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Anti-haemagglutinin titres and measurements of the changes in the number of antibody molecules per millilitre (A), and in their average avidities (K) were carried out by equilibrium filtration on antisera prepared in rabbits to SW, MEL and LEE influenza viruses. These studies showed: (1) Immunization of rabbits with influenza virus by the intravenous route induced sufficient levels of antibodies by the 5th day after vaccination for testing by equilibrium filtration, immunization by the intraperitoneal or subcutaneous routes did not induce sufficient antibody levels for testing by the 5th day. (2) The avidity of the antibodies present at 5 days after vaccination was higher than at 10 days after vaccination. (3) The avidity of antibodies increased during the initial response period (from the low point at 10 days) and was independent of the routes or schedules of vaccination tested. (4) Secondary vaccination did not cause a pronounced increase in the avidity of antibodies, although a few groups of rabbits showed some further increase; tertiary vaccination caused no further increase. (5) The number of antibody molecules produced in rabbits after vaccination with influenza virus depended on the route and schedule of inoculation; the routes could be ordered intravenous, intraperitoneal and subcutaneous in decreasing order of efficiency; multiple doses increased the number of antibody molecules by all routes. (6) Increases in the antihaemagglutinin levels after secondary stimulation were due mainly to increases in the number of antibody molecules. [ABSTRACT FROM AUTHOR]

A covalent bond between 4-thiouridine in position 8 and cytidine in position 13 can be quantitatively introduced in Escherichia coli tRNAfMet by irradiation at 335 nm. The cross-linked tRNAfMet can be acylated and formylated like the unmodified molecule though the rate of acylation is lower. It is bound normally to 70-S ribosomes by crude initiation factors in the presences of pAUG or T4 mRNA, and can transfer N-formyl-methionine to puromycin. Thus, the initiation process does not require any separation of the 4-thiouridine and cytidine residues. [ABSTRACT FROM AUTHOR]

Glucosyl ceramides were isolated from young mouse brains by a combination of column chromatography and thin layer chromatography. Analysis by gas-liquid chromatography-mass spectrometry of the trimethylsilyl ether derivatives revealed that about 200/0 of these compounds contained 2-hydroxy acids (mainly cerebronic acid, 2-hydroxy behenic acid, and 2-hydroxy stearic acid). The rest contained non-hydroxy acids (stearic acid was most abundant, arachidic acid, lignoceric acid and behenic acid came next). Unsaturated acids were virtually absent. The major long chain base was C18-sphingenine. Small amounts of C18-sphinganine were also present. Of interest was the finding that C20-sphingenine constituted about 20% of the total long chain bases. [ABSTRACT FROM AUTHOR]

The formation of polar, saturated C19steroids with a 3-keto-5α-configuration after incubation of 17β-hydroxyandrost-4-en-3-one (testosterone) with 105,000 × g microsomes of adult male rat liver was investigated. The metabolites were isolated by thin-layer chromatography and were identified as 2β-,6β-(tentatively), 7α-, and 16α-hydroxy-5α-dJhydrotestosterone by means of gas chromatography-mass spectrometry. The same compounds were also isolated after incubation with 2β-,6β-,7α-, and 16α-hydroxytestosterone, respectively. Incubation with 5α-dihydrotestosterone, however, resulted in the formation of 2βi-,7α-, and 16α-hydroxy-5α-dihydrotestosterone whereas no 6β-hydroxy-5α-dihydrotestosterone could be found. [ABSTRACT FROM AUTHOR]

The incorporation of [1,2-14C2]choline and methyl groups from L-[Me-14C]methionine into subfractions of phosphatidylcholines of liver and blood plasma in the rat has been studied. Fractionation by thin-layer chromatography on AgNO3-impregnated plates followed by reversed-phase partition thin-layer chromatography permitted the isolation of 8 different molecular types of phosphatidylcholines. In the liver, incorporation of [1,2-14C2]choline occurred most rapidly in palmitoyl­oleoyl and palmitoyl­linoleoyl phosphatidylcholine but was very slow in the stearoyl­arachidonoyl species. Initially, after injection of [1,2-14C2]choline, the distribution of isotope in the subfractions of different degree of unsaturation of the phosphatidylcholines in blood plasma was very similar to that of the phosphatidylcholines in the liver. Approximately 80% of the incorporated isotope was found in the mono- and dienoic fractions. After administration of L-[Me-14C]methionine the tetra and hexaenoic liver phosphatidylchotines contained 75 to 85% of the total [14C]phosphatidylcholine. The proportion of isotope in these fractions of blood plasma was lower. Among the polyunsaturated phosphatidylcholines in liver those containing palmitic and docosahexaenoic acid were found to incorporate isotope from L-[Me-14C]methionine to a greater extent than would be expected from a stoichiometric methylation of all types of phosphatidylethanolamines. The stearoyl-arachidonoyl subfraction exhibited the lowest metabolic reactivity. In both male and female rats the amounts per whole liver of the mono- and dienoic fractions were greatly reduced during fasting. [ABSTRACT FROM AUTHOR]

The presence of carotenoids in Decapoda­Orconectes limosus (Raf.) was studied. In extracts from carapace Orconectes limosus1 separated by means of column and thin-layer chromatography, the following carotenoids were identified: β­carotene, echinenone, lutein (cpoxide and ester), astaxanthin (free and ester) and one unknown xanthophyll. [ABSTRACT FROM AUTHOR]

