Bacteria use diverse strategies and molecular machinery to maintain copper homeostasis and to cope with its toxic effects. Some genetic elements providing copper resistance are acquired by horizontal ...gene transfer; however, little is known about how they are controlled and integrated into the central regulatory network. Here, we studied two copper-responsive systems in a clinical isolate of Pseudomonas paraeruginosa and deciphered the regulatory and cross-regulation mechanisms. To do so, we combined mutagenesis, transcriptional fusion analyses and copper sensitivity phenotypes. Our results showed that the accessory CusRS two-component system (TCS) responds to copper and activates both its own expression and that of the adjacent nine-gene operon (the pcoA2 operon) to provide resistance to elevated levels of extracellular copper. The same locus was also found to be regulated by two core-genome-encoded TCSs-the copper-responsive CopRS and the zinc-responsive CzcRS. Although the target palindromic sequence-ATTCATnnATGTAAT-is the same for the three response regulators, transcriptional outcomes differ. Thus, depending on the operon/regulator pair, binding can result in different activation levels (from none to high), with the systems demonstrating considerable plasticity. Unexpectedly, although the classical CusRS and the noncanonical CopRS TCSs rely on distinct signaling mechanisms (kinase-based vs. phosphatase-based), we discovered cross-talk in the absence of the cognate sensory kinases. This cross-talk occurred between the proteins of these two otherwise independent systems. The cusRS-pcoA2 locus is part of an Integrative and Conjugative Element and was found in other Pseudomonas strains where its expression could provide copper resistance under appropriate conditions. The results presented here illustrate how acquired genetic elements can become part of endogenous regulatory networks, providing a physiological advantage. They also highlight the potential for broader effects of accessory regulatory proteins through interference with core regulatory proteins.
Today, the freight forwarder status raises some legal classification troubles. While some still attach it to the figure of the mandate, others insist on the contrary on its own particularities. These ...uncertainties seem to have been a difficulty for all the authors who wrote about this notion since the 16th century. Therefore, the examination of this long doctrinal controversy intends to shed light on the cause of this persistent disagreement.
Fish reproductive patterns are very diverse in terms of breeding frequency, mating system, sexual dimorphisms and selection, mate choice, spawning site choice, courtship patterns, spawning behaviors ...and parental care. Here we have compared the breeding behavior of the surface-dwelling and cave-dwelling morphs of the characiform A. mexicanus, with the goals of documenting the spawning behavior in this emerging model organism, its possible evolution after cave colonization, and the sensory modalities involved. Using infrared video recordings, we showed that cave and surface Astyanax spawning behavior is identical, occurs in the dark, and can be divided into 5 rapid phases repeated many times, about once per minute, during spawning sessions which last about one hour and involve one female and several males. Such features may constitute "pre-adaptive traits" which have facilitated fish survival after cave colonization, and may also explain how the two morphs can hybridize in the wild and in the laboratory. Accordingly, cross-breeding experiments involving females of one morphotype and males of the other morphotype showed the same behavior including the same five phases. However, breeding between cavefish females and surface fish males was more frequent than the reverse. Finally, cavefish female pheromonal solution was able to trigger strong behavioral responses in cavefish males-but not on surface fish males. Lastly, egg production seemed higher in surface fish females than in cavefish females. These results are discussed with regards to the sensory modalities involved in triggering reproductive behavior in the two morphs, as well as its possible ongoing evolution.
Epidemiological studies demonstrate that inherited factors play a major role in the development and prognosis of sepsis. However, genetic association studies in sepsis have produced contradictory ...evidence of an effect from individual polymorphisms. Major methodological flaws have been reported in a number of genetic association studies in non-septic populations, relating to problems with experimental design, statistical analysis, study size, power and replication. We hypothesised that genetic association studies investigating sepsis suffer from similar problems, and that this explains the lack of consistent evidence for an effect from polymorphisms.
A systematic review was conducted of published genetic association studies in sepsis from 1996-2005 using a newly devised scoring system for study quality and rigour. A Bayesian statistical analysis was also carried out to assess the false-positive report probability of identified studies.
Study quality was assessed using a 10-point scoring system designed from published reporting guidelines. The majority of studies were of low to intermediate quality, with deficiencies in control group selection, genetic assay technique, study blinding, statistical interpretation, study replication, study size and power. Bayesian analysis indicated that many of the studies reporting a positive association between a genetic polymorphism and sepsis were likely to represent false-positive associations.
The quality and size of genetic association studies in septic patients needs to improve if advances in identifying genetic effects in sepsis are to occur. Investigators should, as a minimum, follow recommended guidelines when designing studies.
