bluuebunny/crossref_metadata_2025 huggingface dataset:
Streptococcus pneumoniae serotype 3 genotypes in invasive isolates from Colombia
Authors: Alarcón Zonia Katerin , Duarte Carolina , Sanabria Olga , Moreno Jaime
Published: June 2021

Introduction: Streptococcus pneumoniae serotype 3 is an important cause of pneumonia, bacteremia, and meningitis.Objective: To establish the circulating genotypes of S. pneumoniae serotype 3 isolates recovered from the invasive disease between 1994 to 2015 in Colombia.Materials and methods: Of the 365 S. pneumoniae serotype 3 isolates recovered through the laboratory national surveillance program, 117 isolates were analyzed. Pulsed-field gel electrophoresis was used for genotyping, and multilocus sequence typing was determined in representative isolates.Results: The frequency of this serotype increased from 2.7% between 1994 and 1998 to 9.1% between 2011 and 2015 (p=0.000); 91.7% of the isolates showed a genetic similarity greater than 77% and were related to the Netherlands3-31(PMEN31) clone CC180. Several subtypes were identified, two of which showed antimicrobial resistance.Conclusion: In Colombia, the pneumococcal population of the capsular type 3 shows a continuous and homogeneous circulation relating to the clonal group ST-180.
Seroprevalence of arboviruses in Ecuador: Implications for improved surveillance
Authors: Gutiérrez-Vera Ernesto , Patiño Leandro , Castillo-Segovia Martha , Mora-Valencia Víctor , Montesdeoca-Agurto Julio , Regato-Arrata Mary
Published: June 2021

Introduction: Arthropod-borne viruses (arboviruses) cause morbidity and mortality in humans and domestic animals worldwide. The percentage of population immunity or susceptibility to these viruses in Ecuador is unknown.Objectives: To investigate the proportion of Ecuadorian populations with IgG antibodies (Abs) (past exposure/immunity) and IgM Abs (current exposure) against flaviviruses and alphaviruses and to study the activity of these viruses in Ecuador.Materials and methods: During 2009-2011, we conducted a serosurvey for selected arboviruses in humans (n=1,842), equines (n=149), and sentinel hamsters (n=84) at two coastal locations and one in the Amazon basin (Eastern Ecuador) using enzyme-linked immunosorbent assay and hemagglutination inhibition test.Results: From 20.63% to 63.61% of humans showed IgG-antibodies for the flaviviruses: Dengue virus (DENV), yellow fever virus (YFV) Saint Louis encephalitis virus, and West Nile virus (WNV); from 4.67% to 8.63% showed IgG-Abs for the alphaviruses: Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus. IgM-Abs were found for DENV and WNV. Equines and hamsters showed antibodies to alphaviruses in all locations; two hamsters seroconverted to YFV in the Amazonia.Conclusions: The results show a YFV vaccination history and suggest the activity of arboviruses not included in the current surveillance scheme. Enhanced arbovirus and mosquito surveillance, as well as continued YFV vaccination and evaluation of its coverage/effectiveness, are recommended.
Effects of mannan oligosaccharides on growth performance, nutrient digestibility, ruminal fermentation and hematological parameters in sheep
Authors: Zheng Chen , Zhou Juwang , Zeng Yanqin , Liu Ting
Published: June 2021

Background

Mannan oligosaccharides (MOS) are a promising feed additive in animal husbandry due to mainly improving animal health status. The purpose of this study was to investigate the effects of MOS on growth performance, nutrient digestibility, ruminal fermentation, and twelve hematological parameters in sheep.

Methods

Ninety-six healthy Hu rams with similar body weights were chosen and divided into four treatment groups (twenty-four rams in each group), in which four different doses of MOS were tested: 0%, 0.8%, 1.6% and 2.4% of the basal diet (on an as-fed basis).

Results

The results showed that supplementation dietary MOS did not affect feed intake, body weight, average daily weight gain, or ruminal short-chain fatty acids (SCFAs) concentration; the ratio of individual fatty acids to total SCFAs, the C2/C3 ratio, and the hematological parameters in the sheep were also unaltered (P > 0.05). Conversely, supplementation dietary MOS increased the dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber, and ash apparent digestibility (P < 0.05), and decreased the ruminal ammonia concentration in the sheep (P < 0.05), especially at a dose of 1.6%.

Conclusions

This indicates that supplementation dietary MOS improved nutrient utilization by the sheep and nitrogen metabolism in the rumen; however, the effects are too slight to interfere with the basal metabolism in the sheep.
New austrolimulid from Russia supports role of Early Triassic horseshoe crabs as opportunistic taxa
Authors: Bicknell Russell D.C. , Shcherbakov Dmitry E.
Published: June 2021

Horseshoe crabs are extant marine euchelicerates that have a fossil record extending well into the Palaeozoic. Extreme xiphosurid morphologies arose during this evolutionary history. These forms often reflected the occupation of freshwater or marginal conditions. This is particularly the case for Austrolimulidae—a xiphosurid family that has recently been subject to thorough taxonomic examination. Expanding the austrolimulid record, we present new material from the Olenekian-aged Petropavlovka Formation in European Russia and assign this material toAttenborolimulus superspinosusgen. et sp. nov. A geometric morphometric analysis of 23 horseshoe crab genera illustrates that the new taxon is distinct from limulid and paleolimulid morphologies, supporting the assignment within Austrolimulidae. In considering Triassic austrolimulids, we suggest that the hypertrophy or reduction in exoskeletal sections illustrate how species within the family evolved as opportunistic taxa after the end-Permian extinction.
Studies on compressive strength of sandy clay soil samples with different percentages of lime and nylon fibres
Authors: Athira T , Sini T
Published: June 2021

