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1.
J Vet Cardiol ; 43: 1-9, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35870399

RESUMEN

OBJECTIVE: The aim of this paper is to evaluate owners' chronic medication adherence for management of feline cardiovascular disease in the small animal referral setting. ANIMALS, MATERIALS AND METHODS: A questionnaire-based study of owners at five multispecialty, small animal referral centers was conducted. Owners completed a written survey evaluating demographics, degree of medication adherence, and difficulties encountered for medication adherence. Owners were free to decline participation in the study. RESULTS: Fifty-four questionnaires were available for review. The most common diagnosis was hypertrophic cardiomyopathy (n = 31, 57.4%). Clopidogrel was the most cited medication that was difficult to administer consistently (n = 13, 24.0%) although twenty owners (37.0%) reported no difficulty consistently administering medications. "Taste of medication" (n = 14, 25.9%) was the most reported reason for difficulty medicating their cat, and most owners (n = 36, 66.7%) stated twice daily was the highest frequency of heart medications they feel they can consistently administer. Fifty owners (92.6%) met the criteria for medication adherence. CONCLUSIONS: Chronic medication adherence in this study population was high. Clopidogrel was the most difficult medication to consistently administer, and twice a day dosing was the highest frequency of medication administration most owners could achieve. Cardiologists should be aware of these factors when determining optimal treatment protocols for the management of cardiovascular disease in cats.


Asunto(s)
Enfermedades Cardiovasculares , Enfermedades de los Gatos , Gatos , Animales , Propiedad , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/veterinaria , Clopidogrel/uso terapéutico , Encuestas y Cuestionarios , Cumplimiento de la Medicación , Derivación y Consulta , Enfermedades de los Gatos/tratamiento farmacológico
2.
J Vet Cardiol ; 37: 42-51, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34537674

RESUMEN

OBJECTIVE: To evaluate owners' medication adherence for management of cardiovascular disease in the small animal specialty setting. ANIMALS, MATERIALS, AND METHODS: A questionnaire-based study of owners at a single, multispecialty, small animal referral center was conducted. Owners completed a written survey evaluating demographics, degree of medication adherence, and difficulties encountered for medication adherence. Owners were free to decline participation in the study. RESULTS: Ninety-six questionnaires were completed during the study period. Fifty-four respondents (56.3%) reported treating their pet for over one year for cardiovascular disease, and myxomatous mitral valve disease was the most common diagnosis (76.0%). Twenty-nine (30.2%) respondents felt they could consistently administer a maximum of three medications daily, and 46 (47.9%) respondents reported twice-daily dosing was the highest frequency of administration that could be consistently achieved. Twenty-two respondents (22.9%) reported that their pet required daily medications for at least one other chronic condition besides cardiac disease. Seventeen respondents (17.7%) reported at least occasionally missing medications, although only one (1.0%) reported it was more than 20% of medications per week. CONCLUSIONS: Medication adherence was high in this study population. Almost one-half of owners surveyed reported being unable to consistently administer more than three medications daily, and approximately one-quarter of patients were treated for at least one additional chronic condition requiring daily medications, in addition to cardiac disease. Clinicians should be aware of these factors when determining optimal treatment protocols for the management of cardiovascular disease in dogs.


Asunto(s)
Enfermedades Cardiovasculares , Enfermedades de los Perros , Animales , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/veterinaria , Enfermedades de los Perros/tratamiento farmacológico , Perros , Cumplimiento de la Medicación , Derivación y Consulta , Encuestas y Cuestionarios
5.
J Small Anim Pract ; 53(6): 357-60, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22647214

RESUMEN

A nine-year-old neutered female mixed breed dog presented for evaluation following a five-day history of lethargy, inappetence, weakness, abdominal distension and generalised muscle atrophy. Persistent vatrial standstill with a junctional rhythm was identified on electrocardiogram. Echocardiogram identified moderate dilation of all cardiac chambers and mild thickening of the mitral and tricuspid valves. Serology was negative for Neospora caninum and Toxoplasma gondii. Permanent pacemaker implantation was performed in addition to endomyocardial and skeletal muscle biopsies. Cryosections from the biceps femoris muscle showed numerous nemaline rod bodies while endomyocardial biopsies were possibly consistent with end-stage myocarditis. Rod bodies have rarely been reported in the veterinary literature. To the authors' knowledge, this is the first report of adult-onset nemaline rod myopathy and hypothyroidism with concurrent cardiac disease in a dog.


