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Biomedical subjects

Bo Song

Publications and source records attributed to Bo Song.

At least 19 recordsLinked to original sources
PubMed2006

Integration and excision of a newly discovered bacteroides conjugative transposon, CTnBST.

Conjugative transposons (CTns) are major contributors to the spread of antibiotic resistance genes among Bacteroides species. CTnBST, a newly discovered Bacteroides conjugative transposon, carries an erythromycin resistance gene, ermB, and previously has been estimated to be about 100 kbp in size. We report here the locations and sequencing of both of its ends. We have also located and sequenced the gene that catalyzes the integration of CTnBST, intBST. The integrase gene encodes a 377-amino-acid protein that has the C-terminal R-K-H-R-H-Y motif that is characteristic of members of the tyrosine recombinase family of integrases. DNA sequence comparisons of the ends of CTnBST, the joined ends of the circular intermediate, and the preferred site into which the circular form of CTnBST had integrated revealed that the preferred integration site (attB1) contained an 18-bp sequence of identity to the crossover region, attBST, on CTnBST. Although this site was used in about one-half of the integration events, sequence analysis of these integration events revealed that both CTnBST and a miniature form of CTnBST (miniBST) integrated into a variety of other sites in the chromosome. All of the sites had two conserved regions, AATCTG and AAAT. These two regions flanked a 2-bp sequence, bp 10 and bp 11 of the 18-bp sequence, that varied in some of the different sites and sometimes in the attBST sequences. Our results suggest that CTnBST integrates site selectively and that the crossover appears to occur within a 12-bp region that contains the two regions of conserved sequences.

Amino Acid Sequence↗
PubMed2006

Identification of differentially expressed genes in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis.

AIM: To identify genes differentially expressed in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with low potential of lympho-genous metastasis Hca-P and its synogenetic cell line Hca-F with high metastatic potential was constructed by suppression subtracted hybridization (SSH) method. The screened clones of the subtracted library were sequenced and GenBank homology search was performed. RESULTS: Fifteen differentially expressed cDNA fragments of Hca-P were obtained which revealed 8 known genes, 4 expressed sequence tags (ESTs) and 3 cDNAs showed no homology. CONCLUSION: Tumor metastasis is an incident involving multiple genes. SSH is a useful technique to detect differentially expressed genes and an effective method to clone novel genes.

Animals↗
PubMed2006

A europium(III) complex as an efficient singlet oxygen luminescence probe.

A new europium(III) complex, [4'-(10-methyl-9-anthryl)-2,2':6',2"-terpyridine-6,6"-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu(3+), was designed and synthesized as a highly sensitive and selective time-gated luminescence probe for singlet oxygen ((1)O2). The new probe is highly water soluble with a large stability constant of approximately 10(21) and a wide pH available range (pH 3-10), and can specifically react with (1)O2 to form its endoperoxide (EP-MTTA-Eu(3+)) with a high reaction rate constant at 10(10) M(-1) s(-1), accompanied by the remarkable increases of luminescence quantum yield from 0.90% to 13.8% and lifetime from 0.80 to 1.29 ms, respectively. The wide applicability of the probe was demonstrated by detection of (1)O2 generated from a MoO(4)(2-)/H(2)O2 system, a photosensitization system of 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP), and a horseradish peroxidase catalyzed aerobic oxidation system of indole-3-acetic acid (IAA). In addition, it was found that the new probe could be easily transferred into living HeLa cells by incubation with TMPyP. A time-gated luminescence imaging technique that can fully eliminate the short-lived background fluorescence from TMPyP and cell components has been successfully developed for monitoring the time-dependent generation of (1)O2 in living cells.

Catalysis↗
PubMed2006

[Identification of human testicular spermatogenic cells at different stages].

