A Fruit-Expressed MYB Transcription Factor Regulates Anthocyanin Biosynthesis in Atropa belladonna.

Anthocyanins are water-soluble flavonoid pigments that play a crucial role in plant growth and metabolism. They serve as attractants for animals by providing plants with red, blue, and purple pigments, facilitating pollination and seed dispersal. The fruits of solanaceous plants, tomato (Solanum lycopersicum) and eggplant (Solanum melongena), primarily accumulate anthocyanins in the fruit peels, while the ripe fruits of Atropa belladonna (Ab) have a dark purple flesh due to anthocyanin accumulation. In this study, an R2R3-MYB transcription factor (TF), AbMYB1, was identified through association analysis of gene expression and anthocyanin accumulation in different tissues of A. belladonna. Its role in regulating anthocyanin biosynthesis was investigated through gene overexpression and RNA interference (RNAi). Overexpression of AbMYB1 significantly enhanced the expression of anthocyanin biosynthesis genes, such as AbF3H, AbF3'5'H, AbDFR, AbANS, and Ab3GT, leading to increased anthocyanin production. Conversely, RNAi-mediated suppression of AbMYB1 resulted in decreased expression of most anthocyanin biosynthesis genes, as well as reduced anthocyanin contents in A. belladonna. Overall, AbMYB1 was identified as a fruit-expressed R2R3-MYB TF that positively regulated anthocyanin biosynthesis in A. belladonna. This study provides valuable insights into the regulation of anthocyanin biosynthesis in Solanaceae plants, laying the foundation for understanding anthocyanin accumulation especially in the whole fruits of solanaceous plants.

Transcriptome-Based WGCNA Analysis Reveals the Mechanism of Drought Resistance Differences in Sweetpotato (Ipomoea batatas (L.) Lam.).

Sweetpotato (Ipomoea batatas (L.) Lam.) is a globally significant storage root crop, but it is highly susceptible to yield reduction under severe drought conditions. Therefore, understanding the mechanism of sweetpotato resistance to drought stress is helpful for the creation of outstanding germplasm and the selection of varieties with strong drought resistance. In this study, we conducted a comprehensive analysis of the phenotypic and physiological traits of 17 sweetpotato breeding lines and 10 varieties under drought stress through a 48 h treatment in a Hoagland culture medium containing 20% PEG6000. The results showed that the relative water content (RWC) and vine-tip fresh-weight reduction (VTFWR) in XS161819 were 1.17 and 1.14 times higher than those for the recognized drought-resistant variety Chaoshu 1. We conducted RNA-seq analysis and weighted gene co-expression network analysis (WGCNA) on two genotypes, XS161819 and 18-12-3, which exhibited significant differences in drought resistance. The transcriptome analysis revealed that the hormone signaling pathway may play a crucial role in determining the drought resistance in sweetpotato. By applying WGCNA, we identified twenty-two differential expression modules, and the midnight blue module showed a strong positive correlation with drought resistance characteristics. Moreover, twenty candidate Hub genes were identified, including g47370 (AFP2), g14296 (CDKF), and g60091 (SPBC2A9), which are potentially involved in the regulation of drought resistance in sweetpotato. These findings provide important insights into the molecular mechanisms underlying drought resistance in sweetpotato and offer valuable genetic resources for the development of drought-resistant sweetpotato varieties in the future.

Resveratrol suppresses microglial activation and promotes functional recovery of traumatic spinal cord via improving intestinal microbiota.

Spinal cord injury (SCI) can change the intestinal microbiota pattern and corresponding metabolites, which in turn affect the prognosis of SCI. Among many metabolites, short-chain fatty acids (SCFAs) are critical for neurological recovery after SCI. Recent research has shown that resveratrol exerts anti-inflammatory properties. But it is unknown if the anti-inflammatory properties of resveratrol are associated with intestinal microbiota and metabolites. We thus investigate the alteration in gut microbiota and the consequent change of SCFAs following resveratrol treatment. The SCI mouse models with retention of gut microbiota (donor) and depletion of gut microbiota (recipient) were established. Fecal microbiota transplantation from donors to recipients was performed with intragastrical administration. Spinal cord tissues of mice were examined by H&E, Nissl, and immunofluorescence stainings. The expressions of the inflammatory profile were examined by qPCR and cytometric bead array. Fecal samples of mice were collected and analyzed with 16S rRNA sequencing. The results showed that resveratrol inhibited the microglial activation and promoted the functional recovery of SCI. The analysis of intestinal microbiota and metabolites indicated that SCI caused dysbiosis and the decrease in butyrate, while resveratrol restored microbiota pattern, reversed intestinal dysbiosis, and increased the concentration of butyrate. Both fecal supernatants from resveratrol-treated donors and butyrate suppressed the expression of pro-inflammatory genes in BV2 microglia. Our result demonstrated that fecal microbiota transplantation from resveratrol-treated donors had beneficial effects on the functional recovery of SCI. One mechanism of resveratrol effects was to restore the disrupted gut microbiota and butyrate.