To develop economically feasible and durable methods of ground improvement are some of the major challenges faced by geotechnical engineers. Many commonly available stabilisers like lime, fly ash, rice huskash has been used in many studies. These stabilisers are known to improve the compressive strength of soil. But in order to improve the tensile properties of soil and increase the ductility characteristics, fibres can be included along with the commonly used stabilisers. In this paper values of compressive strength of sandy clay soil treated with different concentrations of lime and nylon fibre is studied and compared with the values of untreated native soil. The compressive strength of soil increases withincrease in lime content up to 10%. The compressive strength of soil also increases with nylon fibre inclusion up to a concentration of 0.3%. With further increase in nylon fibre content, compressive strength decreases in the studied samples. In the present study the difference in the increase in compressive strength shown by composites with random and horizontal layers of nylon fibres as inclusions appears to be very small. The present study concludes that a combination of lime and nylon fibre can be a better stabilizer for ground improvement.
Modern trends in design ofHigher educational institutions of Ukraine.
Authors: Kryzhantovskaya Oksana
Published: June 2021

The article deals with the problems of architectural and town-planning issues when creating and building buildings of higher educational institutions (hereinafter-HEIs) of Ukraine. The approaches to construction of the functional structure of the external and internal environments of the HEI of the architectural and planning, educational and laboratory blocks, three-dimensional spatial resources are analyzed.
Material flow in construction sites –a case study.
Authors: Babu Sruthi Suresh , Eldhose Sahimol
Published: June 2021

The efficient movement of materials at sites in fair quantity at fair time without any interruption is called material flow. Operation and flow of these materials is a challenge experienced in sites today due to material scarcity, delivery delays, inadequate transportation facilities, loss and wastage, insufficient storage space etc. Data on material flows and inventory levels is intended to promote circular economy and resourceefficiency in the construction sector. This paper presents a case study in Kerala, India with the purpose to quantify the flow of materials and stocks in the construction site. A questionnaire survey was conducted to find out the main factors that can affect the flow of materials in the building industry. Out of 65 respondents labour, equipment, material, time and cost are identified as the main factors which can contribute towards material flow. Based on the identified parameters, a material flow pathway is developed for the case study. It demonstrates the management of logistics andfactors influencing the movement of materials on work sites. It therefore helps in the analysis of factors concerning the efficient use of materials in infrastructure projects.
Scenario analysis of fluoride contamination in the groundwater in Kerala.
Authors: Jeyalakshmi Saranya , Beegum Sahila
Published: June 2021

The Kerala State is a narrow strip of land in the southwest of India,with the Arabian Sea on the west and the Western Ghats in the east. Recent studies related to contaminant transport in the soil and groundwater in Kerala have reported Fluoride contamination in the aquifers. Due to the poor quality of the surface water sources in the state, the majority of the population in the state depends on groundwater resources for domestic and agricultural uses. When using groundwater for domestic purposes, it is highly important to analyzethe quality of the groundwater. This study focuses on the analysis of the Fluoride transport in the soil and groundwater intwo different lithological units(laterite and coastal alluvium)in the State. The study concluded that the aquifer in coastal alluvium formation is more susceptible to Fluoride contamination compared to the laterite formation.
Quantitative risk analysis procedure for economic project sustainability.
Authors: Shaji Jithin Arakkatt
Published: June 2021

The paper briefly explains the importance of quantitative procedures of risk analysis in large and medium scale projects for the sustenance of project economic sustainability. Globally, several construction projects are being descoped and tend to close out before attaining the initial project deliverables due to cost and schedule overruns. The quantitative methods can sieve the key factors and forecast the tangible impacts that can lead to schedule or cost variance in a project. It can guide the project stakeholders for timely decision making and mitigate the risks associated to achieve the project goals. Today, the quantitative methods are pivotal to analyze the impacts of Covid-19 crises in Construction industry which are increasingly apparent.
Numerical investigation on cold formed steel angle section portal frames.
Authors: Santhosh Devika , Prassad Lakshmi
Published: June 2021

Cold formed steel portal frames are widely used as alternative to traditional portal frames made from hot rolled steel sections. Load-displacement response of cold formed steel single C-section portal frames is available. C-section portal frames undergo significant deformation before reaching their ultimate loads. In this study, cold formed steel angle portal frame is analyzed using finite element analysis in order to find the load-displacement response. Bolt pressure is applied at the location of physical bolts in ANSYS.
Review on investigation of corrosion behavior of reinforced concrete with supplementary cementitious materials.
Authors: Aavani K U , Aneesha A , Baby Xavier Thomas , Vandana S , Anju Paul
Published: June 2021

Cement concrete is the most widely used material for various constructions. Properly designed and prepared concrete results in good strength and durability. Sometimethese mixes are found to be inadequate, hence variety of admixtures are used along with cement. A certain percentage of cement will be replaced separately with metakaolin and silica fumes. Hence the flexural strength test of concrete and evaluation of corrosion behavior of the reinforcement can be performed. The study of flexural property of concrete will be conducted at 7 or 28 days characteristic strength with different replacement level of cement(i.e.0%,5%,10%,15%,20%). Corrosion behavior of reinforcement will be evaluated based on half-cellpotential. Concrete samples will be cured in either fresh water of 4% NaCl saline water for 7 or 28 days of curing period. We assumed that the addition of silica fumes and metakaolin will improve the flexural strength characteristics of concrete and corrosion resistivity of reinforcement.
Life below water and the fate of humanity: with special reference to the efforts by Adidas towards reducing the effects of plastic waste on the marine life.
Authors: Joshi Sonali , Temgire Smita
Published: June 2021

