Expression of genes encoding cellulolytic enzymes in some Aspergillus species.

Fermentation is an important industrial process for microbial metabolite development and has wide applications in various fields. Aspergillus is the most important genus of fungi used for the production of microbial enzymes such as cellulase. The Aspergillus genome encodes various cellulolytic enzymes. In this study, we assayed the gene expression and cellulolytic enzyme production of three isolates: A. niger (KSU009), A. terreus (KC462061), and A. flavus (KSU014). Two fermentation systems, submerged fermentation and biofilm fermentation (BF), were used for this purpose. Gene expression analysis by RT-PCR showed that cbhB, exo, eglA, eglB, eglC, and ß-actin genes were differentially expressed in the two fermentation systems for these three isolates during enzyme production. Furthermore, the expression of all genes was found to be higher in the BF system. The six genes were not expressed in the isolates with no cellulolytic enzyme production. The isolates were identified by morphological and molecular methods, which were based on macroscopic characteristics and sequence analysis of ITS1, ITS2, and the 5.8S regions of rDNA.

Molecular characterization of aflatoxigenic and non-aflatoxigenic Aspergillus flavus isolates collected from corn grains.

Twelve species from six fungal genera were found to be associated with corn (Zea mays L.) grain samples collected from three main regions of Saudi Arabia. The average frequencies of the most common genera were Aspergillus (11.4%), Fusarium (9.5%), Penicillium (5.1%), and Alternaria (5.8%). Fifteen isolates of Aspergillus flavus were screened by HPLC for their ability to produce aflatoxins (AF). The percentage of aflatoxigenic A. flavus isolates was 53%. Eight isolates produced AF, at concentrations ranging 0.7-2.9 ppb. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) molecular markers were used to genetically characterize isolates of A. flavus and to discriminate between the aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, which was useful for genetic characterization. The clustering in the RAPD and ISSR dendrograms obtained was unrelated to geographic origin. The RAPD and ISSR markers could not discriminate between aflatoxigenic and non-aflatoxigenic isolates, but the ISSR primers were somewhat better.

Molecular characterization of Aspergillus flavus and aflatoxin contamination of wheat grains from Saudi Arabia.

Twelve species belonging to six fungal genera were found to be associated with wheat (Triticum aestivum L.) grain samples collected from three main regions in Saudi Arabia. The most common genera (average frequency) were Aspergillus (14.3%), Fusarium (29.1%), Penicillium (9.3%), and Alternaria (8.2%). Nineteen isolates of Aspergillus flavus were screened for their ability to produce aflatoxins using HPLC. Thirteen isolates produced aflatoxins ranging from 0.5 to 2.6 µg/kg. Inter-simple sequence repeats (ISSR), and random amplified polymorphic DNA (RAPD) molecular markers were used, with the aim of genetically characterizing strains of A. flavus to discriminate between aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, useful for genetic characterization. Clustering based on RAPD and ISSR dendograms was unrelated to geographic origin. RAPD and ISSR markers were not suitable to discriminate aflatoxigenic and non-aflatoxigenic isolates, but ISSR primers were better compared to RAPD.

Molecular characterization of the pathogenic plant fungus Rhizoctonia solani (Ceratobasidiaceae) isolated from Egypt based on protein and PCR-RAPD profiles.

Twenty-one isolates of Rhizoctonia solani were categorized into three anastomosis groups consisting of AG-4-HG-I (eight isolates), AG-2-2 (nine isolates) and AG-5 (four isolates). Their pathogenic capacities were tested on cotton cultivar Giza 86. Pre-emergence damping-off varied in response to the different isolates; however, the differences were not significant. Soluble proteins of the fungal isolates were electrophoresed using SDS-PAGE and gel electrophoreses. A dendrogram of the protein banding patterns by the UPGMA of arithmetic means placed the fungal isolates into distinct groups. There was no evidence of a relationship between protein dendrogram, anastomosis grouping or level of virulence or geographic origin. The dendrogram generated from these isolates based on PCR analysis with five RAPD-PCR primers showed high levels of genetic similarity among the isolates from the same geographical locations. There was partially relationship between the genetic similarity and AGs or level of virulence or geographic origin based on RAPD dendrogram. These results demonstrate that RAPD technique is a useful tool in determining the genetic characterization among isolates of R. solani.

