THE OPEN CONDUPLICATE CARPEL OF AKEBIA QUINATA (BERBERIDALES: LARDIZABALACEAE)

Anatomical studies of the carpel of Akebia quinata Decaisne show that it is open at the apex. This carpel is interpreted in this study as a primitively unsealed, conduplicate megasporophyll of the type that is well known among such primitive ranalean genera as Drimys, Bubbia, Degeneria, Schisandra, etc. This interpretation is complemented by other primitive character states of the Akebia flower and carpel, including free organs, laminar stamens, an only slightly modified stigmatic crest, laminal placentation of the many ovules, suture-like closure of the ovary wall below the stigmatic crest, and maturation of the carpel to produce a moist, dehiscent follicle. These features indicate relative primitiveness of the Lardizabalaceae among the families of the Berberidales.     

Reversible colour change in Arthropoda

The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross‐disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry.     

Environmental effects on the maturation of the endodermis and multiseriate exodermis of Iris germanica roots

Background and Aims

Most studies of exodermal structure and function have involved species with a uniseriate exodermis. To extend this work, the development and apoplastic permeability of Iris germanica roots with a multiseriate exodermis (MEX) were investigated. The effects of different growth conditions on MEX maturation were also tested. In addition, the exodermises of eight Iris species were observed to determine if their mature anatomy correlated with habitat.

Methods

Plants were grown in soil, hydroponics (with and without a humid air gap) or aeroponics. Roots were sectioned and stained with various dyes to detect MEX development from the root apical meristem, Casparian bands, suberin lamellae and tertiary wall thickenings. Apoplastic permeability was tested using dye (berberine) and ionic (ferric) tracers.

Key Results

The root apical meristem was open and MEX development non-uniform. In soil-grown roots, the exodermis started maturing (i.e. Casparian bands and suberin lamellae were deposited) 10 mm from the tip, and two layers had matured by 70 mm. In both hydro- and aeroponically grown roots, exodermal maturation was delayed. However, in areas of roots exposed to an air gap in the hydroponic system, MEX maturation was accelerated. In contrast, maturation of the endodermis was not influenced by the growth conditions. The mature MEX had an atypical Casparian band that was continuous around the root circumference. The MEX prevented the influx and efflux of berberine, but had variable resistance to ferric ions due to their toxic effects. Iris species living in well-drained soils developed a MEX, but species in water-saturated substrates had a uniseriate exodermis and aerenchyma.

Conclusions

MEX maturation was influenced by the roots'' growth medium. The MEX matures very close to the root tip in soil, but much further from the tip in hydro- and aeroponic culture. The air gap accelerated maturation of the second exodermal layer. In Iris, the type of exodermis was correlated with natural habitat suggesting that a MEX may be advantageous for drought tolerance.Key words: Iris germanica, roots, culture conditions, development, anatomy, apoplastic tracers, multiseriate exodermis, endodermis, root apical meristem     

Remission in psoriatic arthritis: is it possible and how can it be predicted?

Introduction

Since remission is now possible in psoriatic arthritis (PsA) we wished to examine remission rates in PsA patients following anti tumour necrosis factor alpha (TNFα) therapy and to examine possible predictors of response.

Methods

Analysis of a prospective patient cohort attending a biologic clinic, between November 2004 and March 2008, was performed prior to commencing therapy and at regular intervals. Baseline clinical characteristics including demographics, previous disease-modifying antirheumatic drug (DMARD) response, tender and swollen joint counts, early morning stiffness, pain visual analogue score, patient global assessment, C reactive protein (CRP) and health assessment questionnaire (HAQ) were collected.

Results

A total of 473 patients (152 PsA; 321 rheumatoid arthritis (RA)) were analyzed. At 12 months remission, defined according to the disease activity score using 28 joint count and CRP (DAS28-CRP), was achieved in 58% of PsA patients compared to 44% of RA patients, significant improvement in outcome measures were noted in both groups (P < 0.05). Analysis of a subgroup of PsA and RA patients matched for DAS28-CRP at baseline also showed higher numbers of PsA patients achieving remission. Linear regression analysis identified the HAQ at baseline as the best predictor of remission in PsA patients (P < 0.001).

Conclusions

DAS28 remission is possible in PsA patients at one year following anti-TNF therapy, at higher rates than in RA patients and is predicted by baseline HAQ.     

Root and stem anatomy and histochemistry of four grasses from the Jianghan Floodplain along the Yangtze River, China

The present study examined anatomical and histochemical features of belowground axes of four grass species (Cynodon dactylon, Eremochloa ophiuroides, Hemerthria altissima, and Paspalum distichum) which occur in wetlands and can survive flooding. They may help to restore the degraded ecological environment of the floodplain in the Jianghan Plain and the Three Gorges Dam riparian zone of the Yangtze River, China. Brightfield and epifluorescence microscopy gave evidence that the roots of the four species share similar structures with each having endodermis and exodermis, with mostly Y-shaped Casparian walls, suberin lamellae, and lignified secondary cell walls. But the timing of wall deposit apposition and the degree of secondary thickening vary among the species. The root cortical aerenchyma is basically lysigenous. Rhizomes and stolons have an epidermis with thick cuticle, a peripheral, mechanically stiff ring with or without small embedded vascular bundles and a chlorenchyma. The cortex is of varying thickness, with or without collenchymas. A central core of vascular bundles is usually surrounded by a sclerenchyma ring of varying thickness, depending upon the species. Pith cavities and small cortical cavities are normal except for unusual honeycomb or expansigenous aerenchyma in one species. The peripheral mechanical ring and the sclerenchyma ring contain suberin and lignin, but no detectable Casparian bands. Even in non-flooded conditions, anatomical traits of these species provide adaptive features allowing them to occupy riparian zones as they occur at the Yangtze River.     

Phylogeny, classification and evolution of ladybird beetles (Coleoptera: Coccinellidae) based on simultaneous analysis of molecular and morphological data

Ladybird beetles (family Coccinellidae) are a species-rich, ecologically diverse group of substantial agricultural significance, yet have been consistently problematic to classify, with evolutionary relationships poorly understood. In order to identify major clades within Coccinellidae, evaluate the current classification system, and identify likely drivers of diversification in this polyphagous group, we conducted the first simultaneous Bayesian analysis of morphological and multi-locus molecular data for any beetle family. Addition of morphological data significantly improved phylogenetic resolution and support for early diverging lineages, thereby better resolving evolutionary relationships than either data type alone. On the basis of these results, we formally recognize the subfamilies Microweisinae and Coccinellinae sensu?lipiński (2007). No significant support was found for the subfamilies Coccidulinae, Scymninae, Sticholotidinae, or Ortaliinae. Our phylogenetic results suggest that the evolutionary success of Coccinellidae is in large part attributable to the exploitation of ant-tended sternorrhynchan insects as a food source, enabled by the key innovation of unusual defense mechanisms in larvae.