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1.
J Colloid Interface Sci ; 553: 289-297, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31212228

RESUMO

The fascinating properties of graphene can be augmented with other nanomaterials to generate hybrids to design innovative applications. Contrary to the conventional methodologies, we showed a novel yet simple, in-situ, biological approach which allowed for the effective growth of gold nanostructures on graphene surfaces (3D Au NS@GO). The morphology of the obtained hybrid consisted of sheets of graphene, anchoring uniform dispersion of ultra-small gold nanostructures of about 2-8 nm diameter. Surface plasmon resonance at 380 nm confirmed the nano-regimen of the hybrid. Fourier transform infrared spectroscopy indicated the utilization of amine spacers to host gold ions leading to nucleation and growth. The exceptional positive surface potential of 55 mV suggest that the hybrid as an ideal support for electrocatalysis. Ultimately, the hybrid was found to be an efficient receptor material for electrochemical performance towards the binding of uric acid which is an important biomolecule of human metabolism. The designed material enabled the detection of uric acid concentrations as low as 30 nM. This synthesis strategy is highly suitable to design new hybrid materials with interesting morphology and outstanding properties for the identification of clinically relevant biomolecules.

2.
Biosens Bioelectron ; 136: 118-127, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054519

RESUMO

A simple, single-masked gold interdigitated triple-microelectrodes biosensor is presented by taking the advantage of an effective self-assembled monolayer (SAM) using an amino-silanization technique for the early detection of a prostate cancer's biomarker, the prostate-specific antigen (PSA). Unlike most interdigitated electrode biosensors, biorecognition happens in between the interdigitated electrodes, which enhances the sensitivity and limit of detection of the sensor. Using the Faradaic mode electrochemical impedance spectroscopy (EIS) technique to quantify the PSA antigen, the developed sensing platform demonstrates a logarithmic detection of PSA ranging from 0.5 ng/ml to 5000 ng/ml, an estimated LOD down to 0.51 ng/ml in the serum, and a good sensor's reproducibility. The sensor's detection range covers the clinical threshold value at 4 ng/ml and the crucial diagnosis 'grey zone' of 4-10 ng/ml of PSA in serum for an accurate cancer diagnosis. The selectivity test revealed an excellent discrimination of other competing proteins, with a recorded detection signals at 5 ng/ml PSA as high as 7-fold increase versus the human serum albumin (HSA) and 8-fold increase versus the human glandular kallikrein 2 (hK2). The stability test showed an acceptable stability of the aptasensor recorded at six (6) days before the detection signal started degrading below 10% of the peak detection value. The developed sensing scheme is proven to exhibit a great potential as a portable prostate cancer biosensor, also as a universal platform for bio-molecular sensing with the versatility to implement nanoparticles and other surface chemistry for various applications.


Assuntos
Técnicas Biossensoriais/métodos , Ouro , Microeletrodos , Antígeno Prostático Específico/sangue , Ouro/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica
3.
J Morphol ; 280(3): 436-445, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30747455

RESUMO

The echimyid rodents of the genus Thrichomys vary considerably in their behavior and feeding ecology, reflecting their occurrence in environments as different as the Caatinga, Cerrado, Pantanal, and Chaco biomes. While the genus was originally classified as monospecific, a number of Thrichomys species have been recognized in recent decades, based on morphometric, cytogenetic, and molecular analyses. While Thrichomys is well studied, the variation found in its cranial morphology is poorly understood, given the taxonomic and ecological complexities of the genus. Using a geometric morphometric approach, we characterized the differences found in the cranial morphology of four Thrichomys taxonomic units, including three established species, Thrichomys apereoides, Thrichomys fosteri, and Thrichomys laurentius, and one operational taxonomic unit (OTU), Thrichomys aff. laurentius. No significant differences were found among these units in cranium size, but significant variation was found in skull shape. The Procrustes distances provided a quantification of the differences in the shape of the skull, with the largest distances being found between T. aff. laurentius and T. fosteri in the dorsal view, and between T. aff. laurentius and T. apereoides in the ventral view. A Discriminant Function Analysis (DFA) with cross-validation determined that the pairings with the highest correct classification were T. aff. laurentius vs. T. apereoides and T. aff. laurentius vs. T. fosteri, in both views. The principal variation in skull shape was found in the posterior region and the zygomatic arch, which may be related to differences in diet.

