Tip growth in xylogenic suspension cultures ofZinnia elegans L.: Implications for the relationship between cell shape and secondary-cell-wall pattern in tracheary elements

Summary The relationship between cell expansion, cortical microtubule orientation, and patterned secondary-cell-wall deposition was investigated in xylogenic cell suspension cultures ofZinnia elegans L. The direction of cell expansion in these cultures is pH dependent; cells elongate at pH 5.5–6.0, but expand isodiametrically at pH 6.5–7.0. Contrary to our expectations, indirect immunofluorescence revealed that cortical microtubules are oriented parallel to the long axis in elongating cells. Pulse labeling of the walls of isolated cells with the fluorochrome Tinopal LPW demonstrated that xylogenic Zinnia mesophyll cells elongate by tip growth in culture. These results confirm that cortical microtubules in developing tracheary elements reorient before bundling to form transverse cortical microtubule bands. This rearrangement may allow the secondary cell wall pattern to conform to cell shape, independent of the direction in which the cell was expanding prior to reorientation.Abbreviations CMT cortical microtubules - Mes 2-[N-morpholino]ethanesulfonic acid - TE tracheary element     

Mitochondrial ND5 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy in a Chinese pedigree

Hypertrophic cardiomyopathy is a primary disorder characterized by asymmetric thickening of the septum and left ventricular wall, which affects 1 in 500 individuals in the general population. Mutations in mitochondrial DNA have been found to be one of the most important causes of hypertrophic cardiomyopathy. Here we report the clinical, genetic and molecular characterization of a Han Chinese family with a likely maternally transmitted hypertrophic cardiomyopathy. Four (2 men/2 women) of 5 matrilineal relatives in this 3-generation family exhibited the variable severity and age at onset of 44 to 79years old. Sequence analysis of the entire mitochondrial DNA in this pedigree identified the known homoplasmic ND5 12338T>C variant. This mitochondrial DNA haplogroup belongs to the Eastern Asian F2a. The 12338T>C variant, highly evolutionarily conserved, resulted in the replacement of the translation initiating methionine with a threonine, shortening the ND5 polypeptide by 2 amino acids. The occurrence of ND5 12338T>C variant exclusively in maternal members of this Chinese family suggested that the 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy. Our findings will provide theoretical basis for genetic counseling of maternally inherited hypertrophic cardiomyopathy.     

Effects of 2,6-dichlorobenzonitrile and Tinopal LPW on the structure of the cellulose synthesizing complexes ofVaucheria hamata

Summary The effects of 2,6-dichlorobenzonitrile (DCB, a known inhibitor of cellulose synthesis) and Tinopal LPW (TPL, an agent which disrupts glucan crystallization) on the structure of cellulose synthesizing complexes (terminal complexes, TCs) in the xanthophycean algaVaucheria hamata were investigated. DCB (10 M) inhibits nascent fibril formation from the TC subunit (based on the absence of impressions) although it does not alter the overall shape of the rectangular TC during the short treatment of 20 min. With a prolonged treatment (60 min), the arrangement of TC subunits becomes disordered, and particles generally exhibited as doublets of subunits are released from each other. DCB also interferes with the formation of the overall shape of the TC although it does not disturb the conversion into TC rows of the subunits (the zymogenic precursor of the TC) packed in the globules. A 15 min treatment with TPL (1 mM) destroys the TC integrity by reducing the subunits into small fragments or particulate aggregates. The particulate rows of the TC are interrupted at many points, and fragments and particulate aggregates are dispersed by prolonged treatment (45 min) with TPL. Unlike DCB, TPL inhibits the conversion of globule subunits into TC rows. New insights on the structural characteristics necessary for cellulose microfibril assembly and possible mechanisms for the biogenesis of theVaucheria TC come from these data.Abbreviations DCB 2,6-dichlorobenzonitrile - TPL Tinopal LPW - TC terminal complex     

荧光增白剂Tinopal LPW对蜀柏毒蛾核型多角体病毒增效作用研究

用1%TinopalLPW荧光增白剂作为蜀柏毒蛾核型多角体病毒增效剂对蜀柏毒蛾2龄幼虫进行室内毒力测定,结果表明1%Tinonal LPW对Parocneria orienta NPV有较强的增效作用.使用3.6×1011PIB/hm2+1%TinopalLPW、1.8×1011PIB/hm2+ 1%TinopalLPW、9.0×1010PIB/hm2+1%TinopalLPW和3.6×1011PIB/hm2、1.8×1011PIB/hm2、9.0×1010PIB/hm26种处理对林间越冬代2-3龄幼虫进行超低容量喷雾防治,结果表明除9.0×1010PIB /hm2+1%TinopalLPW 表现出显著的增效作用外,其余剂量有增效作用但不显著.     

荧光增白剂Tinopal LPW对蜀柏毒蛾核型多角体病毒增效作用研究

用1%TinopalLPW荧光增白剂作为蜀柏毒蛾核型多角体病毒增效剂对蜀柏毒蛾2龄幼虫进行室内毒力测定,结果表明1%TinonalLPW对ParocneriaorientaNPV有较强的增效作用。使用3.6×1011PIB/hm2 1%TinopalLPW、1.8×1011PIB/hm2 1%TinopalLPW、9.0×1010PIB/hm2 1%TinopalLPW和3.6×1011PIB/hm2、1.8×1011PIB/hm2、9.0×1010PIB/hm26种处理对林间越冬代2-3龄幼虫进行超低容量喷雾防治,结果表明除9.0×1010PIB/hm2 1%TinopalLPW表现出显著的增效作用外,其余剂量有增效作用但不显著。     

Use of a Stilbene Brightener,Tinopal LPW,as a Radiation Protectant for Steinernema carpocapsae

A stilbene fluorescent brightener, Tinopal LPW, was used as an ultraviolet (UV) protectant for the entomopathogenic nematode Steinernema carpocapsae (All strain). Irradiation of an aqueous suspension of nematodes produced a LC₅₀ in 15.7 minutes under a sunlamp and in 31.7 minutes in direct sunlight. Irradiation by both sunlamp and sunlight of a suspension of nematodes in Tinopal LPW did not reduce their biological activity as measured by their ability to parasitize wax moth larvae after exposure of 8 hours and 4 hours, respectively. Tinopal LPW appeared promising as a radiation protectant.     

Effects of Optical Brighteners Used in Biopesticide Formulations on the Behavior of Pollinators

A patent has been granted for the formulation of baculoviruses with stilbene-derived optical brighteners, a group of compounds that absorb ultraviolet (UV) radiation and emit visible blue wavelengths. These compounds are being extensively tested for control of forest-feeding lepidopterous insects in North America; optical brighteners may thus become a common ingredient in commercial baculovirus formulations in the near future. Many flower species use UV signals to attract insects and to direct them to the nectaries. We examined a possible consequence of field applications of optical brighteners: their effects on the ability of pollinators to find and handle flowers. In field studies carried out in Mexico and the United Kingdom on three different flower species, application of dilute (0.1% or 1%) concentrations of the optical brightener Tinopal CBS reduced recruitment of bees to flowers. Bees that approached flowers were less likely to land and feed on flowers treated with Tinopal than on controls. On one plant species, Trifolium repens, the time taken for bees to handle inflorescences was longer following applications of Tinopal. It seems that this optical brightener may both reduce recruitment of insects to flowers and interfere with their ability to locate rewards. Field-scale applications could reduce pollination of crops, weeds, and wildflowers and adversely affect bee populations. These possibilities should be examined in more detail before widespread applications of these compounds to the environment are made.