Isolation and Characterization of Cellulose Nanofiber(CNF)from Kenaf(Hibiscus cannabinus)Bast through the Chemo-Mechanical Process

The present work emphasizes the isolation of cellulose nanofiber(CNF)from the kenaf(Hibiscus cannabinus)bast through a chemo-mechanical process.In order to develop high CNF yield with superior properties of CNF for improving compatibility in varied applications this method is proposed.The fiber purification involved pulping and bleaching treatments,whereas mechanical treatment was performed by grinding and high-pressure treatments.The kraft pulping as a delignification method followed by bleaching has successfully removed almost 99%lignin in the fiber with high pulp yield and delignification selectivity.The morphology of the fibers was characterized by scanning electron microscopy,which showed a smooth surface,fiber bundles,gel-shaped nanofiber,and an average size of 94.05 nm with 69%of CNF in 34–100 nm size.The chemo-mechanical process exhibited a more crystalline nature in CNF than pulp kenaf.The low zeta potential values exhibit the distribution of fibrils and colloidal suspension stability without any further agglomeration.A lower concentration of CNF is less stable exhibiting the product agglomeration.Therefore,the chemo-mechanical process for the isolation of CNF(Hibiscus cannabinus)from kenaf involves sustainable,low-cost,non-toxic,and cheap alternatives than other traditional methods.

Engineered AAV13 variants with enhanced transduction and confined spread

Precise targeting of specific regions within the central nervous system(CNS)is crucial for both scientific research and gene therapy in the context of brain diseases.Adeno-associated virus 13(AAV13)is known for its restricted diffusion range within the CNS,making it an ideal choice for precise labeling and administration within small brain regions.However,AAV13 mediates relatively low expression of target genes.Here,we introduced specifically engineered modifications to the AAV13 capsid protein to enhance its transduction efficiency.We first constructed AAV13-YF by mutating tyrosine to phenylalanine on the surface of the AAV13 capsid.We then inserted the 7m8 peptide,known to enhance cell transduction,into positions 587/588 and 585/586 of the AAV13 capsid,resulting in two distinct variants named AAV13-587-7m8 and AAV13-585-7m8,respectively.We found that AAV13-YF exhibited superior in vitro infectivity in HEK293T cells compared to AAV13,while AAV13-587-7m8 and AAV13-585-7m8 showed enhanced CNS infection capabilities in C57BL/6 mice,with AAV13-587-7m8 infection retaining a limited spread range.These modified AAV13 variants hold promising potential for applications in gene therapy and neuroscience research.

The Antidepressant Mechanism of JiaWeiWenDan Decoction Regulating p38MAPK-ERK5 Signal Transduction Pathway

Objective: To investigate the anti-depression mechanism of JiaWeiWenDan Decoction in regulating p38MAPK-ERK5 signal transduction pathway. Methods: Depression model rats were randomly divided into Blank Control Group, Model Control Group, Chinese Medicine Treatment Group, and Western Medicine Treatment Group (hereinafter referred to as Blank Group, Model Group, Chinese Medicine Group, and Western Medicine Group), with 48 rats in each group. The mice were treated with p38MAPK-ERK5 on the 7th day, 14th day and 21st day, respectively, and the mice were treated for 28 days. The key targets and cytokines in p38MAPK-ERK5 signal transduction pathway were detected. Results: Compared with the Blank Group, the expression of p38MAPKmRNA in the hippocampus of the Model Group was increased. The Chinese Medicine Group and Western Medicine Group could reduce the expression of p38MAPK mRNA (P P P P Conclusion: The anti-inflammatory effect of JiaWeiWenDan Decoction may be related to the regulation of p38MAPK-ERK5 signaling pathway. With the advance of the treatment week, the best effect was obtained when the treatment was started on the 7th day of modeling.

