bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Rhizobium Inoculation and Phosphate Rock Fertilizer Application on Growth and Yield Components of Green gram (Vigna radiata) in Tharaka-Nithi County, Kenya
Authors: Mbaka F. K. , Oloo-abucheli G. O. , Njoroge P. K. , Ndukhu H. O.
Published: March 2021

Green gram is an important drought tolerant grain legume crop in Kenya. In Tharaka Nithi County green gram is as a major source of food security. Hence, there is need for a cheap and sustainable system of agricultural production is needed to increase its production. The legume/Rhizobium symbiosis in combination with phosphate rock offers a natural system for improving green gram nitrogen fixation. Therefore, this study was aimed at determining the effect of Rhizobium and phosphate rock fertilizer application on growth and yield attributes of N26 and KS20 varieties. The study was carried out at Chuka University Horticultural Research Farm for two seasons, November 2019 to January 2020 and February to April 2020. Factorial experiment of 2x2x2 was laid out in a Randomized Complete Block Design (RCBD). There were three factors, variety (N26 and KS20), phosphate rock (0 and 30 kg P ha-1) and Rhizobium MEA 716 (0 and 100 g ha-1). The experiment contained eight treatments which were replicated three times. The data was collected fortnightly on four randomly selected plants on parameters such as plant height, number of leaves, branches, pods, total dry biomass, shoot and root dry weight and grain yield. These data was analysed using Statistical Analysis Software (SAS). Significant means are separated using Least Significant Difference (LSD) at probability level of 5%. Results for both seasons indicated that combined application of Rhizobium MEA 716 Rhizobium 100 g ha-1 and phosphate rock 30 Kg ha-1 phosphate under variety  in treatment (R1P1V2) showed significantly (P<0.05) higher  plant height (76.07 cm), number of branches (14.08 plant-1), shoot dry biomass (52.01 g plant-1), root dry biomass (7.60 g plant-1), total dry biomass (146.4 g plant-1), number of pods (84 plant-1) and yield (2158 kg ha-1) compared to variety N26 in treatment (R1P1V1).  Therefore, combination of Rhizobium MEA 716 100 g ha-1 and phosphate rock 30 Kg ha-1 under variety KS20 led to improved growth attributes equally yield components of KS20 variety over N26. From these findings, application of Rhizobium MEA716  at 100 g ha-1, and 30 Kg ha -1  phosphate rock under variety KS20 was recommended for improved and a sustainable green gram production in  the study area.
Effects of the Digestate Produced by the Bio-Digester EB.06019.LHT-MWINDA on the pH of Kimwenza-Mission Soil and the Growth of Amaranthus cruentus
Authors: Mukuna Balthazar K. , Monga Justine M. , Wembi Gaston L. , Ipassou Alphonsine , Lokadi Pierre L.
Published: March 2021

The evaluation of the effects of the digestate produced by the reactor EB.06019.LHT-MWINDA on the pH of Kimwenza soil and the growth of Amaranthus cruentus was conducted during the dry season (June-July 2019). Two treatments were used for the experiment: NPK (T1) and digestate (T2). The untreated soil was taken as a negative control(T0). The results obtained show that the digestate has a more neutralizing effect on the acidity of the Kimwenza-mission soil than the mineral fertilizer: the pH increased from 4.40 ± 0.33 to 9.28 ± 0.45 for T2 versus 5.19 ± 0.59 to 7.71 ± 0.29 for T1. The plants treated with T2 gave leaves with relatively more weight (1.8 ± 0.5g) than those obtained with T1 (1.06 ± 0.87g). It was observed that plants treated with digestate were taller (10,4 ±1,1m) than those with NPK (9,45 ±1,13m). The average number of leaves obtained from plants was 7.06 ; 6.36 and 5.97 respectively for T2, T1 and T0. These results are an indication that the digestate produced by the reactor EB.06019.LHT-MWINDA could be used for the amendment of the acidic soil of Kimwenza-Mission and therefore contribute to reducing significantly the use of synthetic agro-chemicals, hence decreasing residual environmental and human health hazards.
Response of Growth, Yield and Essential Oil of Geranium Plants to Surface Irrigation and Humic Acid Treatments
Authors: Hammam K. A. , AwadAlla Salwa S. S. , Noreldin Tahany
Published: March 2021

Water is among the most important factors affected growth, yield and quality of medicinal and aromatic plants since its deficiency may cause serious growth harms and yield losses. Egypt suffers from a scarcity of water, so each drop should be preserved. Therefore, the objective of the present study was to determine the suitable irrigation treatment (120, 100 and 80% ETo (evapotranspiration) and humic acid amounts (control), 1.0, 1.5 and 2.0 cm/L) that attain the highest growth, yield and essential oil of geranium (Pelargonium graveolens L. Herit Aiton) under surface irrigation in clay soil at El Kanater El Khairiya. Results showed that humic acid alleviated the deteriorative effect of water deficiency, where plants irrigated with 120% ETo and treated with 2.0 cm/L humic acid improved the growth characters in terms of plant height, number of branches, fresh, dry weights and volatile oil yield. While, the highest volatile oil percentage and proline content were recorded at 80% ETo with humic acid at 2.0 cm/L treatment during the two growing seasons. Results also showed that the applied irrigation water under 120% ETo treatment was 7192 m3/fed averaged over the two growing seasons attained the highest yield. The highest values of water use efficiency and water productivity were 14.1 and 10.0 averaged over the two growing seasons attained under 80% ETo and application of 2.0 cm/L humic acid. Thus, it can be concluded that the required irrigation water for geranium is under 120% ETo. However, under water deficiency, 80% ETo and 2.0 cm/L humic acid could be applied, which increase geranium yield by 24%, compared to the 120% ETo treatment averaged over the two growing seasons.
Morphological and Physiological Screening of Aerial Yam (Dioscorea bulbifera L.) for Sodium Chloride Tolerance
Authors: Kalu S. E. , Osuagwu A. N. , Ekpo I. A. , Okonko L. E. , Ubi G. M.
Published: March 2021

