Growth and survival of reciprocal crosses between two bay scallops, Argopecten irradians concentricus Say and A-irradians irradians Lamarck

A complete diallel cross between two bay scallop populations, Argopecten irradians concentricus Say (M) and A. irradians irradians Lamarck (C), was carried out. Growth and survival were compared among hybrids and pure populations. No significant difference in the shell length was found among the four groups on the first day of D-larvae. On day 10, shell lengths of the two reciprocal crosses (CM, MC)(female x male ) were significantly greater than those of the CC (141.97 mu m) and MM (146.20 mu m) groups, with the growth rate of the MC (156.14 mu m) cross greater than that of the CM (155.35 mu m) cross. Also, heterosis for survival was significantly larger than that for growth. Both maternal origin and mating strategy had significant effects on growth and survival throughout the whole larval stage. Heterosis was also observed in later spat and adult stages. On day 170, the mean shell length, shell height and total weight of the CM cross were significantly larger than those of the other crosses (P<0.05). The results from this study indicate that hybridization between A. irradians concentricus and A. irradians irradians may be a promising way for genetic improvement of existing bay scallop brood stocks in China. (c) 2007 Elsevier B.V. All rights reserved.

Genetic improvement on Chinese shrimp (Fenneropenaeus chinensis): growth and viability performance in F1 hybrids of different populations

Fenneropenaeus chinensis distributed in the Yellow Sea and Bohai Sea of China and the west coast of the Korean Peninsula. Different geographical populations represent potentially different genetic resources. To learn further the characteristics of different geographical population, crosses among two wild and three farmed populations were produced. The two wild populations were from the Yellow Sea and Bohai Sea (WYP), and the west coast of the Korean Peninsula and coast (WKN). The three farmed populations included the offspring of first generation of wild shrimp from coast in Korea (FKN), the Huang Hai (the Yellow Sea in Chinese) No.1 (HH1), and JK98. The phenotypes growth and survival rates of these populations were compared to confirm the feasibility for crossbreeding. The body length (BL), carapace length (CL), carapace width (CW), height of the second and third abdominal segment (HST), width of the second and third abdominal segment (WST), length of the first abdominal segment (LF), length of the last abdominal segment (LL), live body weight (BW), and survival rate were measured. Different combinations were statistically performed with ANOVA and Duncan's Multiple Range Test. The results show that the survival rate of JK98(a (TM) Euro)xWKN(a (TM),) was the highest, followed by WYP(a (TM) Euro)xWKN(a (TM),), FKN(a (TM) Euro)xWYP(a (TM),), FKN(a (TM) Euro)xHH1(a (TM),) and WYP(a (TM) Euro)xFKN(a (TM),); the body weight of FKN(a (TM) Euro)sxHH1(a (TM),) was the highest, followed by FKN(a (TM) Euro)xWYP(a (TM),), WYP(a (TM) Euro)xWKN(a (TM),), WYP(a (TM) Euro)xFKN(a (TM),) and JK98(a (TM) Euro)xWKN(a (TM),); the total length had the same ranking as the body weight. All growth traits in hybrids JK98(a (TM) Euro)xWKN(a (TM),) were the lowest among all combinations. F1 hybrids had significant difference (P < 0.05) in BL, CL, HST, LL, and BW; and insignificant difference (P > 0.05) in other growth traits and survival rate. The results of Duncan's Multiple Range Test are that BL and CL of JK98(a (TM) Euro)xWKN(a (TM),) were significantly different from the other combinations; HST different from the combination of FKN(a (TM) Euro)xWYP(a (TM),), FKN(a (TM) Euro)xHH1(a (TM),) and WYP(a (TM) Euro)xWKN(a (TM),); and BW different from FKN(a (TM) Euro)xWYP(a (TM),) and FKN(a (TM) Euro)xHH1(a (TM),). As a whole, the results indicate that the FKN(a (TM) Euro)xHH1(a (TM),) was the best combination in all growth traits. Therefore, hybridization can introduce the variation to base populations. The systematic selection program based on additive genetic performance may be more effective than crossbreeding.

