The air temperature change effect on water quality in the Kvarken Archipelago area

The Kvarken Archipelago is Finland's World Heritage site designated by UNESCO. How climate change has affected the Kvaken Archipelago remains unclear. This study was conducted to investigate this issue by analyzing air temperature and water quality in this area. Here we use long-term historical data sets of 61 years from several monitoring stations. Water quality parameters included chlorophyll-a; total phosphorus; total nitrogen; coliform bacteria thermos tolerant; temperature; nitrate as nitrogen; nitrite-nitrate as nitrogen, and Secchi depth and correlations analysis was conducted to identify the most relevant parameters. Based on the correlation analysis of weather data and water quality parameters, air temperature showed a significant correlation with water temperature (Pearson's correlations = 0.89691, P < 0.0001). The air temperature increased in April (R² (goodness-of-fit) = 0.2109 &P = 0.0009) and July (R² = 0.1207 &P = 0.0155) which has indirectly increased the chlorophyll-a level (e.g. in June increasing slope = 0.39101, R² = 0.4685, P < 0.0001) an indicator of phytoplankton growth and abundance in the water systems. The study concludes that there might be indirect effects of the likely increase in air temperature on water quality in the Kvarken Archipelago, in particular causing water temperature and chlorophyll-a concentration to increase at least in some months.

Frequency stabilization of a terahertz quantum-cascade laser to the Lamb dip of a molecular absorption line

We demonstrate the frequency stabilization of a terahertz quantum-cascade laser (QCL) to the Lamb dip of the absorption line of a D₂O rotational transition at 3.3809309 THz. To assess the quality of the frequency stabilization, a Schottky diode harmonic mixer is used to generate a downconverted QCL signal by mixing the laser emission with a multiplied microwave reference signal. This downconverted signal is directly measured by a spectrum analyzer showing a full width at half maximum of 350 kHz, which is eventually limited by high-frequency noise beyond the bandwidth of the stabilization loop.

Stability and optimal control strategies for a novel epidemic model of COVID-19

In this paper, a novel two-stage epidemic model with a dynamic control strategy is proposed to describe the spread of Corona Virus Disease 2019 (COVID-19) in China. Combined with local epidemic control policies, an epidemic model with a traceability process is established. We aim to investigate the appropriate control strategies to minimize the control cost and ensure the normal operation of society under the premise of containing the epidemic. This work mainly includes: (i) propose the concept about the first and the second waves of COVID-19, as well as study the case data and regularity of four cities; (ii) derive the existence and stability of the equilibrium, the parameter sensitivity of the model, and the existence of the optimal control strategy; (iii) carry out the numerical simulation associated with the theoretical results and construct a dynamic control strategy and verify its feasibility.

A novel bacteriocin BM1029: physicochemical characterization, antibacterial modes and application

AIM

Bacteriocins with antimicrobial activity are considered as potential natural bio-preservatives to control the growth of food spoilage bacteria. The aim of this work was to characterize a novel bacteriocin BM1029 discovered from Lactobacillus crustorum MN047 and evaluate its antibacterial mechanism.

METHODS AND RESULTS

Bacteriocin BM1029 was purified by cation-exchange chromatography and reversed-phase chromatography. Antibacterial activity assay showed that BM1029 is antagonistic against both Gram-positive and Gram-negative bacteria. Furthermore, it was found that BM1029 showed low haemolysis with high stability to the pretreatment with different temperatures, pH and surfactants. Moreover electron microscopy and flow cytometry suggested that BM1029 inhibit indicator strains by damaging the cell envelope integrity. Cell cycle assay suggested that BM1029 arrested cell cycle in R-phase.

CONCLUSION

The novel bacteriocin BM1029 showed high bactericidal activity against Escherichia coli and Staphylococcus aureus through a cell envelope-associated mechanism.

SIGNIFICANCE AND IMPACT OF THE STUDY

Application of BM1029 inhibited the growth of indicator strains on beef meat storage at 4°C suggesting that this bacteriocin is promising to be used as a novel preservative in food processing and preservation.

Spread mechanism and control strategy of social network rumors under the influence of COVID-19

Since the outbreak of coronavirus disease in 2019 (COVID-19), the disease has rapidly spread to the world, and the cumulative number of cases is now more than 2.3 million. We aim to study the spread mechanism of rumors on social network platform during the spread of COVID-19 and consider education as a control measure of the spread of rumors. Firstly, a novel epidemic-like model is established to characterize the spread of rumor, which depends on the nonautonomous partial differential equation. Furthermore, the registration time of network users is abstracted as 'age,' and the spreading principle of rumors is described from two dimensions of age and time. Specifically, the susceptible users are divided into higher-educators class and lower-educators class, in which the higher-educators class will be immune to rumors with a higher probability and the lower-educators class is more likely to accept and spread the rumors. Secondly, the existence and uniqueness of the solution is discussed and the stability of steady-state solution of the model is obtained. Additionally, an interesting conclusion is that the education level of the crowd is an essential factor affecting the final scale of the spread of rumors. Finally, some control strategies are presented to effectively restrain the rumor propagation, and numerical simulations are carried out to verify the main theoretical results.

Frequency and power stabilization of a terahertz quantum-cascade laser using near-infrared optical excitation

We demonstrate a technique to simultaneously stabilize the frequency and output power of a terahertz quantum-cascade laser (QCL). This technique exploits frequency and power variations upon near-infrared illumination of the QCL with a diode laser. It does not require an external terahertz optical modulator. By locking the frequency to a molecular absorption line, we obtain a long-term (one-hour) linewidth of 260 kHz (full width at half maximum) and a root-mean-square power stability below 0.03%. With respect to the free-running case, this stabilization scheme improves the frequency stability by nearly two orders of magnitude and the power stability by a factor of three.

[Effect of moxibustion pretreatment at different time on ovarian function in rats with dimini-shed ovarian reserve]

OBJECTIVE

To observe the effect of moxibustion pretreatment at different time on serum hormone levels in diminished ovarian reserve (DOR) rats, so as to explore its protective mechanisms.

