bluuebunny/crossref_metadata_2025 huggingface dataset:
Rasche Bestimmung Geringer Phosphormengen im Ferrovanadin
Authors: Iwantscheff Georg , Meuwsen Alwin
Published: January 2005

Für eine in der Hitze rasche (10 Minuten Dauer) und vollständige Ammoniumphosphormolybdatfällung ist bei Gegenwart von Vanadin folgendes zu beachten:

Die Konzentration des Phosphors sol1 1:l04 nicht wesentlich unterschreiten. Tritt dieser Fall ein — z. B. im Vanadin(V‐) oxyd — so muß vor der Fällung noch eine entsprechende Menge Fremdphosphor als Phosphat zugefugt werden. Damit in der Siedehitze aus dem überschussigen Fällungsreagens keine das Resultat fälschende Molybdänsäurefällung einsetzt, ist für jedes Gramm Ammoniumparamolybdat die Anwesenheit von je 1,5–3g Sulfation geboten.

Die quantitative Ammoniumphosphormolybdatfällung versagt, wenn Spuren Vanadat zugegen sind. Ist jedoch während der Phosphatfällung ständig Hydrazinsulfat vorhanden, welches Vanadat sicher zu Vanadylsalz reduziert, so kann sich der Ammoniumphosphormolybdatniederschlag auch bei Gegenwart von viel Vanadylsalz vollständig und rasch abscheiden. Etwa gleichzeitig gebildetes Molybdänblau wird bei Anwesenheit von Eisen durch die warme Salpetersäure schnell wieder beseitigt, so daß eine schließlich rein gelbe Färbung zustande kommt.

Kleinere Mengen Arsensäure (P : As 7 ≦ 1 : 3) beeinflussen die Phosphorbestimmung nicht, wenn man die (aus ihr durch Hydrazinsulfat) entstandene arsenige Säure mittels bestimmter Mengen Quecksilber (II)‐salz katalytisch daran hindert, wieder in Arsensäure überzugehen.
Über Metallcarbonyle. XLV. Das Rhodium im System der Metallcarbonyle
Authors: Hieber W. , Lagally H.
Published: January 2005

Es konnte die homologe Reihe der Rhodiumdicarbonyl‐monohalogenide, Rh(CO)2Halg (Halg = C1, Br, J), aufgedeckt werden, und zwar durch Einwirkung von Kohlenoxyd auf die Rhodium(III)‐halogenide bei höherer Temperatur und gewöhnlichem oder höherem Druck. Die Verbindungen sind Nichtelektrolyte von typischem Carbonylcharakter; die große Ähnlichkeit ihrer Eigenschaften, wie Flüchtigkeit, Löslichkeit in indifferenten Mitteln, Schmelzpunkt, die sonst bei homologen Carbonylhalogeniden stark abgestuft sind, besonders die anomale Farbabstufung vom tiefroten Chlorid zum gelben Jodid läßt strukturelle Unterschiede vermuten: während dem Chlorid auf Grund von Molekulargewichtsbestimmungen dimere Struktur zukommt, (OC)2RhRh(CO)2, ist das Jodid vielleicht monomer.
Über die Autoxydation des Tricyclohexylbleis und sein Verhalten zu Tetrachlorkohlenstoff
Authors: Hein Fr. , Nebe E. , Reimann W.
Published: January 2005

Es wurde festgestellt, daß die Autoxydation des Tricyclohexylbleis auch in Lösung nur bei geeigneter Belichtung vor sich geht. Die hiernach erforderliche Aktivierung R3Pb → R3Pb* findet durch Na‐Licht nicht statt. Die Kurve der Lichtabsorption des (C6H11)3Pb enthält weder im Sichtbaren noch im Ultraviolett charakteristische Absorptionsmaxima. Dem Gesamtverlauf der Autoxydation entspricht quantitativ praktisch die Formulierung
equation image
Anstatt eines Peroxydes konnte nur (C6H11)3PbOPb (C6H11)3, das in gleicher Weise weiter reagierte, als Zwischenprodukt gefaßt werden.
Über das KURROL'sche Natriummetaphosphat
Authors: Huber Hans , Klumpner Karl
Published: January 2005

Es wird eine neue Methode zur Darstellung des KURROL'schen Salzes beschrieben. Die an diesem Salz beobachteten Eigenschaften weichen in wesentlichen Punkten von den Angaben von PASCAL ab.
Zur Kenntnis des Systems NiTeNiTe2
Authors: Klemm Wilhelm , Fratini Nicola
Published: January 2005

1. Es werden die Fragen erörtert, die bezüglich des Auftretens des NiAs‐, CdJ2‐ und Pyritgitters bzw. des Überganges vom NiAs‐ zum CdJ2‐Typ bei den Chalkogeniden der Übergangselemente auftreten.
Über Ein niederes Aluminiumfluorid
Authors: Klemm Wilhelm , Voss Ernst
Published: January 2005

Bei der Einwirkung von Aluminiummetall auf AlF3 entsteht ein niederes Fluorid der Zusammensetzung (AlF)x. Daneben tritt eine geringe Sublimation von AlF3 selbst ein, die neben der Verflüchtigung des Subfluorids um so stärker in Erscheinung tritt, je niedriger die Temperatur ist. Bei der Kondensation zerfällt das Subfluorid in Metall und Trifluorid.
Über die Herstellung, Reinigung, Verarbeitung und Analyse von Fällungen aus Lösung unter Sauerstoffausschluß
Authors: Rihl S. , Fricke R.
Published: January 2005