Duraplasty of PHBV/PLA/Col membranes promotes axonal regeneration by inhibiting NLRP3 complex and M1 macrophage polarization in rats with spinal cord injury.

Duraplasty after decompression decreases the lesion size and scar formation, promoting better functional recovery, but the underlying mechanism has not been clarified. Here, we fabricated a series of poly(hydroxybutyrate-co-hydroxyvalerate)/polylactic acid/collagen (PHBV/PLA/Col) membranes and cultured them with VSC4.1 motor neurons. The material characteristics and in vitro biological characteristics were evaluated. In the subcutaneous implantation test, PHBV/PLA/COl scaffolds supported the cellular infiltration, microvasculature formation, and decreased CD86-positive macrophage aggregation. Following contusion spinal cord injury at T10 in Sprague-Dawley rats, durotomy was performed with allograft dura mater or PHBV/PLA or PHBV/PLA/Col membranes. At 3 days post-injury, Western blot assay showed decreased the expression of the NLRP3, ASC, cleaved-caspase-1, IL-1ß, TNF-α, and CD86 expression but increased the expression of CD206. Immunofluorescence demonstrated that duraplasty with PHBV/PLA/Col membranes reduced the infiltration of CD86-positive macrophages in the lesion site, decreased the glial fibrillary acidic protein expression, and increased the expression of NF-200. Moreover, duraplasty with PHBV/PLA/Col membranes improved locomotor functional recovery at 8 weeks post-injury. Thus, duraplasty with PHBV/PLA/Col membranes decreased the glial scar formation and promoted axon growth by inhibiting inflammasome activation and modulating macrophage polarization in acute spinal cord injury.

The diagnostic performance of conventional ultrasound and strain elastography in malignant soft tissue tumors.

OBJECTIVE: To investigate the diagnostic value of conventional ultrasound (US) and strain elastography (SE) in malignant soft tissue tumors. METHOD: A total of 83 soft tissue masses were included prospectively. US and SE imaging were performed at the same time. Two observers assessed the B mode, color Doppler, elastic scores (ES), strain ratio (SR), and SE size to B mode size (EI/B) ratio and compared the consistency of the data between the observers. According to the pathological diagnosis of resection, the cases were divided into malignant and nonmalignant groups. The diagnostic value of conventional US and SE in the prediction of malignant soft tissue tumors was assessed. RESULTS: The pathology results divided cases into 36 malignant lesions and 47 nonmalignant lesions. There was no statistically significant difference in gender, location, maximum diameter, echo, tail sign, cystic component, Doppler scores, or SR between the two groups (p > 0.05). However, significant differences between the two groups were found in age, depth, heterogeneity, edge, ES, and EI/B (p < 0.05). The biggest area under the receiver operating characteristics curve (0.934) was the combination model of age, heterogeneity, edge, ES, and EI/B, and the sensitivity and specificity were 0.861 and 0.957, respectively. CONCLUSIONS: Conventional US and SE are significant for the diagnosis of malignant soft tissue tumors, and SE can be used as a complementary technique to the characterization of STTs using conventional US.

Radiographic and clinical outcome of lateral lumbar interbody fusion for extreme lumbar spinal stenosis of Schizas grade D: a retrospective study.

