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1.
Nature ; 605(7909): 285-290, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35477765

RESUMO

Comprehensive assessments of species' extinction risks have documented the extinction crisis1 and underpinned strategies for reducing those risks2. Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction3. Because global assessments have been lacking, reptiles have been omitted from conservation-prioritization analyses that encompass other tetrapods4-7. Reptiles are unusually diverse in arid regions, suggesting that they may have different conservation needs6. Here we provide a comprehensive extinction-risk assessment of reptiles and show that at least 1,829 out of 10,196 species (21.1%) are threatened-confirming a previous extrapolation8 and representing 15.6 billion years of phylogenetic diversity. Reptiles are threatened by the same major factors that threaten other tetrapods-agriculture, logging, urban development and invasive species-although the threat posed by climate change remains uncertain. Reptiles inhabiting forests, where these threats are strongest, are more threatened than those in arid habitats, contrary to our prediction. Birds, mammals and amphibians are unexpectedly good surrogates for the conservation of reptiles, although threatened reptiles with the smallest ranges tend to be isolated from other threatened tetrapods. Although some reptiles-including most species of crocodiles and turtles-require urgent, targeted action to prevent extinctions, efforts to protect other tetrapods, such as habitat preservation and control of trade and invasive species, will probably also benefit many reptiles.


Assuntos
Conservação dos Recursos Naturais , Extinção Biológica , Répteis , Jacarés e Crocodilos , Anfíbios , Animais , Biodiversidade , Aves , Mamíferos , Filogenia , Répteis/classificação , Medição de Risco , Tartarugas
2.
Nature ; 603(7902): 687-692, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35062015

RESUMO

The recent emergence of B.1.1.529, the Omicron variant1,2, has raised concerns of escape from protection by vaccines and therapeutic antibodies. A key test for potential countermeasures against B.1.1.529 is their activity in preclinical rodent models of respiratory tract disease. Here, using the collaborative network of the SARS-CoV-2 Assessment of Viral Evolution (SAVE) programme of the National Institute of Allergy and Infectious Diseases (NIAID), we evaluated the ability of several B.1.1.529 isolates to cause infection and disease in immunocompetent and human ACE2 (hACE2)-expressing mice and hamsters. Despite modelling data indicating that B.1.1.529 spike can bind more avidly to mouse ACE2 (refs. 3,4), we observed less infection by B.1.1.529 in 129, C57BL/6, BALB/c and K18-hACE2 transgenic mice than by previous SARS-CoV-2 variants, with limited weight loss and lower viral burden in the upper and lower respiratory tracts. In wild-type and hACE2 transgenic hamsters, lung infection, clinical disease and pathology with B.1.1.529 were also milder than with historical isolates or other SARS-CoV-2 variants of concern. Overall, experiments from the SAVE/NIAID network with several B.1.1.529 isolates demonstrate attenuated lung disease in rodents, which parallels preliminary human clinical data.


Assuntos
COVID-19/patologia , COVID-19/virologia , Modelos Animais de Doenças , SARS-CoV-2/patogenicidade , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Cricetinae , Feminino , Humanos , Pulmão/patologia , Pulmão/virologia , Masculino , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Carga Viral
3.
FEMS Yeast Res ; 242024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38587863

RESUMO

Previously, we reported an engineered Saccharomyces cerevisiae CEN.PK113-1A derivative able to produce succinic acid (SA) from glycerol with net CO2 fixation. Apart from an engineered glycerol utilization pathway that generates NADH, the strain was equipped with the NADH-dependent reductive branch of the TCA cycle (rTCA) and a heterologous SA exporter. However, the results indicated that a significant amount of carbon still entered the CO2-releasing oxidative TCA cycle. The current study aimed to tune down the flux through the oxidative TCA cycle by targeting the mitochondrial uptake of pyruvate and cytosolic intermediates of the rTCA pathway, as well as the succinate dehydrogenase complex. Thus, we tested the effects of deletions of MPC1, MPC3, OAC1, DIC1, SFC1, and SDH1 on SA production. The highest improvement was achieved by the combined deletion of MPC3 and SDH1. The respective strain produced up to 45.5 g/L of SA, reached a maximum SA yield of 0.66 gSA/gglycerol, and accumulated the lowest amounts of byproducts when cultivated in shake-flasks. Based on the obtained data, we consider a further reduction of mitochondrial import of pyruvate and rTCA intermediates highly attractive. Moreover, the approaches presented in the current study might also be valuable for improving SA production when sugars (instead of glycerol) are the source of carbon.


