A phytochemical examination of the aerial parts of Hypolepis punctata led to the separation and identification of eight secondary metabolites, comprising a novel pterosin dimer (1) and seven previously identified compounds. The structure of the unique molecule was elucidated using extensive spectroscopic analyses, such as 1D and 2D NMR and high-resolution mass spectrometry. Molecular docking indicated that compound 1 is positioned within the catalytic gorge of acetylcholinesterase, with a calculated binding free energy of-5.23 kcal/mol.

Microalgae-bacteria co-cultures offer a promising strategy to enhance lipid productivity for biofuel production. In this study, 30 symbiotic bacterial strains were isolated from Chlamydomonas reinhardtii cultures, among which Microbacterium paraoxydans, Rhodococcus triatomae, and Stenotrophomonas maltophilia were selected for co-culture with C. reinhardtii cc849. Growth, chlorophyll and lipid contents of C. reinhardtii were detected. The maximal lipid yield of R. triatomae was achieving 63.5% at 90 μmol·m-2·s-1 with 1:50 bacteria-algae ratio on Day 9. M. paraoxydans reached 50.9% lipid content at 60 μmol·m-2·s-1, respectively. Transcriptome sequencing revealed that R. triatomae co-culture upregulated key fatty acid biosynthesis genes (ACC1, fabH, fabF, fabI, fabA) and pyruvate dehydrogenase complex components (especially DLD2, log2FC = 2.26), while downregulating gluconeogenic gene PCK1 (log2FC = −0.75). Accelerated nitrogen and phosphorus depletion was observed in co-cultures, further promoting lipid accumulation. These findings demonstrate that R. triatomae is a highly effective bacterial partner for boosting lipid production in C. reinhardtii and this study provides a basis for algae-bacteria synergistic strategies to improve microalgal biofuel production.

An oleaginous macrofilamentous alga, Vaucheria hamata (No: FACHB-3853), was isolated from Shanghai, China, representing the first systematic characterization of a macrofilamentous alga for lipid production with direct harvestability that may lower lipid production costs. Under natural conditions of 16°C, 10 μE·m-2·s-1, this alga exhibited a lipid content of 30.0% and the maximum biomass 8.06 g·L-1 and lipid content 68.55% of dry weight were achieved in laboratory-scale cultivation with agitation at 160 rpm. Additionally, a total of 5964 differentially expressed genes were identified by transcriptomic analysis and the results revealed that agitation treatment significantly improved lipid yields by upregulated genes involved in fatty acid synthesis, starch metabolism, the tricarboxylic acid cycle, and pentose phosphate pathway. Notably, the total fatty acid content suitable for biodiesel production was 49.45% with 20 mg·L-1 KH2PO4 in the medium, and the levels of polyunsaturated fatty acids (eicosapentaenoic acid and arachidonic acid) used in healthcare products were 13.91% and 2.41%, respectively. This study demonstrated that the macrofilamentous oleaginous alga V. hamata FACHB-3853 was an ideal candidate for both lipid production and nutritional applications, thereby expanding the potential applications of macrofilamentous algae in biotechnology.

A novel species, designated as Stauroneis xuhuiensis sp. nov., has been identified and described from Guilin Park in Shanghai City, China. Utilizing both LM and SEM, detailed observations were conducted to document the size, morphology, and ultrastructural features of this new species. S. xuhuiensis sp. nov. is characterized by linear-lanceolate valves with capitate to subcapitate ends. Its raphe is narrow and linear, while the central area presents a relatively small, rectangular to slightly wedge-shaped stauros. The striae extend radially across the entire valve surface, often displaying irregular spacing. Through comparative analysis with similar Stauroneis species, S. xuhuiensis sp. nov. has been confirmed to exhibit sufficient distinctions in valve size and striae density to warrant recognition as a novel species. This new species inhabits freshwater environments and grows epiphytically on stones. Its discovery contributes to an enhanced understanding of the diversity of freshwater diatoms in China.

