Genotype I of hepatitis B virus was found in east Xishuangbanna, China and molecular dynamics of HBV/I

There is a dearth of data about the prevalence of hepatitis B virus (HBV) infection in Mengla, China; and no detailed analysis of the molecular evolution of genotype I in Asia. In this study, 909 serum samples from ethnic minority people in China were obtained. Serological assay and HBV S-gene amplification were carried out, and phylogenetic and evolutionary dynamics analysis of 62 HBV/I S-gene was performed. On this survey, 153 individuals were tested HBsAg-positive. Genotypes of S-gene were classified into three groups: C, B and I. Under the strict model and the relax model, the estimated evolutionary rates for HBV/I were 3.74 × 10(-4) and 6.93 × 10(-4) substitution/site/year, respectively. However, when the geographic origin was taken into account, the mean substitution rates were increased. Estimated time to most recent ancestor of genotype I varied from ~30 to ~70 years ago. The Bayesian sky plot showed a rapid spread of HBV/I at the end of 1980s. Peculiar nucleotides distributed were observed in the subgenotype I1/I2. In conclusion, higher prevalence of HBV infection was observed in Mengla county. Multifactors like timescale and spatial locations should be integrated to provide a better interpretation of the HBV/I evolutionary history in the region.

Percutaneous quadriceps tendon pie-crusting release of extension contracture of the knee

To release extension contracture of the knee, the authors used a minimally invasive technique: percutaneous quadriceps tendon pie-crusting release. Percutaneous pie-crusting release was performed using an 18-gauge needle to puncture the stiff fibrous band of the distal and lateral quadriceps tendon under maximum knee flexion. Quadriceps contracture was gradually released by multiple needle punctures. A knee brace was prescribed for one week and knee flexion exercises were performed on the first postoperative day. This technique was performed in seven post-traumatic stiff knees and five stiff total knee arthroplasties. Mean maximum flexion increased from 37° preoperatively to 50° after arthrolysis and 107(o) after pie-crusting. At a mean follow-up of eight months, mean maximum flexion was 103°. There were no major complications. The technique of quadriceps tendon pie-crusting release is a simple, minimally invasive and effective treatment for knee extension contracture.

Molecular genetic diversity and maternal origin of Chinese black-bone chicken breeds

Chinese black-bone chickens are valued for the medicinal properties of their meat in traditional Chinese medicine. We investigated the genetic diversity and systematic evolution of Chinese black-bone chicken breeds. We sequenced the DNA of 520 bp of the mitochondrial cyt b gene of nine Chinese black-bone chicken breeds, including Silky chicken, Jinhu black-bone chicken, Jiangshan black-bone chicken, Yugan black-bone chicken, Wumeng black-bone chicken, Muchuan black-bone chicken, Xingwen black-bone chicken, Dehua black-bone chicken, and Yanjin black-bone chicken. We found 13 haplotypes. Haplotype and nucleotide diversity of the nine black-bone chicken breeds ranged from 0 to 0.78571 and 0.00081 to 0.00399, respectively. Genetic diversity was the richest in Jinhu black-bone chickens and the lowest in Yanjin black-bone chickens. Analysis of phylogenetic trees for all birds constructed based on hyplotypes indicated that the maternal origin of black-bone chickens is predominantly from three subspecies of red jungle fowl. These results provide basic data useful for protection of black-bone chickens and help determine the origin of domestic chickens.

Formation of nanostructure and nano-hardness characterization on the meso-scale workpiece by a novel laser indirect shock forming method

The meso-scale workpiece with greatly enhanced mechanical properties is potential to be widely used in the electronics productions and micro-electro mechanical systems. In this study, it demonstrates that the meso-scale cup-shape workpiece with good geometry can be obtained by a novel laser indirect shock forming method. After the forming process, the mechanical properties and microstructures of the formed workpiece were characterized. By transmission electron microscope observation, it was found that a mixed refined microstructure consisting of nano-scale twins embedded in nano-sized grains was produced at the center of the formed sample. Formation of these nanograins could be mainly attributed to two mechanisms: twin-twin intersections and twin∕matrix lamellae fragmentation. By nanoindentation tests, it reveals that the hardness of the sample has increased greatly after laser shock forming and the hardness increases with the laser energy. The elevated hardness originates from a considerable number of nano-scale twins and nanograins, which possess a pretty high strength due to the significant effects of grain boundary strengthening and twin boundary strengthening.

QSAR of acute toxicity of halogenated phenol to green fluorescent protein by using density functional theory

A novel approach was established to predict toxicity of environmental pollutants by using green fluorescent protein (GFP) as bio-marker. In the approach, recombinant Escherichia coli was constructed to express GFP. The toxicity values (-lgEC (50)) of 14 halogenated phenols to recombinant E. coli with GFP gene were measured. And optimized calculation was carried out at B3LYP/6-31G* level using density functional theory method. Based on the MTLSER model, the obtained parameters were taken as theoretical descriptors to establish the novel QSAR model for predicting -lgEC (50) (R (2) = 0.922). The model includes two variables (standard entropy (S (θ)) and the most negative atomic net charges of the molecule (q (-))). The results of cross-validation test (q (2) = 0.868) indicate the model of this study has optimum stability, which shows that it is feasible to predict to toxicity of chemistry utilizing recombinant E. coli with GFP gene.

Stimulation of bone formation in the expanding premaxillary suture with a GSK-3β inhibitor

OBJECTIVES

Glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling mediates osteogenesis in response to mechanical loading. We tested the hypothesis that local administration of a GSK-3β inhibitor could stimulate new bone formation in the expanding premaxillary suture.

MATERIALS AND METHODS

Thirty-five Sprague-Dawley rats were subjected to premaxillary suture expansion using a helix spring. The experimental rats were given one or two local injections of SB-415286, a small-molecule GSK-3β inhibitor. Animals were administered calcein and sacrificed on day 7 to quantify new bone formation. To evaluate the proliferation and differentiation of osteoblasts, rats were labeled with bromodeoxyuridine on day 1 and sacrificed on day 2 or 4. β-catenin expression was evaluated by immunohistochemical staining.

RESULTS

Two injections of SB-415286 led to an elevation of β-catenin expression and an increase in the number of proliferating osteoblasts in expanding sutures on day 2 and day 4. Consequently, new bone formation in the suture increased significantly on day 7.

