[Correction Methods of Temperature Drift for Infrared Spectral Emissivity Measurement System].

For the influence of temperature drift of the spectral responsivity on the repeatability infrared spectral emissivity measurement system, a temperature drift correction method is proposed based on the polynomial fitting. By analyzing the function of detector output voltage depended on its temperature. After studying the functional relationship between the temperature and spectral responsivity of detector, the spectral response curve varies with temperature is fitted and get the fitting equation. Calculating the drift correction factor of spectral responsivity, the output voltage of infrared detector is corrected. The effect of spectral response drift on the output voltage of detector is eliminated. With the development of temperature drift correction device of spectral responsivity, the temperature drift curve of spectral response is measured. Compared to the exponential fitting, the fitting consistency of sixth-order polynomial curve is excellent. Because of the application of this method, the repeatability of spectral emissivity measurement system is improved.

Comparative validation of the D. melanogaster modENCODE transcriptome annotation.

Accurate gene model annotation of reference genomes is critical for making them useful. The modENCODE project has improved the D. melanogaster genome annotation by using deep and diverse high-throughput data. Since transcriptional activity that has been evolutionarily conserved is likely to have an advantageous function, we have performed large-scale interspecific comparisons to increase confidence in predicted annotations. To support comparative genomics, we filled in divergence gaps in the Drosophila phylogeny by generating draft genomes for eight new species. For comparative transcriptome analysis, we generated mRNA expression profiles on 81 samples from multiple tissues and developmental stages of 15 Drosophila species, and we performed cap analysis of gene expression in D. melanogaster and D. pseudoobscura. We also describe conservation of four distinct core promoter structures composed of combinations of elements at three positions. Overall, each type of genomic feature shows a characteristic divergence rate relative to neutral models, highlighting the value of multispecies alignment in annotating a target genome that should prove useful in the annotation of other high priority genomes, especially human and other mammalian genomes that are rich in noncoding sequences. We report that the vast majority of elements in the annotation are evolutionarily conserved, indicating that the annotation will be an important springboard for functional genetic testing by the Drosophila community.

Natural variation in genome architecture among 205 Drosophila melanogaster Genetic Reference Panel lines.

The Drosophila melanogaster Genetic Reference Panel (DGRP) is a community resource of 205 sequenced inbred lines, derived to improve our understanding of the effects of naturally occurring genetic variation on molecular and organismal phenotypes. We used an integrated genotyping strategy to identify 4,853,802 single nucleotide polymorphisms (SNPs) and 1,296,080 non-SNP variants. Our molecular population genomic analyses show higher deletion than insertion mutation rates and stronger purifying selection on deletions. Weaker selection on insertions than deletions is consistent with our observed distribution of genome size determined by flow cytometry, which is skewed toward larger genomes. Insertion/deletion and single nucleotide polymorphisms are positively correlated with each other and with local recombination, suggesting that their nonrandom distributions are due to hitchhiking and background selection. Our cytogenetic analysis identified 16 polymorphic inversions in the DGRP. Common inverted and standard karyotypes are genetically divergent and account for most of the variation in relatedness among the DGRP lines. Intriguingly, variation in genome size and many quantitative traits are significantly associated with inversions. Approximately 50% of the DGRP lines are infected with Wolbachia, and four lines have germline insertions of Wolbachia sequences, but effects of Wolbachia infection on quantitative traits are rarely significant. The DGRP complements ongoing efforts to functionally annotate the Drosophila genome. Indeed, 15% of all D. melanogaster genes segregate for potentially damaged proteins in the DGRP, and genome-wide analyses of quantitative traits identify novel candidate genes. The DGRP lines, sequence data, genotypes, quality scores, phenotypes, and analysis and visualization tools are publicly available.

Epistasis dominates the genetic architecture of Drosophila quantitative traits.

Epistasis-nonlinear genetic interactions between polymorphic loci-is the genetic basis of canalization and speciation, and epistatic interactions can be used to infer genetic networks affecting quantitative traits. However, the role that epistasis plays in the genetic architecture of quantitative traits is controversial. Here, we compared the genetic architecture of three Drosophila life history traits in the sequenced inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and a large outbred, advanced intercross population derived from 40 DGRP lines (Flyland). We assessed allele frequency changes between pools of individuals at the extremes of the distribution for each trait in the Flyland population by deep DNA sequencing. The genetic architecture of all traits was highly polygenic in both analyses. Surprisingly, none of the SNPs associated with the traits in Flyland replicated in the DGRP and vice versa. However, the majority of these SNPs participated in at least one epistatic interaction in the DGRP. Despite apparent additive effects at largely distinct loci in the two populations, the epistatic interactions perturbed common, biologically plausible, and highly connected genetic networks. Our analysis underscores the importance of epistasis as a principal factor that determines variation for quantitative traits and provides a means to uncover genetic networks affecting these traits. Knowledge of epistatic networks will contribute to our understanding of the genetic basis of evolutionarily and clinically important traits and enhance predictive ability at an individualized level in medicine and agriculture.