Marine Pollution is all the human waste in terms of chemicals, unwanted substances, non-biodegradable waste such as plastic that is thrown into the Earth’s water. The origin of the marine pollution is varied human activity that takes place on land. Whereinindustrialization on one has shown immense growth in the life of human beings on this planet, taking them to the era being ruled by artificial intelligence, this rapid and unprecedented growth has also lead to the demolish of the treasures of our oceans and water bodies. The Pacific Ocean has a plastic “garbage patch” of approximately 6, 20,000 sq miles. The plastic pollution, notedly, is the most harmful of the other pollution sources as it directly affects the life of corals through fibres, poisoning andtrapping of sea animals in nets, wires etc. In 1972, London Convention was the first international agreement on protecting the oceans and the oceanic life. The 2006 London Protocol bans all the hazardous waste from being disposed in the sea. Companies like Adidas have started finding solutions to control, if not yet eliminate, hazardous human actions.
Water-related impacts on agriculture due to climate change: a review with reference to Kerala.
Authors: Thomas Niranjana , James E.J , George Celine
Published: June 2021

Climate change has arisen as the most pressing global challenge of the 21st century. The impending challenges may be associated with water resources management. Water-related impacts due to climate change areranging from water scarcity to intense floods. The stateof Kerala has witnessed severe floods inthelast two years owing to Extreme Rainfall Events (ERE), among which the prominent ones arethe events thatoccurred in August 2018. The extent of human and livestock mortalities, crop damages and economic lossesdue to the floods was enormous. This paper critically reviews the scientific studies and reports on impacts of climate change which profiting generalists bothered with environmental challenges. The article highlights the need for water conservation, risk management, and the development of mitigation measures to cope withthe water-related impacts of climate change on agriculture.
Review on carbon capture and storage for construction engineering.
Authors: Yedulakshmi Nair , George Elba Helen
Published: June 2021

Global warming and climatic changes due to pollution have triggered the global efforts to reduce the concentration of atmospheric carbon dioxide. The carbon dioxide capture and storage method is considered as a strategy or plan of action for meeting carbondioxide emission reduction targets. This paper aims at providing an intensive review of various carbon capture and storage techniques, transportation of carbon dioxide & the utilization of this captured carbon dioxide in the construction industry. It alsoprovides a huge perception of the manufacturing process of various construction materials using carbon dioxide. This review may present a clear understanding of the carbon upcycling technologies & everything we do is geared towards a goal of creating a circular economy & awaken new ideas to promote its practical application in construction materials.
Laterite as a base and subbase material for flexible pavement –a review.
Authors: Jayalekshmi a S. , Fernandez Lincy , Faustine Anooja , Anjana A , Pai Rahul. R.
Published: June 2021

Rapid economic growth is leading to ubiquitous expansion in highway projects around the world. Utilization of natural aggregateresources for the construction of flexible pavement has led to uncontrollable quarrying in the state of Kerala. The recent landslides in Kerala which took the lives of many people is the aftermath of extensive quarrying activities. Utilization of treated native soil in the structural layers (Subbase and base) of flexible pavement can widely avert the danger associated with ecological imbalance due to quarrying. The main objective of this review article is to enlighten the researchers and practicing engineers about the key advances developed in the last 10 years for utilizing native laterite soil in the base and subbase layers of flexible pavement. On the basis of various researches, laterite soil treated with lime, cement andother additives showed considerable enhancement in the compaction characteristics, unconfined compressive strength (UCS) and California Bearing Ratio (CBR). As stipulated by MORTH (Ministry of Road Transport and Highways), for a layer to be suitable as a subbase material in flexible pavement, minimum CBR value must be 30%. From the extensive review, it was found that the treated laterite soil satisfied the MORTH criteria for use as a subbase layer in flexiblepavement.
Membrane potential (Δψ) depolarizing agents inhibit maturation
Authors: Pagès Jean-Marie , Lazdunski Claude
Published: July 2002

Precursor forms of exported proteins were first accumulated in the envelope of phenethyl alcohol (PEA)‐treated cells. After removal of PEA, a complete processing could be obtained in a few minutes. In this work, we demonstrate that colicins A and E1, that act on the electrical gradient in the cytoplasmic membrane, prevent the processing of precursor forms previously accumulated. Concentrations of colicins accounting for ∼1 killing unit (50–3000 molecules/cell) were found to be sufficient for inhibition of processing. Therefore our results strongly suggest that in intact cells the electrical gradient across the cytoplasmic membrane is required for maturation of exported proteins.
Requirement for a reduced sulphydryl entity in the protection of molybdate‐stabilized estrogen receptor
Authors: Ratajczak T. , Samec A.M. , Hähnel R.
Published: July 2002

The separate and combined effects of molybdate and dithiothreitol on the stability of human uterine 9 S estrogen receptor were studied. Maximal, short‐term, protection of the 9 S estrogen receptor was achieved by the joint inclusion of both stabilizing agents in cytosol buffers. This molybdate—dithiothreitol‐mediated stability was dependent on reducing agent concentration inferring sulphydryl involvement in 9 S receptor protection by molybdate. The study also showed that molybdate—dithiothreitol could not prevent the gradual decay of the 9 S estrogen receptor to the 4 S form in cytosols stored at 4°C over prolonged periods.
Mechanism of caffeine‐induced inhibition of DNA synthesis in Escherichia coli
Authors: Sandlie Inger , Lossius Ivar , Sjåstad Knut , Kleppe Kjell
Published: July 2002

