[Progress in research and development of soft tissue three-dimensional bioprinting and its supporting equipment].

As a cutting-edge technology of tissue engineering, three-dimensional bioprinting can accurately fabricate biomimetic tissue, which has made great progress in the field of hard tissue printing such as bones and teeth. Meanwhile, the research on soft tissue bioprinting is also developing rapidly. This article mainly discussed the development progress in various bioprinting technologies and supporting equipment including printing software, printing hardware, supporting consumables, and bioreactors for soft tissue three-dimensional bioprinting, and made a prospect for the future research and development direction of soft tissue three-dimensional bioprinting.

Long-term use of Lacticaseibacillus paracasei N1115 from early life alleviates high-fat-diet-induced obesity and dysmetabolism in mice.

Obesity has become one of the most serious public health problems worldwide, and an increasing number of studies indicate that the gut microbiota can affect host metabolism. Therefore, the present study was conducted to evaluate whether long-term use of probiotics can alleviate host obesity and metabolism by altering gut microbiota. The high-fat diet (HFD) starting from weaned period led to higher levels of visceral fat and a significantly heavier liver in male mice. Moreover, HFD resulted in disorders of glucose and lipid metabolism, changes in insulin-resistance indices (IR), and an increase in serum insulin and leptin in mice. Of note, 15 weeks use of Lacticaseibacillus paracasei N1115 decreased visceral fat, liver weight, serum levels of insulin and leptin, and IR and alleviated lipid dysmetabolism. HFD resulted in a significant increase in the relative abundance of Bilophila, Lachnoclostridium, and Blautia and may decrease the faecal short-chain fatty acid (SCFA) levels in mice; in turn, treatment with the potential probiotic strain L. paracasei N1115 protected mice from these negative effects. HFD significant impaired the physiology of the host especially in male mice and dramatically changed the composition of host gut microbiota. However, the use of potential probiotic strain, such as L. paracasei N1115, may prevent these impairments due to HFD via effecting the host gut microbiota and SCFA.

[Research advances on the application of natural and recombinant collagen in wound repair].

Collagen is a macromolecular protein constituting the extracellular matrix of animal connective tissue, which has been widely used and developed in fields of biomedicine, tissue engineering, food, and cosmetics. Due to its advantages such as abundant sources and good biocompatibility, low immunogenicity, and degradability, collagen can be used as a dressing or tissue engineering scaffold for wound repair. According to the source of materials, collagen can be divided into natural collagen and recombinant collagen. Natural collagen is mainly extracted directly from mammals and fish; recombinant collagen is obtained based on genetic engineering technology, and its sources include recombinant expression systems of microorganisms, animals, and plants. This paper summarizes the sources of collagen, and the roles, advantages, and disadvantages of different sources of collagen in wound repair, the particularity and superiority of collagen combined with three-dimensional printing technology in wound repair, the impact of market norms of China's collagen industry on the field of wound repair, and explains the precautions for the development of collagen-related products, aiming to provide new ideas for selecting a suitable source of collagen for wound repair.

Quantitative determination of endogenous cardiolipin in rat cerebral tissues by high-performance liquid chromatography using standard addition method.

Cardiolipin is an important cellular component, and its normal level is a key prerequisite for maintaining the structure and function of mitochondria. To accurately quantify endogenous cardiolipin content in mitochondria, a standard addition method (SAM) was developed to establish a high-performance liquid chromatographic (HPLC) technique that is both reliable and accurate. Increasing amounts of cardiolipin standards were added to a constant amount of isolated mitochondria prior to the extraction procedure, and the two were extracted together. By limiting the interference effects that occur to within an acceptable range in an analytical system examined, this procedure ensures an ideal match of the sample composition in the standards, even if the composition is extremely complex or completely unknown. Then, the desired results can be obtained by extrapolation. As such, the authentic content of the endogenous cardiolipin can be obtained with greater accuracy than with classical detection methods, e.g. external standard calibration (ESC) and internal standard calibration (ISC). This method provides an excellent means of quantifying endogenous substances in living cells. The authors expect this method to be useful for researchers working on mitochondria-related mechanisms, cell survival-related mechanisms and similar topics.

