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The new acidophilus liquid mixtures "Malyutka" and "Malysh" manufactured under industrial conditions were subjected to comprehensive physicochemical, microbiological and biological studies. Amino acids and fatty acids contained by the mixtures as well as their biological value were also examined.
BACKGROUND: Environments shape adaptive trajectories of populations, often leading to adaptive parallelism in identical, and divergence in different environments. However, how does the likelihood of these possibilities change with minute changes in the environment remain unclear. RESULTS: In this study, we evolved Saccharomyces cerevisiae in environments which differed only in the manner in which the sugar source is presented to the population. In one set of populations, carbon was presented as a mixture of glucose-galactose, and in the other, as melibiose, a glucose-galactose disaccharide. Since the two environments differed in how the two monosaccharides are packaged, we call these environments 'synonymous'. Our results show that even subtle environmental differences can lead to differing phenotypic responses between the two sets of evolved populations. However, despite different adaptive responses, pleiotropic effects of adaptation are largely predictable. We also show that distinct genomic targets of adaptation between the two sets of evolved populations are functionally convergent. CONCLUSION: This study highlights how subtle environmental differences dictate phenotypic and genetic adaptation of populations. Additionally, these results also suggest the predictive potential of ancestor's fitness in understanding pleiotropic responses. Our work underscores the importance of studying more such environments to understand the generality of adaptive responses in populations.
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The scotopic visual pigments of three percids from Quebec waters, viz. the yellow perch (Perca flavescens), the walleye (Stizostedion vitreum) and the sauger (S. canadense), were studied in situ using a microspectrophotometer-computer complex. The difference spectra show that the three fishes possess a porphyropsin whose lambda max. is at 530 nm in the yellow perch, 533 nm in the walleye and at 536 in the sauger. This variation corresponds to the tendency of the visual pigments to fit the preferred environments. The three species studied also have different modes of life. The yellow perch inhabits mostly shallow, clear waters while the walleye and sauger prefer turbid waters. The retinal structure and responses also differ among them. Since the difference in lambda max. is so small, the differences in habitat and behaviour may be attributed to morphological differences in the retina rather than to its visual pigment content.
A general theory which describes the existence of live organisms is introduced; this theory is the Principle of Adequate Function and it describes all the situations in which live organisms may exist, whether healthy or sick at both physiological and pathological conditions. In biology, so far, the existence of living organisms under physiological conditions is described by homeostasis, and under pathological conditions specific immunity is used. As it is shown below, adaptation and non-specific resistance provide a much broader basis of how living organisms exist under both physiological and pathological conditions. This general theory does not interfere with the notions of homeostasis, adaptation, and specific immunity but includes them as particular cases. It is proposed that the principle of adequate function supplements the description of life processes by the evolutionary principle; it describes the laws of existence and function of a particular individual.
In the U.K. contribution to the H.A. (Human Adaptibility) section of I.B.P., genetic and anthropological studies have focused on three concerns. First, attempts have been made in a number of investigation to gain additional descriptive information about the genetic compostition of the world's populations. Concentrating on blood groups, blood enzymes, serum proteins and other polmorphic markers important gaps have been filled in our knowledge of the geographical paterns of human variation and of the affinities of populations wig and characterizing populations which were being studied for other purposes. For example, it was of critical concern in interpreting results to know in the investigations of climatic physiology and nutrition in Ethiopia and Israel whether the various groups studied in different environments were genetically the same or not. Finally, attention was focused in a number of investigations, especially those in New Guinea, Tristan da Cunha, Tanzania, and the Orkneys, on the factors which determine the genetic structure of populations. In these the effects of such phenomena as inbreeding, genetic drift, founder effects, migration and gene flow and the relation between genetic variety and health were examined and much attention was given to the interaction between demographic forces and genetics.
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Age-dependent modifications of enzyme adaptations in response to a variety of environmental alterations are a biochemical expression of biological ageing. In this paper age-dependent changes of the adaptation of a number of enzymes are described. Experiments from our laboratory indicate that pyruvate kinase is more responsive to starvation and refeeding in young animals. The diminished response of pyruvate kinase in old age is caused by a decreased adaptability of the regulatory isoenzyme PK-L.
An ion exchange method for measuring concentrations of free (ionized) metal ions and its application to the determination of [Mg2+] is described. A surface sulfonated polystyrene material is used as the "twodimensional" cation exchanger. The sample-volume is 1 ml. About 50 determinations can be performed within 1 hr having a standard error of +/- (2-4)% in the optimal range of measurement. Advantages and disadvantages of the method compared with other ones are demonstrated and discussed. Free Mg2+ ion concentrations were measured in solutions containing pyrophosphate as well as haemoglobin and compared with those which were determined by equilibrium calculation or ultrafiltration.
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Progress made during the last 15 years in the studies on the relationships between mycobacteria and their bacteriophages is reviewed. The basic biology of the phages and the applications of studies on adaptation and host range are discussed in relation to the development of phage typing systems for epidemiological purposes. The nature of lysogeny, its natural occurrence, its experimental establishment, the effect of the lysogenic state on the host bacterium and the evidence that lysogenic mycobacteria are involved in human disease, especially sarcoidosis, is reviewed.
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