The Drosophila melanogaster Genetic Reference Panel.

A major challenge of biology is understanding the relationship between molecular genetic variation and variation in quantitative traits, including fitness. This relationship determines our ability to predict phenotypes from genotypes and to understand how evolutionary forces shape variation within and between species. Previous efforts to dissect the genotype-phenotype map were based on incomplete genotypic information. Here, we describe the Drosophila melanogaster Genetic Reference Panel (DGRP), a community resource for analysis of population genomics and quantitative traits. The DGRP consists of fully sequenced inbred lines derived from a natural population. Population genomic analyses reveal reduced polymorphism in centromeric autosomal regions and the X chromosome, evidence for positive and negative selection, and rapid evolution of the X chromosome. Many variants in novel genes, most at low frequency, are associated with quantitative traits and explain a large fraction of the phenotypic variance. The DGRP facilitates genotype-phenotype mapping using the power of Drosophila genetics.

[Effects of Tiam1 on invasion and metastasis of breast carcinoma and its mechanisms].

OBJECTIVE: To investigate the significance of Tiam1 in invasion and metastasis of breast carcinoma and its mechanisms. METHODS: Immunohistochemistry was used to detect Tiam1 expression in tumor tissue of 126 breast carcinomas. Tiam1 was silenced by siRNA in breast carcinoma cell line MDA-MB-435, then the expressions of phosphor-ERK 1, ERK 2 and VEGF were detected, and electrophoretic mobility shift assay (EMSA) was used to examine the transcription activiy of AP-1. RESULTS: There was a significant relationship between Tiam1 expression and lymph node metastasis (P < 0.05). Furthermore, after silencing of Tiam1, the expressions of phosphor-ERK 1, ERK 2 and VEGF were decreased, and the transcription activity of AP-1 was down-regulated in the MDA-MB-435 cells. CONCLUSION: Tiam1 is closely related with invasion and metastasis of breast carcinoma, and the cascade Tiam1 through ERK, AP-1 and VEGF pathways may play an important role in enhancing angiogenesis, therefore, to promote invasion and metastasis of breast carcinoma.

Whole-exome sequencing identifies compound heterozygous mutations in WDR62 in siblings with recurrent polymicrogyria.

Polymicrogyria is a disorder of neuronal development resulting in structurally abnormal cerebral hemispheres characterized by over-folding and abnormal lamination of the cerebral cortex. Polymicrogyria is frequently associated with severe neurologic deficits including intellectual disability, motor problems, and epilepsy. There are acquired and genetic causes of polymicrogyria, but most patients with a presumed genetic etiology lack a specific diagnosis. Here we report using whole-exome sequencing to identify compound heterozygous mutations in the WD repeat domain 62 (WDR62) gene as the cause of recurrent polymicrogyria in a sibling pair. Sanger sequencing confirmed that the siblings both inherited 1-bp (maternal allele) and 2-bp (paternal allele) frameshift deletions, which predict premature truncation of WDR62, a protein that has a role in early cortical development. The probands are from a non-consanguineous family of Northern European descent, suggesting that autosomal recessive PMG due to compound heterozygous mutation of WDR62 might be a relatively common cause of PMG in the population. Further studies to identify mutation frequency in the population are needed.

[Ultraviolet spectrum analysis methods for detecting the concentration of organic pollutants in water].

The absorption rate of ultraviolet could be used to measure the concentration of organic pollutant, as most of the organic pollutant has stronger absorption rate in ultraviolet region in water. In the present paper, principal component regression (PCR), partial least squares (PLS), and support vector machine (SVM) were respectively used to model a regression model after the spectrum preprocessing, such as smoothing, derivation, standard normal variate transformation (SNV), etc. Then, the concentration of organic pollutant could be measured via the ultraviolet spectrum and the regression model. In the experiments, a group of water samples from the wastewater treatment process were used to verify the effects of the various preprocessing and modeling approaches. The results showed that for the good spectrum data, direct modeling without the spectrum pretreatment could be used since the pretreatment would worsen the results. LSSVM approach is more applicable in the case of small-size samples.

Whole exome capture in solution with 3 Gbp of data.

We have developed a solution-based method for targeted DNA capture-sequencing that is directed to the complete human exome. Using this approach allows the discovery of greater than 95% of all expected heterozygous singe base variants, requires as little as 3 Gbp of raw sequence data and constitutes an effective tool for identifying rare coding alleles in large scale genomic studies.

[Expression of Tiam1 in breast carcinomas and its clinical significance].

