Electroacupuncture facilitates vascular normalization by inhibiting Glyoxalase1 in endothelial cells to attenuate glycolysis and angiogenesis in triple-negative breast cancer.

Recent therapeutic strategies for the treatment of triple-negative breast cancer (TNBC) have shifted the focus from vascular growth factors to endothelial cell metabolism. This study highlights the underexplored therapeutic potential of peri-tumoral electroacupuncture, a globally accepted non-pharmacological intervention for TNBC, and molecular mechanisms. Our study showed that peri-tumoral electroacupuncture effectively reduced the density of microvasculature and enhanced vascular functionality in 4T1 breast cancer xenografts, with optimal effects on day 3 post-acupuncture. The timely integration of peri-tumoral electroacupuncture amplified the anti-tumor efficacy of paclitaxel. Multi-omics analysis revealed Glyoxalase 1 (Glo1) and the associated methylglyoxal-glycolytic pathway as key mediators of electroacupuncture-induced vascular normalization. Peri-tumoral electroacupuncture notably reduced Glo1 expression in the endothelial cells of 4T1 xenografts. Using an in vivo matrigel plug angiogenesis assay, we demonstrated that either Glo1 knockdown or electroacupuncture inhibited angiogenesis. In contrast, Glo1 overexpression increased blood vessel formation. In vitro pharmacological inhibition and genetic knockdown of Glo1 in human umbilical vein endothelial cells inhibited proliferation and promoted apoptosis via downregulating the methylglyoxal-glycolytic pathway. The study using the Glo1-silenced zebrafish model further supported the role of Glo1 in vascular development. This study underscores the pivotal role of Glo1 in peri-tumoral electroacupuncture, spotlighting a promising avenue for enhancing vascular normalization and improving TNBC treatment outcomes.

[Research status and trends of acupuncture and moxibustion for cancer：a bibliometric analysis based on CiteSpace and VOSviewer].

To analyze the research status of acupuncture and moxibustion for cancer at home and abroad in the past 45 years by using bibliometric and scientific knowledge map methods，and explore the development trends in future. The literature of acupuncture and moxibustion for cancer was retrieved from CNKI and Web of Science (WOS) till December 31, 2020 since the database establishment, and CiteSpace and VOSviewer software were used to perform visual map analysis through cooperation network, keyword co-occurrence, keyword timeline, keyword emergence and other methods. Totally, 1 585 literature in CNKI and 1 564 literature in WOS were included, and the annual publication amount showed a fluctuating upward trend. Cooperation between countries was centered on China and the United States, and there was relatively little cooperation among different institutions. The analysis of keyword and cited literature showed that researches focused on the control of acupuncture and moxibustion therapy on cancer complications and adverse reactions of western medicine. The main research types in WOS were systematic review and randomized controlled trial (RCT), while in CNKI was review, depth studies on mechanism of acupuncture and moxibustion for cancer were rare. The concern about the quality of life of cancer patients may become research emphasis in the field of acupuncture and moxibustion for cancer in future, and the research scope tends to integrative and holistic oncology.

SnRK2.6 interacts with phytochrome B and plays a negative role in red light-induced stomatal opening.

Light is an important environmental factor for plant growth and development. Phytochrome B (phyB), a classical red/far-red light receptor, plays vital role in controlling plant photomorphogenesis and light-induced stomatal opening. Phytohormone abscisic acid (ABA) accumulates rapidly and triggers a series of physiological and molecular events during the responses to multiple abiotic stresses. Recent studies showed that phyB mutant synthesizes more ABA and exhibits improved tolerance to salt and cold stress, suggesting that a crosstalk exists between light and ABA signaling pathway. However, whether ABA signaling components mediate responses to light remains unclear. Here, we showed that SnRK2.6 (Sucrose Nonfermenting 1-Related Protein Kinase 2.6), a key regulator in ABA signaling, interacts with phyB and participates in light-induced stomatal opening. First, we checked the interaction between phyB and SnRK2s, and found that SnRK2.2/2.3/2.6 kinases physically interacted with phyB in yeast and in vitro. We also performed co-IP assay to support that SnRK2.6 interacts with phyB in plant. To investigate the role of SnRK2.6 in red light-induced stomatal opening, we obtained the snrk2.6 mutant and overexpression lines, and found that snrk2.6 mutant exhibited a significantly larger stomatal aperture under red light treatment, while the two independent overexpression lines showed significantly smaller stomatal aperture, indicative of a negative role for SnRK2.6 in red light-induced stomatal opening. The interaction of SnRK2.6 with red light receptor and the negative role of SnRK2.6 in red light-induced stomatal opening provide new evidence for the crosstalk between ABA and red light in guard cell signaling.

