Search

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The first generation of biochemical studies of complex, iron-sulfur-cluster-containing [FeFe]-hydrogenases and Mo-nitrogenase were carried out on enzymes purified from Clostridium pasteurianum (strain W5). Previous studies suggested that two distinct [FeFe]-hydrogenases are expressed differentially under nitrogen-fixing and non-nitrogen-fixing conditions. As a result, the first characterized [FeFe]-hydrogenase (CpI) is presumed to have a primary role in central metabolism, recycling reduced electron carriers that accumulate during fermentation via proton reduction. A role for capturing reducing equivalents released as hydrogen during nitrogen fixation has been proposed for the second hydrogenase, CpII. Biochemical characterization of CpI and CpII indicated CpI has extremely high hydrogen production activity in comparison to CpII, while CpII has elevated hydrogen oxidation activity in comparison to CpI when assayed under the same conditions. This suggests that these enzymes have evolved a catalytic bias to support their respective physiological functions. Using the published genome of C. pasteurianum (strain W5) hydrogenase sequences were identified, including the already known [NiFe]-hydrogenase, CpI, and CpII sequences, and a third hydrogenase, CpIII was identified in the genome as well. Quantitative real-time PCR experiments were performed in order to analyze transcript abundance of the hydrogenases under diazotrophic and non-diazotrophic growth conditions. There is a markedly reduced level of CpI gene expression together with concomitant increases in CpII gene expression under nitrogen-fixing conditions. Structure-based analyses of the CpI and CpII sequences reveal variations in their catalytic sites that may contribute to their alternative physiological roles. This work demonstrates that the physiological roles of CpI and CpII are to evolve and to consume hydrogen, respectively, in concurrence with their catalytic activities in vitro, with CpII capturing excess reducing equivalents under nitrogen fixation conditions. Comparison of the primary sequences of CpI and CpII and their homologs provides an initial basis for identifying key structural determinants that modulate hydrogen production and hydrogen oxidation activities.

The first generation of biochemical studies of complex, iron-sulfur-cluster-containing [FeFe]-hydrogenases and Mo-nitrogenase were carried out on enzymes purified from Clostridium pasteurianum (strain W5). Previous studies suggested that two distinct [FeFe]-hydrogenases are expressed differentially under nitrogen-fixing and non-nitrogenfixing conditions. As a result, the first characterized [FeFe]-hydrogenase (CpI) is presumed to have a primary role in central metabolism, recycling reduced electron carriers that accumulate during fermentation via proton reduction. A role for capturing reducing equivalents released as hydrogen during nitrogen fixation has been proposed for the second hydrogenase, CpII. Biochemical characterization of CpI and CpII indicated CpI has extremely high hydrogen production activity in comparison to CpII, while CpII has elevated hydrogen oxidation activity in comparison to CpI when assayed under the same conditions. This suggests that these enzymes have evolved a catalytic bias to support their respective physiological functions. Using the published genome of C. pasteurianum (strain W5) hydrogenase sequences were identified, including the already known [NiFe]-hydrogenase, CpI, and CpII sequences, and a third hydrogenase, CpIII was identified in the genome as well. Quantitative real-time PCR experiments were performed in order to analyze transcript abundance of the hydrogenases under diazotrophic and non-diazotrophic growth conditions. There is a markedly reduced level of CpI gene expression together with concomitant increases in CpII gene expression under nitrogen-fixing conditions. Structure-based analyses of the CpI and CpII sequences reveal variations in their catalytic sites that may contribute to their alternative physiological roles. This work demonstrates that the physiological roles of CpI and CpII are to evolve and to consume hydrogen, respectively, in concurrence with their catalytic activities in vitro, with CpII capturing excess reducing equivalents under nitrogen fixation conditions. Comparison of the primary sequences of CpI and CpII and their homologs provides an initial basis for identifying key structural determinants that modulate hydrogen production and hydrogen oxidation activities. [ABSTRACT FROM AUTHOR]

The article presents a study that analyzes a collagen II degradation (C2C) protein and a collagen II formation (CPII) protein in Asian elephants (Elephas maximus). It states that two available immunoassays were used to measure C2C and CPII proteins in Asian elephants. It says that further studies are needed to evaluate their function to diagnose osteoarthritis in proboscidae.

