Positive Periodic acid-Schiff Reaction Research Articles

THE ORAL SUCKER OF SOME GASTROINTESTINAL TREMATODES: HISTOLOGICAL AND HISTOCHEMICAL RESEARCH

We conducted histological and histochemical studies of the oral sucker of gastrointestinal trematodes of the family Paramphistomatidae, Fischoeder, 1901 living in the rumen of ruminants, namely, Liorchis scotiae, Paramphistomum cervi and Paramphistomum ichikawai. The oral sucker of paramphistomes and the Liorchis scotiae trematode is a complex muscular organ modified into a pharynx-sucker, the muscle complex of which is formed from longitudinal, circular and radial muscle fibers. In the thick pharynx wall, we found secretory cells, single neurosecretory cells and many desmoblastic cells of connective tissue. Histochemical stains showed intense staining with alcian blue, toluidine blue, bromophenol blue and a positive periodic acid Schiff reaction, which indicates the presence of glycosaminoglycans, total proteins and glycoproteins. Due to this structure, the pharynx sucker of gastrointestinal trematodes is involved in capturing food and evacuating its undigested residues from the helminth's body to the outside. In addition, the substances produced by secretory cells of the pharynx carry out a partial chemical treatment of the food consumed by the parasite and protect the parasite from substances that are metabolites of the host tissues and waste products of symbionts and commensals that inhabit the rumen of ruminants. Thus, trophic adaptation of the parasite in its ecological niche, the rumen of polygastric mammals, is ensured.

A case of cribriform carcinoma of the skin: a newly described rare condition.

Primary cribriform carcinoma of the skin is an indolent, rare, adnexal tumor. Although its malignant potential remains uncertain, no recurrence or metastasis has been reported. A 33-year-old man presented with a solitary, erythematous, subcutaneous nodule on the right knee. The clinical impression was epidermal cyst, and the resected tumor demonstrated a well-circumscribed mass in the dermis and subcutis. The tumor was composed of two regions: a solid component and a cribriform component. The solid component (90%) showed multiple solid nests of epithelial cells. Individual cells had large, oval-to-round, hyperchromatic, pleomorphic nuclei with a nuclear groove. The cribriform component (10%) showed similar neoplastic cells with many prominent lumina. Some lumina had an eosinophilic substance that exhibited a positive periodic acid-Schiff reaction. No recurrence or metastasis was observed within a follow-up period of eight months after excision. In conclusion, we report the first case of primary cribriform carcinoma of the skin in Korea.

Whipple disease diagnosed by enteroscopy: first case report in Colombia of an underdiagnosed disease and literature review

BackgroundWhipple’s disease is a rare systemic disease caused by a gram-positive bacillus called Tropheryma whipplei. First described in 1907 as an intestinal lipodystrophy with histological finding of vacuoles in the macrophages of the intestinal mucous. Usually the symptoms are localized according to the compromised organ. The differential diagnosis is wide. It can be fatal without proper treatment. Recurrence can occur in up to 33% of the cases and usually compromises the neurological system.Case presentationThis article reports the case of a 46-year-old female patient with a history of a 6-month hypochromic microcytic anemia of unknown cause. She consulted for a 6-months oppressive abdominal pain located in the mesogastrium as well as abdominal distention associated with nausea and liquid stools; in addition, she had an 8-month small and medium joint pain, without edema or erythema. Physical examination without relevant findings. Multiple esophagogastroduodenoscopies with normal gastric and duodenal biopsies findings and a normal colonoscopy were performed. Endoscope capsule showed red spots in the duodenum and ulcerations in the jejunum and proximal ileum covered by fibrin; histological report showed macrophages with positive periodic acid-schiff reaction staining (PAS staining), disgnosing Whipple’s disease. Antibiotics were initiated. The patient is currently in the second phase of treatment without gastrointestinal and joint symptoms.ConclusionThis is the first case reported in Colombia. It is a rare entity and difficult to diagnose reason why it is important to continue with clinical investigations to give more clarity about the onset and appropriate diagnose to avoid the delay in treatment of this entity.