Am Beispiel des Fe(OH)2 wurde eine Methodik geschildert, welche folgende Operationen unter vollkommenem Sauerstoffausschluß gestattet: Fällung aus Lösung, Reinigung, Trocknung, Abfüllung und Analyse.
A future for community psychology practice
Authors: Chavis David M.
Published: January 2005

Community psychology has never really looked at its practice as a profession, though many of us as students came to the field with high expectations that we could learn how to make a difference in communities. This article discussed what I think about community psychology practice and how I have tried to approach it.
American psychology, and the needs for transcendence and community
Authors: Sarason Seymour B.
Published: January 2005

In this its centennial year the American Psychological Association has reason to take satisfaction from its past accomplishments. However, as psychologists we know that our view of our history has some self‐serving aspects. There have been some errors of commission and omission. In this paper one of those errors of omission is discussed: the significance of religion, especially of the fundamentalist variety, for understanding the modern psyche. This omission is viewed from a historical perspective in which the relationship between the needs for transcendence and community underwent a fracturing that has had troublesome consequences both for religious and nonreligious people. The nature of those needs are illustrated in the ideas and writings of two people separated by 2500 years: Socrates and B. F. Skinner.
Activity settings as the unit of analysis: A theoretical basis for community intervention and development
Authors: O'Donnell Clifford R. , Tharp Roland G. , Wilson Kathleen
Published: January 2005

Theory, methods, and action develop within context, one of which is the intellectual climate of an era. Community psychology is directly and indirectly interactive with many intellectual currents, such as postmodernism, semiotics, hermeneutics, and dialogism. These ideas are discussed as they impact on community psychology, with an emphasis on the reemergence of meaning as a central condition of psychology and community. Meaning is of key importance to the unifying concept in the transactional theoretical model which is presented. How this model might serve as a conceptual framework for an asset approach to community intervention and development is discussed. Increasingly, it is recognized that the development of theory to guide community research and action is necessary to advance intervention and to realize the potential of community psychology. It is argued that community psychology is positioned by concepts and practice squarely at the point of emerging thought, and can make fuondational contributions to general social science. The next article in this special section illustrates concepts of this model in an early education program and the remaining article illustrates the influence of ecocultural factors.
Early education as community intervention: Assisting an ethnic minority to be ready for school
Authors: Roberts Richard N.
Published: January 2005

An early education program designed for an ethnic minority of Native Hawaiians implemented at the community rather than the individual child level of intervention is described. The program development effort is theory driven and provides an opportunity to investigate the application of neo‐Vygotskian theory to an applied community educational problem. Though not specifically derived from the work of O'Donnell, Tharp, and Wilson (1993), the project reported here shares a common intellectual heritage. This paper demonstrates the parallels between the early education program developed for Hawaiian children and the applicability of the theory presented in the work of O'Donnell et al.
Methodological issues in prevention research: An introduction to the special issue
Authors: Jansen Mary A. , Johnson Elaine M.
Published: January 2005

In recent years increased attention has been directed to prevention research as a means of solving the multitude of complex social and health problems which confront individuals and their societies. Abuse of substances, behavioral dysfunctions, violence, emotional disorders, educational failures, unwanted pregnancies and sexually transmitted diseases are but a few examples of these most difficult problems. As our recognition of the need for sound prevention strategies has grown, so has our sophistication in designing prevention research studies to evaluate the effectiveness of these new strategies. And that sophistication has brought new challenges, some of which are capable of stifling progress because of their complexity. This problem is certain to grow in importance as interventions with multiple components are used more frequently to meet the challenges of the complex social and health problems we face. This special issue evolved out of the recognition that prevention researchers are confronted by a myriad of difficult methodological issues which have inhibited progress in this area. The articles in the issue present innovative methodological solutions designed to overcome these problems so the field can move forward.
Preventing problems in prevention research
Authors: Sechrest Lee B.
Published: January 2005

The design, conduct, and analysis of prevention research efforts present formidable challenges, but as the papers in this volume illustrate, the problems of prevention research are probably not altogether intractable; they simply require the best of our thinking and the firmest of our commitments. The papers included in this issue represent some of the best thinking likely to be available, and, in aggregate, they give reason for some optimism about prevention research. Which is fortunate, because it is by now abundantly clear that treatment of all the assorted personal and social maladies that afflict us individually and as a society, is impossibly intrusive and expensive, even if we were certain we knew what to do, and we are not. Treatment research is only a step or two ahead of prevention research in nearly any field.
Peer telephone dyads: Putting conclusions on hold
Authors: Gottlieb Benjamin H.
Published: January 2005

Conclusion

Through systematic study of intervention trials, which are as carefully crafted and as critically examined as the one reported here, we can gain new insights into ways of intentionally creating the interpersonal and environmental conditions conducive to the expression and acceptance of support. To plan appropriate and acceptable changes in the social ecology, we must develop a theory of the intervention, drawing on both the voluminous generative base of research on social support and on knowledge gained from examination of the particular forces that potentiate and limit exchanges of support in the networks of the intended beneficiaries. In conducting the intervention, careful recordings of the interpersonal transactions that take place and their bearing on the parties' perceptions of the evolving character of the relationship can bring the needed process dimension to emergent theory on social support. And by evaluating the impact of the intervention on a range of proximal and distal outcomes, we can discern more clearly how social support's mechanisms of action confer measurable benefits, particularly those prized by the participants themselves.
Letter to a genetic counselor
Authors: Green Rose
Published: January 2005