METHODS

Forty female SD rats were randomly divided into control, model, moxibustion-1 (moxibustion was given 4 weeks before modeling), moxibustion-2 (moxibustion was given 2 weeks before modeling and 2 weeks from the 1st day on after modeling ) and moxibustion-3 (moxibustion was given 4 weeks from the 1st day on after modeling) groups (n=8 rats in each group). The DOR model was established by gavage of Tripterygium Glycosides (75 mg/kg) once daily for 14 days. Grain-moxibustion was applied to "Shenshu" (BL23) and "Guanyuan" (CV4) for 7 cones, 5 times a week for 4 weeks. The body weight and the ovary weight were recorded for calculating the ovarian index. The levels of serum anti-mullerian hormone (AMH), follicle stimulating hormone (FSH), estradiol (E2), androgen (T) and dehydroepiandrosterone (DHEA) were detected by ELISA.

RESULTS

After modeling, ovarian index and serum AMH levels were obviously decreased (P<0.05), and the levels of serum FSH, E2, T and DHEA were significantly increased in contrast with the control group (P<0.05). Following intervention and compared with the model group, the serum FSH and DHEA levels of each moxibustion group were significantly reduced (P<0.05), the AMH levels significantly increased and E2 and T contents significantly decreased in the moxibustion-2 and moxibustion-3 groups (P<0.05). The serum FSH, E2 and T contents in moxibustion-2 group were obviously lower than those of the moxibustion-1 and moxibustion-3 groups (P<0.05).

CONCLUSION

Moxibustion pre-treatment can improve ovarian reserve function in DOR rats, while the effect is different with different intervention time, and the best intervention time is pre-occurrence and early stage of DOR.

[Clinical features of primary tracheobronchial pulmonary amyloidosis]

Objective: To analyze the clinical features of primary tracheobronchial pulmonary amyloidosis (PTBA). Methods: The records of 11 patients with PTBA diagnosed by pathology from January 2002 to June 2018 in Xiangya Hospital of Central South University were retrospectively reviewed, including clinical manifestations, laboratory and imaging examination, bronchoscopic manifestations and therapies. Meanwhile, PTBA was staged based on the severity and extent of lesion under bronchoscopy. Results: The most common clinical symptoms were cough and expectoration followed by shortness of breath and hemoptysis. Chest computed tomography (CT) revealed pulmonary infection (4/11), pulmonary nodules and masses (5/11), interstitial lesions (2/11), tracheal bronchial wall thickening (5/11) or airway stenosis (4/11). Bronchoscopy showed mucosal hypertrophy (8/11), nodular bulge (3/11), and luminal stenosis (6/11). According to the lesion involvement, 1 case only involved the lungs, 10 cases involved the trachea and/or bronchus, with (8/10) or without (2/10) lung lesions. According to the bronchoscopic staging, 2 cases (2/10) in the stage Ⅰ, lesions were limited; 2 cases (2/10) in the stage Ⅱ, lesions were diffuse; 6 cases (6/10) in the stage Ⅲ, diffuse lesions with stenosis. Conclusions: PTBA is a rare disease of the respiratory system, with unspecific clinical manifestations and diverse pulmonary imaging findings; airway mucosal hypertrophy and nodular bulging can be seen under bronchoscopy. Patients with advanced stage may present with airway stenosis.

Wideband, high-resolution terahertz spectroscopy by light-induced frequency tuning of quantum-cascade lasers

Near-infrared optical excitation enables wideband frequency tuning of terahertz quantum-cascade lasers. In this work, we demonstrate the feasibility of the approach for molecular laser absorption spectroscopy. We present a physical model which explains the observed frequency tuning characteristics by the optical excitation of an electron-hole plasma. Due to an improved excitation configuration as compared to previous work, we observe a single-mode continuous-wave frequency coverage of as much as 40 GHz for a laser at 3.1 THz. This represents, for the same device, a ten-fold improvement over the usually employed tuning by current. The method can be readily applied to a large class of devices.

Isolation, identification and characterization of lignin-degrading bacteria from Qinling, China

AIMS

Lignin is an aromatic heteropolymer forming a physical barrier and it is a big challenge in biomass utilization. This paper first investigated lignin-degradation bacteria from rotten wood in Qinling Mountain.

METHODS AND RESULTS

Nineteen potential strains were selected and ligninolytic enzyme activities were determined over 84 h. Strains that had higher enzyme activities were selected. Further, the biodegradation of wheat straw lignin and alkali lignin was evaluated indicating that Burkholderia sp. H1 had the highest capability. It was confirmed by gel permeation chromatography and field emission scanning electron microscope that alkali lignin was depolymerized into small fragments. The degraded products were analysed using gas chromatography-mass spectrometry. The total ion chromatograph of products treated for 7 days showed the formation of aromatic compounds, an important intermediate from lignin degradation. Interestingly, they disappeared in 15 days while the aldehyde and ester compounds increased.

CONCLUSIONS

The results suggest that the lignin-degrading bacteria are abundant in rotten wood and strain H1 has high potential to break down lignin.

SIGNIFICANCE AND IMPACT OF THE STUDY

The diversity of lignin-degrading bacteria in Qinling Mountain is revealed. The study of Burkholderia sp. H1 expands the range of bacteria for lignin degradation and provides novel bacteria for application to lignocellulosic biomass.

Vector bright solitons associated with positive coherent coupling via Darboux transformation

Describing coherently coupled and orthogonally polarized waveguide modes in the Kerr medium, vector bright solitons associated with positive coherent coupling are studied in this paper. Some conserved quantities and infinitely many conservation laws are computed, and the existence of Lax pair indicates the integrability of the two-coupled nonlinear Schrödinger system with positive coherent coupling. Performing the iterative algorithm of Darboux transformation, we present formulas of one-, two-, and even N-soliton solutions. With appropriate choices of the phase parameters, collision mechanisms of vector bright solitons (of single-hump, double-hump, or flat-top profiles) are displayed, which show the elastic collision under the combined influences of group velocity dispersion, self-phase modulation, cross-phase modulation, and positive coherent coupling.

