Les vitamines du groupe B dans les aliments végétaux au Sud Vietnam

Résumé Les recherches sur la teneur en vitamines du groupe B (thiamine, riboflavine, nicotinamide) faites sur 135 végétaux alimentaires du Sud Vietnam, montrent que les plantes riches en thiamine sont rares; ce sont surtout les graines et quelques rares feuilles(Sesbania grandiflora Pers. 0,365 mg% de partie comestible) et fruit (pulpe deTamarindus indica L. 0,374 mg %:Durio Zibethinus Murr. 0,300 mg %).Les bonnes sources de riboflavine sont aussi rares mais ce sont essentiellement les légumes à feuilles vertes dont spécialementIpomoea aquatica Forsk. 0,500 mg % et un champignonVolvaria esculenta Massee 0,350 mg %.Enfin la nicotinamide se trouve en quantité importante dans les plantes alimentaires étudiées et sa répartition est assez variée. Les teneurs les plus élevées se trouvent dans les graines comme:Arachis hypogea L. 12 mg %,Citrullus vulgaris Schrad. 8,450 mg %Sesamum indicum L. 5,970 mg %.

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Summary The vitamins of the B group (thiamine, riboflavine, nicotin amide) were analysed in 135 edible plants from South-Vietnam. The plants rich in thiamine are rare; some seeds, rarer leaves(Sesbania grandiflora Pers. 0.365 mg % of the edible part) and fruits (pulp ofTamarus Indica L. 0.374 mg %,Durio Zibethinus Murr 0.3 mg %) were found.The rich sources of riboflavine are equally rare; into the group belong especially green leaves, in particularIpomoea aquatica Forsk, 0.5 mg % and a fungus,Volvaria esculenta Massee 0.35 mg %.Nicotinamide is found in greater quantities in the analysed plants, the allotment being rather great. The greatest amounts have been found in the seeds:Arachis hypogea L. 12 mg %,Citrullus vulgaris Schrad 8.45 mg %Sesamum Indicum L. 5.97 mg %.

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Zusammenfassung Die Vitamine der B-Gruppe (Thiamin, Riboflavin, Nicotinsäureamid) wurden in 135 essbaren Pflanzen aus Süd-Vietnam bestimmt. Thiamin-reiche Pflanzen sind selten: manche Samen, seltener manche Blätter,(Sesbania grandiflora Pers. 0,365 mg % des essbaren Teiles) und Früchte (Fleisch vonTamarindus indica L. 0,374 mg %,Durio Zibethinus Murr 0,3 mg %).Gute Quellen an Riboflavin sind ebenso selten. Solche sind besonders grüne Blätter, namentlich vonIpomoea aquatica Forsk, 0,5 mg %, und ein Pilz,Volvaria esculenta Massee 0,35 mg %.Nicotinsäureamid findet sich in wechselnden Mengen in den untersuchten Pflanzen. Die höchsten Gehalte sind in Samen zu finden:Arachis hypogea L. 12 mg %,Citrullus vulgaris Schrad. 8,45 mg %,Sesamum indicum L. 5,97 mg %.

     

Prevalence of Salmonella spp. in pigs, chickens and ducks in the Mekong Delta, Vietnam

In order to determine the prevalence of Salmonella spp. in domestic animals in 6 provinces of the Mekong Delta, Vietnam, 1,098 fecal or intestinal content samples from pigs, chickens, and ducks were examined in the period from July to October, 2000. Salmonella spp. were isolated from 78 (7.1%) of the total samples, which included 23 (5.2%) of 439 pigs, 24 (7.9%) of 302 chickens, and 31 (8.7%) of 357 ducks. From those samples, 80 Salmonella strains were isolated and 25 serovars were identified. The predominant serovars were S. Javiana, S. Derby, and S. Weltevreden. S. Javiana and S. Weltevreden were detected together in pigs, chickens, and ducks. These results indicate that the serovars of Salmonella are widely distributed in domestic animals in the Mekong Delta, Vietnam.     

Converting ceria polyhedral nanoparticles into single-crystal nanospheres

Ceria nanoparticles are one of the key abrasive materials for chemical-mechanical planarization of advanced integrated circuits. However, ceria nanoparticles synthesized by existing techniques are irregularly faceted, and they scratch the silicon wafers and increase defect concentrations. We developed an approach for large-scale synthesis of single-crystal ceria nanospheres that can reduce the polishing defects by 80% and increase the silica removal rate by 50%, facilitating precise and reliable mass-manufacturing of chips for nanoelectronics. We doped the ceria system with titanium, using flame temperatures that facilitate crystallization of the ceria yet retain the titania in a molten state. In conjunction with molecular dynamics simulation, we show that under these conditions, the inner ceria core evolves in a single-crystal spherical shape without faceting, because throughout the crystallization it is completely encapsulated by a molten 1- to 2-nanometer shell of titania that, in liquid state, minimizes the surface energy. The principle demonstrated here could be applied to other oxide systems.     

