RESUMEN
There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many points in between. To date, attempts to analyse this variability within the framework generated by the study of thermal performance curves have been lacking. We tested if frequency distribution histograms of continuous body temperature measurements could provide a useful analogue to a thermal performance curve in endotherms. We provide examples from mammals displaying a range of thermoregulatory phenotypes, break down continuous core body temperature traces into various components (active and rest phase modes, spreads and skew) and compare these components to hypothetical performance curves. We did not find analogous patterns to ectotherm thermal performance curves, in either full datasets or by breaking body temperature values into more biologically relevant components. Most species had either bimodal or right-skewed (or both) distributions for both active and rest phase body temperatures, indicating a greater capacity for mammals to tolerate body temperatures elevated above the optimal temperatures than commonly assumed. We suggest that while core body temperature distributions may prove useful in generating optimal body temperatures for thermal performance studies and in various ecological applications, they may not be a good means of assessing the shape and breath of thermal performance in endotherms. We also urge researchers to move beyond only using mean body temperatures and to embrace the full variability in both active and resting temperatures in endotherms.
RESUMEN
Urbanisation is an important factor driving species and biodiversity decline. Although habitat alterations can be detrimental for species, studies have shown that many diurnal primates are able to adapt to novel environments. Little is known about the ability of nocturnal primates to survive within an urban environment. To increase our understanding on this topic, we present ad libitum observations on group movement and sociality from urban and rural populations of the African lesser bushbaby (Galago moholi) in South Africa from 2014-2018. Our data show considerable changes in the social dynamics within urban bushbaby populations. In contrast to rural individuals, which spent the majority of their activity period solitarily or in pairs, urban individuals displayed a larger degree of sociality throughout their active period, forming groups of up to ten individuals. Furthermore, urban individuals spent less time moving around, while increasing social (communication/pair-grooming), foraging and feeding behaviour. Urban individuals fed on a range of different anthropogenic and natural food sources (insects/tree gum/nectar) compared to their rural counterparts. In summary, urban bushbabies showed a large degree of behavioural plasticity, with changes in social dynamics and structure frequently observed. Such alterations in sociality, along with the ability to utilise different feeding resources, may explain the ability of the species to survive within a highly altered environment.
Asunto(s)
Conducta Animal , Oscuridad , Primates/fisiología , Conducta Social , Urbanización , Adaptación Biológica , Animales , Ritmo Circadiano , Ecosistema , Conducta Alimentaria , SudáfricaRESUMEN
BACKGROUND: The symptomatic patient showing a string sign or ulcerative stenosis of the internal carotid artery (ICA) is subject to a high risk of arterial thrombosis or persisting intracranial embolization during the waiting period before operative revascularization. PATIENTS AND METHODS: During one year 186 operative revascularization procedures of the ICA were performed on the symptomatic patient. 26 of them fulfilled the prophylactic urgency criteria: symptoms of the cerebrovascular insufficiency and a string sign or ulcerative stenosis of the ICA with ulceration greater than 2 mm in depth. These results were compared to the control group of the 157 procedures under elective circumstances. RESULTS: Mean clamping time of the urgency and the elective patients were 23.8 min vs. 24.5 min and operation time 50.1 min vs. 54.3 min. None of our urgency patients presented new neurological defects in the postoperative phase, while this occurred in 3.8% in the elective group. Mortality rate in the elective group was 2.7% and 0% in the urgency group. Furthermore, there were fewer local complications in the urgency group. CONCLUSION: The urgent indication for the desobliteration of the ICA showing a symptomatic string sign or ulcerative stenosis can be recommended. Early thrombosis or neurological defects during the waiting period may be prevented without increasing complication rates.