CONCLUSIONS

These results suggest that local delivery of a GSK-3β inhibitor could stimulate bone formation in the expanding premaxillary suture by eliciting β-catenin signaling. GSK-3β could be a pharmaceutical target for improving the effect of orthodontic treatments such as rapid palatal expansion.

The complete mitochondrial genome of the rodent intra-arterial nematodes Angiostrongylus cantonensis and Angiostrongylus costaricensis

The two rodent intra-arterial nematodes, Angiostrongylus cantonensis and Angiostrongylus costaricensis, can cause human ill-health. The present study aimed to characterize and compare the mitochondrial (mt) genomes of these two species, and clarify their phylogenetic relationship and the position in the phylum Nematoda. The complete mt genomes of A. cantonensis and A. costaricensis are 13,497 and 13,585 bp in length, respectively. Hence, they are the smallest in the class of Chromadorea characterized thus far. Like many nematode species in the class of Chromadorea, they encode 12 proteins, 22 transfer RNAs, and two ribosomal RNAs. All genes are located on the same strand. Nucleotide identity of the two mt genomes is 81.6%, ranging from 77.7% to 87.1% in individual gene pairs. Our mt genome-wide analysis identified three major gene arrangement patterns (II-1, II-2, and II-3) from 48 nematode mt genomes. Both patterns II-1 and II-2 are distinct from pattern II-3, which covers the Spirurida, supporting a closer relationship between Ascaridida and Strongylida rather than Spirurida. Thymine (T) was highly concentrated on coding strands in Chromadorea, but balanced between the two strands in Enoplea, probably due to the gene arrangement pattern. Interestingly, the gene arrangement pattern of mt genomes and phylogenetic analysis based on concatenated amino acids indicated a closer relationship between the order Ascaridida and Rhabditida rather than Spirurida as indicated in previous studies. These discrepancies call for new research, reassessing the position of the order of Ascaridida in the phylogenetic tree. Once consolidated, the findings are important for population genetic studies and target identification.

Nanosecond field-induced quenching of the luminescence from Er-doped silicon nanocrystals

Er-doped Si-rich SiO2 gate oxide layers containing silicon nanocrystals are prepared by implantation of Si+ and Er+ into SiO2 thin films. The photoluminescence from both Si nanocrystals around 700-850 nm and Er3+ ions at 1.54 microm is strongly quenched by applying electric field in the Si-rich oxide layer. The quenching time and the recovery time of the photoluminescence from Si nanocrystals are less than 50 ns under pulsed field modulation. The quenching rate of the luminescence increases with increasing the density and reducing the size of the silicon nanocrystals. Our results indicate that the fast quenching process originates from the quantum confined Stark effect and enhanced exciton ionization by carrier tunneling between the silicon nanocrystals under the high electric field.

First Report of Pantoea agglomerans Causing Brown Apical Necrosis of Walnut in China

Brown apical necrosis (BAN) of walnut (Juglans regia L.) causes premature fruit drop and yield losses and has been reported to be an important walnut production problem in Spain, Italy, France, and Turkey (1,2). A number of organisms have been associated with BAN on walnut: Xanthomonas arboricola pv. juglandis, Fusarium spp., and Alternaria spp. (3). Since the spring of 2007, BAN was observed in 50 to 60% of the trees in walnut orchards in Taian City and Laiwu City, Shandong Province, China. Surface-disinfested tissue from premature walnut fruits was placed onto potato dextrose agar. Alternaria spp., X. arboricola pv. juglandis, and Pantoea agglomerans (formerly Enterobacter agglomerans) were isolated 76, 35, and 45% of the time, respectively. The P. agglomerans cultures formed a yellow lawn and were rod shaped with the body length of 1.5 to 3.0 μm, width of 0.5 to 1.0 μm, and four to six flagella. In biochemical tests, these bacteria were gram negative, lactose positive, and indole negative. Genomic DNA was extracted from one HXJ isolate and the 16S rRNA gene sequence (GenBank Accession No. HM016799) was obtained using universal primers 27F and 1492R. HM016799 had 99% sequence identity with P. agglomerans accessions in GenBank (GU477762, GQ494018, FJ756355, and AB004757). To confirm pathogenicity, HXJ isolate (10⁸ CFU·ml^-1) was inoculated at the bottom of the stigma within 5 days after florescence (DAF) and in premature fruit wounded with a needle within 30 DAF in 2008 to 2010. Stigmas injected with only sterile water served as controls. The bacteria were inoculated into three replicate 9-year-old plants of the walnut cv. Xiangling. Forty nuts on each plant were inoculated. The plants were grown in Shandong Province, China (36°09'59″N, 117°13'30″E). Ten days after inoculation, typical internal BAN symptoms were observed on all treated nuts and the controls were still healthy. In the inoculated stigmas, necrosis of stigma and style spread to internal tissues and reached the kernel. In treated premature fruit, internal tissues became necrotic and blackish and eventually led to nut drop. The same bacterium was reisolated from the inoculated tissue. On the basis of morphological, physiological, and biochemical characteristics and sequencing of the 16S rRNA gene, the bacterium was identified as P. agglomerans. To our knowledge, this is the first report of P. agglomerans causing internal type BAN of walnut in China or worldwide. References: (1) A. Belisario et al. Plant Dis. 6:599, 2002. (2) G. Bouvet. Acta Hortic. 705:447, 2005. (3) C. Moragrega and H. Özaktan. J. Plant Pathol. 92:S1.67, 2010.

[Population genetics of Pomacea spp. in mainland of China]

OBJECTIVE

To reveal the population structure of Pomacea spp. using genetic markers so as to provide the evidence for studying the invasion and expansion of it in the mainland of China.

METHODS

The genetics of 581 specimens of Pomacea spp. from 60 sites was analyzed by sequencing CO I gene. The diversity of nucleotide and haplotypes were calculated in DnaSP 5.10.01. The haplotype network analysis was performed in Network 4.2.0.1. A phylogenetic tree was produced based on the haplotypes from the present study and those available from GenBank in order to understand the taxonomic status of Pomacea spp. in China.