Soliton behavior for a generalized mixed nonlinear Schrödinger model with N-fold Darboux transformation

A spectral problem, the x-derivative part of which is a simple generalization of the standard Ablowitz-Kaup-Newell-Segur and Kaup-Newell spectral problems, is presented with its associated generalized mixed nonlinear Schrödinger (GMNLS) model. The N-fold Darboux transformation with multi-parameters for the spectral problem is constructed with the help of gauge transformation. According to the Darboux transformation, the solution of the GMNLS model is reduced to solving a linear algebraic system and two first-order ordinary differential equations. As an example of application, we list the modulus formulae of the envelope one- and two-soliton solutions. Note that our model is a generalized one with the inclusion of four coefficients (a, b, c, and d), which involves abundant NLS-type models such as the standard cubic NLS equation, the Gerdjikov-Ivanov equation, the Chen-Lee-Liu equation, the Kaup-Newell equation, and the mixed NLS of Wadati and/or Kundu, among others.

[A study on the veterinary antibiotics contamination in groundwater of Jiaxing]

Liquid chromatography and tandem mass (LC-MS/MS) followed with solid-phase extraction (SPE) was developed for simultaneously determining four classes (tetracyclines, quinolones, macrolides and sulfonamides) of ten commonly used veterinary antibiotics in groundwater of Jiaxing city, an important pig breeding base in the Yangtze River Delta region. Samples were taken from 10 typical rural river sections and 21 main urban river sections. Results revealed severe pollution existed in the rural river environment. The total concentration of ten antibiotics was as high as 65.6-467.0 ng x L(-1), among which tetracyclines and sulfonamides respectively ranged in 40.8-253.0 ng x L(-1) and undetected (nd)- 165.0 ng x L(-1), macrolides and quinolones respectively ranged in 3.1-14.68 ng x L(-1) and nd-14.54 ng x L(-1). By comparison, the pollution level in urban rivers was much lower. The total concentration of ten antibiotics ranged in 20.1 ng x L(-1) to 61.2 ng x L(-1), among with tetracyclines varied from undetected to 44.0 ng x L(-1), while sulfonamides, macrolides and quinolones were respectively below 2.7 ng x L(-1), 6.3 ng x L(-1) and 21.6 ng x L(-1).

Nonautonomous motion study on accelerated and decelerated solitons for the variable-coefficient Lenells-Fokas model

In this paper, the nonautonomous Lenells-Fokas (LF) model is studied with the bilinear method and symbolic computation. Such analytical solutions of the nonautonomous LF model as one-soliton, two-soliton, and earthwormons are derived. Nonautonomous characteristics are then symbolically and graphically investigated, and it is finally found that the soliton velocity is time-dependent, and there exist soliton accelerating and decelerating motions. Further, two necessary conditions for the occurrence of earthwormon acceleration and deceleration (and their alternation) are pointed out.

Lateral distributed-feedback gratings for single-mode, high-power terahertz quantum-cascade lasers

We report on terahertz quantum-cascade lasers (THz QCLs) based on first-order lateral distributed-feedback (lDFB) gratings, which exhibit continuous-wave operation, high output powers (>8 mW), and single-mode emission at 3.3-3.4 THz. A general method is presented to determine the coupling coefficients of lateral gratings in terms of the coupled-mode theory, which demonstrates that large coupling strengths are obtained in the presence of corrugated metal layers. The experimental spectra are in agreement with simulations of the lDFB cavities, which take into account the reflective end facets.

Vector bright soliton behaviors associated with negative coherent coupling

With the introduction of an auxiliary function, a genuine bilinear system (in contrast to the published trilinear forms) is obtained for the two-coupled nonlinear Schrödinger equations with negative coherent coupling in the optical fiber communications. With symbolic computation, degenerate and nondegenerate vector solitons are derived associated with the corresponding phase-parameter constraints. In virtue of asymptotic analysis and graphical simulation, vector solitons of the single-hump, double-hump, or flat-top profiles are displayed, and the collision mechanisms of such vector solitons are revealed as well; namely, the collisions among degenerate solitons and among nondegenerate solitons are both elastic. The only possible inelastic collision, the collision in the degenerate-nondegenerate case, is pointed out, where a degenerate soliton interacts with a nondegenerate one. Results in this paper may be useful for the optical switching with the combined effects of self-phase modulation, cross-phase modulation, and negative coherent coupling.

Integrability study on a generalized (2+1)-dimensional variable-coefficient Gardner model with symbolic computation

Gardner model describes certain nonlinear elastic structures, ion-acoustic waves in plasmas, and shear flows in ocean and atmosphere. In this paper, by virtue of the computerized symbolic computation, the integrability of a generalized (2+1)-dimensional variable-coefficient Gardner model is investigated. Painlevé integrability conditions are derived among the coefficient functions, which reduce all the coefficient functions to be proportional only to γ(t), the coefficient of the cubic nonlinear term u(2)u(x). Then, an independent transformation of the variable t transforms the reduced γ(t)-dependent equation into a constant-coefficient integrable one. Painlevé test shows that this is the only case when our original generalized (2+1)-dimensional variable-coefficient Gardner model is integrable.

[Epidemiological and molecular characterization of seasonal influenza A/H3N2 viruses circulating in Shenzhen, 2005 - 2007]

OBJECTIVE

To determine the epidemiological characteristics of seasonal influenza in Shenzhen from 2005 to 2007 and the molecular variation of HA1 domain of influenza H3N2 viruses.

METHODS

The consultation rate for influenza-like illness (ILI) were calculated weekly for indicating the influenza activities (the Shenzhen Influenza Surveillance System mainly consisted of 16 institutions with 9 hospitals, 6 districts and one municipal centers of disease control and prevention). Pharyngeal swabs from the cases of ILI, which were collected during 2005 to 2007 from the city-wide and quality-controlled surveillance network, were used to propagate the viruses. The HA1 region of the influenza A/H3N2 viruses were detected by RT-PCR and sequenced subsequently. The analyses of pairwise amino acid variations, genetic clustering and phylogenetics was performed.

