The geranyl substituent may be an important factor for the cellular radical-scavenging effect because of its lipophilic character. 相似文献
70.