The Cyanobacterium
Oculatella subterranea
Zammit, Billi, Albertano inhabits hypogea and stone caves and is a pioneer of different stone substrata. In this study, a strain isolated from the House of ...Marco Castricio (Archaeological Park of Pompeii, Italy) was identified by a polyphasic approach and used for an in vitro colonization test to verify the influence of the substrate on the biofilm architecture. Fine structure of
O. subterranea
microbial mats was revealed as well as filaments orientation toward light source. This aim has been achieved through confocal laser scanner microscope microscopy and computer image analysis. Moreover, bioreceptivity of five different substrates, commonly retrieved in archaeological sites of Campania, was assessed for
O. subterranea
. Our results show that the three-dimensional structure of
O. subterranea
microbial mats is poorly affected by physical and geochemical features of substrates: in fact, the porous architecture of its biofilm was preserved, independently of the materials. On the other hand, the area/perimeter ratio relative to the
O. subterranea
growth on tuff, brick, and porphyry showed significant differences, indicating dissimilar levels of bioreceptivity of the three substrates.
The role of extracellular fatty acids in the interference between two algae, Chlorella vulgaris Beijerink and Pseudokirchneriella subcapitata (Korshikov) Hindak, was assessed by the co-cultivation of ...the two selected strains, as well as by the chemical analysis of exudates from the culture media of single strain cultures. The effect of culture age and phosphate limitation was evaluated. The experiments showed that the composition and amount of fatty acids, released by C. vulgaris and by P. subcapitata, both in a batch and in a continuous monoculture, depend on the culture age and on the phosphate concentration in the culture medium. We also found that the amount of chlorellin generated in the two algae co-culture increased and was almost exclusively constituted by a mixture of C18 fatty acids. By using the evaluated concentrations of these fatty acids, an artificial chlorellin was prepared. The toxicity of this mixture to P. subcapitata appears to be similar to that of the natural chlorellin. For both algae, a stimulation of growth was observed at low concentrations of the natural chlorellin, whereas higher concentrations produced inhibitory effects on both species. However, P. subcapitata was much more sensitive than C. vulgaris. By using some of these new experimental results, two new mathematical models have been used to describe the toxicity of chlorellin to C. vulgaris and to the interference between C. vulgaris and P. subcapitata, respectively.
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•Direct transesterification of Stichococcus genus without any extraction.•The maximum bio-oil yield was close to 17% under alkaline conditions.•Influence of the catalyst, ...methanol/biomass weight ratio, time and temperature.•The pre-contact time did not affect bio-oil yield.•The increase of biomass water content significantly reduced the bio-oil yield.
The cost of bio-oil refining from microalgal biomass can be significantly reduced by combining extraction and transesterification. The characterisation and optimisation of the combined steps have been carried out on strains of Stichococcus bacillaris, focusing on catalyst type and concentration, reaction time and temperature, methanol/biomass ratio, pre-mixing time and water content in the biomass. The bio-oil yield has been referenced as production of fatty acid methyl esters (FAMEs). The maximum yield (∼17%) was achieved using dried biomass with alkaline catalyst at 60°C and methanol/biomass weight ratio of 79:1. Alkaline catalyst conditions gave faster reaction rates and higher bio-oil yields than acid catalyst. Yield was also strongly affected by water content in the biomass. A mechanistic interpretation has been proposed to elucidate the effect of the different operating conditions. However, the structural characteristics of the Chlorophyta cell wall can be very different, leading to different bio-oil yields when the same protocol is applied. Therefore, the optimised protocol of direct transesterification for Stichococcus bacillaris strains was tested on other Stichococcus strains and several other Chlorophyta species characterised by a different cell wall structure. It was clearly demonstrated that different results for bio-oil yield were obtained within the same microalgal species and much more within different microalgal genera.
Background and aim: Nontraumatic intracerebral hemorrhage (ICH) remains a devastating disease for high in-hospital and long-term mortality and residual neurological disability. The aim of our study ...was to analyze the prognostic factors in patients managed for ICH in the real-life clinical practice.
Materials and Methods: We retrospectively analyzed clinical and neuro-radiological data of consecutive patients admitted to our Hospital for ICH along 1 year. In-hospital mortality and 90-day modified Rankin scale (mRS) ≥4 were the study outcomes. Moreover, we compared patients admitted in Intensive Care Unit (ICU) with patients admitted in Stroke Unit (SU).