The author describes her personal experience terminating a pregnancy after receiving an abnormal amniocentesis result: While still waiting for the results, she and her husband attempted to deny the importance of the pregnancy, an approach which they subsequently regretted. When they received the abnormal result, they found themselves able to make necessary decisions quickly, despite being in shock. It then took some time before they realized what a major loss they had actually suffered. The painful aftermath included accepting emotional responsibility for their decision to abort, as well as explaining that difficult decision to their older children. Thoughts of a possible subsequent pregnancy could not be faced at once. Over time, the author found the support of friends and colleagues, and even of a support group, to be invaluable. All in all, the entire experience was more painful than she would have predicted, and she hopes that this account will prove helpful both to genetic counselors and to other patients who receive abnormal results from prenatal diagnosis. A list of suggested readings is appended.
The future of genetics in public health
Authors: Meaney F. John
Published: January 2005

During the 1980s, we have witnessed an erosion in federal and state funding for the coordination of genetic services in state health departments. As this decade begins, the federal budget for the support of the national genetics program is less than half of the total available in 1980. In addition, priorities in state maternal and child health programs have changed, and genetic services have often received lower rankings aside of programs to improve prenatal care and to address problems such as teenage pregnancy. Clearly we are at a critical point for the future of genetics programs in the public health arena. Fortunately, despite the problems with funding and priority setting, important coalitions have been built during the past decade and continued advances in medical genetics have made it difficult for public health officials to ignore the potential impact of genetic services. Council of Regional Networks for Genetic Services (CORN) and the regional genetic services networks have provided opportunities for interaction and coordination between genetic services providers and public health officials that had not been available to any significant extent. The full potential of these coalitions has yet to be realized, but efforts in data collection, development of national guidelines and standards, and information sharing and networking have already had an influence on state genetic services programs. Continuing research on the genetics of chronic diseases and the influence of discoveries in molecular genetics will undoubtedly broaden the current scope of state public health programs in genetics, which all too often have been limited to newborn screening and administration of grants for genetic services. The regional and national genetic services programs should be strengthened and appropriate training programs should be developed in Schools of Public Health to provide the expertise and leadership that will be needed to guide the future of genetics in public health.
Ethical principles and cultural integrity in health care delivery: Asian ethnocultural perspectives in genetic services
Authors: Wang Vivian , Marsh Frank H.
Published: January 2005

The tradition of Western thought is not always ubiquitous when working within the context of different ethnocultural populations, particularly that of Asian culture, and often poses ethical quandaries for health care professionals engaged in genetic services. For example, understanding the Asian ethnocultural perspective of patient autonomy, informed consent, and nondirective counseling from the Western perspective may be inappropriate and compromise cultural integrity and the delivery of effective genetic services because: (1) A distinction exists between the role of Asian (collective) autonomy vs. Western (individual) autonomy in the decision‐making process. (2) The medical model is complementary to Asian expectations and respect of authority and may result in an uninformed consent to genetic professional's recommendations. (3) Misinterpretations of the normative decision‐making process, misconceptions of normalcy, and the limits of tolerance of nondirective counseling may result in less effective treatment and compliance. Therefore, we suggest that acknowledging the impact of ethnicity and culture on ethical principles as applied in genetic services is essential in the assessment and delivery of ethically and culturally appropriate health care.
Medium‐chain acyl CoA dehydrogenase deficiency: Its relationship to SIDS and the impact on genetic counseling
Authors: McConkie‐Rosell Allyn , Iafolla A. Kimberly
Published: January 2005

Sudden infant death syndrome (SIDS) is defined as the sudden and unexpected death of an apparently healthy infant under 1 year of age. Routine autopsies often provide few clues as to the cause of death and rarely include a biochemical evaluation. Genetic counseling for SIDS can be difficult as recurrence risks vary depending on the age at death and the number of deaths which have occurred in the family. Biochemical disorders may account for up to 5% of SIDS. Of the metabolic disorders known to be involved in SIDS, the most commonly found is medium‐chain acyl CoA dehydrogenase deficiency (MCAD). MCAD is an autosomal recessive disorder of fatty acid oxidation which accounts for up to 1% of SIDS. For some families, the addition of a postmortem biochemical investigation can identify an unsuspected metabolic disorder as the cause of death. Once the diagnosis is established, accurate genetic counseling can then be provided. Metabolic testing of the surviving siblings of victims of sudden death, and the subsequent identification of those due to MCAD can prevent the tragedy of recurrent SIDS in some families. In addition, screening the survivors of an acute life threatening event (ALTE) may also prevent a recurrence.
The challenge of “Healthy People 2000”
Authors: Crocker Allen C.
Published: January 2005

