Deficiency of plasminogen receptor, Plg-RKT , causes defects in plasminogen binding and inflammatory macrophage recruitment in vivo

Essentials Plg-RKT is a novel integral membrane plasminogen receptor. The functions of Plg-RKT in vivo are not known. Plg-RKT is a key player in macrophage recruitment in the inflammatory response in vivo. Plg-RKT deficiency is not compatible with survival of the species.

SUMMARY

Background Plg-RKT is a novel integral membrane plasminogen receptor that binds plasminogen via a C-terminal lysine exposed on the cell surface and promotes plasminogen activation on the cell surface by both tissue plasminogen activator and urokinase plasminogen activator. Objectives To evaluate the role of Plg-RKT in vivo we generated Plg-RKT-/- mice using a homologous recombination technique. Methods We characterized the effect of Plg-RKT deletion on reproduction, viability, health and spontaneous thrombosis and inflammation. Results Plg-RKT-/- mice were viable and fertile. Survival of Plg-RKT-/- mice and Plg-RKT+/+ littermates was not significantly different. However, quite strikingly, all pups of Plg-RKT-/- females died within 2 days of birth, consistent with a lactation defect in Plg-RKT-/- mothers. Additionally, there was a significant effect of Plg-RKT deficiency on the growth rates of female, but not male, mice. In experimental peritonitis studies, Plg-RKT-/- mice exhibited a marked defect in macrophage recruitment. As a contributing mechanism, the capacity of Plg-RKT-/- macrophages for plasminogen binding was markedly decreased. Conclusions These studies demonstrate that Plg-RKT is required for plasminogen binding and macrophage migration in vivo. In addition, Plg-RKT deficiency is not compatible with survival of the species, due to the death of all offspring of Plg-RKT-/- females. This new mouse model will be important for future studies aimed at delineating the role of cell surface plasminogen activation in challenge and disease models in vivo.

[Telbivudine for prevention of perinatal transmission in pregnant women infected with hepatitis B virus in immune-tolerant phase: a study of efficacy and safety of drug withdrawal]

OBJECTIVE

To observe the success rate of telbivudine (LdT) for the prevention of perinatal transmission of hepatitis B virus (HBV) and the incidence of alanine aminotransferase (ALT) elevation during LdT treatment and after LdT withdrawal in HBV-infected pregnant woman with high viremia in immune-tolerant phase and receiving LdT treatment at the end of pregnancy, and to evaluate the efficacy of LdT in the prevention of perinatal transmission and the safety for pregnant women.

METHODS

Pregnant women infected with HBV in immune-tolerant phase who had normal ALT levels (≤40 U/L) and high viremia (HBV DNA ≥6 log10 IU/ml) with positive HBeAg were enrolled as subjects. All pregnant women received antiviral treatment with LdT at the end of pregnancy to prevent perinatal transmission of HBV. All infants received standard combined immunoprophylaxis. Failure for prevention of perinatal transmission of HBV was defined as positive HBsAg or HBV DNA in infants 7 months of age (or at one month after the third injection of hepatitis B vaccine). Liver function, HBV DNA, and HBV serological markers were evaluated at baseline, after 1 month of treatment, before childbirth, and 1, 3, and 6 months after drug withdrawal. SPSS 16.0 software was used to analyze the data. Between-group comparison of continuous data was made by t test, and comparison of categorical data was made by chi-square test.

RESULTS

One hundred and four pregnant women (treatment group) received oral administration of 600 mg LdT once a day, and 25 pregnant women (observation group) did not receive any antiviral therapy. The success rate for the prevention of perinatal transmission was significantly higher in the treatment group than in the observation group (100% vs 89.47%, χ (2) = 9.862, P = 0.028). There was no significant difference in the incidence of ALT elevation during treatment and within 6 months after drug withdrawal between the treatment group and the observation group (4.81% (5/104) vs 4.00% (1/25), χ (2) = 0.030, P = 1.000). In the treatment group, the mean HBV DNA at baseline was significantly higher than that before childbirth (8.20±0.78 vs 3.98±0.90 log10IU/ml, t = 6.979, P < 0.001). One hundred patients with drug withdrawal had HBV DNA increased to 8.11±0.80 log10 IU/ml at one month after childbirth.

