The complexity of living bodies and the structure of biological theories

It has been suggested that biological theories differ from physical theories because the subject matter of biology differs from the subject matter of physics especially in the fact that living bodies are more complex than nonliving bodies. It is shown that the interactional complexity of living bodies can only be expressed by invoking biological theories. The claim that living bodies are complex is, therefore, ultimately a claim about the nature of scientific theories rather than a claim about the nature of the subject matter of biology resting upon a presystematic judgement.     

Cytoplasmic particles in Tropaeolum majus

Summary Solitary (S) bodies were present in the cytoplasm of the cells of many cultivars of Tropaeolum majus. However, cultivars have also been found which completely lack these S bodies. The S bodies occur in all cells of all kinds of tissues and organs of the plant. In the anthers they occur in the cells of the endothecium tissue as well as in the tapetum layer, and even in the pollen cells. The shape of the S bodies is nearly spherical (diameter ca. 60 nm) with a tail-like appendage with a length of ca. 90–150 nm and a diameter of ca. 16 nm. The nature of the S bodies is unknown. Transmission studies by mechanical inoculation and by grafting gave no indications of a virus nature of these bodies. Reciprocal crosses between plants containing and lacking these S bodies showed that the bodies were transmitted to the progeny only if they occur in the mother plant, that is, indicated a cytoplasmic inheritance.     

Light and electron microscopic studies of intramitochondrial bodies in bovine adrenocortical cells by proteolytic digestion

Summary The nature of the intramitochondrial bodies in bovine adrenocortical cells was investigated both light and electron microscopically, by applying enzymatic digestion on paraffin and epon sections. The result that these bodies were extracted completely either by pepsin or by trypsin strengthened the validity of the previous conclusion that their nature is proteinaceous.This work was supported by a Scientific Research Grant, No. 144017, from the Ministry of Education of Japan to Prof. M. Yasuda     

THE ORIGIN OF PROTEIN AND FATTY YOLK IN RANA PIPIENS : II. Electron Microscopical and Cytochemical Observations of Young and Mature Oocytes

Electron microscope studies of young oocytes have demonstrated that the plate-like, hexagonally shaped yolk bodies previously observed in living cells are wholly within the substance of oocyte mitochondria and that they remain within these mitochondria while increasing in size. These bodies possess a crystalline structure consisting of what appear to be lines, with a spacing of 70 to 85 A, and appear very dense in the electron microscope. After formalin fixation such bodies give an intense positive test for protein, and when viewed in the electron microscope are only slightly less dense than after OsO₄ fixation. Evidence is presented for the origin of these crystals within a single crista. The clusters of yolk globules previously studied in living cells are seen to consist of several types of bodies, but an irregular dense droplet predominates. This dense material is apparently secreted by small spherical bodies which, the evidence suggests, originate from the breaking up of filamentous mitochondria and which possess an outer double membrane and sometimes internal cristalike membranes. When thin sections of young oocytes are immersed in xylol the dense globules of the clusters are dissolved, but the hexagonal bodies are unaffected, indicating that the globules are of a predominantly fatty nature, while the hexagonal bodies are of a predominantly protein nature. Examination of mature or almost mature oocytes has revealed that the main body of the yolk platelets is crystalline in nature and is surrounded by a thick matrix which, in light microscope study, masks the fact that the face view of the main body of the platelets is often hexagonal. The spacing within the main body is found to be 70 to 85 A. The crystal laminae of this material can be resolved quite clearly into rows of particles. Dense globules of varying sizes are found in the cytoplasm between the platelets. When thin sections of these OsO₄-fixed oocytes are immersed in xylol, the material of the globules is extracted and the crystalline material of the platelets remains unaffected, indicating the fatty nature of the globules and the protein nature of the platelets. The platelets of the mature egg resemble the hexagon bodies, previously described in young oocytes, in their protein nature, their crystalline spacing, and their hexagonal outline. This is given as strong evidence for the origin of the mature platelets by the growth of the intramitochondrial hexagon bodies. The biochemical implications of this study are discussed.     

