A method for studying the influence of Mn oxyhydroxides on the trace element content of aquatic bryophytes.

The main objective of this study was to develop and test a method of separating externally deposited Mn oxyhydroxides and co-precipitated elements from samples of aquatic moss (the moss Fontinalis antipyretica). The method, which uses 0.1 M hydroxylamine to dissolve the oxyhydroxides, was tested with samples collected in rivers with slightly acidic, well­oxygenated waters, where high rates of Mn precipitation occur. The method was effective (it extracted up to 84 % of the Mn) and selective (Fe oxyhydroxides were not extracted). The elements Ba, Cd, Zn and Ni were associated with the Mn oxyhydroxides, while Al, As, Cr, Cu, Fe, Hg and Pb were not. Deposition of Mn therefore increased the concentration of some elements in the moss samples. However, as Mn precipitation depends on Eh and pH, which are independent of the concentrations of the elements in water, the relationship between water and moss element concentrations is not clear (i.e. the data are noisy). This is a problem in biomonitoring studies, which assume a close relationship between element concentrations in moss and water. The value of the proposed extraction method is that it can be used to correct the effect of Mn deposition. We present an example of this correction applied to the Cd concentrations in the test data. We found that the noise introduced by the Mn, including age-related effects (observed by comparing concentrations in 0-2.5 and 2.2-5.0 cm sections from the shoot apex), can be reduced. Additionally, the correction revealed recent increases in Cd concentrations in one site that were not observed in the uncorrected data. Another finding of interest was the low content of total Mn and different extractability (of most elements) observed in moss samples collected in alkaline waters. Finally, we discuss how future studies designed for different environmental scenarios can benefit from application of the proposed method.

Removal of potentially toxic elements from water with the moss-tufa micro-filtration system.

Mosses are an integral component in the tufa sedimentary landscape. In this study, we investigated the use of the porous moss-tufa structure as a filtration system for removing potentially toxic elements (PTEs) from water samples. Three species of mosses that commonly grow on tufa were selected, and the PTEs filtered by the moss-tufa system were identified by inductively coupled plasma mass spectrometry. The bioconcentration factor (BCF) of mosses was calculated to compare the enrichment effects of different mosses on PTEs. Likewise, the level of PTEs flowing through the moss-tufa system was measured, and the water quality removal rate (C) was calculated accordingly. The results revealed that the moss-tufa system was mainly composed of Fissidens grandifrons Brid., Hydrogonium dixonianum P. C. Chen, and Cratoneuron filicinum (Hedw.) Spruce var. filicinum. Among these, Fissidens grandifrons Brid. reported the highest retention capacity for PTEs. Collectively, the moss-tufa filtration system displayed a strong retention capacity and removal rate of Mn, Pb, and Ni from the water sample. The removal of PTEs by the moss-tufa system was mainly based on the enrichment of mosses and the adsorption-retention ability of tufa. In conclusion, the moss-tufa micro-filtration system displayed the effective removal of PTEs from water samples and could be applied to control the levels of toxic elements in karst water bodies.

Significance of moss pretreatments in active biomonitoring surveys.

The present study examines the impact of pretreatment procedures on the metal concentrations in bags that are to be exposed. We examine Mn, Fe, Cu, Zn, Cd, and Pb amounts in Sphagnum fallax and Dicranum polysetum mosses using atomic absorption spectrometry. The concentration of Hg was also determined using a mercury analyzer. Two sample preparation ways were tested (with and without rinsing) and their influence was evaluated by determining the coefficient of variation (CV). Chlorophyll content was also determined in mosses collected from three habitats (deep woodland, forest road, and wood lot). The results indicate, that the concentration of elements deposited in mosses depends on the species and the habitat where they were collected (ANOVA, p < 0.001). Rinsing of mosses reduces the CV for Mn, Fe, Cu, and Zn and uniform the material prior to exposure (CV for the majority of metals <10%). Selected correlations were found for element concentrations with chlorophyll content. Photosynthetic activity of mosses decreased by about 80% during their one-month storage in the laboratory. Due to the varying concentration of metals in the collected samples, proper, and standardized preparation of mosses before exposure, they can be effectively used in active biomonitoring.

