Meiotic Nuclear Architecture in Distinct Mole Vole Hybrids with Robertsonian Translocations: Chromosome Chains, Stretched Centromeres, and Distorted Recombination

Genome functioning in hybrids faces inconsistency. This mismatch is manifested clearly in meiosis during chromosome synapsis and recombination. Species with chromosomal variability can be a model for exploring genomic battles with high visibility due to the use of advanced immunocytochemical methods. We studied synaptonemal complexes (SC) and prophase I processes in 44-chromosome intraspecific (Ellobius tancrei × E. tancrei) and interspecific (Ellobius talpinus × E. tancrei) hybrid mole voles heterozygous for 10 Robertsonian translocations. The same pachytene failures were found for both types of hybrids. In the intraspecific hybrid, the chains were visible in the pachytene stage, then 10 closed SC trivalents formed in the late pachytene and diplotene stage. In the interspecific hybrid, as a rule, SC trivalents composed the SC chains and rarely could form closed configurations. Metacentrics involved with SC trivalents had stretched centromeres in interspecific hybrids. Linkage between neighboring SC trivalents was maintained by stretched centromeric regions of acrocentrics. This centromeric plasticity in structure and dynamics of SC trivalents was found for the first time. We assume that stretched centromeres were a marker of altered nuclear architecture in heterozygotes due to differences in the ancestral chromosomal territories of the parental species. Restructuring of the intranuclear organization and meiotic disturbances can contribute to the sterility of interspecific hybrids, and lead to the reproductive isolation of studied species.

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Meiotic nuclear architecture in distinct mole vole hybrids with Robertsonian translocations: chromosome chains, stretched centromeres, and distorted recombination

10.1101/2020.09.17.301473 ◽

2020 ◽

Author(s):

Sergey Matveevsky ◽

Artemii Tretiakov ◽

Irina Bakloushinskaya ◽

Anna Kashintsova ◽

Oxana Kolomiets

Keyword(s):

Interspecific Hybrids ◽

Nuclear Architecture ◽

Late Pachytene ◽

Robertsonian Translocations ◽

Prophase I ◽

Chromosome Synapsis ◽

Chromosome Attachment ◽

Mole Vole ◽

Chromosomal Variability ◽

Chromosomal Territories

AbstractGenome functioning in hybrids faces inconsistency. This mismatch is manifested clearly in meiosis during chromosome synapsis and recombination. Species with chromosomal variability can be a model for exploring genomic battles with high visibility due to the use of advanced immunocytochemical methods. We studied synaptonemal complexes (SC) and prophase I processes in 44-chromosome intraspecific (Ellobius tancrei × E. tancrei) and interspecific (Ellobius talpinus × E. tancrei) hybrid mole voles heterozygous for 10 Robertsonian translocations. The same pachytene failures were found for both types of hybrids. In the intraspecific hybrid, the chains were visible in the pachytene stage, then 10 closed SC trivalents formed in the late pachytene and diplotene stage. In the interspecific hybrid, as a rule, SC trivalents composed the SC chains and rarely could form closed configurations. Metacentrics involved with SC trivalents had stretched centromeres in interspecific hybrids. Linkage between neighboring SC trivalents was maintained by stretched centromeric regions of acrocentrics. This centromeric plasticity in structure and dynamics of SC trivalents was found for the first time. We assume that stretched centromeres were a marker of altered nuclear architecture in heterozygotes due to differences in the ancestral chromosomal territories of the parental species. Restructuring of the intranuclear organization and meiotic disturbances can contribute to the sterility of interspecific hybrids, and lead to the reproductive isolation of studied species.Author summaryMeiosis is essential for sexual reproduction to produce haploid gametes. Prophase I represents a crucial meiotic stage because key processes such as chromosomal pairing, synapsis and desynapsis, recombination, and transcriptional silencing occur at this time. Alterations in each of these processes can activate meiotic checkpoints and lead to the elimination of meiocytes. Here we have shown that two groups of experimental hybrids, intraspecific and interspecific—which were heterozygous for 10 identical Robertsonian translocations—had pachytene irregularities and reduced recombination. However, intraspecific and interspecific hybrids exhibited different patterns of synaptonemal complex (SC) trivalent behavior. In the former, open SC trivalents comprised SC chains due to heterosynapsis of short arms of acrocentrics in early and mid-pachytene and were then able to form 2–4 and even 7 and 10 closed SC trivalents in the late pachytene and diplotene stages. In the second mole voles, SC trivalents had stretched centromeres of the metacentrics, and chains of SC trivalents were formed due to stretched centromeres of acrocentrics. Such compounds could not lead to the formation of separate closed SC trivalents. The distant ancestral points of chromosome attachment with a nuclear envelope in the heterozygous nuclei probably lead to stretching of SC trivalents and their centromeric regions, which can be regarded as an indicator of the reorganization of the intranuclear chromatin landscape. These abnormalities, which were revealed in in prophase I, contribute to a decrease the fertility of intraspecific mole voles and promote the sterility of interspecific mole voles.