RIC7 plays a negative role in ABA-induced stomatal closure by inhibiting H2O2 production.

When plants encounter environmental stresses, phytohormone abscisic acid (ABA) accumulates quickly and efficiently reduces water loss by inducing stomatal closure. Reactive oxygen species (ROS) is an important regulator in ABA-induced stomatal closure, and ROS generation is modulated by multiple components in guard-cell ABA signaling. ROP interactive CRIB-containing protein 7 (RIC7) has been found to negatively regulate ABA-induced stomatal closure. However, the molecular details of the RIC7 function in this process are unclear. Here, by using two RIC7 overexpressing mutants, we confirmed the negative role of RIC7 in ABA-induced stomatal closure and found that guard cells of RIC7 overexpressing mutants generated less H2O2 than the wild type with ABA treatment, which were consistent with the reduced expression levels of ROS generation related NADPH oxidase genes AtRBOHD and AtRBOHF, and cytosolic polyamine oxidase genes PAO1 and PAO5 in the RIC7 overexpressing mutants. Furthermore, external applied H2O2 failed to rescue the defects of stomatal closure in RIC7 overexpressing mutants. These results suggest that RIC7 affects H2O2 generation in guard cells, and the function of H2O2 is dependent on RIC7 in ABA-induced stomatal closure, indicative of interdependency between RIC7 and H2O2 in ABA guard-cell signaling.

Phosphorylation of plasma membrane aquaporin PIP2;1 in C-terminal affects light-induced stomatal opening in Arabidopsis.

Guard cells undergo quick volume changes during stomatal movements. However, the contribution of aquaporins to stomatal movements has not been well understood. The plasma membrane aquaporin PIP2;1in Arabidopsis has been found to mediate abscisic acid-induced or flag22-induced stomatal closure. In this research, we investigated the role of PIP2;1 in light-induced stomatal opening by measuring the stomatal apertures of the pip2;1 mutant and PIP2;1 overexpression lines after light treatment. pip2;1 mutant exhibited a larger stomatal aperture, and the overexpression lines displayed a smaller stomatal aperture. It has been reported that the phosphorylation at Ser-280 and Ser-283 of PIP2;1 in rosette tissue increased in response to darkness, whereas osmotic water permeability (Pf) in mesophyll protoplasts in darkness was lower than that under light, suggesting that phosphorylation at Ser-280 and Ser-283 of PIP2;1 affected Pf in mesophyll protoplasts. Therefore, we obtained the pip2;1 mutant expressing phosphorylation-deficient (PIP2;1 AA) or phosphomimetic (PIP2;1 DD) forms of PIP2;1. The PIP2;1 AA lines exhibited a larger stomatal aperture as pip2;1 mutant, whereas PIP2;1 DD lines exhibited a smaller stomatal aperture as PIP2;1 overexpression lines under light. These results suggest that PIP2;1 plays a negative role in light-induced stomatal opening, and phosphorylation of PIP2;1 at Ser-280 and Ser-283 causes reduced water absorption in guard cells and decreased stomatal opening.

The RopGEF2-ROP7/ROP2 Pathway Activated by phyB Suppresses Red Light-Induced Stomatal Opening.

