Technical success, procedural safety, and efficacy of the Silk Vista Baby in the treatment of cerebral aneurysms over a mid-to-long-term follow-up.

Background: Long-term follow-up of cerebral aneurysms treated with the Silk Vista Baby (SVB) flow diverter is lacking. This study aimed to assess the technical success, procedural safety, and efficacy of the SVB (Balt, Montmorency, France) for the treatment of intracranial aneurysms in small cerebral vessels over a mid-to long-term follow-up. Methods: We retrospectively analyzed a prospectively maintained database of patients treated with the SVB between September 2018 and June 2021. Data regarding patient demographics, aneurysm characteristics, and technical procedures were also collected. Angiographic and clinical findings were recorded during the procedure and over a period of at least 12 months. Results: Angiographic and clinical follow-up data were available for 50 patients/50 aneurysms. The procedural complication rate was 8%. At 12 months, the final results showed a technical success rate of 100%, the re rupture rate was 0%, neuromorbidity and mortality rates of 4 and 0%, respectively, and an almost complete occlusion rate of 94%. Conclusion: Treatment of complex intracranial aneurysms with the SVB was safe and effective. Long-term results showed high rates of adequate and stable occlusions.

No evidence for association between rs10191329 severity locus and longitudinal disease severity in 1813 relapse-onset multiple sclerosis patients from the MSBase registry.

BACKGROUND: The International Multiple Sclerosis Genetics Consortium and MultipleMS Consortium recently reported a genetic variant associated with multiple sclerosis (MS) severity. However, it remains unclear if these variants remain associated with more robust, longitudinal measures of disease severity. METHODS: We examined the top variant, rs10191329, from Harroud et al.'s study in 1813 relapse-onset MS patients from the MSBase Registry to assess association with longitudinal disease severity. RESULTS: Our analysis revealed no significant association between rs10191329 genotype and longitudinal binary disease severity (p > 0.05). CONCLUSION: These findings highlight the complexity of genetic factors mediating long-term MS outcomes and the need for further research.

Prognostic effect of systematic geriatric assessment on patients with acute heart failure.

AIMS: Frailty and dependence are frequent in patients admitted for acute heart failure (AHF), but their prognostic significance is unknown, especially in young adults. We aimed to study in adults admitted for AHF, regardless of age, the effect of frailty and dependence on the incidence of mortality and a combined event of mortality, readmissions for AHF, and visits to the emergency room (ER) for AHF at 1 and 6 months. METHODS AND RESULTS: We designed a prospective cohort study by including all the patients with AHF admitted in our Cardiology Department from July 2020 through May 2021. A multidimensional geriatric assessment was performed during the admission. We clinically followed up the patients 6 months after discharge. We enrolled 202 patients. The mean age was 73 ± 12.32 years, and 100 (49.5%) of the patients were elderly (>75 years). Just 78 patients (38.6%) were women, and 100 (49.5%) had previous HF. Frailty (FRAIL ≥ 3) was observed in 68 (33.7%) patients (mean FRAIL score: 1.88 ± 1.48). Dependence (Barthel < 100) was observed in 65 (32.2%) patients (mean Barthel index: 94.38 ± 11.21). Frailty and dependence showed a significant association with both prognostic events at 1 and 6 months. In the multivariable analysis, frailty was associated with higher mortality at 1 month [hazard ratio (HR) 12.61, 95% confidence interval (CI) 1.57-101.47, P = 0.017] but not at 6 months (HR 2.25, 95% CI 0.61-8.26, P = 0.224) or with the combined endpoint at neither 1 month (HR 1.64, 95% CI 0.54-5.03, P = 0.384) nor 6 months (HR 1.35, 95% CI 0.75-2.46, P = 0.320). Dependence was related to higher mortality at 1 month (HR 13.04, 95% CI 1.62-104.75, P = 0.016) and 6 months (HR 7.18, 95% CI 1.99-25.86, P = 0.003) and to higher incidence of the combined event at 1 month (HR 5.93, 95% CI 1.63-21.50, P = 0.007) and 6 months (HR 2.62, 95% CI 1.49-4.61, P = 0.001). CONCLUSIONS: In AHF patients, frailty and dependence implied a worse prognosis, rising mortality, readmissions, and ER visits for AHF.

