bluuebunny/crossref_metadata_2025 huggingface dataset:
Graded titin cleavage progressively reduces tension and uncovers the source of A-band stability in contracting muscle
Authors: Li Yong , Hessel Anthony L , Unger Andreas , Ing David , Recker Jannik , Koser Franziska , Freundt Johanna K , Linke Wolfgang A
Published: December 2020

The giant muscle protein titin is a major contributor to passive force; however, its role in active force generation is unresolved. Here, we use a novel titin-cleavage (TC) mouse model that allows specific and rapid cutting of elastic titin to quantify how titin-based forces define myocyte ultrastructure and mechanics. We show that under mechanical strain, as TC doubles from heterozygous to homozygous TC muscles, Z-disks become increasingly out of register while passive and active forces are reduced. Interactions of elastic titin with sarcomeric actin filaments are revealed. Strikingly, when titin-cleaved muscles contract, myosin-containing A-bands become split and adjacent myosin filaments move in opposite directions while also shedding myosins. This establishes intact titin filaments as critical force-transmission networks, buffering the forces observed by myosin filaments during contraction. To perform this function, elastic titin must change stiffness or extensible length, unveiling its fundamental role as an activation-dependent spring in contracting muscle.
Ledelse og styring i helsesektoren – en balansekunst mellom tillit og kontroll
Authors: Kjekshus Lars Erik
Published: December 2020

Tillit blir sett på som gullet i nordisk arbeidsliv. Samtidig hevdes det at nye styringsreformer som mål- og resultatstyring har skapt en tillitskrise i forholdet mellom arbeidsgiver og arbeidstakere i offentlig sektor og at det er behov for en tillitsreform. Det er imidlertid uklart hva slike reformer skal inneholde og hvordan de vil virke i praksis. I denne artikkelen presenterer en analytisk modell som kan bidra til å forstå betydningen av ulike styring- og ledelsesideal, situasjonsdefinisjon, kontekst og grad av målenighet som viktige faktorer for tillit i arbeidslivet. Det empiriske grunnlaget for artikkelen er offentlige dokumenter og publiserte studier av styringsreformene i sykehussektoren. Empirien blir i denne sammenhengen brukt for å eksemplifisere og utdype en analytisk modell for forståelse av tillit i arbeidslivet og framsette hypoteser som vil kunne testes empirisk. Det teoretiske utgangspunktet er forståelsen av offentlige organisasjoner som komplekse virksomheter med inkonsistente mål og sammensatte ledelsesideal. I denne sammenhengen skiller jeg mellom fagledelse og profesjonell ledelse. I realiteten vil ikke ledelsesidealene finnes i en rendyrket form. Sektorer med sterke profesjonsnormer og autonomi er særlig sårbare for at styring og kontroll fører til mistillit, og slike sektorer har derfor behov for mer balanserte ledelsesidealer.
A Study on the Knowledge Level and Extent of Adoption of Plant Protection Measures against Blast Disease of Rice by the Farmers of Indian Sundarbans
Authors: Nath Sabita , Mondal Bholanath , Mondal Palash
Published: December 2020

The study was conducted to know the knowledge and adoption level of plant protection measures against blast disease among 80 respondent paddy growers in the blocks of North and South 24 Parganas of Sundarbans. About 48.75% of the respondents had medium knowledge. Majority of the respondents (75%) knew about blast disease of rice and its key identifying symptom. The 67.5% farmers were having the knowledge about the fungicides used against the disease (Tricyclazole 75 WP, Carbendazim 50 WP, Hexaconazole 5EC), and 22.5% of the farmers knowing about the recommended dose of fungicide application.  The 28.75% of the respondents also knew that the fungicide should be applied at the first appearance of the disease. Further, it has been found that the adoption level of plant protection measures against blast disease of rice was medium (47.5%). Nearly 53.75% of the respondents practicing rice cultivation were in the middle age group of 31-50 years.  Most of the respondent had either 0.13-0.27ha (22.5%) or 0.40-0.67ha (37.5%) landholding wherein they were practicing rice cultivation. Almost all the respondents (100%) possessed Knapsack or hand sprayer for fungicide application. Climatic vagaries, lack of knowledge about to the number of sprays and concerning technology application, non-availability of fungicide on time, lack of facility at the nearby place were the major constraints as expressed by 95, 83.75, 85, 90, and 95 per cent of respondents, respectively. The high cost of chemicals and expensiveness and non-availability of labour during peak cropping period were also the major constraints as expressed by 60 and 83.75 per cent of the respondents, respectively. There was a significant relationship between age, education, landholding, social, mass media and participation in extension activities with knowledge and adoption levels of the farmers of the Indian Sundarbans.
Docility Behavioral Development in Nilgai (Boselaphus tragocamelus), a Signs of Taming towards Domestication
Authors: Prasad Suday , Prabhakar C. S.
Published: December 2020

Nilgai has some unique ecological function and they may be beneficial in many ways. Killing of Nilgai is not a long - term solution to overcome human- animal conflict. A study was conducted to know the docility pattern and behavior of Nilgai (Boselaphus tragocamelus) in Bihar state, India. Present docility pattern shows that adult females graze with juveniles and dwelling near the human habitation in proximity of in a close distance in anthropogenic environments. It also grazes and share food & fodders with domestic animals like cow, goat, and buffalo in periphery of village areas. Only males possess horns though a few females may be horned as well. Females were less aggressive than males and are of different size and color. Adult males are in blue grey color which reveals sign of territoriality, whereas females color is light in shade which showed evidence of the existence of social hierarchy and increased docility behavior. Females were sitting in group with juveniles in gregarious forms, however, male were found to be scattered. Nilgai migrates in search of food towards cultivated grass, agricultural crops and periphery of the villages areas during dusk and return when less human activity during dawn. Shahabad area Bhojpur, Buxar & Sasaram are characterized by extreme hot and heavy rains. During the unfavorable condition (Rainy and summer season) they: showed seasonal migratory behavior. These behaviors marked in Nilgai may be developing closer social bonds with human being on a way towards domestic relationship. It can be integrated into human society in fevour of co-existence as well as a step towards domestication useful for human in coming future.
Traditional, Medicinal and Nutraceutical Values of Minor Fruit: Longan
Authors: Lal Narayan , Sahu Nisha , Jayswal D. K. , Diwan Garima , Tandon Khushboo
Published: December 2020

