Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most asp...Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most aspects of the jasmonate （JA） signaling pathway in Arabidopsis. MYC2 coordinates JA-mediated defense responses by antagonistically regulating two different branches of the JA signaling pathway that determine resistance to pests and pathogens, respectively. MYC2 is required for induced systemic resistance （ISR） triggered by beneficial soil microbes while MYC2 function is targeted by pathogens during effector-mediated suppression of innate immunity in roots. Another notable function of MYC2 is the regulation of crosstalk between the signaling pathways of JA and those of other phytohormones such as abscisic acid （ABA）, salicylic acid （SA）, gibberellins （GAs）, and auxin （IAA）. MYC2 also regulates interactions between JA signaling and light, phytochrome signaling, and the circadian clock, MYC2 is involved in JA-regulated plant development, lateral and adventitious root formation, flowering time, and shade avoidance syndrome. Related bHLH TFs MYC3 and MYC4 also regulate both overlapping and distinct MYC2-regulated functions in Arabidopsis while MYC2 orthologs act as ＇master switches＇ that regulate JA-mediated biosynthesis of secondary metabolites. Here, we briefly review recent studies that revealed mechanistic new insights into the mode of action of this versatile TF.展开更多
ELONGATED HYPOCOTYL5 （HY5）, a member of the bZlP transcription factor family, inhibits hypocotyl growth and lateral root development, and promotes pigment accumulation in a light-dependent manner in Arabidopsis. Rec...ELONGATED HYPOCOTYL5 （HY5）, a member of the bZlP transcription factor family, inhibits hypocotyl growth and lateral root development, and promotes pigment accumulation in a light-dependent manner in Arabidopsis. Recent research on its role in different processes such as hormone, nutrient, abiotlc stress （abscisic acid, salt, cold）, and reactive oxygen species signaling pathways clearly places HY5 at the center of a transcriptional network hub. HY5 regulates the transcription of a large number of genes by directly binding to cis-regulatory elements. Recently, HY5 has also been shown to activate its own expression under beth visible and UV-B light. Moreover, HY5 acts as a signal that moves from shoot to root to promote nitrate uptake and root growth. Here, we review recent advances on HY5 research in diverse aspects of plant development and highlight still open questions that need to be addressed in the near future for a complete understanding of its function in plant signaling and beyond.展开更多
Indole-3-acetic acid （IAA）, the main naturally occurring auxin, is essential for almost every aspect of plant growth and development. However, only recently have studies finally established the first complete auxin ...Indole-3-acetic acid （IAA）, the main naturally occurring auxin, is essential for almost every aspect of plant growth and development. However, only recently have studies finally established the first complete auxin biosynthesis pathway that converts tryptophan （Trp） to IAA in plants. Trp is first converted to indole-3-pyruvate （IPA） by the TAA family of amino transferases and subsequently IAA is produced from IPA by the YUC family of flavin monooxygenases. The two- step conversion of Trp to IAA is the main auxin biosynthesis pathway that plays an essential role in many developmental processes.展开更多
The plasma membrane （PM） H^＋-ATPase is an important ion pump in the plant cell membrane. By extruding protons from the cell and generating a membrane potential, this pump energizes the PM, which is a prerequisite f...The plasma membrane （PM） H^＋-ATPase is an important ion pump in the plant cell membrane. By extruding protons from the cell and generating a membrane potential, this pump energizes the PM, which is a prerequisite for growth. Modification of the autoinhibitory terminal domains activates PM H^＋-ATPase activity, and on this basis it has been hypothesized that these regulatory termini are targets for physiological factors that activate or inhibit proton pumping. In this review, we focus on the posttranslational regulation of the PM H＋-ATPase and place regulation of the pump in an evolutionary and physiological context. The emerging picture is that multiple signals regulating plant growth interfere with the posttranslational regulation of the PM H^＋-ATPase.展开更多