Temporal and spatial variability in population traits of an intertidal fucoid reveals local-scale climatic refugia.

Global change is imposing significant losses in the functional traits of marine organisms. Although areas of climatic refugia ameliorate local conditions and help them to persist, the extent to which mesoscale effects contribute for intraregional variability on population traits and conservation is uncertain. Here we assess patterns of conservation status of Fucus guiryi, the main intertidal habitat-forming seaweed in the Strait of Gibraltar (southern Spain and northern Morocco). We investigated the demography, reproductive phenology, and morphology at northern and southern side populations. Population traits were compared seasonally within populations from each side, and at spatial scale in early summer 2019. In the last decade three populations became extinct; two marginal populations had dispersed individuals with a narrower fertility season and miniaturized individuals below 3 cm; and five populations showed variable density and cover with more than 20% of reproductive individuals over the seasons. Highest density, cover, morphology, and reproductive potential was detected at one population from each side, suggesting local-scale climatic refugia in upwelling areas located inside marine protected areas. Southern recruits were more warm-tolerant but grew less at colder conditions than northern ones, revealing a mesoscale heterogeneity in thermal affinities. This study evidenced functional losses and distinct reproductive strategies experienced by F. guiryi at peripheral locations and urges to prioritize its conservation and restoration at contemporary climatic refugia.

Fast systematic geriatric assessment in acute heart failure patients admitted in Cardiology.

BACKGROUND: Heart failure prevalence is increasing in elder adults. These patients usually present geriatric syndromes, especially frailty. The effect of frailty on heart failure is under discussion but there are few data about the clinical characterization of frail patients who are admitted for acute heart failure decompensation. OBJECTIVE: The purpose of this study was to study the differences in clinical baseline variables and geriatric scales between frail and non-frail patients admitted to the Cardiology unit via the Emergency Department for acute heart failure. METHODS: We enrolled all patients with acute heart failure who were admitted to the Cardiology unit from the Emergency Department of our hospital from July 2020 through May 2021. A multidimensional and comprehensive geriatric assessment was performed at the moment of admission. We studied differences in baseline variables and geriatric scales according to the frailty status determined by the FRAIL scale. RESULTS: A total of 202 patients were included. In the whole population, 68 (33.7%) patients presented frailty defined by a FRAIL score ≥ 3. The frail patients were older (80±9 vs. 69±12 years; p<0.001), and had a worse quality of life (58.31±12.18 vs.39.26±13.71 points; p<0.001) according to the Minnesota scale, presented high comorbidity (47 (69.1%) vs. 67 (50.4%) patients; p = 0.011) defined as ≥3 points according to the Charlson scale and were more dependent (40 (58.8%) vs. 25 (18.8%) patients; p<0.001) according to the Barthel scale. The frail patients presented higher MAGGIC risk scores (24.09±4.99 vs. 18.89±6.26; p<0.001). Despite this adverse profile, the treatments prescribed during the admission and at the hospital discharge were similar. CONCLUSIONS: The prevalence of geriatric syndromes, especially frailty, is very high in patients admitted for acute heart failure. Frail patients with acute heart failure had an adverse clinical profile with more prevalence of concomitant geriatric syndromes. Therefore, we consider that a geriatric assessment should be performed during the admission of acute heart failure patients to improve care and attention.

Association of Serum Neurofilament Light Chain Levels at Disease Onset With Disability Worsening in Patients With a First Demyelinating Multiple Sclerosis Event Not Treated With High-Efficacy Drugs.

