bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ELECTRON OPTICAL PROPERTIES AND ABERRATION THEORY OF A COMBINED MAGNETIC ROUND LENS AND DEFLECTION SYSTEM
Authors: XIMEN JI-YE
Published: November 2020

A combined magnetic round lens and deflection system with a superimposed field has been studied, and the power series expressions for the magnetic field is given. The electron trajectories are described in vector-form, and the Gaussian optical properties of the combined system discussed. By means of Fermat's principle general aberration formulae for the combined system have been derived. Equations for calculating the third-order aberration are given in compact matrix-form, hence they are suitable for numerical computation. This paper attempts to give a general theory of the combined system to provide guidance for designers of cathode ray tubes and electron optical instruments.
A PROPOSED PROCEDURE FOR DETERMINATION THE DECAY WIDTH ΓX→2γ OF THE NEW PARTICLE X(2800) TO 2γ BY COULUMB PHOTOPRODUCTION OF THIS PARTICLE
Authors: CHEN XI-YOU  , DENG ZHI-FANG  ,   北京大学物理系,工农兵学员
Published: November 2020

The 2γ width of X(2.8) which is observed as a decay product of J (3.095) can be determined from high energy Coulumb photoproduction of this particle on nu-cleons and nucleus. The pertinent Feynman diagrams are discussed, the related coupling constants are analized and estimated, and the differential photo-production crossections from 0-3° of 50 and 100 GeV γ on proton (and also 100 GeV γ on the nucleus of lead) are calculated. The results show that if the decay width is not much less than 1 keV, then it can be determined accurately by this Coulumb photo-production measurement.
THERMALLY INDUCED BIREFRINGENCE IN YAG RODS IN THE (001) DIRECTION
Authors: LASER CRYSTALS RESEARCH GROUP  ,   中国科学院上海光学精密机械研究所
Published: November 2020

The principal axes of thermally induced birefringence in YAG laser rods generally do not possess axial symmetry because the strain-optic tensor of YAG crystals is different from that of isotropic materials A calculation is given for the (001) direction, the results of which are supported by experiments in which it was found that for CW or high repetition rate pulsed operation the transmission loss of (001) rods is lower than that of (111) rods. The polarized output of YAG lasers in which a polarizer was placed in the cavity was maximum where the transmission loss was minimum.
Maternal cortisol is associated with neonatal amygdala microstructure and connectivity in a sexually dimorphic manner
Authors: Stoye David Q , Blesa Manuel , Sullivan Gemma , Galdi Paola , Lamb Gillian J , Black Gill S , Quigley Alan J , Thrippleton Michael J , Bastin Mark E , Reynolds Rebecca M , Boardman James P
Published: November 2020

The mechanisms linking maternal stress in pregnancy with infant neurodevelopment in a sexually dimorphic manner are poorly understood. We tested the hypothesis that maternal hypothalamic-pituitary-adrenal axis activity, measured by hair cortisol concentration (HCC), is associated with microstructure, structural connectivity, and volume of the infant amygdala. In 78 mother-infant dyads, maternal hair was sampled postnatally, and infants underwent magnetic resonance imaging at term-equivalent age. We found a relationship between maternal HCC and amygdala development that differed according to infant sex. Higher HCC was associated with higher left amygdala fractional anisotropy (β = 0.677, p=0.010), lower left amygdala orientation dispersion index (β = −0.597, p=0.034), and higher fractional anisotropy in connections between the right amygdala and putamen (β = 0.475, p=0.007) in girls compared to boys. Furthermore, altered amygdala microstructure was only observed in boys, with connectivity changes restricted to girls. Maternal cortisol during pregnancy is related to newborn amygdala architecture and connectivity in a sexually dimorphic manner. Given the fundamental role of the amygdala in the emergence of emotion regulation, these findings offer new insights into mechanisms linking maternal health with neuropsychiatric outcomes of children.
Spatially resolved dendritic integration: towards a functional classification of neurons
Authors: Kirch Christoph , Gollo Leonardo L.
Published: November 2020

The vast tree-like dendritic structure of neurons allows them to receive and integrate input from many neurons. A wide variety of neuronal morphologies exist, however, their role in dendritic integration, and how it shapes the response of the neuron, is not yet fully understood. Here, we study the evolution and interactions of dendritic spikes in excitable neurons with complex real branch structures. We focus on dozens of digitally reconstructed illustrative neurons from the online repository NeuroMorpho.org, which contains over 130,000 neurons. Yet, our methods can be promptly extended to any other neuron. This approach allows us to estimate and map specific and heterogeneous patterns of activity observed across extensive dendritic trees with thousands of compartments. We propose a classification of neurons based on the location of the soma (centrality) and the number of branches connected to the soma. These are key topological factors in determining the neuron’s energy consumption, firing rate, and the dynamic range, which quantifies the range in synaptic input rate that can be reliably encoded by the neuron’s firing rate. Moreover, we find that bifurcations, the structural building blocks of complex dendrites, play a major role in increasing the dynamic range of neurons. Our results provide a better understanding of the effects of neuronal morphology in the diversity of neuronal dynamics and function.
DPM1 expression as a potential prognostic tumor marker in hepatocellular carcinoma
Authors: Li Ming , Xia Shengli , Shi Ping
Published: November 2020

Background

Altered glycosylation of proteins contributes to tumor progression. Dolichol phosphate mannose synthase (DPMS), an essential mannosyltransferase, plays a central role in post-translational modification of proteins, including N-linked glycoproteins, O-mannosylation, C-mannosylation and glycosylphosphatidylinositol anchors synthesis. Little is known about the function of DPMS in liver cancer.

Methods

The study explored the roles of DPMS in the prognosis of hepatocellular carcinoma using UALCAN, Human Protein Atlas, GEPIA, cBioPortal and Metascape databases. The mRNA expressions of DPM1/2/3 also were detected by quantitative real-time PCR experiments in vitro.

