bluuebunny/crossref_metadata_2025 huggingface dataset:
CURRENT STATE AND DEVELOPMENT OF THE CITY PARK IN SKOPJE
Authors: Rizovska Atanasovska Jasminka , Apostolovska Iskra , Velkovski Nikolčo , Andonovski Vlatko , Penčić Divna
Published: May 2020

The City Park in Skopje was established in the early 20th century. There are not many historical dataabout its establishment. Only modest documentation could be found, for the period between the twoworld wars.At the beginning of the 20th century in Skopje a couple of avenues and green areas have been built. Thebigger green area was the one on the location where today’s City Park is built. It was called “Islahane”,after the craft school around which it was established. Its establishment is connected with Hafiz MehmedPasha and the period of Ottomans domination in Macedonia. Built in 1905, it spread out over 16 000m2 and was organized in a classical, geometric style, with trees, shrubs, floral elements and pathways.It was founded on where today’s City Park is located.Through the years it has changed until it got today’s dimensions and borders. The biggest change inits structure was made in the ‘70s of the 20th century when the basic main project for the City Parkwas made. In the last ten years intensive work on its reconstruction has been done, so there is morerelevant data for the Park for this recent period of time.Besides its establishment, this paper presents the current state of the Park, its main characteristics andfunctions. It gives a review of the vegetation and other park elements, as well the state of its overallarea and the changes that have occurred to date.
VELIČINA I VARIJABILITET DEBLJINSKOG PRIRASTA STABALA JELE NA PLANINI BORJA
Authors: Jović Goran , Dukić Vojislav , Stajić Branko , Petrović Danijela
Published: May 2020

Veličina i varijabilitet debljinskog prirasta stabala jele analiziran je za područje Borja planine, u čistimsastojinama jele i u mješovitim sastojinama jele i bukve. Prosječna veličina tekućeg debljinskog prirastastabala jele u čistim sastojinama iznosi 2,62 mm, a u mješovitim sastojinama iznosi 2,40 mm. Varijabilnostdebljinskog prirasta, izražena koeficijentom varijacije, u čistim sastojinama je 63% a u mješovitimsastojinama 75%, odnosno, kada je u pitanju debljinski prirast stabala, može se konstatovati da su homogeniječiste sastojine. Sa opadanjem vitalnosti i biološkog položaja stabala značajno se smanjujedebljinski prirast.
James Stewart and the Changing Face of the Confederate in Mid-Twentieth Century Hollywood Cinema
Authors: Templeton Peter
Published: May 2020

Hollywood cinema offers multifaceted perspectives of the south and the southerner, guided as much by the time of production as by the personnel working on individual movies. This article will focus specifically on two films, fifteen years apart, featuring the same leading actor–James Stewart–in two similar yet distinct portrayals of southerners. The similarities and divergences between the protagonists of Winchester ’73 (1950) and Shenandoah (1965) allow us to explore (via a close reading of each text) specifically how the Confederate rebel was constructed for a national audience in the mid-twentieth century, and how that changed across a contested period that saw wide-ranging events in the battle for Civil Rights. Finally, the article shows how debts and divergences from the nineteenth century logics of white supremacy and secessionism factor into particular Hollywood discourses about geography, whiteness, and masculinity and retain an ongoing relevance in the current, fraught political climate.
Protecting the spirit of the American South: Representations of New Orleans Culture in Contemporary Children’s Picture Books
Authors: Klęczaj-Siara Ewa
Published: May 2020

This article explores selected aspects of southern culture as presented in contemporary children’s picture books. It analyzes children’s stories which celebrate New Orleans’ residents and their traditions. Unlike many scholars who point to the end of the New Orleans spirit due to recent economic and demographic changes, children’s authors perceive the culture as a resource which regenerates the city. By means of writing for children they keep the city’s distinct black culture from disappearing.

The aim of this article is to examine to what extent the spirit of the South has survived in the minds of contemporary authors and artists addressing young generations of readers. It discusses the presence of such cultural elements as jazz music, body movement and the ritual of parading in selected children’s picture books set in New Orleans. Among others, it analyzes such titles as Freedom in Congo Square (2016) by C. Weatherford, and Trombone Shortly (2015) and The 5 O’ Clock Band (2018) by Troy Andrews. The article focuses on the interaction between the verbal and the visual elements of the books, and the ways they convey the meaning of the stories.
Wnt/β-catenin signaling is an evolutionarily conserved determinant of chordate dorsal organizer
Authors: Kozmikova Iryna , Kozmik Zbynek
Published: May 2020

Deciphering the mechanisms of axis formation in amphioxus is a key step to understanding the evolution of chordate body plan. The current view is that Nodal signaling is the only factor promoting the dorsal axis specification in the amphioxus, whereas Wnt/β-catenin signaling plays no role in this process. Here, we re-examined the role of Wnt/βcatenin signaling in the dorsal/ventral patterning of amphioxus embryo. We demonstrated that the spatial activity of Wnt/β-catenin signaling is located in presumptive dorsal cells from cleavage to gastrula stage, and provided functional evidence that Wnt/β-catenin signaling is necessary for the specification of dorsal cell fate in a stage-dependent manner. Microinjection of Wnt8 and Wnt11 mRNA induced ectopic dorsal axis in neurulae and larvae. Finally, we demonstrated that Nodal and Wnt/β-catenin signaling cooperate to promote the dorsal-specific gene expression in amphioxus gastrula. Our study reveals high evolutionary conservation of dorsal organizer formation in the chordate lineage.
How Trainees Finance Their Medical Education: Implications of Higher Education Act Reform
Authors: Scheckel Caleb J. , Richards Jesse R. , Newman Jessica R. , Fangman Ben D. , Poole Kenneth G.
Published: May 2020

Context

The Public Service Loan Forgiveness (PSLF) program is among several repayment programs currently available for recipients of federal student loans. Medical education debt has continued to expand at a rapid pace in the decade since PSLF was created. Proposed changes to the Higher Education Act would substantially transform how future medical trainees finance and repay medical education debt.

