Climate change induces shifts in coastal Baltic Sea surface water microorganism stress and photosynthesis gene expression.

The world's oceans are challenged by climate change linked warming with typically highly populated coastal areas being particularly susceptible to these effects. Many studies of climate change on the marine environment use large, short-term temperature manipulations that neglect factors such as long-term adaptation and seasonal cycles. In this study, a Baltic Sea 'heated' bay influenced by thermal discharge since the 1970s from a nuclear reactor (in relation to an unaffected nearby 'control' bay) was used to investigate how elevated temperature impacts surface water microbial communities and activities. 16S rRNA gene amplicon based microbial diversity and population structure showed no difference in alpha diversity in surface water microbial communities, while the beta diversity showed a dissimilarity between the bays. Amplicon sequencing variant relative abundances between the bays showed statistically higher values for, e.g., Ilumatobacteraceae and Burkholderiaceae in the heated and control bays, respectively. RNA transcript-derived activities followed a similar pattern in alpha and beta diversity with no effect on Shannon's H diversity but a significant difference in the beta diversity between the bays. The RNA data further showed more elevated transcript counts assigned to stress related genes in the heated bay that included heat shock protein genes dnaKJ, the co-chaperonin groS, and the nucleotide exchange factor heat shock protein grpE. The RNA data also showed elevated oxidative phosphorylation transcripts in the heated (e.g., atpHG) compared to control (e.g., atpAEFB) bay. Furthermore, genes related to photosynthesis had generally higher transcript numbers in the control bay, such as photosystem I (psaAC) and II genes (psbABCEH). These increased stress gene responses in the heated bay will likely have additional cascading effects on marine carbon cycling and ecosystem services.

Baltic Sea coastal sediment-bound eukaryotes have increased year-round activities under predicted climate change related warming.

Climate change related warming is a serious environmental problem attributed to anthropogenic activities, causing ocean water temperatures to rise in the coastal marine ecosystem since the last century. This particularly affects benthic microbial communities, which are crucial for biogeochemical cycles. While bacterial communities have received considerable scientific attention, the benthic eukaryotic community response to climate change remains relatively overlooked. In this study, sediments were sampled from a heated (average 5°C increase over the whole year for over 50 years) and a control (contemporary conditions) Baltic Sea bay during four different seasons across a year. RNA transcript counts were then used to investigate eukaryotic community changes under long-term warming. The composition of active species in the heated and control bay sediment eukaryotic communities differed, which was mainly attributed to salinity and temperature. The family level RNA transcript alpha diversity in the heated bay was higher during May but lower in November, compared with the control bay, suggesting altered seasonal activity patterns and dynamics. In addition, structures of the active eukaryotic communities varied between the two bays during the same season. Hence, this study revealed that long-term warming can change seasonality in eukaryotic diversity patterns. Relative abundances and transcript expression comparisons between bays suggested that some taxa that now have lower mRNA transcripts numbers could be favored by future warming. Furthermore, long-term warming can lead to a more active metabolism in these communities throughout the year, such as higher transcript numbers associated with diatom energy production and protein synthesis in the heated bay during winter. In all, these data can help predict how future global warming will affect the ecology and metabolism of eukaryotic community in coastal sediments.

Enduring education and employment: Examining motivation and mechanisms of psychological resilience.

Resilience, the ability to bounce back from difficult events, is critical for an individual to negotiate stressors and adversity. Despite being widely studied, little is known about the processes involved in the development of resilience. The goal of the studies are to investigate the relationship between motivation orientation, emotional intelligence, cognitive appraisals, and psychological resilience. Two studies, using self-report questionnaires were conducted with employed young adults also enrolled in post-secondary studies (pre- and during the pandemic) to test the tenability of our proposed models. Study 1 and Study 2 showed that emotional intelligence and challenge appraisals were mediators of autonomous motivation and resilience. Study 2 revealed statistically significant differences in mean scores of autonomous motivation and emotional intelligence between non-pandemic students and pandemic students. Based on the findings, it is suggested that autonomous motivation, emotional intelligence, and challenge appraisals are important aptitudes for the development of resilience. Furthermore, findings suggest that social isolation caused by the pandemic may have affected levels of emotional intelligence. Ultimately, the research expands the literature on both self-determination theory and resilience by offering a unique multiple mediation model for predicting the development of resilience within the employed undergraduate population.

