Chromosome inheritance and meiotic stability in allopolyploidBrassica napus

AbstractHomoeologous recombination, aneuploidy, and other genetic changes are common in resynthesized allopolyploid Brassica napus. In contrast, the chromosomes of cultivars have long been considered to be meiotically stable. To gain a better understanding of the underlying mechanisms leading to stabilization in the allopolyploid, the behavior of chromosomes during meiosis can be compared by unambiguous chromosome identification between resynthesized and natural B. napus. Compared with natural B. napus, resynthesized lines show high rates of nonhomologous centromere association, homoeologous recombination leading to translocation, homoeologous chromosome replacement, and association and breakage of 45S rDNA loci. In both natural and resynthesized B. napus, we observed low rates of univalents, A–C bivalents, and early sister chromatid separations. Reciprocal homoeologous chromosome exchanges and double reductions were photographed for the first time in meiotic telophase I. Meiotic errors were non-uniformly distributed across the genome in resynthesized B. napus, and in particular homoeologs sharing synteny along their entire length exhibited multivalents at diakinesis and polysomic inheritance at telophase I. Natural B. napus appeared to resolve meiotic errors mainly by suppressing homoeologous pairing, resolving nonhomologous centromere associations and 45S rDNA associations before diakinesis, and reducing homoeologous cross-overs.

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Variations in Ribosomal RNA Gene Loci in Spider Lily (Lycoris spp.)

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.134.5.567 ◽

2009 ◽

Vol 134 (5) ◽

pp. 567-573 ◽

Cited By ~ 13

Author(s):

Yu-Chu Chang ◽

Chou-Tou Shii ◽

Mei-Chu Chung

Keyword(s):

Ribosomal Rna ◽

Fluorescent In Situ Hybridization ◽

Karyotype Evolution ◽

45S Rdna ◽

Chromosome Identification ◽

Rdna Loci ◽

5S And 45S Rdna ◽

High Degree ◽

Type Chromosome

Lycoris species of the Amaryllidaceae are important ornamental and medicinal plants in Asia. Karyotypes of Lycoris species have been studied extensively since the time when their chromosome numbers were first counted over 80 years ago. Based on karyotype, Lycoris taxa can be classified into the monomorphic A group, dimorphic MT group, and the sterile dikaryotype MT-A group. Numerous reports dealing with karyotype analysis and phylogenetic relationship in the genus Lycoris have been published. However, there are disputes and controversies regarding karyotype evolution resulting from lacking efficient and reliable markers for chromosome identification in the genus Lycoris. In this study, we applied fluorescent in situ hybridization (FISH) to visualize the 5S and 45S rDNA loci on chromosomes as landmarks for chromosome identification in Lycoris taxa. In total, 12 accessions of three karyotype groups, including nine species and three artificial dikaryotype hybrids, were investigated. A high degree of variation in the number and position of 5S and 45S rDNA loci was detected among Lycoris taxa. There were four to 14 FISH signals of 5S rDNAs and two to 12 FISH signals of 45S rDNAs observed in each investigated Lycoris accession. Lycoris accessions with the same karyotype 2n = 22A may have different numbers of rDNA loci, which distributed at different chromosomal positions. In an interspecific hybrid, the number and chromosomal position of both 5S and 45S rDNA loci were either the combinations of those in their parental species or considerably modified. Overlapping FISH signals of 5S and 45S rDNAs were colocalized with a 4′, 6-diamidino-2-phenylindole-positive band at the end of the p-arm on almost every T-type chromosome (but not the A-type chromosomes). Based on the features of T-type chromosomes, the possibility of centromeric fission in karyotypic evolution of Lycoris is discussed.

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A Three-Pool Model Dissecting Readily Releasable Pool Replenishment at the Calyx of Held

Scientific Reports ◽

10.1038/srep09517 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 8

Author(s):

Jun Guo ◽

Jian-long Ge ◽

Mei Hao ◽

Zhi-cheng Sun ◽

Xin-sheng Wu ◽

...

