The two alternative NADH:quinone oxidoreductases from Staphylococcus aureus: two players with different molecular and cellular roles.

Staphylococcus aureus is an opportunistic pathogen that has emerged as a major public health threat due to the increased incidence of its drug resistance. S. aureus presents a remarkable capacity to adapt to different niches due to the plasticity of its energy metabolism. In this work, we investigated the energy metabolism of S. aureus, focusing on the alternative NADH:quinone oxidoreductases, NDH-2s. S. aureus presents two genes encoding NDH-2s (NDH-2A and NDH-2B) and lacks genes coding for Complex I, the canonical respiratory NADH:quinone oxidoreductase. This observation makes the action of NDH-2s crucial for the regeneration of NAD+ and, consequently, for the progression of metabolism. Our study involved the comprehensive biochemical characterization of NDH-2B and the exploration of the cellular roles of NDH-2A and NDH-2B, utilizing knockout mutants (Δndh-2a and Δndh-2b). We show that NDH-2B uses NADPH instead of NADH, does not establish a charge-transfer complex in the presence of NADPH, and its reduction by this substrate is the catalytic rate-limiting step. In the case of NDH-2B, the reduction of the flavin is inherently slow, and we suggest the establishment of a charge transfer complex between NADP+ and FADH2, as previously observed for NDH-2A, to slow down quinone reduction and, consequently, prevent the overproduction of reactive oxygen species, which is potentially unnecessary. Furthermore, we observed that the lack of NDH-2A or NDH-2B impacts cell growth, volume, and division differently. The absence of these enzymes results in distinct metabolic phenotypes, emphasizing the unique cellular roles of each NDH-2 in energy metabolism.IMPORTANCEStaphylococcus aureus is an opportunistic pathogen, posing a global challenge in clinical medicine due to the increased incidence of its drug resistance. For this reason, it is essential to explore and understand the mechanisms behind its resistance, as well as the fundamental biological features such as energy metabolism and the respective players that allow S. aureus to live and survive. Despite its prominence as a pathogen, the energy metabolism of S. aureus remains underexplored, with its respiratory enzymes often escaping thorough investigation. S. aureus bioenergetic plasticity is illustrated by its ability to use different respiratory enzymes, two of which are investigated in the present study. Understanding the metabolic adaptation strategies of S. aureus to bioenergetic challenges may pave the way for the design of therapeutic approaches that interfere with the ability of the pathogen to successfully adapt when it invades different niches within its host.

The monotopic quinone reductases from Staphylococcus aureus.

Staphylococcus aureus, a Gram-positive bacterium, is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial infections that has become a major public health threat due to the increased incidence of its drug resistance. Although being a prominent pathogen, its energetic metabolism is still underexplored, and its respiratory enzymes have been escaping attention. S. aureus can adapt to different environmental conditions by performing both aerobic and anaerobic respirations, which is particularly important as it frequently colonizes niches with different oxygen concentrations. This adaptability is derived from the composition of its respiratory chain, specifically from the presence of terminal electron acceptor reductases. The plasticity of S. aureus energy metabolism is enlarged by the ten quinone reductases encoded in its genome, eight of them being monotopic proteins. The role of these proteins is critical as they connect the different catabolic pathways to the respiratory chain. In this work, we identify, describe, and revise the monotopic quinone reductases present in S. aureus, providing an integrated view of its respiratory chain.

Exploring substrate interaction in respiratory alternative complex III from Rhodothermus marinus.

Rhodothermus marinus is a thermohalophilic organism that has optimized its microaerobic metabolism at 65 °C. We have been exploring its respiratory chain and observed the existence of a quinone:cytochrome c oxidoreductase complex, named Alternative Complex III, structurally different from the bc1 complex. In the present work, we took profit from nanodiscs and liposomes technology to investigate ACIII activity in membrane-mimicking systems. In addition, we studied the interaction of ACIII with menaquinone, its potential electron acceptors (HiPIP and cytochrome c) and the caa3 oxygen reductase.

