Histochemical studies on urate oxidase in several mammals with special reference to uricolytic ability of primates

Summary Strong reactivity for urate oxidase was found in the liver parenchymal cells of the prosimians (i.e. the tree shrew, slow loris, potto and galago) as well as those of lower mammals. The liver parenchymal cells of the platyrrhine monkeys (i.e. the marmoset, owl monkey, squirrel monkey, capuchin monkey and spider monkey) were moderately positive. There was no preferential distribution of granular reaction products in zones of liver lobules of these species. The prosimians and platyrrhine monkeys seem to be uricolytic as lower mammals are. On the other hand, the old world monkeys (i.e. Java monkey and rhesus monkey) and the apes (i.e. the orang-utan and chimpanzee) were histochemically negative.     

The distal tibia of primates with special reference to the omomyidae

The morphology of the distal tibia and its joint surfaces is described in the late Eocene European Necrolemur,the middle Eocene North American Hemiacodon,and an omomyid species from the lower part of the Bridger Formation of North America. Necrolemur,like Tarsius,exhibits tibiofibular fusion, although to a less advanced degree. The Bridger omomyids, however, show no evidence of fusion but are similar to galagos in the conformation of this joint. The distal tibia of euprimates is distinguished by several derived features. These correlate with derived features of the astragalus and are functionally related to the abduction of the foot that accompanies dorsiflexion in primates. Tarsius,omomyids, and anthropoids share a suite of features which distinguish them from strepsirhines; these maybe haplorhine synapomorphies, but the polarity of these features is difficult to determine. If they are synapomorphies, abduction accompanying dorsiflexion and movement at the inferior tibiofibular joint were restricted in ancestral haplorhines. In living primates such restriction is associated with small body size and saltatorial locomotion.     

Respiratory pathogens in non-human primates with special reference to Corynebacterium ulcerans.

An investigation of 272 non-human primates (75 Macacca cynomolgus, 97 Macacca mulatta and 100 Cercopithecus aethiops) revealed a high incidence of respiratory disease caused by Corynebacterium ulcerans, Staphylococci, Diplococci and Streptococci. Escherichia coli was also found as a secondary invader. Most of the infections occurred during winter in Macaca cynomolgus and were caused by Corynebacterium ulcerans and Diplococcus pneumoniae. The C. ulcerans strains were phage type VI G. A phage type III C strain was isolated from a Macacca mulatta. The high incidence of C. ulcerans suggests that this organism plays a significant role in the pathology of respiratory disease in the non-human primate.     

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

Both mouse and man have the common XX/XY sex chromosome mechanism. The X chromosome is of original size (5-6% of female haploid set) and the Y is one of the smallest chromosomes of the complement. But there are species, belonging to a variety of orders, with composite sex chromosomes and multiple sex chromosome systems: XX/XY1Y2 and X1X1X2X2/X1X2Y. The original X or the Y, respectively, have been translocated on to an autosome. The sex chromosomes of these species segregate regularly at meiosis; two kinds of sperm and one kind of egg are produced and the sex ratio is the normal 1:1. Individuals with deviating sex chromosome constitutions (XXY, XYY, XO or XXX) have been found in at least 16 mammalian species other than man. The phenotypic manifestations of these deviating constitutions are briefly discussed. In the dog, pig, goat and mouse exceptional XX males and in the horse XY females attract attention. Certain rodents have complicated mechanisms for sex determination: Ellobius lutescens and Tokudaia osimensis have XO males and females. Both sexes of Microtus oregoni are gonosomic mosaics (male OY/XY, female XX/XO). The wood lemming, Myopus schisticolor, the collared lemming, Dirostonyx torquatus, and perhaps also one or two species of the genus Akodon have XX and XY females and XY males. The XX, X*X and X*Y females of Myopus and Dicrostonyx are discussed in some detail. The wood lemming has proved to be a favourable natural model for studies in sex determination, because a large variety of sex chromosome aneuploids are born relatively frequently. The dosage model for sex determination is not supported by the wood lemming data. For male development, genes on both the X and the Y chromosomes are necessary.     

Histochemical characterization of cholinesterase activity in the frog brain with special reference to its localization on the wall of blood vessels

Synopsis The nature of the cholinesterase activity present on the wall of blood vessels in amphibian brain has been studied histochemically. It is concluded that the enzyme involved is acetylcholinesterase rather than butyrylcholinesterase, which more frequently occurs in the blood vessels of the brain of other vertebrates. The histochemical results are in agreement with most biochemical data concerning substrate specificity and inhibitor response for both acetylcholinesterase and butyrylcholinesterase. The two main hypotheses put forward by others in order to explain cholinesterase activity in brain vessels are discussed briefly.     