BACKGROUND: Extreme lumbar spinal stenosis was thought to be a relative contraindication for lateral lumbar interbody fusion (LLIF) and was excluded in most studies. This is a retrospective study to analyze the radiographic and clinical outcome of LLIF for extreme lumbar spinal stenosis of Schizas grade D. METHODS: For radiographic analysis, we included 181 segments from 110 patients who underwent LLIF between June 2017 and December 2018. Lumbar spinal stenosis was graded according to Schizas' classification. Anterior and posterior disc heights, disc angle, foramen height, spinal canal diameter and central canal area were measured on CT and MRI. For clinical analysis, 18 patients with at least one segment of grade D were included. Visual analogue scale (VAS) and Oswestry disability index (ODI) scores were used to evaluate clinical outcome. Continuous variables were compared using Student's t-test, with P-values < 0.05 considered to indicate statistically significant differences. RESULTS: Among the 181 segments included for radiological evaluation, there were 23 grade A segments, 37 grade B segments, 103 grade C segments and 18 grade D segments. Postoperatively, the average change of midsagittal canal diameter of grade D was significantly greater than that of grade A, and not significantly different compared to grades B and C. As to the average change of disc height, bilateral foraminal height, disc angle and central canal area (CCA), grade D was not significantly different from the others. The average postoperative CCA of grade D was significantly smaller than the average preoperative CCA of grade C. Eighteen patients with grade D stenosis were followed up for an average of 19.61 ± 6.32 months. Clinical evaluation revealed an average improvement in the ODI and VAS scores for back and leg pain by 20.77%, 3.67 and 4.15 points, respectively. Sixteen of 18 segments with grade D underwent posterior decompression. CONCLUSION: The radiographic decompression effect of LLIF for Schizas grade D segments was comparable with that of other grades. Posterior decompression was necessary for LLIF to achieve a satisfactory clinical outcome for extreme lumbar spinal stenosis of Schizas grade D.

FoxA2 regulates the type II collagen-induced nucleus pulposus-like differentiation of adipose-derived stem cells by activation of the Shh signaling pathway.

Adipose tissue-derived stem cell (ADSC)-based therapy is promising for the treatment of intervertebral disc (IVD) degeneration, but the difficulty in inducing nucleus pulposus (NP)-like differentiation limits its clinical applications. Forkhead box (Fox)-A2 is an essential transcription factor for the formation of a normal NP. We demonstrated that type II collagen stimulates NP-like differentiation of ADSCs, partly by increasing the expression of FoxA2. We constructed FoxA2-overexpressing and -knockdown ADSCs by using lentiviral vectors. FoxA2 overexpression significantly enhanced NP-specific gene expression and the synthesis of glycosaminoglycan and collagen, whereas FoxA2 knockdown decreased NP-like differentiation and the expression of aggrecan and collagen II. The enhanced NP-like differentiation related to FoxA2 overexpression was partially rescued by an Shh signaling pathway inhibitor. In addition, FoxA2 inhibited the expression of Itg-α2 and further promoted NP-like differentiation induced by type II collagen. Furthermore, FoxA2-overexpressing ADSCs combined with type II collagen hydrogels promoted regeneration of degenerated NP in vivo. Our findings suggest that FoxA2 plays an essential role in the NP-like differentiation of ADSCs by activating the Shh signaling pathway.-Zhou, X., Ma, C., Hu, B., Tao, Y., Wang, J., Huang, X., Zhao, T., Han, B., Li, H., Liang, C., Chen, Q., Li, F. FoxA2 regulates the type II collagen-induced nucleus pulposus-like differentiation of adipose-derived stem cells by activation of the Shh signaling pathway.

Ligustrazine suppresses neuron apoptosis via the Bax/Bcl-2 and caspase-3 pathway in PC12 cells and in rats with vascular dementia.

