Boykins RA  Buehler PW  Jia Y  Venable R  Alayash AI 《Proteins》2005,59(4):840-855

Reacting human deoxyHbA0 with oxidized raffinose (O-raffinose), a trisaccharide, results in a low oxygen affinity \"blood substitute,\" stabilized in a noncooperative T-conformation and possesses readily oxidizable rhombic heme. In this study, we fractionated the O-raffinose-modified HbA0 heterogeneous polymer (O-R-PolyHbA0) into six distinct fractions with a molecular weight distribution ranging from 64 to approximately 600 kDa using size-exclusion chromatography (SEC). Oxygen equilibrium and kinetics binding parameters of all fractions were nearly identical, reflecting a lack of heterogeneity in ligand binding properties among O-R-PolyHbA0 species (Hill coefficient n equal to 1.0). Several mass spectrometry techniques were used to evaluate undigested and digested HbA0, O-R-PolyHbA0, and O-R-PolyHbA0 fractions. Proposed sites of intramolecular crosslinking (i.e., beta1Lys82, beta2Lys82, and beta1Val1) were not found to be the predominant site of crosslinking within the central cavity. Intermolecular crosslinking with O-raffinose results in no discernible site of amino acids modifications with the exception of beta93Cys and alpha104Cys. Based on accessible surface area (ASA) calculations in intact deoxyHbA0, slight conformational changes are required to allow for the S on alpha104Cys to be modified during the reaction with O-raffinose or its partially oxidized product(s). The stabilization of HbA0 in the T-conformation may not be a direct correlate of O-raffinose induced changes, but an indirect consequence of changing hydration in the water-filled central cavity and/or the distal heme pocket leading in the latter case to accelerated iron oxidation. Structural data presented here when taken together with the oxidative instability of O-R-PolyHbA0 may provide some basis for the reported toxicity of this oxygen carrier.  相似文献   

    

Engin ahin 《Chirality》2019,31(10):892-897

Optically active aromatic alcohols are valuable chiral building blocks of many natural products and chiral drugs. Lactobacillus paracasei BD87E6, which was isolated from a cereal‐based fermented beverage, was shown as a biocatalyst for the bioreduction of 1‐(benzofuran‐2‐yl) ethanone to (S)‐1‐(benzofuran‐2‐yl) ethanol with highly stereoselectivity. The bioreduction conditions were optimized using L. paracasei BD87E6 to obtain high enantiomeric excess (ee) and conversion. After optimization of the bioreduction conditions, it was shown that the bioreduction of 1‐(benzofuran‐2‐yl)ethanone was performed in mild reaction conditions. The asymmetric bioreduction of the 1‐(benzofuran‐2‐yl)ethanone had reached 92% yield with ee of higher than 99.9% at 6.73 g of substrate. Our study gave the first example for enantiopure production of (S)‐1‐(benzofuran‐2‐yl)ethanol by a biological green method. This process is also scalable and has potential in application. In this study, a basic and novel whole‐cell mediated biocatalytic method was performed for the enantiopure production of (S)‐1‐(benzofuran‐2‐yl)ethanol in the aqueous medium, which empowered the synthesis of a precious chiral intermediary process to be converted into a sophisticated molecule for drug production.  相似文献   

    

OLIVIER PIERRE  GILBERT ENGLER  JULIE HOPKINS  FRÉDÉRIC BRAU  ERIC BONCOMPAGNI  DIDIER HÉROUART 《Plant, cell & environment》2013,36(11):2059-2070

Legumes form a symbiotic interaction with Rhizobiaceae bacteria, which differentiate into nitrogen‐fixing bacteroids within nodules. Here, we investigated in vivo the pH of the peribacteroid space (PBS) surrounding the bacteroid and pH variation throughout symbiosis. In vivo confocal microscopy investigations, using acidotropic probes, demonstrated the acidic state of the PBS. In planta analysis of nodule senescence induced by distinct biological processes drastically increased PBS pH in the N₂‐fixing zone (zone III). Therefore, the PBS acidification observed in mature bacteroids can be considered as a marker of bacteroid N₂ fixation. Using a pH‐sensitive ratiometric probe, PBS pH was measured in vivo during the whole symbiotic process. We showed a progressive acidification of the PBS from the bacteroid release up to the onset of N₂ fixation. Genetic and pharmacological approaches were conducted and led to disruption of the PBS acidification. Altogether, our findings shed light on the role of PBS pH of mature bacteroids in nodule functioning, providing new tools to monitor in vivo bacteroid physiology.  相似文献   