OBJECTIVE: To establish the method to identify human testicular spermatogenic cells. METHODS: Cells were dispersed by mechanic disintegration on testicular biopsy samples of obstructive azoospermic patients. Diff-Quik staining was applied to mixed cell smears. Live cells were observed under inverted microscope equipped with Hoffman modulation contrast optics, and classified according to their morphology. Chromogenic in situ hybridization (CISH) using chromosome 17 centromere probe and anti-c-kit immunocytochemistry staining were applied to classified cell smears. RESULTS: Sertoli cell, primary pachytene spermatocyte (PPS), spermatogonia, round spermatid were the main four round cell groups that can be classified under Hoffman optics. In CISH, Sertoli cell, PPS and spermatogonia displayed 2 centromere signals, while round spermatid and elongated spermatid/sperm displayed 1 centromere signal. In immunocytochemistry staining, PPS and spermatogonia displayed positive staining, while Sertoli cell, round spermatid and sperm displayed negative staining. CONCLUSION: Dispersed human testicular cells displayed different characteristics in live/staining morphology, ploidy analysis, cell surface membrane antigen expression. All of these methods can be chosen to identify human testicular spermatogenic cells at different stages, while cell morphology classifying under Hoffman optics is a simple and effective method for live cell identification.

Adult↗
PubMed2006

Influence of magnesium ions on biofilm formation by Pseudomonas fluorescens.

Mg(2+) can potentially influence bacterial adhesion directly through effects on electrostatic interactions and indirectly by affecting physiology-dependent attachment processes. However, the effects of Mg(2+) on biofilm structure are largely unknown. In this study, Pseudomonas fluorescens was used to investigate the influence of Mg(2+) concentration (0, 0.1 and 1.0mM MgCl(2)) on biofilm growth. Planktonic and attached cells were enumerated (based on DAPI staining) while biofilm structures were examined via confocal laser scanning microscopy and three-dimensional structures were reconstructed. Mg(2+) concentration had no influence on growth of planktonic cells but, during biofilm formation, Mg(2+) increased the abundance of attached cells. For attached cells, the influence of Mg(2+) concentration changed over time, suggesting that the role of Mg(2+) in bacterial attachment is complex and dynamic. Biofilm structures were heterogeneous and surface colonization and depth increased with increasing Mg(2+) concentrations. Overall, for P. fluorescens, Mg(2+) increased initial attachment and altered subsequent biofilm formation and structure.

Bacterial Adhesion↗
PubMed2006

A new terbium(III) chelate as an efficient singlet oxygen fluorescence probe.

A terbium(III) chelate fluorescence probe for detection of singlet oxygen (1O2) in aqueous media, N,N,N1,N1-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-(9''-anthryl)pyridine] tetrakis (acetate)-Tb3+ (PATA-Tb3+), was designed and synthesized. The new chelate is highly water soluble, is almost nonfluorescent, and can specifically react with 1O2 to yield a strongly fluorescent chelate, the endoperoxide of PATA-Tb3+, accompanied by a remarkable increase in the fluorescence quantum yield from 0.46 to 10.5%. The long fluorescence lifetime of the endoperoxide (2.76 ms) allows the probe to be used favorably for time-resolved fluorescence detection of 1O2. The studies of fluorescence property and reaction specificity indicate that the new probe is highly sensitive and selective for 1O2. The probe was used for quantitative detection of 1O2 generated from a MoO4(2-) -H2O2 system to give a detection limit of 10.8 nM. In addition, the good applicability of the probe was demonstrated by the real-time monitoring of the kinetic process of 1O2 generation in a horseradish peroxidase-catalyzed oxidation system of indole-3-acetic acid in a weakly acidic buffer.

Fluorescent Dyes↗
PubMed2006

Effect of partial bladder outlet obstruction on detrusor compliance, excitability and contractility in rats.

