Distinct Cytoplasmic Granules Research Articles

Isolation and Purification of Protein Granules from Escherichia coli Cells Overproducing Bovine Growth Hormone

High-level expression of bovine growth hormone in Escherichia coli results in the formation of distinct cytoplasmic granules that are visible with the phase-contrast microscope. These granules were examined by transmission and scanning electron microscopy. Intact granules were isolated from crude cell lysates by differential centrifugation and were further purified by a simple washing procedure that yields nearly homogeneous bovine growth hormone.

Motility of Isospora suis Meronts

The endogenous asexual stages of Isospora suis in piglets consist of two distinct types of meronts, both of which are elongate and retain their sporozoite-shape during merogony (Lindsay et al., 1980, J. Parasitol. 66: 771-779). Sporozoiteshaped, Type I meronts are binucleate, whereas, sporozoite-shaped, Type II meronts are multinucleate. Motility has been described for elongate, sporozoite-shaped meronts of many Eimeria spp. studied both in vivo (Speer and Hammond, 1971, Z. Parasitenkd. 37: 336-353) and in vitro (Speer et al., 1970, J. Protozool. 17: 274-284; Speer and Hammond, 1970, Z. Parasitenkd. 35: 105-118; Speer and Hammond, 1971, loc. cit.; Speer et al., 1973, J. Parasitol. 59: 613-623; Mueller and Speer, 1982, Proc. Helminthol. Soc. Wash. 48: 87-89). However, motility of meronts has not been described for any Isospora species. The present study was undertaken to describe the motility of elongate, sporozoite-shaped, Type I and Type II meronts of Isospora suis in intestinal tissues of experimentally infected pigs. Four 1-day-old piglets were inoculated by stomach tube with 300,000 sporulated oocysts of I. suis that had been stored at 4 C in 2.5% K2Cr207 for 30 days. Intestinal tissues were obtained from two piglets 3 days PI for observations of Type I meronts and from two piglets 4 days PI for observations of Type II meronts. Portions of mid-jejunum and ileum were scraped off with a scalpel, placed on microscope slides with phosphate-buffered saline (pH 7.2), and compressed under a coverslip. Mucosal smears were then observed with Nomarski interference contrast microscopy at room temperature. Elongate, Type I meronts were binucleate and had several distinct cytoplasmic granules, both anterior to and posterior to the nuclei (Fig. 1). Most motile Type I meronts had a sharply-pointed anterior end. Motility of extracellular Type I meronts consisted primarily of gliding and flexing movements lasting 3 to 10 sec. These movements were interrupted by periods of inactivity lasting from 2 to 14 seconds. Euglenoidlike transformations of the anterior end of Type 1 meronts often changed these normally elongate stages to pear-shaped bodies (Fig. 2). Small projections and invaginations of the pellicle were also observed in many Type I meronts. Slight, backward-gliding movements were seen in some mer-

Granular acute lymphoblastic leukemia.

Granules in blasts are most typical of acute myeloblastic leukemia. However, there have been scattered reports of patients with acute lymphoblastic leukemia (ALL) that have lymphoblasts with azurophilic cytoplasmic granules. These reports do not describe immunologic markers or cytogenetics. We report five additional cases with detailed cytologic, immunologic, and cytogenetic studies. At diagnosis one of these patients had central nervous system disease, while the others had no unusual features. Four of the five patients attained remission. The blasts of all five patients contained distinct cytoplasmic azurophilic granules. The granules were negative for peroxidase and chloroacetate esterase and positive for PAS, acid phosphatase, alpha-naphthyl acetate esterase incompletely fluoride inhibited, alpha-naphthyl butyrate esterase, and in one case, Sudan black B. In the one patient studied by electron microscopy, characteristic lymphoblasts contained membrane-bound electron lucent inclusions, which stained positively with non-specific esterase. Immunologic markers showed a common ALL phenotype. Different cytogenetic abnormalities were seen in all cases. It is important to recognize the characteristics of this morphologic subtype of ALL in order to avoid a misdiagnosis of acute nonlymphocytic leukemia.

The mast cell: IV. An ultrastructural and autoradiographic study of the distribution and maturation of peritoneal mast cells in the rat

Ultrastructural studies of peritoneal mast cells in adult and young rats showed that results are comparable to those obtained by light microscopic and histochemical studies as far as their maturation and distribution are concerned. It was also evident that mast cells possess cytoplasmic structures common to other cells including microtubules and microfilaments in addition to their distinctive cytoplasmic granules. Granules appear to develop from the vicinity of the Golgi apparatus as progranules in a structured sequence to full maturity rather than from mitochondria or from the cytoplasm de novo. In newborn and young rats mast cells are mostly immature and exhibit frequent mitotic activity. Autoradiographic studies showed that young Stages 1 and 2 peritoneal mast cells are primarily responsible for mitotic and therefore proliferative activity. It was concluded that the final density of mast cells is achieved in the early stages by proliferation and possibly by heteroplastic differentiation of precursor cells.

Migration of binucleate cells in the sheep placenta during normal pregnancy.

The maternofetal interface in the placentomes of the sheep placenta consists of a fetal cellular chorion layer whose apical microvilli interdigitate with those of a syncytial layer which borders the maternal connective tissue. Most of the granulated binucleate cells found in the chorion epithelium reach neither its basement membrane nor its microvillar junction apex. However, up to one fifth of the binucleate cells can be shown to be part of or push pseudopodia across the microvillar junction or are located within the syncytium. The syncytium and chorionic binucleate cells both have a nuclear chromatin structure and distinctive cytoplasmic granules which are not found in any other placental cells. This suggests that most, if not all, of the syncytium is derived by fusion of fetal binucleate cells which have migrated across the microvillar junction from the chorion, and that the immunological maternofetal junction does not lie between chorion and syncytial layers.

THE HAARSCHEIBE

The Haarscheibe is a specialized spot of epidermis containing many Merkel cell-neurite complexes. It is a highly sensitive, slowly adapting, modality-specific touch receptor occurring in all mammals. Its exact role in signaling sensation in human beings is undetermined, and the function of Merkel cells, with their distinctive cytoplasmic granules, in transducing mechanical force into neural action potentials remains to be determined.

Localization of intracellular polysaccharide granules in Streptococcus mitis

The accumulation of an intracellular glycogen-like polysaccharide was studied by electron microscopy in a strain of Streptococcus mitis which can store up to 50 per cent of its dry weight as intracellular polysaccharide. Storage of polysaccharide was reflected by an increase in the number but not the size of distinct cytoplasmic granules. Synthesis of glycogen appeared to occur near the cell membrane since the granules in the earlier stages of accumulation were usually located there. The average diameter of the granules was about 600 Å and from this measurement the molecular weight of the polysaccharide was estimated to be about 3.3 × 10 7. Each granule would appear to represent a single glycogen macromolecule.