Green alga Chlamydomonas reinhardtii possesses efficient photosynthetic capacity and has been considered as a new type of green biodiesel raw material. However, the lipid content of C. reinhardtii was around 20-30%, which is far from meeting the industrial requirements. Screening for oleaginous algal mutants is one of the effective ways to resolve the bottleneck. In this study, a high-lipid-yield C. reinhardtii mutant D5-3 was obtained, achieving maximum lipid yield of 66.06% in nitrogen-depleted TAP medium and 42.2% in TAP medium. The mutation site was located in the intergenic region between genes rbcS1 and rbcS2. This mutation significantly upregulated transcript levels of rbcS1 and rbcS2 and increased Rubisco enzyme activity compared with the control. Furthermore, transcriptome analysis was performed to reveal the mechanism of the high lipid production in D5-3. The transcriptomic data revealed global metabolic reprogramming under optimal lipid production conditions, characterized by coordinated upregulation of genes involved in photosynthesis and Calvin cycle, glycolysis, pentose phosphate pathway, fatty acid synthase and TAG assembly. The total content of biodiesel-relevant fatty acids (primarily C16:0, C18:1, C18:2, and C18:3) reached 12-13% of dry weight, accounting for 90–92% of the total FAME profile. This study established mutant D5-3 as a promising strain for biodiesel production and provided mechanistic insights into the regulatory network linking Rubisco activation with enhanced lipid biosynthesis in microalgae.

Four new species of monoraphid diatoms belonging to the genus Planothidium were studied and described from the karst region of Guizhou Province, China. The morphological characteristics of these new species were observed and documented using light and scanning electron microscopy. Planothidiumpseudoreichardtii sp. nov. exhibits a broad sinus at the central area on the interior of the rapheless valve, linear shallow depressions and a unique enlarged areola at the end of the striae on the exterior rapheless valve. Planothidiumliboensis sp. nov. is characterized by 4-5 rows striae on both valves, a cavum at the central area on the interior rapheless valve and irregular depressions on the exterior rapheless valve. Planothidiumangustirostratum sp. nov. features elliptical valves with narrowly rostrate apices, a cavum at the central area of interior rapheless valve and circular depressions on the exterior rapheless valve. Planothidiummaolanensis sp. nov. has elliptical valves without protracted apices, coarsely-spaced striae on the one side of the central area of the both valves. These four new species were compared with other similar Planothidium taxa. In addition, ecological information was provided and the stability of some features was discussed.

A new species, Caloneis nanyiensis sp. nov., is described from Nanyi Lake, the largest lake in southern Anhui Province, China. Observations were made using a light and scanning electron microscope documenting the size, shape and ultrastructure of the new species. Caloneis nanyiensis sp. nov. has rhombic valves with acutely rounded apices. The raphe is narrow and arched. An internal axial plate covers the alveoli, leaving small marginal openings bordered by costa, thickened and raised from the valve face. The striae are slightly radiate to parallel in the central area, becoming radiate towards the apices. By comparing the new species with similar Caloneis species, C. nanyiensis sp. nov. was confirmed to be sufficiently different with respect to valve size and striae density to be recognised as new to science. The new species lives in freshwater habitats and epiphytic on Cladophora. The discovery enhances our knowledge of the diversity of freshwater diatoms in China.

Euglena sanguinea (Ehrenberg 1831) is one of the earliest reported species within the genus Euglena. Its prolific proliferation leading to red algal bloom has garnered significant scientific attention due to its ecological and environmental impacts. Despite this, research on E. sanguinea remains relatively sparse. In this study, we isolated and purified algal strains collected from the water of the Shanghai Botanical Garden, identifying them as E. sanguinea based on 16S and 23S rDNA sequence alignment. The cellular density and carotenoids content of E. sanguinea were observed to vary under different abiotic culture conditions, including varying temperatures, light intensities, potassium iodide and sucrose concentration. Notably, significant rapid accumulation of carotenoids in E. sanguinea was observed under continuous culture at a light intensity of 130 µmol m− 2 s − 1. Furthermore, exposure to a strong light intensity resulted in changes in the activity of the antioxidant enzymes and malondialdehyde (MDA) content. Moreover, through de novo transcriptome sequencing and Gene Ontology (GO) analysis of E. sanguinea cultured under different light intensities, we identified a total of 111 differentially expressed genes (DEGs), comprising 44 upregulated and 67 downregulated genes. Among these, eight genes are associated with photosynthesis and chloroplast function, including upregulated genes encoding Photosystem II protein D1, Photosystem II protein K, and Cytochrome b6/f complex subunit V, as well as translation elongation factor EF-Tu; conversely, downregulated genes include those encoding cell wall-associated hydrolases and enzymes involved in carbon fixation in photosynthetic organisms. These findings provide foundational data for investigating the photoprotective mechanisms in E. sanguinea and serve as a reference for the regulatory factors involved in carotenoids biosynthesis within Euglena.

