Potassium channel AKT1 is involved in the auxin-mediated root growth inhibition in Arabidopsis response to low K^+stress

The changes in external K^+ concentration affect plant root growth. However, the molecular mechanism for perceiving a K^+ signal to modulate root growth remains unknown. It is hypothesized that the K^+ channel AKT1 is involved in low K^+ sensing in the Arabidopsis root and subsequent regulation of root growth. Along with the decline of external K^+ concentration, the primary root growth of wild-type plants was gradually inhibited.However, the primary root of the akt1 mutant could still grow under low K^+ (LK) conditions. Application of NAA inhibited akt1 root growth, but promoted wild-type root growth under LK conditions. By using the Pro DR5:GFP and Pro PIN1:PIN1-GFP lines, we found that LK treatment reduced auxin accumulation in wild-type root tips by degrading PIN1 proteins, which did not occur in the akt1 mutant. The LK-induced PIN1 degradation may be due to the inhibition of vesicle trafficking of PIN1 proteins. In conclusion, our findings indicate that AKT1 is required for an Arabidopsis response to changes in external K^+ , and subsequent regulation of K^+ -dependent root growth by modulating PIN1 degradation and auxin redistribution in the root.

Inhibition of the growth and development of mosquito larvae of Culex quinquefasciatus(Diptera:Culicidae) treated with extract from leaves of Pseudocalymma alliaceum(Bignonaceae)

Objective:To determine larvicidal activity of the essential oil,hydrolat and botanical extracts derived from leaves ol Pseudocalymma alliaceum an mosquito larvae of Culex quinquefasciatus.Methods:Groups of twenty lanae were used in the larvicidal assays.The mortality,relative growth rate,the larval and pupal duration and viability was estimated.The essential oil was analyzed by solid phase microextraction using gas chromatography coupled to mass spectrometry.Results:Essential oil at 800 ppm showed larvicidal activity at 24 h with lethal values of LC_(50) and LC_(90) of 267.33 and 493.63 ppm.The hvdrolat at 20% and 10% on 2nd stage larvae showed 100%effectiveness after 24 h.The aqueous extract at 10% had a relative growth index of 0.58.while the ethanolic and methanolic extract obtained values of 0.76 and 0.70 and control reached 0.99.Larvae treated with 10% of methanol,ethanol and aqueous extract showed a reduction in larval duration of 5.00,2.20 and 4.35 days;ethanol extract at 1% provoke decrease of 2.40 days in the development and exhibited an increment of 3.30 days when treated with 0.01%.Aqueous,ethanol and methanol extracts at 10%reduced in 6.15,3.42 and 5.57 days pupal development.The main compounds were diallyl disulfide(50.05%),diallyl sulfide(11.77%) and disulfide di-2-propenyl(10.37%).Conclusions:The study demonstrated for the first time,the larvicidal activity of the essential oil and hydrolat of Pseudocalymma alliaceum:aqueous,ethanol and methanol extracts inhibited the normal growth and development of mosquito larvae,prolonging and delaying larval and pupal duration.

Sucrose Enhances Tyrosine-induced Inhibition of Growth in Arabidopsis Seedlings

Tyrosine (Tyr) and sucrose (Suc) play an important role in plant growth.However,the crosstalk between Tyr and Suc in regulating the plant growth has remained unclear.In this study,it was found that Suc is able to enhance Tyr-induced inhibition of growth in Arabidopsis seedlings.Both fresh weight and root length of Arabidopsis seedlings were significantly reduced when the medium was added with high concentrations (such as 0.5 or 1.0 mM)of Tyr whereas they were clearly increased with an addition of appropriate concentrations of Suc (such as 1 or 3%) in the medium,which suggested that the growth of Arabidopsis seedlings is inhibited by high concentrations of Tyr but promoted by appropriate concentrations of Suc.Interestingly,the inhibition of growth in Arabidopsis seedlings by 0.5 or 1.0 mM Tyr was significantly intensified once 1%or 3%of Suc was added in the medium.This study revealed a positive effect of Suc on the Tyr-induced inhibition of plant growth,and the results help us to further investigate the crosstalk of Suc and Tyr in the regulation of plant growth.

