Enforced HCELL Expression Enhances Bone Marrow Stromal Cells Homing and Amelioration of Cerebral Ischemia-Reperfusion Injury via induction of PGE2.

Ischemic stroke (IS) is a significant and potentially life-threatening disease with limited treatment options, often resulting in severe disability. Bone marrow stromal cells (BMSCs) transplantation has exhibited promising neuroprotection following cerebral ischemia-reperfusion injury (CIRI). However, the effectiveness is hindered by their low homing rate when administered through the vein. In this study, we aimed to enhance the homing ability of BMSCs through lentivirus transfection to express fucosyltransferase 7. This glycosylation engineered CD44 on BMSCs to express hematopoietic cell E-selectin/L-selectin ligand (HCELL), which is the most potent E-selectin ligand. Following enforced HCELL expression, the transplantation of BMSCs was then evaluated in a middle cerebral artery occlusion (MCAO) model. Results showed that HCELL+BMSCs significantly ameliorated neurological deficits and reduced the volume of cerebral infarction. Furthermore, the transplantation led to a decrease in apoptosis by up-regulating BCL-2 and down-regulating BAX, also reduced the mRNA levels of inflammatory factors, such as interleukin-1ß (IL-1ß), IL-2, IL-6 and tumor necrosis factor-alpha (TNF-α) in the ischemic brain tissue. Notably, enforced HCELL expression facilitated the migration of BMSCs towards cerebral ischemic lesions and their subsequent transendothelial migration through the up-regulation of PTGS-2, increased production of PGE2 and activation of VLA-4. In summary, our study demonstrates that transplantation of HCELL+BMSCs effectively alleviates CIRI, and that enforced HCELL expression enhances the homing of BMSCs to cerebral ischemic lesions and their transendothelial migration via PTGS-2/PGE2/VLA-4. These findings indicate that enforced expression of HCELL on BMSCs could serve as a promising therapeutic strategy for the treatment of ischemic stroke.

ANP32B-mediated repression of p53 contributes to maintenance of normal and CML stem cells.

Proper regulation of p53 signaling is critical for the maintenance of hematopoietic stem cells (HSCs) and leukemic stem cells (LSCs). The hematopoietic cell-specific mechanisms regulating p53 activity remain largely unknown. Here, we demonstrate that conditional deletion of acidic leucine-rich nuclear phosphoprotein 32B (ANP32B) in hematopoietic cells impairs repopulation capacity and postinjury regeneration of HSCs. Mechanistically, ANP32B forms a repressive complex with p53 and thus inhibits the transcriptional activity of p53 in hematopoietic cells, and p53 deletion rescues the functional defect in Anp32b-deficient HSCs. Of great interest, ANP32B is highly expressed in leukemic cells from patients with chronic myelogenous leukemia (CML). Anp32b deletion enhances p53 transcriptional activity to impair LSC function in a murine CML model and exhibits synergistic therapeutic effects with tyrosine kinase inhibitors in inhibiting CML propagation. In summary, our findings provide a novel strategy to enhance p53 activity in LSCs by inhibiting ANP32B and identify ANP32B as a potential therapeutic target in treating CML.

Application of a novel nylon needle filter-based solid-phase extraction device to determination of 1-hydroxypyrene in urine.

In this work, a simple and miniaturized solid-phase extraction device was constructed by connecting a commercial nylon needle filter to a syringe, which was applied for extracting 1-hydroxypyrene from a urine sample via hydrophobic and hydrogen bond interactions. The nylon membrane in the needle filter acted as the solid-phase extraction adsorbent, meanwhile, it filtered the particles in the urine sample. To obtain high extraction efficiency, key parameters influencing extraction recovery were investigated. The entire pretreatment process was accomplished within 5 min under the optimal conditions. By coupling high-performance liquid chromatography-ultraviolet, a rapid, low-cost, and convenient nylon needle filter-based method was established for the analysis of 1-hydroxypyrene in a complex urine matrix. Within the linearity range of 0.2-1000 µg/L, the method exhibited a satisfactory correlation coefficient (R = 0.9999). The limit of detection was 0.06 µg/L, and the recoveries from urine sample spiked with three concentrations (5, 20, and 100 µg/L) ranged from 105.8% to 113.1% with the relative standard deviations less than 6.7% (intra-day, n = 6) and 8.9% (inter-day, n = 4). Finally, the proposed method was successfully applied for detecting 1-hydroxypyrene in urine samples from college students, smokers, gas station workers, and chip factory workers. The detected concentration in actual urine samples ranged from 0.46 to 5.26 µg/L. Taken together, this simple and cost-effective nylon needle filter-based solid-phase extraction device showed an excellent application potential for pretreating hydrophobic analytes from aqueous samples.