RESULTS

The activity levels of influenza showed certain changes during each year from 2005 to 2007, and there were summer peaks from May to July in 2006 and 2007. The positive rates of influenza virus were 4.78% (114/2385), 5.77% (212/3674) and 12.12% (343/2831) from 2005 to 2007 respectively. The weekly isolating rates changed accordingly with the trend of the percentages of ILI. The proportions of influenza H3N2 virus were 25.46% (28/114) and 2.83% (6/212) in 2005 and in 2006 respectively, but the proportion increased to 62.68% (215/343), which indicated that H3N2 virus became the predominant strain in 2007. Phylogenetic clustering analysis of influenza H3N2 virus revealed that there were 5 clades. The viruses which were isolated in 2005 contained in the clade I and II, the viruses in 2006 were comprised in clade III, and clade IV and V included the viruses isolated in 2007. Although the stem of cladogram developed with one accord of the time isolated viruses, the viruses which were similar to vaccine strains had circulated in Shenzhen before a given strain was determined as vaccine strain by WHO. It was also noticed that more amino acid changes at antigenic sites, especially at sites A and B in the H3N2 viruses, were found in 2007 than that in 2005 and in 2006. But the sequences at the receptor-binding sites and disulphide bond sites were conserved and no new circulating strain for genetic reassortment had been found in the period.

CONCLUSION

Shenzhen might be one of areas where the ongoing genetic drift of influenza H3N2 viruses appeared earlier in China. The changes of influenza H3N2 virus showed the active status in the population. The results suggested that monitoring seasonal influenza viruses by sequence analysis could provide important and timely information on the appearance of strains with epidemiologic significance.

Radiation-induced gene translation profiles reveal tumor type and cancer-specific components

The microarray analysis of total cellular RNA is a common method used in the evaluation of radiation-induced gene expression. However, profiling the cellular transcriptome does not take into account posttranscriptional processes that affect gene expression. To better define the genes whose expression is influenced by ionizing radiation, we used polysome-bound RNA to generate gene translation profiles for a series of tumor and normal cell lines. Cell lines were exposed to 2 Gy, polysome-bound RNA isolated 6 hours later, and then subjected to microarray analysis. To identify the genes whose translation was affected by radiation, the polysome-bound RNA profiles were compared with their corresponding controls using significance analysis of microarrays (<1% false discovery rate). From the statistically significant genes identified for each cell line, hierarchical clustering was performed by average linkage measurement and Pearson's correlation metric. Ingenuity Pathway Analysis was used for distributing genes into biological networks and for evaluation of functional significance. Radiation-induced gene translation profiles clustered according to tissue of origin; the cell lines corresponding to each tissue type contained a significant number of commonly affected genes. Network analyses suggested that the biological functions associated with the genes whose translation was affected by radiation were tumor type-specific. There was also a set of genes/networks that were unique to tumor or normal cells. These results indicate that radiation-induced gene translation profiles provide a unique data set for the analysis of cellular radioresponse and suggest a framework for identifying and targeting differences in the regulation of tumor and normal cell radiosensitivity.

Radiation-Induced Changes in Gene Expression Involve Recruitment of Existing Messenger RNAs to and away from Polysomes

Although ionizing radiation has been shown to influence gene transcription, little is known about the effects of radiation on gene translational efficiency. To obtain a genome-wide perspective of the effects of radiation on gene translation, microarray analysis was done on polysome-bound RNA isolated from irradiated human brain tumor cells; to allow for a comparison with the effects of radiation on transcription, microarray analysis was also done using total RNA. The number of genes whose translational activity was modified by radiation was approximately 10-fold greater than those whose transcription was affected. The radiation-induced change in a gene's translational activity was shown to involve the recruitment of existing mRNAs to and away from polysomes. Moreover, the change in a gene's translational activity after irradiation correlated with changes in the level of its corresponding protein. These data suggest that radiation modifies gene expression primarily at the level of translation. In contrast to transcriptional changes, there was considerable overlap in the genes affected at the translational level among brain tumor cell lines and normal astrocytes. Thus, the radiation-induced translational control of a subset of mRNAs seems to be a fundamental component of cellular radioresponse.

[CCD-array detection-flow injection analysis of oligomeric: proanthocyanidins in health food]

A flow-injection-CCD array detection spectrophotometry for the determination of oligomeric proanthocyanidin (OPC) in health foods was developed in the present paper, based on the reaction that OPC can form red anthocyanidin in hydrochloric acid medium with ferric ion as a catalytic agent. The absorption spectrum of OPC was scanned and the absorbance at 545 nm was determined by flow injection with CCD-array detector. The influencing factors of the chromogenic reaction and parameters of the flow injection analysis were optimized. There is a good linear relationship between the absorbances and the concentrations of OPC in the range of 0.010-0.20 mg x mL(-1). The detection limit of the method was 5 microg x mL(-1). The recoveries were 82.47%-98.18% with the relative standard deviation (RSD) of 1.5%-4.9%. The proposed method is sensitive, accurate and rapid with the sampling frequency of 10 samples-h(-1) and suitable for the determination of OPC in the health food.

Transcriptional signature of flavopiridol-induced tumor cell death

Flavopiridol has been shown to inhibit the proliferation of a variety of human tumor cells and is currently undergoing clinical evaluation in cancer treatment. Although the antiproliferative effect of flavopiridol has been attributed to the inhibition of cyclin-dependent kinases 2 and 4, recent reports indicate that the mechanism responsible for the cell death induced by this agent is more complex. To provide insight into the molecular processes mediating flavopiridol-induced cytotoxicity and to investigate the availability of markers indicative of its activity, we have applied cDNA microarray technology. Gene expression profiles were determined for four human tumor cell lines (prostate carcinomas PC3 and DU145 and gliomas SF359 and U251) following exposure to selected concentrations of flavopiridol. Treatment of these cell lines with a concentration of flavopiridol sufficient to reduce survival to 10% resulted in the identification of a set of 209 genes, the expression of which were altered in each of the cell lines. This common set of 209 gene expression changes suggested that flavopiridol-induced cell death can be defined in terms of a specific transcriptome. The flavopiridol death transcriptome consisted primarily of down-regulated genes; however, there were also a significant number of genes with increased expression. Whereas causal relationships were not established, these data suggest molecular events/processes that may be associated with flavopiridol-induced tumor cell death. Moreover, the identification of a set of gene expression changes in four human tumor cell lines suggests that such a transcriptome may be applicable to investigations of flavopiridol pharmacodynamics.

