Transgenic cotton resistant to herbicide bialaphos

Resistance to bialaphos, a non-selective herbicide, was intro duced into cotton through genetic engineering. A gene encoding phosphinothric in acetyltransferase (bar) from Streptomyces hygroscopicus was inserted into elite varieties of cotton through particle bombardment. Based on the marker gene, -glucuronidase (gus) expression, a total of 18 Pima (Gossypium barbadense), 45 DP50 (G. hirsutum L.), 20 Coker 312 (G. hirsutum) and 2 El Dorado (G. hirsutum) transgenic plants were recovered. Integration of the bar gene into cotton genomic DNA was confirmed by Southern blot analysis and gene expression was confirmed by northern blot and enzyme assays. Herbicide (Basta®) tolerance up to 15 000 ppm was demonstrated in greenhouse trials. The newly introduced herbicide tolerance trait is inherited in a Mendelian fashion in the progenies of germline transformants. This study demonstrates the potential for particle bombardment to introduce commerically important genes directly into elite varieties of cotton. This mode of gene transfer can expedite the introduction of transgenic cotton products into world markets     

Three New “Biological” Species of Tetrahymena (T. hegewischi n. sp., T. sonneborni n. sp., T. nipissingi n. sp.) and Temperature Tolerance of Members of the “pyriformis” Complex1

Stocks of the Tetrahymena pyriformis complex have been collected in North America and their mating reactivity has been studied. In addition to stocks mating with Tetrahymena americanis, T. borealis, T. pigmentosa, T. hyperangularis, and T. australis, stocks belonging to old syngen 5 and three new mating groups, numbers 13, 14, and 15, were discovered. Syngen 5 and groups 13 and 14 are distinct “biological” species, based on their reproductive isolation from other groups and on the ability of withingroup crosses to produce immature progeny. These species have been named T. hegewischi n. sp., T. sonneborni n. sp., and T. nipissingi n. sp., respectively. The cross between the two group 15 stocks did not produce immature progeny, and there is not sufficient evidence to conclude that this pair of stocks represents a separate species. Temperature tolerance measurements have been made on stocks representing all known micronucleate members of “pyriformis” complex. Within each species, the range of temperature tolerances is narrow; the average within-species standard deviation is 0.63°C. The species averages range from 32.7 to 40.7°C. Using syngen numbers, the order from lowest to highest temperature tolerance is 9, 8, 10, 7, 6, 4, 13, 14, 12, 11, 5, 3, 2, 1. The large differences among species make temperature tolerance a useful aid in identification, but the origins of the differences among species are unknown.     

Translocation of carbon and nitrogen from the turbellarian host Amphiscolops langerhansi (Turbellaria: Acoela) to its algal endosymbiont Amphidinium klebsii (Dinophyceae)

The movement of carbon and nitrogen from Amphiscolops langerhansi , fed on ¹⁴C- and ¹⁵N-labelled Tigriopus japonica , to its algal endosymbiont Amphidinium klebsii is examined in a series of experiments designed to detect both sources in the host and utilization by the symbiont. Data for carbon indicate that.1. klebsii utilizes host carbon primarily as respired CO₂ taken up in photosynthesis. Data for nitrogen suggest that translocation takes place primarily through the excretion of ammonia, and that uptake and incorporation by the alga is light-dependent.     

Immunologic Analysis by Gel Diffusion of Effects of Prolonged Cultivation on Histomonas meleagridis (Smith)*

SYNOPSIS. Antigens were prepared from each of 4 lines of Histomonas meleagridis: Hm-L1, a strain highly virulent for both turkeys and chickens; Hm-L1 /C12, Hm-L1 /C24, Hm-L1 /C52, 3 avirulent substrains derived from Hm-L1 after 12, 24, 52 weeks of in vitro cultivation, respectively. Hm-L1 strain and the 3 substrains were maintained in liquid nitrogen. Antisera were developed in rabbits against Hm-L1 and Hm-L1 /C24 parasites. Both antisera were reacted on gel diffusion plates with homologous and heterologous antigens. Two groups of precipitin lines and/or bands designated arbitrarily as A and B, were observed on the slides. Analysis of these bands revealed the common antigenic composition of the 4 histomonads with respect to some of the group A and group B antigens. The concentrations and numbers of precipitin lines in both groups increased, however, with the length of cultivation. These antigenic differences are discussed in the light of their possible relationship to pathogenicity.     

General Principles of Classification and Nomenclature in Folk Biology

Since about 1954, modern field research has been carried out by a number of ethnographers and biologists in an effort to understand more fully the nature of folk biological classification. Much of this work has been devoted to studies dealing with the naming and classification of plants and animals in non-Western societies. It has now become apparent that several important and far reaching generalizations can be formulated which promise to throw considerable light on prescientific man's understanding of his biological universe.     

Bemisia tabaci （Hemiptera： Aleyrodidae） nymphal feeding in cotton （Gossypium hirsutum） leaves

We used brightfield electron microscopy （BEM）, differential interference contrast microscopy （DICM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and confocal laser scanning microscopy （CLSM） to investigate the stylet pathways of Bemisia tabaci during nymphal feeding behavior in cotton leaves beginning with penetration of the abaxial leaf surface and ending with stylets in sieve tubes in phloem tissues. Most nymphal stylets within salivary sheaths penetrating leaf tissues made complex turns and developed more than one salivary sheath branch before ending in sieve tubes. The external morphology of the salivary sheaths and their routes between and through leaf cells are described during the present study. Results showed the presence of the stylet within the sieve tubes. B. tabaci nymphs may remove stylets and feed in different sieve tubes. Ten short movies showing the progression of the stylet penetrations from adaxial surface to the sieve tubes are attached to Figures 8-15. The report and movies can be viewed from the internet. Download the movies to a local drive in your computer first for fast upload. The movies are posted on the website http：//www.ars.usda.gov/Services/docs.htm？docid=14629. The movies can be used as a teaching aid in biology classes.     

Biogeography meets conservation: the genetic structure of the endangered lycaenid butterfly Lycaena helle (Denis & Schiffermüller, 1775)

Cold‐adapted species are thought to have had their largest distribution ranges in central Europe during the glacial periods. Postglacial warming caused severe range shifts of such taxa into higher latitudes and altitudes. We selected the boreomontane butterfly Lycaena helle (Denis & Schiffermüller, 1775) as an example to demonstrate the genetic effects of range changes, and to document the recent status of highly fragmented remnant populations. We analysed five polymorphic microsatellite loci in 1059 individuals sampled at 50 different localities scattered over the European distribution area of the species. Genetic differentiation was strong among the mountain ranges of western Europe, but we did not detect similarly distinct genetic groups following a geographical pattern in the more eastern areas. The Fennoscandian populations form a separate genetic group, and provide evidence for a colonization from southern Finland via northern Scandinavia to south‐central Sweden. Species distribution modelling suggests a large extension of the spatial distribution during the last glacial maximum, but highlights strong retractions to a few mountain areas under current conditions. These findings, combined with our genetic data, suggest a more or less continuous distribution of L. helle throughout central Europe at the end of the last ice age. As a consequence of postglacial warming, the species retreated northwards to Fennoscandia and escaped increasing temperatures through altitudinal shifts. Therefore, the species is today restricted to population remnants located at the mountain tops of western Europe, genetically isolated from each other, and evolved into genetically unique entities. Rising temperatures and advancing habitat destruction threaten this wealth of biodiversity. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 155–168.