Determination of fipronil and its metabolites in environmental water samples by meltblown nonwoven fabric-based solid-phase extraction combined with gas chromatography-electron capture detection.

In this study, a new method for the determination of fipronil and its three metabolites in environmental water samples was developed based on meltblown nonwoven fabric solid-phase extraction combined with gas chromatography-electron capture detection. As the core material of medical masks, meltblown nonwoven fabric is made of polypropylene superfine fibers which are randomly distributed and bonded together with a relatively large specific surface area and good permeability. Polypropylene as a high molecular hydrocarbon-based polymer has the characteristics of good hydrophobicity and lipophilicity, which can be applied for the separation and enrichment of hydrophobic substances in food, environment, and biological samples. The meltblown nonwoven fabric is soft and can fill the solid-phase extraction cartridge tightly. This aspect also makes it suitable to be used as an ideal solid-phase extraction sorbent. A series of parameters influencing the extraction efficiency were investigated, and under the optimized conditions, fipronil and its three metabolites had a good linear relationship in the range of 0.2-100 µg/L with a correlation coefficient R2 of more than 0.999. The recoveries at three spiked concentrations were in the range of 99.2-107.3% with the relative standard deviations less than 9.8% (intra-day) and 8.1% (inter-day). The limit of detection for the four target analytes was in the range of 0.02-0.06 µg/L. Finally, this method was successfully applied in the analysis of fipronil and its three metabolites in various types of environmental water samples.

[Circular RNA in Diabetes and its Complications].

Circular RNA (circRNA) is a special group of non-coding RNA.Unlike linear RNA,circRNA is a closed circular structure formed by reverse splicing of pre-mRNA,with highly stable expression and wide distribution in eukaryotes.CircRNA has multiple functions by acting as microRNA sponges or binding with RNA-binding proteins.They can be used as biomarkers for many diseases.The latest research shows that circRNA plays a role in the pathogenesis of diabetes mellitus and the related chronic complications.In this review,we summarized the current progress and underlying mechanisms of circRNA in diabetes mellitus and the related complications.

[Mechanism of polyphyllin A in inhibition of proliferation and induction of apoptosis of gastric cancer cells by directly targeting ETS-1].

The present study investigated the mechanism of polyphyllin A(PPA) in inhibiting gastric cancer(GC) cells. GC cells(SGC7901 and MGC803 cell lines) were treated with PPA at different concentrations. The effect of PPA on the proliferation of GC cells was detected by MTT assay, real-time cell analysis(RTCA) assay, and clone-forming assay, respectively. Reactive oxygen species(ROS) of GC cells was detected by flow cytometry. The change of mitochondrial membrane potential was detected by JC-1 assay. The expression and phosphorylation levels of apoptosis-related proteins(caspase-9, caspase-3, and PARP) and proteins related to the signaling pathway(ETS-1, CIP2 A, and Akt) were detected by Western blot. The binding sites of PPA to ETS-1 were analyzed by molecular docking. The affinity of PPA and ETS-1 was detected by drug affinity responsive target stability(DARTS) assay. PPA had a significant inhibitory effect on the proliferation and colony formation of GC cells at a low concentration. The PPA groups showed increased ROS and decreased mitochondrial membrane potential. PPA down-regulated the precursor expression of caspase-9 and caspase-3 and promoted the cleavage of PARP, suggesting that PPA induced the apoptosis of GC cells through the mitochondrial pathway. PPA significantly reduced expression levels of CIP2 A and the phosphorylation of downstream Akt. Molecular docking showed that PPA bound to the ETS domain of ETS-1, the transcription factor of CIP2 A, and formed hydrogen bonds with Pro319 and Asp317. DARTS assay further confirmed that PPA significantly prevented the hydrolysis of ETS-1 by pronase, which was inductive of the direct binding effect of PPA and ETS-1. PPA inhibits the proliferation and induces the apoptosis of GC cells by directly targeting ETS-1 to down-regulate the ETS-1/CIP2 A/Akt signaling pathway.