Asunto(s)
Enfermedades de los Perros/diagnóstico , Hipotiroidismo/veterinaria , Cuerpos de Inclusión/patología , Fibras Musculares Esqueléticas/patología , Miocarditis/veterinaria , Miopatías Nemalínicas/veterinaria , Animales , Enfermedades de los Perros/cirugía , Perros , Electromiografía/métodos , Femenino , Hipotiroidismo/diagnóstico , Miocarditis/diagnóstico , Miopatías Nemalínicas/diagnóstico , Miopatías Nemalínicas/cirugía , Marcapaso Artificial/veterinaria
6.
Appl Microbiol Biotechnol ; 82(1): 25-39, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19082586

RESUMEN

Olive-mill wastes are produced by the industry of olive oil production, which is a very important economic activity, particularly for Spain, Italy and Greece, leading to a large environmental problem of current concern in the Mediterranean basin. There is as yet no accepted treatment method for all the wastes generated during olive oil production, mainly due to technical and economical limitations but also the scattered nature of olive mills across the Mediterranean basin. The production of virgin olive oil is expanding worldwide, which will lead to even larger amounts of olive-mill waste, unless new treatment and valorisation technologies are devised. These are encouraged by the trend of current environmental policies, which favour protocols that include valorisation of the waste. This makes biological treatments of particular interest. Thus, research into different biodegradation options for olive-mill wastes and the development of new bioremediation technologies and/or strategies, as well as the valorisation of microbial biotechnology, are all currently needed. This review, whilst presenting a general overview, focus critically on the most significant recent advances in the various types of biological treatments, the bioremediation technology most commonly applied and the valorisation options, which together will form the pillar for future developments within this field.


Asunto(s)
Monitoreo del Ambiente/métodos , Hongos/metabolismo , Residuos Industriales/análisis , Olea/metabolismo , Aguas del Alcantarillado/microbiología , Aerobiosis , Anaerobiosis , Biodegradación Ambiental , Biotransformación
7.
J Small Anim Pract ; 49(7): 349-55, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18638059

RESUMEN

A five-month-old female Jack Russell terrier was presented for investigation of acute lethargy, anorexia, coughing, respiratory distress and weakness. Examination findings included cyanosis, a grade 3 of 6 systolic heart murmur and prolonged capillary refill time. Radiography and echocardiography revealed severe pulmonary hypertension, cor pulmonale and right-sided heart failure. Indirect measurement of the systolic pulmonary artery pressure estimated pressures over 100 mmHg. Despite treatment the patient died. Post-mortem examination did not identify a congenital cardiovascular anomaly. Histopathology confirmed acute necrotising pulmonary arteritis and immunohistochemistry failed to identify any immune complex or complement deposition.


Asunto(s)
Enfermedades de los Perros/patología , Hipertensión Pulmonar/veterinaria , Necrosis/veterinaria , Vasculitis/veterinaria , Enfermedad Aguda , Animales , Ansiolíticos/uso terapéutico , Perros , Resultado Fatal , Femenino , Furosemida/uso terapéutico , Verapamilo/uso terapéutico
8.
Appl Microbiol Biotechnol ; 79(2): 309-17, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18347793

RESUMEN

Two-phase olive mill waste (TPOMW) is a semisolid effluent that is rich in contaminating polyphenols and is produced in large amounts by the industry of olive oil production. Laboratory-scale bioreactors were used to investigate the biodegradation of TPOMW by its indigenous microbiota. The effect of nutrient addition (inorganic N and P) and aeration of the bioreactors was studied. Microbial changes were investigated by PCR-temperature time gradient electrophoresis (TTGE) and following the dynamics of polar lipid fatty acids (PLFA). The greatest decrease in the polyphenolic and organic matter contents of bioreactors was concomitant with an increase in the PLFA fungal/bacterial ratio. Amplicon sequences of nuclear ribosomal internal transcribed spacer region (ITS) and 16S rDNA allowed identification of fungal and bacterial types, respectively, by comparative DNA sequence analyses. Predominant fungi identified included members of the genera Penicillium, Candida, Geotrichum, Pichia, Cladosporium, and Aschochyta. A total of 14 bacterial genera were detected, with a dominance of organisms that have previously been associated with plant material. Overall, this work highlights that indigenous microbiota within the bioreactors through stimulation of the fungal fraction, is able to degrade the polyphenolic content without the inoculation of specific microorganisms.