Objective

To better understand relationships between debt and personal stress, as well as between repayment- and forgiveness-program use, in the context of competing legislation.

Methods

Surveys were sent to all Accreditation Council for Graduate Medical Education−accredited internal medicine residency programs (osteopathic and allopathic).

Results

From a potential pool of 579 residents, data were obtained from 403 unique respondents (response rate, 69.6%) at 12 residency programs, for a program response rate of 2.2%. Of these respondents, 290 (71.9%) completed the demographic portion of the survey. Median education debt was $225,000. Residents with the top quartile of debt burden were more likely to use PSLF (odds ratio [OR], 3.27; P=.02), more likely to enter loan forbearance (OR, 2.14; P=.03), and indicated a higher level of stress (OR, 5.94; P<.001) compared with those in the second and third quartiles.

Conclusion

Proposed legislative changes to the Higher Education Act would scale back loan repayment options and also eliminate PSLF for future borrowers. Our data suggest that higher debt burdens are associated with increased debt-related stress. Given program popularity and growing use, along with growing concerns of physician burnout, policy makers should weigh the potential downstream effects of policy change on prospective future physicians.
Empathy in Medicine Self and Other in Medical Education: Initial Emotional Intelligence Trend Analysis Widens the Lens Around Empathy and Burnout
Authors: Singer-Chang Gail , Dong Fanglong , Seffinger Michael , Nevins Natalie , Blumer Janice , Musharbash Helen , Helf Scott
Published: May 2020

Context

Integral to emotional intelligence (EI), empathy is frequently studied in medical students. While important, given the implications for patient safety and physician well-being, traits such as self-regard may also affect physician efficacy. Emotional intelligence offers a holistic framework from which to study empathy, allowing it to be explored with coexisting traits and offering opportunities to identify related risk factors.

Objective

To identify trends in osteopathic medical student EI to help mitigate burnout, with specific attention to empathy and self-regard.

Methods

Eight hundred eighty-five students at Western University of Health Sciences College of Osteopathic Medicine of the Pacific from classes 2014-2016 were offered the Emotional Quotient Inventory 2.0 (EQ-i) at the start of school, completion of their second year, and at graduation. Participants completed all 3 inventories, yielding a response rate of 16.3%. Repeated measurement analysis of variance analyses were conducted using SAS software for Windows version 9.3.

Results

A total of 144 students participated. The total EI score shifted from mean (SD) 100.2 (12.4) at baseline to 96.1 (12.8) midway to 96.8 (13.3) at graduation (P=.0161) with significant decreases between baseline and midway (P<.001) and baseline and final administrations (P<.001). Empathy declined from 103 (13.1) to 99.9 (12.7) to 99.6 (12.6) (P=.0481) with significant decreases between baseline and midway (P<.001) and baseline and final administrations (P<.001). Self-regard declined from 98.6 (14.1) to 95.8 (15.1) to 95.5 (14.7) (P=.135) with significant decreases between baseline and midway (P=.0021) and baseline and final administrations (P<.001).

Conclusion

This study's findings support further investigation of potential roles played by EI, empathy, and self-regard in physician burnout.
An improved similarity-based approach to predicting and mapping soil organic carbon and soil total nitrogen in a coastal region of northeastern China
Authors: Wang Shuai , Adhikari Kabindra , Zhuang Qianlai , Yang Zijiao , Jin Xinxin , Wang Qiubing , Bian Zhenxing
Published: May 2020

Soil organic carbon (SOC) and soil total nitrogen (STN) are major soil indicators for soil quality and fertility. Accurate mapping SOC and STN in soils would help both managed and natural soils and ecosystem management. This study developed an improved similarity-based approach (ISA) to predicting and mapping topsoil (0–20 cm soil depth) SOC and STN in a coastal region of northeastern China. Six environmental variables including elevation, slope gradient, topographic wetness index, the mean annual temperature, the mean annual temperature, and normalized difference vegetation index were used as predictors. Soil survey data in 2012 was designed based on the clustering of the study area into six climatic vegetation landscape units. In each landscape unit, 20–25 sampling points were determined at different landform positions considering local climate, soil type, elevation and other environmental factors, and finally 126 sampling points were obtained. Soil sampling from the depth of 0–20 cm were used for model prediction and validation. The ISA model performance was compared with the geographically weighted regression (GWR), regression kriging (RK), boosted regression trees (BRT) considering mean absolute prediction error (MAE), root mean square error (RMSE), coefficient of determination (R2), and maximum relative difference (RD) indices. We found that the ISA method performed best with the highest R2and lowest MAE, RMSE compared to GWR, RK, and BRT methods. The ISA method could explain 76% and 83% of the total SOC and STN variability, respectively, 12–40% higher than other models in the study area. Elevation had the largest influence on SOC and STN distribution. We conclude that the developed ISA model is robust and effective in mapping SOC and STN, particularly in the areas with complex vegetation-landscape when limited samples are available. The method needs to be tested for other regions in our future research.
Kinetic modeling in physiology
Authors: Berman Mones
Published: July 2002

References are included to some of the author's own publications in which these matters are discussed in detail.
Incorporation of fatty acids into the outer and inner membranes of isolated rat liver mitochondria
Authors: Nachbaur J. , Colbeau A. , Vignais P.M.
Published: July 2002

