436 research outputs found

    Vogelstimmen-Forschung : eine scientia amabilis ; meinem Freund Hans-Heiner Bergmann zum 70. Geburtstag

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    Interesse fĂŒr und Liebe zu den Vögeln und vor allem zu den Vogelstimmen entwickelten sich an getrennten Orten: Bei Hans-Heiner Bergmann in Marburg und OsnabrĂŒck, bei Hans-Wolfgang Helb in Erlangen und Kaiserslautern. Neue Forschungsmöglichkeiten und moderne Technik wie die Sonagraphie ließen aus den beiden Ornitho-Akustikern ein Kollegen-Team werden. Beide Stimmen-Sammlungen zusammen mĂŒndeten in gemeinsamen Publikationen, auch in dem Werk „Die Stimmen der Vögel Europas“.Interest and passion for birds and bird songs in particular developed at different localities: for Hans-Heiner Bergmann in Marburg and OsnabrĂŒck and for Hans-Wolfgang Helb in Erlangen and Kaiserslautern. New research opportunities and modern technology like sonography formed a team of ornithologically interested bioacustics colleagues. Both their collections of bird songs and vocalisations led to combined publications including the book “Die Stimmen der Vögel Europas”

    Differences depending on the gender in the clattering of the White Stork Ciconia ciconia

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    Im Rahmen einer Freilandstudie in Rheinland-Pfalz (1999- 2001) wurden geschlechtsbedingte Eigenschaften des Klapperns beim Weißstorch untersucht. Zahlreiche Unterschiede zwischen den Geschlechtern (9 MĂ€nnchen und 9 Weibchen) wurden gefunden. Eine einfache zweidimensionale Matrix der Parameter F2M [Hz] und DIK [ms], basierend auf den Mittelwerten der einzelnen Individuen, machte eine Trennung der Geschlechter möglich. Wir vermuten, dass die gefundenen Differenzen auf Unterschieden der Kopf- und Schnabelanatomie bei den Geschlechtern beruhen.The variation of the “clattering” was studied in groups of 9 female and 9 male individually marked White Storks in the southern part of Rhineland-Palatinate. We gathered and compared data to find a gender-based characterization in this instrumental noise. A separation of genders was possible by a simple 2-d matrix of the parameters F2M [Hz] and DIK [ms], based on mean of each individual. We assume that the discovered differences depend on the anatomic dimorphism of the beak and of the anatomy of the head

    New and Improved Diagnostics for Detection of Drug-Resistant Pulmonary Tuberculosis.

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    PURPOSE OF REVIEW: Tuberculosis (TB) remains a global emergency and continues to kill 1.7 million people globally each year. Drug-resistant TB is now well established throughout the world and most TB patients are not being screened for drug resistance due to lack of laboratory resources and rapid accurate point-of-care tests. Accurate and rapid diagnosis of TB and drug-resistant TB is of paramount importance in establishing appropriate clinical management and infection control measures. During the past decade, there have been significant advances in diagnostic technologies for TB and drug-resistant TB. The purpose of this article is to review the current data, recommendations and evidence base for these tests. RECENT FINDINGS: Second-line drug susceptibility testing (DST) is complex and expensive. Automated liquid culture systems and molecular line probe assays are recommended by the WHO as the current 'gold standard' for first-line DST. Liquid culture DST for aminoglycosides, polypeptides and fluoroquinolones has been shown to have relatively good reliability and reproducibility for diagnosis of extensively drug-resistant TB; however, DST for other second-line drugs (ethionamide, prothionamide, cycloserine, terizidone, para-aminosalicylic acid, clofazimine, amoxicillin-clavulanate, clarithromycin, linezolid) is not recommended. Automated liquid culture systems are currently recommended by the WHO as the 'gold standard' for second-line DST. SUMMARY: In this review, we describe the phenotypic and genotypic methods currently available for the diagnosis of TB and drug-resistant forms of Mycobacterium tuberculosis and discuss future prospects for TB diagnostics. Current technologies for the detection of drug resistant M. tuberculosis vary greatly in terms of turnaround time, cost and complexity. Ultimately, the 'holy grail' diagnostic for TB must fulfil all technical specifications for a good point-of-care test, screen for drug resistance concurrently and be adaptable to the various health system levels and to countries with diverse economic status and TB burden. © 2011 Lippincott Williams & Wilkins, Inc

    Transcriptional Regulation of Multi-Drug Tolerance and Antibiotic-Induced Responses by the Histone-Like Protein Lsr2 in M. tuberculosis

