Band Of Apparent Molecular Mass Research Articles

Screening of Potentially Probiotic Lactobacillus Possessing Surface Layer Protein from Iranian Traditional Dairy Products

One of the most commonly observed surface structures on the prokaryotic cell envelopes is monomolecular crystalline array of proteinaceous subunits termed Surface Layers or S-layers. Due their self assembly ability and the highly ordered, regular structure down to the nanometer scale, S-layers were demonstrated to possess a great potential for nanobiotechnological applications. Some probiotic bacteria, such as Lactobacillus spp. have been found to possess S-layers. In this perspective, the objectives of this study were isolation and identification of Lactobacillus species from traditional dairy products carrying surface (S) layer protein and investigation of important prerequisite of probiotic interest, such as the capability to survive at low pH and in presence of bile salts. The protein profile of intact Lactobacillus isolates was analyzed in SDS-PAGE. The protein bands of 45–60 kDa were present in two of the 25 isolates, suggesting the presence of S-layer proteins in these strains. The above mentioned proteins were recovered in the guanidine hydrochloride extracts. After dialysis, the extracted proteins showed a significant band of apparent molecular mass of 50–60 kDa in SDS-PAGE. The strains possessing S-layers protein was identified both biochemically and by 16S rRNA sequencing. The 16S rRNA gene sequence analysis revealed that two isolates exhibited maximum similarity with the 16S rRNA sequence of Lactobacillus brevis spp. These two isolates were resistant to acid and bile in which their viability in acidic condition were between 51.6% and 77.8% and bile resistance of two isolates was approximately 99% after 24 h.

Partial characterization of serine peptidases in larvae of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), reveals insensitive peptidases to some plant peptidase inhibitors

Digestive serine peptidases are the major proteolytic enzymes in some coleopterans, including Prostephanus truncatus (Horn). These enzymes have become important targets for the control of insect pests by using plant peptidase inhibitors. Recently, the effect of a trypsin inhibitor from Hyptis suaveolens seeds was tested in artificial diets on P. truncatus with no significant effect on its growth and development (Aguirre et al., 2009) suggesting that the proteolytic system of this insect needs to be studied. In this work, the serine peptidases of this coleopteran were analyzed. Three types of serine peptidase activities were detected: trypsin-like activity with the presence of five peptidases between 23 and 100 kDa; elastase-like activity composed of four peptidases between 42 and 68 kDa, one type of chymotrypsin-like activity which recognized a large substrate (CA) and is composed of eight peptidases between 17 and 95 kDa and another type of chymotrypsin-like activity that recognized a short substrate (CB) with a single activity band of apparent molecular mass of 155 kDa. Most of these activities were composed of anionic peptidases with alkaline optimal pH. In addition, the inhibitory effect of two types of peptidase inhibitors (PI's): synthetic and plant peptidase inhibitors (PPI's) were tested. In general, trypsin-like activity was more sensitive to PPI's whereas CB and elastase-like activities unexpectedly, were unaffected. These results reflect the variety of the P. truncatus serine peptidases, revealing also the presence of two groups of PPI-resistant peptidases that could be playing an important role to circumvent the detrimental effect of plant serine peptidase inhibitors.

A novel full-length gene of human ribosomal protein L14.22 related to human glioma

This study was undertaken to obtain differentially expressed genes related to human glioma by cDNA microarray and the characterization of a novel full-length gene. Total RNA was extracted form human glioma and normal brain tissue, and mRNA was used as a probe. The results of hybridization procedure were scanned with the computer system. The gene named 507E08 cone was subsequently analyzed by northern blot, bioinformatic approach, and protein expression. Fifteen differentially expressed genes were obtained from human glioma by hybridization and scanning for four times. Northern blot analysis confirmed that the 507E08 clone was low expressed in human brain tissue and over expressed in human glioma tissues. The analysis of BLASTn and BLASTx showed that the 507E08 clone was a novel full-length gene, which codes 203 amino acid of protein and is called human ribosomal protein 14.22 gene. The nucleotide sequence had been submitted to the GenBank with the accession number of AF329277. After expression in E. coli., protein yielded a major band of apparent molecular mass 22 kDa on an SDS-PAGE gel. cDNA microarray technology can be successfully used to identify differentially expressed genes. The novel full-length gene of human ribosomal protein 13.22 may be correlated with the development of human glioma.