Acyl‐CoA: phospholipid acyl‐transferase activity as well as phospholipase A activity were detected in inner and outer membrane preparations from rat liver mitochondria. Both enzyme systems have an optimum pH around 8 and act preferentially on phosphatidylethanolamine. While phospholipase A activity is much lower in the inner membrane than in the outer membrane of mitochondria the reverse is true for the incorporation of (14C)‐oleic acid into endogenous phosphatidylethanolamine. These results bring an indirect evidence that the inner membrane per se possesses a phospholipase A activity.
Proprietes de nucleoles debarrasses de chromatine perinucleolaire, isoles en milieu MgCl2 a haute force ionique a partir de cellules d'hepatome ascitique de rat
Authors: Martin-Prevel C. , Zalta J.P.
Published: July 2002

A method is devised for isolation of pure nucleoli, devoid of perinucleolar chromatin, from rat hepatoma in a medium of high ionic strength (I = 1, MgCl2 = 0.33 M).
Reactive derivative of adenosine‐5′‐triphosphate formed by irradiation of ATP γ‐p‐azidoanilide
Authors: Badashkeyeva A.G. , Gall T.S. , Efimova E.V. , Knorre D.G. , Lebedev A.V. , Mysina S.D.
Published: July 2002

UV and 1H NMR spectra changes demonstrate that p‐azidoanilides of ATP, ITP, pyrophosphate after irradiation at 313 nm, transform to similar reactive intermediates. The latter react readily with morpholine, iso‐propylamine, tert‐butylamine, imidazole, mercaptoethanol the reactivity being qualitatively correlated with nucleophilicity. By analogy with the transformation of p‐azidoanilide, it is concluded that the reactive intermediate is the respective derivative of quinone diimine. Photoaffinity labelling of proteins with p‐azidoanilide derivatives may proceed as the reaction of the nucleophilic centers of proteins with this quinone diimine derivative, rather than as a direct attack by a nitrene biradical.
Studies of the structure of bacteriophage λ cro protein in solution
Authors: Bolotina I.A. , Kurochkin A.V. , Kirpichnikov M.P.
Published: July 2002

The secondary and tertiary structures of bacteriophage cro protein were studied by circular dichroism. The pH dependence of this structure was investigated; cro protein is stable over pH 4.5–10.5. At these pH‐values cro protein contains ≈35% α‐helix, ≈20% antiparallel β‐structure and ≈15% β‐turn, while the remaining part of the protein molecule is in the irregular state. The secondary and tertiary structures of the protein are modified abruptly at more acid and more alkaline pH‐values. The curves characterizing the secondary and tertiary structures of the protein are symbatic. The effect of Gu—HCl on the secondary and tertiary structures of cro protein at 22°C and pH 7.2 was studied also. The conformational transition occurs within 0.6–1.9 M Gu—HCl. The changes in the secondary and tertiary structures of the protein have a symbatic character. Thermal denaturation of cro protein was examined. A possible mechanism of the protein denaturation is discussed.
Succinate thiokinase from Thermus aquaticus and Halobacterium salinarium
Authors: Weitzman P.D.J. , Kinghorn Helen A.
Published: July 2002

Both citrate synthase and succinate thiokinase occur in either a ‘large’ or ‘small’ form. The ‘large’ forms of these two enzymes have been found only in Gram‐negative bacteria, whereas Gram‐positive bacteria and eukaryotes contain the ‘small’ forms of the two. Hitherto, naturally‐occurring organisms have only been found to contain either both ‘large’ or both ‘small’ forms. The bacteria Thermus aquaticus and Halobacterium salinarium produce ‘small’ citrate synthases. In the case of the Gram‐negative organism Thermus aquaticus, this constitutes a clear exception to the general pattern. This work shows that both these bacteria contain ‘large’ succinate thiokinases, thus indicating that organisms do exist which contain mixed types of these two critic acid cycle enzymes.
Kinetic and spectral resolution of cytochrome c‐553 and cytochrome f in the photosynthetic electron‐transfer chain of heterocysts
Authors: Houchins Jeffrey P. , Hawkesford Malcolm J. , Hind Geoffrey
Published: July 2002

Oxidation of cytochrome c‐553 and cytochrome f following single‐turnover flashes was measured in isolated heterocysts. Half‐times of oxidation for these two cytochromes were determined by measuring the rate of bleaching at 554 nm in heterocysts possessing cytochrome c‐553, or in heterocysts in which cytochrome c‐553 was replaced by plastocyanin. Flash‐induced difference spectra demonstrate that a fast bleaching (t
0.5 = 20–35 μs) corresponds to the oxidation of cytochrome c‐553, and a slower bleaching (t
0.5 = 87 μs) corresponds to the oxidation of cytochrome f.
A new system for ATP‐metric immunoanalysis
Authors: Grachev M.A. , Dobrikov M.I. , Knorre V.D. , Pressman E.K. , Roschke V.V. , Shishkin G.V.
Published: July 2002

Treatment of amino‐group‐containing antigens with adenosine‐5′‐trimetaphosphate results in their chemical modification by ‐pppA residues. An immunoanalytical system is proposed based upon competition of these ATP‐labelled antigens with those of the sample for immobilized antibodies. Mild acidic treatment of complexes of ATP‐labelled antigens with immobilized antibodies results in quantitative liberation of intact ATP. The latter may be determined by the ultrosensitive bioluminescent techniques based upon emission of light with firefly luciferase. The validity of the system has been studied with two clinically important antigens, thyroxine and myoglobin.
Crosslinking of tropomyosin to myosin subfragment‐1 in reconstituted rabbit skeletal thin filaments
Authors: Tao Terence , Lamkin Mark
Published: July 2002

Rabbit skeletal tropomyosin was labeled with the bifunctional photoactivatable crosslinker N‐succinimidyl‐6‐(4′‐azido‐2′‐nitrophenylamino)hexanoate. After irradiating the rigor complex composed of myosin subfragment‐1, crosslinker‐labeled tropomyosin, and F‐actin, a crosslinked product was formed. This product was identified as a 1:1 adduct of tropomyosin and subfragment‐1. This finding is in support of recent structural studies which suggest that tropomyosin and subfragment‐1 are in close proximity to each other, and may be relevant to the mechanism of thin filament regulation.
Antibodies to guanosine
Authors: Iswari S. , Jacob T.M.
Published: July 2002

