Later Stages Of Culture Research Articles

Inhibitory Effect of Combined Exposure to Copper Ions and Polystyrene Microplastics on the Growth of Skeletonema costatum

As two significant pollutants, the increased concentrations of copper ions and microplastics in coastal waters pose a substantial threat to the health of marine ecosystems. This study explored the individual and combined toxic effects of copper ions and microplastics on the marine diatom Skeletonema costatum. The results indicated that copper ions at a concentration of 0.05 mg/L exerted a negative impact on the growth of S. costatum; however, the influence of microplastics on algal cell growth was more complex: there was no significant inhibition of algal cell growth observed within the first 72 h of cultivation, but a pronounced negative effect on cell growth was noted between 72 and 96 h, with high concentrations (10.00 mg/L) of microplastics even causing a premature stagnation phase in algal cell growth. When both pollutants were present simultaneously, their impact on cell growth was similar to that of the microplastic pollution group, yet the growth condition was better than that of the copper ion pollution group. Through investigation of adsorption rates and toxicity mitigation rates, it was found that the adsorption of copper ions by microplastics was a significant reason for the improved growth condition of algal cells in the mixed pollution group compared to the copper ion pollution group. However, in the later stages of cultivation, the inhibitory effect of microspheres on algal cell growth counteracted their mitigating effect on copper ion toxicity. This study provides a reference for evaluating the impact of microplastics and heavy metals on coastal ecosystem health and for revealing the interactions between different pollutants.

Improving microalgal growth and nitrogen, and phosphorus removal by electric field in municipal wastewater

The promoting effect of electric fields on the growth and lipid production of microalga provides a new research direction for biorefining. However, researchers have rarely applied this technology to the treatment of actual wastewater. In this study, the dry weight and lipid content of microalgae increased by 47.45 % and 28.28 %, respectively, when optimized for light, growth phase and energization time. By optimizing the initial microalgal concentration and the ratio of nitrogen and phosphorus, the removal of total nitrogen (TN) and ammonia nitrogen (NH4+) increased by 18.5 % and 10.9 %, respectively. Compared to peroxidase (POD), significant changes in the relative activities of catalase (CAT) and total superoxide dismutase (T-SOD) were observed after the application of an electric field to the microalgae. Along with the cultivation, the relative activities of T-SOD and CAT showed a tendency of an increase and then a decrease compared with the control. This was mainly due to the increased internal secretion of T-SOD and CAT by the microalgae in response to the oxidative stress of the electric field on the microalgae, while the lack of nutrients at the later stages of cultivation also led to the increase of the content of the two enzymes in the control.

Influences of the Integrated Rice-Crayfish Farming System with Different Stocking Densities on the Paddy Soil Microbiomes.

Integrated rice-fish farming has emerged as a novel agricultural production pattern to address global food security challenges. Aiming to determine the optimal, scientifically sound, and sustainable stocking density of red claw crayfish (Cherax quadricarinatus) in an integrated rice-crayfish farming system, we employed Illumina high-throughput 16S rRNA gene sequencing to evaluate the impact of different stocking densities of red claw crayfish on the composition, diversity, function, and co-occurrence network patterns of soil bacterial communities. The high stocking density of red claw crayfish reduced the diversity and evenness of the soil bacterial community during the mid-culture stage. Proteobacteria, Actinobacteria, and Chloroflexi emerged as the most prevalent phyla throughout the experimental period. Low stocking densities initially boosted the relative abundance of Actinobacteria in the paddy soil, while high densities did so during the middle and final stages. There were 90 distinct functional groups identified across all the paddy soil samples, with chemoheterotrophy and aerobic chemoheterotrophy being the most abundant. Low stocking densities initially favored these functional groups, whereas high densities enhanced their relative abundances in the later stages of cultivation. Medium stocking density of red claw crayfish led to a more complex bacterial community during the mid- and final culture stages. The experimental period showed significant correlations with soil bacterial communities, with total nitrogen (TN) and total phosphorus (TP) concentrations emerging as primary factors contributing to the alterations in soil bacterial communities. In summary, our findings demonstrated that integrated rice-crayfish farming significantly impacted the soil microbiomes and environmental factors at varying stocking densities. Our study contributed to theoretical insights into the profound impact of integrated rice-crayfish farming with various stocking densities on bacterial communities in paddy soils.