Chromosomal mapping of the major ribosomal RNA genes in the dwarf surfclam (Mulinia lateralis Say)

Chromosomal location of the major ribosomal RNA genes (rRNA) were studied in the dwarf surfclam (Mulinia lateralis, Say) using fluorescence in situ hybridization (FISH). FISH probes for the rRNA genes were made by polymerase chain reaction (PCR), labeled with digoxigenin-11-dUTP and detected with fluorescein-labeled antidigoxigenin antibodies. Mulinia lateralis had a diploid number of 38 chromosomes and all chromosomes were telocentric. FISH with the rRNA probe produced positive and consistent signals on two pairs of chromosomes: Chromosome 15 with a relative length of 4.6% and Chromosome 19, the shortest chromosome. Both loci were telomeric. The rRNA location provides the first physical landmark of the M. lateralis genome.

Cytological and Molecular Identification of Alien Chromatin in Giant Spike Wheat Germplasm

Alien chromosomes of twelve giant spike wheat germplasm lines were identified by C-banding, genomic in situ hybridization (GISH), sequence characterized amplified region (SCAR), and random amplified polymorphic DNA (RAPD). All lines showed a chromosome number of 2n = 42, five of them carried both a pair of wheat-rye (Triticum aestivum-Secale cereal) 1BL/1RS translocation chromosomes and a pair of Agropyron intermedium (Ai) chromosomes, three carried a pair of Ai chromosomes only, three others carried a pair of 1BL/1RS chromosomes only, and one carried neither 1BL/1BS nor Ai chromosome. Further identification revealed that the identical Ai chromosome in these germplasm lines substituted the chromosome 2D of common wheat (Triticum aestivum L.), designated as 2Ai. The genetic implication and further utilization of 2Ai in wheat improvement were also discussed.

Radiation and diversification within the Ligularia-Cremanthodium-Parasenecio complex (Asteraceae) triggered by uplift of the Qinghai-Tibetan Plateau

The Ligularia-Cremanthodium-Parasenecio (L-C-P) complex of the Tussilagininae (Asteraceae: Senecioneae) contains more than 200 species that are endemic to the Qinghai-Tibetan Plateau in eastern Asia. These species are morphologically distinct; however, their relationships appear complex. A phylogenetic analysis of members of the complex and selected taxa, of the tribe Senecioneae was conducted using chloroplast (ndhF and trnL-F) and nuclear (ITS) sequences. Phylogenetic trees were constructed from individual and combined datasets of the three different sequences. All analyses suggested that Doronicum, a genus that has been included in the Tussilagininae, should be excluded from this subtribe and placed at the base of the tribe Senecioneae. In addition, the Tussilagininae should be broadly circumscribed to include the Tephroseridinae. Within the expanded Tussilagininae containing all 13 genera occurring in eastern Asia, Tussilago and NSPetasites diverged early as a separate lineage, while the remaining I I genera comprise an expanded L-C-P complex clade. We suggest that the L-C-P clade, which is largely unresolved, most likely originated as a consequence of an explosive radiation. The few monophyletic subclades identified in the L-C-P clade with robust support further suggest that some genera of Tussilagininae from eastern Asia require generic re-circumscriptions given the occurrence of subclades containing species of the same genus in different parts of the phylogentic tree due to homoplasy of important morphological characters used to delimit them. Molecular-clock analyses suggest that the explosive radiation of the L-C-P complex occurred mostly within the last 20 million years, which falls well within the period of recent major uplifts of the Qinghai-Tibetan Plateau between the early Miocene to the Pleistocene. It is proposed that significant increases in geological and ecological diversity that accompanied such uplifting, most likely promoted rapid and continuous allopatric speciation in small and isolated populations, and allowed fixation or acquisition of similar morphological characters within unrelated lineages. This phenomenon, possibly combined with interspecific diploid hybridization because of secondary sympatry during relatively stable stages between different uplifts, could be a major cause of high species diversity in the Qinghai-Tibetan Plateau and adjacent areas of eastern Asia. (c) 2005 Elsevier Inc. All rights reserved.

Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus Rheum (Polygonaceae) inferred from chloroplast DNA trnL-F sequences

Background and Aims Rheum, a highly diversified genus with about 60 species, is mainly confined to the mountainous and desert regions of the Qinghai-Tibetan plateau and adjacent areas. This genus represents a good example of the extensive diversification of the temperate genera in the Qinghai-Tibetan plateau, in which the forces to drive diversification remain unknown. To date, the infrageneric classification of Rheum has been mainly based on morphological characters. However, it may have been subject to convergent evolution under habitat pressure, and the systematic position of some sections are unclear, especially Sect. Globulosa, which has globular inflorescences, and Sect. Nobilia, which has semi-translucent bracts. Recent palynological research has found substantial contradictions between exine patterns and the current classification of Rheum. Two specific objectives of this research were (1) to evaluate possible relationships of some ambiguous sections with a unique morphology, and (2) to examine possible occurrence of the radiative speciation with low genetic divergence across the total genus and the correlation between the extensive diversification time of Rheum and past geographical events, especially the recent large-scale uplifts of the Qinghai-Tibetan Plateau.Methods The chloroplast DNA trnL-F region of 29 individuals representing 26 species of Rheum, belonging to seven out of eight sections, was sequenced and compared. The phylogenetic relationships were further constructed based on the sequences obtained.Key Results Despite the highly diversified morphology, the genetic variation in this DNA fragment is relatively low. The molecular phylogeny is highly inconsistent with gross morphology, pollen exine patterns and traditional classifications, except for identifying all samples of Sect. Palmata, three species of Sect. Spiciformia and a few species of Sect. Rheum as corresponding monophyletic groups. The monotypic Sect. Globulosa showed a tentative position within the clade comprising five species of Sect. Rheum. All of the analyses revealed the paraphyly of R. nobile and R. alexandrae, the only two species of Sect. Nobilia circumscribed by the possession of large bracts. The crude calibration of lineages based on trnL-F sequence differentiation implied an extensive diversification of Rheum within approx. 7 million years.Conclusions Based on these results, it is suggested that the rich geological and ecological diversity caused by the recent large-scale uplifts of the Qinghai-Tibetan Plateau since the late Tertiary, coupled with the oscillating climate of the Quaternary stage, might have promoted rapid speciation in small and isolated populations, as well as allowing the fixation of unique or rare morphological characters in Rheum. Such a rapid radiation, combined with introgressive hybridization and reticulate evolution, may have caused the transfer of cpDNA haplotypes between morphologically dissimilar species, and might account for the inconsistency between morphological classification and molecular phylogeny reported here.

Phylogenetic analyses of Saussurea sect. Pseudoeriocoryne (Asteraceae : Cardueae) based on chloroplast DNA trnL-F sequences

The genus Saussurea is distributed mainly in the temperate and subarctic regions of Eurasia and consists of about 300 species classified into six subgenera and 20 sections. Sect. Pseudoeriocoryne in the subgenus Eriocoryne comprises four species, and is delimited mainly by acaulescence and an inflorescence with congested capitula surrounded by a rosette of leaves. All of these species are endemic to the and Qinghai-Tibet Plateau. Sequences from the chloroplast DNA trnL-F region were obtained for the four species in this section and 26 other species from four subgenera of Saussurea to resolve phylogenetic relationships among these species and to determine whether the shared characters that define sect. Pseudoeriocoryne are synapomorphic or were acquired by convergent evolution. The resulting phylogenies indicated that Saussurea sect. Pseudoeriocoryne as traditionally defined does not constitute a monophyletic group and that each of its species belongs to separate clades. Furthermore, none of these species showed a close relationship with the other species of subgenus Eriocoryne. Our results further indicated that none of the investigated subgenera are monophyletic, and that species from different subgenera clustered together. All these conclusions are provisional and their confirmation would require stronger phylogenetic support. Two possible explanations are suggested for low sequence divergence, poor resolution of internal clades and clustering of species with the rather distinct morphology of Saussurea detected in the present study. The first is rapid radiation and diversification triggered by fast habitat fragmentation due to the recent lifting of the Qinghai-Tibet Plateau and the Quaternary climate oscillations. This could have led to rapid morphological divergence while sequences diverged very little, and also caused the convergent acquisition of similar characteristics in unrelated lineages due to similar selection pressures. The second possible explanation is that both introgressive hybridization and reticulate evolution might have caused the transferring of cpDNA sequences between morphologically dissimilar species, thus leading to homogenization of sequences between lineages. (C) 2004 Elsevier Ltd. All rights reserved.

Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas

Ligularia, a highly diversified genus in the eastern Qinghai-Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2n = 58 and 87. Other species are only diploid, with 2n = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia, are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium, Ligulariopsis, Parasenecio, and Sinacalia. Aneuploid reduction of chromosome number from 2n = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity. (C) 2004 The Linnean Society of London

Nuclear dispositions of subtelomeric and pericentromeric chromosomal domains during meiosis in asynaptic mutants of rye (Secale cereale L.)

EI Mikhailova, SP Sosnikhina, GA Kirillova, OA Tikholiz, VG Smirnov, RN Jones and G Jenkins (2001). Nuclear dispositions of subtelomeric and pericentromeric chromosomal domains during meiosis in asynaptic mutants of rye (Secale cereale L.). Journal of Cell Science, 114 (10), 1875-1882. Sponsorship: Russian Foundation for Basic Research (grants 00-04-48522/ 99-04-48182) RAE2008

„Moja osobista przestrzeń” – prywatne wirtualne kolekcje sztuki

The phenomenon analyzed in the essay My Personal Space – The Private Virtual Collections of Art is the possibility of visiting the world’s museums by means of the Internet – visiting indirect, nevertheless enabling peaceful, profound, multiple and free contemplation of art. The function of Mon espace personnel (My Personal Space) of French museums of Louvre and Orsay that reveals some radical modifications in the perception, understanding and reception of art, is an illustration of this phenomenon. Using Mon espace personnel means traversing the virtual Louvre or Orsay and choosing works of art, their descriptions, analyses, publications etc. and then adding them to the internaut’s personal thematic albums. The phenomenon described is a starting point to the reflection on the significance of the space in which art exists (called, according to Golka, the form of art’s presence) with its ontology as well as its functions and the character of its reception. The identification of what this space is, in the context of the hybridization of the form and the content and the emergence of the computer culture (Manovich) as well as in the context of the popularization of the reality (Krajewski) and the decentralization of the world of art (Wójtowicz), is an important part of this essay. These phenomena are also inscribed in a wider context of the changes of the character, mission and role of the museum in the time of the digital revolution.

Udział miRNA w regulacji alternatywnego splicingu u roślin

Wydział Biologii

W stronę uniwersytetu jako instytucji dobra wspólnego. Filozoficzne podstawy krytycznych badań nad szkolnictwem wyższym

Wydział Nauk Społecznych: Instytut Filozofii

3'-UTR SIRF: A database for identifying clusters of short interspersed repeats in 3' untranslated regions

BACKGROUND:Short (~5 nucleotides) interspersed repeats regulate several aspects of post-transcriptional gene expression. Previously we developed an algorithm (REPFIND) that assigns P-values to all repeated motifs in a given nucleic acid sequence and reliably identifies clusters of short CAC-containing motifs required for mRNA localization in Xenopus oocytes.DESCRIPTION:In order to facilitate the identification of genes possessing clusters of repeats that regulate post-transcriptional aspects of gene expression in mammalian genes, we used REPFIND to create a database of all repeated motifs in the 3' untranslated regions (UTR) of genes from the Mammalian Gene Collection (MGC). The MGC database includes seven vertebrate species: human, cow, rat, mouse and three non-mammalian vertebrate species. A web-based application was developed to search this database of repeated motifs to generate species-specific lists of genes containing specific classes of repeats in their 3'-UTRs. This computational tool is called 3'-UTR SIRF (Short Interspersed Repeat Finder), and it reveals that hundreds of human genes contain an abundance of short CAC-rich and CAG-rich repeats in their 3'-UTRs that are similar to those found in mRNAs localized to the neurites of neurons. We tested four candidate mRNAs for localization in rat hippocampal neurons by in situ hybridization. Our results show that two candidate CAC-rich (Syntaxin 1B and Tubulin beta4) and two candidate CAG-rich (Sec61alpha and Syntaxin 1A) mRNAs are localized to distal neurites, whereas two control mRNAs lacking repeated motifs in their 3'-UTR remain primarily in the cell body.CONCLUSION:Computational data generated with 3'-UTR SIRF indicate that hundreds of mammalian genes have an abundance of short CA-containing motifs that may direct mRNA localization in neurons. In situ hybridization shows that four candidate mRNAs are localized to distal neurites of cultured hippocampal neurons. These data suggest that short CA-containing motifs may be part of a widely utilized genetic code that regulates mRNA localization in vertebrate cells. The use of 3'-UTR SIRF to search for new classes of motifs that regulate other aspects of gene expression should yield important information in future studies addressing cis-regulatory information located in 3'-UTRs.