Bibliometric analysis of the global research status and trends of mechanotransduction in cancer

BACKGROUND The development of cancer is thought to involve the dynamic crosstalk between the tumor cells and the microenvironment they inhabit.Such crosstalk is thought to involve mechanotransduction,a process whereby the cells sense mechanical cues such as stiffness,and translate these into biochemical signals,which have an impact on the subsequent cellular activities.Bibliometric analysis is a statistical method that involves investigating different aspects(including authors’names and affiliations,article keywords,journals and citations)of large volumes of literature.Despite an increase in mechanotransduction-related research in recent years,there are currently no bibliometric studies that describe the global status and trends of mechanotransduction-related research in the cancer field.AIM To investigate the global research status and trends of mechanotransduction in cancer from a bibliometric viewpoint.METHODS Literature on mechanotransduction in cancer published from January 1,1900 to December 31,2022 was retrieved from the Web of Science Core Collection.Excel and GraphPad software carried out the statistical analysis of the relevant author,journal,organization,and country information.The co-authorship,keyword cooccurrence,and keyword burst analysis were visualized with VOSviewer and CiteSpace.RESULTS Of 597 publications from 745 institutions in 45 countries were published in 268 journals with 35510 citation times.With 270 articles,the United States is a well-established global leader in this field,and the University of California system,the most productive(n=36)and influential institution(n=4705 citations),is the most highly active in collaborating with other organizations.Cancers was the most frequent publisher with the highest H-index.The most productive researcher was Valerie M.Weaver,with 10 publications.The combined analysis of concurrent and burst keywords revealed that the future research hotspots of mechanotransduction in cancer were related to the plasma membrane,autophagy,piezo1/2,heterogeneity,cancer diagnosis,and post-transcriptional modifications.CONCLUSION Mechanotransduction-related cancer research remains a hot topic.The United States is in the leading position of global research on mechano-oncology after almost 30 years of investigations.Research group cooperations exist but remain largely domestic,lacking cross-national communications.The next big topic in this field is to explore how the plasma membrane and its localized mechanosensor can transduce mechanical force through post-transcriptional modifications and thereby participate in cellular activity regulations and cancer development.

Impairment of the Endothelium and Disorder of Microcirculation in Humans and Animals Exposed to Infrasound due to Irregular Mechano-Transduction

The microcirculation of mammals is an autoregulated and complex synchronised system according to the current demand for nutrients and oxygen. The undisturbed course of vital functions such as of growth, blood pressure regulation, inflammatory sequence and embryogenesis is bound to endothelial integrity. The sensible vasomotion is particularly dependent on it. Mechano-transduction signalling networks play a critical role in vital cellular processes and are the decisive physiological mechanism for an adequate NO-release, main responsible for the autoregulation of vessels. Disturbed endothelial integrity, originating, e.g., from chronic oxidative stress and/or mechanic (oscillatory) stress, leads to disturbance of vasomotion as well as a disequilibrium of redox systems, recognized as main cause for the development of chronic inflammation diseases such as atherosclerosis and corresponding secondary illnesses, possibly cancer. The endothelial cytoskeleton, which corresponds to a viscoelastic “tensegrity model”, offers the possibility for mechano-transduction via its special construction. The rapidly growing knowledge about mechanical forces in cellular sensing and regulation of the last years (that culminated in the Nobel Prize award for the decoding of pressure/vibration sensing ion channels), led us to the following hypothesis: The extern stressor “Noise” produces under certain conditions an oscillatory stress field in the physiologically laminar flow bed of capillaries, which is able to lead to irregular mechano-transductions. Findings provide a strict dependence on frequency in mechano-transduction with determination of thresholds for a 1:1 transmission. The knowledge, recently gained on endothelial mechano-transduction, sheds a new light on the importance of low frequencies. This could indicate the long-sought pathophysiological way in which infrasound can exert a stressor effect at the cellular level. Noise-exposed citizens, who live near infrastructures such as a biogas installation, heat pumps, block-type thermal power stations and bigger industrial wind turbines (IWT’s), show worldwide mainly a symptomatology associated with microcirculatory disorder. Conceivable are also effects on insects or fishes, since the piezo-channels are recognised as conserved structures of all multicellular organism. An experimental design is proposed to demonstrate the direct pathological influence of infrasound of defined strength, frequency, effect/time profile and duration on the sensitive vasomotion.

