RESUMO

The detection of magnetic fields by animals is known as magnetoreception. The ferromagnetic hypothesis explains magnetoreception assuming that magnetic nanoparticles are used as magnetic field transducers. Magnetite nanoparticles in the abdomen of Apis mellifera honeybees have been proposed in the literature as the magnetic field transducer. However, studies with ants and stingless bees have shown that the whole body of the insect contain magnetic material, and that the largest magnetization is in the antennae. The aim of the present study is to investigate the magnetization of all the body parts of honeybees as has been done with ants and stingless bees. To do that, the head without antennae, antennae, thorax, and abdomen obtained from Apis mellifera honeybees were analyzed using magnetometry and Ferromagnetic Resonance (FMR) techniques. The magnetometry and FMR measurements show the presence of magnetic material in all honeybee body parts. Our results present evidence of the presence of biomineralized magnetite nanoparticles in the honeybee abdomen and, for the first time, magnetite in the antennae. FMR measurements permit to identify the magnetite in the abdomen as biomineralized. As behavioral experiments reported in the literature have shown that the abdomen is involved in magnetoreception, new experimental approaches must be done to confirm or discard the involvement of the antennae in magnetoreception.

Assuntos

RESUMO

Esta pesquisa tem como objetivo analisar as relações entre questões de gênero e as práticas de lazer de professores e professoras de Educação Física (EF) das escolas públicas de Sete Lagoas, na pandemia. Utilizou-se como procedimentos metodológicos: questionário semiaberto via Google Forms e entrevista semiestruturada. Constatou-se que o gênero se configurou enquanto elemento de diferença de oportunidade e usufruto do tempo, espaço e experiências de lazer, em especial no caso das professoras que se identificaram como sexo feminino, mulheres cis e heterossexuais e dos professores que autodeclararam gays, sexo masculino e homens cis. No que se refere às práticas de lazer dessas pessoas, constatou-se a predominância de atividades relacionadas ao interesse virtual, como, por exemplo, o uso de redes sociais como Facebook, Instagram, WhatsApp e TikTok, bem como a utilização de plataformas digitais como Netflix e Prime Vídeo.

This research aims to analyze the relationships between gender issues and the leisure practices of Physical Education (PE) teachers at public schools in Sete Lagoas, during the pandemic. The following methodological procedures were used: semi-open questionnaire via Google Forms and semi-structured interview. It was found that gender was configured as an element of difference in opportunity and enjoyment of time, space and leisure experiences, especially in the case of teachers who identified themselves as female, cis and heterosexual women and teachers who declared themselves gay, sex masculine and cis men. Regarding leisure practices of these people, there was a predominance of activities related to virtual interest, such as, for example, the use of social networks such as Facebook, Instagram, WhatsApp and TikTok, as well as the use of digital platforms such as Netflix and Prime Video.

RESUMO

Magnetotactic bacteria are microorganisms that produce intracellular magnetic nanoparticles organized in chains, conferring a magnetic moment to the bacterial body that allows it to swim following the geomagnetic field lines. Magnetotactic bacteria usually display two swimming polarities in environmental samples: the South-seeking (SS) polarity and the North-seeking (NS) polarity, characterized by the bacteria swimming antiparallel or parallel to the magnetic field lines, respectively. It has been observed that in the presence of inhomogeneous magnetic fields, NS magnetotactic bacteria can change their swimming polarity to SS or vice versa. The present study analyzes populations of NS cocci obtained from SS cocci isolated in the presence of a magnet. The aim was to study differences in the swimming characteristics and magnetic moment among both populations of cocci. For that, trajectories were recorded and the velocity and angle among the velocity and the applied magnetic field were calculated. In addition, micrographs from both SS and NS cocci were obtained and their magnetosomes were measured to analyze their length, width, aspect ratio and magnetic moment, to finally obtain the magnetic moment for each coccus. The results showed the following properties of NS relative to SS cocci: higher velocities, narrow bacterial magnetic moment distribution, higher dispersion in the distribution of angles among the velocity and the applied magnetic field and lower magnetic field sensibility. Those differences cannot be explained by the simple change in magnetic polarity of the magnetosome chain and can be related to the existence of an active magnetoreceptive process in magnetotactic bacteria.