Obtaining Gene-Modified HLA-E-Expressing Feeder Cells for Stimulation of Natural Killer Cells.

Human cytomegalovirus (HCMV)-specific adaptive NK cells are capable of recognizing viral peptides presented by HLA-E on infected cells via the NKG2C receptor. Using retroviral transduction, we have generated a K562-cell-based line expressing HLA-E in the presence of the HLA-E-stabilizing peptide, which has previously shown the capacity to enhance adaptive NK cell response. The obtained K562-21E cell line was employed to investigate proliferative responses of the CD57- NK cell subset of HCMV-seropositive and seronegative donors. Stimulation of CD57- NK cells with K562-21E/peptide resulted in an increased cell expansion during the 12-day culturing period, regardless of the serological HCMV status of the donor. The enhanced proliferation in response to the peptide was associated with a greater proportion of CD56brightHLA-DR+ NK cells. In later stages of cultivation, the greatest proliferative response to K562-21E/peptide was shown for a highly HCMV-seropositive donor. These expanded NK cells were characterized by the accumulation of CD57-KIR2DL2/3+NKG2C+NKG2A- cells, which are hypothesized to represent adaptive NK cell progenitors. The K562-21E feeder cells can be applied both for the accumulation of NK cells as therapeutic effectors, and for the study of NK cell maturation into the adaptive state after the HLA-E peptide presentation.

Overexpression of the Transcription Factor Azf1 Reveals Novel Regulatory Functions and Impacts β-Glucosidase Production in Trichoderma reesei.

The fungus Trichoderma reesei is an essential producer of enzymes that degrade lignocellulosic biomass to produce value-added bioproducts. The cellulolytic system of T. reesei is controlled by several transcription factors (TFs) that efficiently regulate the production of these enzymes. Recently, a new TF named Azf1 was identified as a positive regulator of cellulase expression. Here, we investigated novel regulatory functions of Azf1 by its overexpression. In the mutant strain OEazf1, overexpression of azf1 was achieved under both repression and induction conditions. Although azf1 was more abundant in transcript and protein, overexpression of this TF did not activate transcription of the cellulase gene in the presence of the repressor glucose, suggesting that Azf1 may be subject to posttranslational regulation. In cellulose, the expression of swo, encoding the accessory protein swollenin, and the β-glucosidases cel1a, cel1b, cel3b, and cel3g increases in the early stages of cultivation. The increased production of these β-glucosidases increases the hydrolysis rate of cellobiose and sophorose, which activates carbon catabolite repression (CCR) and causes repression of cellulase genes and the regulator Xyr1 in the later stages of cultivation. Moreover, overexpression of azf1 led to increased cellulase activity in T. reesei during long-term cultivation in cellulose and sugarcane bagasse. Our results provide new insights into the mechanisms regulating Azf1 and novel genes that are important targets of this TF. This work contributes to a better understanding of the complex mechanisms regulating cellulase expression in T. reesei. It will contribute to the development of strains with higher production of these essential enzymes.

Effects of emodin and different protein levels on growth and immunity of the blunt snout bream (Megalobrama amblycephala) for in-pond raceway aquaculture systems

The present study aimed to evaluate the effects of emodin and different protein levels on growth-promoting antioxidant capacity and protein utilization of blunt snout bream to in-pond raceway aquaculture systems (IPRS). The experiment was divided into three groups: low protein group (LP) (29% low protein level), high protein group (HP) (32% high protein level), and emodin group (ED) (29% protein level + 0.05% emodin). At 210 days in the late stage of culture, the weight of the ED and HP groups was higher than the LP groups (P < 0.05). Compared with the LP group, the number of hematological parameters (white blood cell, WBC; red blood cell, RBC; hemoglobin, HGB; and hematocrit, HCT), blood antioxidant enzymes (anti-superoxide anion free radical, ASAFA; glutathione peroxidase, GPx; superoxide dismutase, SOD; and nitric oxide, NO) activity in the ED group were significantly increased (P < 0.05), and the serum malondialdehyde (MDA) content were significantly reduced (P < 0.05). Besides, the content of serum triglyceride (TG) and blood antioxidant enzymes (ASAFA, GPx, and SOD) in the HP group were significantly increased compared with the LP group (P < 0.05), and the content of serum Creatinine (CREA) significantly lower than that of the control (P < 0.05). The results of this experiment indicate that emodin and appropriate protein levels can increase the content of antioxidant enzymes, enhance immunity, and promote the growth of M. amblycephala.

