Hollow Lindqvist-like-Shaped {V6} Cluster-Based Metal-Organic Framework for the Highly Efficient Detoxification of Mustard Gas Simulant.

A polyoxovanadate-based nickel-organic framework, [Ni(bib)2]{V2O6}({V6}-MOF, bib = 1,4-bis(1H-imidazoly-1-yl)benzene), was facilely prepared under gentle hydrothermal conditions and structurally characterized. Single-crystal X-ray diffraction analysis indicates that the {V6} cluster in the {V6}-MOF is constructed of two VO5 tetragonal pyramids and four VO4 tetrahedrons via the apex sharing of O atoms, presenting a hollow Linqvist-like structure, which is different from these reported hexanuclear vanadium clusters. The {V6}-MOF not only expands the structure of polyoxovanadates (POVs) but also catalyzes the rapid detoxification of mustard gas simulant (2-chloroethyl ethyl sulfide, CEES) at 25 °C. The catalytic results were determined by means of GC, GC-MS, and 1H NMR. Using {V6}-MOF as a heterogeneous catalyst, CEES underwent catalyzed oxidation to only nontoxic product 2-chloroethyl ethyl sulfoxide (CEESO) within 40 min, and the conversion and selectivity were almost 100%. In addition, {V6}-MOF exhibits high sustainability, and no obvious reductions in conversion and selectivity are observed after five runs.

Identification of quality gaps in healthcare services using the SERVQUAL instrument and importance-performance analysis in medical intensive care: a prospective study at a medical center in Taiwan.

BACKGROUND: Assessing patients' expectations and perceptions of health service delivery is challenging. To understand the service quality in intensive care units (ICUs), we investigated the expected and perceived service quality of ICU care. METHODS: We conducted this study at an ICU of a university-affiliated medical center in Taiwan from April to September 2019. Admitted patients or their family members responded to a questionnaire survey adopted from the SERVQUAL instrument consisting of 22 items in five dimensions. The questionnaire was provided on ICU admission for expectation and before ICU discharge for perception. We analyzed the quality gaps between the surveys and applied important-performance analysis (IPA). RESULTS: A total of 117 patients were included (62.4% males, average age: 65.9 years, average length of stay: 10.1 days, and 76.9% survival to ICU discharge). The overall weighted mean scores for the surveys were similar (4.57 ± 0.81 and 4.58 ± 0.52, respectively). The 'tangibles' dimension had a higher perception than expectation (3.99 ± 0.55 and 4.31 ± 0.63 for expectation and perception, respectively, p < 0.001). IPA showed that most of the items in 'reliability,' 'responsiveness' and 'assurance' were located in the quadrant of high expectation and high perception, whereas most of the items in 'tangibles' and 'empathy' were located in the quadrant of low expectation and low perception. One item (item 1 for 'tangibles') was found in the quadrant of high expectation and low perception. CONCLUSIONS: The SERVQUAL approach and IPA might provide useful information regarding the feedback by patients and their families for ICU service quality. In most aspects, the performance of the ICU satisfactorily matched the needs perceived by the patients and their families.

Extreme diversity and multiple SCCmec elements in coagulase-negative Staphylococcus found in the Clinic and Community in Beijing, China.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are recognized as a large reservoir of staphylococcal cassette chromosome mec (SCCmec) harboured by Staphylococcus aureus. However, data of SCCmec in CoNS are relatively absent particularly in China. METHODS: Seventy-eight CoNS clinical and 47 community isolates were collected in Beijing. PCR was performed to classify SCCmec types. Under oxacillin treatment, quantitative real-time reverse transcription PCR (qRT-PCR) was performed to compare mecA mRNA levels and mRNA half-life between isolates with single SCCmec element and those with multiple one. Their growth curves were analysed. Their bacterial cell wall integrity was also compared by performing a Gram stain. All ccr complex segments were sequenced and obtained ccr segments were analysed by phylogenetic analyses. RESULTS: All 78 clinical isolates had mecA segments compared with 38% in community isolates (total 47). Only 29% clinical isolates and 33% community isolates (among mecA positive isolates) harboured a single previously identified SCCmec type; notably, 17% clinical isolates and 28% community isolates had multiple SCCmec types. Further studies indicated that isolates with multiple SCCmec elements had more stable mecA mRNA expression compared with isolates with single SCCmec elements. CoNS with multiple SCCmec elements demonstrated superior cell wall integrity. Interestingly, phylogenetic analyses of obtained 70 ccr segments indicated that horizontal gene transfer of the ccr complex might exist among various species of clinical CoNS, community CoNS and S. aureus. CONCLUSIONS: CoNS recovered from patients carried extremely diverse but distinctive SCCmec elements compared with isolates from the community. More attention should be given to CoNS with multiple SCCmec not only because they had superior cell wall integrity, but also because CoNS and S. aureus might acquire multiple SCCmec through the ccr complex.

