Explore the vast range of titles available.

Сonstitutive heterochromatin areas are revealed by differential staining as C-positive chromosomal regions. These C-positive bands may greatly vary by location, size, and nucleotide composition. CBG-banding is the most commonly used method to detect structural heterochromatin in animals. The difficulty in identification of individual chromosomes represents an unresolved problem of this method as the body of the chromosome is stained uniformly and does not have banding pattern beyond C-bands. Here, we present the method that we called CDAG for sequential heterochromatin staining after differential GTG-banding. The method uses G-banding followed by heat denaturation in the presence of formamide with consecutive fluorochrome staining. The new technique is valid for the concurrent revealing of heterochromatin position due to differential banding of chromosomes and heterochromatin composition (AT-/GC-rich) in animal karyotyping.

Tandemly arranged and dispersed repetitive DNA sequences are important structural and functional elements that make up a significant portion of vertebrate genomes. Using high throughput, low coverage whole genome sequencing followed by bioinformatics analysis, we have identified seven major tandem repetitive DNAs and two fragments of LTR retrotransposons in the genome of the Nile crocodile (Crocodylus niloticus, 2n = 32). The repeats showed great variability in structure, genomic organization, and chromosomal distribution as revealed by fluorescence in situ hybridization (FISH). We found that centromeric and pericentromeric heterochromatin of C. niloticus is composed of previously described in Crocodylus siamensis CSI-HindIII and CSI-DraI repetitive sequence families, a satellite revealed in Crocodylus porosus, and additionally contains at least three previously unannotated tandem repeats. Both LTR sequences identified here belong to the ERV1 family of endogenous retroviruses. Each pericentromeric region was characterized by a diverse set of repeats, with the exception of chromosome pair 4, in which we found only one type of satellite. Only a few repeats showed non-centromeric signals in addition to their centromeric localization. Mapping of 18S–28S ribosomal RNA genes and telomeric sequences (TTAGGG)n did not demonstrate any co-localization of these sequences with revealed centromeric and pericentromeric heterochromatic blocks.

Bacterial suspensions—a premier example of active fluids—show an unusual response to shear stresses. Instead of increasing the viscosity of the suspending fluid, the emergent collective motions of swimming bacteria can turn a suspension into a superfluid with zero apparent viscosity. Although the existence of active superfluids has been demonstrated in bulk rheological measurements, the microscopic origin and dynamics of such an exotic phase have not been experimentally probed. Here, using high-speed confocal rheometry, we study the dynamics of concentrated bacterial suspensions under simple planar shear. We find that bacterial superfluids under shear exhibit unusual symmetric shear bands, defying the conventional wisdom on shear banding of complex fluids, where the formation of steady shear bands necessarily breaks the symmetry of unsheared samples. We propose a simple hydrodynamic model based on the local stress balance and the ergodic sampling of nonequilibrium shear configurations, which quantitatively describes the observed symmetric shear-banding structure. The model also successfully predicts various interesting features of swarming vortices in stationary bacterial suspensions. Our study provides insights into the physical properties of collective swarming in active fluids and illustrates their profound influences on transport processes.

Bio-banding groups athletes by maturity rather than chronological age, to promote more equitable competition and development opportunities. We investigated whether physical and technical performance differed between chronological and bio-banded 11v11 match-play formats in youth soccer. A secondary aim was to examine whether these differences varied by maturity status and timing. Twelve Junior Premier League teams (N = 139 players) from the U13, U14, and U15 age groups participated. Each team played six, 20-minute matches: three in chronological age and three in bio-banded formats. Bio-banding was based on the percentage of predicted adult height: pre-peak height velocity (<90 %), mid-peak height velocity (90–96 %) and post-peak height velocity (>96 %). Players wore foot-mounted inertial measurement units to record physical (distance covered, high-speed running >4 m/s, sprinting >5.5 m/s, and accelerations/decelerations ±2.6 m/s/s) and technical (total touches, possessions, time on ball and one-touch/short/long possession counts) performance characteristics. Data were analysed using t-tests and analysis of variance with Bonferroni correction. Significance was set at p < 0.05, and effect sizes (Cohen's d) were calculated. A multivariate analysis was also conducted. Whole sample analysis showed significantly more time on the ball per possession (d = 0.17), and fewer one-touch actions (d = 0.25) in bio-banded matches. Post-peak height velocity players covered significantly more high-intensity distance (d = 0.63) but recorded fewer total touches (d = 0.60), total possessions (d = 0.65) and one-touch possessions (d = 0.71) in the bio-banded format. There were significant differences between pre- and mid-peak height velocity players for all physical metrics across both chronological and bio-banded matches (d = 0.48–72), and between maturity groups (pre-post-peak height velocity, mid-post-peak height velocity) for technical actions in chronological format but not mirrored in bio-banding matches. Bio-banding was associated with altered physical and technical demands, especially for post-peak height velocity players. Findings suggest bio-banding may provide an appropriate competition format, exposing players to different developmental challenges, which may support more equitable and balanced experiences.