RESULTS

A total of 556 sequences were acquired in the present study and produced 25 unique haplotypes. Six haplotypes frequently occurred in the specimens and accounted for 96.0%. The phylogenetic analysis identified two Pomacea species in China, i. e. P. canaliculata and P. insularum. The usage of haplotypes of P. insularum in China reversed from the existing pattern in other countries.

CONCLUSION

The complexity of population structure of Pomacea spp. in the mainland of China indicates multi-original introduction and complicated expansion patterns.

[Multiplex PCR assay for the detection of Angiostrongylus cantonensis larvae in Pomacea canaliculata]

OBJECTIVE

To establish a multiplex PCR assay for detecting Angiostrongylus cantonensis larvae in Pomacea canaliculata.

METHODS

A pair of specific primers was designed based on the sequences of the small subunit rDNA of A. cantonensis (GenBank jAY295804), in combination with 16s rDNA specific primers of P. canaliculata, a multiplex PCR was developed. The PCR was performed on positive and negative snails, and the amplified products were analyzed by agarose gel electrophoresis and DNA sequencing. DNA template of 200 III stage larvae of A. cantonensis was diluted by negative snail DNA (1200 ng/microl, 120 ng/microl, 12 ng/microl, 1200 pg/microl, 120 pg/microl and 12 pg/microl), to find the minimum detectable level. Single blind method was used to evaluate the accuracy. After being detected by lung microscopy, 172 snails from field were tested by the multiplex PCR to assess the sensitivity and specificity.

RESULTS

Agarose gel electrophoresis and DNA sequencing analysis indicated that the target sequences were efficiently amplified by the PCR assay (550 bp for P. canaliculata, 405 bp for A. cantonensis). The minimum detectable level was 120 pg/microl. The coincidence between the two methods stood for 84.3% (145/172), including 45 positives and 100 negatives. 24 snails were PCR positive and microscopy negative, 3 snails were PCR negative and microscopy positive. The sensitivity and specificity of multiplex PCR was 93.8% and 80.6%, respectively. Its positive rate (40.1%, 69/172) was significant higher than that of lung-microscopy (27.9%, 48/172)(chi2 = 14.8, P < 0.01).

CONCLUSION

A multiplex PCR method has been developed for the detection of A. cantonensis larvae in P. canaliculata.

[The first national survey on natural nidi of Angiostrongylus cantonensis in China]

OBJECTIVE

To reveal the natural distribution of Angiostrongylus cantonensis in the mainland of China.

METHODS

The potential areas of A. cantonensis and its main intermediate host Pomacea canaliculata were predicted based on degree-day models using GIS technique. A grid sampling was performed on the prediction map and 5% grids were randomly sampled. A total of 55 sampled sites were selected for the survey on A. cantonensis and its hosts in September-October of 2006.

RESULTS

Nineteen Provinces/Municipalities/Autonomous Regions were found as potential habitats for P. canaliculata in the mainland of China. It was then confirmed that the snails distributed in the provinces of Fujian, Jiangxi, Zhejiang, Hunan, Guangdong, Guangxi, Hainan, and Yunnan. Higher prevalence of A. cantonensis in P. canaliculata was detected in Jianou of Fujian (36.6%), Xingguo of Jiangxi (19.9%), Rui'an of Zhejiang (16.0%), Rucheng of Hunan (5.0%), Huazhou of Guangdong (6.3%), Shangsi of Guangxi (39.1%) and Wuzhishan of Hainan (25.0%).

CONCLUSION

Natural nidi of A. cantonensis have been found in seven provinces where natural infection in P. canaliculata has been detected.

Invasive snails and an emerging infectious disease: results from the first national survey on Angiostrongylus cantonensis in China

BACKGROUND

Eosinophilic meningitis (angiostrongyliasis) caused by Angiostrongylus cantonensis is emerging in mainland China. However, the distribution of A. cantonensis and its intermediate host snails, and the role of two invasive snail species in the emergence of angiostrongyliasis, are not well understood.

METHODOLOGY/PRINCIPAL FINDINGS

A national survey pertaining to A. cantonensis was carried out using a grid sampling approach (spatial resolution: 40x40 km). One village per grid cell was randomly selected from a 5% random sample of grid cells located in areas where the presence of the intermediate host snail Pomacea canaliculata had been predicted based on a degree-day model. Potential intermediate hosts of A. cantonensis were collected in the field, restaurants, markets and snail farms, and examined for infection. The infection prevalence among intermediate host snails was estimated, and the prevalence of A. cantonensis within P. canaliculata was displayed on a map, and predicted for non-sampled locations. It was confirmed that P. canaliculata and Achatina fulica were the predominant intermediate hosts of A. cantonensis in China, and these snails were found to be well established in 11 and six provinces, respectively. Infected snails of either species were found in seven provinces, closely matching the endemic area of A. cantonensis. Infected snails were also found in markets and restaurants. Two clusters of A. cantonensis-infected P. canaliculata were predicted in Fujian and Guangxi provinces.

CONCLUSIONS/SIGNIFICANCE

The first national survey in China revealed a wide distribution of A. cantonensis and two invasive snail species, indicating that a considerable number of people are at risk of angiostrongyliasis. Health education, rigorous food inspection and surveillance are all needed to prevent recurrent angiostrongyliasis outbreaks.

Angiostrongylus cantonensis: morphological and behavioral investigation within the freshwater snail Pomacea canaliculata

An infection with Angiostrongylus cantonensis, the main causative agent for human eosinophilic encephalitis, can be acquired through the consumption of the freshwater snail Pomacea canaliculata. This snail also provides a suitable model to study the developmental morphology and behavior of A. cantonensis larvae, facilitated by the snail's distinct lung structure. We used microanatomy for studying the natural appearance and behavior of A. cantonensis larvae while developing within P. canaliculata. The distribution of refractile granules in the larval body and characteristic head structures changed during the developmental cycle. Two well-developed, rod-like structures with expanded knob-like tips at the anterior part were observed under the buccal cavity as early as the late second developmental stage. A "T"-shaped structure at the anterior end and its tenacity distinguished the outer sheath from that shed during the second molting. Early first-stage larvae obtained from fresh rat feces are free moving and characterized by a coiled tail, whereas a mellifluous "Q"-movement was the behavioral trait of third-stage A. cantonensis larvae outside the host tissue. In combination, the distribution of refractive granules, distinct head features, variations in sheaths, and behavioral characteristics can be utilized for differentiation of larval stages, and for distinguishing A. cantonensis larvae from those of other free-living nematodes.