This review will help to exploit the potential uses of longan, an exotic sub- tropical fruit which has high therapeutic values. In this review, traditional value, nutritional composition, bioactive compounds and other uses have been focused. Longan fruits are very tasty and its organoleptic qualities are unique because fruit has a succulent, edible and white aril, which has gained popularity. Longan fruits have immense potential in food and pharmaceutical industries. Longan aril, peel and seed extract have anti-glycated, anti-tyrosinase and anticancer properties, and memory enhancing effects which contribute to healthy human health. In China, the entire area of litchi is shifting to longan, which indicates the importance of longan crop and free from production barriers (poor fruit set, fruit drop, sun burn, fruit cracking, insect and pests) in longan cultivation make it popular among the peoples in India. This review will highlight the uses of longan for different purposes.
Isolation and Identification of Fungi Associated With Rot of Watermelon Fruit in Sokoto Metropolitan, Sokoto State, Nigeria
Authors: Alhaji Y. I. , Lema S. Y. , Ibrahim J. , Umar A. , Garba M.
Published: December 2020

Watermelon fruit contain high vitamins and minerals. Watermelon is susceptible to many pathogenic microorganisms that results to unpleasant odours and cause foodborne diseases. This study was conducted to isolate and identify fungi that are associated with rot of watermelon fruit in Sokoto metropolitan. The presence of fungal organisms was examined in five different locations within Sokoto metropolitan. Isolated fungus was identified morphologically, microscopically and using molecular standard procedures. Results showed that (3- Aspergillus is one gemus) 4 fungal genera were isolated and Identified. The isolated fungi were Asperqillus flavus, Aspergillus niger. Rhizopus stolonifer and Mucor spp. Fungi isolated from this study are of economical and public health importance. This study was carried out to examine the fungi associated with the rot of watermelon fruit in Sokoto metropolitan. Careful handling of watermelon  fruit are recommended to ensure longer shelf-life, prevent spread of rot pathogens and keep fruit in the highest quality before consumption.
A Report of Unprovoked Bilateral Epistaxis in Patient with Covid-19: Our Experience
Authors: Ehimen Ferguson Ayemere , Akpan Iboro Samuel , Abidoye Oluwafemi Emmanuel , Betiku Omobamidele Benson , Olanrewaju Kayode
Published: December 2020

Coronavirus disease 2019 (COVID-19) is a viral disease that was first reported in China in 2019. Since it was reported, it has resulted to close to nine hundred thousand deaths globally. The symptoms and signs of COVID-19 continue to evolve on a daily basis, therefore a knowledge of the common symptoms and other new symptoms is key to early diagnosis and control of this disease. In this report, we present a 30 year-old COVID-19 female patient, who presented with acute unprovoked epistaxis, a week after onset of symptoms (cough, malaise, fatigue) of COVID-19. Considering the evolving symptoms of COVID-19, health care personnel are advised to consider the possibility of COVID-19 in patients presenting with atypical symptoms like sudden unprovoked epistaxis especially during the pandemic period.

This report further strengthens the need for more large inter-country studies to be done to completely highlight and harmonize the varying and evolving symptoms of COVID-19.
Observations on programs to estimate the parameters of enzyme kinetics
Authors: Gardiner W.R. , Ottaway J.H.
Published: July 2002

This paper gives a critical account of the two major programs so far published specifically to estimate the parameters of enzyme kinetics. The dangers of submitting data to the programs without proper checks are discussed, and a screening test is described to identifty sets of data which may not be best fitted by a rectangular hyperbola.
The maximum capacity of glycolysis in brown adipose tissue and its relationship to control of the blood glucose concentration
Authors: Cooney Gregory J. , Newsholme Eric A.
Published: July 2002

The maximum activity of the key glycolytic enzymes, hexokinase and 6‐phosphofrustokinase, was measured in tissues of control and cold‐acclimated rats. The only significant change in activity was seen in brown adipose tissue where the activity of these enzymes was increased 2‐fold. This increase in glycolytic capacity along with the hypertrophy of BAT observed in cold acclimation suggests that this tissue could play an important role in glucose utilisation by the rat.
Some properties of a blue copper protein ‘plantacyanin’ from cucumber peel
Authors: Sakurai Takeshi , Okamoto Hideyuki , Kawahara Keizo , Nakahara Akitsugu
Published: July 2002

Absorption, circular dichroism, electron spin resonance and resonance Raman spectra of a blue copper protein, plantacyanin from cucumber peel have been measured and these spectral properties compared with those of other blue copper proteins. From the spectral properties, amino acid analysis and redox potential, we discuss the active site and redox properties of this protein.
Synthesis and biological activity of a fluorescent analogue of 2—5A
Authors: Lesiak Krystyna , Torrence Paul F.
Published: July 2002

A fluorescent analogue of 2—5A, ppp5′ ϵA2′p5′ϵA2′p5′ϵA, was obtained by reaction of 2′, 5′ (pA)3 with chloroacetaldehyde followed by conversion to the 5‐triphosphate through reaction of the corresponding phosphoroimidazolide with pyrophosphate anion. The 5′‐monophosphate, p5′ϵA2′p5′ϵA2′p5′ϵA, was not an antagonist of 2—5A action in extracts of mouse L cells. Neither did the 5′‐triphosphate, ppp5′ϵA2′p5′ϵA2′p5′ϵA, inhibit translation. Moreover, the 5′‐triphosphate was bound to the 2—5A‐dependent endonuclease 5000‐times less effectively than 2—5A itself.
Phospholipid‐sensitive Ca2+‐dependent protein kinase phosphorylates the β subunit of eukaryotic initiation factor 2 (eIF‐2)
Authors: Schatzman Randall C. , Grifo Jamie A. , Merrick William C. , Kuo J.F.
Published: July 2002

