Initial Suppression Research Articles

Fatty acid binding protein 4 deficiency protects against oxygen-induced retinopathy in mice.

Retinopathy of prematurity (ROP) is a leading cause of blindness in children worldwide due to increasing survival rates of premature infants. Initial suppression, followed by increased production of the retinal vascular endothelial growth factor-A (VEGF) expression are key events that trigger the pathological neovascularization in ROP. Fatty acid binding protein 4 (FABP4) is an intracellular lipid chaperone that is induced by VEGF in a subset of endothelial cells. FABP4 exhibits a pro-angiogenic function in cultured endothelial cells and in airway microvasculature, but whether it plays a role in modulation of retinal angiogenesis is not known. We hypothesized that FABP4 deficiency could ameliorate pathological retinal vascularization and investigated this hypothesis using a well-characterized mouse model of oxygen-induced retinopathy (OIR). We found that FABP4 was not expressed in retinal vessels, but was present in resident macrophages/microglial cells and endothelial cells of the hyaloid vasculature in the immature retina. While FABP4 expression was not required for normal development of retinal vessels, FABP4 expression was upregulated and localized to neovascular tufts in OIR. FABP4−/− mice demonstrated a significant decrease in neovessel formation as well as a significant improvement in physiological revascularization of the avascular retinal tissues. These alterations in retinal vasculature were accompanied by reduced endothelial cell proliferation, but no effect on apoptosis or macrophage/microglia recruitment. FABP4−/− OIR samples demonstrated decreased expression of genes involved in angiogenesis, such as Placental Growth Factor, and angiopoietin 2. Collectively, our findings suggest FABP4 as a potential target of pathologic retinal angiogenesis in proliferative retinopathies.

Ubiquitous Sensor Networks and Image Processing Based Environmental Monitoring System for Fire Safety

In recent years, since the tall buildings are getting increased and getting dense in the city area, those buildings can be more and more exposed to risks such as fire and natural disasters. In case if the high-rise building is on fire, it is not easy to put out the fire even with the modernization of the firefighting equipment. These risks can directly lead to human casualties so that it is necessary to quickly have an initial evacuation or initial suppression risks. In this paper, we propose the integrated method for reducing the fire risks through sensors such as temperature and humidity, ZigBee technology, camera control and image processing technologies, and real-time data transmission technology. Based on our proposed method, it is expected that our integrated system directly leads to the expansion of risk safety management system as well as the development of USN technologies.

Expedited suppression signal in ocular go/no-go decision

When scrutinizing the visual world, complex and unexpected stimuli often lead to prolonged eye fixations to enhance cognitive processing, likely by temporarily suppressing a planned saccade. The present study examined whether the suppression signal is tightly linked to a specific planned saccade and if it conforms to the viewer's intention. A novel Go/No-go task was devised where participants made consecutive saccades to fixate a stimulus appearing across the screen horizontal meridian in 4° steps. At times, the features of the stimulus (colour and/or shape) were altered when it reappeared at a new location. Participants had to suppress the saccade that would otherwise leave the stimulus if its features matched instructed criteria. Saccade suppression was determined by the reduced probability for saccades towards and away from a target stimulus. Results show both correct suppression to saccades leaving the target and erroneous suppression to saccades towards it. The erroneous suppression was initially observed for any change in features but later lifted. The suppression shortened the length of saccades leaving a target but not those towards it. The initial suppression during previewing the target appears to be based on expedited but incomplete evaluation of visual stimulus, and is not linked to any specific saccade. These properties might reflect the stage of ocular decision based on which the suppression signal is generated. They also account for the phenomenon of “peripheral-to-foveal” effect on eye movements in reading.

Fire weather and large fire potential in the northern Sierra Nevada

Fuels, weather, and topography all contribute to observed fire behavior. Of these, weather is not only the most dynamic factor, it is the most likely to be directly influenced by climate change. In this study 40 years of daily fire weather observations from five weather stations across the northern Sierra Nevada were analyzed to investigate potential changes or trends in the frequency of high- to extreme-fire weather. The analysis demonstrated fairly strong upward trends in the occurrence of high- to extreme-fire weather, particularly since the mid-1990s. This increased occurrence of high fire weather conditions suggests that there is more opportunity for fires to grow rapidly and overwhelm initial suppression efforts, likely resulting in greater incidence of large fires throughout the region. This is particularly problematic in the northern Sierra Nevada, where there is a complex arrangement of land ownerships, including numerous human communities.

