Composition and strain measurements of Ge(Si)/Si(001) islands by HRTEM

The distributions of the composition and the strain in the Ge(Si)/Si(001) coherent islands grown by molecular-beam epitaxy are investigated by digital analysis of high resolution transmission electron microscopy (HRTEM) micrographs. Local composition and strain are obtained from the measurement of the lattice displacement based on the Poisson's formula and Vegard's law. The analysis suggests that the islands have high Ge content at the island's central region. The island is partially relaxed by the substrate deformation and strain concentrated around the edge of islands. The alloying of the islands was found due to the Si surface diffusion.

Formation mechanism of nanocrystalline high-pressure phases in silicon during nanogrinding

The phase transformations of Si under nanogrinding have been studied by transmission electron microscopy and Raman spectroscopy. Nanocrystalline high-pressure phases (Si-III/Si-XII) were found in the amorphous layer of the subsurface of heavily ground Si. The sequence of the phase transformation in nanogrinding has been found to be different to that in nanoindentation. The formation mechanism of the nanocrystalline high-pressure phases in nanogrinding is proposed based on experimental results.

Identification of a major quantitative trait locus conditioning resistance to greenbug biotype E in sorghum PI 550610 using simple sequence repeat markers

Greenbug, Schizaphis graminum (Rondani), represents the most important pest insect of sorghum, Sorghum bicolor (L.) Moench, in the Great Plains of the United States. Biotype E is the most widespread and dominant type not only in sorghum and wheat, Triticum aestivum L., fields, but also on many noncultivated grass species. This study was designed to determine sorghum accession PI 550610 resistance to greenbug biotype E, to map the resistance quantitative trait loci (QTLs) by using an established simple sequence repeat (SSR) linkage map and to identify SSR markers closely linked to the major resistance QTLs. In greenhouse screening tests, seedlings of PI 550610 showed strong resistance to the greenbug at a level similar to resistant accession PI550607. For QTL mapping, one F2 population containing 277 progeny and one population containing 233 F2:3 families derived from Westland A line x PI 550610 were used to genotype 132 polymorphic SSR markers and to phenotype seedling resistance to greenbug feeding. Phenotypic evaluation of sorghum seedling damage at 7, 12, 17, and 21 d postinfestation in the F2:3 families revealed that resistance variation was normally distributed. Single marker analysis indicated 16 SSRs spread over five chromosomes were significant for greenbug resistance. Composite interval and multiple interval mapping procedures indicated that a major QTL resided in the interval of 6.8 cM between SSR markers Xtxp358 and Xtxp289 on SBI-09. The results will be valuable in the development of new greenbug biotype E resistant sorghum cultivars and for the further characterization of major genes by map-based cloning.

An SSR genetic map of Sorghum bicolor (L.) Moench and its comparison to a published genetic map

Sorghum bicolor (L.) Moench is an important grain and forage crop grown worldwide. We developed a simple sequence repeat (SSR) linkage map for sorghum using 352 publicly available SSR primer pairs and a population of 277 F2 individuals derived from a cross between the Westland A line and PI 550610. A total of 132 SSR loci appeared polymorphic in the mapping population, and 118 SSRs were mapped to 16 linkage groups. These mapped SSR loci were distributed throughout 10 chromosomes of sorghum, and spanned a distance of 997.5 cM. More important, 38 new SSR loci were added to the sorghum genetic map in this study. The mapping result also showed that chromosomes SBI-01, SBI-02, SBI-05, and SBI-06 each had 1 linkage group; the other 6 chromosomes were composed of 2 linkage groups each. Except for 5 closely linked marker flips and 1 locus (Sb6_34), the marker order of this map was collinear to a published sorghum map, and the genetic distances of common marker intervals were similar, with a difference ratio <or= 0.05 between the 2 maps. The difference ratio is a new index developed in this study that can be used to compare the genetic distances of DNA markers between 2 maps. This SSR map carrying additional SSR markers will facilitate mapping quantitative trait loci to the sorghum genome and map-based gene cloning. Furthermore, the novel method for calculating distance between DNA markers will be a useful tool for the comparative analysis of genetic markers between linkage maps with different genetic backgrounds and the alignment of different sorghum genetic maps.

