RESUMO
Hematological and blood biochemistry values are useful in assessing the physiological, nutritional, and overall health status of captive and free-living wildlife. For the chimango caracara (Milvago chimango), the most common raptor species in Argentina, reference intervals (RIs) for hematology and blood biochemistry are lacking. For this study, 86 chimango caracaras were captured and studied in Mar del Plata and neighboring areas (Buenos Aires, Argentina) during winter (April-July) in 2018 and 2019. This is the first study to present RIs for 33 blood parameters in a large number of free-living chimango caracaras during the nonbreeding season. In addition, the variability of blood parameters according to sex and calendar year was analyzed. Overall, values for the studied parameters were similar to those described for other raptor species. There were significant differences between years for absolute monocyte counts, relative eosinophils, monocyte counts, glucose, phosphorus, and alanine aminotransferase. Only the relative count of eosinophils, aspartate aminotransferase, and calcium showed significant differences between the sexes. The values of absolute monocyte counts and the relative count of eosinophils and monocytes, glucose, phosphorus, and alanine aminotransferase were higher in 2019 than in 2018, whereas mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were higher in 2018. Relative eosinophil counts were higher for males than for females, and aspartate aminotransferase activity and calcium concentration were significantly higher for females than for males. The RIs for hematology and plasma biochemistry from this large number of chimango caracaras is of clinical relevance not only for chimango caracaras under medical care in rehabilitation centers but also in ecological studies aimed to investigate the physiological responses of this species to natural and anthropogenic changes.
Assuntos
Falconiformes , Hematologia , Aves Predatórias , Feminino , Masculino , Animais , Cálcio , Alanina Transaminase , Falconiformes/fisiologia , Glucose , Fósforo , Aspartato Aminotransferases , Valores de ReferênciaRESUMO
Innovative behavior is considered one of the main factors facilitating the adaptation of animals to urban life. However, the relationship between urbanization and innovativeness is equivocal, perhaps reflecting aspects of urban environments that influence differently the behavioural traits underlying the occurrence of an innovation. In this work, we analysed the variation in innovative problem-solving performance between urban and rural individuals of the Caracara Chimango (Milvago chimango), with the goal of determining which behavioural trait (or combination) most explained such variation. We found that urban raptors outperformed rural ones in their solving speed and solving level (number of solutions) with a multiaccess box. They also showed more persistence, motor flexibility and diversity, as well as higher effectiveness in their solving attempts than rural chimangos. Sex was not an important factor. Urban chimangos showed less neophobia and spent more time exploring the box than rural birds during the initial habituation period, which probably determined the amount of information about the system that each individual had at the beginning of first problem solving trial. This difference in novelty response both directly and indirectly, through its relationship with persistence, motor flexibility and proportion of effective attempts, explained variability in solving performance. All individuals showed a decrease in solving latency, and an increase in solving level with experience, indicating that learning occurred in both raptor groups. This improvement occurred in parallel with changes in the afore-mentioned traits, though the pattern of improvement differed between urban and rural chimangos. We suggest that the characteristics of urban areas modulate the novelty response of chimangos, along with other correlated non-cognitive behavioural traits, which act in combination to increase the chances that novel problems could be quickly solved, and the resulting new behaviours established in city populations of this species.
Assuntos
Falconiformes , Aves Predatórias , Animais , Aves , Criatividade , Ecossistema , Resolução de Problemas/fisiologiaRESUMO
Innovation, a process that plays an important role in the ecology and evolution of species, is considered an expression of behavioral flexibility in animals. Here we analyzed innovative problem-solving ability and performance enhancement through learning in the Olrog's Gull (Larus atlanticus), under controlled processes and experimental conditions. Trials were undertaken with nine adult individuals captured at a highly urbanized coastal area of Argentina. Each individual was presented with a Plexiglas box that could be opened by pushing or pulling two lids, each lid leading to a separated food reward. We measured problem-solving ability through consumption latency and the number of solved lids. As explanatory variables, we measured contact rate, as a measure of persistence, and the number of effective contacts. The results showed that the contact rate and effective contacts did not affect variables related to problem-solving ability during the first confrontation of the individuals with the closed box. Consumption latency decreased significantly throughout the trials, and with increasing contact rate and effective contacts. The number of solved lids increased through the trials independently of the contact rate and the total effective contacts with the box. Although persistence did not influence individuals' performance during the problem-solving test; this variable affected individuals' ability to solve the task throughout trials. Learning was evidenced by the decrease in the resolution time across experiments, suggesting that successful individuals improved their performance probably through a trial-and-error process. Evaluation of behavioral responses of a threatened seabird to a novel problem-solving task adds knowledge to previous field studies and provides a better understanding of the ability of individuals to adjust their foraging behavior in highly urbanized areas used during the non-breeding season.
