bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Chemical Inducers of Systemic Acquired Resistance (SAR) for the Management of Late Blight Disease of Potato
Authors: Peerzada S. H. , Viswanath H. S. , Bhat K. A.
Published: September 2020

Late blight of potato is one of the most devastating diseases with great economic importance. Among several disease management strategies, ISR (Induced systemic resistance) plays an important role in checking the disease spread. So, in the present study, nine different SAR chemical inducers viz. Phosphoric acid, Salicylic acid, Naphthalene acetic acid(NAA), Benzoic acid, Benzothiadiazole, Dichloro-iso nicotinic acid (INA) and Kinetin were evaluated at 0.05% (C1), 0.10% (C2) and 0.15% (C3) concentrations, whereas Calcium chloride and Ascorbic Acid at 3.5% (C1), 5.0% (C2), 6.5% (C3) and 1.5% (C1), 2.0% (C2), 2.5% (C3) respectively at three different concentrations each, along with positive and negative checks of standard fungicide metalaxyl 8+ macozeb 64 WP @0.25% and control(water) respectively by spraying them at 2-3 compound leaf stage of plants which were challenged by P. infestans inoculations five days later in pots to assess disease incidence and intensity which were recorded at weekly intervals of four stages (stage I-IV). It was found that the foliar spray with benzothiadiazole (BTH) @ 0.10 to 0.15% was best in delaying the appearance of first symptoms of the disease by 11 days followed by salicylic acid@ 0.10 to 0.15% and ascorbic acid @ 2.5% which delayed the symptom appearance by 9 days, whereas the standard fungicidal spray of metalaxyl 8 + mancozeb 64 WP at the recommended concentration of 0.25% delayed the symptom appearance by only 8 days when compared to water sprayed check. It was also found that on an average, BTH sprays completely arrested the late blight development (0% intensity) followed by salicylic acid, INA and ascorbic acid sprays exhibiting 0.46-0.74% mean blight intensity compared to 2.00 and 6.28 percent intensity recorded, respectively, on metalaxyl 8 + mancozeb 64 WP and water-sprayed plants one week after first appearance of disease in control pots (stage I). These treatments with chemical inducers showed an increase in the activity of peroxidases and polyphenol oxidases in the infected potato leaves as a result of SAR activity at all stages (stage I-IV). Average maximum peroxidase activity of 19.01-20.66 mg and polyphenol oxidase activity of 2.70-2.89 mg were recorded in the potato leaves during stage-I, sprayed with either BTH, benzoic acid, phosphoric acid or salicylic acid as compared to only (16.78 mg and 2.28 mg), (4.66 mg and 1.36 mg) recorded in (metalaxyl 8 + mancozeb 64 WP) and water-sprayed check respectively. The highest concentrations of all the test chemicals, in general, showed increased biochemical activity thereby yielding lesser blight intensity compared to their lower concentrations.
What Strategies for the Sustainable Management of Public Debts in Sub-Saharan Africa?
Authors: Bikoué Siméon Maxime , Penn Collins Chi
Published: September 2020

Aim/Method: This article examines the different strategies required for the sustainability of sub-Sahara Africa’s external debt by applying the Simonsen criterion[1] and the conditions of the Harrod-Domar debt and growth model.

Results/Conclusion: We then suggest that for debt to be sustainable the financial ratios have to be respected. So the effective servicing of the external debt in Sub-Saharan Africa requires that the expenses incurred in reducing poverty should be known. If the difference between the net returns and the expenses incurred in fighting against poverty is negative this reduces the burden of the debt. Finally, we recommend that Sub-Saharan African countries should use a combination of strategies based on sustainable development, financial resources of the government, and regulatory and institutional norms to manage their debts sustainably.
Antioxidant Enhancing Effect of Azadirachta indica A. Juss. Leaf Fractionated Extracts on Naja nigricollis Reinhardt Venom in Albino Rats
Authors: Sani Ibrahim , Umar Rabi’u Aliyu , Hassan Sanusi Wara , Faruq Umar Zaki , Bello Fatima
Published: September 2020

The lethality of snake venom is mainly attributed to its phospholipase A2 component that hydrolyzes cellular phospholipids, leading to the release of arachidonic acid that generates potentially toxic reactive oxygen species (ROS). Imbalance between excessive generation and poor removal of ROS causes lipid peroxidation leading to cellular damage. Hence, this research was aimed at evaluating the antioxidant-enhancing effect of Azadirachta indica leaf fractionated extracts on Naja nigricollis venom in albino rats. A. indica leaf was collected, authenticated and extracted using 95% methanol followed by fractionation using hexane and ethyl acetate. Ferric reducing antioxidant power assay was used for the in vitro test, while, in vivo experiments were conducted using Albino rats. The in vitro antioxidant effect of the hexane and ethyl acetate fractions presented ferric reducing power of 68.80 ± 1.40% and 71.54 ± 2.12% respectively. This are closely related to those of ascorbic acid (78.50 ± 2.80%) and α-tocopherol (75.00 ± 1.85%). The results of the in vivo tests indicated that a single injection (0.195 mg/kg b. wt.) of N. nigricollis venom caused significant (P<0.05) elevation of hepatic and renal ROS levels (7 and 8 folds respectively) with a concomitant increase in lipid peroxidation (LPO) compared to the control group. The ROS levels were decreased significantly leading to the decrease in the level of LPO in the envenomed rats treated with the hexane and ethyl acetate fractions compared to the venom control. The treatments significantly (P<0.05) increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in both the hepatic and renal homogenates compared to the venom control. The degree of protection against LPO by reducing the levels of ROS as well as increasing the activities of the antioxidant enzymes has significantly (P<0.05) increased when combine treatment of standard antivenin and any of the hexane or ethyl acetate fractions was considered compared to when each of them was used alone. Based on these findings, it has been established that, the tested extracts have antioxidant as well as antioxidant-enhancing effects against the oxidative toxicity of N. nigricollis venom.
Health Professionals Dynamic Role Amid COVID-19: Nursing Perspectives
Authors: Ramaiah Pushpamala , Tayyib Nahla A. , Alsolami Fatmah J. , Lindsay Grace M. , Asfour Hayam I.
Published: September 2020