Glucose-induced inhibition of insulin secretion

Increase in glucose is known to elevate the concentration of cytoplasmic Ca(2+) ([Ca(2+) ]i ) in pancreatic β-cells and stimulate insulin secretion. However, rise of glucose can also lower [Ca(2+) ]i and inhibit insulin release. In the present review, we examine the mechanisms for this inhibition and highlight its importance for the healthy β-cell and the development of diabetes. It is possible to distinguish between 60 and 90 s of prompt inhibition and the late inhibition seen after the first-phase peak of insulin release. The introductory inhibition is characteristic of the healthy β-cell and mediated by sequestration of [Ca(2+) ]i in the endoplasmic reticulum. This inhibition is easily seen in studies of isolated islets but too brief to be detected in a conventional intravenous glucose tolerance test. Coupled to simultaneous rise of glucagon, the introductory suppression of insulin release is the starting point for the antiphase relation between the subsequent insulin and glucagon pulses. Another effect of the initial suppression is to increase the pool of readily releasable granules responsible for the first-phase release of insulin. The presence of late inhibition of insulin release is an indicator of β-cell dysfunction. Patients with type 2 diabetes often respond to intravenous bolus injection of glucose with 5-10 min of late suppression of circulating insulin.

棉花长期连作对新疆土壤细菌群落结构的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 棉花长期连作对新疆土壤细菌群落结构的影响 DOI: 10.5846/stxb201212181817 作者: 作者单位: 新疆师范大学生命科学学院,新疆农业科学院微生物应用研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（30860016）；新疆师范大学科研处（XJNUBS1004）；微生物重点学科资助项目 Analysis of the bacterial communities in continuous cotton fields of Xinjiang Province Author: Affiliation: College of life science,XinJiang normal university,Institute of Microbiology,Xinjiang Academy of Agricultural Sciences Urumqi Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:新疆部分棉区发生连作障碍后与其他地区有所不同，能自发恢复并长期保持高产、稳产，为了查明该类棉田土壤细菌群落结构在连作障碍发生及自发恢复整个过程中的演替规律。以未开垦土地作为对照，利用16S rRNA-PCR-DGGE（polymerase chain reaction-density gradient gel electrophoresis）法对比研究了新疆阿克苏棉区分别连作1、3、5、10、15和20a棉田1-30 cm深度土壤细菌群落结构组成。结果表明未开垦土地细菌多样性指数丰富度最高，多样性和均匀度指数最低。随着棉花连作年限的延长，土壤细菌群落丰富度指数不断下降，而多样性和均匀度指数逐渐增大。当连作年限继续延长至10a后各指数出现恢复或趋于达到一个新的相对稳定状态。聚类分析显示7个样品分别聚为3簇，其中连作3a的样品差异最大，相似度仅有44%，而连作10a后的样品和对照较为相似。主成分分析也有类似的结果。对比回收的部分序列显示，序列间相似性在88%以上，分属于Microbacterium、Uncultured Chloroflexi bacterium、TM7 Phylum sp. Canine、Flavobacteria等4个不同菌属。分析认为棉花长期连作对该地区土壤细菌群落结构组成影响很大，但随着连作年限延长至5a以后，细菌群落结构组成能自发趋于稳定和回升。此外，对比棉田细菌群落结构整体变化规律和棉花产量的增减及病虫害发生规律发现，在棉花长期连作过程中两者有很强的关联性。 Abstract:Long-term continuous cropping of cotton has caused dramatic soil-borne diseases in many places, leading to substantial agricultural losses. However, in some areas of Xingjang Province, the obstacles caused by continuous cotton cropping can spontaneously restore and maintain high yields of cotton for many years. To analyze the variable spectrum of soil bacterial communities and changes in the community structure in these spontaneously restored fields during cropping, soils at depths from 1 to 30 cm were sampled from cotton fields with a history of 0, 1, 3, 5, 10, 15 or 20 years of cotton cropping in the Akesu region of Xinjiang Province. The bacterial communities in these samples were studied using 16S rRNA-based polymerase chain reaction-density gradient gel electrophoresis (PCR-DGGE) with samples from uncultivated land as a control. Bacterial community diversity indices including the Shannon-Wiener diversity (H), Abundance index (S) and Evenness index (EH) were compared among these samples. Samples from uncultivated land had relatively high levels of the richness indices but both the Diversity and Evenness Indices were at lower levels. With increasing years of cotton cropping, both the bacterial Diversity and Evenness Indices increased, whereas the richness indices showed a general decrease. However, after 10 years of continuous cropping all these indices were restored to their original values or reached a relative stable level. Cluster analysis of DGGE fragments indicated that the seven samples were clustered into three branches: fragments from samples under successional cropping for 0, 10 and 20 years formed one small branch with a similarity of approximately 50%; fragments from successional cropping for 1, 5 and 15 years formed another branch with a similarity of 53%; and the last branch comprised fragments from successional cropping for 3 years with a similarity of 44%. Principal component analysis (PCA) showed that all of the samples were statistically correlated with the major component and fluctuated on the right of the major component between the positive and negative axes of the second principal component. Both cluster analysis and PCA results suggested that, compared to those from original uncropped fields, the bacterial community structure showed the most variation in samples from the field of 3-year cropping, whereas similar patterns of bacterial community structure were found between samples from fields of 10 years of cotton cropping and those from uncropped fields. Nineteen clones were sequenced from each band and among them one sequence was selected and submitted to GenBank (accessory no. JN572545-JN572563). By aligning with the GenBank database, all sequences from DGGE were classified into four groups: Microbacterium, Uncultured Chloroflexi bacterium, TM7 Phylum sp. canine, and Flavobacteria. Further analysis demonstrated that the isolated V3 sequences showed a homology of 88%-100% to known sequences in GenBank and 47% of the sequences belonged to bacteria which were not cultured. No microbial data were correlated with soil-borne plant diseases of cotton. The study demonstrated that the age of cotton fields had significant effects on soil bacterial diversity. Continuous cotton cropping exerted significant influences on the community structure of soil bacteria in Xinjiang Province, with an initial suppression effect on bacterial diversity. However, the bacterial community reached a stabilized or even increased level compared with its original state after 5 years of continuous cropping. In addition, correlations between variations in the bacterial community structure at a depth of 1-30 cm and the yield of cotton and pest disease attacks were also found in this study. 参考文献 相似文献 引证文献