Disentangling the growth curve of microbial culture

Many researchers have studied the population dynamics of microbe of microbes as a typical example of population dynamics. The Monod equation, which mainly focuses on the growth and stationary phases, is used when plotting a growth curve. However, the growth potential in the late stage of culture has been overlooked. Previous studies considered the direct degradation of products to the limiting substrate. In this study, we considered microbial growth during the stationary phase, which enables us to describe the dynamics precisely. The microbes were divided into two populations: one grew by consuming the limiting substrate and the other degraded the products by metabolism. According to the numerical analysis of our model, microbes may choose one of two strategies: one consumes substrates and expands quickly, and the other grows slowly while cleaning up the environment in which they thrive. Furthermore, we found three types of microbial growth depending on their ability to detect metabolite accumulation. Using experimentally measured data, this model can estimate the dynamics of cell density, the substrates, and the metabolites used. The model’s disentangling of growth curves offers novel interpretive possibilities for culture system dynamics.

The Marine Factor 3,5-Dihydroxy-4-methoxybenzyl Alcohol Represses Adipogenesis in Mouse 3T3-L1 Adipocytes In Vitro: Regulating Diverse Signaling Pathways

The augmentation of adipocytes in the adipose tissues brings disordered pathophysiological conditions, including type 2 diabetes, hyperlipidemia, hypertension, cardiovascular disease, and cancer. The phenolic antioxidant 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA) prevents oxidative stress as radical scavenging in cells. However, the role of the disorder as a pharmacologic factor has been poorly understood. This study elucidates the regulatory effects of DHMBA on adipogenesis in mouse 3T3-L1 adipocytes in vitro. The 3T3-L1 preadipocytes were cultured in DMEM containing 10% calf fetal serum in the presence of DHMBA. Culturing with DHMBA repressed the growth of 3T3-L1 preadipocytes cultured in a medium without differentiation factors. Interestingly, when 3T3-L1 preadipocytes were cultured in a medium including differentiation factors containing insulin, DHMBA did not affect the number of cells with the differentiation process of adipogenesis. Culturing with DHMBA (1, 10, or 100 μM) inhibited lipid accumulation in adipocytes and repressed adipogenesis in 3T3-L1 cells. The potent inhibitory effects of DHMBA on adipogenesis were seen at the later stage of culture. Adipogenesis was inhibited by the presence of wortmannin, PD98059, or Bay 11-7082, which are inhibitors of pathways related to insulin signaling pathway. Notably, the suppressive effects of DHMBA on adipogenesis were expressed by the presence of these inhibitors. DHMBA treatment declined the levels of PPARy and C/EBPα related to preadipocyte differentiation and PI3 kinase 100α, Akt, MAPK, phosphor-MAPK, and mTOR implicated in the insulin signaling pathway, leading to adipogenesis promotion. Thus, DHMBA may inhibit adipogenesis via regulating diverse signaling pathways, providing a new strategy for the therapy of obesity.

A novel type of serum‑free medium for culturing human airway epithelium cells.