[Morphology of III stage larvae of Angiostrongylus cantonensis in Pomacea canaliculata]

OBJECTIVE

To observe the morphologic characteristics of III stage larvae of Angiostrongylus cantonensis from Pomacea canaliculata.

METHODS

P. canaliculata, the intermediate host snail of A. cantonensis, was infected with I stage larvae of A. cantonensis in laboratory. After 61 days, III stage larvae of A. cantonensis were harvested from snail's lungs and muscle of head-foot, followed by HE stain to observe morphological characteristics.

RESULTS

The whole body of III stage larva was curling with obtuse head. Its pharyngeal canal extends from the buccal hole on the top of the head to the intestines at the pharyngeal intestine joint place, with apex cauda and clear anal tube. The tegument of the III stage larva was eosin-stained, with a transparent sheath outside of tegument. Some of the larvae cauda showed in circular cylinder, and some larvae presented ventral gland with two very short uterine which used to be the feature only showed in early IV stage larva.

CONCLUSION

Morphologically characteristics of the III stage larvae is helpful to better understand the life-cycle and the control of A. cantonensis.

Determination of solubilities and n-octanol/water partition coefficients and QSPR study for substituted phenols

A shake-flask method was employed to determine the water solubility (-lgS (w)) and n-octanol/water partition coefficient (lgK (ow)) of 20 substituted phenols at 298.15 K. And optimized calculation was carried out at B3LYP/6-311G** level with DFT method. Afterwards the obtained parameters were taken as theoretical descriptors to establish the QSPR models for predicting -lgS (w) and lgK (ow), in which the conventional correlation coefficients (R (2)) are 0.9800 and 0.9941, respectively. The two models were further validated by variance inflation factors (VIF) and t-test. Upon comparison, the stability and predictive power are more advantageous than those based on AM1 molecular orbital method and molecular connectivity method.

Detection of human parvovirus B19 in papillary thyroid carcinoma

To evaluate whether parvovirus B19, a common human pathogen, was also involved in papillary thyroid carcinoma (PTC), 112 paraffin-embedded thyroid specimens of benign nodules, papillary, medullary and follicular carcinomas, and normal controls were examined for B19 DNA and capsid protein by nested PCR, in situ hybridisation (ISH) and immunohistochemistry (IHC). The expression of the nuclear factor-κB (NF-κB) was investigated by IHC. The results showed B19 DNA commonly exists in human thyroid tissues; however, there were significant differences between PTC group and normal controls, and between PTC and nonneoplastic adjacent tissues (P<0.001). The presence of viral DNA in PTC neoplastic epithelium was confirmed by laser-capture microdissection and sequencing of nested PCR products. B19 capsid protein in PTC group was significantly higher than that of all the control groups and nonneoplastic adjacent tissues (P⩽0.001). Compared with control groups, the activation of NF-κB in PTC group was significantly increased (P⩽0.02), except for medullary carcinomas, and the activation of NF-κB was correlated with the viral protein presence (P=0.002). Moreover, NF-κB was colocalised with B19 DNA in the neoplastic epithelium of PTC by double staining of IHC and ISH. These results indicate for the first time a possible role of B19 in pathogenesis of PTC.

[A comparative study of three methods in detecting Angiostrongylus cantonensis larvae in lung tissue of Pomacea canaliculata]

OBJECTIVE

To compare the efficiency of three methods, lung-microscopy, tissue homogenate and enzyme digestion in the detection of Angiostrongylus cantonensis larvae from the lungs of snails.

METHODS

60 Pomacea canalicular infected by the first-stage larvae of A. cantonensis were divided into 2 groups and the lung of each snail from the two groups was separated from the soft body. All the lungs were examined under microscope and larval nodes were counted. Each lung from one group was ground and that from the other was artificially digested by enzyme, the number of larvae in each lung was recorded. The efficiency of three methods was compared. Enzyme digestion was also used to estimate number of larvae in lung and in other body parts.

RESULTS

By using enzyme digestion as the standard method, the detection rate of lung-microscopy, tissue homogenate and enzyme digestion was 96.7%, 93.4% and 100% respectively (chi2=2.069, P>0.05), while the lung-microscopy was significantly faster (Z=4.782, P<0.01). The number of larvae in snail lung was positively correlated with that in other part (r=0.847, P<0.01).

CONCLUSIONS

The lung-microscopy in larvae detection is similarly efficient to the other two methods but faster, which is therefore more suitable for snail screening in the field.

The effect of temperature on the development of Angiostrongylus cantonensis (Chen 1935) in Pomacea canaliculata (Lamarck 1822)

Angiostrongyliasis cantonensis, clinically presented as eosinophilic meningitis, is a snail-borne parasitic disease. We studied the effects of different temperatures on the larval development of Angiostrongylus cantonensis in the freshwater snail Pomacea canaliculata. Six groups of snails were infected and each group was cultured under different temperature conditions. At predefined intervals, four snails from each group were dissected to examine the larval development. The development-time curve of each group was drawn according to the fraction of third-stage larvae present. The developmental time was defined as the time needed until 50% of the first-stage larvae developed into third-stage larvae. A linear regression model was established based on the time (D; in days) and the corresponding temperature (T; in degrees Celsius): DT = 15.04 x D + 262.53. The threshold temperature for larval development was 15.04 degrees C and the thermal constant was 262.53 degree-days. These parameters could be helpful in estimating the number of parasite generations in a year and the impact of climate change on the distribution of A. cantonensis.