The protein family of pyruvate:quinone oxidoreductases: Amino acid sequence conservation and taxonomic distribution.

Pyruvate:quinone oxidoreductases (PQOs) catalyse the oxidative decarboxylation of pyruvate to acetate and concomitant reduction of quinone to quinol with the release of CO2. They are thiamine pyrophosphate (TPP) and flavin-adenine dinucleotide (FAD) containing enzymes, which interact with the membrane in a monotopic way. PQOs are considered as part of alternatives to most recognized pyruvate catabolizing pathways, and little is known about their taxonomic distribution and structural/functional relationship. In this bioinformatics work we tackled these gaps in PQO knowledge. We used the KEGG database to identify PQO coding genes, performed a multiple sequence analysis which allowed us to study the amino acid conservation on these enzymes, and looked at their possible cellular function. We observed that PQOS are enzymes exclusively present in prokaryotes with most of the sequences identified in bacteria. Regarding the amino acid sequence conservation, we found that 75 amino acid residues (out of 570, on average) have a conservation over 90 %, and that the most conserved regions in the protein are observed around the TPP and FAD binding sites. We systematized the presence of conserved features involved in Mg2+, TPP and FAD binding, as well as residues directly linked to the catalytic mechanism. We also established the presence of a new motif named "HEH lock", possibly involved in the dimerization process. The results here obtained for the PQO protein family contribute to a better understanding of the biochemistry of these respiratory enzymes.

Unveiling the membrane bound dihydroorotate: Quinone oxidoreductase from Staphylococcus aureus.

Staphylococcus aureus is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial bacterial infections. Even so, its energy metabolism is still under explored and its respiratory enzymes have been vastly overlooked. In this work, we unveil the dihydroorotate:quinone oxidoreductase (DHOQO) from S. aureus, the first example of a DHOQO from a Gram-positive organism. This protein was shown to be a FMN containing menaquinone reducing enzyme, presenting a Michaelis-Menten behaviour towards the two substrates, which was inhibited by Brequinar, Leflunomide, Lapachol, HQNO, Atovaquone and TFFA with different degrees of effectiveness. Deletion of the DHOQO coding gene (Δdhoqo) led to lower bacterial growth rates, and effected in cell morphology and metabolism, most importantly in the pyrimidine biosynthesis, here systematized for S. aureus MW2 for the first time. This work unveils the existence of a functional DHOQO in the respiratory chain of the pathogenic bacterium S. aureus, enlarging the understanding of its energy metabolism.

Modularity of membrane-bound charge-translocating protein complexes.

Energy transduction is the conversion of one form of energy into another; this makes life possible as we know it. Organisms have developed different systems for acquiring energy and storing it in useable forms: the so-called energy currencies. A universal energy currency is the transmembrane difference of electrochemical potential (Δµ~). This results from the translocation of charges across a membrane, powered by exergonic reactions. Different reactions may be coupled to charge-translocation and, in the majority of cases, these reactions are catalyzed by modular enzymes that always include a transmembrane subunit. The modular arrangement of these enzymes allows for different catalytic and charge-translocating modules to be combined. Thus, a transmembrane charge-translocating module can be associated with different catalytic subunits to form an energy-transducing complex. Likewise, the same catalytic subunit may be combined with a different membrane charge-translocating module. In this work, we analyze the modular arrangement of energy-transducing membrane complexes and discuss their different combinations, focusing on the charge-translocating module.

The Ion-Translocating NrfD-Like Subunit of Energy-Transducing Membrane Complexes.

