A GRAS-like gene of sunflower (Helianthus annuus L.) alters the gibberellin content and axillary meristem outgrowth in transgenic Arabidopsis plants.

The GRAS proteins belong to a plant transcriptional regulator family that function in the regulation of plant growth and development. Despite their important roles, in sunflower only one GRAS gene (HaDella1) with the DELLA domain has been reported. Here, we provide a functional characterisation of a GRAS-like gene from Helianthus annuus (Ha-GRASL) lacking the DELLA motif. The Ha-GRASL gene contains an intronless open reading frame of 1,743 bp encoding 580 amino acids. Conserved motifs in the GRAS domain are detected, including VHIID, PFYRE, SAW and two LHR motifs. Within the VHII motif, the P-H-N-D-Q-L residues are entirely maintained. Phylogenetic analysis reveals that Ha-GRASL belongs to the SCARECROW LIKE4/7 (SCL4/7) subfamily of the GRAS consensus tree. Accumulation of Ha-GRASL mRNA at the adaxial boundaries from P6/P7 leaf primordia suggests a role of Ha-GRASL in the initiation of median and basal axillary meristems (AMs) of sunflower. When Ha-GRASL is over-expressed in Arabidopsis wild-type plants, the number of lateral bolts increases differently from untransformed plants. However, Ha-GRASL slightly affects the lateral suppressor (las-4-) mutation. Therefore, we hypothesise that Ha-GRASL and LAS are not functionally equivalent. The over-expression of Ha-GRASL reduces metabolic flow of gibberellins (GAs) in Arabidopsis and this modification could be relevant in AM development. Phylogenetic analysis includes LAS and SCL4/7 in the same major clade, suggesting a more recent separation of these genes with respect to other GRAS members. We propose that some features of their ancestor, as well as AM initiation and outgrowth, are partially retained in both LAS and SCL4/7.

Regulatory interplay of the Sub1A and CIPK15 pathways in the regulation of α-amylase production in flooded rice plants.

Rice (Oryza sativa L.) can successfully germinate and grow even when flooded. Rice varieties possessing the submergence 1A (Sub1A) gene display a distinct flooding-tolerant phenotype, associated with lower carbohydrate consumption and restriction of the fast-elongation phenotype typical of flooding-intolerant rice varieties. Calcineurin B-like interacting protein kinase 15 (CIPK15) was recently indicated as a key regulator of α-amylases under oxygen deprivation, linked to both rice germination and flooding tolerance in adult plants. It is still unknown whether the Sub1A- and CIPK15-mediated pathways act as complementary processes for rice survival under O(2) deprivation. In adult plants Sub1A and CIPK15 may perhaps play an antagonistic role in terms of carbohydrate consumption, with Sub1A acting as a starch degradation repressor and CIPK15 as an activator. In this study, we analysed sugar metabolism in the stem of rice plants under water submergence by selecting cultivars with different traits associated with flooding survival. The relation between the Sub1A and the CIPK15 pathways was investigated. The results show that under O(2) deprivation, the CIPK15 pathway is repressed in the tolerant, Sub1A-containing, FR13A variety. CIPK15 is likely to play a role in the up-regulation of Ramy3D in flooding-intolerant rice varieties that display fast elongation under flooding and that do not possess Sub1A.

Distinct mechanisms for aerenchyma formation in leaf sheaths of rice genotypes displaying a quiescence or escape strategy for flooding tolerance.

BACKGROUND AND AIMS: Rice is one of the few crops able to withstand periods of partial or even complete submergence. One of the adaptive traits of rice is the constitutive presence and further development of aerenchyma which enables oxygen to be transported to submerged organs. The development of lysigenous aerenchyma is promoted by ethylene accumulating within the submerged plant tissues, although other signalling mechanisms may also co-exist. In this study, aerenchyma development was analysed in two rice (Oryza sativa) varieties, 'FR13A' and 'Arborio Precoce', which show opposite traits in flooding response in terms of internode elongation and survival. METHODS: The growth and survival of rice varieties under submergence was investigated in the leaf sheath of 'FR13A' and 'Arborio Precoce'. The possible involvement of ethylene and reactive oxygen species (ROS) was evaluated in relation to aerenchyma formation. Cell viability and DNA fragmentation were determined by FDA/FM4-64 staining and TUNEL assay, respectively. Ethylene production was monitored by gas chromatography and by analysing ACO gene expression. ROS production was measured by using Amplex Red assay kit and the fluorescent dye DCFH(2)-DA. The expression of APX1 was also evaluated. AVG and DPI solutions were used to test the effect of inhibiting ethylene biosynthesis and ROS production, respectively. KEY RESULTS: Both the varieties displayed constitutive lysigenous aerenchyma formation, which was further enhanced when submerged. 'Arborio Precoce', which is characterized by fast elongation when submerged, showed active ethylene biosynthetic machinery associated with increased aerenchymatous areas. 'FR13A', which harbours the Sub1A gene that limits growth during oxygen deprivation, did not show any increase in ethylene production after submersion but still displayed increased aerenchyma. Hydrogen peroxide levels increased in 'FR13A' but not in 'Arborio Precoce'. CONCLUSIONS: While ethylene controls aerenchyma formation in the fast-elongating 'Arborio Precoce' variety, in 'FR13A' ROS accumulation plays an important role.

