Simple allele-discriminating PCR for cost-effective and rapid genotyping and mapping

Background  

Single nucleotide polymorphisms (SNPs) are widely observed between individuals, ecotypes, and species, serving as an invaluable molecular marker for genetic, genomic, ecological and evolutionary studies. Although, a large number of SNP-discriminating methods are currently available, few are suited for low-throughput and low-cost applications. Here, we describe a genotyping method named Simple Allele-discriminating PCR (SAP), which is ideally suited for the small-scale genotyping and gene mapping routinely performed in small to medium research or teaching laboratories.     

Seed Development, Maturation and Storage Behaviour of Mimusops elengi L.

Mass maturity (end of the seed-filling phase) occurred at about 72 days after flowering (DAF) in developing seeds of Mimusops elengi, at which time seed moisture content had declined to about 55%. The onset of ability to germinate was detected at 56 DAF and seeds showed 98% germination by 84 DAF. Tolerance of desiccation to 10% moisture content was first detected at 70 DAF and was maximal by 84 DAF. Delaying collection by a further 14 days to 98 DAF, when fruits began to be shed, reduced seed viability, particularly for seeds first dried to 10% moisture content. Hence the best time for seed collection appears to be about 14 days before fruits shed. In a separate investigation with six different seed lots, desiccation below about 8–12% moisture content reduced viability (considerably in some lots). The viability of dry seeds (below about 10% moisture content) stored hermetically was reduced at cool temperatures (5 °C and below), and none survived storage at sub-zero temperatures. The results suggest that Mimusops elengi shows intermediate seed storage behaviour and that the optimal hermetic seed storage environment is about 10% moisture content at 10 °C, while short-term, moist, aerated storage at high (40%) moisture content is also feasible.     

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.     

Effects of Energy and Protein Supplementation on the Production and Economic Efficiency of Scavenging Improved (Tamhoang) and Local (Ri) Breed Hens under Smallholder Conditions in North Vietnam

The objectives of this study were to evaluate the effects of supplementing maize meal and soybean meal, separately or mixed, on egg production performance of two breeds of scavenging hens under on-farm conditions. Treatments were: (1) confined, with a mixed feed (75% maize meal and 25% soybean meal) ad libitum (CMF); (2) scavenging, with a supplement of 60 g/bird per day of maize meal (ScM); (3) scavenging, with a supplement of 25 g/bird per day of soybean meal (ScS); (4) scavenging, with 54 g/ bird per day of the mixed feed (ScMF). Mean hen-day production was 21.8%, 19.8%, 17.7% and 22.8% for the CMF, ScM, ScS and ScMF treatments, respectively (p <0.05), and was significantly (p <0.001) higher for the improved Tamhoang breed (24.4%) than for the local Ri hens (16.7%). Mean egg weight was significantly higher for the Tamhoang (53.2 g) compared to the Ri hens (45.0 g) (p<0.01). Feed consumption per kilogram of eggs was significantly higher for the CMF treatment compared to the other treatments and was lower for the ScS compared to the other scavenging treatments (p <0.05). Feed cost per kilogram of eggs was lowest for the ScM treatment and was 30 to 40% higher for the confined treatment compared to the scavenging treatments. Feed consumption and cost of feed per kilogram of eggs were significantly lower for the Tamhoang than for the Ri hens.     

Non‐Typhoidal Salmonella Colonization in Chickens and Humans in the Mekong Delta of Vietnam

Salmonellosis is a public health concern in both the developed and developing countries. Although the majority of human non‐typhoidal Salmonella enterica (NTS) cases are the result of foodborne infections or person‐to‐person transmission, NTS infections may also be acquired by environmental and occupational exposure to animals. While a considerable number of studies have investigated the presence of NTS in farm animals and meat/carcasses, very few studies have investigated the risk of NTS colonization in humans as a result of direct animal exposure. We investigated asymptomatic NTS colonization in 204 backyard chicken farms, 204 farmers and 306 matched individuals not exposed to chicken farming, in southern Vietnam. Pooled chicken faeces, collected using boot or handheld swabs on backyard chicken farms, and rectal swabs from human participants were tested. NTS colonization prevalence was 45.6%, 4.4% and 2.6% for chicken farms, farmers and unexposed individuals, respectively. Our study observed a higher prevalence of NTS colonization among chicken farmers (4.4%) compared with age‐, sex‐ and location‐ matched rural and urban individuals not exposed to chickens (2.9% and 2.0%). A total of 164 chicken NTS strains and 17 human NTS strains were isolated, and 28 serovars were identified. Salmonella Weltevreden was the predominant serovar in both chickens and humans. NTS isolates showed resistance (20–40%) against tetracycline, chloramphenicol, sulfamethoxazole‐trimethoprim and ampicillin. Our study reflects the epidemiology of NTS colonization in chickens and humans in the Mekong delta of Vietnam and emphasizes the need of larger, preferably longitudinal studies to study the transmission dynamics of NTS between and within animal and human host populations.     