A novel coronavirus (COVID-19) is a newly discovered virus in 2019 in Wuhan, China.           Globally around the world, healthcare professionals (HCP), including nurses, are the                    front line health workers (FHW), considered as a vital member of the team trying to                      save several people's lives. Although leading health organizations and scientific                      papers consistently addressed the HCP challenging role concerning multidisciplinary       approaches and support systems, along with evidence-based research implications for        delivering the best possible quality care, this review resulted in four primary categories,              such as challenges, domains, support systems (code of ethics), and evidence-based            synthesis of health policy.  A step further, this article will detail the tremendous role of               brave healthcare workers, including nurses and pharmacists who proved themselves as              health warriors, along with the key issues about the nurses' perspectives on the impact of COVID-19, and to debunk the mixed messages what is being reported every day is a virtual drive for nurses focusing on the significant domains of nursing practices as a motivating factor amid COVID-19.
Release of immunoreactive atrial natriuretic factor from the isolated perfused rat lung
Authors: Gutkowska Jolanta , Cantin Marc , Genest Jacques , Sirois Pierre
Published: July 2002

The secretion of ANF by the rat lung was demonstrated in the present study. Four forms of immunoreactive ANF were detected in rat lung homogenates, including the 126 amino acid prohormone but only a low molecular mass peptide was released during lung perfusion. The released ANF inhibited forskolin‐stimulated aldosterone secretion from rat zona glomerulosa cell suspensions, and this biological effect was comparable to that of the synthetic C‐terminal part of the prohormone (Arg‐101—Tyr‐126).
Brain basic fibroblast growth factor stimulates the proliferation of rat neuronal precursor cells in vitro
Authors: Gensburger Claire , Labourdette Gérard , Sensenbrenner Monique
Published: July 2002

Neuronal cells from cerebral hemispheres of 13‐day‐old rat embryos were grown in a serum‐free culture medium for 48 h, 4 or 8 days. The neuronal precursor cells proliferate for 5 days. The addition of bovine brain basic fibroblast growth factor stimulates their proliferation as determined by measurement of [121I]‐iododeoxyuridine incorporation and by autoradiographic analysis after [3H]thymidine incorporation. The proliferating responsive cells were characterized as neurons by immunostaining against neurofilament proteins. Five other growth factors tested were without effect on the proliferative activity of these neuronal cells. The present results show that bFGF is mitogenic in vitro for rat neuronal precursor cells of the central nervous system.
Tumour necrosis factor is a compact trimer
Authors: Wingfield Paul , Pain Roger H. , Craig Stewart
Published: July 2002

Recombinant produced human tumour necrosis factor (TNF) has been studied to characterise the subunit structure of the protein. TNF is shown to be a trimer M
r 52000 in which the subunits are associated in a compact, triangular form. In secondary structure it belongs to the all‐β class of proteins. It has high thermodynamic stability and the unfolded subunits can fold and associate spontaneously to form native, biologically active TNF.
Role of endopeptidase‐24.11 in the inactivation of atrial natriuretic peptide
Authors: Kenny A.John , Stephenson Sally L.
Published: July 2002

The circulating form of atrial natriuretic factor is a 28‐residue peptide containing a 17‐residue disulphide‐linked ring. It has important actions on the kidney, largely on its haemodynamics, and at other sites including the adrenal cortex and CNS. It has a short half‐life in vivo and is rapidly inactivated when incubated with kidney microvillar membranes. Of the battery of peptidases present in that membrane, only one, endopeptidase‐24.11, is responsible for initiating the attack, and this commences with hydrolysis of the Cys7‐Phe8 bond within the ring. Hydrolysis at this and other points has been shown to inactivate the peptide and this information has pointed the way to the synthesis of resistant analogues.
Primary structure of rat chromogranin A and distribution of its mRNA
Authors: Iacangelo Anna , Okayama Hiroto , Eiden Lee E.
Published: July 2002

The primary structure of rat chromogranin A has been deduced from a rat adrenal cDNA clone. A comparison of rat and bovine chromogranin A reveals several similar features: clusters of polyglutamic acid, similar amino acid composition, position of seven of 10 pairs of basic amino acids, identical placement of the only two cysteine residues, a highly conserved N‐ and C‐terminus, and a sequence homologous to porcine pancreastatin 1–49 [(1986) Nature 324, 476–478]. Unique features of rat chromogranin A are an eicosaglutamine sequence and two potential N‐linked glycosylation sites. Chromogranin A mRNA is detectable in adrenal medulla, anterior pituitary, cerebral cortex, and hippocampus, as well as tumor cell lines derived from pancreas, pituitary, and adrenal medulla.
Antithrombin Cambridge, 384 Ala to Pro: A new variant identified using the polymerase chain reaction
Authors: Perry David J. , Harper Paul L. , Fairham Stuart , Daly Martina , Carrell Robin W.
Published: July 2002

An antithrombin III variant was identified in the plasma of a female patient with a history of recurrent thromboses. The variant was shown to have normal antigenic levels but reduced heparin and progressive inhibitory activity consistent with an abnormality affecting function at the reactive centre. Polymerase chain reaction amplification of exon 6 of the gene with direct sequencing showed a point mutation resulting in the substitution of a proline for alanine at position 384. This substitution will predictably alter the conformation of the peptide loop containing the reactive centre of the molecule.
Presence of fructokinase in pancreatic islets
Authors: Malaisse Willy J. , Malaisse-Lagae Francine , Davies Dewi R. , Van Schaftingen Emile
Published: July 2002

