Purpose:Derivative chromosomes,resulting from complex structural rearrangements,pose significant challenges in prenatal diagnosis due to their unpredictable inheritance patterns and potential phenotypic consequences.T...Purpose:Derivative chromosomes,resulting from complex structural rearrangements,pose significant challenges in prenatal diagnosis due to their unpredictable inheritance patterns and potential phenotypic consequences.This study evaluates the efficacy of multiple genetic technologies-including karyotyping,fluorescence in situ hybridization(FISH),chromosomal microarray analysis(CMA),and next-generation sequencing(NGS)-in detecting and characterizing derivative chromosomes in prenatal samples.methodology:We analyzed 150 cases of suspected chromosomal abnormalities,comparing detection rates,resolution,and clinical utility across these methods.Results:Our findings demonstrate that integrated multi-technology approaches significantly improve diagnostic accuracy,with NGS-based structural variation analysis achieving the highest detection sensitivity(99.2%)for cryptic rearrangements.Conclusions:Additionally,long-read sequencing(PacBio/Oxford Nanopore)enabled precise breakpoint mapping in 92%of cases,facilitating more accurate genetic counseling.Clinically,this approach enhances risk assessment for fetal anomalies,guides pregnancy management,and improves parental counseling for recurrence risks.展开更多
The objective of this study is to quantitatively reveal the main genetic carrier of antibiotic resistance genes(ARGs)for blocking their environmental dissemination.The distribution of ARGs in chromosomes,plasmids,and ...The objective of this study is to quantitatively reveal the main genetic carrier of antibiotic resistance genes(ARGs)for blocking their environmental dissemination.The distribution of ARGs in chromosomes,plasmids,and phages for understanding their respective contributions to the development of antimicrobial resistance in aerobic biofilm consortium under increasing stresses of oxytetracycline,streptomycin,and tigecyclinewere revealed based on metagenomics analysis.Results showed that the plasmids harbored 49.2%-83.9%of resistomes,which was higher(p<0.001)than chromosomes(2.0%-35.6%),and no ARGs were detected in phage contigs under the strict alignment standard of over 80%identity used in this study.Plasmids and chromosomes tended to encode different types of ARGs,whose abundances all increased with the hike of antibiotic concentrations,and the variety of ARGs encoded by plasmids(14 types and 64 subtypes)was higher than that(11 types and 27 subtypes)of chromosomes.The dosing of the three antibiotics facilitated the transposition and recombination of ARGs on plasmids,mediated by transposable and integrable transfer elements,which increased the co-occurrence of associated and unassociated ARGs.The results quantitatively proved that plasmids dominate the proliferation of ARGs in aerobic biofilm driven by antibiotic selection,which should be a key target for blocking ARG dissemination.展开更多
The stability and evolution of human genetics depend on chromosomes and chromosome-chromosome interactions.We wish to understand the spatial location of chromosomes in dividing cells in order to understand the relatio...The stability and evolution of human genetics depend on chromosomes and chromosome-chromosome interactions.We wish to understand the spatial location of chromosomes in dividing cells in order to understand the relationship between chromosome-chromosome interactions and to further investigate the role of chromosomes and their impact on cell biological behavior.In this study,we explored the relative spatial positional relationships of chromosomes[t(9;22)and t(15;17)]in B-ALL cells by using the three-dimensional DNA fluorescent in situ hybridization(3D-FISH)method.The results showed that chromosomes[t(9;22)and t(15;17)]showed relatively stable spatial relationships.The relative stability of the spatial location of chromosomes in dividing cells may be relevant to disease.展开更多
Aim: To study the integration of hepatitis B virus (HBV) DNA into sperm chromosomes in hepatitis B patients and the features of its integration. Methods: Sperm chromosomes of 14 subjects (5 healthy controls and 9 HB p...Aim: To study the integration of hepatitis B virus (HBV) DNA into sperm chromosomes in hepatitis B patients and the features of its integration. Methods: Sperm chromosomes of 14 subjects (5 healthy controls and 9 HB patients, including 1 acute hepatitis B, 2 chronic active hepatitis B, 4 chronic persistent hepatitis B, 2 HBsAg chronic carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free hamster oocytes and human spermatozoa. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes. Results: Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis B. In 9(9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots and the others 2 to 4 signals. The fluorescence intensity showed significant difference among the signal spots. The distribution of signal sites among chromosomes seems to be random. Conclusion: HBV could integrate into human sperm chromosomes. Results suggest that the possibility of vertical transmission of HBV via the germ line to the next generation is present.展开更多
