Antagonism of local isolates of Trichoderna spp. on citrus root rot disease by Fusarium solani in the mekong delta of vietnam

The local isolates of Trichoderrma spp. and Fusariun solani were colected from citrus orchards in the Mekong delta of Vietnam and isolated on PDA, PDB and TSM medium for antagonism and Koch's postulate testing. The results showed that the high chitinolytic enzymes content of Trichoderma isolates can antagonise with Fusarium solani isolates by preventing the germination of Fusarium macroconidia in in-vitro condition. There are five promising isolates of Trichoderna spp. having high antagonism with Fusarium solani. These Trichoderma isolates also grew well in rice straws, maize stems, weeds and water hyacinth biowaste materials. These results supply the promising trend for biological control of root rot disease on citrus orchards of the Mekong delta.     

Changes in the diversity and geographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghum bicolor (L.) Moench) varieties in Niger between 1976 and 2003

Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes, we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name and type of varieties according to important traits for farmers were considered at different spatial scales (country, region, village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’ seed systems.     

Anesthetic synergy between two n-alkanes

Objective

N-butane and n-pentane can both produce general anesthesia. Both compounds potentiate γ-aminobutyric acid type A (GABA_A) receptor function, but only butane inhibits N-methyl-d-aspartate (NMDA) receptors. It was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels.

Changes in brain and pituitary GnRH levels during ovarian maturation in wild female Japanese flounder

To elucidate the role of gonadotropin-releasing hormone (GnRH) in gonadal maturation in wild female Japanese flounder Paralichthys olivaceus, we monitored changes in the levels of seabream GnRH (sbGnRH) in the olfactory bulb, telencephalon, hypothalamus, and pituitary during ovarian development together with changes in plasma levels of testosterone (T), estradiol-17β (E₂), and 17α, 20β-dihydroxy-4-pregnen-3-one (DHP). Fish were caught offshore of the northern mainland of Japan in the Pacific Ocean at 3- to 4-week intervals between April and September by gill net. The netted fish were categorized into six groups based on ovarian stages: previtellogenic (April–early May), early yolk (April–late May), late yolk (late May–June), early spawning (June–August), late spawning (September), and termination (September) stages. The gonadosomatic index significantly increased from the previtellogenic to early spawning stages and decreased thereafter. In the olfactory bulb, no significant differences were observed in sbGnRH levels among the developmental stages. In contrast, sbGnRH levels in the telencephalon and hypothalamus were very high in the previtellogenic stage, lower in the early spawning stage, and relatively high in latter stages. sbGnRH levels in the pituitary were high in the previtellogenic stage and low in the early spawning stage. In addition, the relatively high levels of pituitary sbGnRH were found together with high plasma T, E₂, and DHP levels in fish in the late yolk stage. These results indicate that sbGnRH in the telencephalon, hypothalamus, and pituitary is involved in ovarian maturation and that sbGnRH may play an important role in the initiation of ovarian recrudescence in wild Japanese flounder.     

枯草芽孢杆菌B2菌株产生的抑菌活性物质分析

枯草芽孢杆菌B2菌株产生的胞外物质经盐酸沉淀，甲醇抽提获得粗制备物。利用HPLC系统将粗制备物过Xterra RPl8层析柱分离，共获得120管收集液。以抑制小麦赤霉病菌分生孢子萌发为指标对各管收集液的抑菌活性进行了测定。通过LC-MS分析，结果表明B2菌株胞外存在3种抑菌物质，即脂肽类抗生素表面活性素、多烯类和一种分子量为564的结构未知的新物质。     

Evaluation of genetic richness among Vietnamese native pig breeds using microsatellite markers

