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1.
Artigo em Inglês | MEDLINE | ID: mdl-39228122

RESUMO

AIM: To evaluate the efficacy of guided bone regeneration (GBR) for the treatment of peri-implant dehiscence defects using a synthetic bone substitute (SBS) or a deproteinized bovine bone mineral (DBBM) as a bone substitute. METHODS: Patients with expected dehiscence defects following implant placement were randomized to use either SBS or DBBM together with a bioabsorbable collagen membrane over dehiscenced implant surfaces aimed for GBR. The changes in the bone defect size were measured before the GBR procedure and 6 months after implant placement at the re-entry surgery. Secondary outcomes included peri-implant health outcomes, implant cumulative survival rates, bone level changes, and patient-reported outcomes (PROMs) at prosthesis delivery and 1-year follow-up. RESULTS: Of the 49 included patients, 24 were treated with SBS and 25 with DBBM. In the SBS group, the defect height (DH) at implant insertion was 5.1 ± 2.6 mm and was reduced at re-entry to 1.3 ± 2.0 mm (74.5%). In the DBBM group, the respective changes in DH were 4.1 ± 1.7 mm and 1.5 ± 1.9 mm (63.4%). These differences were not statistically significant (p = 0.216). The complete defect resolution rate was also comparable in both groups without statistical difference (62.5% of patients (15/24) vs. 44% of patients (11/25)). Overall, the marginal bone levels remained stable during the 1-year follow-up in both groups. CONCLUSION: The SBS is noninferior to DBBM for simultaneous GBR to implant placement at implant sites with buccal dehiscences in terms of defect resolution and evaluated secondary outcomes (KCT0008393 - this clinical trial was not registered before participant recruitment and randomization).

3.
Nutrients ; 16(16)2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39203924

RESUMO

Essential trace minerals are vital for general human health and athletic performance. Zinc (Zn) plays critical roles in several biochemical processes in exercise physiology, especially during intense physical exercise. This research aimed to analyze erythrocyte, platelet, plasma and urine Zn concentrations among men's and female soccer players over a sports season. A total of 22 male soccer players (20.61 ± 2.66 years; 71.50 ± 5.93 kg) and 24 female soccer players (23.37 ± 3.95 years; 59.58 ± 7.17 kg) participated in this longitudinal quasi-experimental study. Three assessments were carried out over the season: 1st evaluation: first week of training (August); 2nd assessment: middle of the season, between the end of the first and second round (January) and 3rd assessment: last week of training (May/June). In all evaluations extracellular (plasma and urine) and intracellular (erythrocytes and platelets) Zn concentrations were determined, as well as physical fitness and several blood parameters. Inductively coupled plasma mass spectrometry was used to measure Zn concentrations. Plasma and urinary concentrations were higher among male soccer players (p < 0.05) while erythrocyte and platelet Zn concentrations were higher in the female soccer players (p < 0.05). Additionally, variations in urinary and platelet Zn concentrations were observed over the season. The differences could be related to muscle mass, muscle damage or the specific sport's physical demands.


Assuntos
Plaquetas , Eritrócitos , Futebol , Zinco , Humanos , Futebol/fisiologia , Zinco/sangue , Zinco/urina , Feminino , Masculino , Adulto Jovem , Eritrócitos/metabolismo , Eritrócitos/química , Plaquetas/metabolismo , Adulto , Atletas , Estudos Longitudinais , Adolescente , Aptidão Física/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-39011816

