Hybridization and recombination in the yeasts Pichia alni, P. bimundalis, P. finlandica, P. glucozyma, P. henricii, P. hostii, P. minuta var. nonfermentans, P. muscicola

A collection of genetic lines in 8 reproductively isolated Pichia species has been created. The above data have permitted realizing intraspecific hybridization and showing normal meiotic segregation of auxotrophic markers.     

Comparative genome mapping among Populus adenopoda, P. alba, P. deltoides, P. euramericana and P. trichocarpa

Among the genus Populus, the sections Populus (white poplar), Aigeiros Duby (black poplar) and Tacamahaca Spach contain many tree species of economical and ecological important properties. Two parental maps for the inter-specific hybrid population of Populus adenopoda × P. alba (two species of Populus section) were constructed based on SSR and SRAP markers by means of a two-way pseudo-test cross mapping strategy. The same set of SSR markers developed from the P. trichocarpa (belonging to Tacamahaca section) genome which were used to construct the maps of P. deltoides and P. euramericana (two species of Aigeiros section) was chosen to analyze the genotype of the experimental population of P. adenopoda × P. alba. Using the mapped SSR markers as allelic bridges, the alignment of the white and black poplar maps to each other and to the P. trichocarpa physical map was conducted. The alignment showed high degree of marker synteny and colinearity and the closer relationship between Aigeiros and Tacamahaca sections than that of Populus and Tacamahaca. Moreover, there was evidence for the chromosomal duplication and inter-chromosomal reorganization involving some poplar linkage groups, suggesting a complicated course of fission or fusion in one of the lineages. A poplar consensus map based on the comparisons could be constructed will be useful in practical applications including marker assisted selection.     

Comparative biology of Portia africana,P. albimana,P. fimbriata,P. labiata,and P. shultzi,araneophagic, web-building jumping spiders (Araneae: Salticidae): Utilisation of webs,predatory versatility,and intraspecific interactions

Abstract

Portia is a behaviourally complex and aberrant salticid genus. The genus is of unusual importance because it is morphologically primitive. Five species were studied in nature (Australia, Kenya, Malaysia, Sri Lanka) and in the laboratory in an effort to clarify the origins of the salticids and of their unique, complex eyes. All the species of Portia studied were both web builders and cursorial. Portia was also an araneophagic web invader, and it was a highly effective predator on diverse types of alien webs. Portia was an aggressive mimic, using a complex repertoire of vibratory behaviour to deceive the host spiders on which it fed. The venom of Portia was unusually potent to other spiders; its easily autotomised legs may have helped Portia escape if attacked by its frequently dangerous prey. Portia was also kleptoparasitic and oophagic when occupying alien webs. P. fimbriata from Queensland, where cursorial salticids were superabundant, used a unique manner of stalking and capturing other salticids. The display repertoires used during intraspecific interactions were complex and varied between species. Both visual (typical of other salticids) and vibratory (typical of other web spiders) displays were used. Portia copulated both on and away from webs and frequently with the female hanging from a dragline. Males cohabited with subadult females on webs, mating after the female matured. Adult and subadult females sometimes used specialised predatory attacks against courting or mating males. Sperm induction in Portia was similar to that in other cursorial spiders. Portia mimicked detritus in shape and colour, and its slow, mechanical locomotion preserved concealment. Portia occasionally used a special defensive behaviour (wild leaping) if disturbed by a potential predator. Two types of webs were spun by all species (Type 1, small resting platforms; Type 2, large prey-capture webs). Two types of egg sacs were made, both of which were highly aberrant for a salticid. Responses of different species and both sexes of Portia were quantitatively compared for different types of prey. Many of the trends in behaviour within the genus, including quantitative differences in predatory behaviour, seemed to be related to differences in the effectiveness of the cryptic morphology of Portia in concealing the spider in its natural habitat (‘effective crypsis’). The results of the study supported, in general, Jackson & Blest’s (1982a) hypothesis of salticid evolution which, in part, proposes that salticid ancestors were web builders with poorly developed vision and that acute vision evolved in conjunction with the ancestral spiders becoming proficient as araneophagic invaders of diverse types of webs.     

P. P. Golikov,Receptor Mechanisms of Antiglucocorticoid Effect at Emergent States,Moscow: Meditsina, 2002, 311 pp.

Russian Journal of Bioorganic Chemistry -     

A comparative cytogenetic analysis of five pine species from North America, Pinus banksiana, P. contorta, P. monticola, P. resinosa, and P. strobus

The genus Pinus comprises more than 100 species, which are widely distributed in the Northern hemisphere. Cytogenetic information on North American pines is very limited despite their economic importance. In the present study, a detailed comparative cytogenetic analysis is presented for five pine species from North America, P. resinosa, P. monticola, P. contorta, P. banksiana, and P. strobus. Morphometric analysis and physical mapping of rDNA probes were performed. The karyotype of P. monticola was considered ancestral with small difference in relative chromosome lengths. P. banksiana, P. contorta, and P. strobus karyotypes were considered semi-asymmetrical and less ancestral type. P. banksiana showed five secondary constrictions, P. strobus six, and P. contorta eight. P. resinosa karyotype was semi-asymmetrical and derived with 14 secondary constrictions identified on eight different chromosomes. Karyological data were consistent with molecular cytogenetic information. A significant association was observed between the number and locations of secondary constrictions and the 18S-5.8S-26S rDNA sites detected using fluorescence in situ hybridization. The two methods were used to establish a reliable comparative karyotype of the selected pines. In general, karyotype and chromosome evolution were not related to genetic relationships among pine species studied.