Several energy-transducing microbial enzymes have their peripheral subunits connected to the membrane through an integral membrane protein, that interacts with quinones but does not have redox cofactors, the so-called NrfD-like subunit. The periplasmic nitrite reductase (NrfABCD) was the first complex recognized to have a membrane subunit with these characteristics and consequently provided the family's name: NrfD. Sequence analyses indicate that NrfD homologs are present in many diverse enzymes, such as polysulfide reductase (PsrABC), respiratory alternative complex III (ACIII), dimethyl sulfoxide (DMSO) reductase (DmsABC), tetrathionate reductase (TtrABC), sulfur reductase complex (SreABC), sulfite dehydrogenase (SoeABC), quinone reductase complex (QrcABCD), nine-heme cytochrome complex (NhcABCD), group-2 [NiFe] hydrogenase (Hyd-2), dissimilatory sulfite-reductase complex (DsrMKJOP), arsenate reductase (ArrC) and multiheme cytochrome c sulfite reductase (MccACD). The molecular structure of ACIII subunit C (ActC) and Psr subunit C (PsrC), NrfD-like subunits, revealed the existence of ion-conducting pathways. We performed thorough primary structural analyses and built structural models of the NrfD-like subunits. We observed that all these subunits are constituted by two structural repeats composed of four-helix bundles, possibly harboring ion-conducting pathways and containing a quinone/quinol binding site. NrfD-like subunits may be the ion-pumping module of several enzymes. Our data impact on the discussion of functional implications of the NrfD-like subunit-containing complexes, namely in their ability to transduce energy.

Profile of non-suicidal self-injury in adolescents: interface with impulsiveness and loneliness

Abstract Objective: Comprehend the profile and prevalence of non-suicidal self-injury (NSSI) in adolescents and its association with impulsiveness and loneliness. Methods: Cross-sectional study carried out in 2017 in Maceió-Alagoas, Northeast Brazil, in the households of 505 adolescents aged 12-17 years, using a sample stratified and randomized by gender and neighborhood. The following instruments were used: a sociodemographic questionnaire, Brazilian version of Functional Assessment of Self-Mutilation (FASM), the Brazilian Barratt Impulsiveness Scale (BIS-11), and the Brazilian Loneliness Scale (UCLA-BR). Results: A prevalence of 6.53% was found for non-suicidal self-injury disorder (DSM-5). Significant differences ( p ≤ 0.05) were observed regarding: the most frequently used forms of NSSI were the items "cut oneself" and "scratch oneself"; engaging in three or more different forms of self-injurious behavior (66.67%) and, reporting as reasons, "to relieve feelings of emptiness or indifference" and "to stop bad feelings/sensations." Significance was also related to the sociodemographic profile: 72.73% were females and 63.54% had family income below one minimum wage. Individuals with self-injurious behavior also had higher impulsiveness and loneliness scores (p ≤ 0.05). Conclusions: The study identified a direct association between NSSI and impulsiveness and loneliness among adolescents, being more prevalent in females and in young individuals with socioeconomic vulnerability. The data provide support for improving public health policies, aimed at education, prevention, and treatment of adolescents with NSSI.

JPEG Pleno holography: scope and technology validation procedures.

JPEG Pleno is a standardization framework addressing the compression and signaling of plenoptic modalities. While the standardization of solutions to handle light field content is currently reaching its final stage, the Joint Photographic Experts Group (JPEG) committee is now preparing for the standardization of solutions targeting point cloud and holographic modalities. This paper addresses the challenges related to the standardization of compression technologies for holographic content and associated test methodologies.

Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins.

Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (ΔµÌƒ). Membrane proteins contribute to the establishment of ΔµÌƒ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.

Coarse-Grained Parameterization of Nucleotide Cofactors and Metabolites: Protonation Constants, Partition Coefficients, and Model Topologies.

