Biosynthesis of ascorbic acid and mobilization pattern of macromolecules during water stress in germinating cicer seedlings

Ascorbic acid (AA) turnover, and levels of RNA and protein were determined during germination ofCicer arietinum cv. Chafa under—(i) normal watering; (ii) water stress of six days; and (iii) revival upto next stage of seedling growth after water stress. Water stress lowered significantly AA, ascorbigen, ascorbic acid—macromolecule complex, RNA and protein content in embryo axis while a reverse trend was seen after revival. In the cotyledon, AA, RNA and protein contents were higher during water stress. However on revival only AA and protein contents decreased, whereas the RNA content showed further enhancement. It is suggested that increased synthesis of AA in the cotyledon during water stress may trigger enhanced synthesis of RNA and consequently of enzymic proteins, thus bringing about rapid mobilization of reserve materials during revival.     

Paramagnetic behaviour of the differentiating reproductive apex of wheat

Summary A study of the physiological significance of EPR signal was undertaken in the developing apical organs as well as in the top most leaf of a determinate type of plant,Triticum aestivum Cv. S 227 at various stages of vegetative and reproductive differentiation. Pour types of signals are reported: (a) a weak asymmetrical signal having 700 Gauss of width and g=2, the origin of which, is not clear; (b) a broad six peak signal also having g=2 which, as available evidence suggests, may be due to Mn⁺⁺; (c) in association with Mn⁺⁺ signal there are also other signals caused either by paramagnetic metals or by organic free radicals (FR); (d) at the centre of Mn⁺⁺ signal there appears a free radical signal with g=2.0023. It is observed that the amplitude of Mn⁺⁺ and free radical signal increases sharply in the shoot apex during its transformation from vegetative to reproductive state. The leaf also consistently records higher Mn⁺⁺ and FR contents at all stages of reproductive differentiation. Synchronously with the above mentioned enhanced paramagnetic behaviour of the apex and of the leaf there is an upsurge in metabolic activity of the plant. The possible role of free radicals and Mn⁺⁺ in energy transfer is discussed in relation to ascorbic acid turnover.     

Loss of phylogenetic information in chorion gene families of Bombyx mori gene conversion

The silkmoth chorion has provided a stimulating model for the study of evolution and developmental regulation of gene families. Previous attempts at inferring relationships among chorion sequences have been based on pairwise comparisons of overall similarity, a potentially problematic approach. To remedy this, we identified the alignable regions of low sequence variability and then analyzed this restricted database by parsimony and neighbor-joining methods. At the deepest level, the chorion sequence tree is split into two branches, called "alpha" and "beta." Within each branch, early- and late-expressing genes each constitute monophyletic groups, while the situation with middle-expressing genes remains uncertain. The HcB gene family appears to be the most basal beta-branch group, but this conclusion is qualified because the effect of gene conversion on branching order is unknown. Previous studies by Eickbush and colleagues have strongly suggested that ErA, HcA, and HcB families undergo gene conversion within a gene family, whereas the ErB family does not. The occurrence of conversion correlates with a particular tree structure; namely, branch lengths are much greater at the base of the family than at higher internodes and terminal branches. These observations raise the possibility that chorion gene families are defined by gene conversion events (reticulate evolution) rather than by descent with modification (synapomorphy).      

Cytomorphologic patterns in papillary cystic variant of acinic cell carcinoma of the salivary gland

OBJECTIVE: To study the cytomorphologic profile of the papillary and cystic variant of acinic cell carcinoma (ACC-PCV) of the salivary glands. STUDY DESIGN: We studied 6 aspirates from 5 cases of ACC-PCV. RESULTS: All the cases had varied cytomorphologic features depending upon the degree of vacuolation of cells. However, common to all was a papillary pattern and a cystic fluid background with or without mucin blobs; that led to misdiagnosing the tumor as mucoepidermoid carcinoma on 2 occasions. The smears showed papillary fragments, sheets or clusters of vacuolated/histiocyte like cells and granular cells. The histiocytelike cells resembled macrophages, with finely vacuolated cytoplasm and an eccentrically placed nucleus with frequent binucleation. Vascular cores were seen in a few aspirates. The granular cells were similar to those seen in the usual acinic cell carcinoma but were smaller. The tumor did not show any acinar pattern and lacked naked nuclei in the background. In 4 aspirates finely distributed, brown hemosiderin pigment was detected in the vacuolated cells. CONCLUSION: ACC-PCV is papillary and cystic and hence is often not recognized as acinic cell carcinoma. However, papillary fragments of vacuolated cells or histiocytelike cells and granular cells are clues to the diagnosis.     

Recent advances in the immunogenetics of idiopathic inflammatory myopathy

This review summarizes the previous and current literature on the immunogenetics of idiopathic inflammatory myopathy (IIM) and updates the research progress that has been made over the past decade. A substantial part of the genetic risk for developing adult- and juvenile-onset IIM lies within the major histocompatibility complex (MHC), and a tight relationship exists between individual human leukocyte antigen alleles and specific serological subtypes, which in turn dictate clinical disease phenotypes. Multiple genetic regions outside of the MHC are increasingly being identified in conferring IIM disease susceptibility. We are still challenged with the task of studying a serologically and clinically heterogeneous disorder that is rarer by orders of magnitude than the likes of rheumatoid arthritis. An ongoing and internationally coordinated IIM genome-wide association study may provide further insights into IIM immunogenetics.     

Retroperitoneal mesenchymal chondrosarcoma. Report of a case diagnosed by fine needle aspiration cytology

An unusual case of retroperitoneal mesenchymal chondrosarcoma diagnosed by fine needle aspiration (FNA) biopsy is described. CT-guided FNA of a mass arising in retroperitoneal soft tissues yielded an amorphous, myxoid material containing two distinct and separate populations of tumor cells. One was an undifferentiated, monomorphic, small cell component with granular cytoplasm and round central nuclei. The second population was an overtly malignant chondroid component scattered within an abundant myxoid matrix showing foamy cytoplasm, marked nuclear pleomorphism and frequent multi-nucleation. These cytologic findings were distinctive and similar to the histologic findings. The differential diagnosis and the possible pitfalls in the FNA diagnosis of this relatively rare tumor are discussed.