Role of cancer stem cell ecosystem on breast cancer metastasis and related mouse models

Breast cancer metastasis is responsible for most breast cancer-related deaths and is influenced by many factors within the tumor ecosystem,including tumor cells and microenvironment.Breast cancer stem cells(BCSCs)constitute a small population of cancer cells with unique characteristics,including their capacity for self-renewal and differentiation.Studies have shown that BCSCs not only drive tumorigenesis but also play a crucial role in promoting metastasis in breast cancer.The tumor microenvironment(TME),composed of stromal cells,immune cells,blood vessel cells,fibroblasts,and microbes in proximity to cancer cells,is increasingly recognized for its crosstalk with BCSCs and role in BCSC survival,growth,and dissemination,thereby influencing metastatic ability.Hence,a thorough understanding of BCSCs and the TME is critical for unraveling the mechanisms underlying breast cancer metastasis.In this review,we summarize current knowledge on the roles of BCSCs and the TME in breast cancer metastasis,as well as the underlying regulatory mechanisms.Furthermore,we provide an overview of relevant mouse models used to study breast cancer metastasis,as well as treatment strategies and clinical trials addressing BCSC-TME interactions during metastasis.Overall,this study provides valuable insights for the development of effective therapeutic strategies to reduce breast cancer metastasis.

Mouse KL2 is a unique MTSE involved in chromosome-based spindle organization and regulated by multiple kinases during female meiosis

Microtubule-severing enzymes(MTSEs)play important roles in mitosis and meiosis of the primitive organisms.However,their roles in mammalian female meiosis,which accounts for over 80%of gamete-originated human reproductive diseases,remain unexplored.In the current study,we reported that katanin-like 2(KL2)was the only MTSE concentrating at chromosomes.Furthermore,the knockdown of KL2 significantly reduced the chromosome-based increase in the microtubule(MT)polymer,increased aberrant kinetochore-MT(K-MT)attachment,delayed meiosis,and severely affected normal fertility.We demonstrated that the inhibition of aurora B,a key kinase for correcting aberrant K-MT attachment,significantly eliminated KL2 expression from chromosomes.Additionally,KL2 interacted with phosphorylated eukaryotic elongation factor-2 kinase,and they competed for chromosome binding.Phosphorylated KL2 was also localized at spindle poles,with its phosphorylation regulated by extracellular signal-regulated kinase 1/2.In summary,the current study reveals a novel function of MTSEs in mammalian female meiosis and demonstrates that multiple kinases coordinate to regulate the levels of KL2 at chromosomes.

Comparison of immune responses and intestinal flora in epicutaneously sensitized BALB/c or C57BL/6 mouse models of food allergy

Cutaneous exposure to food allergens through a disrupted skin barrier is recognized as an important cause of food allergy,and the cutaneous sensitized mouse model has been established to investigate relevant allergic disorders.However,the role of different genetic backgrounds of mice on immune responses to food allergens upon epicutaneous sensitization is largely unknown.In this study,two strains of mice,i.e.,the BALB/c and C57BL/6 mice,were epicutaneously sensitized with ovalbumin on atopic dermatitis(AD)-like skin lesions,followed by intragastric challenge to induce IgE-mediated food allergy.Allergic outcomes were measured as clinical signs,specific antibodies and cytokines,and immune cell subpopulations,as well as changes in intestinal barrier function and gut microbiota.Results showed that both strains of mice exhibited typical food-allergic symptoms with a Th2-skewed response.The C57BL/6 mice,rather than the BALB/c mice,were fitter for establishing an epicutaneously sensitized model of food allergy since a stronger Th2-biased response and severer disruptions in the intestinal barrier and gut homeostasis were observed.This study provides knowledge for selecting an appropriate mouse model to study food-allergic responses associated with AD-like skin lesions and highlights the role of genetic variations in the immune mechanism underlying pathogenesis of food allergy.