Circadian rhythm of stomatal aperture is mainly regulated by light/darkness. Blue and red light induce stomatal opening through different mechanisms that are mediated by special receptors. ROP2, a member of Rho GTPase family in Arabidopsis (Arabidopsisthaliana), has been found to negatively regulate light-induced stomatal opening. However, the upstream guanine nucleotide exchange factor (GEF) RopGEFs have not been revealed, and it is unclear which photoreceptor is required for the action of RopGEFs-ROPs. Here, we showed that RopGEF2 acted as a negative regulator in phytochrome B (phyB)-mediated red light-induced stomatal opening. Meanwhile, ROP7, another member of ROP family, acting redundantly with ROP2, was regulated by RopGEF2 in this process. RopGEF2 interacted with ROP7 and ROP2 and enhanced their intrinsic nucleotide exchange rates. Furthermore, the direct interactions between phyB and RopGEF2 were detected in vitro and in plants, and phyB enhanced the GEF activity of RopGEF2 toward both ROP7 and ROP2 under light. In addition, RopGEF4 functioned redundantly with RopGEF2 in red light-induced stomatal opening by activating both ROP7 and ROP2, and RopGEF2/RopGEF4 acted genetically downstream of phyB; however, the GEF activity of RopGEF4 was not directly enhanced by phyB. These results revealed that red light-activated phyB enhances the GEF activities of RopGEF2 and RopGEF4 directly or indirectly, and then activate both ROP7 and ROP2 in guard cells. The negative mechanism triggered by phyB prevents the excessive stomatal opening under red light.

GUS Staining of Guard Cells to Identify Localised Guard Cell Gene Expression.

Determination of a gene expression in guard cells is essential for studying stomatal movements. GUS staining is one means of detecting the localization of a gene expression in guard cells. If a gene is specially expressed in guard cells, the whole cotyledons or rosette leaf can be used for GUS staining. However, if a gene is expressed in both mesophyll and guard cells, it is hard to exhibit a clear expression of the gene in guard cells by a GUS staining image from leaf. To gain a clear guard cell GUS image of small G protein ROP7, a gene expressed in both mesophyll and guard cells, we peeled the epidermal strips from the leaf of 3-4 week-old plants. After removing the mesophyll cells, the epidermal strips were used for GUS staining. We compared the GUS staining images from epidermal strips or leaf of small G protein ROP7 and RopGEF4, a gene specifically expressed in guard cells, and found that GUS staining of epidermal strips provided a good method to show the guard cell expression of a gene expressed in both mesophyll and guard cells. This protocol is applicable for any genes that are expressed in guard cells of Arabidopsis, or other plants that epidermal strips can be easily peeled from the leaf.

Species phylogeny and diversification process of Northeast Asian Pungitius revealed by AFLP and mtDNA markers.

Pungitius is a highly diversified genus of sticklebacks (Gasterosteidae) occurring widely in northern parts of the Northern Hemisphere. Several ecologically and genetically divergent types that are largely isolated reproductively but occasionally hybridize in sympatry have been discovered in Northeast Asia, although the taxonomy and evolutionary relationships among them remain unclear. We used amplified fragment length polymorphism (AFLP) and mitochondrial DNA (mtDNA) markers to infer phylogenies among individuals collected from sympatric and allopatric populations, including the type localities of the described species. Phylogenetic analyses based on 2683 polymorphic AFLP loci confirmed seven species, each of which (except for one entirely allopatric species P. platygaster) was clearly differentiated from one or two other sympatric species and constituted a highly supported monophyletic clade with conspecific allopatric populations. The phylogeny showed that two lineages arose early; one gave rise to two species (circumpolar species P. pungitius and Paratethys species P. platygaster) and the other to five species endemic to Northeast Asia (P. sinensis, P. tymensis, P. polyakovi, P. kaibarae, and P. bussei). The brackish-water, freshwater, and Omono types previously discovered in Japan were reidentified as P. pungitius, P. sinensis, and P. kaibarae, respectively. A marked incongruence was noted between the phylogenies of AFLP and mtDNA markers, suggesting the occasional occurrence of hybridization and mtDNA introgression among distinct species. Our results highlight that the marginal seas of Northeast Asia played a key role as barriers to or facilitators of gene flow in the evolution of species diversity of Pungitius concentrated in this region.