The aim of this study was to examine the comprehensive neuroprotective mechanism of ligustrazine, which is extracted from Ligusticum Chuanxiong Hort., against vascular dementia (VD) in rats and apoptosis in oxygen and glucose deprivation (OGD) PC12 cells. Rats were subjected to bilateral common carotid artery occlusion (BCCAO) surgery and administered ligustrazine intragastrically for 6 weeks. At the end of the experiments, the hippocampal biomarkers brain-derived neurotrophic factor (BDNF), monocyte chemotactic protein 1 (MCP-1), and homocysteine (Hcy) were examined. In experiments in vitro, OGD PC12 cells were treated with ligustrazine for 0.5, 1, 3, 6, 12, or 24 h. The cell-released biomarkers BDNF, MCP-1, and Hcy were examined. Microscopy, acridine orange-ethidium bromide (AO/EB) staining, and flow cytometry assays were performed to investigate apoptosis. Cleaved caspase-3, Bcl-2 associated X protein (Bax), and B cell lymphoma 2 (Bcl-2) expression was examined using Western blot assays. The results showed that biomarkers, including MCP-1 and Hcy, were significantly increased in both the in vivo and in vitro models, while the BDNF level was significantly decreased compared with the sham or vehicle models. Microscopy, AO/EB staining, and flow cytometry analysis showed that severe cell damage occurred in OGD PC12 cells, and apoptosis played a major role in this environment. Further Western blot studies showed that the apoptosis-related Bax/Bcl-2 protein ratio and cleaved caspase-3 were significantly increased in the experiment. However, ligustrazine profoundly suppressed the imbalance of these biomarkers, reduced cell damage, decreased the Bax/Bcl-2, and downregulated cleaved caspase-3. Pro- and anti-apoptotic biomarkers of multiple pathways including BDNF, MCP-1, and Hcy played a joint role in triggering the activation of the mitochondria-related Bax/Bcl-2 and caspase-3 apoptosis pathway in VD. Ligustrazine attenuated VD by comprehensively regulating BDNF, MCP-1, and Hcy and inactivating the Bax/Bcl-2 and caspase-3 apoptosis pathway. Our data provide novel insight into ligustrazine, which is a promising neuroprotective agent for VD disease treatment strategies. © IUBMB Life, 70(1):60-70, 2018.

Is Delayed Surgery After Unsuccessful Conservative Treatment Beneficial for Spinal Cord Injury Following Whiplash? A Retrospective Study in Elderly Patients.

BACKGROUND The aim of this study was to investigate the clinical outcomes of early and delayed surgery in cervical spinal cord injury following whiplash in elderly patients. MATERIAL AND METHODS Our retrospective review identified elderly patients (≥65 years old) with spinal cord injury following whiplash injury from 2006 to 2015. The neck disability index (NDI), modify Japanese Orthopedics Association (mJOA) score, and visual analogue scale (VAS) score were used to evaluate clinical outcomes preoperatively and during follow-up. The angular range of motion (ROM) for C2-C7 was measured by dynamic flexion and extension lateral cervical radiographs at each observation follow-up time point. Treatment-related complication data were collected, and the complication rates analyzed. RESULTS Forty-six elderly patients (age range 65-82 years) with spinal cord injury following whiplash injury were enrolled in this study. Twenty-four patients underwent early surgery and twenty-two patients (age range 65-78 years) received delayed surgery after conservative treatment failure. During the follow-up period, both groups had significant post-operative improvement in NDI, mJOA, and VAS scores (p<0.05), although the early surgery group had better outcomes than the delayed surgery after unsuccessful conservative treatment group (p<0.05). However, on average, no significant differences in sagittal C2-C7 ROM between the two groups were found during follow-up. Comparison of the two groups showed the incidences of pneumonia and deep vein thrombosis were significantly higher in the delayed surgery group (p<0.05). CONCLUSIONS This study indicated that delayed surgery after unsuccessful conservative treatment provided excellent clinical results for elderly patients; however, timely surgical intervention is necessary for neurological symptom deterioration.

The application of SVR model in the improvement of QbD: a case study of the extraction of podophyllotoxin.

In order to make a further optimization of process design via increasing the stability of design space, we brought in the model of Support Vector Regression (SVR). In this work, the extraction of podophyllotoxin was researched as a case study based on Quality by Design (QbD). We compared the fitting effect of SVR and the most used quadratic polynomial model (QPM) in QbD, and an analysis was made between the two design spaces obtained by SVR and QPM. As a result, the SVR stayed ahead of QPM in prediction accuracy, the stability of model and the generalization ability. The introduction of SVR into QbD made the extraction process of podophyllotoxin well designed and easier to control. The better fitting effect of SVR improved the application effect of QbD and the universal applicability of SVR, especially for non-linear, complicated and weak-regularity problems, widened the application field of QbD.

The imbalance between TIMP3 and matrix-degrading enzymes plays an important role in intervertebral disc degeneration.