Effects of Polygala fallax Hemsl Water Extract on a Mouse Model of Gastric Motility Disorders

[Objectives]To explore the effects of Polygona fallax Hemsl water extract on gastrointestinal motility in normal mice and gastric motility disorder model mice and approximate mechanism.[Methods]Using normal mice and mice with gastric motility disorders(modeled with atropine),the effects of different mass concentration groups of P.fallax Hemsl water extract(0.125,0.250,0.500 g/mL)and domperidone groups on gastric residual rate,small intestine propulsion rate,serum motilin(MLT),vasoactive intestinal peptide(VIP),and tissue morphology were studied.[Results]There was a highly significant difference(P<0.01)in the small intestine propulsion rate of liquid in normal mice among the different concentration groups of P.fallax Hemsl water extract compared to the blank group.The small intestine propulsion rate and gastric residue rate of semi-solid paste were statistically significant compared to the blank group(P<0.05).Among them,there was a highly significant difference between the high concentration group(67.75%±7.65%,46.5%±10.62%)and the medium concentration group(60.90%±5.87%,59.27%±7.82%)(P<0.01).There was statistical significance in normal mouse serum MLT content in the high concentration group(P<0.05).There was no effect on serum VIP levels in normal mice;no effect on the morphology of stomach and intestinal tissues of normal mice.The small intestine propulsion rate and gastric residue rate of liquid and semi-solid paste in mice with gastric motility disorders were statistically significant compared to the atropine group,with extremely significant differences(P<0.01).[Conclusions]P.fallax Hemsl water extract has a promoting effect on gastrointestinal motility.One of the specific mechanisms by which P.fallax Hemsl promotes gastrointestinal motility in normal mice may be related to the content of MLT in mouse serum.The mechanism of action in atropine induced gastric paresis mice may be related to the reactivation of M receptors,and the action mechanism of P.fallax Hemsl does not change the original histological basis.It can be inferred that P.fallax Hemsl water extract has a synergistic effect on promoting gastrointestinal motility through other mechanisms,but it is not fully understood and further in-depth research is needed.

Establishment and Evaluation of a Mouse Model of Allergic Rhinitis

[Objectives]To explore a new method for induction of allergic rhinitis in mice,and compare and evaluate it with common modeling methods.[Methods]36 mice were randomly divided into the control group,blank group and experimental group,and there were 12 mice in each group.The mice in the control group were conventionally induced.That is,the mice were first injected intraperitoneally with the mixture composed of OVA 50μg,[Al(OH)3]5 mg and 1ml of normal saline once every other day,and then since the 15 th d,20μL of 5%OVA solution was dropped into each nasal cavity once a day,which lasted for 7 d.The blank group was treated with the same amount of normal saline according to the control group,and received intraperitoneal injection and bilateral nasal drip respectively.In the experimental group,mice were first given intraperitoneal injection of the mixture composed of ovalbumin(OVA)75μg,aluminum hydroxide gel[Al(OH)3]8 mg and normal saline 1.5 mL for basic sensitization.On the 26 th d,20μL of 3%OVA solution was dropped into each nasal cavity once a day,which lasted for 10 d.The number of sneezes,the number of nose scratching,the amount of nasal discharge,and the activity of mice in each group were observed,and the behavior of allergic reaction was scored.Meanwhile,the number of eosinophils in the nasal discharge of mice and the IgE content in serum were measured.[Results]The score of nasal stimulation symptoms,the number of eosinophils and serum IgE level of mice in the control group and the experimental group were higher than those in the blank group(P<0.05),and there was no statistical significance between the two groups in the three indicators(P>0.05).[Conclusions]The modeling method was more suitable for the development of allergic rhinitis patients condition,and reduced the probability of death of mice due to modeling,and simplified the experimental operation.

Expression levels of K_(ATP)channel subunits and morphological changes in the mouse liver after exposure to radiation

BACKGROUND ATP sensitive K+(K_(ATP))channels are ubiquitously distributed in various of cells and tissues,including the liver.They play a role in the pathogenesis of myocardial and liver ischemia.AIM To evaluate the radiation-induced changes in the expression of K_(ATP)channel subunits in the mouse liver to understand the potential role of K_(ATP)channels in radiation injury.METHODS Adult C57BL/6 mice were randomly exposed toγ-rays at 0 Gy(control,n=2),0.2 Gy(n=6),1 Gy(n=6),or 5 Gy(n=6).The livers were removed 3 and 24 h after radiation exposure.Hematoxylin and eosin staining was used for morphological observation;immunohistochemical staining was applied to determine the expression of K_(ATP)channel subunits in the liver tissue.RESULTS Compared with the control group,the livers exposed to 0.2 Gyγ-ray showed an initial increase in the expression of Kir6.1 at 3 h,followed by recovery at 24 h after exposure.Exposure to a high dose of 5.0 Gy resulted in decreased expression of Kir6.1 and increased expression of SUR2B at 24 h.However,the expression of Kir6.2,SUR1,or SUR2A had no remarkable changes at 3 and 24 h after exposure to any of these doses.CONCLUSION The expression levels of Kir6.1 and SUR2B in mouse liver changed differently in response to different radiation doses,suggesting a potential role for them in radiation-induced liver injury.