The federal Office of Disease Prevention and Health Promotion (U.S. Public Health Service) has again prepared a compilation of goals and objectives for the health of the Nation's people, applicable to anticipated achievements within the decade ending in the year 2000. This effort involved work groups from numerous federal agencies, testimony in regional hearings from 800 citizens, and enrollment of a consortium of 300 national organizations. The final product, “Healthy People 2000,” was released in September 1990, and contains 298 measurable objectives. Content regarding children, genetic disorders, developmental disabilities, and disabilities in general is less featured and less specific than was hoped for. Ten objectives of relatively direct concern to geneticists are discussed, plus 23 others of interest in the maternal and child health field. On balance, it is suggested that the Healthy People 2000 objectives can be useful and stimulating for workers in genetics, child health care, and disabilities' services. Regrettably, there was no simultaneous proposal of legislation that would provide new federal programs, funding, or assistance to states.
Genetic counseling for deaf adults: Communication/language and cultural considerations
Authors: Israel Jamie , Cunningham Margaret , Thumann Helen , Arnos Kathleen Shaver
Published: January 2005

It has been estimated that at least 50% of congenital or early onset deafness loss has a genetic etiology. Genetic services have traditionally been utilized by hearing parents of deaf children. Deaf adults could also greatly benefit from genetic counseling services. However, many deaf adults do not seek genetic services due in part to the communication/language and cultural differences of this group. Deaf people communicate in various ways including the use of sign language, oral communication, writing, or a combination of these modes. Also, while some deaf individuals are part of the hearing culture, others are part of the Deaf culture which has its own language, values, and traditions. Culturally Deaf individuals do not see themselves as handicapped or disabled. The genetic professional's awareness of the communication/language and cultural needs of this group, as well as their agency's responsibilities under section 504 of the Rehabilitation Act of 1973, may increase the accessibility of genetic services and contribute to the provision of successful genetic counseling for deaf adults.
Continuing education in genetics for Adoption workers in Wisconsin
Authors: Burns Joan K. , Reiser Catherine A.
Published: January 2005

In response to 1982 legislation and 1984 changes in the Wisconsin Adoption Records Laws requiring the collection of a medical‐genetic history at the time of termination of parental rights, a continuing education program in genetics was conducted for adoption workers in 1984 and 1985. The education program provided 14 workshops in five locations throughout the state and consisted of a variety of formats and levels of training. In all, 164 participants were trained at least at the introductory level with approximately 40 of these individuals taking part in the advanced levels of training. Evaluations of the training by participants and by a sample of the agency supervisors of trainees ranked the program very highly. A review of genetic history forms completed in post‐training sessions verified the expectation that training was beneficial. Trained workers completing the medical‐genetic history forms scored somewhat higher than untrained workers and much higher than parents who completed the forms without professional guidance. Medical‐genetic history forms completed by birth fathers as part of step‐parent adoptions contained little to no useful information about the birth father's genetic background.
Genetics and adoption: Forming a partnership
Authors: Delp Kathleen J. , Kaepernick Lisa A.
Published: January 2005

Genetic issues are demanding more attention in the area of public health. Adoption agencies and policymakers are beginning to address these issues where they relate to the adoption process and to the many families involved in adoption in this country. Genetic counselors need to play an active role as both educators of and consultants for adoption professionals and the families with whom they work. To facilitate a partnership between genetics and adoption we have developed a workshop intended to educate adoption professionals about the lifelong implications of genetic conditions on the adoption triad.
Transfer of genetic information in an organism
Authors: Kordyum V.A. , Shpylova S.P. , Andrienko V.I. , Sukhorada O.M. , Ruban T.A. , Deryabina O.G.
Published: January 2005

New knowledge in biology led us to a better understanding of organization and functioning of living organisms. Today, re‐evaluation of our concept of human biology is taking place. Theoretical analysis shows that taking into account the complexity of the organism and frequency of spontaneous mutations, it is impossible to explain the real time of organismal life. Therefore, besides extant systems, other repair systems must also exist. There are three “levels” at which a cell population withstands mutational pressure. First—intracellular (repair), second—intercellular (all forms of informational flows), and third—cellular replacement. Stem cells undertake regenerative functions following damage at the level of the tissue. They are also influenced by mutations, and for stem cells, it is most important that they preserve and support their full activity.
Endoscopic removal of nasal polyps in a cat using a novel surgical approach
Authors: Esterline Meredith L , Radlinsky MaryAnn G , Schermerhorn Thomas
Published: January 2005

A novel endoscopic approach for the removal of nasal polyps from a cat with upper respiratory obstruction is described. The cat's small oral cavity prevented polyp removal via traditional nasopharyngoscopy and the owner declined rhinotomy because of concerns about postoperative morbidity. Access to the nasopharynx was achieved by introducing an endoscope via gastrotomy and passing the instrument orad through the esophagus into the nasopharynx. Compared with traditional endoscopic approaches, this approach provided superior exposure of the nasopharynx and facilitated use of a larger scope and instruments than would have been possible using retroflexed nasopharyngoscopy. Multiple polyps were readily removed using this approach. The procedure was well tolerated, with minimal surgical morbidity.
Charles Hamm @80: a song well sung
Authors: Mutsaers Lutgard , Frith Simon , Cook Susan C. , Brackett David
Published: January 2005

To celebrate Charles Hamm's eightieth birthday, Popular Music is pleased to offer four tributes to a great pioneering scholar (and one of its founding editors).
Can we get rid of the ‘popular’ in popular music? A virtual symposium with contributions from the International Advisory Editors of Popular Music
Authors:   The International Advisory Editors
Published: January 2005

Recently we have been talking in the Editorial Group of the journal about the term ‘popular’, and wondering in particular about its epithetic role next to ‘music’. Some of us have questioned what the term now means, partly because it has been used less and less in media studies and cultural sociology over the last few years. Others have pointed to the fact that it remains a vital concept, even a rallying point, in certain fields such as musicology and politics.
THE SONATE AUF CONCERTENART AND CONCEPTIONS OF GENRE IN THE LATE BAROQUE
Authors: ZOHN STEVEN
Published: January 2005