Compared to other biomonitoring work the novel approach is the simultaneous study of two moss species, the analysis of three different habitats and the tie-in of accumulated trace elements by mosses and their vitality by measuring chlorophyll content and photosynthetic activity.

Combined effect of fungicide, herbicide and plant elicitor used in apple orchards on non-target epiphytic moss Hypnum cupressiforme.

Apple production is a dynamic agricultural system in which pesticides are applied recurrently to control pests and diseases in the orchards. Understanding the impact of such agents on non-target organisms is crucial to minimise unintended consequences while maintaining their use in crop protection. The aim was to test how fungicide, herbicide, elicitor, and their combinations affect the physiology of the epiphytic moss Hypnum cupressiforme that naturally occurs in orchards. Our results showed that both dodine and diflufenican applied separately had a strong negative effect on moss physiology reflected in significantly decreased photosynthetic pigment contents, maximum quantum yield of PSII photochemistry, cell membrane integrity and dehydrogenase activity, and increased membrane lipid peroxidation, which indicates a high physiological stress. Furthermore, the combined use of herbicide and fungicide resulted in further deterioration of the physiological condition compared to the effects of both agents used separately. In many cases, the application of chitosan together with a diflufenican or dodine resulted in a reduction of the negative effects triggered by these agents. The compensatory effect was particularly pronounced in maintaining a low level of cell membrane permeability. Consequently, it can be concluded that chitosan could have a protective function against cell membrane damage in non-target mosses.

Influence of phytocenosis on the medical potential of moss extracts: the Pleurozium schreberi (Willd. ex Brid.) Mitt. case.

The question was asked "whether plant phytocenosis has an impact on the medical potential of the extracts from Pleurozium schreberi". Moss samples were collected from four different phytocoenoses: mixed forest (oak-pine forest), a forest tract in pine forest, 5-15-year-old pine forest and 50-year-old pine forest. Chemical composition of the extracts, antioxidative capacity (FRAP and ABTS·+ assays), as well as biological activities including cytotoxicity for the mouse fibroblasts L929 line (MTT reduction assay), biostatic/biocidal effect against selected bacteria and fungi (broth microdilution method followed by culture on solid media), and regenerative properties on human fibroblasts HFF-1 line (scratch assay) were tested. The conducted research clearly proves that phytocenosis determines the quality of moss extracts. The analyses showed that in every examined aspect the IV-7 extract (obtained from a specimen collected in a Pinus sylvestris L. forest, monoculture up to 15 years old) exhibited the highest values and the strongest activity. Other extracts of the same species but growing in other phytocenoses-in a mixed forest (IV-5), a forest tract in a Pinus sylvestris monoculture forest (IV-6) and in a P. sylvestris forest of pine monoculture about 50 years old (IV-8) showed much weaker activity and lower values of the above-mentioned parameters. At the same time, none of the tested extracts exerted a pro-regenerative effect. The P. schreberi extracts were characterized by a varied total content of phenolic compounds in the range from 0.63 ± 0.02 to 14.01 ± 0.25 mg/g of plant material. UPLC/MS analysis showed a varied phenolic profile of the extracts, with caffeoylquinic acid and quercetin triglucoside predominating in all of them.

Chemical Composition, Antitumor Properties, and Mechanism of the Essential Oil from Plagiomnium acutum T. Kop.