Signal Transduction from Water Stress Perception to ABA Accumulation

To cope with unpredictably environmental perturbations and sometimes stresses, plants have evolved with some mechanisms so that these developing stresses can be sensitively perceived and the physiology can be rapidly regulated. Such perception and regulation can be a kind of feed_forward mechanism and may involve many biochemical and physiological processes and/or the expression of many genes. Although many dehydration_responsive genes have been identified, much fewer of their functions have been known. Such stress_ induced responses should include the initial perception of the dehydration signal, then the complicated signal transduction and cellular transmission until to the final gene activation or expression. As an important plant stress hormone abscisic acid (ABA) mediates many such responses. We believe that starting from the initial perception of dehydration to the gene expression leading to the stress_induced ABA biosynthesis is the most important stress signal transduction pathway among all the plant responses to stresses. Identification of the genes involved and understanding their roles during stress perception and physiological regulation shall be the most important and interesting research field in the coming years.

Involvement of cAMP in ABA Signal Transduction in Tobacco Suspension Cells

Abscisic acid (ABA) plays an important role in plant growth and developmental processes. Although some ABA signal molecules, such as cADPR, Ca2+, etc., have been reported, there. was no evidence proving the involvement of cAMP in A-B-A, signal transduction. In this present study, the constructed gene ( rd29A-GUS) was transformed into Nicotiana tabacum, and calli was induced from the transgenic plant. The suspension cells obtained from the callus grew well and uniformly. Treatment of the suspension cells with ABA led to an increase in GUS activity, indicating that these transgenic suspension cells are useful for the study of ABA signaling. Addition of nicotinamide (cADPR inhibitor) or U-73122 (phospholiphase C inhibitor) could only partially inhibit the increase of GUS activity elicited by ABA. The inhibitory effect of nicotinamide was enhanced by application of K252a (inhibitor of protein kinase). Treatment of the suspension cells with 8-Br-cAMP, a membrane-permeable analogue of cAMP, could partially replace the effect of ABA. Furthermore, intracellular addition of IBMX (phosphodiesterase inhibitor) mimicked die effect of exogenous cAMP on the deduction of expression of rd29A promoter. These results suggested that cAMP was an important messenger in ABA signal transduction in tobacco suspension cell.

Study on the Signal Transduction Pathway of Plant Defense to Pathogens

The immune responses of plants to foreign pathogens have developed relevant defense mechanisms, which formed complicated disease resistant signal transduction pathways. Salicylic acid（SA）, jasmonic acid（JA）/Ethylene（ET） and brassi- nosteroid （BR） could trigger the immune response to different pathogens in plants, making the plants show some resistance to the pathogens. The study on the trans- duction pathways of these three disease-resistant signals were introduced to provide some useful suggestions for the study on the transduction of disease-resistant sig- nals in plants.

The roles of the proteasome pathway in signal transduction and neurodegenerative diseases

There are two degradation systems in mammalian cells, autophagy/lysosomal pathway and ubiquitin-proteasome pathway. Proteasome is consist of multiple protein subunits and plays important roles in degradation of short-lived cellular proteins. Recent studies reveal that proteasomal degradation system is also involved in signal transduction and regulation of various cellular functions. Dysfunction or dysregulation of proteasomal function may thus be an important pathogenic mechanism in certain neurological disorders. This paper reviews the biological functions of proteasome in signal transduction and its potential roles in neurodegenerative diseases.

