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The sub-Antarctic Magellan Ecoregion is a unique biogeographic area located at the southern tip of South America, which has exceptional marine flora and high endemism. Along the coastline, the ochrophytes Macrocystis pyrifera and Lessonia flavicans form vital underwater forests that serve as critical habitats, providing shelter, food and breeding grounds for a diverse marine organisms. These algal species are also important components used in the food industry and biomedicine, due to their high lipid, amino acid and fiber content. In this study, we investigated the intra-thallus variation of fatty acids among the different morphological structures (fronds, stipes and holdfast) of M. pyrifera and L. flavicans collected in Rinconada Bulnes during spring, 2021. The stipes of M. pyrifera (3.73 ± 1.73%) and the fronds of L. flavicans (3.35 ± 0.97%) both exhibited high lipid content. Saturated fatty acids were highest in the holdfast of M. pyrifera (37.82 ± 0.06%) followed by the fronds of L. flavicans (34.30 ± 0.10%). Notably, monounsaturated fatty acids showed higher levels en the holdfast of L. flavicans (46.45 ± 0.19%) followed by the stipes of M. pyrifera (43.04 ± 0.08%). The fronds of both M. pyrifera (32.38 ± 0.26%) and L. flavicans (28.89 ± 0.23%) showed high levels of polyunsaturated fatty acids. These findings provide valuable insight into the intra-thallus variation of fatty acids in different morphological structures of M. pyrifera and L. flavicans, highlighting their potential nutritional and biomedical importance as the most representative kelps in the Magellan region.

For over 140 years, lichens have been regarded as a symbiosis between a single fungus, usually an ascomycete, and a photosynthesizing partner. Other fungi have long been known to occur as occasional parasites or endophytes, but the one lichen–one fungus paradigm has seldom been questioned. Here we show that many common lichens are composed of the known ascomycete, the photosynthesizing partner, and, unexpectedly, specific basidiomycete yeasts. These yeasts are embedded in the cortex, and their abundance correlates with previously unexplained variations in phenotype. Basidiomycete lineages maintain close associations with specific lichen species over large geographical distances and have been found on six continents. The structurally important lichen cortex, long treated as a zone of differentiated ascomycete cells, appears to consistently contain two unrelated fungi.

We investigated the influence of availability as well as type of organic substrate on the growth of the cyanolichen Peltigera membranacea. A total of 145 lichen lobes were grown in a plant growth chamber for 28 days. Of these, 73 were kept in permanent darkness and another 72 were exposed to a diurnal light-dark cycle. A third of the lobes from both treatments were grown on pulverized leaf litter, the second third on pulverized bryophytes, and the remainder were grown without an organic substrate to serve as a control group. Growth was quantified via relative growth rate, relative thallus area growth rate, and changes in specific thallus mass. The lobes kept in a diurnal light-dark cycle showed higher growth rates than those kept in darkness, as is expected for an organism that obtains its carbon from its photoautotrophic symbiosis partner. Furthermore, growth rates were higher in lobes growing on organic substrates. The results show that the availability of an organic substrate positively affects lichen growth in a growth cabinet. Leaf litter led to a higher biomass gain in lichen lobes, whereas area gain was unrelated to substrate type.

On the territory of the Kivach State Nature Reserve (Northwestern Russia, Republic of Karelia) in the supralittoral conditions of the banks of the Suna River, the growth characteristics of three epilithic lichen species, Bellemerea alpina, Lecidea lapicida, and Protoparmeliopsis muralis, were studied. Data were analyzed over an 11-year follow-up period. For each thallus studied, a growth model was created using regression analysis, which reflects the dependence of the area of the thallus on the year of measurement and makes it possible to estimate the age of the thalli. Data were obtained on the size (cm 2 ), growth rate (cm 2 /year), and age (years) of thalli. For these signs, the confidence interval of the means and the confidence interval of possible values were estimated at a probability of P = 95%.

Microorganisms play important roles in the growth and development of macroalgae. Still, the biodiversity of the epiphytic microbial community associated with the economically important red alga Pyropia haitanensis during the cultivation period remains uncharacterized, especially the effects of P. haitanensis cultivation on the microbial community of surrounding seawater. Here, we isolated epiphytic microbes from P. haitanensis during the thallus stage during oceanic cultivation and the conchocelis stage during industrial cultivation. The dynamic diversity patterns, as determined by 16S and 18S rRNA gene sequencing of the bacterial and fungal communities, respectively, associated with P. haitanensis and seawater in the presence and absence of algal cultivation were investigated. A notable distinction was observed between the microbial communities of seawater with and without P. haitanensis cultivation. Additionally, the alpha-diversity of seawater with P. haitanensis cultivation was significantly greater than without P. haitanensis cultivation. Cyanobacteria were the dominant species in the latter, while Rhodobacteraceae was enriched in the former. Furthermore, there were significant differences in the microbial community of P. haitanensis at the thallus and conchocelis stages. Seawater properties had significant direct effects on the microbial diversity of P. haitanensis and cultivation seawater, but not on non-cultivation seawater. The enriched microbial presence might promote thallus morphogenesis and be beneficial for the growth and development of both the thallus and conchocelis stages. These findings expand our knowledge of the bacteria and fungi that are beneficial for Pyropia nursery seeding and cultivation, as well as the effects of P. haitanensis cultivation on the seawater microbial community.