The light-harvesting complex (LHC) of higher plants isolated using Triton X-100 has been studied during its transformation into a monomeric form known as CPII. The change was accomplished by gradually increasing the concentration of the detergent, sodium dodecyl sulfate (SDS). Changes in the red spectral region of the absorption, circular dichroism (CD), and linear dichroism spectra occurring during this treatment have been observed at room temperature. According to a current hypothesis the main features of the visible region absorption and CD spectra of CPII can be explained reasonably successfully in terms of an exciton coupling among its chlorophyll (Chl) b molecules. We suggest that the spectral differences between the isolated LHC and the CPII may be understood basically in terms of an exciton coupling between the Chl b core of a given CPII unit and at least one of the Chl a's of either the same or the adjacent CPII. We propose that this Chl a-Chl b coupling existing in LHC disappears upon segregation into CPII, probably as a result of a detergent-related overall rotation of the strongly coupled Chl b core which changes the relative orientations of the two types of pigments and thus the nature of their coupling. [ABSTRACT FROM AUTHOR]

The circular dichroism (CD) method was applied to study the molecular organization of P700, antenna chlorophyll and protein of photosystem 1 complexes (CP1), isolated from chloroplasts under mild treatment with Triton X-100. Analysis of CD spectra and protein: chlorophyll: P700 ratios for CP1 complexes that were different in their chlorophyll content indicate that CP1 preparations can be considered as a mixture of CP1-RC, containing P700 (10-20%), and CP1-LH without P700 (80-90%). Both types of complexes contain approximately 25 chlorophyll molecules, and the destruction of their spatial organization with detergents represents a cooperative transition. The rate of chlorophyll destruction in CP1-LH is much higher than that in CP1-RC. In both complexes a 65 kDa polypeptide predominates, whose secondary structure (typical for α/β proteins) is stable to Triton X-100 and does not depends on the chlorophyll content. Chlorophyll seems to be grouped in clusters (5-7 molecules) in the hydrophobic cores of 2-3 parallel α/β domains of the 65 kDa protein. Only one of the clusters in CP1-RC includes P700; on P700 photooxidation the change of its interaction with the nearest pigment environment results in a complicated shape of the light-induced CD spectra. [ABSTRACT FROM AUTHOR]

Background: Hand osteoarthritis (OA) is one of the most common joint diseases, but studies on biomarkers are rare. The aim of this explorative study was (a) to evaluate potential biomarkers of hand OA, (b) to identify an optimal time point to sample venous blood, and (c) to correlate biomarker levels with radiological and clinical scores. Methods: Four female cohorts were investigated. One with a more Heberden-accentuated OA and one with a more Bouchard-accentuated hand OA, and two symptom-free control groups aged 20–30 or 50–75 years. The venous blood was sampled before and at eight time points after mechanical exercise of the OA hand. X-rays of OA hands were assessed using the Kellgren and Lawrence as well as Kallman scores. Participants were evaluated clinically using the AUSCAN™ Index, visual analog scale (VAS), and Health Assessment Questionnaire (HAQ). Serum levels of seven biomarkers were measured by ELISA. Results. The concentrations of CPII, COMP, IL-15, sVCAM-1, NGAL, and PIIANP were significantly increased within 15 min after exercise. PIIANP was markedly elevated in the Heberden-accentuated OA group as compared to both control groups, but did not correlate with any radiological or clinical score. Analysis of the probabilistic index further revealed that CPII can distinguish between Bouchard's OA and premenopausal controls whereas COMP can discriminate between Bouchard's and Heberden's OA. Conclusions: This study demonstrates that even previously undetectable biomarkers can be quantified in serum after mechanical exercise. Future larger studies are needed to determine specificity and sensitivity of these markers and their ability to diagnose even pre-radiological OA. [ABSTRACT FROM AUTHOR]

Background: To determine the association between time from injury to ACL reconstruction (Time Injury-ACLR ) and biochemical markers of cartilage metabolism and inflammation six months following ACL reconstruction (ACLR)., Methods: Individuals with a unilateral ACL injury were enrolled at initial presentation in the orthopedic clinic; blood was collected six months following ACLR. Enzyme-linked immunosorbent assays were used to analyze the ratio of serum concentrations of type-II collagen breakdown (C2C) to synthesis (CPII), plasma matrix metalloproteinase-3 (MMP-3), interleukin-6 (IL-6), and serum aggrecan neoepitope (ARGS). We used separate linear regressions to assess associations between biochemical markers and Time Injury-ACLR ., Results: Twenty-two participants (50% females, mean [SD], age 21.9 [4.5] years old; BMI 23.8 [2.6] kg/m 2 ) completed the study. Time Injury-ACLR ranged from nine to 67days (31.0 [14.4days]). Greater Time Injury-ACLR predicted greater serum C2C:CPII ratios six months following ACLR (C2C:CPII=0.15 [0.02], R 2 =0.213, P=0.030). Males (R 2 =0.733, P=0.001) but not females (R 2 =0.030, P=0.609) demonstrated a significant association between greater C2C:CPII and Time Injury-ACLR at the six-month follow-up exam. Time Injury-ACLR did not associate with IL-6, MMP-3, or ARGS at six months., Conclusions: Greater time between injury and ACL reconstruction was associated with greater serum C2C:CPII six months following ACLR in males but not females, and IL-6, MMP-3, and ARGS levels were not associated with Time Injury-ACLR in males or females. The time between ACL injury and ACLR may affect collagen metabolism in males and should be further investigated in a larger study along with other patient-relevant outcomes., (Copyright © 2018 Elsevier B.V. All rights reserved.)