Ultrastructural and cytochemical studies of nucleolus-like bodies in neurons of rat sympathetic ganglia

Intracytoplasmic fibrillar inclusions, generally referred to as nucleolus-like bodies (NLBs) were studied by means of ultrastructural cytochemistry. The structure of these bodies was visualized by several different staining procedures: conventional electron microscopy and preferential staining methods for localization of various proteins including ribonucleoproteins, basic proteins, glycoproteins and phosphorylated proteins. The results of the cytochemical tests indicate that NLBs have an essentially proteinaceous nature. They consist of ribonucleoproteins, basic proteins and glycoproteins but do not contain phosphorylated proteins. These findings suggest that NLBs are, at least partially, of the same nature as nucleoli and coiled bodies. The origin of NLBs and their possible functional role is briefly discussed.     

Ultrastructural and cytochemical studies of nucleolus-like bodies in neurons of rat sympathetic ganglia

Summary Intracytoplasmic fibrillar inclusions, generally referred to as nucleolus-like bodies (NLBs) were studied by means of ultrastructural cytochemistry. The structure of these bodies was visualized by several different staining procedures: conventional electron microscopy and preferential staining methods for localization of various proteins including ribonucleoproteins, basic proteins, glycoproteins and phosphorylated proteins. The results of the cytochemical tests indicate that NLBs have an essentially proteinaceous nature. They consist of ribonucleoproteins, basic proteins and glycoproteins but do not contain phosphorylated proteins. These findings suggest that NLBs are, at least partially, of the same nature as nucleoli and coiled bodies. The origin of NLBs and their possible functional role is briefly discussed.     

Ultrastructural visualization of exocytosis in the pig pineal gland

Summary The pinealocytes of the pig contain conspicuous dense bodies, the nature and role of which are not yet fully elucidated. The aim of this study was to demonstrate whether or not these structures are involved in the secretion process. The tannic acid-Ringer incubation (TARI)-method, which allows a clear-cut ultrastructural study of secretory discharge by exocytosis, has been used. The results indicate that pig pinealocytes release the content of the dense bodies with an amorphous inner structure into the extracellular space via exocytosis and that this secretion is quantitatively important. The secreted material is proteinaceous in nature; this indicates that polypeptides are released by the pineal.     

Cytochemical observations of the coiled bodies in neurons of rat sympathetic ganglia

Coiled bodies were investigated by means of ultrastructural cytochemistry. Preferential staining methods for localization of various proteins (ribonucleoproteins, basic proteins, phosphoproteins and glycoproteins) and DNA were applied. The results of cytochemical tests revealed that coiled bodies have a proteinaceous nature. They are composed of ribonucleoproteins, probably of nucleolar origin. They also contain phosphoproteins and glycoproteins but lack cytochemically detectable DNA. Coiled bodies present ultrastructural and cytochemical characteristics similar to the fibrillar part of the nucleous and to the interchromatin granules. The origin and possible functional role of coiled bodies are briefly discussed.     

Cytochemical observations of the coiled bodies in neurons of rat sympathetic ganglia

Summary Coiled bodies were investigated by means of ultrastructural cytochemistry. Preferential staining methods for localization of various proteins (ribonucleoproteins, basic proteins, phosphoproteins and glycoproteins) and DNA were applied. The results of cytochemical tests revealed that coiled bodies have a proteinaceous nature. They are composed of ribonucleoproteins, probably of nucleolar origin. They also contain phosphoproteins and glycoproteins but lack cytochemically detectable DNA. Coiled bodies present ultrastructural and cytochemical characteristics similar to the fibrillar part of the nucleous and to the interchromatin granules. The origin and possible functional role of coiled bodies are briefly discussed.     

Cajal bodies and histone locus bodies: Molecular composition and function

The review provides modern classification of evolutionarily conserved coilin-containing nuclear bodies of somatic and germ cells that is based on the characteristic features of their molecular composition and the nature of their functions. The main differences between Cajal bodies and histone locus bodies, which are involved in the biogenesis of small nuclear spliceosomal and nucleolar RNAs and in the 3′-end processing of histone precursor messenger RNA, respectively, are considered. It is shown that a significant contribution to the investigation of the diversity of coilin-containing bodies was made by the studies on the architecture of the RNA processing machinery in oocyte nuclei in a number of model organisms. The characteristics features of the molecular composition of coilin-containing bodies in growing oocyte nuclei (the so-called germinal vesicles) of vertebrates, including amphibians and birds, are described.     

