RESUMO
An experiment was conducted with laying hens to determine the AME(n) value of crude glycerol, a coproduct of biodiesel production. Crude glycerol (87% glycerol, 9% water, 0.03% methanol, 1.26% Na, and 3,625 kcal/kg of gross energy) was obtained from a commercial biodiesel production facility (Ag Processing Inc., Sergeant Bluff, IA). A total of forty-eight 40-wk-old laying hens (Hy-Line W-36) were placed in metabolic cages (2 hens/ cage) and given free access to the experimental diets. A corn and soybean meal-based basal diet (18% CP, 2,875 kcal/kg of AME(n), 4.51% Ca, 0.51% nonphytate P) was formulated with 15% glucose.H(2)O and 1% Celite. Four dietary treatments were created by substituting 0, 5, 10, or 15% crude glycerol for glucose.H(2)O (3,640 kcal/kg of AME(n)). After 7 d of dietary adaptation, excreta were collected twice daily for 3 d, freeze-dried, and analyzed for contents of DM, Kjeldahl N, acid-insoluble ash, and gross energy. Egg production was recorded daily, and eggs were collected on d 7 and 8 of the experiment for calculation of egg mass (egg production x egg weight). Feed consumption was measured over the 10-d experimental period. Egg-production data were analyzed by ANOVA with 4 treatments and 6 replications in a completely randomized experimental design. The AME(n) value of crude glycerol was estimated as the slope of the linear relationship between the inclusion rate of dietary crude glycerol and the glucose-corrected AME(n) value of the experimental diets. No significant treatment effects (P > 0.1) were apparent for egg-production rate (93.0%), egg weight (56.1 g), egg mass (52.2 g/d), or feed consumption (104 g/d). Linear regression analysis (P < 0.001, r(2) = 0.92, n = 24) revealed that the AME(n) value of the crude glycerol used in this study was 3,805 +/- 238 kcal/kg (mean +/- SEM; as-is basis) for laying hens.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Galinhas/metabolismo , Metabolismo Energético , Glicerol/metabolismo , Oviposição/fisiologia , Ração Animal , Animais , Ovos/análise , Feminino , Modelos LinearesRESUMO
Recent studies have proposed algal cultivation in urban wastewaters for the dual purpose of waste treatment and bioenergy production from the resulting biomass. This study proposes an enhancement to this approach that integrates cultivation of an acidophilic strain, Galdieria sulphuraria 5587.1, in a closed photobioreactor (PBR); hydrothermal liquefaction (HTL) of the wet algal biomass; and recirculation of the nutrient-rich aqueous product (AP) of HTL to the PBR to achieve higher biomass productivity than that could be achieved with raw wastewater. The premise is that recycling nutrients in the AP can maintain optimal C, N and P levels in the PBR to maximize biomass growth to increase energy returns. Growth studies on the test species validated growth on AP derived from HTL at temperatures from 180 to 300°C. Doubling N and P concentrations over normal levels in wastewater resulted in biomass productivity gains of 20-25% while N and P removal rates also doubled.
Assuntos
Biocombustíveis , Rodófitas/crescimento & desenvolvimento , Águas Residuárias , Biomassa , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Fotobiorreatores , Temperatura , Águas Residuárias/química , Águas Residuárias/microbiologia , Purificação da Água/instrumentação , Purificação da Água/métodosRESUMO
Nutrient removal from primary wastewater effluent was tested using Galdieria sulphuraria, an acidophilic and moderately thermophilic alga. Biomass yield recorded in this study (27.42g biomass per g nitrogen removed) is higher than the average reported in the literature (25.75g g(-1)) while, the theoretical yield estimated from the empirical molecular formula of algal biomass is 15.8g g(-1). Seven-day removal efficiencies were 88.3% for ammoniacal-nitrogen and 95.5% for phosphates; corresponding removal rates were 4.85 and 1.21mg L(-1)d(-1). Although these rates are lower than the average literature values for other strains (6.36 and 1.34mg L(-1)d(-1), respectively), potential advantages of G. sulphuraria for accomplishing energy-positive nutrient removal are highlighted. Feasibility of growing G. sulphuraria outdoors at densities higher than in high-rate oxidation ponds is also demonstrated.