Homogenates of rat pancreatic islets that had been heated for 5 min at 70°C to inactive hexokinases, catalysed the ATP‐dependent phosphorylation of D‐fructose. This reaction was dependent on the presence of K+ and was inhibited by D‐tagatose although not by D‐glucose or D‐glucose 6‐phosphate. The phosphorylation product was identified as fructose 1‐phosphate through its conversion to a bisphosphate ester by Clostridium difficile fructose 1‐phosphate kinase. These findings allowed the conclusion that fructokinase (ketohexokinase) was responsible for this process. Similar results were observed with tumoral insulin‐producing cells (RINm5F line). Fructokinase may account for a large share of fructose phosphorylation in intact islets, particularly in the presence of D‐glucose.
IAPP/amylin gene transcriptional control region: evidence for negative regulation
Authors: Mosselman S. , Höppener J.W.M. , de Wit L. , Soeller W. , Lips C.J.M. , Jansz H.S.
Published: July 2002

Aberrant expression of the islet amyloid polypeptide (IAPP) gene might be involved in the pathogenesis of nun‐insulin‐dependent diabetes mellitus (NIDDM). Here, we report that IAPP promoter‐luciferase constructs revealed tissue‐specific activity. This activity was not mediated by cAMP. Sequential 5' deletions of the IAPP promoter caused a progressive derepression of the IAPP gene promoter in IAPP‐producing cells. Comparison of the nucleotide sequence of the IAPP promoter with that of the insulin promoter (both active in pancreatic β‐cells) reveals two sequence elements of putative importance: an insulin enhancer‐like sequence and an element which corresponds to a protected domain in rat insulin I gene promoter footprint experiments.
Locustatachykinin I and II, two novel insect neuropeptides with homology to peptides of the vertebrate tachykinin family
Authors: Schoofs Liliane , Holman G.Mark , Hayes Timothy K. , Nachman Ronald J. , De Loof Arnold
Published: July 2002

Two myotropic peptides termed locustatachykinin I (Gly‐Pro‐Ser‐Gly‐Phe‐Tyr‐Gly‐Val‐Arg‐NH2) and locustatachykinin II (Ala‐Pro‐Leu‐Ser‐Gly‐Phe‐Tyr‐Gly‐Val‐Arg‐NH2) were isolated from brain‐corpora cardiaca‐corpora allata‐suboesophageal ganglion extracts of the locust, Locusta migratoria. Both peptides exhibit sequence homologies with the vertebrate tachykinins. Sequence homology is greater with the fish and amphibian tachykinins (up to 45%) than with the mammalian tachykinins. In addition, the intestinal myotropic activity of the locustatachykinins is analogous to that of vertebrate tachykinins. The peptides discovered in this study may just be the first in a whole series of substances from arthropod species to be identified as tachykinin family peptides. Moreover, both chemical and biological similarities of vertebrate and insect tachykinins substantiate the evidence for a long evolutionary history of the tachykinin peptide family.
Tautomycin from the bacterium Streptomyces verticillatus
Authors: MacKintosh Carol , Klumpp Susanne
Published: July 2002

Tautomycin inhibited the catalytic subunits of protein phosphatase‐1 (K
i
app = 0.16 nM) more potently than protein phosphatase 2A (K
i
app = 0.4 nM), and the native forms of these enzymes in mammalian, protozoan and plant extracts were inhibited in a similar manner. Protein phosphatase 2B was inhibited 10 000‐fold less potently, while two other phosphatases and six protein kinases were unaffected at 10 μM. Okadaic acid prevented the binding of tautomycin to protein phosphatase 2A, indicating a common binding site for both inhibitors. The different relative potencies of tautomycin and okadaic acid for protein phosphatases 1 and 2A suggest that parallel use of both inhibitors may help to identify physiological substrates for each enzyme.
Identification of a low‐Mr acidic nuclear protein as prothymosin α
Authors: Palvimo Jorma , Linnala-Kankkunen Annikka
Published: July 2002

We have purified to homogeneity a 15‐kDa perchloric acid (PCA)‐soluble protein from rat thymus nuclei. This highly acidic protein showed a M
r, of ca. 30 kDa in acetic acid/urea gels, probably due to oligomer formation. Sequence analysis of internal tryptic and thennolytic peptides revealed that the purified protein is, in fact, prothymosin α, a very hydrophilic polypeptide, which has been previously classified as a thymic or immunomodulating hormone. We found that prothymosin α is a rather abundant nuclear protein in rat thymus; its concentration is comparable to that of a well‐characterized nonhistone protein HMG‐14. The subcellular localization and physicochemical properties of prothymosin α suggest that its function is related to those of other long polyacidic regions containing nuclear proteins.
Expression and cell membrane localization of rat M3 muscarinic acetylcholine receptor produced in Sf 9 insect cells using the baculovirus system
Authors: Vasudevan Subhash , Reiländer Helmut , Maul Gabi , Michel Hartmut
Published: July 2002

A recombinant baculovirus bearing the cDNA coding for the rat muscarinic acetylcholine receptor subtype M3 placed under the control of the Autographa californica nuclear polyhedrosis virus polyhedrin gene promoter, was constructed. Polymerase chain reaction screening was used to identify the recombinant baculovirus. Northern blot analysis of total RNA from insect cells infected with the recombinant baculovirus indicated that the transcripts were abundant. Binding assays carried out with the muscarinic antagonist [3H]quinuclidinyl benzilate indicated that more than 1 × 106 receptors were produced per cell. Immunofluorescence microscopy showed that the receptor is located on the cell surface.
Endothelium‐derived relaxing factor is a nitrosyl iron complex with thiol ligands
Authors: Vanin Anatoly F.
Published: July 2002