Histochemical characterization of the lead intranuclear inclusion bodies

A battery of histological and histochemical techniques was applied on the lead intranuclear bodies that have resuted in the kidneys of adult Wistar male rats receiving lead acetate in their diet to determine their nature. The intranuclear inclusion bodies have stained strongly with xanthene, anthraquinone, and trisulfonated basophilic dyes and weakly with dyes containing both positive and negative radicals, and they have responded negatively to acidophilic cationic dyes. They have also reacted positively to proteins and lead stains, but weakly to lipid stains, and negatively to Feulgen and methyl green pyronin techniques. The intranuclear bodies proved to be lead lipoprotein complexes containing sulfyhydryl groups and are basic in nature with orthochromatic, eosinophilic, argyrophilic, osmophilic, fuchsinophilic, and sudanophilic characteristics.     

Lipid bodies: cytoplasmic organelles important to arachidonate metabolism in macrophages and mast cells

Much has been learned about the biochemical nature and pharmacologic activity of the products of arachidonic acid (AA) oxidation, but relatively little is known about the structures in nucleated cells into which AA is incorporated and from which it is initially mobilized. To address this question, we administered 3H-AA or other 3H-fatty acids in vitro to human lung mast cells and alveolar macrophages as well as to mouse and guinea pig peritoneal macrophages. The subcellular distribution of 3H label was assessed by electron microscopic autoradiography, and the nature of cell-associated 3H-lipids was determined by thin layer chromatography. Autoradiographic analysis of human lung mast cells localized virtually all of the 3H-AA to cytoplasmic lipid bodies. Lipid bodies are roughly spherical, variable osmiophilic, nonmembrane-bound structures that appear in the cytoplasm of a wide variety of cells, but we have found that these lipid bodies occur with increased frequency in granulocytes, macrophages, and mast cells at sites of inflammatory, immunologic, or neoplastic processes. Macrophages also incorporated 3H-AA predominantly into cytoplasmic lipid bodies. In contrast to mast cells, however, macrophages incorporated 3H-AA into the plasma membrane as well. Stimulation of macrophage phagocytosis resulted in striking alterations of the relationships of lipid bodies to intracellular membranes, so that many lipid bodies appeared adjacent to phagolysosomes. In addition, some phagolysosomes contained 3H label, which along with other morphologic evidence suggested that lipid bodies may discharge their contents into these structures. Mast cell and macrophage cytoplasmic lipid bodies appear to represent a major site of intracellular storage and metabolism of products of AA and perhaps other fatty acids taken up from the external milieu. These heretofore neglected organelles may thus influence cellular function in a wide variety of adaptive or pathologic processes.     

Helminth communities in avocets: importance of the compound community

This paper reports patterns of similarity and overlap in species presence and patterns of linear distribution of intestinal helminths in 22 avocets from 4 populations. Avocets collected from ephemeral bodies of water in Alberta and Manitoba had communities composed largely of species that are avocet specialists plus some that are host generalists. The composition of helminth communities in these hosts was similar to that reported in earlier surveys of avocet helminths. There was little evidence for competition between helminth species in these communities. In contrast, avocets collected from permanent bodies of water in Alberta had communities composed largely of species that are specialists in various duck species, particularly lesser scaup. These helminths were superimposed on the normal community, fitting into linear gaps along the intestine but also overlapping the distributions of avocet specialists. These lesser scaup specialists exhibit interactive patterns amongst themselves and, to some extent, with avocet specialists. Helminth communities in avocets from ephemeral bodies of water have vacant niches and are largely isolationist in nature. Those in avocets from permanent bodies of water are saturated and are more interactive in nature.     