Assuntos
Adaptação Fisiológica , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Rodófitas/metabolismo , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Biodegradação Ambiental , Biomassa , Cidades , Fotobiorreatores , Rodófitas/crescimento & desenvolvimento , Esgotos/química , TemperaturaRESUMO
This paper compares energy use for different pig production systems in Iowa, a leader in US swine production. Pig production systems include not only the growth and performance of the pigs, but also the supporting infrastructure of pig production. This supporting infrastructure includes swine housing, facility management, feedstuff provision, swine diets, and manure management. Six different facility type × diet formulation × cropping sequence scenarios were modeled and compared. The baseline system examined produces 15,600 pigs annually using confinement facilities and a corn-soybean cropping sequence. Diet formulations for the baseline system were corn-soybean meal diets that included the synthetic AA l-lysine and exogenous phytase. The baseline system represents the majority of current US pork production in the Upper Midwest, where most US swine are produced. This system was found to require 744.6 MJ per 136-kg market pig. An alternative system that uses bedded hoop barns for grow-finish pigs and gestating sows would require 3% less (720.8 MJ) energy per 136-kg market pig. When swine production systems were assessed, diet type and feed ingredient processing were the major influences on energy use, accounting for 61 and 79% of total energy in conventional and hoop barn-based systems, respectively. Improving feed efficiency and better matching the diet formulation with the thermal environment and genetic potential are thus key aspects of reducing energy use by pig production, particularly in a hoop barn-based system. The most energy-intensive aspect of provisioning pig feed is the production of synthetic N for crop production; thus, effectively recycling manure nutrients to cropland is another important avenue for future research. Almost 25% of energy use by a conventional farrow-to-finish pig production system is attributable to operation of the swine buildings. Developing strategies to minimize energy use for heating and ventilation of swine buildings while maintaining pig comfort and performance is a third critical area for future research. The hoop barn-based alternative uses 64% less energy to operate buildings but requires bedding and 2.4% more feed. Current Iowa pig production systems use energy differently but result in similar total energy use. Compared with 1975, current farrow-to-finish systems in Iowa require 80% less energy to produce live market pigs.
Assuntos
Criação de Animais Domésticos/economia , Criação de Animais Domésticos/métodos , Suínos , Poluentes Atmosféricos , Ração Animal , Animais , Dieta/veterinária , Efeito Estufa , Iowa , Esterco/análise , Modelos Teóricos , Nitrogênio/químicaRESUMO
Demand for nonsolar energy and concern about the implications of fossil fuel combustion have encouraged examination of energy use associated with agriculture. The United States is a global leader in pig production, and the United States swine industry is centered in Iowa. Feed is the largest individual input in pig production, but the energy consumption of the Iowa swine feed production chain has yet to be critically examined. This analysis examines nonsolar energy use and resulting 100-yr global warming potential (GWP) associated with the swine feed production chain, beginning with cultivation of crops and concluding with diet formulation. The nonsolar energy use and accompanying 100-yr GWP associated with production of 13 common swine feed ingredients are estimated. Two diet formulation strategies are considered for 4 crop sequence x ingredient choice combinations to generate 8 crop sequence x diet formulation scenarios. The first formulation strategy (simple) does not include synthetic AA or phytase. The second strategy (complex) reduces CP content of the diet by using L-lysine to meet standardized ileal digestibility lysine requirements of pigs and includes the exogenous enzyme phytase. Regardless of crop sequence x diet formulation scenario, including the enzyme phytase is energetically favorable and reduces the potential excretion of P by reducing or removing inorganic P from the complete diet. Including L-lysine reduces the CP content of the diet and requires less nonsolar energy to deliver adequate standardized ileal digestible lysine than simply feeding soybean meal. Replacing soybean meal with full-fat soybeans is not energetically beneficial under Iowa conditions. Swine diets including dried distillers grains with solubles and crude glycerol require approximately 50% more nonsolar energy inputs than corn-soybean meal diets or corn-soybean meal diets including oats. This study provides essential information on cultivation, processing, and manufacture of swine feed ingredients in Iowa that can be coupled with other models to estimate the nonsolar energy use and 100-yr GWP of pig production.