Assuntos
Saccharomyces cerevisiae , Ácido Succínico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ácido Succínico/metabolismo , Glicerol/metabolismo , Dióxido de Carbono/metabolismo , NAD/metabolismo , Ácido Pirúvico/metabolismo , Membranas Mitocondriais/metabolismo , Carbono/metabolismo , Engenharia Metabólica/métodos
4.
Arch Pharm (Weinheim) ; 357(7): e2400081, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38548680

RESUMO

New pyridine-based chalcones 4a-h and pyrazolines 5a-h (N-acetyl), 6a-h (N-phenyl), and 7a-h (N-4-chlorophenyl) were synthesized and evaluated by the National Cancer Institute (NCI) against 60 different human cancer cell lines. Pyrazolines 6a, 6c-h, and 7a-h satisfied the pre-determined threshold inhibition criteria, obtaining that compounds 6c and 6f exhibited high antiproliferative activity, reaching submicromolar GI50 values from 0.38 to 0.45 µM, respectively. Moreover, compound 7g (4-CH3) exhibited the highest cytostatic activity of these series against different cancer cell lines from leukemia, nonsmall cell lung, colon, ovarian, renal, and prostate cancer, with LC50 values ranging from 5.41 to 8.35 µM, showing better cytotoxic activity than doxorubicin. Furthermore, the compounds were tested for antibacterial and antiplasmodial activities. Chalcone 4c was the most active with minimal inhibitory concentration (MIC) = 2 µg/mL against methicillin-resistant Staphylococcus aureus (MRSA), while the pyrazoline 6h showed a MIC = 8 µg/mL against Neisseria gonorrhoeae. For anti-Plasmodium falciparum activity, the chalcones display higher activity with EC50 values ranging from 10.26 to 10.94 µg/mL. Docking studies were conducted against relevant proteins from P. falciparum, exhibiting the minimum binding energy with plasmepsin II. In vivo toxicity assay in Galleria mellonella suggests that most compounds are low or nontoxic.


Assuntos
Antibacterianos , Antimaláricos , Antineoplásicos , Chalconas , Testes de Sensibilidade Microbiana , Plasmodium falciparum , Pirazóis , Piridinas , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Chalconas/farmacologia , Chalconas/síntese química , Chalconas/química , Antibacterianos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Linhagem Celular Tumoral , Relação Estrutura-Atividade , Plasmodium falciparum/efeitos dos fármacos , Pirazóis/farmacologia , Pirazóis/química , Pirazóis/síntese química , Piridinas/farmacologia , Piridinas/química , Piridinas/síntese química , Antimaláricos/farmacologia , Antimaláricos/síntese química , Antimaláricos/química , Simulação de Acoplamento Molecular , Ensaios de Seleção de Medicamentos Antitumorais , Proliferação de Células/efeitos dos fármacos , Estrutura Molecular , Animais , Relação Dose-Resposta a Droga , Neisseria gonorrhoeae/efeitos dos fármacos
5.
J Infect Dis ; 228(10): 1441-1451, 2023 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-37566913

RESUMO

BACKGROUND: Mansonellosis is an undermapped insect-transmitted disease caused by filarial nematodes that are estimated to infect hundreds of millions of people. Despite their prevalence, there are many outstanding questions regarding the general biology and health impacts of the responsible parasites. Historical reports suggest that the Colombian Amazon is endemic for mansonellosis and may serve as an ideal location to pursue these questions. METHODS: We deployed molecular and classical approaches to survey Mansonella prevalence among adults belonging to indigenous communities along the Amazon River and its tributaries near Leticia, Colombia. RESULTS: Loop-mediated isothermal amplification (LAMP) assays on whole-blood samples detected a much higher prevalence of Mansonella ozzardi infection (approximately 40%) compared to blood smear microscopy or LAMP performed using plasma, likely reflecting greater sensitivity and the ability to detect low microfilaremias and occult infections. Mansonella infection rates increased with age and were higher among men. Genomic analysis confirmed the presence of M. ozzardi that clusters closely with strains sequenced in neighboring countries. We successfully cryopreserved M. ozzardi microfilariae, advancing the prospects of rearing infective larvae in controlled settings. CONCLUSION: These data suggest an underestimation of true mansonellosis prevalence, and we expect that these methods will help facilitate the study of mansonellosis in endemic and laboratory settings.