Inhibitory effects of four carbamate insecticides on acetylcholinesterase of male and female Carassius auratus in vitro

The inhibitory effects of four carbamate insecticides, methomyl, thiodicarb, carbofuran and carbosulfan, on acetylcholinesterase of male and female Carassius auratus were investigated in the laboratory. Kinetic constants, biomolecular rate constant (k(i)), carbamylation rate constant (k2) and decarbamylation rate constant (k3) were determined in vitro. The ratios of bimolecular rate constant (female/male) for AChE reacting with methomyl, thiodicarb, carbofuran and carbosulfan were 1.03, 2.44, 1.03 and 1.106, respectively. The k(i) of AChE for thiodicarb was significantly higher in female fish than in male fish (P<0.05). The ratios of carbamylation rate constant (female/male) for methomyl, thiodicarb, carbofuran and carbosulfan were 1.18, 4.29, 3.53, and 2.07, respectively. The k2 values of AChE for the above four carbamates were significantly higher in females than in males. The ratios of the decarbamylation rate constant (female/male) for methomyl, thiodicarb, carbofuran and carbosulfan were 1.02, 1.39, 1.06, and 1.98, respectively. Only for carbosulfan, the decarbamylation rate of AChE was significantly higher in the female than in the male, indicating that AChE of females inhibited by carbosulfan recovered more quickly than that of males. The above results suggest that the female in the sensitivity of AChE to carbamates was different from the male fish.

Support vector machines-based quantitative structure-property relationship for the prediction of heat capacity

The support vector machine (SVM), as a novel type of learning machine, for the first time, was used to develop a Quantitative Structure-Property Relationship (QSPR) model of the heat capacity of a diverse set of 182 compounds based on the molecular descriptors calculated from the structure alone. Multiple linear regression (MLR) and radial basis function networks (RBFNNs) were also utilized to construct quantitative linear and nonlinear models to compare with the results obtained by SVM. The root-mean-square (rms) errors in heat capacity predictions for the whole data set given by MLR, RBFNNs, and SVM were 4.648, 4.337, and 2.931 heat capacity units, respectively. The prediction results are in good agreement with the experimental value of heat capacity; also, the results reveal the superiority of the SVM over MLR and RBFNNs models.

Prediction of the tissue/blood partition coefficients of organic compounds based on the molecular structure using least-squares support vector machines

The accurate nonlinear model for predicting the tissue/blood partition coefficients (PC) of organic compounds in different tissues was firstly developed based on least-squares support vector machines (LS-SVM), as a novel machine learning technique, by using the compounds' molecular descriptors calculated from the structure alone and the composition features of tissues. The heuristic method (HM) was used to select the appropriate molecular descriptors and build the linear model. The prediction result of the LS-SVM model is much better than that obtained by HM method and the prediction values of tissue/blood partition coefficients based on the LS-SVM model are in good agreement with the experimental values, which proved that nonlinear model can simulate the relationship between the structural descriptors, the tissue composition and the tissue/blood partition coefficients more accurately as well as LS-SVM was a powerful and promising tool in the prediction of the tissue/blood partition behaviour of compounds. Furthermore, this paper provided a new and effective method for predicting the tissue/blood partition behaviour of the compounds in the different tissues from their structures and gave some insight into structural features related to the partition process of the organic compounds in different tissues.

Diagnosing anorexia based on partial least squares, back propagation neural network, and support vector machines

Support vector machine (SVM), as a novel type of learning machine, for the first time, was used to develop a predictive model for early diagnosis of anorexia. It was based on the concentration of six elements (Zn, Fe, Mg, Cu, Ca, and Mn) and the age extracted from 90 cases. Compared with the results obtained from two other classifiers, partial least squares (PLS) and back-propagation neural network (BPNN), the SVM method exhibited the best whole performance. The accuracies for the test set by PLS, BPNN, and SVM methods were 52%, 65%, and 87%, respectively. Moreover, the models we proposed could also provide some insight into what factors were related to anorexia.

QSAR study of natural, synthetic and environmental endocrine disrupting compounds for binding to the androgen receptor

A large data set of 146 natural, synthetic and environmental chemicals belonging to a broad range of structural classes have been tested for their relative binding affinity (expressed as log (RBA)) to the androgen receptor (AR). These chemicals commonly termed endocrine disrupting compounds (EDCs) present a variety of adverse effects in humans and animals. As assays for binding affinity remains a time-consuming task, it is important to develop predictive methods. In this work, quantitative structure-activity relationships (QSARs) were determined using three methods, multiple linear regression (MLR), radical basis function neural network (RBFNN) and support vector machine (SVM). Five descriptors, accounting for hydrogen-bonding interaction, distribution of atomic charges and molecular branching degree, were selected from a heuristic method to build predictive QSAR models. Comparison of the results obtained from three models showed that the SVM method exhibited the best overall performances, with a RMS error of 0.54 log (RBA) units for the training set, 0.59 for the test set, and 0.55 for the whole set. Moreover, six linear QSAR models were constructed for some specific families based on their chemical structures. These predictive toxicology models, should be useful to rapidly identify potential androgenic endocrine disrupting compounds.

QSAR and classification models of a novel series of COX-2 selective inhibitors: 1,5-diarylimidazoles based on support vector machines

The support vector machine, which is a novel algorithm from the machine learning community, was used to develop quantitation and classification models which can be used as a potential screening mechanism for a novel series of COX-2 selective inhibitors. Each compound was represented by calculated structural descriptors that encode constitutional, topological, geometrical, electrostatic, and quantum-chemical features. The heuristic method was then used to search the descriptor space and select the descriptors responsible for activity. Quantitative modelling results in a nonlinear, seven-descriptor model based on SVMs with root mean-square errors of 0.107 and 0.136 for training and prediction sets, respectively. The best classification results are found using SVMs: the accuracy for training and test sets is 91.2% and 88.2%, respectively. This paper proposes a new and effective method for drug design and screening.

The prediction of human oral absorption for diffusion rate-limited drugs based on heuristic method and support vector machine

Support vector machine (SVM), as a novel machine learning technique, was used for the prediction of the human oral absorption for a large and diverse data set using the five descriptors calculated from the molecular structure alone. The molecular descriptors were selected by heuristic method (HM) implemented in CODESSA. At the same time, in order to show the influence of different molecular descriptors on absorption and to well understand the absorption mechanism, HM was used to build several multivariable linear models using different numbers of molecular descriptors. Both the linear and non-linear model can give satisfactory prediction results: the square of correlation coefficient R(2) was 0.78 and 0.86 for the training set, and 0.70 and 0.73 for the test set respectively. In addition, this paper provides a new and effective method for predicting the absorption of the drugs from their structures and gives some insight into structural features related to the absorption of the drugs.