Assuntos
Ração Animal , Criação de Animais Domésticos , Conservação de Recursos Energéticos , Aquecimento Global , Suínos , Agricultura/normas , Ração Animal/normas , Criação de Animais Domésticos/normas , Animais , Avena , Dieta/veterinária , Efeito Estufa , Iowa , Glycine max , Zea maysRESUMO
Fungal-plant root associations involve nutrient exchanges, between the partners and the soil, particularly phosphate, that benefit both organisms. Discrete dynamical system (DDS) models are reconstructed to capture gene regulation in the arbuscular mycorrhizae Glomus versiforme-Medicago trunculata root symbiosis. Previously published time-course gene expression data derived from various days post-inoculation were clustered to identify genes co-regulated in mycorrhizal roots. Uncolonised roots grown with high phosphate provide a key nutritional control condition. First-order linear DDS models were created using a data-driven method to fit to the observed gene expression data. The result of the modelling constitutes active gene interactions in the regulatory network of the plant root at 8, 15, 22, 31 and 36 days post-inoculation. These genes are involved in basic metabolism, development, oxidative stress and defense pathways, and show consistent dynamic behaviours in the model. The functions of previously unannotated genes were further elucidated from the developed system maps.
Assuntos
Medicago truncatula/genética , Medicago truncatula/microbiologia , Modelos Genéticos , Micorrizas/genética , Simbiose/genética , Redes Reguladoras de Genes , Genes Fúngicos , Genes de Plantas , Medicago truncatula/metabolismo , Micorrizas/metabolismo , Fosfatos/metabolismo , Raízes de Plantas/microbiologia , Biologia de SistemasRESUMO
The apparent DE and ME values of crude glycerol for growing pigs were determined in 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility, which used soybean oil as the initial feedstock. Dietary treatments were 0, 5, or 10% glycerol addition to basal diets in Exp. 1; 0, 5, 10, or 20% glycerol addition to basal diets in Exp. 2; and 0 and 10% crude glycerol addition to the basal diets in Exp. 3, 4, and 5. Each diet was fed twice daily to pigs in individual metabolism crates. After a 10-d adjustment period, a 5-d balance trial was conducted. During the collection period, feces and urine were collected separately after each meal and stored at 0 degrees C until analyses. The GE of each dietary treatment and samples of urine and feces from each pig were determined by isoperibol bomb calorimetry. Digestible energy of the diet was calculated by subtracting fecal energy from the GE in the feed, whereas ME was calculated by subtracting the urinary energy from DE. The DE and ME values of crude glycerol were estimated as the slope of the linear relationship between either DE or ME intake from the experimental diet and feed intake. Among all experiments, the crude glycerol (86.95% glycerol) examined in this study was shown to have a DE of 3,344 +/- 8 kcal/kg and an ME of 3,207 +/- 10 kcal/kg, thereby providing a highly available energy source for growing pigs.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Metabolismo Energético/fisiologia , Glicerol/metabolismo , Suínos/metabolismo , Ração Animal/análise , Animais , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/metabolismo , Digestão/fisiologia , Feminino , Glicerol/administração & dosagem , Glicerol/análise , Masculino , Distribuição AleatóriaRESUMO
The effects of dietary crude glycerin on growth performance, carcass characteristics, meat quality indices, and tissue histology in growing pigs were determined in a 138-d feeding trial. Crude glycerin utilized in the trial contained 84.51% glycerin, 11.95% water, 2.91% sodium chloride, and 0.32% methanol. Eight days postweaning, 96 pigs (48 barrows and 48 gilts, average BW of 7.9 +/- 0.4 kg) were allotted to 24 pens (4 pigs/pen), with sex and BW balanced at the start of the experiment. Dietary treatments were 0, 5, and 10% crude glycerin inclusion in corn-soybean meal-based diets and were randomly assigned to pens. Diets were offered ad libitum in meal form and formulated to be equal in ME, sodium, chloride, and Lys, with other AA balanced on an ideal AA basis. Pigs and feeders were weighed every other week to determine ADG, ADFI, and G:F. At the end of the trial, all pigs were scanned using real-time ultrasound and subsequently slaughtered at a commercial abattoir. Blood samples were collected pretransport and at the time of slaughter for plasma metabolite analysis. In addition, kidney, liver, and eye tissues were collected for subsequent examination for lesions characteristic of methanol toxicity. After an overnight chilling of the carcass, loins were removed for meat quality, sensory evaluation, and fatty acid profile analysis. Pig growth, feed intake, and G:F were not affected by dietary treatment. Dietary treatment did not affect 10th-rib backfat, LM area, percent fat free lean, meat quality, or sensory evaluation. Loin ultimate pH was increased (P = 0.06) in pigs fed the 5 and 10% crude glycerin compared with pigs fed no crude glycerin (5.65 and 5.65 versus 5.57, respectively). Fatty acid profile of the LM was slightly changed by diet with the LM from pigs fed 10% crude glycerin having less linoleic acid (P < 0.01) and more eicosapentaenoic acid (P = 0.02) than pigs fed the 0 or 5% crude glycerin diets. Dietary treatment did not affect blood metabolites or frequency of lesions in the examined tissues. This experiment demonstrated that pigs can be fed up to 10% crude glycerin with no effect on pig performance, carcass composition, meat quality, or lesion scores.