Revalidation and redescription of Brachymystax tsinlingensis Li, 1966 (Salmoniformes: Salmonidae) from China.

Brachymystax tsinlingensis Li, 1966 is revalidated and redescribed. It can be distinguished from all congeners by the following combination of characteristics: no spots on operculum; gill rakers 15-20; lateral-line scales 98-116; pyloric caeca 60-71. Unique morphological characters and genetic divergence of this species are discussed. This species has a limited distribution in several streams of the middle part of the Qinling Mountains in China. Methods for management and protection of B. tsinlingensis need to be re-evaluated.

Functional roles of three cutin biosynthetic acyltransferases in cytokinin responses and skotomorphogenesis.

Cytokinins (CKs) regulate plant development and growth via a two-component signaling pathway. By forward genetic screening, we isolated an Arabidopsis mutant named grow fast on cytokinins 1 (gfc1), whose seedlings grew larger aerial parts on MS medium with CK. gfc1 is allelic to a previously reported cutin mutant defective in cuticular ridges (dcr). GFC1/DCR encodes a soluble BAHD acyltransferase (a name based on the first four enzymes characterized in this family: Benzylalcohol O-acetyltransferase, Anthocyanin O-hydroxycinnamoyltransferase, anthranilate N-hydroxycinnamoyl/benzoyltransferase and Deacetylvindoline 4-O-acetyltransferase) with diacylglycerol acyltransferase (DGAT) activity in vitro and is necessary for normal cuticle formation on epidermis in vivo. Here we show that gfc1 was a CK-insensitive mutant, as revealed by its low regeneration frequency in vitro and resistance to CK in adventitious root formation and dark-grown hypocotyl inhibition assays. In addition, gfc1 had de-etiolated phenotypes in darkness and was therefore defective in skotomorphogenesis. The background expression levels of most type-A Arabidopsis Response Regulator (ARR) genes were higher in the gfc1 mutant. The gfc1-associated phenotypes were also observed in the cutin-deficient glycerol-3-phosphate acyltransferase 4/8 (gpat4/8) double mutant [defective in glycerol-3-phosphate (G3P) acyltransferase enzymes GPAT4 and GPAT8, which redundantly catalyze the acylation of G3P by hydroxyl fatty acid (OH-FA)], but not in the cutin-deficient mutant cytochrome p450, family 86, subfamily A, polypeptide 2/aberrant induction of type three 1 (cyp86A2/att1), which affects the biosynthesis of some OH-FAs. Our results indicate that some acyltransferases associated with cutin formation are involved in CK responses and skotomorphogenesis in Arabidopsis.

Lacking chloroplasts in guard cells of crumpled leaf attenuates stomatal opening: both guard cell chloroplasts and mesophyll contribute to guard cell ATP levels.

Controversies regarding the function of guard cell chloroplasts and the contribution of mesophyll in stomatal movements have persisted for several decades. Here, by comparing the stomatal opening of guard cells with (crl-ch) or without chloroplasts (crl-no ch) in one epidermis of crl (crumpled leaf) mutant in Arabidopsis, we showed that stomatal apertures of crl-no ch were approximately 65-70% those of crl-ch and approximately 50-60% those of wild type. The weakened stomatal opening in crl-no ch could be partially restored by imposing lower extracellular pH. Correspondingly, the external pH changes and K(+) accumulations following fusicoccin (FC) treatment were greatly reduced in the guard cells of crl-no ch compared with crl-ch and wild type. Determination of the relative ATP levels in individual cells showed that crl-no ch guard cells contained considerably lower levels of ATP than did crl-ch and wild type after 2 h of white light illumination. In addition, guard cell ATP levels were lower in the epidermis than in leaves, which is consistent with the observed weaker stomatal opening response to white light in the epidermis than in leaves. These results provide evidence that both guard cell chloroplasts and mesophyll contribute to the ATP source for H(+) extrusion by guard cells.