Inhibition of epidermal growth factor receptor signaling protects human malignant glioma cells from hypoxia - induced cell death

Epidermal growth factor receptor(EGFR)signaling has become an importanttarget for drug development becauseEGFR signaling enhances tumor cell proliferation,migration,and invasion and inhibits apoptosis.However,theresults of clinical trials using EGFR inhibitors in patients with solid tumors have been disappointing.Here,wereport a protective effect of the EGFR inhibitors AG1478 and PD153035 against cell death induced by acute hy-poxia,which contrasts with their proapoptotic effects under normoxia.Under hypoxic conditions,both agents re-

Effects of targeted-edited oncogenic insulin-like growth factor-1 receptor with specific-sgRNA on biological behaviors of Hep G2 cells

BACKGROUND Insulin-like growth factor-1 receptor(IGF-1R)is over-expressed in hepatocellular carcinoma(HCC).However,the relationship between IGF-1R activation and HCC progression remains unidentified.AIM To investigate the effects of editing IGF-1R on the biological features of HCC cells.METHODS Immunohistochemistry analyzed the expressions of IGF-1R and P-glyco protein(P-gp)in HCC tissues and their distal non-cancerous tissues(non-Ca).IGF-1R was edited with Crispr/Cas9 system,screened specific sg RNAs,and then transfected into Hep G2 cells.CCK-8,scratch wound test detected cell proliferation,migration,invasion and transwell assays,respectively.Alterations of IGF-1R and P-gp were confirmed by Western blotting.Alterations of anti-cancer drug IC_(50)values were analyzed at the cell level.RESULTS The positive rates of IGF-1R(93.6%,χ~2=63.947)or P-gp(88.2%,χ~2=58.448)were significantly higher(P<0.001)in the HCC group than those(36.6%in IGF-1R or 26.9%in P-gp)in the non-Ca group.They were positively correlated between high IGF-1R and P-gp expression,and they were associated with hepatitis B virus infection and vascular invasion of HCC.Abnormal expressions of circulating IGF-1R and P-gp were confirmed and associated with HCC progression.Biological feature alterations of HCC cells transfected with specific sg RNA showed IGF-1R expression down-regulation,cell proliferation inhibition,cell invasion or migration potential decreasing,and enhancing susceptibility of Hep G2 cells to anti-cancer drugs.CONCLUSION Edited oncogenic IGF-1R was useful to inhibit biological behaviors of Hep G2 cells.

Growth and inhibition of zinc anode dendrites in Zn-air batteries:Model and experiment

Zinc(Zn)-air batteries are widely used in secondary battery research owing to their high theoretical energy density,good electrochemical reversibility,stable discharge performance,and low cost of the anode active material Zn.However,the Zn anode also leads to many challenges,including dendrite growth,deformation,and hydrogen precipitation self-corrosion.In this context,Zn dendrite growth has a greater impact on the cycle lives.In this dissertation,a dendrite growth model for a Zn-air battery was established based on electrochemical phase field theory,and the effects of the charging time,anisotropy strength,and electrolyte temperature on the morphology and growth height of Zn dendrites were studied.A series of experiments was designed with different gradient influencing factors in subsequent experiments to verify the theoretical simulations,including elevated electrolyte temperatures,flowing electrolytes,and pulsed charging.The simulation results show that the growth of Zn dendrites is controlled mainly by diffusion and mass transfer processes,whereas the electrolyte temperature,flow rate,and interfacial energy anisotropy intensity are the main factors.The experimental results show that an optimal electrolyte temperature of 343.15 K,an optimal electrolyte flow rate of 40 ml·min^(-1),and an effective pulse charging mode.