Assuntos
Composição Corporal , Suplementos Nutricionais , Glicerol/administração & dosagem , Carne/normas , Suínos/fisiologia , Animais , Análise Química do Sangue , Ácidos Graxos/química , Feminino , Masculino , Músculo Esquelético/metabolismo , Suínos/crescimento & desenvolvimentoRESUMO
The effects of gestation housing systems on sow and litter performance were evaluated for 2.5 yr in southwest Iowa. Gestation housing system treatments were as follows: 1) individual gestation stalls in a mechanically ventilated confinement building with a partially slatted floor and a manure flush system and 2) group pens with individual feed stalls in deep-bedded, naturally ventilated hoop barns. In all, 957 litters from 353 sows were evaluated. Number of pigs born alive per litter differed for the 2 housing treatments (P = 0.002). Sows gestated in hoop barns gave birth to more live pigs per litter (10.0 +/- 0.2 pigs) than sows gestated in stalls (9.3 +/- 0.2 pigs). Preweaning mortality was not different for the 2 housing treatments (P = 0.70). Cross-fostering was done to equalize litter size within 24 h of birth, which resulted in an equal number of weaned pigs per sow (P = 0.50) regardless of gestation housing treatment. The weaning-to-breeding interval was different (P = 0.01), with sows kept in stalls (4.3 +/- 0.6 d) returning to estrus sooner than sows gestated in hoop barns (6.0 +/- 0.6 d). These results indicate that gestating sows can be housed as groups in deep-bedded hoop barns equipped with individual feeding stalls and will perform comparably to gestating sows housed in confinement systems with individual gestation stalls.
Assuntos
Abrigo para Animais , Suínos/fisiologia , Criação de Animais Domésticos , Animais , Feminino , GravidezRESUMO
After the broad industrialization of the US pork industry, there has been a development of niche markets for export and domestic pork; that is, there is a pork niche market phenomenon. The US pork niche market phenomenon is characterized, and 2 of the major markets are explained in detail. With the Midwest's tradition of a diversified family-based agriculture and record low hog prices of the late 1990s, the conditions were conducive for this phenomenon to develop. Pork niche markets utilize various sales methods including Internet sales, local abattoir sales, direct marketing, farmer networks, and targeting to organized groups. In 2003, there were approximately 35 to 40 active pork niche marketing efforts in Iowa. The Berkshire breed is an example of a swine breed that has had a recent resurgence because of niche markets. Berkshire pork is known for tenderness and excellent quality. Berkshire registrations have increased 4-fold in the last 10 yr. One of the larger niche marketers of "natural pork" is Niman Ranch Pork, which has more than 400 farmer-producers and processes about 2,500 pigs weekly. Many US consumers of pork are interested in issues concerning the environment, food safety, pig welfare, and pig farm ownership and structure. These consumers may be willing to pay more for pork from farmers who are also concerned about these issues. Small- and medium-sized swine farmers are active in pork niche markets. Niche markets claim product differentiation by superior or unique product quality and social attributes. Quality attributes include certain swine breeds, and meat quality, freshness, taste or flavor, and tenderness. Social or credence attributes often are claimed and include freedom from antibiotics and growth promotants; local family farm production; natural, organic, outdoor, or bedded rearing; humane rearing; known origin; environmentally friendly production; and the absence of animal by-products in the feed. Niche pork markets and alternative swine production practices offer an unusual contrast to commodity pork markets and industrial confinement swine production. Because they strive to have these attributes in their product, the niche pork market producers are a distinct clientele group. If niche pork markets continue to flourish, the markets and the producers that supply them will be a viable sector in a diverse US pork industry.
