定向调控肠道微生物维护家禽肠道健康

定量PCR、基于PCR的DNA图谱技术、荧光原位杂交法、流式细胞术、新一代DNA测序和生物信息学分析等新技术被用于全面分析肠道微生物及其功能,而通过针对特定细菌调控肠道菌群是维持肠道健康进而提高家禽生产性能的有效策略。基于此,通过定向调控肠道微生物中的产气荚膜梭菌,研制出对家禽肠炎控制效果与抗生素接近的包被精油。     

Photochemical mass-independent sulfur isotopes in achondritic meteorites

Sulfides from four achondrite meteorite groups are enriched in 33S (up to 0.040 per mil) as compared with primitive chondrites and terrestrial standards. Stellar nucleosynthesis and cosmic ray spallation are ruled out as causes of the anomaly, but photochemical reactions in the early solar nebula could produce the isotopic composition. The large 33S excess present in oldhamite from the Norton County aubrite (0.161 per mil) suggests that refractory sulfide minerals condensed from a nebular gas with an enhanced carbon-oxygen ratio, but otherwise solar composition is the carrier. The presence of a mass-independent sulfur effect in meteorites argues for a similar process that could account for oxygen isotopic anomalies observed in refractory inclusions in primitive chondrites.     

Seismicity remotely triggered by the magnitude 7.3 landers, california, earthquake

The magnitude 7.3 Landers earthquake of 28 June 1992 triggered a remarkably sudden and widespread increase in earthquake activity across much of the western United States. The triggered earthquakes, which occurred at distances up to 1250 kilometers (17 source dimensions) from the Landers mainshock, were confined to areas of persistent seismicity and strike-slip to normal faulting. Many of the triggered areas also are sites of geothermal and recent volcanic activity. Static stress changes calculated for elastic models of the earthquake appear to be too small to have caused the triggering. The most promising explanations involve nonlinear interactions between large dynamic strains accompanying seismic waves from the mainshock and crustal fluids (perhaps including crustal magma).     

Can agroforestry improve soil fertility and carbon storage in smallholder banana farming systems?

Soil fertility depletion is a major constraint to agricultural production for smallholder farming households in many sub‐Saharan countries, and it is worsened by climate variability. In order to sustain food security for a growing population, measures have to be taken against C and nutrient losses from soils. This study examines whether banana–coffee agroforestry systems can improve soil fertility and C pools in smallholder farms in E Africa amidst observed climate variability. We selected 20 farms in Central Uganda, where soil samples were obtained from the top and subsoil layers. Samples were analyzed for several soil fertility parameters including soil organic matter (SOM), total soil organic C, pH, total N, plant‐available P, exchangeable K, texture, and bulk density. Soil C stocks were calculated based on soil organic C concentrations and bulky density. We measured tree diameter and height and calculated aboveground plant biomass using allometric equations. Belowground biomass was estimated using equations based on the respective aboveground plant biomass. Our results show that banana–coffee agroforestry farming systems had significantly higher total SOM and total N compared to the banana monoculture. Similar trends were observed for soil C stocks and total C pools. The former contained 1.5 times higher soil C stocks than the latter. Likewise, the mean total C pools for the banana–coffee agroforestry farm plots were 26% larger than that under banana monoculture. However, exchangeable K was higher in the soil of banana monocultures. Plant‐available P levels were limiting under both farming systems. The study demonstrates that beyond socio‐economic benefits banana–coffee agroforestry farming systems have beneficial effects on soil fertility and C sequestration compared to banana monocultures in the study area. However, precautions to avoid P depletion have to be taken under current climate conditions.     

Imaging genome abnormalities in cancer research

Increasing attention is focusing on chromosomal and genome structure in cancer research due to the fact that genomic instability plays a principal role in cancer initiation, progression and response to chemotherapeutic agents. The integrity of the genome (including structural, behavioral and functional aspects) of normal and cancer cells can be monitored with direct visualization by using a variety of cutting edge molecular cytogenetic technologies that are now available in the field of cancer research. Examples are presented in this review by grouping these methodologies into four categories visualizing different yet closely related major levels of genome structures. An integrated discussion is also presented on several ongoing projects involving the illustration of mitotic and meiotic chromatin loops; the identification of defective mitotic figures (DMF), a new type of chromosomal aberration capable of monitoring condensation defects in cancer; the establishment of a method that uses Non-Clonal Chromosomal Aberrations (NCCAs) as an index to monitor genomic instability; and the characterization of apoptosis related chromosomal fragmentations caused by drug treatments.     

Tocotrienol and fatty acid composition of barley oil and their effects on lipid metabolism

Barley oil was extracted with hexane from the grain of a high oil waxy hull-les barley. Twelve male broiler chicks were fed corn-based diets with either 10% barley oil, 10% corn oil or 10% margarinead libitum for ten days. Total plasma cholesterol concentration of the chicks fed barley oil was 34% lower (p<0.05) than that of the chicks fed margarine. Plasma low density lipoprotein cholesterol concentration of chicks fed barley oil was 53% and 59% lower (p<0.05) than those of chicks fed corn oil and margarine, respectively. Plasma high density lipoprotein cholesterol and triglyceride concentration of the barley oil group were similar to those of the margarine but higher (p<0.05) than those of the corn oil group. Chicks fed the barley oil gained more (p<0.05) body weight than those fed the corn oil and margarine. Barley oil had an effect in suppression of TC and LDLC in chicks compared to margarine. Barley oil supressed LDLC but not HDLC in chicks compared to corn oil. A greater weight gain of the chicks fed barley oil suggested that these chicks had normally functioning digestion and absorption. -Tocotrienol and -tocotrienol content of the barley oil were 24 and 17 times greater, respectively, than those observed in the corn oil, while the same fractions were not detectable in the margarine. Polyunsaturated fatty acid content of the barley oil was more than threefold that of margarine. These data suggest that -tocotrienol and polyunsaturated fatty acids are hypocholesterolemic components in barley oil.Contribution No. J-2617, Montana Agricultural Experiment Station. This research was supported, in part, by grants from the Montana Wheat and Barley Committee, Great Falls, MT and Ross Laboratories, Columbus, OH.