Effect of monochromatic excimer light on palmoplantar pustulosis: A clinical study performed in a private clinic by a dermatological specialist

Palmoplantar pustulosis (PPP) is currently treated with various modalities, including excimer light, a form of ultraviolet lamp. This study reports effect of excimer light treatment in 34 Japanese PPP patients treated at a private clinic by one doctor, who was certified as a dermatological specialist by the Japanese Dermatological Association. The statistical analyses were performed upon a collaborative basis with faculties in universities. Disease response scores were determined by response to excimer light treatment. Scores of 1, 2, 3 or 4 were assigned to patients whose palmoplantar pustular psoriasis area and severity index (PPPASI) decreased to 25% or less, 25.1-50%, 50.1-75% or more than 75.1% of pretreatment PPPASI, respectively. In this study, 44.1% PPP cases had scores of 1 or 2, and considered good responders to excimer light treatment. There were no statistical differences between males and females, and between older (≥40years) and younger groups (≤39years) in terms of disease response score. Disease duration did not show any significant difference among these scores. Treatment times, total amount of ultraviolet and total treatment duration showed significant differences between score 1 and score 4 groups (P=0.0164, =0.0137 and =0.0267, respectively). Particular interest was paid to smoking habits. Smoking in male patients was significantly higher than that in female patients (P=0.0169). There was no statistical difference between smokers and non-smokers in terms of response to excimer light. In conclusion, this study suggested that excimer light is useful for both initial regimen and suppression of exacerbation in treatments of PPP.

