bluuebunny/crossref_metadata_2025 huggingface dataset:
The Interdependence of nonstructural proteins (NS1) in development of dengue fever and its effects on the haematological and immune systems in the South east Asian population
Authors: AL-Azzawi Nawfal. N.A. , Mohamed Dzul Azri Noor , Abd Aziz Dr Fatimatuzzahra' Binti , Ibrahim Baharudin
Published: February 2025

Dengue fever is known as a viral infection that is spread by several vectors, the most important of which is the Aedes mosquito (such as Aedes aegypti and Aedes albopictus) and is caused by the dengue virus (RNA virus) of the family Flaviviridae. DENV-1, DENV-2, DENV-3, and DENV-4 has main four serotype of the virus, In 2013 the fifth serotype was discovered DENN-5. Countries allocate a large budget to combat the disease because the disease has become a major public health problem, especially in recent decades due to the worsening of cases and the increase in numbers, especially among the population of Southeast Asia. The purpose of this review is to provide an overview of the dengue virus and investigate the role of non-structural proteins, in increasing disease severity. This study dealt with the damage resulting from the increase in disease severity on the hematological and immune systems, and explored the possibility that genetic factors contribute to the severity of the disease. In conclusion, there are differing opinions about the association of disease severity in dengue virus infection with non-structural proteins, but a significant role appears to exist for genetic factors in increasing the severity of the disease. due to the lack of focus on this type of research, the study recommends focusing on the role of NS1 )One of the non-structural proteins( in order to obtain exploratory results that contribute to reducing the severity of the disease or developing effective prevention methods against infection.
Creating safe environments for children: prevention of trauma in the Extended Verse
Authors: Jane Patel Nina
Published: February 2025

In the evolving landscape of digital childhood, ensuring safe environments within the Extended Verse (XV) is essential for preventing trauma and fostering positive experiences. This paper proposes a conceptual framework for the integration of advanced emotion recognition systems and physiological sensors with virtual and augmented reality technologies to create secure spaces for children. The author presents a theoretical architecture and data flow design that could enable future systems to perform real-time monitoring and interpretation of emotional and physiological responses. This design architecture lays the groundwork for future research and development of adaptive, empathetic interfaces capable of responding to distress signals and mitigating trauma. The paper addresses current challenges, proposes innovative solutions, and outlines an evaluation framework to support an empathic, secure and nurturing virtual environment for young users.
Assessment of Vocabulary Development in Preschool Children Using Peabody Picture Vocabulary Test-4
Authors: Tafseela Arshad  , Muhammad Azzam Khan  , Rooma Imtiaz  , Hina Ramzan  , Muhammad Tanveer  , Anum Ashraf
Published: February 2025

Background: Receptive vocabulary plays a crucial role in early language development and literacy skills. The Peabody Picture Vocabulary Test-4 (PPVT-4) is a standardized tool for assessing receptive vocabulary, but its applicability in non-native English-speaking populations, such as Pakistani preschoolers, remains underexplored. Objective: To assess receptive English vocabulary development in preschool children aged 3–5 years using the PPVT-4 and determine whether their vocabulary skills align with age expectations. Methods: A cross-sectional study was conducted on 278 preschool children from four private schools in Lahore, Pakistan. The PPVT-4 was administered individually to assess receptive vocabulary. Data were analyzed using SPSS 25.0, with descriptive statistics, independent t-tests, and chi-square tests applied. P < 0.05 was considered statistically significant. Results: The mean PPVT-4 score for the 36–48 months group was 80.1 ± 10.2, while for the 49–60 months group, it was 90.3 ± 10.5 (p < 0.001). Only 33.5% of older children had age-appropriate vocabulary, compared to 79.5% of younger children. Gender differences were not significant (p = 0.288). Conclusion: Preschool children exhibited significant delays in receptive English vocabulary, particularly in older age groups. Early language interventions are recommended to improve vocabulary acquisition in bilingual settings.
Assessing the usefulness of solid-phase microextraction (SPME) for methadone and its metabolites analysis in urine samples using HPLC/SPME fibre tips
Authors: AlFahmi Majidah Mahmoud
Published: February 2025

Solid-phase microextraction (SPME) has been introduced as a novel, simple and single- step technique of extracting methadone (MDN), 2-ethylidene-1,5-dimethyl-3,3- diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline (EMDP) from urine samples. In this study, direct immersion SPME followed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) was developed to identify methadone and its metabolites. The separation was performed on a Gemini C18 (octadecyl carbon chain) analytical column (150 x 2.0 mm, 5 µm) and detected by an ultraviolet (UV) detector at 210 nm. The factors influencing the SPME procedure, such as the sample’s pH, fibre coating type, salt addition and desorption solvent type were optimised. The best conditions were obtained with a C18 coating at a pH of 11, NaCl 15% and ethyl acetate.
The recoveries of MDN, EDDP and EMDP under optimum conditions were 90.8%, 89.3% and 86.5 %, respectively. The calibration curves for urine samples showed good linearity under optimum conditions (R² range 0.9983–0.9988) in a concentration range of 0.025–4 µg/mL for the analytes, using hydrocodone as the internal standard. All samples were analyzed using validated method. The selectivity of this method was evaluated and provided clean chromatograms with no interference in the analysis. Finally, the results show that the novel SPME fibre tips have relatively high extraction efficiency for methadone and its metabolites.
Necropolitics and Neocolonialism in International Assistance and Bias against People of Color
Authors: Dowlatshahi Tala
Published: February 2025