Down-regulation of Notch-1 gene expression inhibits growth of TJ-905 glioblastoma

Objective To study the inhibitory effect of siRNA on glioblastoma (GBM) Notch-1 gene expression in addition to the growth of TJ-905 glioblastoma. Methods Three small interference RNAs (siRNAs) targeting Notch1 gene,named siRNA1,siRNA2,siRNA3,synthesized chemically in vitro with gene bank BLAST. TJ-905 cells were transfected twice with the siRNA by using Oligofectamine

Responses of phytoplankton and its satellite bacteria to exogenous ethanol

The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of satellite bacteria isolated from nonaxenic SSP cultures,and Escherichia coli were screened.Results indicate that ethanol could promote the growth and photo synthetic efficiency(F_(v)/F_(m))of S SP at 0.01%and the growth of satellite bacteria at 0.01%-1%.Nevertheless,ethanol inhibited the growth and F_(v)/F_(m)of SSP at 0.1%-1%,and killed bacteria and SSP at 10% concentration.Further investigation on a satellite bacterium(Mameliella alba)revealed that ethanol promotes growth by serving as a growth stimulant rather than a metabolic carbon source.The 16 S rRNA gene amplicon indicated that all nonaxenic S SP cultures harbor distinct satellite bacteria communities where the SSP culture of Skeletonema costatum,Phaeodactylum tricornutum,and Dunaliella bardawil were dominated by bacteria genera of Marivita(~80%),Dinoroseobacter(~47%),and Halomonas(~87%),respectively,indicating that every SSP cultures have their own distinct satellite bacterial community.The bacteria family Rhodobacteraceae was dominant in the two marine diatoms,whereas Halomonadaceae was dominant in the saline green microalga.Compared to their respective controls,the supply of 0.5% ethanol to SSP cultures promoted the growth of the satellite bacteria but did not cause a significant difference in species composition of satellite bacteria.Therefore,a low concentration of ethanol can promote the growth of bacteria in a non-selective way.This study enriched our knowledge about the effect of ethanol on aquatic microbes and provided a baseline for basic and applied biotechnological re search in the aquatic environment in the future.

In Situ Generation of Copper Nanoparticles in Heat-Treated Copper-Containing Masson’s Pine as a Preservative Process for Sawn Timber

Heat-treated wood has good dimensional stability,durability,and color,but its susceptibility to fungal growth affects its commercial value.In this study,lumber harvested from mature Masson’s pine(Pinus massoniana Lamb.)was vacuum impregnated with a basic copper salt solution(copper hydroxide,diethanolamine,and polyethylene glycol 200)prior to heat-treatment at 220℃ for 3 h.Antifungal properties,surface chemistry,crystal structure and sugar contents were tested,compared with heat treatment alone.The results showed that the samples treated by heating without copper salt treatment showed poor suppression of fungal growth,the copperimpregnated heat-treated wood suppressed(100%)the growth of Botryodiplodia theobromae Pat.,Aspergillus niger V.Tiegh.,Penicillium citrinum Thom,and Trichoderma viride Pers.The combined results of X-ray photoelectron spectroscopy,X-ray diffraction and sugars analysis suggested that fungal inhibition by the heat-treated copper-bearing Masson’s pine was mainly due to the reduction of the metal salt by PEG200 at high temperature to generate copper nanoparticles.In addition,the reduced sugar content of the treated timber,and hence the nutrient substrate for spoilage microbes,reduced in the presence of the metal salts at high-temperature.This study has demonstrated an effective method of increasing low-grade wood’s utility and commercial value.

Novel Mannich Bases of Benzimidazole Derivatives: An Antibacterial Study of Environmental Bacterial Strains

A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.

Antibacterial and Antifungal Activity of Organic and Peptidic Extracts of Ecuadorian Endophytic Fungi