The localized hemolysis in gel (LHG or plaque) assay has been investigated and it has been shown that the best condition for the assay is a plate made up from, a standard tissue culture medium (199) in an agarose gel. Several convenient but sub-optimal alternatives are described. Other variables that were investigated were the concentration of indicator erythrocytes in the assay plate, the amount of complement added, the incubation time and the neutralization of xenogeneic developing serum by free mouse serum γ-globulins. The reasons for using log(x+1) transformed data for statistical analysis are also presented. [ABSTRACT FROM AUTHOR]

Monkey erythrocytes infected with schizonts of Plasmodium knowlesi are agglutinated when mixed with serum taken from chronically infected monkeys (Eaton, 1938). This reaction has proved highly specific and capable of distinguishing antigenic variants of one strain. Chronic infections of P. knowlesi in rhesus monkeys are maintained by a succession of antigenically distinct populations, each population stimulating a specific agglutinin response. Additional agglutinins which are not variant specific are found at low titre in sera taken after an infection has persisted for a month or more. The possible relevance of these observations to protective immunity is discussed. [ABSTRACT FROM AUTHOR]

The distribution of rabbit anti-lymphocyte globulin (IgG) following injection into rats and mice has been studied by immunofluorescence and 131I labelling, and the tissues from treated animals have been examined by electron-microscopy. The results suggest that the anti-lymphocyte globulin reacts primarily with circulating lymphocytes, and that it penetrates the thymus, spleen and lymph nodes to a limited extent. These findings may explain the selective immunosuppressive action of anti-lymphocyte globulin. [ABSTRACT FROM AUTHOR]

Serum samples taken from rabbits 5 days after vaccination with SW influenza virus by the intravenous route contained high levels of IgM antibodies. IgG antibodies were either not detected or were present at very low levels. By the 10th day after vaccination both IgM and IgG antibodies were present in the serum. The early IgM antibodies were of high avidity while the early IgG antibodies were of very low avidity. The presence of low avidity IgG antibodies in whole serum caused a decrease in the average avidity of the antibodies in whole serum from the 5th to the 10th day post vaccination. The avidity of the IgM antibodies remained fairly constant for the first 20 days of the immune response but a slight increase was detected after secondary vaccination. The avidity of the early IgG antibodies increased during the test period of 20 days. The early IgM and IgG antibodies were heterogeneous with respect to avidity. The highly avid IgM antibodies showed high cross-reactivity with related influenza viruses, i.e. they were of low specificity. The early IgG antibodies that were of low avidity cross-reacted with only one other influenza virus out of the four tested, i.e. they were more specific; as the avidity of the IgG antibodies increased so did their cross-reactivity. [ABSTRACT FROM AUTHOR]

The article presents a study on the use and evaluation of selected industry-sponsored publications for teaching contemporary biology. A series of investigations was conducted to examine the potential of selected industry-sponsored learning aids for increasing levels of knowledge about specific aspects of contemporary biology in various academic groups. The investigations were undertaken for the following objectives: (1) to determine levels of knowledge relating to certain contemporary notions about molecular and cellular biology among various academic groups, and (2) to determine the relative effectiveness of various methods of utilizing industry-sponsored publications to extend knowledge and concepts about biology at the molecular and cellular levels in general education science courses for non-science majors, or in science education courses for prospective and in-service teachers.

Proteins of hypocotyls of bean were studied by electrophoresis. Proteins were extracted from hypocotyl segments of various stages of development starting with the relatively undifferentiated hook regions and proceeding by 2 cm segments down the hypocotyl. The proteins were the soluble (pH 7.4), the basic nuclear (histones), acidic ribonuclear and acidic chromosomal. Soluble proteins reflected differentiation of the hypocotyl in that lower hypocotyl segments had more different protein types than did the hook region. Indoleacetic acid (IAA) at 10-6 M when applied to the lower hypocotyl appeared to induce still more different proteins. However, at 10-3 M, IAA appeared to induce molecular dedifferentiation in that hypocotyl protein patterns began to resemble those of the hook. Histones also reflected differentiation, the hook having more histone types than the lower hypocotyl. IAA had no effect on histones. The hook region had two types of acidic chromosomal proteins, the lower hypocotyl one. When lower hypocotyl segments were incubated in 10-3 M IAA, the protein pattern resembled that of the hook in that the second protein normally present in the hook and not in the hypocotyl was in fact induced in the hypocotyl. The hook had two acidic ribonuclear proteins, the lower hypocotyl one. IAA did not affect this protein. These experiments suggest that IAA in some manner regulates molecular (protein) differentiation. It is further suggested that IAA accomplishes this control through the acidic nuclear proteins which are closely associated with genetic material and which reflect differentiation and are also affected by IAA. [ABSTRACT FROM AUTHOR]

The article presents information on essential metal requirements of oscillatoria phosphorylase. The necessity for a divalent metal ion for oscillatoria phosphorylase action has been reported previously. The chelate nature of this phospliorylase-metal bond was previously explored. However, because exhaustive dialysis of this algal phosphorylase did not significantly affect its activity in synthesizing polyglucoside from substrates of glticose-l-phosphate, it was not possible until now, to obtain a suitable preparation of this enzyme with which to study its specific metal ion requirements.