Asunto(s)
Estenosis Carotídea/cirugía , Infarto Cerebral/prevención & control , Urgencias Médicas , Endarterectomía Carotidea , Anciano , Arteria Carótida Interna/cirugía , Estenosis Carotídea/mortalidad , Infarto Cerebral/mortalidad , Procedimientos Quirúrgicos Electivos , Femenino , Alemania , Humanos , Masculino , Examen Neurológico , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/mortalidad , Factores de Riesgo , Resultado del TratamientoRESUMEN
A gene was cloned from Burkholderia cepacia DBO1 that is homologous with Escherichia coli cysH encoding 3'-phosphoadenylylsulfate (PAPS) reductase. The B. cepacia gene is the most recent addition to a growing list of cysH homologs from a diverse group of sulfate-assimilating bacteria whose products show greater homology to plant 5'-adenylylsulfate (APS) reductase than they do to E. coli CysH. The evidence reported here shows that the cysH from one of the species, Pseudomonas aeruginosa, encodes APS reductase. It is able to complement an E. coli cysH mutant and a cysC mutant, indicating that the enzyme is able to bypass PAPS, synthesized by the cysC product. Insertional knockout mutation of P. aeruginosa cysH produced cysteine auxotrophy, indicating its role in sulfate assimilation. Purified P. aeruginosa CysH expressed as a His-tagged recombinant protein is able to reduce APS, but not PAPS. The enzyme has a specific activity of 5.8 micromol. min(-1). mg of protein(-1) at pH 8.5 and 30 degrees C with thioredoxin supplied as an electron donor. APS reductase activity was detected in several bacterial species from which the novel type of cysH has been cloned, indicating that this enzyme may be widespread. Although an APS reductase from dissimilatory sulfate-reducing bacteria is known, it shows no structural or sequence homology with the assimilatory-type APS reductase reported here. The results suggest that the dissimilatory and assimilatory APS reductases evolved convergently.
Asunto(s)
Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Burkholderia cepacia/enzimología , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Adenosina Fosfosulfato/metabolismo , Secuencia de Aminoácidos , Bacterias/enzimología , Bacterias/genética , Burkholderia cepacia/genética , Escherichia coli/enzimología , Escherichia coli/genética , Evolución Molecular , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Datos de Secuencia Molecular , Oxidorreductasas/clasificación , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/genética , Homología de Secuencia de Aminoácido , Especificidad por Sustrato , Sulfatos/metabolismo , Sulfotransferasas/genética , Sulfotransferasas/metabolismoRESUMEN
OBJECTIVE: in 1996 we changed our treatment for stenosis of the internal carotid artery (ICA) from open thromboendarterectomy and PTFE-patch plasty (TEA) to eversion endarterectomy (EEA). DESIGN: retrospective study. METHODS: a total of 475 EEAs of the ICA were performed between 2/96 and 11/96. These results were compared to the results of TEA carried out between 2/94 and 11/94 (n=388). RESULTS: clamping and operation time were significantly shorter for EEA. Neurological complications included transient ischaemic attacks in 1. 0% in the EEA group versus 1.3% after TEA (p=0.72), minor strokes (0. 6% vs. 1.8%, p=0.10) and major strokes in 1.5% versus 1.1% (p=0.59). The rate of restenosis >50% was 2.5% after EEA and 10.2% after TEA. The only detectable difference of statistical significance in complication rates was in the lesions of the hypoglossal nerve (5.3% vs. 2.6%, p=0.04). CONCLUSIONS: EEA of the ICA is a safe procedure for carotid reconstruction with the additional advantages of short clamping time, possibility of simultaneous shortening of an elongated ICA, and no requirement for patching.
Asunto(s)
Implantación de Prótesis Vascular/métodos , Arteria Carótida Interna , Estenosis Carotídea/cirugía , Endarterectomía Carotidea/métodos , Trombectomía/métodos , Adulto , Anciano , Anciano de 80 o más Años , Angiografía de Substracción Digital , Materiales Biocompatibles , Velocidad del Flujo Sanguíneo , Arteria Carótida Interna/diagnóstico por imagen , Estenosis Carotídea/diagnóstico , Estenosis Carotídea/fisiopatología , Circulación Cerebrovascular , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Tereftalatos Polietilenos , Politetrafluoroetileno , Recurrencia , Estudios Retrospectivos , Técnicas de Sutura , Resultado del Tratamiento , Ultrasonografía Doppler en ColorRESUMEN
A systematic study of the homologous series of omega-aminoalkyl-agaroses revealed differences in the affinities of 6-hydroxy-D- and 6-hydroxy-L-nicotine oxidase. In contrast to supports with nonpolar alkyl chains, omega-aminoalkyl-agarose showed high affinity towards the L-specific enzyme, while the D-specific oxidase was bound most firmly by omega-aminododecyl-agarose. 6-Hydroxy-L-nicotine oxidase could be desorbed by 1.3M NaCl only in the presence of the substrate L-6-hydroxynicotine. Using the omega-aminoalkyl-agarose, a complete separation of the enantiozymes was accomplished and an efficient purification procedure for both oxidases established.
