Lactic acid bacteria (LAB) are capable of converting carbohydrate substrates into organic acids (mainly lactic acid) and producing a wide range of metabolites. Due to their interesting beneficial ...properties, LAB are widely used as starter cultures, as probiotics, and as microbial cell factories. Exploring LAB present in unknown niches may lead to the isolation of unique species or strains with relevant technological properties. Autochthonous rather than allochthonous starter cultures are preferred in the current industry of fermented food products, due to better adaptation and performance of autochthonous strains to the matrix they originate from. In this work, the lactic microbiota of eight different wild tropical types of fruits and four types of flowers were studied. The ability of the isolated strains to produce metabolites of interest to the food industry was evaluated. The presence of 21 species belonging to the genera
, and
was evidenced by using culture-dependent techniques. The isolated LAB corresponded to 95 genotypically differentiated strains by applying rep-PCR and sequencing of the 16S rRNA gene; subsequently, representative strains of the different isolated species were studied for technological properties, such as fast growth rate and acidifying capacity; pectinolytic and cinnamoyl esterase activities, and absence of biogenic amine biosynthesis. Additionally, the strains' capacity to produce ethyl esters as well as mannitol was evaluated. The isolated fruit- and flower-origin LAB displayed functional properties that validate their potential use in the manufacture of fermented fruit-based products setting the background for the design of novel functional foods.
Mannitol is a natural low-calorie sugar alcohol produced by certain (micro)organisms applicable in foods for diabetics due to its zero glycemic index. In this work, we evaluated mannitol production ...and yield by the fruit origin strain
Fructobacillus tropaeoli
CRL 2034 using response surface methodology with central composite design (CCD) as optimization strategy. The effect of the total saccharide (glucose + fructose, 1:2) content (TSC) in the medium (75, 100, 150, 200, and 225 g/l) and stirring (S; 50, 100, 200, 300 and 350 rpm) on mannitol production and yield by this strain was evaluated by using a 2
2
full-factorial CCD with 4 axial points (
α
= 1.5) and four replications of the center point, leading to 12 random experimental runs. Fermentations were carried out at 30 °C and pH 5.0 for 24 h. Minitab-15 software was used for experimental design and data analyses. The multiple response prediction analysis established 165 g/l of TSC and 200 rpm of S as optimal culture conditions to reach 85.03 g/l 95% CI (78.68, 91.39) of mannitol and a yield of 82.02% 95% CI (71.98, 92.06). Finally, a validation experiment was conducted at the predicted optimum levels. The results obtained were 81.91 g/l of mannitol with a yield of 77.47% in outstanding agreement with the expected values. The mannitol 2-dehydrogenase enzyme activity was determined with 4.6–4.9 U/mg as the highest value found. To conclude,
F. tropaeoli
CRL 2034 produced high amounts of high-quality mannitol from fructose, being an excellent candidate for this polyol production.
The Fructobacillus genus is a group of obligately fructophilic lactic acid bacteria (FLAB) that requires the use of fructose or another electron acceptor for their growth. In this work, we performed ...a comparative genomic analysis within the genus Fructobacillus by using 24 available genomes to evaluate genomic and metabolic differences among these organisms. In the genome of these strains, which varies between 1.15- and 1.75-Mbp, nineteen intact prophage regions, and seven complete CRISPR-Cas type II systems were found. Phylogenetic analyses located the studied genomes in two different clades. A pangenome analysis and a functional classification of their genes revealed that genomes of the first clade presented fewer genes involved in the synthesis of amino acids and other nitrogen compounds. Moreover, the presence of genes strictly related to the use of fructose and electron acceptors was variable within the genus, although these variations were not always related to the phylogeny.