Antibacterial and antifungal activities of 32 organic and 14 peptidic extracts obtained from twelve endophytic fungi of the Collection of Endophytes Quito-Catolica were tested against the pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli and Salmonella enteritidis, and against the fungal oomycete Pythium ultimum. It was observed that the extracts of Marasmiellus candidus (CEQCA-O1113), Xylaria laevis (CEQCA-O1399), Fusarium solani (CEQCA-O1393), Diaporthe helianthi (CEQCA-O1394) and Xylaria sp. (CEQCA-O1400) partially or totally inhibited the microorganisms tested. The extracts CEQCA-O1399.P1 and CEQCA-O1113.D1 showed fungistatic and fungicidal effects against P. ultimum, respectively. Six extracts strongly inhibited S. aureus, and E. coli was strongly inhibited by the extract CEQCA-O1113.E2. Based on a bioassay-guided approach, the extracts with strong bioactivity in the antibacterial assays by an agar diffusion method were also tested by a disk diffusion method, and the minimal inhibitory concentrations were determined by a microdilution assay. The most bioactive extract, CEQCA-O1113.D1, was also purified by high performance liquid chromatography. The extract recovered its initial bioactivity against S. aureus in two fractions after the purification. Overall, the results of this study highlight the potential of the fungal endophytes as producers of bioactive compounds.

The Wheat Pathogenesis Related Protein (TdPR1.2) Ensures Contrasting Behaviors to <i>E. coli</i>Transformant Cells under Stress Conditions

The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metabolism in response to biotic and abiotic stresses. The wheat TdPR1.2 has been previously isolated and characterized. Here we showed by bio-informatic analysis that TdPR1.2 contains six cysteine residues that are conserved between all PR-1 proteins tested. Using ScanProsite tool, we found that TdPR1.2 structure has a CRISP family signature 1 and 2 located at the C-terminal part of the protein. Those two domains are conserved in many identified PR1.2 proteins in plants. Moreover, SignalIP-5.0 analysis revealed that TdPR1.2 contains a putative signal peptide formed by 25 amino acids at the N-terminal extremity. The presence of this signal peptide suggested that the mature proteins will be secreted after the cleavage of the signal sequence. Further, we investigate the role of the TdPR1.2 proteins in the growth of Escherichia coli transformants cells under different abiotic stresses. Our results showed that the full-length form of TdPR1.2 enhanced tolerance of E. coli against salt and osmotic stress but not to KCl. Moreover, TdPR1.2 protein confers bacterial tolerance to heavy metals in solid and liquid mediums. Based on these results, we suggest that the TdPR1.2 protein could play an important role in response to abiotic stress conditions.

Progress in Use of Natural Products and Their Active Components against Helicobacter pylori

Helicobacter pylori is considered the main etiological agent of gastritis, ulcers, and gastric carcinoma. It colonizes human gastric mucosa quite efficiently. Fifty % of the world population is actually infected. Since H. pylori discovery in 1982, it is well known the sensitivity of several H. pylori strains to a number of antibiotics when these are assayed in vitro. However, eradication therapies with a single antibacterial agent have failed. Recently, triple, quadruple, sequential, concomitant and hybrid therapies which include antibiotics and a proton pump inhibitor show improved eradication rate and low side effects. However, new problems have emerged. Antimicrobial resistance to the common antibiotics used has become a problem in both developed and developing countries. In particular, H. pylori clarithromycin- and metronidazole-resistant strains are a major problem in countries where H. pylori is highly prevalent. Thus, the widespread use of antibiotics is not economically feasible and might increase difficulties in the treatment of H. pylori. At present, there are no vaccines available in the market. As an alternative, effective non-antibiotic compounds should be highly desirable since their use may be safer and suitable to eradicate H. pylori. The first step in this direction has been to study the effect of medicinal herbs and natural products, such as green tea, ginseng, garlic, propolis, and probiotics, then identify their active components such as polyphenols, antioxidants, purify them, and finally test them using in vitro and in vivo H. pylori growth assays. Some of them have been quite effective. The topics related to alternative therapies for H. pylori infections and current status of their use will be discussed in the present review.

Dobesilate for dry age-related macular degeneration

We have evaluated the effects of intravitreal dobesilate, a synthetic fibroblast growth factor inhibitor, in patients with dry age-related macular degeneration, an inflammatory-related retinal disease without available treatment up to date. 36 eyes from 36 patients with dry age-related macular degeneration were treated with a single intravitreal dobesilate injection. The end points were the improvement from baseline visual acuity and normalization of retinal histology at one month. Intravitreal dobesilate injection resulted in a significant improvement in functional and anatomical outcomes at one month after injection. Our results suggest that intravitreal dobesilate may increase the chance of visual acuity gain in dry age-related macular degeneration, even in cases with initial low vision. This study supports the findings of previously published case reports, regarding the short-term improvement in visual acuity by intravitreal dobesilate injection in different degenerative retinal diseases.