Quantitative proteomics reveals unique responses to antimicrobial treatments in clinical Pseudomonas aeruginosa isolates.

IMPORTANCE: Pseudomonas aeruginosa is an important pathogen often associated with hospital-acquired infections and chronic lung infections in people with cystic fibrosis. P. aeruginosa possesses a wide array of intrinsic and adaptive mechanisms of antibiotic resistance, and the regulation of these mechanisms is complex. Label-free quantitative proteomics is a powerful tool to compare susceptible and resistant strains of bacteria and their responses to antibiotic treatments. Here we compare the proteomes of three isolates of P. aeruginosa with different antibiotic resistance profiles in response to five challenge conditions. We uncover unique and shared proteome changes for the widely used laboratory strain PAO1 and two isolates of the Liverpool epidemic strain of P. aeruginosa, LESlike1 and LESB58. Our data set provides insight into antibiotic resistance in clinically relevant Pseudomonas isolates and highlights proteins, including those with uncharacterized functions, which can be further investigated for their role in adaptive responses to antibiotic treatments.

Inhibiting fatty acid synthesis overcomes colistin resistance.

Treating multidrug-resistant infections has increasingly relied on last-resort antibiotics, including polymyxins, for example colistin. As polymyxins are given routinely, the prevalence of their resistance is on the rise and increases mortality rates of sepsis patients. The global dissemination of plasmid-borne colistin resistance, driven by the emergence of mcr-1, threatens to diminish the therapeutic utility of polymyxins from an already shrinking antibiotic arsenal. Restoring sensitivity to polymyxins using combination therapy with sensitizing drugs is a promising approach to reviving its clinical utility. Here we describe the ability of the biotin biosynthesis inhibitor, MAC13772, to synergize with colistin exclusively against colistin-resistant bacteria. MAC13772 indirectly disrupts fatty acid synthesis (FAS) and restores sensitivity to the last-resort antibiotic, colistin. Accordingly, we found that combinations of colistin and other FAS inhibitors, cerulenin, triclosan and Debio1452-NH3, had broad potential against both chromosomal and plasmid-mediated colistin resistance in chequerboard and lysis assays. Furthermore, combination therapy with colistin and the clinically relevant FabI inhibitor, Debio1452-NH3, showed efficacy against mcr-1 positive Klebsiella pneumoniae and colistin-resistant Escherichia coli systemic infections in mice. Using chemical genomics, lipidomics and transcriptomics, we explored the mechanism of the interaction. We propose that inhibiting FAS restores colistin sensitivity by depleting lipid synthesis, leading to changes in phospholipid composition. In all, this work reveals a surprising link between FAS and colistin resistance.

Long-term warming modulates diversity, vertical structuring of microbial communities, and sulfate reduction in coastal Baltic Sea sediments.

Coastal waters such as those found in the Baltic Sea already suffer from anthropogenic related problems including increased algal blooming and hypoxia while ongoing and future climate change will likely worsen these effects. Microbial communities in sediments play a crucial role in the marine energy- and nutrient cycling, and how they are affected by climate change and shape the environment in the future is of great interest. The aims of this study were to investigate potential effects of prolonged warming on microbial community composition and nutrient cycling including sulfate reduction in surface (∼0.5 cm) to deeper sediments (∼ 24 cm). To investigate this, 16S rRNA gene amplicon sequencing was performed, and sulfate concentrations were measured and compared between sediments in a heated bay (which has been used as a cooling water outlet from a nearby nuclear power plant for approximately 50 years) and a nearby but unaffected control bay. The results showed variation in overall microbial diversity according to sediment depth and higher sulfate flux in the heated bay compared to the control bay. A difference in vertical community structure reflected increased relative abundances of sulfur oxidizing- and sulfate reducing bacteria along with a higher proportion of archaea, such as Bathyarchaeota, in the heated compared to the control bay. This was particularly evident closer to the sediment surface, indicating a compression of geochemical zones in the heated bay. These results corroborate findings in previous studies and additionally point to an amplified effect of prolonged warming deeper in the sediment, which could result in elevated concentrations of toxic compounds and greenhouse gases closer to the sediment surface.

Climate change-related warming reduces thermal sensitivity and modifies metabolic activity of coastal benthic bacterial communities.

