Potato (Solanum spp.) production using apical cuttings and tuberlets under three contrasting environments of Vietnam

Potato production from rooted apical cuttings or from small tubers (l–20g) produced in high density beds has great potential in Asia. This is particularly important in non-traditional warmer environments. This research was conducted to assess the feasibility of producing many small tubers in high density beds. A second objective compared tubers from beds with transplanted rooted cuttings and traditional seed tubers for growth and yield in the field. Tuberlet production in beds exceeded 2000/m² with a density of 1000 plants/m² under optimal growing conditions while under high temperatures only about 1.25 tuberlets/plant were produced. In field experiments, transplanted cuttings yielded 20 t/ha in the mid and high elevation areas, only slightly less than tuberlets of 5–10g while at the hot site, yields were generally only 8 to 10 t/ha for both materials. Larger healthy seed tubers produced significantly higher yields at the low and high elevation sites. Tuberlets of 1–5g were also able to give yields of 20 t/ha in the mid-elevation site. These results indicate that cuttings and small tuberlets are two ways of growing potatoes which need to be further evaluated for socioeconomic assessment by farmers.     

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.     

甜瓜属野生种Cucumis hystrix Chakr.胞质葡萄糖-6-磷酸脱氢酶基因的克隆与启动子结构分析

根据植物葡萄糖-6-磷酸脱氢酶(G6PDH,EC1.1.1.49)氨基酸保守区域,设计简并引物,采用RT-PCR技术克隆得到甜瓜属野生种Cucumis hystrix Chakr.(2n=24)G6PDH基因cDNA片段;随后基于该序列设计特异引物,PCR方法筛选野生种BAC文库,获得2个BAC阳性单克隆。测序后获得了G6PDH基因全序列及其上游启动子序列,GenBank登录号:JQ771576。序列分析显示:G6PDH基因全长约6.5 kb,由15个外显子和14个内含子组成;内含子序列均符合5’-gt-ag-3’结构。外显子拼接后获得了G6PDH基因的开放阅读框(ORF)序列,序列全长1 551 bp,编码516个氨基酸,与黄瓜基因组网站公布的G6PDH基因核苷酸序列和氨基酸序列同源性分别为98.71%和99.03%。野生种G6PDH氨基酸序列N端缺少转运肽序列,确定为野生种胞质G6PDH。氨基酸序列与烟草、马铃薯、荷兰芹、猕猴桃、拟南芥、大豆、小麦、玉米、葡萄、杨树等植物胞质G6PDH同源性高达77%以上。系统发育树分析发现,甜瓜属胞质G6PDH与茄科植物最先聚类,植物胞质G6PDH在分子进化水平上与物种进化相符。启动子结构分析表明:序列含有启动子基本元件TATA-box、CAAT-box,还含有丰富的光响应元件,与环境胁迫响应相关的不同顺式作用元件,促进高水平转录的5UTR Py-rich stretch元件和提高表达的CAT-box元件等。     

Estimates of nutrient discharge from striped catfish farming in the Mekong River,Vietnam, by using a 3D numerical model

A simulation was carried out by using a 3D numerical model for estimate the nutrient level discharged from striped catfish, Pangasianodon hypophthalmus intensively farming in the Mekong River, Vietnam. The simulated period was dry season from April 24, 2007, to April 27, 2007. Both dissolved and particulate forms of nutrients were simulated. A real status of water environment and scenario of discharge after applying fishpond effluent for irrigation of rice field were estimated in My Hoa Hung fish farm, An Giang Province. Simulated results were verified by observed data. Our results showed that nutrient levels at farming area in dry season were temporarily high and local. Applying waste water from the fishpond for irrigation of rice field could greatly reduce nutrients level in the fish farming area, the nutrient levels were 77 % for total nitrogen and 73 % for phosphorus. Therefore, recycling nutrient from fishpond effluent for irrigation of rice field illustrated an effective technology for pollution reduction which is a crucial issue to enable sustainable development of intensively farmed striped catfish.     

Is N‐feedback involved in the regulation of nitrogenase activity in Medicago truncatula?

To determine whether senescing leaves provoke an active nitrogen (N) remobilization that results in the reduction of nitrogenase activity, 60% of Medicago truncatula lower leaves were either darkened or individually excised for two weeks. Although a considerable amount of N was remobilized, N₂ fixation activity was found to be increased to maintain the N source/sink balance, indicating an absence of the negative N‐feedback regulation of nitrogenase activity in the senescing M. truncatula.     

Short-term effects of organo-mineral enriched biochar fertiliser on ginger yield and nutrient cycling

Purpose

Biochar has agronomic potential but currently is too expensive for widespread adoption. New methodologies are emerging to reduce the cost such as enriching biochar with nutrients that match crops and soil requirements. However, the effects of biochar-based fertilisers on plant yield and soil nutrient availability have not been widely examined. This study investigated the effects of a novel organo-mineral biochar fertiliser in comparison to organic and commercial biochar fertiliser on ginger (Zingiber officinale Canton).