The ability of homogeneous phospholipid‐sensitive Ca2+‐dependent protein kinase (PL‐Ca‐PK) from pig spleen to phosphorylate eukaryotic initiation factor 2 (eIF‐2) was examined. PL‐Ca‐PK phosphorylated the β‐subunit of eIF‐2, whereas myosin light chain kinase (MLCK) and cyclic AMP‐ and cyclic GMP‐dependent protein kinases (cA‐PK and cG‐PK) did not. PL‐Ca‐PK could incorporate a maximum of 1.6 mol phosphate/mol eIF‐2. The app. K
m and V
max for PL‐Ca‐PK phosphorylation of eIF‐2 were 0.13 μM and 0.02 μmol. min−1.mg enzyme−1, respectively. Phosphoamino acid analysis revealed that incorporation of phosphate into eIF‐2 occurred almost exclusively at serine residues. These findings indicate that eIF‐2 was an effective substrate for PL‐Ca‐PK, suggesting that this enzyme may play a role in the regulation of protein synthesis.
Part of the 23S RNA located in the 11S RNA fragment is a constituent of the ribosomal peptidyltransferase centre
Authors: Barta Andrea , Kuechler Ernst
Published: July 2002

Upon irradiation, 3‐[4‐benzoylphenyl]propionyl‐PhetRNA bound to the P‐site of poly(U)‐primed ribosomes is exclusively cross‐linked to 23S RNA. It is shown that the photoreaction only occurs with pyrimidine nucleotides. The site of the cross‐link is located within an 11S RNA fragment, which comprises the 1100 nucleotides at the 3′‐end of 23S RNA. The cross‐linked Phe tRNA derivative is still functionally active in peptide bond formation. The site labelled on the 11S fragment is therefore an integral part of the peptidyltransferase centre.
Noradrenaline controls the concentration of the uncoupling protein in brown adipose tissue
Authors: Mory G. , Bouillaud F. , Combes-George M. , Ricquier D.
Published: July 2002

The importance of noradrenaline in the control of the level of the uncoupling protein responsible for the high thermogenic capacity of brown adipose tissue mitochondria was examined. It was observed that chronic infusion of noradrenaline through mini‐osmotic pumps increased the mitochondrial concentration of this uncoupling protein to the same extent as chronic exposure to cold.
Proton magnetic resonance studies of 7Fe ferredoxins
Authors: Nagayama K. , Imax T. , Ohmori D. , Oshima T.
Published: July 2002

The redox couples in 7Fe ferredoxins (Fd) treated with ferricyanide were monitored by 1H‐NMR. An excess amount of ferricyanide was found to effect conversion of one of the two redox centers, the 4Fe core, to a 3Fe core in the ferredoxins extracted from Thermus thermophilus, Mycobacterium smegmatis and Pseudomonas ovalis. On long term incubation in air, the converted 3Fe core showed even further change in NMR spectra.
DNA polyintercalation: comparison of DNA binding properties of an acridine dimer and trimer
Authors: Gaugain Bernard , Markovits Judith , Le Pecq Jean-Bernard , Roques Bernard P.
Published: July 2002

The DNA binding characteristics of a mono‐, di‐ and trimeric derivative of 9‐aminoacridine were studied. The length of the linking carboxyamidoalkyl chains was selected to allow bis‐ or tris‐intercalation according to the excluded‐site model. Measurements of DNA unwinding angle using closed circular DNA showed that the trimeric derivative behaves as a tris‐intercalating agent. Nevertheless the increase of DNA binding affinity on going from dimer to trimer was found to be relatively small. This is probably related to the large structural constraint for DNA binding of the trimeric derivative. The nature of the linking chain for the design of high‐affinity DNA poly‐intercalating agents appears therefore critical.
The effect of insulin on Fru‐2,6‐P2 levels in human fibroblasts
Authors: Farnararo Marta , Vasta Valeria , Bruni Paola , D'Alessandro Antonino
Published: July 2002

We report that fructose 2,6‐bisphosphate (Fru‐2,6‐P2) levels in quiescent human fibroblasts stimulated with insulin treatment increase in a time‐ and dose‐dependent manner. The biochemical role of the sugar phosphate in the cellular response to the hormone which controls carbohydrate metabolism and acts as mitogenic factor is discussed.
The amino acid sequences of the α 1 and α 2 subunits of the isoelectins from seeds of Lathyrus ochrus (L) DC
Authors: Richardson M. , Rougé P. , Sousa-Cavada B. , Yarwood A.
Published: July 2002

Lathyrus ochrus isoelectin
α Subunit
Amino acid sequence
Homology
Legume lectin
A new procedure for the isolation of the brain myelin basic protein in a lipid‐bound form
Authors: Riccio P. , Rosenbusch J.P. , Quagliariello E.
Published: July 2002

Myelin
Basic protein
Protein purification
Lipid
Protein structure
Multiple sclerosis
Occurrence and location of 7‐methylguanine residues in small‐subunit ribosomal RNAs from eubacteria, archaebacteria and eukaryotes
Authors: Zueva Vera S. , Mankin Alexander S. , Bogdanov Alexei A. , Thurlow David L. , Zimmermann Robert A
Published: July 2002

