Genotyping canine distemper virus (CDV) by a hemi-nested multiplex PCR provides a rapid approach for investigation of CDV outbreaks

CDV is a highly contagious viral pathogen causing a lethal systemic disease in dogs and other carnivores. Several lineages or genotypes of CDV exist that are variously distributed throughout several continents. Legal or uncontrolled trading of animals may modify the epidemiology of CDV, introducing novel strains in CDV-na?ve areas or accounting for the resurgence of CDV in areas where vaccine prophylaxis was effective and successful to control the disease. A hemi-nested PCR system was developed to genotype strains of the major CDV lineages, America-1, Europe, Asia-1, Asia-2 and Arctic. The assay was tested using a collection of 27 laboratory and vaccine strains and of 36 field CDV strains. Distinct lineages could be differentiated by specific primers targeted to the H gene. The method could be useful for molecular epidemiological studies of CDV, providing a tool for large-scale studies, and for the diagnosis of vaccine-related disease.     

Diversity among germplasm lines of the Ethiopian cereal tef [ Eragrostis tef (Zucc.) Trotter]

Three hundred twenty germplasm lines of the major Ethiopian cereal, tef, [ Eragrostis tef (Zucc.) Trotter], were evaluated for 20 morphological, phenological and agronomic characters in two-replicated randomized complete blocks at Debre Zeit and Melkassa Agricultural Research Centers in Ethiopia during the 1995 main season. The objectives were to assess the diversity of the lines, and to estimate the broad sense heritability (H) and genetic advance (GA) of the various characters. The mean squares of genotypes were highly significant (p ≤ 0.001) for all the traits. The phenotypic and genotypic coefficients of variation ranged in that order from about 6–40% and 3–23% for days to maturity and grain yield/plant, and days to maturity and number of spikelets/main shoot panicle, respectively. The cluster analysis grouped the genotypes into 14 major complexes consisting of one to 183 lines. Of the 19 principal components involved in explaining the entire variation among the genotypes the first five which had eigenvalues of more than one explained about 73.8%. The first principal component which accounted for about 34% of the total variance was due chiefly to plant height, culm and panicle length, diameters of the two basal culm internodes, main shoot panicle mass and grain yield, number of main shoot panicle branches and spikelets, and days to panicle emergence and maturity. Estimates of H varied from about 22% for length of the lowest main shoot stem internode to 74% for number of main shoot panicle branches. Values of GA (expected from selection of the superior 5% of the lines and expressed relative to the means) ranged from about 3% for days to maturity to 36% for number of spikelets/main shoot panicle. Overall, the study indicated the existence of trait diversity in tef germplasm and this can be exploited in the genetic improvement of the crop through hybridization and selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bacterial population in intestines of white shrimp,Litopenaeus vannamei fed a synbiotic containing Lactobacillus plantarum and galactooligosaccharide

The aims of this study were to unravel the intestinal microbiota of Litopenaeus vannamei after being fed a diet without (control) or with the synbiotic (SYN) for 60 days using next‐generation sequencing technology to see if changes in the intestinal microbiota were involved in the improved growth performance and health status of the shrimp. Next‐generation sequencing data showed that six phyla, 11 classes, 19 orders, 30 families, 58 genera and 73 species with taxonomic names assigned were detected. The majority of the operational taxonomic units (OTUs) was shared between the SYN and control shrimp and comprised 37 OTUs. However, intestinal biodiversity analyses revealed that SYN‐fed shrimp had a higher species richness, evenness and Shannon–Weaver index than did shrimp fed the control diet, but without reaching statistical significance. Interestingly, shrimp fed the SYN diet exhibited improved colonization of Lactobacillus plantarum and reduced prevalences of Vibrio harveyi and Photobacterium damselae in the intestines. These findings indicate that the SYN was able to modulate the intestinal bacterial community of shrimp and could be used to control vibriosis in shrimp.     