Plagiomnium acutum T. Kop. (P. acutum) has been used as a traditional Chinese medicine for thousands of years to treat cancer but lacks evidence. The objective of this work was to reveal the chemical composition of P. acutum essential oil (PEO) and explore its potential antitumor activity and molecular mechanism. PEO was prepared by the simultaneous distillation-extraction method and characterized by gas chromatography/mass spectroscopy. CCK8 assay, flow cytometry, western blot, and immunofluorescence techniques were used to analyze the effects and mechanism of PEO against cancer cells. A total of 74 constituents of PEO were identified, with diterpenes (26.5%), sesquiterpenes (23.89%), and alcohols (21.81%) being the major constituents. Two terpenoids, selina-6-en-4-ol and dolabella-3,7-dien-18-ol, were detected in PEO for the first time. PEO showed significant cell growth inhibitory activity on HepG2 and A549 cells by blocking the G1 phase and inducing apoptosis, which may be attributed to its upregulation of p21Cip1 and p27Kip1 proteins and interference with mitochondrial membrane potential effect. Dolabella-3,7-dien-18-ol accounts for 25.5% of PEO and is one of the main active components of PEO, with IC50 values in HepG2 and A549 cells of (25.820 ± 0.216) µg/mL and (23.597 ± 1.207) µg/mL, respectively. These results confirmed the antitumor medicinal value of P. acutum and showed great application potential in the pharmaceutical industry.

Vanadium Contamination in Soil and Atmospheric Deposition in Albania.

By examining and evaluating the vanadium content in topsoil and moss samples, this study sought to better understand vanadium contamination in soil and atmospheric deposition. In the research area, Hypnium cupressiforme sps. moss is used. According to different distribution patterns and the lack of a link between vanadium in moss and soil samples studied by correlation analysis, no interactions between substrate soil and moss samples were investigated. Maximum vanadium concentrations (13.2 mg/kg and 250 mg/kg, respectively) were found in both moss and soil samples near the Cu mineral-rich Gjegjan area. Using lithium-normalized data on vanadium, the effect of anthropogenic activity on the vanadium in moss and soil samples is examined. There were no relationships between concentration and normalized data in moss and soil samples, showing the simultaneous effects of natural and anthropogenic sources of vanadium in the research area. Country-specific trends revealed no change for vanadium since 2010 in Albania.

The specific glycerolipid composition is responsible for maintaining the membrane stability of Physcomitrella patens under dehydration stress.

Land colonization is a major event in plant evolution. Little is known about the evolutionary characteristics of lipids during this process. Here, we proved that Physcomitrella patens, a bryophyte that appeared in the early evolution of terrestrial plants, has short-term desiccation resistance. The maintenance of membrane integrity is related to its specific glycerolipid composition and key genes for lipid metabolism. We analyzed 414 types of lipid molecules, and found that phospholipids accounted for 61.7%, mainly PC and PI; glycolipids accounted for only 26.5%, with a special MGDG molecular map. The most abundant MDGD, that is, MGDG34:6, contained rare 15- and 19-carbon acyl chains; the level of neutral lipids was higher. This was consistent with the results observed by TEM, with fewer lamellae and obvious lipid droplets. Slight dehydration accumulated a large number of TAG molecules, and severe dehydration degraded phospholipids and caused membrane leakage, but PA and MGDG fluctuated less. The key genes of lipid metabolism, DGAT and PAP, were actively transcribed, suggesting that PA was one of the main DAG sources for TAG synthesis. This work proves that Physcomitrella patens adopts high-constitutive PC and PI similar to plant seeds, abundant TAG, and its own specific MGDG to resist extreme dehydration. This result provides a new insight into the lipid evolution of early terrestrial plants against unfavorable terrestrial environments.

Expression of a human cDNA in moss results in spliced mRNAs and fragmentary protein isoforms.

Production of biopharmaceuticals relies on the expression of mammalian cDNAs in host organisms. Here we show that the expression of a human cDNA in the moss Physcomitrium patens generates the expected full-length and four additional transcripts due to unexpected splicing. This mRNA splicing results in non-functional protein isoforms, cellular misallocation of the proteins and low product yields. We integrated these results together with the results of our analysis of all 32,926 protein-encoding Physcomitrella genes and their 87,533 annotated transcripts in a web application, physCO, for automatized optimization. A thus optimized cDNA results in about twelve times more protein, which correctly localizes to the ER. An analysis of codon preferences of different production hosts suggests that similar effects occur also in non-plant hosts. We anticipate that the use of our methodology will prevent so far undetected mRNA heterosplicing resulting in maximized functional protein amounts for basic biology and biotechnology.