[Effect of atopy on serum glucocorticoid receptor levels in children with bronchiolitis].

OBJECTIVE: To investigate the effect of atopy on the expression of glucocorticoid receptors in children with bronchiolitis. METHODS: ELISA was used to measure the changes in the serum levels of glucocorticoid receptor α (GRα) and glucocorticoid receptor ß (GRß) in the bronchiolitis group (77 children, including 34 children with atopy) and pneumonia group (68 children). Thirty-eight children who were prepared to undergo surgeries for non-infectious diseases and had no atopy or family history of allergic diseases were enrolled as the control group. RESULTS: The bronchiolitis group and the pneumonia group had significant increases in the serum levels of GRα and GRß compared with the control group (P<0.01), and the bronchiolitis group had significant increases in these levels compared with the pneumonia group (P<0.01). Compared with the control group and the pneumonia group, the bronchiolitis group had a significant increase in the GRα/GRß ratio (P<0.01). Compared with the control group, the children with or without atopy in the bronchiolitis group had significant increases in the serum levels of GRα and GRß (P<0.01). The non-atopic children in the bronchiolitis group had a significant increase in the serum level of GRß compared with the atopic children (P<0.01). The atopic children in the bronchiolitis group had a significant increase in the GRα/GRß ratio compared with the control group and non-atopic children in the bronchiolitis group (P<0.01). CONCLUSIONS: Children with bronchiolitis have increased serum levels of GRα and GRß. The children with atopy have an increased GRα/GRß ratio, suggesting that the atopic children with bronchiolitis are highly sensitive to glucocorticoids.

Molecular Characteristics and Drug Susceptibility of Mycobacterium tuberculosis Isolates from Patients Co-infected with Human Immunodeficiency Virus in Beijing, China.

70 clinical Mycobacterium tuberculosis strains isolated from AIDS patients in two HIV/AIDS referral hospitals in Beijing were used in this study. M. tuberculosis and non-tuberculosis mycobacterium (NTM) were identified by using multi-locus PCR. M. tuberculosis was genotyped by using 15-locus MIRU-VNTR technique and spoligotyping afterwards. Meanwhile, the drug susceptibilities of the strains to the four first-line anti TB drugs (rifampin, isoniazid, streptomycin, and ethambutol) and the four second-line anti-TB drugs (capreomycin, kanamycin, ofloxacin, and ethionanide) were tested with proportional method. In this study, M. tuberculosis and NTM strains isolated from AIDS patients with TB-like symptoms were identified and genotyping analysis indicated that Beijing genotype was the predominant genotype. In addition, the prevalence of drug-resistant TB, especially the prevalence of XDR-TB, was higher than that in TB patients without HIV infection.

[Determination and clinical significance of serum surfactant proteins A and D in children with bronchiolitis].

OBJECTIVE: To study the variation and clinical significance of serum levels of surfactant proteins A (SP-A) and D (SP-D) among children with different degrees of bronchiolitis. METHODS: Seventy children with bronchiolitis were divided into acute (n=42) and recovery phase groups (n=28). According to the severity of symptoms, the acute phase group was further divided into severe (n=12) and mild subgroups (n=30). Another 26 children who were hospitalized in the same period due to non-infectious diseases and had not undergone surgery were used as the control group. Competitive enzyme-linked immunosorbent assay was performed to measure serum levels of SP-A and SP-D in each group. RESULTS: The acute phase group had significantly higher serum levels of SP-A and SP-D compared with the recovery phase (P<0.01) and control groups (P<0.01). Compared with the control group, the recovery phase group had elevated levels of SP-A and SP-D (P<0.01). Within the acute phase group, serum levels of SP-A and SP-D in the severe subgroup were significantly higher than in the mild subgroup (P<0.01). CONCLUSIONS: Serum levels of SP-A and SP-D are significantly elevated in children with acute bronchiolitis, and severe cases have higher serum levels of SP-A and SP-D than mild cases. Even after the relief of clinical symptoms, serum levels of SP-A and SP-D remain high. These findings suggest that serum levels of SP-A and SP-D might be useful biomarkers for evaluating the severity of bronchiolitis among children.