Assuntos

RESUMO

Mucorales are a group of non-septated filamentous fungi widely distributed in nature, frequently associated with human infections, and are intrinsically resistant to many antifungal drugs. For these reasons, there is an urgent need to improve the clinical management of mucormycosis. Miltefosine, which is a phospholipid analogue of alkylphosphocholine, has been considered a promising repurposing drug to be used to treat fungal infections. In the present study, miltefosine displayed antifungal activity against a variety of Mucorales species, and it was also active against biofilms formed by these fungi. Treatment with miltefosine revealed modifications of cell wall components, neutral lipids, mitochondrial membrane potential, cell morphology, and the induction of oxidative stress. Treated Mucorales cells also presented an increased susceptibility to SDS. Purified ergosterol and glucosylceramide added to the culture medium increased miltefosine MIC, suggesting its interaction with fungal lipids. These data contribute to elucidating the effect of a promising drug repurposed to act against some relevant fungal pathogens that significantly impact public health.

RESUMO

A Gram-stain-positive rod, psychrotolerant, aerobic and bioemulsifier-producing strain, denoted as Val9T, was isolated from soil sampled at Vale Ulman, King George Island, Antarctica. The strain grew at up to 30 °C (optimum, 15 °C), at pH 6-9 (optimum, pH 8) and with up to 5 % w/v NaCl (optimum, 3 %). The strain was motile and positive for catalase, oxidase and H2S. It did not hydrolyse starch, casein or gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Val9T belonged to the genus Psychrobacillus and was closely related to Psychrobacillus psychrotolerans DSM 11706T (99.9 % similarity), Psychrobacillus psychrodurans DSM 11713T (99.8 %) and Psychrobacillus glaciei PB01T (99.2 %). Digital DNA-DNA hybridization and average nucleotide identity values were lower than 37.3 and 85.5 %, respectively, with the closest phylogenetic neighbours. The DNA G+C content of strain Val9T calculated from the complete genome sequence was 36.6 mol%. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 1ω11c. Menaquinone-8 was the major respiratory quinone. The peptidoglycan type was A4ß l-Orn-d-glu. The novel strain contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol as predominant polar lipids. Based on 16S rRNA phylogenetic and multilocus sequence analyses (recA, rpoB and gyrB), as well as phylogenomic, chemotaxonomic and phenotypic tests, we demonstrate that strain Val9T represents a novel species of the genus Psychrobacillus, for which the name Psychrobacillus antarcticus sp. nov. is proposed. The type strain is Val9T (=DSM 115096T=CCGB 1952T=NRRL B-65674T).

Assuntos

RESUMO

An increasing number of systematic reviews (SR) has investigated the association between dental caries and nutritional status in children and adolescents, thus requiring an overview to compile the information in a single piece of evidence. Therefore, this study aimed to evaluate and summarize evidence from published SR on the association between dental caries and nutritional status in children and adolescents. A wide search was conducted on May 29, 2023, in six databases (Medline via PubMed, Scopus, Web of Science, Cochrane library, Embase, and the Virtual Health Library - VHL). An additional search was performed in the gray literature (Open grey and Google Scholar), SR registration databases, and the list of references of the included SR. Our inclusion criteria were based on acronym PECOS. Overall, two reviewers independently extracted the data, evaluated the risk of bias (ROBIS), and assessed the quality of the chosen studies (AMSTAR-2). Data from the included meta-analysis were summarized and certainty of evidence using the GRADE approach was performed. After removing duplicates and applying our eligibility criteria, 19 SR from 2006-2022 were included. We found that 17 SR showed high risk of bias and critically low methodological quality. We observed an association between dental caries experiences and nutritional status since seven SR found an association between obesity/overweight and dental caries; one, an association between underweight and dental caries; and eleven, no associations. The meta-analysis showed divergent results according to the study designs, used indices, and participants' age group, and were scored as having a very low certainty of evidence. Therefore, based on the high risk of bias, low methodological quality, and very low certainty of evidence of the chosen SR, most studies found no association between children and adolescents' nutritional status and dental caries experience.

Assuntos

RESUMO

Echinocandins, used for the prevention and treatment of invasive fungal infections, have led to a rise in breakthrough infections caused by resistant Candida species. Among these species, those belonging to the Candida haemulonii complex are rare multidrug-resistant (MDR) yeasts that are frequently misidentified but have emerged as significant healthcare-associated pathogens causing invasive infections. The objectives of this study were to investigate the evolutionary pathways of echinocandin resistance in C. haemulonii by identifying mutations in the FKS1 gene and evaluating the impact of resistance on fitness. After subjecting a MDR clinical isolate of C. haemulonii (named Ch4) to direct selection using increasing caspofungin concentrations, we successfully obtained an isolate (designated Ch4'r) that exhibited a high level of resistance, with MIC values exceeding 16 mg/L for all tested echinocandin drugs (caspofungin, micafungin, and anidulafungin). Sequence analysis revealed a specific mutation in the resistant Ch4'r strain, leading to an arginine-histidine amino acid substitution (R1354H), occurring at the G4061A position of the HS2 region of the FKS1 gene. Compared to the wild-type strain, Ch4'r exhibited significantly reduced growth proliferation, biofilm formation capability, and phagocytosis ratio, indicating a decrease in fitness. Transmission electron microscopy analysis revealed alterations in cell wall components, with a notable increase in cell wall thickness. The resistant strain also exhibited higher amounts (2.5-fold) of chitin, a cell wall-located molecule, compared to the wild-type strain. Furthermore, the resistant strain demonstrated attenuated virulence in the Galleria mellonella larval model. The evolved strain Ch4'r maintained its resistance profile in vivo since the treatment with either caspofungin or micafungin did not improve larval survival or reduce the fungal load. Taken together, our findings suggest that the acquisition of pan-echinocandin resistance occurred rapidly after drug exposure and was associated with a significant fitness cost in C. haemulonii. This is particularly concerning as echinocandins are often the first-line treatment option for MDR Candida species.

