A 100,000-year periodicity in the accretion rate of interplanetary dust

Numerical modeling of the orbital evolution of interplanetary dust particles revealed that, over the past 1.2 million years, the rate of accretion of dust by Earth has varied by a factor of 2 to 3. These variations display a 100,000-year periodicity and are anticorrelated with Earth's changing orbital eccentricity. Extraterrestrial helium-3 concentrations in a deep-sea sediment core display a similar periodicity but are 50,000 years out of phase with the predicted variations. Also, because collisions between large bodies in the asteroid belt are inevitable, it is expected that large-amplitude stochastic variations on 10(7)- to 10(8)-year time scales would be superimposed on the 10(5)-year periodic variations.     

Assessment of prebiotic potentials in selected leaf meals of high dietary fibre on growth performance,body composition,nutrient utilization and amylase activities of a tropical commercial carp fingerlings

The performance of selected leaf meals of high dietary fibre in the feed of a tropical commercial carp, hybrid lemon fin barb (Barbonymus gonionotus ♀ × Hypsibarbus wetmorei ♂) was evaluated in a 56‐day feeding trial. The tropical carp juveniles (9.43 ± 0.05 g) were randomly stocked in 60‐L aquaria at 15 fish per aquarium. Five isonitrogenous and isocaloric diets (30% crude protein, 17 kJ/g gross energy) containing no leaf meal and 10% napier grass (Pennisetum purpureum), alfalfa (Medicago sativa), water spinach (Ipomea aquatica) and Gliricidia sepium leaf meals were formulated and tested. Three aquaria were randomly assigned to each experimental diet. The results showed that fish‐fed diets containing leaf meals showed superior growth performance and body composition which was better than those fed control diet. The leaf meal‐treated groups also had higher values of protein, lipid, energy retention and production of digestive enzymes amylase. Conclusively, the results indicated that leaf meal fibre provided better performance showing the inherent prebiotic effect of the utilization of these leaf meal in hybrid lemon fin barb .     

Comparative Study on Growth Performance of Transgenic(Over-Expressed OsNHX1) and Wild-Type Nipponbare under Different Salinity Regimes

Transgenic Nipponbare which over-expressed a Na+/H+ antiporter gene OsNHX1 was used to compare its growth performance, water status and photosynthetic efficiency with its wild type under varying salinity regimes. Chlorophyll content, quantum yield and photosynthetic rate were measured to assess the impact of salinity stress on photosynthetic efficiency for transgenic and wild-type Nipponbare. Effects of salinity on water status and gas exchange to both lines were studied by measuring water use efficiency, instantaneous transpiration rate and stomatal conductance. Dry shoot weight and leaf area were determined after three months of growth to assess the impacts of salinity on the growth of those two lines. Our study showed that both lines were affected by salinity stress, however, the transgenic line showed higher photosynthetic efficiency, better utilization of water, and better growth due to low transpiration rate and stomatal conductance. Reduction of photosynthetic efficiency exhibited by the wild-type Nipponbare was correlated to its poor growth under salinity stress.     

Subereamolline A as a Potent Breast Cancer Migration, Invasion and Proliferation Inhibitor and Bioactive Dibrominated Alkaloids from the Red Sea Sponge Pseudoceratina arabica

A new collection of several Red Sea sponges was investigated for the discovery of potential breast cancer migration inhibitors. Extracts of the Verongid sponges Pseudoceratina arabica and Suberea mollis were selected. Bioassay-directed fractionation of both sponges, using the wound-healing assay, resulted into the isolation of several new and known brominated alkaloids. Active fractions of the sponge Pseudoceratina arabica afforded five new alkaloids, ceratinines A–E (2–6), together with the known alkaloids moloka’iamine (1), hydroxymoloka’iamine (7) and moloka’iakitamide (8). The active fraction of the sponge Suberea mollis afforded the three known alkaloids subereamolline A (9), aerothionin (10) and homoaerothionin (11). Ceratinine B (3) possesses an unprecedented 5,7-dibrominated dihydroindole moiety with an epoxy ring on the side chain of a fully substituted aromatic moiety. Ceratinines D (5) and E (6) possess a terminal formamide moiety at the ethylamine side chain. Subereamolline A (9) potently inhibited the migration and invasion of the highly metastatic human breast cancer cells MDA-MB-231 at the nanomolar doses. Subereamolline A and related brominated alkaloids are novel scaffolds appropriate for further future use for the control of metastatic breast cancer.     

Analysis of DNA Methylation and mRNA Expression Level of MSTN Gene in Xinjiang Bashiby Sheep

In order to investigate DNA methylation and expression levels of myostatin (MSTN) gene in mscule and fat, 5 months of age of Bashiby sheep were selected, the promoter region and exon 1 methylation levels of MSTN gene was analyzed using bisulfite sequencing PCR (BSP). Real-time PCR was used to detect the expression level of MSTN gene in biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle and tail fat of Bashiby sheep. The results showed that the methylation probability of muscle was higher than fat, the methylation probability of biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle and tail fat were 74.2%, 74.2%, 83.2%, 83.7%, 82.1% and 25.3%, respectively. The expression levels of MSTN gene in biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle were significantly lower than tail fat in Bashiby sheep (P < 0.05), but there were no significant difference among biceps femoris, femoral triceps, semitendinosus, semimembranosus and longissimus dorsi muscle (P > 0.05).The DNA methylation was negatively correlated with the expression levels in muscle and fat of Bashiby sheep (r=-0.886, P < 0.05).     

Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

Summary Two German cultivars differing in blackspot susceptibility were grown in pots in 1998 and 1999 under control and water stress conditions. Blackspot susceptibility of the tubers was defined as oxidative potential. The effect of free tyrosine, cysteine, phenylalanine, chlorogenic and ascorbic acid on the oxidative potential was analyzed. A high concentration of ascorbic acid led to a decrease in the oxidative potential after harvesting in 1998. No correlation was found between oxidative potential and free tyrosine, phenylalanine or cysteine, respectively. Chlorogenic acid content increased during storage and gave a significant correlation with discoloration, showing that it can have an effect on the oxidative potential of the tuber greater than previously thought. Supplementing freeze-dried potato samples with pure chlorogenic acid increased the oxidative potential. Oxidative potential seems to depend on a series of chemical compounds, and their content is affected by factors including annual variations, cultivar, water availability and storage.     

Molecular and morphological characterization of stunt nematodes of wheat,maize, and rice in the savannahs of northern Nigeria

Stunt nematodes(Tylenchorhynchus spp.) are obligate migratory root ecto-parasitic nematodes found in the fields of many cultivated crops. These nematodes, with phyto-sanitary potential, are frequently ignored or misdiagnosed as pests, and this may pose a threat to food security. The accuracy of its identification based on a morphological approach has been challenged recently, due to the overlapping of the morphological and morphometric characters of the species. Consequently, the objective of th...     

Different Months of MSTN Gene mRNA Expression Levels and their Correlation with Growth Traits in Five Xinjiang Local Sheep

To explore the different varieties of five Xinjiang local sheep myostatin (MSTN) expression levels and their correlation with growth traits (body weight,body height,body length,heart girth and cannon circumference).The MSTN mRNA expression level in different month(Birth,1 months,2 months,3 months,4 months,5 months) of muscle and fat in Altay sheep,Turpan Black sheep,Emil White sheep,Kazakh sheep,Bashbay sheep by quantitative Real-time PCR method,using SPSS 19.0 software to analyze the correlation with growth traits.The MSTN mRNA expression levels in muscle:The MSTN gene mRNA expression levels of Altay sheep,Kazakh sheep and Bashbay sheep at birth were lower than other months;The MSTN gene mRNA expression level of Emil White sheep in 3 months was significantly lower than other months (P<0.05);The MSTN gene mRNA expression levels of Altay sheep,Turpan Black sheep were the highest in 4 months;The MSTN gene mRNA expression level of Kazakh sheep was the lowest at birth,and was the highest in 5 months.The MSTN gene mRNA expression levels in fat:The MSTN gene mRNA expression level of Emil White sheep at birth was significantly lower than other months (P<0.05); The MSTN gene mRNA expression levels of Altay sheep,Emil White sheep and Bashbay sheep were the highest in 5 months,the MSTN gene mRNA expression level of Bashbay sheep in 5 months was significantly higher than other months (P<0.05);The MSTN gene mRNA expression level of Kazakh sheep was the highest in 2 month,it was significantly higher than 5 months (P<0.05).Correlation analysis revealed that the MSTN gene mRNA expression levels were mostly negatively correlated with growth traits.The MSTN gene mRNA expression levels in muscle and fat of Altay sheep were all negatively correlated with growth traits;The MSTN gene mRNA expression levels in muscle of Turpan Black sheep were negative correlated with body length and body height,others were positively;The MSTN gene mRNA expression levels in muscle of Emil White sheep were positive correlated with heart girth and cannon circumference;The MSTN gene mRNA expression levels in fat were positive correlated with body length,others were negatively correlation;The MSTN gene mRNA expression levels in muscle and fat of Kazakh sheep were positive correlated with body length,others were negatively correlation;The MSTN gene mRNA expression levels in muscle of Bashbay sheep were positive correlated with body length and cannon circumference,others were negatively correlation.The MSTN gene mRNA expression level was discrepancy in different month of different varieties,and was no fixed expression pattern;The MSTN gene mRNA expression levels were positively correlated with the part of the body size.The MSTN gene mRNA expression levels might have a direct relationship with the growth traits and bone growth.     

和田绿洲土地沙化及其防治措施

和田地区由于自然地理环境及人类活动的不良影响，风沙灾害严重，大量绿洲被沙漠吞噬。农业生态条件日益恶化，已危及了国民经济的发展。在保持生态平衡的前提下，通过对河流进行全面治理，恢复植被，防风固沙。保存和繁荣和田绿洲已成为当务之急。     

An assessment of the drought tolerance of Fraxinus genotypes for urban landscape plantings

The Fraxinus genus consists of ca. 65 deciduous, rarely evergreen trees found mainly throughout Europe, Asia and North America. Fraxinus species possess the aesthetic characteristics desired of urban trees (autumn colour, attractive bark and flowers); however, no scientifically based tolerance ranking exists for many genotypes within this genera. Aims of this study were to identify whether differences in drought tolerance exist within the Fraxinus genus and thereby provide information as to their usefulness for planting in urban landscapes where water stress poses a threat to transplant survival. At the cessation of a 2-week drought stress and subsequent recovery period, marked differences in drought tolerance among genotypes were distinguished based on net photosynthesis, leaf chlorophyll fluorescence and chlorophyll concentration. In addition, measurement of light absorbance, light trapping, electron transport and dissipation fluxes per leaf cross section of photosystem II at the cessation of the drought period provided an insight into mechanisms of drought damage and resilience among the genotypes tested. The results of this investigation indicate that F. excelsior ‘Aurea Pendula’, F. nigra Marsh., F. ornus L., F. angustifolia ‘Raywood’, F. excelsior L. and F. excelsior ‘Jaspidea’ should be considered for urban planting sites, where water supply is limited. Care should be taken when planting F. americana L., F. americana ‘Autumn Purple’ and F. velutina Torr., into urban environments as results indicated these species are sensitive to drought.