Mouse models of epithelial ovarian cancer for preclinical studies

Epithelial ovarian cancer(EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefore, exploration of relevant preclinical animal models that consider the heterogenic nature of EOC is of great importance for the development of novel therapeutic strategies that can be translated clinically to combat this devastating disease. In this review, we discuss recent progress in the development of preclinical mouse models for EOC study as well as their advantages and limitations.

MicroRNAs in mouse and rat models of experimental epilepsy and potential therapeutic targets

Epilepsy is a common and serious neurological disease that causes recurrent seizures. The brain damage caused by seizures can lead to depression, anxiety, cognitive impairment, or disability. In almost all cases chronic seizures are difficult to cure. MicroRNAs are widely expressed in the central nervous system and play important roles in the pathogenesis of several neurological disorders, including epilepsy. A variety of animals(mostly mice and rats) have been used to induce experimental epilepsy using different protocols and miRNA profiling performed. Most of the recent studies reviewed had performed miRNA profiling in hippocampal tissues and a large number of microRNAs were dysregulated when compared to controls. Most notably, miR-132-3p,-146a-5p,-10a-5p,-21a-3p,-27a-3p,-142a-5p,-212-3p,-431-5p, and-155 were upregulated in both the mouse and rat studies. Overexpression of miR-137 and miR-219 decreased seizure severity in a mouse epileptic model, and suppression of miR-451,-10a-5p,-21a-5p,-27a-5p,-142a-5p,-431-5p,-155, and-134 had a positive influence on seizure behavior. In the rat studies, overexpression of miR-139-5p decreased neuronal damage in drug-resistant rats and inhibition of miR-129-2-3p,-27a-3p,-155,-134,-181a, and-146a had a positive effect on seizure behavior and/or reduced the loss of neuronal cells. Further studies are warranted using adult female and immature male and female animals. It would also be helpful to test the ability of specific agomirs and antagomirs to control seizure activity in a subhuman primate model of epilepsy such as adult marmosets injected intraperitoneally with pilocarpine or cynomolgus monkeys given intrahippocampal injections of kainic acid.

Anti-infection effects of heparin on SARS-CoV-2 in a diabetic mouse model

Severe acute respiratory syndrome coronavirus 2(SARSCo V-2)infection can result in more severe syndromes and poorer outcomes in patients with diabetes and obesity.However,the precise mechanisms responsible for the combined impact of coronavirus disease 2019(COVID-19)and diabetes have not yet been elucidated,and effective treatment options for SARS-Co V-2-infected diabetic patients remain limited.To investigate the disease pathogenesis,K18-h ACE2 transgenic(h ACE2^(Tg))mice with a leptin receptor deficiency(h ACE2-Lepr^(-/-))and high-fat diet(h ACE2-HFD)background were generated.The two mouse models were intranasally infected with a 5×10^(5) median tissue culture infectious dose(TCID_(50))of SARSCo V-2,with serum and lung tissue samples collected at 3days post-infection.The h ACE2-Lepr^(-/-)mice were then administered a combination of low-molecular-weight heparin(LMWH)(1 mg/kg or 5 mg/kg)and insulin via subcutaneous injection prior to intranasal infection with1×10^(4) TCID_(50)of SARS-Co V-2.Daily drug administration continued until the euthanasia of the mice.Analyses of viral RNA loads,histopathological changes in lung tissue,and inflammation factors were conducted.Results demonstrated similar SARS-Co V-2 susceptibility in h ACE2^(Tg)mice under both lean(chow diet)and obese(HFD)conditions.However,compared to the h ACE2-Lepr^(+/+)mice,h ACE2-Lepr^(-/-)mice exhibited more severe lung injury,enhanced expression of inflammatory cytokines and hypoxia-inducible factor-1α(HIF-1α),and increased apoptosis.Moreover,combined LMWH and insulin treatment effectively reduced disease progression and severity,attenuated lung pathological changes,and mitigated inflammatory responses.In conclusion,preexisting diabetes can lead to more severe lung damage upon SARS-Co V-2 infection,and LMWH may be a valuable therapeutic approach for managing COVID-19patients with diabetes.