Keyword(s):

Time Course ◽

Current View ◽

Vesicle Recycling ◽

Releasable Pool ◽

Readily Releasable Pool ◽

Central Synapse ◽

Pool Model ◽

Underlying Mechanisms ◽

First Time ◽

Intense Stimulation

Abstract Although vesicle replenishment is critical in maintaining exo-endocytosis recycling, the underlying mechanisms are not well understood. Previous studies have shown that both rapid and slow endocytosis recycle into a very large recycling pool instead of within the readily releasable pool (RRP) and the time course of RRP replenishment is slowed down by more intense stimulation. This finding contradicts the calcium/calmodulin-dependence of RRP replenishment. Here we address this issue and report a three-pool model for RRP replenishment at a central synapse. Both rapid and slow endocytosis provide vesicles to a large reserve pool (RP) ~42.3 times the RRP size. When moving from the RP to the RRP, vesicles entered an intermediate pool (IP) ~2.7 times the RRP size with slow RP-IP kinetics and fast IP-RRP kinetics, which was responsible for the well-established slow and rapid components of RRP replenishment. Depletion of the IP caused the slower RRP replenishment observed after intense stimulation. These results establish, for the first time, a realistic cycling model with all parameters measured, revealing the contribution of each cycling step in synaptic transmission. The results call for modification of the current view of the vesicle recycling steps and their roles.

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Physiological and cognitive consequences of a daily 26 h photoperiod in a primate : exploring the underlying mechanisms of the circadian resonance theory

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1079 ◽

2020 ◽

Vol 287 (1931) ◽

pp. 20201079 ◽

Cited By ~ 1

Author(s):

Clara Hozer ◽

Fabien Pifferi

Keyword(s):

Body Temperature ◽

Cycle Length ◽

Biological Clock ◽

Resonance Theory ◽

Marginal Costs ◽

Natural Photoperiod ◽

Underlying Mechanisms ◽

Energetic Expenditure ◽

First Time ◽

Human Primate

The biological clock expresses circadian rhythms, whose endogenous period (tau) is close to 24 h. Daily resetting of the circadian clock to the 24 h natural photoperiod might induce marginal costs that would accumulate over time and forward affect fitness. It was proposed as the circadian resonance theory. For the first time, we aimed to evaluate these physiological and cognitive costs that would partially explain the mechanisms of the circadian resonance hypothesis. We evaluated the potential costs of imposing a 26 h photoperiodic regimen compared to the classical 24 h entrainment measuring several physiological and cognitive parameters (body temperature, energetic expenditure, oxidative stress, cognitive performances) in males of a non-human primate ( Microcebus murinus ), a nocturnal species whose endogenous period is about 23.5 h. We found significant higher resting body temperature and energy expenditure and lower cognitive performances when the photoperiodic cycle length was 26 h. Together these results suggest that a great deviation of external cycles from tau leads to daily greater energetic expenditure, and lower cognitive capacities. To our knowledge, this study is the first to highlight potential mechanisms of circadian resonance theory.

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Direct Correlations among the Grain Size, Texture, and Indentation Behavior of Nanocrystalline Nickel Coatings

Metals ◽

10.3390/met9020188 ◽

2019 ◽

Vol 9 (2) ◽

pp. 188 ◽

Cited By ~ 3

Author(s):

Lu Feng ◽

Yong-Yue Ren ◽

Yan-heng Zhang ◽

Shibin Wang ◽

Linan Li

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Elastic Modulus ◽

Elastic Anisotropy ◽

Texture Coefficient ◽

Process Conditions ◽

Nickel Coatings ◽

Fundamental Relationship ◽

Underlying Mechanisms ◽

First Time

By using nc-Ni coatings as a model system, systematic experiments were designed to evaluate the interaction between the microstructural and mechanical properties tailored by electrodeposition conditions. A direct correlation between grain size and texture was established for the first time. The grain size of the (111) crystalline plane decreases with the texture coefficient (RTC) regardless of the process conditions, and that of the (220) plane has different trends. Then, a peculiar phenomenon is revealed that the dependence of hardness on grain size is accurately described by the Hall-Petch relationship when changing the temperature or pH, but with different slopes, while it deviates from such a relationship with changing current density, denoting more underlying mechanisms related to texture. Finally, a surprising degree of influence of texture on hardness and elastic modulus is also presented, with the overall trend of hardness increasing with texture; and when the RTC of (111) exceeds 40%, the elastic modulus increases with texture, implying a fundamental relationship between modulus and texture. Texture predominates over the other factors on the elastic modulus, revealing the importance of elastic anisotropy. Significantly, the present work suggests a useful tailoring routine to fabricate high quality nc-Ni coatings with the desired structure and mechanical properties.

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CCL14 serves as a novel prognostic factor and tumor suppressor of HCC by modulating cell cycle and promoting apoptosis

Cell Death and Disease ◽

10.1038/s41419-019-1966-6 ◽

2019 ◽

Vol 10 (11) ◽

Cited By ~ 6

Author(s):

Mengxuan Zhu ◽

Weiyue Xu ◽

Chuanyuan Wei ◽

Jing Huang ◽

Jietian Xu ◽

...

