The miR156 juvenility factor and PLETHORA 2 form a regulatory network and influence timing of meristem growth and lateral root emergence.

Plants develop throughout their lives: seeds become seedlings that mature and form fruits and seeds. Although the underlying mechanisms that drive these developmental phase transitions have been well elucidated for shoots, the extent to which they affect the root is less clear. However, root anatomy does change as some plants mature; meristems enlarge and radial thickening occurs. Here, in Arabidopsis thaliana, we show that overexpressing miR156A, a gene that promotes the juvenile phase, increased the density of the root system, even in grafted plants in which only the rootstock had the overexpression genotype. In the root, overexpression of miR156A resulted in lower levels of PLETHORA 2, a protein that affects formation of the meristem and elongation zone. Crossing in an extra copy of PLETHORA 2 partially rescued the effects of miR156A overexpression on traits affecting root architecture, including meristem length and the rate of lateral root emergence. Consistent with this, PLETHORA 2 also inhibited the root-tip expression of another miR156 gene, miR156C. We conclude that the system driving phase change in the shoot affects developmental progression in the root, and that PLETHORA 2 participates in this network.

Translation and Validation of the Self-Assessment Psoriasis Area Severity Index.

BACKGROUND: The self-assessment psoriasis area severity index (SAPASI) is a patient-administered psoriasis assessment tool for which we present a validated translation from English to Swedish. METHODS: Validity was evaluated in this single-centre study using the psoriasis area severity index (PASI) as the standard. Test-retest reliability was assessed using repeated SAPASI measurements. RESULTS: Significant correlations (p < 0.0001) using Spearman's correlation coefficient (r) were found between PASI and SAPASI scores (r = 0.60) for 51 participants (median baseline PASI 4.4, interquartile range [IQR]: 1.8-5.6) and repeated SAPASI measurements (r = 0.70) among 38 participants (median baseline SAPASI 4.0, IQR: 2.5-6.1). Bland-Altman plots showed generally higher SAPASI scores than PASI scores. CONCLUSION: The translated version of SAPASI is valid and reliable, although patients generally tend to overrate their disease severity compared to PASI. Keeping this limitation in mind, SAPASI has the potential of being implemented as a time- and cost-efficient assessment tool in a Scandinavian context.

Methotrexate Use for Patients with Psoriasis and Risk of Cutaneous Squamous Cell Carcinoma: A Nested Case-control Study.

An association between methotrexate use and risk of cutaneous squamous cell carcinoma has been reported in patients with rheumatoid and psoriatic arthritis. A nested case-control study was performed to investigate if methotrexate use among patients with psoriasis was associated with increased risk of cutaneous squamous cell carcinoma. Data were obtained from Swedish registers and included 623 patients with psoriasis and a first cutaneous squamous cell carcinoma from 2010 to 2016. Ten randomly selected patients with psoriasis were matched on age and sex to each case. Among cases, 160 (26%) were ever-users of metho-trexate. The corresponding number among the controls was 1,370 (22%), yielding an unadjusted odds ratio (OR) of 1.23 (95% confidence interval (95% CI) 1.02-1.49); p = 0.034. After adjusting for use of other immunosuppressive drugs the association was close to unity (OR 1.09; 95% CI 0.89-1.34); p = 0.39. The slightly increased risk of cutaneous squamous cell carcinoma associated with methotrexate-exposure in patients with psoriasis does not seem to be associated with metho-trexate, but rather with disease severity, other anti-psoriatic treatments, and ultraviolet exposure.

Impact of Bariatric Surgery on Moderate to Severe Psoriasis: A Retrospective Nationwide Registry Study.

Studies of the effects of bariatric surgery on psoriasis are few, with conflicting results. By linking the Swedish National Register for Systemic Treatment of Psoriasis (PsoReg) with the Scandinavian Obesity Surgery Registry (SOReg), individuals with psoriasis who had undergone bariatric surgery in Sweden during 2008 to 2018 were identified, and matched with data for patients with psoriasis in PsoReg. Psoriasis Area Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were compared between the groups. Altogether, 50 operated individuals (median body mass index (BMI) 38.7 kg/m2]) and 91 non-operated individuals (median BMI 33.0 kg/m2) were included. Control of disease at baseline was good in both groups. Linear mixed models showed no significant difference in psoriasis disease burden, measured as changes in mean PASI (ΔPASI) (-1.2, p = 0.43) and DLQI (ΔDLQI) (-2.2, p = 0.34). In summary, this study demonstrated no significant effect of bariatric surgery on psoriasis disease burden in patients with relatively well-controlled moderate to severe psoriasis.