My main research focus is ethnographies and the lived experience of people of color, particularly women of color, working in the international assistance sector. As a senior global advisor focusing on decolonization and systemic change, I am driven to explore how to promote theories of change within this sector, which in my view continues to dehumanize the global South and to center the knowledge, “pragmatism,” and resilient capacity of the global North. Specifically, I argue that the colonial and current neocolonial approaches by the West contribute to the ongoing subjugation of bodies in the global South. This paper investigates the implications of necropolitics on people of color in the international humanitarian aid sector, analyzing how racial biases shape relations among workers within this sector while curtailing its ability to serve and empower communities within the global South.
Pawpaw: An Underutilized Tree with Potential
Authors: Erich Griffin , Peck Greg , Pritts Marvin
Published: February 2025

Pawpaw [Asimina triloba (L.) Dunal] is an endemic North American tree that is gaining commercial interest  because it produces desirable, nutritious fruit for human consumption. The plant evolved in the forest understory and can grow well in shaded and sunny environments. As a native tree, there are few arthropod pests or diseases, thus, the trees require few pesticide inputs. The acetogenins synthesized by the tree can be used as natural pesticides or in cancer therapy treatment. Pawpaw is primarily propagated by seed in nurseries, and cultivars are grafted via the whip-and-tongue and chip bud methods. However, there are several challenges that limit wider adoption of pawpaw production in North America including the lack of an adequate tissue culture protocol for clonal propagation, poor understanding of fruit physiology, and lack of rootstocks for commercial production. Modern biotechnology serves as viable option for overcoming these challenges and accelerating the development of pawpaw for commercial production.
Swipe, watch, engage
Authors: Cortés-Quesada Jose Antonio , Vizcaíno-Verdú Arantxa
Published: February 2025

The global impact of TikTok has prompted discussions digital consumption among youth. This study originated from this contentious context aimed at exploring the audio-visual consumption patterns of generation Alpha in thematic, audio-visual, and interactive terms. The analysis comprised 500 videos collected through the "For You Feed" of two 14-year-old individuals on the platform using quantitative content analysis. The findings reveal a predominance of humorous and dance-related content, along with a notable presence of advertising. It is noteworthy the popularity of the original content over promotional messages, with minimal employment of audio-visual techniques in the former case. These results underscore the relevance of understanding how new generations engage with digital content in an increasingly controversial and algorithm-dependent environment in contrast to governmental regulations and restrictions.
Una panorámica del legado historiográfico de Paola Barocchi: su aportación al digital turn de la literatura artística
Authors: Jaquero Esparcia Alejandro , Nastasi Martina
Published: February 2025

El presente artículo pretende analizar el papel historiográfico de la investigadora y profesora Paola Barocchi en la implementación de las Humanidades Digitales al estudio e investigación de la Historia del Arte. Una labor que comenzó en la segunda mitad del siglo XX, proponiendo una forma innovadora a la hora de trabajar y de acceder a las fuentes y recursos bibliográficos y que ha servido como base metodológica para muchos de los actuales proyectos de digitalización de archivos y documentación histórico-artística. Exponemos aquí datos de relevancia de dicho proceso, señalando las particularidades de sus iniciativas, la importancia que en ellos tuvo el tratamiento analógico de los textos y, para finalizar, una revisión sobre la continuidad de estos proyectos y su estado actual.
FERRER ORTS, Albert. Subtileses renaixentistes valencianes a colp d´ull. Xàtiva: Ulleye, 2022.
Authors: Romero Ricardo Santarrufina
Published: February 2025

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Multi-dimensionality of tree communities structure host-parasitoid networks and their phylogenetic composition
Authors: Wang Ming-Qiang , Guo Shi-Kun , Guo Peng-Fei , Yang Juan-Juan , Chen Guo-Ai , Chesters Douglas , Orr Michael , Niu Ze-Qing , Staab Michael , Chen Jing-Ting , Li Yi , Zhou Qing-Song , Fornoff Felix , Shi Xiaoyu , Li Shan , Martini Massimo , Klein Alexandra-Maria , Schuldt Andreas , Liu Xiaojuan , Ma Keping , Bruelheide Helge , Luo Arong , Zhu Chao-Dong
Published: February 2025

Environmental factors can influence ecological networks, but these effects are poorly understood in the realm of the phylogeny of host-parasitoid interactions. Especially, we lack a comprehensive understanding of the ways that biotic factors, including plant species richness, overall community phylogenetic and functional composition of consumers, and abiotic factors such as microclimate, determining host–parasitoid network structure and host–parasitoid community dynamics. To address this, we leveraged a five-year dataset of trap-nesting bees and wasps and their parasitoids collected in a highly-controlled, large-scale subtropical tree biodiversity experiment. We tested for effects of tree species richness, tree phylogenetic and functional diversity, and species and phylogenetic composition on species and phylogenetic diversity of both host and parasitoid communities and the composition of their interaction networks. We show that multiple components of tree diversity and canopy cover impacted both, species and phylogenetic composition of hosts and parasitoids. Generally, phylogenetic associations between hosts and parasitoids reflected non-randomly structured interactions between phylogenetic trees of hosts and parasitoids. Further, host-parasitoid network structure was influenced by tree species richness, tree phylogenetic diversity, and canopy cover. Our study indicates that the composition of higher trophic levels and corresponding interaction networks are determined by plant diversity and canopy cover especially via trophic links in species-rich ecosystems.
Review: Residual Compressive Strength Analysis of Fiber-Mixed Concrete Exposed to High Temperatures
Authors: Jang Younga , Nam Youngjin , Im Hajun , Kim Wonchang , Lee Taegyu
Published: February 2025