Temporal Association Between Incident Tuberculosis and Poor Virological Outcomes in a South African Antiretroviral Treatment Service

Introduction:The temporal relationship between incident tuberculosis (TB) and virological outcomes during antiretroviral therapy (ART) is poorly defined. This was studied in a cohort in Cape Town, South Africa.Methods:Data regarding TB diagnoses, ART regimens, and 4-monthly updated viral load (VL) and CD4 count measurements were extracted from a prospectively maintained database. Rates of virological breakthrough (VL > 1000 copies/mL) and failure (VL > 1000 copies/mL on serial measurements) following initial VL suppression were calculated. Poisson models were used to calculate incidence rate ratios (IRRs) and identify risk factors for these virological outcomes.Results:Incident TB was diagnosed in 391 (28.5%) of 1370 patients during a median of 5.2 years follow-up. Five hundred seventy-eight episodes of virological breakthrough and 231 episodes of virological failure occurred, giving rates of 10.0 episodes per 100 person-years and 4.0 episodes per 100 person-years, respectively. In multivariate analyses adjusted for baseline and time-updated risk factors, TB was an independent risk factor for adverse virological outcomes. These associations were strongly time dependent; the 6-month period following diagnosis of incident TB was associated with a substantially increased risk of virological breakthrough (IRR: 2.3, 95% confidence interval: 1.7 to 3.2) and failure (IRR: 2.6, 95% confidence interval: 1.6 to 4.3) compared with time without a TB diagnosis. Person-time preceding TB diagnosis or more than 6 months after a TB diagnosis was not associated with poor virological outcomes.Conclusions:Incident TB during ART was strongly associated with poor virological outcomes during the 6-month period following TB diagnosis. Although underlying mechanisms remain to be defined, patients with incident TB may benefit from virological monitoring and treatment adherence support.

Macrophage polarization in response to wear particles in vitro.

Total joint replacement is a highly successful surgical procedure for treatment of patients with disabling arthritis and joint dysfunction. However, over time, with high levels of activity and usage of the joint, implant wear particles are generated from the articulating surfaces. These wear particles can lead to activation of an inflammatory reaction, and subsequent bone resorption around the implant (periprosthetic osteolysis). Cells of the monocyte/macrophage lineage orchestrate this chronic inflammatory response, which is dominated by a pro-inflammatory (M1) macrophage phenotype rather than an anti-inflammatory pro-tissue healing (M2) macrophage phenotype. While it has been shown that interleukin-4 (IL-4) selectively polarizes macrophages towards an M2 anti-inflammatory phenotype which promotes bone healing, rather than inflammation, little is known about the time course in which this occurs or conditions in which repolarization through IL-4 is most effective. The goal of this work was to study the time course of murine macrophage polarization and cytokine release in response to challenge with combinations of polymethyl methacrylate (PMMA) particles, lipopolysaccharide (LPS) and IL-4 in vitro. Treatment of particle-challenged monocyte/macrophages with IL-4 led to an initial suppression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) production and subsequent polarization into an M2 anti-inflammatory phenotype. This result was optimized when IL-4 was delivered before PMMA particle challenge, to an M1 phenotype rather than to uncommitted (M0) macrophages. The effects of this polarization were sustained over a 5-day time course. Polarization of M1 macrophages into an M2 phenotype may be a strategy to mitigate wear particle associated periprosthetic osteolysis.

Variations in dissipation rate, microbial function and antibiotic resistance due to repeated introductions of manure containing sulfadiazine and chlortetracycline to soil

Antibiotic persistence following five successive treatments of sulfadiazine (SDZ) and chlortetracycline (CTC), alone and in combination, in manure-amended soil was studied under laboratory conditions. The resulting effects on soil respiration and enzyme activities as well as pollution-induced community tolerance, were also examined. A trend of initial suppression followed by recovery was observed in the dissipation rates of SDZ or CTC during the antibiotic treatments, and combined treatment with both antibiotics did not alter the respective dissipation rates significantly. Soil respiration activity with SDZ and/or CTC treatments was inhibited during the initial two treatments; however, the activity thereafter recovered to or exceeded the level of the individual manure treatment. Initially, soil urease and dehydrogenase activities were not affected; however, after the fifth treatment, these activities were significantly stimulated in the CTC individual and combined treatments compared with their activities in the individual manure treatment. Bacterial community tolerance to SDZ and CTC in manure-amended soil increased significantly (p⩽0.05) with antibiotic treatment frequency.