Asunto(s)
Bacterias/metabolismo , Biodegradación Ambiental , Hongos/metabolismo , Olea/química , Eliminación de Residuos Líquidos/métodos , Bacterias/genética , Bacterias/crecimiento & desarrollo , Reactores Biológicos , Flavonoides/metabolismo , Residuos Industriales , Olea/metabolismo , Fenoles/metabolismo , Polifenoles
9.
Aust Vet J ; 85(12): 487-94, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18042154

RESUMEN

BACKGROUND: Non-radioactive assay methods are widely used in commercial laboratories to measure canine blood cortisol concentrations, despite a paucity of published validity data of these tests compared with the traditional 'gold standard' radioimmunoassay. OBJECTIVES: To compare a commercial chemiluminescence assay with radioimmunoassay for blood cortisol measurement, determine the effect of storage on the radioimmunoassay, and determine the impact of any differences on clinical decisions. METHODS: The study included 54 client owned dogs undergoing adrenal function testing. Fresh plasma or serum samples (n=170) were assayed for cortisol using radioimmunoassay (RIA1). Samples (n=196) were also frozen and stored in batches, and assayed by chemiluminescence and radioimmunoassay (RIA2). RESULTS: Overall, there was a strong correlation (r2=0.967, P<0.001) between RIA2 and chemiluminescence concentrations without significant difference between means. Strong correlations were present for RIA2 and chemiluminescence at concentration subgroups of >400 nmol/L (r2=0.869, P<0.001), <100 nmol/L (r2=0.790, P<0.001), and <40 nmol/L (r2=0.738, P<0.001). Significant differences between means were present for RIA2 and chemiluminescence concentrations in the <100 nmol/L, and <40 nmol/L (P<0.001) groups. Despite a significant difference in RIA1 and RIA2 results overall, there was no significant difference between RIA1 and RIA2 for any of the concentration groups. In seven cases, discrepant RIA2 and chemiluminescence results may have altered clinical decisions. CONCLUSIONS: Although RIA and chemiluminescence cortisol concentrations appear highly correlated, a significant difference may exist for concentrations less than 100 nmol/L in stored canine sera. Results of chemiluminescence cortisol assays should be interpreted with caution unless the specific assay method in the laboratory has been adequately validated in dogs.


Asunto(s)
Hiperfunción de las Glándulas Suprarrenales/veterinaria , Conservación de la Sangre/veterinaria , Enfermedades de los Perros/sangre , Hidrocortisona/sangre , Mediciones Luminiscentes/veterinaria , Radioinmunoensayo/veterinaria , Hiperfunción de las Glándulas Suprarrenales/sangre , Hiperfunción de las Glándulas Suprarrenales/diagnóstico , Hormona Adrenocorticotrópica/farmacología , Animales , Conservación de la Sangre/métodos , Conservación de la Sangre/normas , Recolección de Muestras de Sangre/métodos , Recolección de Muestras de Sangre/normas , Recolección de Muestras de Sangre/veterinaria , Enfermedades de los Perros/diagnóstico , Perros , Relación Dosis-Respuesta a Droga , Mediciones Luminiscentes/métodos , Radioinmunoensayo/métodos , Valores de Referencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de Tiempo
10.
Aust Vet J ; 84(8): 285-90, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16911229