Assuntos
Charadriiformes , Animais , Argentina , Criatividade , Espécies em Perigo de Extinção , Resolução de ProblemasRESUMO
PURPOSE: The aim of our study is to evaluate the number and the features of admissions to the emergency room (ER) requiring psychiatric consultation, in the period between May 4th and August 31st 2020. METHODS: We carried out a retrospective longitudinal observational study examining the 4 months following the initial lockdown imposed during the COVID-19 outbreak (May 4th and August 31st 2020). More specifically, the ER admissions leading to psychiatric referral were reviewed at all seven public hospitals of AUSL Romagna (Emilia Romagna region, Italy). Socio-demographic variables, history of medical comorbidities or psychiatric disorders, reason for ER admission, psychiatric diagnosis at discharge, and actions taken by the psychiatrist were collected. RESULTS: An 11.3% (p = 0.007) increase in psychiatric assessments was observed when compared with the same period of the previous year (2019). A positive personal history of psychiatric disorders (OR:0.68, CI: 0.53-0.87) and assessments leading to no indication for follow-up (OR: 0.22, CI: 0.13-0.39) were significantly less frequent, while there was a significant increase of cases featuring organic comorbidities (OR: 1.24, CI: 1.00-1.52) and suicidal ideation/self-harm/suicide attempt (OR: 1,71, CI: 1.19-2.45) or psychomotor agitation (OR: 1.46, CI: 1.02-2.07) as reason for admission. CONCLUSIONS: Our results showed an increase in ER psychiatric consultations compared to the previous year, underlying the increased psychological distress caused by the lockdown.
Assuntos
COVID-19 , COVID-19/epidemiologia , Controle de Doenças Transmissíveis , Serviço Hospitalar de Emergência , Humanos , Itália/epidemiologia , Pandemias , Estudos RetrospectivosRESUMO
In an ever-changing environment, the ability to adapt choices to new conditions is essential for daily living and ultimately, for survival. Behavioural flexibility allows animals to maximise survival and reproduction in novel settings by adjusting their behaviour based on specific information and feedback acquired in their current environments. However, a growing body of evidence indicates that an individual's personality type can limit the extent to which the individual might behave flexibly, by influencing the way an individual pays attention to novelty and how much information it collects and stores, which in turn affects the individual's decision-making and learning process. In this study, the behavioural flexibility of a generalist predator, the Chimango Caracara, Milvago chimango, was analysed using the reversal learning paradigm, focusing on the comparison between age classes, and the relation of learning flexibility with a personality trait, the level of neophobia. Due to the low number of male individuals captured, this study was carried out only with female birds. The results showed that age had no significant effect either on the acquisition of a stimulus-reward association, or on the capacity of reversing this previously learned association. Reversal of the response was a harder task for these birds in comparison with the initial acquisition process. The individual's performances in the learning tasks seemed to be uncorrelated with each other, suggesting that they involve different neural mechanisms. Contrary to the general pattern observed in the majority of previous work on personality and cognition in non-human animals, the level of neophobia did not correlate with the initial associative learning performance in both adults and juveniles, yet it showed a significant negative relationship with reversal learning ability, mainly in the regressive phase of this task, for the two age classes. Our results suggest that the predatory and generalist lifestyle of female individuals of M. chimango along with the selective pressures of the environment of the individuals studied might play a critical role in the degree and direction of the linkage between novelty response and learning flexibility observed in this study.