AIM: To evaluate the level of sperm chromosome aberrations in male patients with hepatitis B, and to directly detect whether there are HBV DNA integrations in sperm chromosomes of hepatitis B patients.METHODS: Sperm c...AIM: To evaluate the level of sperm chromosome aberrations in male patients with hepatitis B, and to directly detect whether there are HBV DNA integrations in sperm chromosomes of hepatitis B patients.METHODS: Sperm chromosomes of 14 tested subjects (5healthy controls, 9 patients with HBV infection, including 1with acute hepatitis B, 2 with chronic active hepatitis B, 4with chronic persistent hepatitis B, 2 chronic HBsAg carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free golden hamster ova and human spermatozoa, and the frequencies of aberration spermatozoa were compared between subjects of HBV infection and controls. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes.RESULTS: The total frequency of sperm chromosome aberrations in HBV infection group (14.8%, 33/223) was significantly higher than that in the control group (4.3%,5/116). Moreover, the sperm chromosomes in HBV infection patients commonly presented stickiness, clumping, failure to staining, etc, which would affect the analysis of sperm chromosomes. Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis. In 9 (9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots, others presented 2 to 4signals. There was significant difference of fluorescence intensity among the signal spots. The distribution of signal sites among chromosomes was random.CONCLUSION: HBV infection can bring about mutagenic effects on sperm chromosomes. Integrations of viral DNA into sperm chromosomes which are multisites and nonspecific, can further increase the instability of sperm chromosomes. This study suggested that HBV infection can create extensively hereditary effects by alteration genetic constituent and/or induction chromosome aberrations, as well as the possibility of vertical transmission of HBV via the germ line to the next generation.展开更多
The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectivel...The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions.展开更多
Psathyrostachys huashanica Keng(2n=2x=14,NsNs)is regarded as a valuable wild relative species for common wheat cultivar improvement because of its abundant beneficial agronomic traits.However,although the development ...Psathyrostachys huashanica Keng(2n=2x=14,NsNs)is regarded as a valuable wild relative species for common wheat cultivar improvement because of its abundant beneficial agronomic traits.However,although the development of many wheat–P.huashanica-derived lines provides a germplasm base for the transfer of excellent traits,the lag in the identification of P.huashanica chromosomes in the wheat background has limited the study of these lines.In this study,three novel nondenaturing fluorescence in situ hybridization(ND-FISH)-positive oligo probes were developed.Among them,HS-TZ3 and HS-TZ4 could specifically hybridize with P.huashanica chromosomes,mainly in the telomere area,and HS-CHTZ5 could hybridize with the chromosomal centromere area.We sequentially constructed a P.huashanica FISH karyotype and idiogram that helped identify the homologous groups of introduced P.huashanica chromosomes.In detail,1Ns and 2Ns had opposite signals on the short and long arms,3Ns,4Ns,and 7Ns had superposed two-color signals,5Ns and 6Ns had fluorescent signals only on their short arms,and 7Ns had signals on the intercalary of the long arm.In addition,we evaluated different ways to identify alien introgression lines by using low-density single nucleotide polymorphism(SNP)arrays and recommended the SNP homozygosity rate in each chromosome as a statistical pattern.The 15K SNP array is widely applicable for addition,substitution,and translocation lines,and the 40K SNP array is the most accurate for recognizing transposed intervals between wheat and alien chromosomes.Our research provided convenient methods to distinguish the homologous group of P.huashanica chromosomes in a common wheat background based on ND-FISH and SNP arrays,which is of great significance for efficiently identifying wheat–P.huashanica-derived lines and the further application of Ns chromosomes.展开更多
Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lin...Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.展开更多
