Cloning and Heterologous Expression of a Novel Xylanase Gene TAX1 from Trichoderma atroviride and Its Application in the Deconstruction of Corn Stover.

Xylanase plays a vital role in the efficient utilization of xylan, which accounts for up to 30% of plant dry matter. However, the production cost of xylanase remains high, and the enzymatic characteristics of xylanases of most microorganisms are not suitable for industrial production. Therefore, it is of great significance to discover and develop new and efficient xylanases. In this study, the xylanase gene TAX1 (672 bp cDNA) was cloned from Trichoderma atroviride 3.3013 and expressed in Pichia pastoris. The TAX1 gene encoded a 223-amino acid protein (TAX1) with a molecular weight of 24.2 kDa which showed high similarity to glycoside hydrolase family 11. Enzyme activity assay verified that the recombinant xylanase TAX1 had optimal activity (215.3 IU/mL) at 50°C and pH 6.0. Stable working conditions were measured as pH 4.0-7.0 and 40-60°C. By adding Zn2+, the relative enzymatic activity of recombinant TAX1 was enhanced by 26%. The recombinant xylanase showed high activity toward birchwood xylan and corn stover. The Km and Kcat for xylan and corn stover were 0.36 mg/mL and 0.204 S-1 and 0.48 mg/mL and 0.149 S-1, respectively. The enzymatic activity of the TAX1 produced by P. pastoris was about 2.4-4 times higher that directly isolated from T. atroviride, so engineered P. pastoris for xylanase production could be an ideal candidate for industrial enzyme production.

The α-Subunit of the Chloroplast ATP Synthase of Tomato Reinforces Resistance to Gray Mold and Broad-Spectrum Resistance in Transgenic Tobacco.

Chloroplast ATP synthase (cpATPase) is responsible for ATP production during photosynthesis. Our previous studies showed that the cpATPase CF1 α subunit (AtpA) is a key protein involved in Clonostachys rosea-induced resistance to the fungus Botrytis cinerea in tomato. Here, we show that expression of the tomato atpA gene was upregulated by B. cinerea and Clonostachys rosea. The tomato atpA gene was then isolated, and transgenic tobacco lines were obtained. Compared with untransformed plants, atpA-overexpressing tobacco showed increased resistance to B. cinerea, characterized by reduced disease incidence, defense-associated hypersensitive response-like reactions, balanced reactive oxygen species, alleviated damage to the chloroplast ultrastructure of leaf cells, elevated levels of ATP content and cpATPase activity, and enhanced expression of genes related to carbon metabolism, photosynthesis, and defense. Incremental Ca2+ efflux and steady H+ efflux were observed in transgenic tobacco after inoculation with B. cinerea. In addition, overexpression of atpA conferred enhanced tolerance to salinity and resistance to the fungus Cladosporium fulvum. Thus, AtpA is a key regulator that links signaling to cellular redox homeostasis, ATP biosynthesis, and gene expression of resistance traits to modulate immunity to pathogen infection and provides broad-spectrum resistance in plants in the process.

Morphological and anatomical characteristics of exserted stigma sterility and the location and function of SlLst (Solanum lycopersicum Long styles) gene in tomato.

KEY MESSAGE: Anatomical changes in and hormone roles of the exserted stigma were investigated, and localization and functional analysis of SlLst for the exserted stigma were performed using SLAF-BSA-seq, parental resequencing and overexpression of SlLst in tomato. Tomato accession T431 produces stigmas under relatively high temperatures (> 27 °C, the average temperature in Harbin, China, in June-August), so pollen can rarely reach the stigma properly. This allows the percentage of male sterility exceed 95%, making the use of this accession practical for hybrid seed production. To investigate the mechanism underlying the exserted stigma male sterility, the morphological changes of, anatomical changes of, and comparative endogenous hormone (IAA, ABA, GA3, ZT, SA) changes in flowers during flower development of tomato accessions DL5 and T431 were measured. The location and function of genes controlling exserted stigma sterility were analyzed using super SLAF-BSA-seq, parental resequencing, comparative genomics and the overexpression of SlLst in tomato. The results showed that an increase in cell number mainly caused stigma exsertion. IAA played a major role, while ABA had an opposite effect on stigma exertion. Moreover, 26 candidate genes related to the exserted stigma were found, located on chromosome 12. The Solyc12g027610.1 (SlLst) gene was identified as the key candidate gene by functional analysis. A subcellular localization assay revealed that SlLst is targeted to the nucleus and cell membrane. Phenotypic analysis of SlLst-overexpressing tomato showed that SlLst plays a crucial role during stigma exsertion.