Assuntos
Mansonelose , Parasitos , Masculino , Adulto , Animais , Humanos , Mansonella/genética , Mansonelose/epidemiologia , Mansonelose/parasitologia , Colômbia/epidemiologia , Prevalência
6.
J Am Chem Soc ; 145(30): 16517-16525, 2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37467341

RESUMO

High-throughput synthesis of solution-processable structurally variable small-molecule semiconductors is both an opportunity and a challenge. A large number of diverse molecules provide a possibility for quick material discovery and machine learning based on experimental data. However, the diversity of the molecular structure leads to the complexity of molecular properties, such as solubility, polarity, and crystallinity, which poses great challenges to solution processing and purification. Here, we first report an integrated system for the high-throughput synthesis, purification, and characterization of molecules with a large variety. Based on the principle "Like dissolves like," we combine theoretical calculations and a robotic platform to accelerate the purification of those molecules. With this platform, a material library containing 125 molecules and their optical-electronic properties was built within a timeframe of weeks. More importantly, the high repeatability of recrystallization we design is a reliable approach to further upgrading and industrial production.

7.
Curr Issues Mol Biol ; 45(8): 6903-6915, 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37623254

RESUMO

In recent years, cell culture has become an important tool not only in research laboratories, but also in diagnostic and biotechnological development laboratories. Mycoplasma contamination is present in up to 35% of cell cultures used in research and in cell therapies. This fact represents a significant problem since such contamination can cause disastrous effects on eukaryotic cells by altering their cellular parameters, which, in turn, can lead to unreliable experimental results. For this reason, it is mandatory to carry out continuous testing for the presence of Mycoplasma in cell culture and the development of appropriate methodologies for this purpose. An ideal detection methodology should be fast, sensitive, and reliable. In this study, we propose an alternative detection method based on real-time PCR in conjunction with a novel combination of primers and probes that have been improved to increase their efficiency. The new PCR method demonstrates 100% sensitivity and specificity results in the detection of common Mycoplasma species that contaminate cell cultures. Whilst 11 of 45 tested supernatants were positive for Mycoplasma (24.4%) using the new PCR method (corresponding to 5 of the 14 lines tested (35.71%)), only 10 of 45 supernatants showed positive results with the commercial Venor®GeM qEP and Plasmotest® kit. In addition, the new PCR method exhibits a high capacity to detect less-frequent Mycoplasma species, such as those related to the M. mycoides cluster. The use of an alternative Mycoplasma-detection method in cell culture labs can guarantee the detection of Mycoplasma contamination, especially in cases when dubious results are recorded.

8.
Proc Biol Sci ; 290(1990): 20221703, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36629109

RESUMO

Increasing seawater temperatures are expected to have profound consequences for reef-building corals' physiology. Understanding how demography changes in response to chronic exposure to warming will help forecast how coral communities will respond to climate change. Here, we measure growth rates of coral fragments of four common species, while exposing them to temperatures ranging from 19°C to 31°C for one month to calibrate their thermal-performance curves (TPCs). Our results show that, while there are contrasting differences between species, the shape of the TPCs was remarkably consistent among individuals of the same species. The low variation in thermal sensitivity within species may imply a reduced capacity for rapid adaptive responses to future changes in thermal regimes. Additionally, interspecific differences in thermal responses show a negative relationship between maximum growth and thermal optima, contradicting expectations derived from the classic 'warmer-is-better' hypothesis. Among species, there was a trade-off between current and future growth, whereby most species perform well under current thermal regimes but are susceptible to future increases in temperature. Increases in water temperature with climate change are likely to reduce growth rates, further hampering future coral reef recovery rates and potentially altering community composition.


Assuntos
Antozoários , Animais , Antozoários/fisiologia , Recifes de Corais , Água do Mar , Temperatura , Mudança Climática
9.
New Phytol ; 240(2): 597-612, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37548040

RESUMO

Here, we report the characterization of a plant RNA methyltransferase, orthologous to yeast trimethylguanosine synthase1 (Tgs1p) and whose downregulation was associated with apomixis in Paspalum grasses. Using phylogenetic analyses and yeast complementation, we determined that land plant genomes all encode a conserved, specific TGS1 protein. Next, we studied the role of TGS1 in female reproduction using reporter lines and loss-of-function mutants in Arabidopsis thaliana. pAtTGS1:AtTGS1 reporters showed a dynamic expression pattern. They were highly active in the placenta and ovule primordia at emergence but, subsequently, showed weak signals in the nucellus. Although expressed throughout gametophyte development, activity became restricted to the female gamete and was also detected after fertilization during embryogenesis. TGS1 depletion altered the specification of the precursor cells that give rise to the female gametophytic generation and to the sporophyte, resulting in the formation of a functional aposporous-like lineage. Our results indicate that TGS1 participates in the mechanisms restricting cell fate acquisition to a single cell at critical transitions throughout the female reproductive lineage and, thus, expand our current knowledge of the mechanisms governing female reproductive fate in plants.