Asunto(s)
Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/aislamiento & purificación , Oxidorreductasas/aislamiento & purificación , Arthrobacter/enzimología , Cromatografía de Afinidad/métodos , Peso MolecularAsunto(s)
Galactosamina/toxicidad , Hígado/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Animales , Endotoxinas/toxicidad , Femenino , Hígado/metabolismo , Hígado/ultraestructura , Glucógeno Hepático/metabolismo , Organoides/ultraestructura , Oxidorreductasas/metabolismo , Ratas , Transaminasas/metabolismo , Nucleótidos de Uracilo/metabolismo , Uridina/farmacologíaRESUMEN
Isolated rat hepatocytes preserved for several hours their contents of ATP, CTP, GTP, UTP and UDPG. Leakage of intracellular and membrane-bound enzymes remained in the range observed with the isolated perfused rat liver. D-Galactosamine led to a rapid decrease of the UTP and UDPG contents while ATP and GTP levels remained unaffected. The sum of acid-soluble uracil nucleotides increased immediately after the addition of D-galactosamine, indicating release of the UTP-mediated feed-back inhibition of pyrimidine nucleotide de novo biosynthesis. Addition of uridine to a hepatocyte suspension resulted in a rapid increase in the levels of uridylate derivatives; the concentrations of UTP and UDPG, previously depleted by D-galactosamine, were restored within 1 h. Isolated hepatocytes appear suitable for studies on the pathogenic sequence of events elicited by D-galactosamine and on the regulation of pyrimidine biosynthesis.
Asunto(s)
Galactosamina/farmacología , Hígado/efectos de los fármacos , Ribonucleótidos/metabolismo , Uridina/farmacología , Adenosina Trifosfato/metabolismo , Animales , Permeabilidad de la Membrana Celular/efectos de los fármacos , Nucleótidos de Citosina/metabolismo , Retroalimentación , Femenino , Guanosina Trifosfato/metabolismo , Hígado/citología , Hígado/metabolismo , Ratas , Nucleótidos de Uracilo/metabolismo , Uridina Difosfato Glucosa/metabolismoRESUMEN
Bilateral intercollicular lesions in the chick abolish or depress notonly calling, but also those phases of behavior when calling would have been occurring. These include: long bouts of excited feeding immediately after food is made available;examining and pecking moving targets and novel objects; persistent scanning, and inhibitionof other behaviour in a novel environment. Deaf birds behave precisely like controls,so that possible auditory deficits are not involved. During calling phases significantvisual stimuli are treated as if they were startling or conspicuous. Conversely,continuousexamination of a stimulus causes calling to diminish or disappear even though responsecontinues; a brief period when the stimulus is not seen causes calling to begin againwhen it is once more perceived. In addition to the increased effectiveness of relevantvisual stimuli, motor facilitation is usual in calling phases, as is inhibition ofirrelevant responses. Emotioanl behaviour in man and other mammals is composed tocalling phases in the chick
Asunto(s)
Adenosina Trifosfato/fisiología , Gluconeogénesis/efectos de los fármacos , Lactatos/metabolismo , Hígado/metabolismo , Acetoacetatos/biosíntesis , Adenosina/farmacología , Adenosina Trifosfato/farmacología , Animales , Etionina/farmacología , Hidroxibutiratos/biosíntesis , Cinética , Hígado/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Perfusión , Ratas , Factores de Tiempo , Urea/biosíntesisRESUMEN
The site of feedback inhibition of the biosynthesis of pyrimidine nucleotides de novo was investigated in the isolated perfused rat liver. Hepatic uridine phosphate contents were specifically depleted by use of D-galactosamine. The effective activities of enzymes involved in the synthetic pathway were deduced from the rats of incorporation of labeled precursors into the acid-soluble uracil nucleotide pool and into some intermediates of the pathway. The labeling of hepatic urea was also monitored. When the uridine phosphate contents were less than 20% of controls, the incorporation of [14-C]-bicarbonate was stimulated about 20-fold. Label from [U-14C]oxaloacetate used as permeable precursor of intrace-lular aspartate was introduced into the uridylates to the same extent in normal and UTP-depleted livers. Similar results were obtained with labeled carbamoyl phosphate although the uptake of this compound by the liver was rather low. The lack of labeling of urea from exogenous carbamoyl phosphate does not indicate a free exchange of extra- and intramitochondrial carbamoyl phosphate. [ureido-14C]Ureidosuccinate produced in normal and D-galactosamine-treated livers almost identical labeling patterns of dihydroorotate, orotate and orotidine 5'-phosphate. The steady state concentrations of these intermediates were all below 15 nmol/g liver wet weight.