Current Trends of Bacterial and Fungal Optoproteins for Novel Optical Applications.

Photoproteins, luminescent proteins or optoproteins are a kind of light-response protein responsible for the conversion of light into biochemical energy that is used by some bacteria or fungi to regulate specific biological processes. Within these specific proteins, there are groups such as the photoreceptors that respond to a given light wavelength and generate reactions susceptible to being used for the development of high-novel applications, such as the optocontrol of metabolic pathways. Photoswitchable proteins play important roles during the development of new materials due to their capacity to change their conformational structure by providing/eliminating a specific light stimulus. Additionally, there are bioluminescent proteins that produce light during a heatless chemical reaction and are useful to be employed as biomarkers in several fields such as imaging, cell biology, disease tracking and pollutant detection. The classification of these optoproteins from bacteria and fungi as photoreceptors or photoresponse elements according to the excitation-emission spectrum (UV-Vis-IR), as well as their potential use in novel applications, is addressed in this article by providing a structured scheme for this broad area of knowledge.

Assessment of the tolerance to Fe, Cu and Zn of a sulfidogenic sludge generated from hydrothermal vents sediments as a basis for its application on metals precipitation.

A paramour factor limiting metal-microorganism interaction is the metal ion concentration, and the metal precipitation efficiency driven by microorganisms is sensitive to metal ion concentration. The aim of the work was to determine the tolerance of the sulfidogenic sludge generated from hydrothermal vent sediments at microcosms level to different concentrations of Fe, Cu and Zn and the effect on the microbial community. In this study the chemical oxygen demand (COD) removal, sulfate-reducing activity (SRA) determination, inhibition effect through the determination of IC50, and the characterization of the bacterial community´s diversity were conducted. The IC50 on SRA was 34 and 81 mg/L for Zn and Cu, respectively. The highest sulfide concentration (H2S mg/L) and % of sulfate reduction obtained were: 511.30 ± 0.75 and 35.34 ± 0.51 for 50 mg/L of Fe, 482.48 ± 6.40 and 33.35 ± 0.44 for 10 mg/L of Cu, 442.26 ± 17.1 and 30.57 ± 1.18 for 10 mg/L of Zn, respectively. The COD removal rates were of 71.81 ± 7.6, 53.92 ± 1.07 and 57.68 ± 10.2 mg COD/ L d for Fe (50 mg/L), Cu (40 mg/L) and Zn (20 mg/L), respectively. Proteobacteria, Firmicutes, Chloroflexi and Actinobacteria were common phyla to four microcosms (stabilized sulfidogenic and added with Fe, Cu or Zn). The dsrA genes of Desulfotomaculum acetoxidans, Desulfotomaculum gibsoniae and Desulfovibrio desulfuricans were expressed in the microcosms supporting the SRA results. The consortia could be explored for ex-situ bioremediation purposes in the presence of the metals tested in this work.

Enfermedad cerebrovascular en pacientes ingresados en cuidados intensivos / Cerebrovascular disease in patients admitted to intensive care

RESUMEN Introducción: las enfermedades cerebrovasculares son un problema de salud mundial y representan la tercera causa de muerte, la primera de discapacidad y segunda de demencia. Objetivo: caracterizar clínica y epidemiológicamente la enfermedad cerebrovascular en pacientes ingresados con cuidados intensivos. Métodos: estudio observacional, descriptivo y transversal, efectuado en el Hospital General Docente "Comandante Pinares"", de la provincia de Artemisa, entre 2016 y 2018. De forma probabilística, aleatoria simple, fue seleccionada una muestra de 200 pacientes con enfermedad cerebrovascular. El estudio de las historias clínicas permitió la obtención de información que dio salida a las variables estudiadas, se emplearon para su presentación, métodos de estadística descriptiva. Se respetó la ética médica. Resultados: predominaron los pacientes con 80 años y más (26 %), del sexo masculino (56 %). Fueron frecuentes los accidentes cerebrovasculares isquémicos (83 %) de tipo trombótico (33 %), donde la hipertensión arterial (93,5 %) y el tabaquismo (82 %) fueron los principales factores de riesgo; se tuvo la ventana terapéutica de tres a seis horas (73,5 %) como la más común, predominaron los pacientes vivos, con secuelas al egreso hospitalario (48,5 %). Conclusiones: los pacientes mayores de 80 años y masculinos con factores de riesgos como la hipertensión arterial y tabaquismo, fueron los más propensos al accidente cerebrovascular; los isquémicos y de tipo trombóticos los más comunes, con ventana terapéutica de tres a seis horas en la mayoría de los casos. El mayor número llegó obnubilado y fueron egresados vivos con secuelas.