Microarray analysis in clinical oncology: pre-clinical optimization using needle core biopsies from xenograft tumors

Background

DNA microarray profiling performed on clinical tissue specimens can potentially provide significant information regarding human cancer biology. Biopsy cores, the typical source of human tumor tissue, however, generally provide very small amounts of RNA (0.3–15 μg). RNA amplification is a common method used to increase the amount of material available for hybridization experiments. Using human xenograft tissue, we sought to address the following three questions: 1) is amplified RNA representative of the original RNA profile? 2) what is the minimum amount of total RNA required to perform a representative amplification? 3) are the direct and indirect methods of labeling the hybridization probe equivalent?

Methods

Total RNA was extracted from human xenograft tissue and amplified using a linear amplification process. RNA was labeled and hybridized, and the resulting images yielded data that was extracted into two categories using the mAdb system: "all genes" and "outliers". Scatter plots were generated for each slide and Pearson Coefficients of correlation were obtained.

Results

Results show that the amplification of 5 μg of total RNA yields a Pearson Correlation Coefficient of 0.752 (N = 6,987 genes) between the amplified and total RNA samples. We subsequently determined that amplification of 0.5 μg of total RNA generated a similar Pearson Correlation Coefficient as compared to the corresponding original RNA sample. Similarly, sixty-nine percent of total RNA outliers were detected with 5 μg of amplified starting RNA, and 55% of outliers were detected with 0.5 μg of starting RNA. However, amplification of 0.05 μg of starting RNA resulted in a loss of fidelity (Pearson Coefficient 0.669 between amplified and original samples, 44% outlier concordance). In these studies the direct or indirect methods of probe labeling yielded similar results. Finally, we examined whether RNA obtained from needle core biopsies of human tumor xenografts, amplified and indirectly labeled, would generate representative array profiles compared to larger excisional biopsy material. In this analysis correlation coefficients were obtained ranging from 0.750–0.834 between U251 biopsy cores and excised tumors, and 0.812–0.846 between DU145 biopsy cores and excised tumors.

Conclusion

These data suggest that needle core biopsies can be used as reliable tissue samples for tumor microarray analysis after linear amplification and either indirect or direct labeling of the starting RNA.

Genotype and allele frequency of the variable number tandem repeat polymorphism in the VNTR6-1st of the of human telomerase reverse transcriptase (hTERT) gene in Chinese population

The variable number of tandem repeat (VNTR) polymorphism in the intron 6 of the human telomerase reverse transcriptase(hTERT) was investigated. Seven alleles of 18, 20, 21, 22, 23, 26 and 35 repeats of the 36 bp VNTR6-1st and 14 genotypes were identified among 210 unrelated healthy Chinese individuals (Han people) living in Beijing. The 20, 22 and 35 repeats were the most frequent alleles which accounted for 94.76% of the total alleles observed. The allele frequency of the Chinese population showed no difference with that of the Korea population living in Pusan except for allele of 35 repeats. But the 5' flanking region of VNTR6-1st polymorphic sequence of the Chinese population included a 53-bp insert compared with that of korea population except for some alleles of 22 repeats.

[Isolation and characterization of a novel radiation-resistant rod-shaped bacterium]

A novel radiation-resistant bacterium was isolated from soil of lake bank in Beijing. The bacterium produced orange-pigmented colonies and formed rod-shaped cells that stained gram negative alike the Deinobacter grandis previously described by Japan's scientist. It was found with electron microscopy that the isolate is of 0.6 microm - 1.6 microm size and has a 30-40 nm thickness of cell wall, being slightly larger and thicker than the Deinobacter grandis. There was a difference in the concentration and molecule weight of catalase between the isolate and the Deincoccus radiodurans R1. The deoxyribonucleic acid guanine plus cytosine (G + C) base ratio was 70.7 mol%. 16S RNA gene sequencing also showed that this rod-shaped bacterium possessed a high homology with the Deinobacter grandis, suggesting that it might be classified into the genus Deinobacter and constitute a new species in this genus.

Deinococcus radiodurans CatB Gene Cloning and Expression in Escherichia coli

A 1 611 bp length complete coding sequence of the catalase (Cat) was obtained through bioimformatical analysis of the database of D.radiodurans genome, and then was amplified from D. radiodurans genomic DNA by polymerase chain reaction. The amplified gene was cloned into pKK223-3 vector and transformed into E.coli UM2, a Cat-deficient mutant. Staining of non-denaturing polyacrylamide gels for Cat activity demonstrated that pKK223-3 insert encoded a Cat that co-migrated with the CatB found in D.radiodurans cell lysates. Expression of CatB gene from D.radiodurans in E.coli UM2 restored the resistance to H(2)O(2) at low concentrations.

[A short tandem repeat polymorphism in the inducible nitric oxide synthase gene in Chinese population]

Polymorphism of the (CCTTT)n repeat, a short tandem repeats (STR) located in promoter region of the inducible nitric oxide synthase (iNOS) gene, was analyzed in a total of 316 Chinese healthy subjects. Twelve alleles and forty-nine genotypes were identified. Three alleles that had not been reported previously, namely 17-repeats, 18-repeats and 19-repeats, were found in Chinese population. Mendelian inheritance of the allele in a family composed of three generations was determined. Some of the observed allele frequency of this STR locus in Chinese differed significantly from that of Caucasians in England.