It is well-known that one of the most important features of intervertebral disc degeneration (IDD) is the extracellular matrix (ECM) degradation. Collagen and aggrecan are major components of ECM; the degradation of ECM in intervertebral discs (IVDs) is closely related to the activities of collagenase and aggrecanase. TIMP-3 is the most efficient inhibitor of aggrecanase in IVD. However, only few studies focus on the potential relationship between TIMP-3 and IDD. In our study, we found TIMP-3 gene expression was decreased after stimulating with LPS in rat nucleus pulposus (NP) cells. Then we used a lentivirus vector to reconstruct rat NP cells which high expressed TIMP-3 gene (LV-TIMP3). The upregulation of MMPs and ADAMTSs induced by LPS was significantly inhibited in LV-TIMP3 cells. After overexpression of TIMP-3, the aggrecan breakdown caused by LPS was also reduced in both monolayer culture and three-dimension culture model. To further study the relation between TIMP-3 and IDD, we collected human NP tissue samples of different degenerative degrees. Real-time PCR and immunohistochemical staining showed that the expression of TIMP-3 was negatively correlated with the degree of intervertebral disc degeneration, while MMP-1 and ADAMTS-4 were markedly increased in degenerative IVD. Taken together, our results suggest that the imbalance between aggrecanase and TIMP-3 may play an important role in the pathogenesis of IDD and therefore be a potential therapeutic target for treating IDD.

Rabbit conjunctivae edema and release of NO, TNF-α, and IL-1ß from macrophages induced by fractions and esculentosides isolated from Phytolacca americana.

CONTEXT: The roots of Phytolacca americana L. (Phytolaccaceae) may be toxic. Despite heated controversy over the toxic compounds of P. americana, especially esculentosides, relevant studies remain scarce. OBJECTIVE: The objective of this study is to screen the toxic fractions and compounds of P. americana, to determine the controlling indices, and to provide evidence for unraveling the mechanism. MATERIALS AND METHODS: Petroleum ether (PE), CH2Cl2, n-BuOH, and water fractions were isolated from 70% ethanol extract of P. americana. The n-BuOH fraction was dissolved in 50% ethanol and precipitated by adding ethyl ether. The resultant supernatants and precipitates were referred to as SUPs and SEDs fractions, respectively. SUPs fraction was separated by column chromatography into four main stimulating esculentosides that were identified by HR-ESI/MS and NMR as EsA, EsB, EsC, and EsF. The irritating effects of esculentosides on rabbit conjunctivae (500 µg/eye) was observed by pathological examination and those on macrophages (5, 25, 50 and 100 µg/mL) were evaluated by detecting changes of NO, TNF-α, and IL-1ß levels. RESULTS AND DISCUSSION: n-BuOH, SUP fractions, and EsC induced severe conjunctival edema. The four esculentosides induced dose-dependent releases of proinflammatory mediators NO, TNF-α, and IL-1ß from macrophages, and releasing amounts peaked after 2 h of treatment. EsC and EsF induced macrophages to release mediators most significantly. EsC (50 µg/mL) functioned more effectively than EsF did, and similarly n-BuOH and SUPs fractions functioned more effectively than the esculentoside mixture. Thus, the four esculentosides exerted proinflammatory effects synergistically. CONCLUSION: All extracted esculentosides, especially EsC, induced inflammatory stimulation. Phytolacca americana-induced irritation of the gastrointestinal tract may be associated with esculentosides such as EsC.

[Antagonistic effect of gingerols against TNF-α release, ROS overproduction and RIP3 expression increase induced by lectin from Pinellia ternata].

To explore the antagonistic effect of gingerols against the inflammation induced by lectin from Pinellia ternata. In this study, ELISA method was used to determine the effect of different extracts from gingerols on the release of inflammatory factor TNF-α from macrophages induced by lectin from P. ternata. The fluorescence probe was used to determine the effect of gingerols on the changes in ROS of macrophages induced by lectin from P. ternata. The western-blot method was applied to study the effect of gingerols on the increase in expression of cell receptor interacting protein RIP3 in macrophages induced by lectin from P. ternata. The scanning electron microscope (SEM) was used to study the effect of gingerols on morphological changes in macrophages induced by lectin from P. ternata. According to the results, gingerols can significantly inhibit the release of inflammatory factor from macrophages induced by lectin from P. ternata, ROS overproduction and increase in RIP3 expression. SEM results showed that gingerols can inhibit the cytomorphosis and necrocytosis induced by lectin from P. ternata. Fresh ginger's detoxication may be related to gingerols' effects in inhibiing release of inflammatory factor, ROS overproduction and increase in RIP3 expression caused by macrophages induced by lectin from P. ternata, which are mainly inflammatory development.