Hepatocellular carcinoma(HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. There have been great improvements in the diagnosis and treatment of HCC in recent years...Hepatocellular carcinoma(HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. There have been great improvements in the diagnosis and treatment of HCC in recent years, but the problems, including difficult diagnosis at early stage, quick progression, and poor prognosis remain unsolved. Surgical resection is the mainstay of the treatment for HCC. However, 70%-80% of HCC patients are diagnosed at an advanced stage when most are ineligible for potentially curative therapies such as surgical resection and liver transplantation. In recent years, non-surgical management for unrespectable HCC, such as percutaneous ethanol injection, percutaneous microwave coagulation therapy, percutaneous radiofrequency ablation, transcatheter arterial chemoembolization, radiotherapy, chemotherapy, biotherapy, and hormonal therapy have been developed. These therapeutic options, either alone or in combination, have been shown to control tumor growth, prolong survival time, and improve quality of life to some extent. This review covers the current status and progress of non-surgical management for HCC.展开更多
Aim: To study the apoptotic rate (AR) and the androgen and estrogen milieu in the proximal and distal ductal sys-tems of prostate, in order to help exploring the effects of these factors on prostatic growth and the pa...Aim: To study the apoptotic rate (AR) and the androgen and estrogen milieu in the proximal and distal ductal sys-tems of prostate, in order to help exploring the effects of these factors on prostatic growth and the pathogenesis of be-nign prostatic hypertrophy (BPH). Methods: The proximal and distal ends of the ductal system were incised from20 normal prostate as well as the hypertrophic prostate tissue from 20 patients with BPH. The AR was determined bythe DNA end-labeling method and dihydrotestosterone (DHT) and estrodiol (E_2), by radioimmunoassay. Results:There was no significant difference in DHT and E_2 density between the proximal and distal ends of the ductal systems innormal prostate. E_2 appeared to be higher in BPH than in normal prostatic tissues, but the difference was statistically in-significant. In normal prostatic tissue, the AR was significantly higher in the distal than in the proximal ends of theductal system (P<0.05), while the AR of the proximal ends was significantly higher (P <0.01) than that in theBPH tissue. No significant correlation was noted between the DHT and E_2 density and the AR both in the normalprostate and BPH tissues. Conclusion: The paper is the first time describing a difference in AR in different regionsof the ductal system of normal prostate, while the hormonal milieu is similar, indicating a functional inhomogeneity ofthese regions. A low AR in the proximal duct, where BPH originates, and an even lower AR in the BPH tissue, sug-gesting the participation of apoptosis in the BPH pathogenesis.展开更多
目的:观察间歇性内分泌治疗在不同分期及分级的前列腺癌患者中的效果,并分析影响疗效的可能相关因素。方法:对45例不同分期及分级的前列腺癌患者进行间歇性内分泌治疗:首先行激素诱导治疗即药物去势和/或抗雄激素治疗,停止治疗的时机为...目的:观察间歇性内分泌治疗在不同分期及分级的前列腺癌患者中的效果,并分析影响疗效的可能相关因素。方法:对45例不同分期及分级的前列腺癌患者进行间歇性内分泌治疗:首先行激素诱导治疗即药物去势和/或抗雄激素治疗,停止治疗的时机为保持前列腺特异抗原(prostate specific antigen,PSA)≤0.2μg/L(ng/mL)水平持续3个月,以后根据每月PSA的检测结果决定是否再行内分泌治疗。随访观察患者治疗的轮数和治疗期及间歇期的时间。根据治疗效果将上述患者分为治疗耐受较好和治疗耐受较差两组,单因素分析比较两组患者在人口统计学、临床、生化、影像、病理等方面的差异,并使用非条件Logistic回归分析探讨影响治疗耐受的独立相关因素。结果:平均随访时间为40.7±13.4个月。45例患者中,41名患者进入第2轮治疗,其中8例患者在第2轮治疗期间进展为雄激素非依赖性前列腺癌;8例中7例患者均为T3-4M0或M1期且Gleason评分≥8分。16名患者进入第3轮治疗,其中有14名分期为Ⅲ期以内,有13名患者Gleason评分≤7分。第1到第4周期平均间歇期(分别占第1到第4疗程时间的百分比)分别为8.7±5.4个月(47.1%),8.4±4.9个月(49.3%),7.0±3.4个月(43.7%),3.7±0.6个月(42.5%)。5例患者在治疗过程中出现骨转移,目前没有患者死亡。按照评价标准将患者分为治疗耐受较好(n=16)与治疗耐受较差两组(n=29),与治疗耐受较差的患者相比,治疗耐受较好的患者Gleason评分较低(P=0.002),PSA值较低(P=0.053),Ⅳ期患者较少(P=0.001)。相反,年龄、有无骨转移、淋巴结转移及有无复发等差异均无统计学意义。非条件Logistic回归分析显示Ⅳ期患者所占比例是唯一影响治疗的独立相关因素(OR=12.113,95%CI1.330～110.312,P=0.027)。结论:能坚持较多治疗周期的患者多为肿瘤分化较好的Ⅲ期及以内的病患,而较快进展为激素非依赖性的患者多为�展开更多
To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of t...To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.展开更多
Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes de...Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes death of this potential tree-species within a few months. Vegetative propagation could avoid the die-back disease. Thirty mother trees of different age-groups of D. sissoo were selected for evaluating the rooting behaviour of branch cuttings from D. sissoo as influenced by auxins （IAA or IBA at 100, 200, 500 mg·L^-1）, ages of mother trees （10, 4 and 2 years old） and different environment conditions, i.e., different mediums （soil and sand） or light conditions （in shade and open condition）. The results show that application of IAA and IBA induced more numbers of cuttings （collected from 10-year-old mother trees） to root compared to control. Branch cuttings of D. sissoo collected from 10-year-old mother trees and planted in soil bed in open conditions had 100.0% of cuttings to root in IAA （100 mg·L^-1） and IBA （200 mg·L^-1） treatments. Both rooting medium （Soil and sand） influenced significantly （p〈0.05） on rooting response of branch cuttings. Soil medium was found to achieve maximum no. of branch cuttings to root, compared to sand medium.展开更多