Periodic Lateral Root Priming: What Makes It Tick?

Conditioning small groups of root pericycle cells for future lateral root formation has a major impact on overall plant root architecture. This priming of lateral roots occurs rhythmically, involving temporal oscillations in auxin response in the root tip. During growth, this process generates a spatial pattern of prebranch sites, an early stage in lateral root formation characterized by a stably maintained high auxin response. To date, the molecular mechanism behind this rhythmicity has remained elusive. Some data implicate a cell-autonomous oscillation in gene expression, while others strongly support the importance of tissue-level modulations in auxin fluxes. Here, we summarize the experimental data on periodic lateral root priming. We present a theoretical framework that distinguishes between a priming signal and its subsequent memorization and show how major roles for auxin fluxes and gene expression naturally emerge from this framework. We then discuss three mechanisms that could potentially induce oscillations of auxin response: cell-autonomous oscillations, Turing-type patterning, and tissue-level oscillations in auxin fluxes, along with specific properties of lateral root priming that may be used to discern which type of mechanism is most likely to drive lateral root patterning. We conclude with suggestions for future experiments and modeling studies.

Potassium-Channel-Independent Relaxing Influence of Adipose Tissue on Mouse Carotid Artery.

Since the cardiovascular consequences of obesity reportedly vary in different types of obesity, we investigated the influence of adipose tissue from different locales on the phenylephrine-induced tone of the mouse carotid artery. Vessels were mounted in a Mulvany-Halpern-type wire myograph, and adipose tissue, from the back (brown) or mesenteric or inguinal subcutaneous (white), was placed around the artery. Contractile responses to phenylephrine were not affected by brown adipose tissue but were reduced (p < 0.001) by either type of white adipose tissue, with no difference between the 2 locales. The relaxing effect persisted in the presence of the Kv7 channel inhibitor XE991 (10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone), the KATP channel inhibitor glibenclamide (1 µM), or the KV channel inhibitor 4-amino pyridine (1 mM), as well as after elevation of the extracellular potassium concentration to 30 mM. Contractions of rat carotid artery were equally reduced by mouse and rat subcutaneous adipose tissue. Thus, white, but not brown, adipose tissue reduces the adrenergic contractions of the carotid artery with no differences between the locales of origin, and the effect appears largely independent of potassium channels.

Analyzing lateral root development: how to move forward.

Roots are important to plants for a wide variety of processes, including nutrient and water uptake, anchoring and mechanical support, storage functions, and as the major interface between the plant and various biotic and abiotic factors in the soil environment. Therefore, understanding the development and architecture of roots holds potential for the manipulation of root traits to improve the productivity and sustainability of agricultural systems and to better understand and manage natural ecosystems. While lateral root development is a traceable process along the primary root and different stages can be found along this longitudinal axis of time and development, root system architecture is complex and difficult to quantify. Here, we comment on assays to describe lateral root phenotypes and propose ways to move forward regarding the description of root system architecture, also considering crops and the environment.

Objective Comparison of Commercially Available Breast Implant Devices.

UNLABELLED: Breast implants are frequently used for both cosmetic breast augmentation and breast reconstruction after mastectomy. Three companies currently offer FDA-approved breast implants (Allergan, Mentor, and Sientra), but their product offerings-including permanent breast implants, breast tissue expanders, sizers, and post-operative warranty-can be difficult to compare because of brand names and company-specific jargon. The ability to have a brand-agnostic understanding of all available options is important for both the surgical trainee as well as the surgeon in clinical practice. After a brief review of the history of breast implant devices, this review utilizes a unique conceptual framework based on variables such as fill material, shape, relative dimensions, and surface coating to facilitate a better understanding of the similarities and differences between the different company's offerings. Specifically, we identify which types of devices are offered by all three companies, those that are offered by only one company, those that have very limited product offerings, and those combinations that are not available at all. Finally, clinical implications are drawn from this framework that can be used by both cosmetic and reconstructive surgeons to counsel patients about all available options. Importantly, this project is entirely independent of any company's funding, support, or input. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Lateral root initiation is a probabilistic event whose frequency is set by fluctuating levels of auxin response.