Much recent writing concerning the early eighteenth-century sonata has focused on a subgenre that appropriates stylistic elements from more fully scored works. Thus several of J. S. Bach’s solo and trio sonatas signify the concerto in certain movements by adopting ritornello form and establishing instrumental roles of ‘soloist’ and ‘orchestra’, only to undermine the integrity of these roles during the course of a movement. These Sonaten auf Concertenart, and a number of similar examples by Bach’s German contemporaries, have been viewed as responses to Vivaldi’s solo concertos and especially his so-called ‘chamber concertos’, which feature similar kinds of role playing. This study, by re-examining the phenomenon of the sonata in concerto style from a number of perspectives, shows that the genre was more widespread and its origins and meanings more complex than previously recognized. Evidence for this revised view takes the form of generic titles on manuscripts and prints; music by German, Italian and French composers spanning much of the eighteenth century, from Molter to Mondonville to Mozart; some three dozen sonatas by Telemann, who exhaustively explored the genre over several decades and was perhaps its originator in Germany; and literary amalgamations of genre indicative of a broader eighteenth-century fascination with mixed types.
Octameric mitochondrial creatine kinase induces and stabilizes contact sites between the inner and outer membrane
Authors: SPEER Oliver , BÄCK Nils , BUERKLEN Tanja , BRDICZKA Dieter , KORETSKY Alan , WALLIMANN Theo , ERIKSSON Ove
Published: January 2005

We have investigated the role of the protein ubiquitous mitochondrial creatine kinase (uMtCK) in the formation and stabilization of inner and outer membrane contact sites. Using liver mitochondria isolated from transgenic mice, which, unlike control animals, express uMtCK in the liver, we found that the enzyme was associated with the mitochondrial membranes and, in addition, was located in membrane-coated matrix inclusions. In mitochondria isolated from uMtCK transgenic mice, the number of contact sites increased 3-fold compared with that observed in control mitochondria. Furthermore, uMtCK-containing mitochondria were more resistant to detergent-induced lysis than wild-type mitochondria. We conclude that octameric uMtCK induces the formation of mitochondrial contact sites, leading to membrane cross-linking and to an increased stability of the mitochondrial membrane architecture.
X-ray crystal structure of ornithine acetyltransferase from the clavulanic acid biosynthesis gene cluster
Authors: ELKINS Jonathan M. , KERSHAW Nadia J. , SCHOFIELD Christopher J.
Published: January 2005

The orf6 gene from the clavulanic acid biosynthesis gene cluster encodes an OAT (ornithine acetyltransferase). Similar to other OATs the enzyme has been shown to catalyse the reversible transfer of an acetyl group from N-acetylornithine to glutamate. OATs are Ntn (N-terminal nucleophile) enzymes, but are distinct from the better-characterized Ntn hydrolase enzymes as they catalyse acetyl transfer rather than a hydrolysis reaction. In the present study, we describe the X-ray crystal structure of the OAT, corresponding to the orf6 gene product, to 2.8 Å (1 Å=0.1 nm) resolution. The larger domain of the structure consists of an αββα sandwich as in the structures of Ntn hydrolase enzymes. However, differences in the connectivity reveal that OATs belong to a structural family different from that of other structurally characterized Ntn enzymes, with one exception: unexpectedly, the αββα sandwich of ORF6 (where ORF stands for open reading frame) displays the same fold as an DmpA (L-aminopeptidase D-ala-esterase/amidase from Ochrobactrum anthropi), and so the OATs and DmpA form a new structural subfamily of Ntn enzymes. The structure reveals an α2β2-heterotetrameric oligomerization state in which the intermolecular interface partly defines the active site. Models of the enzyme–substrate complexes suggest a probable oxyanion stabilization mechanism as well as providing insight into how the enzyme binds its two differently charged substrates.
Human recombinant membrane-bound aminopeptidase P: production of a soluble form and characterization using novel, internally quenched fluorescent substrates
Authors: MOLINARO Giuseppe , CARMONA Adriana K. , JULIANO Maria A. , JULIANO Luiz , MALITSKAYA Elena , YESSINE Marie-Andrée , CHAGNON Miguel , LEPAGE Yves , SIMMONS William H. , BOILEAU Guy , ADAM Albert
Published: January 2005

APP (aminopeptidase P) has the unique ability to cleave the N-terminal amino acid residue from peptides exhibiting a proline at P1′. Despite its putative involvement in the processing of bioactive peptides, among them the kinins, little is known about the physiological roles of both human forms of APP. The purpose of the present study is first to engineer and characterize a secreted form of hmAPP (human membrane-bound APP). Our biochemical analysis has shown that the expressed glycosylated protein is fully functional, and exhibits enzymic parameters similar to those described previously for mAPP purified from porcine or bovine lungs or expressed from a porcine clone. This soluble form of hmAPP cross-reacts with a polyclonal antiserum raised against a 469-amino-acid hmAPP fragment produced in Escherichia coli. Secondly, we synthesized three internally quenched fluorescent peptide substrates that exhibit a similar affinity for the enzyme than its natural substrates, the kinins, and a higher affinity compared with the tripeptide Arg-Pro-Pro used until now for the quantification of APP in biological samples. These new substrates represent a helpful analytical tool for rapid and reliable screening of patients susceptible to adverse reactions associated with angiotensin-converting enzyme inhibitors or novel vasopeptidase (mixed angiotensin-converting enzyme/neprilysin) inhibitors.
Random mutagenesis of bacterial luciferase: critical role of Glu175 in the control of luminescence decay
Authors: HOSSEINKHANI Saman , SZITTNER Rose , MEIGHEN Edward A.
Published: January 2005