RESUMEN

OBJECTIVE: To evaluate the clinico-pathological findings, response to treatment and prevalence of complications in dogs with primary hypoparathyroidism. DESIGN: Retrospective study of 17 dogs presenting to the University of Melbourne Veterinary Clinical Centre and Murdoch University Veterinary Hospital over a 15 year period (1990 to 2004). Case records were evaluated for signalment, body weight, diet type, historical and clinical findings, serum total calcium, phosphate, albumin and parathyroid hormone concentrations, urinary fractional excretion ratios of calcium and phosphate, electrocardiogram (ECG) results, treatments administered, outcome and period of follow-up. RESULTS: The most common breeds identified were St Bernard (three dogs), Chihuahua (two dogs), German Shepherd (two dogs) and Jack Russell Terrier (two dogs). Three dogs were cross bred. Seizures, muscle tremors and fasciculations, stiff gait, tetany, muscle cramping, behavioural change and hyperventilation were the most common clinical signs. Vomiting, inappetence, diarrhoea, abdominal pain, hyperthermia, facial pruritus, ataxia, weakness, cataracts, and circling also occurred with less frequency. The mean duration of observed clinical signs preceding diagnosis was 33 days (median 13 days, range 1 to 173 days). All dogs had marked hypocalcaemia with normal or mildly increased serum albumin concentrations. Mean phosphate concentrations were significantly higher in inappetent dogs (P = 0.049). Mean serum calcium concentrations were significantly lower in dogs with cataracts compared to those without (P = 0.046). There were no other significant relationships between serum calcium or phosphate concentrations and the clinical presentation or outcome. No significant correlations were identified between the presence of a particular clinical sign and the duration of clinical signs. ECGs were obtained in four dogs and all exhibited QT interval prolongation due to a ST-segment prolongation. Sixteen of 17 dogs were treated successfully for hypocalcaemia and discharged from hospital. Acute management included parenteral calcium gluconate (10 dogs) and intravenous anticonvulsants (five dogs). Chronic therapy included oral vitamin D analogues and calcium supplementation. Treatment complications occurred in two dogs and included acute renal failure (one dog) and iatrogenic tissue necrosis following subcutaneous calcium administration (one dog). The mean follow-up period was 14.5 months (median 13 months, range 0 to 39 months). Twelve dogs were alive at the last follow up and two dogs were euthanased for unrelated reasons. The type of vitamin D analogue used was not associated with outcome. CONCLUSION: Primary hypoparathyroidism was an uncommon diagnosis in dogs. Saint Bernards, cross bred dogs, German Shepherd dogs and Terrier breeds were most commonly affected. Neurological signs were the most common presenting clinical signs, although alimentary signs may have been more common than previously reported. Dogs with primary hypoparathyroidism appeared to have a good prognosis following initiation of calcium supplementation and vitamin D therapy. Complications of treatment were uncommon and could be minimised with regular monitoring.


Asunto(s)
Calcio/sangre , Enfermedades de los Perros/diagnóstico , Hipoparatiroidismo/veterinaria , Hormona Paratiroidea/sangre , Fosfatos/sangre , Animales , Cruzamiento , Calcio/uso terapéutico , Calcio/orina , Enfermedades de los Perros/sangre , Enfermedades de los Perros/tratamiento farmacológico , Enfermedades de los Perros/patología , Perros , Electrocardiografía/veterinaria , Femenino , Hipocalcemia/tratamiento farmacológico , Hipocalcemia/etiología , Hipocalcemia/veterinaria , Hipoparatiroidismo/sangre , Hipoparatiroidismo/complicaciones , Hipoparatiroidismo/diagnóstico , Masculino , Fosfatos/orina , Estudios Retrospectivos , Albúmina Sérica/análisis , Resultado del Tratamiento , Vitamina D/uso terapéutico
11.
Aust Vet J ; 84(1-2): 22-9, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16498830

RESUMEN

Death adder envenomation is rare in humans and there is only one brief report previously in dogs. This paper details three cases of canine common death adder (Acanthophis antarcticus) envenomation and one case of bardick (Echiopsis curta) envenomation which were responsive to death adder antivenom. The available literature on death adder envenomations is also reviewed. The main clinical sign in the four dogs was severe lower motor neuron paralysis. There was no clinical evidence of coagulopathy or myopathy. Use of a snake venom detection kit was essential for selection of appropriate antivenom. Death adder and bardick envenomation in dogs potentially has a good prognosis if sufficient antivenom is administered and intensive supportive care is available.