The locations in which lateral roots arise are determined by local peaks of auxin response driven by whole-plant physiology. The architecture of a plant root system adapts it to the conditions in which it grows: large shoot systems demand large root systems, and growth in soils that have low or patchy nutrient distributions is often best managed by non-uniform patterns of root branching. It is not surprising then that the regulation of lateral root spacing is responsive to a wide array of stimuli. Molecular genetic studies have outlined a mechanism by which multiple modules of auxin response in specific cell types drive lateral root initiation. These peaks of auxin responsiveness are functionally controlled by the growth of the plant and the changing environmental conditions it experiences. Thus, the process of lateral root initiation, which depends on strong local auxin response, is globally mediated.

Root system architecture from coupling cell shape to auxin transport.

Lateral organ position along roots and shoots largely determines plant architecture, and depends on auxin distribution patterns. Determination of the underlying patterning mechanisms has hitherto been complicated because they operate during growth and division. Here, we show by experiments and computational modeling that curvature of the Arabidopsis root influences cell sizes, which, together with tissue properties that determine auxin transport, induces higher auxin levels in the pericycle cells on the outside of the curve. The abundance and position of the auxin transporters restricts this response to the zone competent for lateral root formation. The auxin import facilitator, AUX1, is up-regulated by auxin, resulting in additional local auxin import, thus creating a new auxin maximum that triggers organ formation. Longitudinal spacing of lateral roots is modulated by PIN proteins that promote auxin efflux, and pin2,3,7 triple mutants show impaired lateral inhibition. Thus, lateral root patterning combines a trigger, such as cell size difference due to bending, with a self-organizing system that mediates alterations in auxin transport.

Botany: a record-breaking pollen catapult.

The release of stored elastic energy often drives rapid movements in animal systems, and plant components employing this mechanism should be able to move with similar speed. Here we describe how the flower stamens of the bunchberry dogwood (Cornus canadensis) rely on this principle to catapult pollen into the air as the flower opens explosively. Our high-speed video observations show that the flower opens in less than 0.5 ms--to our knowledge, the fastest movement so far recorded in a plant.

Cardiorespiratory fitness in late adolescence and long-term risk of psoriasis and psoriatic arthritis among Swedish men.

BACKGROUND: Psoriasis is a chronic immune-mediated disease and psoriatic arthritis is a common coexisting condition. Cardiorespiratory fitness is the overall capacity to perform exertion exercise. Low levels of cardiorespiratory fitness are associated with negative health outcomes. Individuals with psoriasis have lower cardiorespiratory fitness compared with individuals without psoriasis. There are no previous studies exploring the association between cardiorespiratory fitness and new-onset psoriasis and psoriatic arthritis. METHODS: With the objective to investigate whether low cardiorespiratory fitness in late adolescence increases the risk for onset of psoriasis and psoriatic arthritis, a cohort of Swedish men in compulsory military service between 1968 and 2005 was created using data from the Swedish Military Service Conscription Register. Cardiorespiratory fitness, estimated by maximum capacity cycle ergometer testing at conscription, was divided into three groups: high, medium, and low. Diagnoses were obtained using the Swedish National Patient Register and cohort members were followed from conscription until an event, new-onset psoriasis or psoriatic arthritis, occurred, or at the latest until 31 December 2016. Cox regression models adjusted for confounders at conscription were used to obtain hazard ratios with 95% confidence intervals for incident psoriasis and psoriatic arthritis. RESULTS: During the follow-up period (median follow-up time 31 years, range 0-48 years), 20,679 cases of incident psoriasis and 6,133 cases of incident psoriatic arthritis were found among 1,228,562 men (mean age at baseline 18.3 years). There was a significant association between low cardiorespiratory fitness and incident psoriasis and psoriatic arthritis (hazard ratio 1.35 (95% confidence interval 1.26-1.44) and 1.44 (95% confidence interval 1.28-1.63), respectively). CONCLUSIONS: These novel findings suggest that low cardiorespiratory fitness at an early age is associated with increased risk of incident psoriasis and psoriatic arthritis among men, and highlight the importance of assessing cardiorespiratory fitness early in life.