Assuntos
Indústria Alimentícia/economia , Marketing/economia , Carne/economia , Carne/provisão & distribuição , Animais , Carne/normas , Suínos , Estados UnidosRESUMO
Nitrogen (N) is known to be transferred from fungus to plant in the arbuscular mycorrhizal (AM) symbiosis, yet its metabolism, storage and transport are poorly understood. In vitro mycorrhizas of Glomus intra-radices and Ri T-DNA-transformed carrot roots were grown in two-compartment Petri dishes. (15)N- and/or (13)C-labeled substrates were supplied to either the fungal compartment or to separate dishes containing uncolonized roots. The levels and labeling of free amino acids (AAs) in the extra-radical mycelium (ERM) in mycorrhizal roots and in uncolonized roots were measured by gas chromatography/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Arginine (Arg) was the predominant free AA in the ERM, and almost all Arg molecules became labeled within 3 wk of supplying (15)NH(4) (+) to the fungal compartment. Labeling in Arg represented > 90% of the total (15)N in the free AAs of the ERM. [Guanido-2-(15)N]Arg taken up by the ERM and transported to the intra-radical mycelium (IRM) gave rise to (15)N-labeled AAs. [U-(13)C]Arg added to the fungal compartment did not produce any (13)C labeling of other AAs in the mycorrhizal root. Arg is the major form of N synthesized and stored in the ERM and transported to the IRM. However, NH(4) (+) is the most likely form of N transferred to host cells following its generation from Arg breakdown.
Assuntos
Daucus carota/microbiologia , Micorrizas/metabolismo , Nitrogênio/metabolismo , Aminoácidos/metabolismo , Transporte Biológico , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , SimbioseRESUMO
Dehydrins are a family of desiccation proteins that were identified originally in plants (T.J. Close, A.A. Kortt, P.M. Chandler [1989] Plant Mol Biol 13: 95-108; G. Galau, T.J. Close [1992] Plant Physiol 98: 1523-1525). Dehydrins are characterized by the consensus amino acid sequence domain EKKGIMDKIKEKLPG found at or near the carboxy terminus; the core of this domain (KIKEKLPG) may be repeated from one to many times within the complete polypeptide. Dehydrins generally accumulate in plants in response to dehydration stress, regardless of whether the stimulus is evaporation, chilling, or a decrease in external osmotic potential. Polyclonal antibodies highly specific to the consensus carboxy terminus of plant dehydrins were used to search for dehydrins in cyanobacteria, many of which are known to survive desiccation. A 40-kD osmotic-stress-induced protein was identified in Anabaena sp. strain PCC 7120. The 40-kD protein was usually not detected in logarithmic cultures and was induced by shifting the growth medium to higher solute concentrations. Several solutes have inductive effects, including sucrose, sorbitol, and polyethylene glycol (PEG). Measurements of osmotic potential suggest that a shift of -0.5 MPa (sucrose and PEG) or -1.2 MPa (sorbitol) is sufficient to induce synthesis of the 40-kD protein. Glycerol, which is highly permeable, was not an inducer at -1.2 MPa (0.5 M), nor was the plant hormone abscisic acid. Induction appears to be evoked by a shift in osmotic potential approximately equal in absolute magnitude to the expected turgor pressure of bacterial cells in logarithmic phase growth. A dehydrin-like polypeptide was also identified among osmotically induced proteins from two other filamentous, heterocyst-forming cyano-bacteria. A 40-kD protein was observed in Calothrix sp. strain PCC 7601, and in Nostoc sp. strain Mac-R2, an osmotic-induced doublet at 39 and 40 kD was observed. From these data, it appears that cyanobacteria produce a dehydrin-like protein under osmotic stress.
