Traits of transgenic Atropa belladonna doubly transformed with different Agrobacterium rhizogenes strains

Hairy root cultures of Atropa belladonna L. were established by infection either with Agrobacterium rhizogenes ATCC 15834 or MAFF 03-01724, and transgenic plants were obtained from both hairy root cultures. Doubly transformed roots were induced by re-infection of the leaf segments of transgenic Atropa belladonna plants (A. rhizogenes 15834) with MAFF 03-01724. Shoots and viviparous leaves were regenerated from the doubly transformed roots. The genetic transformation was determined by the opine assay (agropine, mannopine and/or mikimopine) and polymerase chain reaction. Physiological changes and tropane alkaloid biosynthesis in the hairy roots (singly and doubly transformed) were investigated. The alkaloid content in the doubly transformed root strain was intermediate as compared to the root strains which were singly transformed. On the other hand endogenous IAA levels in doubly transformed roots were significantly decreased compared to both singly transformed roots.Abbreviations BA benzyladenine - IAA indoleacetic acid - NAA naphthaleneacetic acid - PCR polymerase chain reaction - t-ZR trans-zeatin     

Shoaling preference and evidence for maintenance of sibling groups by juvenile black perch Embiotoca jacksoni

Group sizes in free‐living juvenile black perch Embiotoca jacksoni were quantified and predictions of the hypothesis that such groups comprise sibling brood‐mates were tested. Group sizes in the field were within the range of female brood sizes and often occurred close to each other but did not merge. In captivity, juveniles formed groups immediately after birth. In laboratory experiments, they also associated significantly more with chambers containing familiar members of their own brood than empty chambers but did not associate more with chambers containing similar‐sized juveniles from a different brood. Juvenile E. jacksoni also associated significantly more with chambers containing familiar brood‐mates than with chambers containing unfamiliar members of a different brood. The strength of this preference increased with the number of days fish had been together since birth. When two broods were placed in a large outdoor tank, all individuals from both broods directed significantly more aggressive acts towards members of the other brood than towards members of their own brood. While the relative effects of familiarity and relatedness cannot be completely separated in this viviparous species, associating with familiar individuals would facilitate the maintenance of sibling groups in the field.     

Foraging costs drive female resistance to a sensory trap

Male ornaments can evolve through the exploitation of female perceptual biases such as those involved in responding to cues from food. This type of sensory exploitation may lead to confusion between the male signals and the cues that females use to find/recognize food. Such interference would be costly to females and may be one reason why females evolve resistance to the male ornaments. Using a group of species of viviparous fish where resistance to a sensory trap has evolved, we demonstrate that females exposed to an ornament that resembles food have a diminished foraging efficiency, that this effect is apparent when foraging on a food item with which the ornament shares visual attributes, and that not all species are equally affected by such confusion. Our results lend support to the model of ornamental evolution through chase-away sexual conflict.     

Isolation and characterization of 13 microsatellite markers for the viviparous surfperch Ditrema temmincki (Embiotocidae) and cross-species amplification

Thirteen microsatellite loci were isolated from a size-selected genomic library of the surfperch (Ditrema temmincki Bleeker). All loci displayed a high degree of length polymorphism, as observed in the total number of alleles per locus (two to 23) and a high degree of estimated heterozygosity, ranging from 0.080 to 0.893. The primers developed for D. temmincki were also tested for their ability to amplify homologous sequences in D. viride and Neoditrema ransonetii. Distinct differences were observed among three species of surfperches, in both genetic variability and the frequency distribution of the alleles.     