Determinants of pro-environmental behavior among excessive smartphone usage children and moderate smartphone usage children in Taiwan.

INTRODUCTION: Although there is evidence linking the relationships between smartphone usage with health, stress, and academic performance, there is still inadequate knowledge about the influence on pro-environmental behaviors. This study seeks to bridge this gap by adapting the theory of attribution framework to examine the effects of personal norms, social norms, perceived behavioral control on pro-environmental behavior of smartphone usage in children. METHODS: A total of 225 children aged between 11 to 12 from eight selected public primary schools at the Hsinchu Science and Industrial Park in Taiwan were surveyed. Two distinct groups (excessive versus moderate usage) were purposefully selected for comparison, of which 96 participants were excessive smartphone users while the remaining 129 were moderate smartphone users. RESULTS: Findings revealed significant differences between excessive and moderate smartphone usage children groups in personal norms (p < 0.001), social norms (p = 0.002), perceived behavioral control (p = 0.001), and pro-environmental behavior (p = 0.001). Findings for excessive smartphone usage children showed that social norms (ß = 0.428, t = 4.096***, p < 0.001) had a direct predictive impact on pro-environmental behavior. In contrast, while there was no direct path established between personal norms and pro-environmental behavior (ß = 0.177, t = 1.580, p > 0.05), as well as social norms and pro-environmental behavior for moderate smartphone usage children (ß = 0.181, t = 1.924, p > 0.05), but such a relationship could be developed through the mediating effect of perceived behavioral control (ß = 0.497, t = 4.471***, p < 0.001). DISCUSSION: The results suggested that excessive smartphone usage children lack positive perceived behavioral control, and their pro-environmental behavior could only be predicted through explicit social norms, whereas pro-environmental behavior of moderate smartphone usage children was implicitly influenced by personal norms through perceived behavioral control.

Effects of Parental Involvement in a Preschool-Based Eye Health Intervention Regarding Children's Screen Use in China.

In this digital era, young children spend a considerable amount of time looking at telephone, tablet, computer and television screens. However, preventative eye health behavior education could help avoid and relieve asthenopia. The effects of parental influence on their children's eye health behavior through the preschool eye health education intervention program were examined. The Health Belief Model was used to develop parental involvement strategy and eye health curriculum. The study was conducted in a large public preschool with five branches in Beijing, China. A total of 248 parent-child pairs participated in the baseline and follow-up surveys, of which 129 were in the intervention group and 119 were in the comparison group. The generalized estimating equation analysis results indicated that parental involvement in preschool-based eye health intervention on screen uses had positive influence on parents' eye health knowledge, cues to action, and parenting efficacy. The intervention program also had positive effects on the increasing level of children's eye health knowledge, beliefs, cues to action, self-efficacy, and behaviors. The results supported the implementation of a preschool-based eye health intervention program with parental involvement, which could potentially enhance children's and parents' eye health beliefs and practices.

Synthesis and application in polypropylene of a novel of phosphorus-containing intumescent flame retardant.

A novel phosphorus-containing triazine oligomer poly(2-morpholinyl-4-penta-erythritol phosphate-1,3,5-triazine) (PMPT) was synthesized as a kind of tri-component intumescent flame retardant (IFR). The chemical structure of PMPT was characterized by FTIR, 1H-NMR and 31P-NMR, and the mechanical and flammability properties of FR-PP were measured. The FTIR results showed that the expected chemical reactions had  happened at each step. The 1H-NMR and 31P-NMR spectra also agreed with the chemical structure of PMPT. The slight effect of PMPT on the mechanical properties of FR-PP suggested that PMPT and PP are compatible. The high limited oxygen index (LOI) values of FR-PP revealed that PMPT was an efficient IFR and there was the synergistic effect between PMPT and ammonium polyphosphate/ pentaerythritol (APP/PER).

A universal strategy for fabrication and morphology control of polyoxometalate-based metal-organic frameworks.

A novel method is proposed to fabricate polyoxometalate-based metal-organic frameworks (POM@MOFs) by using the ability of POMs to oxidize metals to cations. The morphology-controlled growth of POM@MOFs (NENU-n) is achieved in the absence of any modulators and an effect of polyoxoanion charge number on morphology is observed.

Identification of activated pathways in lung adenocarcinoma based on network strategy.