OBJECTIVE: To investigate the expression of T lymphoma invasion and metastasis inducing factor 1 (Tiam1) in breast carcinomas, and explore its association with the clinicopathological features of breast carcinoma. METHODS: Immunohistochemistry was used to detect Tiam1 expression in normal breast tissue and 126 breast carcinoma tissues, and the expression levels of Tiam1 mRNA and protein were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting, respectively. RESULTS: The expression of Tiam1 was significantly higher in breast carcinomas than in normal breast tissue (P<0.05). Tiam1 expression was not correlated to the age of the patients or the histological type (P>0.05), but to lymph node metastasis and clinical stages of the tumor (P<0.01). Tiam1 mRNA and protein expressions were stronger in breast carcinoma cell line MDA-MB-435 with high metastatic potential than in breast carcinoma cell line MCF-7. CONCLUSION: Tiam1 is closely related to the metastasis of breast carcinoma, and may play an important role in promoting metastasis of breast carcinoma.

Allele-specific methylation of a functional CTCF binding site upstream of MEG3 in the human imprinted domain of 14q32.

The gene MEG3 is located in the imprinted human chromosomal region on 14q32. Imprinting of a structurally homologous region IGF2/H19 on 11p15 is mediated through cytosine methylation-controlled binding of the protein CTCF to target sites upstream of H19. We identified five new CTCF binding sites around the promoter of MEG3. Using an electrophoretic mobility shift assay, we showed that these sites bind CTCF in vitro. Using one of these sites, chromatin immunoprecipitation (ChIP) analysis confirmed CTCF binding in-vivo, and differential allele-specific methylation was demonstrated in seven individuals with either maternal or paternal uniparental disomy 14 (UPD14). The site was unmethylated on the maternally inherited chromosomes 14 and methylated on the paternally inherited chromosomes 14, suggesting parent-specific methylation of sequences upstream of MEG3. We speculate that this CTCF-binding region may provide a mechanism for the transcriptional regulation of MEG3 and DLK1.

[Expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in the hepatocellular carcinomas].

OBJECTIVE: To explore the expression and clinical prognostic significance of matrix metalloproteinase-2 mRNA (MMP-2 mRNA), tissue inhibitor of matrix metalloproteinase-2 mRNA (TIMP-2 mRNA), matrix metalloproteinase-2 protein (MMP-2), matrix metalloproteinase-9 protein (MMP-9), tissue inhibitor of matrix metalloproteinase-1 protein (TIMP-1), and tissue inhibitor of matrix metalloproteinase-2 protein (TIMP-2) in the hepatocellular carcinomas (HCCs). METHODS: Fifty-six specimens of HCCs from 56 patients, who were followed-up, were investigated by in situ hybridization with specific probes for MMP-2, TIMP-2, and by immunohistochemistry with anti-MMP-2, MMP-9 and anti-TIMP-1, TIMP-2 monoclonal antibody. We analyzed the data with chi-square test, spearmans correlation analysis, monovariate Kaplan-Meier plot and multivariate Cox regression analysis. RESULTS: 1. The positive expression of MMP-2mRNA, TIMP-2mRNA, MMP-2 protein, MMP-9 protein, TIMP-1 protein and TIMP-2 protein in the 56 HCCs cases were 48 (85.7%), 35 (62.5%), 44 (78.6%), 41 (73.2%), 30 (53.6%), and 38 (68%), respectively. 2. We found over-expression of MMP-2 mRNA, MMP-2 protein, and MMP-9 protein, but low expression of TIMP-1 protein in the 56 cases of HCCs (P < 0.01, P < 0.05). 3. There was a positive association between TIMP-2mRNA and TIMP-2 protein expression, and between MMP-2 mRNA and MMP-2 protein in HCCs, respectively (r = 0.316, P < 0.05; r = 0.356, P < 0.05). 4. Over-expression of MMP-2 mRNA was positively correlated to the tumor size and TNM classification (r = 0.441, P < 0.001; r = 0.340, P < 0.05), and MMP-9 protein was related to shortened survival (P < 0.05). 5. In both monovariate Kaplan-Meir plot and multivariate Cox regression analysis, the expression of MMP-2 protein and MMP-9 protein were linked to unfavorable prognosis. These results were further confirmed by multivariate analysis in which MMP-2 protein and MMP-9 protein emerged as independent prognostic factors for poor survival regardless of the age, tumor size, tumor grades, TNM classification and expression of MMP-2mRNA, TIMP-2mRNA, TIMP-1 protein and TIMP-2 protein. The hazard ratios of expression of MMP-2 protein and MMP-9 protein were 3.875 and 4.528, respectively. CONCLUSION: The over-expression of MMP-2mRNA, MMP-2 protein and MMP-9 protein and the imbalance between MMP-2 and TIMP-2 play pivotal roles in the degradation of excellular matrix of HCCs. MMP-2 and MMP-9 immunoreactive protein have been closely related to a shortened survival independent of major prognostic indicators in the primary HCC and increase the risk of the patients after the operation.