Quantitative Prediction of logk of Peptides in High-Performance Liquid Chromatography Based on Molecular Descriptors by Using the Heuristic Method and Support Vector Machine

A new method support vector machine (SVM) and the heuristic method (HM) were used to develop the nonlinear and linear models between the capacity factor (logk) and seven molecular descriptors of 75 peptides for the first time. The molecular descriptors representing the structural features of the compounds only included the constitutional and topological descriptors, which can be obtained easily without optimizing the structure of the molecule. The seven molecular descriptors selected by the heuristic method in CODESSA were used as inputs for SVM. The results obtained by SVM were compared with those obtained by the heuristic method. The prediction result of the SVM model is better than that of heuristic method. For the test set, a predictive correlation coefficient R = 0.9801 and root-mean-square error of 0.1523 were obtained. The prediction results are in very good agreement with the experimental values. But the linear model of the heuristic method is easier to understand and ready to use for a chemist. This paper provided a new and effective method for predicting the chromatography retention of peptides and some insight into the structural features which are related to the capacity factor of peptides.

QSAR Models for the Prediction of Binding Affinities to Human Serum Albumin Using the Heuristic Method and a Support Vector Machine

The binding affinities to human serum albumin for 94 diverse drugs and drug-like compounds were modeled with the descriptors calculated from the molecular structure alone using a quantitative structure-activity relationship (QSAR) technique. The heuristic method (HM) and support vector machine (SVM) were utilized to construct the linear and nonlinear prediction models, leading to a good correlation coefficient (R2) of 0.86 and 0.94 and root-mean-square errors (rms) of 0.212 and 0.134 albumin drug binding affinity units, respectively. Furthermore, the models were evaluated by a 10 compound external test set, yielding R2 of 0.71 and 0.89 and rms error of 0.430 and 0.222. The specific information described by the heuristic linear model could give some insights into the factors that are likely to govern the binding affinity of the compounds and be used as an aid to the drug design process; however, the prediction results of the nonlinear SVM model seem to be better than that of the HM.

An Accurate QSPR Study of O−H Bond Dissociation Energy in Substituted Phenols Based on Support Vector Machines

The support vector machine (SVM), as a novel type of learning machine, was used to develop a Quantitative Structure-Property Relationship (QSPR) model of the O-H bond dissociation energy (BDE) of 78 substituted phenols. The six descriptors calculated solely from the molecular structures of compounds selected by forward stepwise regression were used as inputs for the SVM model. The root-mean-square (rms) errors in BDE predictions for the training, test, and overall data sets were 3.808, 3.320, and 3.713 BDE units (kJ mol(-1)), respectively. The results obtained by Gaussian-kernel SVM were much better than those obtained by multiple linear regression, radial basis function neural networks, linear-kernel SVM, and other QSPR approaches.

Prediction of the Isoelectric Point of an Amino Acid Based on GA-PLS and SVMs

The support vector machine (SVM), as a novel type of a learning machine, for the first time, was used to develop a QSPR model that relates the structures of 35 amino acids to their isoelectric point. Molecular descriptors calculated from the structure alone were used to represent molecular structures. The seven descriptors selected using GA-PLS, which is a sophisticated hybrid approach that combines GA as a powerful optimization method with PLS as a robust statistical method for variable selection, were used as inputs of RBFNNs and SVM to predict the isoelectric point of an amino acid. The optimal QSPR model developed was based on support vector machines, which showed the following results: the root-mean-square error of 0.2383 and the prediction correlation coefficient R=0.9702 were obtained for the whole data set. Satisfactory results indicated that the GA-PLS approach is a very effective method for variable selection, and the support vector machine is a very promising tool for the nonlinear approximation.

[Effect of artemether on enzymes involved in carbohydrate metabolism of Schistosoma japonicum]

OBJECTIVE

To study the effect of artemether on several enzymes involved in carbohydrate metabolism of Schistosoma japonicum.

METHODS

Mice infected with Schistosoma japonicum cercariae for 4-5 weeks were administered intragastrically with artemether 300 mg/kg and killed 24-72 h after medication. The supernatant fluids of female and male worm homogenates were prepared for determining 9 essential enzymes of carbohydrate metabolism by using horizontal starchgel electrophoresis.

RESULTS

The activities of 8 out of 9 enzymes (i.e. hexokinase, aldolase, glucosephophate isomerase, malate dehydrogenase, malic enzyme, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and mannose-6-phosphate isomerase) in female worms from artemether-treated mice were obviously inhibited 24-72 h after treatment. In male worms, only aldolase, mannose-6-phosphate isomerase and glucose 6-phosphate dehydrogenase were slightly inhibited.

CONCLUSION

Artemether displayed apparent effects on the carbohydrate metabolism of female schistosomes.

[Allozyme-based genetic variation within an unstable "population" of Chinese Oncomelania hupensis (Gastropoda: Rissoacea: Pomatiopsidae)]

OBJECTIVE

To answer the following questions: 1. For Oncomelania snails collected two years apart from the same locality, has there been genetic divergence? 2. How much experimental error has there been in studying subsets of these populations? 3. As this is an unstable population, what has the net effect been on Hardy-Weinberg equilibrium (HWe)?

METHODS

Allozymes were studied using horizontal starch gel electrophoresis. Data collected from numbers of experiments were compiled. Data from each collection were divided into two equal subsets based on chronology of the experiments. Thirty-four loci were studied using 72 to 180 snails per subset.

RESULTS

The mean number of alleles per locus ranged from 1.5-1.9. With each consecutive subset, the % polymorphic loci dropped from 38.2 to 17.6. The mean heterozygosity was very low: 0.033 to 0.049 and not significantly different from Hardy-Weinberg expectations. Ten loci and 11 alleles exclusive to the first group were eliminated from the overall study reducing the number of polymorphic loci from 19 to 10. There were significant departures from HWe at five loci having a substantial number of individuals for each allele. Nei's and Wright's D were 0.003 +/- 0.001 and 0.054 +/- 0.006 respectively.