Genetic diversity of sorghum accessions resistant to greenbugs as assessed with AFLP markers

Sorghum, Sorghum bicolor (L.) Moench, is the fifth most important cereal crop grown worldwide and the fourth in the United States. Greenbug, Schizaphis graminum (Rondani), is a major insect pest of sorghum with several biotypes reported to date. Greenbug biotype I is currently the most prevalent and most virulent on sorghum plants. Breeding for resistance is an effective way to control greenbug damage. A successful breeding program relies in part upon a clear understanding of breeding materials. However, the genetic diversity and relatedness among the greenbug biotype I resistant accessions collected from different geographic origins have not been well characterized, although a rich germplasm collection is available. In this study, 26 sorghum accessions from 12 countries were evaluated for both resistance to greenbug biotype I and genetic diversity using fluorescence-labeled amplified fragment length polymorphism (AFLP). Twenty-six AFLP primer combinations produced 819 polymorphic fragments indicating a relatively high level of polymorphism among the accessions. Genetic similarity coefficients among the sorghum accessions ranged from 0.69 to 0.90. Cluster analysis indicated that there were two major groups based on polymorphic bands. This study has led to the identification of new genetic sources of sorghum with substantial genetic variation and distinct groupings of resistant accessions that have the potential for use in the development of durable greenbug resistant sorghum.

AFLP analysis of Cynodon dactylon (L.) Pers. var. dactylon genetic variation

Cynodon dactylon (L.) Pers. var. dactylon (common bermudagrass) is geographically widely distributed between about lat 45°N and lat 45°S, penetrating to about lat 53°N in Europe. The extensive variation of morphological and adaptive characteristics of the taxon is substantially documented, but information is lacking on DNA molecular variation in geographically disparate forms. Accordingly, this study was conducted to assess molecular genetic variation and genetic relatedness among 28 C. dactylon var. dactylon accessions originating from 11 countries on 4 continents (Africa, Asia, Australia, and Europe). A fluorescence-labeled amplified fragment length polymorphism (AFLP) DNA profiling method was used to detect the genetic diversity and relatedness. On the basis of 443 polymorphic AFLP fragments from 8 primer combinations, the accessions were grouped into clusters and subclusters associating with their geographic origins. Genetic similarity coefficients (SC) for the 28 accessions ranged from 0.53 to 0.98. Accessions originating from Africa, Australia, Asia, and Europe formed major groupings as indicated by cluster and principal coordinate analysis. Accessions from Australia and Asia, though separately clustered, were relatively closely related and most distantly related to accessions of European origin. African accessions formed two distant clusters and had the greatest variation in genetic relatedness relative to accessions from other geographic regions. Sampling the full extent of genetic variation in C. dactylon var. dactylon would require extensive germplasm collection in the major geographic regions of its distributional range.Key words: common bermudagrass, AFLP marker, genetic relatedness.

Isolation and Analysis of hupR Gene Required for the Expression of Hydrogenase in Rhodobacter sphaeroides

Cosmid 1 containing the hup genes isolated from the photosynthetic bacterium Rhodobacter sphaeroides was studied. The hupR gene from cosmid 1 was cloned and sequenced (EMBL accession number AJ243734). It encoded a 54.031 kD protein homologous to transcriptional regulators belonging to the superfamily of two-component regulatory systems. The HupR protein was overexpressed in Escherichia coli in the form of His6-tagged HupR. The cloned hupR gene could restore hydrogenase activity in R.sphaeroides hupR mutants and activate hupSL gene transcription.

Loss of heterozygosity of the putative prostate cancer susceptibility gene HPC2/ELAC2 is uncommon in sporadic and familial prostate cancer

