Comparison of forest attributes derived from two terrestrial lidar systems.

Abstract Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences between scanners in estimates of effective plant area index were greater than differences between sites. Both scanners provided a detailed digital model of forest structure, and gross structural characterizations (including crown dimensions and position) were relatively robust; but comparison of canopy density metrics may require consideration of scanner attributes

Reinigung des Transkriptionsfaktors IIIC1 der RNA-Polymerase III und Identifizierung potentieller TFIIIC1 Untereinheiten

Die humane RNA-Polymerase III synthetisiert kleine, nicht proteinkodierende RNAs, die unterschiedlichen Gengruppen angehören und für deren Herstellung verschiedene Transkriptionsfaktoren benötigt werden. Ein zentraler Transkriptionsfaktor im Polymerase-III-System ist TFIIIC1, der für die Expression aller Polymerase-III-abhängigen Gene essentiell benötigt wird. Seine Struktur und Wirkungsweise konnte jedoch bisher nicht aufgeklärt werden. In dieser Arbeit wurde zunächst die Beziehung von TFIIIC1 zu anderen, die Polymerase III-Transkription stimulierenden Proteinen untersucht. Es konnte gezeigt werden, dass TFIIIC1 in keinerlei Zusammenhang mit der Proteinkinase CK2 oder der DNA-Topoisomerase I steht, die beide in anderen experimentellen Systemen einen positiven Einfluss auf die Effizienz der Polymerase III-Transkription aufgewiesen hatten. Voraussetzung für ein besseres Verständnis der Wirkungsweise von TFIIIC1 ist seine weitere Reinigung bis hin zur Sequenzierung und Klonierung seiner Untereinheiten. Hierfür wurde zunächst nach dem Standard-Protokoll eine Phosphocellulose-Chromatographie durchgeführt, der eine MonoQ-Chromatographie folgte. Als neuer Kationenaustauscher wurde anschließend das MonoS-Säulenmaterial eingesetzt, das zum einen eine sehr gute Reinigungseffizienz zeigte und über das zum anderen zwei verschiedene Formen von TFIIIC1 voneinander getrennt werden konnten. Das unterschiedliche chromatographische Verhalten dieser Formen ist vermutlich auf einen unterschiedlichen Modifikationsgrad zurückzuführen. Da auch bei der MonoS-Chromatographie mit TFIIIC1-like zwei Aktivitätspeaks gefunden wurden, ist es möglich, dass es sich bei TFIIIC1-like um eine Subpopulation von TFIIIC1 handelt. Diese besteht wiederum selbst aus zwei unterschiedlichen Formen, so dass man von mindestens vier verschiedenen Formen von TFIIIC1 sprechen kann. Ein ergänzender Weg zur Darstellung der Untereinheiten von TFIIIC1 bestand in der Assemblierung und Isolierung von vollständigen und partiellen VA I-Transkriptionskomplexen. Hierfür wurden neben Kontroll-Gelfiltrationsläufen TFIIIC2-TFIIIBb-VAI- sowie TFIIIC2-TFIIIBb-TFIIIC1-VAI-Teilkomplexe assembliert, die anschließend über eine S500-Gelfiltration von den freien, nicht in den Komplex integrierten Proteinen abgetrennt wurden. Die isolierten Teilkomplexe konnten durch Zugabe fehlender Faktoren und der Polymerase III vervollständigt werden und zeigten in Anwesenheit von Nukleotiden eine sehr gute Transkriptionsaktivität. Nach Abgleich mit den entsprechenden Kontroll-Gelfiltrationsläufen konnten schließlich sechs potentiell zu TFIIIC1 gehörende Untereinheiten in einem silbergefärbten SDS-Gel identifiziert werden; die gefundenen Polypeptide besaßen eine Größe von etwa 43, 57, 65, 69, 140 und 164 kDa. Diese Größen konnten auch durch klassische Chromatographie-Experimente bestätigt werden

Surfactant protein B gene variations enhance susceptibility to squamous cell carcinoma of the lung in German patients

Genetic factors are thought to influence the risk for lung cancer. Since pulmonary surfactant mediates the response to inhaled carcinogenic substances, candidate genes may be among those coding for pulmonary surfactant proteins. In the present matched case–control study a polymorphism within intron 4 of the gene coding for surfactant specific protein B was analysed in 357 individuals. They were divided into 117 patients with lung cancer (40 patients with small cell lung cancer, 77 patients with non small cell lung cancer), matched controls and 123 healthy individuals. Surfactant protein B gene variants were analysed using specific PCR and cloned surfactant protein B sequences as controls. The frequency of the intron 4 variation was similar in both control groups (13.0% and 9.4%), whereas it was increased in the small cell lung cancer group (17.5%) and the non small cell lung cancer group (16.9%). The gene variation was found significantly more frequently in patients with squamous cell carcinoma (25.0%, P=0.016, odds ratio=3.2, 95%CI=1.24–8.28) than in the controls. These results indicate an association of the surfactant protein B intron 4 variants and/or its flanking loci with mechanisms that may enhance lung cancer susceptibility, especially to squamous cell carcinoma of the lung