OBJECTIVE: Partial bladder outlet obstruction (PBOO) is believed to change the functions of the detrusor, and can lead to an overactive detrusor (OD). The aim of this study was to investigate changes in bladder compliance, excitability and contractility after PBOO in rats. MATERIAL AND METHODS: PBOO was performed for 6 weeks in 20 Wistar rats, 13 of which (OD group) had an OD and seven of which (non-OD group) did not. Simultaneously, 10 rats that underwent sham operations (control group) were also studied. Bladder compliance and cystometric capacity were identified in vivo, but bladder compliance was detected without elimination of bladder capacity. Isolated bladder smooth muscle strip (BSMS) was dissected to determine excitability and contractility. RESULTS: After 6 weeks of PBOO, cystometric capacity and compliance were significantly higher than those in the control group. Compliance was 0.170+/-0.029 and 0.149+/-0.042 ml/cmH2O in the OD and non-OD groups, respectively, compared to 0.037+/-0.017 ml/cmH2O in the control group. The corresponding cystometric capacities were 3.66+/-0.490, 3.08+/-0.590 and 1.14+/-0.225 ml. The excitability in the OD group increased significantly compared to that in the non-OD and control groups. The tension threshold for BSMS contraction was lower in the OD group, and BSMS contracted more frequently at the same tension. The contractility of the BSMS in the OD group decreased significantly compared to that in the non-OD and control groups. CONCLUSIONS: PBOO can cause a higher cystometric capacity and compliance. After PBOO, there is a chance that an OD may develop. When this occurs, the detrusor excitability increases and contractility decreases.

Animals↗
PubMed2006

[Effects of prenatal exposure to low level lead on learning and memory of rats' offspring].

OBJECTIVE: To explore the effects of prenatal exposure to low level lead on learning and memory of rat's offspring. METHODS: The pregnant rats were randomizedly divided into 4 groups and provided with doubly evaporated water in the control group and 125, 250 and 500 mg/L lead acetate solution via drinking water in three exposed groups respectively during the pregnancy. The learning and memory ability of 21-day old and 60-day old offsprings were tested by the Morris water maze and the shuttling and avoiding dark box respectively. RESULTS: The blood and hippocampus lead concentrations of 1-day old and 21-day old offspring in the 3 lead-exposed groups were significantly increased compared with the control group (P < 0.05), while at the period of 60-day old there was no significant difference between them. The time to find the platform in Morris water maze for 21-day old and 60-day old offsprings of the 3 lead in the exposed groups was significantly increased compared with the control group during the 4 days training (P < 0.05). The times of initiative avoiding in the shuttling and avoiding dark box for 21-day old and 60-day old offsprings in the 3 lead-exposed groups were significantly decreased, while the latency of the initiative avoiding and latency of the passive avoiding were significantly increased compared with the control group (P < 0.05). CONCLUSION: Prenatal exposure to low level lead impaired the space learning and memory ability of offsprings of the rats, and this kind of influence will continue till the offspring's maturity.

Animals↗
PubMed2006

[In-vitro differentiation of human testicular round spermatids to elongating spermatids].

OBJECTIVE: To investigate the differentiation of human testicular spermatogenic cells during in vitro culture. METHODS: Testicular cells of obstructive azoospermic patients' testis biopsies were dispersed employing mechanic methods. Then, (1) mixed testicular cells were applied to in vitro culture, and changes of the ratio of elongating spermatids and all round cells were analyzed during mixed cell culture; (2) round spermatids were picked up from the mixed cells employing micromanipulator, followed by differentiation of the isolated round spermatids during microdrop culture. RESULTS: The ratio of the elongating spermatids increased significantly (P < 0.05) after 24 hours of mixed cell culture in HTF medium supplemented with FSH and testosterone. During single round spermatid culture, transformation of the round spermatid to elongating spermatid with newly formed flagellum was observed, and the transformation ratio within 48 hours of microdrop culture was 3.54%. The differentiation of human testicular spermatogenic cells cultured in Vero cell conditioned medium was similar to that cultured in HTF medium. CONCLUSION: Human testicular round spermatids can differentiate to elongating spermatids during in vitro culture. Vero cell conditioned medium does not promote the differentiation of human testicular round spermatids to elongating spermatids.

Animals↗
PubMed2006

[Effects of lead acetate on expression of brain-derived neurotropic factor and P75NTR in rat brain].