Teaching resources. Model of the TIR1 pathway for auxin-mediated gene expression.

Auxin mediates numerous plant responses, some of which have been shown to require transcriptional regulation. One auxin response pathway, which depends on the relief of transcriptional repression, is mediated by TIR1 (transport inhibitor response protein 1). TIR1 is an auxin receptor and also a subunit of an SCF-type ubiquitin ligase. In the presence of a low concentration of auxin in the nucleus, members of the Aux/IAA family of transcriptional repressors bind to ARF proteins and inhibit the transcription of specific auxin response genes. Increased nuclear concentrations of auxin promote auxin binding to TIR1, causing the Aux/IAA proteins to associate with TIR1 and leading to their degradation by a proteasome-mediated pathway. This decreases the concentration of Aux/IAA proteins in the nucleus and thereby enables the expression of certain auxin response genes.

Phyllotaxis and rhizotaxis in Arabidopsis are modified by three PLETHORA transcription factors.

BACKGROUND: The juxtaposition of newly formed primordia in the root and shoot differs greatly, but their formation in both contexts depends on local accumulation of the signaling molecule auxin. Whether the spacing of lateral roots along the main root and the arrangement of leaf primordia at the plant apex are controlled by related underlying mechanisms has remained unclear. RESULTS: Here, we show that, in Arabidopsis thaliana, three transcriptional regulators implicated in phyllotaxis, PLETHORA3 (PLT3), PLT5, and PLT7, are expressed in incipient lateral root primordia where they are required for primordium development and lateral root emergence. Furthermore, all three PLT proteins prevent the formation of primordia close to one another, because, in their absence, successive lateral root primordia are frequently grouped in close longitudinal or radial clusters. The triple plt mutant phenotype is rescued by PLT-vYFP fusion proteins, which are expressed in the shoot meristem as well as the root, but not by expression of PLT7 in the shoot alone. Expression of all three PLT genes requires auxin response factors ARF7 and ARF19, and the reintroduction of PLT activity suffices to rescue lateral root formation in arf7,arf19. CONCLUSIONS: Intriguingly PLT 3, PLT5, and PLT7 not only control the positioning of organs at the shoot meristem but also in the root; a striking observation that raises many evolutionary questions.

Expression profiling of auxin-treated Arabidopsis roots: toward a molecular analysis of lateral root emergence.

Treating Arabidopsis roots with exogenous auxin results in dramatic changes in cellular processes including de novo induction of lateral roots which later emerge through the overlying cells. Microarray experiments reveal approximately 80 genes that are substantially up-regulated in the root over the first 12 h following auxin treatment. We hypothesize that the observed increase in expression of pectate lyase family genes leads to degradation of the pectin-rich middle lamellae, allowing cells in the parent root to separate cleanly. Differences in the degree of pectin methylation in lateral and parent roots may explain why lateral roots are not degraded themselves.

FQR1, a novel primary auxin-response gene, encodes a flavin mononucleotide-binding quinone reductase.

FQR1 is a novel primary auxin-response gene that codes for a flavin mononucleotide-binding flavodoxin-like quinone reductase. Accumulation of FQR1 mRNA begins within 10 min of indole-3-acetic acid application and reaches a maximum of approximately 10-fold induction 30 min after treatment. This increase in FQR1 mRNA abundance is not diminished by the protein synthesis inhibitor cycloheximide, demonstrating that FQR1 is a primary auxin-response gene. Sequence analysis reveals that FQR1 belongs to a family of flavin mononucleotide-binding quinone reductases. Partially purified His-tagged FQR1 isolated from Escherichia coli catalyzes the transfer of electrons from NADH and NADPH to several substrates and exhibits in vitro quinone reductase activity. Overexpression of FQR1 in plants leads to increased levels of FQR1 protein and quinone reductase activity, indicating that FQR1 functions as a quinone reductase in vivo. In mammalian systems, glutathione S-transferases and quinone reductases are classified as phase II detoxification enzymes. We hypothesize that the auxin-inducible glutathione S-transferases and quinone reductases found in plants also act as detoxification enzymes, possibly to protect against auxin-induced oxidative stress.