DIFFERENTIATION OF RAT LENS EPITHELIAL CELLS IN TISSUE CULTURE (III) FUNCTIONS IN VITRO OF A TRANSFORMED RAT LENS EPITHELIAL CELL LINE

Epithelial cells isolated from one-day-old rat lens were neoplastically transformed using Rous Sarcoma Virus (Schmidt-Ruppin-D strain) and have been in continuous culture for over 30 months. This cell line displays some of the characteristics of lens epithelial cells, but can be shown to represent a permanent cell line in that it has been transferred more than 50 times and is continuing to grow, while primary lens cell cultures have never survived beyond 8 weeks. The infecting viral genome can be rescued from the cell line upon fusion with uninfected chick embryo cells. It is anticipated that this newly established cell line, designated RLE-R, will be useful in studies on cellular differentiation.     

Toxicological implications of the mixed-function oxidase catalyzed metabolism of carbon disulfide.

The results of these studies have indicated that the decrease in the activity of the hepatic mixed-function oxidase enzyme system and the concentration of cytochrome P-450 seen on incubation of carbon disulfide (CS2) with rat liver microsomes in the presence of NADPH is the result of the binding of the sulfur atom released in the mixed-function oxidase catalyzed metabolism of CS2 to carbonyl sulfide (COS). Moreover, it appears that COS is further metabolized by the mixed-function oxidase enzyme system to CO2 and that, analogous to the metabolism of CS2 to COS, the sulfur atom released in this reaction also binds to the microsomes and inhibits benzphetamine metabolism and decreases the concentration of cytochrome P-450 detectable as its carbon monoxide complex. The results of these studies also suggest that the decrease in the concentration of cytochrome P-450 and the liver damage seen on in vivo administration of CS2 to phenobarbital pretreated rats, is due to the mixed-function oxidase catalyzed release and binding of the sulfur atoms of CS2. The decrease in the concentration of cytochrome P-450 seen on incubation of CS2 with rat liver microsomes in the presence of NADPH does not appear to be the result of destruction of the heme group or its dissociation from the apoenzyme since the total amount of protoheme is unchanged in microsomes which have been incubated with CS2 and NADPH as compared to those not incubated with these compounds.     

Twelve polymorphic microsatellite loci from the Asian citrus psyllid,Diaphorina citri Kuwayama,the vector for citrus greening disease,huanglongbing

Twelve polymorphic microsatellite markers were developed from microsatellite‐enriched DNA libraries and mined from an expressed sequence tags library of Diaphorina citri, the vector of the citrus greening disease (huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed that allelic diversity ranged from three to eight alleles per locus and observed and expected heterozygosities ranged from 0.014 to 0.569 and from 0.052 to 0.653, respectively. These variable microsatellite loci can provide means for assessing overall genetic variation and migration patterns for this agriculturally important pest species. This information can be used to aid in developing successful management strategies.     

Host–pathogen relationship between Salix and Melampsora sheds light on the parentage of some biomass willows

The association between willow ( Salix ) and rust ( Melampsora ) is highly specific. Willows named Salix burjatica , S. dasyclados ( S. × dasyclados ) and S. × calodendron are important in renewable-energy plantations in the UK and western Europe. There has been much controversy over their origin, species status and nomenclature. It has been suggested that they have originated from hybridization between. S. caprea , S. viminalis and S. cinerea . In the present work, 59 willow clones were investigated through morphological examination and detached leaf inoculation using willow differentials, for their association, in southwest England, with M. capraearum and three pathotypes of Melampsora epitea (Me-A, B and C). M. capraearum was found on all clones of S. caprea and its hybrids with S. aurita ; Me-A on all S. viminalis clones; Me-B on wild S. cinerea , S. × calodendron , S. × dasyclados 'De Biardii 445' and S . 'Spaethii'; Me-C on all S. burjatica clones and most S. × dasyclados clones. Both M. caprearum and Me-A infected all S. × sericans ( S. caprea × viminalis ) clones and S. × dasyclados 'LA041/03'. We suggest that S. × dasyclados 'LA041/03' should be treated as S. × sericans ( S. caprea × S. viminalis ); S. burjatica , S. dasyclados and S. × dasyclados as synonyms; S. × dasyclados 'De Biardii 445' as S. × calodendron 'De Biardii 445'; and S . 'Spaethii' as S. × calodendron 'Spaethii'.     

A comparison of maternal effects and current environment on vital rates of Aphis nerii, the milkweed–oleander aphid

Abstract.  1. Non-Mendelian maternal effects, the effects of maternal phenotype or environment on offspring phenotype, have been documented in numerous taxa. By affecting offspring vital rates (birth, death, and movement), maternal effects have the potential to influence population dynamics. However, relatively few studies have directly linked maternal phenotype or environment to offspring vital rates. Additionally, even fewer studies have compared the magnitude of across-generation effects (i.e. maternal effects) to within-generation effects.
2. Because of their telescoping generations, aphids can be strongly influenced by maternal effects. The effects of maternal density and maternal host-plant species on offspring survival, fecundity, and alate formation were investigated experimentally in Aphis nerii , the milkweed–oleander aphid.
3. Additionally, the relative strength of maternal effects were compared with those operating within a generation. Therefore, in another set of experiments, the effects of current density and host-plant species (within-generation effects) on aphid vital rates were examined.
4. While maternal effects were present, within-generation effects were much stronger and more strongly influenced aphid vital rates. Within a generation, aphids exhibited density-dependent survival, fecundity, and alate formation and these effects varied among host-plant species.
5. These results indicate that while maternal effects have the potential to affect population dynamics, this potential is not always met. Additionally, the current environment, not the environment of previous generations, more strongly impacts population dynamics.     

Genetic variation in expression of defense phenotype may mediate evolutionary adaptation of Asclepias syriaca to elevated CO2

How species interactions may modify the effects of environmental change on evolutionary adaptation is poorly understood. Elevated CO₂ is known to alter plant–herbivore interactions, but the evolutionary consequences for plant populations have received little attention. We conducted an experiment to determine the effects of elevated CO₂ and herbivory by a specialist insect herbivore (Danaus plexippus) on the expression of constitutive and induced plant defense traits in five genotypes of Asclepias syriaca, and assessed the heritability of these traits. We also examined changes in relative fitness among plant genotypes in response to altered CO₂ and herbivory. The expression of plant defense traits varied significantly among genotypes. Elevated CO₂ increased plant growth and physical defenses (toughness and latex), but decreased investment in chemical defenses (cardenolides). We found no effect of elevated CO₂ on plant induction of cardenolides in response to caterpillar herbivory. Elevated CO₂ decreased the expression of chemical defenses (cardenolides) to a different extent depending on plant genotype. Differential effects of CO₂ on plant defense expression, rather than direct effects on relative fitness, may alter A. syriaca adaptation to changing climate.