    

Andino LM  Takeda M  Kasahara H  Jakymiw A  Byrne BJ  Lewin AS 《The journal of gene medicine》2008,10(2):132-142

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《Animal : an international journal of animal bioscience》2013,7(10):1631-1639

Existing methods for estimating individual dairy cow energy balance typically either need information on feed intake, that is, the traditional input–output method, or frequent measurements of BW and body condition score (BCS), that is, the body reserve changes method (EB_body). The EB_body method holds the advantage of not requiring measurements of feed intake, which are difficult to obtain in practice. The present study aimed first to investigate whether the EB_body method can be simplified by basing EB_body on BW measurements alone, that is, removing the need for BCS measurements, and second to adapt the EB_body method for real-time use, thus turning it into a true on-farm tool. Data came from 77 cows (primiparous or multiparous, Danish Holstein, Red or Jersey) that took part in an experiment subjecting them to a planned change in concentrate intake during milking. BW was measured automatically during each milking and real-time smoothed using asymmetric double-exponential weighting and corrected for the weight of milk produced, gutfill and the growing conceptus. BCS assessed visually with 2-week intervals was also smoothed. EB_body was calculated from BW changes only, and in conjunction with BCS changes. A comparison of the increase in empty body weight (EBW) estimated from EB_body with EBW measured over the first 240 days in milk (DIM) for the mature cows showed that EB_body was robust to changes in the BCS coefficients, allowing functions for standard body protein change relative to DIM to be developed for breeds and parities. These standard body protein change functions allow EB_body to be estimated from frequent BW measurements alone, that is, in the absence of BCS measurements. Differences in EB_body levels before and after changes in concentrate intake were calculated to test the real-time functionality of the EB_body method. Results showed that significant EB_body increases could be detected 10 days after a 0.2 kg/day increase in concentrate intake. In conclusion, a real-time method for deriving EB_body from frequent BW measures either alone or in conjunction with BCS measures has been developed. This extends the applicability of the EB_body method, because real-time measures can be used for decision support and early intervention.  相似文献   

    

Reem A. Alajmi 《Saudi Journal of Biological Sciences》2019,26(1)

Fasciolosis is a parasitic disease of medical and economic importance. This retrospective study was conducted on 110 Fasciola flukes collected from livers of 14 infected Naimi sheep slaughtered at Riyadh abattoir in Saudi Arabia during winter season of 2016. Collected specimens were analyzed for their species identification on the basis of partial sequences of mitochondrial 28S rRNA gene. Results have shown the presence of both Fasciola hepatica (F. hepatica) and Fasciola gigantica (F. gigantica) species. Where Fasciola hepatica was predominate (80%). Both intra-species and interspecies genetic distance was studied and results showed that the intraspecific variability among individuals of both species i.e., F. hepatica and F. gigantica, ranging between 0 and 1% while the interspecific diversity between F. hepatica and F. gigantica was only 1%. In conclusion, mitochondrial 28S rRNA gene is a proved as a good marker in identifying Fasciola of different species. Where, the F. hepatica and F. gigantica are present in sheep breed in Riyadh region, Saudi Arabia.  相似文献   

    

Gardner BR  Strickland MJ  Correa A 《Birth defects research. Part A, Clinical and molecular teratology》2007,79(7):559-564