Poor Early Virologic Performance and Durability of Abacavir-based First-line Regimens for HIV-infected Children

Concerns about stavudine (d4T) toxicity have led to increased use of abacavir (ABC) in first-line pediatric antiretroviral treatment (ART) regimens. Field experience with ABC in ART-naïve children is limited. Deidentified demographic, clinical and laboratory data on HIV-infected children initiating ART between 2004 and 2011 in a large pediatric HIV treatment program in Johannesburg, South Africa, were used to compare viral suppression at 6 and 12 months by initial treatment regimen, time to suppression (<400 copies/mL) and rebound (>1000 copies/mL after initial suppression). Adjusted logistic regression was used to investigate confounders and calendar effects. Two thousand thirty-six children initiated either d4T/3TC- or ABC/3TC-based first-line regimens in combination with either boosted lopinavir (LPV/r) or efavirenz (EFV). 1634 received d4T regimens (LPV/r n = 672; EFV n = 962) and 402 ABC regimens (LPV/r n = 192; EFV n = 210). At 6 and 12 months on ART, viral suppression rate was poorer in ABC versus d4T groups within both the LPV/r and EFV groups (P < 0.0001 for all points). In ABC groups, time to suppression was significantly slower (log-rank P < 0.0001 and P = 0.0092 for LPV/r- and EFV-based, respectively) and time to rebound after suppression significantly faster (log-rank P = 0.014 and P = 0.0001 for LPV/r- and EFV-based, respectively). Logistic regression confirmed the worse outcomes in the ABC groups even after adjustment for confounders. Data from this urban pediatric ART service program show significantly poorer virological performance of ABC compared with d4T-based regimens, a signal that urgently warrants further investigation.

Randomised pilot study of dose escalation using conformal radiotherapy in prostate cancer: long-term follow-up

Background:Radical three-dimensional conformal radiotherapy (CFRT) with initial androgen suppression (AS) is a standard management for localised prostate cancer (PC). This pilot study evaluated the role of dose escalation and appropriate target volume margin. Here, we report long-term follow-up.Methods:Eligible patients had T1b-T3b N0 M0 PC. After neoadjuvant AS, they were randomised to CFRT, giving (a) 64 Gy with either a 1.0- or 1.5-cm margin and (b) ±10 Gy boost to the prostate alone.Results:One hundred and twenty-six men were randomised and treated. Median follow-up was 13.7 years. The median age was 66.6 years at randomisation. Median presenting prostate-specific antigen (PSA) was 14 ng ml−1. Sixty-four out of 126 patients developed PSA failure. Forty-nine out of 126 patients restarted AS, 34 out of 126 developed metastases and 28 out of 126 developed castrate-resistant prostate cancer (CRPC). Fifty-one out of 126 patients died; 19 out of 51 died of PC. Median overall survival (OS) was 14.4 years. Although escalated dose results were favourable, no statistically significant differences were seen between the randomised groups; PSA control (hazard ratio (HR): 0.77 (95% confidence interval (CI): 0.47–1.26)), development of CRPC (HR: 0.81 (95% CI: 0.40–1.65)), PC-specific survival (HR: 0.59 (95% CI:0.23–1.49)) and OS (HR: 0.81 (95% CI: 0.47–1.40)). There was no evidence of a difference in PSA control according to margin size (HR: 1.01 (95% CI: 0.61–1.66)).Interpretation:Long-term follow-up of this small pilot study is compatible with a benefit from dose escalation, but confirmation from larger trials is required. There was no obvious detriment using the smaller radiotherapy margin.

