Biological function of ;pathogenesis-related' proteins: four PR proteins of tobacco have 1,3-beta-glucanase activity

Three of the ten acidic `pathogenesis-related' (PR) proteins known to accumulate in Nicotiana tabacum cv Samsun NN reacting hypersensitively to tobacco mosaic virus, namely −O, −N and −2, have been shown to have 1,3-β-glucanase (EC 3.2.1.39) activity. By using sera raised against each protein purified to homogeneity close serological relationships have been demonstrated between the three proteins. The same specific sera cross-reacted with a basic protein which is also a 1,3-β-glucanase induced by virus infection and which can be considered as a new basic pathogenesis-related protein of tobacco. Protein PR-O and the basic 1,3-β-glucanase display about the same specific enzymatic activity, i.e. 50-fold and 250-fold higher than specific activities of proteins PR-N and -2 respectively.     

Identification and quantitative analysis of beta-sitosterol oxides in vegetable oils by capillary gas chromatography-mass spectrometry

As vegetable oils and phytosterol-enriched spreads are marketed for frying food or cooking purposes, temperature is one of the most important factors leading to the formation of phytosterol oxides in food matrix. A methodology based on saponification, organic solvent extraction, solid-phase extraction (SPE), followed by mass spectrometric identification and quantitation of beta-sitosterol oxides using capillary gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode was developed and characterized. Relative response factors of six beta-sitosterol oxides, including 7alpha-hydroxy, 7beta-hydroxy, 5,6alpha-epoxy, 5,6beta-epoxy, 7-keto, and 5alpha,6beta-dihydroxysitosterol, were calculated against authentic standards of 19-hydroxycholesterol or cholestanol. Linear calibration data, limit of detection, and sample recoveries during analytical process. Recoveries of these oxidation compounds in spiked samples ranged from 88 to 115%, while relative standard derivation (R.S.D.) values were below 10% in most cases. The analytical method was applied to quantify beta-sitosterol oxides formed in thermal-oxidized vegetable oils which were heated at different temperatures and for varying time periods. Sitosterol oxidation is strikingly higher in sunflower oil relative to olive oil under all conditions of temperature and heating time.     

Why the ovotestis of Helix aspersa is innervated

Although Schmalz described the innervation of the ovotestis in pulmonate snails as early as 1914, no functions have been attributed to it. In H. aspersa, the intestinal nerve branches profusely within the ovotestis and terminates in the walls of the acini and in the sheath surrounding the early portion of the hermaphroditic duct. We found both sensory and motor functions for this innervation. Significantly, there is a tonic sensory discharge generated by the mechanical pressure of growing oocytes, and the level of tonic afferent activity is strongly correlated with the number of ripe oocytes; this is probably a permissive signal that gates ovulation. Tactile stimulation of the ovotestis causes a phasic sensory discharge and a pronounced cardio activation. Also, an efferent discharge is elicited in the ovotestis branch of the intestinal nerve. To study the motor consequences of efferent activity, the ovotestis branch was electrically stimulated. We found that such stimulation evokes peristaltic contractions of the initial portion of the hermaphroditic duct and increases beat frequencies of the cilia that line the interior of the duct. These effects could facilitate the transport of oocytes down the duct. Still other functions of afferent activity are implied by changes in the spontaneous activity of mesocerebral cells following nerve stimulation. Putative sensory neurons and putative motoneurons have been identified in the visceral and right parietal ganglia.     

Efficient Reduction of Iron Oxides by Paenibacillus spp. Strains Isolated from Tropical Soils

The genus Paenibacillus was hardly described as a Fe(III)-reducing agent, only limited to reduce soluble forms or Fe inserted in poorly crystallized structures. In this study, three Paenibacillus strains capable of reducing manganese oxides in addition to iron oxides were isolated from Cameroonian and Brazilian soils. These strains reduced iron minerals from poorly crystallized 2-line ferrihydrite to well-crystallized Al-substituted and pure goethite with a significant production of soluble ferrous iron. These Paenibacillus strains, inhabitants from ferralitic temporarily waterlogged soils, could play an important role in the bioweathering of minerals and metal mobility in soils.     