Characterization of Trace Elements in Atmospheric Deposition Studied by Moss Biomonitoring in Georgia.

The present work was conducted to obtain and highlight the first comprehensive baseline data on atmospheric deposition of trace elements and to evaluate the air quality in Georgia. A total of 120 moss samples were collected over accessible territories in Georgia in the period from 2014 to 2017. Hylocomium splendens (Hedw.) Schimp., Hypnum cupressiforme (Hedw.), and Pleurozium schreberi (Brid.) Mitt. moss species were analyzed by two complementary analytical techniques: instrumental neutron activation analysis and atomic absorption spectrometry. Concentrations of 41 elements in mg/kg were determined. The concentrations were compared with the corresponding values in the literature and are in a good agreement, except for the concentration of Mg, Al, K, Ca, Ti, and Fe, which were higher than those reported for other countries. The principal component and discriminant analyses were implemented to extract information about the similar geochemical features and to decipher the provenance of the studied elements. The analysis showed that a considerable association of crustal elements and the provenance of elements can be considered as a mixture of geogenic and anthropogenic sources. In addition, the influence of different latitudinal climate zones on the distribution of elements in the atmospheric deposition was observed. The enrichment factor shows considerable values for Th and Zr. The spatial distribution of the pollution load index identifies four zones (#12, 38, 53, and 64). The potential ecological risk index and the risk index were calculated and it does not pose significant risk except As and Cd. The data obtained can be used as the first dataset of metal characterization of air pollution in Georgia.

Preferred crystallographic orientation of cellulose in plant primary cell walls.

Cellulose, the most abundant biopolymer on earth, is a versatile, energy rich material found in the cell walls of plants, bacteria, algae, and tunicates. It is well established that cellulose is crystalline, although the orientational order of cellulose crystallites normal to the plane of the cell wall has not been characterized. A preferred orientational alignment of cellulose crystals could be an important determinant of the mechanical properties of the cell wall and of cellulose-cellulose and cellulose-matrix interactions. Here, the crystalline structures of cellulose in primary cell walls of onion (Allium cepa), the model eudicot Arabidopsis (Arabidopsis thaliana), and moss (Physcomitrella patens) were examined through grazing incidence wide angle X-ray scattering (GIWAXS). We find that GIWAXS can decouple diffraction from cellulose and epicuticular wax crystals in cell walls. Pole figures constructed from a combination of GIWAXS and X-ray rocking scans reveal that cellulose crystals have a preferred crystallographic orientation with the (200) and (110)/([Formula: see text]) planes preferentially stacked parallel to the cell wall. This orientational ordering of cellulose crystals, termed texturing in materials science, represents a previously unreported measure of cellulose organization and contradicts the predominant hypothesis of twisting of microfibrils in plant primary cell walls.

The Moss Biomonitoring Method and Neutron Activation Analysis in Assessing Pollution by Trace Elements in Selected Polish National Parks.

The concentrations of trace elements in feather moss Pleurozium schreberi (Brid.) Mitt. were used to indicate the relative levels of air pollution by trace elements in Polish national parks. Pleurozium schreberi was collected from nine national parks. The highest concentrations were recorded in the moss samples from the southern and most industrialised part of the country; the lowest from northern and north-eastern Poland. A comparison of data obtained from Polish national parks in the 1970s and 1990s showed a significant decrease in the concentrations of heavy metals. In the linear covariability estimation, the t quantile approach was used for multi-element comparison. A number of positive covariabilities were observed. This is a result of anthropogenic activity and the geochemical characteristics of the local environment, including crust composition to which soil composition is related. The statistical approach of t quantile to study common relationships between element concentrations can be used in the interpretation of biomonitoring research results in similar studies.

Agarose/κ-carrageenan-based hydrogel film enriched with natural plant extracts for the treatment of cutaneous wounds.