Caffeine inhibited DNA synthesis in toluene‐treated Escherichia coli K 12 strains to the same extent as in intact cells using the incorporation of [3H]thymidine as a measure of DNA synthesis. The inhibition was found to be competitive with ATP, and it was not influenced by the concentrations of deoxynucleoside triphosphates to any extent. When caffeine was added together with other DNA synthesis inhibitors such as novobiocin, nalidixic acid or actinomycin D, the inhibition in all cases was non‐additive. It is suggested that caffeine inhibits one of the ATP‐requiring enzymes in the DNA replication machinery, possibly DNA polymerase III or one of the DNA helicases.
Red blood cell targeting to collagen‐coated surfaces
Authors: Samokhin G.P. , Smirnov M.D. , Muzykantov V.R. , Domogatsky S.P. , Smirnov V.N.
Published: July 2002

The interaction of human red blood cells carrying antihuman collagen antibody with collagen‐coated surfaces was studied. Avidin was used as bifunctional crosslinking agent for the attachment of antibody to the red blood cell surface. Antibody‐carrying red blood cells efficiently and specifically bound to collagen‐coated surface covering a significant part of the surface. The components of normal blood had an insignificant effect on red blood cell binding. A model of drug targeting to the injured sites(s) of blood vessel wall is proposed.
Monomeric pituitary growth hormone and prolactin variants in man characterized by immunoperoxidase electrophoresis
Authors: Meuris Sylvain , Svoboda Michal , Vilamala Maria , Christophe Jean , Robyn Claude
Published: July 2002

Immunoperoxidase electrophoresis, combining SDS‐ME‐PAGE and the ‘double bridge’ immunoperoxidase staining was applied to crude human pituitary homogenates. With anti‐hGH and anti‐hPL sera, 4 hGH‐related monomers were characterized: a M
r 22 000 peptide corresponding to hGH; a M
r 20 000 peptide corresponding to the known hGH variant and two unknown hGH variants (M
r 65 000 and M
r 75 000). With anti‐ovine, rat and human PRL sera, 4 PRL‐related monomers were immunostained: one comigrated with purified hPRL (M
r 25 000), and 3 were unknown (M
r 29 000; M
r 45 000; M
r 16 000).
Effect of papain digestion on redox‐linked proton translocation in b‐c1 complex from beef heart reconstituted into liposomes
Authors: Lorusso M. , Gatti D. , Marzo M. , Papa S.
Published: July 2002

Papain treatment of the cytochrome b‐c
1 complex from beef heart results in partial proteolysis of core protein II, the iron‐sulphur protein and the 15‐kDa subunit. Under these conditions a significant inhibition of electron flow and complete suppression of proton translocation in the complex reconstituted into liposomes are observed. Kinetic experiments indicate a correlation between the digestion of core protein II and 15‐kDa subunit and the suppression of proton translocation. The results suggest an active involvement of polypeptides of the complex in stabilizing the semiquinone species and/or providing pathways to exchange protons between bound quinone systems and aqueous phases.
Relaxation of PvuII recognition sequence
Authors: Nasri Moncef , Sayadi Sami , Thomas Daniel
Published: July 2002

The substrate specificity of PvuII endonuclease is relaxed in the presence of dimethyl sulfoxide. The new recognition sequences cleaved in pBR322 DNA have been found to be CCGCTG, CATCTG, CAGATG, CAGGTG and CAGCGG.
Conservation from rat to human of cytosolic phosphoenolpyruvate carboxykinase and the control of its gene expression
Authors: Cohen Hannah , Gidoni Bruriah , Shouval Daniel , Benvenisty Nissim , Mencher David , Meyuhas Oded , Reshef Lea
Published: July 2002

Structural conservation of cytosolic phosphoenolpyruvate carboxykinase protein and mRNA sequence was found in all species examined from rodents to human. The mitochondrial isoenzyme, in all species tested, represents a distinct protein. Moreover, irrespective of the ratio of cytosolic to mitochondrial isoenzyme, cytosolic phosphoenolpyruvate carboxykinase activity in the human as in the rat is controlled at the level of gene expression and through the same multiple hormonal stimulation. This evolutionary conservation of the cytosolic phosphoenolpyruvate carboxykinase structure and mode of regulation supports the enzymes' physiological importance in mammals.
The primary structures of the A4 and A5 subunits are highly homologous to that of the A3 subunit in the glycinin seed storage protein of soybean
Authors: Hirano Hisashi , Fukazawa Chikafusa , Harada Kyuya
Published: July 2002

The A5 subunit of the glycinin seed storage protein of soybean was purified by ion‐exchange chromatography followed by preparative SDS‐gel electrophoresis and the complete amino acid sequence was determined. The A5 subunit is composed of 97 amino acids which correspond to an M
r of ~10600. Approx. 86% of the sequence of the A5 subunit was found to be identical to that of the NH2‐terminal region of the A3 subunit of the glycinin determined previously. Also, the A4 subunit of the glycinin was purified and the partial sequence was determined. The sequence of the A4 subunit was estimated to be highly homologous to that of the COOH‐terminal region of the A3 subunit.
The effect of gramicidin on ATP synthesis in pea chloroplasts: two modes of phosphorylation
Authors: Opanasenko V.K. , Red'ko T.P. , Kuz'mina V.P. , Yaguzhinsky L.S.
Published: July 2002

The effect of gramicidin on the phosphorylation rate, electron flow and light‐induced H2+ uptake (ΔH+) in chloroplasts with methyl viologen (MV) or phenazine methosulfate (PMS) added has been studied. In the presence of MV low concentrations of gramicidin (~10−9 M) were shown to inhibit the phosphorylation rate up to 80–90% of the initial value, without changing either the electron transport rate or ΔH+ value. Two components of phosphorylation have been identified in the presence of PMS ‐ the first is DCMU‐sensitive, which was suppressed by low gramicidin concentrations (< 10−9 M) and the second ‐ DCMU‐insensitive component, which was suppressed by high gramicidin concentrations (~10−7 M) exclusively, the high gramicidin concentration inducing the ΔH+ value fo fall.
Stimulation of parathyroid hormone secretion by phorbol esters is associated with a decrease of cytosolic calcium
Authors: Muff R. , Fischer J.A.
Published: July 2002