Designing and generating a mouse model:frequently asked questions

Genetically engineered mouse(GEM)models are commonly used in biomedical research.Generating GEMs involve complex set of experimental procedures requiring sophisticated equipment and highly skilled technical staff.Because of these reasons,most research institutes set up centralized core facilities where custom GEMs are created for research groups.Researchers,on the other hand,when they begin thinking about generating GEMs for their research,several questions arise in their minds.For example,what type of model(s)would be best useful for my research,how do I design them,what are the latest technologies and tools available for developing my model(s),and finally how to breed GEMs in my research.As there are several considerations and options in mouse designs,and as it is an expensive and time-consuming endeavor,careful planning upfront can ensure the highest chance of success.In this article,we provide brief answers to several frequently asked questions that arise when researchers begin thinking about generating mouse model(s)for their work.

Morphological comparison and gonadotropins cell localization of mature female turbot and mouse pituitary

Reproduction is subtlety regulated by the hypothalamic-pituitary-gonad(HPG)axis in vertebrates.Pituitary gland is the center of the HPG axis,while pituitary gonadotropins follicle stimulating hormone(FSH)and luteinizing hormone(LH)were identified the key elements of the HPG axis in teleost and mammal.Morphology,cell lines,and gonadotropins cell localization of female turbot and mouse pituitary were determined at mature stage to illustrate the anatomical difference and cell characteristics in this study.Results show that turbot pituitary is chicken heart-shaped,dorsoventral,located on the ventral surface of the diencephalon.The mouse pituitary is oval,located in the pituitary fossa of the sella turcica at the skull base.Two well-distinguished areas adenohypophysis(AH)and neurohypophysis(NH)in pituitary were identified in turbot and mouse.Turbot AH comprised the rostral pars distalis(RPD),proximal pars distalis(PPD),and pars intermedia(PI).NH was not pronounced and with finger-like protrusions into PPD.However,mouse AH only comprised the pars distalis(PD)and PI.NH distribution was semicircular.Three main types of cells(acidophilic,basophilic,and chromophobic cells)were distributed in the mouse PD region,whereas appeared in the turbot PPD,RPD,and PI.Moreover,the percentage of mouse chromophobic and basophilic cells was higher and lower than that of turbot,respectively.The diameter of the aforementioned three cells in the mouse was significantly higher than turbot.fshβ-and lhβ-immunoreactive signals were identified in turbot-distinct pituitary cells that primarily occupied the peripheral and central regions of AH.However,mouse fsh-and lh-immunoreactive cells were expressed in the same cells and present in the PD.These results demonstrate the significantly difference of pituitary morphology,cell lines and gonadotropins(fshβand lhβ)location in female turbot and mouse.These differences help for fully understand the evolution and endocrinological functions of pituitary.

Lycium ruthenicum Murr. treatment attenuates APP_(SWE)/PS1ΔE9 mouse model-like mitochondrial dysfunction in Slc25a46 knockout mouse model

Mitochondrial dysfunction is proposed to be substantially associated with ageing and ageing-related diseases like Alzheimer's disease(AD). However, it is unclear whether different mouse models with mitochondrialrelated diseases have similar changes in mitochondrial morphology of the same tissues. Moreover, whether similarities in mitochondrial morphology can be a suitable marker for screening and/or discovering mitochondrial-protective substances remains unknown. Mitochondria morphology in different tissues of a novel mitochondrial outer membrane protein Slc25a46 knockout mouse and a traditional APP_(SWE)/PS1ΔE9 transgenic mouse were examined using transmission electron microscope(TEM). Both young Slc25a46 knockout mice and aged APP_(SWE)/PS1ΔE9 mice models showed similar mitochondrial damage in cerebellum tissues. The results indicated that different mitochondrial-related diseases shared similar alteration and defects in mitochondrial morphology. Furthermore, Lycium ruthenicum Murr. extract, a bioactive food substance with cognition-improving property, could effectively improve muscle strength and increase body weight in the Slc25a46 knockout mice. These findings suggest that mitochondrial morphology defects in mice models, particularly in the mitochondrial compartment, represent a unified and effective marker for screening and validating natural product-derived functional substances with mitochondrial protective properties. It also holds potential application in mitochondrial-impaired senile neurodegenerative diseases, especially in AD.