Eight species of the genus Gogorevia (Bacillariophyta) are reported from across China, of which five have been previously described and three of them, namely Gogorevia ellipticum sp. nov., Gogorevia rectangularis sp. nov., and Gogorevia subconstricta sp. nov., are new to science. The three new species are descripted in morphology with light and scanning electron microscope and compared with other closely related species of Gogorevia. Specifically, G. ellipticum sp. nov. has an elliptical valve with subrostrate or capitate apices. G. rectangularis sp. nov. has an elongated and rectangular valve with rostrate apices, parallel and slightly constricted at the center margins. G. subconstricta sp. nov. has a linear-elliptical valve with clearly undulate margins that are constricted in the center, protracted and distinctly capitate apices. This study enriched our knowledge on the species diversity and geographical distribution of Gogorevia in the world.

A novel monoraphid diatom species, Cocconeis crisscrossis You, Yu, Kociolek & Wang, sp. nov. is examined and described from the Qingyi River and Maolan Nature Reserve of southern China. The morphological description is based on light microscopy and scanning electron microscopy observations and the new species is compared with similar taxa in this genus. The characteristics unique to Cocconeis crisscrossissp. nov. include its central area extending irregularly to both sides, it having closed valvocopulae with heavily silicified fimbriate margins and poles of the valvocopulae have ‘sword-shaped’ siliceous extensions. These features differentiate this new species from others in the genus. This new species was found in alkaline waterbodies, including streams, waterfall and ponds. It was usually found as an epiphyte on the stones; however, it was present on other substrates such as mosses.

Two new freshwater centric diatom species were described from the southwest of China based on light and scanning electron microscopy. Pliocaenicus weixiense sp. nov. has a transversely undulate valve face, marginal fultoportulae situated at the end of the hyaline strips, central fultoportulae forming a ring positioned in a circular pattern, each with 3–4 (usually 3) satellite pores, and a single rimoportula located at the base of the inner distal end of the costa. Tertiarius aspera sp. nov. has an uneven valve face with small granules that may be present on the marginal area and valve mantle, marginal fultoportulae situated on each costa close to the margin of the valve, 6–7 central fultoportulae forming a ring near the valve center each with two satellite pores, and one rimoportula located on the valve face/mantle junction in the middle of costa on the internal valve. T. aspera sp. nov. is the first reported extant species in the genus. This study played an important role in studying the taxonomic status and ecological information of the genus, and the establishment of the two new taxa will help demonstrate the unique nature of freshwater diatom flora in the southwest of China.

[ Objective ] In order to enrich the diversity of periphytic diatoms in the Yangtze River Basin , systematic sampling was carried out in this study. [ Methods ] The microstructure and ultrastructure of the diatom samples were observed by light microscope and scanning electron microscope. [ Results ] A newly recorded species of diatom from China , Livingstonia palatkaensis Prasad & Nienow , was found from Jin􀆴e Mountain in Yueyang City , Hunan Province. This genus was also the first to be discovered in China. [ Conclusion ] The discovery of this newly recorded species provided new information on the geographical distribution of this genus.