The current study analyzed the chromosomal karyotype of Quasipaa spinosa David, 1875 from Hunan Province, China. The karyotype, C-banding, BrdU-banding pattern were characterized using direct preparation of bone-marrow cells and hemocyte cultures. The findings indicated that Q. spinosa was a diploid species (2n = 26) that lacked heteromorphic chromosomes and secondary constrictions. C-banding analysis revealed an abundance of positive signals in the centromere regions, while the BrdU-banding pattern showed three phases in both male and female, occurring consistently and in chronological sequence during S-phase. Notably, there was no asynchronous replication in the late phase. This study enhanced our understanding of the karyotypic structure of Q. spinosa by conventional cytogenetic techniques, thus providing essential scientific insights into the cytogenetics of Q. spinosa .

The genus Ctenomys comprises about 70 species with great chromosome diversity. The Corrientes group is one of the most chromosomally variable lineages in the genus, where the diploid number (2n) varies from 41 to 70. In this group, three nominal species and numerous polymorphic and polytypic populations have been described. In order to get insight into the chromosomal evolution of this species complex, we applied different banding and molecular cytogenetic techniques. The results were interpreted in an evolutionary context, based on mitochondrial cytochrome b analyses. Studied samples are representative of the broad chromosomal variability in the group, including specimens with 2n = 42 to 2n = 70. Heterochromatin was scarce but concentrated in a few chromosomes. Centromeric DAPI-negative heterochromatin was observed in some autosomal pairs, which differed among populations. Location and amount of DAPI-neutral heterochromatin within the Y chromosome varied among populations. The variable distribution of heterochromatin indicates its dynamic behavior. NORs were detected in one pair of autosomes, which also differed among some populations. Telomeric FISH signals were observed in all complements only at the chromosome ends. The Corrientes group belongs to a clade that also includes C. pearsoni, C. lami, C. minutus, C. ibicuiensis and C. torquatus. Almost all of these species are variable at the chromosomal level, suggesting that this is the ancestral condition of the clade. Within the Corrientes group, the observed low genetic divergence, in contrast with its high chromosomal variability, is indicative of decoupling between the rates of chromosomal and mitochondrial evolution.

Objective This retrospective cytogenetic analysis aimed to characterize karyotypic profiles in a cohort of infertile Han Chinese couples undergoing assisted reproductive technology (ART) interventions. Methods G-banding karyotyping analysis was performed in 62,587 infertile couples from the outpatient department of the Institute of Women, Children and Reproductive Health, Shandong University (N-banding and C-banding technique or high-resolution technique if necessary) between January 2013 and December 2022. Results The overall prevalence of chromosomal abnormalities was 2.35% (2,938/125,174), with 2.04% (1,276/62,587) occurring in women and 2.66% (1,662/62,587) in men. Reciprocal translocation emerged as the predominant form of chromosomal abnormalities in the infertility population, followed closely by mosaicism. In the category of chromosomal polymorphisms, autosomal variations were identified in 8,372 cases, while sex chromosome variations were noted in 920 cases. The most frequently observed polymorphisms included 1qh+, 9qh+, 16qh+, and Yqh+ (add of the secondary constriction). The total incidence of chromosomal variations, including both abnormalities and polymorphisms, was significantly higher in males than in females, with a statistically significant difference ( P  < 0.001). Conclusions Chromosomal variations are acknowledged as significant contributors to infertility, and infertile men possess an increased risk of chromosomal abnormalities or polymorphisms. Routine cytogenetic analysis, therefore, is strongly recommended for infertile couples undergoing ART for the most suitable treatment.