Importance: The value of serum neurofilament light chain (sNfL) levels for predicting long-term disability in patients with multiple sclerosis (MS) remains controversial. Objective: To assess whether high sNfL values are associated with disability worsening in patients who underwent their first demyelinating MS event. Design, Setting, and Participants: This multicenter cohort study included patients who underwent their first demyelinating event suggestive of MS at Hospital Universitario Ramón y Cajal (development cohort; June 1, 1994, to September 31, 2021, with follow-up until August 31, 2022) and 8 Spanish hospitals (validation cohort; October 1, 1995, to August 4, 2020, with follow-up until August 16, 2022). Exposures: Clinical evaluations at least every 6 months. Main Outcomes and Measures: The main outcomes were 6-month confirmed disability worsening (CDW) and an Expanded Disability Status Scale (EDSS) score of 3. Levels of sNfL were measured in blood samples obtained within 12 months after disease onset using a single molecule array kit. The cutoffs used were sNfL level of 10 pg/mL and a standardized score (z score) of 1.5. Multivariable Cox proportional hazards regression models were used to evaluate outcomes. Results: Of the 578 patients included in the study, 327 were in the development cohort (median age at sNfL analysis, 34.1 years [IQR, 27.2-42.7 years]; 226 female [69.1%]) and 251 patients were in the validation cohort (median age at sNfL analysis, 33.3 years [IQR, 27.4-41.5 years]; 184 female [73.3%]). The median follow-up was 7.10 years (IQR, 4.18-10.0 years). Levels of sNfL greater than 10 pg/mL were independently associated with higher risk of 6-month CDW and an EDSS of 3 in the development cohort (6-month CDW: hazard ratio [HR], 2.39; 95% CI, 1.39-4.12; P = .002; EDSS of 3: HR, 4.12; 95% CI, 2.18-7.77; P < .001) and the validation cohort (6-month CDW: HR, 1.61; 95% CI, 1.07-2.42; P = .02; EDSS of 3: HR, 2.03; 95% CI, 1.23-3.33; P = .005). Highly effective disease-modifying treatments were associated with lower risks of 6-month CDW and an EDSS of 3 in patients with high baseline sNfL values. Conclusions and Relevance: This cohort study found that high sNfL values obtained within the first year of disease were associated with long-term disability worsening in MS, suggesting that sNfL level measurement may help identify optimal candidates for highly effective disease-modifying treatments.

Implementación de talleres de autocuidado en pacientes con amputación de miembros inferiores debida a diabetes / Implementation of self-care workshops in patients with lower limb amputation due to diabetes

INTRODUCCIÓN: Con frecuencia, los pacientes con amputación asociada a diabetes mellitus tipo 2 o patologías cardiovasculares presentan dificultades en la adherencia al cumplimiento de cuidados necesarios. El objetivo general de esta intervención sanitaria fue facilitar información sobre el abordaje integral que requiere el paciente con diagnóstico de amputación secundaria a diabetes o vascular para fomentar el autocuidado, potenciar la adquisición de nuevos hábitos saludables y mejorar la calidad de vida. MÉTODOS: Se desarrolló un taller para promover el autocuidado, dirigido a pacientes ambulatorios y coordinado por todos los profesionales del equipo tratante. Consistió en siete encuentros semanales de una hora y media cada uno. Hubo una evaluación previa y una encuesta al final con los ítems de autocuidado. RESULTADOS: En la experiencia de taller de autocuidado participaron 24 sujetos. En la evaluación previa a los talleres, el 94% de los participantes afirmaron conocer los cuidados necesarios para su condición de salud. Se observó un bajo grado de adherencia en los indicadores de dieta balanceada, realización de actividad física y cuidado de la piel de pies. La encuesta final mostró una mejor adherencia a las indicaciones de autocuidado. DISCUSIÓN: La implementación de un taller de autocuidado por el equipo interdisciplinario tratante favoreció la incorporación de pautas de cuidado de la propia salud, de alarma y de necesidad de abordaje terapéutico.

Multifaceted Analysis of Cerebrospinal Fluid and Serum from Progressive Multiple Sclerosis Patients: Potential Role of Vitamin C and Metal Ion Imbalance in the Divergence of Primary Progressive Multiple Sclerosis and Secondary Progressive Multiple Sclerosis.