Aerial yam (Dioscorea bulbifera L.) is an indigenous, edible and energy-giving crop used for herbal remedy for some common ailments like diabetes, dysentery, cholera and conjunctivitis. It is fast-growing and can adapt to different soil types and habitat conditions, therefore seen as having the potential of tolerating salt stress conditions in this area of climate change. This study, therefore, sought to determine the tolerance of D. bulbifera to salt stress conditions through morphological and physiological studies. Bulbils of D.bulbiferaof two distinguished shapes were sourced from local farmers in Abia State, AkwaIbom State and Cross River State of the Niger- Delta region of Nigeria, and established in Biological Sciences Research Farm, University of Calabar, Calabar, to have the various lines for the experiment. Randomized Complete Block Design (RCBD) with three replications was used for the study. At four weeks after sprouting, the plants were treated with 250ml of different concentrations of sodium chloride (0, 100, 200 and 300mM) twice a week for six weeks. Morphological data of leaf color, number of leaves/plant, root length, leaf length, petiole length, leaf area, vine length and number of bulbils were measured weekly during the treatment period while physiological data of Chlorophyll-a and chlorophyll- b concentrations, peroxidase and glucose-6-phosphate dehydrogenase activities were analyzed two weeks after the completion of the treatment. Results revealed that sodium chloride reduced the vine length, number of leaves, number of bulbils, chlorophyll-a and chlorophyll-b concentrations of the plant, and caused an increase in the root length, peroxidase and glucose-6- phosphate dehydrogenase activities. Although sodium chloride reduced the growth of the D.bulbifera, all the lines were able to produce bulbils at a salt concentration of 0.00mM to 200mM. Therefore, this plantcould be regarded as a moderate salt tolerant plant. Significant differences in growth and yield were found between the lines (P<0.05). Bulbils with round shape tended to show more growth than the spindle shape.
Assessment of Fish Consumption Patterns amongst Students in Kwara State Nigeria
Authors: Abiodun Adeoso , Abiodun Adebayo-Oyetoro
Published: March 2021

Fish is a nutrient dense food of animal origin commonly consumed across lifecycle. Different species are found across continents based on many factors with varying benefits of which health is key.  The nutrition benefits of fish are not fully understood among youths as many consume other sources of protein for many reasons due to lack of information. The diverse reasons for consuming other sources of protein such as meat, eggs, poultry etc. need to be investigated so as to increase nutrition education among youths. This study was designed to determine the fish consumption levels among undergraduates, reasons for its consumption, and reasons for non-consumption. A descriptive cross-sectional study was carried out among one hundred and fifty(150) students from Kwara State Polytechnic and one hundred and fifty-two students (152) of the University of Ilorin with a total of three hundred and two (302) undergraduate students. Respondents were randomly selected in each institution. Self-administered structured questionnaires containing both persona and dietary information were filled. Results showed that about 92.4% (280) respondents consume fish in any form; 57.2% (174) preferred frying to boiling; 53.5% (162) preferred mackerel locally called Titus in Nigeria to any other species. Fish consumption when cross matched with educational qualification indicates increase in consumption with education qualification. Respondents with National Diploma qualification (51.8%) consumed fish more than once in a week, this could be as a result of their environment or financial status compared with others. Nutrition education on fish consumption especially amongst youths should increase to enable them obtain essential nutrients such as iodine, omega- 3 fatty acid necessary for memory improvement. Hygiene and display pattern by retailers should also improve to make purchase and consumption of fish more appealing for the youths. Government agencies such as the Ministry of Health should educate marketers on safer ways of handling fish from farm to retail. Members of the public should also be sensitized on consequences of consuming unwholesome foods particularly with respect to risk assessment.
Processing of Wild Sunflower with Different Moisture Contents into Solid Bio Fuel
Authors: Dummapi Fabie T. , Liniasan Jacqueline I. , Valentin Marvin T. , Onalan Milagros B. , Dumalhin Leonardo D. , Galad Marlon N. , Ciolkosz Daniel , Jasinskas Algirdas , Kelly Eva J.
Published: March 2021

Wild sunflower with moisture contents of 16%, 12% and 8% was densified without the addition of binding agent. The physical properties of the formed briquettes such as mass, dimensions, volume, density and shattering resistance were evaluated. Thermal properties like ignition time, burning time, ash content, and thermal fuel efficiency by means of boiling test were also evaluated.

Wild Sunflower stems were gathered and shredded using locally fabricated biomass shredder available at the Research Office of Benguet State University, and were processed into the desired size and moisture contents. Right after the briquetting operation, the physical properties of the briquette were measured and then stored in a zip bag for 24 hours. After the storage, same measurement was conducted.