Results

The transcriptional and proteinic expressions of DPM1/2/3 were both over-expressed in patients with hepatocellular carcinoma. Over-expressions of DPMS were discovered to be dramatically associated with clinical cancer stages and pathological tumor grades in hepatocellular carcinoma patients. In addition, higher mRNA expressions of DPM1/2/3 were found to be significantly related to shorter overall survival in liver cancer patients. Futhermore, high genetic alteration rate of DPMS (41%) was also observed in patients with liver cancer, and genetic alteration in DPMS was associated with shorter overall survival in hepatocellular carcinoma patients. We also performed quantitative real-time PCR experiments in human normal hepatocytes and hepatoma cells to verify the expressions of DPM1/2/3 and results showed that the expression of DPM1 was significantly increased in hepatoma cells SMMC-7721 and HepG2.

Conclusions

Taken together, these results suggested that DPM1 could be a potential prognostic biomarker for survivals of hepatocellular carcinoma patients.
Wnt16 signaling promotes osteoblast differentiation of periosteal derived cells in vitro and in vivo
Authors: Jin Ying , Sun Xiaoyan , Pei Fang , Zhao Zhihe , Mao Jeremy
Published: November 2020

Background

Periosteum plays critical roles in de novo bone formation and fracture repair. Wnt16 has been regarded as a key regulator in periosteum bone formation. However, the role of Wnt16 in periosteum derived cells (PDCs) osteogenic differentiation remains unclear. The study goal is to uncover whether and how Wnt16 acts on the osteogenesis of PDCs.

Methods

We detected the variation of Wnt16 mRNA expression in PDCs, which were isolated from mouse femur and identified by flow cytometry, cultured in osteogenic medium for 14 days, then knocked down and over-expressed Wnt16 in PDCs to analysis its effects in osteogenesis. Further, we seeded PDCs (Wnt16 over-expressed/vector) in β-tricalcium phosphate cubes, and transplanted this complex into a critical size calvarial defect. Lastly, we used immunofluorescence, Topflash and NFAT luciferase reporter assay to study the possible downstream signaling pathway of Wnt16.

Results

Wnt16 mRNA expression showed an increasing trend in PDCs under osteogenic induction for 14 days. Wnt16 shRNA reduced mRNA expression of Runx2, collage type I (Col-1) and osteocalcin (OCN) after 7 days of osteogenic induction, as well as alizarin red staining intensity after 21days. Wnt16 also increased the mRNA expression of Runx2 and OCN and the protein production of Runx2 and Col-1 after 2 days of osteogenic stimulation. In the orthotopic transplantation assay, more bone volume, trabecula number and less trabecula space were found in Wnt16 over-expressed group. Besides, in the newly formed tissue Brdu positive area was smaller and Col-1 was larger in Wnt16 over-expressed group compared to the control group. Finally, Wnt16 upregulated CTNNB1/β-catenin expression and its nuclear translocation in PDCs, also increased Topflash reporter luciferase activity. By contrast, Wnt16 failed to increase NFAT reporter luciferase activity.

Conclusion

Together, Wnt16 plays a positive role in regulating PDCs osteogenesis, and Wnt16 may have a potential use in improving bone regeneration.
Modelling the effects ofSpartina alterniflorainvasion on the landscape succession of Yancheng coastal natural wetlands, China
Authors: Dai Lingjun , Liu Hongyu , Wang Gang , Wang Cheng , Guo Ziru , Zhou Yi , Li Yufeng
Published: November 2020

Background

The Yancheng coastal natural wetlands (YCNR) are well-preserved silty tidal flat wetlands in China. Due to the severe invasion ofSpartina alterniflora, the native ecosystem has undergone great changes. The successful invasion ofS. alterniflorareduced the biodiversity of the YCNR, changed the structure and function of the local ecosystem, and eventually led to the degradation of the ecosystem and the loss of ecosystem function and service. Fully understanding the impact of an alien species invasion on YCNR succession is an important prerequisite for protecting and restoring the wetlands.

Methods

In this study, remote sensing, GIS technology, and a cellular-automaton Markov model were used to simulate the natural succession process of native ecosystems without being affected by alien species. By comparing the landscape of the YCNR with the model simulation results, we gained a better understanding of how alien species affect native landscape-scale ecosystems.

Results

During the natural succession of the coastal native wetland ecosystem in the YCNR, the pioneer speciesS. alternifloraoccupied the mudflats and expanded seaward. The whole area expanded and moved seaward with an average annual movement of 58.23 m. Phragmites australis seemed to dominate the competition withS. salsacommunities, and the area gradually expanded with an average annual movement of 39.89 m. The invasion ofS. alterniflorachanged the native ecosystem’s spatial succession process, causing theS. salsaecosystem to be stressed by ecosystems on the side of the sea (S. alterniflora) and that of land (P. australis). The area of the seaward-expandingP. australisecosystem has been declining. Under a reasonable protected area policy, human activities have enhanced the succession rate of the P. australis ecosystem and have had a small impact on the ecological spatial succession ofS. salsaandS. alterniflora.
Evaluation of Income and Postharvest Losses of Yam in Southern Agricultural Zone of Nasarawa State
Authors: Iorzua Daniel Akaakohol , Ikwuba Agnes Agbanugo , Aan James Timbee , Nwafor Solomon Chimela
Published: November 2020

