A New Signal of Tropicalization in the Northeast Atlantic: The Spread of the Spotfin Burrfish Chilomycterus reticulatus in Madeira Archipelago and Its Invasion Risk

Current trends in the global climate facilitate the displacement of numerous marine species from their native distribution ranges to higher latitudes when facing warming conditions. In this work, we analyzed occurrences of a circumtropical reef fish, the spotfin burrfish, Chilomycterus reticulatus (Linnaeus, 1958), in the Madeira Archipelago (NE Atlantic) between 1898 and 2021. In addition to available data sources, we performed an online survey to assess the distribution and presence of this species in the Madeira Archipelago, along with other relevant information, such as size class and year of the first sighting. In total, 28 valid participants responded to the online survey, georeferencing 119 C. reticulatus sightings and confirming its presence in all archipelago islands. The invasiveness of the species was screened using the Aquatic Species Invasiveness Screening Kit. Five assessments rated the fish as being of medium risk of establishing a local population and becoming invasive. Current temperature trends might have facilitated multiple sightings of this thermophilic species in the Madeira Archipelago. The present study indicates an increase in C. reticulatus sightings in the region. This underlines the need for updated comprehensive information on species diversity and distribution to support informed management and decisions. The spread of yet another thermophilic species in Madeiran waters provides further evidence of an ongoing tropicalization, emphasizing the need for monitoring programs and the potential of citizen science in complementing such programs.

To graze or to mow? The influence of grassland management on grasshoppers (Orthoptera) on a flood protection embankment in the Donau-Auen National Park (Austria)

Introduction Most Central European grasslands crucially depend on land use, and thus there is a need to comparatively analyse the impacts of different types of land use management on grassland biota. Aims and methods We use grasshoppers (Orthoptera), which are the most important insect herbivores in grasslands, and assess the differences of grazing (sheep) and mowing on species abundance, richness, and composition. We use a river embankment in the National Park Donau Auen as study site, where we have established 28 transects. Orthoptera abundance was surveyed 13 times between May and September 2019 in each transect. Results We recorded 24 Orthoptera species, of which 12 species are listed in the national Red List. The most abundant non-threatened species is Pseudochorthippus parallelus in mown transects, while in grazed transects Euchorthippus declivus is most abundant. Eight of the ten most abundant Orthoptera species differed significantly in abundance between mown and grazed transects. Total abundance of Orthoptera was higher in mown transects, while grazed transects had higher species richness. Most xero-thermophilic species were more abundant in grazed transects, while some species of mesic grassland were more abundant in mown transects. These species-level differences resulted in clearly separated Orthoptera species assemblages between grazed and mown transects. Our findings suggest that the less dense vegetation in grazed transects better fulfilled the habitat requirements of xero-thermophilic species compared to mown transects Discussion Given that mown and grazed transects are located adjacent to each other, that the complete study site was mown for many decades and grazing was only started one year before field data collection, the scale of differences in species richness, composition and abundances between grazed and mown transects is surprising. Thus, our findings indicate that grasshoppers respond rapidly to changing land use. Implications for insect conservation We conclude that river embankments can be important secondary habitats for species-rich grasshopper communities. We recommend that grazing should be continued at the river embankment, ideally as rotational pasture as currently done. Mowing should be changed towards mowing parts of the river embankment at different times and leaving small strips of vegetation unmown.

Northward Spread of the Parrotfish Sparisoma cretense (Teleostei: Scaridae) in the Mediterranean Sea: An Update on Current Distribution with Two New Records from Sardinia

The parrotfish Sparisoma cretense, a marine species native to the eastern and southern coastal areas of the Mediterranean, has extended its distribution northward. Here, we provide an update on its distribution based on currently published data and two new records from the coastline of Sardinia, Italy (central-western Mediterranean). The survey methods were scuba diving and spearfishing: one specimen of S. cretense was caught along the Argentiera coastline (northwest Mediterranean) and the others were photographed in the Gulf of Orosei, Osalla Bay (central-eastern Mediterranean). A literature update, together with new records, documents the distribution of this species in the northernmost areas of the Mediterranean. Probably a result of global warming, the ongoing northward expansion of S. cretense highlights the need for sampling campaigns to obtain timely updates on population and distribution of this thermophilic species.

The First Insight into Polyhydroxyalkanoates Accumulation in Multi-Extremophilic Rubrobacter xylanophilus and Rubrobacter spartanus

Actinobacteria belonging to the genus Rubrobacter are known for their multi-extremophilic growth conditions—they are highly radiation-resistant, halotolerant, thermotolerant or even thermophilic. This work demonstrates that the members of the genus are capable of accumulating polyhydroxyalkanoates (PHA) since PHA-related genes are widely distributed among Rubrobacter spp. whose complete genome sequences are available in public databases. Interestingly, all Rubrobacter strains possess both class I and class III synthases (PhaC). We have experimentally investigated the PHA accumulation in two thermophilic species, R. xylanophilus and R. spartanus. The PHA content in both strains reached up to 50% of the cell dry mass, both bacteria were able to accumulate PHA consisting of 3-hydroxybutyrate and 3-hydroxyvalerate monomeric units, none other monomers were incorporated into the polymer chain. The capability of PHA accumulation likely contributes to the multi-extremophilic characteristics since it is known that PHA substantially enhances the stress robustness of bacteria. Hence, PHA can be considered as extremolytes enabling adaptation to extreme conditions. Furthermore, due to the high PHA content in biomass, a wide range of utilizable substrates, Gram-stain positivity, and thermophilic features, the Rubrobacter species, in particular Rubrobacter xylanophilus, could be also interesting candidates for industrial production of PHA within the concept of Next-Generation Industrial Biotechnology.

