Photosymbioses between marine cnidarians (e.g. sea anemones and corals) and Symbiodiniaceae dinoflagellates are influenced by abiotic factors like light and temperature. The anemone Exaiptasia diaphana is widely used as a model for understanding the Symbiodiniaceae-Cnidaria photosymbiotic system. Despite extensive research on many facets of this photosymbiosis, key photophysiological processes, such as photosystem II (PSII) photo-inactivation and repair mechanisms, remain poorly characterized. In this study, we used individuals of E. diaphana harbouring endosymbiotic dinoflagellates from the genus Breviolum to characterize the susceptibility to photoinactivation and repair capacity (measured by photoinactivation and repair rates, kPI and kREC, respectively) of PSII in the symbiont under thermal stress (16 degrees C and 32 degrees C) using in vivo imaging of chlorophyll fluorometry and lincomycin as a protein synthesis inhibitor. The results showed that the repair capacity of PSII of the symbionts (kREC) was higher than the susceptibility to photoinactivation (kPI) despite of the level of thermal stress applied. Elevated temperatures increased the vulnerability of PSII to damage and reduced its repair capacity. In contrast, cold stress decreased the susceptibility to PSII damage but considerably reduced the efficiency of repair mechanisms. Extreme temperatures affected both PSII repair capacity, decreasing kREC, and photo-inactivation, increasing kPI under high temperatures (greater susceptibility to photodamage) and decreasing kPI under low temperatures (lower susceptibility to photodamage). By characterizing the sensitivity of the E. diaphana-Breviolum photosymbioses to thermal stress, this study provides insights on the photophysiological vulnerability and resilience cnidarian-dinoflagellate in general, contributing to the understanding of the potential impacts of environmental change.

Diatoms inhabiting estuarine intertidal flats are regularly exposed to episodes of high irradiance and elevated temperature during daytime low tides, conditions prone to inducing strong photoinhibition of photosystem II (PSII). However, the extent to which different species cope with repeated exposure to these combined stressors, and how photoacclimation modulates these responses, remains poorly known. This study examined the interspecific diversity in PSII photoinactivation, photorepair and photoprotection of three estuarine pennate diatom species exposed to three consecutive daily periods of combined high light and heat: two benthic species, Navicula phyllepta and Entomoneis paludosa, and one tychoplanktonic species, Cylindrotheca closterium. Unialgal cultures of each species were also acclimated to contrasting low- (LL) and high-light (HL) regimes to further evaluate the influence of photoacclimation on the responses to light and heat stress. In the two benthic species, PSII photoinactivation was largely counterbalanced by efficient photorepair, leading to near-complete recovery after each stress event. In contrast, the tychoplanktonic C. closterium showed markedly higher photoinactivation rates and limited photorepair capacity, resulting in an overall poor recovery. The tested species also differed strongly in the operation of the xanthophyll cycle (XC). Although XC-mediated de-epoxidation of the pigment diadinoxanthin into diatoxanthin increased under stress in all LL-acclimated cultures, it was strongly reduced in the HL-acclimated benthic species. Despite pronounced short-term effects of each stress exposure, no significant accumulation of irreversible PSII damage occurred over the 3 days, likely due to extended recovery intervals that favored an effective PSII photorepair. Overall, the results show that species-specific physiological traits and photoacclimation state play a dominant role in determining the capacity of diatoms to cope with the extreme conditions found in the estuarine intertidal environments.

Pennate diatoms are photosynthetic microorganisms capable of directed motility in response to light. In sedimentary habitats, many epipelic pennate diatoms exhibit photophobic migration under high light, a behaviour critical for avoiding photodamage and key to ecological success. While the ecophysiological significance of this behaviour is well-documented, the mechanisms linking light sensing to motility remain poorly understood. This study investigated whether the transthylakoidal proton gradient (ΔpH), generated under high light, intervenes in the signal transduction mechanism driving photophobic migration. The impact of the ΔpH inhibitors Nigericin and Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) on the vertical migration of benthic pennate diatoms was monitored using non-destructive imaging chlorophyll fluorometry on intertidal diatom-dominated microphytobenthos biofilms. The results showed that ΔpH inhibition significantly reduced the downward, high light-avoiding, migratory response, supporting the hypothesis that ΔpH plays a central role in mediating this response. Additionally, results showed that the effective quantum yield of PSII and non-photochemical quenching (NPQ) were impacted by ΔpH inhibition with a dose-dependent effect. These findings strongly support ΔpH as an integrative signal linking physiological and behavioural photoprotection mechanisms and suggest that ΔpH may also modulate intracellular signalling, explaining the efficient capacity of pennate diatoms to cope with high light exposure in benthic habitats.