Nucleotides are structural units relevant not only in nucleic acids but also as substrates or cofactors in key biochemical reactions. The size- and timescales of such nucleotide-protein interactions fall well within the scope of coarse-grained molecular dynamics, which holds promise of important mechanistic insight. However, the lack of specific parameters has prevented accurate coarse-grained simulations of protein interactions with most nucleotide compounds. In this work, we comprehensively develop coarse-grained parameters for key metabolites/cofactors (FAD, FMN, riboflavin, NAD, NADP, ATP, ADP, AMP, and thiamine pyrophosphate) in different oxidation and protonation states as well as for smaller molecules derived from them (among others, nicotinamide, adenosine, adenine, ribose, thiamine, and lumiflavin), summing up a total of 79 different molecules. In line with the Martini parameterization methodology, parameters were tuned to reproduce octanol-water partition coefficients. Given the lack of existing data, we set out to experimentally determine these partition coefficients, developing two methodological approaches, based on 31P-NMR and fluorescence spectroscopy, specifically tailored to the strong hydrophilicity of most of the parameterized compounds. To distinguish the partition of each relevant protonation species, we further potentiometrically characterized the protonation constants of key molecules. This work successfully builds a comprehensive and relevant set of computational models that will boost the biochemical application of coarse-grained simulations. It does so based on the measurement of partition and acid-base physicochemical data that, in turn, covers important gaps in nucleotide characterization.

Investigating the amino acid sequences of membrane bound dihydroorotate:quinone oxidoreductases (DHOQOs): Structural and functional implications.

Dihydroorotate:quinone oxidoreductases (DHOQOs) are membrane bound enzymes responsible for oxidizing dihydroorotate (DHO) to orotate with concomitant reduction of quinone to quinol. They have FMN as prosthetic group and are part of the monotopic quinone reductase superfamily. These enzymes are also members of the dihydroorotate dehydrogenases (DHODHs) family, which besides membrane bound DHOQOs, class 2, includes soluble enzymes which reduce either NAD+ or fumarate, class 1. As key enzymes in both the de novo pyrimidine biosynthetic pathway as well as in the energetic metabolism, inhibitors of DHOQOs have been investigated as leads for therapeutics in cancer, immunological disorders and bacterial/viral infections. This work is a thorough bioinformatic approach on the structural conservation and taxonomic distribution of DHOQOs. We explored previously established structural/functional hallmarks of these enzymes, while searching for uncharacterized common elements. We also discuss the cellular role of DHOQOs and organize the identified protein sequences within six sub-classes 2A to 2F, according to their taxonomic origin and sequence traits. We concluded that DHOQOs are present in Archaea, Eukarya and Bacteria, including the first recognition in Gram-positive organisms. DHOQOs can be the single dihydroorotate dehydrogenase encoded in the genome of a species, or they can coexist with other DHODHs, as the NAD+ or fumarate reducing enzymes. Furthermore, we show that the type of catalytic base present in the active site is not an absolute criterium to distinguish between class 1 and class 2 enzymes. We propose the existence of a quinone binding motif ("ExAH") adjacent to a hydrophobic cavity present in the membrane interacting N-terminal domain.

Profile of non-suicidal self-injury in adolescents: interface with impulsiveness and loneliness.

OBJECTIVE: Comprehend the profile and prevalence of non-suicidal self-injury (NSSI) in adolescents and its association with impulsiveness and loneliness. METHODS: Cross-sectional study carried out in 2017 in Maceió-Alagoas, Northeast Brazil, in the households of 505 adolescents aged 12-17 years, using a sample stratified and randomized by gender and neighborhood. The following instruments were used: a sociodemographic questionnaire, Brazilian version of Functional Assessment of Self-Mutilation (FASM), the Brazilian Barratt Impulsiveness Scale (BIS-11), and the Brazilian Loneliness Scale (UCLA-BR). RESULTS: A prevalence of 6.53% was found for non-suicidal self-injury disorder (DSM-5). Significant differences ( p ≤ 0.05) were observed regarding: the most frequently used forms of NSSI were the items "cut oneself" and "scratch oneself"; engaging in three or more different forms of self-injurious behavior (66.67%) and, reporting as reasons, "to relieve feelings of emptiness or indifference" and "to stop bad feelings/sensations." Significance was also related to the sociodemographic profile: 72.73% were females and 63.54% had family income below one minimum wage. Individuals with self-injurious behavior also had higher impulsiveness and loneliness scores (p ≤ 0.05). CONCLUSIONS: The study identified a direct association between NSSI and impulsiveness and loneliness among adolescents, being more prevalent in females and in young individuals with socioeconomic vulnerability. The data provide support for improving public health policies, aimed at education, prevention, and treatment of adolescents with NSSI.