[Review on taxonomical studies of Chinese inland-water fish].

We reviewed the taxonomy and systematics research history of freshwater fish in China based on 1 236 taxonomic literature records on Chinese freshwater fish. The research was divided into five research periods according to specific historical events: (1) period by foreign scholars, (2) period with Chinese scholars, (3) period during World War II and Civil War, (4) recovery period and (5) period of rapid development. There were representative studies and innovations in all periods. We also discuss here the characteristics of each period on the basis of literature analysis.

[Validation and re-description of Sinocyclocheilus aluensis Li et Xiao, 2005 (Cypriniforms: Cyprinidae)].

Sinocyclocheilus aluensis was previously synonymized with S. angustiporus, but through the comparison of the specimens collected from Luxi County (type locality of S. aluensis) and type specimens of S. angustiporus, we identified several clear and stable characteristics to distinguish them. These findings suggest that S. aluensis should be considered as a valid species, as it can be distinguished from S. angustiporus by the position of the dorsal-fin insertion (posterior to vs. opposite to the pelvic-fin insertion), eye (22.4%-29.7% vs. 26.4%-38.9%, percentage of head length), eye-ball diameter (16.0%-23.6% vs. 21.3%-29.0%), and interorbital width (21.0%-32.3% vs. 19.7%-22.6%).

[Poly (allylamine)-stabilized colloidal copper nanoparticles: synthesis and their SERS activities].

Poly(allylamine)-stabilized spherical and rod-shaped copper nanoparticles were synthesized by a simple chemical reaction. The synthesis was performed by the reduction of copper (II) salt with hydrazine in aqueous solution under atmospheric air in the presence of poly(allylamine) (PAAm) capping agent. Besides providing long-term stability to the nanoparticles by preventing particle agglomeration, polymer capping agents such as PAAm make the particles dispersible in aqueous solution. Noteworthy advantages of the synthetic method include its production of water dispersible nanoparticles at room temperature without inert atmosphere, making the synthesis more environmentally friendly. The resulting copper nanoparticles were investigated by UV-Vis spectroscopy and transmission electron microscopy. The authors found that several factors, including the amount of NaOH solution, concentration of PAAm, and reaction time, affect the composition, size, morphology, and degree of agglomeration of the resulting copper nanoparticles. The amount of NaOH in the reaction is crucial for the synthesis to result in either pure copper or copper oxide-containing copper nanoparticles as well as to produce the highest possible yield of copper nanoparticles. In addition, the reaction time and concentration of PAAm play key roles in controlling the size and shape of the nanoparticles, respectively. The resulting colloidal copper nanoparticles exhibit large surface-enhanced Raman spectroscopy (SERS) signals.

Functional characterization of the CKRC1/TAA1 gene and dissection of hormonal actions in the Arabidopsis root.

Cytokinin (CK) influences many aspects of plant growth and development, and its function often involves intricate interactions with other phytohormones such as auxin and ethylene. However, the molecular mechanisms underlying the role of CK and its interactions with other growth regulators are still poorly understood. Here we describe the isolation and characterization of the Arabidopsis CK-induced root curling 1 (ckrc1) mutant. CKRC1 encodes a previously identified tryptophan aminotransferase (TAA1) involved in the indole-3-pyruvic acid (IPA) pathway of indole-3-acetic acid (IAA) biosynthesis. The ckrc1 mutant exhibits a defective root gravitropic response (GR) and an increased resistance to CK in primary root growth. These defects can be rescued by exogenous auxin or IPA. Furthermore, we show that CK up-regulates CKRC1/TAA1 expression but inhibits polar auxin transport in roots in an AHK3/ARR1/12-dependent and ethylene-independent manner. Our results suggest that CK regulates root growth and development not only by down-regulating polar auxin transport, but also by stimulating local auxin biosynthesis.