Pennate diatoms are an ecologically and evolutionarily successful group of algae, dominating in sedimentary habitats where they form biofilms with high productivity and diversity. Their success has been attributed to directed motility, which is used to explore the microscale environmental gradients present in sediments, particularly regarding light, optimizing photosynthesis while avoiding photodamage. Some pennate diatoms can exhibit a process termed karyostrophy, the contraction of the chloroplasts toward the cell center when exposed to high light. Karyostrophy has long been hypothesized to play a photoprotective role; however, its light dependency and physiological effects remain poorly characterized. This study investigated the light-dependent kinetics and photophysiological effects of karyostrophy in the diatom Pleurosigma strigosum. Chloroplast contraction was found to be light-dependent, being induced under irradiances above 60 μmol photons · m-2 · s-1, with the rate and extent of contraction increasing with light intensity. The process was reversible, with chloroplasts returning to their original conformation under low light, although at a slower rate. Cell-level photophysiological measurements indicated that karyostrophy enhanced self-shading in proximal cell regions, improving the capacity of the cells to recover from light stress. Non-photochemical quenching (NPQ) was also affected by chloroplast contraction, with distal regions of the cell exhibiting significantly higher NPQ activation. These findings suggest that karyostrophy might serve as a complementary photoprotective mechanism, acting alongside whole-cell motility and NPQ. This study provides the first quantitative characterization of the light response of karyostrophy, highlighting its possible role in optimizing light utilization and protecting against photodamage.

In vivo chlorophyll fluorescence has long been known to be intimately related to photosynthesis, being the basis of widespread and sophisticated instrumentation. Although easily observed in plant extracts or using epifluorescence or confocal microscopes, chlorophyll fluorescence is seldom observed in macroscopic samples, such as plant leaves of macroalgae thalli. This work presents a 'chlorophyll fluoroscope', a device that allows the direct observation of the fluorescence emitted in vivo by large samples. The chlorophyll fluoroscope is easy to construct and operate, comprising inexpensive 3D-printed parts and off-the-shelve components. It is primarily intended for use in teaching and science demonstration events while having the potential to interest those who are aware of chlorophyll fluorescence yet often have never observed the phenomenon.

Accurate forecasts of the biological impacts of climate change require a better understanding of how small‐scale temperature variability affects individual physiology and population dynamics. However, doing so for intertidal species with large distribution ranges while accounting for the effects of local adaptation presents numerous technical challenges. Historically, studies assessing the thermal thresholds of intertidal species have primarily focused on high‐tide conditions. However, neglecting the stress experienced during low tides may lead to misinterpretations of critical thermal limits, overestimation of ecological niches and underestimation of delayed mortality effects. Here, we assessed the macroecological consequences of thermal stress on the cold‐adapted brown seaweed Ascophyllum nodosum across its European distribution. We collected specimens from 10 populations spanning latitudes 41° N–60° N and subjected them to simulated intertidal heat stress using a novel, custom‐built experimental set‐up that replicated realistic conditions, including tidal cycles, light conditions and temperature trajectories based on in situ data. Results indicate that thermal stress is more closely associated with the magnitude of temperature change between high and low tides rather than the absolute maximum temperatures reached. Notwithstanding, algae exposed to warmer water temperatures (20.5°C) consistently outperformed those in colder water (15°C), suggesting that cold upwelled waters at the species' southern limit may not be essential for survival. By integrating empirical physiological observations with state‐of‐the‐art climate projections, we found that some populations, though more resilient to thermal stress, could still be overwhelmed by the pace of warming, leading to uneven impacts across the European distribution of the species. Synthesis. Our findings underscore the importance of replicating realistic tidal cycles and temperature trajectories to accurately assess thermal stress in intertidal species, as temperature fluctuations between high and low tides drive the stress response. Our projections not only align with observed local extinctions but also indicate future trends, emphasising that species' responses to climate change will depend on their population‐specific sensitivity and local climate conditions. Even heat‐tolerant populations may struggle to keep pace with the rapid rate of warming, highlighting the vulnerability of intertidal ecosystems.

