Cinética y estructura microbiana de las bacterias del ciclo del nitrógeno de la rizosfera de un humedal natural contaminado con cromo

En el manuscrito se describe la estructura y composición microbiana de un lodo de un humedal natural y sus conductas cinéticas de la nitrificación, desnitrificación y anammox, en presencia y ausencia de cromoWetlands have been considered a feasible technology for wastewater treatment in the last decades; however, information on the kinetics and microbial structure of nitrogen cycle bacteria involved on the rhizosphere activity of natural wetlands polluted with chromium is still scarce. The goal was to evaluate the kinetic behavior of nitrification, denitrification, and ANAMMOX on rhizosphere sludge, with and without chromium, through batch cultures, as well as the microbial structure using Next Generation Sequencing (NGS). The microbial sludge was able to nitrify (3.8 ± 0.2 mg NO3--N/gVSS-h) and carry out the ANAMMOX (0.67 ± 0.05 mg NH4+-N/gVSS-h), however, denitrifying activity was not observed. Chromium inhibited the nitrifying process, and the IC50 obtained for the nitrifying activity was of 7.9 mg CrVI/L. ANAMMOX activity was stopped in the presence of chromium, even to the lowest chromium concentration tested. Recovery cultures showed that ANAMMOX bacteria suffered some damage by chromium presence since they required more than 5 days to recover the activity. Microbial results indicated that Xanthomonadaceae (17.17%), Ignavibacteriaceae (16.52%), Trueperaceae (10.66%) and Chitinophagaceae (10.06%) dominated in the microbial sludge, whereas Nitrosomonas and Planctomycetaceae were in lesser proportion. This research improves the understanding of bacteria behavior on natural wetlands polluted with metals

Establishment of cell suspension cultures of prosopis laevigata (humb. & bonpl. ex willd) m.c. johnst to determine the effect of zinc on the uptake and accumulation of lead

In vitro studies indicate that Prosopis laevigata can be considered a potential hyperaccumulator of lead. Likewise, lead uptake has been related to protein transporters for zinc. In this work presents a protocol for the establishment of cell suspension culture to determine the effect of zinc on the uptake and accumulation of lead. A bioassay with Pb2+/Zn2+ (0.0, 0.5, and 1.0 mM) was carried out on cell suspension cultures derived from callus induced in half-strength Murashige and Skoog (MS) medium added with 6.8 pM 2,4-dichlorophenoxyacetic acid (2,4-D) with 4.5 pM kinetin (KIN). Cells showed significant tolerance to growth (GR>60%) at all concentrations and combinations of Pb and Zn (0.0, 0.5 and 1.0 mM). When the Pb with or without Zn were added to the culture medium, the cells showed the highest accumulation efficiency for non-essential (lead) metal over essential (zinc) metal (BF values for Pb » BF values for Zn; 2-33 times). Scanning electron micrographs evidenced the accumulation of Pb in the cells walls. These results provide insights about the tolerance and accumulation mechanisms of Pb occurring in P. laevigata

Supercritical extraction of lyophilized strawberry anthocyanins with pulsed electric fields pretreatment

Anthocyanins from LSB and with a PEF pretreatment were extracted with ethanol + SCCO2. The extraction at 200 bar, 333.15, 3.3% wt. of ethanol as cosolvent and using LSB with a PEF pretreatment of 1 kV/cm, produced an extraction yield of 0.284 % and a TAC of 0.231 (g/100 g of ethanol + SCCO2). The individual effect of 1.0 kV/cm of PEF pretreatment increases the %EY by 25 % and the TAC by 29 %. The individual effect of the cosolvent increases the %EY by 32% and that of TAC by 36.4%. However, the combined effect of 1.0 kV cm-1 and 3.3 % ethanol, produced an increase of 78.2 % and 85.3% in the %EY and TAC, respectively. Therefore, these results suggest that there is a synergistic effect, which means that both the electroporation caused by PEF in the LSB and the increase in polarity due to the addition of ethanol produce a substantial improvement over %ET and TAC. Furthermore, the process of extracting anthocyanins from LSB using a mixture of ethanol + supercritical carbon dioxide can be satisfactorily described by a solubility-based model such as the Kumar and Johnston model.The lyophilized strawberry anthocyanins were extracted using a supercritical extraction (SE) process. The effect of pulsed electric fields (PEF) as pretreatment and the influence of the addition of ethanol as a cosolvent on the percentage of extraction yield (EY) and the total anthocyanin concentration (TAC) were analyzed. The effect of PEF was evaluated at 0.5 and 1.0 kV/cm, while the effect of the cosolvent was studied in mixtures of supercritical carbon dioxide - ethanol (SCCO2 + ethanol) at 1.6 and 3.3% by weight. The best results (% EY = 0.506, TAC = 0.428 g /100 g of lyophilized strawberry) were obtained with a PEF pretreatment of 1.0 kV cm-1, 3.3%wt. ethanol at 200 bar and 333.15 K. The experimental results of solubility were suitably adjusted with the Kumar and Johnston model. The maximum solubility (0.114 g/100 g of solvent mixture) was obtained at 300 bar and 313.15 K.The authors would like to thank the National Council of Science and Technology of Mexico (CONACyT) for the scholarship granted to the master’s student in chemical sciences Marco A. Ávila-Hernández

Acumulación simultánea de múltiples metales pesados por cultivos in vitro de plántulas de Prosopis laevigata

Se investigó la capacidad de plántulas de Prosopis laevigata para tolerar y acumular de forma simultánea hasta 4 metales pesados (cromo, níquel, cadmio y plomo), bajo condiciones de cultivo in vitro.Experiments were conducted to investigate the capability of Prosopis laevigata to individually or simultaneously uptake four heavy metals (HM; Cr, Ni, Cd, and Pb). To this end, P. laevigata seedlings were cultured during 50 days on modified MS medium supplemented with 30 g L−1 of sucrose and added with 1, 2, 3 or 4 HM (50 mg L−1 of each HM). When the four HM were added simultaneously, the medium was supplemented with or without ethylenediaminetetracetic acid (EDTA). In the MS media contained only one HM, the seedlings tolerance to HM was as follows: Pb≥Cr>Ni≥Cd. The accumulation of HM from higher to lower concentration in shoots was Pb≥Ni>Cd>>Cr and in roots Cr>>Pb>>Ni>Cd. When the media contained more than one HM, the accumulation in shoots was the highest for Ni and the lowest for Pb, whether EDTA was added or not. EDTA supplementation increased 61, 39, 22, and 3 fold uptake of Cr, Ni, Pb, and Cd in roots, respectively

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat