الغامدي، ابتهال عبدالقادر عبدالله

Ti-based alloys are characterized by a diverse metallurgy, which allows obtaining a wide palette of microstructural configurations and physical properties via careful selection of chemical composition and heat treatment processes. The present work aims to expand the current state of knowledge about the influence of alloying elements and various heat treatment conditions on the structural and mechanical properties, as well as corrosion resistance of three different Ti-based alloys; TiAl6V4 (TAV), TiAl6Nb7 (TAN) and TC21. There are two types of solution heat treatment were carried out followed by aging treatment one. In the first solution heat treatment, the specimens were solution treated at 900˚C for 1 h followed by water quenching (WQ) and it called single stage solution treatment (SSST). In the other solution heat treatment, the specimens were solution treated at 900˚C for 15 min followed by furnace cooling to 700˚C with a cooling rate 1˚C/min and holding for 15 min, then the specimens cooled down to room temperature using water quenching, this treatment named double stage solution treatment (DSST). Consequently, for specimens treated with both types of solution treatment processes, aging heat treatment was applied at 550˚C for different duration of times ranging from 2h to 8 h, followed by air cooling (AC). The microstructure, after different heat treatment conditions, is analyzed by using scanning electron microscope (SEM) and in-situ synchrotron X-ray diffraction to recognize different phases in the microstructure. Moreover, Differential scanning calorimetry (DSC) was used to determine the transus temperature of beta () phase (T), to ensure that the solution treatment accomplished under T in the (+) range. Hardness property was measured representing the mechanical properties of investigated heat treated Ti-based alloys. Hardness measurements are also used to investigate the correlation of the microstructure after the heat treatments with the mechanical properties. The microstructure feature showed a secondary α phase (αs) precipitated in residual β phase due to the step cooling from 900˚C to 700˚C inside furnace as well as the aging treatment. Optimum mechanical properties of the studied Ti-alloys were obtained for TC21 alloy that solutionized by SSST + Aging condition. A better combination of hardness, tensile v properties, and corrosion resistance was achieved for DSST + Aging specimens, although their hardness was found to be slightly lower than that of SSST + Aging specimens. Keywords: Ti-based alloys, microstructure, heat treatment, SEM and XRD, mechanical properties.

العتيبي ، مها زايد هوشان

مراد ، مريم عبد الستار بيك

هبل، أحمد سليمان علي

Bacillus subtilis group is constitutes the core of Bacillus spp, one of the important species in biotechnological industry and agriculture. But they are also associated with food spoilage and food-borne disease. They are also considered potential surrogates to studied of Bacillus anthracis and other bacilli. Endospore-forming Bacillus are taxonomically and physiologically diverse, and are ubiquitous members of soil, water and food microbial communities. The climatic variation and diversity of isolation habitats provide the opportunity of isolating Bacillus strains new. The local strains were isolated of B. subtilis group from various habitats in different areas of Taif, was based on selective heating methods. 56 the Bacillus isolates were isolated from different samples; 24 of these isolates were shown to belong to B. subtilis group. According to morphological, biochemical and molecular identification of wild isolates, we confirmed isolates as B. subtilis, B. pumilus and B. xiamenensis. The process of sporulation is a survival strategy for species belonging to the Bacillus genus. The mechanism of sporulation is largely conserved amongst these species. All strains of this study were grown on onto difco sporulation medium (DSM) to foster sporulation. Spore dimensions were determined by scanning electron microscopy. The results indicate, that there are large variations in the spore sizes, due to differences in the environmental niches in which these bacteria thrive and the amount of water remaining in the spore during preparation. The germination studies are an important tool for understanding differences between species and strains. Our lab strain B. subtilis 168 and three other wild strain spores were tested for spore germination in various concentrations of L-alanine and AGFK. Results showed these study, that spores of all strains germinated in L-alanine, and AGFK except for the B. xiamenensis showed no germinated in AGFK. The wild strains were less responsive to low concentrations of L-alanine, and in some strains, there was a long average microlag before germination in the population. This study involved the selection and use of primers specific for GerA operons and GerB operons. PCR results showed that genes of the GerA operons are more conserved than GerB in all strains. This study was applied to the positive plant growth promoting rhizobacteria PGPR) out of B. subtilis wild isolates in biological control. Fungal isolates were isolated from rotting plant roots. The isolates were identified according to standard methods. Antifungal effect of the bacterial isolates was tested by measuring the growth inhibition zone of fungal pathogen on petri dishes. Results of this study from bioassays in dual culture suggest that production of antifungal substance by wild isolates may be involved in the inhibition of hyphal growth of fungl. In the pot experiment, the biocontrol reduced the concentration of Fusarium solani and Rhizoctonia solani. The results have shown that fresh weight, shoot length and root length of tomato and cucumber were significantly increases in the biologically treated groups as compared to the positive control group.