Bovine serum albumin conjugates of guanosine prepared by the periodate method was used as immunogen to elicit guanosine antibodies in rabbits. The specificities of the antibodies were studied by the inhibition of their binding to [3H]Gox‐red, [32P]DNA and [3H]RNA by related non‐radioactive compounds. A population of antibodies is specific to Gox‐red with an average association constant of around 107M−1 at 4°C. There are a population of antibodies which bind to [32P]ssDNA and [3H]RNA specifically at guanosine residues. RNA binding antibodies were separated into two populations by affinity chromatography.
Diamide blocks H+ conductance in mitochondrial H+‐ATPase by oxidizing FB dithiol
Authors: Huang Youguo , Pringle Michael J. , Rao Sanadi D.
Published: July 2002

Effects of diamide on proton conductance of electron transport particles (ETPH), purified H+‐ATPase (F1–F0), F0 of the H+‐ATPase from beef heart mitochondria and binding of cadmium (109Cd) to the H+‐ATPase have been examined in the present paper. When ETPH and purified H+‐ATPase are treated with 1 mM diamide, ATP‐dependent generation of membrane potential, monitored by the absorbance change produced by the redistribution of oxonol VI, is consistantly inhibited. Diamide also blocks passive H+ conductance driven by a K+ diffusion potential in the membrane sector, F0 of H+‐ATPase. Furthermore, diamide treatment drastically reduces the binding of 109Cd2+ to H+‐ATPase, showing competition for the FB dithiol group.
Differences in processing of cholesterol between rat liver endothelial cells and rat peritoneal macrophages
Authors: Nagelkerke J.Fred , Bakkeren Hille F. , van Berke Theo J.C.
Published: July 2002

Isolated rat liver endothelial cells and rat peritoneal macrophages were incubated with [3H]cholesteryl oleate labeled acetylated LDL in the presence of[14]oleate in order to compare the fate of cholesteryl esters introduced into the cells by a so‐called atherogenic lipoprotein. It was found that 5‐times more [3H]cholesteryl oleate became associated with the endothelial cells per mg cell protein than with the macrophages. Hydrolysis of the cholesteryl esters proceeded in both cell types at a similar rate. In macrophages, however, the cholesterol formed is re‐esterified at a 5‐fold higher rate than in the liver endothelial cells. It is concluded that the cholesteryl esters introduced into the liver endothelial cells by acetylated LDL are rapidly hydrolysed and only to a very limited extent reconverted to cholesteryl esters, which contrasts the fate of this substrate with peritoneal macrophages. This property may allow the endothelial liver cells to function as a proper protection system against circulating atherogenic lipoproteins.
Vasopressin inhibits cyclic AMP accumulation and adenylate cyclase activity in cerebral preparations
Authors: Newman Michael E.
Published: July 2002

Arginine‐vasopressin (AVP) and lysine vasopressin (LVP) elicited a dose‐dependent inhibition of noradrenaline‐sensitive cyclic AMP accumulation in rat cerebral cortical slices, and of forskolin‐stimulated adenylate cyclase activity in a rat cerebral cortical membrane preparation. In both cases LVP was more potent than AVP, and exerted half‐maximal effects at concentrations similar to those found effective in binding studies on rat hippocampal membranes. In hippocampal slices, AVP did not affect, cyclic AMP accumulation at low concentrations but potentiated the effect of noradrenaline at higher concentrations. In caudate membranes, AVP inhibited dopamine‐stimulated adenylate cyclase with a similar dose‐dependency to that seen for forskolin activation in cortex membranes.
Purification of antineoplastic factor from eggs of a sea hare
Authors: Yamazaki Masatoshi , Kisugi Jun , Kimura Katsuya , Kamiya Hisao , Mizuno Den'ichi
Published: July 2002

An antineoplastic factor inducing tumor lysis was purified to apparent homogeneity from the supernatant of a homogenate of eggs of the sea hare Aplysia kwodai. On gel filtration, the purified substance gave a single band of material of 250 kDa containing 3 different subunits and this band coincided with cytolytic activity. The purified factor was half‐maximally active at 10–60 ng protein/ml and lysed all tumor cells tested, but not normal cells. Antineoplastic factor
Tumor lysis
Sea hare Aplysia Cytolysis
Lack of inhibition of thrombin‐induced rise in intracellular Ca2+ levels and 5‐hydroxytryptamine secretion by 1‐oleoyl‐2‐acetylglycerol in human platelets
Authors: Krishnamurthi Sushila , Joseph Sunil K. , Kakkar Vijay V.
Published: July 2002

The effect of 1‐oleoyl‐2‐acetylglycerol (OAG) on the thrombin‐induced rise in intracellular Ca2+ levels ([Ca2+]i) and 5‐hydroxy[14C]tryptamine ([14C]5HT) secretion was studied. In washed human platelets prelabelled with [14C]5HT and quin 2, OAG (10–50 ) induced no significant aggregation, [14C]5HT secretion or rise in [Ca2+]i in the presence or absence of fibrinogen. However, addition of OAG (10–50 ) 10 s to 5 min before or 10–60 s after addition of threshold concentrations of thrombin ( < 0.03 ) resulted in a significant potentiation of aggregation and [14C]5HT secretion without any effect on the thrombin‐induced rise in [Ca2+]i. Both EGTA, which abolished the latter and creatine phosphate/creatine phosphokinase, the ADP scavenger, totally inhibited the aggregation but only partially reduced [14C]5HT secretion in response to thrombin plus OAG. At higher concentrations of thrombin, neither the rise in [Ca2+]i nor the extent of [14C]5HT secretion was significantly altered by OAG addition. The results demonstrate that, unlike phorbol esters, OAG has no inhibitory effect on thrombin‐induced [Ca2+]i mobilisation but can synergize with low concentrations of thrombin in potentiating [14C]5HT secretion even at basal [Ca2+]i.
Structure of protein‐deficient 50 S ribosomal subunits
Authors: Selivanova O.M. , Gongadze G.M. , Gudkov A.T. , Vasiliev V.D.
Published: July 2002