Universal Stress Proteins Are Important for Oxidative and Acid Stress Resistance and Growth of Listeria monocytogenes EGD-e In Vitro and In Vivo

Background: Pathogenic bacteria maintain a multifaceted apparatus to resist damage caused by external stimuli. As part of this, the universal stress protein A (UspA) and its homologues, initially discovered in Escherichia coli K-12 were shown to possess an important role in stress resistance and growth in several bacterial species. Methods and Findings: We conducted a study to assess the role of three homologous proteins containing the UspA domain in the facultative intracellular human pathogen Listeria monocytogenes under different stress conditions. The growth properties of three UspA deletion mutants (deltalmo0515, deltalmo1580 and deltalmo2673) were examined either following challenge with a sublethal concentration of hydrogen peroxide or under acidic conditions. We also examined their ability for intracellular survival within murine macrophages. Virulence and growth of usp mutants were further characterized in invertebrate and vertebrate infection models. Tolerance to acidic stress was clearly reduced in Δlmo1580 and deltalmo0515, while oxidative stress dramatically diminished growth in all mutants. Survival within macrophages was significantly decreased in deltalmo1580 and deltalmo2673 as compared to the wild-type strain. Viability of infected Galleria mellonella larvae was markedly higher when injected with deltalmo1580 or deltalmo2673 as compared to wild-type strain inoculation, indicating impaired virulence of bacteria lacking these usp genes. Finally, we observed severely restricted growth of all chromosomal deletion mutants in mice livers and spleens as compared to the load of wild-type bacteria following infection. Conclusion: This work provides distinct evidence that universal stress proteins are strongly involved in listerial stress response and survival under both in vitro and in vivo growth conditions

Analyses of association between PPAR gamma and EPHX1 polymorphisms and susceptibility to COPD in a Hungarian cohort, a case-control study

<p>Abstract</p> <p>Background</p> <p>In addition to smoking, genetic predisposition is believed to play a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Genetic association studies of new candidate genes in COPD may lead to improved understanding of the pathogenesis of the disease.</p> <p>Methods</p> <p>Two proposed casual single nucleotide polymorphisms (SNP) <it>(rs1051740, rs2234922) </it>in microsomal epoxide hydrolase (<it>EPHX1</it>) and three SNPs <it>(rs1801282, rs1800571, rs3856806) </it>in peroxisome proliferator-activated receptor gamma (<it>PPARG</it>), a new candidate gene, were genotyped in a case-control study (272 COPD patients and 301 controls subjects) in Hungary. Allele frequencies and genotype distributions were compared between the two cohorts and trend test was also used to evaluate association between SNPs and COPD. To estimate the strength of association, odds ratios (OR) (with 95% CI) were calculated and potential confounding variables were tested in logistic regression analysis. Association between haplotypes and COPD outcome was also assessed.</p> <p>Results</p> <p>The distribution of imputed <it>EPHX1 </it>phenotypes was significantly different between the COPD and the control group (P = 0.041), OR for the slow activity phenotype was 1.639 (95% CI = 1.08- 2.49; P = 0.021) in our study. In logistic regression analysis adjusted for both variants, also age and pack-year, the rare allele of His447His of <it>PPARG </it>showed significant association with COPD outcome (OR = 1.853, 95% CI = 1.09-3.14, P = 0.0218). In haplotype analysis the GC haplotype of <it>PPARG </it>(OR = 0.512, 95% CI = 0.27-0.96, P = 0.035) conferred reduced risk for COPD.</p> <p>Conclusions</p> <p>The "slow" activity-associated genotypes of <it>EPHX1 </it>were associated with increased risk of COPD. The minor His447His allele of <it>PPARG </it>significantly increased; and the haplotype containing the minor Pro12Ala and the major His447His polymorphisms of <it>PPARG </it>decreased the risk of COPD.</p

Molecular genetics and its possible implications to livestock improvement

يمكن تقسيم الدراسات حول الفلاحين و المجتمع الريفي و الفلاحة الجزائرية إلى الأقسام الأربعة التالية : خلال مرحلة أولى تبدأ من الاستقلال إلى نهاية الستينات، لاحظنا فيضا من الإصدارات و الأعمال التي تناولت –منجهة- آثار الأستيطان الاستعماري على القطاع الفلاحي و الريفي و من جهة أخرى –التسيير الذاتي. لقد تأثرت هذه الدراسات و بشكل خاص النظرية منها، بالاتجاهات الماركسية التي انشغلت بموضوعات البناء الاشتراكي و الأشكال اللامركزية للملكية. إن جل هذه الدراسات كان من تأليف باحثين أجانب، إذ يجب انتظار النصف ..