Specific cleavage with aniline provides a rapid and convenient method for establishing the presence and approximate location of 7‐methyl‐guanine (m7G) residues in ribosomal RNA (rRNA) molecules. Using this approach, we have shown that a single m7G occurs roughly 465 bases from the 5'‐end of 16 S rRNA from the archaebacterium. Thermoplasma acidophilum, but that this modified base is absent from several other archaebacterial 16 S rRNAs. We have also demonstrated that a unique m7G is found some 220–230 bases from the 3'‐terminus of a number of eukaryotic 18 S rRNAs. In both cases, m7G is present within evolutionarily conserved structural features, suggesting that this base may optimize the activity of functionally important regions of rRNAs in a kingdom‐specific fashion.
Congenital jaundice in rats due to the absence of hepatic bilirubin UDP‐glucuronyltransferase enzyme protein
Authors: Scragg Isobel , Celier Chantal , Burchell Brian
Published: July 2002

Gunn rat
Purified isoenzyme
Immunoblot analysis
Clofibrate
Fetal rat
Antagonism of 2–5 A‐mediated inhibition of protein synthesis in intact cells by 2',5'‐(pA)3
Authors: Black Roberta J. , Friedman R.M. , Imai Jiro , Torrence Paul F.
Published: July 2002

In vitro studies have shown that the translational inhibitory activity of 2–5 A can be blocked by the oligoribonucleotide 2',5'‐(pA)3. We have examined the effect of simultaneous introduction of inhibitor and antagonist into intact mouse cells using calcium phosphate coprecipitation. Upon introduction of 10−4 M 2',5'‐(pA)3 and 10−6 M 2–5 A, inhibition of protein synthesis was prevented. Efficiency of calcium phosphate precipitation of 2–5 A in the presence or absence of 2',5'‐(pA)3 was comparable. Introduction of 2',5'‐(pA)3 analogs showed that nucleotides which do not bind well to the 2–5 A dependent endonuclease do not prevent 2–5 A inhibitory activity. Thus, 2',5'‐(pA)3 functions as an antagonist of 2–5 A in vivo.
Asp 718 from a non‐pathogenic species of the genus Achromobacter: a KpnI isoschizomer generating DNA‐fragments with 5'‐protruding ends
Authors: Bolton Bryan J. , Nesch Georg , Comer Michael J. , Wolf Werner , Kessler Christoph
Published: July 2002

Restriction endonuclease KpnI isoschizomer
5'‐Protruding terminus
T4 polynucleotide kinase
Klenow enzyme
Amino acid substitutions in mitochondrial ATPase subunit 6 of Saccharomyces cerevisiae leading to oligomycin resistance
Authors: John Ulrik P. , Nagley Phillip
Published: July 2002

The amino acid substitutions in subunit 6 of the mitochondrial ATPase complex have been determined for 4 oligomycin resistant mutants of Saccharomyces cerevisiae. The data were obtained for each mutant by nucleotide sequence analysis of the mitochondrial oli2 gene. Amino acid substitutions conferring oligomycin resistance in subunit 6 are located in two conserved regions that are thought to form domains which span the inner mitochondrial membrane. The disposition of these amino acid substitutions is consistent with the view that these two membrane‐spanning domains interact structurally and functionally with the DCCD‐binding proteolipid subunit 9 in the F0‐sector.
Physical nature of the phase transition in globular proteins
Authors: Pfeil Wolfgang , Bychkova Valentina E. , Ptitsyn Oleg B.
Published: July 2002

The guanidine hydrochloride‐induced unfolding of human α‐lactalbumin has been studied by isothermal calorimetry. It has been shown that a cooperative transition takes place only in the concentration interval of the denaturant between 0.3 and 2 mol · 1−1. The cooperative transition coincides with the transition detected by circular dichroism in the near‐ultraviolet region which reflects the destruction of the specific environment of aromatic side groups. According to scanning calorimetric investigations, the transition disappears in the acid form of the protein where circular dichroism of aromatic side groups is practically absent. At higher concentrations of guanidine hydrochloride, where destruction of the secondary structure and un‐ folding of the chain are observed, there is no cooperative heat absorption.
Lipid peroxidation in regenerating rat liver
Authors: Cheeseman K.H. , Collins M. , Maddix S. , Milia A. , Proudfoot K. , Slater T.F. , Burton G.W. , Webb A. , Ingold K.U.
Published: July 2002

Rats entrained to a strictly regulated lighting and feeding schedule have been subjected to partial hepatectomy or a sham operation. In the partially hepatectomised animals the period of liver regeneration is characterised by regular bursts of thymidine kinase activity. Liver microsomes from rats, at times corresponding to maximum thymidine kinase activity, have much reduced rates of lipid peroxidation compared to control preparations: this is due in part to increased levels of lipid‐soluble antioxidant at times of maximal DNA synthesis. This temporal relationship between thymidine kinase and lipid peroxidation is consistent with the view that lipid peroxidation is decreased prior to cell division.
The influence of the chain length of aldehydes on the fluorescence of chromolipids
Authors: Montfoort A. , Bezstarosti K. , Groh M.M.J. , Koster J.F.
Published: July 2002

Incubation of phosphatidylethanolamine containing liposomes with malondialdehyde and other aldehydes with different chain lengths results in the fluorescence of chromolipids. Relative to malondialdehyde, the fluorescence was greatly enhanced with increasing chain length upon incubation of 2‐alkenals with phospholipids. Similar results were found using the total lipid extracted from erythrocyte ghosts. It seems that the hydrophobic character of the aldehydes is important for the amount of fluorescence detected in lipid bilayers.
Histidine‐rich glycoprotein is evolutionarily related to the cystatin superfamily
Authors: Koide Takehiko , Odani Shoji
Published: July 2002

A new member of the cystatin superfamily is introduced. Human plasma histidine‐rich glycoprotein (HRG) was found to contain 2 cystatin‐like sequences in tandem in the N‐terminal region. Domain 1 (residues 1–112) was most homologous to domain 1 of the heavy chain of human kininogen and domain 2 (residues 113–225) was most homologous to human cystatin S as well as other cystatins and domain 3 of the heavy chain of kininogen, suggesting that the cystatin domains of HRG may represent a hitherto unknown binary form (or intermediate molecule) composed of 2 cystatin domains, and evolutionarily intermediate between the cystatin and the kininogen families.
N‐terminal methylation of proteins: Structure, function and specificity
Authors: Stock Ann , Clarke Steven , Clarke Catherine , Stock Jeff
Published: July 2002