RESUMO

OBJECTIVE: The aim of this investigation was to evaluate the effect on clinical and radiological outcomes of the one-abutment, one-time protocol (test) versus placing the definitive abutment on the day of functional loading after having disconnected and connected three times the healing abutment during the prosthetic phase (control). MATERIALS AND METHODS: Forty patients with 80 implants were randomly allocated to either the test or the control group. Changes in the radiographic marginal bone levels (MBLs), clinical outcomes, prosthetic-related outcomes, and patient-reported outcomes measures (PROMs) were assessed and compared 6 and 12 months after functional loading. RESULTS: Thirty-seven patients with 74 implants were followed at 12 months. A statistically significant bone remodeling was observed in both groups following implant placement. MBLs were significantly greater in the control group at the 6- (-0.13 mm vs. -0.61 mm) and 12-month visits (-0.01 mm vs. -0.53 mm). Bone loss was significantly greater in the control group from surgery to 6 and 12 months and from loading to 6 and 12 months. The abutment height was significantly greater in the test group, however, there were no significant differences in the restorative angle. Similarly, there were no statistically significant differences between groups for the measured clinical variables (probing depth, plaque, and bleeding index) and PROMs. CONCLUSIONS: Disconnecting and reconnecting the healing abutment was associated with significantly higher bone loss after 12 months, as compared to the placement of the definitive abutment at implant installation.

5.
J Dent ; 148: 105131, 2024 09.
Artigo em Inglês | MEDLINE | ID: mdl-38950765

RESUMO

OBJECTIVES: Digital protocols and bioactive materials may reduce complications and improve tooth autotransplantation (ATT) success and survival rates. This prospective study assesses the performance of a fully digital autotransplantation protocol of close-apex molars with the adjunctive application of Enamel Matrix Derivatives (EMD). METHODS: Twelve adult patients with 13 hopeless molar teeth were replaced with autotransplantation of closed apex third molars. Outcomes, including success and survival rates, clinical, endodontic, radiographic, patient-reported outcome measures (PROMs), and digital image assessments, were conducted over a two-year follow-up period. RESULTS: Survival and success rates were 100% and 91.2%, respectively, with no progressive inflammatory or replacement root resorption (ankylosis) except for one tooth presenting radiographic furcation involvement. A significant probing depth reduction of 2.4 ± 2.58 mm and CAL gains of 2.8 ± 3.03 mm were observed in transplanted teeth compared to the hopeless receptor teeth. Radiographic bone levels remained stable throughout the study period (-0.37 ± 0.66 mm), and digital image assessments showed minimal alveolar ridge width changes (-0.32 to -0.7 mm) and gingival margin changes (-0.95 to -1.27 mm) from baseline to last visit. PROMs indicated very high patient satisfaction. CONCLUSION: The use of a digital ATT protocol with adjunctive use of EMD in closed-apex third molars demonstrated promising short-term high success and survival rates. Additionally, this type of therapy adequately preserves the dimensions of the alveolar ridge in the receptor site. CLINICAL SIGNIFICANCE: This is the first prospective clinical study examining the effect of a digital tooth autotransplantation protocol combined with the application of EMD. It demonstrates that this approach is an effective treatment for replacing hopeless teeth and also validates the digital assessment of ATT alveolar ridge preservation at the recipient site.


Assuntos
Proteínas do Esmalte Dentário , Transplante Autólogo , Humanos , Estudos Prospectivos , Feminino , Adulto , Masculino , Pessoa de Meia-Idade , Proteínas do Esmalte Dentário/uso terapêutico , Resultado do Tratamento , Dente Serotino/transplante , Dente Serotino/diagnóstico por imagem , Fluxo de Trabalho , Adulto Jovem , Tomografia Computadorizada de Feixe Cônico , Medidas de Resultados Relatados pelo Paciente , Dente Molar
6.
Biology (Basel) ; 13(7)2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-39056663