50 S ribosomal subunit derivatives without the 5 S RNA‐protein complex obtained either by splitting with EDTA or by reconstitution from the 23 S RNA and proteins have been studied by electron microscopy. Removal of the 5 S RNA‐protein complex is shown to affect neither the overall morphology of the larger ribosomal subunit nor the mode of its association with the small subunit.
Transient and intramembrane trapping of pumped protons in thylakoids
Authors: Polle Andrea , Junge Wolfgang
Published: July 2002

We measured flash‐induced rapid proton release into the lumen of thylakoids. We found that the proton‐trapping domains which were inducible by low concentrations of gramicidin and at alkaline pH [e.g. (1983) Biochim.Biophys.Acta 723, 294‐307] were each not restricted to a particular photosystem II complex. Instead, they were delocalized. Oxidizing conditions increased the buffering capacity of the domains from approx. 5 H+ per photosystem II more than 2‐fold by shifting the pK towards acidity.
Acid phosphatases bind to the main high density lipoprotein apolipoprotein A‐I
Authors: Vihko P. , Wahlberg L. , Ehnholm C. , Lukka M. , Vihko R.
Published: July 2002

The serum protein binding secretory prostatic acid phosphatase (PAP) and lysosomal placental acid phosphatase (LAP) was purified using affinity chromatography on gels containing immobilized acid phosphatases. The protein, which could be eluted from these enzyme affinity gels only with 0.05 HCl (pH 2.0), was shown to be apolipoprotein A‐I (apo A‐I), the main structural protein of high density lipoprotein (HDL).
Pertussis toxin alters the growth characteristics of Swiss 3T3 cells
Authors: Hildebrandt John D. , Stolzenberg Ethan , Graves Jeanine
Published: July 2002

G‐protein
Cell growth
Pertussis toxin
Cell culture
Growth inhibition
cyclic AMP
Bradykinin inhibits potassium (M) currents in N1E‐ 115 neuroblastoma cells Responses resemble those in NG108‐15 neuroblastoma x glioma hybrid cells
Authors: Higashida Haruhiro , Brown David A.
Published: July 2002

Application of bradykinin to voltage‐clamped N1E‐115 mouse neuroblastoma cells evoked sequential outward and inward membrane currents, accompanied by an increase and decrease of membrane conductance, respectively. Methacholine produced an inward current with a decreased conductance. The outward current response to bradykinin was imitated by intracellular inositol 1,4,5‐trisphosphate (IP3). Bath application of phorbol dibutyrate induced an inward current and potentiated the response to IP3. We conclude that the response of these cells to bradykinin is identical to that of NG108‐15 hybrid cells, and therefore may be attributed to the dual effects of inositol trisphosphate and diacylglycerol formed by hydrolysis of phosphatidylinositide.
Comparative EPR studies on the nitrite reductases from Escherichia coli and Wolinella succinogenes
Authors: Liu M.-C. , Liu M.-Y. , Payne W.J. , Peck H.D. , Le Gall J. , DerVartanian D.V.
Published: July 2002

Hexaheme nitrite reductases purified to homogeneity from Escherichia coli K‐12 and Wolinella succinogenes were studied by low‐temperature EPR spectroscopy. In their isolated states, the two enzymes revealed nearly identical EPR spectra when measured at 12 K. Both high‐spin and low‐spin ferric heme EPR resonances with g values of 9.7, 3.7, 2.9, 2.3 and 1.5 were observed. These signals disappeared upon reduction by dithionite. Reaction of reduced enzyme with nitrite resulted in the formation of ferrous heme‐NO complexes with distinct EPR spectral characteristics. The heme‐NO complexes formed with the two enzymes differed, however, in g values and line‐shapes. When reacted with hydroxylamine, reduced enzymes also showed the formation of ferrous heme‐NO complexes. These results suggested the involvement of an enzyme‐bound NO intermediate during the six‐electron reduction of nitrite to ammonia catalyzed by these two hexaheme nitrite reductases. Heme proteins that can either expose bound NO to reduction or release it are significant components of both assimilatory and dissimilatory metabolisms of nitrate. The different ferrous heme‐NO complexes detected for the two enzymes indicated, nevertheless, their subtle variation in heme reactivity during the reduction reaction.
Nucleosomal repeat length in active and inactive genes
Authors: De Ambrosis Alessandro , Ferrari Nicoletta , Bonassi Stefano , Vidali Giorgio
Published: July 2002

Nucleosomal repeat lengths of total chromatin, H4 histone and β‐DR genes have been measured in logarithmically growing HeLa cells. We have detected significant differences in nucleosomal spacing between inactive chromatin and chromatin regions actively engaged in transcription. These differences are also maintained in metaphase chromosomes at times when transcription ceases although a shortening in nucleosomal repeat length is observed in active and inactive chromatin. These observations support a model where DNA‐core histone interactions are temporarily altered to allow selective remodelling of chromatin organization.
Evidence for a single glycan moiety in rabbit serum transferrin and location of the glycan within the polypeptide chain
Authors: Evans Robert W. , Aitken Alastair , Patel Kokila J.
Published: July 2002

