The cuticle is the outer physical barrier of aerial plant surfaces and an important interaction point between plants and the environment. Many environmental stresses affect cuticle formation, yet the ...regulatory pathways involved remain undefined. We used a genetics and gene expression analysis in Arabidopsis thaliana to define an abscisic acid （ABA） signaling loop that positively regulates cuticle formation via the core ABA signaling pathway, including the PYR/PYL receptors, PP2C phosphatase, and SNF1-Related Protein Kinase （SnRK） 2.21SnRK2.3/SnRK2.6. Downstream of the SnRK2 kinases, cuticle formation was not regulated by the ABA-responsive element-binding transcription factors but rather by DEWAX, MYB16, MYB94, and MYB96. Additionally, low air humidity increased cuticle formation independent of the core ABA pathway and cell death/reactive oxygen species signaling attenuated expression of cuticle-biosynthesis genes. In Physcornitrella patens, exogenous ABA suppressed expression of cuticle- related genes, whose Arabidopsis orthologs were ABA-induced. Hence, the mechanisms regulating cuticle formation are conserved but sophisticated in land plants. Signaling specifically related to cuticle deficiency was identified to play a major role in the adaptation of ABA signaling pathway mutants to increased humidity and in modulating their immunity to Botrytis cinerea in Arabidopsis. These results define a cuticle-specific downstream branch in the ABA signaling pathway that regulates responses to the external environment.
In seed plants, strigolactones (SLs) regulate architecture and induce mycorrhizal symbiosis in response to environmental cues. SLs are formed by combined activity of the carotenoid cleavage ...dioxygenases (CCDs) 7 and 8 from 9-cis-β-carotene, leading to carlactone that is converted by cytochromes P450 (clade 711; MAX1 in Arabidopsis) into various SLs. As Physcomitrella patens possesses CCD7 and CCD8 homologs but lacks MAX1, we investigated if PpCCD7 together with PpCCD8 form carlactone and how deletion of these enzymes influences growth and interactions with the environment.
We investigated the enzymatic activity of PpCCD7 and PpCCD8 in vitro, identified the formed products by high performance liquid chromatography (HPLC) and LC-MS, and generated and analysed ΔCCD7 and ΔCCD8 mutants.
We defined enzymatic activity of PpCCD7 as a stereospecific 9-cis-CCD and PpCCD8 as a carlactone synthase. ΔCCD7 and ΔCCD8 lines showed enhanced caulonema growth, which was revertible by adding the SL analogue GR24 or carlactone. Wild-type (WT) exudates induced seed germination in Orobanche ramosa. This activity was increased upon phosphate starvation and abolished in exudates of both mutants. Furthermore, both mutants showed increased susceptibility to phytopathogenic fungi.
Our study reveals the deep evolutionary conservation of SL biosynthesis, SL function, and its regulation by biotic and abiotic cues.
To cite this article: Videler WJ, Badia L, Harvey RJ, Gane S, Georgalas C, van der Meulen FW, Menger DJ, Lehtonen MT, Toppila‐Salmi SK, Vento SI, Hytönen M, Hellings PW, Kalogjera L, Lund VJ, ...Scadding G, Mullol J, Fokkens WJ. Lack of Efficacy of long‐term, low‐dose azithromycin in chronic rhinosinusitis: a randomized controlled trial. Allergy 2011; 66: 1457–1468.
Background: In persistent chronic rhinosinusitis (CRS), conventional treatment is often insufficient. Long‐term, low‐dose administration of macrolides has been suggested as a treatment option. The MACS (Macrolides in chronic rhinosinusitis) study is a randomized placebo‐controlled trial evaluating the efficacy of azithromycin (AZM) in CRS.
Methods: We describe a group of patients with recalcitrant CRS with and without nasal polyps unresponsive to optimal medical and (in 92% also) surgical treatment. Patients were treated with AZM or placebo. AZM was given for 3 days at 500 mg during the first week, followed by 500 mg per week for the next 11 weeks. Patients were monitored until 3 months post‐therapy. The assessments included Sino‐Nasal Outcome Test‐22 (SNOT‐22), a Patient Response Rating Scale, Visual Analogue Scale (VAS), Short Form‐36 (SF‐36), rigid nasal endoscopy, peak nasal inspiratory flow (PNIF), Sniffin’ Sticks smell tests and endoscopically guided middle meatus cultures.
Results: Sixty patients with a median age of 49 years were included. Fifty per cent had asthma and 58% had undergone revision sinus surgery. In the SNOT‐22, Patient Response Rating Scale, VAS scores and SF‐36, no significant difference between the AZM and the placebo groups was demonstrated. Nasal endoscopic findings, PNIF results, smell tests and microbiology showed no relevant significant differences between the groups either.
Conclusion: At the investigated dose of AZM over 3 months, no significant benefit was found over placebo. Possible reasons could be disease severity in the investigated group, under‐dosage of AZM and under‐powering of the study. Therefore, more research is urgently required.
Production of apoplastic reactive oxygen species (ROS), or oxidative burst, is among the first responses of plants upon recognition of microorganisms. It requires peroxidase or NADPH oxidase (NOX) ...activity and factors maintaining cellular redox homeostasis. Here, PpTSPO1 involved in mitochondrial tetrapyrrole transport and abiotic (salt) stress tolerance was tested for its role in biotic stress in Physcomitrella patens, a nonvascular plant (moss). The fungal elicitor chitin caused an immediate oxidative burst in wild-type P. patens but not in the previously described ΔPrx34 mutants lacking the chitin-responsive secreted class III peroxidase (Prx34). Oxidative burst in P. patens was associated with induction of the oxidative stress-related genes AOX, LOX7, and NOX, and also PpTSPO1. The available ΔPpTSPO1 knockout mutants overexpressed AOX and LOX7 constitutively, produced 2.6-fold more ROS than wild-type P. patens, and exhibited increased sensitivity to a fungal necrotrophic pathogen and a saprophyte. These results indicate that Prx34, which is pivotal for antifungal resistance, catalyzes ROS production in P. patens, while PpTSPO1 controls redox homeostasis. The capacity of TSPO to bind harmful free heme and porphyrins and scavenge them through autophagy, as shown in Arabidopsis under abiotic stress, seems important to maintenance of the homeostasis required for efficient pathogen defense.