The study evaluated the income and postharvest losses of yam in Nasarawa State Nigeria from 2014 to 2018. The study employed the use of cross sectional design. The study was conducted in Nasarawa state, Nigeria between October 2019 and June 2020. Data for the study were collected using multistage sampling technique from a sample of three hundred and eighty seven (387) respondents. The result showed that majority of the respondents (322) 83%, were male, and within the age range of 31-40 years 158(41%) followed by the age bracket of 41-50: 97(25%); 323(84%) of the respondents were married with average household size of 8.0 persons per household while 87% of the respondents have had one form of formal education or the other. The spearman correlation matrix showing the relationship between the income and post-harvest losses of the farmers further revealed that there is a significant relationship between income and postharvest losses of yam farmers in the studied area. Coefficient of determination (R square) value was 0.922 with a P value of 0.00. The result reveals a significant and strong positive correlation betweenthe income and post-harvest losses of the farmers. The study thus concluded that most of the respondents were high income earners but suffer post-harvest losses throughout yam production chain in various measures. The extent of losses differs from farmer to farmer but does not differ in the communities sampled in the study area.
Innovative Shift in Smart Learning Environment
Authors: Hawedi Hadya S. , Abdullah Abdulghader Abu Reemah A.
Published: November 2020

Innovations in smart learning represent a domain of knowledge transfer platform to boost the effectiveness of the educational practices and learning outcome. The uniqueness of this form of electronic-assisted has been widely accepted as it provides its users with a powerful multi-search tool to access learning content that meet their intended needs. The transformative changes in the learning platform provide a flexible teaching/learning online outlet that has increasingly been adopted to improve learning outcome. In this study, the effectiveness of innovation in information and communication technologies (ICT) as a platform to rapidly transformed learning environment is discussed. Potential of smart learning environment is discussed and relevance of its flexibility in the learning environment and adaptable features for training workers in an organizational setting. This review extensively highlights the position of smart learning system in improving conventional learning and organizational practices that are limited in scope and their functioning environment.
Subordination Results for a Class of Analytic Functions Defined by Convolution
Authors: Adwan E. A.
Published: November 2020

Aims/ Objectives: In this paper, making use the Hadamard product , we introduce drive several interesting subordination results for a new class of analytic function. Furthermore, we mention some known and new results, which follow as special cases of our results.
Association between Subclinical Hypothyroidism and Albuminuria in Patients with Type 2 Diabetes Mellitus: A Cross Sectional Study in Iran
Authors: Najmaldin Atousa , Askari Solmaz , Foroutan Majid
Published: November 2020

Introduction: Studies have shown the association between subclinical hypothyroidism and type 2 diabetes. However, the common complications of type 2 diabetes, such as diabetic nephropathy and albuminuria with subclinical hypothyroidism, are not fully clear yet. This study thus aimed to determine the association between subclinical hypothyroidism and albuminuria in patients with type 2 diabetes mellitus.

Methods: This was a cross-sectional study, of 140 individuals diagnosed with type 2 diabetes mellitus (DM) admitted to the internal clinics of Kosar Hospital in Semnan, Iran in 2017-2018. The participants were selected, and were compared based on having 2 TSH levels above normal (>4.2 mIU/L) 3 months apart, as well as patients were divided to two groups including, subclinical hypothyroidism group (n=40) and euthyroid group (n=100) based on demographic information, laboratory information and indicators such as albuminuria, and urinary albumin-to-creatinine ratio (UACR).

Findings: The mean and standard deviation of UACR in patients with subclinical hypothyroidism were significantly higher than those of euthyroid patients (46.09 ± 27 9.27 vs. 3.94 ± 0.24 and P = 0.015, respectively). In patients with subclinical hypothyroidism, there was a statistically significant and direct relationship between UACR values with primary TSH level (r = 0.555, P< 0.001) and UACR values with secondary TSH level (r = 0.563, P< 0.001).

Conclusion: Among type 2 DM patients, the rate of albuminuria in subclinical hypothyroidism group was significantly higher than that of euthyroid patients and with increasing initial and recurrent TSH levels, UACR values and consequently albuminuria increased.
How good are predictions of protein secondary structure?
Authors: Kabsch Wolfgang , Sander Christian
Published: July 2002

The three most widely used methods for the prediction of protein secondary structure from the amino acid sequence are tested on 62 proteins of known structure using a program package and data collection not previously available. None of these methods predicts better than 56% of the residues correctly, for a three state model (helix, sheet and loop). The algorithms of Robson [J. Mol. Biol. (1978) 120, 97–120] and Lim [J. Mol. Biol. (1974) 88, 873–894] are the best of those tested. New methods, now under development, can be tested against this benchmark.
Inhibition study of ADP,ATP transport in mitochondria with trinitrophenyl‐modified substrates
Authors: Schlimme E. , Boos K.-S. , Onur G. , Ponse G.
Published: July 2002

The ADP,ATP carrier of rat liver mitochondria is specifically inhibited by Meisenheimer‐type trinitrophenyl (TNP) derivatives of ADP and ATP. Due to a systematic inhibition study we could show that the TNP‐moiety itself, even in the 2′, 3′‐O‐cyclic Meisenheimer complex, revealed no inhibition of mitochondrial ADP,ATP transport. Nucleosidic TNP‐compounds are weak inhibitors. Introduction of a phosphate group at the 5′‐position, however, enhances the inhibitory power markedly. Our findings point to a synergistic effect of the 5′‐phosphate chain and the TNP‐moiety. Irreversible inhibition by TNP‐nucleotides can be ruled out due to the fact that the inhibited ADP,ATP‐transport system is fully reactivated by addition of albumin.
Characterization of a new membrane‐bound cytochrome c of Rhodopseudomonas capsulata
Authors: Hüdig Hendrik , Drews Gerhart
Published: July 2002