Exogenous nitric oxide negatively regulates the S-nitrosylation p38 mitogen-activated protein kinase activation during cerebral ischaemia and reperfusion.

AIMS: A number of studies have suggested that nitric oxide (NO) plays an important role in the reactive phosphorylation of p38MAPKα (p38). However, whether S-nitrosylation of p38 is activated by NO and the details remain unclear. The aim of the present work was to assess the activation of p38, the S-nitrosylation site and the p38 signalling pathway in rat hippocampus and in HEK293 cell induced by exogenous NO. METHODS: Primary hippocampal cultures, HEK293 cells and rat model of cerebral ischaemia/reperfusion (brain ischaemia was induced by four-vessel occlusion procedure) were used in this study. Biotin-switch method and immunoblotting were performed to study the S-nitrosylation and phosphorylation of p38, and neuronal loss was observed by histology. RESULTS: Endogenous NO increased p38 phosphorylation and S-nitrosylation, and the activation of p38 was dependent on the S-nitrosylation of Cys-211, which was critical for the NO-mediated activation of p38. The exogenous NO donor sodium nitroprusside, S-nitrosoglutathione, 7-nitroindazole, the inhibitor of the neuronal nitric oxide synthase, inhibited the activation of p38 signal pathway induced by cerebral ischaemia/reperfusion and attenuated the damage in rat hippocampal neurones. Moreover, the N-methyl-D-aspartate receptor (NMDAR) is probably involved in the p38 activation process of S-nitrosylation and phosphorylation. CONCLUSION: Endogenous NO induces the S-nitrosylation and phosphorylation of p38 and mediates p38 signalling pathway by NMDAR, and as exogenous NO inhibits this process and is neuroprotective in rat cerebral ischaemia/reperfusion, it may make a contribution to stroke therapy.

Neuroprotection of ethanol against ischemia/reperfusion-induced brain injury through decreasing c-Jun N-terminal kinase 3 (JNK3) activation by enhancing GABA release.

Our latest study indicated that ethanol could attenuate cerebral ischemia/reperfusion-induced brain injury through activating Ionotropic glutamate receptors Kainate Family (Gluk1)-kainate (KA) receptors and gamma-aminobutyric acid (GABA) receptors. However, the possible mechanism of the neuroprotective effects of ethanol remains unclear. In this study we report that ethanol shows neuroprotective effects against ischemic brain injury through enhancing GABA release and then decreasing c-Jun N-terminal kinase 3 (JNK3) activation. Electrophysiologic recording indicated that ethanol enhances GABA release from presynaptic neurons and the released GABA subsequently inhibits the KA receptor-mediated whole-cell currents. Moreover, our data show that ethanol can inhibit the increased assembly of the Gluk2-PSD-95-MLK3 (postsynaptic density protein-95, PSD-95 and mixed-lineage kinase 3, MLK3) module induced by cerebral ischemia and the activation of the MLK3-MKK4/7-JNK (mitogen-activated protein kinase kinase 4/7, MKK4/7) cascade. Pretreatment of the GABA(A) receptor antagonist bicuculline and antagonist of VGCC (a broad-spectrum blocker of the voltage-gated calcium channel [VGCC]) Chromic (CdCl(2)) can demolish the neuroprotective effects of ethanol. The results suggest that during ischemia-reperfusion, ethanol may activate presynaptic Gluk1-KA and facilitate Ca(2+)-dependent GABA release. The released GABA activates postsynaptic GABA(A) receptors, which suppress the ischemic depolarization and decrease the association of signaling module Gluk2-PSD-95-MLK3 induced by the activation of postsynaptic Gluk2-KA receptors. There is a raised possibility that ethanol inhibiting the JNK3 apoptotic pathway (MLK3/MKK4/7/JNK3/c-Jun/Fas-L) performs a neuroprotective function against ischemic brain injury.