This study analyzed the high-temperature properties of concrete mixed with polypropylene (PP) and steel (ST) fibers, based on previous research cases. To examine the effects of different fiber types on concrete under high temperatures, fiber-mixed concrete was categorized into PP, ST, and PP+ST fibers, and the target concrete strengths were set at three levels: 40-60 MPa, 60-80 MPa, and 80-100 MPa. The temperature range for analysis was set at 20-900 °C, and the heating rate range was set at 0.5-20 °C/min. The residual strength of concrete exposed to high temperatures was analyzed based on target strengths and fiber types, and the results were compared with the CEB code. Based on the results of thermogravimetric analysis and differential scanning calorimetry, PP fibers were observed to melt at approximately 170 °C and vaporize at 341 °C, forming pores in the concrete matrix, whereas ST fibers underwent decarburization and carbonation at approximately 700 °C. Fiber-mixed concrete categorized by target strength showed that concrete with a target strength of 80-100 MPa had approximately 8% higher residual compressive strength at 600 °C compared with other target strength levels. The residual compressive strength analysis revealed that most concrete samples exhibited residual strength approximately 10%-31% higher compared with the CEB code above 600 °C.
Error Rates of Tunnel Fire Simulations According to Model Scale
Authors: Im Hajun , Kim Wonchang , Jeong Keesin , Lee Taegyu
Published: February 2025

Many experiments, including firefighting experiments, have been performed through simulations to observe representative trends. Numerous experiments have also been conducted by making scale models because of space limitations. Simulations and scale model experiments, however, have large errors compared with real-world full-scale experiments. In this study, we used the PyroSim software to calculate the error rate of simulations performed at reduced scales. The simulation was designed using Froude scaling from 1:1 to 1:2, 1:10, and 1:20 ratios considering a tunnel bus fire scenario. In the simulation results, the smoke arrival time at a certain location showed an increasing error rate as the scale reduced, and the temperature showed a similar tendency. The results of this study are expected to contribute to the efficient design of simulations and scale model experiments considering the a tradeoff between experiment costs and error rates.
Assessment of Stable Strains of Eri Silkworms (Samia ricini) for Commercial Silk Production under the Climate of Manipur
Authors: Devi Y Surjalata , Hossain Anowar , Devi W Sapana , Yumnam Debaraj , Majumdar Somdip , V S Raviraj
Published: February 2025

Aims: This study evaluates the performance of six Eri silkworm (Samia ricini) strains across multiple quantitative traits to identify the most suitable rearing period and stable strains for commercial silk production in Northeast India.
Study Design: A field experiment was conducted to assessed the productivity and stability of different Eri silkworm strains across four seasons.
Place and Duration of Study: The study was carried out in Imphal, Manipur, over four different rearing seasons.
Methodology: Six Eri silkworm strains were evaluated for eight quantitative traits, hatching percentage, fecundity, effective rate of rearing, larval weight, pupation rate, single shell weight, single cocoon weight and shell percentage. Data were collected across four seasons, and hierarchical clustering analysis was performed to classify the strains based on genetic and phenotypic similarities.
Results: The findings indicate that the April-May season provides optimal rearing conditions, resulting in higher survival rates, improved fecundity, and superior silk yield compared to other seasons. The Yellow Zebra strain performed consistently across multiple attributes and seasons, showing the highest stability among the strains that were studied. Hierarchical clustering analysis grouped the strains into three distinct clusters, reflecting their genetic and phenotypic relationships.
Conclusion: The identification of stable strains and optimal rearing periods is crucial for enhancing Eri silkworm productivity and sustainability. These findings provide a scientific basis for strain selection and breeding strategies, benefiting both farmers and researchers involved in Eri silk production.
Antimicrobial Textiles: Innovations, Challenges and Applications for Health and Hygiene
Authors: Kumari Bindu , Arya Nisha , Neeta  , Verma Pratishtha
Published: February 2025

Antimicrobial textiles have emerged as a key innovation in improving hygiene, health protection, and safety across various sectors, including healthcare, personal hygiene, food packaging, and industrial applications. These textiles are treated with antimicrobial agents, such as silver nanoparticles (AgNPs), copper compounds, zinc oxide (ZnO), quaternary ammonium compounds (QACs), and chitosan, to prevent microbial growth and enhance the durability of fabrics. Among these, silver and copper demonstrate broad-spectrum efficacy against bacteria, fungi, and viruses, while zinc oxide and QACs are particularly effective against bacterial contamination. Chitosan, a natural antimicrobial agent, offers biocompatibility and biodegradability, making it an attractive sustainable option. While antimicrobial textiles offer significant benefits, challenges remain in ensuring long-term efficacy, environmental safety, and affordability. One major concern is the degradation of antimicrobial properties after repeated washing or wear, which compromises their effectiveness. Also, regulatory inconsistencies and the lack of standardized testing protocols further complicate the widespread adoption of antimicrobial textiles. Ensuring compliance with global safety standards, such as those set by the EPA (Environmental Protection Agency), FDA (Food and Drug Administration), and ISO (International Organization for Standardization), is crucial for their safe and effective implementation. To address these challenges, ongoing research is focused on developing sustainable, biocompatible alternatives, such as plant-based and bio-based antimicrobial agents, including essential oils and peptides, as well as enhancing the durability of treatments through controlled-release technologies. Moreover, the integration of multifunctional properties, such as UV protection and water resistance, into antimicrobial textiles offers exciting future possibilities. The continued development of standardized testing methods and global regulatory frameworks will facilitate the safe and efficient use of antimicrobial textiles. Overall, these innovations are expected to play a critical role in promoting public health, safety and sustainability across industries.
Nutritional, Physical, and Sensory Evaluation of Wheat Flour Biscuits Supplemented with Bambara Groundnut and Bush Mango Flours
Authors: J. I. Okoye, , P. C. Okolo, , A. E. Egbujie,
Published: February 2025