Keyword(s):

Prognostic Factor ◽

Tumor Suppressor ◽

Xenograft Tumor ◽

Tumor Tissues ◽

Cc Chemokines ◽

Underlying Mechanisms ◽

First Time ◽

Growth Of Tumor

Abstract CCL14 is a member of CC chemokines and its role in hepatocellular carcinoma (HCC) is still unknown. In this study, CCL14 expression were analyzed by tissue microarray (TMA) including 171 paired tumor and peritumor tissues of patients from Zhongshan Hospital of Fudan University. We found for the first time that CCL14 was downregulated in HCC tumor tissues compared with peritumor tissues (P = 0.01). Meanwhile, CCL14 low expression in HCC tumor tissues is associated with a poor prognosis (P = 0.035). CCL14 also displayed its predictive value in high differentiation (P = 0.026), liver cirrhosis (P = 0.003), and no tumor capsule (P = 0.024) subgroups. The underlying mechanisms were further investigated in HCC cell lines by CCL14 overexpression and knock-down in vitro. We found overexpression of CCL14 suppressed proliferation and promoted apoptosis of HCC cells. Finally, the effect was confirmed by animal xenograft tumor models in vivo. The results shown overexpression of CCL14 lead to inhibiting the growth of tumor in nude mice. Interestingly, our data also implied that CCL14 played these effects by inhibiting the activation of Wnt/β-catenin pathway. These findings suggest CCL14 is a novel prognostic factor of HCC and serve as a tumor suppressor.

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Partial Inhibition of HO-1 Attenuates HMP-Induced Hepatic Regeneration against Liver Injury in Rats

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/9108483 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Ning He ◽

Jun-Jun Jia ◽

Hai-Yang Xie ◽

Jian-Hui Li ◽

Yong He ◽

...

Keyword(s):

Protein Level ◽

Liver Graft ◽

Hepatocyte Proliferation ◽

Hepatic Regeneration ◽

Significant Elevation ◽

Hypothermic Machine Perfusion ◽

Underlying Mechanisms ◽

First Time

We found better liver graft regeneration with hypothermic machine perfusion (HMP) compared with static cold storage (SCS) for the first time in our pilot study, but the underlying mechanisms are unknown. Upregulated heme oxygenase- (HO-) 1 expression has been reported to play a pivotal role in promoting hepatocyte proliferation. Here, we evaluated the novel role of HO-1 in liver graft protection by HMP. Rats with a heterozygous knockout of HO-1 (HO-1+/−) were generated and subjected to 3 h of SCS or HMP pre-half-size liver transplantation (HSLT) in vivo or 6 h of SCS or HMP in vitro; control rats were subjected to the same conditions (HO-1+/+). We found that HSLT induced significant elevation of the HO-1 protein level in the regenerated liver and that HO-1 haplodeficiency resulted in decreased proliferation post-HSLT. Compared with SCS, HMP induced significant elevation of the HO-1 protein level along with better liver recovery, both of which were reduced by HO-1 haplodeficiency. HO-1 haplodeficiency-induced decreased proliferation was responsible for the attenuated regenerative ability of HMP. Mechanistically, HO-1 haploinsufficiency resulted in suppression of hepatocyte growth factor (HGF)/Akt activity. Our results suggest that inhibition of HO-1 mitigates HMP-induced liver recovery effects related to proliferation, in part, by downregulating the HGF-Akt axis.

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A status of guinea fowl (Numida meleagris) and pheasant (Phasianus colchicus) population transferred from wildlife to the breeding assessed based on the histone H1.c’ polymorphic variation

Avian Biology Research ◽

10.1177/1758155919860351 ◽

2019 ◽

Vol 12 (4) ◽

pp. 145-151 ◽

Cited By ~ 1

Author(s):

Andrzej Kowalski

Keyword(s):