BACKGROUND: Lung adenocarcinoma has increased incidence over the past years and is the cause for almost 50% of deaths attributable to lung cancer. The objective of this paper is to identify activated pathways associated with lung adenocarcinoma based on gene co-expression network analysis. MATERIALS AND METHODS: Kyoto Encyclopedia of Genes and Genomes pathway analysis of dysregulated genes was performed based on Expression Analysis Systematic Explorer test to illuminate the biological pathways. Co-expression networks of lung adenocarcinoma in different tumor Stages (IA, IB, IIA, IIB, IIIA, IIIB, and IV) were constructed by Empirical Bayes approach to reweight gene pair scores. Pathway activity analysis was conducted to compute the distribution of pathways in different stages and to identify "activated" pathways in lung adenocarcinoma. RESULTS: We evaluated 211 dysregulated genes between lung adenocarcinoma patients and normal controls. Pathway activity analysis was performed and P values of pathways, which obtained from co-expression networks (Stage IA, IB, IIA, IIB, IIIA, IIIB, and IV), were calculated. Cell cycle, progesterone-mediated oocyte maturation, and oocyte meiosis were activated during all stages in lung adenocarcinoma. CONCLUSIONS: We successfully identified three activated pathways (cell cycle, progesterone-mediated oocyte maturation, and oocyte meiosis) in different Stages (IA, IB, IIA, IIB, IIIA, IIIB, and IV) of lung adenocarcinoma.

The mitochondrial genome of the gymnosperm Cycas taitungensis contains a novel family of short interspersed elements, Bpu sequences, and abundant RNA editing sites.

The mtDNA of Cycas taitungensis is a circular molecule of 414,903 bp, making it 2- to 6-fold larger than the known mtDNAs of charophytes and bryophytes, but similar to the average of 7 elucidated angiosperm mtDNAs. It is characterized by abundant RNA editing sites (1,084), more than twice the number found in the angiosperm mtDNAs. The A + T content of Cycas mtDNA is 53.1%, the lowest among known land plants. About 5% of the Cycas mtDNA is composed of a novel family of mobile elements, which we designated as "Bpu sequences." They share a consensus sequence of 36 bp with 2 terminal direct repeats (AAGG) and a recognition site for the Bpu 10I restriction endonuclease (CCTGAAGC). Comparison of the Cycas mtDNA with other plant mtDNAs revealed many new insights into the biology and evolution of land plant mtDNAs. For example, the noncoding sequences in mtDNAs have drastically expanded as land plants have evolved, with abrupt increases appearing in the bryophytes, and then in the seed plants. As a result, the genomic organizations of seed plant mtDNAs are much less compact than in other plants. Also, the Cycas mtDNA appears to have been exempted from the frequent gene loss observed in angiosperm mtDNAs. Similar to the angiosperms, the 3 Cycas genes nad1, nad2, and nad5 are disrupted by 5 group II intron squences, which have brought the genes into trans-splicing arrangements. The evolutionary origin and invasion/duplication mechanism of the Bpu sequences in Cycas mtDNA are hypothesized and discussed.

[Simulation model for cucumber growth and development in sunlight greenhouse]. / æ—¥å ‰æ¸©å®¤é»„ç“œç”Ÿé•¿å‘è‚²æ¨¡æ‹Ÿæ¨¡åž‹.

The dynamic simulation of cucumber growth and development in sunlight greenhouse can provide technical support for the intelligent management of cucumber production. According to the cucumber response characteristics to light and temperature, the cucumber development module based on the algorithm of clock model was established by using data from four-stage experiment with 'Jinyou 35' as experiment variety in two years. Based on the relationship between the leaf growth and key meteorological factors (temperature and radiation), leaf area index (LAI) module was established with the accumulated product of thermal effectiveness and photosynthetically active radiation (TEP) as independent variables. The simulation module of cucumber dry matter production was established by taking into consideration the double integral of LAI and daily length in photosynthesis per unit leaf area as well as the respiratory expenditure of different organs. Combined with water content of organs, fresh weight simulation module of cucumber organs was constructed. The whole cucumber development and growth simulation model in greenhouse was built based on each sub-module. The model parameters were calibrated and determined. The results showed that root mean square error (RMSE) of simulated values and observed values of four deve-lopment stages (from transplanting date to stretch tendril, to initial flowering, to early harvested and to uprooting), was 3.9-10.5 d. The normalized root mean square error (nRMSE) was 6.5%-28.6%. The coincidence index (D) was 0.79-0.97. The relationship between LAI and TEP was the regression of 'S' type curve. The RMSE of simulated and observed LAI values was 0.19. The nRMSE was 17.2%. The D value was 0.90. The RMSE of dry weight of root, stem, leaf, flower and fruit of the simulated values and observed values were 0.39-8.94 g·m-2. The nRMSE were 10.9%-17.7%. The D values were all above 0.98. The growth and development model of cucumber could accurately simulate the key development period of cucumber, leaf area and the dry and fresh weight of various organs and quantify the growth and development of cucumber in sunlight greenhouse.