The present study aimed to evaluate the ability of a novel serum-free medium (SFM) to culture human airway epithelium cells (hAECs). hAECs were cultured in the novel SFM as the experimental group in the PneumaCult-Ex medium and Dulbecco's modified eagle medium (DMEM) and fetal bovine serum (FBS) as the control groups. Cell morphology, proliferative capacity, differentiation capacity and expression levels of basal cell markers were assessed accordingly in both culture systems. Optical microscope photos of hAECs were collected for cell morphology assessment. Cell Counting Kit-8 assay was conducted to assess the proliferation ability, and an air-liquid interface (ALI) assay was conducted to assess the differentiation capacity. Markers for proliferating basal and differentiated cells were relatively identified by immunohistochemical and immunofluorescent analysis. The results show that whether grown in the novel SFM or Ex medium, hAECs exhibited similar morphology at every passage, whereas cells could hardly form colonies in the DMEM + FBS group. Cells typically exhibited cobblestone shape, while a proportion of them in the novel SFM at late passage exhibited a larger shape. White vesicles appeared in the cytoplasm of some control cells at the later stage of culture. Basal cell markers (P63+KRT5+KI67+CC10-) for proliferating ability were found in the hAECs cultured by the novel SFM and Ex medium. hAECs at passage 3 cultured in the novel SFM and Ex medium both had the capacity to differentiate into ciliated cells (acetylated tubulin+), goblet cells (MUC5AC+) and club cells (CC10+) in the ALI culture assay. In conclusion, the novel SFM was capable of culturing hAECs. The hAECs cultured by the novel SFM could proliferate and differentiate in vitro. The novel SFM does not change the morphological characteristics or biomarkers of hAECs. The novel SFM has the potential for the amplification of hAECs for scientific research and clinical application.

Цитогенетический анализ клеточной линии мультипотентных мезенхимальных стромальных клеток человека при длительном культивировании после воздействия рентгеновского излучения в малых и средних дозах

Purpose: To evaluate the frequency and spectrum of chromosome aberrations under X-Ray exposure at doses of 80, 250, and 1000 mGy in a human multipotent mesenchymal stromal cell (MMSC) cell line during long-term cultivation. Material and methods: MMSCs were isolated from human gingival mucosa by an enzymatic method and cultured in a serum-free medium. The presence of surface antigens was determined using the method of flow cytometry. The ability of the cell line to differentiate in the osteogenic, adipogenic, and chondrogenic directions was studied using induction media. Authentication was performed by genotyping of polymorphic STR loci, cytogenetic analysis was performed by multicolor fluorescent in situ hybridization (mFISH). Irradiation was carried out on an X-ray biological unit RUB RUST-M1 (Russia) at a dose rate of 40 mGy/min, a voltage of 100 kV, and a current of 0.8 mA. Results: At the first passage after irradiation, a statistically significant increase in the frequency of non-clonal CA compared with the control was recorded at a dose of 80, but not 250 and 1000 mGy. At the late stages of cultivation, the average frequency of breaks per chromosome in the group of non-irradiated cells did not differ from the values obtained after irradiation at doses of 80, 250, and 1000 mGy (p > 0.05). However, in MMSCs irradiated at a dose of 80 mGy, damage occurred more often in pairs of chromosomes 6 and 10, and at a dose of 1000 mGy, in a pair of chromosomes 9. A single irradiation of MMSCs in vitro did not affect the growth and progression of MMSCs characteristic of the studied primary cell line, of clonal cells with chromosome translocations and monosomy X, but led to an increase in the representation of a clone with tetrasomy 8. The total number of random clones with chromosome translocations that arose de novo increased after irradiation at a dose of 1000 mGy. Conclusion: Minor fluctuations in the proportion of cells with non-clonal CA, depending on the dose received in the early stages after irradiation (passage 1–4), disappeared at the later stages of cultivation (passage 8–14). There were no differences in mean frequencies between irradiated and non-irradiated MMSCs, but after irradiation, damage to some chromosomes could occur more frequently than others. A single X-ray irradiation of MMSCs can promote the growth and progression of primary pathological cytogenetic clones, regardless of the dose received, as well as an increase in the total number of de novo cell clones with chromosomal translocations that have arisen. A single X-ray irradiation of MMSCs can promote the growth and progression of primary pathological cytogenetic clones, regardless of the dose received, as well as an increase in the total number of de novo cell clones with chromosomal translocations that have arisen.