Results show that the influence of moisture contents on the average mass, dimension, shattering resistance, volume and density was statistically insignificant. The wild sunflower with moisture content of 16% had the highest shattering resistance of 88.85%. Furthermore, the influence of moisture content on the thermal properties like ignition time, burning time and ash content are statistically insignificant. Among the moisture contents, the fastest ignition time of 43.75 sec with longest burning time was recorded under 12%. Ash content was also lowest at 12%.
Response Surface Optimization of Corn Husk Fiber Mercerization Using NaOH
Authors: Mmelikam Chukwuemeka Julius , Tagbo Nwabanne Joseph , Ifeanyi Ugonabo Victor
Published: March 2021

The optimum mercerization parameters for treatment of corn husk using NaOH were analyzed by response surface methodology (RSM). The surface morphology and chemical structures of the raw and NaOH-treated fibers were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) to validate the RSM results. The optimum chemical characteristics of corn husk treated with NaOH obtained when 100g of corn husk biomass was mercerized in 2.5Mol/dm3 NaOH for 8 days were: cellulose -70.51%, hemicellulose -8.99%, lignin -6.54, weight loss – 92.27%, ash content -10.11% and extractive -3.78%. The model summary statistics showed that quadratic model best fitted the optimization analysis. The ANOVA results showed that weight loss, hemicellulose, cellulose and lignin contents of corn husk biomass were affected by retting time, retting concentration and weight of biomass. Cellulose content of corn husk was observed to increase with increment in retting time and retting concentration while the reverse is the case for hemicellulose and lignin contents. The NaOH-treated corn husk has higher cellulose content than the untreated corn husk biomass while the reverse is the case for hemicellulose and lignin. SEM images showed that untreated corn husk biomass has irregular cross-section, non-uniform surface and some impurities while NaOH treated is finely packed together. XRD graphs showed that cellulose is the predominant content of the fiber. The FTIR results also indicated a variation of the peaks of the curves after treatment which favors an increase in the cellulose content.
Effect of Extracted Microcrystalline Cellulose from Dracaenea arborea Stem on Aceclophenac Tablet Formulation
Authors: Ordu J. I. , Udenze I. E.
Published: March 2021

Micro crystalline cellulose (MCC) is a major derivative from the bio composite of natural materials such as D. arborea plant stem. It could be useful as a secondary binder and disintegrant in tablet formulation especially following direct compression technique anticipating it to provide high level of disintegration at low use level and utilizing dual mechanisms of wicking and swelling. Tablets of aceclofenac a BCS class II and non steroidal anti inflammatory drug (NSAID) which potently inhibits the cyclo oxygenase enzyme (COX-2) involved in prostaglandin synthesis was formulated by direct compression using MCC from D. arborea stem. Qualitative assessment of the plant extract was carried out and the presence of cellulose confirmed by the appearance of violet – blue coloration while the physicochemical and physicotechnical properties were comparatively evaluated with reference to avicel and corn starch. Three batches of aceclofenac tablets involving Batch A (D. arborea MCC), Batch B (Corn starch) and Batch C (Corn starch and D. arborea MCC in a 1:1 ratio), were implcated in the formulation. Physicochemical study of the MCC reveals a pH of 7.8, mean swelling index 1.14±0.05 ml and hydration capacity of 3.60±0.15 g while the pH of corn starch is 3.90 with swelling and hydration capacity at 5.09±0.03 ml and 8.26±0.01 g respectively. Quality control evaluation of resulting tablet was investigated and the wetting time of batch A tablets was 1.50, batch B 2.30 and batch C 1.80 with percentage moisture content (%) of 60.5, 56.56 and 57.8 and disintegration time (minutes) of 0.22±0.07, 0.35±0.051 and 1.60±0.286 respectively. The drug release profile of batch A, reveals an initial burst release within 10 minutes followed by gradual release while batch C had consistent drug release which was maintained although faster than that of batch A after 10 minutes but batch B had the least drug release rate.
Organizational Climate Factors in Job Creativity among Public University Librarians in Anambra State
Authors: Nwangwu Nneka I. , Etodike Chukwuemeka E. , Okeke Helen C. , Nnaebue Collins I.
Published: March 2021

Education is the greatest stimulant for human development and the requisite for socio-economic advancement; the utility of libraries in education especially in tertiary institutions are as important as education itself. In third world countries like Nigeria, there is a great disparity in library utility. This study has therefore envisaged that unless librarians are creative given supportive climate, they may not actualize the potentials of libraries given funding inadequacies.  Thus, a survey study was carried out utilizing correlation design Pearson correlation statistics to establish the perception of librarians about their organizational climate and whether this perception correlates their creativity.  The participants of the study were 89 librarians sampled purposively from University librarians in Anambra State. The questionnaires used for data collection were simplified adaptation of Coveney (2008) and Organizational Climate Questionnaire (OCQ) by Litwin and Stringer (1968). The result indicated that the perception of organizational climate is low among University librarians in Anambra State although the librarians were moderately high on creativity and innovation. Responsibility, reward and support were dimensions of organizational climate which predicted employee creativity whereas organizational identity though impact employees’ creativity but the impact were not of significance proportion. The finding implies that favorable climate to employees helps to stimulate their creative potentials. It is recommended that stakeholder should improve the working climate in University libraries in order to motivate to employees to perform at the highest level bringing their creativity into the organizational dynamics.
The numerical solution of stiff differential equations
Authors: Cooper G.J.
Published: July 2002

The separate problem of stability and accuracy in numerical methods of approximating the solution of systems of non‐linear equations is then treated. Stress is laid on the consistently unsatisfactory results given by explicit methods for systems containing “stiff” equations, and implicit multistep methods are particularly recommended for this class of problem, which is likely to include many biochemical model systems. Finally, an iteration procedure likely to give convergence both in multistep methods and in the steady‐state approach is recommended, and areas in which improvement in methods is likely to occur are outlined.
Electrochemically driven respiration in mitochondria and Paracoccus denitrificans
Authors: Coleman J.O.D. , Hill H.A.O. , Walton N.J. , Whatley F.R.
Published: July 2002

By exploiting the rapid, direct electrochemistry of horse heart cytochomre c at a modified gold electrode it has been possible to couple the electrode reaction with respiration in rat liver mitochondria and in photoplasts of Paracoccus denitrificans, but not in protoplasts from E. coli. Oxidation of endogenous and exogenous sources of reducing equivalents via cytochrome c is also observed.
Characterization of acid and alkaline phosphatase activity in preparations of tubulin and microtubule‐associated proteins
Authors: Prus Karen , Wallin Margareta
Published: July 2002

