Molecular genetic diversity and genetic structure of Vietnamese indigenous pig populations

The study characterized genetic diversity and genetic structure of five indigenous pig populations (Ha Lang, Muong Te, Mong Cai, Lung and Lung Pu), two wild pig populations (Vietnamese and Thai wild pigs) and an exotic pig breed (Yorkshire) using FAO/ISAG recommended 16 microsatellite markers in 236 samples. All estimated loci were very polymorphic indicated by high values of polymorphism information content (from 0.76 in S0225 to 0.92 in Sw2410). Indigenous populations had very high level of genetic diversity (mean He = 0.75); of all indigenous breeds, Lung Pu showed highest mean number of alleles (MNA = 10.1), gene diversity (He = 0.82), allele richness (5.33) and number of private alleles (10). Thirteen percentage of the total genetic variation observed was due to differences among populations. The neighbour‐joining dendrogram obtained from Nei's standard genetic distance differentiated eight populations into four groups including Yorkshire, two wild populations, Mong Cai population and a group of four other indigenous populations. The Bayesian clustering with the admixture model implemented in Structure 2.1 indicated seven possible homogenous clusters among eight populations. From 79% (Ha Lang) to 98% (Mong Cai). individuals in indigenous pigs were assigned to their own populations. The results confirmed high level of genetic diversity and shed a new light on genetic structure of Vietnam indigenous pig populations.     

Distribution of lipids and fatty acids in the zooxanthellae and host of the soft coral Sinularia sp.

The lipid classes and the fatty acid (FA) compositions of the zooxanthellae, the host tissue, and intact coral were determined for the first time in a soft coral, Sinularia sp. The contents of monoalkyldiacylglycerol (MADAG), triacylglycerol, and polar lipids differed significantly between the zooxanthellae and the host fractions. The zooxanthellae were rich in polar lipids, whereas neutral lipids were concentrated in the host. MADAG comprised 35% of the host lipids and was practically absent in zooxanthellae. Hence, MADAG is only synthesized in animal tissues and serves as a biomarker for the host in the host–zooxanthellae association of these soft corals. Similar to the zooxanthellae of reef-building corals, the main FA in the zooxanthellae of Sinularia sp. were 18:4n-3, 20:5n-3, and 22:6n-3. In addition, 16:3n-4 and 16:4n-1 (8.9% in total) were found in these zooxanthellae. The ratios of 16:3n-4, 16:4n-1, 18:4n-3, 20:5n-3, and 22:6n-3 in the zooxanthellae to those in the host tissue were 4.2, 11.2, 10.1, 11.0, and 9.1, respectively. The proportions of some FA and lipid classes in the intact coral and its fractions showed that zooxanthellate lipids comprised 36 ± 15% of the total lipids in Sinularia sp. Two tetracosapolyenoic acids (24:5n-6 and 24:6n-3) are proposed as a biomarkers of the animal tissue and indicators of the purity of the zooxanthellae fractions from soft corals.     

Assessment of enrichment planting of teak (Tectona grandis) in degraded dry deciduous dipterocarp forest in the Central Highlands,Vietnam

After years of unsustainable logging, dry deciduous dipterocarp forest (DDDF) has become poor in timber stocks and has been converted to industrial crops such as rubber. The objectives of this study were to assess teak (Tectona grandis L.f.) tree establishment under degraded DDDF conditions and to determine factors that influence the suitability of teak as a forest enrichment tree species. A set of 64 experimental plots of 4 900 m² each was set up and observed for 4–5 years for testing enrichment planting with teak under various combinations of two groups of factors: ecological conditions and forest status. Weighted, non-linear, multivariate regression models were used to detect key factors that influenced the suitability of teak. The results showed that at the age of 4 years the average dominant tree height (defined as 20% of the tallest trees in the experimental plot) reached 11.2, 7.8, 5.3 and 3.8 m for very good, good, average and poor suitability levels, respectively. Survival rates of planted teak from average to very good suitability levels were over 90%. Six key factors that affected the suitability of teak were waterlogging during the rainy season, altitude, stand volume of the degraded DDDF, soil type, percentage of sand and concentration of P₂O₅ in the soil. Under the extreme ecological and environmental conditions of the DDDF, enrichment planting with teak gave promising results.     

Resistance to Pseudomonas solanacearum in the potato: II. Aspects of host-pathogen-environment interaction

Summary White clover genotypes were selected for high and low values of leaf size, taproot diamater, number of taproots, proportion of total root and taproot dry weight. Crosses within selected groups of genotypes resulted in 14 seed lines, which were compared with parent genotypes in field tiles. Selections for taproot diameter and proportion taproot were more successful than those for taproot number and proportion root.Narrow sense heritability of characters calculated by regression of progeny on mid-parent values were well correlated with broad sense heritabilities derived from replicated clonal comparisons (r=0.73^*), indicating that the genetic variation is controlled predominantly by additive gene effects.     