Assuntos
Arabidopsis , Arabidopsis/metabolismo , Saccharomyces cerevisiae , Filogenia , Mutação/genética , Óvulo Vegetal/metabolismo , Células Germinativas , Regulação da Expressão Gênica de Plantas
10.
J Exp Bot ; 74(10): 3074-3093, 2023 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-36812152

RESUMO

Pseudogamous apomixis in Paspalum simplex generates seeds with embryos genetically identical to the mother plant and endosperms deviating from the canonical 2(maternal):1(paternal) parental genome contribution into a maternal excess 4m:1p genome ratio. In P. simplex, the gene homologous to that coding for subunit 3 of the ORIGIN OF RECOGNITION COMPLEX (PsORC3) exists in three isogenic forms: PsORC3a is apomixis specific and constitutively expressed in developing endosperm whereas PsORCb and PsORCc are up-regulated in sexual endosperms and silenced in apomictic ones. This raises the question of how the different arrangement and expression profiles of these three ORC3 isogenes are linked to seed development in interploidy crosses generating maternal excess endosperms. We demonstrate that down-regulation of PsORC3b in sexual tetraploid plants is sufficient to restore seed fertility in interploidy 4n×2n crosses and, in turn, its expression level at the transition from proliferating to endoreduplication endosperm developmental stages dictates the fate of these seeds. Furthermore, we show that only when being maternally inherited can PsORC3c up-regulate PsORC3b. Our findings lay the basis for an innovative route-based on ORC3 manipulation-to introgress the apomictic trait into sexual crops and overcome the fertilization barriers in interploidy crosses.


Assuntos
Endosperma , Paspalum , Endosperma/genética , Paspalum/genética , Sementes/genética
11.
Soft Matter ; 19(32): 6066-6073, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37318304

RESUMO

Chiral liquid crystals (ChLCs) exhibit an inherent twist that originates at the molecular scale and can extend over multiple length scales when unconstrained. Under confinement, the twist is thwarted, leading to formation of defects in the molecular order that offer distinct optical responses and opportunities for colloidal driven assembly. Past studies have explored spheroidal confinement down to the nanoscopic regime, where curved boundaries produce surface defects to accommodate topological constraints and restrict the propagation of cuboidal defect networks. Similarly, strict confinement in channels and shells has been shown to give rise to escaped configurations and skyrmions. However, little is known about the role of extrinsic curvature in the development of cholesteric textures and Blue Phases (BP). In this paper, we examine the palette of morphologies that arises when ChLCs are confined in toroidal and cylindrical cavities. The equilibrium morphologies are obtained following an annealing strategy of a Landau-de Gennes free energy functional. Three dimensionless groups are identified to build phase diagrams: the natural twist, the ratio of elastic energies, and the circumscription of a BP cell. Curvature is shown to introduce helical features that are first observed as a Double Twist, and progress to Chiral Ribbons and, ultimately, Helical BP and BP. Chiral ribbons are examined as useful candidates for driven assembly given their tunability and robustness.