Detection of NADPH-diaphorase activity in Paramecium primaurelia

Recently, we showed that Paramecium primaurelia synthesizes molecules functionally related to the cholinergic system and involved in modulating cell–cell interactions leading to the sexual process of conjugation. It is known that nitric oxide (NO) plays a role in regulating the release of transmitter molecules, such as acetylcholine, and that the NO biosynthetic enzyme, nitric oxide synthase (NOS), shows nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity. In this work, we detected the presence of NADPH-d activity in P. primaurelia. We characterized this activity histochemically by examining its specificity for β-NADPH and α-NADH co-substrates, and sensitivity both to variations in chemico-physical parameters and to inhibitors of enzymes showing NADPH-d activity. Molecules immunologically related to NOS were recognized by the anti-rat brain NOS (bNOS) antibody. Moreover, bNOS immunoreactivity and NADPH-d activity sites were found to be co-localized. The non-denaturing electrophoresis, followed by exposure to β-NADPH or α-NADH co-substrates, revealed the presence of a band of apparent molecular mass of about 124 kDa or a band of apparent molecular mass of about 175 kDa, respectively. In immunoblot experiments, the bNOS antibody recognized a single band of apparent molecular mass of about 123 kDa.

Expression and immunolocalisation of odorant-binding and chemosensory proteins in locusts

We have identified, cloned and expressed a new chemosensory protein (CSP) in the desert locust Schistocerca gregaria belonging to a third sub-class of these polypeptides. Polyclonal antibodies stained a band of 14 kDa, as expected, in the extracts of antennae and palps of the adults, but not in the 4th and 5th instars. In the related species Locusta migratoria, instead, the same antibodies cross-reacted only with a band of apparent molecular mass of 35 kDa in the extract of 1st-5th instars, but not in the adults. The recombinant protein binds the fluorescent probe N-phenyl-1-naphthylamine, but none of the compounds so far reported as pheromones for S. gregaria. The expression of the odorant-binding protein (OBP) and of CSPs of sub-classes I and II was also monitored in antennae, tarsi, palpi, wings and other organs of solitary and gregarious locusts in their nymphal and adult stages. OBP was found to be antenna specific, where it is expressed at least from the 3rd instar in both solitary and gregarious locusts. CSPs, instead, appear to be more ubiquitous, with different expression patterns, according to the sub-class. Immunocytochemistry experiments revealed that OBP is present in the sensillum lymph of sensilla trichodea and basiconica, while CSP-I and CSP-III were found in the outer sensillum lymph of sensilla chaetica and in the sub-cuticular space between epidermis and cuticle of the antenna. Sensilla chaetica on other parts of the body showed the same expression of CSP-I as those on the antenna.

Lactobacilli isolated from kefir grains: evidence of the presence of S-layer proteins.

In the present study we report for the first time the presence of S-layer proteins in Lactobacillus kefir and Lactobacillus parakefir isolated from kefir grains. Soluble whole-cell protein profile obtained either by mechanical disruption (X-press) or by a combined treatment with lysozyme and SDS on whole cells, showed a significant band of apparent molecular mass of 66-71 kDa as measured by SDS-PAGE. The intensity of this band was considerably reduced when cells were treated with 5 M-LiCl. The above mentioned proteins were recovered in the LiCl extracts. After dialysis and concentration, the proteins extracted were able to reassemble in a regular array. Negative staining of these protein preparations were analysed by transmission electron microscopy and a paracrystalline arrangement was seen. Thin sections of bacteria analysed by transmission electron micrographs showed an outermost layer over the bacterial cell wall, that was lost after the LiCl treatment. The production of this surface structure under different culture conditions was also evaluated. Finally, the relationship between the presence of S-layer proteins and surface properties (e.g. adhesion to Caco-2 cells, autoaggregation, and hemagglutination) was investigated.