Assuntos
Falconiformes , Reversão de Aprendizagem , Recompensa , Animais , Aves , Cognição , Feminino , MasculinoRESUMO
Exploration represents an important way by which organisms evaluate environment information. The decision of whether or not an animal should investigate environmental changes may influence the extent to which animals learn about their surroundings and cope with habitat modifications. We analysed exploration behaviour in a suburban population of a raptor species, the Chimango Caracara, Milvago chimango, by examining how age, previous experience and object complexity influence novel object exploration. Our findings showed that object complexity did not influence caracaras initial approach and contact with objects, but did influence the degree of engagement during exploratory activities, as measured by total exploration time and number of exploration events. These variables were higher for complex objects than for simple objects. Experience resulted in less exploration of simple objects. It is likely that, for caracaras, simple objects are easier to encode and recall than complex objects, so additional exploration of such objects would not provide further information. Results suggest that exploratory behaviour in this raptor was guided more by the benefits of a greater quantity of information obtained by exploring complex objects, than by the risks associated to this activity. We can conclude that caracaras cope with novel features in their surroundings with a novelty-seeking strategy, characteristic for generalist species in discovering early new resources opportunities, and which might be a determining factor for adaptive responses to environment modification.
Assuntos
Comportamento Exploratório , Falconiformes , Fatores Etários , Animais , Estimulação LuminosaRESUMO
Innovation (i.e., a new solution to a familiar problem, or applying an existing behavior to a novel problem1,2) plays a fundamental role in species' ecology and evolution. It can be a useful measure for cross-group comparisons of behavioral and cognitive flexibility and a proxy for general intelligence.3,4,5 Among birds, experimental studies of innovation (and cognition more generally) are largely from captive corvids and parrots,6,7,8,9,10,11,12 though we lack serious models for avian technical intelligence outside these taxa. Striated caracaras (Phalcoboenus australis) are Falconiformes, sister clade to parrots and passerines,13,14,15 and those endemic to the Falkland Islands (Malvinas) show curiosity and neophilia similar to notoriously neophilic kea parrots16,17 and face similar socio-ecological pressures to corvids and parrots.18,19 We tested wild striated caracaras as a new avian model for technical cognition and innovation using a field-applicable 8-task comparative paradigm (adapted from Rössler et al.20 and Auersperg et al.21). The setup allowed us to assess behavior, rate, and flexibility of problem solving over repeated exposure in a natural setting. Like other generalist species with low neophobia,21,22 we predicted caracaras to demonstrate a haptic approach to solving tasks, flexibly switching to new, unsolved problems and improving their performance over time. Striated caracaras performed comparably to tool-using parrots,20 nearly reaching ceiling levels of innovation in few trials, repeatedly and flexibly solving tasks, and rapidly learning. We attribute our findings to the birds' ecology, including geographic restriction, resource unpredictability, and opportunistic generalism,23,24,25 and encourage future work investigating their cognitive abilities in the wild. VIDEO ABSTRACT.
Assuntos
Falconiformes , Papagaios , Animais , Resolução de Problemas , Cognição , AprendizagemRESUMO
BACKGROUND: Obsessions, compulsions, and stereotypes are common psychopathological manifestations of obsessive-compulsive, psychotic, and autism spectrum disorders (ASDs). These nosological entities may be present in comorbidity, with relevant clinical difficulties in the differential diagnosis process. Moreover, ASDs are a complex group of disorders, with a childhood onset, which also persist into adulthood and present heterogeneous symptom patterns that could be confused with psychotic disorders. METHODS AND RESULTS: We report a case of a 21-year-old man characterized by sexual and doubt obsessions; disorganized, bizarre, and stereotyped behaviors and compulsions; and social withdrawal, inadequate social skills, visual dispersions, and hypersensitivity to light stimuli. Obsessive and compulsive features were initially included within the differential diagnosis of psychotic and obsessive-compulsive spectrum disorders. However, aforementioned psychopathological elements did not improve when multiple antipsychotic drugs (olanzapine, haloperidol, and lurasidone) were administered in the hypothesis of schizophrenia and even worsened with clozapine therapy at a dose of 100 mg/d. Obsessions and compulsions progressively reduced during the fluvoxamine 14-week treatment paradigm at a dose of 200 mg/d. Considering the persistent deficits in social communication and interactions as well as the restricted interests pattern, a differential diagnostic hypothesis of ASD was formulated, and it was then confirmed at the final evaluation at a third-level health care center. CONCLUSIONS: We discuss similarities and differences in the psychopathology of obsessions, compulsions, and stereotypes in the previously mentioned disorders, to underline factors that can help in the differential diagnosis of similar cases, and consequently in the appropriateness of treatment choice.