This study was designed to evaluate the nutrient composition, microbiological, physical and sensory properties of biscuits produced from blends of wheat, Bambara groundnut and bush mango mesocarp flour. Bambara groundnuts and bush mango mesocarps were separately processed into flours. Each of the flours was used at varying replacement levels (5-30%) to complement wheat flour in the production of biscuits, with biscuits produced from 100% wheat flour as control. The nutrient composition, microbiological, physical and sensory properties of the biscuits were determined using standard methods. The moisture, crude protein, fat, crude fibre and ash contents of the biscuits increased significantly (p<0.05) with increased substitution of Bambara groundnut and bush mango mesocarp flours from 6.42-7.65%, 7.32-17.32%, 3.25-4.24%, 3.32-5.03% and 1.42-2.11, respectively with subsequent decrease in carbohydrate and energy contents. The mineral composition of the biscuits also increased significantly (p<0.05) with increase in the addition of Bambara groundnut and bush mango mesocarp flours from 77.86-133.27 mg/100g calcium, 95.47-167.72 mg/100g potassium, 89.11-147.26 mg/100g phosphorus, 57.54-116.04 mg/100g magnesium, 1.64-2.04 mg/100g iron and 1.43-1.91 mg/100g zinc. The niacin,  thiamine, riboflavin, vitamin A, ascorbic acid, and folic acid contents of the samples also ranged from 2.54-3.26 mg/100g, 2.57-3.47 mg/100g, 2.61-3.26 mg/100g, 3.23-4.36 mg/100g, 1.43-1.91 mg/100g and 1.12-1.71 mg/100g, respectively. The result showed that the vitamin contents of the composite biscuits increased gradually with increased substitution of Bambara groundnut and bush mango mesocarp flours. The microbial counts of the biscuit samples showed that the total viable count of the samples ranged from 0.32 x 104-1.20 x 104cfu/g, while the coliform and fungal counts were nil which is an indication that the products would be safe, wholesome and shelf-stable with adequate packaging and storage. The height, weight and thickness of the biscuit samples also showed significant (p<0.05) increase with increased substitution of Bambara groundnut and bush mango mesocarp flours, while the diameter, spread ratio and spread factor decreased. The sensory properties of the samples showed that the biscuits made from 100% wheat flour (Control) were most preferable to the panellists and also differed significantly (p<0.05) in colour, mouthfeel, flavour and crispiness.  In addition, the biscuits prepared from the composite flours were also acceptable because they were equally rated high by the judges in all the sensory attributes evaluated. The study, therefore, showed that the nutrient contents and some physical properties of wheat flour biscuits could be improved by the addition of Bambara groundnut and bush mango mesocarp flours at different stated levels in the preparation of biscuits.
Evaluation of the Anti-pyretic Effects of Ethanolic Extract of Sonchus wightianus DC Using Wistar Rats
Authors: Pal Dhawal , Patel Anant Kumar , Chouhan Sohan Singh
Published: February 2025

This study aimed to investigate the ethanolic extract of Sonchus wightianus DC for its pharmacological activities, including anti-pyretic, behavioral, and immunomodulatory effects. The extract was prepared via Soxhlet extraction, and its chemical composition was analyzed for bioactive compounds. The extract demonstrated significant antipyretic effects in both yeast-induced and vaccine-induced hyperpyrexia models in rats. Furthermore, behavioral tests revealed an increase in ambulation and rearing frequency compared to the negative control group. Additionally, a notable reduction in white blood cell (WBC) count was observed, suggesting potential immunomodulatory properties. These results support the medicinal potential of Sonchus wightianus DC in treating fever and modulating immune responses.
Transglutaminase and polyamine dependence of effector functions of human immunocompetent cells
Authors: Günzler Volkmar , Schopf Rudolf E. , Hanauske-Abel Hartmut M. , Schulte-Wissermann Hermann
Published: July 2002

The effects of the transglutaminase inhibitor dansyl cadaverine (DC) and the polyamine antagonist methyl glyoxal‐bis‐(guanylhydrazone) (MeGbG) on the response of lymphocytes towards allogeneic and lectin stimulation and on the zymosan‐induced chemiluminescence of neutrophilic granulocytes was studied. Application of DC resulted in dose‐dependent suppression of chemiluminiscence and lymphocyte proliferation; no difference of inhibitory potential occurred with variation of incubation time in the latter system. MeGbG was inactive in granulocytes, but inhibited lymphocyte proliferation; its effect increased with time. The experiments provide further evidence for the importance of transglutaminases and polyamines for the function of immunocompetent cells.
The mode of action of the antitumor drug bouvardin, an inhibitor of protein synthesis in eukaryotic cells
Authors: Zalacaín M. , Zaera E. , Vázquez D. , Jiménez A.
Published: July 2002

Bouvardain is an antitumor drug that inhibits protein synthesis in intact eukaryotic cells and cell‐free systems. Our present studies have shown that bouvardin acts at the level of the 80 S ribosome in a site somehow involved with the interaction of EF1 and EF2. Indeed bouvardin inhibits EF1‐dependent binding of aminoacyl‐tRNA and EF2‐dependent translocation of peptidyl‐tRNA but does not affect the non‐enzymic translocation since this relation does not require EF2. The site of the 80 S ribosome involved in the interaction with bouvardin appears to be independent from the cycloheximide and the cryptopleurine binding sites since yeast mutants resistant to cycloheximide or cryptopleurine are sensitive to bouvardin.
Synchronization of nuclear DNA synthesis in cultured Daucus carota L. cells by aphidicolin
Authors: Sala Francesco , Galli Maria Grazia , Nielsen Erik , Magnien Etienne , Devreux Marcel , Pedrali-Noy Guido , Spadari Silvio
Published: July 2002