The recognition that prostate cancer clusters within families has led to the search for prostate cancer susceptibility genes. Recently, the HPC2/ELAC2 gene on chromosome 17p has been identified as a potential prostate cancer predisposition gene using both family based as well as case-control studies. Many cancer susceptibility genes act as tumor suppressor genes in which inactivation of one allele in the tumor can be detected via loss of heterozygosity (LOH). To determine whether the HPC2/ELAC2 gene demonstrates significant LOH in sporadic and familial prostate cancers, paired tumor and normal DNA samples were isolated using microdissection techniques from 44 radical prostatectomy specimens. Cases were analyzed using a panel of markers in the following order: TP53-D17S969-D17S947-(HPC2/ELAC2)-D17S799-D17S936. LOH was observed in < 10% of cases using the four markers that map to the HPC2/ELAC2 region. However, allelic loss was observed at the TP53 gene in 25% of informative cases. Taken together, inactivation of the HPC2/ELAC2 gene via LOH is a relatively uncommon event in prostate cancer. Future studies will determine whether 17p LOH occurs in the subset of patients with an inherited mutation in HPC2/ELAC2.

Loss of the potassium channel beta-subunit gene, KCNAB2, is associated with epilepsy in patients with 1p36 deletion syndrome

PURPOSE

Clinical features associated with chromosome 1p36 deletion include characteristic craniofacial abnormalities, mental retardation, and epilepsy. The presence and severity of specific phenotypic features are likely to be correlated with loss of a distinct complement of genes in each patient. We hypothesize that hemizygous deletion of one, or a few, critical gene(s) controlling neuronal excitability is associated with the epilepsy phenotype. Because ion channels are important determinants of seizure susceptibility and the voltage-gated K(+) channel beta-subunit gene, KCNAB2, has been localized to 1p36, we propose that deletion of this gene may be associated with the epilepsy phenotype.

METHODS

Twenty-four patients were evaluated by fluorescence in situ hybridization with a probe containing KCNAB2. Clinical details were obtained by neurologic examination and EEG.

RESULTS

Nine patients are deleted for the KCNAB2 locus, and eight (89%) of these have epilepsy or epileptiform activity on EEG. The majority of patients have a severe seizure phenotype, including infantile spasms. In contrast, of those not deleted for KCNAB2, only 27% have chronic seizures, and none had infantile spasms.

CONCLUSIONS

Lack of the beta subunit would be predicted to reduce K(+) channel-mediated membrane repolarization and increase neuronal excitability, suggesting a possible relation between loss of this gene and the development of seizures. Because some patients with seizures were not deleted for KCNAB2, there may be additional genes within 1p36 that contribute to epilepsy in this syndrome. Hemizygosity of this gene in a majority of monosomy 1p36 syndrome patients with epilepsy suggests that haploinsufficiency for KCNAB2 is a significant risk factor for epilepsy.

Characterization of an ATP-dependent type I DNA ligase from Arabidopsis thaliana

Here we report the purification and biochemical characterization of recombinant Arabidopsis thaliana DNA ligase I. We show that this ligase requires ATP as a source for adenylation. The calculated Km [ATP] for ligation is 3 microM. This enzyme is able to ligate nicks in oligo(dT)/poly(dA) and oligo(rA)/poly(dT) substrates, but not in oligo(dT)/poly(rA) substrates. Double-stranded DNAs with cohesive or blunt ends are also good substrates for the ligase. These biochemical features of the purified enzyme show the characteristics typical of a type I DNA ligase. Furthermore, this DNA ligase is able to perform the reverse reaction (relaxation of supercoiled DNA) in an AMP-dependent and PPi-stimulated manner.

Identification of a human brain-specific gene, calneuron 1, a new member of the calmodulin superfamily

The calmodulin superfamily includes the calmodulins, calcium-binding proteins, and related genes. Herein, we describe the cloning and characterization of human calneuron 1 (CALN1). CALN1 encodes a novel neuron-specific protein that maps to chromosome 7q11. CALN1 spans a large genomic region (>360 kb). Sequence comparison shows significant similarity with the calmodulin superfamily of genes, especially in the two conserved EF-hand motifs. The mouse orthologous gene (Caln1) shows little prenatal expression, with highest expression at Postnatal Day 21. In situ hybridization to adult mouse brain shows high expression in the cerebellum, hippocampus, and cortex. The high expression of this gene exclusively in brain, the developmental changes in expression levels, the high homology with calmodulin which indicates a potential role in signal transduction, and the cellular localization of the mRNA suggest that CALN1 has a significant role in the physiology of neurons and is potentially important in memory and learning.