A common site for the posttranslational modification of proteins is at the N‐terminal α‐amino group. Here we consider the enzymatic addition of one or more methyl groups that has been found to occur in several proteins. Although the methylated proteins have different overall functions, they all appear to be involved in large macromolecular structures such as ribosomes, myofibrils, nucleosomes, pilins, or flagella. Structural features at the N‐termini of these methylated proteins suggest that sequences in this region may serve as recognition sites for only a few different types of methylating enzymes. Thus, we propose that three enzymes could account for the N‐methylated species so far identified in bacteria, the hypothetical MAK, QP, and pilin methyltransferases, and a single additional enzyme, the hypothetical PK methyltransferase, could account for all of the α‐amino methylations observed in eukaryotic cells. Finally, we discuss criteria that could be used in conjuction with primary sequence data to predict proteins that might be subject to methylation at their amino termini.
Changes in the kinetic properties and phosphorylation state of phosphoenolpyruvate carboxylase in Zea mays leaves in reponse to light and dark
Authors: Nimmo Gillian A. , McNaughton Gavin A.L. , Fewson Charles A. , Wilkins Malcolm B. , Nimmo Hugh G.
Published: July 2002

In plants such as Zea mays that carry out C4 metabolism, phosphoenolpyruvate carboxylase catalyses the primary fixation of atmospheric CO2. The properties of this enzyme from Z. mays leaves kept in light and in darkness are different. In brightly illuminated leaves, which are actively fixing CO2, the enzyme is less sensitive to feedback inhibition by malate and is phosphorylated on one or more serine residues. In darkened leaves, which are not photosynthesising, the enzyme is more sensitive to inhibition by malate and is much less phosphorylated. This indicates that the activity of the enzyme is controlled by a reversible phosphorylation.
Inhibition of HIV replication by amino‐sugar derivatives
Authors: Fleet George W.J. , Karpas Abraham , Dwek Raymond A. , Fellows Linda E. , Tyms A.S. , Petursson Sigthor , Namgoong Sung K. , Ramsden Nigel G. , Smith Paul W. , Son Jong Chan , Wilson Francis , Witty David R. , Jacob Gary S. , Rademacher Thomas W.
Published: July 2002

The plant alkaloids castanospermine, dihydroxymethyldihydroxypyrrolidine and deoxynojirimycin have recently been shown to have potential anti‐HIV activity [(1987) Proc. Natl. Acad. Sci. USA 84, 8120–8124; (1987) Nature 330, 74–77; (1987) Lancet i, 1025–1026]. They are thought to act by inhibiting α‐glucosidase I, an enzyme involved in the processing of N‐linked oligosaccharides on glycoproteins. We report here the relative efficacy of a spectrum of amino‐sugar derivatives as inhibition of HIV cytopathicity. Several α‐glucosidase inhibitors and α‐fucosidase inhibitors were found to be active at concentrations which were non‐cytotoxic.
Effect of 7β‐hydroxycholesterol on growth and membrane composition of Mycoplasma capricolum
Authors: Lelong I. , Luu B. , Mersel M. , Rottem S.
Published: July 2002

7β‐OH cholesterol in a cholesterol rich growth medium (5–10 μg/ml) extended the lag period and slowed down the growth rate of Mycoplasma capricolum cells. In a cholesterol poor medium (0.5 μg/ml) inadequate to support growth, 7β‐OH cholesterol exerts a synergistic effect on growth. The 7β‐OH cholesterol was incorporated unchanged from the growth medium and could be recovered exclusively in the membrane fraction. The incorporation of the 7β‐OH cholesterol has no effect on the total phospholipid content but the DPG to PG ratio was markedly decreased. Exchange studies with lipid vesicles revealed that whereas most of the cholesterol underwent exchange, only about 20% of the 7β‐OH cholesterol was exchanged.
Evidence that during very low density lipoprotein assembly in rat hepatocytes most of the triacylglycerol and phospholipid are packaged with apolipoprotein B in the Golgi complex
Authors: Higgins Joan A.
Published: July 2002

Rat liver lipids were labelled by an intraportal injection of [3H]palmitic acid followed by isolation of rough and smooth endoplasmic reticulum or ‘cis’ or ‘trans’‐enriched Golgi fractions. The preparations were separated into membrane and contents and the apolipoprotein B of the content fractions was immunoprecipitated. More than 90% of the labelled triacylglycerol and phospholipid secreted into the blood immunoprecipitated with apolipoprotein B. Under the same experimental conditions 8, 12, 27 and 59% of the lipids of the rough, smooth, ‘cis‐Golgi’ and ‘trans‐Golgi’ contents, respectively, were immunoprecipitated. Thus, the ‘trans‐Golgi’ region appears to be the major intracellular site of assembly of apolipoprotein B with triacylglycerol and phospholipid.
Activation of interleukin‐ 1β by a co‐induced protease
Authors: Black Roy A. , Kronheim Shirley R. , Sleath Paul R.
Published: July 2002

The proteolytic generation of mature interleukin‐ 1β (IL‐1β) from its inactive precursor does not proceed by a conventional pathway for hormonal processing. Pro‐IL‐ 1β is found dispersed in the cytoplasm, and there are no basic amino acid residues or other commonly recognized processing sites adjoining the mature N‐terminus. Processing appears to occur during release of the hormone. In the present study, we have identified a specific protease that generates mature IL‐ 1β from the precursor. This enzyme is co‐induced with the hormone, and it differs in its cleavage specificity and inhibitor sensitivity from all known proteases.
Analysis of 3′‐untranslated regions of seven c‐myc genes reveals conserved elements prevalent in post‐transcriptionally regulated genes
Authors: Vriz Sophie , Méchali Marcel
Published: July 2002

