Agar Culture (agar + culture)

Distribution by Scientific Domains

Selected Abstracts

Physicochemical properties of Shiga toxigenic Escherichia coli

L. Rivas
Abstract Aims:, To investigate the physicochemical surface properties, such as cellular surface charge, hydrophobicity and electron donor/acceptor potential of a selection of Shiga toxigenic Escherichia coli (STEC) isolates grown in broth and agar culture. Methods and Results:, Cellular surface charge was determined using zeta potential measurements. Hydrophobicity of the isolates was determined using bacterial adhesion to hydrocarbons assay, hydrophobic interaction chromatography and contact angle measurements. Microbial adhesion to solvents was used to determine the electron donor/acceptor characteristics. No differences of surface charge measurements were found between broth and agar grown cultures. Isolates belonging to serogroup O157 and serotypes O26:H11 and O111:H- were significantly (P < 005) less negatively charged than other STEC serotypes tested. All strains were hydrophilic with most methods and demonstrated a lower hydrophobicity in agar culture compared with broth culture. All strains demonstrated a strong microbial adhesion to chloroform indicating that STEC possess an electron donor and basic character. A relationship between serogroup O157 and other STEC serotypes was apparent using principal-component analysis (PCA). Conclusions:, Combining the results for physicochemical properties using PCA differentiated between strains belonging to the O157 serogroup and other STEC/non-STEC strains. PCA found similar results for broth and agar grown cultures. Significance and Impact of the Study:, Particular serotypes of STEC possess similar physicochemical properties which may play a role in their pathogenicity or potential attachment to various surfaces. [source]

A Suspension Culture Method for the Rapid Mass Culture of Cistella japonica Mycelium

T. Yamanobe
Abstract Different methods were investigated for the rapid mass culture of Cistella japonica by using water extracts of some nutritional sources. In an agar culture test, there was little difference in mycelial growth in water extracts of wheat bran, rice bran and potato. In suspension culture with wheat bran extract, which is easily and cheaply available, the mycelium of C. japonica increased seven times more than that in agar culture after a month's incubation. C. japonica from suspension culture was pathogenic to Chamaecyparis obtusa. These results suggest that suspension culture in water extract of wheat bran can be adopted for the rapid mass culturing of C. japonica for use in inoculation tests. [source]

A Chinese,Japanese boy with black dot ringworm due to Trichophyton violaceum

ABSTRACT A 4-year and 8-month-old Chinese-Japanese boy, who had been visiting Dalian, China frequently, developed multiple alopecia lesions 1 year previously. At his initial visit to our department, multiple patchy alopecia with black dots was observed in the parietal scalp area. Multiple erythematous macules were also seen on the face, nape and right dorsum of the hand. A diagnosis of tinea capitis and tinea corporis was obtained on the basis of potassium hydroxide (KOH) microscopic examination of hair and scales from the lesions. Colonies grown on Sabouraud cycloheximide-chloramphenicol agar culture were examined using Fungi-Tape and MycoPerm-blue, and numerous microconidia and a small number of macroconidia were observed. Trichophyton violaceum was identified as the causative organism on the basis of colony morphology, microscopic morphology and molecular biology technique. As T. violaceum infection is not often seen in Japan, we suspected that the patient was infected by T. violaceum during his stay in Dalian. Conidia formation is rarely observed with T. violaceum, and only five cases with T. violaceum macroconidia formation have been reported in Japan (including this case). We also report the method for visualizing conidia formation of T. violaceum using Fungi-tape and MycoPerm-blue. [source]

Flow cytometric method for quantifying viable Mycoplasma agassizii, an agent of upper respiratory tract disease in the desert tortoise (Gopherus agassizii)

H.A. Mohammadpour
Abstract Aims:,Mycoplasma agassizii can cause upper respiratory tract disease in the threatened desert tortoise of the Southwestern United States. Two technical challenges have impeded critical microbiological studies of this microorganism: (i) its small size limits the use of light microscopy for cell counting and (ii) its extremely slow growth in broth and agar cultures impedes colony counting. Our aim was to develop a rapid and sensitive flow cytometric method using a vital fluorescent dye to enumerate viable M. agassizii cells. Methods and Results:, Here, we demonstrate that the nonfluorescent molecule 5-carboxyfluorescein (5-CF) diacetate acetoxymethyl ester penetrates M. agassizii cell membranes and it is converted in the cytoplasm to the fluorescent molecule 5-CF by the action of intracellular esterases. Labelled mycoplasma cells can be easily detected by flow cytometry, and cultures with as few as 100 viable mycoplasma cells ml,1 can be labelled and counted in less than 1 h. Experiments using temperature-induced cell death demonstrated that only viable M. agassizii cells are labelled with this procedure. Conclusions:, A rapid and sensitive flow cytometric technique has been developed for enumerating viable M. agassizii cells. Significance and Impact of the Study:, This technique should facilitate basic immunological, biochemical and pharmacological studies of this important pathogen which may lead to new diagnostic and therapeutic methods. [source]