The 2021 summer upwelling season off the United States Pacific Northwest coast was unusually strong leading to widespread near-bottom, low-oxygen waters. During summer 2021, an unprecedented number ...of ship- and underwater glider-based measurements of dissolved oxygen were made in this region. Near-bottom hypoxia, that is dissolved oxygen less than 61 µmol kg
and harmful to marine animals, was observed over nearly half of the continental shelf inshore of the 200-m isobath, covering 15,500 square kilometers. A mid-shelf ribbon with near-bottom, dissolved oxygen less than 50 µmol kg
extended for 450 km off north-central Oregon and Washington. Spatial patterns in near-bottom oxygen are related to the continental shelf width and other features of the region. Maps of near-bottom oxygen since 1950 show a consistent trend toward lower oxygen levels over time. The fraction of near-bottom water inshore of the 200-m isobath that is hypoxic on average during the summer upwelling season increases over time from nearly absent (2%) in 1950-1980, to 24% in 2009-2018, compared with 56% during the anomalously strong upwelling conditions in 2021. Widespread and increasing near-bottom hypoxia is consistent with increased upwelling-favorable wind forcing under climate change.
Background: The value of the phase angle (PhA), measured via bioelectrical impedance analysis (BIA), could be considered a good marker of the cell mass and the cell damage of a patient; however, ...there are new techniques, such as muscle ultrasonography, that allow the quantity and quality of muscle to be assessed in a minimally invasive way. The aim of this study is to determine the prognostic value of morphofunctional techniques in the prognosis of mortality in patients with idiopathic pulmonary fibrosis (IPF). Methods: This multicenter, cross-sectional study included 86 patients with idiopathic pulmonary fibrosis with a mean age of 71 years, 82.7% of whom were male. The nutritional risk of the patients was assessed by means of questionnaires, such as the Subjective Global Assessment (SGA), and non-invasive functional techniques, including BIA, nutritional ultrasound, and hand grip strength (HGS). Statistical analysis of the sample was performed using JAMOVI version 2.3.22. Results: Correlations were made between the RF-CSA techniques with PhA (r = 0.48, p < 0.001), BCM (r = 0.70, p < 0.001), SMI (r = 0.64, p < 0.001), and HGS (r = 0.54, p < 0.001). The cut-off points for 12-month mortality were PhA = 4.5° (AUC = 0.722, sensitivity of 72.7% and specificity of 66.6%), BCM = 28.8 kg (AUC = 0.609, sensitivity of 32.4% and specificity of 100.0%), RF-CSA = 3.00 cm2 (AUC = 0.857, sensitivity of 64.4% and specificity of 100.0%), 6MMW = 420 m (AUC = 0.830, sensitivity of 63.27% and specificity of 100.0%), and TUG = 7.2 s (AUC = 0.771, sensitivity of 100.0% and specificity of 56.67%). In addition, a multivariate analysis was performed with RF-CSA, HR = 8.11 (1.39–47.16, p = 0.020), and PhA of 6.35 (1.29–31.15, p = 0.023), taking into account age, sex, and BMI to determine mortality. Finally, a Kaplan–Meier survival analysis was conducted with low or normal values for classical parameters (GAP and T6MM) and new parameters (PhA, BCM, RF-CSA, and TUG). Conclusion: RF-CSA and PhA were shown to be good prognostic markers of 12-month mortality and could, therefore, be useful screening tools to complement the nutritional assessment of IPF patients.
Various ocean‐climate models driven by increased greenhouse gases and higher temperatures predict a decline in oceanic dissolved oxygen (DO) as a result of greater stratification, reduced ventilation ...below the thermocline, and decreased solubility at higher temperatures. Since spreading of low oxygen waters is underway and predicted to increase, understanding impacts on higher trophic levels is essential. Within the California Current System, shoaling of the oxygen minimum zone (OMZ) is expected to produce complex changes. Onshore movement of the OMZ could lead to habitat compression for species with higher oxygen requirements while allowing expansion of species tolerant of low bottom DO. As part of annual groundfish surveys, we sampled catch across a range of conditions from the upper to the lower limit of the OMZ and shoreward across the continental shelf of the US west coast. DO ranged from 0.02 to 4.25 mL L−1 with 642 stations (of 1020 sampled) experiencing hypoxic conditions in 2008–2010. Catch and species richness exhibited significant and positive relationships with near‐bottom oxygen concentration. The probability of occurrence was estimated for four species (spotted ratfish, petrale sole, greenstriped rockfish and Dover sole) using a binomial Generalized Additive Model. The models for each species included terms for position, day of the year, salinity, near‐bottom temperature and the interaction term between depth and near‐bottom DO. Spotted ratfish and petrale sole were sensitive to changes in near‐bottom oxygen, while greenstriped rockfish and Dover sole show no changes in probability of occurrence in relation to changes in oxygen concentration.