Besides long-term average temperature increases, climate change is projected to result in a higher frequency of marine heatwaves. Coastal zones are some of the most productive and vulnerable ecosystems, with many stretches already under anthropogenic pressure. Microorganisms in coastal areas are central to marine energy and nutrient cycling and therefore, it is important to understand how climate change will alter these ecosystems. Using a long-term heated bay (warmed for 50 years) in comparison with an unaffected adjacent control bay and an experimental short-term thermal (9 days at 6-35 °C) incubation experiment, this study provides new insights into how coastal benthic water and surface sediment bacterial communities respond to temperature change. Benthic bacterial communities in the two bays reacted differently to temperature increases with productivity in the heated bay having a broader thermal tolerance compared with that in the control bay. Furthermore, the transcriptional analysis showed that the heated bay benthic bacteria had higher transcript numbers related to energy metabolism and stress compared to the control bay, while short-term elevated temperatures in the control bay incubation experiment induced a transcript response resembling that observed in the heated bay field conditions. In contrast, a reciprocal response was not observed for the heated bay community RNA transcripts exposed to lower temperatures indicating a potential tipping point in community response may have been reached. In summary, long-term warming modulates the performance, productivity, and resilience of bacterial communities in response to warming.

Long-Term Warming of Baltic Sea Coastal Waters Affects Bacterial Communities in Bottom Water and Sediments Differently.

Coastal marine ecosystems are some of the most diverse natural habitats while being highly vulnerable in the face of climate change. The combination of anthropogenic influence from land and ongoing climate change will likely have severe effects on the environment, but the precise response remains uncertain. This study compared an unaffected "control" Baltic Sea bay to a "heated" bay that has undergone artificial warming from cooling water release from a nuclear power plant for ~50 years. This heated the water in a similar degree to IPCC SSP5-8.5 predictions by 2100 as natural systems to study temperature-related climate change effects. Bottom water and surface sediment bacterial communities and their biogeochemical processes were investigated to test how future coastal water warming alters microbial communities; shifts seasonal patterns, such as increased algae blooming; and influences nutrient and energy cycling, including elevated respiration rates. 16S rRNA gene amplicon sequencing and geochemical parameters demonstrated that heated bay bottom water bacterial communities were influenced by increased average temperatures across changing seasons, resulting in an overall Shannon's H diversity loss and shifts in relative abundances. In contrast, Shannon's diversity increased in the heated surface sediments. The results also suggested a trend toward smaller-sized microorganisms within the heated bay bottom waters, with a 30% increased relative abundance of small size picocyanobacteria in the summer (June). Furthermore, bacterial communities in the heated bay surface sediment displayed little seasonal variability but did show potential changes of long-term increased average temperature in the interplay with related effects on bottom waters. Finally, heated bay metabolic gene predictions from the 16S rRNA gene sequences suggested raised anaerobic processes closer to the sediment-water interface. In conclusion, climate change will likely alter microbial seasonality and diversity, leading to prolonged and increased algae blooming and elevated respiration rates within coastal waters.

Weakened resilience of benthic microbial communities in the face of climate change.

Increased ocean temperature associated with climate change is especially intensified in coastal areas and its influence on microbial communities and biogeochemical cycling is poorly understood. In this study, we sampled a Baltic Sea bay that has undergone 50 years of warmer temperatures similar to RCP5-8.5 predictions due to cooling water release from a nuclear power plant. The system demonstrated reduced oxygen concentrations, decreased anaerobic electron acceptors, and higher rates of sulfate reduction. Chemical analyses, 16S rRNA gene amplicons, and RNA transcripts all supported sediment anaerobic reactions occurring closer to the sediment-water interface. This resulted in higher microbial diversities and raised sulfate reduction and methanogenesis transcripts, also supporting increased production of toxic sulfide and the greenhouse gas methane closer to the sediment surface, with possible release to oxygen deficient waters. RNA transcripts supported prolonged periods of cyanobacterial bloom that may result in increased climate change related coastal anoxia. Finally, while metatranscriptomics suggested increased energy production in the heated bay, a large number of stress transcripts indicated the communities had not adapted to the increased temperature and had weakened resilience. The results point to a potential feedback loop, whereby increased temperatures may amplify negative effects at the base of coastal biochemical cycling.

Interplay between eutrophication and climate warming on bacterial communities in coastal sediments differs depending on water depth and oxygen history.