Introduction: The maturation process in young athletes has been widely studied due to its influence on sports performance and training responses. In endurance sports such as triathlon, understanding biological development is crucial for guiding athlete development and competition structuring. Objective: The aim of this study was to investigate the correlation between biological age and chronological age, assess variations in maturity status within age groups, and determine whether bio-banding should be recommended for youth and junior triathlon. Methodology: A cross-sectional study was conducted with 296 young triathletes of both sexes who participated in national, state, or regional multi-sport events in Brazil between 2022 and 2023. Biological maturity status was estimated using the percentage of predicted adult height (%PAH) and predicted age at peak height velocity (APHV). Results: A strong correlation was observed between chronological age and biological age, suggesting that most young triathletes developed within expected standards. Both indicators were considered good estimators of maturity, although the predicted age at peak height velocity appeared to better reflect intra-group variation. The results are consistent with previous studies that support the use of non-invasive maturity indicators in youth sports. The application of these indicators contributes to a more equitable interpretation of performance and training potential across maturity stages. Conclusions: It is concluded that age grouping remains an appropriate method for organizing youth triathlon competitions. However, bio-banding emerges as a strategic alternative for planning training and guiding talent identification, considering biological maturity and its influence on performance. Introducción: El triatlón juvenil y junior presenta desafíos en la agrupación de atletas debido a las diferencias en la madurez biológica. El bio-banding ha sido propuesto como estrategia para mejorar la equidad en la competición, aunque su aplicación en este deporte aún es limitada. Objetivos: Investigar la correlación entre la edad biológica y la edad cronológica, evaluar las variaciones en el estado de madurez dentro de los grupos de edad y determinar si se debe recomendar el bio-banding para competiciones de triatlón juvenil y junior. Metodología: Participaron 296 jóvenes triatletas de ambos sexos que compitieron en eventos multideportivos en Brasil entre 2022 y 2023. El estado de madurez biológica se determinó mediante el porcentaje de madurez biológica prevista (%PAH) y la edad prevista a la velocidad máxima de altura (APHV). Resultados: Se encontró una fuerte correlación entre %PAH y APHV, indicando que la mayoría de los triatletas se desarrollan dentro del rango esperado. Ambos indicadores se consideraron buenos estimadores de madurez, siendo el APHV el que reflejó con mayor precisión las variaciones en las etapas de madurez. Conclusiones: La agrupación por edades se confirmó como una estrategia eficaz para organizar competiciones de triatlón. El bio-banding se presenta como una alternativa viable para diseñar planes de entrenamiento y orientar la selección y desarrollo de jóvenes triatletas, considerando su madurez y relación con el rendimiento competitivo. Sin embargo, debido a la naturaleza transversal del estudio, existen limitaciones para comprender completamente el desarrollo longitudinal de los atletas. Introdução: O triatlo juvenil e júnior apresenta desafios no agrupamento de atletas devido às diferenças na maturidade biológica. A bioanilhagem foi proposta como uma estratégia para melhorar a justiça nas competições, embora a sua aplicação neste desporto seja ainda limitada.Objectivos: Investigar a correlação entre a idade biológica e a idade cronológica, avaliar as variações no estado de maturidade dentro dos grupos etários e determinar se a biobandagem deve ser recomendada para competições de triatlo juvenil e júnior.Metodologia: Participaram 296 jovens triatletas de ambos os sexos que competiram em eventos multidesportivos no Brasil entre 2022 e 2023. O estado de maturidade biológica foi determinado pela percentagem de maturidade biológica prevista (%PAH) e pela idade prevista na velocidade de pico de altitude (APHV).Resultados: Foi encontrada uma forte correlação entre a %PAH e o APHV, indicando que a maioria dos triatletas se desenvolve dentro do intervalo esperado. Ambos os indicadores foram considerados bons estimadores de maturidade, sendo que o APHV reflete com maior precisão as variações dos estádios de maturidade.Conclusões: A segmentação por idades confirmou-se como uma estratégia eficaz para a organização de provas de triatlo. A biobandagem apresenta-se como uma alternativa viável para a elaboração de planos de treino e direcionamento da seleção e desenvolvimento de jovens triatletas, considerando a sua maturidade e relação com o desempenho competitivo. No entanto, devido à natureza transversal do estudo, existem limitações para compreender completamente o desenvolvimento longitudinal dos atletas.

Bacterial chromosomes are folded to compact DNA and facilitate cellular processes. Studying model bacteria has revealed aspects of chromosome folding that are applicable to many species. Primarily controlled by nucleoid-associated proteins, chromosome folding is hierarchical, from large-scale macrodomains to smaller-scale structures that influence DNA transactions, including replication and transcription. Here we review the environmentally regulated, architectural and regulatory roles of nucleoid-associated proteins and the implications for bacterial cell biology. We also highlight similarities and differences in the chromosome folding mechanisms of bacteria and eukaryotes.Advances in sequencing- and imaging-based techniques for chromosome structure analysis have led to a mature understanding of bacterial chromosome structure and dynamics. In this Review, Dame, Rashid and Grainger discuss the hierarchical nature of bacterial chromosome structure and how it is influenced by diverse types of nucleoid-associated proteins. Furthermore, they describe roles for nucleoid-associated proteins and chromosome structure, including in gene expression, chromosome segregation and cell cycle regulation.