A Transplantable Syngeneic Allograft Mouse Model for Nongestational Choriocarcinoma of the Ovary.

Nongestational choriocarcinoma is a rare malignancy in humans with poor prognosis. Naturally occurring choriocarcinoma is also rare in laboratory mice, and no genetic mouse model accurately recapitulates the features of this cancer. Here we report development of a genetically engineered mouse (GEM) model with alterations in Brca2, Trp53, and RB that develops ovarian tumors. Most of the ovarian tumors displayed histological characteristics of nongestational choriocarcinoma of the ovary (NGCO) (47%) with abundant syncytiotrophoblasts and cytotrophoblasts, positive immunolabeling for human chorionic gonadotropin, and positive periodic acid-Schiff reaction. The rest of the ovarian tumors were serous epithelial ovarian carcinoma (SEOC) (26%) or mixed tumors consisting of NGCO and SEOC (26%). We further established syngeneic orthotopic mouse models for NGCO by in vivo passaging of GEM tumors. These metastatic models provide a platform for evaluating new treatment strategies in preclinical studies aimed at improving outcomes in choriocarcinoma patients.

Diplectrum radiale (Quoy & Gaimard, 1824) (Serranidae): A rare case of simultaneous hermaphroditism in a teleost fish

AbstractThis study generates, for the first time, information on the reproductive traits of the simultaneous hermaphrodite Diplectrum radiale. The specimens were captured bimonthly in two distinct ecosystems along the south‐eastern Brazilian coast. The mature ovotestes were removed, preserved in formalin and examined using histological techniques. The results revealed indeterminate fecundity with asynchronous ovarian organization. All spermatogenesis occurs within cysts, and the spermatogonial distribution indicated an unrestricted testicular type. The testicular and ovarian tissues were separated from each other by different ducts, indicating no possibility of internal self‐fertilization. The hydrated oocytes were stored in the accessory reproductive structure for at least 24 hr. The presence of atretic hydrated oocytes within this structure and the positive periodic acid–Schiff reaction of the villi‐like projections revealed the function of the ovary sinus as absorbing unspawned oocytes. The relative batch fecundity ranged from 62 to 209 oocytes/g (126 ± 42) for specimens from the coast and from 52 to 203 oocytes/g (113 ± 57) for those sampled in the estuary. The potential batch fecundity was linearly related to size, weight, and the gonadosomatic and hepatosomatic indices, revealing that these parameters significantly affect the reproductive potential of D. radiale.

<b>Histological and immunohistochemical study of the thyroid gland of the broad-snouted caiman (<i>Caiman latirostris</i>)</b> - doi: 10.4025/actascibiolsci.v35i4.18444

The broad-snouted caiman, Caiman latirostris, is widely distributed in countries of South America. In Brazil it is considered an endangered species because of natural habitat destruction and illegal hunting. In reptiles, the thyroid gland plays an integral part in ecdysis, reproduction, tail regeneration, growth, endocrine function and metabolism rate. The aim of the present study was to characterize the thyroid gland morphology of C. latirostris, based on histochemical and immunohistochemical techniques. The thyroid glands were fixed in Bouin's fluid and serial cross sections were stained with hematoxylin-eosin, Mallory’s trichrome, periodic acid-Schiff (PAS) and Alcian blue (AB pH 1.5 and 2.5). The immunohistochemical technique for 5-HT-IR cells was used. The thyroid gland has a dense irregular connective tissue forms a capsule enveloping the gland. There are several follicular acini of varying size lined by simple cuboidal or columnar epithelium in the thyroid gland. The follicles are connected by interfollicular connective tissue which contains blood vessels. We observed the presence of lymph nodes around the entire gland. There was a positive PAS reaction and negative AB reaction in the colloid. 5-HT-IR cells were detected around the follicle cells. No striking morphological differences were observed between C. latirostris and other domesticated mammals.