Results: Ninety-eight patients with mean age ± SD 78 ± 12 years were enrolled. In-hospital and 90-day mortality were 36.7% and 41.8%, respectively. Patients who died had a significantly higher percentage of ICH volume >30 mL, irregular shape, lobar location, intraventricular hemorrhage (IVH), midline shift, hydrocephalus, hematoma enlargement, Glasgow Coma Scale (GCS) ≤9 at hospital admission, early neurological worsening (ENW), higher Hemphill ICH score, and underwent oro-tracheal intubation more frequently compared with patients who survived. Patients admitted to ICU were younger and significantly more critical compared with those who were admitted to SU. In-hospital mortality in patients admitted to ICU was 52.6% compared with 25% in patients admitted to SU (p < 0.01). Median mRS score at hospital discharge was 4 (IQR 3-5) and at 90 days was 4 (IQR 3-4). ENW, hematoma enlargement, Hemphill ICH score ≥3 and midline shift >10 mm were found independent risk factors for in-hospital mortality, while age was found as independent risk factor for 90-day mRS ≥4).
Conclusion: In real life, prognosis of ICH is associated with clinical and radiological determinants. In our study ENW, hematoma enlargement, Hemphill ICH score ≥3 and midline shift >10 mm were associated with short-term mortality risk, while age with 90-day mRS ≥4.
ABSTRACT
Microalgae biofilms may play an important role in the mitigation and prevention of eutrophication caused by domestic, agricultural and industrial wastewater effluents. Despite their ...potential, the biofilm development and role in nutrient removal are not well understood. Its clarification requires comprehensive studies of the complex three-dimensional architecture of the biofilm. In this study, we established a multimodal imaging approach to provide key information regarding architecture development and nutrient distribution in the biofilm of two green algae organisms: Chlorella pyrenoidosa and Chlorella vulgaris. Helium ion microscopy (HIM), scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed for i) elucidation of spatial arrangement, ii) elemental mapping and iii) 3D chemical imaging of the biofilm. The fine structure of the algal biofilm was resolved by HIM, the evidence of the accumulation of phosphate in hot spots was provided by SEM-EDX and the localization of phosphate oxides granules throughout the whole sample was clarified by ToF-SIMS. The reported results shed light on the phosphorus distribution during Chlorella's biofilm formation and highlight the potential of such correlative approach to solve fundamental question in algal biotechnology research.
Multimodal imaging to investigate phosphorous distribution in the biofilm of two green algae species, Chlorella pyrenoidosa and Chlorella vulgaris.
► The cDNA laccase of fungal poxA1b gene was transferred into genome of
Nicotiana tabacum and 5 microalgae species ► The transgenic plants and microalgae correctly expressed the fungal gene. ► The ...removal ability to OMWs phenols in those green organism were significantly enhanced.
Olive oil mill wastewaters (OMWs) are characterised by low pH and a high content of mono- and polyaromatic compounds that exert microbial and phytotoxic activity. The laccase cDNA of the
poxA1b gene from
Pleurotus ostreatus, carrying a signal peptide sequence for enzyme secretion and driven by the CaMV 35S promoter, was cloned into a plant expression vector. Nuclear genetic transformation was carried out by co-cultivation of
Agrobacterium tumefaciens with tobacco cv Samsun NN leaves and cells of five different microalgae accessions belonging to the genera
Chlamydomonas,
Chlorella and
Ankistrodesmus. Transgenic plants and microalgae were able to express and secrete the recombinant laccase in the root exudates and the culture medium, respectively. In comparison to untransformed controls, the ability to reduce phenol content in OMW solution was enhanced up to 2.8-fold in transgenic tobacco lines and by up to about 40% in two microalgae accessions. The present work provides new evidence for metabolic improvement of green organisms through the transgenic approach to remediation.