4.
Sensors (Basel) ; 19(1)2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30609788

RESUMO

Although prostate cancer is one of the most common cancers in the male population, its basic biological function at a cellular level remains to be fully understood. This lack of in depth understanding of its physiology significantly hinders the development of new, targeted and more effective treatment strategies. Whilst electrophysiological studies can provide in depth analysis, the possibility of recording electrical activity in large populations of non-neuronal cells remains a significant challenge, even harder to address in the picoAmpere-range, which is typical of cellular level electrical activities. In this paper, we present the measurement and characterization of electrical activity of populations of prostate cancer cells PC-3, demonstrating for the first time a meaningful electrical pattern. The low noise system used comprises a multi-electrode array (MEA) with circular gold electrodes on silicon oxide substrates. The extracellular capacitive currents present two standard patterns: an asynchronous sporadic pattern and a synchronous quasi-periodic biphasic spike pattern. An amplitude of ±150 pA, a width between 50⁻300 ms and an inter-spike interval around 0.5 Hz characterize the quasi-periodic spikes. Our experiments using treatment of cells with Gd³âº, known as an inhibitor for the Ca²âº exchanges, suggest that the quasi-periodic signals originate from Ca²âº channels. After adding the Gd³âº to a population of living PC-3 cells, their electrical activity considerably decreased; once the culture was washed, thus eliminating the Gd³âº containing medium and addition of fresh cellular growth medium, the PC-3 cells recovered their normal electrical activity. Cellular viability plots have been carried out, demonstrating that the PC-3 cells remain viable after the use of Gd³âº, on the timescale of this experiment. Hence, this experimental work suggests that Ca²âº is significantly affecting the electrophysiological communication pattern among PC-3 cell populations. Our measuring platform opens up new avenues for real time and highly sensitive investigations of prostate cancer signalling pathways.


Assuntos
Fenômenos Eletrofisiológicos , Espaço Extracelular/fisiologia , Neoplasias da Próstata/ultraestrutura , Bloqueadores dos Canais de Cálcio/farmacologia , Eletricidade , Eletrodos , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Gadolínio/farmacologia , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Modelos Biológicos , Células PC-3 , Neoplasias da Próstata/metabolismo
5.
Biosens Bioelectron ; 123: 30-35, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30308419

RESUMO

There has been a continuous strive to develop portable, stable, sensitive and low cost detection system for malaria to meet the demand of effective screening actions in developing countries where the disease is most endemic. Herein, we report an aptamer-based field effect transistor (aptaFET) biosensor, developed by using an extended gate field effect transistor with inter-digitated gold microelectrodes (IDµE) for the detection of the malaria biomarker Plasmodium falciparum glutamate dehydrogenase (PfGDH) in serum samples. A 90 mer long ssDNA aptamer (NG3) selective to PfGDH was used in the aptaFET to capture the target protein. The intrinsic surface net charge of the captured protein led to change in gate potential of the aptaFET device, which could be correlated to the concentration of the protein. This biosensor exhibited a sensitive response in broad dynamic range of 100 fM -10 nM with limits of detection of 16.7 pM and 48.6 pM in spiked buffer and serum samples, respectively. The high selectivity of the biosensor for PfGDH was verified by testing relevant analogous human and parasitic proteins on the device. Overall, the results validated the application potential of the developed aptaFET for diagnosis of both symptomatic and asymptomatic malaria.


Assuntos
Técnicas Biossensoriais , Glutamato Desidrogenase/isolamento & purificação , Malária/sangue , Plasmodium falciparum/enzimologia , Aptâmeros de Nucleotídeos/química , DNA de Cadeia Simples/química , Glutamato Desidrogenase/sangue , Glutamato Desidrogenase/química , Ouro/química , Humanos , Limite de Detecção , Malária/parasitologia , Plasmodium falciparum/patogenicidade
6.
Biosens Bioelectron ; 123: 244-250, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30243847

RESUMO

We report the development of a Lab-on-PCB DNA diagnostic platform, exploiting peptide nucleic acid (PNA) sequences as probes. The study demonstrates the optimization and characterization of two commercial PCB manufacturing gold electroplating processes for biosensing applications. Using an optimized ratio of PNA with a spacer molecule (MCH), the lowest limit of detection (LoD) to date for PCB-based DNA biosensors of 57 fM is reported. The study also showcases a fully integrated Lab-on-PCB microsystem designed for rapid detection, which employs PCB-integrated sample delivery, achieving DNA quantification in the 0.1-100 pM range for 5 µL samples analyzed within 5 min under continuous flow. The demonstrated biosensor proves the capability of PCB-based DNA biosensors for high sensitivity and paves the way for their integration in Lab-on-PCB DNA diagnostic microsystems.