Creation of a robust and R-selective ω-amine transaminase for the asymmetric synthesis of sitagliptin intermediate on a kilogram scale.

The creation of an R-selective ω-amine transaminase (ω-ATA) as biocatalyst is crucial for the asymmetric amination of prochiral ketones to produce sitagliptin intermediates because rare ω-ATAs are R-selective in nature and most of them suffer from poor stability and low activity toward bulky prochiral ketones. Here, the gene of an R-selective ω-ATA was cloned from Arthrobacter cumminsii ZJUT212 (AcATA) and expressed in Escherichia coli. The best variants (M1 + M122H and M1+T134 G) were obtained using a semi-rational protein design after screening. These variants not only exhibited improved activity and substrate affinity but also enhanced stability in aqueous phase containing 20 % dimethyl sulfoxide. The conversion of asymmetric amination on 50 g/L pro-sitagliptin ketone PTfpB (1-[1-piperidinyl]-4-[2,4,5-trifluorophenyl]-1,3-butanedione) achieved 92 %, with an extremely high e.e. of >99 %, using 2 gDCW/L E. coli cells harboring M1 + M122H as biocatalyst. In the kilogram-scale experiment, approximately 40 kg of (R)-APTfpB (e.e. >99 %) was produced within 30 h when 50 kg PTfpB was used as the substrate. Furthermore, the space-time yield reached ≈32 g/(L·d).

Fluorescence-based high-throughput screening system for R-ω-transaminase engineering and its substrate scope extension.

ω-Transaminase (ω-TA) is an attractive alternative to metal catalysts for the stereoselective amination of prochiral ketones. The narrow substrate scope of an R-ω-transaminase from Mycobacterium vanbaalenii (MvTA) limits its application in R-amine synthesis. A fluorescence-based TA activity screening system was developed to extend its substrate scope. The reactions were conducted in microtiter plates (MTPs) and displayed low background interference, high sensitivity (µM magnitude), and a wide dynamic range (ɀ-factor > 0.9). A KnowVolution campaign was performed on this enzyme, and screening ~ 8000 clones with this fluorescence-based screening system resulted in two beneficial substitutions (G68Y and F129A) and three improved variants (M3, M4, and M5). The best variant, MvTA M5 (WT+G68Y+F129A), achieved the highest catalytic efficiency (toward fluorogenic substrate NMA) which was 3.2-fold higher than that of the WT enzyme. MvTA M5 exhibited significantly enhanced activity toward six different prochiral ketones with e.e. > 99% (R). The specific activity of MvTA M5 was more than 100 times higher than that of the WT enzyme toward acetonaphthone (M5: 8.1 U/mg, WT: ~ 0.07 U/mg), and it showed the highest activity on acetonaphthone, p-ethylacetophenone, and phenylacetone.

Arthrobacter ruber sp. nov., isolated from glacier ice.

A Gram-stain-positive strain designated MDB1-42T was isolated from ice collected from Midui glacier in Tibet, PR China. Strain MDB1-42T was catalase-positive, oxidase-negative and grew optimally at 25-28 °C and pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that MDB1-42T represented a member of the genus Arthrobacter. The highest level of 16S rRNA gene sequence similarity (99.86 %) was found with Arthrobacter agilis NBRC 15319T. Multilocus sequence analysis revealed low similarity of 91.93 % between MDB1-42T and Arthrobacter agilis NBRC 15319T. Average nucleotide identity and digital DNA-DNA hybridization values between MDB1-42T and the most closely related strain, Arthrobacter agilis DSM 20550T, were 81.36 and 24.5 %, respectively. The genomic DNA G+C content was 69.0 mol%. The major cellular fatty acids of MDB1-42T were anteiso-C15 : 0 and anteiso-C17:0. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, one unidentified glycolipid and one unidentified lipid. The predominant menaquinone was MK-9(H2). On the basis of results obtained using a polyphasic approach, a novel species Arthrobacter ruber sp. nov. is proposed, with MDB1-42T (=CGMCC 1.9772T=NBRC 113088T) as the type strain.