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    Multi-drug tolerance is a key phenotypic property that complicates the sterilization of mammals infected with Mycobacterium tuberculosis. Previous studies have established that iniBAC, an operon that confers multi-drug tolerance to M. bovis BCG through an associated pump-like activity, is induced by the antibiotics isoniazid (INH) and ethambutol (EMB). An improved understanding of the functional role of antibiotic-induced genes and the regulation of drug tolerance may be gained by studying the factors that regulate antibiotic-mediated gene expression. An M. smegmatis strain containing a lacZ gene fused to the promoter of M. tuberculosis iniBAC (PiniBAC) was subjected to transposon mutagenesis. Mutants with constitutive expression and increased EMB-mediated induction of PiniBAC::lacZ mapped to the lsr2 gene (MSMEG6065), a small basic protein of unknown function that is highly conserved among mycobacteria. These mutants had a marked change in colony morphology and generated a new polar lipid. Complementation with multi-copy M. tuberculosis lsr2 (Rv3597c) returned PiniBAC expression to baseline, reversed the observed morphological and lipid changes, and repressed PiniBAC induction by EMB to below that of the control M. smegmatis strain. Microarray analysis of an lsr2 knockout confirmed upregulation of M. smegmatis iniA and demonstrated upregulation of genes involved in cell wall and metabolic functions. Fully 121 of 584 genes induced by EMB treatment in wild-type M. smegmatis were upregulated (“hyperinduced”) to even higher levels by EMB in the M. smegmatis lsr2 knockout. The most highly upregulated genes and gene clusters had adenine-thymine (AT)–rich 5-prime untranslated regions. In M. tuberculosis, overexpression of lsr2 repressed INH-mediated induction of all three iniBAC genes, as well as another annotated pump, efpA. The low molecular weight and basic properties of Lsr2 (pI 10.69) suggested that it was a histone-like protein, although it did not exhibit sequence homology with other proteins in this class. Consistent with other histone-like proteins, Lsr2 bound DNA with a preference for circular DNA, forming large oligomers, inhibited DNase I activity, and introduced a modest degree of supercoiling into relaxed plasmids. Lsr2 also inhibited in vitro transcription and topoisomerase I activity. Lsr2 represents a novel class of histone-like proteins that inhibit a wide variety of DNA-interacting enzymes. Lsr2 appears to regulate several important pathways in mycobacteria by preferentially binding to AT-rich sequences, including genes induced by antibiotics and those associated with inducible multi-drug tolerance. An improved understanding of the role of lsr2 may provide important insights into the mechanisms of action of antibiotics and the way that mycobacteria adapt to stresses such as antibiotic treatment

    Tuberculosis diagnostics and biomarkers: needs, challenges, recent advances, and opportunities

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    Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics

    Rapid and Accurate Detection of Mycobacterium tuberculosis in Sputum Samples by Cepheid Xpert MTB/RIF Assay-A Clinical Validation Study

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    Background: A crucial impediment to global tuberculosis control is the lack of an accurate, rapid diagnostic test for detection of patients with active TB. A new, rapid diagnostic method, (Cepheid) Xpert MTB/RIF Assay, is an automated sample preparation and real-time PCR instrument, which was shown to have good potential as an alternative to current reference standard sputum microscopy and culture.Methods: We performed a clinical validation study on diagnostic accuracy of the Xpert MTB/RIF Assay in a TB and HIV endemic setting. Sputum samples from 292 consecutively enrolled adults from Mbeya, Tanzania, with suspected TB were subject to analysis by the Xpert MTB/RIF Assay. The diagnostic performance of Xpert MTB/RIF Assay was compared to standard sputum smear microscopy and culture. Confirmed Mycobacterium tuberculosis in a positive culture was used as a reference standard for TB diagnosis.Results: Xpert MTB/RIF Assay achieved 88.4% (95% CI = 78.4% to 94.9%) sensitivity among patients with a positive culture and 99% (95% CI = 94.7% to 100.0%) specificity in patients who had no TB. HIV status did not affect test performance in 172 HIV-infected patients (58.9% of all participants). Seven additional cases (9.1% of 77) were detected by Xpert MTB/RIF Assay among the group of patients with clinical TB who were culture negative. Within 45 sputum samples which grew non-tuberculous mycobacteria the assay's specificity was 97.8% (95% CI = 88.2% to 99.9%).Conclusions: The Xpert MTB/RIF Assay is a highly sensitive, specific and rapid method for diagnosing TB which has potential to complement the current reference standard of TB diagnostics and increase its overall sensitivity. Its usefulness in detecting sputum smear and culture negative patients needs further study. Further evaluation in high burden TB and HIV areas under programmatic health care settings to ascertain applicability, cost-effectiveness, robustness and local acceptance are required
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