Mammalian Ste20-like kinase 1 inhibition as a cellular mediator of anoikis in mouse bone marrow mesenchymal stem cells

BACKGROUND The low survival rate of mesenchymal stem cells(MSCs)caused by anoikis,a form of apoptosis,limits the therapeutic efficacy of MSCs.As a proapoptotic molecule,mammalian Ste20-like kinase 1(Mst1)can increase the production of reactive oxygen species(ROS),thereby promoting anoikis.Recently,we found that Mst1 inhibition could protect mouse bone marrow MSCs(mBMSCs)from H 2 O 2-induced cell apoptosis by inducing autophagy and reducing ROS production.However,the influence of Mst1 inhibition on anoikis in mBMSCs remains unclear.AIM To investigate the mechanisms by which Mst1 inhibition acts on anoikis in isolated mBMSCs.METHODS Poly-2-hydroxyethyl methacrylate-induced anoikis was used following the silencing of Mst1 expression by short hairpin RNA(shRNA)adenovirus transfection.Integrin(ITGs)were tested by flow cytometry.Autophagy and ITGα5β1 were inhibited using 3-methyladenine and small interfering RNA,respe-ctively.The alterations in anoikis were measured by Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling and anoikis assays.The levels of the anoikis-related proteins ITGα5,ITGβ1,and phospho-focal adhesion kinase and the activation of caspase 3 and the autophagy-related proteins microtubules associated protein 1 light chain 3 II/I,Beclin1 and p62 were detected by Western blotting.RESULTS In isolated mBMSCs,Mst1 expression was upregulated,and Mst1 inhibition significantly reduced cell apoptosis,induced autophagy and decreased ROS levels.Mechanistically,we found that Mst1 inhibition could upregulate ITGα5 and ITGβ1 expression but not ITGα4,ITGαv,or ITGβ3 expression.Moreover,autophagy induced by upregulated ITGα5β1 expression following Mst1 inhibition played an essential role in the protective efficacy of Mst1 inhibition in averting anoikis.CONCLUSION Mst1 inhibition ameliorated autophagy formation,increased ITGα5β1 expression,and decreased the excessive production of ROS,thereby reducing cell apoptosis in isolated mBMSCs.Based on these results,Mst1 inhibition may provide a promising strategy to overcome anoikis of implanted MSCs.

Cat and Mouse Optimizer with Artificial Intelligence Enabled Biomedical Data Classification

Biomedical data classification has become a hot research topic in recent years,thanks to the latest technological advancements made in healthcare.Biome-dical data is usually examined by physicians for decision making process in patient treatment.Since manual diagnosis is a tedious and time consuming task,numerous automated models,using Artificial Intelligence(AI)techniques,have been presented so far.With this motivation,the current research work presents a novel Biomedical Data Classification using Cat and Mouse Based Optimizer with AI(BDC-CMBOAI)technique.The aim of the proposed BDC-CMBOAI technique is to determine the occurrence of diseases using biomedical data.Besides,the proposed BDC-CMBOAI technique involves the design of Cat and Mouse Optimizer-based Feature Selection(CMBO-FS)technique to derive a useful subset of features.In addition,Ridge Regression(RR)model is also utilized as a classifier to identify the existence of disease.The novelty of the current work is its designing of CMBO-FS model for data classification.Moreover,CMBO-FS technique is used to get rid of unwanted features and boosts the classification accuracy.The results of the experimental analysis accomplished by BDC-CMBOAI technique on benchmark medical dataset established the supremacy of the proposed technique under different evaluation measures.

Effect of Weak Noise on the Frequency Tuning of Mouse Inferior Collicular Neurons

In order to study the effect of weak noise on the sound signal extraction of mouse (Mus musculus Km) inferior collicular (IC) neurons from environments,we examined the changes in frequency tuning curves (FTCs) of 32 neurons induced by a weak noise relative to 5 dB below minimum threshold of tone (reMT-5 dB) under free field stimulation conditions.The results were as follows:① There were three types of variations in FTCs,sharpened (34.4%),broadened (18.8%),and unaffected (46.9%),nevertheless,only the alteration of sharpened FTCs was statistically different.② Sharpness of frequency tuning induced by a reMT-5 dB noise was very strong.Q 10 and Q 30 of FTCs were increased by (34.42±17.04)% (P=0.026,n=11) and (46.34±22.88)% (P=0.009,n=7).③ The changes of inverse-slopes (ISs,kHz/dB) between high (IS high) and low (IS low) limbs of FTCs were dissymmetry.The IS high of FTCs decreased markedly (P=0.046,n=7),however,there was little change (P=0.947,n=7) in IS low.Our data revealed for the first time that the weak noise could sharpen frequency tuning and increase the sensitivity on the high frequency of sound signal in IC neurons of mouse.