Uncovering Gene Expression Profiles of Three Morphologic Mycelium Forms of the Chinese Caterpillar Mushroom Ophiocordyceps sinensis (Ascomycota) Using High-Throughput Sequencing

The asexual form of Ophiocordyceps sinensis has been controversial, but various morphologic mycelium appeared when O. sinensis was cultured under experimental conditions. To explore the generation mechanism of morphologic mycelium, developmental transcriptomes were analyzed from three kinds of mycelium (aerial mycelium, hyphae knot, and substrate mycelium). The results showed that diameter and morphology of these three kinds of mycelium were obviously different. KEGG functional enrichment analysis showed that the differential expressed genes (DEGs) of substrate mycelium were enriched in ribosomes and peroxisomes, indicating that prophase culture was rich in nutrients and the metabolism of substrate mycelium cells was vigorous in the stage of nutrient absorption. The up-DEGs of hyphae knot were mainly enriched in the oxidative phosphorylation pathway, indicating that oxidative phosphorylation was the main energy source for mycelium formation in the stage of nutrient accumulation and reproductive transformation. The up-DEGs of aerial mycelium were mainly enriched in the synthesis and degradation pathways of valine, leucine, and isoleucine, suggesting that the occurrence of aerial mycelium was related to amino acid metabolism at the later stage of culture, and nutritional stress accelerated the reproduction of asexual spores. In addition, the important roles of mycelium formation related genes were verified by combined analysis of qRT-PCR and transcriptome sequencing. Collectively, this study will provide theoretical guidance for inhibiting the occurrence of aerogenous mycelium and promoting the development of mycelium into pinhead primordia in the culture of O. sinensis in the future.

Revisiting the involvement of tau in complex neural network remodeling: analysis of the extracellular neuronal activity in organotypic brain slice co-cultures

Objective. Tau ablation has a protective effect in epilepsy due to inhibition of the hyperexcitability/hypersynchrony. Protection may also occur in transgenic models of Alzheimer’s disease by reducing the epileptic activity and normalizing the excitation/inhibition imbalance. However, it is difficult to determine the exact functions of tau, because tau knockout (tauKO ) brain networks exhibit elusive phenotypes. In this study, we aimed to further explore the physiological role of tau using brain network remodeling. Approach. The effect of tau ablation was investigated in hippocampal-entorhinal slice co-cultures during network remodeling. We recorded the spontaneous extracellular neuronal activity over 2 weeks in single-slice cultures and co-cultures from control and tauKO mice. We compared the burst activity and applied concepts and analytical tools intended for the analysis of the network synchrony and connectivity. Main results. Comparison of the control and tauKO co-cultures revealed that tau ablation had an anti-synchrony effect on the hippocampal-entorhinal two-slice networks at late stages of culture, in line with the literature. Differences were also found between the single-slice and co-culture conditions, which indicated that tau ablation had differential effects at the sub-network scale. For instance, tau ablation was found to have an anti-synchrony effect on the co-cultured hippocampal slices throughout the culture, possibly due to a reduction in the excitation/inhibition ratio. Conversely, tau ablation led to increased synchrony in the entorhinal slices at early stages of the co-culture, possibly due to homogenization of the connectivity distribution. Significance. The new methodology presented here proved useful for investigating the role of tau in the remodeling of complex brain-derived neural networks. The results confirm previous findings and hypotheses concerning the effects of tau ablation on neural networks. Moreover, the results suggest, for the first time, that tau has multifaceted roles that vary in different brain sub-networks.

Kinetic-model-based pathway optimization with application to reverse glycolysis in mammalian cells.