A cytochrome c (cyt. c) was solubilized with Triton‐X‐100 and co‐purified with cytochrome c oxidase from membranes of chemotrophically grown cells of Rhodopseudomonas capsulata. Cyt. c and cytochrome oxidase were separated on Sephadex G‐50 columns. Antibodies against cytochrome c
2 from the same bacterium did not cross react with the membrane‐bound cyt. c. The IEP of the membrane‐bound cyt. c was found to be pH 8.2 the midpoint potential was 234 ± 11 mV at pH 7.0. This cyt. c binds CO. The native cyt. c is a dimer with an apparent M
r of 25 000 containing 2 mol heme per mol dimer, which is believed to function as an electron donor for the high‐potential cytochrome c oxidase.
The effect of cross‐innervation on the tropomyosin composition of rabbit skeletal muscle
Authors: Heeley D.H. , Dhoot G.K. , Frearson N. , Perry S.V. , Vrbova G.
Published: July 2002

Soleus, semitendinosus and crureus muscles of the rabbit were found to contain α‐ and β‐tropomyosin subunits and additional forms that have been provisionally designated γ and δ. Extensor digitorum longus and psoas muscles contained only α and β subunits, the relative proportions of which varied between single fibres of psoas muscle. On cross‐innervation of rabbit soleus and extensor digitorum longus muscles, the fraction of the total tropomyosin present as the β subunit remained constant. The relative proportions of α, γ and δ subunits changed as would be expected from the change in speed that occurred.
Hemoglobin Kariya [α40 (C5) Lys → Glu]: a new hemoglobin variant with an increased oxygen affinity
Authors: Harano T. , Harano K. , Shibata S. , Ueda S. , Imai K. , Tsuneshige A. , Yamada H. , Seki M. , Fukui H.
Published: July 2002

A new abnormal hemoglobin, Hb Kariya [α40 (C5) Lys → Glu], with an amino acid substitution at the α1β2 contact was discovered in a young Japanese man. This variant migrated to the anode faster than Hb A, being nearly the same as Hb I in electrophoretic mobility. It amounted to about 6% of the total hemoglobin of the hemolysate. This hemoglobin showed an increased oxygen affinity, decreased heme—heme interaction and a lowered 2,3‐DPG effect.
In vitro evidence for CCl4 metabolites covalently bound to lipoprotein micelles
Authors: Poli G. , Albano E. , Biasi F. , Chiarpotto E. , Dianzani M.U.
Published: July 2002

CCl4‐induced impairment of the lipoprotein secretion pathway of intact rat hepatocytes was carried out using 14CCl4 to check the possibility of binding to lipoproteins by CCl4 metabolites. After separation of different cell suspension fractions by means of ultracentrifugation and chemical precipitation procedures, a significant amount of the radioisotope was found covalently bound to the lipid and protein components of low density lipoproteins. Suitable experiments demonstrated that the bound radioisotope was represented by CCl4 metabolites and not by unactivated CCl4.
Antioxidant properties of caeruloplasmin towards iron‐ and copper‐dependent oxygen radical formation
Authors: Gutteridge John M.C.
Published: July 2002

The antioxidant activity of caeruloplasmin can be mainly ascribed to its ferroxidase activity which effectively inhibits ferrous ion‐stimulated lipid peroxidation and ferrous ion‐dependent formation of hydroxyl radicals in the Fenton reaction. In addition, caeruloplasmin can prevent copper ions from stimulating lipid peroxidation.
Multi‐site phosphorylation of bovine kidney branched‐chain 2‐oxoacid dehydrogenase complex
Authors: Cook Kenneth G. , Lawson Rowena , Yeaman Stephen J.
Published: July 2002

The α‐subunit of the E1 component of branched‐chain 2‐oxoacid dehydrogenase is phosphorylated at 3 sites by an endogenous kinase. Inactivation of the complex correlates with rapid phosphorylation of one of these sites. The similarities with the covalent regulation of pyruvate dehydrogenase complex are discussed.
A new potentiator of insulin action
Authors: Kobayashi Masashi , Iwasaki Makoto , Ohgaku Seiji , Maegawa Hiroshi , Watanabe Nobuyuki , Shigeta Yukio
Published: July 2002

A new potentiator of insulin action, 5‐[4‐(1‐methylcyclohexylmethoxy)‐benzyl]thiazolidine‐2,4‐dione, was tested for activation of insulin action in vitro. The agent (50 mg.kg−1.day−1) was orally administered to rats for 14 days and adipocytes from treated rats were used to assess insulin‐binding, glucose uptake and glucose oxidation. In obese rats, the agent increased glucose uptake and oxidation without any change in insulin binding, whereas in lean or streptozotocin‐treated rats it failed to increase glucose metabolism. Fat tissues were cultured with the agent for 24 h and were tested for insulin action. In the presence of insulin (10 ng/ml) in the culture media, the agent increased glucose oxidation in these cells without any change in insulin binding. However, without insulin in the culture media the agent did not increase glucose oxidation. Thus, the agent appeared to potentiate insulin action at the post receptor process.
‘Molten‐globule“ state accumulates in carbonic anhydrase folding
Authors: Dolgikh D.A. , Kolomiets A.P. , Bolotina I.A. , Ptitsyn O.B.
Published: July 2002

Kinetics of folding and unfolding of bovine carbonic anhydrase B were monitored by circular dichroism, viscometry and esterase activity. It was shown that kinetic intermediate states accumulating in folding process reveal a native‐like compactness and secondary structure but have a symmetrized average environment of aromatic side groups and no esterase activity. These properties allow one to consider these intermediate states as the ‘molten‐globule“ state of a protein molecule previously described by us for several equilibrium forms of bovine and human α‐lactalbumins and bovine carbonic anhydrase B.
Electron microscopy of beef heart mitochondrial F1‐ATPase
Authors: Tsuprun V.L. , Mesyanzhinova I.V. , Kozlov I.A. , Orlova E.V.
Published: July 2002