BACKGROUND: Although many birth defects surveillance programs incorporate georeferenced records into their databases, practical methods for routine spatial surveillance are lacking. We present a macroprogram written for the software package R designed for routine exploratory spatial analysis of birth defects data, the Automated Spatial Surveillance Program (ASSP), and present an application of this program using spina bifida prevalence data for metropolitan Atlanta. METHODS: Birth defects surveillance data were collected by the Metropolitan Atlanta Congenital Defects Program. We generated ASSP maps for two groups of years that correspond roughly to the periods before (1994-1998) and after (1999-2002) folic acid fortification of flour. ASSP maps display census tract-specific spina bifida prevalence, smoothed prevalence contours, and locations of statistically elevated prevalence. We used these maps to identify areas of elevated prevalence for spina bifida. RESULTS: We identified a large area of potential concern in the years following fortification of grains and cereals with folic acid. This area overlapped census tracts containing large numbers of Hispanic residents. CONCLUSIONS: The potential utility of ASSP for spatial disease monitoring was demonstrated by the identification of areas of high prevalence of spina bifida and may warrant further study and monitoring. We intend to further develop ASSP so that it becomes practical for routine spatial monitoring of birth defects.  相似文献   

    

SVEIN DALE 《Ibis》2011,153(3):573-580

Analyses of lifetime fitness in birds are typically based on estimates of breeding success, in particular the number of offspring fledged. Small and isolated bird populations often have a male‐skewed adult sex ratio, so that male lifetime productivity depends to a large degree on pairing success, but few studies have focused on patterns of lifetime pairing success. The Norwegian population of Ortolan Buntings Emberiza hortulana is strongly male‐skewed, such that in any year about half of all males are unpaired. Pairing success of first‐year males (16–44%) was significantly lower than for older males (52–89%). Lifetime pairing success was correlated with lifespan and was strongly skewed, with a majority of males being paired only once or never, and only 11% paired three or more times despite a stable lifetime annual survival rate of 63%. Males that were paired in one year were more likely to be paired the next year than males that were unpaired in the previous year. The shortage of females caused even the older males to have a substantial probability of becoming unpaired, and 49% of long‐lived males (known as adults for at least 4 years) were unpaired after years in which they were paired. Pairing success in the Ortolan Bunting therefore follows similar age‐related and lifetime patterns in breeding success documented in other species. However, even the older males ran a high risk of not being paired, contrasting with earlier distinctions between pre‐breeding and breeding lifespans. I discuss the importance of knowledge of pairing success for the management of endangered and declining populations.  相似文献   

    

Peracino B  Wagner C  Balest A  Balbo A  Pergolizzi B  Noegel AA  Steinert M  Bozzaro S 《Traffic (Copenhagen, Denmark)》2006,7(1):22-38

Dictyostelium amoebae are professional phagocytes, which ingest bacteria as the principal source of food. We have cloned the Dictyostelium homologue of human natural resistance-associated membrane protein 1 (Nramp1) [solute carrier family 11 member 1 (Slc11a1)], an endo-lysosomal membrane protein that confers on macrophages resistance to infection by a variety of intracellular bacteria and protozoa. The Dictyostelium Nramp1 gene encodes a protein of 53 kDa with 11 putative transmembrane domains. The Nramp1 gene is transcribed during the growth-phase and downregulated to barely detectable levels upon starvation. To gain insights into their intracellular localization, we fused Nramp1 or the vatB subunit of the V-H(+)ATPase with green fluorescent protein and expressed in cells. Green fluorescent protein-vatB was inserted in membranes of all acidic compartments and the contractile vacuole network and decorated macropinosomes and phagosomes. Green fluorescent protein-Nramp1 decorated macropinosomes and phagosomes, in addition to intracellular vesicular compartments positive for endosomal SNARE protein Vti1 or vacuolin, a marker of the exocytic pathway. Nramp1 disruption generated mutants that were more permissive hosts than wild-type cells for intracellular growth of Legionella pneumophila and Micobacterium avium. Nramp1 overexpression protected cells from L. pneumophila infection. Evidence is provided that Nramp1 transports metal cations out of the phagolysosome in an ATP-dependent process and that L. pneumophila and M. avium use different mechanisms to neutralize Nramp1 activity.  相似文献   

    

Jonathan G. Messer  Robin G. Hopkins  Deborah E. Kipp 《Journal of cellular biochemistry》2015,116(9):1857-1866

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