Unsaturated fatty acid-activated protein kinase (PKx) from goat testis cytosol

The cytosolic fraction of goat cauda epididymis possesses a protein kinase (PKx) activity which is stimulated by a number of unsaturated fatty acids of which arachidonic acid is the best activator in absence of cAMP or Ca 2+. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and diacylglycerol have no effect either alone or in combination. The membrane fraction does not show any appreciable kinase activity even after detergent treatment. PKx migrates as a single band of apparent molecular mass of 116 kDa on 10% SDS–PAGE after sequential chromatographic separation on DEAE–cellulose, phenyl–Sepharose, high-Q anion exchange and protamine–agarose affinity column. PKx phosphorylates histone H1, histone IIIs and protamine sulfate, but not casein. However, the best phosphorylation was obtained with a substrate based on PKC pseudosubstrate sequence (RFARKGSLRQKNV). The kinase phosphorylates two endogenous cytosolic proteins of 60 and 68 kDa. Ser residues are primarily phosphorylated although a low level of phosphorylation is observed on Thr residues also. Ca 2+ and Mn 2+ inhibit PKx activity in the micromolar range. Staurosporine is found to inhibit the PKx activity to a significant level at sub-nanomolar concentration. Lyso-phosphatidylcholine and certain detergents at very low concentrations (<0.05%) stimulate enzyme activity to some extent. The immuno-crossreactivity study with antibody against different PKC isotypes suggests that the protein kinase under study is not related to any known PKC family. Even the antibody against PKN (a related protein kinase reported in rat testis found to be activated by arachidonic acid) does not cross-react with this protein kinase. Hence we believe that the protein kinase (PKx) reported here is different even from the PKN of rat testis. The phosphorylation of endogenous proteins by the protein kinase may be involved in cell regulation including fertility regulation and signal transduction.

Quantification of prolactin messenger ribonucleic acid, pituitary content and plasma levels of prolactin, and detection of immunoreactive isoforms of prolactin in pituitaries from turkey embryos during ontogeny.

The content of prolactin mRNA as well as total prolactin content and type of isoforms of prolactin were measured in single pituitary glands from turkey embryos and poults. Levels of mRNA and pituitary content of prolactin remained low until 5 days before hatching, while plasma concentrations remained low until 2 days before hatching. Levels of prolactin mRNA then increased until the day of hatch, stayed stable during the 3 first days of age, and significantly increased until 2 wk of age. Similar changes were observed in pituitary content and plasma levels of prolactin. Two immunoreactive bands of apparent molecular masses of 24 and 27 kDa, corresponding to the nonglycosylated and glycosylated form of prolactin, respectively, were visualized on Western blots. In pituitary glands from embryos at 22 days of incubation, 31.5% of the protein was glycosylated, whereas in embryos at 27 days of incubation and poults at 1 and 7 days of age, 48.6%, 48.0%, and 56. 0% of prolactin was glycosylated, respectively. The results indicate that the increases in the synthesis and the release of prolactin occur mainly around and after the time of hatching in the turkey embryo. Higher percentages of glycosylated isoforms were associated with increasing levels of total prolactin in the pituitary gland. Thus, the synthesis of prolactin and its post-translational modifications may be important factors involved in the physiologic changes occurring around the time of hatching.