Unlike in other endocrine systems calcium inhibits parathyroid hormone (PTH) secretion and this inhibition is paralleled by a rise of cytosolic calcium concentration ([Ca]i). Because of evidence that diglyceride levels and protein kinase C activity are also decreased by high extracellular calcium we have investigated the effects of 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), an activator of protein kinase C, on [Ca]i and PTH secretion using dispersed bovine parathyroid cells. At 1.5 mM medium calcium TPA enhanced PTH secretion and caused reduction of [Ca]i from 639 ± 36 nM (SE) to 335 ± 21 nM (P < 0.001); at 0.5 mM calcium TPA was ineffective. Moreover, TPA suppressed the rise of [Ca]i evoked by high extracellular calcium. Thus TPA presumably stimulates PTH secretion via activation of protein kinase C, and the lowering of [Ca]i may be a secondary event related to diglyceride availability.
Resonance Raman evidence for an exchangeable protein hydrogen associated with the heme a group of cytochrome oxidase
Authors: Copeland Robert A. , Spiro Thomas G.
Published: July 2002

When cytochrome–c oxidase is soaked in D2O, downshifts of the cytochrome a formyl C=O stretching mode are seen in the resonance Raman (RR) spectra (413.1 nm excitation) of both the resting and reduced forms. Other changes observed in the reduced protein RR spectra are consistent with involvement of the cytochrome a formyl group in the deuterium effect. The D2O–induced RR changes are fully developed during 3–5 days incubation, but are incomplete after 1 h. Extraction of the heme a chromophore in deuterated solvents eliminates these changes, implying that the exchangeable proton is on a protein group in the cytochrome a pocket which H–bonds to the heme formyl. The rate of the D2O exchange process is unaffected by enzyme turnover, thus reducing the likelihood that the cytochrome a formyl H–bond is directly involved in the redox–linked mechanism of proton pumping.
Synthesis of cell‐impermeable inhibitor of phospholipase A2
Authors: Yedgar Saul , Reisfeld Nurit , Dagan Arie
Published: July 2002

Phospholipase A2 (PLA2) in the cell surface membrane is considered a regulator of cellular secretion. The distinction between the role of the cell surface and the intracellular PLA2 is not clear, since it has not been possible to differentiate unequivocally the activity of the enzymes in the various organelles. The use of an extracellular inhibitor of PLA2 can greatly contribute to the understanding of cell surface PLA2 function. In this paper, the preparation of a cell‐impermeable inhibitor of PLA2 is presented. This substance incorporates into lipid membranes and is capable of blocking the hydrolysis of membrane phospholipids by snake venom as well as by cell membrane PLA2.
Affinity labelling of Escherichia coli ribosomes with a benzylidene derivative of AUGU6 within initiation and pretranslocational complexes
Authors: Babkina G.T. , Veniaminova A.G. , Vladimirov S.N. , Karpova G.G. , Yamkovoy V.I. , Berzin V.A. , Gren E.J. , Cielens I.E.
Published: July 2002

Affinity labelling of E. coli ribosomes with the 2',3'‐O‐[4‐(N‐2‐chloroethyl)‐N‐methylamino]benzylidene derivative of AUGU6 was studied within the initiation complex (complex I) obtained by using fMet‐tRNAf
Met and initiation factors and within the pretranslocational complex (complex II) obtained by treatment of complex I with the ternary complex Phe‐tRNAPhe‐GTP‐EF‐Tu. Both proteins and rRNA of 30 S as well as 50 S subunits were found to be labelled. Sets of proteins labelled within complexes I and II differ considerably. Within complex II, proteins S13 and L10 were labelled preferentially. On the other hand, within complex I, multiple modification is observed (proteins S4, S12, S13, S14, S15, S18, S19, S20/L26 were found to be alkylated) despite the single fixation of a template in the ribosome by interaction of the AUG codon with fMet‐tRNAf
Met.
Stucture of phosphoenolpyruvate carboxylase from maize leaves
Authors: Stiborová Marie , Leblová Sylva
Published: July 2002

Phosphoenolpyruvate carboxylase (PEPC) from maize leaves has an M
r of 400000. The native enzyme molecule is a homotetramer. The amino acid composition of PEPC is determined. The enzyme contains 8 half‐cystine residues per subunit. The role of half‐cystine residues and the steric arrangement of the enzyme protein molecule are discussed.
Aggregation of plasma Z type α1‐antitrypsin suggests basic defect for the deficiency
Authors: Cox D.W. , Billingsley G.D. , Callahan J.W.
Published: July 2002

The abnormal type of α1‐antitrypsin, PI (protease inhibitor) type Z, is associated with inclusion bodies in the liver, which contain non‐secreted α1‐antitrypsin. Our studies show that Z protein has an inherent tendency to aggregate, even in plasma. Depending upon conditions, from 15 to 70% of the Z protein in plasma was in a high‐Mrform, compared with 1.5% of M type α1‐antitrypsin. The high‐Mrcomplex in plasma cannot be disaggregated using Triton X detergent or reducing conditions. This increased tendency to aggregate can be explained by the mutation affecting, tertiary structure and salt bridge formation in Z protein. We have observed this same tendency to aggregate for Mmalton α1‐antitrypsin, a rarer variant also associated with a plasma deficiency.
Structural relationships between the NADH dehydrogenases of Paracoccus denitrificans and bovine heart mitochondria as revealed by immunological cross‐reactivities
Authors: George Christina L. , Ferguson Stuart J. , Cleeter Michael W.J. , lan Ragan C.
Published: July 2002