Treatment of pregnant spiny mice at mid gestation with a synthetic glucocorticoid has sex-dependent effects on placental glycogen stores

IntroductionElevated maternal glucocorticoids during human pregnancy suppress fetal growth, more so if the fetus is male. The synthetic glucocorticoid dexamethasone (DEX) is known to affect placental glucose transport, but whether this also affects placental glycogen stores has not been investigated. MethodWe examined the short and long term consequences of a single, 60 h exposure to DEX at mid gestation on the glycogen pathway in the placenta of the spiny mouse, with a focus on identifying sex-dependent differences in expression of genes involved in glycogen cell formation (PCDH12), and regulation of glycogen synthesis (GSK3B, GYS1, GBE1, FOXO1, UGP2). ResultsPlacentas from female fetuses had increased amounts of glycogen on day 25 of gestation (term is 39 days) as identified by positive Periodic acid Schiff (PAS) reaction staining. DEX administration initially reduced expression of GSK3B, GYS1, GBE1, FOXO1, UGP2 in both male and female placentas, but reduced histologically detectable glycogen storage in placentas of female fetuses only. The DEX-induced reduction in expression of GSK3B and UGP2 persisted until day 37 of gestation, an effect that was significantly greater in the male placenta. Discussion/conclusionWe conclude that constitutive placental glycogen storage is regulated in pregnancy in a sex-dependant manner, and that glucocorticoids such as DEX induce sex-dependent changes in glycogen storage. Placental glycogen metabolism and its response to glucocorticoids may contribute to the different sensitivities of male and female fetuses to the effects of maternal illness and stress in utero.

Structural Changes of Goat Parotid Salivary Gland: Pre- and Post-Weaning Periods

Previously, the structure of the adult goat parotid salivary glands (PGs) was studied. However, little information was elucidated of the juvenile ones. This study aimed to clarify the correlations between the structure of goats' PGs and the nature of food intake among milk-suckling kids (MSKs) and diet-fed goats (DFGs). The secretory endpieces of the goats' PGs are of the pure serous type. The serous cells in MSKs showed apical accumulation of numerous secretory granules (SGs) of smaller size and of more intense positive periodic acid-Schiff reaction. Ultrastructurally, most of the SGs in the DFGs contained peripherally located inclusions that showed dense reaction products for acid phosphatase. In MSKs, the PGs showed less-developed basal infoldings, sparseness of the inter-cellular inter-digitations, fewer inter-cellular canaliculi and microvilli and also less-developed myoepithelial cells with fewer and shorter cytoplasmic processes. In conclusion, the less-developed membrane specializations and myoepithelial cells, as well as the accumulated SGs in the PGs of MSKs, suggest that it secretes less saliva with a little secretory activity than that of DFGs, which may be correlated with the reduced masticatory activity.

In vitro differentiation of human cord blood-derived unrestricted somatic stem cells towards an endodermal pathway

Pluripotent unrestricted somatic stem cells (USSC) from UC blood can differentiate into hepatic cells in the in utero sheep model, resulting in 20% human albumin-producing parenchymal hepatic cells without cell fusion or tumor-formation events. Additionally, we have shown in vitro differentiation of USSC by hepatocyte growth factor and oncostatin M induction, causing changes in the gene expression towards the endodermal lineage. Positive glycogen synthase expression and a positive periodic acid-schiff reaction demonstrated a functional production of polysaccharides in the cells. We describe the in vitro differentiation of USSC towards an endodermal pathway using different matrices, growth factors and organic substances. Also, co-cultures of USSC with primary cells of endodermal tissue were prepared to mimic the biologic niche. We investigated the effect of direct co-culture of USSC with primary rat hepatocytes or with sheep tissue of endodermal origin. Direct co-cultures were set up to ensure cell-cell contacts. For co-cultures without cell-cell contacts, transwell inlays with 1-microm membranes were used to separate the cells. Furthermore, the effect of endodermally conditioned medium was investigated. Changes in the gene expression patterns were analyzed by RT-PCR. We have shown that USSC can differentiate in vitro into an endodermal-like cell with a phenotype similar to hepatic cells. Differentiation of USSC with growth factors, retinoic acid, matrigel matrix and different co-cultures led to an increased expression of albumin and also to the detection of GSC, SOX 17, Cyp2B6, Cyp3A4, Gys2, HNF4a, ISL-1 and Nkx6.1. In addition, functional albumin secretion was observed. Although the differentiation assays demonstrated here produce only an immature hepatocyte-like cell, endodermaly differentiated USSC might be a useful alternative for cell replacement in the future.