Effects of asiaticoside on the expression of Smad protein by normal skin fibroblasts and hypertrophic scar fibroblasts.

BACKGROUND: The precise mechanism of asiaticoside in molecular and gene expression levels of Smad protein and mRNA still remains unknown. We hypothesised that asiaticoside might inhibit the formation of hypertrophic scarring by affecting the expression of Smad protein and interfering with the Smad signalling pathway. AIMS: To investigate the effects of asiaticoside on the expression of Smad protein by hypertrophic scar fibroblasts (HSFs) and to clarify the mechanism of asiaticoside in scar treatment. METHODS: Normal skin fibroblasts and HSFs were exposed to various concentrations of asiaticoside in serum-free medium for 72 h, then immunocytochemistry was used to examine the localization and expression of phosphorylated Smad2 and Smad7. The expression of Smad protein was studied both at the transcriptional and post-transcriptional levels, using conventional reverse transcription PCR and Western blotting. RESULTS: Asiaticoside markedly enhanced the expression of inhibitory Smad7, but it had no effect on the expression of Smad2. Further study revealed that asiaticoside could induce Smad7 to enter the cytoplasm from the nucleus. CONCLUSIONS: Asiaticoside inhibits scarring probably by enhancing the expression of inhibitory Smad7, and is a potential treatment for scarring.

Antifouling and antibacterial compounds from the gorgonians Subergorgia suberosa and Scripearia gracillis.

In this study, we investigated the potential antilarval and antibacterial activity of secondary metabolites of the gorgonians Subergorgia suberosa and Scripearia gracillis from the South China Sea. Fresh specimens of these two gorgonian corals were collected from a shallow reef in Sanya Bay of Hainan Island and extracted with different solvents. Antilarval activity of the chemical extracts and pure compounds was evaluated in settlement inhibition assays with laboratory-reared Balanus amphitrite and Bugula neritina larvae, while antibacterial activity was assessed with disc diffusion bioassay on growth inhibition of 15 marine bacterial species. Using bioassay-guided procedures, we purified and identified nine compounds. The most potent metabolites produced by these gorgonian corals were subergorgic acid and pregn-4-ene-3, 20-dione extracted from S. suberosa. Our results show that the gorgonian coral S. suberosa and S. gracillis can produce potent anti-fouling compounds that deserve further exploration.

Effect of agitation on violacein production in Pseudoalteromonas luteoviolacea isolated from a marine sponge.

AIMS: Experiments were designed to investigate the effect of agitation on the production of violacein by a marine bacterium Pseudoalteromonas luteoviolacea. METHODS AND RESULTS: A marine sponge-associated bacterium, P. luteoviolacea, was grown at different agitation speeds. Agitation did not have a significant effect on bacterial growth, but had a profound effect on the size of bacterial aggregate. The production of violacein was the highest under stagnant conditions and decreased with the increase of the agitation speed. CONCLUSIONS: Agitation affected the aggregation of bacterial cells, which, in turn, affected violacein production by P. luteoviolacea. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that P. luteoviolacea produced the highest amount of violacein when it was cultured under stagnant conditions.

Source seasonality of polycyclic aromatic hydrocarbons (PAHs) in a subtropical city, Guangzhou, South China.

