This review describes compounds produced microalgae, such as biodiesel, lipids, fatty acids (FA), triacylglycerides (TAG), and pigments (phycobilins, chlorophylls, and carotenoids). We discuss the ...factors inducing the accumulation of these metabolites and their economic importance. We focused on cell wall breaking methods of microalgae used to produce biodiesel. A special approach was made to extremophile microalgae used in biodiesel production. The type of methodology used in the cultivation and the use of extremophiles microalgae can permit feasible biodiesel production.
In the search for microalgae species with potential for biodiesel production, Choricystis minor var. minor has been seen as a promising source of biomass due to its high lipid content and the ...satisfactory characteristics of its fatty acid methyl esters (FAMEs). For this reason, the objective of this study was to investigate the synergistic effect of growth conditions and organic carbon sources on cultivation of this microalga. To do so, experimental cultivations were conducted in photoautotrophic, heterotrophic and mixotrophic metabolisms using glucose, fructose, glycerol or sucrose – in growth conditions that use organic carbon. Thus, growth parameters of the cultures were evaluated and at the end of the cultivations, FAMEs yield and profile were determined by gas chromatography, the efficiency of carbon conversion into biomass was evaluated and a microbial analysis was conducted. Regarding growth conditions, the findings have confirmed that, regardless of the organic carbon source used, the heterotrophic and mixotrophic metabolisms can present advantages over the photoautotrophic one. In addition, biomass production was higher with the use of glucose than with other organic carbon sources, regardless of growth condition (heterotrophic or mixotrophic). Moreover, cultivations with the addition of CO2 have converted carbon into biomass less efficiently. On the other hand, photoautotrophic cultures presented the lowest bacterial load. In comparison to photoautotrophic and mixotrophic, heterotrophic cultures have led to lower FAMEs content and higher yields of unsaturated fatty acids. The most satisfactory FAMEs profile for biodiesel production was obtained with mixotrophic growth using fructose.
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•The synergetic effect of growth conditions and organic carbon sources was investigated.•The addition of organic carbon has promoted an increase in the Choricystis minor var. minor biovolume.•Mixotrophic cultures have improved biomass production and FAMEs yield.•Mixotrophic cultures using fructose have increased saturated fatty acids content.•The use of glycerol and sucrose in the presence of light has probably induced photoheterotrophy.
The present study reports the development of a bioassay using Artemia spp. to analyse the preliminary ecotoxicity of atmospheric aerosols (PM), which can affect the environment and human health. ...Herein, PM samples were collected in the city of Goiânia (Brazil) in 2016, extracted with ultrapure water and subsequently filtered through membranes with different pore sizes (100, 0.8, and 0.22 μm), and the extracts employed in the bioassays. The mortality rates (endpoint analysed) declined to membranes with smaller pore sizes (15 ± 4%, 47 ± 10% and 43 ± 9% for pore sizes of 100 μm, 0.8 μm and 0.22 μm, respectively). In general, the toxicity of the extract depended on its concentration, except for the sample with a higher negative particle surface charge, which presents a lower affinity for the negatively charged surfaces of cellular membranes. Moreover, although the PM concentration was higher for the sample collected during the dry season (September), the mortality rate was not significantly different to that determined for a sample with similar physical and chemical characteristics collected in the rainy season (December). This result demonstrates the importance of monitoring PM toxicities and their chemical and physical characteristics, in addition to their concentrations. Therefore, the new protocol to provide a preliminary analysis of the toxicity of the extracts of aerosol emerges as a useful, accessible, and fast tool for monitoring possible environmental hazards, and can simplify fieldwork.
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•A new protocol to measure the preliminary ecotoxicity of atmospheric aerosol samples.•The ecotoxicological impact of atmospheric aerosol upon Artemia spp.•Aerosol samples collected in the dry and wet seasons exhibit ecotoxicity.•The toxicity showed dependence on particle size and concentration.