Microwave-assisted synthesis of high thermal stability and colourless polyimides containing pyridine.

A novel aromatic diamine containing pyridyl side group, 4-pyridine-4,4-bis(3,5-dimethyl-5-aminophenyl)methane (PyDPM), was successfully synthesized via electrophilic substitution reaction. The polyimides (PIs) containing pyridine were obtained via the microwave-assisted one-step polycondensation of the PyDPM with pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-diphenylether tetracarboxylic dianhydride (ODPA) and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Contrarily to the reported similar PIs, these PIs exhibit much higher thermal stability or heat resistance, i.e. high glass transition temperatures (T gs) in the range of 358-473°C, and the decomposition temperatures at 5% weight loss over 476°C under nitrogen. They can afford flexible and strong films with tensile strength of 82.1-93.3 MPa, elongation at break of 3.7%-15.2%, and Young's modulus of 3.3-3.8 GPa. Furthermore, The PI films exhibit good optical transparency with the cut-off wavelength at 313-366 nm and transmittance higher than 73% at 450 nm. The excellent thermal and optical transmittance can be attributed to synthesis method and the introduction of pyridine rings and ortho-methyl groups. The inherent viscosities of PIs via one-step method were found to be 0.58-1.12 dl g-1 in DMAc, much higher than those via two-step method. These results indicate these PIs could be potential candidates for optical substrates of organic light emitting diodes (OLEDs).

Epidemiology and antifungal susceptibilities of yeast isolates causing invasive infections across urban Beijing, China.

AIM: To investigate the species distribution and antifungal susceptibility profiles of yeast isolates causing invasive infections across Beijing. MATERIALS & METHODS: A total of 1201 yeast isolates recovered from blood and other sterile body fluids were correctly identified by matrix-assisted laser desorption/ionization TOF MS supplemented by DNA sequencing. Antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute broth microdilution method. RESULTS: Candida (95.5%) remained the most common yeast species isolated; Candida albicans (38.8%) and Candida parapsilosis (22.6%) were the leading species of candidemia. Azole resistances were mainly observed in Candida glabrata and Candida tropicalis isolates. CONCLUSION: This study outlined the epidemiologic data of invasive yeast infections and highlighted the need for continuous monitoring of azole resistances among C. glabrata and C. tropicalis isolates in Beijing.

Effect of arsenic trioxide on human hepatocarcinoma in nude mice.

AIM: To study the effect of arsenic trioxide (As(2)0(3)) on human hepatoma cell line BEL-7402 in vivo. METHODS: Human hepatoma cell line BEL-7402 cultured in vitro was inoculated into nude mice and arsenic trioxide, 5-Fu and saline were injected into abdominal cavity of the nude mice respectively. The volumes of tumor and general conditions of the nude mice and structural changes of the liver and kidney were observed. Morphologic changes were studied under electron microscope. Expression of AFP was investigated by immunohistochemical method. RESULTS: As(2)O(3) could inhibit the growth of tumor. The tumor growth inhibitory rate in mice treated with 2.5 mg/kg As(2)O(3) was 53.42% on the tenth day. The tumor growth inhibitory rate in mice treated with 5 mg/kg As(2)O(3) was 79.28% on the fifth day and 96.58% on the tenth day respectively. As(2)O(3) did not damage the liver and kidney of nude mice, or affect the blood system. Typical apoptotic morphological changes were found under electron microscope, and the change of mitochondria was obvious. The expression rate of AFP declined after treatment. CONCLUSION: Arsenic trioxide can induce apoptosis of human hepatoma cells, and inhibit proliferation of tumor with no obvious side effects on liver and kidney.

Taiwanese parents' experience of making a "do not resuscitate" decision for their child in pediatric intensive care unit.