This study investigates whether the actin inhibitor Latrunculin B (Lat B) can be used to study the interplay between cellular motility and photosynthetic activity of pennate diatoms, by inhibiting their motility while not affecting their photosynthetic performance. The effects of increasing concentrations of Lat B (2.5, 5, and 10 mu M) on cellular motility (% motile cells) was measured on several species of pennate diatoms and on natural microphytobenthic assemblages. The species Entomoneis paludosa, Nitzschia longissima, Craspedostauros britannicus, and Pleurosigma strigosum were used for testing the existence of species-specific effects. The results showed that all tested concentrations of Lat B inhibited diatom motility in all studied species, with no decrease in efficacy over at least 5 hours. The effect of Lat B on photosynthetic activity (PSII electron transport rate and non-photochemical quenching) was tested at 2.5 mu M. Parameters extracted from light-response curves of relative electron transport rates of PSII (rETR vs E) and from light-induced photoprotection through thermal dissipation of energy (NPQ vs E) did not show common differences between treated and untreated cells. However, some species-specific effects were observed, underscoring the need for careful consideration when using chemicals, based on the specific model under study. Furthermore, treatment with Lat B did not affect the impact of high light exposure on PSII quantum yield. Nevertheless, Lat B appeared to partially reduce the ability of the cells to recover from high light stress, suggesting a potential involvement of actin filaments in photoinhibitory processes.

It has long been hypothesized that benthic motile pennate diatoms use phototaxis to optimize photosynthesis and minimize photoinhibitory damage by adjusting their position within vertical light gradients in coastal benthic sediments. However, experimental evidence to test this hypothesis remains inconclusive, mainly due to methodological difficulties in studying cell behavior and photosynthesis over realistic spatial microscale gradients of irradiance and cell position. In this study, a novel experimental approach was developed and used to test the hypothesis of photosynthesis optimization through motility, based on the combination of single-cell in vivo chlorophyll fluorometry and microfluidic chips. The approach allows the concurrent study of behavior and photosynthetic activity of individual cells of the epipelic diatom species Craspedostauros britannicus exposed to a light microgradient of realistic dimensions, simulating the irradiance and distance scales of light microgradients in benthic sediments. Following exposure to light, (i) cells explored their light environment before initiating light-directed motility; (ii) cells used motility to lower their light dose, when exposed to the highest light intensities; and (iii) motility was combined with reversible non-photochemical quenching, to allow cells to avoid photoinhibition. The results of this proof-of-concept study not only strongly support the photoprotective nature of photobehavior in the studied species but also revealed considerable variability in how individual cells reacted to a light microgradient. The experimental setup can be readily applied to study motility and photosynthetic light responses of other diatom species or natural assemblages, as well as other photoautotrophic motile microorganisms, broadening the toolset for experimental microbial ecology research.

