Decreased preference and reproduction, and increased mortality of Frankliniella occidentalis on thrips-resistant pepper plants

The effect of thrips resistance in pepper (Capsicum annuum L.) – previously shown to result in impeded thrips population development (Maris PC, Joosten NN, Goldbach RW & Peters D (2003a) Restricted spread of Tomato spotted wilt virus in thrips‐resistant pepper. Phytopathology 93: 1223–1227. Maris PC, Joosten NN, Goldbach RW & Peters D (2003b) Spread of Tomato spotted wilt virus and population development of Frankliniella occidentalis in pepper resistant to thrips. Proceedings of the Section Experimental and Applied Entomology Netherlands Entomological Society (NEV) Amsterdam 14: 95–101.) – on thrips’[Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)] reproduction, mortality, host preference, and behaviour was investigated. Reproduction, studied by oviposition and larval survival, was negatively affected by the thrips‐resistant (TR) phenotype, whereas the offspring's developmental rate did not differ on TR and the thrips‐susceptible (TS) phenotype. While thrips’ behaviour was hardly affected by thrips resistance, a significant preference for TS plants over the TR plants was found in different tests. When released on either a TR or a TS plant, thrips dispersed at significantly higher rates from the TR plants, demonstrating that not only an impeded reproduction, but also a reduced residence time adds to the reported lower thrips numbers on TR plants.     

On-line state recognition in a yeast fed-batch culture using error vectors

The physiological states with respect to cell growth and ethanol production in a yeast fed-batch culture expressed in linguistic form could be recognized on-line by fuzzy inferencing based on error vectors. The error vector was newly defined here in a macroscopic elemental balance equation. The physiological states for cell growth and ethanol production were characterized by error vectors using many experimental data from fed-batch cultures. Fuzzy membership functions were constructed from the frequency distributions of the error vectors and state recognition was performed by fuzzy inferencing. In particular, an unusual physiological state for a yeast cultivation, in which aerobic ethanol production was accompanied by very low cell growth, could be recognized accurately. According to the results of the state recognition, an energy parameter, the P/O ratio in the metabolic reaction model was adaptively estimated, and the cell growth was successfully evaluated with the estimated P/O. (c) 1995 John Wiley & Sons, Inc.     

Transfer and expression of the human multiple drug resistance gene as potential human gene therapy

The human multiple drug resistance (MDR) gene has been used as a model for human gene transfer which could lead to human gene therapy. MDR is a transmembrane protein which pumps a number of toxic substances out of cells including several drugs used in cancer chemotherapy. Normal bone marrow cells express low levels of MDR and are particularly sensitive to the toxic effects of these drugs. There are two general applications of MDR gene therapy: (1) to provide drug-resistance to the marrow of cancer patients receiving chemotherapy, and (2) as a selectable marker which when co-transferred with a non-selectable gene such as the human beta globin gene can be used to enrich the marrow for cells containing both genes. We demonstrate efficient transfer and expression of the human MDR gene in a retroviral vector into live mice and human marrow cells including CD34⁺ cells isolated from marrow and containing the bulk of human hematopoietic progenitors. MDR gene transduction corrects the sensitivity of CD34⁺ cells to taxol, an MDR drug substrate, and enriches the marrow for MDR-transduced cells. The MDR gene-containing retroviral supernatant used has been shown to be safe and free of replication-competent retrovirus. Because of the safety of the MDR retroviral supernatant, and efficient gene transfer into mouse and human marrow cells, a phase 1 clinical protocol for MDR gene transfer into cancer patients has been approved to evaluate MDR gene transfer and expression in human marrow.     

Rapid micropreps and minipreps of Ti plasmids and binary vectors fromAgrobacterium tumefaciens

A simple and versatile procedure has been developed for the isolation of both large helper/Ti plasmids and binary vectors fromAgrobacterium tumefaciens. Using a slightly modified alkaline lysis protocol, intact plasmid can be recovered from cultures grown in standard micro-centrifuge tubes or culture tubes in sufficient yield and purity to allow for restriction analysis on ethidium bromide stained gels of the >200 kb Ti plasmid DNA. Contamination by chromosomal DNA is minimal and there is thus no need for isopycnic gradient purification. This same procedure can be combined with a high temperature treatment (37°C) and antibiotic selection to generate preparations containing binary vector DNA that are virtually free of interfering Ti plasmid DNA. Restriction patterns produced from these binary vector DNA preparations are unambiguous and therefore preliminary screening by Southern hybridization can be eliminated.     

基因转移与肿瘤基因工程疫苗

综述了近年来有关利用基因转移技术修饰肿瘤细胞制备肿瘤基因工程疫苗的最新研究进展,着重阐述了逆转录病毒载体介导的基因转移及其安全性;归纳了目前可用于肿瘤基因工程疫苗的各种目的基因的特点及作用并对这类肿瘤疫苗制备过程中所存在的问题进行了分析.     

Paraheliotropic leaf movement in Siratro as a protective mechanism against drought-induced damage to primary photosynthetic reactions: damage by excessive light and heat

Damage to primary photosynthetic reactions by drought, excess light and heat in leaves of Macroptilium atropurpureum Dc. cv. Siratro was assessed by measurements of chlorophyll fluorescence emission kinetics at 77 K (-196°C). Paraheliotropic leaf movement protected waterstressed Siratro leaves from damage by excess light (photoinhibition), by heat, and by the interactive effects of excess light and high leaf temperatures. When the leaves were restrained to a horizontal position, photoinhibition occurred and the degree of photoinhibitory damage increased with the time of exposure to high levels of solar radiation. Severe inhibition was followed by leaf death, but leaves gradually recovered from moderate damage. This drought-induced photoinhibitory damage seemed more closely related to low leaf water potential than to low leaf conductance. Exposure to leaf temperatures above 42°C caused damage to the photosynthetic system even in the dark and leaves died at 48°C. Between 42 and 48°C the degree of heat damage increased with the time of exposure, but recovery from moderate heat damage occurred over several days. The threshold temperature for direct heat damage increased with the growth temperature regime, but was unaffected by water-stress history or by current leaf water status. No direct heat damage occurred below 42°C, but in water-stressed plants photoinhibition increased with increasing leaf temperature in the range 31–42°C and with increasing photon flux density up to full sunglight values. Thus, water stress evidently predisposes the photosynthetic system to photoinhibition and high leaf temperature exacerbates this photoinhibitory damage. It seems probable that, under the climatic conditions where Siratro occurs in nature, but in the absence of paraheliotropic leaf movement, photoinhibitory damage would occur more frequently during drought than would direct heat damage.Abbreviations and symbols PFD photon flux area density - PSI, PSII photosyntem I, II - F _M, F _O, F _V maximum, instantaneous, variable fluorescence emission - PLM paraheliotropic leaf movement; all data of parameter of variation are mean ± standard error     

Movement and distribution pattern of the residues of granular insecticides in tropical soil and okra plants

Summary The increased downward mobility of phorate, quinalphos and carbofuran residues was detected in soil with increase in depth of soil column whereas aldicarb was found to remain localised mainly in 0–7.5 cm and 7.5–15.0 cm layers. Persistence of organophosphate insecticides was higher as compared to carbamates in all the soil layers. Residues of all the four insecticides got distributed in all parts of okra plant through uptake but accumulated in higher amounts in fruits only. Contribution No. 312/83 from I.I.H.R. Bangalore (India)