We have characterized the complete sequence of two c‐myc cDNAs from the amphibian Xenopus laevis, and could thus compare the 3′‐non‐coding sequences of 7 myc cDNAs from 6 species spread over 350 million years of evolution. Although the size of these sequences is heterogeneous, we identified three completely conserved sequences of 10, 11 and 12 contiguous nucleotides. We observed that two of these elements may be contained in conserved stem‐loop structures previously implicated in mRNA turnover. The length of these motifs, their existence in conserved predicted structures, and their presence in regulated eukaryote mRNA with a frequency greater than predicted by chance, suggest that they are functionally important.
S‐phase inhibitors induce vimentin expression in human promonocytic U‐937 cells
Authors: Mata F. , Rius C. , Cabañas C. , Bernabeu C. , Aller P.
Published: July 2002

The administration of hydroxyurea (3 × 10−4M) and cytosine arabinoside (10−7 M) greatly induces the expression of the vimentin gene in human promonocytic leukemia U‐937 cells. The induction takes place at both the mRNA and protein levels, as demonstrated by Northern blot, immunoblot and immunofluorescence assays. On the contrary, the drugs inhibit the expression of c‐myc and omithine decarboxylase, and do not modify significantly the expression of β‐actin. Since hydroxyurea and cytosine arabinoside trigger the phenotypic differentiation of U‐937 cells, as demonstrated by the induction of the differentiation‐specific CDllb and CDllc antigens, it is concluded that vimentin expression might be implicated in the maturation of these cells.
Termination of the phytochelatin synthase reaction through sequestration of heavy metals by the reaction product
Authors: Loeffler Susanne , Hochberger Andreas , Grill Erwin , Winnacker Ernst-L. , Zenk Meinhart H.
Published: July 2002

The newly discovered enzyme γ‐glutamylcysteine dipeptidyl transpeptidase was purified to apparent homogeneity from cell suspension cultures of Silene cucubalus. The enzyme catalyzes, in the presence of heavy metal ions, the formation of metal chelating peptides, the phytochelatins, from glutathione. The stoichiometry of the transfer reaction for the first phytochelatin member was determined to be: 2 (γ‐Glu‐Cys)‐Gly → (γ‐Glu‐Cys)2‐Gly + Gly. The enzyme is self regulated in that the reaction products, the phytochelatins, chelate the enzyme activating metal, thus terminating the enzymatic reaction. The higher order phytochelatins have a higher relative complexing affinity than the lower ones, as judged from their ability to terminate the enzymatic reaction.
An ice nucleation active gene of Erwinia ananas
Authors: Abe Keiko , Watabe Satoshi , Emori Yasufumi , Watanabe Michiko , Arai Soichi
Published: July 2002

The ice nucleation active gene, inaA, of Erwinia ananas IN‐10 has been sequenced. This gene encodes a protein composed of 1322 amino acid residues. The inaA protein contains a 1120‐residue segment consisting of 70 repeats of closely related 16 amino acid motifs (R‐domain), which is flanked by N‐ and C‐terminal sequences (N‐ and C‐domains, respectively). Its primary structure is similar to, but not identical with, those of Pseudomonas inaW and inaZ gene products. By truncating the inaA gene to various extents, it was found that deletion of the C‐domain resulted in complete loss of the ice nucleation activity, whereas removal of the N‐domain led to a moderate decrease in the activity. Complete loss of the activity was also observed when the N‐domain plus a large part of the R‐domain were deleted. It is suggested that the C‐domain is required for the assembly of inaA protein to form a functional ice nucleus.
Characterization of high‐affinity receptors for truncated glucagon‐like peptide‐1 in rat gastric glands
Authors: Uttenthal L.O. , Blázquez E.
Published: July 2002

The truncated form of glucagon‐like peptide‐1 (TGLP‐1, or proglucagon 78–108), secreted by the mammalian intestine, has potent pharmacological activities, stimulating insulin release and inhibiting gastric acid secretion. We have characterized high‐affinity receptors for this peptide in rat isolated fundic glands. Scatchard analysis of binding studies using mono‐125I‐TGLP‐l(7–36) amide as tracer showed a single class of binding site of K
d (4.4±(SE) 0.8) × 10−10 M, with a tissue concentration of 1.0 ± 0.1 fmol sites/μg DNA. Whole GLP‐1 was approximately 700 times less potent in displacing tracer, while human GLP‐2 and pancreatic glucagon produced no significant displacement at concentrations up to 10−6 M. The data support a physiological role for TGLP‐1 in the regulation of gastric acid secretion.
Susceptibility of the cartilage collagens types II, IX and XI to degradation by the cysteine proteinases, cathepsins B and L
Authors: Maciewicz Rose A. , Wotton Sandra F. , Etherington David J. , Duance Victor C.
Published: July 2002

We have investigated the susceptibility of both the helical and non‐helical regions of isolated rat chondrosarcoma collagens, types II, IX and XI, to degradation by the cysteine proteinases, cathepsins B and L. Both enzymes degrade these collagens at temperatures from 20 to 37°C and pH values from 3.5 to 7.0. Cleavage occurs only within the non‐helical domains unless the helix is destabilized. Cathepsin L is more effective than cathepsin B on a molar basis and they appear to cleave at different sites. Since these cathepsins can degrade cartilage collagens at pH values near neutrality, they may contribute to the destruction of cartilage observed in arthritis.
An efficient NMR approach for obtaining sequence‐specific resonance assignments of larger proteins based on multiple isotopic labeling
Authors: Ikura Mitsuhiko , Krinks Marie , Torchia Dennis A. , Bax Ad
Published: July 2002