[Determination of effective components in different positions of Panax notoginseng by HPLC].

OBJECTIVE: A quantitative method was developed by gradient elution for the determination of notoginsenoside R1, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 in different positions of Panax Notoginseng by HPLC. The content of 4 kinds saponins in different positions of Panax Notoginseng were compared. METHODS: The different positions of Panax notoginseng (including root, rhizome, branch root, leaf, flower) were extracted with methanol. The HPLC condition was as following: Kromasil C18 column (250 mm x 4.6 mm, 5 microm), acetonitrile and water linearity gradient elution, flow rate at 1.0 mL/min, column temperature at 25 degrees C, wavelength 203 nm. RESULTS: The linear ranges of notoginsenoside R1, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 were 4.4-440 microg/mL, 4.32-1080 microg/mL, 4.24-212 microg/mL and 4.48-1120 microg/mL, respectively. The RSD (n=5) of average contents of intra-day and inter-day of 4 kinds saponins were 0.46%, 0.24%, 0.77%, 0.68% and 1.64%, 0.69%, 0.52%, 0.65%, respectively. The average recoveries were (102.93 +/- 1.22)%, (103.18 +/- 0.49)%, (103.20 +/- 1.58)%, (103.86 +/- 0.39)%, respectively. The content of 4 kinds saponins in different position of Panax notoginseng was: rhizome > root > branch root > flower > leaf; the content of 4 kinds saponin in the root of Panax notoginseng was: 80 pieces in 500 g >60 pieces in 500 g >20 pieces in 500 g >40 pieces in 500 g >100 pieces in 500 g. CONCLUSION: This method is simple, sensitive, accurate and repeat, and is suitable in determination of the content of 4 kinds saponins in different positions of Panax notoginseng.

Pharmacokinetics, toxicity of nasal cilia and immunomodulating effects in Sprague-Dawley rats following intranasal delivery of thymopentin with or without absorption enhancers.

Thymopentin (TP 5), a synthetic pentapeptide, has been used in clinic as a modulator for immnuodeficiencies through intramuscular administration. The objectives of this study was to investigate the pharmacokinetics using normal rats and toxicity of nasal cilia as well as immunomodulating effects using immunosuppression rats after intranasal delivery of thymopentin with or without an absorption enhancer. The absorption extent of fluorescein isothiocyanate (FITC) labeled TP 5 via nasal delivery at a single dose is significantly improved by incorporating sodium deoxycholate, Brij 35 and chitosan, respectively. FITC-TP 5 can also be absorbed to such an extent ranging from 15 to 28% after intranasal administration of FITC-TP 5 alone, FITC-TP 5 with sodium caprylate, or with bacitracin, respectively. After seven consecutive days multiple dosing, TP 5 formulation with sodium deoxycholate or Brij 35 caused apparently injury to nasal cilia, indicating these two enhancers would not be appropriate for nasal delivery. Results from superoxide dismutase activity, maleic dialdehyde, T-lymphocyte subsets (CD3+, CD4+, CD8+ and CD4+/CD8+ ratio) analyses suggest that all the selected enhancers improve the modulating effects of TP 5 in the immunosuppression rats. On an overall evaluation, intranasal TP 5 alone, TP 5 with chitosan, or TP 5 with bacitracin formulation may be suitable for the future clinical application.

Antisense suppression of deoxyhypusine synthase in tomato delays fruit softening and alters growth and development.