Acid and alkaline phosphatase activity, determined by the hydrolysis of p‐nitrophenyl phosphate, was found in preparation of microtubules purified from bovine brain by temperature‐dependent assembly—disassembly and ion‐exchange chromatography. Phosphocellulose‐purified tubulin contained an associated acid phosphatase activity, stimulated by Mg2+ and Zn2+. Alkaline phosphatase activity with a pH optimum of 10.4 was measured in a fraction of microtubule‐associated proteins (MAPs). Kinetics and the effects of sodium fluoride, sodium tartrate, sulfhydryl‐blocking agents, EDTA and Zn2+ are reported.
Z‐DNA and other non‐B‐DNA structures are reversed to B‐DNA by interaction with netropsin
Authors: Zimmer Christoph , Marck Christian , Guschlbauer Wilhelm
Published: July 2002

The interaction between the B‐form specific ligands netropsin (Nt) and distamycin‐3 (Dst‐3) and DNA duplexes has been studied under conditions of salt concentration and low water activity that modify the polymer conformation into a non‐B DNA form, putatively a Z‐like form. Three polymers with strict alternating purine‐pyrimidine sequences and GC content from 100—0% have been tested: poly(dG—dC)·poly(dG—dC), poly(dA—dC)·poly(dG—dT) and poly(dA—dT)·poly(dA—dT). The titrations by Nt and Dst‐3 were followed by circular dichroism. Although specific binding of Nt to the Z‐form of poly(dG—dC)·poly(dG—dC) does not occur, Nt reverses this Z structure to the B‐type conformation; Dst‐3 is, however, totally inefficient. The presumed non‐B or Z‐like structure of poly(dA—dC)·poly(dG—dT) is reversed to the B‐form upon interaction with Nt; Dst‐3 also induces this reversal but at higher ligand ratios. The modified B‐structure of poly(dA—dT)·poly(dA—dT) in low water activity is efficiently reversed to the B‐form by interaction with both Nt and Dst‐3.
Different adhesion inhibiting activities of antisera against plasma membranes of liver and Morris hepatoma 7777
Authors: Neumeier Reinhard , Dethlefs Ulrike , Reutter Werner
Published: July 2002

Cell‐substratum adhesion of rat hepatocytes was inhibited by antisera raised against plasma membranes of liver (anti‐liver antiserum) and Morris hepatoma 7777 (anti‐hepatoma antiserum). Similar concentrations of both antisera inhibited adhesion on collagen. Anti‐liver antiserum also inhibited the adhesion of hepatocytes on plastic, whereas anti‐hepatoma antiserum was only able to inhibit the adhesion on collagen completely. These results suggest the existence of at least two different adhesion‐involved molecules. Cells adhere to plastic by means of both molecules, whereas adhesion on collagen is mediated by only one of them. The results further suggest that hepatoma cells lost the molecule involved in adhesion on plastic.
Lectins facilitate calcium‐induced fusion of phospholipid vesicles containing glycosphingolipids
Authors: Düzgünes Nejat , Hoekstra Dick , Hong Keeking , Papahadjopoulos Demetrios
Published: July 2002

Ca2+‐induced fusion of phospholipid vesicles containing globoside (GL‐4) or disialoganglioside (GDla) is several‐fold slower than the fusion of the pure phospholipid vesicles. Lectins specific for these glycosphingolipids, soybean agglutinin and wheat germ agglutinin, respectively, enhance the rate of fusion when added to the vesicle suspension before the introduction of Ca2+. The enhancement depends on the lectin concentration and the time of preincubation with the lectin. We propose that lectins facilitate membrane fusion by inducing intermembrane contact, which is the first step in the overall process of membrane fusion, or by laterally phase separating the inhibitory glycolipids.
Overlapping reading frames in Oenothera mitochondria
Authors: Hiesel Rudolf , Brennicke Axel
Published: July 2002

An open reading frame (ORF) preceding the cytochrome oxidase subunit II (CO II) gene in Oenothera mitochondria has four nucleotides in common with this gene. The last two nucleotides of the CO II initiation codon ATG are the first two nucleotides of the TGA termination codon in the upstream ORF. Both reading frames are cotranscribed in a bicistronic mRNA species of 1250 nucleotides in length in Oenothera. The open reading frame codes for a protein of 58 amino acids with structural homology to the ATPase subunit 8 genes in fungal and mammalian mitochondria. Using coding space optimally though overlapping genes appears to be without economical reason considering the large size of higher plant mitochondrial genomes.
Resonance Raman spectroscopy and enhanced photoreducibility for the 420 nm pulsed form of cytochrome oxidase
Authors: Copeland Robert A. , Chance Ali Naquit Britton , Spiro Thomas G.
Published: July 2002

Resonance Raman (RR) spectra, with 413.1 nm Kr+ laser excitation, are reported for cytochrome oxidase in resting, reduced, and 428 nm (oxygenated) forms, and for the first time, in the 420 nm (pulsed) forms [(1984) J. Biol. Chem. 259, 2073‐2076]. The differences between the resting, 420 nm, and 428 nm forms' RR spectra are small. All these forms contain FeIII only, as indicated by single v4 bands at ~1371 cm−1, and the reoxidized forms show partial conversion from high‐ to intermediate‐ or low‐spin heme a
3 (intensity shift from 1575 to 1588 cm−1 for v2). The 420 nm form differs strikingly from both the 428 nm and resting forms, however, in being much more readily photoreduced by the laser illumination. This property is linked to the protein conformational change believed to be responsible for the greater accessibility to exogenous ligands of the heme a
3 in the 420 nm form.
Ribosome ‐ SRP ‐ signal sequence interactions
Authors: von Heijne Gunnar
Published: July 2002