RESUMO
Animal innovations have far-reaching ecological and evolutionary consequences. The occurrence and persistence of an innovation require several processes, including exploration, social and asocial learning, and low neophobia. In addition, the identity of the innovator may determine how these new behaviours are socially transmitted. Taking into account inter-individual and age differences, we investigated three correlates of animal innovation: object exploration, neophobia level and novel problem-solving ability in an opportunistic generalist raptor, the Chimango Caracara (Milvago chimango). Eighteen individuals (7 adults and 11 juveniles) were caught during the non-breeding period and housed in individual cages in outdoor aviaries. Each bird was given three tests: exploration, neophobia and problem-solving. Individuals differed in their response to novel situations both within and between age groups. Most of the juveniles were more explorative and had a lower neophobic response to a strange object than adult birds, but both age groups were able to solve a novel problem when given a food reward. In juveniles, neophobia level and problem-solving performance were inversely related; however, we found no relationship between these behaviours in adults. Exploration did not correlate with neophobia or problem-solving ability for either age group. This research is one of the few studies exploring the inter-individual and age differences in behavioural innovation and their correlates in a bird of prey. The explorative tendency, low neophobia and ability to innovate showed by M. chimango may be advantageous for this generalist and opportunistic raptor and might be some of the factors underlying its ecological success.
Assuntos
Comportamento Exploratório , Falconiformes , Resolução de Problemas , Fatores Etários , Animais , Comportamento Alimentar/psicologia , IndividualidadeRESUMO
Urban areas expose wildlife to an array of novel predators, amongst which, humans and dogs are highly frequent. Thus, wild animals living in urban areas are forced to invest more time and energy in defence behaviours, which depend on how the risk is perceived and assessed. We experimentally tested whether Burrowing owls coming from rural and urban habitats showed differences in behavioural responses when facing humans and domestic dogs. We measured flight initiation distances (FIDs), nest returning, and aggressiveness level when owls faced a human and a human with a dog walking towards them. Our results showed that urban owls recognise a human with a dog as a greater threat than a human alone, thus indicating that fear of domestic animals should be considered as affecting owls' settlement in cities and towns. On the other hand, rural owls perceived human and dogs as similar threats, but showed higher FIDs, less aggressiveness, and lower tendency to return to the nest than urban owls in both treatments. These findings emphasize the importance of modified habitats in modelling the response of urban and rural owls to predators and represent another step in the explanation of how wild animals assess and respond to threats associated with living in urbanized environments.
Assuntos
Comportamento Animal/fisiologia , Ecossistema , Comportamento Predatório/fisiologia , Percepção Social , Estrigiformes/fisiologia , Agressão/psicologia , Animais , Animais Selvagens , Cães , Medo/fisiologia , Humanos , Masculino , População Rural , População UrbanaRESUMO
Drosocin and apidaecin Ib are two insect antimicrobial peptides showing a significant sequence homology and a common mechanism of action, which includes stereoselective elements but is devoid of any pore-forming activity. A substantial difference between the two peptides is the presence in the drosocin sequence of an O-glycosylated threonine residue, which is important for its antimicrobial activity. Through the synthesis of a series of differently glycosylated drosocin analogues, we have shown that the antimicrobial activity against several Gram-negative bacteria appears to be modulated by the sugar moiety (Gal vs GalNAc) and the type of glycosidic linkage (alpha-O-, beta-O-, or alpha-C-). The insertion of a glycosylated threonine residue in the apidaecin Ib sequence improves the sequence homology with drosocin but reduces the antimicrobial activity. To gain information on the possible bioactive conformation of these peptides, we synthesized an unglycosylated cyclic analogue of drosocin, containing an intrachain disulfide bond, and the head-to-tail cyclic analogues of drosocin and apidaecin, as well as their corresponding cyclic dimers. Only the large cyclic dimer of apidaecin partially retained the antimicrobial activity, suggesting that a bending of the peptide chain, in particular in the middle of the molecule, is not a structural element characteristic of the bioactive conformation of drosocin and apidaecin. Experiments aimed at testing the effect of selected drosocin and apidaecin peptides on biological membranes showed that some peptides display a moderate hemolytic activity and that a dissociation between antibacterial activity and cytotoxicity to eukaryotic cells can be achieved in differently glycosylated peptide analogues.