Over the last two decades, model-based metabolic pathway optimization tools have been developed for the design of microorganisms to produce desired metabolites. However, few have considered more complex cellular systems such as mammalian cells, which requires the use of nonlinear kinetic models to capture the effects of concentration changes and cross-regulatory interactions. In this study, we develop a new two-stage pathway optimization framework based on kinetic models that incorporate detailed kinetics and regulation information. In Stage 1, a set of optimization problems are solved to identify and rank the enzymes that contribute the most to achieving the metabolic objective. Stage 2 then determines the optimal enzyme interventions for specified desired numbers of enzyme adjustments. It also incorporates multi-scenario optimization, which allows the simultaneous consideration of multiple physiological conditions. We apply the proposed framework to find enzyme adjustments that enable a reverse glucose flow in cultured mammalian cells, thereby eliminating the need for glucose feed in the late culture stage and enhancing process robustness. The computational results demonstrate the efficacy of the proposed approach; it not only captures the important regulations and key enzymes for reverse glycolysis but also identifies differences and commonalities in the metabolic requirements for different carbon sources.

Ultraviolet radiation promotes the production of hispidin polyphenols by medicinal mushroom Inonotus obliquus

Production of hispidin polyphenols in Inonotus obliquus is a stress-induced response triggered by environmental factors. As one of the important environmental factors, ultraviolet (UV) radiation plays regulatory roles in fungal growth and development. However, whether UV radiation regulates the formation of hispidin polyphenols remains to be established. In this study, we cultivated I. obliquus on solid medium and imposed intermittent UV radiation. We showed that UV exposure inhibited the growth of mycelia but increased the production of polyphenols. Further bioassays revealed that UV radiation also increased the catalytic activities of phenylalanine ammonia-lyase (PAL) and chalcone isomerase (CHI), up-regulated expression of genes related to redox, transcriptional regulation, and metabolism. In addition, the total extracts from the UV-irradiated group were more capable of scavenging DPPH and ABTS+ free radicals, especially at the later stage of culture. Thus, UV radiation, acting as one of the environmental factors, stimulated the accumulation of polyphenols in I. obliquus by regulating the activities of enzymes and the expression of genes related to growth and metabolism, and can be tentatively used as a feasible strategy to enhance the production of polyphenols in I. obliquus.

Acetate accumulation and regulation by process parameters control in Chinese hamster ovary cell culture.

Chinese hamster ovary (CHO) cells represent a group of predominantly used mammalian hosts for producing recombinant therapeutic proteins. Known for theirrapid proliferation rates, CHO cells undergo aerobic glycolysis that is characterized by fast glucose consumption, that ultimately gives rise to a group of small-molecule organic acids. However, only the function of lactate has been extensively studied in CHO cell culture. In this study, we observed the accumulation of acetate from the late exponential phase to harvest day, potentially contributing to the pH decline in late culture stage regardless of lactate consumption. In addition, we evaluated the acidification of the fresh media and the cell culture suspension, and the data revealed that acetate presented a lower acidification capacity compared to lactate and exhibited limited inhibitory effect on cells with less than 20 mM supplemented in the media. This study also explored the ways to control acetate accumulation in CHO cell culture by manipulating the process parameters such as temperature, glucose, and pH control. The positive correlation between the specific glucose consumption rate and acetate generation rate provides evidence of the endogenous acetate generation from overflow metabolism. Reducing these parameters (temperature, glucose consumption) and HCl-controlled low pH ultimately suppress acetate build-up. In addition, the specific acetate generation rate and relevant glucose consumption rate are found to be a metabolic trait associated with specific cell lines. Taken together, the results presented in these experiments provide a means to advance industrial CHO cell culture process control and development.

Recognition of terminal buds of densely-planted Chinese fir seedlings using improved YOLOv5 by integrating attention mechanism.