Bacterial luciferases (LuxAB) can be readily classed as slow or fast decay luciferases based on their rates of luminescence decay in a single turnover assay. Luciferases from Vibrio harveyi and Xenorhabdus (Photorhabdus) luminescens have slow decay rates, and those from the Photobacterium genus, such as Photobacterium fisheri, P. phosphoreum and P. leiognathi, have rapid decay rates. By substitution of a 67-amino-acid stretch of P. phosphoreum LuxA in the central region of the LuxA subunit, the ‘slow’ X. luminescens luciferase was converted into a chimaeric luciferase with a significantly more rapid decay rate [Valkova, Szittner and Meighen (1999) Biochemistry 38, 13820–13828]. To understand better the role of specific residues in the classification of luciferases as slow and fast decay, we have conducted random mutagenesis on this region. One of the mutants generated by a single mutation on LuxA at position 175 [E175G (Glu175→Gly)] resulted in the ‘slow decay’ X. luminescens luciferase being converted into a luciferase with a significantly more rapid decay rate. These results indicate the importance of Glu175 in LuxA as a critical residue for differentiating between ‘slow’ and ‘fast’ luciferases and show that this distinction is primarily due to differences in aldehyde affinity and in the decomposition of the luciferase–flavin–oxygen intermediate.
The adaptor protein AP-4 as a component of the clathrin coat machinery: a morphological study
Authors: BAROIS Nicolas , BAKKE Oddmund
Published: January 2005

The four members of the AP (adaptor protein) family are heterotetrameric cytosolic complexes that are involved in the intracellular trafficking of cargo proteins between different organelles. They interact with motifs present in the cytoplasmic tails of their specific cargo proteins at different intracellular locations. While AP-1, AP-2 and AP-3 have been investigated extensively, very few studies have focused on the fourth member, AP-4. In the present study, we report on the intracellular localization of AP-4 in the MDCK (Madin–Darby canine kidney) and MelJuSo cell lines after immunogold labelling of ultrathin cryosections. We find that AP-4 is localized mainly in the Golgi complex, as well as on endosomes and transport vesicles. Interestingly, we show for the first time that AP-4 is localized with the clathrin coat machinery in the Golgi complex and in the endocytic pathway. Furthermore, we find that AP-4 is localized with the CI-MPR (cation-independent mannose 6-phosphate receptor), but not with the transferrin receptor, LAMP-2 (lysosomal-associated membrane protein-2) or invariant chain. The difference in morphology between CI-MPR/AP-4-positive vesicles and CI-MPR/AP-1-positive vesicles raises the possibility that AP-4 acts at a location different from that of AP-1 in the intracellular trafficking pathway of CI-MPR.
The septin Sept5/CDCrel-1 competes with α-SNAP for binding to the SNARE complex
Authors: BEITES Crestina L. , CAMPBELL Kristen A. , TRIMBLE William S.
Published: January 2005

SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins are supposed to mediate the docking and/or fusion of the vesicle with the plasma membrane. However, it is not clearly understood how this process is regulated. In a search for potential SNARE regulators, we recently identified septin 5 (Sept5) as a novel SNARE interacting protein. Septins were first identified as filamentous proteins required for cytokinesis in yeast. Several septins have now been identified in mammals but little is known about their functions. We have previously shown that Sept5 is predominantly expressed in the brain, where it associates with vesicles and membranes through its interaction with the SNARE domain of syntaxin 1A. Furthermore, Sept5 appears to inhibit exocytosis, possibly by regulating vesicle targeting and/or fusion events. To gain insight into the role of Sept5, we have mapped the Sept5 domains important for syntaxin binding. We also investigated the ability of Sept5 to bind to syntaxin when in various protein complexes. Although Sept5 cannot bind an nSec1–syntaxin complex, it can bind syntaxin in a SNARE complex. This interaction is occluded by the binding of α-SNAP, suggesting that Sept5 may regulate the availability of SNARE proteins through its interaction with syntaxin and the 7 S complex.
The disintegrin domain of ADAM9: a ligand for multiple β1 renal integrins
Authors: MAHIMKAR Rajeev M. , VISAYA Orvin , POLLOCK Allan S. , LOVETT David H.
Published: January 2005