Zooplankton, particularly the rotifera group, plays a crucial role in aquatic ecological monitoring. Nevertheless, some challenges arose as applying rotifers as indicators. In this study, which focused on the waters of and surrounding Shanghai. The effectiveness of three rotifer indices( QB/T, E/ O and TSIROT) were evaluated for assessing the nutritional status of water. The relationships between rotifer density, biomass and diversity indices with the nutritional status of aquatic environments were discussed. The results were as follows. The TSIROT index and rotifer biomass were somewhat reliable in indicating the nutritional status of water, but the evaluation effectiveness was significantly influenced by seasonal variations. In Shanghai, the TSIROT index was more suitable in summer and autumn, but not in winter and spring. During summer, rotifer density and biomass correlated most closely with TLI. As TLI increases, rotifer density proved to be a more effective indicator than their biomass. In regions characterized by distinct seasons and predominantly eutrophic water bodies, assessing the nutritional status of water using either the QB/T index or the E/ O index was inappropriate, as both methods had limitations in such environments. In Shanghai, using α diversity indices(Shannon, Simpson, Pielou) to assess water nutrition levels was unsuitable, as these indices showed minimal variance in concentration ranges across different nutritional stages of water bodies. Additionally, during the summer, habitat emerged as one of the key factors influencing the accuracy of rotifers in indicating the nutritional status of water bodies. Furthermore, the consistency of the evaluation results between TSIROTP and TSIROTD, as well as between TSIROTP and TSIROTZH, was relatively low. Therefore, a thorough understanding of the hydrological state of the assessed lakes was necessary before applying the TSIROT index to ensure its precision.

Diatom cell walls are diverse and unique, providing the basis for species identification and supporting the ecological and economic value of diatoms. However, these important structures sometimes change in response to environmental fluctuations, especially under salt adaptation. Although studies have shown that salinity induces morphological plasticity changes in diatom cell walls, most research has focused on physiological responses rather than molecular mechanisms. In this study, Skeletonema subsalsum was cultured under four salinity conditions (0, 3, 6, 12). Through morphological and physiological methods, we found that salinity increased the cell diameter, protrusion lengths, distance between adjacent cells (DBCs), and nanopore size, while reducing cell height and silicification degree. To further investigate the mechanism underlying morphological changes in S. subsalsum, complementary transcriptome analysis was performed. In total, 20,138 differentially expressed genes (DEGs) were identified among the four treatments. Among them, 231 DEGs were screened and found to be closely associated with morphological changes, of which 107 were downregulated and 124 were upregulated. The findings demonstrated that elevated salinity inhibited silicon transport and deposition via downregulating the expression of DEGs involved in functions including chitin metabolism, putrescine metabolism, and vesicle transport, resulting in reduced silicon content and cell height. Increased salinity promoted the expression of DEGs related to microtubules (MTs), actin, and ubiquitin, which synchronously induced morphological changes. These findings provide a more comprehensive understanding of the salt tolerance of algae and a foundation for future studies on cell wall morphogenesis.

In our recent investigations of diatom diversity, we studied three species, namely, Skeletonema costatum , Skeletonema subsalsum , and Skeletonema potamos . Although they have been found frequently in Changjiang (Yangtze) River Basin, their morphological and molecular identification is difficult in taxonomy. Therefore, to integrate morphological and molecular biological approaches, we compared systematically their morphological characters and performed phylogenetic analysis. Twelve strains of Skeletonema were collected and isolated from Shanghai and Jiangsu, China, and their morphological characteristics were examined by light microscopy (LM) and the scanning electron microscopy (SEM). Based on morphological comparison, we determined that S. potamos is easy to distinguish from the other two species. The heavily silicified areolae, undulated or cleft distal ends of terminal fultoportula processes (TFPPs), absence of basal pores of fultoportula processes (FPPs), the root-like protrusions of FPPs, and no interlocking connection are the stable characteristics that can be used to identify S. potamos . However, there are only two features that can distinguish S. costatum from S. subsalsum , namely the location of terminal rimoportulae (TRPs) and the distal shape of TFPPs. In addition, we amplified and sequenced nine common genetic markers from the strains, from which 101 sequences were obtained, constructed phylogenetic trees based on the nine genes and evaluated that seven genes can be used to identify S. potamos , and revealed that S. subsalsum is the closest known relative of S. costatum , and only ATP synthetase beta-subunit gene ( atp B) is able to distinguish them from each other, which strongly support that it is an effective molecular marker for Skeletonema . This work provided a theoretical basis for the taxonomic study of Skeletonema.