We report the draft genome sequence of
Fructobacillus tropaeoli
CRL 2034, a strain isolated from ripe fig in Tucumán province, Argentina. The interest in studying the genome of this fructophilic ...lactic acid bacterium strain was motivated by its ability to produce high levels of mannitol from fructose. This polyol has multiple industrial applications; however, it is mainly used as low calorie sugar in the food industry. The assembled genome of this strain consists of a 1.66-Mbp circular chromosome with 1465 coding sequences and a G+C content of 44.6%. The analysis of this genome supports the one step reaction of fructose reduction to mannitol by the mannitol 2-dehydrogenase enzyme, which together with a fructose permease, were identified as involved in mannitol synthesis. In addition, a phylogenetic analysis was performed including other
Leuconostocaceae
members to which the
Fructobacillus
genus belongs to; according to the 16S rRNA gene sequences, the strain CRL 2034 was located in the
Fructobacillus
clade. The present genome sequence could be useful to further elucidate regulatory processes of mannitol and other bioactive metabolites and to highlight the biotechnological potential of this fruit-origin
Fructobacillus
strain.
The Fructobacillus genus is a group of obligately fructophilic lactic acid bacteria (FLAB) that requires the use of fructose or another electron acceptor for their growth. In this work, we performed ...a comparative genomic analysis within the genus Fructobacillus by using 24 available genomes to evaluate genomic and metabolic differences among these organisms. In the genome of these strains, which varies between 1.15- and 1.75-Mbp, nineteen intact prophage regions, and seven complete CRISPR-Cas type II systems were found. Phylogenetic analyses located the studied genomes in two different clades. A pangenome analysis and a functional classification of their genes revealed that genomes of the first clade presented fewer genes involved in the synthesis of amino acids and other nitrogen compounds. Moreover, the presence of genes strictly related to the use of fructose and electron acceptors was variable within the genus, although these variations were not always related to the phylogeny.
Patients with coronavirus disaese 2019 (COVID-19) can develop a cytokine release syndrome that eventually leads to acute respiratory distress syndrome requiring invasive mechanical ventilation (IMV). ...Because IL-6 is a relevant cytokine in acute respiratory distress syndrome, the blockade of its receptor with tocilizumab (TCZ) could reduce mortality and/or morbidity in severe COVID-19.
We sought to determine whether baseline IL-6 serum levels can predict the need for IMV and the response to TCZ.
A retrospective observational study was performed in hospitalized patients diagnosed with COVID-19. Clinical information and laboratory findings, including IL-6 levels, were collected approximately 3 and 9 days after admission to be matched with preadministration and postadministration of TCZ. Multivariable logistic and linear regressions and survival analysis were performed depending on outcomes: need for IMV, evolution of arterial oxygen tension/fraction of inspired oxygen ratio, or mortality.
One hundred forty-six patients were studied, predominantly males (66%); median age was 63 years. Forty-four patients (30%) required IMV, and 58 patients (40%) received treatment with TCZ. IL-6 levels greater than 30 pg/mL was the best predictor for IMV (odds ratio, 7.1; P < .001). Early administration of TCZ was associated with improvement in oxygenation (arterial oxygen tension/fraction of inspired oxygen ratio) in patients with high IL-6 (P = .048). Patients with high IL-6 not treated with TCZ showed high mortality (hazard ratio, 4.6; P = .003), as well as those with low IL-6 treated with TCZ (hazard ratio, 3.6; P = .016). No relevant serious adverse events were observed in TCZ-treated patients.
Baseline IL-6 greater than 30 pg/mL predicts IMV requirement in patients with COVID-19 and contributes to establish an adequate indication for TCZ administration.
A thrombin-like enzyme, pictobin, was purified from Bothrops pictus snake venom. It is a 41-kDa monomeric glycoprotein as showed by mass spectrometry and contains approx. 45% carbohydrate by mass ...which could be removed with N-glycosidase. Pictobin coagulates plasma and fibrinogen, releasing fibrinopeptide A and induces the formation of a friable/porous fibrin network as visualized by SEM. The enzyme promoted platelet aggregation in human PRP and defibrination in mouse model and showed catalytic activity on chromogenic substrates S-2266, S-2366, S-2160 and S-2238. Pictobin interacts with the plasma inhibitor α2-macroglobulin, which blocks its interaction with fibrinogen but not with the small substrate BApNA. Heparin does not affect its enzymatic activity. Pictobin cross reacted with polyvalent bothropic antivenom, and its deglycosylated form reduced its catalytic action and antivenom reaction. In breast and lung cancer cells, pictobin inhibits the fibronectin-stimulated migration. Moreover, it produces strong NADH oxidation, mitochondrial depolarization, ATP decrease and fragmentation of mitochondrial network. These results suggest by first time that a snake venom serinprotease produces mitochondrial dysfunction by affecting mitochondrial dynamics and bioenergetics. Structural model of pictobin reveals a conserved chymotrypsin fold β/β hydrolase. These data indicate that pictobin has therapeutic potential in the treatment of cardiovascular disorders and metastatic disease.