An antibody raised against two subunits (M
r, 48000 and 25000) of NADH dehydrogenase from Paracoccus
denitrificans cross‐reacts with one of more than 20 polypeptides that form the bovine heart mitochondrial NADH dehydrogenase. The cross‐reacting subunit has M
r, 51000 and is believed to be the NADH‐binding subunit of the enzyme. Antibodies raised against certain subunits of the bovine heart NADH dehydrogenase were tested for cross‐reactivity withP. denitrificans cytoplasmic membranes. Of those tested, only one, an antibody specific for the 49 kDa subunit of mitochondrial NADH dehydrogenase, cross‐reacted with the bacterial membranes. It recognised a polypeptide of approximate M
r, 46000. This is an indication for a previously undetected third subunit of NADH dehydrogenase from P. denitrificans. The immunological crossreactions indicate that the NADH dehydrogenases from P. denitrificans and bovine heart mitochondria are related structurally.
Regulation of low density lipoprotein metabolism by 26‐hydroxycholesterol in human fibroblasts
Authors: Lorenzo José L. , Allorio Maria , Bernini Franco , Corsini Alberto , Fumagalli Remo
Published: July 2002

Oxygenated derivatives of cholesterol are believed to play a role in cellular cholesterol homeostasis through the feed‐back control of its biosynthesis. We report that 26‐hydroxycholesterol inhibits the specific binding, uptake and degradation of 125I‐LDL in human fibroblasts. The effect is dose‐dependent, and saturation kinetics indicates a reduction of LDL‐binding sites with no effect on ligand affinity. The results support a possible role of 26‐hydroxycholesterol, a physiological oxysterol, in the regulation of cellular cholesterol homeostasis.
Structure of the porin from a bacterial stalk
Authors: Chalcroft J.P. , Engelhardt H. , Baumeister W.
Published: July 2002

The stalks (hyphae) of a prosthecate bacterium, directly sampled from the water surface of a hot pond, show extended regular patterns on their envelope in the electron microscope. Image processing revealed a structure of the crystalline complexes which is very similar to the gross morphology of the Escherichia coli porins OmpC and OmpF. The natural two‐dimensional crystal of the outer membrane protein has p3 symmetry and a lattice constant of 7.95 nm. The three‐dimensional structure of the stalk porin has been determined to an almost isotropic resolution of 1.7 nm. The reconstruction revealed a complex network of channels within the membrane matrix with a triplet of pores merging into a common outlet, similar to the structure of the E. coli porin OmpF in reconstituted membranes. In addition, a blindly ending pore exists which appears to be connected to the continuous pores via small channels. The significance of the regularly arrayed porin cylinders with respect to the shape and function of the stalks is discussed.
Synthesis of the growth hormone‐regulated rat liver anti‐protease GHR‐P63 is inhibited by acute inflammation
Authors: Le Cam Ginette , Le Cam Alphonse
Published: July 2002

Synthesis of the growth hormone‐regulated anti‐protease GHR‐P63 by rat hepatocytes was strongly reduced during acute inflammation. This decrease was detected 8 h after the onset of inflammation and reached a maximum after 24 h. A decrease in the GHR‐P63 mRNA level measured by in vitro translation and by hybridization mainly accounted for the alteration of GHR‐P63 synthesis. Besides this major pretranslational mechanism, inflammation also interfered with GHR‐P63 synthesis at a posttranslational level. This was indicated by the production of abnormal immunoprecipitable species at early stages of the acute‐phase response.
Proteolysis of Paracoccus denitrificans cytochrome oxidase by trypsin and chymotrypsin
Authors: Finel Moshe
Published: July 2002

Paracoccus oxidase containing only two subunits was subjected to proteolysis by trypsin and chymotrypsin. Both subunits in the purified enzyme were cleaved at only a few sites and enzymatic activity was not inhibited. The cleavage sites were identified by protein sequencing. Subunit I was cleaved near the amino‐terminus and subunit II in the loop connecting the two predicted trans‐membrane helices. In native membrane fragments, but not in intact spheroplasts, this loop was accessible to both proteases. These results provide experimental evidence for the folding of subunit II in the membrane.
500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d6 by two‐dimensional techniques
Authors: Di Bello Carlo , Gozzini Luigia , Tonellato Mauro , Corradini Maria Grazia , D'Auria Gabriella , Paolillo Livio , Trivellone Enrico
Published: July 2002

The proton NMR characterization of bombesin has been carried out at 500 MHz in DMSO‐d6 using two‐dimensional homo‐ and 1H‐13C hetero‐correlated techniques. All resonances in the NMR spectra have been assigned and several coupling constants have been measured. The backbone J
αCH‐NH coupling constants have constant values that vary between 7.8 and 8.2 Hz and indicate an unfolded structure in DMSO‐d6. Discrepancies with data recently obtained at 300 MHz [(1987) Eur. J. Biochem. 168, 193–199] are discussed.
Human interferon‐γ lacking 23 COOH‐terminal amino acids is biologically active
Authors: Sakaguchi Masao , Honda Susumu , Ozawa Mariko , Nishimura Osamu
Published: July 2002