Guided bone regeneration using chitosan-collagen membranes in dog dehiscence-type defect model.

PURPOSE: The purpose of the present study was to compare a newly developed chitosan-collagen membrane (CCM) with a standard collagen membrane (SCM) regarding their effects on guided bone regeneration. MATERIALS AND METHODS: The right mandibular premolars and first molar were extracted from 12 beagle dogs. Four months later, acute buccal dehiscence-type defects (4 × 3 mm in height and width) were surgically created after implant site preparation. The defects were randomly assigned to 4 different groups: CCM-1 (weight ratio of chitosan to collagen of 40:1), CCM-2 (weight ratio of chitosan to collagen of 20:1), SCM, and vehicle control. The dogs were sacrificed after 4, 8, and 12 weeks of healing for radiographic examination, histologic observation, and histometric analysis. RESULTS: The membrane-treated sites showed more bone formation than the control sites, although no statistically significant differences were found between the membrane-treated sites and the control sites for new bone-to-implant contact and new bone-filled area at any point. At 8 weeks, the new bone height for the membrane-treated sites was significantly greater statistically than that of the untreated group (P < .05). At 12 weeks, the CCM-1 group showed significantly greater new bone height (1.91 ± 0.25 mm) than the untreated group (1.20 ± 0.34 mm; P < .05). However, the CCMs did not show any statistically significant differences compared with the SCMs for any assessed parameter. CONCLUSIONS: The results of the present study have shown that the developed CCMs can enhance bone regeneration and could be a candidate for use in guided bone regeneration.

Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model.

PURPOSE: The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model. METHODS: Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically. RESULTS: The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups. CONCLUSIONS: The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.

Synthesis and biological activity of some bile acid-based camptothecin analogues.

In an effort to decrease the toxicity of camptothecin (CPT) and improve selectivity for hepatoma and colon cancer cells, bile acid groups were introduced into the CPT 20 or 10 positions, resulting in the preparation of sixteen novel CPT-bile acid analogues. The compounds in which a bile acid group was introduced at the 20-hydroxyl group of CPT showed better cytotoxic selectivity for human hepatoma and colon cancer cells than for human breast cancer cells. Fluorescence microscopy analysis demonstrated that one compound (E2) entered human hepatoma cells more effectively than it did human breast cancer cells. Compound G4 exhibited the best anti-tumour activity in vivo. These results suggested that introduction of a bile acid group at the 20-position of CPT could decrease toxicity in vivo and improve selectivity for hepatoma cells.

Interfacial interactions between spider silk protein and cellulose studied by molecular dynamics simulation.

CONTEXT: Due to their excellent biocompatibility and degradability, cellulose/spider silk protein composites hold a significant value in biomedical applications such as tissue engineering, drug delivery, and medical dressings. The interfacial interactions between cellulose and spider silk protein affect the properties of the composite. Therefore, it is important to understand the interfacial interactions between spider silk protein and cellulose to guide the design and optimization of composites. The study of the adsorption of protein on specific surfaces of cellulose crystal can be very complex using experimental methods. Molecular dynamics simulations allow the exploration of various physical and chemical changes at the atomic level of the material and enable an atomic description of the interactions between cellulose crystal planes and spider silk protein. In this study, molecular dynamics simulations were employed to investigate the interfacial interactions between spider silk protein (NTD) and cellulose surfaces. Findings of RMSD, RMSF, and secondary structure showed that the structure of NTD proteins remained unchanged during the adsorption process. Cellulose contact numbers and hydrogen bonding trends on different crystalline surfaces suggest that van der Waals forces and hydrogen bonding interactions drive the binding of proteins to cellulose. These findings reveal the interaction between cellulose and protein at the molecular level and provide theoretical guidance for the design and synthesis of cellulose/spider silk protein composites. METHODS: MD simulations were all performed using the GROMACS-5.1 software package and run with CHARMM36 carbohydrate force field. Molecular dynamics simulations were performed for 500 ns for the simulated system.