An innovative volatolomic approach employs the detection of biomarkers present in cerumen (earwax) to identify cattle intoxication by Stryphnodendron rotundifolium Mart., Fabaceae (popularly known as ...barbatimão). S. rotundifolium is a poisonous plant with the toxic compound undefined and widely distributed throughout the Brazilian territory. Cerumen samples from cattle of two local Brazilian breeds (‘Curraleiro Pé‐Duro’ and ‘Pantaneiro’) were collected during an experimental intoxication protocol and analyzed using headspace (HS)/GC–MS followed by multivariate analysis (genetic algorithm for a partial least squares, cluster analysis, and classification and regression trees). A total of 106 volatile organic metabolites were identified in the cerumen samples of bovines. The intoxication by S. rotundifolium influenced the cerumen volatolomic profile of the bovines throughout the intoxication protocol. In this way, it was possible to detect biomarkers for cattle intoxication. Among the biomarkers, 2‐octyldecanol and 9‐tetradecen‐1‐ol were able to discriminate all samples between intoxicated and nonintoxicated bovines. The cattle intoxication diagnosis by S. rotundifolium was accomplished by applying the cerumen analysis using HS/GC–MS, in an easy, accurate, and noninvasive way. Thus, the proposed bioanalytical chromatography protocol is a useful tool in veterinary applications to determine this kind of intoxication.
The development of chemoresistance to paclitaxel and carboplatin represents a major therapeutic challenge in ovarian cancer, a disease frequently characterized by malignant ascites and extrapelvic ...metastasis. Microtentacles (McTNs) are tubulin-based projections observed in detached breast cancer cells. In this study, we investigated whether ovarian cancers exhibit McTNs and characterized McTN biology.
We used an established lipid-tethering mechanism to suspend and image individual cancer cells. We queried a panel of immortalized serous (OSC) and clear cell (OCCC) cell lines as well as freshly procured ascites and human ovarian surface epithelium (HOSE). We assessed by Western blot β-tubulin isotype, α-tubulin post-translational modifications and actin regulatory proteins in attached/detached states. We studied clustering in suspended conditions. Effects of treatment with microtubule depolymerizing and stabilizing drugs were described.
Among cell lines, up to 30% of cells expressed McTNs. Four McTN morphologies (absent, symmetric-short, symmetric-long, tufted) were observed in immortalized cultures as well as ascites. McTN number/length varied with histology according to metastatic potential. Most OCCC overexpressed class III ß-tubulin. OCCC/OSC cell lines exhibited a trend towards more microtubule-stabilizing post-translational modifications of α-tubulin relative to HOSE. Microtubule depolymerizing drugs decreased the number/length of McTNs, confirming that McTNs are composed of tubulin. Cells that failed to form McTNs demonstrated differential expression of α-tubulin- and actin-regulating proteins relative to cells that form McTNs. Cluster formation is more susceptible to microtubule targeting agents in cells that form McTNs, suggesting a role for McTNs in aggregation.
McTNs likely participate in key aspects of ovarian cancer metastasis. McTNs represent a new therapeutic target for this disease that could refine therapies, including intraperitoneal drug delivery.
Volatile organic compounds (VOCs) from microalgae have many applications in several industries, and their synthesis can be affected by several factors, such as light and growth phase. Thus, this ...study aimed to determine the influence of different irradiances and growth phases on the VOC profile of
Arthrospira platensis
and
Chlorella
sp. Biomasses of cultures subjected to 200 and 1000 µmol photons m
−2
s
−1
and harvested in the exponential and stationary growth phases were analyzed by gas chromatography and mass spectrometry. Twelve VOCs were found in the biomasses of
A. platensis
and 34 in the biomasses of
Chlorella
sp., with only five compounds in common for both species. In the biomasses of
A. platensis
, many hydrocarbons were found, being this class the one with the greatest representative in this species VOC profile. Octadecane, which may have several applications in the food industry, was the predominant compound, showing high values under 1000 µmol photons m
−2
s
−1
in the stationary growth phase. On the other hand, in
Chlorella
sp. biomasses, a variety of nitrogenous compounds was found, and octadecyl vinyl ether had the highest values under 200 µmol photons m
−2
s
−1
in the stationary phase. A couple of terpenoids were found in both microalgae, except safranal, which was only detected in
Chlorella
sp. In conclusion, the results confirm that both the irradiance and growth phase influenced the VOC profile of
A. platensis
and
Chlorella
sp. as changes in the percentage and types of VOCs present in each species were observed in the cultivation conditions evaluated.
Tractography based on non-invasive diffusion imaging is central to the study of human brain connectivity. To date, the approach has not been systematically validated in ground truth studies. Based on ...a simulated human brain data set with ground truth tracts, we organized an open international tractography challenge, which resulted in 96 distinct submissions from 20 research groups. Here, we report the encouraging finding that most state-of-the-art algorithms produce tractograms containing 90% of the ground truth bundles (to at least some extent). However, the same tractograms contain many more invalid than valid bundles, and half of these invalid bundles occur systematically across research groups. Taken together, our results demonstrate and confirm fundamental ambiguities inherent in tract reconstruction based on orientation information alone, which need to be considered when interpreting tractography and connectivity results. Our approach provides a novel framework for estimating reliability of tractography and encourages innovation to address its current limitations.