We constructed five mutated cDNAs encoding human interferon‐γ (IFN‐γ) derivatives lacking 19–23 COOH‐terminal residues and expressed them in Escherichia coli. All the derivatives were purified to homogeneity. They showed substantially the same order of antiviral activity in vitro as the intact molecule, and behaved as a dimer. The far‐ and near‐UV circular dichroism spectra of the derivatives were quite similar to those of the intact one. These results indicate that the 23 COOH‐terminal amino acids at least are not essential for achieving the full antiviral activity and constructing the higher structure of human IFN‐γ.
Strategy of research on the chemiosmotic mechanism of cytochrome oxidase
Authors: Mitchell Peter
Published: July 2002

In recent papers on protonmotive redox mechanisms in cytochrome oxidase in [(1987) FEBS Lett. 222, 235–245] and [Glynn Biological Research Reports (1987) 3, 1–7], I have suggested that a copper centre may enable the H2O/OH or H2O/O couple to act as the hydrogen‐carrying arm of a redox loop by means of a (CuOH2)+/(CuOH)+ or (CuOH2)+/ (CuO)+ system at the centre. I here explain that critical comments by Malmström [(1988) FEBS Lett. 231, 268–269] on the first of these papers, which might also be levelled at the second, depend on a misunderstanding. I also respond to Malmström's comment about testing conformationally coupled proton‐pump mechanisms.
Rapid phosphorylation of a 27 kDa protein induced by tumor necrosis factor
Authors: Hepburn Anne , Demolle Dominique , Boeynaems Jean-Marie , Fiers Walter , Dumont Jacques E.
Published: July 2002

Tumor necrosis factor (TNF) has been shown to induce the phosphorylation of a 27 kDa protein in a time‐ and concentration‐dependent manner in HeLa D98/AH2, ME 180 and bovine aortic endothelial cells. This phosphorylation could be reproduced by the calcium ionophore, A23187. However, this phosphorylation was not observed in L929 cells, for which TNF is highly cytotoxic, suggesting that it might play a role in actions of TNF other than the induction of cell death.
Counterions and the bacteriorhodopsin proton pump
Authors: Dér A. , Tóth-Boconádi R. , Keszthelyi L.
Published: July 2002

Theoretical and new experimental arguments are given to explain the reversal of photoelectric signals from purple membranes oriented and immobilized in gel due to the presence of TEMED. The continuous current induced by continuous illumination demonstrates a photoelement‐like behaviour, the polarity of which is reversed by TEMED. The data render the counterion‐collapse mechanism highly questionable.
ATP synthesis and pyrophosphate‐driven proton transport in tonoplast‐enriched vesicles isolated from Catharanthus roseus
Authors: Dupaix Alain , Johannin Georges , Arrio Bernard
Published: July 2002

In the presence of PPi as an energy source, the tonoplast‐bound inorganic pyrophosphatase from Catharanthus roseus cells is able to create a proton‐gradient which can drive the synthesis of ATP from ADP and Pi. ATP synthesis is linked to the pH‐gradient dissipation as monitored by the recovery of the fluorescence intensity of quinacrine and by the amount of synthesized ATP measured by the bioluminescent luciferin/luciferase assay. Proton gradient and ATP synthesis were suppressed by the protonic ionophore gramicidin D.
Two physiological substrate‐specific casein kinases are present in the bovine mammary gland
Authors: Brooks Charles L.
Published: July 2002

Two species of casein kinase from lactating bovine mammary gland have been identified; a Ca2+‐ and CM‐independent casein kinase and a Ca2+‐ and CM‐dependent casein kinase. The Ca2+‐ and CM‐independent casein kinase phosphorylates previously dephosphorylated αs1‐, β‐ or κ‐casein while the Ca2+‐ and CM‐dependent casein kinase prefers previously dephosphorylated β‐ or κ‐casein as substrates. Two activities are indicated by their substrate specificity, sensitivity to Ca2+ and CM, pH maxima, and differential solubilization by anionic detergents. The presence of a regulated casein kinase in the lactating mammary gland suggests that casein phosphorylation may be a regulator of micelle formation or secretion.
Functional molecular masses of vacuolar membrane H+‐ATPase from Saccharomyces cerevisiae as studied by radiation inactivation analysis
Authors: Hirata Ryogo , Ohsumi Yoshinori , Anraku Yasuhiro
Published: July 2002

The functional molecular masses of the vacuolar membrane H+‐ATPase in Saccharomyces cerevisiae under two kinetic conditions for ATP hydrolysis were measured by radiation inactivation. When vacuolar membrane vesicles were exposed to γ‐rays from 60Co, the activities catalyzing a single‐cycle and multi‐cycles of ATP hydrolysis both decreased as single‐exponential functions of the radiation dosage. By applying the target theory, the functional molecular masses for single‐and multi‐cycle hydrolyses of ATP were determined to be approx. 0.9–1.1 × 105 and 4.1–5.3 × 105 Da, respectively. N,N′‐Dicyclohexylcarbodiimide (DCCD) did not inhibit the former reaction but strongly inhibited the latter. It is suggested that the ATPase with a minimal composite of subunits a and b, in which subunit c is not necessarily involved operationally, can catalyze single‐cycle hydrolysis of ATP, whereas for multi‐cycle hydrolysis of ATP, the ATPase requires a properly organized oligomeric structure with subunits a–c, which may direct a positive cooperative mechanism of ATP hydrolysis and coupled H+ translocation in a DCCD‐sensitive manner.
The assembly of the major desmosome glycoproteins of Madin‐Darby canine kidney cells
Authors: Penn Elizabeth J. , Hobson Christine , Rees David A. , Magee Anthony I.
Published: July 2002

