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101.
Louis Cara Patrick Borel Martine Armand Michele Senft Huguette Lafont Henri Portugal Anne-Marie Pauli Daniele Boulze Christianne Lacombe Denis Lairon 《Plant foods for human nutrition (Dordrecht, Netherlands)》1991,41(2):135-150
The present study was performed to investigate the possible effects of wheat germ supplementation on lipid metabolism in humans. Ten free-living adult subjects participated in the study. None was obese or diabetic. They all presented an, hypercholesterolemia (from 6.58 to 9.50 mM), associated in 6 over 10 cases to an hypertriglyceridemia (from 1.70 to 5.00 mM). The subjects were studied in three consecutive periods, during which they first were on their usual diet (first week), they then ingested a daily supplement of 30 g wheat germ (4 weeks) and then they returned to their usual basal diet (4 weeks follow-up). Dietary records were obtained for 7 and 3 consecutive days before and during wheat germ supplementation, respectively. Fasting blood samples were taken at the end of each period. After 4 weeks of wheat, germ intake, glycemia did not change while total plasma cholesterol significantly decreased (paired Student'st test,p0.05) from 7.80 to 7.15 mM. LDL and HDL cholesterol values did not show marked changes, but VLDL cholesterol significantly dropped by 40.6%. Thus, the plasma/HDL total cholesterol ratio was significantly lower. Apoprotein B and A1 decreased. In the hypertriglyceridemic subjects, this was accompanied by a significant reduction of plasma triglycerides (1.64 vs. 2.68 mM) and a marked drop of VLDL triglycerides (–51%). Taken as a whole, the present results obtained in humans are very close to those previously obtained in the rat [40] and point out that wheat germ may play a beneficial role in the dietary management of hyperlipidemia.Part of the data communicated in this paper was presented at the Fibre 90 Conference, 17–20 April 1990, Norwich, UK. 相似文献
102.
Background : Rice production in low‐input systems of West Africa relies largely on nitrogen supply from the soil. Especially in the dry savanna agro‐ecological zone, soil organic N is mineralized during the transition period between the dry and the wet seasons. In addition, in the inland valley landscape, soil N that is mineralized on slopes may be translocated as nitrate into the lowlands. There, both in‐situ mineralized as well as the laterally translocated nitrate‐N will be exposed to anaerobic conditions and is thus prone to losses. Aim : We determined the dynamics of soil NO3‐N along a valley toposequence during the dry‐to‐wet season transition period and the effects of soil N‐conserving production strategies on the grain yield of rainfed lowland rice grown during the subsequent wet season. Methods : Field experiments in Dano (Burkina Faso) assessed during two consecutive years the temporal dynamics and spatial fluxes of soil nitrate along a toposequence. We applied sequential and depth‐stratified soil nitrate analysis and nitrate absorption in ion exchange resin capsules in lowlands that were open to subsurface interflow and in those where the interflow from the was intercepted. During one year only we also assessed the effect of pre‐rice vegetation on conserving this NO3‐N as well as on N addition by biological N2 fixation in legumes using δ15N isotope dilution. Finally, we determined the impact of soil N fluxes and their differential management during the transition season on growth, yield and N use of rainfed lowland rice. Results : Following the first rainfall event of the season, soil NO3‐N initially accumulated and subsequently decreased gradually in the soil of the valley slope. Much of this nitrate N was translocated by lateral sub‐surface flow into the valley bottom wetland. There, pre‐rice vegetation was able to absorb much of the in‐situ mineralized and the laterally‐translocated soil NO3‐N, reducing its accumulation in the soil from 40–43 kg N ha?1 under a bare fallow to 1–23 kg N ha?1 in soils covered by vegetation. Nitrogen accumulation in the biomass of the transition season crops ranged from 44 to 79 kg N ha?1 with a 36–39% contribution from biological N2 fixation in the case of legumes. Rice agronomic performance improved following the incorporation as green manure of this “nitrate catching” vegetation, with yields increasing up to 3.5 t ha?1 with N2‐fixing transition seasons crops. Conclusion : Thus, integrating transition season legumes during the pre‐rice cropping niche in the prevailing low‐input systems in inland valleys of the dry savanna zone of West Africa can temporarily conserve substantial amounts of soil NO3‐N. It can also add biologically‐fixed N, thus contributing to increase rice yields in the short‐term and, in the long‐term, possibly maintaining or improving soil fertility in the lowland. 相似文献
103.