Assuntos
Proteínas de Bactérias/imunologia , Cianobactérias/imunologia , Proteínas de Plantas/imunologia , Plantas/imunologia , Sequência de Aminoácidos , Proteínas de Bactérias/química , Meios de Cultura , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/imunologia , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Pressão Osmótica , Proteínas de Plantas/química , TemperaturaRESUMO
The cyanobacterium Anabaena sp. strain ATCC 27898 was found to utilize the siderophore schizokinen to accumulate iron from the environment. This organism had previously been shown to produce schizokinen under low-iron conditions, and we observed that the iron-transport capability is also increased in response to iron limitation. Uptake activity was specific for ferric schizokinen displayed kinetics typical of a protein-mediated process with an apparent Km of 0.04 microM and saturation at high concentrations of substrate. Light-driven transport was blocked by uncouplers and by ATPase inhibitors. Transport in dark-adapted cells was additionally blocked by inhibitors of respiration. We conclude that ATP serves as an energy source for the cellular uptake of ferric schizokinen.
Assuntos
Cianobactérias/metabolismo , Ácidos Hidroxâmicos/metabolismo , Transporte Biológico Ativo/efeitos dos fármacos , Cianobactérias/crescimento & desenvolvimento , Compostos Férricos/metabolismo , Ferro/metabolismo , Cinética , Luz , Desacopladores/farmacologiaRESUMO
The nucleotide sequence of nifD, the structural gene for the alpha subunit of dinitrogenase from Anabaena 7120, has been determined. The coding sequence contains 1,440 nucleotides, which predict an amino acid sequence of 480 residues and M(r) of 54,283. The predicted sequence contains eight cysteines, of which five are conserved with respect to adjoining sequences and position relative to the alpha subunits of dinitrogenase from Azotobacter, Clostridium, and Klebsiella. Because there are also five conserved cysteines in the beta subunit of Anabaena dinitrogenase [Mazur, B. J. & Chiu, C.-F. (1982) Proc. Natl. Acad. Sci. USA 79, 6782-6786], the number of cysteine residues participating as ligands to FeS clusters is likely to be 20 per alpha(2)beta(2) tetramer. This number is sufficient to accommodate the known four Fe(4)S(4) clusters, leaving at least four cysteines to be shared among the two FeMo cofactors and the more poorly characterized two-iron center. Although the alpha- and beta-subunit gene sequences are not recognizably homologous, their secondary structures, predicted from the sequences, indicate similar domains around three of the conserved cysteine residues.
RESUMO
Vegetative cells of the cyanobacterium Anabaena contain an 11 kb DNA element within the coding region of the nifD gene. This element is excised by site-specific recombination between directly repeated 11 bp sequences at each of its ends during differentiation of nitrogen-fixing cells called heterocysts. Site-specific recombination, leading to the same rejoined nifD gene, was observed during propagation in E. coli of a fragment containing the 11 kb element and flanking sequences. An assay for excision of the element in E. coli was developed, based on mini-Mu-lac transposition into the element. Since the 11 kb element lacks an origin of replication, its excision results in loss of lac and conversion of blue colony-forming cells to white on X-gal plates. Insertion and deletion mutagenesis identified a region of the element needed for excision. Mutations in this region could be complemented by a 6 kb fragment containing an open reading frame that runs counter to those of the nif genes, beginning 240 bp from the recombination site.
Assuntos
Deleção Cromossômica , Cianobactérias/genética , Genes Reguladores , Sequência de Bases , Elementos de DNA Transponíveis , Escherichia coli/genética , Mutação , Plasmídeos , Recombinação GenéticaRESUMO
A cDNA containing the entire coding region for the iron storage protein ferritin has been isolated from the French bean plant, Phaseolus vulgaris L. cv. Tendergreen. Ferritin protein was purified from young leaves and shoot meristem tissue and used to raise antisera in mice. A lambda gt11 cDNA library was constructed from seed-derived poly(A)+ RNA, and screened with the mouse anti-ferritin serum. A 1.2 kb immunopositive phage DNA insert was isolated and sequenced. The derived amino acid sequence shows substantial similarity with other ferritin sequences. The 5' untranslated region contains two out-of-frame AUG codons, a region of extreme pyrimidine composition bias and potentially stable secondary structure.