Plasma and ovarian thyroxine levels in relation to sexual maturation and gestation in female Sebastes inermis

Plasma T₄ (L-thyroxine) concentrations in the viviparous rockfish Sebastes inermis showed a peak (119·3±27·8 ng ml⁻¹) during the development of embryos. Ovarian T₄ concentrations increased during vitellogenesis and final maturation and decreased during embryogenesis.However, total T₄ content within the ovary increased continuously up to the larval stages. Plasma oestradiol-17β, (E₂) concentrations peaked at the final maturation stage and then recovered to the level seen during the non-reproductive periods. Plasma testosterone (T) concentrations showed a peak (5·33±1·08 ng ml⁻¹) at the embryo stage and high levels were maintained throughout the gestation period. Plasma T₄ concentrations during the embryo stage and ovarian T₄ content during vitellogenesis were much higher than the levels reported in oviparous fishes. These data suggest that in viviparous rockfish, T₄ may be required for sustaining gestation or embryo development within the maternal body. In addition, the high content of total T₄ in the ovary implies that there probably does exist a maternal-embryo relationship during gestation as well as during vitellogenesis.     

Rodlet cells in the posterior intestine of embryos and neonates of two poeciliid species

Rodlet cells occurred in the posterior intestine of embryos and neonates of the swordtail Xiphophorus nigrensis , its hybrids with Xiphophorus pygmaeus and in the platyfish Xiphophorus maculatus . This is the first observation of these enigmatic cells in a viviparous teleost prior to birth. This finding lends support to the endogenous tenet regarding the origin of this cell.     

Asymmetric paternal effect on offspring size linked to parent‐of‐origin expression of an insulin‐like growth factor

Sexual reproduction brings together reproductive partners whose long‐term interests often differ, raising the possibility of conflict over their reproductive investment. Males that enhance maternal investment in their offspring gain fitness benefits, even if this compromises future reproductive investment by iteroparous females. When the conflict occurs at a genomic level, it may be uncovered by crossing divergent populations, as a mismatch in the coevolved patterns of paternal manipulation and maternal resistance may generate asymmetric embryonic growth. We report such an asymmetry in reciprocal crosses between populations of the fish Girardinichthys multiradiatus. We also show that a fragment of a gene which can influence embryonic growth (Insulin‐Like Growth Factor 2; igf2) exhibits a parent‐of‐origin methylation pattern, where the maternally inherited igf2 allele has much more 5′ cytosine methylation than the paternally inherited allele. Our findings suggest that male manipulation of maternal investment may have evolved in fish, while the parent‐of‐origin methylation pattern appears to be a potential candidate mechanism modulating this antagonistic coevolution process. However, disruption of other coadaptive processes cannot be ruled out, as these can lead to similar effects as conflict.     

The maize viviparous15 locus encodes the molybdopterin synthase small subunit

A new Zea mays viviparous seed mutant, viviparous15 (vp15), was isolated from the UniformMu transposon-tagging population. In addition to precocious germination, vp15 has an early seedling lethal phenotype. Biochemical analysis showed reduced activities of several enzymes that require molybdenum cofactor (MoCo) in vp15 mutant seedlings. Because MoCo is required for abscisic acid (ABA) biosynthesis, the viviparous phenotype is probably caused by ABA deficiency. We cloned the vp15 mutant using a novel high-throughput strategy for analysis of high-copy Mu lines: We used MuTAIL PCR to extract genomic sequences flanking the Mu transposons in the vp15 line. The Mu insertions specific to the vp15 line were identified by in silico subtraction using a database of MuTAIL sequences from 90 UniformMu lines. Annotation of the vp15-specific sequences revealed a Mu insertion in a gene homologous to human MOCS2A, the small subunit of molybdopterin (MPT) synthase. Molecular analysis of two allelic mutations confirmed that Vp15 encodes a plant MPT synthase small subunit (ZmCNX7). Our results, and a related paper reporting the cloning of maize viviparous10, demonstrate robust cloning strategies based on MuTAIL-PCR. The Vp15/CNX7, together with other CNX genes, is expressed in both embryo and endosperm during seed maturation. Expression of Vp15 appears to be regulated independently of MoCo biosynthesis. Comparisons of Vp15 loci in genomes of three cereals and Arabidopsis thaliana identified a conserved sequence element in the 5' untranslated region as well as a micro-synteny among the cereals.