Materials and methods

There were four treatments: (1) commercial organic fertiliser (5 t ha^?1), as the control; (2) commercial biochar-based fertiliser (5 t ha^?1); (3) organo-mineral biochar fertiliser at low rate (3 t ha^?1); and (4) organo-mineral biochar fertiliser at high rate (7.5 t ha^?1). A replicated pot trial was established with black dermosol soil and ten replicate pots for each treatment. Ginger was planted and grown for 30 weeks. Plant growth, biomass, foliar nutrients and water extractable soil nutrients including phosphorus (P), potassium (K) and calcium (Ca) were examined.

Results and discussion

High rate organo-mineral biochar fertiliser increased soil P and K availability at week 30 (harvest) after planting, compared to all other treatments and low rate organo-mineral biochar fertiliser performed similarly to the organic control for P and K. High rate organo-mineral biochar fertiliser increased total foliar nutrient content at week 30 in P, K and Ca compared to commercial biochar fertiliser. High rate organo-mineral biochar fertiliser improved the commercial value of ginger (+?36%) due to a shift in the proportion of higher grade rhizomes. Low rate organo-mineral biochar fertiliser plants displayed similar yield, total dry and aboveground biomass to commercial organic fertiliser. Commercial biochar fertiliser had significantly lower biomass measures compared with other treatments as the rate applied had lower nutrient concentrations.

Conclusions

Our results show organo-mineral biochar fertilisers could be substituted for commercial organic fertilisers at low rates to maintain similar yield or applied at high rates to increase commercial value where economically feasible.

     

Gut ecology, feed digestion and performance in weaned piglets fed liquid diets

Gut environment and microflora, digestibility, and performance were studied in weaned piglets in Central Vietnam fed a dry control diet (CO), a naturally fermented liquid diet (FE), and a liquid diet with inclusion of rice distiller's residue (RDR). Digesta samples were collected at the start (day 0) and at the end of experiment (day 42). Diet FE had a lower pH than diet RDR, contained more organic acids, had the lowest counts of E. coli and total coliforms (P < 0.05), and the highest counts of lactic acid bacteria (LAB) (P < 0.05). Piglets fed diets FE and RDR had lower pH (P < 0.05), and higher concentrations of organic acids in the stomach, ileum and mid-colon (P < 0.05) than piglets fed diet CO. Counts of LAB in stomach and ileum were higher in animals fed diets FE and RDR than CO (P < 0.05), while the number of E. coli and total coliforms along the gastrointestinal tract was reduced. The ileal digestibility of crude protein and organic matter was improved in piglets fed diet RDR (P < 0.05) compared with piglets fed diet CO. Piglets fed diet RDR had a higher weight gain (P < 0.05) and a better feed utilization (P < 0.05) than piglets fed the other diets. The present findings support the contention that fermented diets and/or fermented feedstuffs can be used for dietary manipulation to improve gut health and animal performance.     

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.     

Protecting effect of vitamin E supplementation on submaximal exercise-induced oxidative stress in sedentary dogs as assessed by erythrocyte membrane fluidity and paraoxonase-1 activity

The aim of this placebo-controlled study was to investigate the effects of oral vitamin E supplementation for 10 weeks on exercise-induced oxidative damage in untrained dogs. Eight dogs were randomly assigned to a supplementation (n = 4) or control (n = 4) group and underwent two isolated submaximal exercise sessions, 10 weeks apart. Blood was collected during each session to measure erythrocyte membrane fluidity (EMF), paraoxonase-1 (PON1) activity, plasma malondialdehyde (MDA) and vitamin E concentrations. These biomarkers were measured in venous blood samples collected before (t₀), just after (t, EMF only) and 1 d (t + 1 d) and 7 d (t + 7 d) after the dogs ran on a treadmill.Prior to vitamin E supplementation, exercise induced a significant decrease in PON1 activity, EMF, vitamin E concentration and a significant increase in MDA concentration at t + 1 d. After a 10 week vitamin E supplementation period, these exercise-induced changes in PON1 activity, EMF and MDA concentration were still significant in the control group, but not in the supplemented group. These results suggested that vitamin E supplementation had a protective effect on submaximal exercise-induced oxidative damage in sedentary dogs.     

Genetic organization of aromatic rice as revealed by RAPD markers: A case study in conserving crop genetic resources on farm

Summary On-farm conservation of landraces is one strategy to maintain the diversity of crop germplasm in local agro-ecosystems. The genetic structures of landraces are a key biological factor in on-farm conservation strategies. To accumulate a genetic understanding that will help establish a methodology for on-farm conservation, the genetic organization of landraces of aromatic rice in Namdinh province, Vietnam was analyzed using RAPD markers. Eighteen RAPD markers detected 38 genotypes among 320 aromatic rice samples growing at 23 sites of farmers' fields and in the experimental field that derived from 13 sites. Geographical variation was observed in the frequency of genotypes, whereas individual landraces could not be distinguished by RAPD markers. Genetic variation within a site was generally smaller than that among sites. The degree of genetic similarity of the plants in a site varied among sites, as did the number of genotypes. Changes in genetic structure over time were investigated using experimental populations each derived from approximately 30 plants from 13 farmers' fields. The differences detected by DNA markers between the genetic structural in the farmers' fields and those in experimental fields suggested that genetic drift is a major cause of these differences. The present study suggests that DNA markers are an essential means to monitor the genetic structures of heterogeneous landraces of rice, and are useful for selecting study sites for the on-farm conservation of genetic diversity as well as for successive monitoring.