Sequence homology: A poor predictive value for profilins cross-reactivity

Background

The basophil activation test (BAT), in which translocation of markers to the surface of blood basophils is measured in response to allergen by flow cytometry, is a rapid assay that is gaining popularity. Two markers are currently being evaluated for the BAT; CD63 and the lineage-specific CD203c. In a recent report, detection of CD203c after lysis with Saponin was shown to be superior to detection of CD63 after lysis with formic acid. We wanted to compare a) lysis with formic acid and lysis with Saponin, b) the response through CD203c and CD63, and c) the definition 10% activated cells above background with the probability binning metric T(χ) > 4, on sets of data generated with blood basophils stimulated with varying concentrations of anti-FcεRI antibody.

Methods

Blood from volunteers was incubated with serial logarithmic dilutions of anti-FcεRI and subsequently with antibodies to CD203c PE and CD63 FITC. Sets of samples set up in parallel were lysed with either Saponin based Whole Blood Lysing reagent or with formic acid based Immunoprep/Q-prep. Samples were acquired on a FACS Calibur, but were compensated and analysed offline. Responders were defined as persons who had 10% or more activated basophils above background, or a T(χ) > 4, for two consecutive dilutions of anti-FcεRI antibody.

Results

More basophils (median 1164 vs. median 397) and better discrimination of upregulated CD203c and CD63 amongst responders were obtained after lysis with Saponin than after lysis with formic acid. We suggest that CD203c may be a more sensitive marker for the BAT than CD63, as 6/11 responders were found with CD203c, compared with 3/11 with CD63. Most responders (7/11) were identified with probability binning.

Conclusion

A combination of lysis with Saponin and the markers CD203c and CD63 computed by probability binning may be the most sensitive method of detecting activation of basophils after stimulation through FcεRI.     

Temperature-dependent protection against Ichthyophthirius multifiliis following immunisation of rainbow trout using live theronts

Rainbow trout Oncorhynchus mykiss Walbaum, 1792 fingerlings were vaccinated by intraperitoneal (i.p.) injection using live theronts of the skin parasitic ciliate Ichthyophthirius multifiliis Fouquet, 1876 at 2 temperatures (12 and 20 degrees C), and protection against challenge infections was subsequently evaluated by bath exposure to live theronts. Vaccination conferred a relative protection (evaluated as the decrease in the number of established theronts) at 12 degrees C and almost complete immunity at 20 degrees C. Significantly increased immobilisation titers (using plasma immobilisation of live theronts) were found in immunised fish at Week 2 and 4 post-vaccination. Lysozyme activity of plasma from vaccinated fish increased from Week 1 to 4. Both immobilisation titers and lysozyme activity were significantly higher at 20 degrees C. This study demonstrated that live theronts are good candidates for an antigen source for development of effective vaccines against white spot disease in this fish host, and further indicated that the protection of rainbow trout against I. multifiliis infection is highly temperature dependent and may be associated with both adaptive and innate response mechanisms.     

Heterologous virus-induced gene silencing as a promising approach in plant functional genomics

VIGS (virus induced gene silencing) is considered as a powerful genomics tool for characterizing the function of genes in a few closely related plant species. The investigations have been carried out mainly in order to test if a pre-existing VIGS vector can serve as an efficient tool for gene silencing in a diverse array of plant species. Another route of investigation has been the constructing of new viral vectors to act in their hosts. Our approach was the creation of a heterologous system in which silencing of endogenous genes was achieved by sequences isolated from evolutionary remote species. In this study, we showed that a TRV-based vector cloned with sequences from a gymnosperm, Taxus baccata L. silenced the endogenous phytoene desaturase in an angiosperm, N. benthamiana. Our results showed that inserts of between 390 and 724 bp isolated from a conserved fragment of the Taxus PDS led to silencing of its homolog in tobacco. The real time analysis indicated that the expression of PDS was reduced 2.1- to 4.0-fold in pTRV-TbPDS infected plants compared with buffer treated plants. Once the best insert is identified and the conditions are optimized for heterologous silencing by pTRV-TbPDS in tobacco, then we can test if TRV can serve as an efficient silencing vector in Taxus. This strategy could also be used to silence a diverse array of genes from a wide range of species which have no VIGS protocol. The results also showed that plants silenced heterologously by the VIGS system a minimally affected with respect to plant growth which may be ideal for studying the genes that their complete loss of function may lead to decrease of plant growth or plant death.     

Molecular analysis of species of Tulipa L. from Iran based on ISSR markers

Molecular characterization of Tulipa L. species can elucidate the relationships among the species and provide more information about the taxonomy of this valuable genus. In this study, the genetic relationship among 39 Tulipa accessions from Khorassan and Yazd Provinces, located in east and northeast Iran, were analyzed using inter-simple sequence repeat (ISSR) primers. Ten selected ISSR primers from 20 screened primers generated a total of 97 polymorphic DNA bands. Unweighted pair-group method of cluster analysis based on Dice similarity values separated the accessions into nine groups. Seven species were recognized within these groups, and T.?micheliana Hoog was the most frequently encountered species. The subgroups formed within both T.?micheliana and T.?lehmanniana Merckl. revealed a low level of diversity within these species. T.?biebersteiniana Schultes & Schultes fil. and T.?biflora Pallas accessions made a separate clusters. The grouping of accessions was generally consistent with principal coordinate analysis (PCA) and clearly showed the position of species in the subgenera and sections of Tulipa. These results clearly showed the usefulness of DNA fingerprinting for identification of Tulipa accessions, and it is imperative to collect and characterize more genetic variability from the other distribution areas of this genus.     