The aquatic toxicity of sulfaquinoxaline (SQO) and sulfaguanidine (SGD) was evaluated on the following test organisms:
Daphnia magna (reproduction test),
Pseudokirchneriella subcapitata,
Scenedesmus ...dimorphus,
Synecococcus leopoliensis (algal growth inhibition test) and
Lemna gibba (duckweed growth inhibition test). Furthermore, the additivity of the two compounds was measured on
D. magna (acute immobilisation test) and
P. subcapitata (algal growth inhibition test) using the isobologram method. Results show that SQO and SGD are more toxic to green algae and daphnids, respectively, than other veterinary sulfonamides (SAs) and that their mixtures have a less then additive interaction. Taking into account the highest concentrations detected so far in surface waters for SQO (0.112
μg
L
−1) and for SGD (0.145
μg
L
−1) and the lowest NOECs obtained with the five test organisms, divided by an assessment factor of 10, the following PNECs and risk quotients (RQs) were calculated. SQO: PNEC 2
μg
L
−1; RQ 0.056. SGD: PNEC 39.5
μg
L
−1; RQ 0.004. Consequently, at the concentrations actually detected in the aquatic environment, the two SAs alone should not harm the freshwater organisms. However, it seems advisable, for veterinary mass treatments, the use of other SAs that have a lesser impact on the aquatic environment. Furthermore, considering the high probability of having complex mixtures of different SAs residues in water, each individual contamination should be evaluated by applying to the SAs mixtures the conservative criteria of additivity.
Purpose
A deep survey of biodeteriogen microorganisms reported on stone monuments in Europe has been performed based on the available literature dating back to over 30 years.
Methods
The obtained ...lists for eukaryotic algae, phototrophic and non-phototrophic bacteria, and fungi were sorted by Genera, and corresponding sequences in triplicate were downloaded by nucleotide database Genbank for a number of selected barcoding markers. On the basis of collected bibliometric diversity, multiple nucleotide alignments were produced and primers were designed for a qPCR assay. The aim of the present study was to obtain accurate oligos for the characterization of subaerial biofilms on the basis of the most comprehensive collection of reports and case studies regarding subaerial biofilms, with particular regard to phototrophic and non-phototrophic bacteria, eukaryotic algae, and molds.
Result
Primers were designed on conserved regions flanking a variable region, specific for each of the studied groups of microorganisms. Standard curve for absolute quantification relative to each group were determined for four markers. Then, variable regions in the alignments were used to design fluorescent internal probes for qPCR aimed for a multiplex reaction in which relative abundance can be determined.
Conclusion
The authors propose this kind of cost-effective approach in the study of biofilms for the estimation of algae, molds, and bacteria both for direct in situ analysis and in vitro simulation.
In the last decades, the use of pesticides has grown worldwide. However, there is great worry about the impact of pesticides on human health, due to their wide distribution and possible long-term ...effects. Complex mixtures with different formulations are often used, including a variety of genotoxic compounds. Thus, genotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. This study aimed to conduct a meta-analytical review of possible genetic damage resulting from occupational exposure in farmworkers and workers employed in pesticide production, both ever in comparison to non-exposed people, using comet assay (CA), micronucleus test (MN) and telomere length (TL) data available in the scientific literature. A total of 145 datasets were evaluated. The results showed that the occupationally exposed workers had more DNA damage in CA and MN than non-exposed workers. The TL result did not show difference between groups. When the data were categorized by gender (male, female or both), crop (general, tobacco, fruits, soybeans, cotton) and occupation (manufacturing or farmworkers), the study found that the exposed group always presented higher damage than the non-exposed individuals, in CA and MN. More studies with TL are needed to obtain a more precise response, and to segregate the effect of tobacco farming from pesticide exposure. When TL was segregated by gender, women and men presented difference between exposed and non-exposed groups. In general, the publication bias impact was modest. If all relevant studies were included, the key finding (i.e. the effect of pesticide exposure increases the genotoxicity and mutation rate) would probably remain unchanged. Lastly, it is important to highlight the importance of the use of personal protective equipment (PPE), and offer safer options to farmworkers (e.g. organic farming or less toxic alternatives).
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•Meta-analytical review of genetic damage after occupational exposure to pesticides•145 sets evaluated: comet assay (CA), micronucleus test (MN), telomere length (TL)•Occupationally exposed workers had more DNA damage in CA and MN than non-exposed.•About genders, crops, occupations: higher damage in exposed group through CA and MN•More studies with TL are needed to obtain a more concise response.
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