Correlation between faecal calprotectin and magnetic resonance imaging (MRI) in the evaluation of inflammatory pattern in Crohn's disease.

BACKGROUND: Calprotectin, a major cytosolic protein of neutrophils, is increased in inflammatory bowel disease (IBD) and may be considered a suitable marker of intestinal inflammation. Abdominal MRI is becoming more frequently used for the evaluation of IBD patients. Aim of this study was to investigate the role of MRI in IBD for the assessment of disease activity in comparison with faecal calprotectin levels. PATIENTS AND METHODS: Twenty-four consecutive hospitalized pts (12 F, 12 M, median age: 56; range: 22-77) with a proven diagnosis of CD were studied. At the time of the MRI examination, pts provided a single stool sample for calprotectin measurement. Calprotectin was measured by ELISA (Calprest(R)). Pathological values were considered more than 50 microg/g. All pts underwent MRI, performed at 1.5 T, with HASTE T2w with and without fat-saturation, FLASH T1w fat-saturated sequences pre and post iv injection of 0.1 ml/kg of Gadolinium. Presence, degree and length of wall inflammation were evaluated. The MRI degree of wall inflammation was graded with a 0-3 scoring system (0=absent 1=light 2=moderate 3=severe) by considering findings observed on T1 post Gd and T2 fat-suppressed images, as well as the degree of wall thickness. The length of extension was considered as less than 15 cm, between 15 cm and 30 cm, or more than 30 cm. Spearman's correlation coefficient was used to evaluated differences in calprotectin levels among the groups obtained by MRI findings. RESULTS: Grade 0 MRI was found in 1 pt with a faecal calprotectin measurement of 206.25 microg/g; Grade 1 MRI was found in 4 pts with a median faecal calprotectin of 100 microg/g (5-325); Grade 2 MRI was found in 10 pts with a median faecal calprotectin of 243.75 microg/g (7.5-606.25); Grade 3 MRI was found in 9 pts with a median faecal calprotectin of 1012.5 microg/g (30-1268.8). A trend of positive correlation was therefore found between MRI scores of activity and calprotectin levels (p less than 0.0001) and between MRI scores of thickening of intestinal involvement and calprotectin levels (p = 0.005). No apparent correlation was observed between faecal calprotectin concentration and length. CONCLUSIONS: Data presenting show that faecal calprotectin levels well correlate with the degree of mucosal inflammation are in agreement with previous studies. Considering the correlation obtained between calprotectin level and MRI findings, we believe that MRI is helpful in assessing and monitoring the degree of disease in Crohn's disease.

Diffuse abdominal hydatidosis: role of magnetic resonance imaging.

Hydatid cyst disease still is a serious public-health problem in endemic areas. It is a tissue infestation caused by the larval stage of a parasite, Echinococcus granulosus. Although liver and lung are the most commonly involved organs, hydatid disease can occur in all viscera and soft tissues. In 10% of cases, hydatid disease arises in the viscera: mainly in the spleen (0.9-8%), but also in kidney, bone, heart and peritoneal cavity (0.5-5%). Other rare locations such as muscles have been described in less than 1% of cases of hydatid disease. We report magnetic resonance imaging findings of a case of diffuse abdominal hydatidosis.

Ulcerative colitis: value of MR imaging.