12.
Plant Dis ; 2023 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-36825318

RESUMO

Tomato (Solanum lycopersicum L.) is one of the most important crops in Mexico due to its economic and nutritional value. Among the main diseases in tomato production is Fusarium wilt, which can cause 60% production losses (Ascencio et al, 2008). Mixed infections of Fusarium species or other fungi genera, would increase disease severity. During April to May of 2021, tomato plants with more than 60 days old, were collected from the main production areas of Aguascalientes (22°03'46.5"N 102°05'17.4"W and 22°04'53.64"N 101°58'55.81"W) and Zacatecas (23°05'59.2"N 102°41'07.3"W and 22°16'52.1"N 102°00'11.8"W) Mexico states. Plants showed main root rot, vascular bundles necrosis with corky appearance, stem crown rot, and ascending yellowing. The main root and stem crown were cut in 0.25 cm2 pieces and disinfested in 2% NaClO for one minute, rinsed with distilled water two times, placed on acidified potato dextrose agar (PDA) medium, and incubated at 25 ± 2°C for 7 days. Characteristic Fusarium growths were purified by hyphal tip on PDA, subsequently pure strains were obtained by single-spore isolation method. Several fungi colonies were obtained, but we focused on the colonies that showed abundant aerial mycelium of white color and irregular growth, which turned yellowish to golden and brown color as it ages. Carnation leaf agar (CLA) medium were used for conidia and sporodochium development. Chains of terminal, intercalary and agglomerated chlamydospores with thick, rough brown walls of 18.9 (7.46) µm in diameter (n=120) were observed in the mycelium. Macroconidia with 5 to 7 septa were 30 to 75 (28.32) µm in long and 1.2 to 4.8 (3.2) µm in wide (n=72). Basal cell developed in foot-shape, apical cell was elongated and slightly curved, and some macroconidia had swollen midd-cell. Sporodochium was orange to brown in color and microconidia were absent (Figure 1). Two representative strains from each state, LCA-3.1 and EMA-1 from Aguascalientes and ECZ-4 and LRZ-6 from Zacatecas, were selected for DNA amplification of ITS, TEF-1α and RPB2 regions, with universal primers ITS1/ITS4, EF1/EF2 and 2-5F2/7cR (White et al.1990; O'Donnell et al. 1998, 2013). PCR products were sequenced by Psomagen, Inc. (USA). The sequences obtained showed 100% of similarity among themselves and within species of the Fusarium incarnatum-equiseti species complex (FIESC) with nucleotide NCBI accessions NR_121457 (Type material) for ITS and MW362069 for TEF-1α; and 99.28% with MN170399 for RPB2 in FUSARIOID-ID database. According to morphological (Leslie and Summerell, 2006) and molecular characteristics, isolates were identified as Fusarium equiseti (FIESC 14). The LCA-3.1 sequences were selected to be deposited in GenBank with accession numbers OM812801 (ITS), OM937108 (TEF-1α) and ON653596 (RPB2). Pathogenicity tests were performed twice, under greenhouse conditions in tomato seedlings of cv. Rio Grande. Five tomato seedlings were inoculated by root immersion method (Lopez et al, 2018) in a 1x106 spores/mL solution for 8 min, and transplanted to 1L pots with sterile peat. Five controls plants were immersed in sterile water. At 14 days after inoculation, a general plant decline and slower growth compared to the control plants were observed. Subsequently, plants showed root rot, vascular necrosis, and a brown ring in stem crown. Controls were symptomless. The fungi were re-isolated from symptomatic plants and were morphologically similar to the inoculated strains. Patel et al. (2017) described the pathogenic and toxic effects of F. equiseti on tomato, causing low seed germination, and low root and shoot growth. This is the first report of F. equiseti causing root and stem rot in tomato plants in Mexico.

13.
Int J Mol Sci ; 24(5)2023 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-36902401

RESUMO

The composition and impact of fecal-microbe-derived extracellular vesicles (EVs) present in different diseases has not been analyzed. We determined the metagenomic profiling of feces and fecal-microbe-derived EVs from healthy subjects and patients with different diseases (diarrhea, morbid obesity and Crohn's disease (CD)) and the effect of these fecal EVs on the cellular permeability of Caco-2 cells. The control group presented higher proportions of Pseudomonas and Rikenellaceae_RC9_gut_group and lower proportions of Phascolarctobacterium, Veillonella and Veillonellaceae_ge in EVs when compared with the feces from which these EVs were isolated. In contrast, there were significant differences in 20 genera between the feces and EV compositions in the disease groups. Bacteroidales and Pseudomonas were increased, and Faecalibacterium, Ruminococcus, Clostridium and Subdoligranum were decreased in EVs from control patients compared with the other three groups of patients. Tyzzerella, Verrucomicrobiaceae, Candidatus_Paracaedibacter and Akkermansia were increased in EVs from the CD group compared with the morbid obesity and diarrhea groups. Fecal EVs from the morbid obesity, CD and, mainly, diarrhea induced a significant increase in the permeability of Caco-2 cells. In conclusion, the metagenomic composition of fecal-microbe-derived EVs changes depending on the disease of the patients. The modification of the permeability of Caco-2 cells produced by fecal EVs depends on the disease of the patients.