Asunto(s)
Antivenenos/uso terapéutico , Venenos Elapídicos/antagonistas & inhibidores , Venenos Elapídicos/envenenamiento , Mordeduras de Serpientes/veterinaria , Animales , Australia , Femenino , Masculino , Pronóstico , Juego de Reactivos para Diagnóstico , Mordeduras de Serpientes/terapia , Especificidad de la Especie , Resultado del Tratamiento
12.
Int J Syst Evol Microbiol ; 51(Pt 3): 1161-1170, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11414268

RESUMEN

A novel Gram-positive, obligately alkaliphilic, non-sporulating, rod-shaped, flagellated bacterium is described. Three different strains of the bacterium were isolated from the wash-waters of edible-olive production. The strains are motile, psychrotolerant, halotolerant, facultatively anaerobic bacteria with a pH optimum of 9.0-9.4 for two strains and 9.8-10.2 for the third. They are catalase- and oxidase-negative. A range of hexoses and some disaccharides composed of hexoses, but not pentoses are metabolized by the bacterial strains: D(+)-glucose, D(+)-glucose 6-phosphate, D(+)-cellobiose, starch or sucrose are the carbohydrates best utilized. No common amino acids are utilized by the three alkaliphilic strains, but yeast extract can serve as sole carbon and energy source. The major membrane phospholipids are diphosphatidylglycerol, phosphatidylglycerol and an unknown phospholipid, all containing saturated and unsaturated, even-carbon-numbered fatty acyl chains with hexadecanoic and hexadecen(7)oic as the predominant components. The G+C content of the DNA in all three strains is 39.7+/-1.0 mol% and the DNA relatedness by hybridization is >88% for all pairings of the three strains. The results of 16S rRNA sequence comparisons revealed that the strains represent a new alkaliphilic linkage in the order Bacillales, belonging to the Carnobacterium/Aerococcus-like spectrum. It is proposed that the strains should be assigned to a new genus and species, Alkalibacterium olivoapovliticus. The three strains, designated WW2-SN4aT, WW2-SN4c and WW2-SN5, have been deposited with Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) as DSM 13175T, DSM 12937 and DSM 12938 respectively, and in the National Collection of Industrial and Marine Bacteria as NCIMB 13710T, NCIMB 13711 and NCIMB 13712, respectively. The type species of this genus is Alkalibacterium olivoapovliticus and the type strain is WW2-SN4aT.


Asunto(s)
Lactobacillaceae/clasificación , Filogenia , Plantas Comestibles/microbiología , Anaerobiosis , Antibacterianos/farmacología , Secuencia de Bases , ADN Ribosómico/genética , Manipulación de Alimentos , Lactobacillaceae/genética , Lactobacillaceae/aislamiento & purificación , Lactobacillaceae/ultraestructura , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Fosfolípidos/análisis , ARN Bacteriano/química , ARN Bacteriano/genética , ARN Ribosómico 16S/química , ARN Ribosómico 16S/genética
13.
Extremophiles ; 4(4): 201-8, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10972188

RESUMEN

A novel Gram-positive facultatively alkaliphilic, sporulating, rod-shaped bacterium, designated as WW3-SN6, has been isolated from the alkaline washwaters derived from the preparation of edible olives. The bacterium is nonmotile, and flagella are not observed. It is oxidase positive and catalase negative. The facultative alkaliphile grows from pH 7.0 to 10.5, with a broad optimum from pH 8.0 to 9.0. It could grow in up to 15% (w/v) NaCl, and over the temperature range from 4 degrees to 37 degrees C, with an optimum between 27 degrees and 32 degrees C: therefore, it is both halotolerant and psychrotolerant. The bacterium is sensitive to a range of beta-lactam, sulfonamide, and aminoglycoside antibiotics, but resistant to trimethoprim. The range of amino acids, sugars, and polyols utilized as growth substrates indicates that this alkaliphile is a heterotrophic bacterium. D(+)-glucose, D(+)-glucose-6-phosphate, D(+)-cellobiose, starch, or sucrose are the substrates best utilized. The major membrane lipids are phosphatidylglycerol and diphosphatidylglycerol, with smaller amounts of phosphatidylethanolamine and an unknown phospholipid. During growth at high pH, the proportion of phosphatidylglycerol is increased relative to phosphatidylethanolamine. The fatty acyl components in the membrane phospholipids are mainly branched chain, with 13-methyl tetradecanoic and 12-methyl tetradecanoic acids as the predominant components. The G + C content of the genomic DNA is 41.1 +/- 1.0 mol%. The results of 16S ribosomal RNA sequence analysis place this alkaliphilic bacterium in a cluster, together with an unnamed alkaliphilic Bacillus species (98.2% similarity).