Fine-scaled genetic structuring, as seen for example in many lacustrine fish, typically relates to the patterns of migration, habitat use, mating system or other ecological factors. Because the same ...processes can also affect the propensity of population differentiation and divergence, assessments of species from rapidly speciating clades, or with particularly interesting ecological traits, can be especially insightful. For this study, we assessed the spatial genetic relationships, including the genetic evidence for sex-biased dispersal, in a colony-breeding cichlid fish, Amphilophus astorquii, endemic to Crater Lake Apoyo in Nicaragua, using 11 polymorphic microsatellite loci (n = 123 individuals from three colonies). We found no population structure in A. astorquii either within colonies (no spatial genetic autocorrelation, r ~0), or at the lake-wide level (pairwise population differentiation F
= 0-0.013 and no clustering), and there was no sex-bias (male and female AIc values bounded 0) to this lack of genetic structure. These patterns may be driven by the colony-breeding reproductive behaviour of A. astorquii. The results suggest that strong philopatry or spatial assortative mating are unlikely to explain the rapid speciation processes associated with the history of this species in Lake Apoyo.
Summary It has been proposed that an epithelial injury may be one of the multiple primary events in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The aim of this study was to characterize ...the tight junction and adherens junction proteins in normal human lung, IPF, cryptogenic organizing pneumonia, and asbestosis. We determined the immunohistochemical cell-specific expression of tight junction proteins claudin-1, claudin-2, claudin-3, claudin-4, claudin-5, and claudin-7, as well as 3 adherens junction proteins, E-cadherin, N-cadherin, and β -catenin. We further analyzed the expression of claudin-1, claudin-3, and claudin-4 and E-cadherin, N-cadherin, and β -catenin at the transcriptional level by quantitative real-time reverse transcriptase polymerase chain reaction. The expression levels of both tight junction and adherens junction proteins were elevated in regenerative alveolar epithelium in pulmonary fibrosis as compared with the expression of these proteins in normal alveolar epithelium. In particular, the expression levels of claudins-1 and claudin-3 were clearly elevated in all diseases. Furthermore, the amounts of adherens junction proteins messenger RNAs (mRNAs) were also all increased in pulmonary fibroses in comparison with healthy controls, with N-cadherin showing the greatest increase in mRNA levels in all diseases. However, the amounts of claudin-1, claudin-3, and claudin-4 mRNAs in fibrotic lung were similar to or even lower than those measured in the healthy controls. It is possible that the diminished capacity to produce claudin mRNAs may be one explanation for poor repair capacity of alveolar epithelial cells in IPF.
The evolution and maintenance of colour polymorphisms remains a topic of considerable research interest. One key mechanism thought to contribute to the coexistence of different colour morphs is a ...bias in how conspicuous they are to visual predators. Although individuals of many species camouflage themselves against their background to avoid predation, differently coloured individuals within a species may vary in their capacity to do so. However, to date, very few studies have explicitly investigated the ability of different colour morphs to plastically adjust their colouration to match their background. The red devil (Amphilophus labiatus) is a Neotropical cichlid fish with a stable colour polymorphism, with the gold morph being genetically dominant and having a myriad of documented advantages over the dark morph. However, gold individuals are much rarer, which may be related to their heightened conspicuousness to would‐be predators. Here, we tested the ability of differently coloured individuals to phenotypically adjust the shade of their body colour and patterns to match their background. In particular, we filmed dark, gold and mottled (a transitioning phase from dark to gold) individuals under an identical set‐up on light vs. dark‐coloured substrates. We found that, in contrast to individuals of the dark morph, gold and mottled individuals were less capable of matching their body colouration to their background. As a result, gold individuals appeared to be more conspicuous. These results suggest that a difference in background matching ability could play an important role in the maintenance of colour polymorphisms.
Aim
The extralevator abdominoperineal excision (ELAPE) has been expected to reduce the risk of positive circumferential resection margins (CRMs) and local recurrence in locally advanced distal rectal ...cancer. The aim was to determine whether there is any difference in local recurrence rates between patients who were operated on for distal rectal cancer before and after the introduction of ELAPE in our unit.
Patients and methods
In all, 206 patients with distal rectal cancer without distant metastases (T1‐4N0‐2M0) were treated with curative intent. The patients were divided into two cohorts operated in 2000–2007 (A) and 2008–2014 (B). The ELAPE procedure was introduced in 2008. Since then, it has been used in cases of T4 and T3 tumours with threatened margins. In T1–T3 tumours without threatened margins a conventional abdominal perineal excision has been performed.
Results
There was no significant difference in overall survival or cancer‐specific survival between the two time periods. The local recurrence rate was 15.5% in group A and 6.7% in group B (P = 0.048), although there was no significant difference in the cumulative local recurrence rate. Intra‐operative tumour perforation occurred significantly more often during the earlier period when ELAPE was not in use: group A 15/71 (21.1%) vs group B 11/135 (8.1%), P = 0.01. CRM was positive more often in group A (16.4%) vs group B (7.4%), P = 0.054.
Conclusion
The local recurrence rate, intra‐operative tumour perforation and positive CRM rate were significantly lower during the later period when more extensive surgery (ELAPE) was performed for locally advanced T3–T4 rectal cancer with threatened margins.
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