The progressive forms of multiple sclerosis (MS) primary progressive MS (PPMS) and secondary progressive MS (SPMS) are clinically distinguished by the rate at which symptoms worsen. Little is however known about the pathological mechanisms underlying the differential rate of accumulation of pathological changes. In this study, 1H NMR spectroscopy was used to measure low-molecular-weight metabolites in paired cerebrospinal fluid (CSF) and serum of PPMS, SPMS, and control patients, as well as to determine lipoproteins and glycoproteins in serum samples. Additionally, neurodegenerative and inflammatory markers, neurofilament light (NFL) and chitinase-3-like protein 1 (CHI3L1), and the concentration of seven metal elements, Mg, Mn, Cu, Fe, Pb, Zn, and Ca, were also determined in both CSF and serum. The results indicate that the pathological changes associated with progressive MS are mainly localized in the central nervous system (CNS). More so, PPMS and SPMS patients with comparable disability status are pathologically similar in relation to neurodegeneration, neuroinflammation, and some metabolites that distinguish them from controls. However, the rapid progression of PPMS from the onset may be driven by a combination of neurotoxicity induced by heavy metals coupled with diminished CNS antioxidative capacity associated with differential intrathecal ascorbate retention and imbalance of Mg and Cu.

Not all roads lead to the immune system: the genetic basis of multiple sclerosis severity.

Multiple sclerosis is a leading cause of neurological disability in adults. Heterogeneity in multiple sclerosis clinical presentation has posed a major challenge for identifying genetic variants associated with disease outcomes. To overcome this challenge, we used prospectively ascertained clinical outcomes data from the largest international multiple sclerosis registry, MSBase. We assembled a cohort of deeply phenotyped individuals of European ancestry with relapse-onset multiple sclerosis. We used unbiased genome-wide association study and machine learning approaches to assess the genetic contribution to longitudinally defined multiple sclerosis severity phenotypes in 1813 individuals. Our primary analyses did not identify any genetic variants of moderate to large effect sizes that met genome-wide significance thresholds. The strongest signal was associated with rs7289446 (ß = -0.4882, P = 2.73 × 10-7), intronic to SEZ6L on chromosome 22. However, we demonstrate that clinical outcomes in relapse-onset multiple sclerosis are associated with multiple genetic loci of small effect sizes. Using a machine learning approach incorporating over 62 000 variants together with clinical and demographic variables available at multiple sclerosis disease onset, we could predict severity with an area under the receiver operator curve of 0.84 (95% CI 0.79-0.88). Our machine learning algorithm achieved positive predictive value for outcome assignation of 80% and negative predictive value of 88%. This outperformed our machine learning algorithm that contained clinical and demographic variables alone (area under the receiver operator curve 0.54, 95% CI 0.48-0.60). Secondary, sex-stratified analyses identified two genetic loci that met genome-wide significance thresholds. One in females (rs10967273; ßfemale = 0.8289, P = 3.52 × 10-8), the other in males (rs698805; ßmale = -1.5395, P = 4.35 × 10-8), providing some evidence for sex dimorphism in multiple sclerosis severity. Tissue enrichment and pathway analyses identified an overrepresentation of genes expressed in CNS compartments generally, and specifically in the cerebellum (P = 0.023). These involved mitochondrial function, synaptic plasticity, oligodendroglial biology, cellular senescence, calcium and G-protein receptor signalling pathways. We further identified six variants with strong evidence for regulating clinical outcomes, the strongest signal again intronic to SEZ6L (adjusted hazard ratio 0.72, P = 4.85 × 10-4). Here we report a milestone in our progress towards understanding the clinical heterogeneity of multiple sclerosis outcomes, implicating functionally distinct mechanisms to multiple sclerosis risk. Importantly, we demonstrate that machine learning using common single nucleotide variant clusters, together with clinical variables readily available at diagnosis can improve prognostic capabilities at diagnosis, and with further validation has the potential to translate to meaningful clinical practice change.