Assuntos
Antibacterianos/síntese química , Peptídeos Catiônicos Antimicrobianos/síntese química , Glicopeptídeos/síntese química , Proteínas de Insetos/síntese química , Peptídeos Cíclicos/síntese química , Sequência de Aminoácidos , Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Dicroísmo Circular , Glicopeptídeos/química , Glicopeptídeos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/ultraestrutura , Proteínas de Insetos/química , Proteínas de Insetos/farmacologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Fosfolipídeos/química , Relação Estrutura-AtividadeRESUMO
BACKGROUND: To determine the repeatability and reproducibility of optical coherence tomography (OCT) Spectralis retinal thickness measurements in diabetic patients with clinically significant macular edema (CSME). METHODS: Twelve eyes of 12 volunteers (without macular pathology - control group) and 21 eyes of 21 diabetic patients with CSME were included in the study. Reproducibility, repeatability, intraclass correlation coefficients (ICCs) and intrasession correlation coefficients were tested with 20 × 15 degree raster scans consisting of 19 high-resolution line scans that were repeated three times by two experienced examiners. RESULTS: In the control group, examining all regions, coefficient of repeatability was less than 1.1%, while coefficient of reproducibility was less than 2.2%. In diabetic patients, examining all regions, coefficient of repeatability was less than 2.6%, while coefficient of reproducibility was less than 2.4%. ICCs were, respectively, greater than or equal to 0.98 in the control group and 0.99 in diabetic patients. Intrasession coefficients of variation were less than 0.4% in the control group and less than 0.5% in diabetic patients. CONCLUSION: Retinal thickness measurements are repeatable and reproducible with OCT Spectralis in both the control group and diabetic patients. The results indicate that a change in central subfield thickness exceeding 12 µm and 3% in the diabetic patients is likely to be real.
Assuntos
Retinopatia Diabética/patologia , Edema Macular/patologia , Retina/patologia , Tomografia de Coerência Óptica/métodos , Tomografia de Coerência Óptica/normas , Adulto , Feminino , Humanos , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes , Software , Acuidade VisualRESUMO
PURPOSE: To report 3 cases of simultaneous Descemet stripping automated endothelial keratoplasty (DSAEK) and aphakic iris-fixated intraocular lens (IOL) implantation in patients with aphakia and bullous keratopathy. METHODS: We retrospectively documented the clinical characteristics of patients before and after simultaneous DSAEK and aphakic iris-fixated IOL implantation undergoing operation between November 2008 and September 2009. RESULTS: None of the cases showed any intraoperative complications. During the postoperative period, the corneal lenticule was clear and well-attached, and the iris-fixated IOL was well-positioned. CONCLUSIONS: Simultaneous DSAEK and aphakic iris-fixated IOL implantation can be used successfully and simultaneously in patients with aphakia and bullous keratopathy.
Assuntos
Afacia Pós-Catarata/reabilitação , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior , Iris/cirurgia , Implante de Lente Intraocular , Idoso , Idoso de 80 Anos ou mais , Câmara Anterior/cirurgia , Extração de Catarata , Contagem de Células , Endotélio Corneano/patologia , Humanos , Masculino , Estudos Retrospectivos , Acuidade Visual/fisiologiaRESUMO
Syntheses of the [Lys(7)]- and [Hyp(6),Lys(7)]-dermorphin analogues in which either Tyr(5) or Hyp(6) are O-glucosylated are described. For comparison, the carbohydrate-free peptides have also been prepared. Structural investigations by FT-IR and CD measurements were carried out on the synthetic analogues and some preliminary pharmacological experiments were also performed. The biological potency of the glucosylated analogues was compared with that of the micro-opioid receptor agonist dermorphin in GPI preparations. Glucosylation of either Tyr(5) or Hyp(6) reduces the potency of both [Lys(7)]-dermorphin and [Hyp(6),Lys(7)]-dermorphin. The effect induced by the Tyr(5) glucosylation is quite strong and the potency of both peptides is reduced by about 150 times. A similar but less dramatic effect is induced by the glucosylation of the Hyp(6) residue, and the potency of the parent peptide is reduced by about 15 times. The presence of acetyl groups on the sugar hydroxyl functions further reduces the agonistic potency of the glucosylated analogues. The analgesic potency of [Hyp(6),Lys(7)]-, [Hyp(betaGlc)(6),Lys(7)]- and [Tyr(betaGlc)(5),Lys(7)]-dermorphin were also tested in vivo by the tail-flick test. The glucosylated hydroxyproline-containing analogue is 8-10 times less active than the parent peptide, but its analgesic effect lasts significantly longer.