CONCLUSION

LdT treatment at the end of pregnancy can effectively reduce the incidence of perinatal transmission of HBV in pregnant women with high viremia in immune-tolerant phase. The immediate drug withdrawal after childbirth is safe for the mother. The incidence of hepatitis is low after drug withdrawal.

A transcriptional cofactor YAP regulates IFNT expression via transcription factor TEAD in bovine conceptuses

Interferon tau (IFNT) is the pregnancy recognition protein in all ruminants, and its expression is restricted to trophoblast cells. Interferon tau production increases as the conceptus elongates; however, its expression is downregulated soon after the initiation of conceptus attachment to the uterine epithelium. Our previous study identified that among 8 bovine IFNT genes, only 2 forms of IFNTs, IFNT2 and IFN-tau-c1, were expressed by the conceptuses during the periattachment period. To characterize whether Hippo signaling including a transcription cofactor yes-associated protein (YAP) was involved in the IFNT regulation, we examined the expression and effects of YAP and/or TEAD in human choriocarcinoma JEG3 and bovine trophoblast CT-1 cells, and in bovine conceptuses obtained from day 17, 20 or 22 pregnant animals (pregnant day 19.5 = day of conceptus attachment to the endometrium). YAP was expressed in bovine conceptuses and transfection of YAP or TEAD4, a transcription factor partner of YAP, expression plasmid increased the luciferase activity of IFNT2 and IFN-tau-c1 reporter plasmids in JEG3 cells. In the presence of YAP expression plasmid, TEAD2 or TEAD4 expression plasmid further upregulated transcriptional activity of IFNT2 or IFN-tau-c1 constructs, which were substantially reduced in the absence of the TEAD-binding site on IFNT2 or IFN-tau-c1 promoter region in JEG3 cells. In CT-1 cells, treatment with TEAD2, TEAD4, or YAP small-interfering RNA downregulated endogenous IFNT expression. It should be noted that TEAD2 and TEAD4 were predominantly localized in the nuclei of trophectoderm of Day 17 conceptuses, but nuclear localization appeared to be lower in those cells of conceptuses on days 20 and 22 of pregnancy. Moreover, the binding of TEAD4 to the TEAD-binding site of the IFN-tau-c1 promoter region in day 17 conceptuses was less in day 20 and 22 conceptuses. Furthermore, the level of YAP phosphorylation increased in day 20 and 22 conceptuses. These results indicated that although YAP/TEAD had the ability to up-regulate IFNT gene transcription on day 17, IFNT2 or IFN-tau-c1 was down-regulated following changes in the localization of TEAD2 and TEAD4 from the nucleus to the cytoplasm and increases in phosphorylation and degradation of YAP. These data suggest that TEAD relocation and/or YAP degradation following its phosphorylation down-regulates IFNT gene transcription after conceptus attachment to the uterine endometrium.

[An experimental study of mesenchymal stem cells in tissue engineering scaffolds implanted in rabbit corneal lamellae to increase keratoprosthesis biointegration]

OBJECTIVE

To complete a preliminary evaluation of the feasibility of implanting the complex of mouse bone marrow mesenchymal stem cells (BMSC) and a tissue engineering scaffold into rabbit corneal lamellae, based on which a solution may be proposed to consolidate the keratoprosthesis and the recipient surface, and to reduce the risk of complications.

METHODS

This experimental study was composed of two parts. (1) In vitro: some mouse BMSC were marked with red fluorescent proteins (RFP) and integrated with a decellularized pig articular cartilage extracellular matrix (ECM) scaffold. The cell survival was observed under a fluorescence microscope at 4 and 8 weeks. The cell distribution was examined by toluidine blue staining. The pore structure and the cell adhesion were observed under a scanning electron microscope. (2) in vivo: the complex of mouse BMSC and a decellularized scaffold was implanted into the lamellar cornea of 8 rabbit eyes with the fellow eyes as the controls. The eyes were sampled for observation using HE staining under a light microscope at 2, 4 and 8 weeks, respectively. The cell survival was examined under a fluorescence microscope, and the intracorneal cell survival at 8 weeks was observed using in vivo imaging. The conditions of ocular anterior segment of all the experimental animals were recorded.