OBJECTIVE: To study the effects of lead acetate on the expression of brain-derived neurotropic factor (BDNF) and its receptor P75NTR in rat brain. METHODS: Lead acetate was given to SD rats by intraperitoneal injection (ip) for 5 days at the dosage of 25, 50 and 100mg/kg body weight respectively. The contents of lead in serum, cerebral cortex and hippocampus were measured by atomic absorption spectrophotochemistry. The levels of BDNF mRNA and protein expression in cerebral cortex and hippocampus were observed by RT-PCR and immunohistochemistry, respectively. The levels of P75NTR protein expression in rat brain were measured by immunohistochemistry. RESULTS: Compared with the control, the contents of lead were significantly increased in serum, cerebral cortex and hippocampus in the treatment groups respectively (P < 0.01, P < 0.05). The BDNF mRNA expression in the cerebral cortex (0.52 +/- 0.05, 0.33 +/- 0.03) and hippocampus (0.77 +/- 0.10, 0.92 +/- 0.08) of 50, 100 mg/kg treated groups was significantly higher than that of the control group (0.52 +/- 0.05, 0.33 +/- 0.03), respectively (P < 0.05). The results of immunohistochemistry showed that the area density of BDNF protein in cerebral cortex of every treatment group (0.040 +/- 0.027, 0.048 +/- 0.027, 0.086 +/- 0.040) was significantly increased whereas the average gray value (187.11 +/- 11.15, 180.53 +/- 5.82, 180.15 +/- 8.01) was significantly lower than that of the control (0.026 +/- 0.005, 204.98 +/- 3.45) (P < 0.05, P < 0.01). The area density of BDNF protein in hippocampus of every treatment group was 0.040 +/- 0.027, 0.048 +/- 0.027, 0.086 +/- 0.040, respectively, which was significantly increased compared with the control (0.045 +/- 0.019, P < 0.05). The average gray value of BDNF protein in hippocampus (181.03 +/- 5.16, 171.25 +/- 12.65) of 50, 100 mg/kg were significantly lower than that of the control (198.98 +/- 6.40, P < 0.01). There was no positive expression of P75NTR protein in the control and 25 mg/kg body weight groups. The positive expression of P75NTR protein was detected in 50 and 100 mg/kg body weight groups. CONCLUSION: Lead can increase the BDNF and P75NTR expression in rat brain which might play an important role in the neural damage and repair.

Animals↗
PubMed2005

Self-assembly and micellization of amphiphilic rod-coil block oligomer at the mica-water interface.

In this paper, in situ atomic force microscopy has been used to investigate the micellization and self-assembling structure of an amphiphilic rod-coil block oligomer (EO16OPV) containing a conjugated oligo(phenylene vinylene) dimer and poly(ethylene oxide) at the mica-water interface. It is found that EO16OPV molecules have strong adsorption and aggregation properties on mica. In the wide concentration range from above the critical micelle concentration (cmc) to far below the cmc, a closely packed layer of stripe-like micelles with two preferred orientations can be formed at the mica-water interface. A cylindrical micelle structure for the stripes is proposed. We demonstrate that the stripe-like micelles formed on mica originate from different micellization processes at solution concentrations above and below the cmc. The origins of the strong micellization properties and oriented arrangement of the stripes are also discussed.

Journal Article↗
PubMed2005

Time-dependent four-component relativistic density-functional theory for excitation energies. II. The exchange-correlation kernel.

We extend our previous formulation of time-dependent four-component relativistic density-functional theory [J. Gao, W. Liu, B. Song, and C. Liu, J. Chem. Phys. 121, 6658 (2004)] by using a noncollinear form for the exchange-correlation kernel. The new formalism can deal with excited states involving moment (spin)-flipped configurations which are otherwise not accessible with ordinary exchange-correlation functionals. As a first application, the global potential-energy curves of 16 low-lying omega omega-coupled electronic states of the AuH molecule have been investigated. The derived spectroscopic parameters, including the adiabatic and vertical excitation energies, equilibrium bond lengths, harmonic and anharmonic vibrational constants, fundamental frequencies, and dissociation energies, are grossly in good agreement with those of ab initio multireference second-order perturbation theory and the available experimental data.