Coastal aquatic systems suffer from nutrient enrichment, which results in accelerated eutrophication effects due to increased microbial metabolic rates. Climate change related prolonged warming will likely accelerate existing eutrophication effects, including low oxygen concentrations. However, how the interplay between these environmental changes will alter coastal ecosystems is poorly understood. In this study, we compared 16S rRNA gene amplicon based bacterial communities in coastal sediments of a Baltic Sea basin in November 2013 and 2017 at three sites along a water depth gradient with varying bottom water oxygen histories. The shallow site showed changes of only 1.1% in relative abundance of bacterial populations in 2017 compared to 2013, while the deep oxygen-deficient site showed up to 11% changes in relative abundance including an increase of sulfate-reducing bacteria along with a 36% increase in organic matter content. The data suggested that bacterial communities in shallow sediments were more resilient to seasonal oxygen decline, while bacterial communities in sediments subjected to long-term hypoxia seemed to be sensitive to oxygen changes and were likely to be under hypoxic/anoxic conditions in the future. Our data demonstrate that future climate changes will likely fuel eutrophication related spread of low oxygen zones.

Towards Bioleaching of a Vanadium Containing Magnetite for Metal Recovery.

Vanadium - a transition metal - is found in the ferrous-ferric mineral, magnetite. Vanadium has many industrial applications, such as in the production of high-strength low-alloy steels, and its increasing global industrial consumption requires new primary sources. Bioleaching is a biotechnological process for microbially catalyzed dissolution of minerals and wastes for metal recovery such as biogenic organic acid dissolution of bauxite residues. In this study, 16S rRNA gene amplicon sequencing was used to identify microorganisms in Nordic mining environments influenced by vanadium containing sources. These data identified gene sequences that aligned to the Gluconobacter genus that produce gluconic acid. Several strategies for magnetite dissolution were tested including oxidative and reductive bioleaching by acidophilic microbes along with dissimilatory reduction by Shewanella spp. that did not yield significant metal release. In addition, abiotic dissolution of the magnetite was tested with gluconic and oxalic acids, and yielded 3.99 and 81.31% iron release as a proxy for vanadium release, respectively. As a proof of principle, leaching via gluconic acid production by Gluconobacter oxydans resulted in a maximum yield of 9.8% of the available iron and 3.3% of the vanadium. Addition of an increased concentration of glucose as electron donor for gluconic acid production alone, or in combination with calcium carbonate to buffer the pH, increased the rate of iron dissolution and final vanadium recoveries. These data suggest a strategy of biogenic organic acid mediated vanadium recovery from magnetite and point the way to testing additional microbial species to optimize the recovery.

The molecular basis of regulation of bacterial capsule assembly by Wzc.

Bacterial extracellular polysaccharides (EPSs) play critical roles in virulence. Many bacteria assemble EPSs via a multi-protein "Wzx-Wzy" system, involving glycan polymerization at the outer face of the cytoplasmic/inner membrane. Gram-negative species couple polymerization with translocation across the periplasm and outer membrane and the master regulator of the system is the tyrosine autokinase, Wzc. This near atomic cryo-EM structure of dephosphorylated Wzc from E. coli shows an octameric assembly with a large central cavity formed by transmembrane helices. The tyrosine autokinase domain forms the cytoplasm region, while the periplasmic region contains small folded motifs and helical bundles. The helical bundles are essential for function, most likely through interaction with the outer membrane translocon, Wza. Autophosphorylation of the tyrosine-rich C-terminus of Wzc results in disassembly of the octamer into multiply phosphorylated monomers. We propose that the cycling between phosphorylated monomer and dephosphorylated octamer regulates glycan polymerization and translocation.

FtsA G50E mutant suppresses the essential requirement for FtsK during bacterial cell division in Escherichia coli.

In Escherichia coli, the N-terminal domain of the essential protein FtsK (FtsKN) is proposed to modulate septum formation through the formation of dynamic and essential protein interactions with both the Z-ring and late-stage division machinery. Using genomic mutagenesis, complementation analysis, and in vitro pull-down assays, we aimed to identify protein interaction partners of FtsK essential to its function during division. Here, we identified the cytoplasmic Z-ring membrane anchoring protein FtsA as a direct protein-protein interaction partner of FtsK. Random genomic mutagenesis of an ftsK temperature-sensitive strain of E. coli revealed an FtsA point mutation (G50E) that is able to fully restore normal cell growth and morphology, and further targeted site-directed mutagenesis of FtsA revealed several other point mutations capable of fully suppressing the essential requirement for functional FtsK. Together, this provides insight into a potential novel co-complex formed between these components during division and suggests FtsA may directly impact FtsK function.