[Expression of single-chain Fv antibody for anti-beet necrotic yellow vein virus in Escherichia coli]

The heavy chains variable region gene (VH) of monoclonal antibody against beet necrotic yellow vein virus (BNYVV) was amplified from total DNA extracted from anti-BNYVV hybridoma cells by PCR. Sequencing showed that the VH belongs to mouse subgroup II(A) and contains 360 bp, which code one hundred and twenty amino acids. The VH and VL genes were inserted into a plasmid which contains a linker sequence for constructing scFv gene. The new vector named pTC scFv. The scFv was produced in Escherichia coli and appeared binding activity with BNYVV antigen by ELISA method.

[Studies of the genetic polymorphism of Schistosoma japonicum (Chinese mainland strains)]

In order to analyze the interspecies diversity and the extent of diversity among Schistosoma japonicum Chinese mainland strains, the genetic variation on gene level among 6 isolates collected from Jiangxi, Hunan, Hubei, Anhui, Sichuan, Yunnan and a cultured isolate from a laboratory were studied using molecular biological technique. There were only two different bases at position 112 and 143 in 536 bp sequence of 28S rDNA-D2 domain between Anhui and Yunnan isolates, the homology was 99.6%. The result could be explained the reason of why the migration rates of single chain 28S rDNA-D2 domain among the above 7 isolates were the same completely in PCR-SSCP. However, comparing with the sequences of the Philippine isolate of S. japonicum, S. mansoni and S. aematobium, there were 6, 94 and 93 different bases and the homologies were 98.9, 82.5 and 82.7 per cent separately. With 8 restriction endonucleases to analyze the ITS of rDNA obtained by PCR from the 7 isolates, the results showed that only 3 minor bands were different, e.g. 5.3% of total 58 fragments. It was suggested that the ITS of rDNA among 7 isolates were highly conserved. Using randomly amplified polymorphic DNA (RAPD) to analyze the genetic diversity of the genomes of the 7 isolates, the average genetic distance (D) calculated from total 284 amplified fragments was 0.22. The maximum D was 0.30 and existed between Anhui and Yunnan isolates. The minimum D was 0.13 and existed between Sichuan and Yunnan isolates. The clustering analysis of genetic distances showed that the 7 isolates could be gathered in one group. From above three results, it could be considered that the genetic diversity on gene level among S. japonicum Chinese mainland strains was very low.

[Embolization in arteriovenous malformations of maxillofacial region with PVA]

OBJECTIVE

To evaluate the embolization of arteriovenous malformations of the maxillofacial region with PVA.

METHODS

8 cases (male:3, female:5) of arteriovenous malformations of the maxillofacial region comprised this study group. The embolic material used was PVA (Polyvinyl Alcohol Foam) particles (250-500 microm) injected using 4.0 to 3.0 French-size catheters, catheterized selectively in the feeding pedicles of the AVM under the guidance of DSA machine (PHILIPS V3000).

RESULTS

Five patients were embolized an a single session, and three patients needed two sessions. Immediate angiographical results showed total disappearance of the AVMs in all patients. Swelling, pulsation, and bruit were disappeared after embolization. Pericoronal oozing of blood and acute arterial bleeding was controllable. Local pain, swelling,and low-grade fever usually lasted from 3 to 7 days after embolization.

CONCLUSION

The embolization of arteriovenous malformations of the maxillofacial region with PVA is effective and safe, and the longer follow-up is expected.

The expression of E-cadherin-catenin complex in adenoid cystic carcinoma of salivary glands

OBJECTIVE

The aim of this study was to investigate the expression of the E-cadherin-catenin (E-cad-cat) complex in human salivary adenoid cystic carcinoma (ACC) and determine the effects of E-cad-cat expression on tumor differentiation, metastasis, and invasion, as well as its clinical significance.

METHODS

The expression of adhesion molecules, which included E-cadherin, alpha-catenin, and beta-catenin, on 10 cases of normal salivary glands, and 50 cases of human salivary ACC were investigated by immunohistochemistry.