Spatial Pattern Learning, Catastophic Forgetting and Optimal Rules of Synaptic Transmission

It is a neural network truth universally acknowledged, that the signal transmitted to a target node must be equal to the product of the path signal times a weight. Analysis of catastrophic forgetting by distributed codes leads to the unexpected conclusion that this universal synaptic transmission rule may not be optimal in certain neural networks. The distributed outstar, a network designed to support stable codes with fast or slow learning, generalizes the outstar network for spatial pattern learning. In the outstar, signals from a source node cause weights to learn and recall arbitrary patterns across a target field of nodes. The distributed outstar replaces the outstar source node with a source field, of arbitrarily many nodes, where the activity pattern may be arbitrarily distributed or compressed. Learning proceeds according to a principle of atrophy due to disuse whereby a path weight decreases in joint proportion to the transmittcd path signal and the degree of disuse of the target node. During learning, the total signal to a target node converges toward that node's activity level. Weight changes at a node are apportioned according to the distributed pattern of converging signals three types of synaptic transmission, a product rule, a capacity rule, and a threshold rule, are examined for this system. The three rules are computationally equivalent when source field activity is maximally compressed, or winner-take-all when source field activity is distributed, catastrophic forgetting may occur. Only the threshold rule solves this problem. Analysis of spatial pattern learning by distributed codes thereby leads to the conjecture that the optimal unit of long-term memory in such a system is a subtractive threshold, rather than a multiplicative weight.

Semiconductor nanowire fabrication via bottom-up & top-down paradigms

Semiconductor nanowires are pseudo 1-D structures where the magnitude of the semiconducting material is confined to a length of less than 100 nm in two dimensions. Semiconductor nanowires have a vast range of potential applications, including electronic (logic devices, diodes), photonic (laser, photodetector), biological (sensors, drug delivery), energy (batteries, solar cells, thermoelectric generators), and magnetic (spintronic, memory) devices. Semiconductor nanowires can be fabricated by a range of methods which can be categorised into one of two paradigms, bottom-up or top-down. Bottom-up processes can be defined as those where structures are assembled from their sub-components in an additive fashion. Top-down fabrication strategies use sculpting or etching to carve structures from a larger piece of material in a subtractive fashion. This seminar will detail a number of novel routes to fabricate semiconductor nanowires by both bottom-up and top-down paradigms. Firstly, a novel bottom-up route to fabricate Ge nanowires with controlled diameter distributions in the sub-20 nm regime will be described. This route details nanowire synthesis and diameter control in the absence of a foreign seed metal catalyst. Additionally a top-down route to nanowire array fabrication will be detailed outlining the importance of surface chemistry in high-resolution electron beam lithography (EBL) using hydrogen silsesquioxane (HSQ) on Ge and Bi2Se3 surfaces. Finally, a process will be described for the directed self-assembly of a diblock copolymer (PS-b-PDMS) using an EBL defined template. This section will also detail a route toward selective template sidewall wetting of either block in the PS-b-PDMS system, through tailored functionalisation of the template and substrate surfaces.