Ultrastructural differentiation of Toxoplasma gondii schizonts (types B to E) and gamonts in the intestines of cats fed bradyzoites

The ultrastructural characterisitics of four types of Toxoplasma gondii schizonts (types B, C, D and E) and their merozoites, microgamonts and macrogamonts were compared in cats killed at days 1, 2, 4 and 6 after feeding tissues cysts from the brains of mice. Schizonts, merozoites and gamonts contained most of the ultrastructural features characteristic of the phylum Apicomplexa. All four types of schizonts developed within enterocytes or intraepithelial lymphocytes. Occasionally, type B and C schizonts developed within enterocytes that were displaced beneath the epithelium into the lamina propria. Type D and E schizonts and gamonts developed exclusively in the epithelium. Tachyzoites occurred exclusively within the lamina propria. Type B schizonts formed merozoites by endodyogeny, whereas types C to E developed by endopolygeny. The parasitophorous vacuoles surrounding type B and C schizonts consisted of a single membrane, whereas those surrounding types D and E schizonts were comprised of two to four electron-dense membranes. The parasitophorous vacuole of type B schizonts had an extensive tubulovesicular membrane network (TMN); the TMN was reduced or absent in type C schizonts and completely absent in types D and E schizonts and gamonts. Type B merozoites were ultrastructurally similar to tachyzoites, except that they were slightly larger. Type C merozoites exhibited a positive periodic acid-Schiff reaction by light microscopy and ultrastructurally contained amylopectin granules. Rhoptries were labyrinthine in type B merozoites but were electron-dense in types C–E. The development of microgamonts, macrogamont and oocysts is also described.

Histochemical study of follicles in the senescent porcine pituitary gland.

Follicles displaying a positive periodic acid-Schiff reaction to a colloid substance in the anterior pituitary gland have been observed in many vertebrates, including humans. It is also known that these follicles greatly increase in number and size with age. We therefore performed histochemical analysis of these colloid follicles in the senescent porcine pituitary gland in order to clarify their nature and biological significance. Results from various histological stains suggest that the colloid contains some polysaccharides or glycoproteins. In addition to the histological stains, lectin histochemistry revealed that the colloid contains sialic acid, N-acetyl galactosamine and galactose. Also, lectin staining indicated that some glycoproteins, most likely Asn-linked sialoglycoproteins, are localized in the colloid. The cells (FS cells) surrounding the colloid were densely stained with an antibody to S-100 protein but were not stained with antibodies to any other anterior pituitary hormones. Frequently mammotrophs (PRL cells), and occasionally gonadotrophs (LH cells) were found closely associated with folliculo-stellate cells (FS cells which lay next to the large colloid containing follicles. This suggests that not only are the FS cells important in the production of the colloids, but the adjacent LH and PRL cells in some way also contribute to their formation.

Presumed Central Nervous System Whipple's Disease in a Child: Case Report

Whipple's disease is a rare, chronic, multisystem illness that is pathologically characterized by the accumulation of macrophages in the involved tissue that have a positive periodic acid-Schiff reaction. It is typically seen in middle-aged white men, and only four cases involving persons younger than 15 years of age have been reported. CNS Whipple's disease without intestinal manifestations is rare; only six cases have been reported in the literature, all involving adults. We report the case of a young boy with clinical, laboratory, radiographic, and pathological signs and symptoms consistent with CNS Whipple's disease who responded to therapy with trimethoprimsulfamethoxazole.

Nucleus Pulposus Regeneration After Chemonucleolysis with chymopapain?