[Studies of protective effect of SOD on damage of human RBCs stored at 4 degrees C]

AIM

To investigate the mechanism of protective effect of SOD (superoxide dismutase) on damage of RBCs stored at 4 degrees C, the studies of erythrocyte glucose and energy metabolism were performed.

METHODS

whole blood collected from healthy donors and stored at 4 degrees C in ACD, GMA and SOD solutions. Before and post storage, some parameters were assayed. Standard methods were used for the in vitro tests. The 24-hour in vivo recoveries were measured by FTTC (Fluorescein 5-isothiocyanate) from SIGMA Company.

RESULTS

All parameters of red blood cell glucolysis rate without oxygen condition, ATP, PK (pyruvic kinase) and 24 h recoveries level were 86.2%, 56.4%, 64.3% and 86.2% of normal respectively stored in SOD solution at 4 degrees C for 75 days, distinctly more than in ACD and GMA groups at 75 days stored. The 24 h recovery at 75d in group SOD was near the recovery at 42d in group GMA.

CONCLUSION

Whole blood in SOD solution can be stored satisfactorily for 75 days at 4 degrees C, and furnished theoretical evidence for RBCs survival.

Genotype and allele frequency of the 27-bp tandem repeat polymorphism in the endothelial nitric oxide synthase gene in Chinese population

Genotype and allele frequency of the polymorphic 27-bp repeat, a variable number of tandem repeats (VNTR) located in intron 4 of the endothelial nitric oxide synthase gene, were analyzed in 316 healthy Chinese individuals. Four genotypes, namely 6/5-repeats heterozygous, 5/5-repeats homozygous, 5/4-repeats heterozygous and 4/4-repeats homozygous, were identified. Both observed genotype and allele frequencies of this VNTR in Chinese were similar to those of Japanese, while the 4/4-repeats genotype differed significantly from that of Caucasians in Spain, and all ones did from those of African-American in United States.

[Study of quinolones resistance in Escherichia coli, Staphylococcus aureus and Pseudomonas areuginosa]

OBJECTIVE

To investigate the factors of quinolone-resistance mediating in Escherichia coli(E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas areuginosa(P. areuginosa) and examine the characteristic changes and quinolones resistance of these bacteria after exposing them to quinolones, dye-materials, and ultraviolet respectively.

METHODS

The agar plate inoculating on surface and tube broth two-fold dilution methods were adopted.

RESULTS

Quinolone-resistance was mainly mediated by repeated exposure of the bacteria to low level concentration of quinolone. No quinolone-resistance was found after exposure of the bacteria to ultra-violet and dye materials such as Ethidium bromide and Acry-orange. Among the three kinds of bacteria, E. coli tended to have stable high level of quinolone- resistance(MICs > or = 256 mg/L). S. aureus acquired mediate level of quinolone-resistance(MICs < or = 32 mg/L). P. aeruginosa acquired a high but not stable level(MICs > or = 256 mg/L) of resistance. These bacteria were cultured in the concentration of 1/2 x MIC, 1 x MIC, 2 x MIC, 4 x MIC, 5 x MIC ciprofloxacin, and were compared with those cultured in the same concentration of sparfloxacin and cefotaxime. After being affected by ciprofloxacin, the E. coli underwent apparent morphologic changes, such as becoming wider(2-3 times), longer(10-30 times), thread-like, and fewer in number. These changes were consistent with the increase of quinolone concentrations. The morphologic changes in P. aeruginosa and S. aureus were not so obvious as those in E. coli. Sparfloxacin and cefotaxime mainly led to the decrease in the numbers of bacteria. When the concentration of Sparfloxacin and cefotaxime were 4 x MICs, the changes of P. aeruginosa and S. aureus were less obvious.

CONCLUSION

The bacteria's quinolone-resistance is mainly induced by the quinolone itself. The quinolone-resistance is more likely occur in E. coli than in P. aeruginosa and S. aureus. After exposure of the bacteria to ciprofloxacin, E. coli might have most apparent morphologic changes and occurrence resistance.

[The preparation of norA gene probe in Staphylococcus aureus]

OBJECTIVE

To prepare norA gene probe for studies on the mechanism of resistance to fluoroquinolones mediated by norA gene in S. aureus.

METHODS

The Dig-labeled norA gene probe was made by PCR.

RESULTS

This method is simple and feasible. We have got a lot of probes in a short time. The sensitivity of norA gene probe is high; the probe is secure, easy to use and can be stored for a long time.

CONCLUSION

The probe is applicable to further studies on the mechanism of resistance to fluoroquinolones mediated by norA in S. aureus.

[Study on apoptosis of human gastric adenocarcinoma cell SGC-7901 induced by aining in vitro and the cell cycle]

OBJECTIVE

To study the inducing apoptosis effect of Aining on human gastric adenocarcinoma cell in vitro.

METHODS

Agarose gel electrophoresis (AGE) and flow cytometry (FMC) techniques were adopted to study the inducing apoptosis effect of Ainging on the human gastric adenocarcinoma cell.

RESULTS

The human gastric adenocarcinoma cell's DNA was digested into fragments which gave rise to a characteristic "DNA Ladder" on agarose gel electrophoresis, while the percentage of apoptotic cells was 43.5%. But the blank group had neither DNA ladder, nor apoptotic peak. Cell cycle analysis showed that the proliferation index was 33.7% after the human gastric adenocarcinoma cells treated with Aining, and there was no cell phase specialty.

CONCLUSION

Aining can induce human gastric adenocarcinoma cell apoptosis in vitro.

The tree shrew apolipoprotein C-I cDNA: sequence and its expression

A rabbit anti-serum to tree shrew apolipoprotein C-I (apo C-I) was used to screen an expression cDNA library constructed by us from tree shrew (TS) liver tissue. Two apo C-I cDNA clones were obtained. The longer one consists of 380 nucleotides, including 21 bp and 95 bp at the 5' and 3' end of the non-translated regions respectively, and a 264-bp fragment in an open reading frame encoding 88 amino acids prepropeptide which contains 26 amino acids of signal peptide and a mature protein (62 amino acids). Comparing the amino-acid sequence deduced from this cDNA with those of the published mammalian apo C-Is reveals that it shared some structural similarity with rat, mouse and dog apo C-I, but it had 5 more amino acids than that of human and baboon. The expression of apo C-I mRNA in 8 different tissues were also assayed with Northern blot. The results demonstrated that liver had the highest expression, intestine had much less expression and no expression in other tissues, which is much different from human and other species. This study has laid down a good foundation for further studying on the function and the stucture of tree shrew apo C-I gene.

