Marine Life Science & Technology最新文献

Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora. The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insufficiency of molecular data. With morphological and multi-gene-based molecular data presented here, the evolutionary phylogeny of several Scuticociliatia taxa that were hitherto especially poorly defined is analyzed and discussed. The results indicate: (1) all scuticociliates cluster into two well supported and one poorly supported group, representing three order-level taxa; (2) with the support of both morphological and molecular data, a new family Homalogastridae fam. nov. is proposed in the order Philasterida; (3) Parauronema is formally transferred to Uronematidae and Potomacus is treated as incertae sedis in the order Philasterida, therefore Parauronematidae is proposed to be a junior synonym of Uronematidae; (4) the genus Madsenia and the species Parauronema longum and Pseudocyclidium longum are treated as incertae sedis, while the genus Protophyra should be maintained in the family Ancistridae. In addition, the putative secondary structure of internal transcribed spacer 2 (ITS2) of representative taxa from the three orders of Scuticociliatia are analyzed, and consensus structures and nucleotide composition in each order are exhibited.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00264-8.

CO₂ concentration mechanisms (CCMs) are important in maintaining the high efficiency of photosynthesis of marine algae. Aquatic photoautotrophs have two types of CCMs: biophysical CCMs, based on the conversion of inorganic carbon, and biochemical CCMs, based on the formation of C₄ acid intermediates. However, the contribution of biophysical and biochemical CCMs to algal carbon fixation remains unclear. Here, we used ethoxyzolamide (EZ) inhibitors of carbonic anhydrase and 3-mercaptopicolinic acid (MPA) inhibitors for phosphoenolpyruvate carboxykinase to examine the importance of biophysical and biochemical CCMs in photosynthesis of the green macroalga Ulva prolifera. The culture experiments showed that the carbon fixation of the species declined when EZ inhibited the biophysical CCM, while the increase in cyclic electron flow around the photosystem I indicated a more active biochemical CCM, contributing to ~ 50% of total carbon fixation. The biophysical CCM was also reinforced when MPA inhibited the biochemical CCM. In a comparison, the biophysical CCM can compensate for almost 100% of total carbon fixation. The results indicate that biophysical CCMs dominate the process of carbon fixation of U. prolifera while biochemical CCM plays a supporting role. Our results provide evidence of a complementary coordination mechanism between the biophysical and biochemical CCMs that promotes the efficiency of photosynthesis of U. prolifera, an efficient mechanism to boost the alga's bloom.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00265-7.

[This corrects the article DOI: 10.1007/s42995-024-00229-x.].

Kelps are pivotal to temperate coastal ecosystems, providing essential habitat and nutrients for diverse marine life, and significantly enhancing local biodiversity. The impacts of elevated CO₂ levels on kelps may induce far-reaching effects throughout the marine food web, with potential consequences for biodiversity and ecosystem functions. This study considers the kelp Macrocystis pyrifera and its symbiotic microorganisms as a holistic functional unit (holobiont) to examine their collective response to heightened CO₂ levels. Over a 4 month cultivation from the fertilization of M. pyrifera gametes to the development of juvenile sporophytes, our findings reveal that elevated CO₂ levels influence the structure of the M. pyrifera symbiotic microbiome, alter metabolic profiles, and reshape microbe-metabolite interactions using 16S rRNA amplicon sequencing and liquid chromatography coupled to mass spectrometry analysis. Notably, Dinoroseobacter, Sulfitobacter, Methylotenera, Hyphomonas, Milano-WF1B-44 and Methylophaga were selected as microbiome biomarkers, which showed significant increases in comparative abundance with elevated CO₂ levels. Stress-response molecules including fatty-acid metabolites, oxylipins, and hormone-like compounds such as methyl jasmonate and prostaglandin F2a emerged as critical metabolomic indicators. We propose that elevated CO₂ puts certain stress on the M. pyrifera holobiont, prompting the release of these stress-response molecules. Moreover, these molecules may aid the kelp's adaptation by modulating the microbial community structure, particularly influencing potential pathogenic bacteria, to cope with environmental change. These results will enrich the baseline data related to the chemical interactions between the microbiota and M. pyrifera and provide clues for predicting the resilience of kelps to future climate change.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00259-5.

Understanding the potential areas suitable for offshore mariculture is crucial to global seafood security. Here, we map the potential global offshore mariculture areas for 23 principal commercial finfish using an ensemble model. The model involves the temporal-spatial heterogeneity of environments and constraints of temperature-dependent hypoxia and cold edges of cultured finfish by metabolic index and lower thermal safety margin, respectively. Our results show that currently, there is 9.16 ± 1.22 million km² of potentially suitable area for offshore finfish mariculture. Under climate change, the potential suitable area will be reduced to between 86.7% and 91.7% of the current size by 2050. Compared to the decline in tropical regions, the expanded potential areas in temperate and polar regions will become more important for global seafood security. The potential offshore finfish mariculture area responds differently to global change among species, and cold-water finfish may benefit from global warming. Overall, despite changes in the distribution of global offshore mariculture areas and replacements of local potential mariculture species, offshore finfish mariculture still holds immense potential in the future.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00257-7.