Chemonucleolysis was unsuccessful in 100 out of 519 patients with herniated lumbar discs treated within a period of 3 years. These patients were subsequently submitted to open surgery. Disc material from 88 of the 100 patients was examined by light microscopy (hematoxylin and eosin, van Gieson's, Nissl's and periodic acid-Schiff staining) to verify the effect of enzymatic activity compared to the histologic findings in a similar control group. In 84 of the 88 cases, signs of enzymatic activity were revealed by eosinophilia of the ground substance, altered Nissl staining and positive periodic acid-Schiff reaction within the chondrocyte halos. These alterations indicate that the enzyme was active and confirm the results of previous studies with smaller numbers of cases. Histologic alterations were quantified according to the intensity and extent of staining. The signs of enzymatic activity were significantly (P < 0.01) stronger after short time intervals between chemonucleolysis and surgery than after long intervals. These findings may be interpreted as indicating a regenerative potential of the nucleus pulposus.

Homogeneous production of feline interferon in silkworm by replacing single amino acid code in signal peptide region in recombinant baculovirus and characterization of the product.

In a previous paper we reported that we constructed a recombinant baculovirus named BmFeIFN1 which produced recombinant feline interferon (FeIFN) in silkworm after infection. High purification of FeIFN in body fluid from the larvae revealed that two kinds of FeIFN were produced by the BmFeIFN1. The difference between the two in the NH2-terminal amino acid sequence was clarified, and two kinds of processing at different sites in FeIFN precursor were suggested. Changing one residue of the amino acid sequence in deduced signal peptide by site directed mutagenesis of encoding cDNA led to the production of homogeneous FeIFN whose NH2-terminal three amino acid sequence was identical to the conserved sequence of human interferon-alpha. We designated the FeIFN produced as rFeIFN. Amino acid sequence analysis revealed that rFeIFN consisted of 170 amino acid residues. The COOH-terminal amino acid of the rFeIFN is Glu which is located at one amino acid residue upstream to the COOH-terminal amino acid deduced from the nucleotide sequence. Positive periodic acid Schiff reaction, undetectability of Asn at position 79 by automated protein sequencer, and detectability of N-acetylglucosamine not N-acetylgalactosamine suggested that rFeIFN was N-glycosylated. rFeIFN was stable at pH 1.5 at 4 degrees C for at least 50 days, and had an antiviral action on feline calicivirus or feline herpesvirus in vitro. Its isoelectric point was pI 6.5. Comparing the structure and biosynthesis of rFeIFN with those of HuIFNs, rFeIFN may be classified as omega-type.

Mucins in breast carcinoma

Mucins produced by breast carcinoma have been shown to be neutral and sialomucins. Colonic mucins were found to be sulfated with an o-acylated sialomucin component that was reported by Culling to be specific to normal colonic epithelium and colonic adenocarcinoma. This type of molecule gives a positive staining after potassium hydroxide/periodate borohydride (KOH/PBT) treatment. We studied the types of mucin in five medullary carcinomas, 10 infiltrating duct carcinomas, and 10 infiltrating lobular carcinomas of the breast. Twenty-two of 25 cases were positive for neutral mucins; 14 of 25 were positive for sialomucin. Sulfated mucins were found in five of 10 cases of infiltrating lobular carcinoma, and in six of 10 cases there was a positive periodic acid-Schiff reaction following KOH/PBT. This study illustrates the presence of sulfated mucin and o-acylated sialomucin in infiltrating lobular carcinoma of the breast. Thus, mucin stains cannot be used in differentiating metastatic breast carcinoma from colonic carcinoma. The significance of this finding and its relation to tumor histogenesis, typing, and biologic behaviors require further analysis.

Acidic Proteins from Human Brain: Purification and Properties of Glu-20 and Glu-35 Proteins, and Immunochemical Comparison with Glu-50 Protein