Genetic Drift ◽

Phenotypic Diversity ◽

Histone H1 ◽

Guinea Fowl ◽

Negative Effects ◽

Genetic Changes ◽

Numida Meleagris ◽

Hardy Weinberg Equilibrium ◽

First Time ◽

Heterozygous Phenotype

The genetic changes accompanying a relocation of population to the captivity are mostly adverse and usually associated with deterioration of its status. These alterations are greater in small populations in which a loss of genetic variation limits the capability to adaptation. In this work, a status of small-sized guinea fowl and pheasant population relocated to the breeding is presented. These populations were analyzed based on the polymorphism of histone H1.c’, the protein for the first time identified as a heterogeneous. Histone H1.c’ was resolved in the two-dimensional polyacrylamide gel into the isoform H1.c’1 and H1.c’2, so its heterogeneity corresponds to the presence of homozygous phenotypes c’1 and c’2. Because no histone H1.c’ heterozygous phenotype was found, a significant phenotypic diversity in the guinea fowl ( P = 0.023) and pheasant ( P = 0.018) population was detected, together with its departures from Hardy-Weinberg equilibrium ( P < 0.0001). Both populations characterize an extreme loss of genetic diversity due to complete inbreeding ( F = 1) and an impact of genetic drift which, according to the expected values for guinea fowl (0.192) and pheasant (0.182) population, may strongly diminish allele frequency in the following generations. Thus, condition of populations evaluated based on the histone H1.c’ polymorphic variants, recognized as reasonable informative genetic markers (polymorphism information content of guinea fowl = 0.4 and pheasant = 0.38), corresponds to reduction of genetic variability caused by inbreeding and genetic drift. Therefore, it seems that rearing in the captivity can bring negative effects that favor restriction of animals’ vitality and survival of the population.

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Profiling the unique protective properties of intracranial arterial endothelial cells

Acta Neuropathologica Communications ◽

10.1186/s40478-019-0805-4 ◽

2019 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Dorien M. A. Hermkens ◽

Olga C. G. Stam ◽

Nienke M. de Wit ◽

Ruud D. Fontijn ◽

Aldo Jongejan ◽

...

Keyword(s):

Endothelial Cells ◽

Vascular Cognitive Impairment ◽

Molecular Signature ◽

Plaque Development ◽

Gated Channel ◽

Endothelial Genes ◽

Underlying Mechanisms ◽

First Time ◽

Laser Capture ◽

Arterial Endothelial Cells

Abstract Cardiovascular disorders, like atherosclerosis and hypertension, are increasingly known to be associated with vascular cognitive impairment (VCI). In particular, intracranial atherosclerosis is one of the main causes of VCI, although plaque development occurs later in time and is structurally different compared to atherosclerosis in extracranial arteries. Recent data suggest that endothelial cells (ECs) that line the intracranial arteries may exert anti-atherosclerotic effects due to yet unidentified pathways. To gain insights into underlying mechanisms, we isolated post-mortem endothelial cells from both the intracranial basilar artery (BA) and the extracranial common carotid artery (CCA) from the same individual (total of 15 individuals) with laser capture microdissection. RNA sequencing revealed a distinct molecular signature of the two endothelial cell populations of which the most prominent ones were validated by means of qPCR. Our data reveal for the first time that intracranial artery ECs exert an immune quiescent phenotype. Secondly, genes known to be involved in the response of ECs to damage (inflammation, differentiation, adhesion, proliferation, permeability and oxidative stress) are differentially expressed in intracranial ECs compared to extracranial ECs. Finally, Desmoplakin (DSP) and Hop Homeobox (HOPX), two genes expressed at a higher level in intracranial ECs, and Sodium Voltage-Gated Channel Beta Subunit 3 (SCN3B), a gene expressed at a lower level in intracranial ECs compared to extracranial ECs, were shown to be responsive to shear stress and/or hypoxia. With our data we present a set of intracranial-specific endothelial genes that may contribute to its protective phenotype, thereby supporting proper perfusion and consequently may preserve cognitive function. Deciphering the molecular regulation of the vascular bed in the brain may lead to the identification of novel potential intervention strategies to halt vascular associated disorders, such as atherosclerosis and vascular cognitive dysfunction.

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Chloro- and Dichloro-methylsulfonyl Nitrenes: Spectroscopic Characterization, Photoisomerization, and Thermal Decomposition

Molecules ◽

10.3390/molecules23123312 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3312 ◽

Cited By ~ 1

Author(s):

Yang Yang ◽

Xianxu Chu ◽

Yan Lu ◽

Manabu Abe ◽

Xiaoqing Zeng

Keyword(s):