LYSOSOME FUNCTION IN THE REGULATION OF THE SECRETORY PROCESS IN CELLS OF THE ANTERIOR PITUITARY GLAND

The nature and content of lytic bodies and the localization of acid phosphatase (AcPase) activity were investigated in mammotrophic hormone-producing cells (MT) from rat anterior pituitary glands. MT were examined from lactating rats in which secretion of MTH¹ was high and from postlactating rats in which MTH secretion was suppressed by removing the suckling young. MT from lactating animals contained abundant stacks of rough-surfaced ER, a large Golgi complex with many forming secretory granules, and a few lytic bodies, primarily multivesicular bodies and dense bodies. MT from postlactating animals, sacrificed at selected intervals up to 96 hr after separation from their suckling young, showed (a) progressive involution of the protein synthetic apparatus with sequestration of ER and ribosomes in autophagic vacuoles, and (b) incorporation of secretory granules into multivesicular and dense bodies. The content of mature granules typically was incorporated into dense bodies whereas that of immature granules found its way preferentially into multivesicular bodies. The secretory granules and cytoplasmic constituents segregated within lytic bodies were progressively degraded over a period of 24 to 72 hr to yield a common residual body, the vacuolated dense body. In MT from lactating animals, AcPase reaction product was found in lytic bodies, and in several other sites not usually considered to be lysosomal in nature, i.e., inner Golgi cisterna and associated vesicles, and around most of the immature, and some of the mature secretory granules. In MT from postlactating animals, AcPase was concentrated in lytic bodies; reaction product and incorporated secretory granules were frequently recognizable within the same multivesicular or dense body which could therefore be identified as "autolysosomes" connected with the digestion of endogenous materials. Several possible explanations for the occurrence of AcPase in nonlysosomal sites are discussed. From the findings it is concluded that, in secretory cells, lysosomes function in the regulation of the secretory process by providing a mechanism which takes care of overproduction of secretory products.     

Effects of colchicine on myofilament arrangement and the lysosomal system in skeletal muscle

Summary Colchicine was intraperitoneally administered chronically to adult male Sprague-Dawley rats. The ultrastructural study of hind-limb muscles revealed that myofilament desorientation resulted. Bundles of myofilaments were found coursing perpendicular or oblique to the longitudinal axis of the muscle fiber. It is concluded that a colchicine-sensitive factor is involved in maintaining normal orientation of myofibrils in mature muscle. Also found in the sarcoplasm of the colchicine treated animals were complex spheromembranous bodies. These bodies enveloped mitochondria or other organelles and appeared to be derived from the sarcoplasmic reticulum. The lysosomal nature of these bodies is indicated by the localization of acid phosphatase activity in them. Acid phosphatase activity was also displayed in the sarcoplasmic reticulum. The spheromembranous bodies seem to be part of a sarcotubulo-lysosomal system in skeletal muscle.This study was supported in part by N.I.H. Grant RR-5576.The author gratefully acknowledges the technical assistance of Mrs. Patricia Driscoll.     

Origin,structure, composition and age-dependence of mineralized dense bodies (concretions) in the midgut epithelium of the adult housefly, Musca domestica

The epithelial cells of the midgut in 1–40 day old adult female houseflies were examined by electron microscopic, X-ray microanalytic and histochemical techniques in order to study the mode of genesis, chemical nature and age-associated distribution of dense bodies. Dense bodies contain high concentrations of phosphorus, sulphur, chlorine, calcium, iron and copper; they are therefore termed concretions. Concretionary material is initially deposited within Golgi vesicles, lamellar bodies and residual bodies. The average size of the concretion granules and the concentration of the sequestered material increases with age, while new concretions are continually formed throughout life. With advancing age, concretions accumulate in the epithelial cells and occupy a considerable proportion of the cytoplasm in old flies. It is postulated that the concretions sequester superfluous minerals and may play an important role in the excretory system of the adult housefly.     

Does Gibberellic Acid Induce the Transfer of Lipase from Protein Bodies to Lipid Bodies in Barley Aleurone Cells?