A hypothesis is put forward on the nature of the endothelium‐derived relaxing factor (EDRF) which is released from vascular endothelial cells by acetylcholine, bradykinin and other agonists. It is suggested that EDRF is a nitrosyl iron complex with low‐molecular thiol ligands, most probably with cysteine. Its active principle is nitric oxide (NO). This free radical is stabilized by inclusion into the iron complex, which promotes NO transfer within the cell and between cells. Subsequent release of NO from these complexes results from thiol group oxidation.
Enhanced cellular uptake of biotinylated antisense oligonucleotide or peptide mediated by avidin, a cationic protein
Authors: Pardridge William M. , Boado Ruben J.
Published: July 2002

The cellular uptake of a model antisense oligonucleotide complementary to 21 bases of the bovine GLUT‐1 glucose transporter mRNA and a model vasopressin peptide that were biotinylated, was markedly stimulated by the presence of avidin, a cationic protein. Conversely, the bacterial homologue of avidin, streptavidin, which is a slightly acidic protein, did not facilitate cellular uptake. The avidin‐mediated uptake of biotinylated derivatives was competitively inhibited by another cationic protein, protamine, with a K
i or 5 μg/ml; was saturable, temperature‐ and time‐dependent; and was associated with endocytosis, The use of the avidin‐biotin system provides a new approach to increasing the cellular uptake of antisense oligonucleotides or peptides.
Molecular basis for the insensitivity of the Monarch (Danaus plexippus) to cardiac glycosides
Authors: Holzinger Ferdinand , Frick Christoph , Wink Michael
Published: July 2002

The Monarch (Danaus plexippus) sequesters cardiac glycosides for its chemical defence against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera, such as Manduca sexta and Creatonotos transiens are sensitive and intoxicated by ouabain. Ouiabain inhibits the Na+,K+‐ATPase by binding to its α‐subunit. We have amplified and cloned the DNA sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain‐sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of about 12 amino acids. This change may explain the ouabain insensitivity.
A human synaptic vesicle monoamine transporter cDNA predicts posttranslational modifications, reveals chromosome 10 gene localization and identifies TaqI RFLPs
Authors: Surratt Christopher K. , Persico Antonio M. , Yang Xiao-Dong , Edgar Stephanie R. , Bird Geoffrey S. , Hawkins Anita L. , Griffin Constance A. , Li Xiang , Jabs Ethylin W. , Uhl George R.
Published: July 2002

A human vesicular monoamine transporter cDNA has been identified by screening a human brainstem library using sequences from the rat brain synaptic vesicle monoamine transporter (SVMT) [(1992) Cell 70, 539‐551; (1992) Proc. Natl. Acad. Sci. USA 89, 10993‐10997]. The hSVMT shares 92% amino acid identity with the rat sequence, but displays one less consensus site for asparagine N‐linked glycosylation and one more consensus site for phosphorylation by protein kinase C. The human SVMT gene maps to chromosome 10q25 using Southern blotting analysis of human/rodent hybrid cell lines and fluorescent in situ hybridization approaches. The cDNA, and a subclone, recognize TaqI polymorphisms that may prove useful to assess this gene's involvement in neuropsychiatric disorders involving monoaminergic brain systems.
Expression of α,βA and βB subunits of inhibin or activin and follistatin in rat pancreatic islets
Authors: Ogawa Kenji , Abe Keiko , Kurosawa Nobuyuki , Kurohmaru Masamichi , Sugino Hiromu , Takahashi Michio , Hayashi Yoshihiro
Published: July 2002

We first detected the mRNA expression of follistatin and three subunits of inhibin/activin in rat pancreatic islets by reverse transcription‐polymerase chain reaction (RT‐PCR). Immunohistochemistry using anti‐follistatin serum (against residues 123–134) revealed that follistatin was localized only in insulin‐producing B cells. Although the βA subunit was detectable in the islets, the immunostainable cell types were completely different with two βA antisera, i.e. anti‐βA (1–1O)‐Tyr stained B cells, while anti‐βA (87–99) stained glucagon‐producing A cells. This inconsistent immunoreactivity was probably related to follistatin binding to β subunits of inhibin/activin. This study indicates that follistatin and inhibin/activin in the islet serve as paracrine or autocrine modulators in the endocrine pancreas.
A constitutive form of heat‐shock protein 70 is located in the outer membranes of mitochondria from rat liver
Authors: Lithgow Trevor , Ryan Michael , Anderson Robin L. , Høj Peter B. , Hoogenraad Nicholas J.
Published: July 2002

HSP73, the constitutive form of heat‐shock protein 70, has been implicated in the translocation of preproteins across the mitochondrial membranes, being required for maintaining mitochondrial preproteins in an import competent conformation. Here we report that highly purified mitochondrial outer membranes contain a protein indistinguishable from HSP73 as a tightly associated peripheral component of the membrane. This membrane form of HSP73 was photolabelled with [α‐32P]ATP and could be released from the outer membrane with sodium carbonate, but not after incubation of the membranes with salt or with ATP. A sensitive immunoassay with an anti‐HSP73 monoclonal antibody, revealed the association of HSP73 with mitochondrial outer membrane vesicles at a level similar to that of preprotein import receptors.
Molecular cloning of PARP (proline/arginine‐rich protein) from human cartilage and subsequent demonstration that PARP is a fragment of the NH2‐terminal domain of the collagen α2(XI) chain
Authors: Zhidkova Natalia I. , Brewton Randolph G. , Mayne Richard
Published: July 2002