脊柱测量尺和Spinal Mouse脊柱测量仪测量胸椎后凸角、腰椎前凸角的信度和效度

目的:探讨脊柱测量尺和Spinal Mouse脊柱测量仪在测量胸椎后凸角、腰椎前凸角两个指标中的信度和效度。方法:随机筛选29名高中生作为受试对象,其中14名男生,15名女生。使用侧位全脊柱X线片作为胸椎后凸角和腰椎前凸角测试的金标准,分别使用Spinal Mouse脊柱测量仪、脊柱测量尺(Flexible ruler)对胸椎后凸角和腰椎前凸角进行测量。检验Spinal Mouse脊柱测量仪和脊柱测量尺测量脊柱矢状面角度的效度与信度,并检验两种仪器的重测信度。结果:Spinal Mouse脊柱测量仪测量的胸椎后凸角与X线片一致性最高,ICC为0.803(0.622,0.902),脊柱测量尺测量的胸椎后凸角ICC值为0.753(0.538,0.876);脊柱测量尺和Spinal Mouse脊柱测量仪测量的腰椎前凸角与X线片的测量结果相比,ICC值均低于0.4,一致性不高。在重复测量分析方面,使用Spinal Mouse脊柱测量仪和脊柱测量尺测量胸椎后凸角的ICC均高于0.8,使用Spinal Mouse测量腰椎前凸角的ICC为0.809(0.633,0.906),而使用脊柱测量尺测量腰椎前凸角的ICC为0.704(0.459,0.849)。结论:Spinal Mouse脊柱测量仪和脊柱测量尺在测试胸椎后凸角和腰椎前凸角中均具备良好的重测信度。与X线片对比,Spinal Mouse脊柱测量仪和脊柱测量尺测量胸椎后凸角具备一定的效度,可以在一定程度上替代X线片作为测量方法,且Spinal Mouse脊柱测量仪优于脊柱测量尺。但两种测试方法测量腰椎前凸角效度不佳。

Misère规则下Mouse游戏的最优策略

研究misère规则下一种新的公平组合游戏——Mouse游戏.确定出Mouse游戏的所有P位置,从而得到Mouse游戏的最优策略.

Establishment of an orthotopic pancreatic cancer mouse model: Cells suspended and injected in Matrigel

AIM: To establish an orthotopic mouse model of pancreatic cancer that mimics the pathological features of exocrine pancreatic adenocarcinoma.

Determination of trans-resveratrol in mouse liver by high performance liquid chromatography

To develop a sensitive high performance liquid chromatography （HPLC） assay for the determination of trans-resveratrol in mouse liver. The whole liver of a mouse was removed from the body, homogenated, and extracted by ethyl acetate. The organic layer was isolated and evaporated to dryness, the residue was reconstituted in 0.2 mL mobile phase for centrifugation, and 50 uL of the supernatant was injected into the/-IPLC instrument. The sample was separated on a Shimadzu ODS column （150 mm × 4.6 mm, 5 um） at 35 ℃ and detected by ultraviolet （UV） detector at the wavelength of 305 nm. The mobile phase consisted of methanol and 0.1 mol/L acetic acid （4：6, v/v） with the flow-rote at 1 mL/min. The limit of detection was 3.0 ng/g in liver homogenate with a signal/noise ratio of 3：1. The linear range of the calibration curve was 5.0-120.0 ng/g. The mean recoveries at the concentrations of 6, 10 and 80 ng/g were 102%, 96.0% and 91.5%, respectively. The RSDs for inter- and intra-day assays were less than 5%. Compared with other reported methods, this method was faster and more sensitive. It was also proved to be of good linearity, selectivity, accuracy and precision, and can be efficiently applied to the pharmacoldnetic study of trans-resveratrol in mouse liver.

Actin Visualization in Living Immature Pollen of Rice Using a GFP-Mouse Talin Fusion Protein

Green fluorescent protein (GFP) fused to the F_actin binding domain of mouse talin labels the actin cytoskeleton in the immature pollen of stable transformed rice (Oryza sativa L.) plants. Actin microfilaments could be visualized only in the late_developmental stage of the immature pollen. During this developmental stage, microfilaments, initially composed of very short fibrils, develop into a very complex and novel network that sometimes totally and sometimes partially encloses the vegetative nucleus and the spherical shaped generative cell in the central cytoplasm of the immature pollen. The behavior of the actin microfilamentous structure throughout the late_developmental stage of the immature pollen is extremely dynamic, and the likelihood of this structure in generating forces for vegetative nucleus and generative cell movement in the immature pollen has been discussed. No actin filaments were visualized in the spherical generative cells.