Role of Rck-Pat1b binding in assembly of processing-bodies

The DEAD box RNA helicase Rck and the scaffold protein Pat1b participate in controlling gene expression at the post-transcriptional level by suppressing mRNA translation and promoting mRNA decapping. In addition, both proteins are required for the assembly of processing (P)-bodies, cytoplasmic foci that contain stalled mRNAs and numerous components of the mRNA decay machinery. The C-terminal RecA-like domain of Rck interacts with the N-terminal acidic domain of Pat1b. Here, we identified point mutations in human Rck and Pat1b that prevent the two proteins from binding to each other. By analyzing interaction-deficient mutants in combination with knockdown and rescue strategies in human HeLa cells, we found that Pat1b assembles P-bodies and suppresses expression of tethered mRNAs in the absence of Rck binding. In contrast, Rck requires the Pat1b-binding site in order to promote P-body assembly and associate with the decapping enzyme Dcp2 as well as Ago2 and TNRC6A, two core components of the RNA-induced silencing complex. Our data indicate that P-body assembly occurs in a step-wise manner, where Rck participates in the initial suppression of mRNA translation, whereas Pat1b in a second step triggers P-body assembly and promotes mRNA decapping.

Stimulation of PAR2 during OIR reduces endothelial cell death and provokes rapid revascularization

In the retina, a highly regulated vascular meshwork irrigates neurons and supplies necessary metabolic requirements. Sustained vessel loss, as in Retinopathy of Prematurity (ROP), prompts revascularization despite initial suppression of vaso‐survival cues such as VEGF. Thus, other forces are likely involved. Importantly, we have previously demonstrated the substantial role of Protease‐activated receptor 2 (PAR2), a GPCR, in the developing retina. The exact mechanism by which PAR‐2 modulates angiogenic cues in ROP remains elusive.Expression and localization of PAR2 was determined by Western blot and immunohistochemistry in mouse whole retina. Appraisal of retinal vasculature and expression of pro‐ and anti‐angiogenic cues was assessed following intravitreal administration of PAR2 agonist peptide (SLIGRL) or lentiviral shRNA knockdown of PAR2 (LV shPAR2) in mice exposed to a murine oxygen‐induced retinopathy model (75% O2 from P7‐P12).Our results demonstrate a pronounced expression of PAR2 preferentially in RGC. PAR2 sharply increases during the initial phases of vaso‐obliteration (VO) and during the neovascularization (NV) phase. Activation of PAR2 with SLIGRL in vivo reduced Sema3A while increasing VEGF. Importantly, SLIGRL treatment in vivo prior to and following oxygen exposure significantly decreased VO and NV. Treatment with LV shPAR2 increased VO while augmenting NV.This study underscores the importance of the coupling between neurons and vessels and shows that RGC‐specific PAR2 plays a pivotal role in modulating angiogenesis in a pathological context.

Need for Effective Technology Transfer to Ensure Sustainability of Otta Seal

The Otta (graded aggregate) seal technology originated in the 1960s in the Otta Valley in Norway. This type of bituminous seal was first introduced to Botswana in the late 1970s with design and construction being initially undertaken in-house and subsequently by the private sector. However, a somewhat haphazard approach to the transfer of this relatively new technology from the public to the private sector was largely responsible for initial suppression of the acceptance of this innovative type of surfacing despite its eminent suitability for use with locally available, marginal-quality aggregates. Many lessons were learned from this experience; these lessons are likely to be useful to other countries in which the introduction of the Otta seal is being contemplated. The primary objective of this study is to highlight the critical importance of undertaking effective technology transfer to ensure the sustainability of any new type of technology, such as the Otta seal. The path from research to implementation of new technology is considered, including the typical constraints and barriers faced in the African region. In the context of the Otta seal experience in Botswana, typical barriers and constraints to its ready adoption by the private sector are identified and measures for overcoming them are proposed. It is concluded that a carefully crafted, proactive approach to technology transfer is necessary to ensure the sustainability of the Otta seal in countries where it is being introduced for the first time.

Dynamics of Strigolactone Function and Shoot Branching Responses in Pisum sativum

Strigolactones (SLs), or their metabolites, were recently identified as endogenous inhibitors of shoot branching. 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 addition 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.