Resuscitation with Hydroxyethyl Starch Maintains Hemodynamic Coherence in Ovine Hemorrhagic Shock.

BACKGROUND: Fluid resuscitation in hemorrhagic shock aims to restore hemodynamics and repair altered microcirculation. Hemodynamic coherence is the concordant performance of macro- and microcirculation. The present study on fluid therapy in hemorrhagic shock hypothesized that the choice of fluid (0.9% sodium chloride [saline group] or balanced 6% hydroxyethyl starch 130/0.4 [hydroxyethyl starch group]) impacts on hemodynamic coherence. METHODS: After instrumentation, 10 sheep were bled up to 30 ml/kg body weight of blood stopping at a mean arterial pressure of 30 mmHg to establish hemorrhagic shock. To reestablish baseline mean arterial pressure, they received either saline or hydroxyethyl starch (each n = 5). Hemodynamic coherence was assessed by comparison of changes in mean arterial pressure and both perfused vessel density and microvascular flow index. RESULTS: Bleeding of 23 ml/kg blood [21; 30] (median [25th; 75th percentile]) in the saline group and 24 ml/kg [22; 25] (P = 0.916) in the hydroxyethyl starch group led to hemorrhagic shock. Fluid resuscitation reestablished baseline mean arterial pressure in all sheep of the hydroxyethyl starch group and in one sheep of the saline group. In the saline group 4,980 ml [3,312; 5,700] and in the hydroxyethyl starch group 610 ml [489; 615] of fluid were needed (P = 0.009). In hemorrhagic shock perfused vessel density (saline from 100% to 83% [49; 86]; hydroxyethyl starch from 100% to 74% [61; 80]) and microvascular flow index (saline from 3.1 [2.5; 3.3] to 2.0 [1.6; 2.3]; hydroxyethyl starch from 2.9 [2.9; 3.1] to 2.5 [2.3; 2.7]) decreased in both groups. After resuscitation both variables improved in the hydroxyethyl starch group (perfused vessel density: 125% [120; 147]; microvascular flow index: 3.4 [3.2; 3.5]), whereas in the saline group perfused vessel density further decreased (64% [62; 79]) and microvascular flow index increased less than in the hydroxyethyl starch group (2.7 [2.4; 2.8]; both P < 0.001 for saline vs. hydroxyethyl starch). CONCLUSIONS: Resuscitation with hydroxyethyl starch maintained coherence in hemorrhagic shock. In contrast, saline only improved macro- but not microcirculation. Hemodynamic coherence might be influenced by the choice of resuscitation fluid.

Association of sublingual microcirculation parameters and endothelial glycocalyx dimensions in resuscitated sepsis.

BACKGROUND: The endothelial glycocalyx (eGC) covers the luminal surface of the vascular endothelium and plays an important protective role in systemic inflammatory states and particularly in sepsis. Its breakdown leads to capillary leak and organ dysfunction. Moreover, sepsis-induced alterations of sublingual microcirculation are associated with a worse clinical outcome. The present study was performed to investigate the associations between eGC dimensions and established parameters of microcirculation dysfunction in sepsis. METHODS: This observational, prospective, cross-sectional study included 40 participants, of which 30 critically ill septic patients were recruited from intensive care units of a university hospital and 10 healthy volunteers served as controls. The established microcirculation parameters were obtained sublingually and analyzed according to the current recommendations. In addition, the perfused boundary region (PBR), an inverse parameter of the eGC dimensions, was measured sublingually, using novel data acquisition and analysis software (GlycoCheck™). Moreover, we exposed living endothelial cells to 5% serum from a subgroup of study participants, and the delta eGC breakdown, measured with atomic force microscopy (AFM), was correlated with the paired PBR values. RESULTS: In septic patients, sublingual microcirculation was impaired, as indicated by a reduced microvascular flow index (MFI) and a reduced proportion of perfused vessels (PPV) compared to those in healthy controls (MFI, 2.93 vs 2.74, p = 0.002; PPV, 98.53 vs 92.58, p = 0.0004). PBR values were significantly higher in septic patients compared to those in healthy controls, indicating damage of the eGC (2.04 vs 2.34, p < 0.0001). The in vitro AFM data correlated exceptionally well with paired PBR values obtained at the bedside (rs = - 0.94, p = 0.02). Both PBR values and microcirculation parameters correlated well with the markers of critical illness. Interestingly, no association was observed between the PBR values and established microcirculation parameters. CONCLUSION: Our findings suggest that eGC damage can occur independently of microcirculatory impairment as measured by classical consensus parameters. Further studies in critically ill patients are needed to unravel the relationship of glycocalyx damage and microvascular impairment, as well as their prognostic and therapeutic importance in sepsis. TRIAL REGISTRATION: Retrospectively registered: Clinicaltrials.gov, NCT03960307.

