Phytophthora antagonism of endophytic bacteria isolated from roots of black pepper (Piper nigrum L.).

[[abstract]]Abstract: In this study, 90 root samples were collected from 30 black pepper farms in three provinces in the Central Highlands of Vietnam. A total of 352 endophytic bacteria were isolated and their morphology described. An in vitro assay on the ntifungal activity of these isolates was then conducted and 47 isolates were found to have antagonistic activity on Phytophthora fungi. The antifungal activity of the 47 isolates was evaluated in vivo by shoot assay. Among these 47 isolates, 6 were selected for further investigation. The six isolates were classified and identified by sequencing the 16S RNA gene and phylogeny. The results showed that all six endophytic bacteria belong to the following species of Bacillus genus: B. siamensis, B. amyloliquefaciens, B. velezenis, and B. methylotrophiycus. Enzymatic activity related to the antifungal activity of the six potent isolates was determined; it showed that they possessed high chitinase and protease activities. These isolates were applied for black pepper seedlings in greenhouse. The results showed three promising isolates: B. siamensis EB.CP6, B. velezensis EB.KN12, and B. methylotrophycus EB.KN13. Black pepper seedlings treated with the promising bacteria had the lowest rate of root disease (8.45–11.21%) and lower fatal rate (11.11–15.55%) compared to the control group (24.81% and 24.44%). In addition, the three promising isolates strongly affected the growth of the black pepper seedlings in greenhouse. The plant height, length of roots, and fresh biomass of the seedlings in the treated plots were higher than those in the control plots. Thus, the endophytic bacterial isolates have the potential to act as biocontrol agent for the sustainable production of black pepper.[[sponsorship]]科技部[[notice]]補正完

A Component of Retinal Light Adaptation Mediated by the Thyroid Hormone Cascade

Analysis with DNA-microrrays and real time PCR show that several genes involved in the thyroid hormone cascade, such as deiodinase 2 and 3 (Dio2 and Dio3) are differentially regulated by the circadian clock and by changes of the ambient light. The expression level of Dio2 in adult rats (2–3 months of age) kept continuously in darkness is modulated by the circadian clock and is up-regulated by 2 fold at midday. When the diurnal ambient light was on, the expression level of Dio2 increased by 4–8 fold and a consequent increase of the related protein was detected around the nuclei of retinal photoreceptors and of neurons in inner and outer nuclear layers. The expression level of Dio3 had a different temporal pattern and was down-regulated by diurnal light. Our results suggest that DIO2 and DIO3 have a role not only in the developing retina but also in the adult retina and are powerfully regulated by light. As the thyroid hormone is a ligand-inducible transcription factor controlling the expression of several target genes, the transcriptional activation of Dio2 could be a novel genomic component of light adaptation

Introduction: special issue for the selected papers in the fourth international conference on Intelligent Multimedia Computing and Networking (IMMCN) 2005

Department of Computin

ĐA DẠNG DI TRUYỀN CỦA TẬP ĐOÀN GIỐNG XOÀI TẠI VÙNG ĐỒNG BẰNG SÔNG CỬU LONG

 Mango species in theMekong Delta ofViet Nam was considered as in the region of original center of polyembryo mangoes (Vo Cong Thanh andHuynhKy, 2000).  A twelve economic mango varieties propagated by seeds such as ?Cat Chu?, ?Thanh ca?, ?Thom? planting in the region,six mango varieties in the germplasm of Cantho University were also analysed by leaf protein (SDS-PAGE) and DNA (CAPS-PCR run with 5 primer: CAP1A, CAP3A, CAP3B, CAP5A, CAP12A) methods. Results showed that any young leaf samples in the same tree had the same proteins,a sexual plant could distinguish with asexual plants by leaf protein method easily. CAP5A could be applied to distinguish polyembryos into one sexual and asexual embryos.  Mango varieties such as ?Du Du?, ?Thom?, ?Buoi?, and ?Hon? were clasified into the same group (M.odorata).  Other varieties including ?Bac?, ?Cat Chu?, ?Cat?, ?Tuong?, ?Cat Hoa Loc? were M. indica, and  ?Thanh Ca? variety has confirmed as M. mekongensis (Pham Hoang Ho 2001). Đồng Bằng Sông Cửu Long nằm trong vùng khởi nguyên của cây xoài trồng.  Xoài là loại cây ăn trái vừa có phẩm chất ngon, vừa thích hợp với thị hiếu của người tiêu dùng, do đó nó có giá trị cao về mặt kinh tế.  Với kỹ thuật điện di protein (bằng phương pháp SDS-PAGE) và điện di ADN (primer CAP 5A) đã nhận diện được cây lai và cây phôi tâm của 6 giống xoài: Trung Quốc, Martin, Cát Vân Đen, Cát Hòa Lộc, Phim Xẻng Măng, Namdorkmai.  Kết quả điện di protein cũng cho thấy các giống: (1) Giống xoài Bưởi, Đu Đủ, Hòn và Thơm thuộc loài Mangifera odorata;  (2) Giống xoài Cát, Cát Chu, Lai, Cát Hòa Lộc, Tượng và Bắc thuộc loài Mangifera indic;  (3) Giống xoài Thanh Ca thuộc loài Mangifera mekongensis

Honeycomb geometry: Rigid motions on the hexagonal grid

International audienceEuclidean rotations in R^2 are bijective and isometric maps, but they lose generally these properties when digitized in discrete spaces. In particular, the topological and geometrical defects of digitized rigid motions on the square grid have been studied. In this context, the main problem is related to the incompatibility between the square grid and rotations; in general, one has to accept either relatively high loss of information or non-exactness of the applied digitized rigid motion. Motivated by these considerations, we study digitized rigid motions on the hexagonal grid. We establish a framework for studying digitized rigid motions in the hexagonal grid---previously proposed for the square grid and known as neighborhood motion maps. This allows us to study non-injective digitized rigid motions on the hexagonal grid and to compare the loss of information between digitized rigid motions defined on the two grids