Colon necrosis in acute severe pancreatitis.

A 78 year-old woman was admitted for biliary acute pancreatitis (AP). Fluid and analgesia were initially administered. Her clinical course was poor with persisting abdominal pain, intestinal paresis and fever development. On her 7th admission day a contrast-enhanced computed tomography scan was performed where a huge necrotic peripancreatic collection was found with gastric compression .

Rehabilitación pulmonar en pacientes con diagnóstico de fibrosis quística / Pulmonary rehabilitation in patients diagnosed with cystic fibrosis

La fibrosis quística (FQ) es una enfermedad genética que se hereda de forma autosómica recesiva, tiene características multiorgánicas y se presenta con mayor frecuencia en población caucásica. La disfunción respiratoria es la causa de muerte en cerca del 95% de los pacientes con FQ y una causa importante de morbilidad. Los programas de rehabilitación pulmonar en casos de FQ deben centrarse en las necesidades específicas de cada paciente, mejorar su tolerancia al ejercicio y su movilización de secreciones, disminuir el riesgo de complicaciones e impactar en su calidad de vida.

Cystic fibrosis (CF) is a genetic disease inherited in an autosomal recessive manner; it has multi-organ characteristics and occurs more frequently in the Caucasian population. Respiratory dysfunction is the cause of death in about 95% of CF patients and a major cause of morbidity. Pulmonary rehabilitation programs in CF cases should focus on each patient's specific needs, improve their exercise tolerance and mobilization of secretions, decrease the risk of complications, and impact their quality of life.

High prevalence of intrathecal IgA synthesis in multiple sclerosis patients.

The detection of intrathecal IgA synthesis (IAS) in multiple sclerosis (MS) could be underestimated. To assess it, we develop a highly sensitive assay based on isoelectric focusing (IEF). 151 MS patients and 53 controls with different neurological diseases were recruited. IgA concentration was analyzed using a newly developed in house ELISA. IgA oligoclonal bands to detect IAS were determined by IEF. Most individuals showed an IgA concentration within normal range in serum samples (90.69%) but 31.37% of individuals had a IgA concentration below the normal range in the cerebrospinal fluid (CSF). No significant differences were observed between MS and control groups, neither in CSF nor in serum. The new IEF was more sensitive than those previously described (0.01 mg/dl of IgA), and clearly identified patients with and without IAS, that was not related with IgA concentration. Using IEF, MS patients showed higher percentage of IAS-IEF (43.00%) than the control group (16.98) (p = 0.001). The incidence was especially higher in patients with clinically isolated syndrome (66.00%). The new IFE demonstrated a higher percentage of IAS in MS patients than assumed in the past. The presence of IAS-IEF in MS is higher than in other neurological diseases.

Differences According to Age in the Diagnostic Performance of Cardiac Biomarkers to Predict Frailty in Patients with Acute Heart Failure.

Frailty has traditionally been studied in the elderly population but scarcely in younger individuals. The objective of the present study is to analyze differences according to age in the diagnostic performance of cardiac biomarkers to predict frailty in patients admitted to the hospital for acute heart failure (AHF). A frailty assessment was performed with the SPPB and FRAIL scales (score > 3). We included 201 patients who were divided according to age: those older and younger than 75 years. In the younger group, no biomarker was related to the presence of frailty. This was mainly determined by age and comorbidities. In the elderly group, NT-proBNP was significantly related to the presence of frailty, but none of the baseline characteristics were. The best cut-off point in the elderly group for NT-proBNP was 4000 pg/mL. The area under the curve (AUC) for proBNP for frailty detection was 0.62 in the elderly. Another similar frailty scale, the SPPB, also showed a similar AUC in this group; however, adding the NT-proBNP (one point if NT-proBNP < 4000 pg/mL), it showed a slightly higher yield (AUC 0.65). The addition of biomarkers could improve frailty detection in members of the elderly population who are admitted to the hospital for AHF.

Identification of the genetic mechanism that associates L3MBTL3 to multiple sclerosis.