Accurate and timely information on the number of densely-planted Chinese fir seedlings is essential for their scientific cultivation and intelligent management. However, in the later stage of cultivation, the overlapping of lateral branches among individuals is too severe to identify the entire individual in the UAV image. At the same time, in the high-density planting nursery, the terminal bud of each seedling has a distinctive characteristic of growing upward, which can be used as an identification feature. Still, due to the small size and dense distribution of the terminal buds, the existing recognition algorithm will have a significant error. Therefore, in this study, we proposed a model based on the improved network structure of the latest YOLOv5 algorithm for identifying the terminal bud of Chinese fir seedlings. Firstly, the micro-scale prediction head was added to the original prediction head to enhance the model’s ability to perceive small-sized terminal buds. Secondly, a multi-attention mechanism module composed of Convolutional Block Attention Module (CBAM) and Efficient Channel Attention (ECA) was integrated into the neck of the network to enhance further the model’s ability to focus on key target objects in complex backgrounds. Finally, the methods including data augmentation, Test Time Augmentation (TTA) and Weighted Boxes Fusion (WBF) were used to improve the robustness and generalization of the model for the identification of terminal buds in different growth states. The results showed that, compared with the standard version of YOLOv5, the recognition accuracy of the improved YOLOv5 was significantly increased, with a precision of 95.55%, a recall of 95.84%, an F1-Score of 96.54%, and an mAP of 94.63%. Under the same experimental conditions, compared with other current mainstream algorithms (YOLOv3, Faster R-CNN, and PP-YOLO), the average precision and F1-Score of the improved YOLOv5 also increased by 9.51-28.19 percentage points and 15.92-32.94 percentage points, respectively. Overall, The improved YOLOv5 algorithm integrated with the attention network can accurately identify the terminal buds of densely-planted Chinese fir seedlings in UAV images and provide technical support for large-scale and automated counting and precision cultivation of Chinese fir seedlings.

Are there environmental benefits derived from coastal aquaculture of Sargassum fusiforme?

Seaweed farming may alleviate coastal eutrophication and acidification, and contribute to the coastal ecosystems. Sargassum fusiforme has nutritional and medicinal benefits, and its cultivation in China has expanded in recent years. However, the environmental benefits of coastal S. fusiforme farming to the surface seawater remain unclear. In this study, we compared cultured and non-cultured areas, during the culture and non-culture seasons, in the main S. fusiforme coastal growing area of China. The results showed that S. fusiforme farming slightly increased the dissolved oxygen content and pH of surface seawater but decreased the nutrient content and chemical oxygen demand. Furthermore, the eutrophication level of seawater decreased by 36% on average. In the later stage of cultivation, with large S. fusiforme biomass, the eutrophication level of the surface seawater decreased by >50%. In addition, S. fusiforme farming increased the phytoplankton biomass and diversity index, and in conjunction with environmental factors, altered the phytoplankton community structure. After the harvest of S. fusiforme, the dominant phytoplankton mostly comprised red tide microalgae, and their abundance was relatively large. Experiments and harvest evaluations showed that S. fusiforme cultivation removed 8082 t of carbon, 642 t of nitrogen, and 61 t of phosphorus from coastal China during one culture period. This study showed that large-scale cultivation of S. fusiforme can slightly improve coastal surface seawater quality by removing nutrients, alleviating eutrophication, and actively altering phytoplankton community structure. These environmental benefits may play an important role in maintaining the health of coastal ecosystems.

Exploring bacterioplankton communities and their temporal dynamics in the rearing water of a biofloc-based shrimp (Litopenaeus vannamei) aquaculture system.

Biofloc technology (BFT) has recently gained considerable attention as a sustainable method in shrimp aquaculture. In a successful BFT system, microbial communities are considered a crucial component in their ability to both improve water quality and control microbial pathogens. Yet, bacterioplankton diversity in rearing water and how bacterioplankton community composition changes with shrimp growth are rarely documented. In this study, the Pacific white shrimp, Litopenaeus vannamei was cultivated in a greenhouse-enclosed BFT system. Rearing water samples were collected on a weekly basis for 5 months (152 days) and water quality variables such as physicochemical parameters and inorganic nutrients were monitored. In parallel, 16S rRNA gene pyrosequencing was employed to investigate the temporal patterns of rearing-water microbiota. The productivity, survival rate, and feed conversion ratio were 3.2–4.4 kg/m3, 74%–89%, and 1.2–1.3, respectively, representing successful super-intensive cultures. The metataxonomic results indicated a highly dynamic bacterioplankton community, with two major shifts over the culture. Members of the phylum Planctomycetes dominated in rearing water during the early stages, while Actinobacteria dominated during the middle stages, and Chloroflexi and TM7 dominated during the late stages of culture. The bacterioplankton community fluctuated more in the beginning but stabilized as the culture progressed. Intriguingly, we observed that certain bacterioplankton groups dominated in a culture-stage-specific manner; these groups include Rhodobacteraceae, Flavobacteriaceae, Actinobacteria, and Chloroflexi, which either contribute to water quality regulation or possess probiotic potential. Altogether, our results indicate that an operationally successful BFT-based aquaculture system favors the growth and dynamics of specific microbial communities in rearing water. Our study expands the scientific understanding of the practical utilization of microbes in sustainable aquaculture. A thorough understanding of rearing-water microbiota and factors influencing their dynamics will help to establish effective management strategies.