Amphibians and reptiles from the Parque Nacional da Tijuca, Brazil, one of the world's largest urban forests / Anfíbios e répteis do Parque Nacional da Tijuca, Brasil, uma das maiores florestas urbanas do mundo

Abstract: The Parque Nacional da Tijuca in Rio de Janeiro, Brazil, is considered to be one of the world's largest urban forests, however no systematic inventory of its herpetofauna is available. In the present study, we surveyed the amphibians and reptiles of this park to assess its species composition (including secondary data) and obtain estimates of species richness and abundance. We conducted active searches (460 hours) between January 2013 and December 2015. We identified the taxa endemic to either the Atlantic Forest or Rio de Janeiro state, and verified the conservation status of each species in the international, Brazilian, and state red lists. We also estimated the species richness and sampling sufficiency by rarefaction curves and Bootstrap richness estimator, and analyzed the distribution of the species abundance in Whittaker plots. We recorded 3,288 individuals over 36 months, representing 24 species of amphibians and 25 reptiles. The cumulative species curves, rarefaction, and the richness estimated indicated that sampling effort was adequate. Species abundance adjusted to the log-series model in both amphibians and reptiles. The four most abundant amphibians represented 70% of the individuals recorded in this group, while the two most abundant reptiles represented 60% of the total individuals. The inclusion of the secondary data raised the number of amphibian species to 38, and the number of reptiles to 36. Approximately 80% of the amphibian species and 28% of the reptile species recorded are endemic to the Atlantic Forest, and six of the amphibian species are endemic to Rio de Janeiro state. Six amphibian species and one reptile species are classified under some threat of extinction, and two reptile species were exotic. The considerable diversity of the herpetofauna of the Parque Nacional da Tijuca, which includes endemic and threatened species, reflects the effectiveness of the reforestation of this protected area and emphasizes the importance of its conservation.

Resumo: O Parque Nacional da Tijuca, no Rio de Janeiro, Brasil, é considerado uma das maiores florestas urbanas do mundo, no entanto nenhum inventário sistemático de sua herpetofauna está disponível. No presente estudo, pesquisamos os anfíbios e répteis deste parque para acessar sua composição de espécies (incluindo dados secundários) e obter estimativas da riqueza e da abundância de espécies. Realizamos buscas ativas (460 horas) entre janeiro de 2013 e dezembro de 2015. Identificamos os taxa endêmicos da Mata Atlântica ou do estado do Rio de Janeiro, e verificamos o status de conservação de cada espécie nas listas vermelhas internacional, brasileira e estadual. Também estimamos a riqueza de espécies e a suficiência amostral através de curvas de rarefação e do estimador de riqueza Bootstrap, e analisamos a distribuição de abundância das espécies através de plots de Whittaker. Registramos 3.288 indivíduos ao longo dos 36 meses, representando 24 espécies de anfíbios e 25 de répteis. As curvas cumulativas de espécies, a rarefação, e a riqueza estimada indicaram que o esforço amostral foi adequado. A abundância das espécies se ajustou ao modelo de série logarítmica tanto para os anfíbios como para os répteis. As quatro espécies de anfíbios mais abundantes representaram 70% dos indivíduos registrados neste grupo, enquanto as duas espécies de répteis mais abundantes representaram 60% do total de indivíduos. A inclusão dos dados secundários elevou o número de espécies de anfíbios para 38 e o de répteis para 36. Aproximadamente 80% dos anfíbios e 28% dos répteis registrados são endêmicos da Mata Atlântica e seis espécies de anfíbios são endêmicos do estado do Rio de Janeiro. Seis espécies de anfíbios e uma de réptil estão classificadas sob alguma ameaça de extinção, e dois répteis constituem espécies exóticas. A considerável diversidade da herpetofauna do Parque Nacional da Tijuca, que inclui espécies endêmicas e ameaçadas, reflete a efetividade do reflorestamento dessa área protegida e enfatiza a importância de sua conservação.