Transduction of Fas gene or Bcl-2 antisense RNA sensitizes cultured drug resistant gastric cancer cells to chemotherapeutic drugs

AIM To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid into SGC7901/VCR cells respectively, and to observe the expression of two genes in transfectants and non-transfectants as well as their drug sensitivity.METHODS Eukaryotic expression vector pBK-Fas cDNA and pDOR-anti Bcl-2 were constructed and transfected into SGC7901/VCR cells by lipofectamine, respectively. Northern blot and Western blot were used to detect the expression of mRNA and protein in SGC7901/VCR and SGC7901 cells and transfectants, and drug sensitivity of transfectants for VCR, CDDP and 5-FU was analyzed with MTT assay.RESULTS After gene transfection, 80 for Fas and 120 for antisense Bcl-2 drug-resistant clones were selected from 2×105 cells, transfection rate being 0.04% and 0.06%. Two clones of SGC7901 Fas/VCR cells and SGC7901 anti Bcl-2/VCR cells were randomly selected for further incubation. Hybridization results showed that the expression level of Fas mRNA and protein in SGC7901/VCR cells was much lower, but that of Bcl-2 mRNA and protein was higher than that in SGC7901 cells. The expression of Fas mRNA and protein in SGC7901 Fas/VCR cells was higher, and of Bcl-2 mRNA and protein was lower in SGC7901 anti Bcl-2/VCR cells than that in non-transfectants. MTT assay showed that transfectants were more sensitive to VCR, CDDP, 5-FU than non-transfectants.CONCLUSION Bcl-2 gene displayed high expression while Fas gene had low expression in drug resistant gastric cancer cells. Expression of Bcl-2 protein was effectively blocked in SGC7901 anti Bcl-2/VCR cells by gene transfection. In contrast, the expression of Fas mRNA and protein in SGC7901 Fas/VCR cells increased. Fas gene and Bcl-2 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to chemotherapeutic drugs. These results suggest cell apoptosis plays an important role in the mechanism of MDR, and enhancing apoptosis might reverse MDR.

Effect of emodin on mobility signal transduction system of gallbladder smooth muscle in Guinea pig with cholelithiasis

Objective: To study the effect of emodin on protein and gene expressions of the massagers in mobility signal transduction system of cholecyst smooth muscle cells in guinea pig with cholesterol calculus. Methods: The guinea pigs were randomly divided into 4 groups, such as control group, gall-stone(GS) group, emodin group and ursodesoxycholic acid(UA) group. Cholesterol calculus models were induced in guinea pigs of GS, emodin and UA groups of induced models by lithogenic diet, while emodin or UA were given to the corresponding group for 7 weeks. The histomorphological and ultrastructure change of gallbladder were detected by microscope and electron microscope, the content of plasma cholecystokinin(CCK) and [Ca^(2+)]i were analyzed successively by radioimmunoassay and flow cytometry. The protein and mR NA of Gsα, Giα and Cap in cholecyst cells were determined by western blotting and real time polymerase chain reaction(RT-PCR). Results: Emodin or UA can relieve pathogenic changes in epithelial cells and muscle cells in gallbladder of guinea pig with cholesterol calculus by microscope and transmission electron microscope. In the cholecyst cells of GS group, CCK levels in plasma and [Ca^(2+)]i decreased, the protein and m RNA of GS group were downregulated,the protein and m RNA of Gi and Cap were up-regulated. Emodin significantly decreased the formative rate of gallstone, improved the pathogenic change in epithelial cells and muscle cells, increased CCK levels in plasma and [Ca^(2+)]i in cholecyst cells, enhanced the protein and mR NA of Gs in cholecyst cells, reduced the protein and mR NA of Gi and Cap in cholecyst cells in guinea pig with cholesterol calculus. Conclusion: The dysfunction of gallbladder contraction gives rise to the disorders of mobility signal transduction system in cholecyst smooth muscle cells, including low content of plasma CCK and [Ca^(2+)]i in cholecyst cells, abnormal protein and mRNA of Gs, Gi and Cap. Emodin can enhance the contractibility of gallbladder and alleviate cholestasis by regulating plasma CCK levels, [Ca2+]i in cholecyst cells and the protein and mR NA of Gs, Gi and Cap.