The role of the signal sequence in protein export is reviewed, and some difficulties inherent in the conventional picture of how it interacts with other components of the export machinery are pointed out. An alternative model is suggested, which seems to account better for some of the critical experimental findings made so far.
Liver carnitine metabolism after partial hepatectomy in the rat
Authors: Schofield Paul S. , French Timothy J. , Goode Anthony W. , Sugden Mary C.
Published: July 2002

This study examined the effects of partial hepatectony on hepatic carnitine and acylcarnitine concentrations in fed or 24 h‐starved partially hepatectonized (PH) or sham‐operated (SO) rats at 1 or 4 days after surgery. The ratio of free to esterified carnitine was low in fed PH rats at day 1 : the low ratio was increased to the SO value when mitochondrial fat oxidation was inhibited by 2‐tetradecylglycidate. Starvation (24 h) increased plasma [non‐esterified fatty acid] in PH or SO rats, the increases being greater at day 1 than at day 4. Hepatic [long‐chain acylcarnitine] were also increased. These latter increases were a consequence of increased mitochondrial fat oxidation since they were not observed in PH or SO rats treated with 2‐tetradecylglycidate. Whereas the starvation‐induced increase in long‐chain acylcarnitine was associated with increased [ketone body] in livers of SO rats at both day 1 and day 4 after surgery, [ketone body] was inappropriately low for the steady‐state long‐chain [acylcarnitine] in livers of PH rats at the first post‐operative day. This was not a consequence of a decrease in [total carnitine] in the liver. The results are discussed with reference to the role of the liver in determining the relative proportions of the fat fuels available for extrahepatic tissues and the effects of liver cell proliferation on hepatic triacylclycerol metabolism.
Modulation of gastric H+, K+‐transporting ATPase function by sodium
Authors: Ray Tushar K. , Nandi Joytirmoy
Published: July 2002

Gastric H+, K+‐ATPase activity is not affected by Na+ at pH 7.0 but is significantly stimulated by Na+ at pH 8.5. For the stimulation at the latter pH, the presence of both Na+ and K+ were essential. Contrary the H+, K+‐ATPase, the associated K+‐pNPPase was inhibited by Na+ at both pH values. Sodium competes with K+ for the K+‐pNPPase reaction. Also, unlike the H+, K+‐ATPase activity the ATPase‐mediated transport of H+ within the gastric microsomal vesicles was inhibited by Na+. For the latter event only the extravesicular and not the intravesicular Na+ was effective. The data suggest that the K+‐pNPPase activity does not represent the phosphatase step of the H+, K+‐ATPase reaction. In addition, the observed inhibition of vesicular H+ uptake by Na+ appears to be due to the displacement by Na+ of a cytosolic (extravesicular) H+ site responsible for the vectorial translocation of H+
Saturable [D‐Ala2, D‐Leu5]‐enkephalin transport into cholinergic synaptic vesicles
Authors: Day Nicola C. , Wien Daniela , Michaelson Daniel M.
Published: July 2002

Enkephalin uptake
Synaptic vesicle
Acetylcholine Torpedo
Fructose 2,6‐bisphosphate and the control of glycolysis in bovine spermatozoa
Authors: Philippe Benoît , Rousseau Guy G. , Hue Louis
Published: July 2002

Epididymal bovine sperm contain fructose‐1,6‐bisphosphatase activity which is inhibited by AMP and by fructose 2,6‐bisphosphate. Sperm phosphofructokinase displays kinetic characteristics that are typical of the F‐type and it is stimulated by fructose 2,6‐bisphosphate. The concentration of sperm fructose 2,6‐bisphosphate remained unaffected at 1–2 μM when the glycolytic rate was either increased by glucose, caffeine or antimycin, or decreased by α‐chlorohydrin or 6‐chloro‐6‐deoxyglucose.
N‐terminal sequence homologies in interstitial retinol‐binding proteins from 10 vertebrate species
Authors: Fong Shao-Ling , Cook Richard G. , Alvarez Richard A. , Liou Gregory I. , Landers Robert A. , Bridges C.D.B.
Published: July 2002

We report here the first comprehensive comparative NH2‐terminal sequence studies of interstitial retinolbinding protein (IRBPs) from nine mammals (including cattle) and one amphibian. This study has revealed that in many species the N‐terminus of IRBP includes a 3–6 amino acid extension. IRBP possessing this leader sequence is sometimes mixed with IRBP from which this sequence has been excised.
The formation of inositol phosphate derivatives by isolated membranes from Acer pseudoplatanus is stimulated by guanine nucleotides
Authors: Dillenschneider M. , Hetherington A. , Graziana A. , Alibert G. , Berta P. , Haiech J. , Ranjeva R.
Published: July 2002

Membranes isolated from Acer pseudoplatanus cell suspension cultures that were prelabelled with [3H]inositol are able to release different water‐soluble phosphoinositol derivatives in a time‐dependent manner. Addition of adenine, cytidine or uridine nucleotide has no effects on the process. In contrast, guanine nucleotide triphosphates were stimulatory in a dose‐dependent manner. The non‐hydrolyzable derivative guanosine 5'‐[γ‐thio]triphosphate was the most effective activator while guanosine 5'[β‐thio]diphosphate inhibited the action of GTP. It is suggested that GTP‐binding proteins exist in the Acer membrane and play a regulatory role in the formation of potentially important second messengers.
Calmodulin may decrease cell surface sialic acid and be involved in the expression of fibronectin during liver regeneration
Authors: Coll Mia J. , Serratosa Joan , Bachs Oriol , Gahmberg Carl G. , Enrich Carlos
Published: July 2002