The sequential removal of N‐acetylneuraminic acid from rabbit serum transferrin has been followed by urea‐polyacryl‐amide gel electrophoresis. The electrophoretic pattern is consistent with the presence of a single biantennary glycan chain. From the amino acid sequence of the carbohydrate‐containing cyanogen bromide fragment we have shown that the glycan is attached to an asparaginyl side chain at a position equivalent to residue 491 in the sequence of human serum transferrin.
High molecular mass type IV collagen‐specific metalloprotease from human carcinoma tissue
Authors: Tsuda Michio , Yamagishi Yumi , Katsunuma Tsunehiko
Published: July 2002

A protease degrading type IV collagen was purified more than 8000‐fold from human stomach carcinoma tissue. This protease degraded type IV collagen, while type I, II, III and V collagen, laminin, fibronectin, casein, albumin and hemoglobin were not affected. This enzyme had a pH optimum of pH 7.0–8.0 and was inhibited completely by EDTA and o‐phenanthroline, but not by seryl, thiol and carboxyl protease inhibitors. Furthermore, the molecular mas of this enzyme was estimated to be 1 MDa by Sepharose 6B column and HPLC‐gel filtration. The molecular mass and substrate specificity of this metalloprotease from human carcinoma tissue indicate it to be a new protease.
Nuclear Overhauser effects in aqueous solution as dynamic probes in short linear peptides
Authors: Nieto J.L. , Jiménez M.A. , Rico M. , Santoro J. , Herranz J.
Published: July 2002

The possibility of obtaining interresidue NOEs from short linear peptides in aqueous solution has been investigated from an experimental point of view using peptides of various lengths (namely GGRA, LHRH and RNase S‐peptide). It is shown that, provided that long (8̃00 ms) NOESY mixing times are used, complete sets of sequential αN NOEs are obtainable. From the intensities and signs of the observed NOEs, the relative mobilities of different parts of the polypeptide chain can be determined.
Monoclonal antibody to human endothelial cell surface internalization and liposome delivery in cell culture
Authors: Trubetskaya O.V. , Trubetskoy V.S. , Domogatsky S.P. , Rudin A.V. , Popov N.V. , Danilov S.M. , Nikolayeva M.N. , Klibanov A.L. , Torchilin V.P.
Published: July 2002

A monoclonal antibody (mAb), E25, is described that binds to the surface of cultured human endothelial cells. Upon binding E25 is rapidly internalized and digested intracellularly. Selective liposome targeting to the surface of the cells is performed using a biotinylated E25 antibody and an avidin‐biotin system. Up to 30% of the cell‐adherent liposomal lipid is internalized.
The effects of vascular smooth muscle caldesmon on force production by ‘desensitised’ skeletal muscle fibres
Authors: Taggart Michael J. , Marston Steven B.
Published: July 2002

Smooth muscle caldesmon inhibits actomyosin MgATPase in the absence of Ca2+ and is the key regulatory component of Ca2+‐regulated thin filaments. We now show that caldesmon can affect contractility as well. Glycerinated skeletal muscle fibres were treated so as to produce substantial contractions without Ca2+ as an activator. Addition of caldesmon caused reductions in force in a concentration‐ and time‐dependent manner. Perfusion with caldesmon concentrations for < 5 min gave up to 48% reduction in isometric tension with a half‐maximal effect at 1.5 μm caldesmon. Perfusion with 15 μM caldesmon for 30 min gave an irreversible tension drop.
Sub‐second turnover of transducin GTPase in bovine rod outer segments A light scattering study
Authors: Wagner Rafael , Ryba Nicholas , Uhl Rainer
Published: July 2002

A fast, regenerative light scattering signal from bovine ROS, the PA‐signal, reflects the light‐induced, transient activation of transducin. Its rate of recovery depends on the number of photolysed rhodopsin molecules, indicating that rhodopsin deactivation and not GTPase activity is rate limiting in our in vitro system. When rhodopsin deactivation is accelerated (in the presence of NH2OH), PA‐signal recovery is also accelerated. A GTPase turnover number of more than 2 s−1 (at 37°C) can be derived from these experiments. This is more than one order of magnitude faster than the GTPase rates so far described in the literature and is rapid enough for a physiological shut‐off mechanism. The fast GTPase is attributed to a highly intact disk stack, which never releases transducin into the free aqueous space.
Radiation inactivation analysis of sarcoplasmic reticulum Ca‐ATPase in membrane‐bound form and in detergent‐solubilized monomeric states
Authors: Andersen Jens P. , Vilsen Bente
Published: July 2002

The sarcoplasmic reticulum Ca‐ATPase was subjected to target size analysis by radiation inactivation in various buffer conditions and after solubilization in monomeric form in non‐ionic detergent and in SDS. The target size was also determined for Ca‐ATPase in bidimensional crystals formed in the presence of decavanadate or lanthanide. The standardization obtained with defined monomers of Ca‐ATPase shows that the target size of Ca‐ATPase in the functional membrane‐bound state may be ascribed to a single peptide chain, possibly with surrounding lipid. Further analysis of the radiation inactivation sizes of various partial reactions of the pump cycle, including phosphorylation and Ca2+ occlusion, indicated much smaller values than the target size pertaining to decomposition of the whole peptide chain. This is consistent with the existence of separate functional domains within a single peptide chain.
Cytisine inhibition of informosome release from wheat embryo nuclei
Authors: Ajtkhozhina N.A. , Ismagulova G.A.
Published: July 2002

We have studied the action of the alkaloid cytisine on protein synthesis of plants. The alkaloid has been shown to have no effect on mRNA translation. At the same time it considerably decreases the release of mRNP particles from nuclei.
Phenobarbital, dexamethasone and benzanthracene induce several cytochrome P450 mRNAs in rat hepatoma cells
Authors: Corcos Laurent , Weiss Mary C.
Published: July 2002

