A karyotypic study on Silene sect. Sclerocalycinae in Turkey

The karyology of fifteen taxa of Silene sect. Sclerocalycinae from Turkey has been investigated. Karyotype analyses has been carried out and the chromosome number of Silene caramanica, S. peduncularis, S. armena, S. laxa, S. swertiifolia, S. caesarea, S. sclerophylla, S. haradjianii and S. lycaonica have been determined for the first time. For all the taxa studied, the diploid chromosome number and the basic chromosome number were found to be 2n=24 and x=12, respectively. Except for S. chlorifolia and S. doganii, the karyomorphology of the taxa studied is here described for the first time. S. laxa was found to have the smallest chromosomes whereas the largest ones were observed in S. haradjianii. Silene chlorifolia had the highest A₁ index and S. bupleuroides subsp. bupleuroides had the highest interchromosomal asymmetry coefficient (A₂).     

The mode of action of the plant antimicrobial peptide MiAMP1 differs from that of its structural homologue, the yeast killer toxin WmKT

The plant antimicrobial peptide MiAMP1 from Macadamia integrifolia and the yeast killer toxin peptide WmKT from Williopsis mrakii are structural homologues. Comparative studies of yeast mutants were performed to test their sensitivity to these two antimicrobial peptides. No differences in susceptibility to MiAMP1 were detected between wild-type and several WmKT-resistant mutant yeast strains. A yeast mutant MT1, resistant to MiAMP1 but unaffected in its susceptibility to plant defensins and hydrogen peroxide, also did not show enhanced tolerance towards WmKT. It is therefore probable that the Greek key beta-barrel structure shared by MiAMP1 and WmKT provides a robust structural framework ensuring stability for the two proteins but that the specific action of the peptides depends on other motifs.     

A biosensor based on catalase for determination of highly toxic chemical azide in fruit juices

In this work, an amperometric biosensor based on catalase enzyme was developed for the determination of azide. The principle of the measurements was based on the determination of the decrease in the differentiation of oxygen level which had been caused by the inhibition of catalase in the bioactive layer of the biosensor by azide. Firstly, the optimum conditions for the inhibitor biosensor were established. In the optimization studies of the biosensor, the most suitable catalase and gelatin amounts and glutaraldehyde ratio were determined. Optimum catalase activity, optimum gelatin amount and glutaraldehyde percentage were 5000 Ucm(-2), 5.94 mgcm(-2) and 2.5%, respectively. Characterization studies of the biosensor such as optimum pH and optimum temperature were carried out. The repeatability experiments were done and the average value (x), standard deviation (S.D.) and variation coefficient (C.V.) were calculated as 98.6 microM, +/-4.16 microM and 4.23%, respectively. A good linear relationship with a correlation coefficient of 0.9902 was obtained over the concentration range of 25 microM to 300 microM azide. After the optimization and characterization studies the proposed biosensor was applied to the determination of azide in certain fruit juices.     

Fine needle aspiration biopsy of the parotid gland. Diagnostic problems and 2 uncommon cases

OBJECTIVE: To describe the diagnostic problems and present our findings in 2 uncommon tumors, malignant myoepithelioma and small cell undifferentiated carcinoma, by examining fine needle aspiration (FNA) biopsies of parotid gland masses. STUDY DESIGN: The study group consisted of 34 females and 41 males 12-80 years old, with an average of 44. Excluding inflammatory results, all adequate aspirates were confirmed histologically to determine the correlation. RESULTS: Sensitivity of FNA cytology was 91%, with specificity of 98%. We encountered some difficulties, and therefore misdiagnoses, in evaluating specific neoplasms, such as adenoid cystic carcinoma and Warthin's tumor, which have well-established cytologic diagnostic criteria. Two cases of uncommon neoplasms of salivary glands, small cell undifferentiated carcinoma and malignant myoepithelioma, were cytologically found to be malignant but not further classified. In addition, tuberculous parotitis, with its well-defined features, should to be referred since unnecessary surgery can be avoided by using FNA cytology. CONCLUSION: FNA is a sensitive and specific diagnostic tool for parotid gland masses. However, specific classification of neoplasms may sometimes be difficult. Pathologists should be aware of specific entities, such as malignant myoepithelioma, when evaluating high grade neoplasms.     

Detection of cell surface ligands for the gamma delta TCR using soluble TCRs

The natural ligands recognized by gammadelta TCRs are still largely unknown, in part because immunization does not normally result in Ag-specific gammadelta T cell responses. Taking advantage of an established ligand for a particular gammadelta TCR, we demonstrated that a multimerized recombinant form of this gammadelta TCR can be used like a mAb to specifically detect its own ligand. Using the same approach for more common gammadelta TCRs whose ligands remain unknown, we detected on certain cell lines molecules that appear to be ligands for three additional gammadelta TCRs. One of these represents the mouse Vgamma6/Vdelta1 invariant gammadelta TCR, which predominates in the female reproductive tract, the tongue, and the lung, and other tissues during inflammation. The second represents the closely related Vgamma5/Vdelta1 invariant gammadelta TCR expressed by most epidermal T cells. The third is a Vgamma1/Vdelta6.3 TCR, representative of a variable type frequently found on lymphoid gammadelta T cells. We found evidence that ligands for multiple gammadelta TCRs may be simultaneously expressed on a single cell line, and that at least some of the putative ligands are protease sensitive. This study suggests that soluble versions of gammadelta TCRs can be as tools to identify and characterize the natural ligands of gammadelta T cells.