RESULTS

(1) Under the scanning electron microscope, the ECM scaffolds showed satisfactory porosity required for the adhesion and growth of cells and tissues, and the cell distribution over the cell-scaffold complex can be observed by toluidine blue staining. (2) Under the immunofluorescence microscope, cell proliferation was observed in vitro and in the interlamellar space (the maximum observation time was 8 weeks) after the RFP-marked mouse BMSC were integrated in vitro with ECM scaffolds. (3) Under the light microscope (HE staining), the stromal cells were detected to increase at each timepoint. A small number of monocytes and some mouse BMSC were observed in the superficial layer of corneal stroma, with sparsely and orderly arranged collagenous fibers and no neovascularization. All the epithelial cells appeared as mononuclear, columnar and undamaged, and the shape of ECM scaffolds, which were fused with the collagens, became unclear. (4) By in vivo imaging, it was found that the mouse BMSC survived for 8 weeks after being integrated with scaffolds and implanted into the interlamellar space of rabbit cornea. (5) After the implantation of cell-scaffold complex, severe postoperative inflammatory reactions, obvious conjunctival congestion and neovascularization were not observed. The corneal tissues surrounding the recipient area were transparent. One week later, mild inflammatory reactions were barely observed, and the cornea was transparent enough to observe the scaffold in the stromal layers. Four weeks later, the scaffolds became thinner. Eight weeks later, the scaffolds became extremely thin with normal vascular system in the corneal limbus.

CONCLUSIONS

The ECM scaffold is a solid and biocompatible carrier for the growth and proliferation of BMSC. The mouse BMSC can grow and proliferate in the microenvironment of the interlamellar space of cornea.

Real-time PCR assay with high resolution melting for EGFR and BIM mutation of lung cancer

OBJECTIVE

To establish and develop a reliable and simple Real-time PCR assay with high resolution melting (Real-time PCR-HRM) method for detection epidermal growth factor (EGFR) and BIM mutation of lung cancer and looking for effective targeted drugs to control lung cancer.

PATIENTS AND METHODS

A total of 6858 participants (2538 cases with lung cancer and 4275 healthy controls who took part in the study by doing the physical examination in Shanghai Xuhui community) were recruited in the study. Clinical characteristics and 5 ml peripheral blood were collected from each participant, and the DNA has been extracted, which were determined the EGFR and BIM mutation by Real-time PCR-HRM. Data were recorded and Statistical analyses.

RESULTS

All samples completed the study. BIM deletion polymorphism was no related with age, sex, and smoking or EGFR mutation.

CONCLUSIONS

There were no relations among BIM deletion polymorphism, EGFR mutation or lung cancer risk. HRM is a novel procedure and provides rapid, sensitive, specific and simultaneous detection for gene mutation of cancer patients for predicting the efficacy of targeted therapy.

Molecular cloning and expression analysis of Fem1b from oriental river prawn Macrobrachium nipponense

Feminization-1 homolog b (Fem1b) is one of the genes essential for male development and play central roles in sex determination of Caenorhabditis elegans. In this study, we cloned and characterized the full-length Fem1b cDNA from the freshwater prawn Macrobrachium nipponense (MnFem1b) in different tissues and at different developmental stages. Real-time quantitative reverse polymerase chain reaction (RT-qPCR) showed that the MnFem1b gene was expressed in all investigated tissues, with the highest expression level found in the testes. The results revealed that the MnFem1b gene might play roles in aspects of development of the male prawn phenotype. The RT-qPCR also revealed that MnFem1b mRNA expression was significantly increased at 10 days after metamorphosis. The expression levels in all investigated tissues showed a certain degree of sexually dimorphism, the expression levels in males were significantly higher than those in females (P < 0.05). Notably, the highest expression of MnFem1b was found in the testes. The expression of MnFem1b in different tissues indicates that it plays multiple biological functions in M. nipponense.