By inhibiting the α‐like DNA polymerase, and therefore nuclear DNA synthesis, aphidicolin induces accumulation of suspension cultured carrot cells at the G1/S boundary of the cell cycle. After a 24‐h treatment with the drug the accumulation is complete, affecting all the cycling cells (95% of the population). Upon removal of the inhibitor, all cycling cells immediately resume nuclear DNA synthesis and move synchronously throughout the S‐phase.
Will the seven‐helix bundle be a common structure for integral membrane proteins?
Authors: Mohana Rao J.K. , Hargrave Paul A. , Argos Patrick
Published: July 2002

A prediction algorithm, designed to detect lipid‐embedded helical regions in membrane proteins, was applied to the amino acid sequence of a chloroplast thylakoid membrane protein important in photosynthesis. It is suggested that the thylakoid membrane protein consists of 7 transmembrane helices connected by exposed turn segments, similar to current models for bacteriorhodopsin and bovine rhodopsin. This basic structural feature, the 7‐helical bundle, may prove to be shared by many integral membrane proteins.
Analysis of in vitro and in vivo products of the TMV 30kDa open reading frame using antisera raised against a synthetic peptide
Authors: Kiberstis Paula A. , Pessi Antonello , Atherton Eric , Jackson Richard , Hunter Tony , Zimmern David
Published: July 2002

The peptide Tyr‐Ser‐Glu‐Ala‐Thr‐Val‐Ala‐Glu‐Ser‐ASP‐Ser‐Phe (the predicted C‐terminal 11 amino acids of the TMV 30kDa open reading frame plus an additional N‐terminal Tyr residue) was synthesized by solid phase methods and used to raise antisera in rabbits. These antisera precipitated 4 major proteins (p30, p28, p19 and 18.5kDa) from in vitro translation products of TMV short rod RNA , but only one, of apparent M
r = 30500, FROM TMV‐infected tobacco protoplasts. This protein was made between 8 and 16 h post infection, and had [35S]Met‐labelled tryptic peptides identical to those of in vitro synthesized p30.
Photoaffinity labeling of the azidoatrazine receptor site in reaction centers of Rhodopseudomonas sphaeroides
Authors: Vitry Catherine de , Diner Bruce A.
Published: July 2002

Photoaffinity labeling of photosynthetic reaction centers of Rhodopseudomonas sphaeroides by the herbicide inhibitor, azido[14C]atrazine, occurs principally on the L‐subunit. The specificity of labeling is greater at 77 than at 295 K. Kinetic studies of charge recombination in reaction centers indicate competition between azidoatrazine and ubiquinone‐1 (Q‐1) for binding to the reaction center. This competition occurs through the L‐subunit binding site, as increasing concentrations of Q‐1 decrease azido[14C]atrazine labeling of this site. It is proposed that the inhibitor binding site, predominantly on the L‐subunit, and the secondary quinone binding site on the M‐subunit, are adjacent so that there is partial overlap by one molecule of the domain occupied by the other.
Photoaffinity labelling of Ca2+ channels with [3H]azidopine
Authors: Ferry David R. , Rombusch Martin , Goll Alexandra , Glossmann Hartmut
Published: July 2002

A 1,4‐dihydroypyridine arylazide photoaffinity ligand, [3H]azidopine (50.6 Ci/mmol), has been synthesized. [3H]Azidopine binds reversibly with a K
d of 350 pM to guinea‐pig skeletal muscle membranes in the absence of ultraviolet light. The reversible [3H]azidopine binding is inhibited stereoselectively by 1,4‐dihydropyridines, phenylalkylamine Ca2+ channel blockers and La3+. Covalent incorporation into membrane proteins after photolysis was investigated by sodium dodecyl sulfate polyacrylamide slab gel electrophoresis. [3H]Azidopine is photoincorporated specifically into a protein of M
r∼145 000. The covalent labelling of the M
r ∼145 ooo band is inhibited stereoselectively by drugs and cations which block the reversible [3H]azidopine binding. It is suggested that [3H]azidopine is photoincorporated into a subunit of the putative Ca2+ channel.
Endogenous inhibitors of 4'‐[3H]chlorodiazepam (Ro 5‐4864) binding to ‘peripheral’ sites for benzodiazepines
Authors: Mantione Charles R. , Weissman Ben Avi , Goldman Mark E. , Paul Steven M. , Skolnick Phil
Published: July 2002

‘Peripheral’ binding sites for benzodiazepines are under neural or homonal control in the pineal gland, olfactory bulb, and kidney. These observations prompted a search for an endogenous substance which could modulate these sites under physiological conditions. Acidified methanol extracts from several tissues (e.g. stomach, kidney, lung) were found to inhibit the binding of [3H]Ro 5‐4864 to ‘peripheral’ binding sites, but did not significantly affect the binding of [3H]diazepam to ‘brain’ benzodiazepine receptors. Fractionation of a crude extract prepared from antral stomach by either ultrafiltration or gel filtration chromatography yielded high (M
r > 10000) and low (M
r < 1000) M
r fractions which competitively inhibited [3H]Ro 5‐4864 binding to ‘peripheral’ sites. These observations suggest the presence of endogenous substances in several rat tissues which may represent physiologically important ligands for ‘peripheral’ binding sites for benzodiazepines.
Inhibition of free radical‐induced DNA damage by uric acid
Authors: Cohen Arthur M. , Aberdroth Roy E. , Hochstein Paul
Published: July 2002