The presence of actin in eukaryotic nuclei and chromosomes, and especially in higher plant nuclei and chromosomes, has not been well established. We detected actin in meristematic cells of Allium cepa with indirect im...The presence of actin in eukaryotic nuclei and chromosomes, and especially in higher plant nuclei and chromosomes, has not been well established. We detected actin in meristematic cells of Allium cepa with indirect immunofluorescence technique and observed bright fluorescence in the intact nuclei and chromosomes, indicating that actin is present in the nuclei and chromosomes of the higher plant. We labeled sections of the meristematic cells of A. cepa with immunogold technique, gold particles were found over the whole nuclei and a number of gold particles were concentrated in condensed chromatin and nucleoli, confirming the results of the immunofluoresence observations. We treated the nuclei and chromosomes of A.cepa with DNase I and 2M NaCl and obtained DNA- and histone-depleted nuclei and chromosomes. Indirect immunofluorescence tests showed that the DNA- and histonedepleted nuclei and chromosomes reacted positively with the anti-actin antibodies. These results demonstrate that actin exists not only in intact nuclei and chromosomes,but also in DNA- and histone-depleted nuclei and chrmosomes of the plant. In addition, our immuno-fluorescence tests indicate that tropomyosin is present in the nuclei and chromosomes of A. cepa.展开更多
While Upland cotton(Gossypium hirsutum L.) represents 95% of the world production,its genetic improvement is hindered by the shortage of effective genomic tools and resources.The
In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between ma...In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between males and females, with additional advantages of small effective population size, suf- ficient markers, and population-specific haplotype distribution （Jobling and Tyler-Smith, 1995; Jin and Su, 2000; Underhill et al., 2000）. Many such population studies have rested on the assumption that all the Y chromosome markers in the non- recombination regions are selectively neutral （Jobling and Tyler-Smith, 2003）.展开更多
Cytogenetic analysis requires cytological preparations that unequivocally reveal the chromosome number and permit optimal visualizations of chromosome morphology for the construction of karyotypes and ideograms. Chrom...Cytogenetic analysis requires cytological preparations that unequivocally reveal the chromosome number and permit optimal visualizations of chromosome morphology for the construction of karyotypes and ideograms. Chromosomal characterization is possible only by establishing these two parameters. To cytogenetically characterize the weed Conyza bonariensis (L.) Cronquist (Asteraceae), it was necessary to improve cytological analysis techniques to obtain optimal results. This species belongs to a genus whose plants have wide phenotypic plasticity. These plants can be morphologically differentiated by other types of analysis, and thus the application of this technique will serve as a reference for cytogenetical analysis of other groups of plants that have cytogenetic characteristics similar to those of C. bonariensis. The methodology described here highlights three main protocol steps: 1) root tip collection from newly germinated seed radicles and from young root tips of mature plants, 2) pretreatment of meristems with antimitotic agents, both isolated and combined, and 3) acid and enzymatic hydrolytic processes.展开更多
[Objective] This study aimed to investigate the chromosomes and karyotypes of three seagrass species of hydrocharitaceae-Enhalus acoroides, Thalassia hemprichii and Halophila minor collected from Li’an Lagoon, Hainan...[Objective] This study aimed to investigate the chromosomes and karyotypes of three seagrass species of hydrocharitaceae-Enhalus acoroides, Thalassia hemprichii and Halophila minor collected from Li’an Lagoon, Hainan Province, China. [Method] The root-tips of E. acoroides, T. hemprichii and the axillary buds of H. minor were selected as the materials in this study. The conventional crushing method was used to prepare the slice specimens of chromosomes, and the karyotypes of the three species were analyzed. [Result] The chromosome numbers of E. acoroides, T. hemprichii and H. minor were 2n=18, 18, 28, respectively. The karyotype formulas were K （2n）=18= 12m＋6sm, K（2n）=18=12m＋6sm and K（2n）=28=16m＋8sm＋4st, respectively. According to the standard of Stebbins, the karyotypes of E. acoroides and T. hemprichii were 2A, and that of H. minor was 2B. There was no B chromosome and satellite in these three species. [Conclusion] According to the comparison on the karyotypes of this three species, E. acoroides and T. hemprichii are similar in karyotypes to each other, indicating that there is close, inter-relationship between E. acoroides and T. hemprichii.展开更多