We report the molecular cloning of a proline/arginine‐rich protein (called PARP) from human cartilage using the polymerase chain reaction (PCR) and degenerate oligonucleotides based on the previously published amino acid sequence of bovine PARP [1]. Subsequently, a reverse transcription‐polymerase chain reaction (RT‐PCR) was performed with poly(A)‐rich RNA from human cartilage using a sense oligonucleotide derived from PARP and an anti‐sense oligonucleotide derived from the known sequence of the human collagen α2(XI) chain [2]. Nucleotide sequencing of the PCR product demonstrated that PARP is a fragment of the NH2‐terminal non‐collagenous (NC3) domain of the collagen α2(XI) chain.
Electrophoretic separation of developmental and adult rabbit skeletal muscle myosin heavy chain isoforms: Example of application to muscle denervation study
Authors: Janmot Chantal , d' Albis Anne
Published: July 2002

We present the separation by SDS gel‐electrophoresis of the six main myosin heavy chains (MHC) present in rabbit skeletal muscle. The separation of the four adult MHC (1, 2A, 2X/2D, 2B) was compared to that of the corresponding rat MHC as described by Talmadge and Roy [J. Appl. Physiol. 99 (1993) 2337‐2340]. We found that many rabbit muscles contained mainly one of the four MHC, in some cases the 2B MHC. In addition, we resolved the embryonic E and perinatal P developmental MHC, which should facilitate muscle differentiation and regeneration studies in the rabbit. An example of application to the study of muscle denervation is given.
Increase in activin βA mRNA in rat hippocampus during long‐term potentiation
Authors: Inokuchi Kaoru , Kato Akihiko , Hiraia Keiko , Hishinuma Fumio , Inoue Maki , Ozawa Fumiko
Published: July 2002

We have used mRNA differential display to isolate genes that are induced by neural activity in rat hippocampus. One of these encodes activin βA subunit. Convulsive seizure caused by kainate significantly induced the expression of activin βA mRNA. Furthermore high frequency stimulation (HFS) of perforant pathway, which produced a persistent long‐term potentiation (LTP) (> 10 h), caused a marked increase at 3 h in the level of activin βA mRNA at the dentate gyrus of urethane‐anesthetized rat. The increase was NMDA receptor‐dependent. By contrast the level of inhibin α mRNA was not changed following the induction of LTP. The results suggest a role for activin in maintenance of neural plasticity in the adult brain.
Isolation of the epithiospecifier protein from oil‐rape (Brassica napus ssp. oleifera) seed and its characterization
Authors: Bernardi Roberta , Negri Armando , Ronchi Severino , Palmieri Sandro
Published: July 2002

The epithiospecifier protein (ESP) is a myrosinase (MYR) cofactor, which is necessary to drive the MYR‐catalyzed hydrolysis of some specific glucosinolates towards the production of cyanoepithioalkanes instead of isothiocyanates and nitriles. ESP was isolated from Brassica napus seeds by anionic exchange and gel filtration chromatography. ESP showed a molecular weight of about 39 kDa and pI 5.3. The amino acid sequence of several tryptic peptides of ESP (accounting for about 50% of the total sequence) made it possible to establish the high similarity (81% identity) with a hypothetical 37 kDa protein (TrEMBL data base accession number Q39104) and several jasmonate‐inducible proteins from Arabidopsis thaliana. This observation suggests that ESP is likely to be involved in jasmonate‐mediated defence and disease resistance mechanisms.
Clostridium perfringens enterotoxin binds to the second extracellular loop of claudin‐3, a tight junction integral membrane protein
Authors: Fujita Kohji , Katahira Jun , Horiguchi Yasuhiko , Sonoda Noriyuki , Furuse Mikio , Tsukita Shoichiro
Published: July 2002

Claudins (claudin‐1 to ‐18) with four transmembrane domains and two extracellular loops constitute tight junction strands. The peptide toxin Clostridium perfringens enterotoxin (CPE) has been shown to bind to claudin‐3 and ‐4, but not to claudin‐1 or ‐2. We constructed claudin‐1/claudin‐3 chimeric molecules and found that the second extracellular loop of claudin‐3 conferred CPE sensitivity on L fibroblasts. Furthermore, overlay analyses revealed that the second extracellular loop of claudin‐3 specifically bound to CPE at the K
a value of 1.0×108 M−1. We concluded that the second extracellular loop is the site through which claudin‐3 interacts with CPE on the cell surface.
New molecular aspects of regulation of mitochondrial activity by fenofibrate and fasting
Authors: Casas François , Pineau Thierry , Rochard Pierrick , Rodier Anne , Daury Laetitia , Dauça Michel , Cabello Gérard , Wrutniak-Cabello Chantal
Published: July 2002

Fenofibrate and fasting are known to regulate several genes involved in lipid metabolism in a similar way. In this study measuring several mitochondrial enzyme activities, we demonstrate that, in contrast to citrate synthase and complex II, cytochrome c oxidase (COX) is a specific target of these two treatments. In mouse liver organelles, Western blot experiments indicated that mitochondrial levels of p43, a mitochondrial T3 receptor, and mitochondrial peroxisome proliferator activated receptor (mt‐PPAR), previously described as a dimeric partner of p43 in the organelle, are increased by both fenofibrate and fasting. In addition, in PPARα‐deficient mice, this influence was abolished for mt‐PPAR but not for p43, whereas the increase in COX activity was not altered. These data indicate that: (1) PPARα is involved in specific regulation of mt‐PPAR expression by both treatments; (2) fenofibrate and fasting regulate the mitochondrial levels of p43 and thus affect the efficiency of the direct T3 mitochondrial pathway.
DFNA5 (ICERE‐1) contributes to acquired etoposide resistance in melanoma cells
Authors: Lage Hermann , Helmbach Heike , Grottke Claudia , Dietel Manfred , Schadendorf Dirk
Published: July 2002