RESUMO

Glucotoxicity may exert its deleterious effects on pancreatic ß-cell function via a myriad of mechanisms, leading to impaired insulin secretion and, eventually, type 2 diabetes. ß-cell communication requires gap junction channels to be present among these cells. Gap junctions are constituted by transmembrane proteins of the connexins (Cxs) family. Two Cx genes have been identified in ß cells, Cx36 and Cx30.2. We have found evidence that the glucose concentration on its own is sufficient to regulate Cx30.2 gene expression in mouse islets. In this work, we examine the involvement of the Cx30.2 protein in the survival of ß cells (RIN-m5F). METHODS: RIN-m5F cells were cultured in 5 mM D-glucose (normal) or 30 mM D-glucose (high glucose) for 24 h. Cx30.2 siRNAs was used to downregulate Cx30.2 expression. Apoptosis was measured by means of TUNEL, an annexin V staining method, and the cleaved form of the caspase-3 protein was determined using Western blot. RESULTS: High glucose did not induce apoptosis in RIN-m5F ß cells after 24 h; interestingly, high glucose increased the Cx30.2 total protein levels. Moreover, this work found that the downregulation of Cx30.2 expression in high glucose promoted apoptosis in RIN-m5F cells. CONCLUSION: The data suggest that the upregulation of Cx30.2 protects ß cells from hyperglycemia-induced apoptosis. Furthermore, Cx30.2 may be a promising avenue of therapeutic investigation for the treatment of glucose metabolic disorders.

7.
Nutrients ; 16(12)2024 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-38931250

RESUMO

Fatty acids (FAs) are an essential component of the erythrocyte membrane, and nutrition and physical exercise are two variables that affect their structure and function. The aim of this study was to evaluate the erythrocyte profile in a group of high-level endurance runners, as well as the changes in different FAs, throughout a sports season in relation to the training performed. A total of 21 high-level male endurance runners (23 ± 4 years; height: 1.76 ± 0.05) were evaluated at four different times throughout a sports season. The athletes had at least 5 years of previous experience and participated in national and international competitions. The determination of the different FAs was carried out by gas chromatography. The runners exhibited low concentrations of docosahexaenoic acid (DHA) and omega-3 index (IND ω-3), as well as high values of stearic acid (SA), palmitic acid (PA), and arachidonic acid (AA), compared to the values of reference throughout the study. In conclusion, training modifies the erythrocyte FA profile in high-level endurance runners, reducing the concentrations of polyunsaturated fatty acids (PUFAs) such as DHA and AA and increasing the concentrations of saturated fatty acids (SFAs) such as SA and the PA. High-level endurance runners should pay special attention to the intake of PUFAs ω-3 in their diet or consider supplementation during training periods to avoid deficiency.


Assuntos
Atletas , Eritrócitos , Ácidos Graxos , Resistência Física , Corrida , Humanos , Masculino , Corrida/fisiologia , Eritrócitos/metabolismo , Eritrócitos/química , Ácidos Graxos/sangue , Resistência Física/fisiologia , Adulto , Adulto Jovem , Atletas/estatística & dados numéricos , Ácidos Docosa-Hexaenoicos/sangue , Ácidos Graxos Ômega-3/sangue , Ácido Araquidônico/sangue , Estações do Ano , Ácido Palmítico/sangue
8.
Proc Natl Acad Sci U S A ; 121(21): e2318905121, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38739787

RESUMO

We propose that spontaneous folding and molecular evolution of biopolymers are two universal aspects that must concur for life to happen. These aspects are fundamentally related to the chemical composition of biopolymers and crucially depend on the solvent in which they are embedded. We show that molecular information theory and energy landscape theory allow us to explore the limits that solvents impose on biopolymer existence. We consider 54 solvents, including water, alcohols, hydrocarbons, halogenated solvents, aromatic solvents, and low molecular weight substances made up of elements abundant in the universe, which may potentially take part in alternative biochemistries. We find that along with water, there are many solvents for which the liquid regime is compatible with biopolymer folding and evolution. We present a ranking of the solvents in terms of biopolymer compatibility. Many of these solvents have been found in molecular clouds or may be expected to occur in extrasolar planets.