Journal Article↗
PubMed2005

Screening differentially expressed genes in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis.

AIM: To screen genes differentially expressed in mouse hepatocarcinoma ascites cell line with high potential of lymphatic metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with high potential of lymphatic metastatic Hca-F and its synogenetic cell line Hca-P with a low metastatic potential was constructed by suppression subtracted hybridization(SSH) method. The screened clones of the subtracted library were sequenced and GeneBank homology search was performed. RESULTS: Fourteen differentially expressed cDNA fragments of Hca-F were obtained with two novel genes. CONCLUSION: SSH is a useful technique to detect differentially expressioned genes and an effective method to clone novel genes.

Animals↗
PubMed2005

Identify lymphatic metastasis-associated genes in mouse hepatocarcinoma cell lines using gene chip.

AIM: In order to obtain lymphogenous metastasis-associated genes, we compared the transcriptional profiles of mouse hepatocarcinoma cell lines Hca-F with highly lymphatic metastasis potential and Hca-P with low lymphatic metastasis potential. METHODS: Total RNA was isolated from Hca-F and Hca-P cells and synthesized into double-stranded cDNA. In vitro transcription double-stranded cDNA was labeled with biotin (i.e. biotin-labeled cRNA, used as the probe). The cRNA probes hybridized with Affymetrix GeneChip(r) MOE430A (containing 22 690 transcripts, including 14 500 known mouse genes and 4 371 ESTs) respectively and the signals were scanned by the GeneArray Scanner. The results were then analyzed by bioinformatics. RESULTS: Out of the 14 500 known genes investigated, 110 (0.8%) were up regulated at least 2(3) fold. Among the total 4 371 ESTs, 17 ESTs (0.4%) (data were not presented) were up regulated at least 2(3) fold. According to the Gene Ontology and TreeView analysis, the 110 genes were further classified into two groups: differential biological process profile and molecular function profile. CONCLUSION: Using high-throughput gene chip method, a large number of genes and their cellular functions about angiogenesis, cell adhesion, signal transduction, cell motility, transport, microtubule-based process, cytoskeleton organization and biogenesis, cell cycle, transcription, chaperone activity, motor activity, protein kinase activity, receptor binding and protein binding might be involved in the process of lymphatic metastasis and deserve to be used as potential candidates for further investigation. Cyclin D1, Fosl1, Hsp47, EGFR and AR, and Cav-1 are selected as the possible candidate genes of the metastatic phenotype, which need to be validated in later experiments. ESTs (data were not presented) might indicate novel genes associated with lymphatic metastasis. Validating the function of these genes is helpful to identify the key or candidate gene/pathway responsible for lymphatic metastasis, which might be used as the diagnostic markers and the therapeutic targets for lymphatic metastasis.

Animals↗
PubMed2005

Preparation of gold colloid monolayer by immunological identification.

The design and initial characterization of the self-assembled gold colloid monolayer by a sandwich structure via the immunological identification are reported. The 13 nm gold colloid nanoparticles and the silicon or quartz substrates have been modified with the mouse polyclonal antibody against hepatitis B virus surface antigen (PAb) and the mouse monoclonal antibody against hepatitis B virus surface antigen (MAb), respectively. They can be linked by a special reaction with their corresponding hepatitis B virus surface antigen (Antigen) as a sandwich structure. Thus, the density of gold nanoparticles self-assembled on the substrate can be readily controlled by the amount of the antigen added. The resulting substrates have been characterized by atomic force microscopy (AFM) and surface-enhanced Raman scattering (SERS) spectroscopy when the gold nanoparticles were modified with SERS-active probe molecules of 4-mercaptobenzoic acid (MBA) after silver enhancement. These data show that the gold nanoparticles are separately fixed onto the substrate and form a uniform monolayer, which possess a set of features that make them very attractive for both basic and applied uses, including roughness, high stability, and biocompatibility.

Animals↗