[The hygienic examination and quality research of Chinese crude drug scorpion]

We selected the method of hygienic test to determinate the infection of colibacilli, salmonelli, mixed bacteria, mould fungus and yeasts on Chinese crude drug scorpion from 29 commerical samples in different storaged period, habitats and commerical standard. The results showed there were not colibacilli and salmonelli in all 29 samples, but infectious mixed bacteria rate is 100%, which is 2.1 times more than salty scorpion in 29 tested samples, and the infectious fungi rate is 72.4%. The fungi of salty scorpion is 15% more than fresh scorpion. The quantity of infected yeasts on salty scorpion is much more than scorpion. There are 4 species of fungi such as Alternaria neesex Wallroth, Aspergillus fumigatus Fresenius, Nocarcia sp. and Tricophyton violaceum Sabouraud. Because of infectious pathogenic bacteria rate is so high, we suggest to increase the item of hygienic test to control the quality of crude drug scorpion and strengthen the administration of commerical drugs, so as to reduce the contaminative condition.

National survey on prevalence of cancer pain

OBJECTIVE

To collect nationwide basic data about cancer related pain.

METHODS

Sixty cancer patients in each province were randomly selected to participate in this survey. The subjects represented all stages of cancer, tumor sites, and different demographic characteristics. Two self-designed structured questionnaires including reasons, types of pain and pain management were used by patients and physicians respectively. Subjects were asked to report whether he/she had experienced any type of cancer related pain and filled out the equivalent questionnaire. The severity of pain was assessed by using "visual analogue scale". Original data input and analysis were using EPI-INFO software package.

RESULTS

The result showed that 61.6% (958/1555) of patients had different types of cancer related pain. Majority of pain (85.1%) were caused by advanced cancer. The major reasons (64.4%) for poor management or impedimental factors of pain care are due to patient including over-concern on opioid analgesic addiction, reluctance to report pain or refused to use opioid analgesic until at times when pain is intolerable; 26.8% belonged to physician's reasons including fear to cause addiction on opioid and lack of knowledge about cancer pain management; 16.2% are due to lack of different kinds of opioid analgesic for use and 16.1% belonged to drug regulation.

CONCLUSIONS

The results showed that majority of patients (61.6%) had different types of cancer related pain. In most of patients, cancer pain was relieved when they were treated. The major reason for under-treatment or impeded factors for effective relief of cancer pain was fear of opioid addiction by both medical professionals and patients.

[Expression of recombinant human Flt3 ligand in Escherichia coli and its purification and characterization]

OBJECTIVE

To establish a highly efficient expression system of recombinant human Flt3 ligand (rhFL) in E. coli and a suitable purification method of the expressed products.

METHOD

Human FL encoding cDNA was introduced into pProEXHT plasmid to express a 6 x His-FL fusion protein in E. coli. The fusion protein expressed in inclusion body was isolated, solubilized and refolded, and then purified by chromatography on a metal-chelating affinity column (MCAC). Its activity was detected by stimulating the proliferation of CD(34)(+) cells.

RESULT

The amount of rhFL expressed was about 15% of total bacterial proteins and the purity of rhFL was 90% after MCAC. The combination of rhFL, granulocyte colony-stimulating factor and erythropoietin could stimulate CD(34)(+) cells to a 400 fold expansion.

CONCLUSION

The purified rhFL had a potent activity to stimulate hematopoietic stem cells to expanse in vitro.

[The HVR genotypes and their relationship with the resistance of methicillin-resistant staphylococci]

OBJECTIVE

To investigate the HVR-PCR genotype of methicillin-resistant Staphylococci in local hospitals and compare it with the antibiograms, with aview to selecting effective antibacterial agents, moreover, to discuss preliminarily its role in molecular epidemiology.

METHODS

The minimal inhibitory concentrations(MICs) of 86 MRSA, 10 MRSE(Mc'S. epidemidis), 5 MSSE(Mc'S. epidemidis), 8 MRSH(Mc'S. haemolyticus) and 5 MSSH(Mc'S. haemolyticus) clinical isolates collected from 4 local hospitals were tested by serial two-fold agar dilution method; their DNA were extracted by moved basic lytic method, whose polymerase chain reaction(PCR) products amplified, based on the size of mec-associated hypervariable region(HVR) were analyzed by PAG vertical and agarose gel electrophoresis.

RESULTS

MRSA, MRSE and MRSH were grouped into 4, 3 and 2 HVR genotypes respectively according to the size of the PCR products. The PCR products amplified from 9 of 10 MRSE isolates were the same as the products amplified from MRSA isolates. MRSA strains in this study were mainly HVR genotypes A and D, which accounted for 52.32% and 39.53%; Genotypes B and C were the most multi-drug resistant, but genotype D was multi-sensitive. The I genotype of MRSE was multi-drug resistant, but its genotype III was multi-drug sensitive. The genotype a of MRSH was more resistant than genotype b.

CONCLUSION

These results suggest that HVR-PCR genotype method is an easy and fast method for epidemiological investigation of nosocomial infections caused by MRSA, and it is helpful for clinical selection of antibacterial agents. This method can compare the mec determinants of MRSA and Mc'CNSt isolates and hence to search for the origin of the mec determinant.

[Culture and identify the endothelial cells of human umbilical vein]

In order to improve the routine culture method for vascular endothelial cells, endothelial cells of vein from newborn umbilical cord were successfully isolated with combined using 0.1% collagenase and 0.25% trypsin (1:1). The endothelial cells were further abrated by mechanical method. The composition of culture medium was simplified by not adding vascular endothelial cell growth factor and heparin. The cultured cells were verified as vascular endothelial cells by morphology, ultramicromorphology and immunohistochemistry.