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Dynamic nanoscale morphology of the ER surveyed by STED microscopy

The Journal of Cell Biology ◽

10.1083/jcb.201809107 ◽

2018 ◽

Vol 218 (1) ◽

pp. 83-96 ◽

Cited By ~ 39

Author(s):

Lena K. Schroeder ◽

Andrew E.S. Barentine ◽

Holly Merta ◽

Sarah Schweighofer ◽

Yongdeng Zhang ◽

...

Keyword(s):

Living Cells ◽

Stimulated Emission ◽

Membrane Structures ◽

Spatiotemporal Resolution ◽

Sted Microscopy ◽

Superresolution Microscopy ◽

Structure And Dynamics ◽

First Time ◽

Nanoscale Dynamics ◽

Conventional Light Microscopy

The endoplasmic reticulum (ER) is composed of interconnected membrane sheets and tubules. Superresolution microscopy recently revealed densely packed, rapidly moving ER tubules mistaken for sheets by conventional light microscopy, highlighting the importance of revisiting classical views of ER structure with high spatiotemporal resolution in living cells. In this study, we use live-cell stimulated emission depletion (STED) microscopy to survey the architecture of the ER at 50-nm resolution. We determine the nanoscale dimensions of ER tubules and sheets for the first time in living cells. We demonstrate that ER sheets contain highly dynamic, subdiffraction-sized holes, which we call nanoholes, that coexist with uniform sheet regions. Reticulon family members localize to curved edges of holes within sheets and are required for their formation. The luminal tether Climp63 and microtubule cytoskeleton modulate their nanoscale dynamics and organization. Thus, by providing the first quantitative analysis of ER membrane structure and dynamics at the nanoscale, our work reveals that the ER in living cells is not limited to uniform sheets and tubules; instead, we suggest the ER contains a continuum of membrane structures that includes dynamic nanoholes in sheets as well as clustered tubules.

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Fauna of gamasina mites (Gamasoidea) of small mammals of a natural region «Samarskaya Luka»

Samara Journal of Science ◽

10.17816/snv20162112 ◽

2016 ◽

Vol 5 (2) ◽

pp. 57-63

Author(s):

Irina Anatol’evna Sorokopud

Keyword(s):