Purification and Characterization of an Allergy-induced Melanogenic Stimulating Factor in Brownish Guinea Pig Skin

We have demonstrated recently that phenylazonaphthol (PAN) allergy-induced hyperpigmentation in brownish guinea pig skin is associated with the concomitant appearance of a melanogenic soluble factor(s) that activates the intracellular signal transduction system, including phosphatidylinositol turnover subsequent to ligand-receptor binding in cultured guinea pig melanocytes. In this study we have purified and characterized the PAN-induced melanogenic stimulating factor (PIMSF) that occurs in allergy-associated hyperpigmented skin. By successive column chromatography on TSK 2000SW, Mono Q, and octadecyl-NPR, the PIMSF was purified to homogeneity with a single band of apparent molecular mass of 7.9 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The specific bioactivity of PIMSF increased by 5,195-fold over the original skin homogenate. In cultured guinea pig melanocytes, this purified PIMSF had the potential of activating an intracellular signal transduction system such as inositol 1,4,5-trisphosphate formation and intracellular calcium levels through a pertussis toxin-sensitive G protein-coupled receptor. PIMSF consistently caused a rapid translocation of cytosolic protein kinase C (PKC) to membrane-bound PKC within 5 min of treatment with a return to the basal level after 120 min. The stimulating effects of PIMSF on proliferation and melanization of cultured guinea pig melanocytes were abolished completely by a PKC down-regulating agent (phorbol 12,13-dibutyrate). PIMSF was similar in molecular mass to rat growth-related oncogene alpha (GRO-alpha; molecular mass of 7.9 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had immunocross-reactivity with GRO-alpha upon Western immune blotting analysis. Further, the stimulatory effect of purified PIMSF on DNA synthesis of cultured guinea pig melanocytes was suppressed markedly by the addition of anti-rat GRO-alpha antibody, implying that the PIMSF is apparently identical to GRO-alpha. These findings suggest that PAN allergy provides a new mechanism of hyperpigmentation in which biological factors such as the GRO-alpha superfamily generated within allergy-induced skin stimulate melanocytes through activation of the PKC-related signal transduction pathway.

B- and T-cell autoantigens in pristane-induced arthritis.

Pristane-induced arthritis (PIA) is a murine disease resembling rheumatoid arthritis (RA) which is characterized by autoimmune responses to joint tissues. To identify the range of potential antigens targeted in PIA, proteins from arthritic or normal joint extracts were fractionated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and systematically screened for the ability to react with either serum IgG, or cultured splenic T cells, obtained from healthy or arthritic mice. Extracts from both normal and arthritic animals contained multiple proteins that were capable of reacting with murine serum IgG in immunoblotting experiments. In healthy controls, more bands were identified in extracts prepared from 30-week-old mice than from 8-week-old animals, but the widest range of proteins bound were derived from arthritic joints. Furthermore, the sera from PIA-positive mice reacted with more bands from each of the extracts than did normal sera. Fractionated extracts prepared from healthy joints failed to stimulate the in vitro proliferation of splenic T cells from either normal or arthritic animals. When arthritic joint components were screened, T cells from healthy mice responded weakly to some fractions, but multiple fractions elicited strong proliferation by T cells from mice with PIA. A band of apparent molecular mass 60000 was the protein most commonly bound by serum IgG from arthritic mice, and the corresponding fraction stimulated the highest responses by T cells from PIA-positive animals. These results are consistent with the notion that the 60,000 MW mammalian heat-shock protein is an important antigen in PIA, but that the autoimmune response diversifies with the development of arthritis to target multiple joint components.

Cloning and expression of cystolic phospholipase A2 (cPLA2) and a naturally occurring variant. Phosphorylation of Ser505 of recombinant cPLA2 by p42 mitogen-activated protein kinase results in an increase in specific activity.

Full-length cytosolic phospholipase A2 (cPLA2) was cloned from U937 cells and polymorphonuclear leukocytes (PMNLs) while a naturally occurring variant of cPLA2, which lacks residues Val473-Ala749 but has a C-terminal extension of ILMNLSEYMLWMSKVKRFM (DcPLA2) was cloned from PMNLs and mononuclear leukocytes. We were unable to clone DcPLA2 from U937 cells. When cPLA2 and DcPLA2 were expressed in insect cells, both proteins were detected in cell lysates by SDS/PAGE as single bands of apparent molecular masses 100 kDa and 57 kDa, respectively. Full-length cPLA2 was phosphorylated stoichiometrically by p42 mitogen-activated protein (MAP) kinase in vitro at a similar rate to other physiological substrates of this protein kinase and the major site of phosphorylation was identified by amino acid sequencing as Ser505. [32P]Ser(P)505 in cPLA2 was only dephosphorylated at a slow rate by mammalian tissue homogenates. Protein phosphatases 2A, 2B and 2C all contributed significantly to the overall dephosphorylation of cPLA2. The phosphorylation of cPLA2 by p42 MAP kinase correlated with an approximately 1.5-fold increase in specific enzyme activity which was reversed by dephosphorylation.