الحارثي، عهود فيصل محيا

The emerging of infectious diseases and broad use of antibiotics led to the spread resistance between pathogenic bacteria. Nanoparticles considered an alternative to antibiotics to eliminate infectious diseases. In this study, antibacterial and antibiofilm activities of gold nanoparticles on five human pathogenic bacteria including Salmonella Typhimurium, Escherichia coli, Shigella sonnei, Enterococcus faecalis and Pseudomonas aeruginosa were studied. In addition, the effect of gold nanoparticles on whole cell protein, heat shock protein and biofilm associated genes expressions was also investigated. Transmission electron microscope (TEM) of chemical synthetized gold nanoparticles (AuNPs) showed triangular forms with size ranged from 50 to 750 nm. AuNPs showed activity against pathogenic bacteria and the minimum inhibitory concentration (MICs) values were ranged from 0.05 to 0.1 mg/ml. Antibiofilm activity of AuNPs on polystyrene using crystal violet and on glass using MTT techniques was variable. Furthermore, RT-PCR showed decrease in the expression levels of hilA and fimH genes, whereas those of ipaH, agg and rhlI genes were significantly increased after treatment with AuNPs. Moreover, SDS-PAGE demonstrated a decrease in the expression levels of almost major proteins and a reduction in the whole cell proteins quantities except of P. aeruginosa. In addition, Western blot analysis showed a considerable increase of GroEL heat shock protein expression level in all tested bacteria. However, variable expression level were studied for GroES protein. Keywords: Pathogenic bacteria, AuNPs, Antibacterial, Antibiofilm, Whole cell proteins, Heat shock proteins, Biofilm associated genes.

الحارثي ، عهود فيصل محيا

The emerging of infectious diseases and broad use of antibiotics led to the spread resistance between pathogenic bacteria. Nanoparticles considered an alternative to antibiotics to eliminate infectious diseases. In this study, antibacterial and antibiofilm activities of gold nanoparticles on five human pathogenic bacteria including Salmonella Typhimurium, Escherichia coli, Shigella sonnei, Enterococcus faecalis and Pseudomonas aeruginosa were studied. In addition, the effect of gold nanoparticles on whole cell protein, heat shock protein and biofilm associated genes expressions was also investigated. Transmission electron microscope (TEM) of chemical synthetized gold nanoparticles (AuNPs) showed triangular forms with size ranged from 50 to 750 nm. AuNPs showed activity against pathogenic bacteria and the minimum inhibitory concentration (MICs) values were ranged from 0.05 to 0.1 mg/ml. Antibiofilm activity of AuNPs on polystyrene using crystal violet and on glass using MTT techniques was variable. Furthermore, RT-PCR showed decrease in the expression levels of hilA and fimH genes, whereas those of ipaH, agg and rhlI genes were significantly increased after treatment with AuNPs. Moreover, SDS-PAGE demonstrated a decrease in the expression levels of almost major proteins and a reduction in the whole cell proteins quantities except of P. aeruginosa. In addition, Western blot analysis showed a considerable increase of GroEL heat shock protein expression level in all tested bacteria. However, variable expression level were studied for GroES protein