Anurans of a remnant of Mixed Rainforest in southern Brazil / Anuros de um remanescente de Floresta Ombrófila Mista no sul do Brasil

Abstract: The Brazilian Atlantic Forest is one of the world's most biodiverse biomes, with large numbers of endemic and threatened species. However, this biome has suffered extensive deforestation and habitat fragmentation, with a drastic reduction of its original vegetation cover. The compilation of data on the occurrence patterns of anurans and their natural history is important for the development of effective conservation strategies. Here, we present the results of a survey of the anuran fauna of Parque Estadual do Papagaio Charão (PEPC) in Rio Grande do Sul state, southern Brazil, providing information on species endemism, conservation status, and reproductive modes. We collected data on the local anurans between March 2018 and February 2019 using active searches and pitfall traps. We recorded 26 anuran species distributed in seven families, with eight different reproductive modes. The largest number of species (20) was found at the forest edge, followed by the interior of the forest and open area, each with 16 species. The most abundant species were Leptodactylus plaumanni (41.7% of records), Physalaemus cuvieri (27.1%), and P. carrizorum (16.5%). Greater species richness and abundance were recorded during the rainier months, while temperature influenced only the abundance of the anurans. Rhinella henseli, Rhinella icterica, Vitreorana uranoscopa, Aplastodiscus perviridis, Boana curupi, Boana leptolineata and Proceratophrys brauni are all endemic to the Atlantic Forest. Melanophryniscus devincenzii is classified as Endangered by the IUCN, and Proceratophrys bigibbosa as Near Threatened. Boana curupi is considered to be Endangered in Rio Grande do Sul state, and Vulnerable in Brazil, while V. uranoscopa is Near Threatened in Rio Grande do Sul. Our findings emphasize the importance of protected areas, such as the PEPC, for the maintenance of anuran populations and communities in the Mixed Rainforest formations of southern Brazil.

Resumo: A Mata Atlântica abriga a maior biodiversidade do planeta, com elevados números de endemismos e espécies ameaçadas de extinção. Entretanto, esse bioma tem sofrido extensa perda e fragmentação do habitat, com redução drástica da sua cobertura vegetacional original. Suprir lacunas sobre a história natural e os padrões de ocorrências de anuros auxiliam no desenvolvimento de estratégias de conservação para esse grupo. Neste estudo apresentamos a anurofauna do Parque Estadual do Papagaio Charão (PEPC), no estado do Rio Grande do Sul, sul do Brasil, com informações sobre endemismos, status de conservação e modos reprodutivos das espécies. Nossas amostragens em campo ocorreram entre março de 2018 e fevereiro de 2019 e utilizamos procura ativa e pitfalls traps para a coleta dos anuros. Registramos 26 espécies de anuros distribuídas em sete famílias e oito modos reprodutivos. Um número maior de espécies foi encontrado na borda (20 espécies), seguida da floresta e área aberta (16 espécies cada). As espécies mais abundantes foram Leptodactylus plaumanni (41,7%), Physalaemus cuvieri (27,1%) e P. carrizorum (16,5%). Maior riqueza e abundância foram registradas no período com maior pluviosidade e a temperatura influenciou somente a abundância dos anuros. Rhinella henseli, R. icterica, Vitreorana uranoscopa, Aplastodiscus perviridis, Boana curupi, B. leptolineata e Proceratophrys brauni são endêmicas da Mata Atlântica. Melanophryniscus devincenzii está classificada como "Em perigo" e Proceratophrys bigibbosa como "Quase ameaçada" pela IUCN. Boana curupi é considerada "Em perigo" no estado do Rio Grande do Sul e "Vulnerável" no Brasil. Vitreorana uranoscopa consta como "Quase ameaçada" no Rio Grande do Sul. Nossos resultados mostram a importância de áreas protegidas, como o PEPC, para a manutenção das populações e comunidades de anuros da Floresta Ombrófila Mista.