Uv Light ◽

Spectroscopic Characterization ◽

Nitroso Compounds ◽

Triplet Ground State ◽

Sulfonyl Azides ◽

15N Labeling ◽

Underlying Mechanisms ◽

First Time ◽

State Multiplicity ◽

Calculated Potential Energy

Chloro- and dichloro-methylsulfonyl nitrenes, CH2ClS(O)2N and CHCl2S(O)2N, have been generated from UV laser photolysis (193 and 266 nm) of the corresponding sulfonyl azides CH2ClS(O)2N3 and CHCl2S(O)2N3, respectively. Both nitrenes have been characterized with matrix-isolation IR and EPR spectroscopy in solid N2 (10 K) and glassy toluene (5 K) matrices. Triplet ground-state multiplicity of CH2ClS(O)2N (|D/hc| = 1.57 cm−1 and |E/hc| = 0.0026 cm−1) and CHCl2S(O)2N (|D/hc| = 1.56 cm−1 and |E/hc| = 0.0042 cm−1) has been confirmed. In addition, dichloromethylnitrene CHCl2N (|D/hc| = 1.57 cm−1 and |E/hc| = 0 cm−1), formed from SO2-elimination in CHCl2S(O)2N, has also been identified for the first time. Upon UV light irradiation (365 nm), the two sulfonyl nitrenes R–S(O)2N (R = CH2Cl and CHCl2) undergo concomitant 1,2-R shift to N-sulfonlyamines R–NSO2 and 1,2-oxygen shift to S-nitroso compounds R–S(O)NO, respectively. The identification of these new species with IR spectroscopy is supported by 15N labeling experiments and quantum chemical calculations at the B3LYP/6-311++G(3df,3pd) level. In contrast, the thermally-generated sulfonyl nitrenes CH2ClS(O)2N (600 K) and CHCl2S(O)2N (700 K) dissociate completely in the gas phase, and in both cases, HCN, SO2, HCl, HNSO, and CO form. Additionally, ClCN, OCCl2, HNSO2, •NSO2, and the atmospherically relevant radical •CHCl2 are also identified among the fragmentation products of CHCl2S(O)2N. The underlying mechanisms for the rearrangement and decomposition of CH2ClS(O)2N and CHCl2S(O)2N are discussed based on the experimentally-observed products and the calculated potential energy profile.

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β-Adrenergic receptor stimulation inhibits proarrhythmic alternans in postinfarction border zone cardiomyocytes: a computational analysis

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00094.2017 ◽

2017 ◽

Vol 313 (2) ◽

pp. H338-H353 ◽

Cited By ~ 17

Author(s):

Jakub Tomek ◽

Blanca Rodriguez ◽

Gil Bub ◽

Jordi Heijman

Keyword(s):

Adrenergic Receptor ◽

Border Zone ◽

Adrenergic Stimulation ◽

Cell Coupling ◽

Postmyocardial Infarction ◽

Model Cell ◽

Cycle Lengths ◽

Underlying Mechanisms ◽

First Time

The border zone (BZ) of the viable myocardium adjacent to an infarct undergoes extensive autonomic and electrical remodeling and is prone to repolarization alternans-induced cardiac arrhythmias. BZ remodeling processes may promote or inhibit Ca2+ and/or repolarization alternans and may differentially affect ventricular arrhythmogenesis. Here, we used a detailed computational model of the canine ventricular cardiomyocyte to study the determinants of alternans in the BZ and their regulation by β-adrenergic receptor (β-AR) stimulation. The BZ model developed Ca2+ transient alternans at slower pacing cycle lengths than the control model, suggesting that the BZ may promote spatially heterogeneous alternans formation in an infarcted heart. β-AR stimulation abolished alternans. By evaluating all combinations of downstream β-AR stimulation targets, we identified both direct (via ryanodine receptor channels) and indirect [via sarcoplasmic reticulum (SR) Ca2+ load] modulation of SR Ca2+ release as critical determinants of Ca2+ transient alternans. These findings were confirmed in a human ventricular cardiomyocyte model. Cell-to-cell coupling indirectly modulated the likelihood of alternans by affecting the action potential upstroke, reducing the trigger for SR Ca2+ release in one-dimensional strand simulations. However, β-AR stimulation inhibited alternans in both single and multicellular simulations. Taken together, these data highlight a potential antiarrhythmic role of sympathetic hyperinnervation in the BZ by reducing the likelihood of alternans and provide new insights into the underlying mechanisms controlling Ca2+ transient and repolarization alternans. NEW & NOTEWORTHY We integrated, for the first time, postmyocardial infarction electrical and autonomic remodeling in a detailed, validated computer model of β-adrenergic stimulation in ventricular cardiomyocytes. Here, we show that β-adrenergic stimulation inhibits alternans and provide novel insights into underlying mechanisms, adding to a recent controversy about pro-/antiarrhythmic effects of postmyocardial infarction hyperinnervation. Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/%CE%B2-ar-stimulation-and-alternans-in-border-zone-cardiomyocytes/ .

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