Single‐strand DNA breaks were produced in isolated rat liver nuclei incubated with 3 separate oxygen free radical generating systems: xanthine oxidase‐acetaldehyde plus Fe(II); hematin‐R(H)OOH; Fe(II)‐H2O2. Uric acid inhibited the induction of damage in the first two systems only. At concentrations below those found in human plasma, it was particularly effective against strand breaks produced by hematin‐cumene hydroperoxide. These results offer additional evidence that uric acid may function as a cellular protective agent against Superoxide and hydroperoxyl free radical‐induced cytotoxicity toxicity.
An opsonised microelectrode
Authors: Hill H.Allen O. , Tew David G. , Walton Nicholas J.
Published: July 2002

A 10 μm diameter gold microvoltammetric electrode, opsonised with human IgG, was used to study the respiratory burst of a single human neutrophil. The electrode oxidised Superoxide produced near its surface by the neutrophil back to dioxygen. It is suggested that the current so detected is proportional to the rate of Superoxide production by the NADPH oxidase of a single cell. In all cases the response consisted of a relatively rapid rise in current after cell addition, followed by a 2‐phase decay. It is further suggested that this complex decay results from the production of Superoxide being rate‐limited initially by the NADPH concentration and later by the coupled metabolism of the hexose monophosphate shunt.
The membrane‐anchoring systems of vertebrate acetylcholinesterase and variant surface glycoproteins of African trypanosomes share a common antigenic determinant
Authors: Stieger A. , de Almeida M.-L.Cardoso , Blatter M.-C. , Brodbeck U. , Bordier C.
Published: July 2002

Amphiphilic detergent‐soluble acetylcholinesterase (AChE) from Torpedo is converted to a hydrophilic form by digestion with phospholipase C from Trypanosoma brucei or from Bacillus cereus. This lipase digestion uncovers an immunological determinant which crossreacts with a complex carbohydrate structure present in the hydrophilic form of all variant surface glycoproteins (VSG) of T. brucei. This crossreacting determinant is also detected in human erythrocyte AChE after digestion with T. brucei lipase. From these results we conclude that the glycophospholipid anchors of protozoan VSG and of AChE of the two vertebrates share common structural features, suggesting that this novel type of membrane anchor has been conserved during evolution.
Extensive structural differences between genes for the α1 and α2 chains of type IV collagen despite conservation of coding sequences
Authors: Hostikka Sirkka Liisa , Tryggvason Karl
Published: July 2002

Analysis of the structure of the 3′‐end of the human α2(IV) gene demonstrated that the α1(IV) and α2(IV) genes have diverged extensively in spite of the apparent homology of the respective gene products. The NC‐1 domain and the 3′‐untranslated region are encoded by three exons in the α2(IV) gene but five exons in the α1(IV) gene. The two introns present in the NC‐ 1 domain coding part of the α2(IV) gene had the same location as two of the introns of the α1(IV) gene. The junction exon in the α2(IV) gene contains 53 bp coding for Gly‐X‐Y sequences whereas there are 71 bp in the α1(IV) gene. Three other Gly‐X‐Y coding exons studied from the human ⇌2(IV) gene have sizes that differ from corresponding exons in the α1(IV) gene and only one intron location matches here between the two genes. None of the exons studied has 54 bp or multiples thereof.
The initial phase of GnRH‐stimulated LH release from pituitary cells is independent of calcium entry through voltage‐gated channels
Authors: Smith Colleen E. , Wakefield I. , King Judy A. , Naor Z. , Millar R.P. , Davidson J.S.
Published: July 2002

Kinetic studies on gonadotropin‐releasing hormone (GnRH)‐stimulated luteinizing hormone (LH) release were undertaken using rat and chicken pituitary cell cultures. In response to continuous GnRH stimulation, a biphasic pattern of LH release was demonstrated. The two phases showed different susceptibility to the voltage‐gated Ca2+ channel blockers D600 and nifedipine. The first (transient) phase of LH release was unaffected by the Ca2+ channel blockers whereas the second (sustained) phase was inhibited by both drugs. These results indicate that the initial phase of LH release is independent of Ca2+ entry through voltage‐gated Ca2+ channels and may depend on mobilisation of intracellular Ca2+ or entry of extracellular Ca2+ through another mechanism.
Smooth muscle myosin phosphatase inhibition and force enhancement by black sponge toxin
Authors: Takai Akira , Bialojan Corinna , Troschka Monika , Caspar Rüegg J.
Published: July 2002

Smooth muscle contraction depends on the state of myosin phosphorylation and hence on the balance of myosin light chain kinase and phosphatase activity. Effects of okadaic acid isolated from black sponge on both enzyme activities and contractility were studied in chemically skinned fibers from guinea pig taenia coli. The toxin strongly inhibits myosin phosphatase and enhances tension development.
Evidence for PQQ as cofactor in 3,4‐dihydroxyphenylalanine (dopa) decarboxylase of pig kidney
Authors: Groen Barend W. , van der Meer Robert A. , Duine Joannis A.
Published: July 2002