Association between the pre-miR-196a2 rs11614913 polymorphism and gastric cancer susceptibility in a Chinese population

We did a case-control study to provide a more comprehensive evaluation of the association of the pre-miR-196a2 rs11614913 polymorphism with gastric cancer. Between January 2013 and December 2014, 182 patients newly diagnosed with primary gastric cancer and 182 control subjects were recruited at Zhengzhou People's Hospital. For SNP genotyping, we used the Assay Designer 3.1 to design the primers of polymerase chain reaction. Using the chi-square test, we found that patients with gastric cancer were more likely to be alcohol drinkers (χ(2) = 4.4, P = 0.04), to have a family history of cancer in the first relatives (χ(2) = 5.29, P = 0.02), and to be infected with Helicobacter pylori (χ(2) = 23.39, P < 0.001). A significant difference in the genotype distributions of rs11614913 was observed in our study (χ(2) = 6.66, P = 0.04). By logistic regression analysis, we found that the CC genotype of rs11614913 was associated with an increased risk of gastric cancer in a codominant model (OR = 2.68, 95%CI = 1.17-6.44). By stratification analysis, we found that the CC genotype was associated with a strongly increased risk of gastric cancer in drinkers when compared with the TT+TC genotype (OR = 5.63, 95%CI = 1.54-30.76). In conclusion, the results of our study suggest an association between the rs11614913 gene polymorphism and an elevated risk of gastric cancer, especially in drinkers.

Malignant pleural effusion cell blocks are substitutes for tissue in EML4-ALK rearrangement detection in patients with advanced non-small-cell lung cancer

OBJECTIVE

To evaluate the feasibility of malignant pleural effusions (MPE) as surrogate samples for the detection of echinoderm microtubule-associated protein-like4 (EML4)-anaplastic lymphoma kinase (ALK) and to investigate the prognostic and predictive value of EML4-ALK in MPE of non-small-cell lung cancer (NSCLC).

METHODS

One hundred and nine NSCLC patients were retrospectively analysed. EML4-ALK was identified using paraffin-embedded tumour cells in MPE samples by immunohistochemistry (IHC, Ventana) and confirmed by fluorescence using in situ hybridisation (FISH) and qRT-PCR. The EGFR mutation was determined by MPE, using denaturing high-performance liquid chromatography (DHPLC).

RESULTS

A total of 5 out of 109 (4.58%) patients were identified as EML4-ALK rearrangement in MPE by IHC.; In addition to two metachronous samples, the consistency of MPE and tissue for EML4-ALK detection was 100% (21/21), and the sensitivity and specificity were 100% (2/2) and 100% (19/19), respectively. EML4-ALK rearrangement cases were confirmed by FISH and qRT-PCR; the sensitivity were both 100% (2/2) when compared with tissue, and it was 60% (3/5) and 100% (5/5), respectively, when compared with MPE by IHC. The overall response rate (ORR) was 100% (2/2) for patients with EML4-ALK in MPE. Moreover, the PFS of these patients appeared to be prolonged in chemotherapy (9.27 versus 6.53 and versus 4.67 months, P = 0.122), compared with the EGFR mutation and the EGFR/ALK double negative group, respectively.

CONCLUSION

EML4-ALK rearrangement detection in malignant pleural effusions is a complementary method for EML4-ALK detection. VETANA and qRT-PCR are more appropriate for MPE detection. EML4-ALK rearrangement in pleural effusions has a predictive value for treatment.

Association between ERCC5 gene polymorphisms and gastric cancer risk in a Chinese population

We conducted a hospital-based case-control study to investigate the association between 3 common SNPs in the ERCC5 gene (rs1047768, rs751402, and rs17655) and the risk of developing gastric cancer. Between January 2013 and December 2014, samples were collected from 216 gastric cancer patients and 216 control subjects. ERCC5 rs1047768, rs751402, and rs17655 polymorphisms were genotyped by polymerase chain reaction combined with restriction fragment length polymorphism analysis. By conditional logistic regression analysis, the GG genotype of rs17655 was found to be associated with an elevated risk of gastric cancer in a codominant model, and the adjusted OR (95%CI) was 1.96 (1.10-3.50). Moreover, in a dominant model, the CG + GG genotype of rs17655 was correlated with an increased risk of gastric cancer compared to the CC genotype (OR = 1.48; 95%CI = 1.00-2.22). rs1047768 and rs751402 were not significantly correlated with an increased or decreased gastric cancer risk.

Effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs

The experiment was conducted to investigate the effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs. One hundred eighty crossbred barrows (Landrace × Yorkshire, 60 ± 2.5 kg) were randomly allotted to 5 dietary treatments (36 pigs/treatment) and fed a basal diet supplemented with 0, 0.2%, 0.4%, 0.6%, and 0.8% fulvic acid for 42 d. Thirty pigs (6 pigs/treatment) were slaughtered at the end of the experiment. Blood samples and adipose tissue were collected for determination of blood parameters and lipid metabolic enzymes. The results showed that compared with the control group, dietary supplementation of 0.2%, 0.4%, and 0.6% fulvic acid significantly reduced mean backfat thickness of pigs (P < 0.05). The serum concentrations of low-density lipoprotein, leptin, growth hormone, insulin, and triiodothyronine were significantly increased by adding fulvic acid in diets (P < 0.05). With the raised concentration of dietary fulvic acid, hormone sensitive lipase (HSL) activity was significantly increased (P < 0.05), and lipoprotein lipase (LPL) activity was significantly decreased (P < 0.05) in adipose tissue. In conclusion, dietary supplementation of fulvic acid reduced the mean backfat thickness of pigs. This change related to the increased activity of HSL and the decreased activity of LPL in adipose tissue.

Autophagy in drug resistance of the multiple myeloma cell line RPMI8226 to doxorubicin

We investigated the effect of autophagy on drug resistance of multiple myeloma (MM) to doxorubicin (DOX). A DOX-resistant MM cell line (RPMI8226/DOX) was developed by progressively increasing the DOX concentration gradient. The drug resistance index was determined using the MTT method. Transmission electron microscopy, anti-light chain 3-fluorescein isothiocyanate immunofluorescence, and Western blotting were used to detect autophagy of MM cells. Flow cytometry was applied to detect changes in apoptosis of RPMI8226/DOX cells (stained with annexin-V/propidium iodide) caused by inhibition by hydroxychloroquine and 3-methyladenine on autophagy. The drug resistance index of RPMI8226/DOX to DOX was 10.8, and autophagy/lysosomal was clearly observed in RPMI8226/DOX cells under transmission electron microscopy, while immunofluorescence showed granular immunofluorescence in cells. Western blot analysis showed that light chain 3-II protein expression level was higher in RPMI8226/DOX cells than in RPMI8226/S cells. The apoptosis test showed that hydroxychloroquine or 3-methyladenine partially reversed the drug resistance of RPMI8226/DOX cells by inhibiting autophagy. Activation of autophagy in MM cells may explain the drug resistance of myeloma.

MKL1 potentiates lung cancer cell migration and invasion by epigenetically activating MMP9 transcription

Malignant tumors are exemplified by excessive proliferation and aggressive migration/invasion contributing to increased mortality of cancer patients. Matrix metalloproteinase 9 (MMP9) expression is positively correlated with lung cancer malignancy. The mechanism underlying an elevated MMP9 expression is not clearly defined. We demonstrate here that the transcriptional modulator megakaryocytic leukemia 1 (MKL1) was activated by hypoxia and transforming growth factor (TGF-β), two prominent pro-malignancy factors, in cultured lung cancer cells. MKL1 levels were also increased in more invasive types of lung cancer in humans. Depletion of MKL1 in lung cancer cells attenuated migration and invasion both in vitro and in vivo. Overexpression of MKL1 potentiated the induction of MMP9 transcription by hypoxia and TGF-β, whereas MKL1 silencing diminished MMP9 expression. Of interest, MKL1 knockdown eliminated histone H3K4 methylation surrounding the MMP9 promoter. Further analyses revealed that MKL1 recruited ASH2, a component of the H3K4 methyltransferase complex, to activate MMP9 transcription. Depletion of ASH2 ameliorated cancer cell migration and invasion in an MMP9-dependent manner. Together our data indicate that MKL1 potentiates lung cancer cell migration and invasion by epigenetically activating MMP9 transcription.

Folic acid supplementation and dietary folate intake, and risk of preeclampsia

BACKGROUND/OBJECTIVES

Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia.

SUBJECTS/METHODS

A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10,041 pregnant women without chronic hypertension or gestational hypertension were enrolled.

RESULTS

Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43-0.87). A significant dose-response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30-0.81) and late-onset (OR=0.60, 95% CI: 0.42-0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31-0.87, for the highest quartile of dietary folate intake compared with the lowest).

CONCLUSIONS

Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.

