Anthropogenic Input of Selected Heavy Metals (Cu, Cr, Pb, Zn and Cd) in the Aquatic Sediments of Hochiminh City, Vietnam

The aquatic system of Hochiminh City comprises two main rivers: the Sai Gon and Nha Be rivers. Five canals discharge into these two rivers: NhieuLoc-ThiNghe, TauHu-BenNghe, TanHoa-LoGom, ThamLuong-BenCat and Doi-Te. The rivers and these canals collect effluent water from domestic and industrial sources. Most of these flows are not treated or at most are only primarily treated. A total of 33 sediment cores were taken from these rivers and canals. Chemical composition of these aquatic sediments has very high concentrations of several “urban” metals such as Cd, Cr, Cu and Zn. Most of the samples have exceeded the US EPA’s toxicity reference values for Cu, Zn and Cr (82, 82 and 70%, respectively). The highest concentrations of these metals appear to be associated with the uncontrolled and untreated industrial runoff to the discharge canals. These concentrations in fluvial sediment are relatively low, which indicates the dilution process of the contaminants. This finding indicates that the anthropogenic inputs play an important role in the elevation of heavy metals in the aquatic system and organic matter seems to exert a strong geochemical control on the amount of heavy metals. The Pearson correlation coefficients calculated for Cd, Cr, Cu and Zn, are 0.89; 0.72; 0.93 and 0.87, respectively.     

A new ent-kaurane diterpenoid from Croton tonkinensis leaves

A new ent-kaurane diterpenoid (1) was isolated from the leaves of Croton tonkinensis. The structure of 1 was determined as ent-7beta-hydroxy-15-oxokaur-16-en-18-ol from spectroscopic methods.     

Propagation of Asian isolates of canine distemper virus (CDV) in hamster cell lines

Backgrounds

The aim of this study was to confirm the propagation of various canine distemper viruses (CDV) in hamster cell lines of HmLu and BHK, since only a little is known about the possibility of propagation of CDV in rodent cells irrespective of their epidemiological importance.

Methods

The growth of CDV in hamster cell lines was monitored by titration using Vero.dogSLAMtag (Vero-DST) cells that had been proven to be susceptible to almost all field isolates of CDV, with the preparations of cell-free and cell-associated virus from the cultures infected with recent Asian isolates of CDV (13 strains) and by observing the development of cytopathic effect (CPE) in infected cultures of hamster cell lines.

Results

Eleven of 13 strains grew in HmLu cells, and 12 of 13 strains grew in BHK cells with apparent CPE of cell fusion in the late stage of infection. Two strains and a strain of Asia 1 group could not grow in HmLu cells and BHK cells, respectively.

Conclusion

The present study demonstrates at the first time that hamster cell lines can propagate the majority of Asian field isolates of CDV. The usage of two hamster cell lines suggested to be useful to characterize the field isolates biologically.     

Assessing in vivo Fertilizing Capacity of Liquid-Preserved Boar Semen According to the 'Hanover Gilt Model'

The goal of this study was to determine the ability of the Hanover gilt model to assess in vivo fertilizing capacity of preserved sperm and to consider whether any modifications to this model were needed. This model evaluates the fertilizing capacity of semen based on the fertilization rate, the rate of normal embryos and the accessory sperm count of 3–5‐day embryos. Its distinguishing characteristics are the use of one‐time insemination of sperm in reduced numbers, of spontaneously ovulating gilts and of ovulation detection through ultrasound examination of ovaries. Reduced sperm numbers allow for an accurate evaluation of the fertilizing potential of different semen treatments, thereby avoiding the compensatory effect of doses calibrated to maximize fertility. The model's usefulness was assessed in a trial run designed to compare the fertilizing capacity of liquid boar semen diluted into two different extenders. The diluent, the boar and the backflow, had no significant effect on any of the parameters studied. Gilts inseminated less than 24 h before ovulation had a significantly higher (p < 0.01) fertilization rate and accessory sperm cell count (p < 0.05) than those inseminated more than 24 h before ovulation. Very good/good embryos from homogeneous litters (only very good/good embryos were present) had a significantly higher (p < 0.01) accessory sperm count than those from heterogeneous litters (at least one embryo was of a different quality and/or oocytes were present). Both very good/good and degenerated/retarded embryos from heterogeneous litters had low accessory sperm numbers. This suggests that accessory sperm count is significantly related to the quality of the litter, but not to the quality of the embryo within gilts. It can be concluded that the Hanover gilt model is sensitive enough to show fertility differences (in this study, those associated with in vivo ageing of semen), while using relatively few gilts and little time.     

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 %.

---

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 %.

---

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 %.

     

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.     

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.     

Detection and molecular characterization of sugarcane grassy shoot phytoplasma in Vietnam

Sugarcane is an important cash crop in Vietnam and has been widely promoted at national and provincial level. In 2006, a new disease was discovered in sugarcane in the Nghean Tate&Lyle Sugar Mill in Nghean Province in north-central Vietnam. The key symptoms were the formation of green grassy shoots around the base of mature stools. We applied nested polymerase chain reaction (PCR) using P1/P7 and R16F2n/R16R2 for detection and characterization of phytoplasma from the symptomatic tissues. PCR products of the expected size (approx. 1200?bp) were obtained from the 16S rDNA of the phytoplasma. The restriction fragment length polymorphism profiles indicated that all samples were infected by the same phytoplasma. Phylogenetic analysis confirmed that the SCGS phytoplasma from Vietnam belong to the 16SrXI group, formerly Rice Yellow Dwarf group.     

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.