Pig kidney 3,4‐dihydroxyphenylalanine (dopa) decarboxylase (EC 4.1.1.28) was purified to homogeneity. Treatment of the enzyme with phenylhydrazine (PH) according to a procedure developed for analysis of quinoproteins gave products which were identified as the hydrazone of pyridoxal phosphate (PLP) and the C(5)‐hydrazone of pyrroloquinoline quinone (PQQ). This method failed, however, in quantifying the amounts of cofactor. Direct hydrolysis of the enzyme by refluxing with hexanol and concentrated HCl led to detachment of PQQ from the protein in a quantity of 1 PQQ per enzyme molecule. In view of the reactivity of PQQ towards amines and amino acids, we postulate that it participates as a covalently bound cofactor in the catalytic cycle of the enzyme, in interplay with PLP. Since several other enzymes have been reported to show the atypical behaviour of dopa decarboxylase, it seems that the PLP‐containing group of enzymes can be subdivided into pyridoxoproteins and pyridoxo‐quinoproteins.
Efficient production of native, biologically active human cystatin C by Escherichia coli
Authors: Abrahamson Magnus , Dalbøge Henrik , Olafsson Isleifur , Carlsen Søren , Grubb Anders
Published: July 2002

A cDNA encoding the mature human cysteine proteinase inhibitor cystatin C was fused to the coding sequence for the Escherichia coli outer membrane protein A signal peptide, and the recombinant gene was expressed in E. coli under the control of the λ PR promoter, an optimized Shine‐Dalgarno sequence and the λ cI 857 repressor. When induced at 42°C, such cells expressed large amounts of recombinant cystatin C. The recombinant protein was isolated in high yield and characterized. All physicochemical properties investigated, including the positions of disulfide bonds, indicated that the E. coli derived cystatin C was identical to cystatin C isolated from human biological fluids, except that the proline residue in position three was not hydroxylated. The recombinant protein displayed full biological activity against papain, cathepsin B and dipeptidyl peptidase I.
Urodilatin (CDD/ANP‐95‐126) is not biologically inactivated by a peptidase from dog kidney cortex membranes in contrast to atrial natriuretic peptide/cardiodilatin (α‐hANP/CDD‐99‐126)
Authors: Gagelmann Michael , Hock Dieter , Forssmann Wolf-Georg
Published: July 2002

Atrial natriuretic peptide (CDD/ANP‐99‐126) is rapidly inactivated by a membrane preparation from dog kidney cortex. Inactivation occurs by cleavage of the ring structure in the position between Cys‐105 and Phe‐106. A unique proteolytic product separated by HPLC on reverse‐phase column appears as a single peak which elutes prior the intact peptide. In contrast, CDD/ANP‐95‐126 (urodilatin) which is released from the kidney is not destroyed by proteolysis using an identical membrane preparation.
Botulinum toxin‐induced ADP‐ribosylation and inhibition of exocytosis are unrelated events
Authors: Adam-Vizi V. , Rosener S. , Aktories K. , Knight D.E.
Published: July 2002

The hypothesis that inhibition of secretion by botulinum neurotoxin type D occurs by an intracellular process involving ADP‐ribosylation has been directly tested by measuring both the extent of inhibition of secretion and of ADP‐ribosylation in the same cells. Although the inhibitory effect of unpurified toxin closely parallels intracellular ribosylation, the two events are clearly unrelated, as using purified D and C3 toxins together with their antibodies, each of these events can be either stimulated or inhibited independently of each other.
Pyrroloquinoline quinone (PQQ) is the organic cofactor in soybean lipoxygenase‐1
Authors: van der Meer Robert A. , Duine Johannis A.
Published: July 2002

Treatment of soybean lipoxygenase‐1 (SLO) with phenylhydrazine (PH) induced inactivation and a maximum (350 nm) in the absorption spectrum of the enzyme. To detach the product having this absorption maximum, proteolysis was required. The product appeared to be the C(5) phenylhydrazone of pyrroloquinoline quinone (PQQ). Quantification showed that one covalently bound PQQ is present per enzyme molecule. Inspection of published spectroscopic data leads to the conclusion that the established cofactor of SLO, Fe, present as one ion per enzyme molecule, interacts with PQQ, the latter functioning as a terdentate ligand for the Fe ion (the N atom and COOH group of the quinoline ring together with the hydrated C(5) carbonyl group). If it is assumed that the substrate has two sites of interaction with this two‐cofactor complex, namely with the Fe ion and the C(5) carbonyl group of PQQ, the electron‐relay system generated very well explains the reported mechanistic features as well as inhibition effects of substrates with extended conjugation systems. The finding of PQQ in SLO is an additional indication that this cofactor is very versatile with respect to involvement in different types of redox reaction. A further implication might be that PQQ has been overlooked in other well‐known enzymes with an established cofactor but where the presence of this cofactor is unable to explain the mechanistic and spectroscopic features.
Import of a mutant mitochondrial precursor fails to respond to stimulation by a cytosolic factor
Authors: Randall Stephen K. , Shore Gordon C.
Published: July 2002

Import of the precursor to ornithine carbamyltransferase is stimulated by a partially‐purified, NEM‐sensitive soluble factor from rabbit reticulocyte lysate. A mutant in which the carboxy‐terminal 73 amino acids were deleted, had a sharply reduced response to this factor. The NEM‐sensitive, import‐stimulating factor interacts with the surface of mitochondria in the absence of precursor protein. Thus reticulocyte lysate contains an NEM‐sensitive, import stimulating factor which interacts both with the surface of mitochondria and whose activity appears to be dependent upon the structure of the mature portion of the precursor.
Alternative usage of different poly(A) addition signals for two major species of mRNA encoding human aromatase P‐450
Authors: Toda Katsumi , Terashima Masako , Mitsuuchi Yasuhiro , Yamasaki Yasuhisa , Yokoyama Yuichi , Nojima Shunji , Ushiro Hiroshi , Maeda Tomoho , Yamamoto Yasutake , Sagara Yusuke , Shizuta Yutaka
Published: July 2002