Strigolactones （SLs）, or their metabolites, were recently identified as endogenous inhibitors of shoot branch- ing. However, certain key features and dynamics of SL action remained to be physiologically characterize...Strigolactones （SLs）, or their metabolites, were recently identified as endogenous inhibitors of shoot branch- ing. However, certain key features and dynamics of SL action remained to be physiologically characterized. Here we show that successive direct application of SL to axillary buds at every node along the stem can fully inhibit branching. The SL inhibition of early outgrowth did not require inhibitory signals from other growing buds or the shoot tip. In add- ition to this very early or initial suppression of outgrowth, we also found SL to be effective, up to a point, at moderating the continuing growth of axillary branches. The effectiveness of SL at affecting bud and branch growth correlated with the ability of SL to regulate expression of PsBRC1. PsBRC1 is a transcription factor that is expressed strongly in axillary buds and is required for SL inhibition of shoot branching. Consistent with a dynamic role of the hormone, SL inhibition of bud growth did not prevent buds from later responding to a decapitation treatment, even though SL treatment immediately after decapitation inhibits the outgrowth response. Also, as expected from the hypothesized branching control network in plants, treatment of exogenous SL caused feedback down-regulation of SL biosynthesis genes within 2 h. Altogether, these results reveal new insights into the dynamics of SL function and support the premise that SLs or SL-derived metabolites function dynamically as a shoot branching hormone and that they act directly in axillary buds.展开更多
AUXIN BINDING PROTEIN 1 （ABP1） has long been proposed as an auxin receptor to regulate cell expansion. The embryo lethality of ABP1-null mutants demonstrates its fundamental role in plant development, but also hinde...AUXIN BINDING PROTEIN 1 （ABP1） has long been proposed as an auxin receptor to regulate cell expansion. The embryo lethality of ABP1-null mutants demonstrates its fundamental role in plant development, but also hinders investigation of its involvement in post-embryonic processes and its mode of action. By taking advantage of weak alleles and inducible systems, several recent studies have revealed a role for ABP1 in organ development, cell polarization, and shape formation. In addition to its role in the regulation of auxin-induced gene expression, ABP1 has now been shown to modulate non-transcriptional auxin responses. ABP1 is required for activating two antagonizing ROP GTPase signaling pathways involved in cytoskeletal reorganization and cell shape formation, and participates in the regulation of clathrinmediated endocytosis to subsequently affect PIN protein distribution. These exciting discoveries provide indisputable evidence for the auxin-induced signaling pathways that are downstream of ABP1 function, and suggest intriguing mechanisms for ABPl-mediated polar cell expansion and spatial coordination in response to auxin.展开更多
Interleukin-6(IL-6)is a pleiotropic cytokine involved in prostate regulation and in prostate cancer(PC)development/progression.IL-6 acts as a paracrine and autocrine growth stimulator in benign and tumor prostate cell...Interleukin-6(IL-6)is a pleiotropic cytokine involved in prostate regulation and in prostate cancer(PC)development/progression.IL-6 acts as a paracrine and autocrine growth stimulator in benign and tumor prostate cells.The levels of IL-6 and respective receptors are increased during prostate carcinogenesis and tumor progression.Several studies reported that increased serum and plasma IL-6 and soluble interleukin-6 receptor levels are associated with aggressiveness of the disease and are associated with a poor prognosis in PC patients.In PC treatment,patients diagnosed with advanced stages are frequently submitted to hormonal castration,although most patients will eventually fail this therapy and die from recurrent castration-resistant prostate cancer(CRPC).Therefore,it is important to understand the mechanisms involved in CRPC.Several pathways have been proposed to be involved in CRPC development,and their understanding will improve the way to more effective therapies.In fact,the prostate is known to be dependent,not exclusively,on androgens,but also on growth factors and cytokines.The signaling pathway mediated by IL-6 may be an alternative pathway in the CRPC phenotype acquisition and cancer progression,under androgen deprivation conditions.The principal goal of this review is to evaluate the role of IL-6 pathway signaling in human PC development and progression and discuss the interaction of this pathway with the androgen recepto pathway.Furthermore,we intend to evaluate the inclusion of IL-6 and its receptor levels as a putative new class of tumor biomarkers.The IL-6/IL-6R signaling pathway may be included as a putative molecular marker for aggressiveness in PC and it may be able to maintain tumor growth through the AR pathway under androgen-deprivation conditions.The importance of the IL-6/IL-6R pathway in regulation of PC cells makes it a good candidate for targeted therapy.展开更多
Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in plant developmental biology. Auxin, cytokinin, and ethylene are three important hormones that ...Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in plant developmental biology. Auxin, cytokinin, and ethylene are three important hormones that regulate many aspects of plant development. This review critically evaluates the crosstalk between the three hormones in Arabidopsis root development. We integrate a variety of experimental data into a crosstalk network, which reveals multiple layers of complexity in auxin, cytokinin, and ethylene crosstalk. In particular, data integration reveals an additional, largely overlooked link between the ethylene and cytokinin pathways, which acts through a phosphorelay mechanism. This proposed link addresses outstanding questions on whether ethylene application promotes or inhibits receptor kinase activity of the ethylene receptors. Elucidating the complexity in auxin, cytokinin, and ethylene crosstalk requires a combined experimental and systems modeling approach. We evaluate important modeling efforts for establishing how crosstalk between auxin, cytokinin, and ethylene regulates patterning in root develop- ment. We discuss how a novel methodology that iteratively combines experiments with systems modeling analysis is essential for elucidating the complexity in crosstalk of auxin, cytokinin, and ethylene in root development. Finally, we discuss the future challenges from a combined experimental and modeling perspective.展开更多
A new method of long-term culture of cytotrophoblast cells in serum-free medium has been developed. Cytotrophoblast cells were isolated with cold trypsin and purified by unit gravity sedimentation through BSA density ...A new method of long-term culture of cytotrophoblast cells in serum-free medium has been developed. Cytotrophoblast cells were isolated with cold trypsin and purified by unit gravity sedimentation through BSA density gradients. The cells were cultured in the FD medium with supplement of EGF, insulin, transferrin and sodium selenite. They could survive over three weeks. The results showed that both EGF and insulin stimulated hCG and progesterone secretion and that sodium selenite elevated hCG output but not progesterone secretion. Transferrin produced synergistic effect with EGF and insulin on hCG and progesterone secretion but it was ineffective when used alone. This study demonstrates that the four growth factors mentioned above are essential for the survival of cytotrophoblast cells in vitro. It is therefore suggested that EGF, insulin and selenium may possibly be involved in the regulation of hCG and progesterone secretion in the human placenta.展开更多
Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechani...Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf morphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules, play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis, several fundamental aspects of leaf morphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled. Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.展开更多
Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regu- lated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosy...Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regu- lated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosynthesis, impacts 1-aminocyclopropane 1-carboxylate synthase （ACS） protein stability via the complex interplay of specific factors. Here, we show that the Arabidopsis thaliana protein phosphatase type 2C, ABI1, a negative regulator of abscisic acid signaling, is involved in the regulation of ethylene biosynthesis under oxidative stress conditions. We found that ABI1 interacts with ACS6 and dephosphorylates its C-terminal fragment, a target of the stress-responsive mitogen-activated protein kinase, MPK6. In addition, ABI1 controls MPK6 activity directly and by this means also affects the ACS6 phosphorylation level. Consistently with this, ozone-induced ethylene production was significantly higher in an ABI1 knockout strain （abiltd） than in wild-type plants. Importantly, an increase in stress-induced ethylene production in the abiltd mutant was compen- sated by a higher ascorbate redox state and elevated antioxidant activities. Overall, the results of this study provide evi- dence that ABI1 restricts ethylene synthesis by affecting the activity of ACS6. The ABI1 contribution to stress phenotype underpins its role in the interplay between the abscisic acid （ABA） and ethylene signaling pathways.展开更多
Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholip...Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholipase A （pPLA） genes AtPLAIVA, AtPLAIVB, and AtPLAIVC and their corresponding proteins. Loss-of-function mutants reveal roles for these pPLAs in roots during normal development and under phosphate deprivation. AtPLAIVA is expressed strongly and exclusively in roots and AtplalVA-null mutants have reduced lateral root development, characteristic of an impaired auxin response. By contrast, AtPLAIVB is expressed weakly in roots, cotyledons, and leaves but is transcriptionally induced by auxin, although AtplalVB mutants develop normally. AtPLAIVC is expressed in the floral gynaecium and is induced by abscisic acid （ABA） or phosphate deficiency in roots. While an AtplalVC-1 loss-of-function mutant displays ABA respon- siveness, it exhibits an impaired response to phosphate deficiency during root development. Recombinant AtPLA proteins hydrolyze preferentially galactolipids and, less efficiently, phospholipids, although these enzymes are not localized in chloroplasts. We find that AtPLAIVA and AtPLAIVB are phosphorylated by calcium-dependent protein kinases in vitro and this enhances their activities on phosphatidylcholine but not on phosphatidylglycerol. Taken together, the data reveal novel functions of pPLAs in root development with individual roles at the interface between phosphate deficiency and auxin signaling.展开更多
文摘Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most aspects of the jasmonate （JA） signaling pathway in Arabidopsis. MYC2 coordinates JA-mediated defense responses by antagonistically regulating two different branches of the JA signaling pathway that determine resistance to pests and pathogens, respectively. MYC2 is required for induced systemic resistance （ISR） triggered by beneficial soil microbes while MYC2 function is targeted by pathogens during effector-mediated suppression of innate immunity in roots. Another notable function of MYC2 is the regulation of crosstalk between the signaling pathways of JA and those of other phytohormones such as abscisic acid （ABA）, salicylic acid （SA）, gibberellins （GAs）, and auxin （IAA）. MYC2 also regulates interactions between JA signaling and light, phytochrome signaling, and the circadian clock, MYC2 is involved in JA-regulated plant development, lateral and adventitious root formation, flowering time, and shade avoidance syndrome. Related bHLH TFs MYC3 and MYC4 also regulate both overlapping and distinct MYC2-regulated functions in Arabidopsis while MYC2 orthologs act as ＇master switches＇ that regulate JA-mediated biosynthesis of secondary metabolites. Here, we briefly review recent studies that revealed mechanistic new insights into the mode of action of this versatile TF.
文摘ELONGATED HYPOCOTYL5 （HY5）, a member of the bZlP transcription factor family, inhibits hypocotyl growth and lateral root development, and promotes pigment accumulation in a light-dependent manner in Arabidopsis. Recent research on its role in different processes such as hormone, nutrient, abiotlc stress （abscisic acid, salt, cold）, and reactive oxygen species signaling pathways clearly places HY5 at the center of a transcriptional network hub. HY5 regulates the transcription of a large number of genes by directly binding to cis-regulatory elements. Recently, HY5 has also been shown to activate its own expression under beth visible and UV-B light. Moreover, HY5 acts as a signal that moves from shoot to root to promote nitrate uptake and root growth. Here, we review recent advances on HY5 research in diverse aspects of plant development and highlight still open questions that need to be addressed in the near future for a complete understanding of its function in plant signaling and beyond.
文摘Indole-3-acetic acid （IAA）, the main naturally occurring auxin, is essential for almost every aspect of plant growth and development. However, only recently have studies finally established the first complete auxin biosynthesis pathway that converts tryptophan （Trp） to IAA in plants. Trp is first converted to indole-3-pyruvate （IPA） by the TAA family of amino transferases and subsequently IAA is produced from IPA by the YUC family of flavin monooxygenases. The two- step conversion of Trp to IAA is the main auxin biosynthesis pathway that plays an essential role in many developmental processes.
文摘The plasma membrane （PM） H^＋-ATPase is an important ion pump in the plant cell membrane. By extruding protons from the cell and generating a membrane potential, this pump energizes the PM, which is a prerequisite for growth. Modification of the autoinhibitory terminal domains activates PM H^＋-ATPase activity, and on this basis it has been hypothesized that these regulatory termini are targets for physiological factors that activate or inhibit proton pumping. In this review, we focus on the posttranslational regulation of the PM H＋-ATPase and place regulation of the pump in an evolutionary and physiological context. The emerging picture is that multiple signals regulating plant growth interfere with the posttranslational regulation of the PM H^＋-ATPase.