Hydrogels for complex and chronic wound dressings must be conformable, absorb and retain wound exudates and maintain hydration. They can incorporate and release bioactive molecules that can accelerate the healing process. Wound dressings have to be in contact with the wound and epidermis, even for long periods, without causing adverse effects. Hydrogel dressing formulations based on biopolymers derived from terrestrial or marine flora can be relatively inexpensive and well tolerated. In the present article hydrogel films composed by agarose (1.0 wt%), κ-carrageenan at three different concentrations (0.5, 1.0 and 1.5 wt%) and glycerol (3.0 wt%) were prepared without recourse to crosslinking agents, and characterized for their mechanical properties, morphology, swelling and erosion behavior. The films resulted highly elastic and able to absorb and retain large amounts of fluids without losing their integrity. One of the films was loaded with the aqueous extract from Cryphaea heteromalla (Hedw.) D. Mohr for its antioxidant properties. Absence of cytotoxicity and ability to reduce the oxidative stress were demonstrated on NIH-3T3 fibroblast cell cultures. These results encourage further biological evaluations to assess their impact on the healing process.

Accurate prediction of species-specific 2-hydroxyisobutyrylation sites based on machine learning frameworks.

Lysine 2-hydroxyisobutyrylation (Khib) is a newly discovered post-translational modification (PTM) across eukaryotes and prokaryotes in recent years, which plays a significant role in diverse cellular functions. Accurate prediction of Khib sites is a first-crucial step to decipher its molecular mechanism and urgently needed. In this work, based on a large benchmark datasets in multi-species, a novel online species-specific prediction tool, namely KhibPred, was developed to identify Khib sites. Four types of feature strategies, including sequence-based information, physicochemical properties and evolutionary-derived information, were applied to represent a wide range of protein sequences, and the random forest was used to build the optimal feature datasets. Moreover, six representative machine learning (ML) methods were trained and comprehensively discussed and compared for each organism. Data analyses suggested that the unique protein sequence preferences were discovered for each species. When evaluated on independent test datasets, the area under the receiver operating characteristic curves (AUCs) achieved 0.807, 0.781, 0.825 and 0.831 for Saccharomyces cerevisiaes, Physcomitrella patens, Rice Seeds and HeLa cells, respectively. The satisfactory results imply that KhibPred is a promising computational tool. The online predictor can be freely available at: http://bioinfo.ncu.edu.cn/KhibPred.aspx.

Copper Content and Resistance Mechanisms in the Terrestrial Moss Ptychostomum capillare: A Case Study in an Abandoned Copper Mine in Central Spain.

We present a case study on the tissue absorption of copper of a widely distributed moss species, Ptychostomum capillare in the polluted soil of an abandoned copper mine in central Spain. We studied the soil properties in a copper soil pollution gradient and sampled the moss tufts growing on them in four plots with contrasted soil copper levels. We determined the copper content in the soil and in the moss tissues. On these moss samples, we also performed histochemical tests and X-ray dispersive spectrometry coupled with scanning electron microscopy (SEM-EDX), both in untreated shoots and in samples where surface waxes were removed. We checked the behavior of this species using a metallophillous moss, Scopelophila cataractae, for comparative purposes. Copper contents in P. capillare seem to depend more on available, rather than total soil copper contents. Our results indicate that this moss is able to concentrate 12-fold the available soil copper in soil with low available copper content, whereas in the most polluted soil the concentration of Cu in the moss was only half those levels. Both histochemical and SEM-EDX tests show no surface copper in the mosses from the least polluted plot, whereas in samples from the soil with highest copper content, the removal of surface waxes also reduces or removes copper from the moss shoots. Our observations point at a mixed strategy in P. capillare in this copper mine, with metal accumulation behavior in the lowest Cu plot, and an exclusion mechanism involving wax-like substances acting as a barrier in the most polluted plots. These distortions impede the estimation of environmental levels and thus compromise the value of this moss in biomonitoring. We highlight the need of extending these studies to other moss species, especially those used in biomonitoring programs.