In studying the XCAP-C-like protein in the root meristematic cells of Allium sativa L., the nuclei were isolated from the cells and the nuclear matrices prepared. A 165 kD polypeptide, which is equivalent to XCAP-C in...In studying the XCAP-C-like protein in the root meristematic cells of Allium sativa L., the nuclei were isolated from the cells and the nuclear matrices prepared. A 165 kD polypeptide, which is equivalent to XCAP-C in molecular weight, was demonstrated in the nuclei by SDS-PAGE, and was then proved to be an XCAP-C-like protein by Western blot using an anti-XCAP-C antiserum, but neither the polypeptide nor the XCAP-C-like protein was detected in die nuclear matrix. The nuclei, Chromosomes and chromosome scaffolds were observed to emanate strong, specific fluorescence after labeled with the anti-XCAP-C antiserum and an FITC-conjugated secondary antibody, indicating their containment of the XCAP-C-like protein. It was confirmed by viewing with immunoelectron microscopy that the gold particles representing the localization of the XCAP-C-like protein were found to be mainly distributed in the condensed chromatin regions of the nuclei and chromosomes.展开更多
In order to avoid any possible effect of separating procedures from intact cell on morphologic structure of the chromosomes, cultivated Hep-2 tumor cells were treated with colchicine and observed by soft X-ray contact...In order to avoid any possible effect of separating procedures from intact cell on morphologic structure of the chromosomes, cultivated Hep-2 tumor cells were treated with colchicine and observed by soft X-ray contact microscopy for the first time. The fine structures of chromosomes are more clear with stereo features. The thread-like and coarse granular structures twine and tangle up together within chromosome masses which can not easily be revealed in Wright’s stained sample by light microscope or osmium stained sample by transmission electron展开更多
Dear Editor, Translocations of the same chromosomal fragments to two or more different chromosomes in different somatic cell lineages are referred to as jumping translocations (JTs).JTs have been mainly reported in he...Dear Editor, Translocations of the same chromosomal fragments to two or more different chromosomes in different somatic cell lineages are referred to as jumping translocations (JTs).JTs have been mainly reported in hematological malignancies but have been observed in rare instances also as constitutional chromosomal aberrations.2 The underlying JT mechanism remains unclear,however.展开更多
BACKGROUND The research findings suggest that the prognosis of children with Wilms tumor(WT)is affected by various factors.Some scholars have indicated that loss of heterozygosity(LOH)on chromosome 16q is associated w...BACKGROUND The research findings suggest that the prognosis of children with Wilms tumor(WT)is affected by various factors.Some scholars have indicated that loss of heterozygosity(LOH)on chromosome 16q is associated with a poor prognosis in patients with WT.AIM To further elucidate this relationship,we conducted a meta-analysis.METHODS This meta-analysis was registered in INPLASY(INPLASY2023100060).We systematically searched databases including Embase,PubMed,Web of Science,Cochrane,and Google Scholar up to May 31,2020,for randomized trials reporting any intrapartum fetal surveillance approach.The meta-analysis was performed within a frequentist framework,and the quality and network inconsistency of trials were assessed.Odds ratios and 95%CIs were calculated to report the relationship between event-free survival and 16q LOH in patients with WT.RESULTS Eleven cohort studies were included in this meta-analysis to estimate the relationship between event-free survival and 16q LOH in patients with WT(I^(2)=25%,P<0.001).As expected,16q LOH can serve as an effective predictor of eventfree survival in patients with WT(risk ratio=1.95,95%CI:1.52–2.49,P<0.001).CONCLUSION In pediatric patients with WT,there exists a partial correlation between 16q LOH and an unfavorable treatment prognosis.Clinical detection of 16q chromosome LOH warrants increased attention to the patient’s prognosis.展开更多
In eukaryotes, a cascade of events named DNA damage response (DDR) has evolved to handle DNA lesions. DDR engages the recruitment of signaling, checkpoint control, repair and chromatin remodeling protein complexes, al...In eukaryotes, a cascade of events named DNA damage response (DDR) has evolved to handle DNA lesions. DDR engages the recruitment of signaling, checkpoint control, repair and chromatin remodeling protein complexes, allowing cell cycle delay, DNA repair or induction of apoptosis. An early DDR event involves the phosphorylation of the histone variant γH2AX on serine 139 (H2AX139 phosphorylation) originating the so-called γH2AX. DDR-related H2AX139 phosphorylation have been extensively studied in interphase nuclei. More recently, γH2AX signals on mitotic chromosomes of asynchronously growing cell cultures were observed. We performed a quantitative analysis of γH2AX signals on γH2AX immunolabeled cytocentrifuged metaphase spreads, analyzing the γH2AX signal distributions of CHO9 chromosomes harboring homologous regions both in control and bleomycin (BLM)-treated cultures. We detected γH2AX signals in CHO9 chromosomes of controls which significantly increase after BLM-exposure. γH2AX signals were uniformly distributed in chromosomes of controls. However, the γH2AX signal distribution in BLM exposed cells was significantly different between chromosomes and among chromosome regions, with few signals near the centromeres and a tendency to increase towards the telomeres. Interestingly, both basal and BLM-induced γH2AX signal distribution were statistically equal between CHO9 homologous chromosome regions. Our results suggest that BLM exerts an effect on H2AX139 phosphorylation, prevailing towards acetylated and gene-rich distal chromosome segments. The comparable H2AX139 phosphorylation of homologous regions puts forward its dependence on chromatin structure or function and its independence of the position in the karyotype.展开更多