Two cDNA clones for human placental aromatase P‐450 (P‐450AROM) have been isolated and sequenced. The insert of one clone (2894 bp) contains an open reading frame encoding a protein consisting of 503 amino acid residues together with a 49 bp 5′‐untranslated stretch and a 1336 bp 3′‐noncoding region to which a poly(A) tract is attached. Three potential poly(A) addition signals are detected in this 3′‐noncoding region. The other clone contains a shorter cDNA insert, the nucleotide sequence of which overlaps with most of the sequence of the longer cDNA insert (nucleotides 36–2355) except for one nucleotide substitution. The 3′‐noncoding region of this shorter cDNA is only 846 bp in length, but a poly(A) tract is also attached to its 3′‐terminus. Northern blot analysis of human placental RNA reveals the presence of two major mRNA species of 3.4 and 2.9 kb when probes excised from the overlapping region of these two cDNAs are employed. The 2.9 kb mRNA is not detected, however, when a fragment of the non‐overlapping region of the longer cDNA is used as a probe. It is therefore concluded that the two major species of P‐450AROM mRNA are formed as a consequence of alternative processing of precursor mRNA(s).
Interaction of smooth muscle caldesmon with S‐100 protein
Authors: Skripnikova Elena V. , Gusev Nikolai B.
Published: July 2002

The interaction of caldesmon with certain Ca‐binding proteins was investigated by means of electrophoresis under non‐denaturating conditions. In the presence of Ca2+ calmodulin, troponin C and S‐100 protein form a complex with caldesmon. No complex formation takes place in the absence of Ca2+. Lactalbumin and pike parvalbumin (pI4.2) do not interact with caldesmon independently of Ca‐concentration. Both S‐100 protein and calmodulin effectively inhibit phosphorylation of caldesmon by Ca‐phospholipid‐dependent protein kinase. At low ionic strength S‐100 protein reverses the inhibitory action of caldesmon on the skeletal muscle acto‐heavy meromyosin ATPase more effectively than calmodulin. It is supposed that in certain tissues and cell compartments the proteins belonging to the S‐100 family are able to substitute for calmodulin in the caldesmondependent regulation of actin and myosin interaction.
Enhanced expression of group II phospholipase A2 gene in the tissues of endotoxin shock rats and its suppression by glucocorticoid
Authors: Nakano Tohru , Arita Hitoshi
Published: July 2002

We studied the regulation of group II phospholipase A2 (PLA2‐II) gene in vivo, using endotoxin shock rat as a model for systemic inflammation. Administration of endotoxin into rats increased PLA2 activity in the plasma, as described by Vadas and Hay, using endotoxin‐challenged rabbit. Specific absorption of this activity by anti‐PLA2‐II antibody indicated that the released PLA2 was PLA2‐II. The levels of PLA2‐II mRNA were elevated in the aorta, spleen, lung, and thymus but not in the liver and kidney. The tissues with high PLA2‐II mRNA contents released a greater amount of PLA2‐II than the tissues of control rats. These results suggest that in endotoxin shock rats, PLA2‐II is synthesized de novo in the above tissues and released into circulation. Furthermore, our present study demonstrates that glucocorticoid suppresses the enhanced expression of the PLA2‐II gene in the tissues of endotoxin shock rats.
Interferon‐γ binds to heparan sulfate by a cluster of amino acids located in the C‐terminal part of the molecule
Authors: Lortat-Jacob Hugues , Grimaud Jean-Alexis
Published: July 2002

Using three different approaches (domain mapping with monoclonal antibodies, limited enzymatic digestion and competition with synthetic peptides), we demonstrated that a cluster of basic amino acids on interferon‐γ is involved in its binding to heparan sulfate. This cluster (Lys131=Arg121) is localized in the C‐terminal part of IFN‐γ. Once bound to heparan sulfate, IFN‐γ is protected against protease attack.
Canine hydrophobic surfactant polypeptide SP‐C A lipopeptide with one thioester‐linked palmitoyl group
Authors: Johansson Jan , Persson Per , Löwenadler Björn , Robertson Bengt , Jörnvall Hans , Curstedt Tore
Published: July 2002

The amino acid sequence and the posttranslational modification of the hydrophobic surfactant polypeptide SP‐C from canine, rabbit and bovine lungs were established by direct sequence analysis and plasma‐desorption time‐of‐flight mass spectrometry. The results reveal that canine SP‐C has only one cysteine residue which, however, is palmitoylated, like the two Cys residues in other characterized SP‐C molecules. In addition, canine SP‐C is N‐terminally truncated, with only 34 amino acid residues in its longest form. Thus, SP‐C molecules can apparently vary to some extent in the N‐terminal lipid modified part, whereas the extremely hydrophobic middle and C‐terminal parts are well conserved.
Identification and characterization of urokinase receptors in natural killer cells and T‐cell‐derived lymphokine activated killer cells
Authors: Nykjær Anders , Petersen Claus Munck , Møller Bjarne , Andreasen Peter A. , Gliemann Jørgen
Published: July 2002

Flourescence‐activated cell scanning analysis of human blood cells revealed novel urokinase receptors in large granular lymphocytes and a small subset of T‐cells (CD3+). Culturing of T‐cells with interleukin‐2 to generate CD3+ lymphokine‐activated killer cells caused a large increase in urokinase binding, suggesting that the urokinase receptor is an activation antigen. The receptor in lymphocytes was similar to that in monocytes with regard to size, affinity and ligand specificity, but did not mediate degration of urokinase‐inhibitor complexes. It is suggested that lymphocyte‐bound pro‐urokinase is activated, e.g. by the human T‐cell specific serine proteinase. HuTSP‐1, and thereby starts a cascade of plasminogen activation important for extravasation of the cells.