Molecular insights into inhibiting effects of lignin on cellulase investigated by molecular dynamics simulation.

The hydrolysis of lignocellulose into fermentable monosaccharides using cellulases represents a critical stage in lignocellulosic bioconversion. However, the inactivation of cellulase in the presence of lignin is attributed to the high cost of biofinery. To address this challenge, a comprehensive investigation into the structure-function relationship underlying lignin-driven cellulase inactivation is essential. In this study, molecular docking and molecular dynamics (MD) simulations were employed to explore the impacts of lignin fragments on the catalytic efficiency of cellulase at the atomic level. The findings revealed that soluble lignin fragments and cellulose could spontaneously form stable complexes with cellulase, indicating a competitive binding scenario. The enzyme's structure remained unchanged upon binding to lignin. Furthermore, specific amino acid residues have been identified as involved in interactions with lignin and cellulose. Hydrophobic interactions were found to dominate the binding of lignin to cellulase. Based on the mechanisms underlying the interactions between lignin fragments and cellulase, decreased hydrophobicity and change in the charge of lignin may mitigate the inhibition of cellulase. Furthermore, site mutations and chemical modification are also feasible to improve the efficiency of cellulase. This study may contribute valuable insights into the design of more lignin-resistant enzymes and the optimization of lignocellulosic pretreatment technologies.Communicated by Ramaswamy H. Sarma.

High resolution terahertz ATR frequency-domain spectroscopy for monitoring spinal cord injury in rats.

Traumatic spinal cord injury (SCI) can lead to permanent neurological impairment, underscoring the urgency of regular therapeutic intervention and monitoring. In this study, we propose a new strategy for monitoring spinal cord injury through serum based on high-resolution THz attenuated total reflection frequency domain spectroscopy (THz-ATR-FDS). We demonstrated serum spectral differences at different time points after experimental SCI in rats. We also studied the relationship between serum lipid concentration and the time of SCI, which revealed the potential of lipid molecules as biomarkers of SCI. In addition, based on the principal component analysis (PCA) and least squares regression (LSR) models, the quantitative relationship between the refractive index spectrum and lipid concentration in serum was automatically analyzed. This work highlights terahertz spectroscopy as a promising tool for label-free, periodic, and efficient monitoring of SCI.

Functional divergence of two arginine decarboxylase genes in tropane alkaloid biosynthesis and root growth in Atropa belladonna.

Putrescine, produced via the arginine decarboxylase (ADC)/ornithine decarboxylase (ODC)-mediated pathway, is an initial precursor for polyamines metabolism and the root-specific biosynthesis of medicinal tropane alkaloids (TAs). These alkaloids are widely used as muscarinic acetylcholine antagonists in clinics. Although the functions of ODC in biosynthesis of polyamines and TAs have been well investigated, the role of ADC is still poorly understood. In this study, enzyme inhibitor treatment showed that ADC was involved in the biosynthesis of putrescine-derived metabolites and root growth in Atropa belladonna. Further analysis found that there were six ADC unigenes in the A. belladonna transcriptome, with two of them, AbADC1 and AbADC2, exhibiting high expression in the roots. To investigate their roles in TAs/polyamines metabolism and root growth, RNA interference (RNAi) was used to suppress either AbADC1 or AbADC2 expression in A. belladonna hairy roots. Suppression of the AbADC1 expression resulted in a significant reduction in the putrescine content and hairy root biomass. However, it had no noticeable effect on the levels of N-methylputrescine and the TAs hyoscyamine, anisodamine, and scopolamine. On the other hand, suppression of AbADC2 expression markedly reduced the levels of putrescine, N-methylputrescine, and TAs, but had no significant effect on hairy root biomass. According to ß-glucuronidase (GUS) staining assays, AbADC1 was mainly expressed in the root elongation and division region while AbADC2 was mainly expressed in the cylinder of the root maturation region. These differences in expression led to functional divergence, with AbADC1 primarily regulating root growth and AbADC2 contributing to TA biosynthesis.