In a continuation of previous work [Nomata et al. (1983) J. Biochem. 93, 825-831], this paper reports the purification and properties of the two other acidic proteins from human brain, and the immunochemical comparison of the three proteins. The protein described previously was named Glu-50 protein, because 50% of its amino acid residues were glutamic acid. By analogy, the proteins reported here were named Glu-20 and Glu-35 proteins on the basis of their glutamic acid contents. Both proteins were purified to a homogeneous state from human brain by ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and gel filtration on Sephadex G-75 and G-100, like Glu-50 protein. The molecular weights of the Glu-20 and Glu-35 proteins in the native state were 61,000 and 48,000 daltons and the values in SDS medium were 60,000 and 16,000, respectively, suggesting that Glu-20 protein is a monomer, and Glu-35 a trimer. The isoelectric points of Glu-20 and Glu-35 proteins were pH 4.2 and 3.6, respectively. Glu-20 protein contained 20.5% Glu, 18.4% Asp and 10.5% Lys, and Glu-35 protein contained 33.9% Glu and 17.2% Asp. The N-terminal amino acids of both proteins were Gly, whereas the C-termini of Glu-20 and Glu-35 proteins were Leu and Lys, respectively. Glu-20 protein gave a slightly positive periodic acid-Schiff reaction, suggesting that it is a glycoprotein, but Glu-35 protein gave a negative reaction. The three acidic proteins, Glu-50, Glu-35, and Glu-20 proteins, were compared immunochemically. Antibodies could be produced in rabbits against Glu-50 and Glu-20 proteins only after immunization with the performate-oxidized proteins, but no antibody could be produced against Glu-35 by similar immunization. Anti Glu-50 antibody reacted only with Glu-50 protein, not with Glu-35 or Glu-20 protein, calmodulin, or S-100 protein. Similarly, anti Glu-20 antibody was specific for Glu-20 protein and did not cross-react with Glu-35 or Glu-50 protein, calmodulin, or S-100. Anti S-100 antibody did not react with Glu-50, Glu-35, or Glu-20 protein. The cross-reactivities of these antibodies were tested with extracts of various tissues of a goat. Anti Glu-50 antibody reacted only with an extract of the brain, not with extracts of other tissues, whereas anti Glu-20 antibody reacted with all the tissue extracts examined.

Molecular organization and selective solubilization of lipids and proteins in the envelope of mycoplasmal virus L2.

The composition and molecular organization of mycoplasmal virus L2 (MVL2) were studied and compared with those of the cell membrane of the host, Acholeplasma laidlawii strain JA1. The virus contained 0.2-0.25 mumol of polar lipids per mg of viral protein. The lipid species of the MVL2 were the same as those of the host cells. Nevertheless, the proportions between the various polar lipids were different, with a much lower content of phosphatidylglycerol in the viral lipids. Despite these quantitative differences, the fatty acid composition of MVL2 was similar to that found in the host cells, a similarly allowing alteration of the fatty acid composition and study of its effect on viral absorption, penetration, and release. Pulse-chase experiments revealed that the lipids incorporated into the virus were synthesized before and after infection. Electron paramagnetic resonance spectrometry suggested that the viral lipid domain had the properties of a lipid bilayer. Nevertheless, the hydrocarbon chains in the MVL2 envelope were less mobile than those in membranes of the host cells, a difference apparently due to the different content, composition, and disposition of proteins in the MVL2 envelope. The electrophoretic pattern of MVL2 polypeptides was dominated by four major and five minor bands distinct from the polypeptides present in A. laidlawii membranes. None of the polypeptides gave a positive periodic acid-Schiff reaction, a result suggesting the absence of glycoproteins. Selective solubilization experiments excluded the possibility that one or more of the major polypeptides was associated with a capsid structure. Lactoperoxidase-mediated iodination of intact viral particles revealed that at least two of the major polypeptides were localized on the external surface of the viral envelope. The susceptibility of these polypeptides to brief proteolytic treatment and the finding that the infectivity of the virus was dramatically affected by such treatment suggested that these polypeptides were playing a role in recognition and/or attachment of the virus to the host cells.

A Clotting Enzyme Associated with the Hemolymph Coagulation System of Horseshoe Crab (Tachypleus tridentatus): Its Purification and Characterization12