Renal tubular epithelial cells in all nephron segments express a distinct member of the metalloprotease-disintegrin family, ADAM9 (adisintegrin and metalloprotease 9), in a punctate basolateral distribution co-localized to the β1 integrin chain [Mahimkar, Baricos, Visaya, Pollock and Lovett (2000) J. Am. Soc. Nephrol. 11, 595–603]. Discrete segments of the nephron express several defined β1 integrins, suggesting that ADAM9 interacts with multiple renal integrins and thereby regulates epithelial cell–matrix interactions. Intact ADAM9 and a series of deletion constructs sequentially lacking the metalloprotease domain and the disintegrin domain were assembled as chimaeras with a C-terminal GFP (green fluorescent protein) tag. Stable expression of the ADAM9/GFP protein on the surface of HEK-293 cells (human embryonic kidney 293 cells) significantly decreased adhesion to types I and IV collagen, vitronectin and laminin, but had little effect on adhesion to fibronectin. Expression of the disintegrin/cysteine-rich/GFP construct yielded a similar, but more marked pattern of decreased adhesion. Expression of the cysteine-rich/GFP construct had no effect on adhesion, indicating that the disintegrin domain was responsible for the competitive inhibition of cell–matrix binding. To define the specific renal tubular β1 integrins interacting with the ADAM9 disintegrin domain, a recombinant GST (glutathione S-transferase)-disintegrin protein was used as a substrate in adhesion assays in the presence or absence of specific integrin-blocking antibodies. Inclusion of antibodies to α1, α3, α6, αv and β1 blocked adhesion of HEK-293 cells to GST-disintegrin protein. Immobilized GST-disintegrin domain perfused with renal cortical lysates specifically recovered the α3, α6, αv and β1 integrin chains by Western analysis. It is concluded that ADAM9 is a polyvalent ligand, through its disintegrin domain, for multiple renal integrins of the β1 class.
Identification and characterization of pleckstrin-homology-domain-dependent and isoenzyme-specific Akt inhibitors
Authors: BARNETT Stanley F. , DEFEO-JONES Deborah , FU Sheng , HANCOCK Paula J. , HASKELL Kathleen M. , JONES Raymond E. , KAHANA Jason A. , KRAL Astrid M. , LEANDER Karen , LEE Ling L. , MALINOWSKI John , McAVOY Elizabeth M. , NAHAS Debbie D. , ROBINSON Ronald G. , HUBER Hans E.
Published: January 2005

We developed a high-throughput HTRF (homogeneous time-resolved fluorescence) assay for Akt kinase activity and screened approx. 270000 compounds for their ability to inhibit the three isoforms of Akt. Two Akt inhibitors were identified that exhibited isoenzyme specificity. The first compound (Akt-I-1) inhibited only Akt1 (IC50 4.6 μM) while the second compound (Akt-I-1,2) inhibited both Akt1 and Akt2 with IC50 values of 2.7 and 21 μM respectively. Neither compound inhibited Akt3 nor mutants lacking the PH (pleckstrin homology) domain at concentrations up to 250 μM. These compounds were reversible inhibitors, and exhibited a linear mixed-type inhibition against ATP and peptide substrate. In addition to inhibiting kinase activity of individual Akt isoforms, both inhibitors blocked the phosphorylation and activation of the corresponding Akt isoforms by PDK1 (phosphoinositide-dependent kinase 1). A model is proposed in which these inhibitors bind to a site formed only in the presence of the PH domain. Binding of the inhibitor is postulated to promote the formation of an inactive conformation. In support of this model, antibodies to the Akt PH domain or hinge region blocked the inhibition of Akt by Akt-I-1 and Akt-I-1,2. These inhibitors were found to be cell-active and to block phosphorylation of Akt at Thr308 and Ser473, reduce the levels of active Akt in cells, block the phosphorylation of known Akt substrates and promote TRAIL (tumour-necrosis-factor-related apoptosis-inducing ligand)-induced apoptosis in LNCap prostate cancer cells.
Processive action of cellobiohydrolase Cel7A from Trichoderma reesei is revealed as ‘burst’ kinetics on fluorescent polymeric model substrates
Authors: KIPPER Kalle , VÄLJAMÄE Priit , JOHANSSON Gunnar
Published: January 2005

Reaction conditions for the reducing-end-specific derivatization of cellulose substrates with the fluorogenic compound, anthranilic acid, have been established. Hydrolysis of fluorescence-labelled celluloses by cellobiohydrolase Cel7A from Trichoderma reesei was consistent with the active-site titration kinetics (burst kinetics), which allowed the quantification of the processivity of the enzyme. The processivity values of 88±10, 42±10 and 34±2.0 cellobiose units were found for Cel7A acting on labelled bacterial cellulose, bacterial microcrystalline cellulose and endoglucanase-pretreated bacterial cellulose respectively. The anthranilic acid derivatization also provides an alternative means for estimating the average degree of polymerization of cellulose and, furthermore, allows the quantitative monitoring of the production of reducing end groups on solid cellulose on hydrolysis by cellulases. Hydrolysis of bacterial cellulose by cellulases from T. reesei revealed that, by contrast with endoglucanase Cel5A, neither cellobiohydrolases Cel7A nor Cel6A produced detectable amounts of new reducing end groups on residual cellulose.
GCN2 phosphorylation of eIF2α activates NF-κB in response to UV irradiation
Authors: JIANG Hao-Yuan , WEK Ronald C.
Published: January 2005