Life in the darkness of caves is accompanied, throughout phyla, by striking phenotypic changes including the loss or severe reduction in eyes and pigmentation. On the other hand, cave animals have ...undergone constructive changes, thought to be adaptive, to survive in this extreme environment. The present study addresses the question of the evolution of growth in caves, taking advantage of the comparison between the river-dwelling and the cave-dwelling morphs of the Mexican tetra,
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A sclerochronology approach was undertaken to document the growth of the species in these two very distinct habitats. Scales from 158 wild
specimens were analyzed from three caves (Pachón, Tinaja and Subterráneo) and two rivers (Rio Gallinas and Arroyo Lagarto) in San Luis Potosi and Tamaulipas, Mexico. A 10-13% reduction in scales size was observed in the cave morphs compared to the surface morphs. Age could be reliably inferred from annual growth increments on the scales from the two morphs of the species. Further comparisons with growth curves in laboratory conditions, obtained using the von Bertalanffy growth model, were also performed. In the wild and in the laboratory, cavefish originating from the Pachón cave reached smaller sizes than surface fish from three different locations: Rio Gallinas and Arroyo Lagarto (wild sampling) and Texas (laboratory population), respectively. Wild Pachón cavefish also seemed to grow to smaller sizes than the two other wild cavefish populations studied, Tinaja and Subterráneo. Finally, growth in the laboratory was faster than in the wild, particularly in the two first years of life.
These data suggest that cavefish originating from the Pachón cave are subjected to an intrinsic limitation of their final size, which is at least in part independent from energy/food availability. This growth limitation may be an advantageous way of limiting energy expenditure and food needs in the cave environment. Moreover, growth regulation evolved differently in independently evolved cave populations. These results are discussed with regard to the sources of energy or general ecological conditions present in caves, and to the differences in behavior or feeding skills known in cavefish.
The morphogenesis of the vertebrate eye consists of a complex choreography of cell movements, tightly coupled to axial regionalization and cell type specification processes. Disturbances in these ...events can lead to developmental defects and blindness. Here, we have deciphered the sequence of defective events leading to coloboma in the embryonic eye of the blind cavefish of the species Astyanax mexicanus. Using comparative live imaging on targeted enhancer-trap Zic1:hsp70:GFP reporter lines of both the normal, river-dwelling morph and the cave morph of the species, we identified defects in migratory cell behaviours during evagination that participate in the reduced optic vesicle size in cavefish, without proliferation defect. Further, impaired optic cup invagination shifts the relative position of the lens and contributes to coloboma in cavefish. Based on these results, we propose a developmental scenario to explain the cavefish phenotype and discuss developmental constraints to morphological evolution. The cavefish eye appears as an outstanding natural mutant model to study molecular and cellular processes involved in optic region morphogenesis.
Flatfish condition indices and distribution were examined along the U.S. west coast (55–1280m) in relation to environmental variability and biomass using data from ten frequently occurring species ...collected in annual groundfish surveys from 2003 to 2010. The study was conducted during a period characterized by a cooling trend in the northern California Current system and by declining biomass for flatfish in general. Annual condition indices for six species (arrowtooth flounder, Dover sole, English sole, Pacific sanddab, petrale sole, and rex sole) were significantly related either to large-scale climatic indices (Pacific Decadal Oscillation, Multivariate El Niño–Southern Oscillation Index, North Pacific Gyre Oscillation) and/or annual biomass levels. Condition was most closely related to environmental effects rather than either biomass alone or both variables, with condition typically higher during cool climatic conditions. A similar analysis revealed that changes in distribution (measured as variation in annual catch-weighted mean latitude, longitude, depth and temperature) tended to be best described by models incorporating environmental effects and biomass rather than either variable alone. Linear trends in the center of distribution along a southeast–northwest axis were significant for seven species (arrowtooth flounder, deepsea sole, Dover sole, flathead sole, Pacific sanddab, petrale sole, and slender sole) with a tendency for flatfish to be displaced towards the southeast as environmental conditions shifted from warm to cooler conditions and biomass declined. A spatial distribution analysis indicated that for the majority of species (80%) the greatest magnitude of displacement (km) occurred when the centers of biomass were compared between environmental phases (average annual displacement 34km) rather than changing biomass levels (average displacement 24km). Taken together both approaches revealed that environmental changes and variation in biomass play significant roles in flatfish distribution.
•We examined condition and distribution of ten flatfish species along the U.S. west coast.•Both were compared with large-scale environmental indices and fluctuating biomass levels.•Based on AIC, condition was most closely related to environmental effects rather than biomass.•Distributional shifts were usually best described by models with environmental effects and biomass.•Flatfish were generally displaced southeast as conditions cooled and biomass declined.
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