The saltmarsh plant Halimione portulacoides was shortly exposed to realistic levels of inorganic mercury (iHg) with the aim of investigating the adaptative processes of the roots and leaves regarding redox homeostasis, physiology, and Hg accumulation. Plants were collected at a contaminated (CONT) and a reference (REF) site to address the interference of contamination backgrounds. The influence of major abiotic variables (i.e., temperature and light) was also examined. Total Hg levels, antioxidant enzymes, lipid peroxidation (LPO), and photosynthetic activity were analyzed after 2 and 4 h of exposure. A poor accumulation of Hg in the roots was noticed, and no translocation to the stems and leaves was found, but plants from the CONT site seemed more prone to iHg uptake (in winter). Despite this, antioxidant modulation in the roots and leaves was found, disclosing, in winter, higher thresholds for the induction of enzymatic antioxidants in CONT leaves compared to REF plants, denoting that the former are better prepared to cope with iHg redox pressure. Consistently, CONT leaves exposed to iHg had remarkably lower LPO levels. Exposure did not impair photosynthetic activity, pinpointing H. portulacoides’ ability to cope with iHg toxicity under very-short-term exposure. Biochemical changes were noticed before enhancements in accumulation, reinforcing the relevance of these responses in precociously signaling iHg toxicity.

This work presents a low-cost, open-source turbidimeter, the ‘Erlenmeter’, designed to monitor the growth of microorganisms in batch cultures. It is easy to build, based exclusively on inexpensive off-the-shelf electronic components and 3D-printed parts. The Erlenmeter allows measuring the optical density of cultures on standard Erlenmeyer flasks without the need to open the flasks to collect aliquots, ensuring speed, minimal use of consumables, and elimination of the risk of contamination. These features make it particularly well-suited not just for routine research assays but also for experimental teaching. Here we illustrate the use of the Erlenmeter turbidimeter to record the growth of the microalga Phaeodactylum tricornutum, of the bacterium Escherichia coli, and of the yeast Saccharomyces cerevisiae, model organisms that are widely used in research and teaching. The Erlenmeter allows a detailed characterization of the growth curves of all organisms, confirming its usefulness for studying microbial populations dynamics both for research purposes and in classroom settings.

BackgroundMicroscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) are the two major antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).ObjectivesTo characterize a homogenous AAV cohort and to assess the impact of clinicopathological profiles and ANCA serotypes on clinical presentation and prognosis. Clinical differences in GPA patients according to ANCA serotype and the diagnostic yield for vasculitis of biopsies in different territories were also investigated.ResultsThis retrospective study (2000-2021) included 152 patients with AAV (77 MPA/75 GPA). MPA patients (96.1% myeloperoxidase [MPO]-ANCA and 2.6% proteinase 3 [PR3]-ANCA) presented more often with weight loss, myalgia, renal involvement, interstitial lung disease (ILD), cutaneous purpura, and peripheral nerve involvement. Patients with GPA (44% PR3-ANCA, 33.3% MPO, and 22.7% negative/atypical ANCA) presented more commonly with ear, nose, and throat and eye/orbital manifestations, more relapses, and higher survival than patients with MPA. GPA was the only independent risk factor for relapse. Poor survival predictors were older age at diagnosis and peripheral nerve involvement. ANCA serotypes differentiated clinical features in a lesser degree than clinical phenotypes. A mean of 1.5 biopsies were performed in 93.4% of patients in different territories. Overall, vasculitis was identified in 80.3% (97.3% in MPA and 61.8% in GPA) of patients.ConclusionsThe identification of GPA presentations associated with MPO-ANCA and awareness of risk factors for relapse and mortality are important to guide proper therapeutic strategies in AAV patients. Biopsies of different affected territories should be pursued in difficult-to-diagnose patients based on their significant diagnostic yield. image

Giant cell arteritis (GCA) may manifest with aggressive intracranial stenosis resistant to medical therapy, and patients may develop refractory neurologic deficits and cerebral infarcts, making GCA a life-threatening condition. We report the case of a 68-year-old woman recently diagnosed with GCA, medicated with prednisolone 60 mg daily. Two weeks later, the patient was admitted to our Stroke Unit after a sudden episode of global aphasia. Magnetic resonance angiography showed two recent ischaemic lesions, besides an erythrocyte sedimentation rate of 17 mm/hour. A cerebral angiography revealed bilateral stenosis and dilation in the petrous, cavernous and supraclinoid segments of internal carotid arteries (ICA). The patient was started on intravenous methylprednisolone pulses (250 mg daily for five days). Computed tomography (CT) angiography and Doppler ultrasound showed severe vascular disease affecting multiple territories, without significant intracranial involvement. The hypothesis of GCA with extracranial vasculitic involvement was considered as the aetiology of ischaemic cerebral infarctions in multiple territories and, given the severity of the disease, it was decided to add tocilizumab. Despite this, the patient evolved with significant worsening neurological deficits and a CT scan confirmed the presence of new vascular events. Endovascular treatment (EVT) with balloon angioplasty was conducted on both ICAs, with improved calibre and downstream filling. After that, the patient presented sustained clinical improvement, without recurrence of any ischaemic events at the one-year follow-up. This clinical case stands out for the importance of EVT as an effective therapy in patients with medically refractory GCA with symptomatic intracranial stenosis, improving their prognosis.