Hepatoma cells derived from the Reuber H35 rat hepatoma express cytochrome P450 enzymes of two major families: polycyclic aromatic hydrocarbon‐inducible forms are found in both differentiated and dedifferentiated cells while phenobarbital (PB)‐inducible forms are found only in differentiated cells. We report here that (i) benzanthracene and PB induce P450 c mRNA in differentiated and dedifferentiated cells and (ii) dexamethasone and PB induce P450 b/e and/or P450 PB1 mRNAs in differentiated cells but not in dedifferentiated cells.
1,2‐Diacylglycerol accumulation in human neutrophils does not correlate with respiratory burst activation
Authors: Koenderman Leo , Tool Anton , Roos Dirk , Verhoeven Arthur J.
Published: July 2002

Measurements of the level of 1,2‐diacylglycerol (1,2‐DG during activation of the respiratory burst of human neutrophils by formyl‐methionyl‐leucyl‐phenylalanine (fMLP in the presence of platelet‐activating factor (PAF or by opsonized particles show that a correlation between accumulation of 1,2‐DG and O2 consumption does not exist. Inhibition of protein kinase C activity with staurosporine before addition of opsonized particles demonstrates that the first phase of the respiratory burst is not inhibited, whereas the second phase, which is accompanied by a rise in the content of 1,2‐DG, is strongly inhibited. This study indicates that accumulation of 1,2‐DG cannot be the sole signal for the initiation of the respiratory burst in human neutrophils.
Stimulation of transcription from different RNA polymerase II promoters by high mobility group proteins 1 and 2
Authors: Tremethick David J. , Molloy Peter L.
Published: July 2002

High mobility group proteins (HMGs) 1 and 2 are shown to stimulate transcription in vitro from a number of RNA polymerase II promoters. Greatest effects were seen on transcription from the SV40 late promoter, then the SV40 early promoter with similar levels of transcription enhancement being seen for the human metallothionein 2A, adenovirus major late and chicken feather keratin promoters. The results indicate that HMGs 1 and 2 act to increase initiation of transcription in vitro and differential effects on the promoters are consistent with their action being in part to enhance the binding or functional activity of promoter‐specific transcription factors.
Photoaffinity cross‐linking of F1ATPase from the thermophilic bacterium PS3 by 3′‐arylazido‐β‐alanyl‐2‐azido ATP
Authors: Schäfer Hans-Jochen , Rathgeber Gabriele , Dose Klaus , Kagawa Yasuo
Published: July 2002

The photoactivatable bifunctional 3′‐arylazido‐β‐alanyl‐2‐azido ATP (2,3′‐DiN3ATP) has been applied to study the localization of the nucleotide‐binding sites of coupling factor 1 (F1ATPase, TF1) from the thermophilic bacterium PS3 by photoaffinity cross‐linking. UV irradiation of TF1 in the presence of 2,3′‐DiN3ATP results in the nucleotide‐dependent formation of various higher molecular mass cross‐links formed by two, three or even four α‐ and/or β‐subunits. The differences observed upon photoaffinity cross‐linking by the bifunctional 2‐azido ATP or 8‐azido ATP analog are discussed. They are probably due to the varied maximal distance between both azido groups, or to the different conformations (anti/syn) of these analogs. The results confirm our suggestion that several (possibly all) nucleotide‐binding sites of F1ATPases are located at the interfaces between α‐ and β‐subunits.
A specific, low Km ADP‐ribose pyrophosphatase from rat liver
Authors: Miró Asunción , Costas María Jesús , García-Díaz Miguel , Hernández María Teresa , Cameselle José Carlos
Published: July 2002

Two rat liver ADP‐ribose pyrophosphatases (ADPRibases) were partially purified. ADPRibase‐I hydrolyzed ADP‐ribose (K
m=0.5 μM) giving AMP as a product, required Mg2+ or, less efficiently, Mn2+ (Ca2+ was not active), its activity changed little between pH 7 and 9, and was specific for ADP‐ribose as it did not hydrolyze ADP‐glucose, NAD+, NADH or diadenosine 5′,5″‐P
1,P

n
‐n‐phosphates (Ap2A, Ap3A). ADPRibase‐II showed similar properties, except that the K
m for ADP‐ribose was 50 μM and may be non‐specific, as the same preparation hydrolyzed ADP‐glucose, NADH and Ap2A. ADPRibase‐I fulfils the requirements of a specific turnover pathway consistent with a cellular role for free ADP‐ribose.
The effect of substrates and inhibitors of cytochrome P‐450 on the NADPH inhibition of the ATP‐dependent, hepatic, microsomal calcium pump
Authors: P. Srivastava  , Chen NengQian , Holtzman Jordan L.
Published: July 2002

In hepatic microsomes one or more isozymes of cytochrome P‐450 inhibits the ATP‐dependent Ca2+ pump. This inhibition is reversible by GSH and appears to be due to a direct oxidation of the pump proteins by the oxygenated cytochrome. To determine which isozyme mediates this inhibiton, we have examined the effect of various substrates and inhibitors on the NADPH inhibition of Ca2+ uptake. We find that aminopyrine, benzphetamine and SKF‐525A reverse this inhibition while a number of other substrates do not. This pattern suggests that a previously unreported isozyme of cytochrome P‐450 mediates the Ca2+ pump inhibition.
Studies on the interaction of C1q,a subcomponent of the first component of complement, with porins from Salmonella minnesota incorporated into artificial membranes
Authors: Latsch Maria , Möllerfeld Jörg , Ringsdorf Helmut , Loos Michael
Published: July 2002

Purified outer membrane proteins (OMP) of Salmonella minnesota, Re‐form, were incorporated into liposomes. These induced in macrophages a chemiluminescence signal identical to that of the intact Re‐form. This signal was abolished by preincubation of porin‐containing liposomes with purified C1q. Incorporation of isolated OMP into black lipid membranes (BLM) resulted in channel‐formation which could not be inhibited by isolated C1q. Additionally, incubation of OMP‐containing liposomes with BLM resulted in pore‐formation within the BLM. This was amplified when lipid A was present within the liposomes. Preincubation of OMP‐containing liposomes with purified C1q abolished pore‐formation within the BLM.
Cluster of point mutations predetermined by a quasipalindromic nucleotide sequence in plasmid pBR322 DNA
Authors: Salganik R.I. , Dianov G.L. , Medvedev O.A.
Published: July 2002