文摘Purpose:Derivative chromosomes,resulting from complex structural rearrangements,pose significant challenges in prenatal diagnosis due to their unpredictable inheritance patterns and potential phenotypic consequences.This study evaluates the efficacy of multiple genetic technologies-including karyotyping,fluorescence in situ hybridization(FISH),chromosomal microarray analysis(CMA),and next-generation sequencing(NGS)-in detecting and characterizing derivative chromosomes in prenatal samples.methodology:We analyzed 150 cases of suspected chromosomal abnormalities,comparing detection rates,resolution,and clinical utility across these methods.Results:Our findings demonstrate that integrated multi-technology approaches significantly improve diagnostic accuracy,with NGS-based structural variation analysis achieving the highest detection sensitivity(99.2%)for cryptic rearrangements.Conclusions:Additionally,long-read sequencing(PacBio/Oxford Nanopore)enabled precise breakpoint mapping in 92%of cases,facilitating more accurate genetic counseling.Clinically,this approach enhances risk assessment for fetal anomalies,guides pregnancy management,and improves parental counseling for recurrence risks.
基金supported by the National Natural Science Foundation of China(Nos.52091545 and 51978645).
文摘The objective of this study is to quantitatively reveal the main genetic carrier of antibiotic resistance genes(ARGs)for blocking their environmental dissemination.The distribution of ARGs in chromosomes,plasmids,and phages for understanding their respective contributions to the development of antimicrobial resistance in aerobic biofilm consortium under increasing stresses of oxytetracycline,streptomycin,and tigecyclinewere revealed based on metagenomics analysis.Results showed that the plasmids harbored 49.2%-83.9%of resistomes,which was higher(p<0.001)than chromosomes(2.0%-35.6%),and no ARGs were detected in phage contigs under the strict alignment standard of over 80%identity used in this study.Plasmids and chromosomes tended to encode different types of ARGs,whose abundances all increased with the hike of antibiotic concentrations,and the variety of ARGs encoded by plasmids(14 types and 64 subtypes)was higher than that(11 types and 27 subtypes)of chromosomes.The dosing of the three antibiotics facilitated the transposition and recombination of ARGs on plasmids,mediated by transposable and integrable transfer elements,which increased the co-occurrence of associated and unassociated ARGs.The results quantitatively proved that plasmids dominate the proliferation of ARGs in aerobic biofilm driven by antibiotic selection,which should be a key target for blocking ARG dissemination.
文摘The stability and evolution of human genetics depend on chromosomes and chromosome-chromosome interactions.We wish to understand the spatial location of chromosomes in dividing cells in order to understand the relationship between chromosome-chromosome interactions and to further investigate the role of chromosomes and their impact on cell biological behavior.In this study,we explored the relative spatial positional relationships of chromosomes[t(9;22)and t(15;17)]in B-ALL cells by using the three-dimensional DNA fluorescent in situ hybridization(3D-FISH)method.The results showed that chromosomes[t(9;22)and t(15;17)]showed relatively stable spatial relationships.The relative stability of the spatial location of chromosomes in dividing cells may be relevant to disease.
文摘Aim: To study the integration of hepatitis B virus (HBV) DNA into sperm chromosomes in hepatitis B patients and the features of its integration. Methods: Sperm chromosomes of 14 subjects (5 healthy controls and 9 HB patients, including 1 acute hepatitis B, 2 chronic active hepatitis B, 4 chronic persistent hepatitis B, 2 HBsAg chronic carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free hamster oocytes and human spermatozoa. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes. Results: Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis B. In 9(9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots and the others 2 to 4 signals. The fluorescence intensity showed significant difference among the signal spots. The distribution of signal sites among chromosomes seems to be random. Conclusion: HBV could integrate into human sperm chromosomes. Results suggest that the possibility of vertical transmission of HBV via the germ line to the next generation is present.