القرني ، شروق ناصر

The black Aspergilli species and their relevant mycotoxins have been investigated in a number of fruits-producing regions around the world. However, similar data have not been reported for some fruits that studied in this research. From October to December of 2015, 540 black aspergilli were isolated from 100 fruit samples, including: Pyrus communis, Fragaria ananasa, Vitis vinifera, Punica granatum and Psidium guajava. Twenty-seven species belonging to black Aspergilli were isolated and identified using classical and PCR-based methods. The most common species were A. niger 22 in Pyrus communis and Fragaria ananasaa samples, A. niger 23 in Vitis vinifera samples, A. niger 12 in Punica granatum samples and A. niger 2 in Psidium guajava samples based on the count and the number of cases of isolation, which represented 12.3%, 17.4%, 16.7%, 15.8% and 21.5% of total black Aspergilli, respectively. 27representative isolates were selected from black Aspergilli collected from Pyrus communis to complete the rest of the studies.The identification of collected black Aspergilli were confirmed by ITS sequincing that indicated to the correspondence between the molecular identification of the isolated black Aspergilli and the morphological identification. They were listed under one main species ( A. niger). The ranges of OTA in all tested strains were 0.18-9.5 ppb. Whereas, OTA disappeared in some strains. All strains were subjected for detecting two of ochratoxin biosynthesis (PKS15C-MeT and PKS15KS) genes. At least one gene in the isolates was sufficient to differentiation between ochratoxigenic and non ochratoxigenic isolates. Genetic diversity among A. niger strains did not show any relationship between the strains clustering system and the ochratoxigenic potentials of strains

الخماش ، أسماء أحمد

الحارثي،هلال فرج سعيد

1436/2014 Sixty samples of poultry and animal feed stuff samples were collected from three cities in Saudi Arabia (Jeddah, Makkah and Taif), for isolation and identification of fungi and aflatoxins contaminated samples. The dilution plate method used for the estimation of fungi from poultry and animal feeds on Potato Dextrose Agar (PDA) and Dichloran Rose-Bengal Chloramphenicol Agar (DRBC) at 27º C. The average total counts of isolated fungi on PDA and DRBC medium were 6.072 X103 and 9.8802 X103 CFU/g. Fifty five species belonging to 13 genera were isolated and identified in the present study using classical and PCR-based methods (Internal Transcribed Spacer region sequencing). The most common genera were Aspergillus, penicillim and Fusarium. Aspergillus flavus , A. niger were the most prevalent aspergilla A. flavus was the most common species based on the count and the number of cases of isolation, which was recovered from 56 and 59 samples, comprising 59.2 % and 53.7 % of total aspergilli and 36.3% and 31.7% of total fungi on PDA and DRBC media, respectively. Aspergillus amstelodami, A. chevalieri, A. oryzae and A. terreus were isolated with moderate frequencies of occurrence recovering collectively from 36 and 48 samples, which comprising collectively 11.4 % and 17.2 % of total aspergilli but comprising 7.0 % and 10.2 % of total fungi on PDA and DRBC media, respectively. All investigated feedstuff samples were contaminated with total aflatoxins (AFs) and the range of AFs was 0.61 – 60 ppb. The range of AFs levels in poultry, cattle and camel & cattle samples were 0.90 - 60, 1.0 – 7.6 and 1.3 – 13 ppb, respectively. The aflatoxins potentials were detected in all collected isolates of Aspergillus. The percentage of aflatoxigenic isolates of Aspergillus flavus among 115 isolates were tested was 74.7%. All of 30 isolates collected from A. nomius were aflatoxigenic. Among collected isolates of Aspergillus parasiticus 13 isolates out of 17 (76.5%) were aflatoxigenic. The ranges of AFs in A. flavus, A. nomius and A. parasiticus isolates were 3.7 – 110, 20.5- 165.3 and 143.6 – 271.3 ppm, respectively. Sixty four and 17 representative isolates of aflatoxigenic and non aflatoxigenic Aspergillus flavus and A. parasiticus isolates were subjected for detecting some of aflatoxin biosynthesis (aflR, omt-1, ver-1 and nor-1) genes. The examined Aspergillus flavus and A. parasiticus isolates yielded different DNA banding patterns corresponding to the targeted genes. Also, some of non aflatoxigenic isolates contained the 4 targeted genes. The results of this work indicated clearly that the presence of four tested genes is not sufficient marker for differentiation between aflatoxigenic and non aflatoxigenic isolates. Genetic diversity among 64 isolates of collected Aspergillus flavus using the results of ITS sequencing and presence of absence of Aflatoxin biosynthesis genes indicated no correlation between clustering systems and geographical or toxingenic potentials of isolates. This result confirmed the high heterogeneity among Aspergillus flavus isolates.

