Muscle Tissue Of Animals Research Articles

The Sex Chromatin of Interphase Nuclei in the Nine-Banded Armadillo <i>Dasypus novemcinctus</i>

Fixed tissues from 13 armadillos and cell cultures from two were examined for the presence of sex chromatin. Barr bodies were easily recognizable in smooth and cardiac muscle tissue of adult animals and in loose connective tissue of the embryos. Nervous tissue proved unsuitable for sexing both in young and adult armadillos. Cultured cells in vitro were also examined and showed prominent nuclear sex chromatin in the female animals. These results are in accordance with Benirschke's earlier findings in these animals.

Conformation of individual macromolecular particles from myosin solutions

Meat is the edible muscle tissue of animals. The sarcomere is the fundamental functional unit of muscle. Growth and development of muscle is accomplished by the highly ordered accretion and assembly of the constituent proteins in the sarcomere. Primary amino acid sequence elements of the constitutive proteins carry the information necessary for determining the final architecture of the sarcomere. The mechanisms by which the constitutive proteins are assembled and function together to form the sarcomere and produce muscle contraction is just now beginning to be understood. The predominant protein in the sarcomere, found in the thick filament system, is myosin. In physiological buffers purified myosin spontaneously assembles into a synthetic thick filament with a dramatic resemblance to the native thick filament. Some of the amino acid sequence elements contributing to myosin's assembly properties may also be critical to myosin's solubility function, which is so crucial to the manufacture of high quality prepared meat products. This review summarizes recent experimental results contributing to our understanding of the mechanism of sarcomeric muscle myosin assembly.

The distribution of the formate activating enzyme and other enzymes involving tetrahydrofolic acid in animal tissues

A survey of a number of animals showed that the formate activating enzyme is present in almost all tissues. In invertebrates, the largest amounts of this enzyme were found in the gonads and reproductive products and the smallest amounts were found in muscle and digestive glands, except for Cancer magister. In the few vertebrate species included in this study, the greatest amounts of formate activating enzyme were found in liver tissues. Formate activating enzymes isolated from the oöcytes of Schizobranchia insignis, from the ovaries of Pecten caurinus, Balanus nubilis and Cancer magister and from the livers of Sebastodes caurinus and the rabbit were compared with respect to the K M values for the three components of the reaction and for the requirement for divalent metal ions. Some information was also obtained on the pH optimum, the require-metal ions. Some information was also obtained on the pH optimum, the requirement for a reducing agent, and the stability of various enzyme preparations to storage in the cold. The data obtained indicate that the above enzymes are similar to highly purified preparations of formate activating enzyme obtained from bacteria, although some differences were found in the individual K M values, the metal requirements and the stability upon storage. Forty-one tissues from a selected group of animals ( Schizobranchia insignis, Nereis brandti, Pecten caurinus, Strongylocentrotus purpuratus, Balanus nubilis, Cancer magister, Sebastodes caurinus, Onchorynchus nerka, the chicken and the rabbit) were examined with respect to the amounts of four additional enzymes (N 10-formyl tetrahydrofolic acid deacylase, cyclohydrolase, hydroxymethyl tetrahydrofolic acid dehydrogenase, and serine hydroxymethylase) concerned with the synthesis and interconversion of one-carbon derivatives of folic acid. Except for muscle tissue, varying amounts of the four enzymes were found and no correlation could be found between the levels of these enzymes and that of the formate activating enzyme. The muscle tissues of the above animals contained only small quantities of formate activating enzyme, deacylase, cylohydrolase and hydrofolic acid dehydrogenase, but had fairly large amounts of serine hydroxymethylase. In addition, the above animals were tested for the presence of the formaldehyde activating enzyme. Although 29 of the 41 tissues were found to have this enzyme, no correlation could be found between its distribution and that of the other enzymes studied.

ON PARTIAL IDENTITY OF CAUSE AND EFFECT

IT appears to be an essential feature of most views of efficient causation that a causative event both begins sooner than its effect does and ends after the effect begins. And from such a standpoint, it would obviously be inconsistent to regard all of some causative event as part of its immediate effect. On the other hand, descriptions of certain common biological processes appear susceptible to an interpretation allowing for cases in which most of a cause is construed as part of its effect. The aim of this essay is to explore such an interpretation, as well as an alternative view which accommodates the same descnptive subject matter, but which rules out calling one event the cause of another immediately resulting from it whenever the two have even a single space-time part in common.' An example from the physiology of animal motion will illustrate a causal process which might be construed according to either of these interpretations. On the contemporary view, the physiological cause of a response or vital action by a higher animal is the rapid breakdown of an energy-releasing phosphorus compound, such as adenosine triphosphate (ATP), which has been formed and stored earlier m the animal's muscle tissue. After the orgamsm has been stimulated appropriately, each muscle to be used m the response is excited in such a way that some of its own store of ATP is broken down chemically, liberating energy for the contraction of the muscle. More generally, a certain chemical change inside the muscle tissue causes, or results in, its contraction. Now this latter statement deserves close attention.