Assuntos
Solventes , Biopolímeros/química , Solventes/química , Meio Ambiente Extraterreno/química , Evolução Molecular , Água/química
9.
J Clin Periodontol ; 51(8): 968-980, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38690660

RESUMO

AIM: To evaluate the effectiveness of a flapless surgical approach in the treatment of peri-implantitis and to explore the factors influencing its outcome. MATERIALS AND METHODS: The present retrospective study evaluated patients with at least one implant diagnosed with peri-implantitis and treated with a flapless surgical access, with or without systemic antimicrobials, curettage and, when needed, prostheses modification. Clinical and radiographic parameters were assessed at baseline and at 3 months and at least 12 months. The primary outcome was disease resolution (≤1 bleeding sites, probing depth [PD] ≤5 mm, no bone loss >0.5 mm). Multilevel regression analyses were used to identify predictors influencing the probability of attaining disease resolution. RESULTS: One hundred and seventeen patients with 338 implants were included. Disease resolution was attained in 54.4% of the 338 implants receiving flapless surgical access. At the end of the follow-up period, 111 patients (94.9%) with 295 implants (87.3%) did not require any further treatment, with 81.4% of these implants presenting PD ≤ 5 mm. History of periodontitis and PD at baseline were identified as negative predictors, while compliance with supportive peri-implant care, a machined surface and the adjunctive use of systemic azithromycin or metronidazole were identified as positive predictive factors for disease resolution. CONCLUSIONS: A flapless surgical approach led to disease resolution in 54.4% of the implants with peri-implantitis. Several risk/protective predictors for disease resolution were identified.


Assuntos
Antibacterianos , Implantes Dentários , Peri-Implantite , Humanos , Peri-Implantite/cirurgia , Estudos Retrospectivos , Masculino , Feminino , Pessoa de Meia-Idade , Antibacterianos/uso terapêutico , Antibacterianos/administração & dosagem , Idoso , Resultado do Tratamento , Descontaminação/métodos , Adulto
10.
Nat Commun ; 15(1): 4163, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755145

RESUMO

TAR DNA-binding protein 43 (TDP-43) proteinopathy in brain cells is the hallmark of amyotrophic lateral sclerosis (ALS) but its cause remains elusive. Asparaginase-like-1 protein (ASRGL1) cleaves isoaspartates, which alter protein folding and susceptibility to proteolysis. ASRGL1 gene harbors a copy of the human endogenous retrovirus HML-2, whose overexpression contributes to ALS pathogenesis. Here we show that ASRGL1 expression was diminished in ALS brain samples by RNA sequencing, immunohistochemistry, and western blotting. TDP-43 and ASRGL1 colocalized in neurons but, in the absence of ASRGL1, TDP-43 aggregated in the cytoplasm. TDP-43 was found to be prone to isoaspartate formation and a substrate for ASRGL1. ASRGL1 silencing triggered accumulation of misfolded, fragmented, phosphorylated and mislocalized TDP-43 in cultured neurons and motor cortex of female mice. Overexpression of ASRGL1 restored neuronal viability. Overexpression of HML-2 led to ASRGL1 silencing. Loss of ASRGL1 leading to TDP-43 aggregation may be a critical mechanism in ALS pathophysiology.


Assuntos
Esclerose Lateral Amiotrófica , Asparaginase , Proteínas de Ligação a DNA , Neurônios , Proteinopatias TDP-43 , Animais , Feminino , Humanos , Masculino , Camundongos , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Asparaginase/genética , Asparaginase/metabolismo , Autoantígenos/genética , Autoantígenos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Córtex Motor/metabolismo , Córtex Motor/patologia , Neurônios/metabolismo , Neurônios/patologia , Proteinopatias TDP-43/metabolismo , Proteinopatias TDP-43/patologia , Proteinopatias TDP-43/genética , Retrovirus Endógenos/genética , Retrovirus Endógenos/metabolismo
11.
BMC Microbiol ; 24(1): 129, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38643099