القزلان ، ندى عبدالله محمد

Human Cytomegalovirus (HCMV) represents the most common Viral disease in not only pregnant women with possible subsequent abortion, but also as a leading infectious cause of birth defects and neurodevelopmental delay, with worst outcomes in congenital infection. This highlights the importance of the accurate determination of immune status during pregnancy. Maternal HCMV infection is often asymptomatic, thus the diagnosis can only be achieved by serological tests for HCMV—specific immunoglobulin IgG and IgM are and/or the determination of HCMV-DNA. HCMV infection in pregnancy is barely studied in Saudi Arabia. The aim of this thesis was to screen HCMV infection among pregnant population in maternity unit of Alhada hospital for armed forces and to describe the associated factors with seropositivity. A total of 200 participated pregnant women were studied cross-sectionally in their first, second and third trimester to determine the prevalence of both IgG/IgM antibodies as well as HCMV specific DNA among pregnant women. A questionnaire was used to gather sociodemographic and clinical factors. All serum samples were tested for CMV-IgG and IgM assays for seropositive by automated chemiluminescence immunoassay (CLIA) methods. Molecular analysis was carried out for screening the presence of HCMV-DNA using real time PCR (qPCR) technique. Of the 200 pregnant women, 197 (98.5%) were found seropositive for CMV IgG antibodies, with only two samples one positive for HCMV IgM positive and the other positive for HCMV viral DNA. The pregnant women with history of bad obstetrics showed high IgG titer. The seropositivity of HCMV was more detected in those pregnant women within the third trimester (62.9%) of pregnancy. Among IgG seropositive group, 17.7% had obstetric history of miscarriage, stillbirth, and birth defect. (79.7%) were in the second or subsequent pregnancies. The study concluded that HCMV exposure was high in this study population with low rates of recent primary infection. Further studies with large numbers of participants are recommended. Education regarding preventive measures for HCMV infection in antenatal care has a value as some proportion were seronegative for HCMV were prone to get new infections.

العتيبي ، منيرة حمود جابر

العوفي ، أفنان ضيف الله عبيد الله

Staphylococcus aureus is an important opportunistic human pathogen in human that causes wide range of infectious conditions both in nosocomial and community settings. This microorganism is known for its ability to acquire resistance to various antibiotic classes. The emergence and spread of methicillin-resistant S. aureus (MRSA) strains that are often multi-drug resistant in hospitals and subsequently in community resulted in significant mortality and morbidity. In total, 179 S. aureus isolates were obtained from nasal swabs of different healthy females students belonging to medical faculties and nonmedical faculties in Taif University. The isolates were presumptively identified as S. aureus by The BD max Nasal Complete Assay. six of the isolates were methicillin-resistant S. aureus (MRSA), whereas 38 were methicillin susceptible (MSSA). All S. aureus isolates were subjected to antimicrobial susceptibility testing by phenoix. The selected MRSA was enrolled for SCCmec typing using multiplex PCR and PVL gene using PCR. MRSA isolates showed resistance of 100% to Penicillin G, Oxacillin, Amoxicillin-Clavulanate, Imipenem, Cefotaxime, Ampicillin, Cefoxitin. In addition, 33.3% of the MRSA isolates were resistant to Erythromycin. However, 16.6% were to Trimethoprim-Sulfamethoxazole and Clindamycin. SCCmec typing showed the existence of two profiles and the respective isolates are classified as Community-Associated Methicillin-Resistant Staphylococcus Aureus (CA-MRSA). Further, PCR detection of PVL gene demonstrated that only three MRSA isolates harbor this gene.

العوفي، أفنان ضيف الله عبيد الله

Staphylococcus aureus is an important opportunistic human pathogen in human that causes wide range of infectious conditions both in nosocomial and community settings. This microorganism is known for its ability to acquire resistance to various antibiotic classes. The emergence and spread of methicillin-resistant S. aureus (MRSA) strains that are often multi-drug resistant in hospitals and subsequently in community resulted in significant mortality and morbidity. In total, 179 S. aureus isolates were obtained from nasal swabs of different healthy females students belonging to medical faculties and nonmedical faculties in Taif University. The isolates were presumptively identified as S. aureus by The BD max Nasal Complete Assay. six of the isolates were methicillin-resistant S. aureus (MRSA), whereas 38 were methicillin susceptible (MSSA). All S. aureus isolates were subjected to antimicrobial susceptibility testing by phenoix. The selected MRSA was enrolled for SCCmec typing using multiplex PCR and PVL gene using PCR. MRSA isolates showed resistance of 100% to Penicillin G, Oxacillin, Amoxicillin-Clavulanate, Imipenem, Cefotaxime, Ampicillin, Cefoxitin. In addition, 33.3% of the MRSA isolates were resistant to Erythromycin. However, 16.6% were to Trimethoprim-Sulfamethoxazole and Clindamycin. SCCmec typing showed the existence of two profiles and the respective isolates are classified as Community-Associated Methicillin-Resistant Staphylococcus Aureus (CA-MRSA). Further, PCR detection of PVL gene demonstrated that only three MRSA isolates harbor this gene. v Keywords: S. aureus, MRSA, Antibiotic resistance, SCCmec typing, PVL gene