Assuntos
Doença de Crohn , Vesículas Extracelulares , Obesidade Mórbida , Humanos , Células CACO-2 , Doença de Crohn/microbiologia , Fezes/microbiologia , Diarreia
14.
Chemistry ; 28(59): e202201450, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36047501

RESUMO

We are reporting the synthesis, single-crystal X-ray structure characterization, and magnetic property investigations of the pivalate butterfly {CrIII 2 LnIII 2 } complexes with Ln= Gd and Dy and the isostructural Y(III) sample. We found an anti-ferromagnetic Cr(III)-Ln(III) exchange interaction, which, as previously observed in related Cr(III)/Ln(III) systems, plays a key role in suppressing quantum tunnelling of magnetization and enhances the SMM performance in the Dy(III) complex. In fact, a pure Orbach relaxation mechanism, with absence of QT regime, is observed with a thermal barrier of 50 cm-1 , leading to magnetization hysteresis opening, measured with a commercial magnetometer, up to 3.6 K with a coercive field of 2.9 T. Analysis of SMM behaviour in literature-known butterfly {CrIII 2 DyIII 2 } complexes, reveals the existence of a magneto-structural correlation between Ueff , the thermal barrier size, and the mean Cr-Dy bond distances. Moreover, a clear correlation is found for the thermal barrier magnitude and the maximum temperature hysteresis opening and coercive field.

15.
Microb Cell Fact ; 21(1): 102, 2022 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-35643577

RESUMO

BACKGROUND: The microbial production of succinic acid (SA) from renewable carbon sources via the reverse TCA (rTCA) pathway is a process potentially accompanied by net-fixation of carbon dioxide (CO2). Among reduced carbon sources, glycerol is particularly attractive since it allows a nearly twofold higher CO2-fixation yield compared to sugars. Recently, we described an engineered Saccharomyces cerevisiae strain which allowed SA production in synthetic glycerol medium with a maximum yield of 0.23 Cmol Cmol-1. The results of that previous study suggested that the glyoxylate cycle considerably contributed to SA accumulation in the respective strain. The current study aimed at improving the flux into the rTCA pathway accompanied by a higher CO2-fixation and SA yield. RESULTS: By changing the design of the expression cassettes for the rTCA pathway, overexpressing PYC2, and adding CaCO3 to the batch fermentations, an SA yield on glycerol of 0.63 Cmol Cmol-1 was achieved (i.e. 47.1% of the theoretical maximum). The modifications in this 2nd-generation SA producer improved the maximum biomass-specific glycerol consumption rate by a factor of nearly four compared to the isogenic baseline strain solely equipped with the dihydroxyacetone (DHA) pathway for glycerol catabolism. The data also suggest that the glyoxylate cycle did not contribute to the SA production in the new strain. Cultivation conditions which directly or indirectly increased the concentration of bicarbonate, led to an accumulation of malate in addition to the predominant product SA (ca. 0.1 Cmol Cmol-1 at the time point when SA yield was highest). Off-gas analysis in controlled bioreactors with CO2-enriched gas-phase indicated that CO2 was fixed during the SA production phase. CONCLUSIONS: The data strongly suggest that a major part of dicarboxylic acids in our 2nd-generation SA-producer was formed via the rTCA pathway enabling a net fixation of CO2. The greatly increased capacity of the rTCA pathway obviously allowed successful competition with other pathways for the common precursor pyruvate. The overexpression of PYC2 and the increased availability of bicarbonate, the co-substrate for the PYC reaction, further strengthened this capacity. The achievements are encouraging to invest in future efforts establishing a process for SA production from (crude) glycerol and CO2.


Assuntos
Saccharomyces cerevisiae , Ácido Succínico , Bicarbonatos/metabolismo , Dióxido de Carbono/metabolismo , Meios de Cultura/metabolismo , Glicerol/metabolismo , Glioxilatos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ácido Succínico/metabolismo
16.
J Chem Phys ; 157(20): 204104, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36456228

RESUMO

Understanding electrostatic interactions among dielectric bodies in the atmosphere and aerosols is central to controlling their aggregation. Polarization effects, which are frequently ignored, are crucial to determine interactions when geometrical anisotropies are present due to surface-induced charge segregation. Here, we adopt a direct integral formulation that accounts for the problem of charged dielectric bodies immersed in a continuum media to explore particle aggregation via geometrical tuning. We show that by breaking the structural symmetry and modifying the close-contact surface between particles of equal charge, it is possible to obtain attractive regimes at short and long distances. We evaluate the electrostatic forces and energy of a set of dimers and trimers composed of spheres, oblates, and prolates in a vacuum, where no counter-ions are present, to construct a phase diagram with the conditions required to form stable aggregates as a function of the geometrical anisotropy. We found that it is possible to direct the aggregation (or dispersion) of two and three positive dielectric particles by adjusting their geometry and controlling the contact surface among them. Our results give insight into a way to control the aggregation of dielectric systems and offer a prospect for directing the assembly of complex particle structures.