Asunto(s)
Bacillus/aislamiento & purificación , Frutas/microbiología , Álcalis , Bacillus/química , Bacillus/citología , Bacillus/genética , Composición de Base , División Celular , ADN Ribosómico/análisis , ADN Ribosómico/genética , Concentración de Iones de Hidrógeno , Lípidos/análisis , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Temperatura
14.
Extremophiles ; 4(2): 83-90, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10805562

RESUMEN

Despite the fact that a much greater proportion of the earth environment is cold rather than hot, much less is known about psychrophilic, cold-adapted microorganisms compared with thermophiles living at high temperatures. In particular, investigation of the molecular basis of cold-active enzymes from psychrophiles has only recently received concerted research attention, in measure as a result of the EC-funded project COLDZYME. This research effort has been stimulated by the realization that such cold-active enzymes offer novel opportunities for biotechnological exploitation. Only very recently has the first cold-active enzyme, alpha-amylase, been crystallized, and this success was followed rapidly by others. This effort has facilitated a direct approach to solving the three-dimensional structure of cold-active enzymes to complement the gene homology modeling that had been performed previously. Recently studies have highlighted how different adaptations are used by different enzymes to achieve conformational flexibility at low temperatures, and how such adaptations are not necessarily the opposite of those that confer thermostability to proteins in thermophilic counterparts. This review also highlights initial successes in engineering genetically improved thermal stability in cold-active enzymes to give improved catalysts for low-temperature biotechnology.


Asunto(s)
Archaea/enzimología , Bacterias/enzimología , Proteínas Bacterianas/metabolismo , Frío , Microbiología Industrial/métodos , Adaptación Fisiológica , Archaea/genética , Bacterias/genética , Proteínas Bacterianas/genética , Citrato (si)-Sintasa/química , Citrato (si)-Sintasa/metabolismo , Enzimas/genética , Enzimas/metabolismo , L-Lactato Deshidrogenasa/química , L-Lactato Deshidrogenasa/metabolismo , Malato Deshidrogenasa/química , Malato Deshidrogenasa/metabolismo , Estructura Terciaria de Proteína , Triosa-Fosfato Isomerasa/química , Triosa-Fosfato Isomerasa/metabolismo , alfa-Amilasas/química , alfa-Amilasas/metabolismo
15.
Extremophiles ; 4(2): 123-30, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10805567

RESUMEN

The first structural analysis of elongation factor G (EF-G) from a cold-adapted bacterium is presented. EF-G is an essential protein involved in the elongation process during protein synthesis and is therefore thought to play a crucial role in the low-temperature adaptation of cold-adapted microorganisms. To define its importance, the EF-G gene (fus) from the psychrotolerant bacterium Arthrobacter globiformis SI55 was cloned and sequenced. The deduced primary structure of the elongation factor is composed of 700 amino acids with a predicted molecular mass of 77.4 kDa. A three-dimensional model of the protein was constructed based on the known crystal structures of structurally homologous proteins. Structural features that might potentially be important for activity and flexibility at low temperature were deduced by comparisons with models of the EF-G proteins from the closely related mesophiles Micrococcus luteus and Mycobacterium tuberculosis. These features include a loss in the number of salt bridges in intradomain and interdomain positions, increased solvent interactions mediated by greater charge and polarity on domain surfaces, loop insertions, loss of proline residues in loop structures, and an increase of hydrophobicity in core regions. Specific changes have also been identified in the catalytic domain (G domain) and sites of potential ribosome interaction, which may directly affect guanosine triphosphate (GTP) hydrolysis and elongation rates at low temperature.