First Report of Foxtail Millet Seedling Damping-Off Caused by Binucleate Rhizoctonia AG-A in China

Foxtail millet (Setaria italica) is an important food and fodder grain crop in China. In June 2013, foxtail millet seedlings of cultivar Jigu19 showing symptoms of damping-off were observed with about 30% incidence in Handan, Hebei Province. Infected plants showed pale brown lesions on the stems and brown discoloration of the roots, which later turned into root rot. As a consequence, infected seedlings wilted and died prematurely. Segments of the diseased root tissue (5 mm long) were washed with sterile water, disinfected with 0.5% NaOCl for 2 min, rinsed with sterile water, placed on potato dextrose agar (PDA), and incubated at 25°C in the dark. Three isolates were obtained and designated HD-1, HD-3, and HD-5. Morphological characteristics of the three isolates were similar with white colonies bearing large amounts of floccose aerial hyphae and no production of sclerotia after 14 days. Hyphal cells were stained with DAPI and all the three isolates were binucleate. Total genomic DNA was extracted from the mycelial mat using CTAB (4). The rDNA internal transcribed spacer (ITS) region was amplified using the universal primer pair ITS1 and ITS4 (1). PCR amplicons were purified and sequenced. A BLASTn search revealed that the resulting sequences (GenBank Accession Nos. KM017960, KM017961, and KM017962 for HD-1, HD-3, and HD-5, respectively) shared 99% identity with other Ceratobasidium sp. AG-A isolates (JX913824, FJ440197). In addition, sequence identity of HD-1, HD-3, and HD-5 with each other was 99.8%, 99.7%, and 99.8%, respectively. Thus, the isolates were identified as Ceratobasidium sp. AG-A, i.e., binucleate Rhizoctonia (BNR) AG-A. Pathogenicity tests were conducted by placing autoclaved wheat seeds, each colonized with Rhizoctonia isolates at inoculum density of 25 propagules per gram (ppg), on the surface of a sterilized mix of soil, sand, and nutrient soil (1:1:1, v/v/v) in pots (3). Each pot contained five healthy seedlings of the foxtail millet cultivar Yugu 1, and every seedling was inoculated by placing three colonized wheat seeds under the sheath of foxtail millet at the 2- or 3-leaf stage; non-inoculated sterilized wheat seeds were used as a control. Plants were incubated at 25°C with 14 h light and 10 h dark in a growth room for 10 days, and then assessed for disease. Damping-off symptoms similar to those in the field appeared on inoculated plants; control plants were asymptomatic. BNR Rhizoctonia were re-isolated from diseased plants and confirmed to be AG-A based on morphological characteristics and rDNA-ITS sequence. BNR AG-A has been reported in China as a pathogen of Chinese mustard, Chinese cabbage, potato, and sugar beet, but there are no previous reports of its presence on foxtail millet. R. solani AG-1 and AG-4 are usually regarded as pathogenic to foxtail millet (2). To our knowledge, this is the first report of BNR AG-A causing foxtail millet damping-off in China. We found binucleate Rhizoctonia AG-A, the anamorph of Ceratobasidium sp., can infect foxtail millet at seeding stage, which may cause serious losses of the crop. Therefore, we should pay particular attention to it when considering seeding disease control and breeding disease resistance varieties of foxtail millet in the future. References: (1) K. de la Cerda et al. Plant Dis. 91:791, 2007. (2) W. D. Gao. Acta Phytopathologica Sinica. 17:247, 1987. (3) M. J. Lehtonen et al. Plant Pathol. 57:141, 2008. (4) M. G. Murray and W. F Thompson. Nucleic Acids Res. 8:4321, 1980.

First Report of Sheath Blight Caused by Waitea circinata Affecting Foxtail Millet (Setaria italica) in China