In response to UV irradiation, mammalian cells elicit a gene expression programme designed to repair damage and control cell proliferation and apoptosis. Important members of this stress response include the NF-κB (nuclear factor-κB) family. However, the mechanisms by which UV irradiation activates NF-κB are not well understood. In eukaryotes, a variety of environmental stresses are recognized and remediated by a family of protein kinases that phosphorylate the α subunit of eIF2 (eukaryotic initiation factor-2). In the present study we show that NF-κB in MEF (murine embryo fibroblast) cells is activated by UV-C and UV-B irradiation through a mechanism requiring eIF2α phosphorylation. The primary eIF2α kinase in response to UV is GCN2 (general control non-derepressible-2), with PEK/PERK (pancreatic eIF2α kinase/RNA-dependent-protein-kinase-like endoplasmic-reticulum kinase) carrying out a secondary function. Our studies indicate that lowered protein synthesis accompanying eIF2α phosphorylation, combined with eIF2α kinase-independent turnover of IκBα (inhibitor of κBα), reduces the levels of IκBα in response to UV irradiation. Release of NF-κB from the inhibitory IκBα would facilitate NF-κB entry into the nucleus and targeted transcriptional control. We also find that loss of GCN2 in MEF cells significantly enhances apoptosis in response to UV exposure similar to that measured in cells deleted for the RelA/p65 subunit of NF-κB. These results demonstrate that GCN2 is central to recognition of UV stress, and that eIF2α phosphorylation provides resistance to apoptosis in response to this environmental insult.
Reaction of artemisinin with haemoglobin: implications for antimalarial activity
Authors: KANNAN Rangiah , KUMAR Krishan , SAHAL Dinkar , KUKRETI Shrikant , CHAUHAN Virander S.
Published: January 2005

Elucidation of the principal targets of the action of the antimalarial drug artemisinin is an ongoing pursuit that is important for understanding the action of this drug and for the development of more potent analogues. We have examined the chemical reaction of Hb with artemisinin. The protein-bound haem in Hb has been found to react with artemisinin much faster than is the case with free haem. It appears that the uptake of Hb and the accumulation of artemisinin into the food vacuole, together with the preferred reactivity of artemisinin with haem in Hb, may make Hb the primary target of artemisinin's antimalarial action. Both monoalkylated (HA) and dialkylated (HAA) haem derivatives of artemisinin have been isolated. These ‘haemarts’ bind to PfHRP II (Plasmodium falciparum histidine-rich protein II), inhibiting haemozoin formation, and possess a significantly decreased ability to oxidize ascorbic acid. The accelerated formation of HAA from Hb is expected to decrease the ratio of haem to its alkylated derivatives. The haemarts that are generated from ‘haemartoglobins’ may bring about the death of malaria parasite by a two-pronged effect of stalling the formation of haemozoin by the competitive inhibition of haem binding to its templates and creating a more reducing environment that is not conducive to the formation of haemozoin.
Particle dispersion in a turbulent vortex core
Authors: Marshall J. S.
Published: January 2005

A study is performed using direct numerical simulation to examine the effect of turbulence on particle dispersion in a columnar vortex. A procedure is used to generate initial conditions in which turbulence external to the vortex has the wrapped, nearly azimuthal form characteristic of turbulence around a large-scale vortex structure. This approach enables control of the initial values of the external turbulence intensity and length scale for a given vortex size and strength. The effect of turbulence on dispersion of particles by the vortex flow is examined for a wide range of different values of the initial turbulence intensity. Cases both with zero mean axial flow and unstable vortices with nonzero mean axial flow are examined. The state of the external turbulence is determined by a balance between dissipation, stretching, and vorticity reorientation and stripping from the large-scale vortex core. We examine cases with peak initial turbulence kinetic energy differing by a ratio of up to 400, and for all cases we observe that the external turbulence has a dramatic effect on the particle dispersion. The results of the study have implications for large-eddy simulation of particulate flows for which the particle concentration in the region surrounding the coherent vortex structures will not be accurately predicted if the effect of smaller-scale turbulence surrounding these structures on particle dispersion is not resolved or appropriately modeled.
High performance portable vacuum suitcase
Authors: Firpo G. , Buatier de Mongeot F. , Boragno C. , Valbusa U.
Published: January 2005

We have developed and tested a vacuum suitcase which allows to transport samples under ultrahigh vacuum (UHV) conditions. The suitcase is pumped by a new performant pumping system based on a getter pump, and it reaches an ultimate pressure lower than 3×10−11mbar, which is 2 orders of magnitude better than in the existing projects. Furthermore it has no need for a continuos power supply, no electric or magnetic field, low weight, low cost, and compactness. In order to transfer the sample from the suitcase to the main experimental chamber, in a short time (about 1h) and under UHV conditions, we have also developed a turbo pumped buffer chamber equipped with a cold trap.
Helical rays in two-dimensional resonant wave conversion
Authors: Kaufman Allan N. , Tracy Eugene R. , Brizard Alain J.
Published: January 2005

The process of resonant wave conversion (often called linear mode conversion) has traditionally been analyzed with a spatially one-dimensional slab model, for which the rays propagate in a two-dimensional phase space. However, it has recently been shown [E. R. Tracy and A. N. Kaufman, Phys. Rev. Lett. 91, 130402 (2003)] that multidimensional rays have a helical structure for conversion in two or more spatial dimensions (if their dispersion matrix is generic). In that case, a one-dimensional model is inadequate; a correct analysis requires two spatial dimensions and, thus, four-dimensional phase space. A cold-plasma model is introduced in this paper which exhibits ray helicity in conversion regions where the density and magnetic field gradients are significantly nonparallel. For illustration, such regions are identified in a model of the poloidal plane of a deuterium-tritium tokamak plasma. In each conversion region, characterized by a six-sector topology, rays in the sector for incident and reflected magnetosonic waves exhibit significant helicity. A detailed analytic and numerical study of helical rays in this sector is developed for a “symmetric-wedge” model.