Influence on Cellular Signal Transduction Pathway in Dairy Cow Mammary Gland Epithelial Cells by Galactopoietic Compound Isolated from Vaccariae segetalis

The galactopoietic mechanism of Vaccaria segetalis is still unknown. Understanding dibutyl phthalate （DBP） separated from Vaccaria segetalis on the expression of lactation signal transduction genes of mammary gland epithelial cells, including prlr, erα, akt1, socs2, pparγ and elf5, will be helpful to reveal the molecular mechanism. Western blot and qRT- PCR were used to study the change of prlr, erα, akt, socs2, pparγ, and elf5 expression at mRNA and protein level. Co- localization expression of prolactin receptor （PRLR） and estrogen receptor α （ERα） was observed by immunofluorescence; the expression changes of miRNAs （21, 125b, 143, and 195） and the secretion of β-casein and lactose were detected by qRT-PCR and RP-HPLC. The results showed that Vaccaria segetalis active compound had similar fuctions as estrogen and/or prolactin （PRL） in dairy cow mammary gland epithelial cells （DCMECs）, increased the expressions of prlr, erα, akt1, and elf5 genes, while repressed pparγ expressions. DBP promoted socs2 mRNA expression, but its protein expressions were repressed. Furthermore, both DBP and PRL could repress the expressions of miRNA-125b, miRNA-143 and miRNA- 195 in DCMECs. DBP could repress the expression of miRNA-21, while the influence of PRL on miRNA-21 was not certain. DBP could promote the lactation ability of DCMECs by regulating the ER and PRLR cellular signal transduction pathway.

The Erythropoietin Receptor: Dimerization and Intracellular Signal Transduction

Erythropoietin (EPO), a 34 kD glycopro-tein, is the principal growth factor regulating theproduction of circulating erythrocytes; EPO isessential for committed CFU - E erythroid pro-genitors to divide several times and then to dif-ferentiate into erythrocytes. Like most receptorsfor hematopoietic growth factors, the erythro-poietin receptor (EPO - R) is a type I trans-membrane protein and a member of the cytokinereceptor superfamily. These receptors containfour conserved cysteines and a Trp - Ser - X -

PrP^C-related signal transduction is influenced by copper, membrane integrity and the alpha cleavage site

The copper-binding, membrane-anchored, cellular prion protein （PrP~） has two constitutive cleavage sites producing distinct N- and C-terminal fragments （N1/C1 and N2/C2）. Using RK13 cells expressing either human PrPc, mouse PrPc or mouse PrP^C carrying the 3F4 epitope, this study explored the influence of the PrP^C primary sequence on endoproteolytic cleavage and one putative PrPc function, MAP kinase signal transduction, in response to exogenous copper with or without a perturbed membrane environment. PrPc primary sequence, especially that around the N1/C1 cleavage site, appeared to influence basal levels of proteolysis at this location and extracellular signal-regulat- ed kinase 1/2 （ERK1/2） phosphorylation, with increased processing demonstrating an inverse relationship with basal ERK1/2 activation. Human PrP^C showed increased N1/C1 cleavage in response to copper alone, accompanied by specific p38 and JNK/SAPK phosphorylation. Combined exposure to copper plus the cholesterol-sequestering antibiotic filipin resulted in a mouse PrP^C-specific substantial increase in signal protein phosphorylation, accompanied by an increase in N1/C1 cleavage. Mouse PrPc harboring the human N1/C1 cleavage site assumed more human-like profiles basally and in response to copper and altered membrane environments. Our results demonstrate that the PrPc pri- mary sequence around the N1/C1 cleavage site influences endoproteolytic processing at this location, which appears linked to MAP kinase signal transduction both basally and in response to copper. Further, the primary sequence appears to confer a mutual dependence of N1/C1 cleavage and membrane integrity on the fidelity of PrP^C-related signal transduction in response to exogenous stimuli.