基金the Natural Science Foundation of Guangdong Province,No.940567the National Natural Science Foundation of China,No.39970374
文摘AIM: To evaluate the level of sperm chromosome aberrations in male patients with hepatitis B, and to directly detect whether there are HBV DNA integrations in sperm chromosomes of hepatitis B patients.METHODS: Sperm chromosomes of 14 tested subjects (5healthy controls, 9 patients with HBV infection, including 1with acute hepatitis B, 2 with chronic active hepatitis B, 4with chronic persistent hepatitis B, 2 chronic HBsAg carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free golden hamster ova and human spermatozoa, and the frequencies of aberration spermatozoa were compared between subjects of HBV infection and controls. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes.RESULTS: The total frequency of sperm chromosome aberrations in HBV infection group (14.8%, 33/223) was significantly higher than that in the control group (4.3%,5/116). Moreover, the sperm chromosomes in HBV infection patients commonly presented stickiness, clumping, failure to staining, etc, which would affect the analysis of sperm chromosomes. Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis. In 9 (9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots, others presented 2 to 4signals. There was significant difference of fluorescence intensity among the signal spots. The distribution of signal sites among chromosomes was random.CONCLUSION: HBV infection can bring about mutagenic effects on sperm chromosomes. Integrations of viral DNA into sperm chromosomes which are multisites and nonspecific, can further increase the instability of sperm chromosomes. This study suggested that HBV infection can create extensively hereditary effects by alteration genetic constituent and/or induction chromosome aberrations, as well as the possibility of vertical transmission of HBV via the germ line to the next generation.
文摘The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions.
基金the National Natural Science Foundation of China(31501301)the National Key Research and Development Program of China(2018YFD0100904)+1 种基金the Natural Science Foundation of Henan Province,China(162300410077)the International Cooperation Project of Henan Province,China(172102410052)。
文摘Psathyrostachys huashanica Keng(2n=2x=14,NsNs)is regarded as a valuable wild relative species for common wheat cultivar improvement because of its abundant beneficial agronomic traits.However,although the development of many wheat–P.huashanica-derived lines provides a germplasm base for the transfer of excellent traits,the lag in the identification of P.huashanica chromosomes in the wheat background has limited the study of these lines.In this study,three novel nondenaturing fluorescence in situ hybridization(ND-FISH)-positive oligo probes were developed.Among them,HS-TZ3 and HS-TZ4 could specifically hybridize with P.huashanica chromosomes,mainly in the telomere area,and HS-CHTZ5 could hybridize with the chromosomal centromere area.We sequentially constructed a P.huashanica FISH karyotype and idiogram that helped identify the homologous groups of introduced P.huashanica chromosomes.In detail,1Ns and 2Ns had opposite signals on the short and long arms,3Ns,4Ns,and 7Ns had superposed two-color signals,5Ns and 6Ns had fluorescent signals only on their short arms,and 7Ns had signals on the intercalary of the long arm.In addition,we evaluated different ways to identify alien introgression lines by using low-density single nucleotide polymorphism(SNP)arrays and recommended the SNP homozygosity rate in each chromosome as a statistical pattern.The 15K SNP array is widely applicable for addition,substitution,and translocation lines,and the 40K SNP array is the most accurate for recognizing transposed intervals between wheat and alien chromosomes.Our research provided convenient methods to distinguish the homologous group of P.huashanica chromosomes in a common wheat background based on ND-FISH and SNP arrays,which is of great significance for efficiently identifying wheat–P.huashanica-derived lines and the further application of Ns chromosomes.
基金financially supported by the National Key Research and Development Program of China(2016YFD0102001 and 2016YFD0102002)the National Natural Science Foundation of China(31771788)the Agricultural Science and Technology Innovation Program(ASTIP)of the Chinese Academy of Agricultural Sciences
文摘Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.