Assuntos
Técnicas Biossensoriais , DNA/isolamento & purificação , Dispositivos Lab-On-A-Chip , Ácidos Nucleicos Peptídicos/química , DNA/química , Ouro/química , Limite de Detecção
7.
Biosens Bioelectron ; 130: 352-359, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30269960

RESUMO

In the field of label-free biosensing, various transducer materials and strategies are under investigation to overcome the Debye-screening limitation of charged biomolecules. We demonstrate an in-line, impedimetric aptasensor with reduced graphene-oxide (rGO) thin films as transducers to detect prostate specific antigens (PSA) in a physiological buffer solution. Unlike classical electrochemical impedance spectroscopy (EIS), this direct, label-free and fully-electronic biosensor approach does not need any redox markers. As specific capture molecules, short anti-PSA aptamers ensured a close binding of the target molecules to the transducer surfaces. Results showed a limit of detection smaller than 33 pM of PSA and a wide detection range from 0.033 to 330 nM fully covering the clinically relevant range of PSA (0.115-0.290 nM). This promising performance can be attributed to the bipolar electronic transport characteristics of the ultra-thin rGO layers similar to pristine graphene. The attachment of target biomolecules to the films changes the resistance of the rGO thin films. Such an in-line EIS configuration with rGO thin films opens promising prospects for biosensing beyond the Debye-screening limitation, which is a major challenge for conventional semiconductor field-effect devices towards clinical applications.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Grafite/química , Antígeno Prostático Específico/isolamento & purificação , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Humanos , Limite de Detecção , Antígeno Prostático Específico/química
8.
Biosens Bioelectron ; 123: 141-151, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30078622

RESUMO

Tuberculosis (TB) remains one of the leading causes of mortality worldwide. There is a great need for the development of diagnostic tests, which are reliable, sensitive, stable, and low cost to enable early diagnosis of TB in communities with scarce resources. This study reports the optimization and evaluation of a synthetic receptor, an aptamer, for the detection of the secreted protein MPT64, which is a highly immunogenic polypeptide of Mycobacterium tuberculosis, a causative agent of TB. The study investigates combinatorial effects of an aptamer linker and a co-adsorbent onto a gold electrode for optimal binding efficiency and reduced non-specific interactions for label-free detection of MPT64 using electrochemical impedance spectroscopy. Two types of co-adsorbents and two types of aptamer linkers were studied and high specificity and sensitivity to MPT64 was observed for a surface prepared with a thiol PEGylated aptamer HS-(CH2)6-OP(O)2O-(CH2CH2O)6-TTTTT-aptamer and 6-mercaptohexanol in a ratio of 1:100. The developed aptamer-based sensor was successfully used with spiked human serum sample with a limit of detection of 81 pM This work demonstrates the use of the MPT64 aptamer as a lower cost, more sustainable and stable alternative of antibodies for the development of point-of-care TB biosensors decreasing the detection time from several days or hours to thirty minutes.


Assuntos
Antígenos de Bactérias/isolamento & purificação , Proteínas de Bactérias/isolamento & purificação , Técnicas Biossensoriais , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/sangue , Antígenos de Bactérias/sangue , Proteínas de Bactérias/sangue , Testes Diagnósticos de Rotina/métodos , Espectroscopia Dielétrica/métodos , Ouro/química , Humanos , Mycobacterium tuberculosis/patogenicidade , Técnica de Seleção de Aptâmeros/métodos , Tuberculose/microbiologia
9.
An Acad Bras Cienc ; 90(3): 3007-3015, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304231