RESUMO

INTRODUCTION: Leishmaniasis is an important disease caused by parasites of the Leishmania. Due to the urgent need for financial incentives and research and development of new anti-Leishmania, a point that stands out is the creation of patents that comprise drugs and nanoformulations in treating the disease. AREAS COVERED: Information on individual patents and patent families containing potential drugs and nanoformulations were obtained by searching the Orbit software (QUESTEL SAS, France) using the following terms: Leishmania; treatment; nanoparticle*; drug×. The data obtained ranged from 2015 to 2022. EXPERT OPINION: Meglumine antimoniate is a pentavalent antimonial widely used in the classic treatment of leishmaniasis. It is part of the classic treatment recommended by WHO, being the first-choice drug globally about 75 years ago. Thus, the need to introduce new anti-Leishmania therapies into clinical medicine is evident since cases of resistance to monotherapy and multitherapy have increased greatly. Associated with this, the search for patents that are good candidates in treating this disease assues interest in investments of financial resources and raises a ray of hope for safe, effective, and low-cost therapies to become licensed for the treatment of leishmaniasis.

Assuntos

RESUMO

Magnetotactic bacteria (MTB), a diverse group of marine and freshwater microorganisms, have attracted the scientific community's attention since their discovery. These bacteria biomineralize ferrimagnetic nanocrystals, the magnetosomes, or biological magnetic nanoparticles (BMNs), in a single or multiple chain(s) within the cell. As a result, cells experience an optimized magnetic dipolar moment responsible for a passive alignment along the lines of the geomagnetic field. Advances in MTB cultivation and BMN isolation have contributed to the expansion of the biotechnological potential of MTB in recent decades. Several studies with mass-cultured MTB expanded the possibilities of using purified nanocrystals and whole cells in nano- and biotechnology. Freshwater MTB were primarily investigated in scaling up processes for the production of BMNs. However, marine MTB have the potential to overcome freshwater species applications due to the putative high efficiency of their BMNs in capturing molecules. Regarding the use of MTB or BMNs in different approaches, the application of BMNs in biomedicine remains the focus of most studies, but their application is not restricted to this field. In recent years, environment monitoring and recovery, engineering applications, wastewater treatment, and industrial processes have benefited from MTB-based biotechnologies. This review explores the advances in MTB large-scale cultivation and the consequent development of innovative tools or processes.

Assuntos

RESUMO

INTRODUCTION: Gastric cancer (GC) is the fifth most diagnosed neoplasia and the third leading cause of cancer-related deaths. A substantial number of patients exhibit an advanced GC stage once diagnosed. Therefore, the search for biomarkers contributes to the improvement and development of therapies. OBJECTIVE: This study aimed to identify potential GC biomarkers making use of in silico tools. METHODS: Gastric tissue microarray data available in Gene Expression Omnibus and The Cancer Genome Atlas Program was extracted. We applied statistical tests in the search for differentially expressed genes between tumoral and non-tumoral adjacent tissue samples. The selected genes were submitted to an in-house tool for analyses of functional enrichment, survival rate, histological and molecular classifications, and clinical follow-up data. A decision tree analysis was performed to evaluate the predictive power of the potential biomarkers. RESULTS: In total, 39 differentially expressed genes were found, mostly involved in extracellular structure organization, extracellular matrix organization, and angiogenesis. The genes SLC7A8, LY6E, and SIDT2 showed potential as diagnostic biomarkers considering the differential expression results coupled with the high predictive power of the decision tree models. Moreover, GC samples showed lower SLC7A8 and SIDT2 expression, whereas LY6E was higher. SIDT2 demonstrated a potential prognostic role for the diffuse type of GC, given the higher patient survival rate for lower gene expression. CONCLUSION: Our study outlines novel biomarkers for GC that may have a key role in tumor progression. Nevertheless, complementary in vitro analyses are still needed to further support their potential.

Assuntos