[Mechanism of polyphyllin â targeting EGFR to affect proliferation and apoptosis of human breast cancer cells].

This study aims to investigate the molecular mechanism of polyphyllin Ⅰ(PPⅠ) inhibiting proliferation of human breast cancer cells. Human breast cancer BT474 and MDA-MB-436 cells were treated with different concentrations of PPⅠ, and then the effect of PPⅠ on cell proliferation was detected by MTT assay, trypan blue dye exclusion assay, real-time cell analysis, and clone forming assay, respectively. The apoptosis was detected by Annexin V-FITC/PI staining and then analyzed by flow cytometry. The change of mitochondrial membrane potential was detected by flow cytometry after fluorescent probe JC-1 staining. Western blot was used to detect protein expression and phosphorylation. Molecular docking was performed to detect the binding between PPⅠ and EGFR. The affinity between PPⅠ and EGFR was determined by drug affinity responsive target stability assay. The results indicated that PPⅠ inhibited the proliferation and colony formation of BT474 and MDA-MB-436 cells in a time-and concentration-dependent manner. The PPⅠ treatment group showed significantly increased apoptosis rate and significantly decreased mitochondrial membrane potential. PPⅠ down-regulated the expression of pro-caspase-3 protein, promoted the cleavage of PARP, and significantly reduced the phosphorylation levels of EGFR, Akt, and ERK. Molecular docking showed that PPⅠ bound to the extracellular domain of EGFR and formed hydrogen bond with Gln366 residue. Drug affinity responsive target stability assay confirmed that PPⅠ significantly prevented pronase from hydrolyzing EGFR, indicating that PPⅠ and EGFR have a direct binding effect. In conclusion, PPⅠ inhibited the proliferation and induced apoptosis of breast cancer cells by targeting EGFR to block its downstream signaling pathway. This study lays a foundation for the further development of PPⅠ-targeted drugs against breast cancer.

LncRNA MALAT1 aggravates oxygen-glucose deprivation/reoxygenation-induced neuronal endoplasmic reticulum stress and apoptosis via the miR-195a-5p/HMGA1 axis.

BACKGROUND: This study aimed to investigate the potential role and molecular mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in cerebral ischemia/reperfusion injury. RESULTS: Using an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model, we determined that the expression of MALAT1 was significantly increased during OGD/R. MALAT1 knockdown reversed OGD/R-induced apoptosis and ER stress. Mechanistically, MALAT1 promoted OGD/R-induced neuronal injury through sponging miR-195a-5p to upregulating high mobility group AT-hook1 (HMGA1). CONCLUSIONS: Collectively, these data demonstrate the mechanism underlying the invovlvement of MALAT1 in cerebral ischemia/reperfusion injury, thus providing translational evidence that MALAT1 may serve as a novel biomarker and therapeutic target for ischemic stroke.

Qingbo, a common cyprinid fish, responds diversely in behavior and locomotion to predators with different hunting modes.

Almost all prey live in habitats with predators with different hunting modes; however, most studies on predation have investigated the effects of only one predator at a time. In this study, we aimed to investigate whether qingbo (Spinibarbus sinensis), a common cyprinid fish, responds differently to active hunting and ambush predators and how qingbo responds when both types of predators coexist. Juvenile qingbo were subjected to catfish (Clarias fuscus, active hunter) exposure, snakehead fish (Channa argus, ambush hunter) exposure, or mixed predator exposure (catfish and snakehead coexistence) for a duration of 60 days. Then, their growth, behaviors, swimming performance, and metabolism were measured. Qingbo subjected to active hunting predator exposure exhibited decreased activity and predator inspection and improved fast-start escape performance compared to those in the control group. However, none of the parameters of the fish subjected to ambush predator exposure changed significantly. Fish subjected to mixed predator exposure exhibited improved fast-start escape performance but increased maintenance energy expenditure, whereas no changes were observed in any of the behavioral variables. Qingbo showed a stronger anti-predator response to active hunting predators than to ambush predators, suggesting that the fish exhibit a stronger anti-predator response to a current direct threat than to a potential threat (a predator exists nearby but seldom presents in attack behavior). Additionally, the response of prey fish to multiple predators was quite complex, and the coexistence and interaction of multiple predator species with different hunting modes may lead to serious stress responses and confound the prey's behavioral responses to each predator.

Identification and functional analysis of transforming growth factor-ß type III receptor (TßR3) from Scylla paramamosain: The first evidence of TßR3 involved in development and innate immunity in invertebrates.

Transforming growth factor-ß type III receptor (TßR3), as a co-receptor of TGF-ß superfamily, plays critical roles in development and growth as well as some disease pathogeneses by presenting ligands to other receptors in vertebrates. However, the identification and functional characterization of TßR3 had not been reported yet in invertebrates. In the present study, TßR3 was first identified and characterized in mud crab Scylla paramamosain. The obtained cDNA length of SpTßR3 was 2, 424 bp with a 1, 854 bp open reading frame, which encoded a putative peptide of 617 amino acids containing a typical transmembrane region and a Zona pellucida (ZP) domain. Real-time PCR results showed that SpTßR3 was predominantly expressed at early embryonic development stage and early postmolt stage, suggesting its participation in development and growth. We report, for the first time in invertebrates, the challenge of both Vibro alginolyticus and Poly (I:C) could alter the expression patterns of SpTßR3. Notably, the expression levels of SpIKK, two NF-κB members (SpRelish and SpDorsal), and five antimicrobial peptide genes (SpCrustin and SpALF1-4) were significantly suppressed when SpTßR3 was interfered in vivo. Secondly, the overexpression of SpTßR3 in vitro could activate NF-κB signaling through the dual-luciferase reporter assays. Furthermore, the bacterial clearance assay after SpTßR3 was silenced in vivo highlighted the potential of SpTßR3 in activating the innate immune responses. These results implied the involvement of SpTßR3 in the innate immune responses by regulating the NF-κB pathway. This study first indicated that TßR3 was present in invertebrate, and it participated in not only the development and growth but also the innate immunity of S. paramamosain. It also provided new insights into the origin or evolution of TGF-ß receptors in crustacean species and even in invertebrates.

Synthesis and characterization of luminescent SiO2 @Eu(phen-Si) core-shell nanospheres.

Four core-shell structured nanometre luminescent composites with different kernel sizes and different shell layer thicknesses (SiO2(500) @Eu (phen-Si)(50) , SiO2(500) @Eu (phen-Si)(15) , SiO2(250) @Eu (phen-Si)(5) and SiO2(250) @Eu (phen-Si)(10) ) were made by changing synthesis conditions. Here, initial subscript numbers in parentheses refer to the particle size of the SiO2 core, whereas the final subscript numbers in parentheses refer to shell layer thickness. In these composites, silica spheres of 500 nm or 250 nm were identified as the core. The shell layer was composited of silicon, 1,10-phenanthroline and europium perchlorate, abbreviated as Eu(phen-Si); the chemical formula of phen-Si was phen-N-(CONH (CH2 )Si(OCH2 CH3 )3 )2 . The composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and infrared spectroscopy. The monodispersed spherical SiO2 showed characteristics of a regular microstructure and a smooth surface, as well as the advantage of dispersity, shown by SEM. The Eu(phen-Si) complex was able to self-assemble into monodispersed SiO2 spheres, as seen using TEM. Fluorescence spectra indicated that the four composites had excellent luminescence properties. Furthermore, composites composed of a SiO2 core and a 250 nm kernel size exhibited stronger fluorescence than 500 nm kernel-sized composites. Fluorescence properties were affected by shell thickness: the thicker the shell, the greater the fluorescence intensity. For the four composites, quantum yield values and fluorescence lifetime corresponded to fluorescence emission intensity data as quantum yield values and fluorescence lifetime were higher, and luminescence properties increased.