The work presents a new spectrophotometric method of determining iodine inorganic forms in the kelp thalli (Laminariae thalli). A glycerin-stabilized starch solution was used as a coloring reagent. The developed method is characterized by ease of implementation, high selectivity and sensitivity (at the ng/ml level) as opposed to available methods in the literature. High stability of the analytical signal, linearity in the range from 60 to 720 ng/ml, accuracy, repeatability, and intermediate precision were established by research of metrological characteristics. The detection limit and quantification limit in solutions obtained after sample preparation were 20 and 60ng/ml. The proposed methodology may be recommended for research as well as in regulatory documentation for crude herbal drug (CHD).

The evolution of complex multicellularity has been one of the major transitions in the history of life. In contrast to simple multicellular aggregates of cells, it has evolved only in a handful of lineages, including animals, embryophytes, red and brown algae, and fungi. Despite being a key step toward the evolution of complex organisms, the evolutionary origins and the genetic underpinnings of complex multicellularity are incompletely known. The development of fungal fruiting bodies from a hyphal thallus represents a transition from simple to complex multicellularity that is inducible under laboratory conditions. We constructed a reference atlas of mushroom formation based on developmental transcriptome data of six species and comparisons of >200 whole genomes, to elucidate the core genetic program of complex multicellularity and fruiting body development in mushroom-forming fungi (Agaricomycetes). Nearly 300 conserved gene families and >70 functional groups contained developmentally regulated genes from five to six species, covering functions related to fungal cell wall remodeling, targeted protein degradation, signal transduction, adhesion, and small secreted proteins (including effector-like orphan genes). Several of these families, including F-box proteins, expansin-like proteins, protein kinases, and transcription factors, showed expansions in Agaricomycetes, many of which convergently expanded in multicellular plants and/or animals too, reflecting convergent solutions to genetic hurdles imposed by complex multicellularity among independently evolved lineages. This study provides an entry point to studying mushroom development and complex multicellularity in one of the largest clades of complex eukaryotic organisms.

Lichens are extremophilic symbiotic associations possessing phenomenal resistance to abiotic stress-factors. In this regard, melanization of thalli in response to UV is one of the mechanisms protecting lichens from excessive insolation. However, microstructure and biochemical properties of the melanized thalli are still poorly investigated. In the present study, morphological, nanomechanical, and physiological, and biochemical traits of naturally melanized thalli of the Cetraria islandica (L.) Ach. lichen were examined. In the upper cortex of its thallus, the nature of the pigment layer was verified using typical qualitative reactions for melanins. It was found that melanization leads to changes in microstructure of the upper cortex of the mycobiont, in particular, thickening of the cell walls and extension of the interhyphal space. The melanized and pale (nonmelanized) thalli were found to differ from each other in their nanomechanical properties, including the parameters of adhesion and rigidity. This implies the possible formation of complex associates of melanin with cell wall components in the melanized mycobiont. In addition, higher antioxidant activity and lower respiratory activity were found in the melanized thalli of C. islandica in comparison with the pale thalli. Presumably, the found modifications in the microstructure and nanomechanical, physiological, and biochemical properties of thalli occurring in the course of melanization make lichens more resistant to intense insolation.

Circinaria russus sp. nov. is described based on morpho–anatomical and phylogenetic analysis. The novel species is characterized by its reddish brown thallus, absence of marginal lobes, taller hymenium 175–190 µm, and larger ascospores 22–32 × 15–20 than the similar taxon Circinaria tortuosa. A phylogenetic analysis, based on ITS nrDNA sequencing and ML analysis, supported the separation of the novel species. Complete description and a comparative analysis with related Circinaria species are provided.

The ~1.6 Ga Tirohan Dolomite of the Lower Vindhyan in central India contains phosphatized stromatolitic microbialites. We report from there uniquely well-preserved fossils interpreted as probable crown-group rhodophytes (red algae). The filamentous form Rafatazmia chitrakootensis n. gen, n. sp. has uniserial rows of large cells and grows through diffusely distributed septation. Each cell has a centrally suspended, conspicuous rhomboidal disk interpreted as a pyrenoid. The septa between the cells have central structures that may represent pit connections and pit plugs. Another filamentous form, Denaricion mendax n. gen., n. sp., has coin-like cells reminiscent of those in large sulfur-oxidizing bacteria but much more recalcitrant than the liquid-vacuole-filled cells of the latter. There are also resemblances with oscillatoriacean cyanobacteria, although cell volumes in the latter are much smaller. The wider affinities of Denaricion are uncertain. Ramathallus lobatus n. gen., n. sp. is a lobate sessile alga with pseudoparenchymatous thallus, \"cell fountains,\" and apical growth, suggesting florideophycean affinity. If these inferences are correct, Rafatazmia and Ramathallus represent crown-group multicellular rhodophytes, antedating the oldest previously accepted red alga in the fossil record by about 400 million years.