3D-printed hyaluronic acid hydrogel scaffolds impregnated with neurotrophic factors (BDNF, GDNF) for post-traumatic brain tissue reconstruction.

Brain tissue reconstruction posttraumatic injury remains a long-standing challenge in neurotransplantology, where a tissue-engineering construct (scaffold, SC) with specific biochemical properties is deemed the most essential building block. Such three-dimensional (3D) hydrogel scaffolds can be formed using brain-abundant endogenous hyaluronic acid modified with glycidyl methacrylate by employing our proprietary photopolymerisation technique. Herein, we produced 3D hyaluronic scaffolds impregnated with neurotrophic factors (BDNF, GDNF) possessing 600 kPa Young’s moduli and 336% swelling ratios. Stringent in vitro testing of fabricated scaffolds using primary hippocampal cultures revealed lack of significant cytotoxicity: the number of viable cells in the SC+BDNF (91.67 ± 1.08%) and SC+GDNF (88.69 ± 1.2%) groups was comparable to the sham values (p > 0.05). Interestingly, BDNF-loaded scaffolds promoted the stimulation of neuronal process outgrowth during the first 3 days of cultures development (day 1: 23.34 ± 1.46 µm; day 3: 37.26 ± 1.98 µm, p < 0.05, vs. sham), whereas GDNF-loaded scaffolds increased the functional activity of neuron-glial networks of cultures at later stages of cultivation (day 14) manifested in a 1.3-fold decrease in the duration coupled with a 2.4-fold increase in the frequency of Ca2+ oscillations (p < 0.05, vs. sham). In vivo studies were carried out using C57BL/6 mice with induced traumatic brain injury, followed by surgery augmented with scaffold implantation. We found positive dynamics of the morphological changes in the treated nerve tissue in the post-traumatic period, where the GDNF-loaded scaffolds indicated more favorable regenerative potential. In comparison with controls, the physiological state of the treated mice was improved manifested by the absence of severe neurological deficit, significant changes in motor and orienting-exploratory activity, and preservation of the ability to learn and retain long-term memory. Our results suggest in favor of biocompatibility of GDNF-loaded scaffolds, which provide a platform for personalized brain implants stimulating effective morphological and functional recovery of nerve tissue after traumatic brain injury.

Titanium Surfaces Modified with Graphene Oxide/Gelatin Composite Coatings for Enhanced Antibacterial Properties and Biological Activities.

Titanium alloys have been widely used in orthopedic implants due to their excellent physicochemical properties and good biocompatibility. However, in practice, titanium implants may fail to integrate or develop an implant-centered infection. Because of its excellent mechanical properties, bone integrability, biocompatibility, antibacterial properties, and so on, graphene oxide is increasingly being used in the preparation of composite biomaterials. The percutaneous titanium implants are used as the research object in this project. To solve the integration of implant and tissue, a graphene oxide/gelatin (GO/gel) composite coating was used to optimize the implant surface. Bacterial and cell experiments were used to investigate the antimicrobial activity, biocompatibility, and regulation of macrophage polarization of GO/gel-modified titanium. According to our findings, GO/gel-modified titanium has a good bacteriostatic effect against Staphylococcus aureus. On the modified surface, L929 cells proliferated well and showed no cytotoxicity. Simultaneously, the GO/gel-modified titanium surface could inhibit macrophage adhesion and spread in the early stage of culture and showed a more obvious inflammatory decline in the late stage of culture. These findings implied that GO/gel-modified titanium is advantageous for resistant bacteria and tissue remolding.