p38 MAPK is a Component of the Signal Transduction Pathway Triggering Cold Stress Response in the MED Cryptic Species of Bemisia tabaci

Cold stress responses help insects to survive under low temperatures that would be lethal otherwise.This phenomenon might contribute to the invasion of some Bemisia tabaci cryptic species from subtropical areas to temperate regions.However,the molecular mechanisms regulating cold stress responses in whitefly are yet unclear.Mitogen-activated protein kinases（MAPKs）which including p38,ERK,and JNK,are well known for their roles in regulating metabolic responses to cold stress in many insects.In this study,we explored the possible roles of the MAPKs in response to low temperature stresses in the Mediterranean cryptic species（the Q-biotype）of the B.tabaci species complex.First,we cloned the p38 and ERK genes from the whitefly cDNA library.Next,we analyzed the activation of MAPKs during cold stress in the Mediterranean cryptic species by immuno-blotting.After cold stress,the level of phospho-p38 increased but no significant change was observed in the phosphorylation of ERK and JNK,thus suggesting that the p38 might be responsible for the defense response to low temperature stress.Furthermore,we demonstrated that：i）3 min chilling at 0°C was sufficient for the activation of p38 MAPK pathway in this whitefly;and ii）the amount of phosphorylated p38 increased significantly in the first 20 min of chilling,reversed by 60 min,and then returned to the original level by 120 min.Taken together,our results suggest that the p38 pathway is important during response to low temperature stress in the Mediterranean cryptic species of the B.tabaci species complex.

TIP30 regulates apoptosis-related genes in its apoptotic signal transduction pathway

AIM: To investigate the role of TIP30 in apoptotic signal pathway in hepatoblastoma cells and to provide a basis for TIP30 as a gene therapy candidate in the regression of hepatoblastoma cells. METHODS: Apoptosis of human hepatoblastoma cell lines HepG2 (p53 wild), Hep3B (p53 null) and PLC/RPF/5 (p53 mutant) infected with Ad-TIP30 (bearing a wild type human Tip30 gene) were analyzed and p53, Bax and Bcl-xl expression levels were compared among these cells. MTT assay, DNA fragmentation, in situ 3' end labeling of DNA, annexin-V FITC staining were used to detect cell death and apoptosis in cells at various time intervals subsequent to infection, and to determine whether TIP30 had an effect on the expression levels of some apoptosis-related gene products such as Bax, p53 and Bcl-xl. A similar time course experiment was performed by Western blotting. RESULTS: In MTT assay, the viability of HepG2 cells decreased significantly from 99.7% to 10% and displayed more massive cell death within 5-8 d than Hep3B and PLC/ RPF/5 cells, with their viability decreased from 97.8% to 44.3% and 98.1% to 50.4%, respectively. In annexin-V FITC assay, the percentage of apoptosis cells in HepG2 cells was two to three-fold higher than that in control cells (infected with Ad-GFP), two-fold higher than that in Hep3B cells and 1.4-fold higher than that in PLC/RPF/5 cells 36 h after infection, respectively. Moreover, in HepG2 cells, the p53 began to increase 6-8 h after infection, reaching a maximum level between 8 and 12 h after infection and then dropped. Bax showed a similar increase in the cells as p53 reached the maximum at 8-12 h and subsequently decreased. Interestingly, Bcl-xl protein levels were down regulated during 24 to 36 h after Ad-TIP30 infection. In contrast, ectopic expression of TIP30 in Hep3B and PLC/ RPF/5 cells had no effect on the regulation of Bax expression, but had an effect on Bcl-xl levels. In comparison with HepG2 cells, these data suggested that up-regulation of p53 levels by TIP30 might be a pre-requisite for Bax and Bax/Bcl-xl ratio increase. We hypothesied that TIP30 might regulate Bax gene partly through p53, which sensitizes cells to apoptosis by involving a p53 apoptosis signal transduction pathway. CONCLUSION: TIP30 plays an important role in predisposing hepatoblastoma cells to apoptosis through regulating expression levels of these genes. Ad-TIP30 carrying exogenous TIP30-anti-tumor genes may be regarded as a potential candidate for the treatment of hepatocellular carcinoma.