Resistance to drug treatment is a common observation in malignant melanoma. In order to analyze alterations in mRNA expression profiles associated with drug resistance in melanoma cells we previously established a panel of various drug‐resistant cell variants derived from the human melanoma line MeWo and compared the mRNA expression profiles by a differential display technique. By that approach it could be demonstrated that the expression level of a mRNA encoded by a gene found to be mutated in non‐syndromic hearing impairment, DFNA5 (ICERE‐1), was distinctly decreased in the 33‐fold etoposide‐resistant melanoma cell line MeWo ETO 1. To evaluate the hypothesis that a decrease in DFNA5 mRNA expression level contributes to the acquired etoposide resistance phenotype exhibited by MeWo ETO 1 cells, this drug‐resistant line was stably transfected with the DFNA5‐encoding cDNA. Transfected clones showed a 30–35% reduced etoposide susceptibility by comparing the IC25, IC50 and IC75 values of these clones with those displayed by the non‐transfected, etoposide‐resistant melanoma cell line MeWo ETO 1 and controls. Furthermore, etoposide exposure of stable DFNA5 transfectants resulted in an increase of caspase‐3‐mediated apoptotic events in DFNA5‐transfected clones in comparison to MeWo ETO 1 cells and controls. The data therefore demonstrate that a decrease in DNFA5 mRNA expression level is associated with an increased etoposide resistance in melanoma cells due to an elevated cellular susceptibility to trigger a caspase‐3‐depending signal pathway leading to programmed cell death.
Effect of human recombinant leptin on lipid handling by fully differentiated Caco‐2 cells
Authors: Stan S , Levy E , Bendayan M , Zoltowska M , Lambert M , Michaud J , Asselin C , Delvin E.E
Published: July 2002

It has been established that leptin displays a number of effects on peripheral tissues. We have investigated the effect of the hormone on lipid synthesis, apolipoprotein biogenesis and lipoprotein secretion in Caco‐2 cells. Immunocytochemistry revealed the presence of leptin receptors (Ob‐Rb) on the basolateral membrane. Incubation of cells with 200 nM leptin resulted in a decreased export of triglycerides in the basolateral medium without affecting monoglyceride, diglyceride and cholesterol ester lipid classes. It also significantly reduced the output of de novo‐synthesized apolipoprotein (Apo)B‐100 and ApoB‐48 as well as that of newly formed chylomicrons and of low‐density lipoproteins. It also enhanced that of ApoA‐I, ApoA‐IV and ApoE. Our results support the hypothesis that leptin can affect energy balance at the gut level by reducing lipid release into the circulation.
Analysis of connexin43 gene expression induced by retinoic acid in F9 teratocarcinoma cells
Authors: Clairmont Annette , Tessmann Dirk , Sies Helmut
Published: July 2002

All‐trans retinoic acid (10−7 M) induces cell‐cell communication and expression of the gap junction protein connexin43 in mouse F9 teratocarcinoma cells. Northern blot analysis revealed an increase of connexin43 mRNA after treatment with retinoic acid, accompanied by an increase of the mRNA of collagen IV, a differentiation marker. To address the question at what level gene expression is enhanced by retinoic acid, nuclear run‐on experiments were carried out. There was no detectable change in the level of newly transcribed connexin43 mRNA. Therefore, we postulate a post‐transcriptional mechanism responsible for the regulation of connexin43 mRNA levels by retinoic acid.
Evidence for a Na+−Ca2+ exchanger in rat pancreatic ducts
Authors: Hug M. , Pahla C. , Novak I.
Published: July 2002

Only recently has it been recognized that intracellular Ca2+ is an important cellular mediator in pancreatic ducts. The aim of the present study was to characterize the Call efflux pathway in ducts freshly prepared from rat pancreas. Lowering of extracellular Na+ concentration resulted in a significant increase in intracellular Ca2+. This effect was fast, reversible, dependent on the extracellular Na+ concentration and did not correlate with intracellular pH changes. It was abolished in Ca2+‐free solutions, indicating that the outwardly directed Na+ gradient was directly coupled to a flufenamate insensitive Ca2+ influx. Removal and reintroduction of extracellular Na+ induced transient hyperpolarization and depolarization of V
m, respectively. Taken together, our data indicate that pancreatic ducts possess an electrogenic Na+−Ca2+ exchanger, which under control conditions is responsible for transporting Ca2+ out of resting duct cells.
The packaging capacity of adeno‐associated virus (AAV) and the potential for wild‐type‐plus AAV gene therapy vectors
Authors: Hermonat Paul L. , Quirk J.Gerald , Bishop Brian M. , Han Li
Published: July 2002

Because of its ability to integrate chromosomally and its non‐pathogenic nature, adeno‐associated virus (AAV) has significant potential as a human gene therapy vector. Here we investigate the maximum amount of DNA which can be inserted into the AAV genome and still allow efficient packaging into an infectious virus particle. Altered wild‐type AAV genomes were constructed with inserts, which increased in size by 100 bp, ligated at map unit 96. These large wild‐type‐plus genomes were able to replicate and produce infectious virus, at levels slightly reduced but comparable to normal sized wild type, until the insert size reached 1 kb. These data indicate that the maximum effective packaging capacity of AAV is approximately 900 bp larger than wild type, or 119%. Furthermore, it is demonstrated that these large AAV genomes are able to latently infect cells by chromosomal integration as does wild‐type AAV. These data suggest that therapy vectors carrying a foreign gene of 900 bp or less can be generated from AAV, by ligation into non‐essential locations, and result in a recombinant AAV virus with a fully wild‐type phenotype. Such wild‐type‐plus AAV vectors will have both advantages and disadvantages over defective recombinant AAV virus — the most important advantages being the ease in which high titers of infectious virus can be generated and the ability to specifically integrate within chromosome 19. Once the concern subsides over the presence of wild‐type AAV in clinical applications, wild‐type AAV vectors may find specific application niches for use in human gene therapy.
Human recombinant tissue‐factor pathway inhibitor prevents the proliferation of cultured human neonatal aortic smooth muscle cells
Authors: Kamikubo Yu-ichi , Nakahara Yo , Takemoto Sumiyo , Hamuro Tsutomu , Miyamoto Seiji , Funatsu Akinobu
Published: July 2002