[Wear study of dental restoration materials with a new study-system in vitro]

OBJECTIVE

To investigate abrasive wear of composite resins in vitro.

METHODS

A chewing simulator was used to perform the abrasive wear of four composite resins in vitro and an accurate three-dimensional laser-scanning system was used to measure the abrasion los of the materials.

RESULTS

According to worn volumes, the order of five materials is: Enamel < Targis Dentin < Dentacolor < Artglass < Vita Zeta. According to the worn-depthest-points, the order of five materials is: Enamel < Targis Dentin < Artglass < Dentacolor < Vita Zeta.

CONCLUSION

Targis Dentin shows no significant difference on ware resistance from human enamel, while three other composite resins are poorer than human enamel. This system in vitro is effective, accurate, quick and economical.

[Study on uptake of fluoroquinolones by Staphylococcus aureus]

This study aimed to investigate the mechanism of Staphylococcus aureus' resistance to fluoroquinolones. The uptake of lomefloxacin, ofloxacin by Staphylococcus aureus and the effect of CCCP on the uptake were studied by the fluorescence method. The uptake of lomefloxacin, ofloxacin by sensitive organisms is higher than that by resistant organisms; CCCP had different influences on different organisms, but no significant difference between the effects of CCCP on sensitive strains and on resistant strains was noted. The uptake of lomefloxacin, ofloxacin by SA2-16 was much lower than that by SA2-16's parent, and after the addition of CCCP, the uptake of both quinolones by SA2-16 increased rapidly, but the concentration did not reach its parent's concentration in stable condition. These results indicate that the decreasing of the uptake of fluoroquinolones is one of the mechanisms responsible for Staphylococcus aureus to resistance fluoroquinolones, and as a mechanism of resistance to drugs, it plays different roles in different strains.

[Application of in vitro micronucleus tests using L5178Y mouse lymphoma and WTK1 human lymphoblastoid cell lines to antimutagenicity assay]

In the in vitro micronucleus (MN) tests using L5178Y mouse lymphoma and WTK1 human lymphoblastoid cell lines, 2 well-known antimutagens, Vitamin C (Vc) and the sodium and copper salt of chlorophyll (Chl), were tested to evaluate their ability to inhibit the mutagenicity of mitomycin C(MMC). Three kinds of treatment were designed, namely the simultaneous treatment with Vc (or Chl) and MMC, the use of Vc (or Chl) before the use of MMC, and the use of Vc (or Chl) after the use of MMC. The results showed that Vc and Chl had no MN inductivity in the two cell lines; that simultaneous treatment with Vc and MMC and pre-treatment with Vc effectively reduced MMC-induced MN cell frequencies; and that simultaneous treatment and pre-treatment with Chl at dose level of 0.12 mg/ml, significantly reduced MMC-induced MN cell frequencies of L5178Y cells. The antimutagenic effect of Chl on WTK1 cells was found in simultaneous and pre-treatment at dose levels of 0.12 and 0.06 mg/ml.

[Simultaneous determination of gibberellins A1 and A3 in foxtail millet seedlings by high performance liquid chromatography]

Gibberellin A1(GA1) and Gibberellin A3(GA3) in millet seedlings were simultaneously determined by HPLC on a Zorbax-ODS-C18 (4.6 mm x 250 mm, 10 microns) column, using a mobile phase consisting of V (0.02 mol/L phosphate buffer solution, pH 4.0):V(methanol) = 2.2:1, a flow rate of 0.8 mL/min and a UV detection at 210 nm. GA1 and GA3 were separated completely in 10 min. Correlation coefficients for linear equations were 0.9986 and 0.9978, recoveries were 102.54% and 99.59%, respectively. Two normal cultivars and their dwarf-mutants were determined by this method. The results showed that both GA1 and GA3 were discovered in foxtail millet seedling, and endogenous mass ratio of GA1 and GA3 in foxtail millet dwarf-mutants were significantly lower than those in normal cultivars, and the concentrations of endogenous GA1 and GA3 were important factors for plant-height.

[Molten organic salt--a new class of stationary phases for GC]

Molten organic salts are a new class of polar, selective stationary phases for gas chromatography. Their types and characters are reported in detail and compared with some common stationary phases.

Aberrant positioning of trophoblast and lymphocytes in the feto-maternal interface with pre-eclampsia

Pregnancy represents the growth of an allograft where fetal trophoblast cells evade immune rejection and invade maternal tissue. There should be a balance between fetal trophoblast and maternal immune-responsive cells and alterations in the proportion of these cells may relate to pregnancy disorders. To test this, the decidual tissue of placental bed biopsies was examined and trophoblast cells and lymphocytes were quantified morphometrically; spiral arteries were classified as unchanged, transformed or affected by acute atherosis. Normal pregnancy (n=19) was characterized by the transformation of about one half of all spiral arteries within the placental bed. We found that 40% of all lymphocytes were CD56+ uterine NK cells and 60%, CD3+ T-lymphocytes; about 30% of these were CD8+ T cells. Intrauterine growth retardation in the context of preeclampsia (n=15) was accompanied by reduced trophoblast numbers within smaller and more tortuous arteries and an increase in the proportion of CD56+ uterine NK cells and CD8+ T lymphocytes in the decidua (70% of all CD3+ cells). In the case of pre-eclampsia without fetal growth retardation (n=14) no increase in CD56+ uterine NK cells was seen, while CD8+ T lymphocytes were significantly increased compared with the normal level (50% of all CD3+ cells). Fetal growth retardation is associated with poor transformation of spiral arteries and characterized by an increase of uterine NK cells. Symptoms of pre-eclampsia are independently associated with an increase in the cytotoxic T subset of decidual lymphocytes. Pre-eclampsia and related fetal growth retardation are seemingly caused by an enhancement of the maternal cytotoxic defence against the fetal allograft.