文摘The presence of actin in eukaryotic nuclei and chromosomes, and especially in higher plant nuclei and chromosomes, has not been well established. We detected actin in meristematic cells of Allium cepa with indirect immunofluorescence technique and observed bright fluorescence in the intact nuclei and chromosomes, indicating that actin is present in the nuclei and chromosomes of the higher plant. We labeled sections of the meristematic cells of A. cepa with immunogold technique, gold particles were found over the whole nuclei and a number of gold particles were concentrated in condensed chromatin and nucleoli, confirming the results of the immunofluoresence observations. We treated the nuclei and chromosomes of A.cepa with DNase I and 2M NaCl and obtained DNA- and histone-depleted nuclei and chromosomes. Indirect immunofluorescence tests showed that the DNA- and histonedepleted nuclei and chromosomes reacted positively with the anti-actin antibodies. These results demonstrate that actin exists not only in intact nuclei and chromosomes,but also in DNA- and histone-depleted nuclei and chrmosomes of the plant. In addition, our immuno-fluorescence tests indicate that tropomyosin is present in the nuclei and chromosomes of A. cepa.
文摘While Upland cotton(Gossypium hirsutum L.) represents 95% of the world production,its genetic improvement is hindered by the shortage of effective genomic tools and resources.The
基金supported by the National Excellent Youth Science Foundation of China (No. 31222030)the National Natural Science Foundation of China (Nos. 31071098 and 91131002)+2 种基金the Shanghai Rising-Star Program (No. 12QA1400300)the Shanghai Commission of Education Research Innovation Key Project (No. 11zz04)the Shanghai Professional Development Funding (No. 2010001)
文摘In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between males and females, with additional advantages of small effective population size, suf- ficient markers, and population-specific haplotype distribution （Jobling and Tyler-Smith, 1995; Jin and Su, 2000; Underhill et al., 2000）. Many such population studies have rested on the assumption that all the Y chromosome markers in the non- recombination regions are selectively neutral （Jobling and Tyler-Smith, 2003）.
文摘Cytogenetic analysis requires cytological preparations that unequivocally reveal the chromosome number and permit optimal visualizations of chromosome morphology for the construction of karyotypes and ideograms. Chromosomal characterization is possible only by establishing these two parameters. To cytogenetically characterize the weed Conyza bonariensis (L.) Cronquist (Asteraceae), it was necessary to improve cytological analysis techniques to obtain optimal results. This species belongs to a genus whose plants have wide phenotypic plasticity. These plants can be morphologically differentiated by other types of analysis, and thus the application of this technique will serve as a reference for cytogenetical analysis of other groups of plants that have cytogenetic characteristics similar to those of C. bonariensis. The methodology described here highlights three main protocol steps: 1) root tip collection from newly germinated seed radicles and from young root tips of mature plants, 2) pretreatment of meristems with antimitotic agents, both isolated and combined, and 3) acid and enzymatic hydrolytic processes.
基金Supported by the State key Subjecet of Botany at Hainan University (071001)the Malor Scientific Research Protect of Hainan Province, China(20080137)~~
文摘[Objective] This study aimed to investigate the chromosomes and karyotypes of three seagrass species of hydrocharitaceae-Enhalus acoroides, Thalassia hemprichii and Halophila minor collected from Li’an Lagoon, Hainan Province, China. [Method] The root-tips of E. acoroides, T. hemprichii and the axillary buds of H. minor were selected as the materials in this study. The conventional crushing method was used to prepare the slice specimens of chromosomes, and the karyotypes of the three species were analyzed. [Result] The chromosome numbers of E. acoroides, T. hemprichii and H. minor were 2n=18, 18, 28, respectively. The karyotype formulas were K （2n）=18= 12m＋6sm, K（2n）=18=12m＋6sm and K（2n）=28=16m＋8sm＋4st, respectively. According to the standard of Stebbins, the karyotypes of E. acoroides and T. hemprichii were 2A, and that of H. minor was 2B. There was no B chromosome and satellite in these three species. [Conclusion] According to the comparison on the karyotypes of this three species, E. acoroides and T. hemprichii are similar in karyotypes to each other, indicating that there is close, inter-relationship between E. acoroides and T. hemprichii.
文摘In studying the XCAP-C-like protein in the root meristematic cells of Allium sativa L., the nuclei were isolated from the cells and the nuclear matrices prepared. A 165 kD polypeptide, which is equivalent to XCAP-C in molecular weight, was demonstrated in the nuclei by SDS-PAGE, and was then proved to be an XCAP-C-like protein by Western blot using an anti-XCAP-C antiserum, but neither the polypeptide nor the XCAP-C-like protein was detected in die nuclear matrix. The nuclei, Chromosomes and chromosome scaffolds were observed to emanate strong, specific fluorescence after labeled with the anti-XCAP-C antiserum and an FITC-conjugated secondary antibody, indicating their containment of the XCAP-C-like protein. It was confirmed by viewing with immunoelectron microscopy that the gold particles representing the localization of the XCAP-C-like protein were found to be mainly distributed in the condensed chromatin regions of the nuclei and chromosomes.