Mean glycosylated hemoglobin in children with type 1 diabetes at King Fahad Medical City, Riyadh, Saudi Arabia.

BACKGROUND: Type 1 diabetes is the third most common chronic disease among teenagers. In Saudi Arabia, there is a gap of knowledge regarding hemoglobin A1C (HbA1c) concentration levels, and adherence to regular follow-up visits by patients. The aim of this study was to determine the mean glycosylated hemoglobin (HbA1c) levels in diabetic children who have been diagnosed with type 1 diabetes and were being followed up at a tertiary care center in Saudi Arabia. MATERIALS AND METHODS: This cross-sectional study was conducted among all diabetic children treated at King Fahad Medical City (KFMC) in Riyadh, Saudi Arabia. Data were retrieved and analysed during the period from September to December 2018. Diabetic patients of <18 years and who were being followed up at KFMC were included in the study. Data on age, sex, duration of illness, associated comorbidities, antidiabetic regimen, and HbA1c levels were obtained. Student t-test was used to compare quantitative parameters between two groups, and Chi-square employed to test for associations between categorical variables at 5% significance level. RESULTS: A total of 510 patients of were included in the study; about 53% were females. The mean HbA1c level was 10.6% and females showed higher HbA1c levels. Data showed a strong correlation between age and HbA1c levels (P < 0.001), with older patients showing higher HbA1c levels. The HbA1c levels also increased as the duration of disease increased. The median number of patient visits to KFMC was two per year. No statistically significant differences were observeed for type of treatment for diabetes. Celiac disease, the most frequent comorbidity, was seen in 50% of patients. CONCLUSION: Diabetic children who were followed up at KFMC had high HbA1C level (10.6%), and lower than recommended follow-up visits per year. The treating physicians should educate patients and their legal guardians on the importance of follow-up visits and their role in controlling HbA1C levels, and following healthier lifestyle.

Radiotherapy alone for clinical T4 skin carcinoma of the head and neck with surgery reserved for salvage.

PURPOSE: To evaluate the outcomes of definitive radiotherapy in the treatment of clinical stage T4 cutaneous carcinomas of the head and neck. PATIENTS AND METHODS: Between October 1964 and September 1997, 85 patients with 88 biopsy-proven clinical AJCC stage T4 carcinomas of the skin of the head and neck received radiotherapy with curative intent. A total of 43 lesions were previously untreated, and 45 were recurrent after other treatment modalities. Histologic types of carcinoma included squamous cell (37 lesions), basal cell (41 lesions), and metatypical basal (basosquamous) cell (10 lesions). Minimum follow-up was 2 years. The product-limit method was used to determine the rates of disease control, severe late complications, and survival. Multivariate analyses included histology, previous treatment, involvement of bone or nerve, number of structures invaded, node stage, external beam dose, and overall treatment time. RESULTS: At 5 years, the rates of local control after radiotherapy and ultimate local control after salvage surgery were 53% and 90%, respectively. Local control rates were better for patients having previously untreated lesions (P =.05). Regional and ultimate regional control rates were 93% and 100%, respectively, and were better for previously untreated lesions (P <.01), basal cell histology or its metatypical variant (P =.04), and absence of bone invasion (P =.08). At 5 years, the risk of severe late complications was 17%, the risk of distant metastasis was 5%, and the overall absolute and cause-specific survival probabilities were 56% and 76%, respectively. CONCLUSION: Radiotherapy alone results in a relatively high probability of cure for selected patients with T4 skin cancers.