The quaternary structure of isolated and membrane‐bound F1‐ATPase (submitochondrial particles) has been studied by electron microscopy. A model of the molecule has been proposed: six protein masses are arranged in two layers approximately at the vertices of a triangular antiprism. Computer averaging of the images showed that the frontal view of the molecule can be approximately characterized by mirror plane symmetry.
Testing the classical two‐tRNA‐site model for the ribosomal elongation cycle
Authors: Spirin Alexander S.
Published: July 2002

An experimental system where the elongation of a polypeptide (polyphenylalanine) is performed stepwise and synchronously by purified Escherichia coli ribosome in a matrix‐coupled poly(U) column is proposed for testing the number of non‐overlapping tRNA binding sites on the elongating ribosome. If phenylalanyl[3H]tRNA is introduced into the column and bound with the ribosomes at the beginning of a given elongation cycle, deacylated [3H]tRNA is shown to be released from the ribosomes and comes out from the column at the translocation step of the next elongation cycle. The result obtained is fully predicted by the classical two‐tRNA‐site model and contradicts any model involving more than two non‐overlapping high‐affinity tRNA binding sites in the ribosomal elongation cycle.
EPR measurements on the effects of bicarbonate and triazine resistance on the acceptor side of Photosystem II
Authors: Vermaas Wim F.J. , Rutherford A.William
Published: July 2002

CO2 depletion leads to an approximately 10‐fold increase in the light‐induced EPR signal at g = 1.82, attributed to the QA
− · Fe2+ complex, in Photosystem II‐enriched thylakoid membrane fragments. Upon reconstitution with HCO3
−the signal decreases to the size in control samples. The split pheophytin− signal is broader in control or reconstituted than in CO2‐depleted samples. It is concluded that HCO2
− strongly influences the localization and conformation of the QA
− · Fe+ complex. The QA
− · Fe2+ and split pheophytirr− EPR signals from triazine‐resistant Brassica napus were virtually identical to those from triazine‐susceptible samples, indicating that the change in the 32‐kDa azidoatrazine‐binding protein does not lead to a confonnational change of the Qa
− · Fe2+ complex.
Isolation of the gene encoding pilin of Bacteroides nodosus (strain 198), the causal organism of ovine footrot
Authors: Elleman T.C. , Hoyne P.A. , Emery D.L. , Stewart D.J. , Clark B.L.
Published: July 2002

The gene for pilin, the monomeric protein subunit from which the pilus of Bacteroides nodosus is constructed, has been isolated. Isolation was achieved by cloning the fragmented genome of B. nodosus in Escherichia coli RR1 using the plasmid vector pBR322. Pilin‐producing colonies were identified by screening with a colony immunoassay using antiserum from a sheep immunized against purified pili from B. nodosus strain 198, and were further characterized by immunoblot analysis. Final confirmation of the presence of the pilin gene was by nucleotide sequence data which translated to the known pilin amino acid sequence.
Some properties of membrane‐bound, solubilized and reconstituted into liposomes H+‐ATPase of vacuoles of Saccharomyces carlsbergensis
Authors: Lichko L.P. , Okorokov L.A.
Published: July 2002

Vacuoles of yeast grown in peptone medium possessed high ATPase activity (up to 1 μmol·mg protein‐1·min−1). Membrane‐bound and solubilized ATPase activities were insensitive to vanadate and azide, but were inhibited by NO3
−, K+ and cyclic AMP stimulated both membrane‐bound and solubilized ATPase activities. Dio‐9 activated the membrane form of vacuolar ATPase 1.5‐2‐fold and did not affect the solubilized enzyme. Solubilized and partially purified vacuolar ATPase was reconstituted with soy‐bean phospholipids by a freeze‐thaw procedure. ATPase activities in native vacuoles and proteoliposomes were stimulated effectively by Dio‐9, the protonophore FCCP and ionophores valinomycin and nigericin. ATP‐dependent H+ transport into proteoliposomes was also shown by quenching of ACMA fluorescence. Vacuolar and partially purified ATPase preparations possessed also GTPase activity. Unlike ATPase, however, GTPase was not incorporated as a proton pump into liposomes.
Mitochondrial membrane potential monitored in situ within isolated guinea pig brown adipocytes by a styryl pyridinium fluorescent indicator
Authors: Rafael J. , Nicholls D.G.
Published: July 2002

2‐(Dimethylaminostyryl)‐1‐methyl pyridinium, a fluorescent indicator of mitochondrial membrane potential, is accumulated up to 400‐fold by intact, isolated brown adipocytes from cold‐adapted guinea pigs. The indicator can be optically localized within the in situ mitochondria. Ionophores which would be predicted to lower or increase the in situ mitochondrial membrane potential lead to decreased and increased uptake, respectively, of the radio‐labelled indicator. Noradrenaline induces a 15 mV decrease in the sum of mitochondrial and plasma membrane potentials. The results indicate that the mitochondria within isolated brown adipocytes maintain a substantial membrane potential in the resting state, rather than being artifactually depolarized.
Molecular forms of glucagon‐like peptides in man
Authors: George S.K. , Uttenthal L.O. , Ghiglione M. , Bloom S.R.
Published: July 2002

Molecular forms of the glucagon‐like peptides (GLP) encoded by the human preproglucagon gene were analysed by chromatography combined with specific radioimmunoassays to the synthetic peptides. Whereas extracts of human pancreas and a glucagonoma contained a large proglucagon cleavage product possessing both GLP‐1 and GLP‐2 immunoreactivities, extracts of human intestine contained products corresponding to free GLP‐1 and a small amount ofchromatographically distinct GLP‐2 immunoreactivity. It is concluded that post‐translational processing of proglucagon differs in pancreas and intestine, so that the C‐terminal portion of the molecule is cleaved to liberate free GLP‐1 in the intestine. Further processing or degradation results in loss especially of GLP‐2 immunoreactivity.
Cyanogen‐induced γ‐glutamyl to imidazole cross‐link in carbonic anhydrase
Authors: Kirley Jane W. , Day Richard A. , Kreishman George P.
Published: July 2002