•Pictobin is a highly glycosilated fibrinogen-clotting enzyme that target fibrinogen α-chains.•Pictobin induces defibrination in in vivo models and interact with the endogenous inhibitor α2-Macroglobulin,•The N-linked glycans have relevant role in enzymatic activity and cross-reactivity with therapeutic Bothrops antivenom (αBS).•We report for first time that a SV-TLE that produces mitochondrial dysfunction in tumoral cells.•Pictobin promotes NADH oxidation, mitochondrial depolarization, ATP decrease and fragmentation of mitochondrial network.
Background
Interleukin 6 (IL6) levels and SARS-CoV-2 viremia have been correlated with COVID-19 severity. The association over time between them has not been assessed in a prospective cohort. Our aim ...was to evaluate the relationship between SARS-CoV-2 viremia and time evolution of IL6 levels in a COVID-19 prospective cohort.
Methods
Secondary analysis from a prospective cohort including COVID-19 hospitalized patients from Hospital Universitario La Princesa between November 2020 and January 2021. Serial plasma samples were collected from admission until discharge. Viral load was quantified by Real-Time Polymerase Chain Reaction and IL6 levels with an enzyme immunoassay. To represent the evolution over time of both variables we used the graphic command
twoway
of Stata.
Results
A total of 57 patients were recruited, with median age of 63 years (IQR 53–81), 61.4% male and 68.4% Caucasian. The peak of viremia appeared shortly after symptom onset in patients with persistent viremia (more than 1 sample with > 1.3 log10 copies/ml) and also in those with at least one IL6 > 30 pg/ml, followed by a progressive increase in IL6 around 10 days later. Persistent viremia in the first week of hospitalization was associated with higher levels of IL6. Both IL6 and SARS-CoV-2 viral load were higher in males, with a quicker increase with age.
Conclusion
In those patients with worse outcomes, an early peak of SARS-CoV-2 viral load precedes an increase in IL6 levels. Monitoring SARS-CoV-2 viral load during the first week after symptom onset may be helpful to predict disease severity in COVID-19 patients.
Analysis of the facial biotype can provide useful information for orthodontic diagnosis and can determine the type of growth of a patient to guide orthodontic treatment. The objective of this study ...was to determine the concordance of the facial biotype according to Bjork-Jarabak cephalometric analysis and photographic analysis of the angle of facial opening in Peruvian individuals.
This retrospective study included 244 cephalometric radiographs and frontal photographs of the same patients obtained from a database. The facial biotype (mesofacial, brachyfacial, or dolichofacial) was determined with the Björk-Jarabak polygon (cephalometric) and the angle of facial opening (photographic). Two trained investigators performed all the measurements. The concordance of the facial diagnosis was determined using correlations of the interclass coefficient and the kappa test.
<0.05.
In cases with a mesofacial biotype, both analyses coincided in 60 individuals (68.2%), while in those diagnosed with a dolichofacial biotype, the analyses only coincided in 17 individuals (10.4%). There was no concordance between the two methods regarding the brachyfacial biotype since according to the angle of facial opening none of the individuals presented a brachyfacial biotype (kappa weighted test= 0.020,
=0.586).
Cephalometric and photographic analyses should be complementary and one should not substitute the other. Attention should be focused on dolichofacial and brachyfacial biotypes, which showed less concordance between evaluations. So, more studies are needed to follow this line of research.
Facial biotype, cephalometry, photography, facial type, radiography.
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