Plant responses to variable timing of aboveground clipping and belowground herbivory depend on plant age

Aims Plants use different types of responses such as tolerance and induced defense to mitigate the effects of herbivores. The direction and magnitude of both these plant responses can vary with plant age. However, most studies have focused on aboveground herbivory, whereas important feeding occurs belowground. Here, we tested the hypothesis that plant tolerance and defense following shoot damage or root herbivory depends on plant age.     

A Meta-Analysis on the Relationship between Self-Reported Presence and Anxiety in Virtual Reality Exposure Therapy for Anxiety Disorders

In virtual reality exposure therapy (VRET) for anxiety disorders, sense of presence in the virtual environment is considered the principal mechanism that enables anxiety to be felt. Existing studies on the relation between sense of presence and level of anxiety, however, have yielded mixed results on the correlation between the two. In this meta-analysis, we reviewed publications on VRET for anxiety that included self-reported presence and anxiety. The comprehensive search of the literature identified 33 publications with a total of 1196 participants. The correlation between self-reported sense of presence and anxiety was extracted and meta-analyzed. Potential moderators such as technology characteristics, sample characteristics including age, gender and clinical status, disorder characteristics and study design characteristics such as measurements were also examined. The random effects analysis showed a medium effect size for the correlation between sense of presence and anxiety (r = .28; 95% CI: 0.18–0.38). Moderation analyses revealed that the effect size of the correlation differed across different anxiety disorders, with a large effect size for fear of animals (r = .50; 95% CI: 0.30–0.66) and a no to small effect size for social anxiety disorder (r = .001; 95% CI: −0.19–0.19). Further, the correlation between anxiety and presence was stronger in studies with participants who met criteria for an anxiety disorder than in studies with a non-clinical population. Trackers with six degrees of freedom and displays with a larger field of view resulted in higher effect sizes, compared to trackers with three degrees of freedom and displays with a smaller field of view. In addition, no difference in effect size was found for the type of presence measurement and the type of anxiety measurement. This meta-analysis confirms the positive relation between sense of presence and anxiety and demonstrates that this relation can be affected by various moderating factors.     

Incomplete differentiation of antigen-specific CD8 T cells in tumor-draining lymph nodes

CD8 T cells lacking effector activity have been recovered from lymphoid organs of mice and patients with progressing tumors. We explored the basis for lack of effector activity in tumor-bearing mice by evaluating Ag presentation and CD8 T cell function in lymphoid organs over the course of tumor outgrowth. Early after tumor injection, cross-presentation by bone marrow-derived APC was necessary for T cell activation, inducing proliferation and differentiation into IFN-gamma-producing, cytolytic effectors. At later stages of outgrowth, tumor metastasized to draining lymph nodes. Both cross- and direct presentation occurred, but T cell differentiation induced by either modality was incomplete (proliferation without cytokine production). T cells within tumor-infiltrated nodes differentiated appropriately if Ag was presented by activated, exogenous dendritic cells. Thus, activated T cells lacking effector function develop through incomplete differentiation in the lymph nodes of late-stage tumor-bearing mice, rather than through suppression of previously differentiated cells.     

Polar secretion of von Willebrand factor by endothelial cells

Human umbilical vein endothelial cells cultured on a collagen lattice were used to study the polarity of von Willebrand factor (vWF) secretion. Endothelial cells cultured under these conditions allow direct measurements of substances released at both the apical and basolateral surface. The constitutive secretion of vWF was compared to the release of vWF from their storage granules after stimulation (regulated secretion). The basal, constitutive release of vWF occurs into both the apical and subendothelial direction. The rate of accumulation of vWF to the subendothelial direction is about three times higher than the amount of vWF secreted into the lumenal medium per unit of time. However, upon stimulation of confluent endothelial cell monolayers with phorbol myristate acetate, endothelial cells predominantly secrete vWF at the lumenal surface. Under these conditions, vWF does not accumulate in the collagen matrix. Thus, endothelial cells are able to organize themselves into a polarized monolayer, in such a way that vWF secreted by the regulated pathway accumulates at the lumenal site, whereas resting endothelial cells release vWF predominantly at the opposite, basolateral surface.     

Signaling through the lymphotoxin-beta receptor stimulates HIV-1 replication alone and in cooperation with soluble or membrane-bound TNF-alpha

The level of ongoing HIV-1 replication within an individual is critical to HIV-1 pathogenesis. Among host immune factors, the cytokine TNF-alpha has previously been shown to increase HIV-1 replication in various monocyte and T cell model systems. Here, we demonstrate that signaling through the TNF receptor family member, the lymphotoxin-beta (LT-beta) receptor (LT-betaR), also regulates HIV-1 replication. Furthermore, HIV-1 replication is cooperatively stimulated when the distinct LT-betaR and TNF receptor systems are simultaneously engaged by their specific ligands. Moreover, in a physiological coculture cellular assay system, we show that membrane-bound TNF-alpha and LT-alpha1beta2 act virtually identically to their soluble forms in the regulation of HIV-1 replication. Thus, cosignaling via the LT-beta and TNF-alpha receptors is probably involved in the modulation of HIV-1 replication and the subsequent determination of HIV-1 viral burden in monocytes. Intriguingly, surface expression of LT-alpha1beta2 is up-regulated on a T cell line acutely infected with HIV-1, suggesting a positive feedback loop between HIV-1 infection, LT-alpha1beta2 expression, and HIV-1 replication. Given the critical role that LT-alpha1beta2 plays in lymphoid architecture, we speculate that LT-alpha1beta2 may be involved in HIV-associated abnormalities of the lymphoid organs.     

赖氨酰氧化酶与人类疾病

赖氨酰氧化酶(lysyl oxidases,LOXs)是一种能够催化细胞外基质蛋白(如胶原和弹性蛋白)交叉连接的酶类,这一功能使其在组织的稳定、重塑和伤口愈合中发挥重要作用.随着研究的不断深入,LOXs在细胞增殖、细胞趋化以及肿瘤发生等过程中也彰显出十分关键的作用.研究发现,一些诸如结缔组织病、剥脱综合症、铜代谢障碍性疾病及盆腔器官脱垂和骨疾等疾病的发生与LOXs有很大关系.综述了LOXs的生物合成、结构特点、多功能性以及与人类疾病的关系.