ABSTRACT Introduction: cerebrovascular diseases are a global health problem and represent the third cause of death, the first cause of disability and the second cause of dementia. Objective: to characterize clinical and epidemiologically cerebrovascular disease in patients admitted to intensive care. Methods: observational, descriptive and cross-sectional study was conducted at "Comandante Pinares" General Hospital, Artemisa province, for the period of 2016-2018. A probabilistic and at simple random sample of 200 patients suffering from cerebrovascular disease was chosen. The study of the clinical histories allowed the collection of output information to the studied variables, using for its presentation methods of descriptive statistics. Medical ethics was respected. Results: patients from 80 years and older predominated (26 %), male sex (56 %). Ischemic cerebrovascular strokes (83 %), thrombotic type (33 %) were frequent, where hypertension (93,5 %) and smoking (82 %) stated as the main risk factors, having the therapeutic window of 3-6 hours (73,5 %) as the most common, alive patients with sequelae at hospital discharged predominated (48,5 %). Conclusions: patients older than 80 years and male, with hypertension and smoking addiction were prone to cerebrovascular stroke, where ischemic and thrombotic types were the most common, with a therapeutic window of three to six hours in the ajority of the cases. The greatest number of patients was admitted with obnubilation and they were discharged alive with sequelae.

Tolerance of a sulfidogenic sludge to trichloroethylene at microcosms level as a basis for a long-term operation of reactors designed for its biodegradation.

Trichloroethylene (TCE) is known as a toxic organic compound found as a pollutant in water streams around the world. The ultimate goal of the present work was to determine the TCE concentration that would be feasible to biodegrade on a long-term basis by a sulfidogenic sludge while maintaining sulfate reducing activity (SRA). Microcosms were prepared with sulfidogenic sludge obtained from a stabilized sulfidogenic UASB and amended with different TCE concentrations (100-300 µM) and two different proportions of volatile fatty acids (VFA) acetate, propionate and butyrate at COD of 2.5:1:1 and 1:1:1, respectively to evaluate the tolerance of the sludge. The overall results suggested that the continuous exposure of the microorganisms to TCE leads to inhibition of SRA; nonetheless, the SRA can be recovered after adequate supplementation of carbon sources and sulfate. The most suitable TCE concentration to operate on a long-term basis while preserving SRA was 26-35 mg L-1 (200-260 µM). A low level of expression of the mRNA of the sulfite reductase subunit alpha (dsrA) gene was obtained in the presence of the TCE and its intermediate products. This gene was associated to SRB belonging to the genera Desulfovibrio, Desulfosalsimonas, Desulfotomaculum, Desulfococcus, Desulfatiglans and Desulfomonas.

Robotic-assisted Roux-en-Y hepaticojejunostomy after bile duct injury.

BACKGROUND: The Da Vinci Robotic Surgical System has positioned itself as a tool that improves the ergonomics of the surgeon, facilitating dissection in confined spaces and enhancing the surgeon's skills. The technical aspects for successful bile duct repair are well-vascularized ducts, tension-free anastomosis, and complete drainage of hepatic segments, and all are achievable with robotic-assisted approach. METHODS: This was a retrospective study of our prospectively collected database of patients with iatrogenic bile duct injury who underwent robotic-assisted Roux-en-Y hepaticojejunostomy. Pre-, intra-, and short-term postoperative data were analyzed. RESULTS: A total of 30 consecutive patients were included. The median age was 46.5 years and 76.7% were female. Neo-confluences with section of hepatic segment IV were performed in 7 patients (those classified as Strasberg E4). In the remaining 23, a Hepp-Couinaud anastomosis was built. There were no intraoperative complications, the median estimated blood loss was 100 mL, and the median operative time was 245 min. No conversion was needed. The median length of stay was 6 days and the median length of follow-up was 8 months. The overall morbidity rate was 23.3%. Two patients presented hepaticojejunostomy leak. No mortality was registered. CONCLUSION: Robotic surgery is feasible and can be safely performed, with acceptable short-term results, in bile duct injury repair providing the advantages of minimally invasive surgery. Further studies with larger number of cases and longer follow-up are needed to establish the role of robotic assisted approaches in the reconstruction of BDI.