The genus Callistoctopus comprises 13 species, and has been reported mostly in the Western Pacific Ocean. Here, we described three new species from China, Ca. paucilamellus sp. nov., Ca. sparsus sp. nov., and Ca. gracilis sp. nov., based on morphometric and meristic characteristics. The diagnoses, descriptions and detailed morphometric data are provided for each species. The cytochrome c oxidase I (COI) genes of the three new species are sequenced, and compared with related species and analyzed for their systematic positions. Both phylogenetic trees constructed using three mitochondrial genes (12S rRNA, 16S rRNA, COI) and one nuclear gene (Rhodopsin) revealed that our new species formed into two distinct clades with strong support values. One clade included Ca. gracilis sp. nov., Ca. sp. 1, Ca. xiaohongxu, Ca. tenuipes and Ca. paucilamellus sp. nov., which clustered together. The other clade showed that Ca. sparsus sp. nov. was closely related to Ca. sp. 2 and Ca. sp. 3. Ca. luteus and Ca. macropus were located at the base of the Callistoctopus group. Based on our integrative studies, both morphological and molecular evidence suggested strongly that O. minor is more likely to be classified as a species of Callistoctopus. Morphological comparisons were made between the three new species and related taxa, which could be recognized based on the 7-8 gill lamellae of each demibranch, numerous small black spots on the subdermal layer of the arms, and an elongated body.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00258-6.

Bacterial community play an essential role in regulating water quality and the global biogeochemical cycle in aquatic ecosystems. However, how trophic interactions (i.e., biotic factors) regulate the diversity and composition of bacterial community in lake ecosystems remains unknown. Here, we employed DNA meta-barcoding of water samples to explore the impact of bacterivorous protozoans on the bacterial community. The results showed significant seasonal variations in the diversity and composition of both bacterial and protist communities. The composition of bacterivorous protozoans was identified as the primary predictor for the bacterial community alpha diversity in spring and summer, and for beta diversity in spring and autumn, indicating that biotic interactions play a greater role in driving the diversity of bacterial community across different seasons. Biological factors were more important than environmental factors for explaining the variations in the relative abundance of several bacterial genera (i.e., Pseudoxanthomonas, hgcI_clade, and Pseudorhodobacter). Network analyses showed that bacterial networks differed among seasons, and the autumn network exhibited the highest stability. Our findings indicated that the bacterial community stability was significantly affected by environmental factors, specifically SO₄ ^2-and PO₄ ^3-, rather than bacterivorous protozoans. Overall, our findings provide new perspectives on the role of trophic interactions in maintaining the structure of bacterial community in different seasons, and enhance our understanding of the bacterial community assembly in lake ecosystems.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00256-8.

[This corrects the article DOI: 10.1007/s42995-024-00248-8.].

Obesity has become a worldwide health problem. Seeking natural products with anti-obesity activity from lots of fungi has drawn the attention of pharmacologists. In our study, dipenipenoids A and B (1 and 2), the first dimeric indole-diterpenoids with a rare C-20-C-22' linkage, and their monomers (3 and 4), were isolated from a marine-derived Penicillium sp. CF-06 fungus from Suaeda salsa. The absolute configurations of 1-3 were assigned by the calculated TDDFT ECD method. The structure of 4 was verified by a single-crystal X-ray diffraction method for the first time. Interestingly, 1 and 2 displayed significant effects on the differentiation of 3T3-L1 adipocytes by down-regulating the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα) proteins, while monomers 3 and 4 exhibited no activity. Molecular docking results explained the mechanism that the interaction between dimer 1 and PPARγ was stronger than that between monomer 3 and PPARγ. Our research could provide new insight for the discovery of anti-obesity drugs.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00253-x.

Estuaries are usually characterized by strong spatial and temporal variability in water physicochemical conditions and are often largely affected by human activities. One important source of variability is caused by tides that can swiftly alter not only physicochemical conditions but also the abundance and composition of the biota. The effect of the diurnal tidal cycle on microbial community composition during different seasons remains uncertain, although this knowledge underlies having effective monitoring programs for water quality and potential identification of health risk conditions. In this study, we assessed the bacterioplankton community composition and diversity across four tidal water levels in a tropical estuary characterized by a mixed semidiurnal tide regime (i.e., two high and two low tides of varying amplitudes) during both dry and wet seasons. The bacterial community composition varied significantly among the four tidal levels, but only during the dry season, when the influence of the seawater intrusion was largest. Bacterial indicators' taxa identified using the Indicator Value Index were found within Cyanobacteria, Actinobacteriota, Bacteroidota, and Proteobacteria. The indicator taxon Cyanobium sp. had a prominent presence across multiple tidal levels. The main predicted phenotypes of the bacterial communities were associated with potential pathogenicity, gram-negative, and biofilm formation traits. While there were no marked predicted phenotypic differences between seasons, pathogenic and gram-negative traits were more prevalent in the dry season, while biofilm formation traits dominated in the wet season. Overall, our findings underscore the intricate relationship between river hydrodynamics and bacterial composition variability and hint a significant human impact on the water quality of the Bangpakong River.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00254-w.