Asunto(s)
Secuencia de Aminoácidos/genética , Arthrobacter/genética , Proteínas Bacterianas/genética , Clima Frío , Factor G de Elongación Peptídica/genética , Proteínas Bacterianas/química , Micrococcus luteus/genética , Modelos Moleculares , Datos de Secuencia Molecular , Mycobacterium tuberculosis/genética , Factor G de Elongación Peptídica/química , Estructura Terciaria de Proteína , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad
16.
Int J Food Microbiol ; 55(1-3): 133-6, 2000 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-10791731

RESUMEN

Salmonella typhimurium (CRA 1005) was more sensitive than Listeria monocytogenes (NCTC 11994) to pulsed high electric field (PHEF) treatment in distilled water (10, 15 and 20 kV/cm), 10 mM tris-maleate buffer pH 7.4 (15 kV/cm) and model beef broth (0.75% w/v: 15 kV/cm). Sublethal injury could not be detected using a selective medium plating technique, indicating that bacterial inactivation by PHEF may be an 'all-or-nothing' event. PHEF-induced membrane permeabilization resulted in increased UV-leakage and a decreased ability of L. monocytogenes to maintain a pH gradient.


Asunto(s)
Manipulación de Alimentos , Microbiología de Alimentos , Listeria monocytogenes/crecimiento & desarrollo , Salmonella typhimurium/crecimiento & desarrollo , Membrana Celular , Recuento de Colonia Microbiana , Electricidad , Concentración de Iones de Hidrógeno
17.
Int J Food Microbiol ; 48(1): 1-10, 1999 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-10375130

RESUMEN

Salmonella typhimurium (CRA 1005) was more sensitive than Listeria monocytogenes (NCTC 11994) to pulsed high electric field (PHEF) treatment in distilled water (10, 15 and 20 kV/cm), 10 mM Tris-maleate buffer, pH 7.4 (15 kV/cm) and model beef broth (0.75%, w/v; 15 kV/cm). Sublethal injury could not be detected using a selective medium plating technique, indicating that bacterial inactivation by PHEF may be an 'all or nothing' event. PHEF-induced membrane permeabilisation resulted in an increase in the leakage of UV-absorbing material from the bacteria (UV-leakage) and a decreased ability of L. monocytogenes to maintain a pH gradient. A lack of correlation between the inhibition of H+-ATPase activity and PHEF treatment, cell viability or UV-leakage indicates that this enzyme is probably not a primary site of bacterial inactivation despite its role in the maintenance of internal pH.


Asunto(s)
Electricidad , Microbiología de Alimentos , Listeria monocytogenes/crecimiento & desarrollo , Salmonella typhimurium/crecimiento & desarrollo , Membrana Celular/enzimología , Membrana Celular/fisiología , Permeabilidad de la Membrana Celular/fisiología , Recuento de Colonia Microbiana , Fluoresceínas/química , Colorantes Fluorescentes/química , Concentración de Iones de Hidrógeno , Listeria monocytogenes/enzimología , Listeria monocytogenes/fisiología , Listeriosis/prevención & control , Fosfatos/análisis , Fosfatos/metabolismo , ATPasas de Translocación de Protón/análisis , Intoxicación Alimentaria por Salmonella/prevención & control , Salmonella typhimurium/enzimología , Salmonella typhimurium/fisiología , Espectrometría de Fluorescencia
18.
Acta Crystallogr D Biol Crystallogr ; 54(Pt 5): 1012-3, 1998 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-9757123

RESUMEN

Recombinant citrate synthase from a psychrotolerant bacterium, DS2-3R, recently isolated in Antarctica, has been crystallized. The crystals belong to space group P6122 or P6522, with cell dimensions a = b = 70.8, c = 307.8 A. Diffraction data collected on a synchrotron from a cryoprotected crystal extends to at least 2.0 A. Knowledge of the structure of this enzyme will add to the understanding of cold activity and thermolability, and will be of biotechnological interest. Previously, the structure of citrate synthase from Archaea inhabiting environments at 328 and 373 K, has been reported. This present study will extend our understanding of the structural integrity and activity of proteins at the temperature extremes of life.