文摘Hepatocellular carcinoma(HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. There have been great improvements in the diagnosis and treatment of HCC in recent years, but the problems, including difficult diagnosis at early stage, quick progression, and poor prognosis remain unsolved. Surgical resection is the mainstay of the treatment for HCC. However, 70%-80% of HCC patients are diagnosed at an advanced stage when most are ineligible for potentially curative therapies such as surgical resection and liver transplantation. In recent years, non-surgical management for unrespectable HCC, such as percutaneous ethanol injection, percutaneous microwave coagulation therapy, percutaneous radiofrequency ablation, transcatheter arterial chemoembolization, radiotherapy, chemotherapy, biotherapy, and hormonal therapy have been developed. These therapeutic options, either alone or in combination, have been shown to control tumor growth, prolong survival time, and improve quality of life to some extent. This review covers the current status and progress of non-surgical management for HCC.
文摘Aim: To study the apoptotic rate (AR) and the androgen and estrogen milieu in the proximal and distal ductal sys-tems of prostate, in order to help exploring the effects of these factors on prostatic growth and the pathogenesis of be-nign prostatic hypertrophy (BPH). Methods: The proximal and distal ends of the ductal system were incised from20 normal prostate as well as the hypertrophic prostate tissue from 20 patients with BPH. The AR was determined bythe DNA end-labeling method and dihydrotestosterone (DHT) and estrodiol (E_2), by radioimmunoassay. Results:There was no significant difference in DHT and E_2 density between the proximal and distal ends of the ductal systems innormal prostate. E_2 appeared to be higher in BPH than in normal prostatic tissues, but the difference was statistically in-significant. In normal prostatic tissue, the AR was significantly higher in the distal than in the proximal ends of theductal system (P<0.05), while the AR of the proximal ends was significantly higher (P <0.01) than that in theBPH tissue. No significant correlation was noted between the DHT and E_2 density and the AR both in the normalprostate and BPH tissues. Conclusion: The paper is the first time describing a difference in AR in different regionsof the ductal system of normal prostate, while the hormonal milieu is similar, indicating a functional inhomogeneity ofthese regions. A low AR in the proximal duct, where BPH originates, and an even lower AR in the BPH tissue, sug-gesting the participation of apoptosis in the BPH pathogenesis.
文摘目的:观察间歇性内分泌治疗在不同分期及分级的前列腺癌患者中的效果,并分析影响疗效的可能相关因素。方法:对45例不同分期及分级的前列腺癌患者进行间歇性内分泌治疗:首先行激素诱导治疗即药物去势和/或抗雄激素治疗,停止治疗的时机为保持前列腺特异抗原(prostate specific antigen,PSA)≤0.2μg/L(ng/mL)水平持续3个月,以后根据每月PSA的检测结果决定是否再行内分泌治疗。随访观察患者治疗的轮数和治疗期及间歇期的时间。根据治疗效果将上述患者分为治疗耐受较好和治疗耐受较差两组,单因素分析比较两组患者在人口统计学、临床、生化、影像、病理等方面的差异,并使用非条件Logistic回归分析探讨影响治疗耐受的独立相关因素。结果:平均随访时间为40.7±13.4个月。45例患者中,41名患者进入第2轮治疗,其中8例患者在第2轮治疗期间进展为雄激素非依赖性前列腺癌;8例中7例患者均为T3-4M0或M1期且Gleason评分≥8分。16名患者进入第3轮治疗,其中有14名分期为Ⅲ期以内,有13名患者Gleason评分≤7分。第1到第4周期平均间歇期(分别占第1到第4疗程时间的百分比)分别为8.7±5.4个月(47.1%),8.4±4.9个月(49.3%),7.0±3.4个月(43.7%),3.7±0.6个月(42.5%)。5例患者在治疗过程中出现骨转移,目前没有患者死亡。按照评价标准将患者分为治疗耐受较好(n=16)与治疗耐受较差两组(n=29),与治疗耐受较差的患者相比,治疗耐受较好的患者Gleason评分较低(P=0.002),PSA值较低(P=0.053),Ⅳ期患者较少(P=0.001)。相反,年龄、有无骨转移、淋巴结转移及有无复发等差异均无统计学意义。非条件Logistic回归分析显示Ⅳ期患者所占比例是唯一影响治疗的独立相关因素(OR=12.113,95%CI1.330～110.312,P=0.027)。结论:能坚持较多治疗周期的患者多为肿瘤分化较好的Ⅲ期及以内的病患,而较快进展为激素非依赖性的患者多为�
文摘To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.