The L motifs of two moss pentatricopeptide repeat proteins are involved in RNA editing but predominantly not in RNA recognition.

Pentatricopeptide repeat (PPR) proteins, composed of PPR motifs repeated in tandem, are sequence-specific RNA binding proteins. Recent bioinformatic studies have shown that the combination of polar amino acids at positions 5 and last in each PPR motif recognizes RNA bases, and an RNA recognition code for PPR proteins has been proposed. Subsequent studies confirmed that the P (canonical length) and S (short) motifs bind to specific nucleotides according to this code. However, the contribution of L (long) motifs to RNA recognition is mostly controversial, owing to the presence of a nonpolar amino acid at position 5. The PLS-class PPR protein PpPPR_56 is a mitochondrial RNA editing factor in the moss Physcomitrella patens. Here, we performed in vitro RNA binding and in vivo complementation assays with PpPPR_56 and its variants containing mutated L motifs to investigate their contributions to RNA recognition. In vitro RNA binding assay showed that the original combination of amino acids at positions 5 and last in the L motifs of PpPPR_56 is not required for RNA recognition. In addition, an in vivo complementation assay with RNA editing factors PpPPR_56 and PpPPR_78 revealed the importance of nonpolar amino acids at position 5 of C-terminal L motifs for efficient RNA editing. Our findings suggest that L motifs function as non-binding spacers, not as RNA-binding motifs, to facilitate the formation of a complex between PLS-class PPR protein and RNA. As a result, the DYW domain, a putative catalytic deaminase responsible for C-to-U RNA editing, is correctly placed in proximity to C, which is to be edited.

DIX Domain Polymerization Drives Assembly of Plant Cell Polarity Complexes.

Cell polarity is fundamental for tissue morphogenesis in multicellular organisms. Plants and animals evolved multicellularity independently, and it is unknown whether their polarity systems are derived from a single-celled ancestor. Planar polarity in animals is conferred by Wnt signaling, an ancient signaling pathway transduced by Dishevelled, which assembles signalosomes by dynamic head-to-tail DIX domain polymerization. In contrast, polarity-determining pathways in plants are elusive. We recently discovered Arabidopsis SOSEKI proteins, which exhibit polar localization throughout development. Here, we identify SOSEKI as ancient polar proteins across land plants. Concentration-dependent polymerization via a bona fide DIX domain allows these to recruit ANGUSTIFOLIA to polar sites, similar to the polymerization-dependent recruitment of signaling effectors by Dishevelled. Cross-kingdom domain swaps reveal functional equivalence of animal and plant DIX domains. We trace DIX domains to unicellular eukaryotes and thus show that DIX-dependent polymerization is an ancient mechanism conserved between kingdoms and central to polarity proteins.

Investigations of the Atmospheric Deposition of Major and Trace Elements in Western Tajikistan by Using the Hylocomium splendens Moss as Bioindicators.

The study was performed in a mountainous area of approximately 7000 sq. km of Western Tajikistan, i.e., Turkestan, Zeravshan, Hissar, and Karateghin ridges that are characterized by complex geological settings. Moss biomonitoring was used to assess the concentration level of trace and major elements in atmospheric deposition of the study area. Hylocomium splendens (Hedw.) Schimp. moss was used as biomonitor in this study. 43 major and trace-elements were determined by Epithermal Neutron Activation (ENAA) and Atomic Absorption Spectrometry (AAS). GIS maps of the 43 elements showed that the distribution of Mo, Cd, REE, Th, and U could be most probably associated with the Odjuk pegmatite field. Zr, Hf, and W contents are significantly increased in the vicinity of the Sarbo River washout while Cr, Co, Ni, and As showed a maximum content near Kanchoch gold field. The global pollution index based on the local content of presumed pollutants Cr, Ni, Cu, Zn, As, Cd, Sb, and Pb in some places exceeded the threshold limits for a pristine, unpolluted environment. At the same time, the distribution of incompatible Sc, La, Yb, and Th suggested for the airborne material deposited on mosses a continental component, enriched in few places in felsic components.