Antiamphiphysin antibodies with small‐cell lung carcinoma and paraneoplastic encephalomyelitis

Paraneoplastic encephalomyelitis developed as the presenting feature of small-cell lung carcinoma in 3 patients. Two patients with paraneoplastic encephalomyelitis manifested predominantly as subacute sensory neuronopathy did not improve after prednisone treatment and chemotherapy. The third patient had severe axial and limb rigidity and myoclonus, which partially improved after chemotherapy and treatment with intravenous immunoglobulin and prednisone. Serum from each patient immunocytochemically stained the neuropil and to a lesser degree the neuronal cytoplasm in human cerebral and cerebellar cortex. On immunoblots of human neuronal extracts, each patient's serum contained high-titer IgG antibodies reacting with a protein band of apparent molecular mass 125 kd. This autoantibody pattern is indistinguishable from antibodies recently identified in several women with breast carcinoma and stiff-man syndrome. Screening of a human brain complementary DNA expression library with patient serum yielded clones whose sequence is identical to that of the synaptic vesicle-related protein amphiphysin. Reverse transcriptase-polymerase chain reaction demonstrated expression of amphiphysin in 8 of 10 small-cell lung carcinomas and in 5 of 14 breast carcinomas. These observations highlight the clinical and serological heterogeneity of paraneoplastic central nervous system disorders: Patients with a given clinical syndrome may have different antineuronal antibodies, and patients with a given autoantibody specificity have differing clinical presentations.

Characterization of Bovine Endothelial Nitric Oxide Synthase Expressed inE. coli

Bovine endothelial constitutive nitric oxide synthase (eNOS) was expressed inE. colias a soluble, catalytically active enzyme using the pCW expression vector coexpressed with a plasmid, pGroELS, encoding the chaperonins groEL and groES. TheE. coliBL21 cultures reproducibly synthesized 6-10 mg of recombinant enzyme per liter of culture. The eNOS protein was purified using 2′5′-ADP Sepharose 4B and appeared as a single band of apparent molecular mass 135 kDa on SDS/PAGE. The recombinant resting enzyme is predominantly high spin with an absorbance maximum at 406 nm. The dithionite-reduced, CO-bound form shows an absorbance maximum at 444 nm. The spectral properties of recombinant eNOS fromE. coliare identical to those observed with eNOS from stably transfected HEK 293 cells or from baculovirus expression systems. Enzymatic activity of eNOS fromE. coliranged between 68-135 nmol product formed/min/mg at 25°C, using hemoglobin-NO capture or L-citrulline formation assays. The enzyme is replete with heme and flavins and both activity and [3H]-nitroarginine binding were largely dependent on tetrahydrobiopterin. The heterologous expression of eNOS offers a number of advantages over tissue sources of the protein.

Characterisation of a developmentally related polypeptide with glutelin solubility characteristics from Lupinus albus L.