RESUMO

Plague is a zoonosis caused by Yersinia pestis, whose cycle is based on a reservoir system composed of mammals and their fleas. Its transmission cycle presents long enzootic periods with undetected cases, sometimes misleading that the cycle is extinct. While surveillance activities in Brazil are being carried out only in some focal areas, the serologic results confirm the persistence of Y. pestis in all monitored areas. We studied the small mammal assembly and Y. pestis presencein the Borborema Plateau Focus within the state of Paraíba, which staged the last Brazilian plague outbreak (1986-1987), through aninventory and Y. pestis detection survey of small mammals in peridomestic and sylvatic areas from two municipalities in the state of Paraíba.The field sampling captured 45 specimens (27 marsupials, 18 rodents), of 10 species. Only two species (one marsupial, one rodent) were captured in both peridomestic and sylvatic ecotopes. The sylvatic ecotope had higher richness and abundance. No evidence of circulation of the pathogen was detected, however, this result does not discard the necessity of continuous epidemiological surveillance due to the risk of rekindling the foci after long dormant periods, especially given the current epidemiological transition occurring on a Global scale.

10.
BMC Vet Res ; 14(1): 279, 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30200947

RESUMO

BACKGROUND: The role of bats as reservoirs of zoonotic agents, especially pathogenic bacteria such as Bartonella and Coxiella, has been discussed around the world. Recent studies have identified bats as potential hosts of species from the proteobacteria phylum. In Brazil, however, the role of bats in the natural cycle of these agents is poorly investigated and generally neglected. In order to analyze the participation of bats in the epidemiology of diseases caused by Bartonella, Coxiella, Rickettsia, Anaplasma and Ehrlichia, we conducted a descriptive epidemiological study in three biogeographic regions of the Brazilian Atlantic Forest. RESULTS: Tissues of 119 bats captured in preserved areas in the states of Rio de Janeiro, Bahia and Santa Catarina from 2014 to 2015 were submitted to molecular analysis using specific primers. Bartonella spp. was detected in 22 spleen samples (18.5%, 95% CI: 11.9-26.6), whose phylogenetic analysis revealed the generation of at least two independent clusters, suggesting that these may be new unique genotypes of Bartonella species. In addition, four samples (3.4%, 95% CI: 0.9-8.3) were positive for the htpAB gene of C. burnetii [spleen (2), liver (1) and heart (1)]. Rickettsia spp., Anaplasma and Ehrlichia were not identified. This is the first study reporting C. burnetii and Bartonella spp. infections in bats from the Atlantic Forest biome. CONCLUSIONS: These findings shed light on potential host range for these bacteria, which are characterized as important zoonotic pathogens.


Assuntos
Bartonella/isolamento & purificação , Quirópteros/microbiologia , Coxiella/isolamento & purificação , Animais , Bartonella/genética , Infecções por Bartonella/epidemiologia , Brasil/epidemiologia , Coxiella/genética , DNA Bacteriano , Feminino , Florestas , Bactérias Gram-Negativas , Masculino , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Baço/microbiologia , Zoonoses/epidemiologia
11.
Nanoscale ; 10(28): 13320-13328, 2018 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-29974109

RESUMO

Multimodal sensing methods have a great promise in biosensing applications as they can measure independently several properties that characterise the biomolecular interaction to be detected as well as providing inherent on-chip validation of the sensing signals. This work describes the mechanisms of a concept of insulator-semiconductor field-effect devices coupled with nanoplasmonic sensing as a promising technology, which can be used for a wide range of analytical sensing applications. The developed method involves coupling of the localized surface plasmons (LSPs) within gold nanoparticles (AuNPs) and excitons within pH sensitive silicon nitride (Si3N4) nanofilms for screening inhibitors of kinase, which constitute an important class of chemotherapy drugs. In parallel to this optical sensing, the pH sensitivity of silicon nitride is used to detect the release of protons associated with kinase activity. By changing the insulator and AuNPs characteristics, this work demonstrates the nanoplasmonic-exciton effects taking place, enabling the developed platform to be used for screening kinase inhibitors and as a dual mode electro-optical biosensor for routine bio/chemical sensing applications.