Methionine Requirement in Practical Diets of Juvenile Nile Tilapia,Oreochromis niloticus

Two feeding experiments were conducted to confirm methionine requirement in practical diets of juvenile Nile tilapia, Oreochromis niloticus. Test diets used in both experiments contained 414 kcal gross energy, 28 g protein, and 5 g lipid per 100 g diet. In the first experiment, seven diets were made using cottonseed meal (CSM), dehulled solvent‐extracted soybean meal (DSESM), and gelatin as intact protein sources. Methionine was added to five of these diets at 0.03 or 0.06% increments to produce methionine levels ranging from 0.33 to 0.57% of the diet. Each diet was fed to four replicate groups of male juvenile Nile tilapia (5.62 ± 0.13 g) in a recirculation system for 8 wk. Broken‐line regression analysis of weight gain indicated that methionine requirement of juvenile Nile tilapia was 0.49% of the diet or 1.75% of dietary protein at cystine level of 0.45% of the diet. The second experiment was designed based on methionine requirement determined in the first experiment and also contained seven test diets. The first six diets contained CSM and DSESM as protein sources. Methionine was added to five of these diets at an increasing rate of 0.06% to produce methionine levels ranging from 0.49 to 0.79% of the diet. In the last diet (Diet 7), a portion of DSESM was replaced by gelatin to reduce methionine level to 0.33% of the diet in order to test whether methionine is limited. Each diet was also fed to four replicate groups of male juvenile Nile tilapia (2.32 ± 0.06 g) in a recirculation system for 9 wk. At the termination of the second experiment, there were no significant differences in terms of weight gain, survival, and feed efficiency ratio (FER) among the fish fed the first six diets. However, weight gain and FER of the fish fed these diets were significantly better than those fed Diet 7, confirming the methionine requirement value as has been determined in the first experiment.     

Quantification of DNA of citrus huanglongbing pathogen in diseased leaves using competitive PCR

A quantification system for huanglongbing pathogen using a competitive polymerase chain reaction method and image-analyzing software were developed to obtain precise results. Significant differences in the quantity of pathogen were thus determined in leaves of two citrus cultivars commonly cultivated in southern Vietnam. Less pathogen-related DNA was detected from the tissue of citrus cultivars that are believed to be more tolerant than susceptible cultivars. The quantification system will be used in studies on pathogen proliferation and movement inside citrus tissue.     

Bordetella bronchiseptica aroA mutant as a live vaccine vehicle for heterologous porcine circovirus type 2 major capsid protein expression

Porcine circovirus type 2 (PCV2) infections cause important respiratory diseases in the pig industry and are associated with many bacterial, mycoplasmal, and viral complications. In this study, a heterologous PCV2 major capsid protein (MCP) was expressed in the Bordetella bronchiseptica aroA mutant strain (BBS-MCP) and used as a live vaccine vehicle. Mice and pigs were immunized with live BBS-MCP via the intranasal route. The antibodies against MCP were induced successfully in the serum as determined by ELISA. In the PCV2 challenge experiment, viral DNA was removed successfully from the lymph nodes of pigs vaccinated with live BBS-MCP. Overall, BBS-MCP is believed to be a good candidate for the development of a live-attenuated vaccine against PCV2 infections.     

辐射花粉授粉技术诱导黄瓜单倍体

辐射花粉授粉是获得单倍体的有效途径。本研究旨在探讨该途径中影响单倍体再生率的关键因素。本试验利用60Coγ对不同黄瓜材料进行不同剂量的辐射处理,系统研究了辐射剂量、花粉供体基因型、母本基因型对诱导黄瓜单倍体植株再生率的影响。结果表明:3个花粉供体基因型(5211、CC3、南抗一号)花粉经150 Gy辐射处理后,花粉供体基因型5211诱导的植株再生率、单倍体再生率均高于花粉供体基因型CC3和南抗一号。花粉供体在辐射剂量150 Gy辐射处理下较250 Gy及350 Gy更有利于诱导植株再生,再生率最高可达3.92%,单倍体再生率为1.96%。10个母本基因型中6个母本基因型没有诱导出再生植株,占母本基因型总量的60%;4个母本基因型诱导出再生植株,占母本基因型总量的40%,单倍体诱导率为0.26~0.54。     

Anti-Inflammatory Components of the Starfish Astropecten polyacanthus

Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer’s disease, Parkinson’s disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC₅₀ values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the production of IL-12 p40 with values of 6.55 ± 0.18 and 5.06 ± 0.16 μM, respectively. Moreover, compounds 2 (IC₅₀ = 34.86 ± 0.31 μM) and 6 (IC₅₀ = 79.05 ± 2.05 μM) exhibited moderate inhibitory effects on the production of IL-12 p40, whereas compounds 3 (IC₅₀ = 22.80 ± 0.21 μM) and 4 (IC₅₀ = 16.73 ± 0.25 μM) moderately inhibited the production of TNF-α and IL-6, respectively.