PURPOSE: The purpose of this project was to explore the parental experience of making a "do not resuscitate" (DNR) decision for their child who is or was cared for in a pediatric intensive care unit in Taiwan. METHODS: A descriptive qualitative study was conducted following parental signing of a standard hospital DNR form on behalf of their critically ill child. Sixteen Taiwanese parents of 11 children aged 1 month to 18 years were interviewed. Interviews were recorded, transcribed, analyzed and sorted into themes by the sole interviewer plus other researchers. RESULTS: Three major themes were identified: (a) "convincing points to sign", (b) "feelings immediately after signing", and (c) "post-signing relief or regret". Feelings following signing the DNR form were mixed and included "frustration", "guilt", and "conflicting hope". Parents adjusted their attitudes to thoughts such as "I have done my best," and "the child's life is beyond my control." Some parents whose child had died before the time of the interview expressed among other things "regret not having enough time to be with and talk to my child". CONCLUSION: Open family visiting hours plus staff sensitivity and communication skills training are needed. To help parents with this difficult signing process, nurses and other professionals in the pediatric intensive care unit need education on initiating the conversation, guiding the parents in expressing their fears, and providing continuing support to parents and children throughout the child's end of life process.

Chloroplast genome (cpDNA) of Cycas taitungensis and 56 cp protein-coding genes of Gnetum parvifolium: insights into cpDNA evolution and phylogeny of extant seed plants.

Phylogenetic relationships among the 5 groups of extant seed plants are presently unsettled. To reexamine this long-standing debate, we determine the complete chloroplast genome (cpDNA) of Cycas taitungensis and 56 protein-coding genes encoded in the cpDNA of Gnetum parvifolium. The cpDNA of Cycas is a circular molecule of 163,403 bp with 2 typical large inverted repeats (IRs) of 25,074 bp each. We inferred phylogenetic relationships among major seed plant lineages using concatenated 56 protein-coding genes in 37 land plants. Phylogenies, generated by the use of 3 independent methods, provide concordant and robust support for the monophylies of extant seed plants, gymnosperms, and angiosperms. Within the modern gymnosperms are 2 highly supported sister clades: Cycas-Ginkgo and Gnetum-Pinus. This result agrees with both the "gnetifer" and "gnepines" hypotheses. The sister relationships in Cycas-Ginkgo and Gnetum-Pinus clades are further reinforced by cpDNA structural evidence. Branch lengths of Cycas-Ginkgo and Gnetum were consistently the shortest and the longest, respectively, in all separate analyses. However, the Gnetum relative rate test revealed this tendency only for the 3rd codon positions and the transversional sites of the first 2 codon positions. A PsitufA located between psbE and petL genes is here first detected in Anthoceros (a hornwort), cycads, and Ginkgo. We demonstrate that the PsitufA is a footprint descended from the chloroplast tufA of green algae. The duplication of ycf2 genes and their shift into IRs should have taken place at least in the common ancestor of seed plants more than 300 MYA, and the tRNAPro-GGG gene was lost from the angiosperm lineage at least 150 MYA. Additionally, from cpDNA structural comparison, we propose an alternative model for the loss of large IR regions in black pine. More cpDNA data from non-Pinaceae conifers are necessary to justify whether the gnetifer or gnepines hypothesis is valid and to generate solid structural evidence for the monophyly of extant gymnosperms.

An integrated map of Oryza sativa L. chromosome 5.

The developments of molecular marker-based genetic linkage maps are now routine. Physical maps based on contigs of large insert genomic clones have been established in several plant species. However, integration of genetic, physical, and cytological maps is still a challenge for most plant species. Here we present an integrated map of rice (Oryza sativa L.) chromosome 5, developed by fluorescence in situ hybridization mapping of 18 bacterial artificial chromosome (BAC) clones or PI-derived artificial chromosome (PAC) clones on meiotic pachytene chromosomes. Each BAC/PAC clone was anchored by a restriction fragment length polymorphism marker mapped to the rice genetic linkage map. This molecular cytogenetic map shows the genetic recombination and sequence information of a physical map, correlated to the cytological features of rice chromosome 5. Detailed comparisons of the distances between markers on genetic, cytological, and physical maps, revealed the distributions of recombination events and molecular organization of the chromosomal features of rice chromosome 5 at the pachytene stage. Discordance of distances between the markers was found among the different maps. Our results revealed that neither the recombination events nor the degree of chromatin condensation were evenly distributed along the entire length of chromosome 5. Detailed comparisons of the correlative positions of markers on the genetic, cytological, and physical maps of rice chromosome 5 provide insight into the molecular architecture of rice chromosome 5, in relation to its cytological features and recombination events on the genetic map. The prospective applications of such an integrated cytogenetic map are discussed.