Multiple sclerosis (MS) is a complex and demyelinating disease of the central nervous system. One of the challenges of the post-genome-wide association studies (GWAS) era is to understand the molecular basis of statistical associations to reveal gene networks and potential therapeutic targets. The L3MBTL3 locus has been associated with MS risk by GWAS. To identify the causal variant of the locus, we performed fine mapping in a cohort of 3440 MS patients and 1688 healthy controls. The variant that best explained the association was rs6569648 (P = 4.13E-10, odds ratio = 0.71, 95% confidence interval (CI) = 0.64-0.79), which tagged rs7740107, located in intron 7 of L3MBTL3. The rs7740107 (A/T) variant has been reported to be the best expression and splice quantitative trait locus (eQTL and sQTL) of the region in up to 35 human genotype-tissue expression (GTEx) tissues. By sequencing RNA from blood of 17 MS patients and quantification by digital qPCR, we determined that this eQTL/sQTL originated from the expression of a novel short transcript starting in intron 7 near rs7740107. The short transcript was translated into three proteins starting at different translation initiation codons. These N-terminal truncated proteins lacked the region where L3MBTL3 interacts with the transcriptional regulator Recombination Signal Binding Protein for Immunoglobulin Kappa J Region which, in turn, regulates the Notch signalling pathway. Our data and other functional studies suggest that the genetic mechanism underlying the MS association of rs7740107 affects not only the expression of L3MBTL3 isoforms, but might also involve the Notch signalling pathway.

Changes in the growth rate of Chlamydomonas reinhardtii under long-term selection by temperature and salinity: Acclimation vs. evolution.

We investigated the roles of acclimation and different components involved in evolution (adaptation, chance and history) on the changes in the growth rate of the model freshwater microalga Chlamydomonas reinhardtii P. A. Dang. exposed to selective temperature and salinity. Three C. reinhardtii strains previously grown during one year in freshwater medium and 20 °C were exposed to 5 °C temperature increase and a salinity of 5 g L-1 NaCl. Cultures under each selective scenario and in combination (increase of salinity and temperature), were propagated until growth rate achieved an invariant mean value for 6 months (100-350 generations, varying as a function of scenario and strain). The changes of the growth rate under increased temperature were due to both adaptation and acclimation, as well as history. However, acclimation was the only mechanism detected under salinity increase as well as in the selective scenario of both temperature and salinity, suggesting that genetic variability would not allow survival at salinity higher than that to which experimental populations were exposed. Therefore, it could be hypothesized that under a global change scenario an increase in salinity would be a greater challenge than warming for some freshwater phytoplankton.

Incidence, Clinical Presentation, Relapses and Outcome of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in Patients Treated With Anti-CD20 Monoclonal Antibodies.

BACKGROUND: Our objective is to describe the presentation and complications, including relapses, of coronavirus disease 2019 (COVID-19) in patients under anti-CD20 treatments. In addition, to describe viral clearance and determine the safety of reintroducing anti-CD20 treatment. METHODS: Retrospective cohort study of 422 patients under anti-CD20 treatment that was administered from 1 January 2019 to 31 December 2020. RESULTS: Fifty-seven patients were diagnosed with COVID-19 (13.5%). Twenty-five patients (43.9%) required hospital admission. Five patients died (8.8%), and 10 developed severe COVID-19 and acute respiratory distress syndrome. Mortality rate was higher among patients infected during the first 3 months following the last dose of anti-CD20 (14.7% vs 0%, P = .046). The median time of persistence of positive reverse transcription polymerase chain reaction (RT-PCR) was 22 days (IQR 13-40).Nine out of 52 survivors (17.3%) presented relapses. All of them received the last dose of anti-CD20 less than 6 months before the COVID-19 episode. Clinical presentation was fever (n = 8; 88.9%), dyspnea (n = 7; 77.8%), cough (n = 7; 77.8%), worsening of previous infiltrates (n = 5; 55.6%) and new pulmonary infiltrates (n = 8; 88.9%). An increase in lymphocytes with CD4/CD8 ratio inversion was observed in all cases. Among the 25 patients who resumed anti-CD20 drug, 4 (16.0%) presented relapses vs 5/28 among those who did not (17.9%), (P = .857). CONCLUSIONS: Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the 6 months after anti-CD20 administration had a worse outcome and a higher mortality rate. The duration of infectivity may be longer. Relapses of COVID-19 occurred in more than 15% and were associated with viral replication. Once the infection is resolved, it is safe to restart treatment with anti-CD20.