Proteins from Lupinus albus L. cv. Rio Maior seeds were fractionated according to solubility criteria. Patterns of concanavalin A (ConA)-binding polypeptides from the different classes, albumins, globulins, glutelins and prolamins, were established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two bands of apparent molecular masses of 29 and 23.5 kDa with glutelin solubility characteristics bound the lectin. The 23.5-kDa band was separated by two-dimensional electrophoresis into two components: one glycosylated and heterogeneous with an isoelectric point of approx. 10 (designated as G23) and another, not detected with ConA, precipitating in the first dimension. The amino acid and hexosamine analysis of G23 showed that it is particularly rich in Gly (11.2%), Glx (10.0%), Ser (9.0%), Leu (8.2%), Asx (7.5%), and Pro (6.7%) and that it has a considerable content of the sulphur-containing amino acids Met (2.0%) and Cys (5.8%) and contains glucosamine. The determined N-terminal amino acid sequence of G23 was: 1KG(R)V5KGTGD10(T)PXXV15XLY(N)R20T, and this had no significant similarity to any of the amino acid sequences contained in the data bank SWISS-PROT 26. The glycoprotein G23 was completely deglycosylated with peptide-N-glycosidase F, yielding a homogeneous 21-kDa polypeptide composed of approximately 191 amino acids. The structures of the major N-linked neutral oligosaccharides of G23, determined by exoglycosidase sequencing, were as follows: Man alpha 2Man alpha 6(Man alpha 3) Man alpha 6(Man alpha 2Man alpha 2Man alpha 3)Man beta 4GlcNAc beta 4 GlcNAc (13%); +/- Man alpha 2Man alpha 6(Man alpha 3)Man alpha 6(+/- Man alpha 2 Man alpha 2 Man alpha 3)Man beta 4GlcNAc beta 4GlcNAc (29%); Man alpha 6(Man alpha 3) Man alpha 6(Man alpha 2Man alpha 3)Man beta 4GlcNAc beta 4GlcNAc (13%); Man alpha 6(Man alpha 3)Man alpha 6(Man alpha 3)Man beta 4GlcNAc beta 4GlcNAc (16%); Man alpha 6(Man alpha 3)(Xyl beta 2)Man beta 4GlcNAc beta 4GlcNAc (28%). Changes in G23 abundance during seed development, germination and seedling growth were monitored with a specific antibody. The glycoprotein G23 started to accumulate appreciably during seed formation between the 40th and the 50th days after anthesis and was detected following seed imbibition, until the 9th day in cotyledons, the 2nd day in roots and the 4th day in hypocotyls and leaves.

Nitric oxide synthase in the hypothalamic suprachiasmatic nucleus of rat: evidence from histochemistry, immunohistochemistry and Western blot; and colocalization with VIP

Nitric oxide (NO) is a neuroactive substance of high potency. Physiological results revealed the involvement of NO in circadian regulation of rats. Since neuronal structures containing NO-synthase (NOS) were previously not found in the circadian oscillator, the hypothalamic suprachiasmatic nucleus (SCN), in this species but are present in the hamster, we investigated the distribution of NO-producing structures in the rat SCN by Western blot analysis, immunohistochemistry of NOS, and by histochemistry (NADPH-diaphorase (NADPH-d) activity of NOS). Western blot analysis of SCN homogenates from rat (and, for comparison, hamster) showed a NOS-like immunoreactive (-LI) protein band of apparent molecular mass of 150 kDa, consistent with the neuronal NOS molecule. In the rat SCN, perikarya exhibiting NADPH-d staining or NOS-LI with a complete overlapping of both were found. Double-immunofluorescence experiments revealed that NOS cells are a subgroup of the neuronal SCN population that is characterized by immunoreactivity to vasoactive intestinal polypeptide. These data provide evidence for the existence of neuronal nitric oxide synthase in the rat SCN and may explain the involvement of NO in the mediation of photic information.

Purification and characterization of a fatty acid-activated protein kinase (PKN) from rat testis.