Respirometric response and microbial succession of nitrifying sludge to m-cresol pulses in a sequencing batch reactor.

A nitrifying consortium was kinetically, stoichiometrically and molecularly characterized via the in situ pulse respirometric method and pyrosequencing analysis before and after the addition of m-cresol (25 mg C L-1) in a sequencing batch reactor (SBR). Five important kinetic and stoichiometric parameters were determined: the maximum oxygen uptake rate, the maximum nitrification rate, the oxidation yield, the biomass growth yield, and the substrate affinity constant. An inhibitory effect was observed in the nitrification process with a recovery of this by up to eight SBR cycles after m-cresol was added to the system. However, full recovery of the nitrification process was not observed, as the maximum oxygen uptake rate was 25% lower than that of the previous operation without m-cresol addition. Furthermore, the pyrosequencing analyses of the nitrifying consortium after the addition of only two pulses of 25 mg C L-1 m-cresol showed an important microbial community change represented by a decrease in the nitrifying populations and an increase in the populations degrading phenolic compounds.

Characterization of a Marine Microbial Community Used for Enhanced Sulfate Reduction and Copper Precipitation in a Two-Step Process.

Marine microorganisms that are obtained from hydrothermal vent sediments present a great metabolic potential for applications in environmental biotechnology. However, the work done regarding their applications in engineered systems is still scarce. Hence, in this work, the sulfate reduction process carried out by a marine microbial community in an upflow anaerobic sludge blanket (UASB) reactor was investigated for 190 days under sequential batch mode. The effects of 1000 to 5500 mg L-1 of SO4-2 and the chemical oxygen demand (COD)/SO4-2 ratio were studied along with a kinetic characterization with lactate as the electron donor. Also, the feasibility of using the sulfide produced in the UASB for copper precipitation in a second column was studied under continuous mode. The system presented here is an alternative to sulfidogenesis, particularly when it is necessary to avoid toxicity to sulfide and competition with methanogens. The bioreactor performed better with relatively low concentrations of sulfate (up to 1100 mg L-1) and COD/SO4-2 ratios between 1.4 and 3.6. Under the continuous regime, the biogenic sulfide was sufficient to precipitate copper at a removal rate of 234 mg L-1 day-1. Finally, the identification of the microorganisms in the sludge was carried out; some genera of microorganisms identified were Desulfitobacterium and Clostridium.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor.

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

High sulfate reduction efficiency in a UASB using an alternative source of sulfidogenic sludge derived from hydrothermal vent sediments.

Sulfidogenesis in reactors is mostly achieved through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. In this work, an upflow anaerobic sludge blanket (UASB) reactor operated under sulfate-reducing conditions was inoculated with hydrothermal vent sediments to carry out sulfate reduction using volatile fatty acids (VFAs) as substrate and chemical oxygen demand (COD)/SO4 (-2) ratios between 0.49 and 0.64. After a short period of adaptation, a robust non-granular sludge was capable of achieving high sulfate reduction efficiencies while avoiding competence with methanogens and toxicity to the microorganisms due to high sulfide concentration. The highest sulfide concentration (2,552 mg/L) was obtained with acetate/butyrate, and sulfate reduction efficiencies were up to 98 %. A mixture of acetate/butyrate, which produced a higher yielding of HS(-), was preferred over acetate/propionate/butyrate since the consumption of COD was minimized during the process. Sludge was analyzed, and some of the microorganisms identified in the sludge belong to the genera Desulfobacterium, Marinobacter, and Clostridium. The tolerance of the sludge to sulfide may be attributed to the syntrophy among these microorganisms, some of which have been reported to tolerate high concentrations of sulfide. To the best of our knowledge, this is the first report on the analysis of the direct utilization of hydrothermal vent sediments as an alternate source of sludge for sulfate reduction under high sulfide concentrations.