Assuntos
Técnicas Biossensoriais , Descoberta de Drogas , Nanopartículas Metálicas , Inibidores de Proteínas Quinases/farmacologia , Semicondutores , Ouro , Fosforilação , Prótons , Compostos de Silício
12.
Biosens Bioelectron ; 117: 620-627, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30005382

RESUMO

A novel fluidic-based electrochemical ELISA platform is descried for estimation of the bladder cancer protein markers nuclear mitotic apparatus protein 1 (NUMA1) and complement factor H-related 1 (CFHR1). The platform uses an off-site chamber for a sandwich immunoassay and performs the electrochemistry on-chip in a separate chamber. The off-site matrices were connected to the sensor chip in a manner that the sensors were exposed only to the final electroactive product for signal detection, thus avoiding interference from other molecules present in the sample. Two off-site matrices using 3D polymethyl methacrylate (PMMA) sheets and 2D polycarbonate (PC) membranes modified with the desired antibodies were investigated. Antibodies for NUMA1 and CFHR1 were utilized for the immunoassay and hair comb structured gold electrodes were used for sensing. Results in 10% synthetic urine reveal that the system can detect NUMA1 and CFHR1 in the 1-100 ng/ml range with high sensitivities of 260 nA/(ng/ml) and 310 nA/(ng/ml), for NUMA1 and CFHR1, respectively; negligible interference from the diluted urine and other molecules has been observed. A fully automated fluidic prototype has also been developed to demonstrate that automation of the process and multiplexing of detection can be achieved in a small footprint benchtop device. The use of off-site matrix-based platforms paves the way towards a new generation of electrochemical immunosensors for biomarker estimation with negligible non-specific interactions and false signals in complex samples.


Assuntos
Biomarcadores/urina , Técnicas Biossensoriais/métodos , Eletroquímica , Ensaio de Imunoadsorção Enzimática , Urinálise/métodos , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/urina , Técnicas Biossensoriais/instrumentação , Humanos , Limite de Detecção , Urinálise/instrumentação
13.
Sensors (Basel) ; 18(7)2018 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-29932161

RESUMO

Electrochemical enzyme-linked immunosorbent assay (ELISA)-based immunoassays for cancer biomarker detection have recently attracted much interest owing to their higher sensitivity, amplification of signal, ease of handling, potential for automation and combination with miniaturized analytical systems, low cost and comparative simplicity for mass production. Their developments have considerably improved the sensitivity required for detection of low concentrations of cancer biomarkers present in bodily fluids in the early stages of the disease. Recently, various attempts have been made in their development and several methods and processes have been described for their development, amplification strategies and testing. The present review mainly focuses on the development of ELISA-based electrochemical immunosensors that may be utilized for cancer diagnosis, prognosis and therapy monitoring. Various fabrication methods and signal enhancement strategies utilized during the last few years for the development of ELISA-based electrochemical immunosensors are described.


Assuntos
Biomarcadores Tumorais/análise , Técnicas Eletroquímicas , Ensaio de Imunoadsorção Enzimática/métodos , Neoplasias/diagnóstico , Neoplasias/metabolismo , Biomarcadores Tumorais/imunologia , Humanos , Oxirredução
14.
Acta Trop ; 185: 267-272, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29883575

RESUMO

Bats are considered important reservoirs of pathogens of veterinary and medical relevance worldwide. However, despite the increasing attention paid towards the central role of bats in the spreading of some zoonotic infections, studies on their own parasites remain patchy especially in Neotropical regions. Understanding the relationships occurring between bats and their pathogens is a crucial step to determine the implications undermining the ecology and biology of these animals. The present study aims to assess the endoparasitic fauna of Neotropical bats from Northeastern Brazil, with a particular focus on helminths and protozoa. From October 2016 to March 2017, 54 fresh faecal samples were collected in stable shelters inhabited by three different bat species (i.e., Molossus molossus, Myotis lavali and Noctilio albiventris). Samples were analysed using four different techniques (i.e., Centrifugal Sedimentation, Flotation Technique, Spontaneous Sedimentation Technique and FLOTAC®). A total of 96.29% (52/54) samples were positive for at least one gastrointestinal parasite and 11 different families were identified. In particular, 63.6% (7/11) of the families were of helminths and 36.4% (4/11) of protozoa. Helminths were classified into two different classes (Nematoda and Cestoda) and seven families, whereas the four protozoa classes detected (i.e., Coccidia, Gregarinomorphe, Lobosea and Zoomastigophora) into four families. Eggs of Ancylostomatidae and Hymenolepididae were the most abundan. The findings of this present study demonstrate that Neotropical bats from Northeastern Brazil are parasitized by a wide number of parasites, and some of them may have important implications for Public Health.


Assuntos
Quirópteros/parasitologia , Reservatórios de Doenças/virologia , Helmintos/isolamento & purificação , Parasitos/isolamento & purificação , Animais , Brasil , Fezes/parasitologia , Zoonoses/transmissão , Zoonoses/virologia
15.
Biosens Bioelectron ; 117: 246-252, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-29909195

RESUMO

A capacitive aptasensor for detecting the malaria biomarker, Plasmodium falciparum glutamate dehydrogenase (PfGDH), directly in human serum samples developed. A thiolated ssDNA aptamer (NG3) that binds specifically to PfGDH antigen with high affinity (Kd= 79 nM) was used to develop the aptasensor. The aptasensor produced capacitance response at an optimized frequency of 2 Hz in a non-Faradaic electrochemical impedance based signal transduction platform. The aptasensor exhibited a wide dynamic range of 100 fM-100 nM with a limits of detection of 0.77 pM in serum samples. The interference from other predominant malarial biomarkers, namely, Plasmodium falciparum -lactate dehydrogenase and -histidine rich protein-II on the aptasensor was negligible. This PfGDH aptasensor with highly sensitive and label free detection capability has great application potential for diagnosis of asymptotic malaria and monitoring the regression of malaria during treatment regime with antimalarial drugs.


Assuntos
Antígenos de Protozoários/metabolismo , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas , Glutamato Desidrogenase/sangue , Malária/diagnóstico , Antígenos de Protozoários/sangue , Aptâmeros de Nucleotídeos/metabolismo , Glutamato Desidrogenase/metabolismo , Humanos , Limite de Detecção , Malária/sangue , Plasmodium falciparum/enzimologia
16.
Sci Rep ; 8(1): 5484, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29615779

RESUMO

Diatoms are photosynthetic microalgae, a group with a major environmental role on the planet due to the biogeochemical cycling of silica and global fixation of carbon. However, they can evolve into harmful blooms through a resourceful communication mechanism, not yet fully understood. Here, we demonstrate that a population of diatoms under darkness show quasi-periodic electrical oscillations, or intercellular waves. The origin is paracrine signaling, which is a feedback, or survival, mechanism that counteracts changes in the physicochemical environment. The intracellular messenger is related to Ca2+ ions since spatiotemporal changes in their concentration match the characteristics of the intercellular waves. Our conclusion is supported by using a Ca2+ channel inhibitor. The transport of Ca2+ ions through the membrane to the extracellular medium is blocked and the intercellular waves disappear. The translation of microalgae cooperative signaling paves the way for early detection and prevention of harmful blooms and an extensive range of stress-induced alterations in the aquatic ecosystem.


Assuntos
Escuridão , Diatomáceas/fisiologia , Fenômenos Eletrofisiológicos/fisiologia , Estresse Fisiológico , Transporte Biológico , Cálcio/metabolismo , Cloroplastos/metabolismo , Citosol/metabolismo , Diatomáceas/citologia , Diatomáceas/metabolismo , Espaço Extracelular/metabolismo , Comunicação Parácrina
17.
PLoS One ; 13(4): e0195084, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29624590

RESUMO

Dasypus is the most speciose genus of the order Cingulata, including approximately 40% of known living armadillos. Nine species are currently recognized, although comprehensive analyses of the entire genus have never been done. Our aim is to revise the taxonomy of the long-nosed armadillos and properly define the taxa. We examined 2126 specimens of Dasypus preserved in 39 different museum collections, including 17 type specimens. Three complementary methods were applied to explore morphological datasets both qualitatively and quantitatively. Qualitative morphological variation in discrete characters was assessed by direct observations of specimens. Linear morphometric variation was based on external data and cranial measurements of 887 adult skulls. The shape and size of the skull was abstracted through two-dimensional geometric morphometric analyses of dorsal, lateral and ventral views of respectively 421, 211, and 220 adult specimens. Our results converge on the recognition of eight living species (D. beniensis, D. kappleri, D. mazzai, D. novemcinctus, D. pastasae, D. pilosus, D. sabanicola, and D. septemcinctus), and three subspecies of D. septemcinctus (D. s. septemcinctus, D. s. hybridus, and a new subspecies from Cordoba described here). Information on type material, diagnosis, distribution, and taxonomic comments for each taxon are provided. We designate a lectotype for D. novemcinctus; and a neotype for Loricatus hybridus (= D. septemcinctus hybridus).


