Arabidopsis CULLIN3 Genes Regulate Primary Root Growth and Patterning by Ethylene-Dependent and -Independent Mechanisms

CULLIN3 (CUL3) together with BTB-domain proteins form a class of Cullin-RING ubiquitin ligases (called CRL3s) that control the rapid and selective degradation of important regulatory proteins in all eukaryotes. Here, we report that in the model plant Arabidopsis thaliana, CUL3 regulates plant growth and development, not only during embryogenesis but also at post-embryonic stages. First, we show that CUL3 modulates the emission of ethylene, a gaseous plant hormone that is an important growth regulator. A CUL3 hypomorphic mutant accumulates ACS5, the rate-limiting enzyme in ethylene biosynthesis and as a consequence exhibits a constitutive ethylene response. Second, we provide evidence that CUL3 regulates primary root growth by a novel ethylene-dependant pathway. In particular, we show that CUL3 knockdown inhibits primary root growth by reducing root meristem size and cell number. This phenotype is suppressed by ethylene-insensitive or resistant mutations. Finally, we identify a function of CUL3 in distal root patterning, by a mechanism that is independent of ethylene. Thus, our work highlights that CUL3 is essential for the normal division and organisation of the root stem cell niche and columella root cap cells

Effects of long-term continuous positive airway pressure on body composition and IGF1

OBJECTIVE: To investigate the long-term effects of nasal continuous positive airway pressure (CPAP) ventilation in patients with obstructive sleep apnea syndrome (OSAS) on body composition (BC) and IGF1. DESIGN: Observational study. SUBJECTS: Seventy-eight (11 females and 67 males) OSAS patients who were compliant with CPAP (age 51+/-1.1 years) participated in the study. We assessed body mass index (BMI), total body mass (TBM), total body fat (TBF; kg) and lean body mass (LBM; kg), abdominal subcutaneous (SC) and visceral (V) fat (cm(2)), and waist circumference (WC; cm) by magnetic resonance imaging, and IGF1 (ng/ml) before and after 7.8+/-1.3 months of CPAP use of an average of 5.9+/-1.2 h. RESULTS: Women had a higher BMI, WC; TBM, TBF, and more SC fat. Men had a higher LBM and more V fat. CPAP increased WC (+2.8+/-9.6 cm, P=0.02) and LBM (2.2+/-0.5 kg, P=0.006), but not IGF1. In men, CPAP increased BMI (0.5+/-0.2 kg/m(2), P=0.02), WC (1.7+/-6.9 cm, P=0.002), TBM (1.7+/-0.4 kg, P=0.0001), LBM (1.5+/-0.4 kg, P=0.0003), SC fat (12.9+/-5.1 cm(2), P=0.02), and IGF1 (13.6+/-4.2 ng/ml, P=0.002). Compliance with CPAP increased LBM in men aged 60 years, and IGF1 increased in men aged 40-60 years only. CONCLUSIONS: Long-term CPAP increased LBM in both sexes and IGF1 in men, while fat mass remained unchanged, suggesting a sexually dimorphic response of IGF1 to CPAP. The role of the GH axis activity and age to this response is unclear. The metabolic consequences of changes in LBM are still to be determined. Future studies on the effects of CPAP on BC should include LBM as an outcome

MÖSSBAUER SPECTRA OF I129 IN TOBACCO MOSAIC VIRUS

A l'aide des isotopes I129 fixés au virus mosaïque de tabac, on peut effectuer des études par spectroscopie Mössbauer qui fournissent des informations sur la structure quaternaire de cette molécule. En ce qui concerne leurs liaisons chimiques, des mesures de la constante d'interaction quadrupolaire ont été réalisées aux amino-acides tyrosine 139 et cystéine 27 contenus dans le virus mosaique de tabac. Le paramètre de ces expériences est la valeur pH. Les résultats prouvent l'existence d'une liaison d'hydrogène dans le virus provenant du groupe hydroxyle de la tyrosine 139 et excluent la présence d'une liaison de cystine s'appuyant sur la cystéine 27.The observation of the electric quadrupole coupling constant of I129 in tobacco mosaic virus provides data related to the quaternary structure of the molecule. To obtain information on their chemical bonds the amino acids tyrosine 139 and cysteine 27 in tobacco mosaic virus were iodinated and the Mössbauer spectra of the samples were measured at various pH-values. The results prove the existence of a hydrogen bond involving the hydroxyl group of tyrosine 139, and exclude the formation of a cystine bridge at cysteine 27 in tobacco mosaic virus

A census of breeding Manx shearwaters on the Pembrokeshire Islands of Skomer, Skokholm and Midland in 2018

We present the results of a census of the Manx Shearwaters Puffinus puffinus nesting on the three Pembrokeshire islands of Skomer, Skokholm and Midland (formerly Middleholm), Pembrokeshire, undertaken in 2018. The breeding population estimates were largely in line with those made in 2011-2013, but differed markedly from 1998; this difference seems to be due to the different methods used in 1998 rather than any marked change in population size. Despite attempts to refine the estimation of response rate to call playback, the error of the population estimates remains large, illustrating the logistical and analytical challenges of making seabird censuses using call playback. Nonetheless, the population estimates are large and the spatial distribution of occupied burrows is consistent between censuses, and thus Wales may hold more than half of the world’s breeding population of Manx Shearwaters