Boosting to Amplify Signal with Isobaric Labeling (BASIL) Strategy for Comprehensive Quantitative Phosphoproteomic Characterization of Small Populations of Cells.

Comprehensive phosphoproteomic analysis of small populations of cells remains a daunting task due primarily to the insufficient MS signal intensity from low concentrations of enriched phosphopeptides. Isobaric labeling has a unique multiplexing feature where the "total" peptide signal from all channels (or samples) triggers MS/MS fragmentation for peptide identification, while the reporter ions provide quantitative information. In light of this feature, we tested the concept of using a "boosting" sample (e.g., a biological sample mimicking the study samples but available in a much larger quantity) in multiplexed analysis to enable sensitive and comprehensive quantitative phosphoproteomic measurements with <100 000 cells. This simple boosting to amplify signal with isobaric labeling (BASIL) strategy increased the overall number of quantifiable phosphorylation sites more than 4-fold. Good reproducibility in quantification was demonstrated with a median CV of 15.3% and Pearson correlation coefficient of 0.95 from biological replicates. A proof-of-concept experiment demonstrated the ability of BASIL to distinguish acute myeloid leukemia cells based on the phosphoproteome data. Moreover, in a pilot application, this strategy enabled quantitative analysis of over 20 000 phosphorylation sites from human pancreatic islets treated with interleukin-1ß and interferon-γ. Together, this signal boosting strategy provides an attractive solution for comprehensive and quantitative phosphoproteome profiling of relatively small populations of cells where traditional phosphoproteomic workflows lack sufficient sensitivity.

Carrier-Assisted Single-Tube Processing Approach for Targeted Proteomics Analysis of Low Numbers of Mammalian Cells.

Heterogeneity in composition is inherent in all cell populations, even those containing a single cell type. Single-cell proteomics characterization of cell heterogeneity is currently achieved by antibody-based technologies, which are limited by the availability of high-quality antibodies. Herein we report a simple, easily implemented, mass spectrometry (MS)-based targeted proteomics approach, termed cLC-SRM (carrier-assisted liquid chromatography coupled to selected reaction monitoring), for reliable multiplexed quantification of proteins in low numbers of mammalian cells. We combine a new single-tube digestion protocol to process low numbers of cells with minimal loss together with sensitive LC-SRM for protein quantification. This single-tube protocol builds upon trifluoroethanol digestion and further minimizes sample losses by tube pretreatment and the addition of carrier proteins. We also optimized the denaturing temperature and trypsin concentration to significantly improve digestion efficiency. cLC-SRM was demonstrated to have sufficient sensitivity for reproducible detection of most epidermal growth factor receptor (EGFR) pathway proteins expressed at levels ≥30 000 and ≥3000 copies per cell for 10 and 100 mammalian cells, respectively. Thus, cLC-SRM enables reliable quantification of low to moderately abundant proteins in less than 100 cells and could be broadly useful for multiplexed quantification of important proteins in small subpopulations of cells or in size-limited clinical samples. Further improvements of this method could eventually enable targeted single-cell proteomics when combined with either SRM or other emerging ultrasensitive MS detection.

A separation voltage polarity switching method for higher sample loading capacity and better separation resolution in transient capillary isotachophoresis separation.

A separation voltage polarity switching transient capillary isotachophoresis (PS-tCITP) was developed to overcome a major sample loading volume limitation in transient capillary isotachophoresis (tCITP). The fundamental idea of PS-tCITP is to let sample ions move back and forth in a separation capillary during their initial isotachophoresis focusing stage by switching the polarity of the separation voltage, in order to both increase the sample loading volume and improve the separation efficiency as compared to the conventional tCITP method. The experimental evaluation of the novel PS-tCITP method by using two peptide standards at 2 µM concentration showed that the maximum sample loading volume could be increased from 45% of the total separation capillary volume in tCITP to 70% in PS-tCITP, which resulted in a more than 1.5 fold increase in the peptide peak intensity at a given length/volume of the separation capillary. Due to the consecutive focusing of sample volume from each polarity switching of the separation voltage, the separation time window at a given sample loading volume was also increased significantly in PS-tCITP as compared to tCITP. Experiment comparison between tCITP and PS-tCITP at 45% sample loading volume using the same setup showed that the migration time difference between the two peptide peaks increased from 0.3 min in tCITP to 0.363 min in PS-tCITP with similar peak widths and heights, resulting in roughly a 21% improvement in separation resolution. The performance advantages of PS-tCITP separation over tCITP separation were further verified by using a mixture of six peptide standards.