CONCLUSION

1. There were significant errors seen primarily in the results scored in the earliest experiments. 2. These earlier errors involving scoring difficult to resolve loci, and interpretation of rare alleles that were not found in later experiment had no significant effect on overall genetic distance. 3. The use of Wright's D for closely related populations is explained. Results with Nei's D indicated no significant difference among the four subunits; Wright's D yielded significant difference between the collections made two years apart, attributed to the annual flooding of the Yangtze River mixing snails from different localities. 4. Major polymorphic loci were not in Hwe as predicted using the unstable population model. 5. One must study 25 or more individuals to find relatively rare alleles and study population genetics.

QSAR study of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl) pyrimidine-5-carboxylate: an inhibitor of AP-1 and NF-kappa B mediated gene expression based on support vector machines

The support vector machine, as a novel type of learning machine, for the first time, was used to develop a QSAR model of 57 analogues of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl)pyrimidine-5-carboxylate (EPC), an inhibitor of AP-1 and NF-kappa B mediated gene expression, based on calculated quantum chemical parameters. The quantum chemical parameters involved in the model are Kier and Hall index (order3) (KHI3), Information content (order 0) (IC0), YZ Shadow (YZS) and Max partial charge for an N atom (MaxPCN), Min partial charge for an N atom (MinPCN). The mean relative error of the training set, the validation set, and the testing set is 1.35%, 1.52%, and 2.23%, respectively, and the maximum relative error is less than 5.00%.

Diagnosing breast cancer based on support vector machines

The Support Vector Machine (SVM) classification algorithm, recently developed from the machine learning community, was used to diagnose breast cancer. At the same time, the SVM was compared to several machine learning techniques currently used in this field. The classification task involves predicting the state of diseases, using data obtained from the UCI machine learning repository. SVM outperformed k-means cluster and two artificial neural networks on the whole. It can be concluded that nine samples could be mislabeled from the comparison of several machine learning techniques.

Improvements to B cell clonality analysis using PCR amplification of immunoglobulin light chain genes

AIMS

Clonality analysis using polymerase chain reaction (PCR) amplification of the immunoglobulin heavy chain (IgH) gene is an important aid to the diagnosis of B cell lymphoproliferative diseases. However, the method has a relatively high false negative rate. In an attempt to improve detection rates simple PCR strategies for clonality analysis of B cell populations using amplification of Ig light chain genes have been developed.

METHODS

Novel PCR protocols, designed to amplify Ig kappa and Ig lambda light chain genes, were evaluated using high molecular weight DNA samples from 28 selected cases of B cell lymphoma with known light chain expression and 12 reactive lymphoid specimens. Products were run on 10% polyacrylamide minigels using heteroduplex analysis. Conventional IgH PCR analysis was also performed. Twelve randomly selected formalin fixed, paraffin wax processed samples from cases submitted for molecular genetic analysis were also studied.

RESULTS

Polyclonal products were seen in all reactive lymphoid samples. Using Ig kappa PCR, 24 of 28 lymphomas, including four of five IgH negative cases, displayed monoclonal patterns. Using Ig lambda PCR, eight of 12 Ig lambda expressing tumours, including two of five IgH negative cases, showed monoclonal patterns. Standard IgH PCR demonstrated monoclonality in 23 of 28 B cell lymphomas. The detection rate was improved to 27 of 28 lymphomas using heavy and light chain PCR. Efficient amplification was achieved using paraffin wax processed samples, seven of which showed monoclonality compared with eight using IgH PCR.

CONCLUSIONS

Ig light chain PCR, used in conjunction with heavy chain analysis, enables improved detection of B cell monoclonality using routine histological specimens and can provide additional clone specific markers for the study of the biology of B cell tumours.

[Comparison between therapeutic effects of transcutaneous electrical nerve stimulation with the frequency of 2 Hz and 100 Hz on Chronic inflammatory pain in rats]

OBJECTIVE

To observe the effects of repeated transcutaneous nerve stimulation (TENS) with low frequency (2 Hz) and high frequency (100 Hz) on the chronic inflammatory pain.

METHODS

The complete Freund's adjuvant was used to make the monoadjuvant arthritis as a chronic inflammatory pain model. The model animals were divided into 3 groups, the 100 Hz TENS group, the 2 Hz TENS group and the control group. The percentage increase of body weight, circumference of ankle, score of flexion pain test and score of extension pain test were used to evaluate the therapeutic effect of TENS.

RESULTS

(1) Body weight increasing rate in the 100 Hz TENS group was markedly higher than that in the 2 Hz TENS group and the control group. (2) Circumference of rats' ankle in the 100 Hz TENS group was smaller than that in the 2 Hz TENS and the control group. (3) Repeated 100 Hz TENS showed more effective on pain relief than that of 2 Hz TENS.

CONCLUSION

TENS has therapeutic effects on chronic inflammatory pain in rats, and different frequencies yielded different results.

[The molecular mechanism of high glucose-induced insulin resistance in 3T3-L1 adipocytes]

We investigated the cellular effect of high glucose using 3T3-L1 adipocytes on glucose transport activity, the expression of insulin signaling proteins and IRS1 tyrosine phosphorylation. Results showed that adipocytes treated with different high glucose (10, 15 and 25 mmol.L-1) for 24 hours showed to impair the basal and insulin-induced increase in glucose uptake in a dose-dependent manner and decreased significantly IRS1 tyrosine phosphorylation. High concentration of glucose produced opposite effects on IRS1 and IRS2: down-regulated IRS1 protein expression level and tightly up-regulated IRS2 contents. p85 and PKB were unaffected. Chronic exposure to high glucose can inhibit glucose uptake and induce insulin resistance. The mechanism may be involved in affecting the expression of insulin signaling peptides and tyrosine phosphorylation.

Receptor subtype-specific pronociceptive and analgesic actions of galanin in the spinal cord: selective actions via GalR1 and GalR2 receptors

Galanin is a 29-aa neuropeptide with a complex role in pain processing. Several galanin receptor subtypes are present in dorsal root ganglia and spinal cord with a differential distribution. Here, we describe a generation of a specific galanin R2 (GalR2) agonist, AR-M1896, and its application in studies of a rat neuropathic pain model (Bennett). The results show that in normal rats mechanical and cold allodynia of the hindpaw are induced after intrathecal infusion of low-dose galanin (25 ng per 0.5 microl/h). The same effect is seen with equimolar doses of AR-M1896 or AR-M961, an agonist both at GalR1 and GalR2 receptors. In allodynic Bennett model rats, the mechanical threshold increased dose-dependently after intrathecal injection of a high dose of AR-M961, whereas no effect was observed in the control or AR-M1896 group. No effect of either of the two compounds was observed in nonallodynic Bennett model rats. These data indicate that a low dose of galanin has a nociceptive role at the spinal cord level mediated by GalR2 receptors, whereas the antiallodynic effect of high-dose galanin on neuropathic pain is mediated by the GalR1 receptors. Thus, a selective GalR1 agonist may be used to treat neuropathic pain.