基金supported by Indian Council ofForestry Research and Education (ICFRE), Dehradun, 248 006, Uttarakhand, India
文摘Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes death of this potential tree-species within a few months. Vegetative propagation could avoid the die-back disease. Thirty mother trees of different age-groups of D. sissoo were selected for evaluating the rooting behaviour of branch cuttings from D. sissoo as influenced by auxins （IAA or IBA at 100, 200, 500 mg·L^-1）, ages of mother trees （10, 4 and 2 years old） and different environment conditions, i.e., different mediums （soil and sand） or light conditions （in shade and open condition）. The results show that application of IAA and IBA induced more numbers of cuttings （collected from 10-year-old mother trees） to root compared to control. Branch cuttings of D. sissoo collected from 10-year-old mother trees and planted in soil bed in open conditions had 100.0% of cuttings to root in IAA （100 mg·L^-1） and IBA （200 mg·L^-1） treatments. Both rooting medium （Soil and sand） influenced significantly （p〈0.05） on rooting response of branch cuttings. Soil medium was found to achieve maximum no. of branch cuttings to root, compared to sand medium.
文摘Strigolactones （SLs）, or their metabolites, were recently identified as endogenous inhibitors of shoot branch- ing. However, certain key features and dynamics of SL action remained to be physiologically characterized. Here we show that successive direct application of SL to axillary buds at every node along the stem can fully inhibit branching. The SL inhibition of early outgrowth did not require inhibitory signals from other growing buds or the shoot tip. In add- ition to this very early or initial suppression of outgrowth, we also found SL to be effective, up to a point, at moderating the continuing growth of axillary branches. The effectiveness of SL at affecting bud and branch growth correlated with the ability of SL to regulate expression of PsBRC1. PsBRC1 is a transcription factor that is expressed strongly in axillary buds and is required for SL inhibition of shoot branching. Consistent with a dynamic role of the hormone, SL inhibition of bud growth did not prevent buds from later responding to a decapitation treatment, even though SL treatment immediately after decapitation inhibits the outgrowth response. Also, as expected from the hypothesized branching control network in plants, treatment of exogenous SL caused feedback down-regulation of SL biosynthesis genes within 2 h. Altogether, these results reveal new insights into the dynamics of SL function and support the premise that SLs or SL-derived metabolites function dynamically as a shoot branching hormone and that they act directly in axillary buds.
文摘AUXIN BINDING PROTEIN 1 （ABP1） has long been proposed as an auxin receptor to regulate cell expansion. The embryo lethality of ABP1-null mutants demonstrates its fundamental role in plant development, but also hinders investigation of its involvement in post-embryonic processes and its mode of action. By taking advantage of weak alleles and inducible systems, several recent studies have revealed a role for ABP1 in organ development, cell polarization, and shape formation. In addition to its role in the regulation of auxin-induced gene expression, ABP1 has now been shown to modulate non-transcriptional auxin responses. ABP1 is required for activating two antagonizing ROP GTPase signaling pathways involved in cytoskeletal reorganization and cell shape formation, and participates in the regulation of clathrinmediated endocytosis to subsequently affect PIN protein distribution. These exciting discoveries provide indisputable evidence for the auxin-induced signaling pathways that are downstream of ABP1 function, and suggest intriguing mechanisms for ABPl-mediated polar cell expansion and spatial coordination in response to auxin.
文摘Interleukin-6(IL-6)is a pleiotropic cytokine involved in prostate regulation and in prostate cancer(PC)development/progression.IL-6 acts as a paracrine and autocrine growth stimulator in benign and tumor prostate cells.The levels of IL-6 and respective receptors are increased during prostate carcinogenesis and tumor progression.Several studies reported that increased serum and plasma IL-6 and soluble interleukin-6 receptor levels are associated with aggressiveness of the disease and are associated with a poor prognosis in PC patients.In PC treatment,patients diagnosed with advanced stages are frequently submitted to hormonal castration,although most patients will eventually fail this therapy and die from recurrent castration-resistant prostate cancer(CRPC).Therefore,it is important to understand the mechanisms involved in CRPC.Several pathways have been proposed to be involved in CRPC development,and their understanding will improve the way to more effective therapies.In fact,the prostate is known to be dependent,not exclusively,on androgens,but also on growth factors and cytokines.The signaling pathway mediated by IL-6 may be an alternative pathway in the CRPC phenotype acquisition and cancer progression,under androgen deprivation conditions.The principal goal of this review is to evaluate the role of IL-6 pathway signaling in human PC development and progression and discuss the interaction of this pathway with the androgen recepto pathway.Furthermore,we intend to evaluate the inclusion of IL-6 and its receptor levels as a putative new class of tumor biomarkers.The IL-6/IL-6R signaling pathway may be included as a putative molecular marker for aggressiveness in PC and it may be able to maintain tumor growth through the AR pathway under androgen-deprivation conditions.The importance of the IL-6/IL-6R pathway in regulation of PC cells makes it a good candidate for targeted therapy.