Tissue‐factor pathway inhibitor (TFPI) inhibits the procoagulant activity of the tissue‐factor/factor VIIa complex. It was recently reported that TFPI prevented restenosis following tissue injury in a rabbit atherosclerotic model. In order to clarify the mechanism behind this successful prevention of restenosis, we investigated the direct effect of human recombinant TFPI (h‐rTFPI) on the proliferation of cultured human neonatal aortic smooth muscle cells (hSMC). We found that h‐rTFPI exhibits inhibitory activity toward hSMC proliferation, while h‐rTFPI‐C which lacks the carboxyl (C)‐terminal region does not. Furthermore, we found that h‐rTFPI binds to hSMCs with K
d=526 nM but that this binding is inhibited by the addition of the synthetic C‐terminal peptide, Lys254–Met276, to h‐rTFPI. Thus, the interaction of h‐rTFPI with hSMCs mediated via the C‐terminal region is responsible for the anti‐proliferative action of h‐rTFPI. On the basis of these results, we presume that the anti‐proliferative effect of h‐rTFPI in addition to its anticoagulant function plays a significant role in preventing restenosis following tissue injury.
Behaviour of nitric oxide synthase in rat cerebellar granule cells differentiating in culture
Authors: Viani Paola , Giussani Paola , Riboni Laura , Bassi Rosaria , Tettamanti Guido
Published: July 2002

The possible relation between nitric oxide synthase (NOS) activity and neural differentiation was investigated using primary cultures of rat cerebellar granule cells differentiating in culture. NOS activity was measured in the cytosolic and particulate fractions obtained from cell homogenate. In the experimental conditions used the optimal pH for NOS activity was about 6.4, the activity being about 3‐fold higher than at pH 7.4. Cerebellar granule cell differentiation was associated with marked increases in NOS activity. In undifferentiated cells the enzyme was almost evenly distributed between the cytosolic and particulate fractions, during differentiation there was a 12‐fold increase in activity in the cytosolic enzyme and a 3‐fold increase in the particulate one. This indicates a marked preferential enrichment of the cytosolic enzyme during differentiation. Cerebellar granule cells produced and released NO in the culture medium; NO formation being markedly higher in differentiated cells (7–12 DIC) than in undifferentiated (2–3 DIC) ones. These data demonstrate a relationship between NOS expression and NO production and the differentiation of cerebellar granule cells, supporting the notion that NO may play a role in this process.
Expressional downregulation of neuronal‐type NO synthase I in guinea pig skeletal muscle in response to bacterial lipopolysaccharide
Authors: Gath Ingolf , Gödtel-Armbrust Ute , Förstermann Ulrich
Published: July 2002

We have investigated the expression of neuronal‐type NO synthase I (NOS I) and inducible‐type NOS II in guinea pig skeletal muscle (diaphragm). Expression of NOS I mRNA and protein was highest in muscle of specific pathogen‐free animals, lower in normally bred animals, and lowest in lipopolysaccharide (LPS)‐treated animals. NOS II mRNA and protein levels were highest in muscle of LPS‐treated animals. Elevated NOS activity in muscle from LPS‐treated animals was less susceptible to the NOS I‐selective inhibitor NG‐nitro‐l‐arginine. Expressional downregulation of NOS I in sepsis may have implications for contractile function of skeletal muscle.
Role of the prohormone convertase PC2 in the processing of proglucagon to glucagon
Authors: Rouillé Yves , Bianchi Matteo , Irminger Jean-Claude , Halban Philippe A.
Published: July 2002

Proglucagon is alternatively processed to glucagon in pancreatic α‐cells, or to glucagon‐like peptide‐1 in intestinal L cells. Here, the specificity of PC2, the major prohormone convertase of α‐cells, was examined both in vivo and in vitro. Adenovirus‐mediated co‐expression of proglucagon and PC2 in GH4C1 cells resulted in a pattern of processing products very similar to that observed in α‐cells. Oxyntomodulin, an intermediate in the processing of proglucagon, was quantitatively converted to glucagon in vitro by purified recombinant PC2, in combination with carboxypeptidase E. It is concluded that PC2 is able to act alone in the pancreatic pathway of proglucagon processing.
Requirement of intact human ceruloplasmin for the glutathione‐linked peroxidase activity
Authors: Kim In Gyu , Park Seon Young
Published: July 2002

Structural integrity may be needed for the glutathione‐linked peroxidase activity of human ceruloplasmin. Intact human ceruloplasmin has a potent peroxidase property to decompose H2O2 in the presence of reduced glutathione. However, the fragment of approximately 116 000 Da produced by proteolytic degradation had less than one‐third of the glutathione‐linked peroxidase activity of intact ceruloplasmin. When further proteolysis occurred, glutathione‐linked peroxidase activity of human ceruloplasmin disappeared. In contrast, ceruloplasmin (116 000 Da and <96 000 Da) fragmented by proteolysis significantly removed H2O2 irrespective of the presence of reduced glutathione. Although proteolytic fragmentation of ceruloplasmin occurs, the antioxidant activity of ceruloplasmin that prevents DNA strand breaks in a metal‐catalyzed reaction system was significantly maintained.
Selective involvement of caspase‐3 in ceramide induced apoptosis in AK‐5 tumor cells
Authors: Anjum Rana , Ali A.Mubarak , Begum Zareena , Vanaja J. , Khar Ashok
Published: July 2002