RESULTS

Strong and stable expression of E-cad-cat complex showed in normal salivary glands tissues. However, weaker expression and even complete absence, of the positive signals were shown on all ACC cases. Coexpression of E-cad-cat were detected in 29 (58%) of the 50 ACC specimens. Positive staining of E-cad-cat complex were detected in 7 (39%) of the 18 ACC primary sites that had aggressive phenotype of nerve and vasculature.

CONCLUSION

Strong positive signals of E-cad-cat complex are shown in normal salivary glands, and the down-regulated expression were observed in ACC cases. The expression of E-cad-cat complex is associated with a more aggressive phenotype on nerve and vasculature. No association with various histopathologic subtypes was found. However, absent or low E-cad expression was observed more frequently in solid carcinomas than in cribriform or tubular carcinomas. Down-regulation of E-cad-cat complex may be associated with canceration of normal salivary glands. The expression levels of E-cad-cat were positively correlated to the differentiation of ACC tumor cells.

Clusterin protein diversity in the primate eye

PURPOSE

The clusterin gene encodes a multi-functional protein that has been identified in different tissues, including a number of different eye tissues, primarily in the mouse and to a much lesser extent in humans. Clusterin has been implicated in a number of cellular processes such as lipid transport, membrane integrity, apoptosis, and neurodegeneration, all of which could be important to the biology of the eye. In the current communication, we provide data that confirms the expression of clusterin in a number of different human eye tissues and establishes the expression profile of this gene in monkey derived eye tissues. The issue that we sought to examine is whether a broad profile of clusterin expression in the eye is consistent in primates (monkey and human).

METHODS

The majority of our study was done using monkey eye tissues. Where possible, we have used human tissues in order to confirm published findings. Northern and western analysis was performed using tissues derived from monkey eyes. In situ hybridization and immunochemistry were carried out on human eye sections.

RESULTS

Clusterin mRNA is expressed in primate lens, cornea, limbus, sclera, orbital muscle, ciliary body, retina, RPE/choroid, and RPE cells in culture. Western analysis revealed that two major groups of clusterin exist in the eye, a high molecular weight group (>100 kDa) and a second group consisting of at least five clusterin species that are all approximately 80 kDa. Analysis of conditioned media from RPE cells cultured on permeable supports suggests that different forms of clusterin display alternative patterns of secretion.

CONCLUSIONS

Clusterin is expressed in a broad range of eye tissues in both human and monkey, suggesting that this is a characteristic feature in primates. We demonstrate for the first time that a diverse number of clusterin isoforms were observed in monkey eye tissues by western analysis. Meanwhile, the molecular size of clusterin mRNA detected in the array of tissues are identical in size, suggesting that the nature of the diversity in clusterin forms is due to post-translational modifications. In addition, new insights were made in defining clusterin expression in ciliary body, cornea, and the retinal pigment epithelium.

[Studies on single cell cloning of Ginkgo biloba L]

OBJECTIVE

To investigate the relations of the productivity stability of to the homogenization of Ginkgo biloba cells by single cell clones.

METHOD

Using plant single cell plate culture technique.

RESULTS

Adding 500 ml.L-1L-glutamine in the medium increased greatly the cell plating efficiency (PE), and within the range 0.5-5.0 x 10(4) Cell.ml-1 of the initial cell density, the PE increased with the increment of the cell density. Of the 48 cell clones obtained, the GKB content in G-22 clone reached 0.099%; and most of the clones remain stable in growth and GKB production during subcultures.

CONCLUSION

During the cell and tissue culture of G. biloba, the application of plant single cell cloning technique helps to a certain extent solve the problem of productivity instability of ginkgolide.

Acarbose partially inhibits microvascular retinopathy in the Zucker Diabetic Fatty rat (ZDF/Gmi-fa)

We compared quantitative capillary retinopathic changes between non-insulin-dependent diabetic Zucker Diabetic Fatty (ZDF) rats and heterozygous nondiabetic Zucker controls and evaluated the effect of an orally administered glucosidase inhibitor, acarbose, on retinopathy in these animals. Four groups of eight rats were analyzed: treated and untreated ZDF and treated and untreated Zuckers. Retinal capillary basement membrane thickening and retinal capillary cell density were determined from transmission electron microscopy and trypsin digestion preparations. ZDF rats had thicker basement membranes (p<0.0001) and more cells per unit capillary length (p=0.0003) compared to Zuckers. Acarbose treatment significantly reduced basement membrane thickening in the treated ZDF rats (p=0.001), but the effects on cell density showed only a favorable trend. Acarbose treatment has an ameliorative effect on the development of microvascular retinopathy in the ZDF rat, probably due to lessening of hyperglycemia.