Assessment of methane biodegradation kinetics in two-phase partitioning bioreactors by pulse respirometry.

Biological methane biodegradation is a promising treatment alternative when the methane produced in waste management facilities cannot be used for energy generation. Two-phase partitioning bioreactors (TPPBs), provided with a non-aqueous phase (NAP) with high affinity for the target pollutant, are particularly suitable for the treatment of poorly water-soluble compounds such as methane. Nevertheless, little is known about the influence of the presence of the NAP on the resulting biodegradation kinetics in TPPBs. In this study, an experimental framework based on the in situ pulse respirometry technique was developed to assess the impact of NAP addition on the methane biodegradation kinetics using Methylosinus sporium as a model methane-degrading microorganism. A comprehensive mass transfer characterization was performed in order to avoid mass transfer limiting scenarios and ensure a correct kinetic parameter characterization. The presence of the NAP mediated significant changes in the apparent kinetic parameters of M. sporium during methane biodegradation, with variations of 60, 120, and 150% in the maximum oxygen uptake rate, half-saturation constant and maximum specific growth rate, respectively, compared with the intrinsic kinetic parameters retrieved from a control without NAP. These significant changes in the kinetic parameters mediated by the NAP must be considered for the design, operation and modeling of TPPBs devoted to air pollution control.

Pulse respirometry in two-phase partitioning bioreactors: case study of terephthalic acid biodegradation.

Two-phase partitioning bioreactors (TPPBs) are based on the addition of an organic phase, often called vector, to a bioreactor in order to increase mass transfer of oxygen or gaseous substrates from the gaseous phase to the aqueous phase. In TPPBs, like in any other reactor design, the characterization of the bioprocess is often required for design, control, and operation purposes. Pulse respirometry is a method that allows for microbial processes characterization through the determination of several stoichiometric and kinetic parameters with relatively little experimental effort. Despite its interest and its previous application in countless applications, pulse respirometry has never been applied in TPPBs. In this work, pulse respirometry was assessed in a model TPPB degrading terephthalic acid and using Elvax™ as solid vector to enhance oxygen transfer. The results indicated that the addition of 10 to 20% Elvax increased oxygen transfer by up to 97%, compared to control with no vector. Pulse respirometry was successfully applied and allowed for the determination of the growth yield, the substrate affinity constant, and the maximum growth rate, within other. It is concluded that pulse respirometry is a useful method, not only for the characterization of processes in TPPBs but also for the selection of a vector within several brands commercially available.

Kinetic and stoichiometric characterization of a fixed biofilm reactor by pulse respirometry.

An in situ respirometric technique was applied to a sequential biofilm batch reactor treating a synthetic wastewater containing acetate. In this reactor, inoculated with mixed liquor from a wastewater plant, unglazed ceramic tiles were used as support media while maintaining complete mixing regime. A total of 8 kinetic and stoichiometric parameters were determined by in situ pulse respirometry; namely substrate oxidation yield, biomass growth yield, storage yield, storage growth yield, substrate affinity constant, storage affinity constant, storage kinetic constant and maximum oxygen uptake rate. Additionally, biofilm growth was determined from support media sampling showing that the colonization process occurred during the first 40 days, reaching an apparent steady-state afterward. Similarly, most of the stoichiometric and kinetic parameters were changing over time but reached steady values after day 40. During the experiment, the respirometric method allowed to quantify the amount of substrate directed to storage, which was significant, especially at substrate concentration superior to 30mg CODL(-1). The Activated Sludge Model 3 (ASM3), which is a model that takes into account substrate storage mechanisms, fitted well experimental data and allowed confirming that feast and famine cycles in SBR favor storage. These results also show that in situ pulse respirometry can be used for fixed-bed reactors characterization.