Cryobacterium aureum sp. nov., a psychrophilic bacterium isolated from glacier ice collected from the ice tongue surface.

A psychrophilic, Gram-stain-positive, rod-shaped bacterium, designated strain Hh31T, was isolated from Xinjiang No. 1 Glacier in China. Strain Hh31T was catalase-positive, oxidase-negative and able to grow at between 0-18 °C. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Hh31T belonged to the genus Cryobacterium and was most closely related to the type strains of Cryobacterium levicorallinum, Cryobacterium luteum and Cryobacterium flavum. DNA-DNA hybridization, calculation of average nucleotide identity and digital DNA-DNA hybridization revealed that strain Hh31T was distinct from its closest phylogenetic neighbours. The major cellular fatty acids of strain Hh31T were anteiso-C15 : 0, anteiso-C15 : 1, iso-C15:0, iso-C16 : 0 and anteiso-C17 : 0. The predominant menaquinones of strain Hh31T were MK-9 and MK-10. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid, one unidentified glycolipid and another unidentified lipid. Physiological tests such as carbon source utilization, showed phenotypic differentiation of strain Hh31T from the closest related phylogenetic neighbours. Based on a polyphasic approach, a novel species, Cryobacterium aureum sp. nov., is proposed, with Hh31T (=NBRC 107882T=CGMCC 1.11213T) as the type strain.

Expression and Characteristics of an Endoglucanase from Trichoderma atroviride (TaEGII) in Saccharomyces cerevisiae.

Endoglucanase secreted by the fungus Trichoderma atroviride is a kind of cellulase. An endoglucanase gene egII was cloned from T. atroviride AS3.3013 and expressed in Saccharomyces cerevisiae INVScI. The open reading frame of the egII gene was composed of 1257 bp, encoding 418 amino acids with a molecular weight of 44.23 kDa plus a signal peptide of 21 amino acids. Based on sequence similarity, TaEGII belonged to the glycosyl hydrolase family 5. Expression of the egII gene in T. atroviride AS3.3013 can be induced by microcrystalline cellulose (MCC), bran, carboxymethyl cellulose (CMC), rice straw, and corn stalk but is inhibited by glucose. A highly efficient integrated expression vector (pYPIGH-B includes a sequence of the α-mating factor signal peptide (MF-α)) was constructed. The enzymatic activity of the supernatant of recombinant yeast YPIGH-B3 was 1.29 times higher than that of YES2-egII, demonstrating that the MF-α can significantly improve the expression of the recombinant EGII in S. cerevisiae. The recombinant endoglucanase TaEGII produced by S. cerevisiae showed maximum activity at pH 5.0 and temperature 60 °C. Under these conditions, the Km and Kcat values for Avicel and raffinose hydrolysis were 1.22 × 10-2 mg ml-1, 9.09 × 10-2 s-1 and 1.06 × 10-2 mg ml-1 , 9.18 × 10-2 s-1, respectively. The enzymatic activity of recombinant TaEGII was stable when incubated from 40 to 60 °C for 1 h. It was stable in a wide range of pH (4.0-7.0) and sensitive to various metal ions. Transgenic yeast strain YPIGH-B3 might be applied to cellulosic ethanol production.

Transcriptome Analysis of the Cf-12-Mediated Resistance Response to Cladosporium fulvum in Tomato.

Cf-12 is an effective gene for resisting tomato leaf mold disease caused by Cladosporium fulvum (C. fulvum). Unlike many other Cf genes such as Cf-2, Cf-4, Cf-5, and Cf-9, no physiological races of C. fulvum that are virulent to Cf-12 carrying plant lines have been identified. In order to better understand the molecular mechanism of Cf-12 gene resistance response, RNA-Seq was used to analyze the transcriptome changes at three different stages of C. fulvum infection (0, 4, and 8 days post infection [dpi]). A total of 9100 differentially expressed genes (DEGs) between 4 and 0 dpi, 8643 DEGs between 8 and 0 dpi and 2547 DEGs between 8 and 4 dpi were identified. In addition, we found that 736 DEGs shared among the above three groups, suggesting the presence of a common core of DEGs in response to C. fulvum infection. These DEGs were significantly enriched in defense-signaling pathways such as the calcium dependent protein kinases pathway and the jasmonic acid signaling pathway. Additionally, we found that many transcription factor genes were among the DEGs, indicating that transcription factors play an important role in C. fulvum defense response. Our study provides new insight on the molecular mechanism of Cf resistance to C. fulvum, especially the unique features of Cf-12 in responding to C. fulvum infection.