Development of a cluster of point mutations due to the correction of an imperfect hairpin in plasmid DNA was investigated. Plasmid pBR322 DNA containing opposite double‐strand DNA lesions in the region of a quasipalindrome was constructed. For this aim plasmid DNA was cleaved at the BamHI site, and cytosine residues of the sticky ends were modified by O‐methylhydroxylamine. Modified linearized plasmid DNA was ligated and used for transformation of E.coli cells. Tetracycline‐sensitive transformants were selected, and the mutants were characterized by restriction and sequencing analysis. One mutant contained a cluster of point mutations. The distribution of mutations was consistent with the cluster having arisen through correction of the imperfect hairpin formed by the quasipalindrome.
Amplification of the Na+‐ATPase of Streptococcus faecalis at alkaline pH
Authors: Kakinuma Yoshimi , Igarashi Kazuei
Published: July 2002

The Na+‐ATPase activity of Streptococcus faecalis was influenced by the medium pH. Activities of the protonophore‐resistant Na+ extrusion and the KtrII (active K+ uptake by the Na+‐ATPase) were maximal in the cells grown at pH 9.5, and were minimal in those grown at pH 6.O. In the cells grown at pH 7.5, they were moderately observed. The Na+‐stimulated ATPase activity of the cells grown at pH 9.5 was about 4‐fold higher than that of the cells grown at pH 6.O. Thus, amplification of the Na+‐ATPase is remarkable at alkaline pH in this organism, possibly by an increase of the cytoplasmic Na+ level as a signal.
A 36‐kDa mitochondrial protein is responsible for cyanide‐resistant respiration in Hansenula anomala
Authors: Minagawa Nobuko , Sakajo Shigeru , Komiyama Tadazumi , Yoshimoto Akio
Published: July 2002

Antimycin A‐dependent induction of cyanide‐resistant respiration in Hansenula anomala was reversibly blocked by carbonylcyanide‐m‐chlorophenylhydrazone (CCCP). When the cells were pulse‐labeled with [35S]methionine in the presence of both antimycin A and CCCP, the radioactivity was incorporated into a 39 kDa mitochondrial protein. Upon removal of CCCP, this protein was processed into a 36 kDa form. The increase in the 36 kDa protein completely paralleled that in cyanide‐resistant respiration activity, suggesting that the 39 kDa protein is the precursor of the 36 kDa protein, which is responsible for cyanide‐resistant respiration.
Tight ATP and ADP binding in the noncatalytic sites of Escherichia coli F1‐ATPase is not affected by mutation of bulky residues in the ‘glycine‐rich loop’
Authors: Pagan Janet , Senior Alan E.
Published: July 2002

It is shown that ATP dissociates very slowly (k
off< 6.4 × 105 s−1, t

3 h) from the three noncatalytic sites of E. coli F1‐ATPase and that ADP dissociates from these three sites in a homogeneous fashion with k
off = 1.5 × 10−4 s−1 (t

= 1.35 h). Mutagenesis of α‐subunit residues R171 and Q172 in the ‘glycine‐rich loop’ (Homology A) consensus region of the noncatalytic sites was carried out to test the hypothesis that unusually bulky residues at these positions are responsible wholly or partly for the observed tight binding of adenine nucleotides. The mutations αQ172G or αR171S,Q172G had no effects on ATP or ADP binding to or rates of dissociation from F1 noncatalytic sites. K
dATP
and K
dADP
of isolated α‐subunit were weakened by approximately 1 order of magnitude in both mutants. The results suggest that neither residue αR171 nor αQ172 interacts directly with bound nucleotide, and show that the presence of bulky residues per se in the glycine‐rich loop region of F1‐α‐subunit is not responsible for tight binding in the noncatalytic sites.
Identification of haptoglobin as an endogenous inhibitor of prostaglandin H synthase in the cytosol fraction of primary cells from sheep vesicular glands
Authors: Beisembaeva R.U. , Mursagalieva A.T. , Dzhumalieva L.M. , Shaikenov T.E. , Mevkh A.T.
Published: July 2002

It was shown that cytosol of primary sheep vesicular gland cells inhibits peroxidase activity of prostaglandin H synthase (PGHS). The degree of the enzyme inactivation depends on cytosol concentration. It was established that cytosol contains glycoprotein haptoglobin that is one of the cytosol basic components responsible for its property to inhibit PGHS. Haptoglobin is supposed to participate in endogenous regulation of PGHS activity in sheep vesicular glands.
Glycosylation of the murine erythropoietin receptor
Authors: Mayeux P. , Casadevall N. , Muller O. , Lacombe C.
Published: July 2002

Murine erythropoietin‐responsive Rauscher Red 5‐1.5 cells were used to determine the contribution of glycosylation to the size and function of the erythropoietin receptor. The half life of the receptors was determined to be 4 h. The number of receptors was not significantly decreased in cells treated for 48 h with inhibitors of glycosylation (tunicamycin, glucosamine or swainsonine) and their affinity was slightly enhanced in tunicamycin‐ or glucosamine‐treated cells. Erythropoietin was cross‐linked with two proteins of 104 and 86 kDa. Their molecular masses were not significantly reduced in cells treated with the glycosylation inhibitors. When immunoprecipitated cross‐linked receptors were digested with endoglycosidases, the molecular masses of both proteins were only slightly modified giving values of 100 and 82 kDa. Thus we can conclude that the proteins crosslinked to erythropoietin are very weakly glycosylated.