17.
J Biomech Eng ; 144(5)2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34773458

RESUMO

The maximum stresses on a femoral stem must be known for selecting the right size and shape of the shaft cross-sectional area for reducing the stress shielding effect generated after the total hip arthroplasty (THA) surgical procedure. The methodology proposed in this study provides the tools to the designers of femoral stems and orthopedic surgeons to select the adequate femoral stem cross section, decreasing the stiffness of the stem, thus reducing the stress shielding effect in the patient bones. The first contribution is the theoretical development of the maximum static stress calculation for 12 different femoral stem models with the beam theory, followed by the comparison with the static finite element analysis (FEA) simulations and finally the experimental corroboration of one femoral stem model measuring the strain with linear strain gages and transform it to stresses, the three different approaches provide comparable results, with a maximum average error of less than 8.5%. The second contribution is the formulation of a new selection methodology based on maximum stresses in the femoral stem and the cross section area for decreasing the stress shielding effect, optimizing the area needed for withstand the loads and decreasing the overall stiffens of the stem.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Artroplastia de Quadril/métodos , Fêmur/cirurgia , Análise de Elementos Finitos , Humanos , Desenho de Prótese , Estresse Mecânico
18.
Plant Dis ; 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35171642

RESUMO

Garlic (Allium sativum) is an important crop worldwide and it is widely grown and used in different industries to manufacture food, pharmaceutical, and insecticidal products. (Shang et al., 2019, Velsankar et al., 2020). According to what was reported by SIAP in 2020, more than 87 ha of the crop were lost in Mexico due to various problems, including the diseases that attack this crop such as basal rot, white rot and root rot, among others. During the 2019 fall/winter season, garlic plants of Perla and Piedra Blanca cultivars were collected from Aguascalientes and Zacatecas states in San Antonio Tepezala, Rincon de Romos, and Calera municipalities. The commercial fields encompassed 10 ha with 20% disease incidence and 35% severity, approximately. The sampling focused on diseased plants with symptoms of root rot, foliar wilt, stunting, and small bulbs. The roots of 25 plants were cleaned, and portions of the diseased tissue were cut and disinfected in sodium hypochlorite at 1% for three minutes. They were rinsed twice with sterile water and dried with paper towels. The plant tissue was plated onto potato dextrose agar (PDA) and incubated at 25°C in the dark for 72 hours. Pure cultures were obtained after observing mycelial growth using monosporal culture. We obtained 16 isolates including three identified as Fusarium oxysporum, one as Fusarium solani and another 12 as Clonostachys rosea. The latter isolates were white at the beginning before turning yellow. The mycelia had a felt-like cotton texture. The conidia formed verticillate and penicillate conidiophores. The primary conidia were abundant, hyaline, smooth, and sub-globous. They were 5.1-7.7 X 8.3-8.9 µm (n=50) long and 2.0-2.9 X 3.2-3.5 µm wide (n=50). The conidiophore stipe length ranged from 70 to 180 µm, and the base width was 3.3-5.4 µm. Secondary conidiophores were penicillate and stiped with a length of 58 to 106 µm; the base measured 3.3-6.1µm. The secondary conidia measured 4.1-5 X 5.3-5.6 µm long and 2-2.3 X 2.6-2.9 µm wide (n=50) (Sun et al., 2020). The identity of six isolates was molecularly confirmed by DNA extraction and PCR reactions using ITS1/ITS4 primers and gene TEF 1α EF1-728F/TEF 1α EF1-986R. The resulting products were sequenced and compared with the National Center for Biotechnology Information (NCBI) database using BLAST. The results showed Clonostachys rosea at 99.56 and 100% with access numbers MN548399 and KX185000. The sequences were deposited at Genbank database under access number OK263088 and OL700031. Pathogenicity tests were carried out with the following procedure. A conidial suspension of five isolates (5×105 conidia/ml) in sterilized water was prepared from 1-week-old colonies. The garlic cloves were planted after being disinfected with sodium hypochlorite at 1% in sterilized soil. When the healthy garlic plants were 30 days old, we inoculated a spore suspension in soil through irrigation, to 10 plants. Likewise,10 control plants were inoculated with sterile distilled water. After 25 days, the plants were wilted and had dry leaves; their root system showed light-brown lesions and rot. These plants were stunted versus the control healthy plants. The inoculated strain was recovered and was morphologically and molecularly identified as C. rosea, thus confirming its pathogenicity towards garlic. There are reports of C. rosea causing root rot to Fabaceae crops such as Glycine max L. and Vicia faba L., (Bienapfl et al., 2012; Afshari and Hemmati, 2017) in addition to affecting orchid crops (Gastrodia elata) in Korea (Lee et al., 2020). This is the first report of C. rosea causing root rot on garlic (Allium Sativum) in Mexico, thus presenting a potential risk to this crop.