A clotting enzyme associated with the hemolymph coagulation system of Japanese horseshoe crab (Tachypleus tridentatus) was highly purified from the amebocyte lysate. The method for purification consisted of gel-filtration of the lysate on a pyrogen-free Sepharose CL-6B column and affinity chromatography of the endotoxin-treated clotting enzyme on a benzamidine-Sepharose 4B column. Through these procedures, about 3 mg of the purified enzyme was obtained from 70 ml of the lysate and about 390-fold purification was achieved. The purified preparation was found to give a single major band, respectively, on polyacrylamide-gel disc electrophoresis at pH 3.2 in the presence of 6 M urea and on sodium dodecyl sulfate (SDS)-gel electrophoresis in the presence and absence of 2-mercaptoethanol. It also gave a single symmetrical peak on QAE-Sephadex A-25 column chromatography. The molecular weight of the clotting enzyme was estimated to be approximately 42,000 for the unreduced sample by SDS-gel electrophoresis. For the reduced sample, it was 30,000, suggesting that the protein consists of plural polypeptide chains bridged by disulfide(s). The Tachypleus clotting enzyme was a glycoprotein, as shown by the positive periodic acid-Schiff reaction for the protein band on SDS-gel and the amino acid analysis. The purified clotting enzyme transformed Tachypleus coagulogen to coagulin gel and hydrolyzed a chromogenic peptide substrate, Tos-Ile-Glu-Gly-Arg-p-nitroanilide for Factor Xa, liberating p-nitroaniline. The enzyme was sensitive to DFP and benzamidine. It was also inhibited partially by PCMB. Antithrombin III and alpha 2-plasmin inhibitor (alpha 2-antiplasmin) were very effective inhibitors of this enzyme among ten kinds of naturally occurring proteinase inhibitors tested. The clotting enzyme had a restricted specificity towards protein substrates and activated only prothrombin among plasma zymogens including Factor IX, Factor X, fibrinogen, plasminogen and prekallikrein. The cleavage sites of bovine prothrombin for this enzyme were the same Arg-Thr and Arg-Ile linkages as those for Factor Xa, resulting in the formation of alpha-thrombin. These results indicate that the horseshoe crab clotting enzyme is a Factor Xa-like serine proteinase rather than alpha-thrombin. It seems likely that the Tachypleus clotting enzyme is a prototype of mammalian serine proteinases participating in blood coagulation.

Composition and molecular organization of lipids and proteins in the envelope of mycoplasmavirus MVL2

MVL2 virus was purified from culture supernatants of infected Acholeplasma laidlawii cells by differential centrifugation, followed by velocity centrifugation in sucrose gradients. The purified virus contained 0.08 to 0.1 mumol of lipid phosphorous per ml of viral protein. Thin-layer chromatography of viral lipids revealed the presence of phospho-, glyco-, and phosphoglycolipids identical with those found in the host cell membrane, but the relative amount of phosphatidylglycerol was much lower than that in the virus. The fatty acid composition of lipids incorporated into the virus included lipids synthesized before and after infection. The freedom of motion of spin-labeled fatty acids in MVL2 depended markedly on temperature and on the position of the nitroxide group on the hydrocarbon chain of the probe, suggesting that the local environment of the probe has the properties of a lipid bilayer. Nevertheless, the lipid hydrocarbon chains in MVL2 appear to be less mobile than those in membranes of the host cells. Polyacrylamide gel electrophoresis of purified MVL2 revealed four major and about five minor polypeptide bands. None of the polypeptide bands gave a positive periodic acid-Schiff reaction. Lactoperoxidase-mediated iodination, followed by proteolytic digestion of intact MVL2 particles, revealed that at least two major polypeptides are localized on the external surface of the viral envelope.

Periodic Acid‐Schiff Reaction Changes During the Course of Relapsing Lymhpoblastic Leukaemia

Bone marrow smears taken at diagnosis and subsequent haematological relapse from 41 patients with lymphoblastic leukaemia (ALL) were compared to assess the proportion of blast cells showing a positive periodic acid-Schiff (PAS) reaction at different stages of the same disease. 20 patients never displayed more than 10% PAS positive blasts at any stage, and of these 8 never had any PAS positivity at all. 7 patients maintained a proportion of PAS positive cells over 10% of the total but with no loss or gain in the numbers of such cells. 14 patients showed a significant change in the PAS reaction during the course of their disease, 7 showing a marked reduction in PAS positive cells, and 7 showing an equally marked increase. From these results it seems that the PAS reaction does not identify a sub-type of ALL or mark the degree of differentiation of a given case. It could be indicative of a specific stage of the lymphoblast mitotic cycle.