Mega-cities are large sources of air pollution on a regional base. Differences in energy structures, geographical settings and regional climate features lead to a large variety of air pollution sources from place to place. To understand the seasonality of air pollution sources is critical to precise emission inventories and a sound protection of human health. Based on a year-round dataset, the sources of PAHs in the air of Guangzhou were drawn by principal factor analysis (PCA) in combination with diagnostic ratios, and the seasonality of these sources were analyzed by PCA/MLR (multiple linear regressions) and discussed. The average total gaseous and particulate PAHs concentrations were 313 and 23.7 ng m(-3), respectively, with a higher concentration of vapor PAHs in summer and particulate PAHs in winter. In addition to vehicle exhaust, which contributed 69% of the particulate PAHs, coal combustion was still an important source and contributed 31% of the particulate PAHs. Relatively constant contribution from coal combustion was found through the year, implying that coal combustion in power plants was not a seasonally dependent source. Evaporation from contaminated ground may be an important source of light PAHs in summer, providing an average contribution of 68% to the total PAHs in this study. By comparing the PAH concentrations and meteorological parameters, we found that higher concentrations of particulate PAHs in winter resulted from enhanced vehicle exhaust under low temperature and accumulation of pollutants under decreased boundary layer, slower wind speed, and long-term dryness conditions. It is suggested that the typical subtropical monsoon climate in South China, cool and dry in winter, hot and humid in summer, may play a key role in controlling the source seasonality (by enhancing vehicle exhaust in winter, ground evaporation in summer), and hence the ambient concentrations of PAHs in the air.

Sedimentary record of polycyclic aromatic hydrocarbons in a sediment core from the Pearl River Estuary, South China.

Owing to the hydrodynamic and sedimentation conditions, the western shoal of the Pearl River Estuary (PRE) is known to be an important sink of terrestrial substances including particle-associated pollutants from the Pearl River Delta (PRD) region. In this study, we report the sedimentary record of polycyclic aromatic hydrocarbons (PAHs) during the 20(th) century in a sediment core from the western shoal of the PRE. The summation PAH concentration ranged from 59 ng g(-1) to 330 ng g(-1) in the core with two distinct peaks. An initial increase of summation PAH concentration was found around the 1860s. The amounts of PAHs remained relatively constant for roughly 100 years, followed by the first peak in the 1950s. Then, there was a decrease in PAH concentration and flux in the 1960s and 1970s. A sharp increase of PAH concentration was observed in the early 1980s with a maximum concentration in the 1990s. The PAH diagnostic ratios indicated that the PAHs in the sediment core were mainly of pyrolytic origin, and that atmospheric deposition and land runoff may serve as the important pathways for PAHs input to the sediment. The Gross Domestic Product (GDP) was used as an index of socioeconomic development in the PRD region, which was correlated positively with the changes of PAH concentration and flux in the sediment core. The rapid increase in vehicle numbers and energy consumption in the region in the last two decades may have contributed to the rapid PAH increase since the early 1980s. The results clearly elucidated the impact of regional economic development on the estuarine environment.

Heavy metals in agricultural soils of the Pearl River Delta, South China.

There is a growing public concern over the potential accumulation of heavy metals in agricultural soils in China owing to rapid urban and industrial development and increasing reliance on agrochemicals in the last several decades. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but elevated heavy metal uptake by crops may also affect food quality and safety. The present study is aimed at studying heavy metal concentrations of crop, paddy and natural soils in the Pearl River Delta, one of the most developed regions in China. In addition, some selected soil samples were analyzed for chemical partitioning of Co, Cu, Pb and Zn. The Pb isotopic composition of the extracted solutions was also determined. The analytical results indicated that the crop, paddy and natural soils in many sampling sites were enriched with Cd and Pb. Furthermore, heavy metal enrichment was most significant in the crop soils, which might be attributed to the use of agrochemicals. Flooding of the paddy soils and subsequent dissolution of Mn oxides may cause the loss of Cd and Co through leaching and percolation, resulting in low Cd and Co concentrations of the paddy soils. The chemical partitioning patterns of Pb, Zn and Cu indicated that Pb was largely associated with the Fe-Mn oxide and residual fractions, while Zn was predominantly found in the residual phase. A significant percent fraction of Cu was bound in the organic/sulphide and residual phases. Based on the 206Pb/207Pb ratios of the five fractions, it was evident that some of the soils were enriched with anthropogenic Pb, such as industrial and automobile Pb. The strong associations between anthropogenic Pb and the Fe-Mn oxide and organic/sulphide phases suggested that anthropogenic Pb was relatively stable after deposition in soils.