The irreversible inhibition of carbonic anhydrase by cyanogen occurs by a unique mechanism. Cyanogen is an affinity label: it behaves like a carbodiimide and produces an intra‐molecular cross‐link without being incorporated. The nucleophile‐labile cross‐link is formed between a γ‐COOH of a Glu and an imidazole of a His with a 1:1:1 stoichiometry with the enzyme. The deletion of ~ 1 Glu and ~ 1 His was noted by amino acid analysis of enzymatically hydrolyzed carbonic anhydrase. The modified Glu was converted to 2,4‐diaminobutanoic acid and quantitated by amino acid analysis. The presence and quantity of modified His was supported through high‐resolution proton NMR analysis.
Quaternary organization of subunits in the L‐leucine dehydrogenase from Bacillus cereus
Authors: Lünsdorf Heinrich , Tsai Hsin
Published: July 2002

L‐Leucine dehydrogenase from Bacillus cereus was examined in the electron microscope. The quaternary structure reveals a molecule that is built up from 8 subunits, identical in mass, arranged in 2 layers which are oriented mainly in a staggered form. In each layer subunits are positioned at the vertices of a square, leaving free a central protein‐deficient region of 2.6 nm in diameter. The enzyme measures 11.1 nm in diagonal and 9.0 nm in edge length. Mean subunit diameter is 4.0 nm. The overall shape is a cube, slightly compressed, with 90% edge length in height.
Superoxide dismutase in Drosophila melanogaster
Authors: Lee Young Moo , Ayala Francisco J.
Published: July 2002

Two electrophoretically distinguishable variants of Superoxide dismutase (SOD) are common in natural populations of Drosophila melanogaster. We have earlier comparatively characterized these two electromorphs, SODF and SODS By peptide mapping in high‐performance liquid chromatography (HPLC), we now show that the difference between the two electromorphs is due to the replacement of Asn‐96 (SODF) by Lys‐96 (SODs). It is far from clear how this replacement causes the biochemical differences (in thermostability, specific activity, and others) observed between these two forms of the enzyme.
Poly(A) polymerase and poly(ADP‐ribose) polymerase activities in normal and crown gall tumor tissue cultures of tobacco
Authors: D'Alessandro Michelle , Srivastava B.I.Sahai
Published: July 2002

Normal and crown gall tumor tissue cultures of tobacco had poly(ADP‐ribose) polymerase associated with the chromatin and two poly(A) polymerases (separable by DEAE‐Sephadex A‐25 chromatography) with the soluble fraction. The two poly(A) polymerases resembled mammalian enzymes in molecular mass (65–70 kDa), K
m
ATP (0.1–0.2 mM), primer and substrate preference (poly(A) and ATP, respectively), pH optimum (8–8.5), cation requirement (0.25 mM Mn2+/l mM Mg2+ = 5–15), inhibition by 3'‐dATP and spermine and lack of inhibition by α‐amanatin. Likewise the tobacco tumor tissue contained 4‐times higher activities of both poly(A) polymerases and 6‐times higher activity of poly(ADP‐ribose) polymerase as compared to the normal tissue indicating their enhanced function in transformed cells.
Selective localization of calpain I (the low‐Ca2+‐requiring form of Ca2+‐dependent cysteine proteinase) in B‐cells of human pancreatic islets
Authors: Kitahara Aiko , Ohtsuki Hitoshi , Kirihata Yoshiko , Yamagata Yoko , Takano Emiko , Kannagi Reiji , Murachi Takashi
Published: July 2002

An immunohistochemical study was performed to localize two distinct Ca2+‐proteases (low‐Ca2+‐requiring calpain I and high‐Ca2+‐requiring calpain II) and their specific inhibitor (calpastatin) in human pancreas using the respective monospecific antibodies. Strongly positive staining by anti‐calpain I antibody was found in pancreatic islets, specifically in B‐cells, whereas the exocrine pancreatic tissue showed essentially no positive immunostaining. No such specific staining was found with anti‐calpain II antibodies or anti‐calpastatin antibodies. The results suggest that the Ca2+‐dependent proteolysis in B‐cells can be triggered by a small rise of the intracellular Ca2+ concentration without serious interference by the endogenous inhibitor.
Structural model for interferons
Authors: Ptitsyn O.B. , Finkelstein A.V. , Murzin A.G.
Published: July 2002

Secondary structures of leucocyte α1‐ and α2‐interferons and of fibroblast β‐interferon are calculated using the molecular theory of protein secondary structures. The common secondary structure calculated for α‐ and β‐interferons is used to predict the three‐dimensional structures of fragments 1–110 and 111–166 of the chains (which are supposed to be quasi‐independent domains). The predicted structure of the active domain I (1–110) is an ‘up‐and‐down’ tetrahelical complex (in which the second helix is shorter than the others and can be absent in α1‐interferon) similar to the mirror image of myohaemoerythrin. The predicted structure of domain II (111–166) is either a three‐stranded β‐sheet screened from one side by two α‐helices or a three‐helical complex (similar to that in the N‐domain of papain), the first structure being more consistent with the circular dichroism data of α‐interferon and its C‐end fragment.
Comparative binding properties of linear and cyclic δ‐selective enkephalin analogues: [3H]‐[D‐Thr2, Leu5] enkephalyl‐Thr6 and [3H]‐[D‐Pen2, D‐Pen5] enkephalin
Authors: Delay-Goyet Philippe , Zajac Jean-Marie , Rigaudy Pascal , Foucaud Bernard , Roques Bernard P.
Published: July 2002