L-gulono-γ-lactone oxidase expression and vitamin C synthesis in the brain and kidney of the African lungfish, Protopterus annectens.

This study aimed to test the hypothesis that the brain of Protopterus annectens expressed L-gulono-γ-lactone oxidase (gulo/Gulo), the enzyme catalyzing the last step of ascorbate biosynthesis, and could maintain high concentrations of ascorbate during estivation. We cloned and sequenced gulo from the kidney of P. annectens and performed quantitative PCR to determine its mRNA expression in kidney and brain. Gulo activity was assayed and its protein abundance was determined by Western blot using custom-made anti-Gulo antibody. Effects of estivation on concentrations of ascorbate and dehydroascorbate in the kidney and brain were also determined. Both brain and kidney, but not liver, of P. annectens expressed gulo/Gulo. Desiccation induced P. annectens to estivate, and 6 mo of estivation led to drastic decreases in gulo/Gulo expression and ascorbate concentration in the kidney. However, high concentrations of ascorbate and ascorbate + dehydroascorbate were maintained in the brain during estivation, probably resulting from in situ ascorbate synthesis. Control fish were placed in freshwater, where they were fully active in a favorable environment unlike estivation on land. The ability to synthesize ascorbate to ameliorate oxidative stress directly in the brain might contribute to the ability of P. annectens to undergo prolonged estivation on land.

Preoperative lymphocyte count is a favorable prognostic factor of disease-free survival in non-small-cell lung cancer.

Recently, the prognostic value of cancer-related inflammatory response has been revealed. Previous studies showed that peripheral neutrophils and lymphocytes had significant impact on the prognosis of advanced and early-node-negative non-small-cell lung cancer (NSCLC). The purpose of this study was to investigate the prognostic value of preoperative lymphocyte and neutrophil counts in patients with NSCLC who underwent lobectomy and lymph node dissection and adjuvant chemotherapy. Retrospective analyses were performed to examine the impact of preoperative peripheral lymphocyte and neutrophil counts on disease-free survival (DFS) and overall survival (OS) and to analyze the relationships of these factors to clinicopathological factors. A total of 142 patients with NSCLC were evaluated of which 57 (40.1 %) patients had local recurrence or metastasis. Multivariate analyses revealed that peripheral lymphocyte count was an independent favorable prognostic factor of DFS (hazard ratio 0.548; 95 % confidence interval 0.351-0.857; P = 0.008) but not OS (P = 0.164). The maximum logrank statistical value was 9.504 (P = 0.002) when the cutoff value of lymphocyte was 1,800 mm(-3). The median DFS was 318.0 days (95 % confidence interval 226.0-410.0) for lymphocyte ≤1,800 mm(-3) group and 669.0 days (95 % confidence interval 0.0-1,431.0) for lymphocyte >1,800 mm(-3) group. Low lymphocyte count was related with lymphatic invasion (P = 0.012) and recurrence of NSCLC (P = 0.022). Peripheral neutrophil count had no impact on DFS or OS when analysis included all the 142 patients. Preoperative peripheral lymphocyte count, which is related with lymphatic invasion, is an independent favorable prognostic factor of DFS in patients with NSCLC who underwent lobectomy and lymph node dissection and adjuvant chemotherapy.

HIF-1α siRNA and cisplatin in combination suppress tumor growth in a nude mice model of esophageal squamous cell carcinoma.