Transforming growth factor-ß-activating kinase 1 and its binding protein 1 participate in the innate immune responses via modulating the IMDNFκB signaling in mud crab (Scylla paramamosain).

Transforming growth factor-ß-activating kinase 1 (TAK1) is essential for diverse important biological functions, such as innate immunity, development and cell survival. In the present study, the homologs of TAK1 and TAK1-binding protein 1 (TAB1) were identified and characterized from mud crab Scylla paramamosain for the first time. The full-length cDNAs of SpTAK1 and SpTAB1 were 2, 226 bp and 2, 433 bp with 1, 782 bp and 1, 533 bp open reading frame (ORF), respectively. The deduced SpTAK1 protein contained a conserved S_TKc (Serine/threonine protein kinases, catalytic) domain, and the putative SpTAB1 protein possessed a typical PP2Cc (Serine/threonine phosphatases, family 2C, catalytic) domain and a potential TAK1 docking motif. Real-time PCR analysis showed that SpTAK1 and SpTAB1 were highly expressed at early development stages, suggesting their participation in crab's development process. Moreover, the expression levels of SpTAK1 and SpTAB1 in hepatopancreas were positively stimulated after challenge with Vibro alginolyticus and Poly (I:C), implying the involvement of SpTAK1 and SpTAB1 in innate immune responses against both bacterial and viral infections. When SpTAK1 or SpTAB1 were silenced in vivo, the expression levels of two IMDNFκB signaling components (SpIKKß and SpRelish) and six antimicrobial peptide (AMP) genes (SpALF1-5 and SpCrustin) were significantly reduced, and the bacteria clearance capacity of crabs was also markedly impaired in SpTAK1 or SpTAB1 silenced crabs. Additionally, overexpression of SpTAK1 and SpTAB1 in HEK293T cells could markedly activate the mammalian NF-κB signaling. Collectively, our results suggested that TAK1 and TAB1 regulated crab's innate immunity via modulating the IMDNFκB signaling. These findings may provide new insights into the TAK1/TAB1-mediated signaling cascades in crustaceans and pave the way for a better understanding of crustacean innate immune system.

Biotransformation of Huperzine B by a Fungal Endophyte of Huperzia serrata.

The biotransformation of huperzine B (hupB), one of the characteristic bioactive constituents of the medicinal plant Huperzia serrata, by a fungal endophyte of the host plant was studied. One new compound, 8α,15α-epoxyhuperzine B (1), along with two known oxygenated hupB analogs, 16-hydroxyhuperzine B (2) and carinatumin B (3), was isolated and identified. The structures of all the isolates were deduced by spectroscopic methods including NMR, MS, IR, and UV spectra. The known compounds 2 and 3 were obtained from a microbial source for the first time. To the best of our knowledge, it is the first report on the microbial transformation of hupB and would facilitate further structural modification of hupB by chemo-enzymatic method. In the LPS-induced neuro-inflammation injury assay, 8α,15α-epoxyhuperzine B (1) exhibited moderate neuroprotective activity by increasing the viability of U251 cell lines with an EC50 of 40.1 nm.

Targeted Quantification of Phosphorylation Dynamics in the Context of EGFR-MAPK Pathway.

