The intronless mouse gene for the tissue specific splicing protein SmN is a processed pseudogene containing a stop codon after thirty-one amino acids.

The SmN protein is a component of small ribonucleoprotein particles which is closely related to the ubiquitously expressed splicing proteins SmB and B' but is expressed in only a small number of cells and tissues. We have isolated a mouse SmN-related sequence which lacks introns and contains multiple changes from the SmN cDNA sequence including a stop codon after thirty-one amino acids which would prevent it encoding functional SmN protein. This indicates that this intronless gene is a processed pseudogene and that the functional gene has yet to be isolated. In agreement with this southern blotting of mouse DNA with SmN probes reveals bands, additional to those derived from the pseudogene, which are characteristic of an intron-containing SmN gene. The relationship of the pseudogene to the functional SmN gene and to an intronless SmN-related sequence in the rat genome is discussed.     

Liberation of protoplasts from the yeast-like form of Paracoccidioides brasiliensis by enzymatic treatment

Spherical and osmotically sensitive protoplasts were released from cultures of the yeast-like form of Paracoccidioides basilienisis strain IVIC Pb9 through the action of a mixture of crude enzyme preparations: alpha and beta-glucanases and chitinase, obtained from culture filtrates of Cladosporium resinae, Basidiomycete QM 806 and Streptomyces sp respectively. The highest efficiency of protoplast liberation was achieved when each crude enzyme preparation was used at 1 mg/ml.     

Chromosomes in Bos Taurus as Revealed by Prefixation Treatment with Hypotonic Solutions

To study chromosomes in bull testes and their behavior at meiosis, a prefixation treatment with hypotonic solutions was used. After fixation, the material was squashed and stained with Feulgen's nucleal reaction. When needed, additional staining with iron-hematoxylin was feasible. The hypotonic Tyrode solutions of 10 to 20% normal strength were prepared according to A. Hughes (1952); the time of pretreatment was, in general, 15-30 min; fixation was made in glacial acetic acid-absolute alcohol (1:3) and Feulgen squash technic was carried out according to Schedule 5 of Darlington and La Cour (1947). Morphologic details were well preserved and photomicrographs of well-spread chromosomes in one plane were obtained easily.     

Production of polysaccharides by Arthrobacter globiformis associated with Anabaena azollae in Azolla leaf cavity

Abstract The composition of the capsular polysaccharides (CPS) and exopolysaccharides (EPS) of three strains of Arthrobacter globiformis , isolated from the leaf cavities of Azolla caroliniana (strain B1), A. filiculoides (strains A3 and L1) and A. globiformis ATCC 8010 have been analysed by HPLC and enzymatic assays. Glucose and galactose were detected in the EPS of all the strains, while rhamnose was present only in the EPS of the strain L1 and uronic acids in B1 and ATCC 8010. Traces of fructose were detected by enzymatic assays in all the strains. The CPS contained glucose, galactose and rhamnose, while uronic acids were present only in strain B1. In all the strains the amount of EPS was higher than CPS. The reactivity to different dyes and lectins of the mucilagineous matrix of the algal packets extracted from the fern and of the bacterial mucilage were similar.     

Cytochemical identification of the leukocytes of torpedoes (Torpedo marmorata Risso and Torpedo ocellata Rafinisque)

The authors subjected peripheral blood smears of Torpedoes to cytochemical analysis of lipids, protein, neutral and acid polysaccahrides and of some enzymatic activities, i.e. adenosine triphosphatase (ATP-ase), acid and alkaline phosphatase, aliesterase and peroxidase. It was found that neutrophilic granulocytes are intensely PAS and aliesterase positive and weakly ATP-ase positive. Eosinophilic granulocytes show the presence of neutral polysaccharides in the matrix (which is PAS positive) and strong ATP-ase and acid phosphatase activities in the granules. Lymphocytes sometimes contain weakly PAS and aliesterase positive granules. Monocytes show some small PAS positive granules and weak acid phosphatase and aliesterase activities. Thrombocytes contain some peripheral granules which are PAS positive and slightly ATP-ase positive. There are no transitional forms between the various cellular types. The results confirm the classification of leukocytes of Torpedoes into neutrophilic granulocytes, eosinophilic granulocytes, lymphocytes, monocytes and thrombocytes and contribute some informations about the histoenzymatic content of Elasmobranch leukocytes.