[Effects of culture conditions on callus growth and taxol formation of Taxus yunnanensis Cheng et L.K.Fu]

OBJECTIVE

To seek culture conditions suitable for the callus growth and taxol formation of Taxus yunnanensis.

METHOD

Determining the growth index and taxol content in the callus cultured under different illumination conditions or on different media.

RESULTS AND CONCLUSION

Darkness, the combination of 0.1 mg.L-1BAP and 2,4-D 1.0 mg.L-1, and B5, DCR or 6,7-V basal medium were favorable for the callus growth and taxol formation of Taxus yunnanensis; high NO3- concentration in the medium promoted callus growth, and high NH4+ concentration greatly inhibited callus growth, but dramatically increased taxol content.

Prostacyclin-induced relaxations of small porcine pulmonary arteries are enhanced by the basal release of endothelium-derived nitric oxide through an effect on cyclic GMP-inhibited-cyclic AMP phosphodiesterase

AIM

To study the interactions between prostacyclin and endothelium-derived nitric oxide in porcine pulmonary arteries.

METHODS

Rings of 5th order of porcine pulmonary arteries were studied in vitro for the measurement of tension and the content in cyclic nucleotides.

RESULTS

Prostacyclin, given exogenously, caused endothelium-potentiated relaxations (inhibition of phenylephrine contraction) that were inhibited by the inhibitors of the L-arginine nitric oxide pathway, oxyhemoglobin and N omega-nitro-L-arginine. These inhibitors did not affect the tension in rings without endothelium. Cyclic GMP-concentrations were not increased above basal concentrations in the presence of prostacyclin. Increases were seen with acetylcholine and sodium nitroprusside. Prostacyclin-stimulated cyclic AMP concentrations did not reach statistical significance compared to controls. The addition of 8-bromo-cyclic GMP to prostacyclin, however, increased the cyclic AMP content. The nitric oxide synthase inhibitor, nitro-L-arginine (NLA), reduced the prostacyclin-stimulated cyclic AMP content to basal level. Inhibition of cyclic GMP-inhibited cyclic AMP phosphodiesterase by 8-bromo-cyclic GMP or amrinone (a specific inhibitor of this enzyme) potentiated the prostacyclin-induced relaxations in rings without endothelium to a magnitude similar to that observed in rings with endothelium.

CONCLUSION

These data suggest that the augmentation by the endothelium of the prostacyclin-induced relaxation of porcine pulmonary arteries is secondary to the inhibition of cyclic GMP-inhibited cyclic AMP phosphodiesterase by basally released endothelium-derived nitric oxide.

[The expression of adhesion molecules in human salivary adenoid cystic carcinoma cell line]

OBJECTIVE:The aim of this study was to investigate the expression of the adhesion molecules in human salivary adenoid cystic carcinoma(ACC) cell lines (ACC-2 line and ACC-M strain) which had different metastatic ability.METHODS:The expression of adhesion molecules,which included CD44s,CD44v6,E cadherin,alph-catenin and beta-catenin in two human salivary ACC cell lines and Scid mice neoplasm models was investigated by immunohistochemistry. RESULTS: (1)Positive staining of adhesion molecules in lung metastatic foci of ACC was higher than that in subcutaneous implanted tumor mass.(2)The growing of ACC-M was slower in the cells of abdominal cavity implanted tumor,and also the differentiation of the former was better than the latter.(3)Weaker Positive staining of CD44v6 in ACC cells in vitro was showed,however,no positive staining was detected in lung metastatic foci cells of ACC M and the cells of subcutaneous tumor.CONCLUSION: The expression of CD44s in ACC cells was influenced by cell differentiation,and may affect the growth conditions;The expression levels of E cad/cat was positively correlative to the differentiation of ACC tumor cells;No significant correlation was revealed between the expression of CD44v6 and metastatic ability of ACC.