Microphytobenthos (MPB) inhabiting intertidal flats are exposed to large and sudden changes in temperature, often simultaneously with exposure to direct sunlight. These conditions are expected to negatively impact photosynthesis by exacerbating the photoinhibition under high light. This study addressed the photoinhibitory effects of short-term exposure to cold (5°C) and moderate heat (35°C) on MPB dominated by motile epipelic (EPL) and immotile epipsammic (EPM) diatom species, by evaluating the seasonal variation of photoinactivation and repair of photosystem II (PSII). The susceptibility to PSII photoinactivation and the counteracting repair capacity were measured by the constant rates k PI and k REC , respectively. The photoacclimation state was characterized by hysteresis light-response curves (HLC) of the relative electron transport rate, rETR, and of the nonphotochemical quenching index Y(NPQ). Under non-stress conditions (20°C), k REC was on average almost 10x higher than the corresponding k PI (20.4 vs 2.70 × 10 −4 s −1 , respectively), indicating the operation of efficient repair mechanisms. Overall, the exposure to low and high temperatures affected both PSII photoinactivation and repair but causing smaller impacts in the former than in the latter. Also, cold stress caused larger effects on repair (decrease of k REC ) than on photoinactivation (increase of k PI ), but heat stress affected similarly the two processes. These effects varied seasonally, suggesting a role of thermal acclimation, as heat stress had stronger effects in cold-acclimated samples and cold stress resulted in stronger effects in heat-acclimated samples. The changes in k PI and k REC occurred despite the high light-acclimated phenotype found all year round, indicating that these processes vary independently from the photoacclimation state. The results also showed that photoprotection processes, as measured by energy-dependent non-photochemical index q E , appear to have an important role, both by preventing PSII photoinactivation and by alleviating the impacts on PSII repair under acute thermal stress.

Not only leaves but also other plant organs and structures typically considered as carbon sinks, including stems, roots, flowers, fruits and seeds, may exhibit photosynthetic activity. There is still a lack of a coherent and systematized body of knowledge and consensus on the role(s) of photosynthesis in these "sink" organs. With regard to fruits, their actual photosynthetic activity is influenced by a range of properties, including fruit anatomy, histology, physiology, development and the surrounding microclimate. At early stages of development fruits generally contain high levels of chlorophylls, a high density of functional stomata and thin cuticles. While some plant species retain functional chloroplasts in their fruits upon subsequent development or ripening, most species undergo a disintegration of the fruit chloroplast grana and reduction in stomata functionality, thus limiting gas exchange. In addition, the increase in fruit volume hinders light penetration and access to CO2, also reducing photosynthetic activity. This review aimed to compile information on aspects related to fruit photosynthesis, from fruit characteristics to ecological drivers, and to address the following challenging biological questions: why does a fruit show photosynthetic activity and what could be its functions? Overall, there is a body of evidence to support the hypothesis that photosynthesis in fruits is key to locally providing: ATP and NADPH, which are both fundamental for several demanding biosynthetic pathways (e.g., synthesis of fatty acids); O-2, to prevent hypoxia in its inner tissues including seeds; and carbon skeletons, which can fuel the biosynthesis of primary and secondary metabolites important for the growth of fruits and for spreading, survival and germination of their seed (e.g., sugars, flavonoids, tannins, lipids). At the same time, both primary and secondary metabolites present in fruits and seeds are key to human life, for instance as sources for nutrition, bioactives, oils and other economically important compounds or components. Understanding the functions of photosynthesis in fruits is pivotal to crop management, providing a rationale for manipulating microenvironmental conditions and the expression of key photosynthetic genes, which may help growers or breeders to optimize development, composition, yield or other economically important fruit quality aspects.

