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951.
952.
David L. Prole Patrick F. Chinnery Nick S. Jones 《The Journal of biological chemistry》2020,295(51):17588
Mitochondrial DNA (mtDNA) encodes proteins and RNAs that support the functions of mitochondria and thereby numerous physiological processes. Mutations of mtDNA can cause mitochondrial diseases and are implicated in aging. The mtDNA within cells is organized into nucleoids within the mitochondrial matrix, but how mtDNA nucleoids are formed and regulated within cells remains incompletely resolved. Visualization of mtDNA within cells is a powerful means by which mechanistic insight can be gained. Manipulation of the amount and sequence of mtDNA within cells is important experimentally and for developing therapeutic interventions to treat mitochondrial disease. This review details recent developments and opportunities for improvements in the experimental tools and techniques that can be used to visualize, quantify, and manipulate the properties of mtDNA within cells. 相似文献
953.
Protein translocation occurs across the energy-conserving bacterial membrane at the SecYEG channel. The crystal structure of the channel has revealed a possible mechanism for gating and opening. This study evaluates the plug hypothesis using cysteine crosslink experiments in combination with various allelic forms of the Sec complex. The results demonstrate that the SecY plug domain moves away from the center of the channel toward SecE during polypeptide translocation, and further show that the translocation-enhancing prlA3 mutation and SecG subunit change the properties of channel gating. Locking the plug in the open state preactivates the Sec complex, and a super-active translocase can be created when combined with the prlA4 mutation located in the pore of the channel. Dimerization of the Sec complex, which is essential for translocase activity, relocates the plug toward the open position. We propose that oligomerization may result in SecYEG cooperative interactions important to prime the translocon function. 相似文献
954.
Chalberg TW Portlock JL Olivares EC Thyagarajan B Kirby PJ Hillman RT Hoelters J Calos MP 《Journal of molecular biology》2006,357(1):28-48
The site-specific integrase from bacteriophage phiC31 functions in mammalian cells and is being applied for genetic engineering, including gene therapy. The phiC31 integrase catalyzes precise, unidirectional recombination between its 30-40-bp attP and attB recognition sites. In mammalian cells, the enzyme also mediates integration of plasmids bearing attB into native sequences that have partial sequence identity with attP, termed pseudo attP sites. Here, we analyzed the features of phiC31-mediated integration into pseudo attP sites in the human genome. Sequence analysis of 196 independent integration events derived from three cell lines revealed approximately 101 integration sites: 56% of the events were recurrent integrations distributed among 19 pseudo attP sequences. Bioinformatics analysis revealed a approximately 30-bp palindromic consensus sequence motif shared by all of the repeat occurrences and most of the single occurrence sites, verifying that phiC31-mediated integration into pseudo attP sites is significantly guided by DNA sequence recognition. The most favored unique sequence in these cell lines occurred at chromosome 19q13.31 and accounted for 7.5% of integration events. Other frequent integration sites were in three specific sequences in subfamilies of ERVL and L1 repetitive sequences, accounting for an additional 17.9% of integration events. Integrations could occur in either orientation at a pseudo attP site, were often accompanied by small deletions, and typically occurred in a single copy per cell. A number of aberrant events were also described, including large deletions and chromosome rearrangements. phiC31 integrase-mediated integration only slightly favored genes and did not favor promoter regions. Gene density and expression studies suggested chromatin context effects. An analysis of the safety of integration sites in terms of proximity to cancer genes suggested minimal cancer risk. We conclude that integration systems derived from phiC31 integrase have great potential utility. 相似文献
955.
Giraud MF Paumard P Sanchez C Brèthes D Velours J Dautant A 《Journal of structural biology》2012,177(2):490-497
The F1FO-ATP synthase is a rotary molecular nanomotor. F1 is a chemical motor driven by ATP hydrolysis while FO is an electrical motor driven by the proton flow. The two stepping motors are mechanically coupled through a common rotary shaft. Up to now, the three available crystal structures of the F1c10 sub-complex of the yeast F1FO-ATP synthase were isomorphous and then named yF1c10(I). In this crystal form, significant interactions of the c10-ring with the F1-head of neighboring molecules affected the overall conformation of the F1-c-ring complex. The symmetry axis of the F1-head and the inertia axis of the c-ring were tilted near the interface between the F1-central stalk and the c-ring rotor, resulting in an unbalanced machine. We have solved a new crystal form of the F1c10 complex, named yF1c10(II), inhibited by adenylyl-imidodiphosphate (AMP-PNP) and dicyclohexylcarbodiimide (DCCD), at 6.5 Å resolution in which the crystal packing has a weaker influence over the conformation of the F1-c-ring complex. yF1c10(II) provides a model of a more efficient generator. yF1c10(II) and bovine bF1c8 structures share a common rotor architecture with the inertia center of the F1-stator close to the rotor axis. 相似文献
956.
