Sterigmatocystin — incidence, fate and production byA versicolor in ras cheese

Sterigmatocystin (STG) is a toxic metabolite produced by severalAspergillus species. Because of its toxic and carcinogenic properties the occurrence of STG in food is considered to represent a potential hazard to man. The present study was designed to investigate following points:

Identification of messenger and long noncoding RNAs associated with gallbladder cancer via gene expression profile analysis

The present study aimed to investigate the long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) involved in the progression of gallbladder cancer and explore the potential physiopathologic mechanisms of gallbladder cancer in terms of competing endogenous RNAs (ceRNAs). The original lncRNA and mRNA expression profile data (nine gallbladder cancer tissues samples and nine normal gallbladder samples) in GSE76633 was downloaded from the Gene Expression Omnibus database. Differentially expressed mRNAs and lncRNAs between gallbladder cancer tissue and normal control were selected and the pathways in which they are involved were analyzed using bioinformatics analyses. MicroRNAs (miRNAs) were also predicted based on the differentially expressed mRNAs. Finally, the co-expression relation between lncRNA and mRNA was analyzed and the ceRNA network was constructed by combining the lncRNA-miRNA, miRNA-mRNA, and lncRNA-mRNA pairs. Overall, 373 significantly differentially expressed mRNAs and 47 lncRNAs were identified between cancer and normal tissue samples. The upregulated genes were significantly enriched in the extracellular matrix (ECM)-receptor interaction pathway, while the downregulated genes were involved in the complement and coagulation cascades. Altogether, 128 co-expression relations between lncRNA and mRNA were obtained. In addition, 196 miRNA-mRNA regulatory relations and 145 miRNA-lncRNA relation pairs were predicted. Finally, the lncRNA-miRNA-gene ceRNA network was constructed by combining the three types of relation pairs, such as XLOC_011309-miR-548c-3p-SPOCK1 and XLOC_012588-miR-765-CEACAM6. mRNAs and lncRNAs may be involved in gallbladder cancer progression via ECM-receptor interaction pathways and the complement and coagulation cascades. Moreover, ceRNAs such as XLOC_011309-miR-548c-3p-SPOCK1 and XLOC_012588-miR-765-CEACAM6 can also be implicated in the pathogenesis of gallbladder cancer.     

Blood shizonticidal activities of phenazines and naphthoquinoidal compounds against Plasmodium falciparum in vitro and in mice malaria studies

Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment for malarial infection, 19 quinone derivatives with previously reported structures were also evaluated for blood schizonticide activity against the malaria parasite Plasmodium falciparum. These compounds include 2-hydroxy-3-methylamino naphthoquinones (2-9), lapachol (10), nor-lapachol (11), iso-lapachol (12), phthiocol (13) and phenazines (12-20). Their cytotoxicities were also evaluated against human hepatoma and normal monkey kidney cell lines. Compounds 2 and 5 showed the highest activity against P. falciparum chloroquine-resistant blood-stage parasites (clone W2), indicated by their low inhibitory concentration for 50% (IC₅₀) of parasite growth. The therapeutic potential of the active compounds was evaluated according to the selectivity index, which is a ratio of the cytotoxicity minimum lethal dose which eliminates 50% of cells and the in vitro IC₅₀. Naphthoquinones 2 and 5, with activities similar to the reference antimalarial chloroquine, were also active against malaria in mice and suppressed parasitaemia by more than 60% in contrast to compound 11 which was inactive. Based on their in vitro and in vivo activities, compounds 2 and 5 are considered promising molecules for antimalarial treatment and warrant further study.     

Expression of γ-H2AX and patient prognosis in breast cancer cohort

H2AX phosphorylation is a novel marker of DNA double-stranded breaks. In the present study, we assessed the γ-H2AX expression, its association with other clinicopathologic characteristics, and the prognosis in a cohort of 97 patients with breast cancer. Ninety-seven specimens of tumor tissue and 77 adjacent normal tissues from patients with breast cancer were examined. All patients underwent modified radical mastectomy or local tumor resection without lymph node dissection. γ-H2AX expression was assessed by standard immunohistochemistry. Patients were followed after surgery for a mean duration of 70.1 ± 18.7 months (range, 6-93 months). The γ-H2AX staining was positive in 27 (27.8%) patients. The positive rates of H2AX were 26.0% and 2.6% in tumor tissue and adjacent normal tissues, respectively. γ-H2AX positive status was negatively associated with TNM staging, with 24 positive cases (32.4%) in TNM staging I-II, while no positive cases in TNM staging III-IV (P = 0.026). Sixteen patients (16.5%) died during the follow-up. No significant association between γ-H2AX expression and patient survival was detected. The unadjusted HR (hazard ratio) for γ-H2AX positive was 0.84 (95% CI: 0.27, 2.60). In TNM staging subgroup analysis, death only occurred in γ-H2AX negative patients. Our study is the first study to demonstrate that expression of γ-H2AX is associated with TNM staging. Due to the small sample and limited follow-up time, we did not observe a significant association between γ-H2AX and patient survival. γ-H2AX expression could be a potential biomarker for cancer diagnosis and prediction, and further studies are in need.     