Electron microscopic study of mouse embryonic stem cell-derived cardiomyocytes

Differentiation of embryonic stem cell (ESC)-derived embryoid bodies (EBs) is a heterogeneous process. ESCs can differentiate in vitro into different cell types including beating cardiomyocytes. The main aim of the present study was to develop an improved preparation method for scanning electron microscopic study of ESC-derived cardiac bundles and to investigate the fine structural characteristics of mouse ESCs-derived cardiomyocytes using electron microscopy. The mouse ESCs differentiation was induced by EBs’ development through hanging drop, suspension and plating stages. Cardiomyocytes appeared in the EBs’ outgrowth as beating clusters that grew in size and formed thick branching bundles gradually. Cardiac bundles showed cross striation even when they were observed under an inverted microscope. They showed a positive immunostaining for cardiac troponin I and α-actinin. Transmission and scanning electron microscopy (TEM & SEM) were used to study the structural characteristics of ESC-derived cardiomyocytes. Three weeks after plating, differentiated EBs showed a superficial layer of compact fibrous ECM that made detailed observation of cardiac bundles impossible. We tried several preparation methods to remove unwanted cells and fibers, and finally we revealed the branching bundles of cardiomyocytes. In TEM study, most cardiomyocytes showed parallel arrays of myofibrils with a mature sarcomeric organization marked by H-bands, M-lines and numerous T-tubules. Cardiomyocytes were connected to each other by intercalated discs composed of numerous gap junctions and fascia adherences.     

Cloning and expression of cyclophilin from Platanus orientalis pollens in Escherichia coli

Background:

Allergy is a clinical disorder affecting the human population with wide geographical distribution. Platanus orientalis (P. orientalis) trees are planted in many countries and their pollen causes allergic reactions.Cyclophilin has recently been identified as one of the most important allergens of P. orientalis pollen. We aimed to clone and purify this allergen in Escherichia coli for further studies and therapeutic and diagnostic purposes for allergy to P. orientalis.

Methods:

RNA was extracted from P. orientalis. A full-length fragment encoding cyclophilin was prepared by polymerase chain reaction amplification of the first-strand cDNA synthesized from P. orientalis RNA. The cDNA was inserted into the pET32b (+) vector, and the construct transformed into E. coli Top10 and BL21 cells. The expressed protein was purified by the CuSO4 method.

Results:

The cDNA for the cyclophilin of P. orientalis pollen was cloned, and a specific reactivity of recombinant cyclophin was confirmed by immunoblotting using sera from patients allergic to P. orientalis pollen.

Conclusion:

The recombinant cyclophilin has a potential for immunologic assays for evaluation of allergy to P. orientalis pollen.Key Words: Allergy; Recombinant allergen; Cyclophilin, Escherichia coli, Platanus orientalis, Pollen, Cloning     

Ultrastructural changes of sheep cumulus-oocyte complexes following different methods of vitrification

To determine the ultrastructural changes of sheep cumulus-oocyte complexes (COCs) following different methods of vitrification, good quality isolated COCs (GV stage) were randomly divided into the non-vitrified control, conventional straw, cryotop and solid surface vitrification groups. In both conventional and cryotop methods, vitrified COCs were respectively loaded by conventional straws and cryotops, and then plunged directly into liquid nitrogen (LN2); whereas in the solid surface group, vitrified COCs were first loaded by cryotops and then cooled before plunging into LN2. Post-warming survivability and ultrastructural changes of healthy COCs in the cryotop group especially in comparison with the conventional group revealed better viability rate and good preservation of the ooplasm organization. However in all vitrification groups except the cryotop group, mitochondria were clumped. Solely in the conventional straw group, the mitochondria showed different densities and were extremely distended. Moreover in the latter group, plenty of large irregular connected vesicles in the ooplasm were observed and in some parts their membrane ruptured. Also, in the conventional and solid surface vitrification groups, cumulus cells projections became retracted from the zona pellucida in some parts. In conclusion, the cryotop vitrification method as compared with other methods seems to have a good post-warming survivability and shows less deleterious effects on the ultrastructure of healthy vitrified-warmed sheep COCs.     

Bioconversion of Hydrocortisone by Cyanobacterium Fischerella ambigua PTCC 1635

Summary The bioconversion of hydrocortisone by a locally isolated strain of cyanobacterium Fischerella ambigua PTCC 1635 was investigated. Fischerella ambigua had not been previously examined for this potential. The fermentation led to production of 11β,17α, 20β, 21-tetrahydroxypregn-4-en-3-one and 11β-hydroxyandrost-4-en-3,17-dione. The metabolites were isolated and purified by chromatographic methods and identified using instrumental analyses.