The process of the tapetal apoptosis is a key event in microsporogenesis.Previous studies have mainly focused on angiosperms,but ferns have not reported this aspect.The cytological features of the ta-petal cells during apoptosis of Osmunda japonica was studied using transmission electron microscopy(TEM)and immunofluorescence technology.The main aim of this paper is to clarify the development type and apoptosis characteristics of tapetal cells of O.japonica.It provides a basis for the further study of ta-petum cell apoptosis and spore development of ferns.The results showed that:(1)the structure of tape-tum in Osmunda was of the mixed type.The outer layer of the tapetum was of the secretion type,and the inner layer of the tapetum was of plasmodium type.(2)The plasmodium tapetum underwent apoptosis during development.The cell wall and plasmalemma degenerated and the cytoplasm became dense and gradually vacuolated.The nuclei were collapsed and deformed.The chromatin condenses and small nucleo-li were formed.The DAPI fluorescence staining became weak gradually.Organelles of mitochondria,plas-tids,endoplasmic reticulum,Golgi bodies gradually degenerated.The vacuoles contained fibrous,floccu-lent,dark osmiophilic granules and some small vesicles.Multi-vesicle bodies and multi-membrane bodies and apoptosis bodies occurred in the tapetal cells.(3)In contrast to seed plant,apoptosis of Osmunda started earlier than in seed plants;no nucleus apoptosis bodies occured during apoptosis.Besides sporopol-lenin,the tapetal cells also produced the fibrous,flocculent,dark osmiophilic granules during apoptosis.The materials were considered to form perispore of ferns.

In order to promote the improvement of the rural living environment, the treatment of rural domestic sewage has attracted much attention in China. Meanwhile, the rural regions’ sewage discharge standards are becoming increasingly stringent. However, the standard compliance rate of total phosphorus (TP) is very low, and TP has become the main limiting pollutant for the water pollutants discharge standards of rural domestic sewage treatment facilities. In this study, waste eggshell (E) was employed as a calcium source, and waste peanut shell (C) was employed as a carbon source to prepare calcium-modified biochar adsorbent materials (E-C). The resulting E-C adsorbent materials demonstrated efficient phosphate (P) adsorption from aqueous solutions over the initial pH range of 6–9 and had adsorption selectivity. At an eggshell and peanut shell mass ratio of 1:1 and a pyrolysis temperature of 800 °C, the experimental maximum adsorption capacity was 191.1 mg/g. The pseudo second-order model and Langmuir model were best at describing the adsorption process. The dominant sorption mechanism for P is that Ca(OH)2 is loaded on biochar with P to form Ca5(PO4)3OH precipitate. E-C was found to be very effective for the treatment of rural domestic sewage. The removal rate of TP in rural domestic sewage was 91–95.9%. After adsorption treatment, the discharge of TP in rural sewage met the second-grade (TP < 3 mg/L) and even first-grade (TP < 2 mg/L). This study provides an experimental basis for efficient P removal by E-C adsorbent materials and suggests possible applications in rural domestic sewage.

Twenty compounds were isolated from the fern of Pyrrosia davidii (Baker) Ching. These compounds included three steroids (1, 2, and 3), one pigment (4), eleven flavonoids (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15), two terpenoids (16, 17), one phenolic acid (18), and two fatty acids (19, 20). The structures of the compounds were determined by comparison of measured NMR spectroscopic data with previously reported data. Except for Compound 1 and 11, all the compounds were isolated for the first time from Pyrrosia davidii (Baker) Ching, and Compounds 6, 9, 17, 19, and 20 were isolated for the first time from the genus Pyrrosia Mirbel. The chemotaxonomic significance of these compounds was discussed.