Small Mammals ◽

Water Vole ◽

Separate Species ◽

Natural Region ◽

Mole Vole ◽

Ecological Complex ◽

Tundra Vole ◽

First Time ◽

Samarskaya Luka

Data on fauna of gamasina mites parasitizing on small mammals are provided in article. Data are obtained during long-term monitoring of an ecological complex of small mammals of a natural and territorial complex Samarskaya Luka, which is realized since 1999. Also data on fauna of gamasina mites in 14 years of researches (2000-2003, 2005, 2007-2015 years), including literary data about the gamasina mites of this territory, are generalized and analysed. Specific accessory of 7439 individuals of mites, seven childbirth of three families relating to fifteen types is defined. Parasitizing the gamasina mites on 16 species of small mammals, including groups rodents, soricomorpha, carnivora (least weasel) is established. Domination of separate species of mites is revealed, so to eudominant Laelaps hilaris and Hirstionyssus isabellinus are belong, dominants are - Hirstionyssus ellobii , Haemolaelaps glasgowi , Hyperlaelaps arvalis , L. agilis . Myonyssus rossicus , L. algericus , Haemogamasus ambulans and Hirstionyssus macedonicus were extremely rare species met in single copies. For the first time for this territory types of H. ellobii , L. micromydis , H. ambulans , H. macedonicus are noted. Conclusions on degree of a confinedness of parasites to certain types of hosts are drawn. Monohostal types: L. agilis (the host - a yellow-necked mouse), L. muris (the host - a tundra vole and a water vole), L. micromydis (the host - a small mouse), L. algericus (the host - a house mouse), H. arvalis (the host - a tundra vole and a water vole), H. ellobii (the host - a northern mole vole). Polihostal: H. musculi , L. hilaris , H. isabellinus , H. glasgowi , E. stabularis , H. nidi .

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A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

10.21203/rs.2.11372/v3 ◽

2019 ◽

Author(s):

Warren Williams ◽

Isabelle M Verry ◽

Helal A Ansari ◽

S Wajid Hussain ◽

Ihsan Ullah ◽

...

Keyword(s):

Chromosome Number ◽

White Clover ◽

Interspecific Hybrids ◽

Species Complex ◽

Embryo Rescue ◽

Polyploid Species ◽

Trifolium Ambiguum ◽

Breeding Populations ◽

Fertile Hybrids ◽

First Time

Abstract Background Trifolium ambiguum occurs as a 2x, 4x, 6x polyploid series in W Asia, The 6x form is the most agronomically desirable, having strong rhizomatous spread and drought tolerance. These traits would be potentially very valuable if they could be transferred to white clover (T. repens) which is the most important agronomic clover species. However, to-date, no fertile interspecific hybrids with 6x T. ambiguum are available. Previously, 2x T. occidentale from W Europe has produced synthetic fertile hybrids with both 2x and 4x T. ambiguum and these were inter-fertile with white clover. Here we ask whether 2x T. occidentale can form fertile hybrids with 6x T. ambiguum and act as a genetic bridge to white clover and bring these species together as part of a common gene pool. Results Ten verified F1 (6x T. ambiguum x 2x T. occidentale) hybrids were produced by embryo rescue and seven were studied further. All four investigated for chromosome number were 2n=4x=32 and FISH confirmed the expected 21 T. ambiguum and 8 T. occidentale chromosomes. Hybrid fertility was extremely low but 2n female gametes functioned with white clover pollen to produce seeds. Derived plants were confirmed using FISH and were successfully backcrossed to white clover to produce partially fertile breeding populations. Conclusions Although T. occidentale and 6x T. ambiguum are widely separated by geography and ecological adaptation they have maintained enough genomic affinity to produce partially fertile hybrids. Inter-fertility of the hybrids with allotetraploid T. repens showed that T. occidentale can provide a genetic bridge between 6x T. ambiguum and white clover to produce plants with new phenotypes combining the traits of all three species. Use of this information should enable potentially valuable stress tolerance traits from 6x T. ambiguum to be used in white clover breeding for the first time.

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Gamma-widths, lifetimes and fluctuations in the nuclear quasi-continuum

EPJ Web of Conferences ◽

10.1051/epjconf/201817806001 ◽

2018 ◽

Vol 178 ◽

pp. 06001

Author(s):

M. Guttormsen ◽

A. C. Larsen ◽

J. E. Midtbø ◽

L. Crespo Campo ◽

A. Görgen ◽

...