19.
Gastroenterol Hepatol ; 45(6): 432-439, 2022.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-34129902

RESUMO

INTRODUCTION: Zenker's diverticulum (ZD) is a protrusion of the hypopharyngeal mucosa with a prevalence of 2/100,000 inhabitants. The symptoms of the patients determine the need for treatment, which can be surgical or endoscopic. The latter, known as endoscopic septotomy or diverticulotomy (ED), this involves dissecting the diverticular septum, which can be performed with different dissection devices. AIM: The aim of our study was to evaluate the efficacy and safety of ED with Stag-Beetle-Knife™ device, as well as to conduct a literature review to assess the position of the technique in the current scientific panorama. MATERIAL AND METHODS: Descriptive retrospective study that includes patients who underwent ED with SB-Knife™ between June 2017 and February 2020. Literature review of the available evidence between January 2013 and April 2020 of ED with SB-Knife™ technique and its variants. RESULTS: Twelve patients (66% male) with a median age of 70.5 years were collected. The median size of diverticular was 32.5mm and complete remission was observed in 75% of the cases. Fourteen interventions were performed with a technical success of 92.8. There were no serious complications. A literature review was carried out, finding 13 papers, of which 8 were finally included (6 retrospective studies, a series of cases and a clinical case). CONCLUSION: Based on our experience and the reviewed literature, we consider ED with SB-Knife™ is a safe, effective and reproducible technique, and may be a better alternative to surgery in patients with ZD.


Assuntos
Besouros , Divertículo de Zenker , Animais , Endoscopia , Esofagoscopia/métodos , Feminino , Humanos , Masculino , Estudos Observacionais como Assunto , Estudos Retrospectivos , Resultado do Tratamento , Divertículo de Zenker/cirurgia
20.
BMC Genomics ; 22(1): 185, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33726667

RESUMO

BACKGROUND: Apomixis, an asexual mode of plant reproduction, is a genetically heritable trait evolutionarily related to sexuality, which enables the fixation of heterozygous genetic combinations through the development of maternal seeds. Recently, reference floral transcriptomes were generated from sexual and apomictic biotypes of Paspalum notatum, one of the most well-known plant models for the study of apomixis. However, the transcriptome dynamics, the occurrence of apomixis vs. sexual expression heterochronicity across consecutive developmental steps and the orientation of transcription (sense/antisense) remain unexplored. RESULTS: We produced 24 Illumina TruSeq®/ Hiseq 1500 sense/antisense floral transcriptome libraries covering four developmental stages (premeiosis, meiosis, postmeiosis, and anthesis) in biological triplicates, from an obligate apomictic and a full sexual genotype. De novo assemblies with Trinity yielded 103,699 and 100,114 transcripts for the apomictic and sexual samples respectively. A global comparative analysis involving reads from all developmental stages revealed 19,352 differentially expressed sense transcripts, of which 13,205 (68%) and 6147 (32%) were up- and down-regulated in apomictic samples with respect to the sexual ones. Interestingly, 100 differentially expressed antisense transcripts were detected, 55 (55%) of them up- and 45 (45%) down-regulated in apomictic libraries. A stage-by-stage comparative analysis showed a higher number of differentially expressed candidates due to heterochronicity discrimination: the highest number of differential sense transcripts was detected at premeiosis (23,651), followed by meiosis (22,830), postmeiosis (19,100), and anthesis (17,962), while the highest number of differential antisense transcripts were detected at anthesis (495), followed by postmeiosis (164), meiosis (120) and premeiosis (115). Members of the AP2, ARF, MYB and WRKY transcription factor families, as well as the auxin, jasmonate and cytokinin plant hormone families appeared broadly deregulated. Moreover, the chronological expression profile of several well-characterized apomixis controllers was examined in detail. CONCLUSIONS: This work provides a quantitative sense/antisense gene expression catalogue covering several subsequent reproductive developmental stages from premeiosis to anthesis for apomictic and sexual P. notatum, with potential to reveal heterochronic expression between reproductive types and discover sense/antisense mediated regulation. We detected a contrasting transcriptional and hormonal control in apomixis and sexuality as well as specific sense/antisense modulation occurring at the onset of parthenogenesis.


Assuntos
Apomixia , Paspalum , Apomixia/genética , Regulação da Expressão Gênica de Plantas , Paspalum/genética , Proteínas de Plantas/genética , RNA Antissenso/genética , Sementes/metabolismo , Transcriptoma
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