Flexible control of plant architecture and yield via switchable expression of Arabidopsis gai

The growth of plants is repressed by DELLA proteins, nuclear regulators whose activities are opposed by the growth-promoting phytohormone gibberellin (GA). Mutations affecting DELLA protein function were previously used by plant breeders to create the high-yielding semidwarf wheat varieties of the green revolution. gai is an Arabidopsis mutant DELLA protein-encoding orthologue of the wheat semidwarfing genes. Here we describe the development of a transgene that confers ethanol-inducible gai expression. Transient induction of gai causes transient growth repression: growth prior to and after treatment is unaffected. Appropriate ethanol treatments result in dwarf plants that produce the same numbers of seeds as untreated controls. This new technology represents a substantial advance in the applicability of genes encoding mutant DELLA proteins to agricultural and horticultural improvement, enhancing the flexibity with which these genes can be used for the sustainable achievement of increased crop plant yields.     

Morphometric analysis of six Gerbillus species (Rodentia,Gerbillinae) from Tunisia

Size and shape changes in the skull of the genus Gerbillus were investigated using geometric morphometrics. Six species from Tunisia were studied (G. gerbillus, G. campestris, G. nanus, G. tarabuli, G. simoni and G. latastei). Statistical analyses of shape variability allowed us to discriminate three morphological groups which are congruent with the three groups suggested by previous morphological and molecular studies. However, our results contrast with previous molecular investigations. In fact, according to results obtained by the use of principal component analysis, canonical variate analysis and UPGMA, we found a higher degree of divergence between the subgenus Dipodillus and the other two subgenera Gerbillus and Hendecapleura. This fact suggests that the morphometric differences observed among species within the genus Gerbillus are not mainly related to phylogeny. To reconciliate the molecular and morphological approaches, we propose a hypothesis of differential rates of phenotypic evolution in the genus Gerbillus. In this view, the species belonging to the subgenus Dipodillus evolved apomorphic features of the skull likely related to a higher degree of habitat specialization. By contrast, the more generalist Gerbillus and Hendecapleura subgenera show less differentiated plesiomorphic morphology.     

Sulfate reduction from phosphogypsum using a mixed culture of sulfate-reducing bacteria

Phosphogypsum (CaSO₄), a primary by-product of phosphoric acid production, is accumulated in large stockpiles and occupies vast areas of land. It poses a severe threat to the quality of water and land in countries producing phosphoric acid. In this study, the potential of sulfate-reducing bacteria for biodegradation of this sulfur-rich industrial solid waste was assessed. The effect of phosphogypsum concentration, carbon and nitrogen sources, temperature, pH and stirring on the growth of sulfate-reducing bacteria was investigated. Growth of sulfate-reducing bacteria was monitored by measuring sulfide production. Phosphogypsum was shown to be a good source of sulfate, albeit that the addition of organic carbon was necessary for bacterial growth. Biogenic sulfide production occurred with phosphogypsum up to a concentration of 40 g L⁻¹, above which no growth of sulfate-reducing bacteria was observed. Optimal growth was obtained at 10 g L⁻¹ phosphogypsum. Both the gas mixture H₂/CO₂ and lactate supported high amounts of H₂S formation (19 and 11 mM, respectively). The best source of nitrogen for sulfate-reducing bacteria was yeast extract, followed by ammonium chloride. The presence of nitrate had an inhibitory effect on the process of sulfate reduction. Stirring the culture at 150 rpm slightly stimulated H₂S formation, probably by improving sulfate solubility.     

Effect of Growth Stage on Essential‐Oil Yield and Composition of Daucus sahariensis

The essential oils obtained by hydrodistillation from Daucus sahariensis Murb . harvested at three different growth stages were characterized by GC/MS analysis. In total, 88 compounds were identified, with myristicin (29.8–51.7%), myrcene (6.7–31.1%), α‐pinene (11.6–14.8%), and limonene (5.3–11.5%) as main constituents. Monoterpene hydrocarbons were the most represented compounds in the oils of the plant samples collected during the flower‐budding and full‐flowering periods. On the contrary, during the fruiting stage, the oils were dominated by phenylpropanoids. The essential oils were subject of considerable variation in their composition during the various developmental stages, particularly concerning the content of myrcene that decreased significantly passing from the vegetative to the fruiting stage. Conversely, for myristicin, the opposite trend was observed. Furthermore, the essential‐oil yields were quite low during the flower‐budding phase (0.27%), but rapidly increased during plant development (0.63 and 0.68% for the flowering and fruiting phases, resp.).     

Regulation of adiponectin production by insulin: interactions with tumor necrosis factor-α and interleukin-6