By simultaneously incorporating in a protein 13C‐carbonyl‐ and 15N‐labeled amino acids with different levels of enrichment, characteristic asymmetric doublet‐like patterns are observed for 15N nuclei that are directly adjacent to the 13C1‐labeled residues, providing unambiguous identification of a large number of unique dipeptide fragments of the protein. Additional assignments and qualitative structural information can be obtained from such a selectively labeled protein by recording multiple bond correlation spectra. The procedure is demonstrated for the protein calmodulin, complexed with calcium.
Studies on the role of the S4 substrate binding site of HIV proteinases
Authors: Tözsér József , Gustchina Alla , Weber Irene T. , Blaha Ivo , Wondrak Ewald M. , Oroszlan Stephen
Published: July 2002

Kinetic analysis of the hydrolysis of the peptide H‐Vat‐Ser‐Gin‐Asn‐Tyr*Pro‐He‐Val‐Gin‐NH2 and its analogs obtained by varying the length and introducing substitutions at the P4 site was carried out with both HIV‐1 and HIV‐2 proteinases. Deletion of the terminal Val and Gin had only moderate effect on the substrate hydrolysis, while the deletion of the P4, Ser as well as P3 Val greatly reduced the substrate hydrolysis. This is predicted to be due to the loss of interactions between main chains of the enzyme and the substrate. Substitution of the P4 Ser by amino acids having a high frequency of occurrence in β turns resulted in good substrates, while large amino acids were unfavourable in this position. The two proteinases acted similarly, except for substrates having Thr, Val and Leu substitutions, which were better accommodated in the HIV‐2 substrate binding pocket.
The signal peptide of human preproendothelin‐1
Authors: Fabbrini Maria Serena , Valsasina Barbara , Nitti Gianpaolo , Benatti Luca , Vitale Alessandro
Published: July 2002

Synthetic mRNAs were produced using either the complete coding sequence of a human preproendothelin‐1 cDNA clone or a truncated form in which the portion encoding the first 17 amino acids, representing a putative signal peptide for insertion into the endoplasmic reticulum, was replaced with a methionine codon. The mRNAs were translated in vitro in the presence or in the absence of microsomal membranes. Protection from trypsin digestion demonstrated that the full‐length polypeptide, but not the truncated form, could be inserted into the membranes. Sequence analysis revealed that membrane insertion is accompanied by removal of the first 17 amino acids. These results indicate that the first 17 amino acids of human preproendothelin‐1 are a functional signal peptide which allows the protein to enter the secretory pathway.
Antiviral activity of some natural and synthetic sugar analogues
Authors: Huang Richard , Dietsch Ellen , Lockhof Oswald , Schüller Matthias , Reutter Werner
Published: July 2002

A number of natural and synthetic sugar analogues have been tested for their antiviral activity, using an influenza virus strain as a model. Hemagglutinating titres (HA) and cytopathic effect (CPE) were surveyed to estimate the virus production. It was found that introduction of the benzyl group into these sugars generally causes them to become antivirally active. Substitution with methyl, acetyl, uridyl and thiocyanyl groups or derivatization with azido, isopropylidene and benzylidene groups were without effect. All sugars containing the 2‐deoxy‐2‐acetamido group were inactive.
Quantitation of a mitochondrial DNA deletion in Parkinson's disease
Authors: Mann Vincent M. , Cooper J.Mark , Schapira Anthony H.V.
Published: July 2002

A 5 kilobase deletion in mitochondrial DNA (mtDNA) has been reported to be responsible for the specific complex I deficiency in the substantia nigra (SN) of the Parkinson's disease (PD) brain. We have studied mitochondrial respiratory chain function in the SN from control and PD subjects, and analysed mtDNA, extracted from the same tissues, by Southern biot and the polymerase chain reaction (PCR). Quantitation of the levels of the deletion indicate that it does not contribute to the pathogenesis of PD nor to a complex I deficiency but seems likely to be an age‐related observation.
Purification and primary structure of murine cryptdin‐1, a Paneth cell defensin
Authors: Ouellette Andre J. , Miller Samuel I. , Henschen Agnes H. , Selsted Michael E.
Published: July 2002

We have purified and determined the amino acid sequence of cryptdin‐1, a murine Paneth cell defensin. The peptide corresponds to a previously characterized mRNA that accumulates to high abundance during postnatal ontogeny of the small bowel. Acid‐extracted intestinal protein was fractionated by cation‐exchange chromatography and fractions were assayed for antimicrobial activity. One peak of anti‐Salmonella activity contained a putative defensin, based on its predicted electrophoretic migration in acid‐urea PAGE. The peptide was purified to homogeneity by RP‐HPLC and sequenced. These studies demonstrate defensin expression in non‐myeloid tissue. The N‐terminal extension of cryptdin‐1 is a unique structural feature of this novel epithelial defensin.
Inhibitory effect of human chorionic gonadotropin (hCG) on HIV‐1 transmission from lymphocytes to trophoblasts
Authors: Bourinbaiar Aldar S. , Nagorny Raisa
Published: July 2002

It has been demonstrated that human chorionic gonadotropin (hCG) inhibits HIV production in vitro, suggesting that this soluble placental glycoprotein can control viral replication and spread in vivo, hCG ‐ the major product of fetal trophoblasts ‐ was tested on an in vitro model consisting of choriocarcinoma‐derived ENAMI trophoblasts exposed to HIV‐infected MOLT‐4 lymphocytes. The results show a U‐shaped antiviral dose‐ effect and suggest that hCG may contribute to protection against intrauterine transmission of HIV‐1.
Signal transduction in neutrophil activation Phosphatidylinositol 3‐kinase is stimulated without tyrosine phosphorylation
Authors: Vlahos Chris J. , Matter William F.
Published: July 2002