INTRODUCTION: The esophagus squamous cell carcinoma (ESCC) is one of the most deadly malignances, and a current challenge is the development of effective therapeutic agents. Our present work addressed the effect of HIF-1α siRNA alone or in combination with cisplatin on the growth of ESCC in nude mice. MATERIALS AND METHODS: Xenografts were established by inoculating ESCC TE-1 cells in nude mice, and transplanted tumors were treated with HIF-1α siRNA, cisplatin alone or together. Growth was assessed by measuring tumor volume. HIF-1α mRNA and protein expression were detected using RT-PCR and immunohistochemistry, respectively. Apoptosis of ESCC TE-1 cells was analyzed by flow cytometry. RESULTS: In our nude mice model, HIF-1α siRNA effectively inhibited the growth of transplanted ESCC, downregulating HIF-1α mRNA and protein expression, and inducing ESCC TE-1 cell apoptosis. Notably when combinated with cisplatin, HIF-1α siRNA showed synergistic interaction in suppressing tumor growth. Furthermore, the proportion of apoptotic cells in HIF- 1α siRNA plus cisplatin group was significantly higher than that in cisplatin or HIF-1α siRNA-treated groups (P<0.05). CONCLUSIONS: Down-regulated HIF-1α expression induced by siRNA could effectively suppress the growth of transplanted ESCC in vivo. HIF-1α siRNA could enhance the cytotoxicity of cisplatin, which suggests that a combination of these two agents may have potential for therapy of advanced ESCC.

Disruption of a rice pentatricopeptide repeat protein causes a seedling-specific albino phenotype and its utilization to enhance seed purity in hybrid rice production.

The pentatricopeptide repeat (PPR) gene family represents one of the largest gene families in higher plants. Accumulating data suggest that PPR proteins play a central and broad role in modulating the expression of organellar genes in plants. Here we report a rice (Oryza sativa) mutant named young seedling albino (ysa) derived from the rice thermo/photoperiod-sensitive genic male-sterile line Pei'ai64S, which is a leading male-sterile line for commercial two-line hybrid rice production. The ysa mutant develops albino leaves before the three-leaf stage, but the mutant gradually turns green and recovers to normal green at the six-leaf stage. Further investigation showed that the change in leaf color in ysa mutant is associated with changes in chlorophyll content and chloroplast development. Map-based cloning revealed that YSA encodes a PPR protein with 16 tandem PPR motifs. YSA is highly expressed in young leaves and stems, and its expression level is regulated by light. We showed that the ysa mutation has no apparent negative effects on several important agronomic traits, such as fertility, stigma extrusion rate, selfed seed-setting rate, hybrid seed-setting rate, and yield heterosis under normal growth conditions. We further demonstrated that ysa can be used as an early marker for efficient identification and elimination of false hybrids in commercial hybrid rice production, resulting in yield increases by up to approximately 537 kg ha(-1).

[Current status and industrialization of transgenic tomatoes].

In this review, the progress in transgenic tomato research, including disease and insect resistance, herbicide resistance, stress tolerance, long-term storage, quality improvement, and male sterility, were described. The recent researches on producing heterologous proteins using transgenic tomatoes were also reviewed. Furthermore, the industrialization status and problems of transgenic tomatoes were analyzed and the prospects of both research and industrialization in transgenic tomatoes were discussed.

[Effects of exogenous nitric oxide on active oxygen metabolism and photosynthetic characteristics of tomato seedlings under cadmium stress].

A hydroponic experiment was conducted to study the effects of exogenous sodium nitroprusside (SNP), a NO donor, on the active oxygen metabolism and photosynthetic characteristics of tomato (Lycopersicon esculentum Mill.) seedlings under Cd stress. The results showed that under the stress, applying 100 micromol x L(-1) SNP promoted the activities of plant superoxide dismutase (SOD) and catalase (CAT) significantly, increased the leaf- and root calcium (Ca) and iron (Fe) contents and the leaf chlorophyll content, net photosynthetic rate (P(n)), transpiration rate (T(r)), and stomatal conductance (G(s)), and decreased the contents of H2O2 and MDA and the concentration of intercellular CO2 (C(i)). The addition of hemoglobin, a NO scavenger, eliminated the effects of SNP, while applying 100 micromol x L(-1) sodium nitrate or nitrite (the decomposition products of NO or its donor SNP) or 100 micromol x L(-1) sodium ferrocyanide (an analog of SNP) had no significant alleviation effects on Cd stress. This study suggested that exogenous NO could promote the scavenging of reactive oxygen, keep the mineral nutrition in balance, and alleviate the damage of Cd stress to the leaf photosynthetic apparatus, making the tomato seedlings preserve their photosynthetic efficiency.

Malnutrition and inflammation in acute kidney injury due to earthquake-related crush syndrome.