The decrease of sialic acid in plasma membrane glycoproteins and the expression of cell surface fibronectin were studied during the pre‐replicative phase of liver regeneration. The aim of this study was to correlate these cell‐surface events to the intracellular surge of calmodulin observed a few hours after partial hepatectomy. The fact that calmodulin decreased the specific activity of UDP‐N‐acetyl‐D‐glucosamine 2'‐epimerase, a key regulatory enzyme in the biosynthesis of glycoprotein sialic acids, and that trifluoperazine prevented the desialylation indicates that the membrane desialylation is a calmodulin‐dependent process. On the other hand, Western blotting using anti‐rat fibronectin antibody in trifluoperazine‐treated animals suggests that calmodulin may also be involved in the surface expression of fibronectin in regenerating hepatocytes.
Common domain structure of Ca2+ and lipid‐binding proteins
Authors: Geisow Michael J.
Published: July 2002

Lipocortin
Ca2+ binding
Endonexin
Calelectrin
Phospholipase A2

Membrane binding
Rat liver cytosol oxysterol‐binding protein
Authors: Beseme F. , Astruc M.E. , Defay R. , de Paulet A.Crastes
Published: July 2002

A cytosol protein that specifically binds cholesterol derivatives oxygenated on the side chain has been demonstrated in rat liver and transformed HTC cells. This protein, of which the sedimentation coefficient is about 8 S, was saturable and showed a high binding affinity (K
d about 5 × 10−9M) for 25‐hydroxycholesterol. Its molecular mass is about 160 kDa. The physicochemical characteristics of this protein were identical whether the model was normal or transformed. This oxysterol‐binding protein differs from the well‐known sterol carrier proteins.
Basement membrane collagen ‐ evidence for a novel molecular packing
Authors: Barnard Kay , Gathercole L.J. , Bailey A.J.
Published: July 2002

Type IV collagen is the major structural protein of basement membranes but very little is known about its molecular organisation in vivo. We have used X‐ray diffraction of a thick basement membrane, bovine lens capsule, to provide information. Under constant load, lens capsule gave a collagen diffraction pattern of a similar quality to unstretched rat rail tendon. In addition there were clear meridional reflections which indexed as orders of 10 nm, and equatorial reflections at 2.1 and 3.8 nm. These results suggest the ordering of type IV collagen molecules in fibrils, with a 10 nm periodicity along the length of the fibrils.
Anoxic brain function: Molecular mechanisms of metabolic depression
Authors: Brooks S.P.J. , Storey K.B.
Published: July 2002

An examination of the kinetic parameters of phosphofructokinase, pyruvate kinase and glycogen phosphorylase, and the cellular concentration of fructose 2,6‐bisphosphate during anoxia in the turtle Pseudemys scripta showed that the total activity of glycogen phosphorylase, and the phosphofructokinase inhibition constants for citrate and ATP were decreased in anoxic turtle brain. These results suggest that the ability of turtle brain to survive extended periods of anoxia is the result of metabolic rate depression regulated, at the molecular level, by enzyme inactivation through anoxia‐induced covalent modification.
FTIR studies on crystals of photosynthetic reaction centers
Authors: Gerwert Klaus , Hess Benno , Michel Hartmut , Buchanan Susan
Published: July 2002

It is shown that high‐quality light‐induced FTIR‐difference spectra can be obtained from reaction center crystals of Rhodopsendomonas viridis. Difference spectra between the ground state, PQ, and a light‐activated state, P+Q−, have been recorded. The difference spectra are in good agreement with those reported previously for reaction centers reconstituted into lipid vesicles [(1985) FEBS Lett. 187, 227–232]. This good correspondence indicates that in both sample preparations the same intramolecular processes take place during this transition. In addition to measurements of absorbance changes in the visible spectral region, which indicate reactions of the chromophores and their microenvironments, those in the infrared spectral region also show that the protein side groups and backbone undergo the same light‐induced changes in the crystals. It is observed that, besides the porphyrin ring system, the C9 = O keto and ester groups of, most likely, the primary donor, undergo light‐induced changes in charge distribution during oxidation of the primary donor. Large conformational changes of the protein backbone can be excluded for the observed transition.
Binding of ras p21 to bands 4.2 and 6 of human erythrocyte membranes
Authors: Tanimoto Tetsuji , Hoshijima Masahiko , Kawata Masahito , Yamamoto Katsuhiko , Ohmori Toshihiko , Shiku Hiroshi , Nakano Hirofumi , Takai Yoshimi
Published: July 2002

The direct binding protein(s) of ras p21 was (were) investigated in inside‐out vesicles of human erythrocyte ghosts using the pure v‐Kirsten (Ki)‐ras p21 synthesized in E. coli. The bound ras p21 was detected immunochemicallly using an anti‐v‐Ki‐ras p21 monoclonal antibody. ras p21 bound to vesicles. Prior digestion of the vesicles with trypsin reduced this binding significantly. When ras p21 was laid over vesicle proteins immobilized on a nitrocellulose sheet by transfer from the gel of SDS‐polyacrylamide gel electrophoresis, ras p21 bound to bands 4.2 and 6. ras p21 binding to these proteins was reduced by prior incubation of ras p21 with the purified band 4.2 or 6 protein. These results indicate that v‐Ki‐ras p21 can bind directly to bands 4.2 and 6 of human erythrocyte membranes as far as tested in an in vitro cell‐free system.
Testing topological models for the membrane penetration of the fusion peptide of influenza virus hemagglutinin
Authors: Brunner Josef
Published: July 2002