基金The Project Supported by National Natural Science Foundation of China
文摘In order to avoid any possible effect of separating procedures from intact cell on morphologic structure of the chromosomes, cultivated Hep-2 tumor cells were treated with colchicine and observed by soft X-ray contact microscopy for the first time. The fine structures of chromosomes are more clear with stereo features. The thread-like and coarse granular structures twine and tangle up together within chromosome masses which can not easily be revealed in Wright’s stained sample by light microscope or osmium stained sample by transmission electron
文摘Dear Editor, Translocations of the same chromosomal fragments to two or more different chromosomes in different somatic cell lineages are referred to as jumping translocations (JTs).JTs have been mainly reported in hematological malignancies but have been observed in rare instances also as constitutional chromosomal aberrations.2 The underlying JT mechanism remains unclear,however.
基金Supported by Yunnan Provincial Department of Science and Technology Provincial Basic Research Program(Kunming Medical Joint Special Project,No.2019FE001(-276)Kunming Health Science and Technology Talents Training Project and"Ten Hundred Thousands"Project Training Plan,No.2020-SW(Backup)-121.
文摘BACKGROUND The research findings suggest that the prognosis of children with Wilms tumor(WT)is affected by various factors.Some scholars have indicated that loss of heterozygosity(LOH)on chromosome 16q is associated with a poor prognosis in patients with WT.AIM To further elucidate this relationship,we conducted a meta-analysis.METHODS This meta-analysis was registered in INPLASY(INPLASY2023100060).We systematically searched databases including Embase,PubMed,Web of Science,Cochrane,and Google Scholar up to May 31,2020,for randomized trials reporting any intrapartum fetal surveillance approach.The meta-analysis was performed within a frequentist framework,and the quality and network inconsistency of trials were assessed.Odds ratios and 95%CIs were calculated to report the relationship between event-free survival and 16q LOH in patients with WT.RESULTS Eleven cohort studies were included in this meta-analysis to estimate the relationship between event-free survival and 16q LOH in patients with WT(I^(2)=25%,P<0.001).As expected,16q LOH can serve as an effective predictor of eventfree survival in patients with WT(risk ratio=1.95,95%CI:1.52–2.49,P<0.001).CONCLUSION In pediatric patients with WT,there exists a partial correlation between 16q LOH and an unfavorable treatment prognosis.Clinical detection of 16q chromosome LOH warrants increased attention to the patient’s prognosis.
文摘In eukaryotes, a cascade of events named DNA damage response (DDR) has evolved to handle DNA lesions. DDR engages the recruitment of signaling, checkpoint control, repair and chromatin remodeling protein complexes, allowing cell cycle delay, DNA repair or induction of apoptosis. An early DDR event involves the phosphorylation of the histone variant γH2AX on serine 139 (H2AX139 phosphorylation) originating the so-called γH2AX. DDR-related H2AX139 phosphorylation have been extensively studied in interphase nuclei. More recently, γH2AX signals on mitotic chromosomes of asynchronously growing cell cultures were observed. We performed a quantitative analysis of γH2AX signals on γH2AX immunolabeled cytocentrifuged metaphase spreads, analyzing the γH2AX signal distributions of CHO9 chromosomes harboring homologous regions both in control and bleomycin (BLM)-treated cultures. We detected γH2AX signals in CHO9 chromosomes of controls which significantly increase after BLM-exposure. γH2AX signals were uniformly distributed in chromosomes of controls. However, the γH2AX signal distribution in BLM exposed cells was significantly different between chromosomes and among chromosome regions, with few signals near the centromeres and a tendency to increase towards the telomeres. Interestingly, both basal and BLM-induced γH2AX signal distribution were statistically equal between CHO9 homologous chromosome regions. Our results suggest that BLM exerts an effect on H2AX139 phosphorylation, prevailing towards acetylated and gene-rich distal chromosome segments. The comparable H2AX139 phosphorylation of homologous regions puts forward its dependence on chromatin structure or function and its independence of the position in the karyotype.