Autoantibodies against glial fibrillary acidic protein (GFAP) in cerebrospinal fluids from Pug dogs with necrotizing meningoencephalitis

Cerebrospinal fluids (CSFs) from 9 Pug dogs with necrotizing meningoencephalitis (NME: Pug dog encephalitis) were examined to identify the antigens for anti-astrocyte autoantibodies. Each CSF exhibited a positive reaction to the cytoplasm of cultured canine astrocytes by an indirect fluorescent antibody test. In an immunoblotting analysis on normal canine brain proteins, eight of 9 CSFs showed a common band of 52 kDa, corresponding to glial fibrillary acidic protein (GFAP), and all of 9 CSFs reacted with purified bovine GFAP. From these results, GFAP is one of the common autoantigens in Pug dogs with NME. On the other hand, the reactivity of CSFs to chymotrypsin-digested bovine GFAP fragments were variable among dogs, indicating that the antibodies in the CSFs recognized different epitopes on GFAP.     

Changes in the diversity and geographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghum bicolor (L.) Moench) varieties in Niger between 1976 and 2003

Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes, we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name and type of varieties according to important traits for farmers were considered at different spatial scales (country, region, village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’ seed systems.     

Effects of dietary arachidonic acid on final maturation,spawning and composition of gonad of black sea urchin Diadema setosum (Leske, 1778)

This study investigated the effect of dietary arachidonic acid (ARA, 20:4n‐6) on final maturation, spawning performance and composition of the gonad of black sea urchin (Diadema setosum). Four different dietary ARA levels of 0.3 g/kg (Control diet), 1.4 g/kg (ARA 1.4), 2.5 g/kg (ARA 2.5) and 3.7 g/kg (ARA 3.7) were prepared and tested in this feeding trial for 90 days. The result showed that growth in terms of weight was not relatively affected by dietary ARA. Gonadosomatic Index (GSI) of animals were gradually increased in all the diets throughout the trial. The highest GSI level (25.7 ± 3.16%) was observed in animals fed with the diet ARA 1.4. ARA content in the gonad proportionally increased with dietary ARA levels. The highest larval survival rate (85.5 ± 5.67%) was found in diet ARA 2.5. The results of this study indicate that ARA plays an important role in the reproduction functions of black sea urchin and supplementing an appropriate level of ARA in the broodstock diet could induce the final maturation and improve reproduction of black sea urchin, but a higher level of ARA (3.7 g/kg) seems to have a negative effect on both growth rate and GSI.     

Evaluation of cottonseed and soybean meal as partial replacement for fishmeal in diets for juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

This study was conducted to investigate the effect of dietary supplementation of cottonseed and soybean meal (CS) on growth performance, feed utilization, and gossypol accumulation in juvenile (mean body weight 11 g) Japanese flounder Paralichthys olivaceus. Five isonitrogenous and isocaloric experimental diets (designated CS0, CS10, CS20, CS30, and CS40) containing 0, 10, 20, 30, and 40% CS mixture (1∶1 w/w) were formulated. After 9 weeks of feeding trial, fish fed all diets did not show significant differences in growth performances, feed utilization, and whole body compositions. Hemoglobin content gradually decreased (P<0.05) with increments of CS inclusion levels. There was a positive linear relationship between dietary gossypol and total liver gossypol contents. Free radical scavenging activity in the experimental diets gradually increased with increment of dietary CS inclusion. This finding indicates that the mixture of cottonseed and soybean meal with methionine and lysine supplementation could replace up to 40% of fishmeal protein in diets. However, 20% fishmeal protein replacement by dietary inclusion of cottonseed (9.4%) and soybean (8.7%) meal might be the optimum and safe level for the commercial use of CS in juvenile Japanese flounder.     

Antagonism of local isolates of Trichoderna spp. on citrus root rot disease by Fusarium solani in the mekong delta of vietnam

The local isolates of Trichoderrma spp. and Fusariun solani were colected from citrus orchards in the Mekong delta of Vietnam and isolated on PDA, PDB and TSM medium for antagonism and Koch's postulate testing. The results showed that the high chitinolytic enzymes content of Trichoderma isolates can antagonise with Fusarium solani isolates by preventing the germination of Fusarium macroconidia in in-vitro condition. There are five promising isolates of Trichoderna spp. having high antagonism with Fusarium solani. These Trichoderma isolates also grew well in rice straws, maize stems, weeds and water hyacinth biowaste materials. These results supply the promising trend for biological control of root rot disease on citrus orchards of the Mekong delta.     

聚碳酸酯板材多点热成形数值模拟与成形精度分析

提出了用于热塑性聚合物板材的柔性成形技术——多点热成形技术。根据高温单向拉伸试验数据确定了不同温度下聚碳酸酯(PC)板材的超弹性材料模型参数。运用有限元软件Abaqus对不同温度和不同成形压力下的PC板材多点热成形过程进行了数值模拟,结果表明:当成形温度与成形压力分别为160℃和10 kPa时,成形件平均形状误差最小。参照数值模拟结果进行了PC板材的多点热成形试验,验证了数值模拟结果的准确性。测量并分析了成形件的成形精度,结果表明:成形件具有较高的成形精度,可以满足工程应用需要。