Assuntos
Glicopeptídeos/química , Peptídeos Opioides/química , Sequência de Aminoácidos , Analgésicos/farmacologia , Animais , Dicroísmo Circular , Glicopeptídeos/farmacologia , Glicosilação , Cobaias , Masculino , Plexo Mientérico/efeitos dos fármacos , Peptídeos Opioides/síntese química , Peptídeos Opioides/farmacologia , Medição da Dor , Ratos , Receptores Opioides mu/agonistas , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Two simple lipid A analogues methyl 2,3-di-O-tetradecanoyl-alpha-D-glucopyranoside (GL1) and methyl 2,3-di-O-tetradecanoyl-alpha-D-glucopyranoside 4-O-phosphate (GL2) were synthesized and used for preparing mixed phosphocholine vesicles as models of the outer membrane of gram-negative bacteria. The interaction of these model membranes with magainin 2, a representative of the alpha-helical membrane active peptides, and apidaecin Ib and drosocin, two insect Pro-rich peptides which do not act at the level of the cellular membrane, were studied by CD and dye-releasing experiments. The CD spectra of apidaecin Ib and drosocin in the presence of GL1- or GL2-containing vesicles were consistent with largely unordered structures, whereas, according to the CD spectra, magainin 2 adopted an amphipathic alpha-helical conformation, particularly in the presence of negatively charged bilayers. The ability of the peptides to fold into amphipathic conformations was strictly correlated to their ability to bind and to permeabilize phospholipid as well as glycolipid membranes. Apidaecin Ib and drosocin, which are unable to adopt an amphipathic structure, showed negligible dye-leakage activity even in the presence of GL2-containing vesicles. It is reasonable to suppose that, as for the killing mechanism, the two classes of antimicrobial peptides follow different patterns to cross the bacterial outer membrane.
Assuntos
Antibacterianos/farmacologia , Membrana Celular/química , Glicolipídeos/química , Bactérias Gram-Negativas/química , Modelos Biológicos , Peptídeos/farmacologia , Antibacterianos/química , Permeabilidade da Membrana Celular , Modelos Moleculares , Peptídeos/químicaRESUMO
The conformational properties of the homo oligomers of increasing chain length Boc-(Asn)(n)-NHMe (n = 2, 4, 5), (GlcNAc-beta-Asn)(n)-NHMe (n = 2, 4, 5, 8) and Boc-[GlcNAc(Ac)(3)-beta-Asn](n)-NHMe (n = 2, 4, 5) were studied by using NOE experiments and molecular dynamic calculations (MD). Sequential NOEs and medium range NOEs, including (i,i+2) interactions, were detected by ROESY experiments and quantified. The calculated inter-proton distances are longer than those characteristic of beta-turn secondary structures. Owing to the large conformational motions expected for linear peptides, MD simulations were performed without NMR constraints, with explicit water and by applying different treatments of the electrostatic interactions. In agreement with the NOE results, the simulations showed, for all peptides, the presence of both folded and unfolded structures. The existence of significant populations of beta-turn structures can be excluded for all the examined compounds, but two families of structures were more often recognized. The first one with sinusoidal or S-shaped forms, and another family of large turns together with some more extended conformations. Only the glycosylated pentapeptide shows in vacuo a large amount of structures with helical shaped form. The results achieved in water and in DMSO are compared and discussed, together with the effect of the glycosylation.