Assessment of speckle denoising filters for digital holography using subjective and objective evaluation models.

Digital holography is an emerging imaging technique for displaying and sensing three-dimensional objects. The perceived image quality of a hologram is frequently corrupted by speckle noise due to coherent illumination. Although several speckle noise reduction methods have been developed so far, there are scarce quality assessment studies to address their performance, and they typically focus solely on objective metrics. However, these metrics do not reflect the visual quality perceived by a human observer. In this work, the performances of four speckle reduction algorithms, namely, the nonlocal means-the Lee, the Frost, and the block-matching 3D filters, with varying parameterizations-were subjectively evaluated. The results were ranked with respect to the perceived image quality to obtain the mean opinion scores using pairwise comparison. The correlation between the subjective results and 20 different no-reference objective quality metrics was evaluated. The experiment indicates that block-matching 3D and Lee are the preferred filters, depending on hologram characteristics. The best-performing objective metrics were identified for each filter.

The plethora of membrane respiratory chains in the phyla of life.

The diversity of microbial cells is reflected in differences in cell size and shape, motility, mechanisms of cell division, pathogenicity or adaptation to different environmental niches. All these variations are achieved by the distinct metabolic strategies adopted by the organisms. The respiratory chains are integral parts of those strategies especially because they perform the most or, at least, most efficient energy conservation in the cell. Respiratory chains are composed of several membrane proteins, which perform a stepwise oxidation of metabolites toward the reduction of terminal electron acceptors. Many of these membrane proteins use the energy released from the oxidoreduction reaction they catalyze to translocate charges across the membrane and thus contribute to the establishment of the membrane potential, i.e. they conserve energy. In this work we illustrate and discuss the composition of the respiratory chains of different taxonomic clades, based on bioinformatic analyses and on biochemical data available in the literature. We explore the diversity of the respiratory chains of Animals, Plants, Fungi and Protists kingdoms as well as of Prokaryotes, including Bacteria and Archaea. The prokaryotic phyla studied in this work are Gammaproteobacteria, Betaproteobacteria, Epsilonproteobacteria, Deltaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Chlamydiae, Verrucomicrobia, Acidobacteria, Planctomycetes, Cyanobacteria, Bacteroidetes, Chloroflexi, Deinococcus-Thermus, Aquificae, Thermotogae, Deferribacteres, Nitrospirae, Euryarchaeota, Crenarchaeota and Thaumarchaeota.

Perfil de resistência da Escherichia coli, isoladas de água e ostras, aos betalactâmicos / Profile resistance of Escherichia coli, isolated from water and oysters, to betalactams

Com o objetivo de avaliar o grau de contaminação por coliformes presentes na água e em ostras e isolar cepas de Escherichia coli para testar seu perfil de resistência aos antibióticos β-lactâmicos, foram coletadas amostras de água e ostras nas regiões de Baixão de Guaí e Capanema, Estuário da Baía do Iguape, BA. A partir das análises microbiológicas de contagem de coliformes à 35ºC e 45ºC, cepas de E. coli foram isoladas e identificadas para realização dos testes de suscetibilidade aos antimicrobianos pertencentes a família dos β-lactâmicos – amoxicilina (10μg), ampicilina (10μg), azetronan (30μg), imipenem (10μg), cefalotina (30μg), ceftriaxona (30μg), oxacilina (1μg), utilizando a técnica de difusão de disco em placas. Foi verificado que todos os isolados apresentaram resistência à oxacilina, em contrapartida 100% das cepas de E. coli avaliadas demonstraram perfil de sensibilidade à azetronam, seguidas por 97% ao imepenem e ceftriaxona e 90% à ampicilina.