Assuntos
Tatus/anatomia & histologia , Tatus/classificação , Distribuição Animal , Animais , Geografia , Característica Quantitativa Herdável
18.
Genet Mol Biol ; 41(1 suppl 1): 263-272, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29668015

RESUMO

We tested the association between chromosomal polymorphism and skull shape and size variation in two groups of the subterranean rodent Ctenomys. The hypothesis is based on the premise that chromosomal rearrangements in small populations, as it occurs in Ctenomys, produce reproductive isolation and allow the independent diversification of populations. The mendocinus group has species with low chromosomal diploid number variation (2n=46-48), while species from the torquatus group have a higher karyotype variation (2n=42-70). We analyzed the shape and size variation of skull and mandible by a geometric morphometric approach, with univariate and multivariate statistical analysis in 12 species from mendocinus and torquatus groups of the genus Ctenomys. We used 763 adult skulls in dorsal, ventral, and lateral views, and 515 mandibles in lateral view and 93 landmarks in four views. Although we expected more phenotypic variation in the torquatus than the mendocinus group, our results rejected the hypothesis of an association between chromosomal polymorphism and skull shape and size variation. Moreover, the torquatus group did not show more variation than mendocinus. Habitat heterogeneity associated to biomechanical constraints and other factors like geography, phylogeny, and demography, may affect skull morphological evolution in Ctenomys.

19.
Biosens Bioelectron ; 108: 1-8, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29482002

RESUMO

A novel Affimer-functionalised interdigitated electrode-based capacitive biosensor platform was developed for detection and estimation of Her4, a protein tumour biomarker, in undiluted serum. An anti-Her4 Affimer with a C-terminal cysteine was used to create the bio-recognition layer via self-assembly on gold interdigitated electrodes for the sensor fabrication. Electrochemical impedance spectroscopy (EIS) in the absence of redox markers was used to evaluate the sensor performance by monitoring the changes in capacitance. The Affimer sensor in buffer and in undiluted serum demonstrated high sensitivity with a broad dynamic range from 1 pM to 100 nM and a limit of detection lower than 1 pM both in buffer and in serum. Furthermore, the Affimer sensor demonstrated excellent specificity with negligible interference from serum proteins, suggesting resilience to non-specific binding. The sensing ability of the present Affimer sensor in spiked undiluted serum suggests its potential for a new range of Affimer-based sensors. The fabricated Affimer sensor can thus be further adapted with other probes having affinities to other biomarkers for a new range of biosensors.


Assuntos
Biomarcadores Tumorais/análise , Técnicas Biossensoriais/métodos , Cisteína/análogos & derivados , Receptor ErbB-4/análise , Biomarcadores Tumorais/química , Tampões (Química) , Cisteína/química , Capacitância Elétrica , Técnicas Eletroquímicas , Eletrodos , Ouro/química , Humanos , Limite de Detecção , Receptor ErbB-4/química , Soro/química , Silicones/química
20.
Biosens Bioelectron ; 102: 106-112, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29127898

RESUMO

We report the development of a simple and powerful capacitive aptasensor for the detection and estimation of human epidermal growth factor receptor 2 (HER2), a biomarker for breast cancer, in undiluted serum. The study involves the incorporation of interdigitated gold electrodes, which were used to prepare the electrochemical platform. A thiol terminated DNA aptamer with affinity for HER2 was used to prepare the bio-recognition layer via self-assembly on interdigitated gold surfaces. Non-specific binding was prevented by blocking free spaces on surface via starting block phosphate buffer saline-tween20 blocker. The sensor was characterized using cyclic voltammetry, electrochemical impedance spectroscopy (EIS), atomic force microscopy and contact angle studies. Non-Faradic EIS measurements were utilized to investigate the sensor performance via monitoring of the changes in capacitance. The aptasensor exhibited logarithmically detection of HER2 from 1pM to 100nM in both buffer and undiluted serum with limits of detection lower than 1pM. The results pave the way to develop other aptamer-based biosensors for protein biomarkers detection in undiluted serum.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Neoplasias da Mama/sangue , Técnicas Eletroquímicas/métodos , Receptor ErbB-2/sangue , Compostos de Sulfidrila/química , Técnicas Biossensoriais/instrumentação , Capacitância Elétrica , Técnicas Eletroquímicas/instrumentação , Eletrodos , Desenho de Equipamento , Feminino , Ouro/química , Humanos , Limite de Detecção
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