Obesity is often associated with insulin resistance, low-grade systemic inflammation, and reduced plasma adiponectin. Inflammation is also increased in adipose tissue, but it is not clear whether the reductions of adiponectin levels are related to dysregulation of insulin activity and/or increased proinflammatory mediators. In this study, we investigated the interactions of insulin, tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) in the regulation of adiponectin production using in vivo and in vitro approaches. Plasma adiponectin and parameters of insulin resistance and inflammation were assessed in a cohort of lean and obese insulin-resistant subjects. In addition, the effect of insulin was examined in vivo using the hyperinsulinemic-euglycemic clamp, and in adipose tissue (AT) cultures. Compared with lean subjects, the levels of total adiponectin, and especially the high-molecular-weight (HMW) isomer, were abnormally low in obese insulin-resistant subjects. The hyperinsulinemic clamp data confirmed the insulin-resistant state in the obese patients and showed that insulin infusion significantly increased the plasma adiponectin in lean but not obese subjects (P < 0.01). Similarly, insulin increased total adiponectin release from AT explants of lean and not obese subjects. Moreover, expression and secretion of TNF-α and IL-6 increased significantly in AT of obese subjects and were negatively associated with expression and secretion of adiponectin. In 3T3-L1 and human adipocyte cultures, insulin strongly enhanced adiponectin expression (2-fold) and secretion (3-fold). TNF-α, and not IL-6, strongly opposed the stimulatory effects of insulin. Intriguingly, the inhibitory effect of TNF-α was especially directed toward the HMW isomer of adiponectin. In conclusion, these studies show that insulin upregulates adiponectin expression and release, and that TNF-α opposes the stimulatory effects of insulin. A combination of insulin resistance and increased TNF-α production could explain the decline of adiponectin levels and alterations of isomer composition in plasma of obese insulin-resistant subjects.     

Fluorescence Spectroscopy as a Promising Tool for a Polyphasic Approach to Pseudomonad Taxonomy

Fluorescence spectroscopy is an emerging tool for the analysis of biomolecules from complex matrices. We explored the potentialities of the method for the pseudomonad taxonomic purpose at the genus and species level. Emission spectra of three intrinsic fluorophores (namely, NADH, tryptophan, and the complex of aromatic amino acids and nucleic acid) were collected from whole bacterial cells. Their comparisons were performed through principal component analysis and factorial discriminant analysis. Reference strains from the Xanthomonas, Stenotrophomonas, Burkholderia, and Pseudomonas genera were well separated, with sensitivity and selectivity higher than 90%. At the species level, P. lundensis, P. taetrolens, P. fragi, P. chlororaphis, and P. stutzeri were also well separated, in a distant group, from P. putida, P. pseudoalcaligenes, and P. fluorescens. These results are in agreement with the generally admitted rRNA and DNA bacterial homology grouping but they also provide additional information about strain relatedness. In the case of environmental isolates, the method allows good discrimination, even for strains for which ambiguity still remained after PCR and API 20NE identification. Rapid, easy to perform, and low cost, fluorescence spectroscopy provides substantial information on cell components. Statistical analysis of collected data allows in-depth comparison of strains. Our results strongly support the view that fluorescence spectroscopy fingerprinting can be used as a powerful tool in a polyphasic approach to pseudomonad taxonomy.     

Long-Term Tinnitus Suppression with Linear Octave Frequency Transposition Hearing Aids

Over the last three years of hearing aid dispensing, it was observed that among 74 subjects fitted with a linear octave frequency transposition (LOFT) hearing aid, 60 reported partial or complete tinnitus suppression during day and night, an effect still lasting after several months or years of daily use. We report in more details on 38 subjects from whom we obtained quantified measures of tinnitus suppression through visual analog scaling and several additional psychoacoustic and audiometric measures. The long-term suppression seems independent of subject age, and of duration and subjective localization of tinnitus. A small but significant correlation was found with audiogram losses but not with high frequency loss slope. Long-term tinnitus suppression was observed for different etiologies, but with a low success rate for sudden deafness. It should be noted that a majority of subjects (23) had a history of noise exposure. Tinnitus suppression started after a few days of LOFT hearing aid use and reached a maximum after a few weeks of daily use. For nine subjects different amounts of frequency shifting were tried and found more or less successful for long-term tinnitus suppression, no correlation was found with tinnitus pitch. When the use of the LOFT hearing aid was stopped tinnitus reappeared within a day, and after re-using the LOFT aid it disappeared again within a day. For about one third of the 38 subjects a classical amplification or a non linear frequency compression aid was also tried, and no such tinnitus suppression was observed. Besides improvements in audiometric sensitivity to high frequencies and in speech discrimination scores, LOFT can be considered as a remarkable opportunity to suppress tinnitus over a long time scale. From a pathophysiological viewpoint these observations seem to fit with a possible re-attribution of activity to previously deprived cerebral areas corresponding to high frequency coding.     

TCTN3 Mutations Cause Mohr-Majewski Syndrome

Orofaciodigital syndromes (OFDSs) consist of a group of heterogeneous disorders characterized by abnormalities in the oral cavity, face, and digits and associated phenotypic abnormalities that lead to the delineation of 13 OFDS subtypes. Here, by a combined approach of homozygozity mapping and exome ciliary sequencing, we identified truncating TCTN3 mutations as the cause of an extreme form of OFD associated with bone dysplasia, tibial defect, cystic kidneys, and brain anomalies (OFD IV, Mohr-Majewski syndrome). Analysis of 184 individuals with various ciliopathies (OFD, Meckel, Joubert, and short rib polydactyly syndromes) led us to identify four additional truncating TCTN3 mutations in unrelated fetal cases with overlapping Meckel and OFD IV syndromes and one homozygous missense mutation in a family with Joubert syndrome. By exploring roles of TCTN3 in human ciliary related functions, we found that TCTN3 is necessary for transduction of the sonic hedgehog (SHH) signaling pathway, as revealed by abnormal processing of GLI3 in patient cells. These results are consistent with the suggested role of its murine ortholog, which forms a complex at the ciliary transition zone with TCTN1 and TCTN2, both of which are also implicated in the transduction of SHH signaling. Overall, our data show the involvement of the transition zone protein TCTN3 in the regulation of the key SHH signaling pathway and that its disruption causes a severe form of ciliopathy, combining features of Meckel and OFD IV syndromes.