BACKGROUND: Malnutrition and inflammation are common and serious complications in patients with acute kidney injury (AKI). However, the profile of these complications in patients with AKI caused by crush syndrome (CS) remains unclear. This study describes the clinical characteristics of malnutrition and inflammation in patients with AKI and CS due to the Wenchuan earthquake. METHODS: One thousand and twelve victims and eighteen healthy adults were recruited to the study. They were divided into five groups: Group A was composed of victims without CS and AKI (904 cases); Group B was composed of patients with CS and AKI who haven't received renal replacement therapy (RRT) (57 cases); and Group C was composed of patients with CS and AKI receiving RRT (25 cases); Group D was composed of earthquake victims with AKI but without CS (26 cases); and Group E was composed of 18 healthy adult controls. The C-reactive protein (CRP), prealbumin, transferrin, interleukin-6 and TNF-alpha were measured and compared between Group E and 18 patients from Group C. RESULTS: The results indicate that participants in Group C had the highest level of serum creatinine, blood urea nitrogen and uric acid. Approximately 92% of patients with CS who had RRT were suffering from hypoalbuminemia. The interleukin-6 and CRP levels were significantly higher in patients with CS AKI receiving RRT than in the control group. Patients in Group C received the highest dosages of albumin, plasma or red blood cell transfusions. One patient in Group C died during treatment. CONCLUSIONS: Malnutrition and inflammation was common in patients with earthquake-related CS and had a negative impact on the prognosis of these subjects. The results of this study indicate that the use of RRT, intensive nutritional supplementation and transfusion alleviated the degree of malnutrition and inflammation in hemodialysis patients with crush syndrome.

Cloning and heterologous expression of a novel endoglucanase gene egVIII from Trichoderma viride in Saccharomyces cerevisiae.

Endoglucanase is a major cellulolytic enzyme produced by the fungus Trichoderma viride. The 1,317 bp cDNA of endoglucanase gene egVIII was cloned from T. viride AS3.3711, encoding a 438 amino acid protein with a calculated molecular mass of 46.86 kDa and isoelectric point of 4.32. Sequence analysis suggested that EGVIII belonged to the glycosyl hydrolase family 5. The N-terminal region of EGVIII contains a signal peptide sequence of 19 amino acid residues, indicating that it is an extracellular enzyme. Transcription of the egVIII gene in T. viride AS3.3711 can be induced by carboxymethyl cellulose sodium (CMC-Na), sucrose, microcrystalline cellulose, and corn stalk, and inhibited by glucose and fructose. The alpha-mating factor signal can effectively enhance the secretion of the recombinant EGVIII in Saccharomyces cerevisiae, as demonstrated by the enzymatic activity of recombinant yeast IpYEMalpha-xegVIII in the supernatant, which was 0.86 times higher than that of the IpYES2-egVIII. Recombinant endoglucanase EGVIII showed optimal activity at a temperature of 60 degrees C and pH of 6.0. It was stable when incubated from 35 degrees C to 70 degrees C for 1 h. The enzymatic activity of recombinant EGVIII was stable at a pH 3.0 to 7.5 at 50 degrees C and reached the highest level at 0.174U when activated by 75 mM of Zn(2+). The Michaelis-Menten constant (Km) and Kcat values for CMC-Na and cellotriose hydrolysis were 3.82 mg/ml, 9.56 s(-1) and 1.75 mg/ml, 7.08 s(-1), respectively. Transgenic yeast strain IpYEMalpha-xegVIII might be useful for renewable fuels industries.

[Inhibition of bladder cancer cell growth and angiogenesis by co-blockage of vascular endothelial growth factor and its receptor KDR].