Ceramide, a product of sphingomyelin metabolism, is a novel lipid second messenger that mediates diverse cellular functions. The present study demonstrates the activation of caspase‐3/CPP‐32β, during apoptosis induced by cell permeable exogenous ceramides, in AK‐5 tumor, a spontaneously regressing rat histiocytoma. The apoptotic events were suppressed by the caspase‐3 specific tetrapeptide inhibitor DEVD‐CHO but not by the caspase‐1 inhibitor YVAD‐CMK. In cells overexpressing Bcl‐2, a significant decrease in cell death was observed after exogenous addition of ceramides. Furthermore the processing of caspase‐3 to its active form upon apoptotic stimulus, and the subsequent cleavage of the substrate PARP, suggested a central role for caspase‐3 in the ceramide mediated apoptosis in AK‐5 tumor cells.
Overexpression of the multidrug resistance‐associated protein (MRP1) in human heavy metal‐selected tumor cells
Authors: Vernhet Laurent , Courtois Arnaud , Allain Nathalie , Payen Léa , Anger Jean-Pierre , Guillouzo André , Fardel Olivier
Published: July 2002

Cellular and molecular mechanisms involved in the resistance to cytotoxic heavy metals remain largely to be characterized in mammalian cells. To this end, we have analyzed a metal‐resistant variant of the human lung cancer GLC4 cell line that we have selected by a step‐wise procedure in potassium antimony tartrate. Antimony‐selected cells, termed GLC4/Sb30 cells, poorly accumulated antimony through an enhanced cellular efflux of metal, thus suggesting up‐regulation of a membrane export system in these cells. Indeed, GLC4/Sb30 cells were found to display a functional overexpression of the multidrug resistance‐associated protein MRP1, a drug export pump, as demonstrated by Western blotting, reverse transcriptase‐polymerase chain reaction and calcein accumulation assays. Moreover, MK571, a potent inhibitor of MRP1 activity, was found to markedly down‐modulate resistance of GLC4/Sb30 cells to antimony and to decrease cellular export of the metal. Taken together, our data support the conclusion that overexpression of functional MRP1 likely represents one major mechanism by which human cells can escape the cytotoxic effects of heavy metals.
H+‐proton‐pumping inorganic pyrophosphatase: a tightly membrane‐bound family
Authors: Baltscheffsky Margareta , Schultz Anders , Baltscheffsky Herrick
Published: July 2002

The earliest known H+‐proton‐pumping inorganic pyrophosphatase, the integrally membrane‐bound H+‐proton‐pumping inorganic pyrophosphate synthase from Rhodospirillum rubrum, is still the only alternative to H+‐ATP synthase in biological electron transport phosphorylation. Cloning of several higher plant vacuolar H+‐proton‐pumping inorganic pyrophosphatase genes has led to the recognition that the corresponding proteins form a family of extremely similar proton‐pumping enzymes. The bacterial H+‐proton‐pumping inorganic pyrophosphate synthase and two algal vacuolar H+‐proton‐pumping inorganic pyrophosphatases are homologous with this family, as deduced from their cloned genes. The prokaryotic and algal homologues differ more than the H+‐proton‐pumping inorganic pyrophosphatases from higher plants, facilitating recognition of functionally significant entities. Primary structures of H+‐proton‐pumping inorganic pyrophosphatases are reviewed and compared with H+‐ATPases and soluble proton‐pumping inorganic pyrophosphatases.
Differential expression of gap‐junction gene connexin 31 in seminiferous epithelium of rat testes
Authors: Mok Bobo W , Yeung William S.B , Luk John M
Published: July 2002

Spermatogenesis, a tightly regulated developmental process of male germ cells in testis, is associated with temporal and spatial expression of certain gap‐junction connexins. Our findings by RT‐PCR indicate that the Cx31 gene is expressed in testis tissue of adult and postnatal rats. During the postnatal spermatogenic process, the Cx31‐specific signal became detectable at 15 dpp and onward by in situ hybridization, and apparently localized in the basal compartment of seminiferous epithelium where active spermatogonia and early primary spermatocytes reside. No signal was found in the luminal region. In adult testes, spermatids of elongation phase were also Cx31 positive. Immunohistochemical analysis with mouse anti‐Cx31 antibody gave a similar staining pattern, providing further evidence that the gap‐junction protein is abundant in the basal seminiferous epithelium, in accordance with the cellular distribution of Cx31 mRNA. These results represent the first demonstration of Cx31 expression at both transcriptional and protein levels in the seminiferous epithelium of rat testes. Thus, Cx31 may play a role in cell‐cell communication during spermatogenesis.
The two analogous phosphoglycerate mutases of Escherichia coli
Authors: Fraser Heather I , Kvaratskhelia Mamuka , White Malcolm F
Published: July 2002

The glycolytic enzyme phosphoglycerate mutase exists in two evolutionarily unrelated forms. Vertebrates have only the 2,3‐bisphosphoglycerate‐dependent enzyme (dPGM), whilst higher plants have only the cofactor‐independent enzyme (iPGM). Certain eubacteria possess genes encoding both enzymes, and their respective metabolic roles and activities are unclear. We have over‐expressed, purified and characterised the two PGMs of Escherichia coli. Both are expressed at high levels, but dPGM has a 10‐fold higher specific activity than iPGM. Differential inhibition by vanadate was observed. The presence of an integral manganese ion in iPGM was confirmed by EPR spectroscopy.