PKN, a novel protein kinase with a catalytic domain homologous to that of the protein kinase C (PKC) family and unique N-terminal leucine-zipper-like sequences, was identified by molecular cloning from a human hippocampus cDNA library [Mukai and Ono (1994) Biochem. Biophys. Res. Commun. 199, 897-904]. Recently we partially purified recombinant PKN from COS7 cells transfected with the cDNA construct encoding human PKN, and demonstrated that the recombinant PKN was activated by unsaturated fatty acids and limited proteolysis [Mukai, Kitagawa, Shibata et al. (1994) Biochem. Biophys. Res. Commun. 204, 348-356]. The present work has focused on the further purification and characterization of PKN from native rat tissue. Immunochemical measurement revealed that PKN was found in every tissue, and was especially abundant in testis, spleen and brain; subcellular fractionation of rat brain showed that half of the PKN was localized in the soluble cytosolic fraction. PKN was purified approx. 8000-fold to apparent homogeneity from the cytosolic fraction of rat testis by DEAE-cellulose chromatography, ammonium sulphate fractionation and chromatography on butyl-Sepharose, heparin-Sepharose, Mono Q and protamine-CH-Sepharose. The enzyme migrates as a band of apparent molecular mass 120 kDa. Using serine-containing peptides based on the pseudosubstrate sequence of PKC-delta as phosphate acceptors, the kinase activity was stimulated several-fold by 40 microM unsaturated fatty acids or by detergents such as 0.04% sodium deoxycholate and 0.004% SDS. In the absence of modifiers, protamine sulphate, myelin basic protein and synthetic peptides based on the pseudosubstrate site of PKCs or ribosomal S6 protein were good substrates for phosphorylation by the kinase. In the presence of 40 microM arachidonic acid the kinase activity of PKN for these phosphate acceptors was increased 2-18-fold. The autophosphorylation activity of purified PKN was partially inhibited by pretreatment with alkaline phosphatase. These properties appear to distinguish PKN from many protein kinases isolated previously.

Expression of a tomato cDNA coding for phytoene synthase in Escherichia coli, phytoene formation in vivo and in vitro, and functional analysis of the various truncated gene products.

Full length and truncated cDNA expression constructs of the phytoene synthase (psy) gene from tomato have been ligated into a pUC8 cloning vector. One of the truncated constructs was introduced into Escherichia coli carrying the Erwinia uredovora GGPP synthase gene. This transformant produced 15,15'-cis-phytoene, which was identified on the basis of its UV and IR spectral data, from geranylgeranyl diphosphate. The function of this gene product was further confirmed by in vitro assay using cell-free extract of E. coli harboring the construct. On transformation with the above constructs together with a plasmid containing the carotenoid gene cluster from E. uredovora devoid of the phytoene synthase (crtB) gene, yellow, carotenoid-containing, E. coli colonies were produced. The amounts of carotenoids synthesized by the transformed cells, related to the steady-state levels of psy mRNA, varied depending upon the psy constructs. The full-length psy clone produced 16-fold less carotenoids per unit amount of RNA than cells containing phytoene synthase without the first 114 N-terminal amino acids. Removal of further amino acids from the N-terminus caused a large decrease in carotenogenesis. A Western blot of ripe fruit stroma with a monoclonal antibody raised against phytoene synthase revealed a single protein band of apparent molecular mass 38 kDa. Based upon this immunological evidence, we conclude that the size of the transit peptide of phytoene synthase from ripe tomato fruit is approximately 9 kDa, corresponding to about 80 amino acid residues.(ABSTRACT TRUNCATED AT 250 WORDS)

A neutrophil migration-inducing lectin from Artocarpus integrifolia.