The range of δ‐selectivity of linear and cyclic analogues of enkephalin in rat brain was found to be: [D‐Pn5] enkephalin (DPLPE) > [D‐Pn5] enkephalin (DPDPE) > [D‐Thr2, Leu5] enkephalyl‐Thr6 (DTLET) > [D‐Ser2, Leu5] enkephalyl‐Thr6 (DSLET). Saturation experiments performed with [3H]DPDPE and [3H]DTLET in NG108‐15 cells and rat brain showed similar binding capacities for both the ligands, but the δ‐affinity of [3H]DTLET (K
D ≈ 1.2 nM) was much better than that of [3H]DPDPE (K
D ≈ 7.2 nM). The rather low δ‐affinity of DPDPE induced high experimental errors cancelling the benefit of its better δ‐selectivity. Binding experiments in rat or guinea‐pig brains showed, in both cases, the better δ‐selectivity of [3h]dtlet compared to [3h]slet. The former peptide remains at this time the most appropriate radioactive probe for binding studies of δ‐receptor.
Tissue expression and phylogenetic appearance of the β and γ subunits of GTP binding proteins
Authors: Audigier Y. , Pantaloni C. , Bigay J. , Deterre P. , Bockaert J. , Homburger V.
Published: July 2002

Guanyl nucleotide binding protein
Adenylate cyclase
Phototransduction
Hormonal transduction
Evidence that adrenaline activates key oxidative enzymes in rat liver by increasing intramitochondrial [Ca2+]
Authors: McCormack James G.
Published: July 2002

The effects of intramitochondrial Ca2+ on the activities of the Ca2+‐sensitive intramitochondrial enzymes, (i) pyruvate dehydrogenase (PDH) phosphate phosphatase, and (ii) oxoglutarate dehydrogenase (OGDH), were investigated in intact rat liver mitochondria by measuring (i) the amount of active PDH (PDHa) and (ii) the rate of decarboxylation of α‐[1‐14C]oxoglutarate (at non‐saturating [oxoglutarate]), at different concentrations of extramitochondrial Ca2+. In the presence of Na2+ and Mg2+, both PDH and OGDH could be activated by increases in extramitochondrial [Ca2+] within the expected physiological range (0.05–5 μM). When liver mitochondria were prepared from rats treated with adrenaline, and then incubated in Na‐free media containing EGTA, both PDH and OGDH activities were found to be enhanced. Evidence is presented that the activation of these enzymes by adrenaline is brought about by a mechanism involving increases in intramitochondrial [Ca2+].
The assignment of the Ca2+‐ATPase activity of chromaffin granules to the proton translocating ATPase
Authors: Flatmark Torgeir , Grønberg Martin , Husebye Eystein , Berge Sissel Vik
Published: July 2002

Ca2+‐ATPase
H+‐ATPase
Proton pump
Chromaffin granule
Adrenal medulla
The phorbol ester TPA prevents the expression of both glucagon desensitisation and the glucagon‐mediated block of insulin stimulation of the peripheral plasma membrane cyclic AMP phosphodiesterase in rat hepatocytes
Authors: Heyworth Clare M. , Wilson Sally P. , Gawler Debra J. , Houslay Miles D.
Published: July 2002

The phorbol ester TPA (12‐O‐tetradecanoyl phorbol‐13‐acetate) causes a dose‐dependent inhibition of the glucagon‐stimulated adenylate cyclase activity expressed in plasma membranes isolated from TPA‐treated hypatocytes. However, no observable inhibitory effect of TPA on adenylate cyclase activity was observed in cells which had been exposed to glucagon for 5 min, prior to isolation, to desensitise adenylate cyclase. The degree of inhibition of adenylate cyclase elicited by both glucagon desensitisation and TPA treatment of hepatocytes was identical. Pre‐treatment of hepatocytes with TPA was also found to prevent glucagon from blocking insulin's activation of the peripheral plasma membrane cyclic AMP phosphodiesterase in intact hepatocytes. TPA treatment also inhibited the ability of cholera toxin to activate the peripheral cyclic AMP phosphodiesterase in intact hepatocytes. It is suggested that in these particular instances TPA and glucagon elicit mutually exclusive processes rather than TPA mimicking glucagon desensitisation per se.
Lysine peptides induce lipid intermixing but not fusion between phosphatidic acid‐containing vesicles
Authors: Bondeson Jan , Sundler Roger
Published: July 2002

Pentalysine
Polylysine
Phosphatidic acid
Lipid intermixing
Membrane fusion
Fluorescence study of the RecA‐dependent proteolysis of LexA, the represser of the SOS system in Escherichia coli
Authors: Takahashi Masayuki , Daune Michel , Schnarr Manfred
Published: July 2002

The fluorescence of the LexA protein, the common repressor of the SOS system in Escherichia coli decreases by about 30% upon incubation with the Ree A protein, and its cofactors ATP [or its non‐hydroly sable analogue adenosine‐5'‐O‐(3‐thiotriphosphate), ATPγS] Mg2+ and single‐stranded DNA. In the absence of any one of these elements required for the RecA‐dependent proteolysis of LexA, this fluorescence change was not observed. The final fluorescence change depends only upon the concentration of LexA regardless of that of RecA. The time course of the fluorescence decrease corresponds well with the kinetics of the decrease of intact LexA protein and the increase of its 2 proteolytic fragments as determined by SDS‐polyacrylamide gel electrophoresis. These results allow us to use the fluorescence change as a signal for a detailed kinetic analysis. The velocity of the proteolysis (d[LexA]/dt) is proportional to the concentration of LexA and RecA indicating that the formation of the LexA‐RecA complex is the limiting step.
C‐rasH and ornithine decarboxylase are induced by oestradiol‐17β in the mouse uterine luminal epithelium independently of the proliferative status of the cell
Authors: Cheng Shirley V.Y. , Pollard Jeffrey W.
Published: July 2002