RESUMO

The α-Proteobacteria belonging to Bradyrhizobium genus are microorganisms of extreme slow growth. Despite their extended use as inoculants in soybean production, their physiology remains poorly characterized. In this work, we produced quantitative data on four different isolates: B. diazoefficens USDA110, B. diazoefficiens USDA122, B. japonicum E109 and B. japonicum USDA6 which are representative of specific genomic profiles. Notably, we found conserved physiological traits conserved in all the studied isolates: (i) the lag and initial exponential growth phases display cell aggregation; (ii) the increase in specific nutrient concentration such as yeast extract and gluconate hinders growth; (iii) cell size does not correlate with culture age; and (iv) cell cycle presents polar growth. Meanwhile, fitness, cell size and in vitro growth widely vary across isolates correlating to ribosomal RNA operon number. In summary, this study provides novel empirical data that enriches the comprehension of the Bradyrhizobium (slow) growth dynamics and cell cycle.


Assuntos
Bradyrhizobium , Bradyrhizobium/genética , Bradyrhizobium/metabolismo , Glycine max , Fenômenos Fisiológicos Celulares , Fenótipo , Simbiose
12.
Arch Biochem Biophys ; 755: 109979, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38583654

RESUMO

Although protein sequences encode the information for folding and function, understanding their link is not an easy task. Unluckily, the prediction of how specific amino acids contribute to these features is still considerably impaired. Here, we developed a simple algorithm that finds positions in a protein sequence with potential to modulate the studied quantitative phenotypes. From a few hundred protein sequences, we perform multiple sequence alignments, obtain the per-position pairwise differences for both the sequence and the observed phenotypes, and calculate the correlation between these last two quantities. We tested our methodology with four cases: archaeal Adenylate Kinases and the organisms optimal growth temperatures, microbial rhodopsins and their maximal absorption wavelengths, mammalian myoglobins and their muscular concentration, and inhibition of HIV protease clinical isolates by two different molecules. We found from 3 to 10 positions tightly associated with those phenotypes, depending on the studied case. We showed that these correlations appear using individual positions but an improvement is achieved when the most correlated positions are jointly analyzed. Noteworthy, we performed phenotype predictions using a simple linear model that links per-position divergences and differences in the observed phenotypes. Predictions are comparable to the state-of-art methodologies which, in most of the cases, are far more complex. All of the calculations are obtained at a very low information cost since the only input needed is a multiple sequence alignment of protein sequences with their associated quantitative phenotypes. The diversity of the explored systems makes our work a valuable tool to find sequence determinants of biological activity modulation and to predict various functional features for uncharacterized members of a protein family.

14.
Clin Oral Implants Res ; 35(6): 609-620, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38506392

RESUMO

OBJECTIVE: The aim of this study was to evaluate the long-term (5 years) clinical efficacy of the one-abutment one-time protocol (test) versus the standard of care by placing the definitive abutment on the day of the prosthetic delivery (control). MATERIALS AND METHODS: In this study, 39 subjects with 60 implants were randomly allocated to either the test or the control group. Changes in the radiographic interproximal bone levels (DIB), modified sulcus bleeding index, probing depth, modified plaque index, papilla fill (Jemt score), incidence of peri-implantitis and peri-implant mucositis as well as patient-reported outcomes measures (PROMs) were collected and compared at 1, 3 and 5 years. RESULTS: At 5 years, the control group showed a greater, although not statistically significant, change in mean DIB values (0.97 mm vs. 0.53 mm). Regarding the other clinical parameters evaluated, no statistically significant differences were observed between groups at any time point. At 5 years, 51% of the implants presented peri-implant mucositis (25.5% in the control and 23.5% in the test), and only one implant in the test group developed peri-implantitis. CONCLUSIONS: The connection and disconnection of healing abutments during the healing period was not associated with higher long-term bone loss. Clinical outcomes and PROMs were similar between groups.