We have examined the effect of gibberellic acid (GA₃) on the distribution of the enzyme responsible for mobilizing storage triacylglycerol in aleurone cells of Hordeum vulgare L. cv Himalaya. Using cellular fractionation techniques, we find that, in cells that have not been exposed to hormone, neutral lipase activity is principally associated with a pellet containing the membranes of protein bodies. If the cells are exposed to GA₃ for at least 1 hour, the majority of the lipase activity becomes associated with the lipid body fraction. The nature of the in vivo association between lipid bodies and protein bodies was examined using ultrarapid freezing followed by freeze-fracture electron microscopy. Our analysis indicates that the phospholipid monolayer surrounding the lipid body is directly continuous with the outer leaflet of the bilayer surrounding the protein body. Based on our data, we propose that lipase can be transferred from protein bodies (storage form) to lipid bodies (active form) by lateral diffusion within the plane of the fused phospholipid monolayer, and that the transfer can be controlled by gibberellic acid by an unknown mechanism.     

Large Bodies of Mycoplasma and L-Form Organisms

The large bodies of various Mycoplasma and L-form organisms were studied by ultraviolet fluorescence microscopy of preparations stained with various fluorochromes. Primuline and Thioflavine S specifically stained the outer portion or rim of the large bodies, and the fluorescence characteristics of the stained bodies differed from those for other microorganisms and for spheroplasts and protoplasts. Small granular structures similar in size and morphology to minimal reproductive units were observed within some of the large bodies by phase microscopy and by fluorescence microscopy with acridine orange or Coriphosphine O. Micromanipulation probing of the large bodies revealed their elastic nature; many of the large bodies could be subdivided into two or more smaller circular bodies, each retaining the fluorescence staining properties of the parent body. Under these conditions, however, a few of the large bodies were ruptured, leaving the stainable outer boundary area as a stable residual structure. The large bodies were somewhat resistant to various rigorous treatments normally employed to eliminate viability of Mycoplasma and L-form cultures. Structures similr to large bodies were observed in various natural tissues, and structures resembling large bodies in size, morphology, fluorescence staining characteristics, and reaction to micromanipulation probing were reconstructed from an acetone extract of egg yolk. Overall, the large bodies of Mycoplasma and L-form organisms appeared to be structures resulting from accumulations of metabolic by-products and medium components within or on which minimal reproductive units had become entrapped, although it could not be ruled out that they might be defined structures specifically formed during culture as protective lipoidal sacs for the minimal reproductive units.     

P bodies promote stress granule assembly in Saccharomyces cerevisiae

Recent results indicate that nontranslating mRNAs in eukaryotic cells exist in distinct biochemical states that accumulate in P bodies and stress granules, although the nature of interactions between these particles is unknown. We demonstrate in Saccharomyces cerevisiae that RNA granules with similar protein composition and assembly mechanisms as mammalian stress granules form during glucose deprivation. Stress granule assembly is dependent on P-body formation, whereas P-body assembly is independent of stress granule formation. This suggests that stress granules primarily form from mRNPs in preexisting P bodies, which is also supported by the kinetics of P-body and stress granule formation both in yeast and mammalian cells. These observations argue that P bodies are important sites for decisions of mRNA fate and that stress granules, at least in yeast, primarily represent pools of mRNAs stalled in the process of reentry into translation from P bodies.     

大肠杆菌中利用苏云金芽胞杆菌强启动子p1Ac指导Cry1Ac蛋白表达的特性分析

对利用苏云金芽胞杆菌(Bacillus thuringiensis,Bt)强启动子——cry1Ac基因启动子p1Ac指导cry基因在大肠杆菌中的表达进行了研究。结果显示,大肠杆菌中由启动子p1Ac指导表达的Cry1Ac蛋白与苏云金芽胞杆菌来源的Cry1Ac蛋白在碱溶性、胰蛋白酶活化、杀虫活性等方面有较好的一致性,从而解决了目前商业化载体大肠杆菌表达cry基因时形成不易溶解的包涵体问题。同时,还对p1Ac指导的cry1Ac基因在大肠杆菌中表达的发酵条件进行了初步探索。