Madin‐Darby canine kidney (MDCK) cells are unable to form desmosomes when cultured in low‐calcium medium ([Ca2+]<0.1 meq./l), but can be induced to do so by raising the calcium to physiological concentrations (1–2 meq./l). We have previously demonstrated that this block correlated with increased desmosomal protein turnover. Here we have immunoprecipitated the major desmosome glycoproteins [DGI (150 kDa) and DGII/III (120/100 kDa)] from non‐ionic detergent‐soluble and ‐insoluble fractions prepared from metabolically labelled MDCK cells cultured in standard or low‐calcium medium. Pulse‐chase studies showed that both DGI and DGII/III became unextractable in non‐ionic detergent before their arrival at the cell surface, whether cells were grown in standard or low‐calcium medium. The non‐ionic detergent insolubility of these membrane components is therefore a separate step which precedes the formation of morphologically recognisable desmosomes.
Raison d'être and structural model for the B‐Z transition of poly d(G‐C)∗poly d(G‐C)
Authors: Saenger Wolfram , Heinemann Udo
Published: July 2002

In DNA oligonucleotides crystallized in the A form, the nucleotides adopt standard conformation except for steps 5'‐CpG‐3' where reduced base‐pair twist and a sliding motion of the base pairs along their long axes causes pronounced interstrand guanine‐guanine overlap. As a consequence, torsion angles α,β and γ are consistently trans, trans, trans instead of the common ‐gauche, trans, + gauche. This conformation significantly increases the intraresidue distance between the guanine base and the 5'‐phosphate group. A molecular model of poly d(G‐C)·poly d(G‐C) built with these structural characteristics in the A form, which we call A2‐DNA, shows that rotation of the guanosine sugar into the syn orientation is easily achieved and pushes the base pair across the helix axis. If successive guanosines are changed this way, a smooth transformation occurs to the left‐handed Z‐DNA. We suggest that A‐ and A2‐DNA forms of poly d(G‐C)·poly d(G‐C) are metastable and that the actual transition is B ⇌ (A ⇌ A2) ⇌ Z‐DNA.
Prostaglandin endoperoxide synthase contains an EGF‐like domain
Authors: Toh Hiroyuki
Published: July 2002

Prostaglandin endoperoxide synthase was subjected to the computer‐assisted homology search in the protein primary structure database, in order to investigate the regulation mechanism of the expression of prostaglandin endoperoxide synthase. As a result of that, it turned out that prostaglandin endoperoxide synthase shares sequence homology with epidermal growth factor (EGF) in the N‐terminal region. The implication of the existence of an EGF‐like domain in prostaglandin endoperoxide synthase is discussed.
Arrestin of bovine photoreceptors reveals strong ATP binding
Authors: Glitscher W. , Rüppel H.
Published: July 2002

Rhodopsin; Arrestin; Transducin; ATP binding; ADP/ATP exchange
Spectroscopic studies of partially reduced forms of Wolinella succinogenes nitrite reductase
Authors: Blackmore R.S. , Gadsby P.M.A. , Greenwood C. , Thomson A.J.
Published: July 2002

Reductive titrations of the dissimilatory hexa‐haem nitrite reductase, Wolinella succinogenes, with methyl viologen semiquinone (MV) and sodium dithionite, have been followed at room temperature by absorption, natural (CD) and magnetic circular dichroism (MCD) spectroscopies and at liquid helium temperature by electron paramagnetic resonance (EPR) and MCD spectroscopies. The nature of the reduced enzyme depends on the reductant employed. At room temperature a single high‐spin ferous haem, observed by MCD after reduction with MV, is absent from dithionite reduced samples. It is suggested that a product of dithionite oxidation becomes bound with high affinity to the reduced state of the enzyme causing the ferrous haem to become low‐spin. The site occupied is likely to be the substrate binding haem. The course of the titration with MV at room temperature shows the reduction of high‐spin ferric to high‐spin ferrous haem. Since the EPR spectrum reveals the presence of an unusual high‐low spin ferric haem pair in the oxidised state we propose that the active site of the enzyme is a novel haem pair consisting of one high (5‐coordinate) and one low‐spin (6 coordinate) haem, magnetically coupled and possibly bridged by a histidinate ligand.
The reaction specificities of the pea and a cyanobacterial thylakoid processing peptidase are similar but not identical
Authors: Wallace T.P. , Robinson C. , Howe C.J.
Published: July 2002

The thylakoid processing peptidase from the cyanobacterium Phormidium laminosum has been extracted from thylakoid membranes by solubilization with Triton X‐100. Its reaction specificity has been compared with the analogous pea peptidase by processing in vitro of radiolabelled wheat and P. laminosum thylakoid lumenal precursor polypeptides. The cyanobacterial polypeptide is processed to the mature size through an intermediate by the P. laminosum peptidase, but to a polypeptide that has a slightly greater apparent molecular weight than the intermediate by the pea peptidase. Both peptidases correctly process the wheat polypeptide. This suggests that the reaction specificities of the two peptidases are similar, but not identical.
Adenylyl cyclase activity of the fission yeast Schizosaccharomyces pombe is not regulated by guanyl nucleotides
Authors: Engelberg David , Poradosu Enrique , Simchen Giora , Levitzki Alexander
Published: July 2002

The adenylyl cyclase activity of the fission yeast Schizosaccharomyces pombe is localized to the plasma membrane of the cell. The enzyme utilizes Mn2+/ATP as substrate and free Mn2+ ions as an effector. Unlike the baker yeast Saccharomyces cerevisiae, S. pombe adenylyl cyclase does not utilize Mg2+/ATP as substrate and the activity is not stimulated by guanyl nucleotides. The optimal pH for the S. pombe adenylyl cyclase activity is 6.0. The activity dependence on ATP is cooperative with a Hill coefficient of 1.68 ± 0.14.