Oestradiol‐17 β (E2) treatment of the ovariectomized mouse results in a synchronised wave of cell proliferation in the uterine luminal epithelium. At the peak of DNA synthesis the mRNA level of the c‐ras
H protooncogene and ornithine decarboxylase were significantly increased. Progesterone treatment completely inhibits the E2 induced wave of DNA synthesis but does not greatly influence the level of these 2 mRNAs. Thus in the uterine luminal epithelium E2 regulates the level of ornithine decarboxylase and c‐ras
H independently of cell proliferation.
Transglutaminase activity and putrescine‐binding capacity in cloned cell lines with different metastatic potential
Authors: Delcros J.G. , Bard S. , Roch A.M. , Quash G. , Poupon M.F. , Korach S.
Published: July 2002

An inverse correlation was found between cellular transglutaminase activity and metastatic potential of four cloned cell lines derived from a primary nickel‐induced rat rhabdomyosarcoma. Cellular transglutaminase activity as assessed with endogenous cellular protein or exogenous methylated casein was greatest in the clone F9‐ which is the least metastasizing. When the putrescine‐binding capacity of one cellular derived protein ‐ fibronectin ‐ was examined with exogenous transglutaminase, it was found that the fibronectin derived from the clone F9‐ showed the lowest binding capacity compared with those from the other clones. However, when the overall binding capacity of cellular proteins from each cell line was examined no differences could be detected. The results are discussed in the light of the well‐known role of fibronectin in cellular adhesion.
Reversible disc‐to‐vesicle transition of melittin‐DPPC complexes triggered by the phospholipid acyl chain melting
Authors: Dufourc Erick J. , Faucon Jean-François , Fourche Georges , Dufourcq Jean , Gulik-Krzywicki Tadek , le Maire Marc
Published: July 2002

Melittin
Phospholipid membrane
Disc‐to‐vesicle transition
Chain melting
NMR
Freeze‐fracture
Quasi‐elastic light scattering
Cell surface involvement in cancer metastasis: an NMR study
Authors: Holmes Kerry T. , Williams Philip G. , May George L. , Gregory Patricia , Wright Lesley C. , Dyne Marlen , Mountford Carolyn E.
Published: July 2002

NMR spectroscopy is one of the few techniques which has the sensitivity to detect subtle changes to the surface chemistry of cells. It has previously been demonstrated that high resolution 1H NMR methods can distinguish tumour cells with the capacity to metastasise and this information appears to arise from a type of proteolipid in or attached to the plasma membrane. Here we report that the 1H NMR signal, which we have used to identify metastatic cells in rat tumours, is significantly reduced in intensity after cultured cells are treated with trypsin/EDTA. The long T
2 relaxation value (⪢ 350 ms) observed in metastatic cells is absent after enzyme treatment. 2D scalar correlated NMR (COSY) spectra of these treated cells show that a cross peak normally associated with malignancy and metastatic disease is markedly reduced. These findings indicate that the plasma membrane lipid particle which generates the high resolution spectrum is directly affected by trypsin/EDTA. Alterations to the cell surface properties were also demonstrated in vivo since reduced numbers of metastases were observed in animals injected with enzyme‐treated cells. The correlation between the absence of a long T
2 relaxation value and the diminished numbers of metastases in animals suggests that the plasma membrane particle is involved in the metastatic process.
The molecular defect of albumin Tagliacozzo: 313 Lys → Asn
Authors: Galliano M. , Minchiotti L. , Iadarola P. , Stoppini M. , Ferri G. , Castellani A.A.
Published: July 2002

Albumin Tagliacozzo is a fast‐moving genetic variant of human serum albumin found in 19 unrelated families. The protein was isolated from the serum of a heterozygous healthy subject. Analysis of CNBr fragments by isoelectric focusing allowed us to localize the mutation to CNBr fragment IV (residues 299–329). This fragment was isolated on a preparative scale and subjected to tryptic digestion. Sequential analysis of the abnormal tryptic peptide, purified by RP‐HPLC, revealed the variant was caused by 313 Lys → Asn substitution, probably due to a point mutation in the structural gene. The lack of a lysine residue accounts for the electrophoretic behavior of albumin Tagliacozzo.
Absence of structural homology between sup1 and sup2 genes of yeast Saccharomyces cerevisiae and identification of their transcripts
Authors: Surguchov Andrei P. , Telkov Miroslav V. , Smirnov Vladimir N.
Published: July 2002

The results of Southern blotting demonstrate that sup2 is a unique gene in Saccharomyces cerevisiae that does not possess homologous sequences in the yeast genome. The direct hybridization of DNA fragments, containing cloned sup1 and sup2 genes, did not reveal any structural homology between these two genes. By Northern blotting analysis the sizes of the transcripts were determined to be 1.6 kb for sup1 gene and 2.5 and 1.4kb for sup2 gene. Experiments with RNA isolated from yeast mutant with impaired splicing demonstrated that sup1 and sup2 genes do not contain introns.
Intron‐dependent evolution: Preferred types of exons and introns
Authors: Patthy László
Published: July 2002

Exon insertions and exon duplications, two major mechanisms of exon shuffling, are shown to involve modules that have introns of the same phase class at both their 5′‐ and 3′‐ends. At the sites of intronic recombinations exon insertions and duplications create new introns which belong to the same phase class as the recipient introns. As a consequence of repeated exon insertions and exon duplications introns of a single phase class predominate in the resulting genes, i.e. gene assembly by exon shuffling is reflected both by this nonrandom intron phase usage and by the correlation between the domain organization of the proteins and exon‐intron organization of their genes. Genes that appeared before the eukaryote‐prokaryote split do not show these diagnostic signs of exon shuffling. Since ancestral introns (e.g. self‐splicing introns) did not favour intronic recombination, exon shuffling may not have been significant in the early part of protein evolution.