Functional morphology of the enteric nervous system with special reference to large mammals.

This short review reports the latest insights into the structural organization of the enteric nervous system, with special emphasis on the intrinsic innervation of the intestinal tract of large omnivorous mammals such as the pig. Using various techniques, including lesion experiments, morphological and neurochemical features of distinct neuronal populations as well as the direction of the axonal processes within the different nerve networks could be revealed. Special attention was paid to the considerable species differences in this respect between large omnivorous animals and humans on the one hand and small laboratory animals on the other hand.     

Comparison of arginase activity in red blood cells of lower mammals, primates, and man: evolution to high activity in primates.

Arginase activity in red blood cells (RBC) of various mammalian species including man was determined. In nonprimate species, the activity generally fell below the level of detectability of the assay: less than 1.0 mumol urea/g hemoglobin per hr. Activities in higher nonhuman primates were equal to or of the same order of magnitude as those in man (approximately 950 mumol/g hemoglobin per hr). RBC arginase deficiency with normal liver arginase activity has been shown to segregate as an autosomal codominant trait in Macaca fascicularis established and bred in captivity. This study confirms the presence of this polymorphism in wild populations trapped in several geographic areas and demonstrates the absence of immunologically cross-reactive material in the RBC of RBC arginase-deficient animals. These data when taken together suggest that the expression of arginase in RBC is the result of a regulatory alteration, has evolved under positive selective pressure, and is not an example of the vestigial persistence of an arcane function. The expression of arginase in the RBC results in a marked drop in the arginine content of these cells.     

Steroids as substrates for cholesterol: oxygen oxidoreductase, with special reference to 3beta-hydroxy bile acids.

Cholesterol: oxygen oxidoreductase [EC 1.1.3.6] from Brevibacterium sterolicum (ATCC 21387) was found to catalyze the oxidation of steroids such as sterols, steroid hormones, and bile acids having a free C-3beta hydroxyl group. However, the enzyme was inactive towards estradiol and estriol and had a weak activity towards steroids with functional groups adjacent to the 3beta-hydroxyl group on the steroid nucleus. Variation in the length of the side chain of 3beta-hydroxy steroids had no marked effect on the activity. 3beta-Hydroxy bile acids with delta4 or delta5 were oxidized to almost the same extent as cholesterol. In contrast, 3beta-hydroxy bile acids without delta4 or delta5 were oxidized only to the extent of 1.4--2.1%. 3 beta-Hydroxychol-4 or 5-enoic acid was oxidized in the same way as cholesterol. This enzyme is useful as a simple tool for identification of 3 beta-hydroxy groups of bile acids.     

Galactonolactone oxidoreductase from Trypanosoma cruzi employs a FAD cofactor for the synthesis of vitamin C

Trypanosoma cruzi, the aetiological agent of Chagas' disease, is unable to salvage vitamin C (l-ascorbate) from its environment and relies on de novo synthesis for its survival. Because humans lack the capacity to synthesize ascorbate, the trypanosomal enzymes involved in ascorbate biosynthesis are interesting targets for drug therapy. The terminal step in ascorbate biosynthesis is catalyzed by flavin-dependent aldonolactone oxidoreductases belonging to the vanillyl-alcohol oxidase (VAO) protein family. Here we studied the properties of recombinant T. cruzi galactonolactone oxidoreductase (TcGAL), refolded from inclusion bodies using a reverse micelles system. The refolded enzyme shows native-like secondary structure and is active with both l-galactono-1,4-lactone and d-arabinono-1,4-lactone. At odd with an earlier claim, TcGAL employs a non-covalently bound FAD as redox-active cofactor. Moreover, it is shown for the first time that TcGAL can use molecular oxygen as electron acceptor. This is in line with the absence of a recently identified gatekeeper residue that prevents aldonolactone oxidoreductases from plants to act as oxidases.     

Histochemical differentiation of endocrine gastrointestinal cells in test animals, with special reference to chicken embryos.

Based upon the characteristics of argent-affinity and argyrophilia and the application of specific immune histochemical methods, endocrine cells can be differentiated in the most prominent species of test animals. These methods are demonstrated in chicken embryos, because embryological studies made in order to reveal the still unknown endodermal or neuroectodermal origin of these cells are highly important.