المقذلي،بشائر حسين مصلح

Forty isolates were recovered from 60 food of animal origin samples collected from the restaurant of the local market at Taif City, Kingdom of Saudi Arabia. Forty pathogens were isolated and identified biochemically and seryologically. These pathogens were Bacillus cereus (10 isolates) Salmonella spp. (5 isolates), Staphylococcus aureus (18 isolates) and Escherichia coli (7 isolates). Ten multi-drug resistant strains were selected for further work. These strains were resist to 7 antibiotics (Staph. aureus , E. coli O:128. H2 and E. coli O:125. H21) 6 antibiotics (S. Muenster, S. Typhimurium, E. coli O: 119. H6, E. coli O: 111. H 4) and 5 antibiotics (B. cereus and S. Enteirica). The identification of these strains was confirmed by determining partial sequence of 16S rRNA gene. Biofilm formation by these strains was studied under different conditions including the presence of 1% trypsin, 1% lysozyme and 3% bile salts at pH 4, 7 and 8. The effect of simulated gastrointestinal juice(SGIJ) was also studied at the above mentioned pH values. Trypsin showed high efficiency to reduce biofilm formation while lysozyme and bile salts led to attenuate biofilm forming ability. No significant difference was recorded in biofilm forming ability of the studied strains when the pH of SGIJ was adjusted at 7 compared with control. However, at pH 4 and 8 sharp decrease in the biofilm forming ability was obtained. In conclusion, the present study demonstrated that although the isolated pathogens lost partial of their ability to form biofilm at pH 4 and 8, they still have ability to form biofilm after exposure to SGIJ. Therefore, more attention should be taken in the consideration to avoid the presence of these pathogens in foods. These could be achieved by follow the hygienic procedures recommended by the governmental authorities.

النمري ، فايزة محمد أحمد

Psychrotrophic counts using standard method were 56130, 240930,19280,156670,and15 4290 ̸cfu ml of raw milk ,cream, yoghurt, fermented milk and ice cream sample respectively . Out of isolated psychrotrophs (7̊C ̸ 10 days) from raw milk, cream, yoghurt, fermented milk & ice cream 5(15.63%),2(7.41%), 5(20.83%),4(16.00%)&3(15.79%) were ps. fluorescens; 3(9.38%),3(9.38%) , 1(3.70%)&1(5.26%) were ps. putrefaciens from raw milk ,cream & ice cream, while negative for yoghurt& fermented milk;3(9.38%), 3(11.11%),1(4.17%),2(8.00%)&3(15.79%) ,were ps. cepacia from raw milk ,cream, yoghurt, fermented milk and ice cream sample respectively ; 1(3.70%) &1(5.26)were Ps. aeruginosa from cream & ice cream sample respectively, while were negative for raw milk, yoghurt& fermented milk sample respectively. 1(3.13%), 1(3.13%) &2(8.00%) were ps. acidoverans from raw milk, yoghurt& fermented milk sample respectively while were negative for cream& ice cream sample respectively;1(3.13%),2(7.41%), 1(4.17%),1(4.00%)were ps. putida for raw milk ,cream, yoghurt& fermented milk sample respectively, while were negative for ice cream sample ; 4(12.50%),6(22.22%), 2(8.33%) , 3(12.00%) &3(15.79%)were Alcaligenes faecalis from raw milk ,cream, yoghurt, fermented milk & ice cream sample respectively ;1(3013%) , 1(4.17%) , 2(8.00%) were Alcaligenes viscolactis fromr negative for, yoghurt& fermented milk sample respectively, while were negative for cream& ice cream sample respectively . ;3(9,38%) , 2(7.41%) , 1(5.26%) Acinetobacter iwafii from raw milk ,cream, & ice cream sample respectively, while were negative for yoghurt&fermented milk ;1(3.13%)were Actinetobacter mallei from raw milk sample,isolated 18 samples. Bacterial identification finally based on detection of 16Sr RNA the amplification of 16SrRNA.