Recent technologic advances have greatly improved the quality of abdominal magnetic resonance imaging (MRI) by allowing the identification of abnormalities in inflammatory bowel disease. Thus far, the role of MRI has been extensively investigated in Crohn disease (CD) and, to a minor extent, in ulcerative colitis (UC), likely due to intrinsic differences between these two diseases. In UC the inflammatory lesions, unlike CD, are confined to the colon, have a predictable spreading, and affect only the inner wall layer; thus endoscopy alone can assess the extent and severity of disease in most cases. However, preliminary studies have demonstrated that MRI also can be a reliable diagnostic tool for UC because it is useful for integrating clinical and endoscopic data. MRI can be valuable in distinguishing CD from UC in uncertain cases by assessing the sparing of the distal ileum and the continuity of colonic involvement. Moreover, MRI can provide important information if endoscopy is incomplete, e.g., due to tight strictures, or contraindicated, e.g., in severely acute disease, due to a high risk of perforation. MRI can detect most of the typical findings of the diseases, such as wall thickening, mural stratification, loss of haustrations, and several complications including fibrotic or neoplastic strictures. In addition, MRI can be extremely valuable in assessing disease activity by monitoring the degree of wall gadolinium enhancement and T2 signal at the level of the affected bowel segments, thus influencing pharmacologic and surgical planning. In the next few years, MRI will likely become the imaging modality of choice in the clinical management of this disease.

Nerve conduction study, electromyography and somatosensory evoked potentials in non-Friedreich early onset cerebellar ataxia. A comparative study with Friedreich's ataxia and late onset cerebellar ataxia.

Electrophysiological findings in 14 patients with non-Friedreich early onset cerebellar ataxia are reported. Nerve conduction studies showed reduction of sensory action potential amplitudes in 7 cases associated in 3 with a decrease of sensory conduction velocities. Six subjects also exhibited a chronic neurogenic pattern to standard needle electromyography. Motor conduction velocities were normal in all cases; only two cases showed an increase in distal motor latencies. Short-latency somatosensory evoked potentials following median nerve stimulation revealed a prolonged central conduction time (N13-N20 interpeak latency) in 7 cases, compatible with supraspinal damage of the somatosensory pathways. These electrophysiological data are compared with those obtained in two reference groups of patients, respectively affected by Friedreich's ataxia and olivo-ponto-cerebellar atrophy.

Cortical projection of putative group Ib afferent fibres from the human forearm.

The possibility was investigated that impulses in group Ib afferents from fore-arm flexors have access to cerebral cortex in man. A long-lasting increase in the threshold (Th) of group Ia afferent fibres from flexor carpi radialis muscle (Fcr) was obtained after prolonged (100 Hz for 20 min) tendon vibration at the wrist. It was assumed that under this condition a weak electrical stimulation of the median nerve at the elbow, insufficient to reactivate Ia fibres because of the rise in their threshold (as verified by the method of homonymous Ia facilitation of Fcr H reflex), engaged Ib fibres only. Peripheral volleys at Erb's point and cerebral cortical potentials to median nerve stimulation at the elbow were evoked before and after prolonged vibration of Fcr. During 10-30 min after the end of vibration, in which homonymous facilitation of Fcr H reflex was abolished, both the ongoing peripheral volley and the cortical responses were markedly reduced with respect to their control values. Recovery to pre-vibration control amplitudes coincided with recovery of Fcr H reflex homonymous facilitation. In order to verify if activity in afferents other than group Ib fibres might contribute to the cortical response after vibration, specially designed experiments were also performed. It is concluded that the cortical wave recorded after 20 min vibration represents the arrival of Ib impulses from flexor carpi radialis to the human cerebral cortex.

Unexpected white matter changes in an early treated PKU case and improvement after dietary treatment.

We report a case of classic phenylketonuria (PKU) treated by dietary restriction until the age of 5 years. At the age of 18 years, she developed anxious-depressive symptoms and deterioration of school performance. Neurophysiological investigations showed changes in VEPs and BAEPs and brain MRI showed white matter abnormalities. The return to a diet low in phenylalanine reduced psychiatric disturbances and reversed neurophysiological and MRI changes. Our data confirm previous observations of white matter involvement in PKU and the utility of lifelong dietary therapy to prevent neurological and/or psychiatric deterioration.

Further evidence of involvement of central and peripheral sensory pathways in olivopontocerebellar atrophy.

We report the electrophysiological findings of the central and peripheral somatosensory pathways in 20 patients with olivopontocerebellar atrophy. Changes in sensory action potentials of the median nerve were observed in 14 patients and consisted of reduced sensory potential amplitudes associated in 10 cases with an increase in distal latencies. Sixteen out of 20 patients also showed changes in somatosensory evoked potentials after stimulation of the median nerve, consisting of decreased amplitude of N13 (13 cases) and N20 (16 cases) components, associated with increased N9-N13 interpeak latency in 9 and N13-N20 in 14 patients. The origin of these alterations is discussed.