Keyword(s):

Excited States ◽

Level Density ◽

Strength Function ◽

Reaction Rates ◽

Theoretical Description ◽

Nuclear Level Density ◽

Capture Process ◽

Structure And Dynamics ◽

Continuum Region ◽

First Time

Statistical γ-decay from highly excited states is determined by the nuclear level density (NLD) and the γ-ray strength function (γSF). These average quantities have been measured for several nuclei using the Oslo method. For the first time, we exploit the NLD and γSF to evaluate the γ-width in the energy region below the neutron binding energy, often called the quasi-continuum region. The lifetimes of states in the quasi-continuum are important benchmarks for a theoretical description of nuclear structure and dynamics at high temperature. The lifetimes may also have impact on reaction rates for the rapid neutron-capture process, now demonstrated to take place in neutron star mergers.

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Sizing the role of London dispersion in the dissociation of all-meta tert-butyl hexaphenylethane

Chemical Science ◽

10.1039/c6sc02727j ◽

2017 ◽

Vol 8 (1) ◽

pp. 405-410 ◽

Cited By ~ 49

Author(s):

Sören Rösel ◽

Ciro Balestrieri ◽

Peter R. Schreiner

Keyword(s):

Nmr Spectroscopy ◽

Tert Butyl ◽

Structure And Dynamics ◽

London Dispersion ◽

First Time

The structure and dynamics of enigmatic hexa(3,5-di-tert-butylphenyl)ethane was characterized via NMR spectroscopy for the first time.

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Restoring Fertility for Novel Interspecific Hybrids between Kalanchoe garambiensis and K. nyikae Using Colchicine Treatment

Plants ◽

10.3390/plants10020209 ◽

2021 ◽

Vol 10 (2) ◽

pp. 209

Author(s):

Yi Kuang ◽

Chi-Hsuan Lu ◽

Fu-Chiun Hsu

Keyword(s):

Interspecific Hybrids ◽

Hybrid Sterility ◽

Colchicine Treatment ◽

Tropical Species ◽

Breeding Programs ◽

Apical Buds ◽

Environmental Adaptations ◽

Reciprocal Crossing ◽

Long Stem ◽

First Time

Interspecific hybridization is an effective strategy in Kalanchoe breeding programs for the introduction of new traits. Wild species within the Kalanchoe genus are valuable genetic resources for providing new horticulture traits and to improve environmental adaptations. However, reproductive barriers associated with fertilization and hybrid sterility must be overcome to produce fertile hybrid progenies. To approach the breeding objectives for Kalanchoe cut flower cultivars with long stem traits and adaptation to tropical/subtropical regions, a tropical species endemic to Taiwan, Kalanchoe garambiensis Kudo, was used as a parent to cross with other long stem Kalanchoe species. Reciprocal crossing was effective in overcoming interspecific unilateral incompatibility in our crossed pairs. One superior hybrid, ‘103-1’, produced capsules without seeds by selfing and backcrossing with pollens from either parent. Other than the seedless trait, failure of pollen releasing from anther, pollen aggregation and no pollen germination in ‘103-1’ suggested its F1 sterility. Colchicine treatments on apical buds of ‘103-1’ successfully overcame potential meiotic abnormalities by doubling ploidy. For the first time, fertile interspecific hybrids of K. garambiensis and K. nyikae Engler were generated. The fertile hybrid has further produced progeny populations by crossing with K. nyikae or K. blossfeldiana von Poelln, ‘Ida’.

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Spatially clustered loci with multiple enhancers are frequent targets of HIV-1

10.1101/287896 ◽

2018 ◽

Author(s):

Bojana Lucic ◽

Heng-Chang Chen ◽

Maja Kuzman ◽

Eduard Zorita ◽

Julia Wegner ◽

...