Assuntos
Dente Suporte , Peri-Implantite , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Dente Suporte/efeitos adversos , Peri-Implantite/diagnóstico por imagem , Resultado do Tratamento , Índice Periodontal , Implantação Dentária Endóssea/métodos , Implantação Dentária Endóssea/efeitos adversos , Perda do Osso Alveolar/diagnóstico por imagem , Adulto , Idoso , Medidas de Resultados Relatados pelo Paciente , Implantes Dentários/efeitos adversos , Índice de Placa Dentária
16.
J Chem Inf Model ; 63(22): 7228-7238, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37947759

RESUMO

Carbendazim derivatives, commonly used as antiparasitic drugs, have shown potential as anticancer agents due to their ability to induce cell cycle arrest and apoptosis in human cancer cells by inhibiting tubulin polymerization. Crystallographic structures of α/ß-tubulin multimers complexed with nocodazole and mebendazole, two carbendazim derivatives with potent anticancer activity, highlighted the possibility of designing compounds that occupy both benzimidazole- and colchicine-binding sites. In addition, previous studies have demonstrated that the incorporation of a phenoxy group at position 5/6 of carbendazim increases the antiproliferative activity in cancer cell lines. Despite the significant progress made in identifying new tubulin-targeting anticancer compounds, further modifications are needed to enhance their potency and safety. In this study, we explored the impact of modifying the phenoxy substitution pattern on antiproliferative activity. Alchemical free energy calculations were used to predict the binding free energy difference upon ligand modification and define the most viable path for structure optimization. Based on these calculations, seven compounds were synthesized and evaluated against lung and colon cancer cell lines. Our results showed that compound 5a, which incorporates an α-naphthyloxy substitution, exhibits the highest antiproliferative activity against both cancer lines (SK-LU-1 and SW620, IC50 < 100 nM) and induces morphological changes in the cells associated with mitotic arrest and mitotic catastrophe. Nevertheless, the tubulin polymerization assay showed that 5a has a lower inhibitory potency than nocodazole. Molecular dynamics simulations suggested that this low antitubulin activity could be associated with the loss of the key H-bond interaction with V236. This study provides insights into the design of novel carbendazim derivatives with anticancer activity.


Assuntos
Antineoplásicos , Moduladores de Tubulina , Humanos , Moduladores de Tubulina/química , Estrutura Molecular , Relação Estrutura-Atividade , Nocodazol/farmacologia , Tubulina (Proteína)/metabolismo , Proliferação de Células , Simulação de Acoplamento Molecular , Antineoplásicos/farmacologia , Antineoplásicos/química , Polimerização , Ensaios de Seleção de Medicamentos Antitumorais
17.
Nat Prod Res ; : 1-9, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37932254

RESUMO

5α,8α-peroxyergosteryl divaricatinate (1) is isolated for the first time from acetone extract of the thallus of Cladonia cf. didyma together with condidymic (2), isodidymic (3) and barbatic (4) acids. Their UVB/UVA photoprotective and antioxidant activities were determined along with their cyto- and DNA-protecting actions against OH• damage. Compound 1 showed high UVA, cyto- (%cell viability ca. 82 at 15 µM vs 71 for OH•) and DNA (%DNA-integrity ca. 74 at 100 µM vs 22 for OH•) protecting properties. Compounds 2 and 3 exhibited high UVB (SPF ca. 40) and antioxidant activities (free radical scavenging potency EC50 = 0.6694 and 1.700 mol compound/mol DPPH•; ferric reducing power 0.392 and 0.546, at 500 ppm and inhibited lipid peroxidation); protecting cells (%cell viability ca. 76 at 15 µM) and DNA (%DNA-integrity ca. 57 at 100 µM). Compounds 1 to 3 fulfilled some physicochemical properties to act topically on the skin.