Differential Effects of Selective and Nonselective Potassium Channel Inhibitors in Ovine Endotoxemic Shock (Macrocirculation) and in a Rat Model of Septic Shock (Microcirculation).

BACKGROUND: Potassium-(K)-channel inhibitors may increase systemic vascular resistance in vasodilatory shock states. OBJECTIVE: The purpose of the present study was to compare the macro- and microvascular effects of the adenosine triphosphate-sensitive K-channel-(KATP)-inhibitor glipizide and the nonselective K-channel inhibitor tetraethylammonium (TEA) in ovine endotoxemic shock and septic shock in rats. DESIGN: Two randomized, controlled laboratory studies. ANIMALS: Thirty female sheep and 40 male Sprague Dawley rats. SETTING: Animal research facility INTERVENTION:: Systemic hemodynamics were analyzed in ovine endotoxemic shock with guideline-oriented supportive therapy. Sheep were allocated to three treatment groups for 12 h: glipizide 10 mg kg·h, TEA 8 mg kg·h, or 0.9% saline. The microvascular effects of each drug were evaluated in septic rats (cecal ligation and puncture model) receiving a 2-h infusion of each study drug: glipizide 20 mg kg·h; TEA 50 mg kg·h, or 0.9% saline, respectively, followed by intravital microscopy of villi microcirculation. RESULTS: Compared with the control group, glipizide infusion increased systemic vascular resistance index and decreased cardiac index and heart rate (HR) in sheep (P < 0.05), whereas TEA infusion decreased HR and resulted in a decreased survival time (P = 0.001). In rats, glipizide infusion resulted in an increase in mean arterial pressure and a decrease in HR compared with baseline measurement (P < 0.05) without relevant effects on the villi microcirculation. TEA decreased HR and decreased capillary perfusion of the villi microcirculation compared with the sham group (P = 0.002). CONCLUSIONS: Selective inhibition of KATP-channels in ovine endotoxemic shock with glipizide partially restored vasomotor tone without exerting harmful effects on intestinal microcirculation in septic shock in rats. On the contrary, nonselective K-channel inhibition with TEA showed deleterious effects in both models, including impaired microcirculation and decreased survival time. Future research on glipizide in vasodilatory shock may be warranted.

Haloalkaliphilic microorganisms assist sulfide removal in a microbial electrolysis cell.

Several industrial processes produce toxic sulfide containing streams that are often scrubbed using caustic solutions. An alternative, cost effective sulfide treatment method is bioelectrochemical sulfide removal. For the first time, a haloalkaliphilic sulfide-oxidizing microbial consortium was introduced to the anodic chamber of a microbial electrolysis cell operated at alkaline pH and with 1.0 M sodium ions. Under anode potential control, the highest sulfide removal rate was 2.16 mM/day and chemical analysis supported that the electrical current generation was from the sulfide oxidation. Biotic operation produced a maximum current density of 3625 mA/m2 compared to 210 mA/m2 while under abiotic operation. Furthermore, biotic electrical production was maintained for a longer period than for abiotic operation, potentially due to the passivation of the electrode by elemental sulfur during abiotic operation. The use of microorganisms reduced the energy input in this study compared to published electrochemical sulfide removal technologies. Sulfide-oxidizing populations dominated both the planktonic and electrode-attached communities with 16S rRNA gene sequences aligning within the genera Thioalkalivibrio, Thioalkalimicrobium, and Desulfurivibrio. The dominance of the Desulfurivibrio-like population on the anode surface offered evidence for the first haloalkaliphilic bacterium able to couple electrons from sulfide oxidation to extracellular electron transfer to the anode.

Monitoring of Conjunctival Microcirculation Reflects Sublingual Microcirculation in Ovine Septic and Hemorrhagic Shock.