BACKGROUND: When the human population increases, so does the need to explore a wider range of feedstocks and biomasses, such as cyanobacteria. However, a deeper understanding of the growth patterns and pigment production is required to support the selection of the most beneficial species and conditions for industrial production. The growth and pigment production (i.e., chlorophyll a and C-phycocyanin) of three cyanobacterium species were evaluated following a three-fold aim. The first goal was to compare among a species commonly selected for exploitation (Arthrospira platensis) and two alternative species (Anabaena cylindrica and Nostoc muscorum). The second goal was analyzing pigment production in the long-term. The last goal involved comparing different methods (spectrophotometry and fluorimetry) to understand whether there is an appropriate proxy of biomass increase and pigment production that can be used for monitoring purposes. RESULTS: All species showed high longevity and proved capable of growing for more than 100 days without any additional supplementation. However, the maximum quantum yield of PS II (F-v /F-m) revealed that their photosynthetic efficiency varied over time with a clear decrease after 2 months. Pigment analysis showed a heterogeneous pattern during the growth periods of all three species that could only be captured by the parameter F-v /F-m, but the pattern was only present for A. cylindrica and N. muscorum in some stages of the culture period. CONCLUSION: N. muscorum was found to be the best chlorophyll a and C-phycocyanin producer, with the production peaking for all species at defined time periods within the growth profile. (C) 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Diatoms are an extraordinarily diverse, evolutionarily successful, and ecologically important group of single-cell algae. Diatoms of the group of the pennates are particularly important in estuarine sedimentary habitats, where they form highly productive microphytobenthos communities that cover extensive areas of intertidal flats. The pennates are capable of directed motility, an evolutionary and unique trait amongst diatoms, which has long been hypothesized to confer a critical adaptive advantage, by enabling these cells to vertically migrate within the photic zone of the sediment and behaviorally regulate light exposure. This study investigated the role of diatom motility on the active regulation of light exposure by developing a model to quantitatively characterize and compare the experienced light environment of individual cells of two life forms of pennate diatoms that inhabit intertidal estuarine sediments: epipelic species, motile cells dominant in fine sediments, and epipsammic species, non-motile or slowly motile cells, that colonize coarser sediments. The conceptual framework of the model was based on the identification and parameterization of the main controlling factors of the light regime perceived by cells inhabiting the two types of sedimentary environments: (i) solar irradiance incident at the sediment surface, determined by the superimposition of the tidal cycle on the day-night cycle; (ii) light attenuation within the sediment; (iii) sediment mixing by tidal currents or bioturbation, repositioning the cells in the sediment column; (iv) cell velocity, as a function of light intensity and of the photoacclimation state of the cells that determines their photosynthetic light preferences. The model was run for realistic scenarios based on published ecological, photophysiological and cellular motility data (light attenuation, mixing depth, photosynthesis light-response curves, cell velocity), simulating (i) the variation in the vertical position of a diatom cell due to vertical migration and (ii) the irradiance level to which it is exposed at each moment. The results confirm the hypothesis that epipelic and epipsammic diatoms experience a significantly different light environment. Vertical migration enables motile species to experience a much less variable light regime, with increased mean daily light doses received. In contrast, non-motile species experience a much more unstable light environment, including the frequent exposure to supersaturating light levels and to periods of prolonged darkness. These results have important ecological significance, as they support the adaptive value of light-driven motility as a form of opti-mizing photosynthesis and growth, and they identify vertical migration as a niche-construction activity, allowing motile diatoms to regulate the light environment they experience through habitat selection.