On-column amperometric detection of ofloxacin and pasiniazid in urine by capillary electrophoresis with an improved fractured joint and small detection cell

An improved high-voltage electric field isolating joint and small detection cell have been carefully designed and fabricated. The joint possesses short steady time, high electric conductance efficiency and high performance. The cell is convenient to install and remove the capillaries with and without the joint, as well as to fix, adjust and insert the microelectrode into the detection capillary. Using the joint and the cell, an analytical method for determination of ofloxacin (Oflx) and pasiniazid (Ipa) in urine by capillary electrophoresis with on-column amperometric detection was developed. The calibration lines were linear in the range of 10-100 mg l-1 of Oflx and 1.0-50 mg l-1 of Ipa, respectively. The detection limits were 8.5 mg l-1 of Oflx and 0.80 mg l-1 of Ipa. Their recovery ranged from 101 to 104%. The accuracy and intra-day and inter-day reproducibility of Oflx and Ipa were determined with satisfactory results. This method was successfully used for determining Oflx and Ipa in human urine.

A mechanism for exon skipping caused by nonsense or missense mutations in BRCA1 and other genes

Point mutations can generate defective and sometimes harmful proteins. The nonsense-mediated mRNA decay (NMD) pathway minimizes the potential damage caused by nonsense mutations. In-frame nonsense codons located at a minimum distance upstream of the last exon-exon junction are recognized as premature termination codons (PTCs), targeting the mRNA for degradation. Some nonsense mutations cause skipping of one or more exons, presumably during pre-mRNA splicing in the nucleus; this phenomenon is termed nonsense-mediated altered splicing (NAS), and its underlying mechanism is unclear. By analyzing NAS in BRCA1, we show here that inappropriate exon skipping can be reproduced in vitro, and results from disruption of a splicing enhancer in the coding sequence. Enhancers can be disrupted by single nonsense, missense and translationally silent point mutations, without recognition of an open reading frame as such. These results argue against a nuclear reading-frame scanning mechanism for NAS. Coding-region single-nucleotide polymorphisms (cSNPs) within exonic splicing enhancers or silencers may affect the patterns or efficiency of mRNA splicing, which may in turn cause phenotypic variability and variable penetrance of mutations elsewhere in a gene.

[Studies of the mixoploid variation in banana micropropagated plants]

A special type of variation--the mixoploid variation, which had a great effect on the variation in the production of banana vitroplants, was reported for the first time. By means of examining chromosome, isozymes (EST, MDH, POX) and endogenous hormones (iPAs, IAA), the varied characters of the mixoploid varianties during the propagation in vitro when cultured as explant were investigated. The rate of the chromosome aberration in cells was characterized by starting at a much higher level and rising more rapidly in the preceding 15 subcultures as compared with the control. The rate of the isozyme variation was higher obviously than that of the control. The plantlets cloned in vitro from the mixoploid variant were also studied. The experiment showed that both the variant rates of chromosome and phenotype rose obviously. The mixoploid variant can cause the rate of variation to rise during the micropropagation.

Erhaia (Gastropoda: Rissooidea): phylogenetic relationships and the question of Paragonimus coevolution in Asia

The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoidea and Rissooidea. The question whether or not Paragonimus shows the same specificity of host-parasite coevolved relationship as the human blood fluke Schistosoma was inspired by the finding of two sympatric snail species as hosts for Paragonimus skrjabini in Fujian Province, China: Gammatricula and Erhaia. The former species can clearly be classified as Pomatiopsidae: Triculinae. The latter has previously been classified as Pomatiopsidae: Pomatiopsinae. However, this classification based on anatomical characteristics is uncertain. In order to obtain a robust phylogenetic hypothesis for Erhaia, we have studied three gene fragments from this taxon as well as from twelve related taxa. The data show that the species involved represent four families: Pomatiopsidae, Hydrobiidae, Cochliopidae (here raised to family status), and Amnicolidae. Erhaia fits securely into the Amnicolidae. This indicates that P. skrjabini has not coevolved with snail lineages. However, P. skrjabini has so far only been reported from rissooidean snails, whereas members of the Paragonimus westermani complex have only been found in ceritheoidean snails. The implication is that there is a host specificity on the superfamily level. However, Asian freshwater species of the Ceritheoidea and Rissooidea usually are not sympatric and often prefer different habitats. It is therefore possible that ecological niche partitioning plays the primary role for Paragonimus evolution.

Decreased GDNF mRNA expression in dorsal spinal cord of unilateral arthritic rat

It is now well established that nerve growth factor (NGF) plays a key role in inflammation-induced hyperalgesia. It was also reported that brain derived neurotrophic factor (BDNF), another member of neurotrophins, contributed to the pain pathway as a neurotransmitter in the CNS. The present work demonstrated a down-regulation of glial cell line-derived neurotrophic factor (GDNF) mRNA expression in dorsal spinal cord in complete Freund's adjuvant-induced unilateral arthritic rats serving as a chronic pain model. The fast occurring and long lasting down-regulations suggest that GDNF might contribute to pain pathway in a way different from neurotrophins and might play a role in the maintenance of chronic pain status.

On-column amperometric detection in capillary electrophoresis with an improved high-voltage electric field decoupler

An improved fabrication method for a decoupler for on-column amperometric detection in capillary electrophoresis (CE) is described. The decoupler is fabricated by etching one side-wall of the capillary with hydrofluoric acid after the polymer coating had been etched by laser, then the etched hole is sealed with adhesive. The steady time, electric conductivity efficiency and performance are investigated. On-column amperometric detection by CE of para-substituted phenols was carried out by coupling with a carbon-fiber microelectrode (10-microm diameter) and a practical small electrochemical detection cell.