Effect of Low Temperature on Germination, Growth, and Seed Yield of Four Soybean (Glycine max L.) Cultivars

During germination at low temperatures, seeds rich in proteins may experience damage to their cytoplasmic membranes. The study aimed to investigate the influence of the germination temperature on growth, development, and yield of four cultivars of soybean, a typical thermophilic species. The seeds were germinated at 10, 15, and 25 °C in the dark. After 48 h, one part of the seeds was analyzed for their amylase and dehydrogenase activity, cell membrane permeability, and germination vigor. The other part was transferred into soil and cultivated up to yielding. Chlorophyll fluorescence, fresh (FW) and dry weight (DW) of shoots, pod and seed number, and seed DW were analyzed. The plants of cvs. ‘Abelina’, ‘Malaga’, and ‘Merlin’, germinating at low temperature, produced the highest number of seeds. Seed number negatively correlated with their DW and positively with the number of active reaction centers (RC/CSm) in all cultivars. In cvs. ‘Abelina’ and ‘Malaga’, the number of seeds also positively correlated with the index performance of photosystem II (PSII), which was the highest in all plants germinating at low temperature. We suggest cultivating cv. ‘Abelina’ in cooler regions, while cvs. ‘Petrina’ and ‘Malaga’ in warmer areas.

A Novel Thermostable Keratinase from Deinococcus geothermalis with Potential Application in Feather Degradation

Keratinase can specifically attack disulfide bridges in keratin to convert them from complex to simplified forms. Keratinase thermal stability has drawn attention to various biotechnological industries. In this study, a keratinase DgeKer was identified from a slightly thermophilic species, D. geothermalis. The in silico analysis showed that DgeKer is composed of signal peptide, N-terminal propeptide, mature domain, and C-terminal extension. DgeKer and its C-terminal extension-truncated enzyme (DgeKer-C) were cloned and expressed in E. coli. The purified DgeKer and DgeKer-C showed maximum activity at 70 °C and pH 9–The thermal stability assay (60 °C) showed that the half-life value of DgeKer and DgeKer-C were 103.45 min and 169.10 min, respectively. DgeKer and DgeKer-C were stable at the range of pH from 9 to 11 and showed good tolerance to some metal ions, surfactants and organic solvent. Furthermore, DgeKer could degrade feathers at 70 °C for 60 min. However, the medium became turbid with obvious softening of barbules after being treated with DgeKer-C, which might be due to C-terminal extension. In summary, a thermostable keratinase DgeKer with high efficiency degradation of feathers may have great potential in industry.

Molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis

Over the last decade, increasing attention has been paid to the molecular adaptations used by organisms to cope with thermal stress. However, to date, few studies have focused on thermophilic species living in hot, arid climates. In this study, we explored molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis, one of the world’s most thermotolerant animal taxa. We compared heat tolerance and gene expression patterns across six phylogenetically distant species that live in different habitats and experience different thermal regimes. We found that all six species had similar heat tolerance levels and critical thermal maxima. Furthermore, the transcriptome analyses revealed that, although the number of differentially expressed genes varied widely for the 6 species (from 54 to 1,118), many were also shared. Functional annotation of the differentially expressed and co-expressed genes then showed that the biological pathways involved in heat-shock responses were similar among species and were associated with four major processes: the regulation of transcriptional machinery and DNA metabolism; the preservation of proteome stability; the elimination of toxic residues; and the maintenance of cellular integrity. Overall, our results suggest that molecular responses to heat stress have been evolutionarily conserved in the ant genus Cataglyphis and that their versatility may help workers withstand temperatures close to their physiological limits.

Temperature adaptations of the thermophilic snail Echinolittorina malaccana: insights from metabolomic analysis

The periwinkle snail Echinolittorina malaccana, whose upper lethal temperature is near 55°C, is one of the most heat-tolerant eukaryotes known. We conducted a multi-level investigation, including cardiac physiology, enzyme activity, and targeted and untargeted metabolomic analysis, that elucidated a spectrum of adaptations to extreme heat. All systems examined showed heat intensity-dependent responses. Under moderate heat stress (from 37 to 45°C) the snail depressed cardiac activity and entered a state of metabolic depression. The global metabolomic analyses and enzymatic analysis showed that the depressed metabolic state under moderate heat stress entailed production of metabolites characteristic of oxygen-independent pathways of ATP generation (lactate and succinate), which suggests that anaerobic metabolism was the main energy supply pathway under heat stress (from 37 to 52°C). The metabolomic analyses also revealed alterations in glycerophospholipid metabolism under extreme heat stress of 52°C, which likely reflected adaptive changes to maintain membrane structure. Small molecular mass organic osmolytes (glycine betaine, choline, and carnitine) showed complex changes in concentration that were consistent with a role of these protein-stabilizing solutes in protection of the proteome under heat stress. This thermophilic species thus can deploy a wide array of adaptive strategies to acclimatize to extremely high temperatures.

LENGTH-WEIGHT STRUCTURES AND FECUNDITY OF ANADROMOUS MASU SALMON (ONCORHYNCHUS MASOU) FROM WESTERN KAMCHATKA

Masu salmon Oncorhynchus masou is the most thermophilic species among the Pacific salmon, and Kamchat-ka peninsula is the northern border of its distribution. Due to small abundance, the biology of this species on the peninsula is poorly studied. Regular scientific researches of Masu salmon in Kamchatka have been con-ducted since 2009. The length-weight structures and fecundity of mature Masu salmon have been analyzed in several streams on western Kamchatka over a 10-year period (from 2009 to 2018) and present time. It has been established that the length, weight and fecundity of mature fish are different in the rivers of the peninsula. A tendency of increasing the biological characteristic of the species in recent years has been noted.