文摘Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in plant developmental biology. Auxin, cytokinin, and ethylene are three important hormones that regulate many aspects of plant development. This review critically evaluates the crosstalk between the three hormones in Arabidopsis root development. We integrate a variety of experimental data into a crosstalk network, which reveals multiple layers of complexity in auxin, cytokinin, and ethylene crosstalk. In particular, data integration reveals an additional, largely overlooked link between the ethylene and cytokinin pathways, which acts through a phosphorelay mechanism. This proposed link addresses outstanding questions on whether ethylene application promotes or inhibits receptor kinase activity of the ethylene receptors. Elucidating the complexity in auxin, cytokinin, and ethylene crosstalk requires a combined experimental and systems modeling approach. We evaluate important modeling efforts for establishing how crosstalk between auxin, cytokinin, and ethylene regulates patterning in root develop- ment. We discuss how a novel methodology that iteratively combines experiments with systems modeling analysis is essential for elucidating the complexity in crosstalk of auxin, cytokinin, and ethylene in root development. Finally, we discuss the future challenges from a combined experimental and modeling perspective.
文摘A new method of long-term culture of cytotrophoblast cells in serum-free medium has been developed. Cytotrophoblast cells were isolated with cold trypsin and purified by unit gravity sedimentation through BSA density gradients. The cells were cultured in the FD medium with supplement of EGF, insulin, transferrin and sodium selenite. They could survive over three weeks. The results showed that both EGF and insulin stimulated hCG and progesterone secretion and that sodium selenite elevated hCG output but not progesterone secretion. Transferrin produced synergistic effect with EGF and insulin on hCG and progesterone secretion but it was ineffective when used alone. This study demonstrates that the four growth factors mentioned above are essential for the survival of cytotrophoblast cells in vitro. It is therefore suggested that EGF, insulin and selenium may possibly be involved in the regulation of hCG and progesterone secretion in the human placenta.
基金Publication of this paper is supported by the National Natural Science Foundation of China （30624808） and Science Publication Foundation of the Chinese Academy of Sciences.Acknowledgements We thank Xianhui Hou （Peking University） for helpful suggestions and valuable discussions.
文摘Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf morphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules, play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis, several fundamental aspects of leaf morphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled. Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.
文摘Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regu- lated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosynthesis, impacts 1-aminocyclopropane 1-carboxylate synthase （ACS） protein stability via the complex interplay of specific factors. Here, we show that the Arabidopsis thaliana protein phosphatase type 2C, ABI1, a negative regulator of abscisic acid signaling, is involved in the regulation of ethylene biosynthesis under oxidative stress conditions. We found that ABI1 interacts with ACS6 and dephosphorylates its C-terminal fragment, a target of the stress-responsive mitogen-activated protein kinase, MPK6. In addition, ABI1 controls MPK6 activity directly and by this means also affects the ACS6 phosphorylation level. Consistently with this, ozone-induced ethylene production was significantly higher in an ABI1 knockout strain （abiltd） than in wild-type plants. Importantly, an increase in stress-induced ethylene production in the abiltd mutant was compen- sated by a higher ascorbate redox state and elevated antioxidant activities. Overall, the results of this study provide evi- dence that ABI1 restricts ethylene synthesis by affecting the activity of ACS6. The ABI1 contribution to stress phenotype underpins its role in the interplay between the abscisic acid （ABA） and ethylene signaling pathways.
文摘Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholipase A （pPLA） genes AtPLAIVA, AtPLAIVB, and AtPLAIVC and their corresponding proteins. Loss-of-function mutants reveal roles for these pPLAs in roots during normal development and under phosphate deprivation. AtPLAIVA is expressed strongly and exclusively in roots and AtplalVA-null mutants have reduced lateral root development, characteristic of an impaired auxin response. By contrast, AtPLAIVB is expressed weakly in roots, cotyledons, and leaves but is transcriptionally induced by auxin, although AtplalVB mutants develop normally. AtPLAIVC is expressed in the floral gynaecium and is induced by abscisic acid （ABA） or phosphate deficiency in roots. While an AtplalVC-1 loss-of-function mutant displays ABA respon- siveness, it exhibits an impaired response to phosphate deficiency during root development. Recombinant AtPLA proteins hydrolyze preferentially galactolipids and, less efficiently, phospholipids, although these enzymes are not localized in chloroplasts. We find that AtPLAIVA and AtPLAIVB are phosphorylated by calcium-dependent protein kinases in vitro and this enhances their activities on phosphatidylcholine but not on phosphatidylglycerol. Taken together, the data reveal novel functions of pPLAs in root development with individual roles at the interface between phosphate deficiency and auxin signaling.