OBJECTIVE: To study the effect of co-blockage of vascular endothelial growth factor (VEGF) and its receptor (KDR) on growth of bladder carcinoma T24 cells and nude mice xenograft. METHODS: T24 cell line co-transfected with VEGF siRNA and sKDR expression plasmids was developed and its proliferation was assayed by MTT and apoptosis by FCM. The nude mice model bearing bladder carcinoma xenograft was established. The tumor cell VEGF expression, stroma microvessel density (MVD) and tumor cell topoisomerase II alpha (Topo II alpha) expression were detected by immunohistochemistry. Cell apoptosis was estimated by TUNEL assay. RESULTS: MTT assay showed that cell proliferation in VEGF siRNA, sKDR and combination groups was 56.3% +/- 8.3%, 42.6% +/- 13.8% and 32.5% +/- 4.3%, respectively, significantly lower than that in the scramble control (97.3% +/- 11.6%, P < 0.0001). FCM showed there were sub-diploid apoptotic peaks before G1 phase in VEGF siRNA, sKDR and combination groups, and apoptosis ratio was 5.1% +/- 0.9%, 4.2% +/- 0.5% and 8.8% +/- 0.7%, respectively, all of which were higher than that in the scramble control (0.9% +/- 0.4%, P < 0.05), and the combination group had even more higher apoptosis than the two singlely treated groups (P < 0.01). In vivo test showed that tumor growth was inhibited in VEGF siRNA, sKDR and combination groups, and from day 16 the tumor volume in combination group was significantly smaller than that in scramble control (P < 0.05), and from day 28 the tumor almost lost the ability to further growth. Immunohistochemistry revealed VEGF expression in combination group was 54.37 +/- 5.28, significantly lower than that in the scramble control (141.66 +/- 8.59, P < 0.0001). MVD number was only 8.22 +/- 3.79, much less compared with that in the scramble control (61.76 +/- 5.28, P < 0.0001) or sKDR group (19.46 +/- 4.16, P = 0.0089). Tumor cell proliferation index in the combination group (1.5% +/- 0.7%) was significantly decreased compared with that in the scramble control (11.8% +/- 5.2%, P < 0.0001), and apoptosis index (67.2% +/- 8.5%) was much higher than that in the scramble control (8.7% +/- 2.7%, P < 0.0001), VEGF siRNA group (54.3% +/- 4.8%, P = 0.0492) or sKDR group (52.3% +/- 6.4%, P = 0.0293). CONCLUSION: VEGF siRNA or sKDR alone can inhibit tumor cell proliferation and induce cell apoptosis, but co-blockage of VEGF and KDR by their combination shows more significant therapeutic efficacy.

Photoconductive method for measuring light transmission to the root of metal-ceramic and all-ceramic restorations.

OBJECTIVES: In this study, the authors attempted to develop a photoconductive method for measuring light transmission through a crown restoration to the root dentin; metal-ceramic crowns with four coping designs (metal collar, and metal framework ending 0, 1, and 2mm coronal to the axiogingival line angle) and two all-ceramic crowns (Empress II and In-Ceram Alumina) were compared. METHODS: According to pre-registered templates, 36 crowns were fabricated for an extracted central incisor. A cadmium sulfide (CdS) photoconductive cell was secured onto the root of a tooth, which was fixed in a light box. The validity and reliability of the experimental design were verified, and the impedance of the cell was recorded when the crowns were placed on the prepared tooth with or without try-in pastes under a constant luminance. RESULTS: A significant correlation (r= -0.99, p<0.001) was found between the light intensity and impedance of the CdS cell, and a 1.15% coefficient of variation between repeated measurements was observed. In this study, Empress II crowns had the smallest impedance, indicating that they provided the best light transmission. Conventional metal-ceramic crowns had the least light transmission, which was significantly improved by reducing the metal collar (p<0.05). The framework of metal-ceramic crowns which ended 2mm coronal to the axiogingival line angle showed as much light transmission as the In-Ceram crowns. The impedance increased when try-in pastes were employed in all test groups. SIGNIFICANCE: The photoconductive method was proven to be a reliable technique for measuring the light transmitted through restorations into the adjacent tissue.

[Nuclear and cytoplasmic genome analysis of somatic hybrid of Triticum aestivum L. and Leymus chinensis (Trin.) Tzvel].

Intergeneric somatic hybrids were obtained by fusion between protoplasts of Triticum aestivum L. cv. Jinan 177 and Leymus chinensis (Trin.) Tzvel. Protoplasts of L. chinensis were exposed to UV (300 microW/cm(2)) for 30 s, 45 s and 1 min before fusion. The results of morphological and chromosomal observation, isozyme pattern as well as RAPD analysis and the 5S rDNA space sequence analysis showed the hybrid nature of the regenerated colonies of fusion combination T (+) L (UV 30 s). Restriction Fragment Length Po1ymorphism (RFLP) analysis using mitochondrion-specific atp6 and chloroplast-specific rbcL probes showed that most of the organelle genomes of the hybrids originated from L. chinensis and some recombination happened between wheat and L. chinensis. The effects of elimination of the nuclear genome of receptor protoplast on hybrid regeneration and receptor organelle genome elimination are discussed.