Invasive aspergillosis (IA) is a fungal infection that particularly affects immunocompromised hosts. Recently, several studies have indicated a high incidence of IA in intensive care unit (ICU) ...patients. However, few data are available on the epidemiology and outcome of patients with IA in this setting.
An observational study including all patients with a positive Aspergillus culture during ICU stay was performed in 30 ICUs in 8 countries. Cases were classified as proven IA, putative IA or Aspergillus colonization according to recently validated criteria. Demographic, microbiologic and diagnostic data were collected. Outcome was recorded 12 weeks after Aspergillus isolation.
A total of 563 patients were included, of whom 266 were colonized (47%), 203 had putative IA (36%) and 94 had proven IA (17%). The lung was the most frequent site of infection (94%), and Aspergillus fumigatus the most commonly isolated species (92%). Patients with IA had higher incidences of cancer and organ transplantation than those with colonization. Compared with other patients, they were more frequently diagnosed with sepsis on ICU admission and more frequently received vasopressors and renal replacement therapy (RRT) during the ICU stay. Mortality was 38% among colonized patients, 67% in those with putative IA and 79% in those with proven IA (P < 0.001). Independent risk factors for death among patients with IA included older age, history of bone marrow transplantation, and mechanical ventilation, RRT and higher Sequential Organ Failure Assessment score at diagnosis.
IA among critically ill patients is associated with high mortality. Patients diagnosed with proven or putative IA had greater severity of illness and more frequently needed organ support than those with Aspergillus spp colonization.
Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene ...catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio‐oceanographic and bio‐omics data sets from Tara Oceans in the context of the iron products from two state‐of‐the‐art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large‐scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment.
Plain Language Summary
Marine phytoplankton require iron for their growth and proliferation. According to John Martin's iron hypothesis, fertilizing the ocean with iron could dramatically increase photosynthetic activity, thus representing a biological means to counteract global warming. However, while there is a constantly growing knowledge of how iron is distributed in the ocean and about its role in cellular processes in marine photosynthetic groups such as diatoms and cyanobacteria, less is known about how iron availability shapes plankton communities and how they respond to it. In the present work, we exploited recently published Tara Oceans data sets to address these questions. We first defined specific subcommunities of co‐occurring organisms that co‐vary with iron availability in the oceans. We then identified specific patterns of adaptation and acclimation to iron in different groups of phytoplankton. Finally, we validated our global results at local scale, specifically in the Marquesas archipelago, where recurrent phytoplankton blooms are believed to be a result of iron fertilization. By integrating global data with a localized response, we provide a framework for understanding the resilience of plankton ecosystems in a changing environment.
Key Points
Coherent assemblages of taxa covarying with iron at global level are identified in plankton communities
Functional responses to iron availability involve both changes in copy numbers of iron‐responsive genes and their transcriptional regulation
Plankton responses to local variations in iron concentrations recapitulate global patterns
The ACTA2 gene encodes for smooth muscle specific α-actin, a critical component of the contractile apparatus of the vascular smooth muscle cell. Pathogenic variants in the ACTA2 gene are the most ...frequently encountered genetic cause of non-syndromic hereditary thoracic aortic disease (HTAD). Although thoracic aortic aneurysm and/or dissection is the main clinical manifestation, a variety of occlusive vascular disease and extravascular manifestations occur in ACTA2-related vasculopathy. Current data suggest possible mutation-specific manifestations of vascular and extra-aortic traits.Despite its relatively high prevalence, comprehensive recommendations on the care of patients and families with pathogenic variants in ACTA2 have not yet been established. We aimed to develop a consensus document to provide medical guidance for health care professionals involved in the diagnosis and treatment of patients and relatives with pathogenic variants in ACTA2.The HTAD Working Group of the European Reference Network for Rare Vascular Diseases (VASCERN) convened to review current literature and discuss expert opinions on clinical management of ACTA2 related vasculopathy. This consensus statement summarizes our recommendations on diagnosis, monitoring, treatment, pregnancy, genetic counselling and testing in patients with ACTA2-related vasculopathy. However, there is a clear need for additional prospective multicenter studies to further define proper guidelines.
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