18.
Int J Mol Sci ; 24(19)2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37833869

RESUMO

The synthesis of a new family of ethylenediaminetetraacetic acid (EDTA) core dimers and G0 dendrimers end-capped with two and four ß-cyclodextrin (ßCD) moieties was performed by click-chemistry conjugation, varying the spacers attached to the core. The structure analyses were achieved in DMSO-d6 and the self-inclusion process was studied in D2O by 1H-NMR spectroscopy for all platforms. It was demonstrated that the interaction with adamantane carboxylic acid (AdCOOH) results in a guest-induced shift of the self-inclusion effect, demonstrating the full host ability of the ßCD units in these new platforms without any influence of the spacer. The results of the quantitative size and water solubility measurements demonstrated the equivalence between the novel EDTA-ßCD platforms and the classical PAMAM-ßCD dendrimer. Finally, we determined the toxicity for all EDTA-ßCD platforms in four different cell lines: two human breast cancer cells (MCF-7 and MDA-MB-231), human cervical adenocarcinoma cancer cells (HeLa), and human lung adenocarcinoma cells (SK-LU-1). The new EDTA-ßCD carriers did not present any cytotoxicity in the tested cell lines, which showed that these new classes of platforms are promising candidates for drug delivery.


Assuntos
Dendrímeros , beta-Ciclodextrinas , Humanos , Ácido Edético/farmacologia , Dendrímeros/química , beta-Ciclodextrinas/farmacologia , beta-Ciclodextrinas/química , Sistemas de Liberação de Medicamentos , Fenômenos Químicos , Solubilidade
19.
Environ Microbiol ; 25(12): 3255-3268, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37813828

RESUMO

The guanine/cytosine (GC) content of prokaryotic genomes is species-specific, taking values from 16% to 77%. This diversity of selection for GC content remains contentious. We analyse the correlations between GC content and a range of phenotypic and genotypic data in thousands of prokaryotes. GC content integrates well with these traits into r/K selection theory when phenotypic plasticity is considered. High GC-content prokaryotes are r-strategists with cheaper descendants thanks to a lower average amino acid metabolic cost, colonize unstable environments thanks to flagella and a bacillus form and are generalists in terms of resource opportunism and their defence mechanisms. Low GC content prokaryotes are K-strategists specialized for stable environments that maintain homeostasis via a high-cost outer cell membrane and endospore formation as a response to nutrient deprivation, and attain a higher nutrient-to-biomass yield. The lower proteome cost of high GC content prokaryotes is driven by the association between GC-rich codons and cheaper amino acids in the genetic code, while the correlation between GC content and genome size may be partly due to functional diversity driven by r/K selection. In all, molecular diversity in the GC content of prokaryotes may be a consequence of ecological r/K selection.


Assuntos
Aminoácidos , Células Procarióticas , Composição de Bases , Aminoácidos/análise , Códon , Proteoma/genética
20.
Environ Microbiol ; 25(12): 3052-3063, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37658654

RESUMO

Microbes are often discussed in terms of dichotomies such as copiotrophic/oligotrophic and fast/slow-growing microbes, defined using the characterisation of microbial growth in isolated cultures. The dichotomies are usually qualitative and/or study-specific, sometimes precluding clear-cut results interpretation. We can unravel microbial dichotomies as life history strategies by combining ecology theory with Monod curves, a laboratory mathematical tool of bacterial physiology that relates the specific growth rate of a microbe with the concentration of a limiting nutrient. Fitting of Monod curves provides quantities that directly correspond to key parameters in ecological theories addressing species coexistence and diversity, such as r/K selection theory, resource competition and community structure theory and the CSR triangle of life strategies. The resulting model allows us to reconcile the copiotrophic/oligotrophic and fast/slow-growing dichotomies as different subsamples of a life history strategy triangle that also includes r/K strategists. We also used the number of known carbon sources together with community structure theory to partially explain the diversity of heterotrophic microbes observed in metagenomics experiments. In sum, we propose a theoretical framework for the study of natural microbial communities that unifies several existing proposals. Its application would require the integration of metagenomics, metametabolomics, Monod curves and carbon source data.


Assuntos
Bactérias , Microbiota , Bactérias/genética , Processos Heterotróficos , Metagenômica , Carbono
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