Low pH‐induced binding of the bromelain‐solubilized form of influenza virus hemagglutinin (BHA) to membranes occurs through the fusion peptide. From asymmetric hydrophobic photolabeling of membranes, evidence was obtained that this peptide penetrates only one leaflet of the bilayer. The asymmetrical labeling was achieved by employing a photoreactive analogue of a fatty acid whose transbilayer distribution can be manipulated by a membrane proton gradient.
Functional characteristics of calcitonin gene‐related peptide receptors in human Ewing's sarcoma WE‐68 cells
Authors: van Valen F. , Keck E. , Jürgens H.
Published: July 2002

Calcitonin gene‐related peptide; Calcitonin; cyclic AMP; (Human; Ewing's sarcoma cell)
An activating combination of CD2 antibodies stimulates tyrosine phosphorylation in a T lymphocyte cell line
Authors: Casnellie John E. , Thom Rebecca E.
Published: July 2002

The activating combination of CD2 antibodies Leu‐5b plus 9.1 stimulates tyrosine phosphorylation in the human T cell line Jurkat. The tyrosine phosphorylation has the same molecular weight pattern as that seen when cells are stimulated on the CD3 receptor with OKT3 antibodies. These data provide evidence that signal transduction by the CD2 receptor is coupled to an increase in tyrosine phosphorylation that is similar to that coupled to the CD3 receptor.
Multiple polyadenylation sites are active in the α 1‐tubulin gene from Zea mays
Authors: Montoliu Lluis , Rigau Joan , Puigdoménech Pére
Published: July 2002

Two cDNA clones (MR2 and MR29) encoding the same α‐tubulin isotype (α1) have been identified and characterized from maize roots. The sequence of these two cDNA clones is identical to a previously described cDNA clone (MR19) except in the location of their polyadenylation site. The sequence of the cDNA and its homologous genomic clone (MG) shows two putative polyadenylation signals which could direct the variable 3′ processing of the observed transcripts. Endonuclease Sl protection analysis in this 3' flanking region confirms the presence in the α1‐tubulin gene from Zea mays of these two main functional polyadenylation sites and possibly other related ones. The relative accumulation of RNAs bearing the two main polyadenylation sites has been tested by using a RNA‐slot analysis of several tissues of the plant. It appears that a higher proportion of shorter mRNA species is found in actively dividing tissues.
The cholecystokinin gene is abundantly co‐expressed with gastrin‐releasing peptide, enkephalin and neuropeptide Y genes in a clonal human neuroepithelioma cell line
Authors: Verbeeck Marleen A.E. , Burbach J.Peter H.
Published: July 2002

The cholinergic human neuroepithelioma cell line SK‐N‐MCIXC expressed mRNAs for the neuropeptides cholecystokinin (CCK), neuropeptide Y, gastrin‐releasing peptide (GRP) and enkephalin. The CCK transcript of about 800 nt was present at very high levels and CCK‐like peptides immunoreactive to a C‐terminal CCK octapeptide antiserum were present in the cell line and its medium. This clonal neuronal cell line provides a unique model system to identify cis‐ and trans‐acting factors responsible for neuron‐specific expression and regulation of the CCK gene. Further‐more, the pluripotent properties of the undifierentiated cell line may open studies on neuronal differentiation at the level of co‐expression of neuropeptides and transmitters.
Site directed mutagenesis of subunit 8 of yeast mitochondrial ATP synthase
Authors: Nero Debra , Ekkel Sue M. , Wang Lin-Fa , Grasso David G. , Nagley Phillip
Published: July 2002

The function of the positively charged C‐terminal region of mitochondrially encoded subunit 8 of yeast mitochondrial ATP synthase was investigated using derivatives truncated at each of the 3 positively charged residues (Arg37, Arg42 and Lys47). Each construct, allotopically expressed in the nucleus, was tested for its ability to import and assemble functionally into ATP synthase in yeast cells unable to synthesize mitochondrial subunit 8. The efficiency of import of each construct into isolated wild‐type yeast mitochondria was also determined. One construct truncated at the penultimate residue of subunit 8 (Lys47) functions in vivo and shows efficient import in vitro. Thus subunit 8 can function with only two positively charged residues. The remainder of the subunit 8 variants failed to rescue in vivo. Since they all show greatly reduced or undetectable import in vitro, presumably because of the increased hydrophobic character of the subunit 8 moiety in the chimaeric precursors, the status of these variants as regards assembly and function is not clear.
Sialylated carbohydrate chains of recombinant human glycoproteins expressed in Chinese hamster ovary cells contain traces of N‐glycolylneuraminic acid
Authors: Hokke Cornelis H. , Bergwerff Aldert A. , van Dedem Gijs W.K. , van Oostrum Jan , Kamerling Johannis P. , Vliegenthart Johannis F.G.
Published: July 2002

HPLC analysis of sialic acid released from recombinant variants of human tissue plasminogen activator, human chimeric plasminogen activator, human erythropoietin, and human follitropin, expressed in Chinese hamster ovary cells, demonstrates for each glycoprotein the presence of N‐acetylneuraminic and N‐glycolylneuraminic acid in a ratio of 97:3. Structural analysis by 500 MHz1H‐NMR spectroscopy, of the enzymatically released N‐linked carbohydrate chains of chimeric plasminogen activator and of erythropoietin, showed that α2‐3 linked N‐glycolylneuraminic acid can occur in different N‐acetyllactosamine type antennary structures.
Absence of insulinotropic glucagon‐like peptide‐I(7–37) receptors on isolated rat liver hepatocytes
Authors: Blackmore Peter F. , Mojsov Svetlana , Exton John H. , Habener Joel F.
Published: July 2002