Foxtail millet (Setaria italica) is planted widely in northern China, especially in Hebei, Shanxi, Shandong, and Henan provinces. Although several diseases reduce production of this important crop species, sheath blight is considered one of the important diseases of foxtail millet in China. Sheath blight is caused by a soil-borne pathogen and is difficult to control. Epidemics are most common at the late growth stage of foxtail millet. In August 2013, an outbreak was recorded in Shijiazhuang city, Hebei, with an incidence of about 60%. Typical disease symptoms consisted of large, irregular lesions with reddish-brown margin and as the disease progressed, the plants lodge. Three representative sheath fragments (each 1 cm long) were collected from diseased plants during that outbreak. The samples were disinfected with 0.5% (v/v) sodium hypochlorite, rinsed with sterile water, placed on a water agar plate, and then incubated at 26°C in the dark for two days. After the hyphae appeared, ~3-mm-long hyphal tips from typical colonies were excised and transferred to potato dextrose agar (PDA) plates. Three isolates were obtained and all showed typical features of Rhizoctonia-like fungus. Each isolate occupied its whole plate within 5 days of incubation at 26°C in the dark, and abundant aerial mycelia were produced. The color of all colonies was first orange, turning a salmon color when the mycelia matured. Orange sclerotia appeared after 2 weeks of incubation. The nuclei were stained with DAPI (2-(4-amidinophenyl)-1H-indole-6-carboxamidine) and observed under a fluorescent microscope. The hyphal cells were multinucleate and the mycelia branched at a right angle. For molecular identification of the pathogen, mycelia of each isolate were cultured in potato dextrose broth at 26°C for a week, and genomic DNA was extracted from mycelia and used as a template for PCR amplification. The primers set of ITS1 and ITS4 was used for amplification of rDNA-ITS from these isolates and the amplified rDNA-ITS regions of all isolates (GenBank Accession Nos. KJ765700, KJ765701, and KJ765702, respectively) were 99% identical to other Waitea circinata deposited in GenBank (1,2). To further confirm the pathogenicity of the isolates, freshly collected PDA plugs were inoculated on the lower leaf blades of 8-week-old seedlings of the foxtail millet variety Yugu 1. PDA plugs without the isolate were used as a negative control. Five plants were used for each isolate and negative control. After inoculation, pots were placed together in a moist chamber at 26°C. No symptoms developed on the control plants, while obvious lesions appeared on the sheaths of tested plants at 5 days post inoculation and later the plants were lodging. The fungus was re-isolated from diseased plants and confirmed to be W. circinata based on morphological characteristics and sequence analysis as previously described, completing Koch's postulates. Further, on the basis of morphological tests, pathogenicity assays, and molecular analyses, the pathogen of foxtail millet sheath blight was identified as W. circinata (4). Although Rhizoctonia solani AG-1, AG-4 has been reported in earlier studies as the pathogen causing foxtail millet sheath blight, there has been no previous report of the disease caused by W. circinata (3). To our knowledge, this is the first report of foxtail millet sheath blight caused by W. circinata in China. With the spread of high millet plant density and fertilizer application, this disease may become a major threat to foxtail millet; therefore, W. circinata should be taken into account when designing measures for disease control in foxtail millet. References: (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (1) M. Fiers et al. Eur. J. Plant. Pathol. 128:353, 2010. (4) W. D. Gao. Acta Phytopathol. Sinica 17:247, 1987. (3) T. Toda et al. Plant Dis. 89:536, 2005.

Bioinformatic analysis of the nucleotide binding site-encoding disease-resistance genes in foxtail millet (Setaria italica (L.) Beauv.)

The nucleotide-binding site (NBS) disease-resistance genes are the largest category of plant disease-resistance gene analogs. The complete set of disease-resistant candidate genes, which encode the NBS sequence, was filtered in the genomes of two varieties of foxtail millet (Yugu1 and 'Zhang gu'). This study investigated a number of characteristics of the putative NBS genes, such as structural diversity and phylogenetic relationships. A total of 269 and 281 NBS-coding sequences were identified in Yugu1 and 'Zhang gu', respectively. When the two databases were compared, 72 genes were found to be identical and 164 genes showed more than 90% similarity. Physical positioning and gene family analysis of the NBS disease-resistance genes in the genome revealed that the number of genes on each chromosome was similar in both varieties. The eighth chromosome contained the largest number of genes and the ninth chromosome contained the lowest number of genes. Exactly 34 gene clusters containing the 161 genes were found in the Yugu1 genome, with each cluster containing 4.7 genes on average. In comparison, the 'Zhang gu' genome possessed 28 gene clusters, which had 151 genes, with an average of 5.4 genes in each cluster. The largest gene cluster, located on the eighth chromosome, contained 12 genes in the Yugu1 database, whereas it contained 16 genes in the 'Zhang gu' database. The classification results showed that the CC-NBS-LRR gene made up the largest part of each chromosome in the two databases. Two TIR-NBS genes were also found in the Yugu1 genome.