Photosynthetic performance in cyanobacteria with increased sulphide tolerance: an analysis comparing wild-type and experimentally derived strains.

Sulphide is proposed to have influenced the evolution of primary stages of oxygenic photosynthesis in cyanobacteria. However, sulphide is toxic to most of the species of this phylum, except for some sulphide-tolerant species showing various sulphide-resistance mechanisms. In a previous study, we found that this tolerance can be induced by environmental sulphidic conditions, in which two experimentally derived strains with an enhanced tolerance to sulphide were obtained from Microcystis aeruginosa, a sensitive species, and Oscillatoria, a sulphide-tolerant genus. We have now analysed the photosynthetic performance of the wild-type and derived strains in the presence of sulphide to shed light on the characteristics underlying the increased tolerance. We checked whether the sulphide tolerance was a result of higher PSII sulphide resistance and/or the induction of sulphide-dependent anoxygenic photosynthesis. We observed that growth, maximum quantum yield, maximum electron transport rate and photosynthetic efficiency in the presence of sulphide were less affected in the derived strains compared to their wild-type counterparts. Nevertheless, in 14C photoincoporation assays, neither Oscillatoria nor M. aeruginosa exhibited anoxygenic photosynthesis using sulphide as an electron donor. On the other hand, the content of photosynthetic pigments in the derived strains was different to that observed in the wild-type strains. Thus, an enhanced PSII sulphide resistance appears to be behind the increased sulphide tolerance displayed by the experimentally derived strains, as observed in most natural sulphide-tolerant cyanobacterial strains. However, other changes in the photosynthetic machinery cannot be excluded.

Detection of the maximum resistance to the herbicides diuron and glyphosate, and evaluation of its phenotypic cost, in freshwater phytoplankton.

One of the most important anthropogenic impacts on freshwater aquatic ecosystems close to intensive agriculture areas is the cumulative increase in herbicide concentrations. The threat is especially relevant for phytoplankton organisms because they have the same physiological targets as the plants for which herbicides have been designed. This led us to explore the evolutionary response of three phytoplanktonic species to increasing concentrations of two herbicides and its consequences in terms of growth and photosynthesis performance. Specifically, we used an experimental ratchet protocol to investigate the differential evolution and the limit of resistance of a cyanobacterium (Microcystis aeruginosa) and two chlorophyceans (Chlamydomonas reinhardtii and Dictyosphaerium chlorelloides) to two herbicides in worldwide use: glyphosate and diuron. Initially, the growth rate of M. aeruginosa and D. chlorelloides was completely inhibited when they were exposed to a dose of 0.23 ppm diuron or 40 ppm glyphosate, whereas a higher concentration of both herbicides (0.46 ppm diuron or 90 ppm glyphosate) was necessary to abolish C. reinhardtii growth. However, after running a ratchet protocol, the resistance of the three species to both herbicides increased by an adaptation process. M. aeruginosa and D. chlorelloides were able to grow at 1.84 ppm diuron and 80 ppm glyphosate and C. reinhardtii proliferated at twice these concentrations. Herbicide-resistant strains showed lower growth rates than their wild-type counterparts in the absence of herbicides, as well as changes on morphology and differences on photosynthetic pigment content. Besides, herbicide-resistant cells generally showed a lower photosynthetic performance than wild-type strains in the three species. These results indicate that the introduction of both herbicides in freshwater ecosystems could produce a diminution of primary production due to the selection of herbicide-resistant mutants, that would exhibit lower photosynthetic performance than wild-type populations.