Large-scale phosphoproteomics with coverage of over 10,000 sites of phosphorylation have now been routinely achieved with advanced mass spectrometry (MS)-based workflows. However, accurate targeted MS-based quantification of phosphorylation dynamics, an important direction for gaining quantitative understanding of signaling pathways or networks, has been much less investigated. Herein, we report an assessment of the targeted workflow in the context of signal transduction pathways, using the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway as our model. A total of 43 phosphopeptides from the EGFR-MAPK pathway were selected for the study. The recovery and sensitivity of two commonly used enrichment methods, immobilized metal affinity chromatography (IMAC) and titanium oxide (TiO2), combined with selected reaction monitoring (SRM)-MS were evaluated. The recovery of phosphopeptides by IMAC and TiO2 enrichment was quantified to be 38 ± 5% and 58 ± 20%, respectively, based on internal standards. Moreover, both enrichment methods provided comparable sensitivity from 1 to 100 µg starting peptides. Robust quantification was consistently achieved for most targeted phosphopeptides when starting with 25-100 µg peptides. However, the numbers of quantified targets significantly dropped when peptide samples were in the 1-25 µg range. Finally, IMAC-SRM was applied to quantify signaling dynamics of EGFR-MAPK pathway in Hs578T cells following 10 ng/mL EGF treatment. The kinetics of phosphorylation clearly revealed early and late phases of phosphorylation, even for very low abundance proteins. These results demonstrate the feasibility of robust targeted quantification of phosphorylation dynamics for specific pathways, even starting with relatively small amounts of protein.

Effects of both cold and heat stress on the liver of the giant spiny frog (Quasipaa spinosa): stress response and histological changes.

Ambient temperature-associated stress can affect normal physiological functions in ectotherms. To assess the effects of cold or heat stress on amphibians, giant spiny frogs (Quasipaa spinosa) were acclimated at 22°C followed by exposure to 5°C or 30°C for 0, 3, 6, 12, 24 and 48 h, respectively. Histological alterations, apoptotic index, generation of mitochondrial reactive oxygen species (ROS), antioxidant activity indices and stress-response gene expression in frog livers were subsequently determined. Results showed that many fat droplets appeared after 12 h of heat stress and the percentage of melanomacrophage centres significantly changed after 48 h at both stress conditions. Furthermore, the mitochondrial ROS levels were elevated in a time-dependent manner up to 6 h and 12 h in the cold and heat stress groups, respectively. The activities of superoxide dismutase, glutathione peroxidase and catalase were successively increased with increasing periods of cold or heat exposure, and their gene expression levels showed similar changes in both stress conditions. Most tested heat shock protein (HSP) genes were sensitive to temperature exposure, and the expression profiles of most apoptosis-related genes was significantly upregulated at 3 and 48 h under cold and heat stress, respectively. Apoptotic index at 48 h under cold stress was significantly higher than that under heat stress. Notably, lipid droplets, HSP30, HSP70 and HSP110 might be suitable bioindicators of heat stress. The results of these alterations at physiological, biochemical and molecular levels might contribute to a better understanding of the stress response of Q. spinosa, and perhaps amphibians more generally, under thermal stress.

Quantity discrimination in fish species: fish use non-numerical continuous quantity traits to select shoals.

Fish typically prefer to live in big shoals due to the associated ecological benefits. Shoaling is a behavior that depends on the ability to quantitatively discriminate. The fundamental mechanism involved in quantity discrimination determines whether fish can discriminate a shoal using numerical discrete cues (e.g., number of shoal members), non-numerical continuous traits (e.g., total body surface area) or both; however, the mechanism is currently a controversial topic. In the present study, we used a spontaneous choice experiment to test whether guppy (Poecilia reticulata), zebrafish (Danio rerio), Chinese crucian carp (Carassius auratus) and qingbo (Spinibarbus sinensis) rely on continuous (i.e., body surface area) or discrete (i.e., number of shoal members) information for shoal selection by altering the body surface area (cumulative body surface area ratio of 3:2 or 1:1) between two stimulus shoals with a different number of members (2 individuals vs 3 individuals). All four fish species preferred to shoal with the stimulus shoal with the larger cumulative surface area even if the shoal had fewer members; however, fish showed no shoal preference when the cumulative surface body areas of both stimulus shoals were equal. Furthermore, qingbo did not numerically discriminate between a shoal with 1 individual and a shoal with 3 individuals when the cumulative surface areas of both stimulus shoals were equal; however, qingbo showed a preference for the shoal with the larger cumulative surface area when the two stimulus shoals each had 3 individuals. In conclusion, the present study demonstrated that all four fish species relied only on non-numerical continuous quantity information for shoal selection, at least under a difficult task (i.e., 2 vs 3).