Study of properties of structural subunits of IgM immunoglobulin obtained by reduction with 2-mercaptoethanol or by oxidative sulphitolysis

IgM was isolated from pig serum by isoelectric precipitation and gel filtration. Different methods of breaking down the disulphide bonds and of isolating subunits of the IgM molecule—oxidative sulphitolysis and reduction by 0.1m 2-mercaptoethanol in the absence of a disaggregating agent, oxidative sulphitolysis in the presence of 6m urea and reduction by 0.3m 2-mercaptoethanol in medium containing 6m and 8m urea—were compared. Degraded material was separated by gel filtration on Sephadex G-100 or G-200 in 0.05m formic acid with 6m or 8m urea. Oxidative sulphitolysis or reduction by 0.1m 2-mercaptoethanol without a disaggregating agent did not yield pure H andl chains. Oxidative sulphitolysis was the more effective. Oxidative sulphitolysis in 6m urea medium severely damaged the material. Reduction of IgM by 0.3m 2-mercaptoethanol in 6m or 8m urea also altered its immunochemical properties. The possible presence of light chains in the heavy chain fraction cannot likewise be excluded in this case. The results are in agreement with experiments showing that the molecular weight of the IgM heavy chain is greater than that of the IgG heavy chain.     

Some properties of pea enation mosaic virus isolated from field pea and broad bean plants in Bohemia

Pea enation mosaic virus (PEMV) was isolated from disea sed field pea (Pisum sativum L.ssp. arvense A.Gr.) and broad bean (Faba vulgaris Moench) plants grown as filed crops at Bohumilice in Bohemia. The virus proved to be pathogenic for the following plant species:Pisum sativum L. cv. Raman,Faba vulgaris Moench,Lens culinaris Med.,Vicia sativa L.,Lathyrus odoratus L.,Glycine soja L.,Phaseolus vulgaris L.,Chenopodium amaranticolor Coste andReyn,Nicotiana clevelandi Gray,Trifolium incarnatum L. The dilution end point of the isolate was higher in pea plants (10^?4) than in broad bean plants (10^?2). The thermal inactivation point was 65–68° and the longevityin vitro between 10 and 14 days. According to the host range, symptoms on pea plants and physical properties the virus isolate studied resembles some isolates described in the U.S.A. and represents a PEMV strain different from those reported so far in Czechoslovakia.     

Underground dry weight in the grassland communities ofArrhenatheretum elatioris alopecuretosum pratensis R. Tx. 1937 andMesobrometum erecti stipetosum Vicherek 1960

The meadow plant communities,Arrhenatheretum elatioris alopecuretosum pratensis R. Tx. 1937 andMesobrometum erecti stipetosum Vicherek 1960, were chosen for investigations of the underground plant parts. Apparent differences in underground dry weight and its seasonal changes in both the communities were observed. Differences in the soil environment in different periods of the year are reflected in the character of time changes in underground dry weight. The soil environment affects not only the total underground biomass and their changes in time, but also the activity of soil microflora and, consequently, the decomposition rate of dead underground plant parts.     

Antibacterially active substances

Synthesis of two hydroxy-derivatives of nalidixic acid as a result of microbial transformation was demonstrated in certain species of the genusAspergillus. Aspergillus alliaceus produced 7-hydroxy-nalidixic acid andAspergillus niger 6-hydroxy-nalidixic acid. It was demonstrated that the antibacterial activity of both hydroxy-derivatives (tested inEscherichia coli) was lower than that of the initial nalidixis acid.     

Physiological properties of microbial population as a basis for graphical solution of multi-stage continuous cultivations

A proposal for a graphical solution of the design of a multi-stage continuous culture system is presented. The holding times in individual stages are derived from the reciprocal values of the growth rate and of the product formation rate and plotted against the cell and product concentrations. Characteristic changes of physiologically significant paramaters are then projected on these production curves. Dedicated to Academican Ivan Málek on the occasion of his 60th birthday     

Aspergilosis En Colombia

Resumen Se presentan 15 casos de aspergilosis recolectados en diferentes ciudades del país. Doce fueron casos autopsiados. Los tres restantes se refieren a pacientes en quienes se efectuó una lobectomía pulmonar superior derecha por aspergiloma gigante intracavitario. En los doce primeros existía una enfermedad básica que había alterado seriamente el estado general del paciente; once de ellos habían recibido antibióticos, cinco habían recibido esteroides, y dos, agentes citotóxicos. Se cree que, tanto el estado general del paciente, como la administración de dichas drogas, favorecieron la infección micótica. De los tres casos con aspergiloma intracavitario gigante, se cree que, en uno, la micosis se implantó en una caverna tuberculosa cicatrizada. En los otros dos, la cavidad era un bronquio localmente dilatado y se consideró que no existía una infección tuberculosa.ElAspergillus posee un amplio espectro de patogenicidad. Se le puede observar en lesiones que van desde una localización intrabronquial, acompañada de mínima o nula reacción inflamatoria, hasta casos en los cuales existen lesiones pulmonares necrotizantes con diseminación hematógena a otros órganos (sistema nervioso central, hígado, riñón).     

Use of Carbowax as a high molecular weight nonprotein substance for cultivation of lymphoid cell and study of their morphology

Lymphoid cells prepared from rabbit popliteal lymph nodes were cultivated in medium in which the high molecular weight component was replaced by Carbowax 20 M. This substance, in 0.2% concentration, proved to be a substitute for the high molecular weight component in short-term cultivation, and the viability results were similar to those in medium containing normal rabbit serum or 0.5% human serum albumin. In addition, mitoses and the formation of large basophilic cells resembling the blastoid cells induced during cultivation with phytohaemagglutinin were observed in this medium. The results are discussed.     

Secondary responsein vitro to antigen ΦX 174 phage

In a model secondary reactionin vitro, a correlation was demonstrated between the size of the antigen dose used for the prestimulation of spleen tissue donors and the type of antibodies formed in the anamnestic reaction. After a small dose of antigen ΦX 174, the antibody response three days after prestimulation was of the 19 S (IgM) type, but later secondary contactin vitro (after four months) did not produce a 19 S anamnestic reaction. After large primary doses of antigen, a short interval between primary and secondary contact led to the formation of 19 and 7 S type antibodies, while after a long interval only 7 S (IgG) type antibodies were formed. The results are discussed in relation to differences in the size of the antigen dose needed to induce short-term 19 S and long-term 7 S immunological memory.