Treatment of human neutrophils with the peptide f‐Met‐Leu‐Phe (FMLP) results in neutrophil activation concomitant with stimulation of phosphatidylinositol (PtdIns) 3‐kinase activity as measured by production of PtdIns‐3,4,5‐P3 in [32P]orthophosphate labeled cells. Antiphosphotyrosine immunoprecipitates were assayed for PtdIns 3‐kinase activity; essentially no activity was present in lysates from either stimulated or unstimulated cells. The 85 kDa regulatory subunit of PtdIns 3‐kinase, which normally serves as a substrate for tyrosine kinases, was not detected by SDS‐PAGE or Western blot analysis in antiphosphotyrosine immunoprecipitates. In addition, no radioactive band corresponding to PtdIns 3‐kinase was observed by SDS‐PAGE following antiPtdIns 3‐kinase immunoprecipitations. However, immunoprecipitates using polyclonal antibodies against PtdIns 3‐kinase showed high PtdIns 3‐kinase activity in neutrophil lysates and the 85kDa subunit of PtdIns 3‐kinase was detected in Western blots; no differences in activity were observed in FMLP‐stimulated and unstimulated cells. These results suggest that, in contrast to polypeptide growth factor signal transduction systems, the activation of PtdIns 3‐kinase by FMLP does not require tyrosine phosphorylation.
DNA base modifications in chromatin of human cancerous tissues
Authors: Olinski Ryszard , Zastawny Tomasz , Budzbon Jaroslaw , Skokowski Jan , Zegarski Wojtek , Dizdaroglu Miral
Published: July 2002

Free radical‐induced damage to DNA in vivo is implicated to play a role in carcinogenesis. Evidence exists that DNA damage by endogenous free radicals occurs in vivo, and there is a steady‐state level of free radical‐modified bases in cellular DNA. We have investigated endogenous levels of typical free radical‐induced DNA base modifications in chromatin of various human cancerous tissues and their cancer‐free surrounding tissues. Five different types of surgically removed tissues were used, namely colon, stomach, ovary, brain and lung tissues. In chromatin samples isolated from these tissues, five pyrimidine‐derived and six purine‐derived modified DNA bases were identified and quantitated by gas chromatography/mass spectrometry with selected‐ion monitoring. These were 5‐hydroxy‐5‐methylhydantoin, 5‐hydroxyhydantoin, 5‐(hydroxymethyl)uracil, 5‐hydroxycytosine, 5,6‐dihydroxycytosine, 4,6‐diamino‐5‐formamidopyrimidine, 8‐hydroxyadenine, xanthine, 2‐hydroxyadenine, 2,6‐diamino‐4‐hydroxy‐5‐formamidopyrimidine, and 8‐hydroxyguanine. These compounds are known to be formed typically by hydroxyl radical attack an DNA bases. In all cases, elevated amounts over control levels of modified DNA bases were found in cancerous tissues. The amounts modified bases depended on the tissue type. Lung tissues removed from smokers had the highest increases of modified bases above the control levels, and the highest overall amounts. Colon cancer tissue samples had the lowest increases of modified buses over the control levels. The results clearly indicate higher steady‐state levels of modified DNA bases in cancerous tissues than in their cancer‐free surrounding tissues. Some of these lesions are known to be promutagenic, although others have not been investigated for their mutagenicity. Identified DNA lesions may play a causative role in carcinogenesis.
IL‐4 inhibits LPS‐, IL‐1β‐ and TNFα‐induced expression of tissue factor in endothelial cells and monocytes
Authors: Herbert J.M. , Savi P. , Laplace M.C. , Lale A.
Published: July 2002

Inflammatory mediators such as endotoxin, interleukin‐1β(IL‐1β) and tumor necrosis factors‐α (TNF‐α) dose‐dependently increased the expression of tissue factor on the surface of cultured bovine aortic endothelial cells (ABAE), human umbilical vein endothelial cells (HUVEC) and human monocytes. In ABAE, endotoxin‐, IL‐1β‐ and TNFα‐induced tissue factor expression was suppressed by interleukin‐4 (IL‐4) which also neutralized the pyrogenic effect of endotoxin in HUVEC and monocytes. IL‐4 did not alter TNF‐α‐induced procoagulant changes in HUVEC and monocytes but strongly protected the monocyte surface against IL‐1β‐induced procoagulant changes.
Cloning of the human taurine transporter and characterization of taurine uptake in thyroid cells
Authors: Jhiang Sissy M. , Fithian Linda , Smanik Patricia , McGill Jeffrey , Tong Qiang , Mazzaferri Ernest L.
Published: July 2002

A cDNA clone encoding a taurine transporter, designated HTAU, has been isolated from human thyroid. It contains an open reading frame encoding a protein of 619 amino acids with a calculated molecular weight of 69,675 Da. The predicted amino acid sequence of HTAU is highly homologous to those of dog kidney and rat brain. The HTAU mRNA was detectable in various human tissues examined. Transient expression of HTAU in COS‐7 cells conferred a higher taurine uptake. The taurine uptake in FRTL‐5 cells appears to be regulated by thyrotropin through cAMP. Finally, a higher taurine uptake may be associated with a higher proliferation rate in some cultured cell lines.
Astacins, serralysins, snake venom and matrix metalloproteinases exhibit identical zinc‐binding environments (HEXXHXXGXXH and Met‐turn) and topologies and should be grouped into a common family, the ‘metzincins’
Authors: Bode Wolfram , Gomis-Rüth Franz-Xaver , Stöckler Walter
Published: July 2002

The X‐ray crystal structures of two zinc endopeptidases, astacin from crayfish, and adamalysin II from snake venom, reveal a strong overall topological equivalence and virtually identical extended HEXXHXXGXXH zinc‐binding segments, but in addition a methionine‐containing turn of similar conformation (the ‘Met‐turn’), which forms a hydrophobic basis for the zinc ion and the three liganding histidine residues. These two features are also present in a similar arrangement in the matrix metalloproteinases (matrixins) and in the large bacterial Serratia proteinase‐like peptidases (serralysins). We suggest that these four proteinases represent members of distinct subfamilies which can be grouped together in a family, for which we propose the designation, metzincins.