Asunto(s)
Bacterias/enzimología , Proteínas Bacterianas/química , Citrato (si)-Sintasa/química , Conformación Proteica , Adaptación Fisiológica , Regiones Antárticas , Proteínas Bacterianas/aislamiento & purificación , Citrato (si)-Sintasa/aislamiento & purificación , Cristalización , Cristalografía por Rayos X , Congelación , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/aislamiento & purificación
19.
Artículo en Inglés | MEDLINE | ID: mdl-9670796

RESUMEN

Bacteria which live in cold conditions are known as psychrophiles. Since so much of our planet is generally cold, i.e. below 5 degrees C, it is not surprising that they are very common amongst a wide variety of habitats. To enable them to survive and grow in cold environments, psychrophilic bacteria have evolved a complex range of adaptations to all of their cellular components, including their membranes, energy-generating systems, protein synthesis machinery, biodegradative enzymes and the components responsible for nutrient uptake. Whilst such a systems approach to the topic has its advantages, all of the changes can be described in terms of adaptive alterations in the proteins and lipids of the bacterial cell. The present review adopts the latter approach and, following a brief consideration of the definition of psychrophiles and description of their habitats, focuses on those adaptive changes in proteins and lipids, especially those which are either currently being explored for their biotechnological potential or might be so in the future. Such applications for proteins range from the use of cold-active enzymes in the detergent and food industries, in specific biotransformations and environmental bioremediations, to specialised uses in contact lens cleaning fluids and reducing the lactose content of milk; ice-nucleating proteins have potential uses in the manufacture of ice cream or artificial snow; for lipids, the uses include dietary supplements in the form of polyunsaturated fatty acids from some Antarctic marine psychrophiles.


Asunto(s)
Bacterias/química , Fenómenos Fisiológicos Bacterianos , Biotecnología/tendencias , Proteínas Bacterianas/química , Frío , Enzimas/química , Genotipo , Lípidos/química , Fenotipo , Microbiología del Agua
20.
Int J Food Microbiol ; 40(3): 159-67, 1998 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-9620123

RESUMEN

A non-proteolytic strain of Clostridium botulinum (NCIB 4270) was found to have a complex lipid composition, comprising five major phosphorus-containing lipids: phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylserine (PS) and a glycophospholipid of unknown structure (GPL), in order of abundance. Changing the growth temperature did not alter the lipid composition either qualitatively or quantitatively. The main fatty acyl components of the lipids are 14:0, 16:0 and 16:1. When the growth temperature was lowered from 37 to 8 degrees C, there was an increase in 14:0 from 16.4 to 37.5%, an increase in 16:1 from 10.5 to 22.5%, and a decrease in the proportion of 16:0 from 40.3 to 19.1%. There was also a decrease in the proportion of cyclopropane fatty acids (15:0cyc and 17:0cyc) from 7.3 to 0.5%, and in the equivalent chain length of the total fatty acids from 15.9 to 15.3 as the temperature was lowered. The same temperature-dependent changes occurred in the five major lipid classes examined. Despite reports of the presence of plasmalogenic forms of phospholipids (i.e. those lipids which have the acyl chain in the sn-1 position replaced by an alk-1-enyl group) in some Clostridium spp., none were detected in C. botulinum NCIB 4270 using either commercially available spray reagents or by gas-liquid chromatographic analysis of the products or acid methanolysis of total lipid extracts. It is concluded that non-proteolytic C. botulinum lacks plasmalogens, typical of other clostridia, in its membranes and instead modulates its fatty acid composition in response to temperature changes in a manner that is typical of other (non-clostridial) bacteria.


Asunto(s)
Clostridium botulinum/crecimiento & desarrollo , Ácidos Grasos/biosíntesis , Microbiología de Alimentos , Fosfolípidos/biosíntesis , Cromatografía de Gases , Cromatografía en Capa Delgada , Clostridium botulinum/química , Ácidos Grasos/análisis , Hidrogenación , Fosfatidiletanolaminas/análisis , Fosfatidiletanolaminas/biosíntesis , Fosfatidilgliceroles/análisis , Fosfatidilgliceroles/biosíntesis , Fosfatidilserinas/análisis , Fosfatidilserinas/biosíntesis , Fosfolípidos/análisis , Plasmalógenos/análisis , Plasmalógenos/biosíntesis , Temperatura
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