Papuamide A is representative of a class of marine derived cyclic depsipeptides, reported to have cytoprotective activity against HIV-1 in vitro. We show here that papuamide A acts as an entry inhibitor, preventing human immunodeficiency virus infection of host cells and that this inhibition is not specific to R5 or X4 tropic virus. This inhibition of viral entry was determined to not be due to papuamide A binding to CD4 or HIV gp120, the two proteins involved in the cell-virus recognition and binding. Furthermore, papuamide A was able to inhibit HIV pseudotype viruses expressing envelope glycoproteins from vesicular stomatitis virus or amphotropic murine leukemia virus indicating the mechanism of viral entry inhibition is not HIV-1 envelope glycoprotein specific. Time delayed addition studies with the pseudotyped viruses show that papuamide A inhibits viral infection only at the initial stage of the viral life cycle. Additionally, pretreatment studies revealed that the virus, and not the cell, is the target of papuamide A’s action. Together, these results suggest a direct virucidal mechanism of HIV-1 inhibition by papuamide A. We also demonstrate here that the other papuamides (B-D) are able to inhibit viral entry indicating that the free amino moiety of 2,3-diaminobutanoic acid residue is not required for the virucidal activity. 相似文献
104.
The elongated encased spermatophores of the capsalid (entobdelline) monogeneans Neoentobdella diadema (Monticelli, 1902) Kearn et Whittington, 2005 and N. apiocolpos (Euzet et Maillard, 1967) Kearn et Whittington, 2005 have been found attached by their proximal ends to the region of the vaginal opening, with the bulk of the spermatophore projecting from the vagina and therefore lying outside the body. In spite of previous reports, no spermatophores were found projecting from the common genital opening and if spermatophore exchange is as rapid as it is in the related entobdelline Entobdella soleae, then the chances of finding a spermatophore in this location are small. In N. diadema and N. apiocolpos it is likely that sperm enters the vagina through the open proximal end of an attached spermatophore, after which the empty spermatophore case is probably discarded. There is no evidence for a previous proposal that the whole spermatophore is engulfed by the vagina followed by digestion of the case to release the sperm. Three specimens of N. diadema were found each with two spermatophore cases projecting from the vagina and a specimen of N. apiocolpos carried three cases. Assuming that each parasite is able to donate or receive only one spermatophore at each mating, then the presence of one spermatophore does not prevent a further mating and acceptance of a fresh spermatophore. In spite of differences between the spermatophores of E. soleae and N. diadema/N. apiocolpos, the events of spermatophore exchange may be similar. 相似文献
105.
106.
Marine Ollier Vincent Talle Anne‐Laure Brisset Zo Le Bihan Simon Duerr Marc Lemmens Ellen Goudemand Olivier Robert Jean‐Louis Hilbert Hermann Buerstmayr 《Plant Breeding》2019,138(1):69-81
Fusarium head blight (FHB) is a cereal disease of major importance responsible for yield losses and mycotoxin contaminations in grains. Here, we introduce a new measurement approach to quantify FHB severity on grains based on the evaluation of the whitened kernel surface (WKS) using digital image analysis. The applicability of WKS was assessed on two bread wheat and one triticale grain sample sets (265 samples). Pearson correlation coefficients between Fusarium‐damaged kernels (FDK) and WKS range from r = 0.77 to r = 0.81 and from r = 0.61 to r = 0.86 for the correlation between deoxynivalenol (DON) content and WKS. This new scoring method facilitates fast and reliable assessment of the resistance to kernel infection and shows significant correlation with mycotoxin content. WKS can be automated and does not suffer from the “human factor” inherent to visual scorings. As a low‐cost and fast approach, this method appears particularly attractive for breeding and genetic analysis of FHB resistance where typically large numbers of experimental lines need to be evaluated, and for which WKS is suggested as an alternative to visual FDK scorings. 相似文献
107.