Molecular cloning of the swine interleukin-23 subunit p19 and of its receptor components interleukin-23Rα and -12Rβ1

Interleukin (IL)-12 and IL-23 play central roles in the regulation of distinct helper T-cell subsets, i.e. Th1 and Th17, respectively. Although IL-12 and IL-23 have been well studied in human and rodent systems, little is known about their significance in other animals, including livestock mammals such as cattle and pigs. In this study, we performed molecular cloning and genetic characterization of a small component of swine IL-23, i.e., IL-23p19; in addition, we identified and performed chromosomal assignment of the genes encoding its receptor (R) subunits IL-23Rα and IL-12Rβ1. These results provide genetic information about both swine IL-23/IL-23R and IL-12/IL-12R systems, which allows for better understanding of IL-12/IL-23 systems involved in pig immunity.     

竹柳枝桠材重组木的研制

以幼龄竹柳枝桠材为原料,通过对竹柳枝桠材酸碱性、密度、干缩性、表面接触角以及密度、施胶量对竹柳重组木物理力学性能的影响进行研究。结果表明,竹柳枝桠材的pH为6．43～6．46,呈弱酸性,酸碱缓冲容量为34．63～38．94 mL,全干干缩率为1．86,气干干缩率为1．91;利用表面张力测量仪测得,竹柳枝桠材外表面MUF接触角为54．52°,内表面为37．27°。在板材密度0．9 g／cm3、三聚氰胺改性脲醛树脂（MUF）施胶量14％、热压温度160℃、加压时间20 min、木束含水率6％条件下制得的竹柳重组木弹性模量为12948．68 MPa,达到GB／T 4897．7—2003《刨花板》的要求;静曲强度为105．08 MPa,内结合强度为2．07 MPa,2 h吸水厚度膨胀率为3．49％,其值均达到了LY／T 1984—2011《重组木地板》的要求。SEM图像表明MUF 压制的竹柳重组木的管孔被压缩成椭圆形,但细胞壁本身并没有被压溃,仍然保持了其完整性;红外光谱仪测试结果表明,竹柳的纤维素和半纤维素均与胶黏剂发生反应,存在化学键的结合。     

Nematicidal and antifungal activities of annonaceous acetogenins from Annona squamosa against various plant pathogens

The methanol extract of Annona squamosa seeds was highly active against two phytoparasitic nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. It efficiently suppressed plant diseases, caused by Phytophthora infestans and Puccinia recondita. Ten annonaceous acetogenins (AAs) were isolated, and their chemical structures were identified by mass and nuclear magnetic resonance spectral data. Out of 10 substances, eight displayed strong in vitro nematicidal activity against B. xylophilus with LD(50) values ranging 0.006 to 0.048 μg/mL. Squamocin-G showed potent nematicidal activity against M. incognita. Squamocin, squamocin-G, and squamostatin-A also displayed potent in vitro and in vivo antifungal activities against P. infestans causing tomato late blight. In addition, squamostatin-A effectively controlled the development of wheat leaf rust caused by P. recondita. Our findings suggested that A. squamosa seeds and its bioactive AAs can be an alternative resource of a promising botanical nematicide and fungicide to control various plant diseases.     

Homodimeric β-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081: expression in Lactobacillus plantarum and biochemical characterization

The lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081, encoding a β-galactosidase of the glycoside hydrolase family GH2, was cloned into different inducible lactobacillal expression vectors for overexpression in the host strain Lactobacillus plantarum WCFS1. High expression levels were obtained in laboratory cultivations with yields of approximately 53000 U of β-galactosidase activity per liter of medium, which corresponds to ~170 mg of recombinant protein per liter and β-galactosidase levels amounting to 63% of the total intracellular protein of the host organism. The wild-type (nontagged) and histidine-tagged recombinant enzymes were purified to electrophoretic homogeneity and further characterized. β-Galactosidase from L. bulgaricus was used for lactose conversion and showed very high transgalactosylation activity. The maximum yield of galacto-oligosaccharides (GalOS) was approximately 50% when using an initial concentration of 600 mM lactose, indicating that the enzyme can be of interest for the production of GalOS.