Keyword(s):

T Cells ◽

Transcriptional Activity ◽

Nuclear Periphery ◽

Nuclear Architecture ◽

Gene Clusters ◽

Nuclear Pore ◽

Super Enhancer ◽

First Time ◽

Hiv 1

ABSTRACTHIV-1 recurrently targets active genes that are positioned in the outer shell of the nucleus and integrates in the proximity of the nuclear pore compartment. However, the genomic features of these genes and the relevance of their transcriptional activity for HIV-1 integration have so far remained unclear. Here we show that recurrently targeted genes are delineated with super-enhancer genomic elements and that they cluster in specific spatial compartments of the T cell nucleus. We further show that these gene clusters acquire their location at the nuclear periphery during the activation of T cells. The clustering of these genes along with their transcriptional activity are the major determinants of HIV-1 integration in T cells. Our results show for the first time the relevance of the spatial compartmentalization of the genome for HIV-1 integration, thus further strengthening the role of nuclear architecture in viral infection.

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Long-Term Trends in the Structure and Dynamics of the Fish Communities in Buško Blato Reservoir

Croatian Journal of Fisheries ◽

10.2478/cjf-2020-0007 ◽

2020 ◽

Vol 78 (2) ◽

pp. 69-78

Author(s):

Aldijana Mušović ◽

Rifat Škrijelj ◽

Mahir Gajević ◽

Belma Kalamujić Stroil ◽

Adi Vesnić ◽

...

Keyword(s):

Fish Species ◽

Ecological Factors ◽

Lepomis Gibbosus ◽

Tinca Tinca ◽

Structure And Dynamics ◽

Current State ◽

Long Term Trends ◽

Endemic Fish ◽

First Time

AbstractBuško Blato Reservoir, the third largest hydro accumulation in Europe, is situated in the south-eastern part of the karstic Livanjsko Polje Valley. This aquatic ecosystem is distinguished by a very rich ichthyofauna and the presence of four endemic fish species. Numerous studies focus on ichthyological researches of Buško Blato Reservoir. Its ichthyofauna has been exposed to changes in ecological factors, which in turn reflected on the structure and composition of fish populations. The main objective of this paper was to assess the current state and predict future trends in the ichthyofauna structure and dynamics based on the field data and comprehensive analyses of literature data. The results of the research indicated the presence of 11 fish species from four families, which is the largest number of fish species ever recorded in this ecosystem. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva and Tinca tinca were recorded for the first time in this ecosystem, while some previously recorded species were not found. The results of the analyses clearly indicate the presence of natural interspecific competition and significant level of threats to the endemic fish species caused by human activities.

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Interbase FRET in RNA: from A to Z

Nucleic Acids Research ◽

10.1093/nar/gkz812 ◽

2019 ◽

Vol 47 (19) ◽

pp. 9990-9997 ◽

Cited By ~ 2

Author(s):

Anders F Füchtbauer ◽

Moa S Wranne ◽

Mattias Bood ◽

Erik Weis ◽

Pauline Pfeiffer ◽

...

Keyword(s):

Nucleic Acids ◽

Structural Changes ◽

Average Structure ◽

Structure And Dynamics ◽

Rna Conformation ◽

First Time ◽

Existing Structure ◽

Fret Pair

Abstract Interbase FRET can reveal highly detailed information about distance, orientation and dynamics in nucleic acids, complementing the existing structure and dynamics techniques. We here report the first RNA base analogue FRET pair, consisting of the donor tCO and the non-emissive acceptor tCnitro. The acceptor ribonucleoside is here synthesised and incorporated into RNA for the first time. This FRET pair accurately reports the average structure of A-form RNA, and its utility for probing RNA structural changes is demonstrated by monitoring the transition from A- to Z-form RNA. Finally, the measured FRET data were compared with theoretical FRET patterns obtained from two previously reported Z-RNA PDB structures, to shed new light on this elusive RNA conformation.

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