We have elucidated genetic relationships of Vietnamese native pigs (VNP) using preliminarily collected samples by a single‐nucleotide polymorphism (SNP) array. In order to confirm our previous results and compare with the results of a previous study using microsatellite (MS) markers, we aimed to characterize genetic diversity and population structure in wider varieties (24 breeds from 21 Provinces) of VNP across the country using 20 polymorphic MS markers recommended by ISAG/FAO (International Society for Animal Genetics/Food and Agriculture Organization) for diversity study. In this study, we collected 1,136 DNA samples of the VNPs and three exotic breeds. Our results revealed that the average number of alleles and allelic richness across the loci in VNPs were 10.0 and 7.6, which were higher than those of exotic breeds. Genomic components among VNPs were subjected to the sampling locations. Interestingly, Co Binh Thuan showed remarkable genetic feature compared to the other VNPs, because the habitation of Co Binh Thuan was relatively far from the other breeds. The results of this study provided useful information for exploitation, conservation, and development trends of the VNP breeds. More recently, African swine fever caused significant damage to most of the VNP populations. Therefore, our findings will help a reconstruction scheme of the VNP genetic resources.     

Reliable detection of unevenly distributed Verticillium dahliae in diseased olive trees

Verticillium wilt caused by Verticillium dahliae is one of the most threatening diseases of olive worldwide. For pre‐planting and post‐planting control of verticillium wilt in olive trees, availability of a rapid, reliable and non‐destructive method for detection of V. dahliae is essential. For such a method, suitable and easily performed sampling and efficient processing of samples for extraction of DNA are necessary. In this study, the suitability of young twig and leaf samples of olive trees, which are easy to collect and extract DNA from, were assessed for the detection of V. dahliae in routine procedures. The lower (about 50 cm from the tip) and top parts (about 5 cm from the tip) of twigs, as well as leaves from infected olive trees were screened for V. dahliae infection and distribution using real‐time PCR. The biomass of V. dahliae detected in individual twigs was highly variable, but there was no significant difference between mean quantities of V. dahliae DNA detected in top and lower parts of twigs. Furthermore, it was demonstrated that analysis of combined samples containing DNA extracted from five twigs of an infected tree accurately detected the presence of the pathogen. Similarly, testing combined samples of 5–10 leaves enabled reliable detection of the pathogen in an infected tree. The development of this assay enables reliable detection of V. dahliae in infected olive trees that can aid in management decisions for the implementation of integrated disease management.     

The effects of permanent magnetic fields on in vitro growth of Phalaenopsis plantlets

Summary

This is the first study to address the effects of permanent magnetic fields (MFs) on the in vitro growth of Phalaenopsis plantlets. Uniform Phalaenopsis Gallant Beau ‘George Vazquez’ plantlets, each with two leaves and two roots, and each approx. 2 cm in height, were excised from a mass of protocorm-like bodies (PLBs) after 3 months of sub-culture. The plantlets (n = 21) were cultured in a film culture system (‘Miracle Pack’^®) under MFs of different intensity: 0.10, 0.15, or 0.20 Tesla (T). Each culture vessel at each MF intensity was cultured on the North (N) or South (S) poles of specialised magnets. The 0.15 T MF was also applied for different lengths of time (1, 2, or 3 months) at both the N and S poles. Control plantlets were simply exposed to the naturally-occurring geo-MF, and not to any induced MF. All MFs tested had a positive influence on shoot and root development, but did not influence chlorophyll contents. Among all the intensities and polarities of MF tested, 0.10 T – S had the greatest positive influence on specific growth parameters of Phalaenopsis plantlets such as maximum leaf length, root length, fresh weight and dry weight of shoots and roots, and leaf width. Constant exposure to a MF of 0.15 T for 3 months, at either the N or S poles, significantly enhanced the development of plantlets.The results obtained in this study indicate that MFs can have a positive effect on the efficiency and quality of clonal Phalaenopsis plantlets during commercial production. The MFs from commercially-produced permanent magnets enhanced Phalaenopsis plantlet growth significantly and can be used as a novel means to study the effect of MFs on plant growth and development, or to control morphogenesis in limited spaces such as space stations.