The effects of glucagon and the glucagon‐like peptide GLP‐I(7–37) were compared in rat liver hepatocytes. Glucagon elevated cAMP, elevated intracellular free calcium ([Ca2+]1), activated phosphorylase and stimulated gluconeogenesis, whereas GLP‐I(7–37) was without effect on any of these parameters. GLP‐I(7–37) did not block any of the actions of glucagon. The glucagon analog, des His1[Glu9] glucagon, amide, was a partial agonist in liver, but also was an effective antagonist of glucagon actions in liver but not those of GLP‐I(7–37) in islet B cells. It was concluded that in the rat, GLP‐I(7–37) is a potent insulin secretagogue [1] but is without effect on liver.
Structure of the gene encoding the entire mature E1α subunit of human branched‐chain α‐keto acid dehydrogenase complex
Authors: Dariush Nahid , Fisher Charles W. , Cox Rody P. , Chuang David T.
Published: July 2002

We report the isolation of a 22‐kb human genomic clone (G7) that contains 8 exons encoding a partial mitochondrial presequence, the entire mature peptide and the complete 3′ untranslated region of the E1α mRNA of human branched‐chain α‐keto acid dehydrogenase complex. Based on this gene structure, exon 9 contains the Tyr393 → Asn mutation previously identified in the E1α subunit of Mennonite and other maple syrup urine disease (MSUD) patients. Moreover, the homozygous mutation appears to cause skipping of exon 6 in the mutant E1α transcript. The information on the gene structure for the entire mature E1α subunit will facilitate investigations into the molecular basis of MSUD involving this subunit.
Cloning and sequencing of cDNA encoding the putative insect lasma membrane V‐ATPase subunit A
Authors: Gräf Ralph , Novak Frans J.S. , Harvey William R. , Wieczorek Helmut
Published: July 2002

For the first time a cDNA encoding subunit A of an invertebrate V‐ATPase has been sequenced. The cDNA library was prepared from larval midgut of the tobacco hornworm. Manduca sexta, and screened with monoclonal antibodies to the midgut plasma membrane subunit A. From the cDNA sequence the insect subunit A is predicted to consist of 617 amino acids with a relative molecular mass of 68.162. The predicted primary structure is similar to that of the published eukaryotic subunit A proteins (Bos, Daucus, Saccharomyces and Neurospora); it most closely resembles the bovine amino acid sequences with which it has an 83% sequence identity
Time‐resolved fluorometry of purple membrane of Halobacterium halobium O640 and an O‐like red‐shifted intermediate Q
Authors: Ohtani Hiroyuki , Itoh Hiroyasu , Shinmura Toshiki
Published: July 2002

The photocycle of the light‐adapted purple membrane was studied with a time‐resolved fluorometry apparatus: fluorescence of the sample suspension (>660 nm) was pumped with a 633‐nm cw laser and the temporal change induced by a 532‐nm pulsed laser was measured with a photon‐counting‐type transient recorder. The formation and the decay of the O640 intermediate were clearly observed in the pH region between 4.0 and 11.4. A photochemical cycle of N560 was apparently driven in alkaline suspension (pH > 9.3). An O‐like fluorescent intermediate Q appears and decays with time constants of <0.1 ms and 1.7 ± 0.2 ms, respectively.
The polyoxyethylene/polyoxypropylene block co‐polymer Poloxamer‐407 selectively redirects intravenously injected microspheres to sinusoidal endothelial cells of rabbit bone marrow
Authors: Porter Christopher J.H. , Moghimi S.Moein , Illum Lisbeth , Davis Stanley S.
Published: July 2002

Small colloidal particulates (150 nm and below, in diameter) can be redirected specifically to the rabbit bone marrow following intravenous administration by coating their surface with the block co‐polymer poloxamer‐407, a non‐ionic surfactant. The coated colloids are sequestered by the sinusoidal endothelial cells of the bone marrow and are accumulated in dense bodies within these cells. The uptake of poloxamer‐4O7‐coated colloids by marrow eondothelial cells suggests that the steric repulsive barrier, imposed by the polyoxyethylene segment of the polymer, to particle‐cell interaction can apparently be overcome by a specific interaction mechanism(s) with the cell surface. Such a dramatic uptake cannot be achieved with other block co‐polymers of similar structure to poloxamer‐407. The application of the current model for the site‐specific targeting or drug carriers to bone marrow and the prevention of the adherence of metastases of tumours which selectively colonize the bone marrow endothelium is discussed.
Mutational analysis of the role of Glu309 in the sarcoplasmic reticulum Ca2+‐ATPase of frog skeletal muscle
Authors: Vilsen Bente , Andersen Jens Peter
Published: July 2002

Site‐specific mutagenesis was used to analyse the role of the residue, Glu309, in the function of the Ca2+‐ATPase of frog skeletal muscle sarcoplasmic reticulum by substitution with Ala or Lys. At pH 6.0, 100 μM Ca2+ was unable to prevent phosphorylation from Pi, consistent with previous observations on the Ca2+‐ATPase of rabbit fast twitch muscle [Clarke, D.M., Loo, T.W, Inesi, G. and MacLennan, D.H. (1989) Nature 339, 476–478]. At neutral pH, however, micromolar concentrations of Ca2+ were sufficient to inhibit phosphorylation of the Glu309→Lys mutant from inorganic phosphate, suggesting that at least one high‐affinity Ca2+ site was relatively intact in this mutant. The Glu309→Lys mutant was unable to form a phosphoenzyme from ATP at all Ca2+ concentrations studied (up to 12.5 mM), whereas phosphorylation of the Glu309→Ala mutant occurred at 12.5 mM Ca2+, but not at Ca2+ concentrations in the submillimolar range. Kinetic studies demonstrated a reduced rate of dephosphorylation of the E2P intermediate in the Glu309→Lys mutant. A less pronounced stabilization of E2P was observed with the Glu309→Ala mutant, suggesting a possible role of the charge at the position of Glu309 in phosphoenzyme hydrolysis.