A first insight into the estimation of uncertainty associated with storage and physical preparation of forest moss samples for trace element analysis.

To assess the level of uncertainty related to storage and physical preparation, 27 combined samples of moss species Pleurozium schreberi (Brid.) Mitt and their duplicates were collected within three forest areas. Each sample was divided into three sub-samples subjected to further treatment: D - drying (20-25 °C), F - freezing (-20 °C), and A - acclimatization (4 °C). After 7 days, all the samples were split into two sub-samples for physical preparation, dry (P1) and wet (P2) cleaning, respectively. Subsequently, the samples were milled, digested in a closed microwave system and analysed for Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn using the flame (FAAS) and graphite furnace (GFAAS) atomic absorption spectrometry. In four out of eight metals (Cu, Fe, Mn, Ni), the lowest mean values were in the samples stored at -20 °C, however, in two cases (Cd, Pb), the acclimatization procedure also led to lower concentrations. Except for Mn and Zn, the higher contents of elements were found in samples that were dry cleaned after storage. The level of sample storage uncertainty (srstor) varied from 4.8% to 24.0%. The uncertainty related to preparation was in the range of 3.0-21.0%. Only for Co, the contribution of srstor uncertainty to the budget of uncertainty was lower than that from physical preparation. For the other elements, this contribution was at a similar level (Ni, Zn) or higher (Cd, Cu, Fe, Mn, Pb). In most cases, the lower srprep values were obtained when the samples were dry cleaned after storage, regardless of the storage conditions.

Evaluation of the acute toxicity, phototoxicity and embryotoxicity of a residual aqueous fraction from extract of the Antarctic moss Sanionia uncinata.

BACKGROUND: Ultraviolet (UV) radiation is the main exogenous inductor of skin damage and so photoprotection is important to control skin disorders. The Antarctic moss Sanionia uncinata is an important source of antioxidants and the photoprotective activity of its organic extracts has been investigated. This study aimed to evaluate the potential photoprotection, cytotoxicity and embryotoxicity of residual aqueous fraction (AF) from the moss S. uncinata. METHODS: UV-visible spectrum and SPF (sun protection factor) were determined by spectrophotometry. Embryotoxicity potential was evaluated by Fish embryo-larval toxicity test using zebrafish (Danio rerio) as organism model. Cell death assays by water-soluble tetrazolium salt (WST-1) and lactate dehydrogenase (LDH) were investigated using HaCaT keratinocyte cell line cultured in monolayers and three dimensions (3D). Phototoxicity and association with UV-filters were performed by 3T3 neutral red uptake test. RESULTS: The AF showed sharp absorption bands in the UV region and less pronounced in the visible region. The SPF was low (2.5 ± 0.3), but the SPF values of benzophenone-3 and octyl-methoxycinnamate increased ~ 3 and 4 times more, respectively, in association with AF. The AF did not induce significant lethal and sublethal effects on zebrafish early-life stages. In monolayers, the HaCaT cell viability, evaluated by WST-1, was above 70% by ≤0.4 mg AF/mL after 48 and 72-h exposure, whereas ≤1 mg AF/mL after 24-h exposure. The LDH assay showed that the cell viability was above 70% by ≤0.4 mg AF/mL even after 72-h exposure, but ≤1 mg/mL after 24 and 48-h exposure. In 3D cell culture, an increased cell resistance to toxicity was observed, because cell viability of HaCaT cell by WST-1 and LDH was above ~ 90% when using ≤1 and 4 mg AF/mL, respectively. The AF demonstrated values of photo irritation factor < 2 and of photo effect < 0.1, even though in association with UV-filters. CONCLUSIONS: The residual AF absorbs UV-vis spectrum, increased SPF values of BP-3 and OMC and does not induce embryotoxicity to zebrafish early life-stage. The cell death assays allowed establishing non-toxic doses of AF and phototoxicity was not detected. AF of S. uncinata presents a good potential for skin photoprotection against UV-radiation.