Background Status epilepticus (SE) is a medical condition that bestows substantial morbidity and mortality. Literature is scarce regarding SE in elderly patients, particularly in the context of internal medicine wards. Aim To characterize SE patients admitted to an internal medicine ward, identify potential outcome predictors and differences between young and elderly, as well as convulsive (CSE) and non-convulsive SE (NCSE) patients. Methods We enrolled 135 consecutive patients in an observational, retrospective cohort study. We established elderly patients as more than 64 years old and defined worse prognosis as a modified Rankin Scale (mRS)>4. Results The SE population was 73% elderly, and 75% presented with NCSE, mainly metabolic, idiopathic, or vascular SE. The intra-hospital mortality was 51%, and 62% had an mRS>4 at discharge. NCSE and electroencephalogram (EEG) with paroxysmal activity at discharge were predictive of a worse prognosis. Elderly patients had increased disability at admission, most had NCSE (81%), and the SE etiology differed with more idiopathic and vascular causes. In the elderly, mortality was increased, as was the number of patients with mRS>4 at discharge. NCSE patients had the more neurodegenerative disease (30%) and presented predominantly with vascular and anoxic causes. Morbidity and mortality were also increased in the NCSE group. There was no difference in the antiepileptic drugs used or in the percentage of patients achieving an EEG with no paroxysmal activity between the subpopulations. Conclusion SE in elderly patients should be addressed distinctly. Current approaches based on the strategies used for standard CSE have shown little or no efficacy overall.

Sacoglossa are known for stealing photosynthetically active chloroplasts from their macroalgal food and incorporating them into their cytosol. The nutritional support these alien organelles (kleptoplasts) provide to the slugs is still debatable. Comparing slugs starved in continuous darkness (non-photosynthetic condition) and light (photosynthetic condition) is often used to understand the contribution of the kleptoplasts to the slugs' metabolism. Here, we examined the slugs' side of starvation in darkness to better understand the effects of darkness on the slugs. We compared the gene expression profile and digestive activity of Elysia viridis , starved for one week under ambient light and continuous darkness. Starvation in darkness led to the up-regulation of genes related to glucose deficiency, while genes involved in the development, cellular organization, and reproduction were down-regulated. This specific gene expression may counteract reduced nutrient availability under non-photosynthetic conditions. Under photosynthetic conditions, kleptoplasts may have a higher nutritional value and may be able to support some metabolic processes. It appears that the slugs can only access kleptoplast photosynthates through autophagy during starvation. Nevertheless, autophagy and length reduction in darkness are highly elevated compared to light conditions, suggesting that more slug tissue is needed to satisfy the nutritional demands under non-photosynthetic conditions. Since we did not detect a gene expression related to the export of photosynthates to the slugs, our results support the hypothesis that slugs use kleptoplasts as larders accessible via autophagy. As long as the kleptoplasts are functional, they provide an energetic support, helping the slugs to reduce starvation-induced stress.

The production of reactive oxygen species (ROS) is an unavoidable consequence of oxygenic photosynthesis and represents a major cause of oxidative stress in phototrophs, having detrimental effects on the photosynthetic apparatus, limiting cell growth, and productivity. Several methods have been developed for the quantification of cellular ROS, however, most are invasive, requiring the destruction of the sample. Here, we present a new methodology that allows the concurrent quantification of ROS and photosynthetic activity, using the fluorochrome dichlorofluorescein (DCF) and in vivo chlorophyll a fluorescence, respectively. Both types of fluorescence were measured using an imaging Pulse Amplitude Modulation (PAM) fluorometer, modified by adding a UVA-excitation light source (385 nm) and a green bandpass emission filter (530 nm) to enable the sequential capture of red chlorophyll fluorescence and green DCF fluorescence in the same sample. The method was established on Phaeodactylum tricornutum Bohlin, an important marine model diatom species, by determining protocol conditions that permitted the detection of ROS without impacting photosynthetic activity. The utility of the method was validated by quantifying the effects of two herbicides (DCMU and methyl viologen) on the photosynthetic activity and ROS production in P. tricornutum and of light acclimation state in Navicula cf. recens Lange-Bertalot, a common benthic diatom. The developed method is rapid and non-destructive, allowing for the high-throughput screening of multiple samples over time.