Domnic Mijele Vincent Obanda Patrick Omondi Ramón C. Soriguer Francis Gakuya Moses Otiende Peter Hongo Samer Alasaad 《PloS one》2013,8(7)
Background
Very few studies have ever focused on the elephants that are wounded or killed as local communities attempt to scare these animals away from their settlements and farms, or on the cases in which local people take revenge after elephants have killed or injured humans. On the other hand, local communities live in close proximity to elephants and hence can play a positive role in elephant conservation by informing the authorities of the presence of injured elephants.Methodology/Principal Findings
Between 2007 and 2011, 129 elephants were monitored in Masai Mara (Kenya), of which 54 had various types of active (intentionally caused) or passive (non-intentionally caused) injuries. Also studied were 75 random control samples of apparently unaffected animals. The observed active injuries were as expected biased by age, with adults suffering more harm; on the other hand, no such bias was observed in the case of passive injuries. Bias was also observed in elephant sex since more males than females were passively and actively injured. Cases of passive and active injuries in elephants were negatively related to the proximity to roads and farms; the distribution of injured elephants was not affected by the presence of either human settlements or water sources. Overall more elephants were actively injured during the dry season than the wet season as expected. Local communities play a positive role by informing KWS authorities of the presence of injured elephants and reported 43% of all cases of injured elephants.Conclusions
Our results suggest that the negative effect of local communities on elephants could be predicted by elephant proximity to farms and roads. In addition, local communities may be able to play a more positive role in elephant conservation given that they are key informants in the early detection of injured elephants. 相似文献957.
Boyle PM Burrill DR Inniss MC Agapakis CM Deardon A Dewerd JG Gedeon MA Quinn JY Paull ML Raman AM Theilmann MR Wang L Winn JC Medvedik O Schellenberg K Haynes KA Viel A Brenner TJ Church GM Shah JV Silver PA 《Journal of biological engineering》2012,6(1):8
ABSTRACT: BACKGROUND: Plant biotechnology can be leveraged to produce food, fuel, medicine, and materials. Standardized methods advocated by the synthetic biology community can accelerate the plant design cycle, ultimately making plant engineering more widely accessible to bioengineers who can contribute diverse creative input to the design process. RESULTS: This paper presents work done largely by undergraduate students participating in the 2010 International Genetically Engineered Machines (iGEM) competition. Described here is a framework for engineering the model plant Arabidopsis thaliana with standardized, BioBrick compatible vectors and parts available through the Registry of Standard Biological Parts (www.partsregistry.org). This system was used to engineer a proof-of-concept plant that exogenously expresses the taste-inverting protein miraculin. CONCLUSIONS: Our work is intended to encourage future iGEM teams and other synthetic biologists to use plants as a genetic chassis. Our workflow simplifies the use of standardized parts in plant systems, allowing the construction and expression of heterologous genes in plants within the timeframe allotted for typical iGEM projects. 相似文献
958.
Cytochrome c
6
, (cyt c
6) a soluble monoheme electron transport protein, was isolated and characterized from the chlorophyll d-containing cyanobacterium Acaryochoris marina, the type strain MBIC11017. The protein was purified using ammonium sulfate precipitation, ion exchange and gel filtration
column chromatography, and fast performance liquid chromatography. Its molecular mass and pI have been determined to be 8.87 kDa
and less than 4.2, respectively, by mass spectrometry and isoelectrofocusing (IEF). The protein has an alpha helical structure
as indicated by CD (circular dichroism) spectroscopy and a reduction midpoint potential (E
m) of +327 mV versus the normal hydrogen electrode (NHE) as determined by redox potentiometry. Its potential role in electron
transfer processes is discussed. 相似文献
959.
Warren D. Brady Matthew J. Eick Paul R. Grossl Patrick V. Brady 《Soil & Sediment Contamination》2003,12(4):541-564
Consideration of monitored natural attenuation (MNA) as a remedy component for metals-contaminated sites can be achieved using a site-specific screening approach, followed by application of one or a series of sequential extraction measurements. Hazardous waste sites contaminated with metals can be screened for the implementation of monitored natural attenuation on the basis of contaminant-specific soil chemical characteristics (i.e., Kd's, solubilities, and nonexchangeable sorbed fraction). Field cases are used to demonstrate the screening approach and to outline the primary considerations involved in accurately applying sequential extraction procedures to support the of MNA for site remediation. The results of these case studies provide strong evidence that site-specific screening and the use of sequential extraction procedures are effective methods for evaluating natural attenuation for metals impacted sites. 相似文献
960.
Reeve W O'Hara G Chain P Ardley J Bräu L Nandesena K Tiwari R Copeland A Nolan M Han C Brettin T Land M Ovchinikova G Ivanova N Mavromatis K Markowitz V Kyrpides N Melino V Denton M Yates R Howieson J 《Standards in genomic sciences》2010,2(3):347-356
Rhizobium leguminosarum bv trifolii is a soil-inhabiting bacterium that has the capacity to be an effective nitrogen fixing microsymbiont of a diverse range of annual Trifolium (clover) species. Strain WSM1325 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from root nodules collected in 1993 from the Greek Island of Serifos. WSM1325 is produced commercially in Australia as an inoculant for a broad range of annual clovers of Mediterranean origin due to its superior attributes of saprophytic competence, nitrogen fixation and acid-tolerance. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first completed genome sequence for a microsymbiont of annual clovers. We reveal that its genome size is 7,418,122 bp encoding 7,232 protein-coding genes and 61 RNA-only encoding genes. This multipartite genome contains 6 distinct replicons; a chromosome of size 4,767,043 bp and 5 plasmids of size 828,924 bp, 660,973 bp, 516,088 bp, 350,312 bp and 294,782 bp. 相似文献