Soluble expression of recomb inant cMyc,Klf4,Oct4,and Sox2 proteins in bacteria and transduction into living cells

AIM：To develop a new method to produce recombinant reprogramming proteins,c Myc,Klf4,Oct4,and Sox2,in soluble format with low cost for the generation of induced pluripotent stem cells（i PSCs）.METHODS：A short polypeptide sequence derived from the HIV trans-activator of transcription protein（TAT） and the nucleus localization signal（NLS） polypeptide were fused to the N terminus of the reprogramming proteins and they were constructed into p Cold-SUMO vector which can extremely improve the solubility of recombinant proteins.Then these vector plasmids were transformed into E.coli BL21（DE3） Chaperone competent cells for amplification.The solubility of these recombinant proteins was determined by SDS-PAGE and Coomassie brilliant blue staining.The recombinant proteins were purified by NiNTA resin and identified by Western blot.The transduction of these proteins into HEK 293 T cells were evaluated by immunofluorescence staining.RESULTS：These four reprogramming proteins could be produced in soluble format in p Cold-SUMO expression vector system with the assistance of chaperone proteins in bacteria.The proteins were purified successfully with a purity of over 70% with a relative high transduction rate into 293 cells.CONCLUSION：The results in the present study indicate the four important reprogramming proteins,c Myc,Klf4,Oct4,and Sox2,can be produced in soluble format in bacteria with low cost.Our new method thus might be expected to greatly contribute to the future study of i PSCs.

Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus

In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.

Influence of CO_2 pneumoperitoneum on intracellular pH and signal transduction in cancer cells

Object: The authors studied the influence of CO2 pneumoperitoneum on intracellular pH and signal transduction arising from cancer cell multiplication in laparoscopic tumor operation. Method: They set up a simulation of pneumoperitoneum under different CO2 pressure, and then measured the variation of intracellular pH (pHi) at different time and the activity of protein kinase C (PKC) and protein phosphatase 2a (PP2a) at the end of the pneumoperitoneum. After 1 week, the concentration of cancer cells in the culture medium was calculated. Result: When the pressure of CO2 pneumoperitoneum was 0, 10, 20, 30 mmHg respectively, the average pHi was 7.273, 7.075, 6.783, 6.693 at the end of the pneumoperitoneum; PKC activity was 159.4, 168.5,178.0, 181.6 nmol/(g.min) and PP2a was 4158.3, 4066.9, 3984.0, 3878.5 nmol/(g.min) respectively. After 1 week, the cancer cells concentration was 2.15×105, 2.03×105, 2.20×105, 2.18×105 L-1. Conclusion: CO2 pneumoperitoneum could promote acidosis in cancer cells, inducing the activation of protein kinase C and deactivation of protein phosphatase 2a, but it could not accelerate the mitosis rate of the cancer cells.

Roles of ABA Signal Transduction during Higher Plant Seed Development and Germination

ABA is one of the 5 phytohormones in higher plants, which is also the most important hormone that regulates higher plants in response to environmental stress, by ABA signal transduction. Understanding ABA signal transduction at the molecular level is crucial to biology and ecology, and rational breeding complied with corresponding eco-environmental changes. Great advancements have taken place over the past 10 years by application of the Arabidopsis experimental system. Many components involved in ABA signal transduction have been isolated and identified and a clear overall picture of gene expression and control for this transduction has become an accepted fact. On the basis of the work in our laboratory, in conjunction with the data available at the moment, the authors have attempted to integrate ABA signal transduction pathways into a common one and give some insights into the relationship between ABA signal transduction and other hormone signal transduction pathways, with an emphasis upon the ABA signal transduction during higher plant seed development. A future challenge in this field is that different experimental systems are applied and various receptors and genes need to be characterized through the utilization of microarray chips.