Osteoblast Lineage-Specific Effects of Notch Activation in the Skeleton

Transgenic overexpression of the Notch1 intracellular domain inhibits osteoblast differentiation and causes osteopenia, and inactivation of Notch1 and Notch2 increases bone volume transiently and induces osteoblastic differentiation. However, the biology of Notch is cell-context-dependent, and consequences of Notch activation in cells of the osteoblastic lineage at various stages of differentiation and in osteocytes have not been defined. For this purpose, Rosa(Notch) mice, where a loxP-flanked STOP cassette placed between the Rosa26 promoter and the NICD coding sequence, were crossed with transgenics expressing the Cre recombinase under the control of the Osterix (Osx), Osteocalcin (Oc), Collagen 1a1 (Col2.3), or Dentin matrix protein1 (Dmp1) promoters. At 1 month, Osx-Cre;Rosa(Notch) and Oc-Cre;Rosa(Notch) mice exhibited osteopenia due to impaired bone formation. In contrast, Col2.3-Cre;Rosa(Notch) and Dmp1-Cre;Rosa(Notch) exhibited increased femoral trabecular bone volume due to a decrease in osteoclast number and eroded surface. In the four lines studied, cortical bone was either not present, was porous, or had the appearance of trabecular bone. Oc-Cre;Rosa(Notch) and Col2.3-Cre;Rosa(Notch) mice exhibited early lethality so that their adult phenotype was not established. At 3 months, Osx-Cre;Rosa(Notch) and Dmp1-Cre;Rosa(Notch) mice displayed increased bone volume, and increased osteoblasts although calcein-demeclocycline labels were diffuse and fragmented, indicating abnormal bone formation. In conclusion, Notch effects in the skeleton are cell-context-dependent. When expressed in immature osteoblasts, Notch arrests their differentiation, causing osteopenia, and when expressed in osteocytes, it causes an initial suppression of bone resorption and increased bone volume, a phenotype that evolves as the mice mature.

Children's dynamic RSA change during anger and its relations with parenting, temperament, and control of aggression

This study examined the moderating effects of child temperament on the association between maternal socialization and 4–6-year-old children's dynamic respiratory sinus arrhythmia (RSA) change in response to anger-themed emotional materials (N=180). We used latent growth curve modeling to explore adaptive patterns of dynamic RSA change in response to anger. Greater change in RSA during anger-induction, characterized by more initial RSA suppression and a subsequent return to baseline, was related to children's better regulation of aggression. For anger-themed materials, low levels of authoritarian parenting predicted more RSA suppression and recovery for more anger-prone children, whereas more authoritative parenting predicted more RSA suppression and recovery for less anger-prone children. These findings suggest that children's adaptive patterns of dynamic RSA change can be characterized by latent growth curve modeling, and that these patterns may be differentially shaped by parent socialization experiences as a function of child temperament.

Molecular Cytogenetics (FISH, GISH) of Coccinia grandis: A ca. 3 myr-Old Species of Cucurbitaceae with the Largest Y/Autosome Divergence in Flowering Plants

The independent evolution of heteromorphic sex chromosomes in 19 species from 4 families of flowering plants permits studying X/Y divergence after the initial recombination suppression. Here, we document autosome/Y divergence in the tropical Cucurbitaceae Coccinia grandis, which is ca. 3 myr old. Karyotyping and C-value measurements show that the C. grandis Y chromosome has twice the size of any of the other chromosomes, with a male/female C-value difference of 0.094 pg or 10% of the total genome. FISH staining revealed 5S and 45S rDNA sites on autosomes but not on the Y chromosome, making it unlikely that rDNA contributed to the elongation of the Y chromosome; recent end-to-end fusion also seems unlikely given the lack of interstitial telomeric signals. GISH with different concentrations of female blocking DNA detected a possible pseudo-autosomal region on the Y chromosome, and C-banding suggests that the entire Y chromosome in C. grandis is heterochromatic. During meiosis, there is an end-to-end connection between the X and the Y chromosome, but the X does not otherwise differ from the remaining chromosomes. These findings and a review of plants with heteromorphic sex chromosomes reveal no relationship between species age and degree of sex chromosome dimorphism. Its relatively small genome size (0.943 pg/2C in males), large Y chromosome, and phylogenetic proximity to the fully sequenced Cucumis sativus make C. grandis a promising model to study sex chromosome evolution.

BiotecVisions 2012, October

BiotecVisions 2012, October