INTRODUCTION: The conjunctival region may serve as an alternative site for microcirculatory measurements. The present study was performed to investigate the correlation of sublingual and conjunctival microcirculation in ovine models of septic and hemorrhagic shock. METHODS: Septic shock was induced in 10 sheep by inoculation of feces into the peritoneal cavity until mean arterial pressure (MAP) was <60 mm Hg and arterial lactate level was ≥1.8 mmol· L. In another 10 sheep, hemorrhagic shock was induced by stepwise blood withdrawal of 3×10 mL·kg. Systemic hemodynamics and parameters of blood gas analysis were analyzed. Conjunctival and sublingual microcirculation were monitored and analyzed according to current recommendations. Parameters were measured at baseline and at shock time. RESULTS: Septic shock resulted in a significant drop in MAP and cardiac index (CI), and an increase in arterial lactate levels. While the total vessel density (TVD) in the sublingual microcirculation was relatively well maintained, the perfused vessel density (PVD) and the microvascular flow index (MFI) were significantly reduced in septic shock. Hemorrhagic shock reduced MAP and CI, and increased arterial lactate levels. TVD was relatively unchanged in hemorrhagic shock, while PVD and MFI were significantly decreased. The conjunctival microcirculation showed similar changes to the sublingual microcirculation in both models. CONCLUSIONS: The findings of the current study support the proposed use of the conjunctiva as an alternative site for microcirculatory monitoring in hemorrhagic and septic shock. Further studies should focus on the impact of therapy and the loss of correlation between the different microcirculatory regions in advanced shock.

Sole causal therapy worsens outcome as compared to no therapy and combined causal and goal-directed supportive therapy in ovine septic shock.

BACKGROUND: There is clear evidence that early causal therapy improves outcome in sepsis and septic shock, whereas recent studies on supportive hemodynamic therapy have produced very conflictive results. The objective of the present study was to determine whether a supportive hemodynamic therapy guided by clinically relevant invasive monitoring improves survival and organ function in a high-lethality model of septic shock in sheep as compared to sole causal therapy including surgical and antimicrobial treatment. METHODS: Twenty healthy ewes were anaesthetized and instrumented for hemodynamic surveillance. After laparotomy and fecal withdrawal from the caecum, animals were randomly assigned to one of four groups: sham, control, causal and combined therapy. In all groups but the sham group, feces were injected into the peritoneal cavity. Septic shock was defined as mean arterial pressure (MAP) ≤60 mmHg and arterial lactate concentration ≥1.8 mmol·L-1. Animals of the control group received no therapy, while the causal group received broad-spectrum antibiotic therapy and peritoneal lavage. The combined therapy group received causal therapy plus supportive hemodynamic therapy. RESULTS: The sham animals showed no signs of systemic infection, while all other animals developed septic shock with arterial hypotension and lactic acidosis within 4.0 (4.0-6.8) hours. Induction of causal therapy did not impact on haemodynamics as compared to the control group. Notably, 50% of the control animals and none of the causal therapy animals survived the study. Combined therapy stabilized haemodynamics and improved organ function and survival as compared to control and causal therapy groups. CONCLUSIONS: The present data suggest that sole causal sepsis therapy without hemodynamic support worsens outcome even more than natural evolution of sepsis and combined causal and supportive therapy. This underlines the importance of early hemodynamic stabilization in parallel with antibiotic and surgical treatment of the sepsis focus.

A new complimentary web-based tool for manual analysis of microcirculation videos: Validation of the Capillary Mapper against the current gold standard AVA 3.2.

OBJECTIVE: The aim of the current study was to compare a newly developed web-based freely accessible software program for manual analysis of the microcirculation, the Capillary Mapper (CM), with AVA 3.2 software (AVA; MicroVision Medical B.V., Amsterdam, The Netherlands), which is the current gold standard for analysis of microcirculation videos. METHODS: A web-based software program was developed, which enables manual analysis of videos of the microcirculation to be carried out according to recommendations of the 2018 consensus conference. A set of 50 high quality microcirculation videos was analyzed with AVA and CM with respect to total vessel density, perfused vessel density, proportion of perfused vessels, and the microvascular flow index. RESULTS: Comparison of the mean values derived from manual analysis with CM and AVA revealed no significant differences in microcirculatory variables. Analysis according to Bland and Altman revealed an acceptable bias between manual analysis with the CM and AVA for all variables tested with sufficient limits of agreement. The analysis of intraclass correlation showed "excellent" agreement for all microcirculatory variables analyzed. CONCLUSIONS: The newly developed CM was successfully validated for manual analyses of microcirculation videos against the current gold standard, the software AVA 3.2.