Mercury uptake and effects on growth in Jatropha curcas

The use of metal-accumulating plants for the phytoremediation of contaminated soils is gaining more attention. Mercury(Hg)-contaminated soils from historical gold mines represent a potential risk to human health and the environment. Therefore, Jatropha curcas plant, that has shown its tolerance to these environments, is a species of particular interest to implement phytoremediation techniques in gold mining sites. In this work, the behavior of J. curcas was assessed in different hydroponic cultures fortified with Hg at concentrations of 5, 10, 20, 40, and 80 μg Hg/mL(T5, T10, T20, T40 and T80, respectively). After exposure,plant growth, net photosynthesis, leaf area, and Hg accumulation were determined and variables such as net Hg uptake, effective Hg accumulation, translocation and bioaccumulation factors were calculated. Accumulation of Hg in root and leaf tissues increased with respect to the Hg concentrations in the hydroponic culture, with statistically significant differences(p < 0.05) among treatments. Moreover, Hg concentration in roots was 7 and 12-fold higher in average than in plant leaves and shoots, respectively. Many effects were found in the development of plants, especially related with loss of biomass and leaf area,with significant growth inhibition related to control values(> 50% with treatment T5).Moreover, percentage of inhibition was even higher(> 60%) with same treatment for net photosynthesis. Finally, it should be highlighted that for T40 and T80 treatments, plant growth and photosynthesis were almost completely depleted(88%–95%).

Angiotensin Ⅱ type 1 receptor antagonist inhibits growth of human bladder cancer xenograft

AngiotensinⅡis known as a key biologically active peptide in rennin-angiotensin system, which regulates blood pressure, and angiotensinⅡtype 1 receptor (AT1R) antagonists are widely used as antihypertensive drugs. Since several human cancers have been reported to express AT1R, it is worthwhile to test whether AT1R antagonists

Targeted suppression of miRNA-21 inhibit K562 cells growth through PTEN-PI3K/AKT signaling pathway

Objective To investigate the K562 cells biological function and related molecular changes in PTEN-PI3K/AKT signaling pathway of leukemia K562 cells by inhibiting the miRNA-21 expression to explore its pathogenesis of leukemia.Methods The chemical synthetic miRNA-

Auxin signaling:Research advances over the past 30 years

Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transport,signaling,and metabolism have largely been unlocked.Due to the rapid development of new technologies,new methods,and new genetic materials,the study of auxin has entered the fast lane over the past 30 years.Here,we highlight advances in understanding auxin signaling,including auxin perception,rapid auxin responses,TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes(TIR1/AFBs)-mediated transcriptional and non-transcriptional branches,and the epigenetic regulation of auxin signaling.We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition,we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling,which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development.The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field,leading to an increasingly deeper,more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.

Crystal structure of human Gadd45 reveals an active dimer

The human Gadd45 protein family plays critical roles in DNA repair,negative growth control,genomic stability,cell cycle checkpoints and apoptosis.Here we report the crystal structure of human Gadd45,revealing a unique dimer formed via a bundle of four parallel helices,involving the most conserved residues among the Gadd45 isoforms.Mutational analysis of human Gadd45 identified a conserved,highly acidic patch in the central region of the dimer for interaction with the proliferating cell nuclear antigen(PCNA),p21 and cdc2,suggesting that the parallel dimer is the active form for the interaction.Cellular assays indicate that:(1)dimerization of Gadd45 is necessary for apoptosis as well as growth inhibition,and that cell growth inhibition is caused by both cell cycle arrest and apoptosis;(2)a conserved and highly acidic patch on the dimer surface,including the important residues Glu87 and Asp89,is a putative interface for binding proteins related to the cell cycle,DNA repair and apoptosis.These results reveal the mechanism of self-association by Gadd45 proteins and the importance of this self-association for their biological function.