Comparative expression profiles for KiSS-1 and REN genes in preeclamptic and healthy placental tissues.

OBJECTIVE: The aim of the present work was to look at differences in the placental tissue expression of KiSS-1 and REN genes from preeclamptic and healthy pregnant women, that could account for a possible synergistic function for both genes in the pathogenesis of preeclampsia. STUDY DESIGN: This case-control study involved 27 preeclamptic women and 27 normoevolutive pregnant women. cDNA was obtained from placental tissue to carry out qPCR for both KiSS-1 and REN genes in order to compare mRNA expression levels in the studied groups. Statistical analysis showed expression differences that correlate with clinical and/or biochemical variables. RESULTS: Higher expression for KiSS-1 in PEE vs. control woman (p=0.001) was observed, whereas no difference was observed for REN expression (p=0.300) when all the subjects were included. However, REN expression was significant higher when the samples were stratified according to preeclampsia severity. For 18 mild preeclamptic patients the p-value was p=0.001 compared to their controls, while for the remaining nine with severe preeclampsia the expression became significant (p=0.001). CONCLUSION: Our results suggest that the high KiSS-1 expression seen in preeclamptic patients is in accordance with its role as an inhibitor of trophoblast invasiveness and maintained until the end of gestation. On the other hand, aggressive therapeutic management and/or severity status of patients have a direct effect on placental REN expression levels, masking the natural high expression of this gene on preeclamptic placental tissue. Therefore it was not possible to establish a real concordant expression profile for KiSS-1 and REN genes.

New insights on O2 uptake mechanisms in two-phase partitioning bioreactors.

Numerous reports show that both transfer and uptake of poorly-water soluble substrates are significantly enhanced in two-phase partitioning bioreactors (TPPBs). A number of hypotheses have been put forward to explain these enhancements and among them, the occurrence of direct substrate or oxygen uptake from the vector/water interface has been suggested. The objective of this paper was to quantify the direct oxygen uptake from the vector/water interface in a culture of Pseudomonas putida, performed in a stirred tank reactor, using glucose as substrate and silicone oil as vector. Despite of a sufficient dissolved O(2) concentration in the vector phase (17 mg l(-1)) and a significant vector surface area (4,000 m(-1)) no significant direct O(2) uptake from the vector/water interface was observed, compared to O(2) uptake from the aqueous phase. From these results it was concluded that, direct O(2) or substrate uptake from the vector/water interface might not be significant in TPPBs.

Kinetic and stoichiometric parameters estimation in a nitrifying bubble column through "in-situ" pulse respirometry.

This article proposes a simple "in-situ" pulse respirometric method for the estimation of four important kinetic and stoichiometric parameters. The method is validated in a suspended biomass nitrifying reactor for the determination of (i) maximum oxygen uptake rate (OUR(ex)max), (ii) oxidation yield (f(E)), (iii) biomass growth yield (f(S)), and (iv) affinity constant (K(S)). OUR(ex)max and f(E) were directly obtained from respirograms. In the presented case study, a minimum substrate pulse of 10 mgNH(4) (+)-N L(-1) was necessary to determine OUR(ex)max which was 61.15 +/- 4.09 mgO(2) L(-1) h(-1) (5 repetitions). A linear correlation (r(2) = 0.93) obtained between OUR(ex)max and the biomass concentration in the reactor suggests that biomass concentration can be estimated from respirometric experiments. The substrate oxidation yield, f(E), was determined along 60 days of continuous operation with an average error of 5.6%. The biomass growth yield was indirectly estimated from the substrate oxidation yield f(E). The average obtained value (0.10 +/- 0.04 mgCOD mg(-1)COD) was in accordance with the f(S) estimation by the traditional COD mass balance method under steady-state conditions (0.09 +/- 0.01). The affinity constant K(S) was indirectly estimated after fitting the ascending part of the respirogram to a theoretical model. An average value of 0.48 +/- 0.08 mgNH(4) (+)-N L(-1) was obtained, which is in the range of affinity constants reported in the literature for the nitrification process (0.16-2 mgNH(4) (+)-N L(-1)).