Studies on the Helminth Fauna of Alaska. XXVII. The Occurrence of Larvae of Trichinella spiralis in Alaskan Mammals

An effort was made to obtain a series of each species of mammal occurring in Alaska, with exception of the ungulates. Such specimens were collected over the entire Territory, but most originated above the Arctic Circle. Many mammals were secured through the cooperation of Eskimo and Indian trappers, who held the frozen carcasses of animals taken for their fur until they could be brought to the laboratory in Anchorage. In some instances, only muscle tissue of animals, with collecting data, was preserved. The personnel of the Zoonotic Disease Section also collected large numbers of mammals. Dogs were generally obtained when those no longer serviceable were destroyed, but some were purchased for this study. Although some autopsies were performed in the field, most of the animals were brought entire to the laboratory. For the purposes of this work, several grams of striated muscle were taken, routinely from the diaphragm, at the autopsy of each animal. These samples were frozen and stored for later processing. The larvae were usually dead when isolated. The presence of Trichinella larvae was determined through the artificial digestion of tissue samples. For this purpose, the tissue was chopped with a knife into small pieces, placed in a solution of pepsin and hydrochloric acid, and incubated at 37? C. with constant agitation for 24 hours. The resulting fluid was poured through a fine-mesh screen to remove any undigested material and was allowed to stand in graduated cylinders until any larvae present settled out. The supernatant fluid was siphoned off, the residue placed in watch glasses with a few drops of 10 percent

Species Differences in Amino Acids of Culex Mosquitoes

LF ONE considers the criteria used for the determination of differences among more or less closely related plants or animals, it will be noted that, except for studies on various micro-organisms, those tests based upon comparative physiology or comparative biochemistry have not been widely used. With the introduction of techniques for the detection, with a high degree of accuracy, of minute amounts of the more complex and supposedly more specific components of the bodies of organisms, the possibilities are greatly enhanced for demonstrating biochemical differences between higher plants or animals of very similar morphology. Among the more reliable and reproducible techniques are those of microbiological assay, microelectrophoresis, and paper chromatography. Paper chromatography is particularly valuable in the determination of amino acids, since quantitative concentrations as low as a fraction of a microgram can be detected (Pratt and Auclair, 1948), while qualitative determinations can be made easily by using known amino acids as references. Insects are especially useful in amino acid determinations, since they show a particularly high concentration in their blood compared with that found in other animals (Pratt, 1950). Various workers have identified the amino acids found in insect tissues, but apparently only Micks and Ellis (1951, 1952) and Clark and Ball (1951, 1952) have attempted to compare the pictures obtained from species which are at present commonly recognized as being within a single genus. Among investigations of higher organisms, there seem to have been, previous to the work referred to above, no reports of the use of an entire plant or animal. Work using only a part of an organism, e.g., the comparison of the amino acids found in muscle tissues of different animals used as food, shows some differences, both qualitative and quantitative, between more widely separated groups and indicates in addition that the amounts and/or kinds of amino acids may vary from tissue to tissue in a single organism (Beach, Munks and Robinson, 1943; Block and Mitchell, 1946). Quantitative differences in amino acid concentration have been reported between insects of different families (Duchateau, Sarlet and Florkin, 1952) and of different genera (Micks and Ellis, 1951). And recently, in a preliminary communication, Buzzati-Traverso and Rechnitzer (1953) have noted differences in the paper chromatographic pictures from tissues of fish taken not only from different species but also from geographically separated populations of the same species. According to these authors, however, the free amino acids did not play an important role in their results. The method used in our work and in that of Micks and Ellis (1951) was designed to show the free amino acid constitution (as compared to amino acids bound in other molecules) of an entire organism. The methods of preparation of the material were described in some detail in a previous paper (Clark and Ball, 1952). In the present experiments the bodies of approximately forty starved mosquitoes were homogenized; the homogenate was deproteinized with cold ethanol and filtered. After several washings of the precipitate, the resulting filtrate, which contained the amino acids, was reduced to a

Effect of Contact with Tissues In-Vitro on Activity of a Chicken Tumor Agent.

The filtrate of Chicken Tumor No. 1 when kept in contact for 1 to 5 hours at room temperature with finely minced or dried muscle from susceptible fowl is generally either completely inactivated or has its potency greatly reduced. This partial or total inactivation was pronounced in 34 out of 46 tests. Carefully controlled experiments have shown that the 12 cases in which there was no demonstrable reduction in potency of the filtrate after muscle contact was explained by the fact that excessively active filtrates were used, for the inactivating effect of the muscle became evident when such filtrates were tested in more dilute form. The specific nature of this reaction was shown by the fact that not only did muscle tissue of such resistant animals as the rabbit and pigeon have no effect on the activity of the tumor filtrate but the brain, kidney and liver of the susceptible chicken were without activity in this respect. Desiccation of chicken muscle pulp after contact with filtrates has failed to release the tumor agent in an active form from the muscle. Either the union of the agent with the muscle substances is so strong as to render dissociation difficult or the phenomenon may be one of inactivation.