Assuntos
DNA , Fabaceae/genética , Ferritinas/genética , Proteínas de Plantas/genética , Plantas Medicinais , Sequência de Aminoácidos , Sequência de Bases , Ferritinas/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas de Plantas/metabolismo , Alinhamento de Sequência , Glycine max/genéticaRESUMO
A 10-year-old girl with a malignant ovarian germ cell tumor was treated with cis-platinum-based chemotherapy. During the third and fourth courses of therapy, the patient developed hyponatremia, hypomagnesemia, and hypocalcemia. Renal sodium wasting was documented to be the cause of the hyponatremia. Despite normalization of serum electrolytes, hyponatremia again occurred during a period of stress following cessation of cis-platinum. Prior work has documented that cis-platinum-induced hypomagnesemia is related to renal tubular dysfunction with resulting magnesium wasting. A similar etiology for cis-platinum-induced hyponatremia and renal sodium wasting is proposed.
Assuntos
Cisplatino/efeitos adversos , Hiponatremia/induzido quimicamente , Cálcio/sangue , Criança , Feminino , Humanos , Túbulos Renais/efeitos dos fármacos , Magnésio/sangue , Neoplasias Ovarianas/tratamento farmacológico , Sódio/sangue , Teratoma/tratamento farmacológicoRESUMO
The amino acid sequence of hemerythrin from the sipunculid worm, Themiste dyscritum, was determined by sequenator analyses of the S-pyridylethylated protein and fragments derived by further chemical and enzymatic cleavages. The fragments were obtained by cleavage of the intact protein with hydroxylamine, trypsin digestion of citraconylated intact protein, and subdigestion with Staphylococcal protease V8. The COOH-terminal sequence was determined using carboxypeptidases A and B and amino acid analyses. The polypeptide chain was found to contain 113 amino acids. Since heterogeneity was observed at no more than two positions in the amino acid sequence, the native octameric protein appears to be composed of identical subunits. By combining information derived from sequence analyses and x-ray crystallographic studies, it has been possible to identify amino acids responsible for the tertiary and quaternary structure of the protein as well as amino acids serving as iron ligands at the oxygen-binding site.
Assuntos
Anelídeos/análise , Hemeritrina , Metaloproteínas , Sequência de Aminoácidos , Animais , Fragmentos de Peptídeos/análise , Especificidade da EspécieRESUMO
An 11-kbp DNA element of unknown function interrupts the nifD gene in vegetative cells of Anabaena sp. strain PCC 7120. In developing heterocysts the nifD element excises from the chromosome via site-specific recombination between short repeat sequences that flank the element. The nucleotide sequence of the nifH-proximal half of the element was determined to elucidate the genetic potential of the element. Four open reading frames with the same relative orientation as the nifD element-encoded xisA gene were identified in the sequenced region. Each of the open reading frames was preceded by a reasonable ribosome-binding site and had biased codon utilization preferences consistent with low levels of expression. Open reading frame 3 was highly homologous with three cytochrome P-450 omega-hydroxylase proteins and showed regional homology to functionally significant domains common to the cytochrome P-450 superfamily. The sequence encoding open reading frame 2 was the most highly conserved portion of the sequenced region based on heterologous hybridization experiments with three genera of heterocystous cyanobacteria.
Assuntos
Cianobactérias/genética , Genes Bacterianos , Fixação de Nitrogênio/genética , Sequência de Aminoácidos , Sequência de Bases , Southern Blotting , Códon , Sistema Enzimático do Citocromo P-450/genética , Genes , Dados de Sequência Molecular , Mapeamento por RestriçãoRESUMO
Anabaena sp. strain 6411, which produces the dihydroxamate siderophore schizokinen to facilitate iron uptake, is also capable of using the related siderophore aerobactin. The two siderophores compete for the same iron transport system, but there is a markedly higher affinity for ferric schizokinen than for ferric aerobactin. The trihydroxamate siderophore ferrioxamine B is far less effective as an iron donor in this organism. Anabaena sp. strain 7120 appears to be closely related to strain 6411. It synthesizes schizokinen as its major siderophore and shows rates of iron uptake from ferric schizokinen, ferric aerobactin, and ferrioxamine B which are similar to those observed with strain 6411. Anabaena cylindrica Lemm. 7122 and 1611, on the other hand, differ from strain 6411. In contrast to schizokinen, the hydroxamate which they produce in response to iron starvation cannot be extracted with water from the organic layer and does not support the growth of the siderophore auxotroph Arthrobacter flavescens JG-9. Strain 7122 can use its endogenous siderophore or schizokinen to promote iron uptake, but at 50-fold-lower rates than are observed with Anabaena sp. strain 6411 or 7120.