The effects of suppressing deoxyhypusine synthase (DHS) have been examined in tomato (Solanum lycopersicum cv UCT5). DHS mediates the first of two sequential enzymatic reactions that activate eukaryotic translation initiation factor-5A (eIF-5A) by converting a conserved Lys to the unusual amino acid, deoxyhypusine. DHS protein levels were suppressed in transgenic plants by expressing the 3'-untranslated region of tomato DHS under regulation of the constitutive cauliflower mosaic virus promoter. Fruit from the transgenic plants ripened normally, but exhibited delayed postharvest softening and senescence that correlated with suppression of DHS protein levels. Northern-blot analysis indicated that all four gene family members of tomato eIF-5A are expressed in fruit, and that three are up-regulated in parallel with enhancement of DHS mRNA as the fruit begin to senesce and soften. Transgenic plants in which DHS was more strongly suppressed were male sterile, did not produce fruit, and had larger, thicker leaves with enhanced levels of chlorophyll. The activity of PSII was 2 to 3 times higher in these transgenic leaves than in corresponding leaves of wild-type plants, and there was also enhanced deposition of starch in the stems. The data collectively indicate that suppression of DHS has pleiotropic effects on growth and development of tomato. This may, in turn, reflect the fact that there is a single DHS gene in tomato and that its cognate protein is involved in the activation of four distinct isoforms of eIF-5A.

[Roles of intracellular calcium and monomeric G-proteins in regulating exocytosis of human neutrophils].

Neutrophils play a major role in host defense against microbial infection. There are some clues indicate that neutrophils may also play a role in the pathophysiology of the airway obstruction in chronic asthma. We studied the roles of intracellular calcium and GTP gamma S in the regulation of neutrophils exocytosis using pipette perfusion and membrane capacitance measurement technique in whole cell patch clamp configuration. The results showed that the membrane capacitance increase induced by calcium revealed a biphasic process. The first phase occurred when the calcium level was between 0.2-14 micromol/L with a plateau amplitude of 1.23 pF and a calcium EC50 of 1.1 micromol/L. This phase might correspond to the release of the tertiary granules. The second phase occurred when the calcium concentration was between 20-70 micromol/L with a plateau increment of 6.36 pF, the calcium EC50 being about 33 micromol/L. This phase might represent the release of the primary and secondary granules. Intracellular calcium also simultaneously increased the exocytotic rate and the eventual extent in neutrophils. On the other hand, GTP gamma S can increase the exocytotic rate in a dose-dependent manner but had no effect on the eventual extent of membrane capacitance increment (>6 pF) if the cell was stimulated for a long period (>20 min). GTP gamma S (ranging from 20 to 100 micromol/L) induced the neutrophils to release all four types of the granules at very low intracellular calcium level.

Pleiotropic effects of suppressing deoxyhypusine synthase expression in Arabidopsis thaliana.

A full-length cDNA clone encoding deoxyhypusine synthase (DHS) was isolated from a cDNA expression library prepared from senescing leaves of Arabidopsis thaliana. Southern blot analysis indicated that DHS is encoded by a single-copy gene in Arabidopsis. During leaf development, the abundance of DHS mRNA in the third pair of rosette leaves peaked at days 14 and 35 after emergence coincident with the initiation of bolting and the later stages of leaf senescence, respectively. These changes in DHS expression were paralleled by corresponding changes in transcript abundance for eIF-5A1, one of three isoforms of eIF-5A in Arabidopsis. Levels of DHS transcript also increased in detached leaves coincident with post-harvest senescence. DHS was suppressed in transgenic plants by introducing antisense full-length or 3'-untranslated Arabidopsis DHS cDNA under the regulation of the constitutive cauliflower mosaic virus (CaMV-35S) promoter. Plants expressing the antisense transgenes had reduced levels of leaf DHS protein and, depending on the level of DHS suppression, exhibited delayed natural leaf senescence, delayed bolting, increased rosette leaf and root biomass, and enhanced seed yield. Suppression of DHS also delayed premature leaf senescence induced by drought stress resulting in enhanced survival in comparison with wild-type plants. In addition, detached leaves from DHS-suppressed plants exhibited delayed post-harvest senescence. These pleiotropic effects of DHS suppression indicate that the protein plays a central role in plant development and senescence.