Comparison of Vietnamese and European pig breeds using microsatellites

This study characterized autochthonous pig breeds of Vietnam and compared them with breeds from other regions. A total of 343 animals were considered from 5 indigenous pig breeds of Vietnam (Muong Khuong, Co, Meo, Tap Na, and Mong Cai), 2 exotic breeds kept in Vietnam (Landrace and Yorkshire), 3 European commercial breeds (German Land-race, Piétrain, and Large White), the Chinese breed Meishan, and the European Wild Boar. Each individual was genotyped for 20 selected polymorphic microsatellite loci. The Vietnamese autochthonous breeds showed higher degrees of polymorphism, allelic diversity, and heterozygosity than the other pig breeds. Also, large genetic diversity was observed across the area of distribution, with village-specific subpopulations, which led to significant inbreeding coefficients. As expected, genetic distances showed large differences among European-based, Chinese, and Vietnamese indigenous breeds and reflected the geographical distribution of breeds. In comparison with the European breeds, the Vietnamese indigenous pig breeds harbored a considerable amount of genetic diversity and, therefore, will be of significance for livestock bioconservation.     

Identification of a novel locus Rmo2 conditioning resistance in barley to host-specific subgroups of Magnaporthe oryzae

Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome.     

Comparison of production systems for efficient use of indigenous pig breeds in developing countries

Conserving pig genetic resources and improving their productivity is important to increase returns over investment in developing countries. The purebred, first‐cross, rotational cross and backcross matings representing production systems based on pig breeds indigenous to the country and exotic pig breeds were investigated. The number of pigs in the nucleus and commercial herds necessary to produce a defined quantity of pork was considered. The amount of heterosis between the indigenous and exotic breeds, superiority in meat production, and degree of inferiority in reproductive performance of the exotic breed compared with that of the indigenous breed were investigated. The number of breeding pigs in the whole system was in the following order: pure breeding (PB) > first‐cross (F1) > rotational cross (RC) > backcross (BC) systems. The number of breeding pigs in the nucleus herds of the RC and BC systems was smaller than that in the nucleus herds of the PB and F1 systems. The degree of inferiority in reproductive performance of the exotic breed compared with that of the indigenous breed affected the efficiency of the production system.     

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.     

The Contribution of Various Components to pH Buffering Capacity of Acrisols in Southeastern Vietnam

This paper examined the contribution of various soil components to pH buffering capacity (pH_BC) of haplic Acrisols in an upland area of Southeastern Vietnam. Sampling was conducted in 2016 in Tan Bien district, Tay Ninh province at seven sites from the surface to 60-cm depth. Soils were very acidic (pH_H2O 4.53 ± 0.05). The pH_BC were very low, 0.46 ± 0.04 and 0.44 ± 0.05 cmol H⁺ kg^?1 pH^?1, respectively, for original samples and those from which soil organic carbon (SOC, 0.52 ± 0.09%) were removed. The contribution of Al³⁺ to pH_BC was remarkable while that of SOC was of little significance. The contribution of clay minerals to pH_BC was unclear due to the low (9.37 ± 0.76%) and kaolinite-dominated clay content. The current soil conditions indicated a potential for further soil acidification. Liming would be one of the measures to remediate soil acidity in the research area.     

Short-term carbon and nitrogen dynamics in soil,litterfall and canopy of a suburban native forest subjected to prescribed burning in subtropical Australia

Purpose

This study aimed to understand the mechanisms of the variations in carbon (C) and nitrogen (N) pools and examine the possibility of differentiating the burning effects from seasonal and pre-existed N limitations in a native suburban forest ecosystem influenced by prescribed burning in subtropical Australia.

Materials and methods

Soil and litterfall samples were collected from two study sites from 1 to 23 months since last burnt. Soil labile C and N pools, soil C and N isotopic compositions (δ¹³C and δ¹⁵N), litterfall mass production (LM), and litterfall total C, total N, δ¹³C and δ¹⁵N were analysed. In-situ gas exchange measurements were also conducted during dry and wet seasons for Eucalyptus baileyana and E. planchoniana.

Results and discussion

The results indicated that labile C and N pools increased within the first few months after burning, with no correlations with climatic factors. Therefore, it was possible that the increase was due to the burning-induced factors such as the incorporation of ashes into the soil. The highest values of soil and litterfall δ¹⁵N, observed when the study was commenced at the experimental sites, and their high correlations with climatic factors were indicative of long-term N and water limitation. The ¹³C signals showed that soil N concentrations and climatic factors were also two of the main factors controlling litterfall and foliage properties mainly through the changes in photosynthetic capacity and stomatal conductance.

Conclusions

Long-term soil N availabilities and climatic factors were the two of the main driving factors of C and N cycling in the studied forest sites. Further studies are needed to compare soil and litterfall properties before and after burning to profoundly understand the effects of prescribed burning on soil labile C and N variations.