Somatostatin receptor gene transfer inhibits established pancreatic cancer xenografts.

BACKGROUND: Most human pancreatic adenocarcinoma cells do not express somatostatin receptors, and somatostatin does not inhibit the growth of these cancers. We have demonstrated previously that somatostatin inhibits the growth of pancreatic cancers expressing somatostatin receptor subtype-2 (SSTR2), but not receptor-negative cancers. SSTR2 expression may be an important tumor-suppressor pathway that is lost in human pancreatic cancer. We hypothesized that SSTR2 gene transfer would restore the growth-inhibitory response of human pancreatic cancer to somatostatin. MATERIALS AND METHODS: Palpable human pancreatic adenocarcinoma tumors were established on the backs of nude mice by subcutaneous injection of cultured cells (Panc-1). The animals were divided into 5 groups (n = 10/group). Group I served as an untreated control. Group II received an intramuscular injection of the long-acting somatostatin analogue Sandostatin LAR. Group III received Lac-Z expressing adenovirus via intraperitoneal injection. Group IV received SSTR2 expressing adenovirus via intraperitoneal injection. Group V received SSTR2 expressing adenovirus via intraperitoneal injection and an intramuscular injection of Sandostatin LAR. The rate of tumor growth was assessed with calipers. After 28 days, the animals were anesthetized and exsanguanated, and the tumors were excised and weighed. Plasma somatostatin and octreotide levels were measured by radioimmunoassay. Expression of cell-surface somatostatin-receptor protein and known tumor-suppressor proteins was determined by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry. RESULTS: Systemic delivery of SSTR2-expressing adenovirus by intraperitoneal injection resulted in expression of SSTR2 protein in the subcutaneous human pancreatic cancers. Final tumor weight was significantly decreased in the groups expressing SSTR2 receptors compared to the other 3 groups. Treatment with Sandostatin LAR increased plasma octreotide levels as determined by radioimmunoassay, but had no significant effect on tumor growth. Western blot analysis revealed an up-regulation of the cyclin-dependent kinase inhibitors p27 and p16 in the SSTR2 transfected tumors. CONCLUSIONS: Expression of SSTR2 by human pancreatic cancer causes significant slowing of tumor growth by a mechanism independent of exogenous somatostatin. The mechanism may involve up-regulation of known tumor-suppressor proteins. Restoration of SSTR2 gene expression deserves further study as a potential gene-therapy strategy in human pancreatic cancer.

Refinement of the genomic structure of STX1A and mutation analysis in nondeletion Williams syndrome patients.

Williams syndrome (WS) is a contiguous gene deletion disorder in which the commonly deleted region contains at least 17 genes. One of these genes, Syntaxin 1A (STX1A), codes for a protein that is highly expressed in the nervous system and is essential for the docking of synaptic vesicles with the presynaptic plasma membrane. In this study, we refine the complete genomic structure of the human STX1A gene by direct sequencing and primer walking of bacterial artificial chromosome (BAC) clones and show that STX1A contains at least 10 exons and 9 introns. The length of exons range from 27 bp to 138 bp and all splice sites conform to the GT-AG rule. Investigation of the STX1A gene sequence in five WS patients without detectable deletions did not identify any point mutations. Although the regulatory elements that control STX1A transcription were not examined, these results do not support a role for STX1A in the WS phenotype.

A case of segmental paternal isodisomy of chromosome 14.

Uniparental disomy of chromosome 14 (UPD 14) results in one of two distinct abnormal phenotypes, depending upon the parent of origin. This discordance may result from the reciprocal over-expression and/or under-expression of one or more imprinted genes. We report a case of segmental paternal isodisomy for chromosome 14 with features similar to those reported in other paternal disomy 14 cases. Microsatellite marker analysis revealed an apparent somatic recombination event in 14q12 leading to proximal biparental inheritance, but segmental paternal uniparental isodisomy distal to this site. Analysis of monochromosomal somatic cell hybrids containing either the paternally inherited or the maternally inherited chromosome 14 revealed no deletion of the maternally inherited chromosome 14 and demonstrated the presence of paternal sequences from D14S121 to the telomere on both chromosomes 14. Thus, the patient has paternal isodisomy for 14q12-14qter. Because the patient shows most of the features associated with paternal disomy 14, this supports the presence of the imprinted domain(s) distal to 14q12 and suggests that the proximal region of chromosome 14 does not contain imprinted genes that contribute significantly to the paternal UPD 14 phenotype.