A neutrophil migration-inducing protein has been isolated from the saline extract of Artocarpus integrifolia seeds by successive sugar affinity chromatography steps during which the protein was not absorbed by D-galactose resin, and then was absorbed to and eluted from D-mannose resin by 0.1 M D-mannose. Gel filtration on Superdex 75 HR indicated a molecular mass of 52 kDa when 0.1 M D-mannose was present in the elution buffer. A single band of apparent molecular mass of 13 kDa was demonstrable by SDS-PAGE only after heating, both in the presence and absence of reducing agent, suggesting that the molecule is a tetramer formed by the noncovalent association of 13 kDa chains. Isoelectric forms corresponding to isoelectric points of 4.0, 4.2, 5.0, and 5.2 were demonstrable by isoelectric focusing-PAGE, and four active forms having the same isoelectric points were separated by chromatofocusing. The minimal m.w. calculated from amino acid analysis data was 13,193. The protein, denoted KM+, stimulated neutrophil migration in the rat peritoneal cavity assay in a dose-related manner in the range of 1 to 300 micrograms per rat. The dose-response curve of the in vitro chemotactic activity of KM+ was bell shaped and its ascending limb was dose dependent in the range of 1 ng to 10 micrograms/well. D-Mannose (0.1 M) inhibited the in vitro (80%) and in vivo (60%) neutrophil migration-inducing activities of KM+ and also its hemmaglutinating activity. The chemotactic activity was shown to be caused by haptotaxis rather than chemokinesis. The physical and biologic properties of KM+ suggest that this lectin may attract neutrophils by a mechanism involving a haptotactic gradient as has been proposed for IL-8. KM+ might be used as tool to study protein-carbohydrate interactions during neutrophil migration through the extracellular matrix.

Purification to homogeneity of an active opioid receptor from rat brain by affinity chromatography.

Active opioid binding proteins were solubilized from rat brain membranes in high yield with sodium deoxycholate in the presence of NaCl. Purification of opioid binding proteins was accomplished by opioid antagonist affinity chromatography. Chromatography using the delta-opioid antagonist N,N-diallyl-Tyr-D-Leu-Gly-Tyr-Leu attached to omega-aminododecyl-agarose (Affi-G) (procedure A) yielded a partially purified protein that binds selectively the delta-opioid agonist [3H]Tyr-D-Ser-Gly-Phe-Leu-Thr ([3H]DSLET), with a Kd of 19 +/- 3 nM and a Bmax of 5.1 +/- 0.4 nmol/mg of protein. Subsequently, Lens culinaris agglutinin-Sepharose 4B chromatography of the Affi-G eluate resulted in isolation of an electrophoretically homogeneous protein of 58 kDa that binds selectively [3H]DSLET with a Kd of 21 +/- 3 nM and a Bmax of 16.5 +/- 1.0 nmol/mg of protein. Chromatography using the nonselective antagonist 6-aminonaloxone coupled to 6-aminohexanoic acid-Sepharose 4B (Affi-NAL) (procedure B) resulted in isolation of a protein that binds selectively [3H]DSLET with a Kd of 32 +/- 2 nM and a Bmax of 12.4 +/- 0.5 nmol/mg of protein, and NaDodSO4/PAGE revealed a major band of apparent molecular mass 58 kDa. Polyclonal antibodies (Anti-R IgG) raised against the Affi-NAL protein inhibit the specific [3H]DSLET binding to the Affi-NAL eluate and to the solubilized membranes. Moreover, the Anti-R IgG inhibits the specific binding of radiolabeled Tyr-D-Ala-Gly-N-methyl-Phe-Gly-ol (DAMGO; mu-agonist), DSLET (delta-agonist), and naloxone to homogenates of rat brain membranes with equal potency. Furthermore, immunoaffinity chromatography of solubilized membranes resulted in the retention of a major protein of apparent molecular mass 58 kDa. In addition, immunoblotting of solubilized membranes and purified proteins from the Affi-G and Affi-NAL matrices revealed that the Anti-R IgG interacts with a protein of 58 kDa.

Gelatinase activity of exoantigens from virulent and non-virulent isolates ofParacoccidioides brasiliensis

Differences in the occurrence of components with gelatinase activity were detected among four isolates of Paracoccidioides brasiliensis: Pb339 and Pb18 (highly virulent), and Pb265 and Pb18AV (very low virulence). Culture filtrates from these isolates were electrophoresed in substrate gels and tested for gelatinase activity. Pb339 showed three enzyme bands of apparent molecular masses: 43, 53 and 78 kDa; Pb18 had two bands, one at 59 kDa and another with molecular mass higher than 78 kDa. Isolate Pb18AV showed only one band at 78 kDa and Pb265 exhibited a component of molecular mass which failed to enter the separating gel.