Development of PCR primers from internal transcribed spacer region 2 for detection of Phytophthora species infecting potatoes.

We developed PCR primers and assay methods to detect and differentiate three Phytophthora species which infect potatoes and cause late blight (Phytophthora infestans) and pink rot (P. erythroseptica and P. nicotianae) diseases. Primers based on sequence analysis of internal transcribed spacer region 2 of ribosomal DNA produced PCR products of 456 bp (P. infestans), 136 bp (P. erythroseptica), and 455 bp (P. nicotianae) and were used to detect the pathogens in potato leaf (P. infestans) and tuber (P. infestans, P. erythroseptica, and P. nicotianae) tissue with a sensitivity of 1 to 10 pg of DNA. Leaf and tuber tissue were processed for PCR by a rapid NaOH method as well as a method based on the use of commercially available ion-exchange columns of P. infestans primers and the rapid NaOH extraction method were used to detect late blight in artificially and naturally infected tubers of potato cultivar Red LaSoda. In sampling studies, P. infestans was detected by PCR from artificially infected tubers at 4 days postinoculation, before any visible symptoms were present. The PCR assay and direct tissue extraction methods provide tools which may be used to detect Phytophthora pathogens in potato seedlots and storages and thus limit the transmission and spread of new, aggressive strains of P. infestans in U.S. potato-growing regions.     

Detection and estimation of aflatoxins using both chemical and biological techniques

Production of aflatoxins on both natural (rice and corn) and semisynthetic (YES) media was conducted using an identified toxin-producing strain ofAspergillus flavus. TheA flavus strain was able to produce 4 types of aflatoxins, namely B₁, B₂, G₁, and G₂ on rice, corn, and YES media. Quantitative data showed that the concentrations of aflatoxins B₁ and G₁ produced were 52, 40.3, and 39.6; and 64.7, 45.0, and 58.0jug for 50g of rice, corn, and YES media, respectively. In comparison, the yielded amounts of aflatoxins B₂ and G₂ were much lower: 11.5, 17.9, and 17.5; and 28.S, 40.3, and 39.5 μg for 50 g of rice, corn, and YES media, respectively. A bioassay was conducted using the following 5 standard bacterial strains:Bacillus megaterium. Bacillus subtilis, Streptococcus faecal is, Staphylococcus epidermidis, andParacoccus denitrificans as well as a field strain of Candida albicans. All strains exceptP denitrificans showed varied degrees of inhibition when applied with crude aflatoxins at 5 to 40μg/mL. The minimum concentration of crude aflatoxins needed to inhibitP denitrificans was 10μg/mL. Moreover,Candida albicans was not inhibited at any concentration of aflatoxins applied in this work. Both undiluted and diluted (1/10, 1/100, and 1/1000) bacterial broth cultures showed a direct relationship between the diameter of inhibition zones and the concentrations of crude aflatoxins. Mean diameters of (7.0–20.5), (5–14), (4.5–13.0), (3.0–12.0), and (1.5–11.0) mm were observed when various concentrations of aflatoxins were applied usingB megaterium, S epidermidis, S faecal is, B subtilis, andP denitrificans, respectively. Field trials were applied to testify the validity of our data. A 1/100 dilution was prepared from each strain of 4 different species to estimate aflatoxins in samples of contaminated corn. Both chemical and biological assays were carried out at the same time. Data revealed that the most sensitive organism inhibited by as low as 7.5μg aflatoxins/mL wasB megaterium giving an inhibition zone of 10.5 mm, followed byS epidermidis with an inhibition zone of 7.5mm. In relation, the other 2 organisms were less sensitive to crude aflatoxins. Similarly, the biological assay was applied to detect aflatoxins in some samples of wheat, corn, peanut, rice, and poultry rations. Of the 14 wheat and 10 corn samples, only 4 wheat and 2 corn samples were found to be positive. The same results were obtained using TLC analysis.