Assuntos
Asparagina/química , Oligopeptídeos/química , Dipeptídeos/química , Espectroscopia de Ressonância de Spin Eletrônica , Glicosilação , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , TemperaturaRESUMO
The IgG-derived immunomodulating peptide tuftsin, Thr-Lys-Pro-Arg, is recognized by specific receptors on phagocytic cells, notably macrophages, and is capable of targeting proteins and peptides to these sites. Aiming to target 3'-azido-3'-deoxythymidine (AZT) to HIV-infected macrophages, a conjugate of AZT with tuftsin was synthesized. The AZT-tuftsin chimera possesses the characteristic capacities of its two components. Thus, like AZT, it inhibits reverse transcriptase activity and HIV-antigen expression, and similarly to tuftsin, it stimulates IL-1 release from mouse macrophages and augments the immunogenic function of the cells. Importantly, the conjugate is not cytotoxic to T-cells. The results suggest that the AZT-tuftsin conjugate might have potential use in AIDS therapy.
Assuntos
Fármacos Anti-HIV/farmacologia , Transcriptase Reversa do HIV/antagonistas & inibidores , HIV-1/efeitos dos fármacos , Macrófagos/virologia , Inibidores da Transcriptase Reversa/farmacologia , Tuftsina/análogos & derivados , Tuftsina/síntese química , Zidovudina/análogos & derivados , Zidovudina/síntese química , Animais , Fármacos Anti-HIV/toxicidade , Apresentação de Antígeno , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Portadores de Fármacos , Desenho de Fármacos , Feminino , Transcriptase Reversa do HIV/metabolismo , HIV-1/fisiologia , Humanos , Interleucina-1/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Inibidores da Transcriptase Reversa/toxicidade , Tuftsina/farmacologia , Tuftsina/toxicidade , Replicação Viral/efeitos dos fármacos , Zidovudina/farmacologia , Zidovudina/toxicidadeRESUMO
Stepwise solution syntheses of the homo-oligomers Boc-(Asn)n-NHCH3 (n = 1-5; I1-5), Boc-[[GlcNAc(Ac)3beta]Asn]n-NHCH3 (n = 1-8; II1-8), and Boc-[(GlcNAcbeta)Asn]n-NHCH3 (n = 1-8; III1-8) are described. Members of the series III were obtained by deacetylation of the corresponding members of the series II. The conformational preferences of the N-protected homo-peptides of the three series were investigated by spectroscopic techniques. 1H-NMR measurements were carried out in various solvents; the CD spectra were recorded in water, aqueous SDS and TFE. The poor solubility of the oligomers of the three series prevented FT-IR measurements in solution. NMR and IR measurements indicate the existence of unordered structures containing some gamma-turns in the carbohydrate-free oligomers and the presence of beta-turns in the glycosylated oligopeptides, whether acetylated or not. The CD spectra do not indicate the presence of organized structures. The sugar moieties apparently do not have a structure-inducing effect on the asparagine homo-oligomer main chain.
Assuntos
Asparagina/química , Glicosilação , Oligopeptídeos/química , Dicroísmo Circular , Espectroscopia de Ressonância Magnética , Biossíntese Peptídica , Politetrafluoretileno , Dodecilsulfato de Sódio/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The [D-Ala2]deltorphin 1 sequence in which the aspartic acid residue is replaced by the N gamma-OCH3-alpha, gamma-diamino (S) butanoyl residue was synthesized using the Fmoc-chemistry-based solid phase procedure. The resulting deltorphin analogue was chemoselectively glucosylated by reaction with unprotected D-glucose (Glc). The Asn4-, (2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-galactopyranosyl)-Asn4- and the (2-acetamido-2-deoxy-D-galactopyranosyl)-Asn4-deltorphin I were also prepared for comparison. The affinity of the new compounds for the delta-opioid receptor was expressed by the inhibition constant (Ki) of the binding of the delta-receptor selective ligand [3H]naltrindole (NTI) to rat brain membrane preparations. The in vitro biological activity of the synthetic peptides was compared with that of the mu-opioid receptor agonist dermorphin in guinea pig ileum (GPI) preparations and with that of the delta-opioid receptor agonist deltorphin I in mouse vas deferens (MVD) preparations. The substitution of Asp4 with Asn failed to affect drastically the Ki and IC50 values for delta-sites, suggesting that an electrostatic interaction does not play an essential role in the binding to delta-opioid sites. The steric hindrance of the side chain of the residue in position 4 affects binding to delta-sites. The increase of the Ki value is smaller when the sugar-peptide linkage involves the gamma-nitrogen of the Dab residue in comparison with the Asn amide side chain.