Logging pattern and landscape changes over the last century at the boreal and deciduous forest transition in Eastern Canada 总被引:4,自引:0,他引:4
Forestry practices associated with the industrial era (since ~1900) have altered the natural disturbance regimes and greatly
impacted the world’s forests. We quantified twentieth century logging patterns and regional scale consequences in three sub-boreal
forest landscapes of Eastern Canada (117,000, 49,400 and 92,300 ha), comparing forestry maps depicting age and forest cover
types for early industrial (1930) and present-day (2000) conditions. Results were similar for the three landscapes, indicating
large-scale forest change during the twentieth century. In 1930, previous logging activities had been concentrated in the
lowlands and along the main hydrographical network, as compared to a more even distribution over the landscapes in 2000, reflecting
a decreasing influence of the environmental constraints on forest harvesting. In 1930, old-aged forests (>100 years) accounted
for more than 75% of the unlogged areas of the three landscapes, as compared to less than 15% for the present-day conditions.
Logging practices have thus inverted the stand age distribution of the landscapes that are currently dominated by young and
regenerating stands. The 1930 forest cover types showed a clear relationship with elevation, with conifers located in the
lowlands and mixed and deciduous stands restricted to the upper slopes. Between 1930 and 2000, 58–64% of the conifer areas
transformed to mixed and deciduous forests, such that no clear altitudinal relationships remained in 2000. We conclude that
twentieth century logging practices have strongly altered the preindustrial vegetation patterns in our study area, to the
point that ecosystem-based management strategies should be developed to restore conifer dominance, altitudinal gradients,
as well as the irregular structure inspired from old forest stands. 相似文献
108.
Effects of landscape structure on nest predation in roadsides of a midwestern agroecosystem: a multiscale analysis 总被引:1,自引:1,他引:0
Bergin Timothy M. Best Louis B. Freemark Kathryn E. Koehler Kenneth J. 《Landscape Ecology》2000,15(2):131-143
Nest predation is an important cause of mortality for many bird species, especially in grassland ecosystems where generalist predators have responded positively to human disturbance and landscape fragmentation. Our study evaluated the influence of the composition and configuration of the surrounding landscape on nest predation. Transects consisting of 10 artificial ground nests each were set up in 136 roadsides in six watersheds in south-central Iowa. Nest predation on individual roadside transects ranged from 0 to 100% and averaged 23%. The relationship of landscape structure within spatially-nested landscapes surrounding each roadside transect (within 200, 400, 800, 1200, and 1600 m of the transect line) to nest predation was evaluated by using multiple regression and canonical correlation analyses. The results of this multiscale landscape analysis demonstrated that predation on ground nests was affected by the surrounding landscape mosaic and that nest predators with different-sized home ranges and habitat affinities responded to landscapes in different ways. In general, wooded habitats were associated with greater nest predation, whereas herbaceous habitats (except alfalfa/pasture) either were associated with less nest predation or were not important. Different landscape variables were important at different spatial scales. Whereas some block-cover habitats such as woodland were important at all scales, others such as rowcrops and alfalfa/pasture were important at large scales. Some strip-cover habitats such as gravel roads and paved roads were important at small scales, but others such as wooded roadsides were important at all all scales. Most landscape metrics (e.g., mean patch size and edge density) were important at large scales. Our study demonstrated that the relationships between landscape structure and predator assemblages are complex, thus making efforts to enhance avian productivity in agricultural landscapes a difficult management goal. 相似文献
109.
110.
Louis R. Iverson Frank R. ThompsonIII Stephen Matthews Matthew Peters Anantha Prasad William D. Dijak Jacob Fraser Wen J. Wang Brice Hanberry Hong He Maria Janowiak Patricia Butler Leslie Brandt Christopher Swanston 《Landscape Ecology》2017,32(7):1327-1346