Numerical response of predators to large variations of grassland vole abundance and long‐term community changes

Voles can reach high densities with multiannual population fluctuations of large amplitude, and they are at the base of predator communities in Northern Eurasia and Northern America. This status places them at the heart of management conflicts wherein crop protection and health concerns are often raised against conservation issues. Here, a 20‐year survey describes the effects of large variations in grassland vole populations on the densities and the daily theoretical food intakes (TFI) of vole predators based on roadside counts. Our results show how the predator community responded to prey variations of large amplitude and how it reorganized with the increase in a dominant predator, here the red fox, which likely negatively impacted hare, European wildcat, and domestic cat populations. This population increase did not lead to an increase in the average number of predators present in the study area, suggesting compensations among resident species due to intraguild predation or competition. Large variations in vole predator number could be clearly attributed to the temporary increase in the populations of mobile birds of prey in response to grassland vole outbreaks. Our study provides empirical support for more timely and better focused actions in wildlife management and vole population control, and it supports an evidence‐based and constructive dialogue about management targets and options between all stakeholders of such socio‐ecosystems.

A 20‐year survey describes the effects of large variations in grassland vole populations on the densities and the daily theoretical food intakes of a vole predator community based on roadside counts. Our results show how the predator community responds to prey variations of large amplitude and how it reorganized with the increase of the red fox, which likely negatively impacted hare, European wildcat, and domestic cat populations.     

The Myriapoda and Onychophora collection (MY) of the Muséum national d’Histoire naturelle (MNHN,Paris)

The Myriapoda and Onychophora collection dataset inventories the occurrence records of the collection of myriapods and onychophorans in the Muséum national d’Histoire naturelle, Paris. The dataset currently consists of 202 lots of onychophorans, representing all of those present, and almost ten thousand (9 795) lots of myriapods, representing 33 to 40% of the MNHN Myriapoda collection. This collection, which is of key historic importance, represents the results of two centuries of myriapod and onychophoran studies. The sources of the collection are worldwide, with a high representation for metropolitan France for the myriapods. None of the occurrences are yet georeferenced. Access to the dataset via the data portals of the MNHN and the GBIF has been made possible through the e-ReColNat project (ANR-11-INBS-0004).The Myriapoda and Onychophora collection of MNHN is actively expanding, hence both the collection and dataset are in continuous growth. The dataset can be accessed through the portals of GBIF at http://www.gbif.org/dataset/3287044c-8c48-4ad6-81d4-4908071bc8db and the MNHN at http://science.mnhn.fr/institution/mnhn/collection/my/item/search/form.     

Multilevel Approach of a 1-Year Program of Dietary and Exercise Interventions on Bone Mineral Content and Density in Metabolic Syndrome – the RESOLVE Randomized Controlled Trial

Background

Weight loss is a public health concern in obesity-related diseases such as metabolic syndrome (MetS). However, restrictive diets might induce bone loss. The nature of exercise and whether exercise with weight loss programs can protect against potential bone mass deficits remains unclear. Moreover, compliance is essential in intervention programs. Thus, we aimed to investigate the effects that modality and exercise compliance have on bone mineral content (BMC) and density (BMD).

Methods

We investigated 90 individuals with MetS who were recruited for the 1-year RESOLVE trial. Community-dwelling seniors with MetS were randomly assigned into three different modalities of exercise (intensive resistance, intensive endurance, moderate mixed) combined with a restrictive diet. They were compared to 44 healthy controls who did not undergo the intervention.

Results

This intensive lifestyle intervention (15–20 hours of training/week + restrictive diet) resulted in weight loss, body composition changes and health improvements. Baseline BMC and BMD for total body, lumbar spine and femoral neck did not differ between MetS groups and between MetS and controls. Despite changes over time, BMC or BMD did not differ between the three modalities of exercise and when compared with the controls. However, independent of exercise modality, compliant participants increased their BMC and BMD compared with their less compliant peers. Decreases in total body lean mass and negative energy balance significantly and independently contributed to decreases in lumbar spine BMC.

Conclusion

After the one year intervention, differences relating to exercise modalities were not evident. However, compliance with an intensive exercise program resulted in a significantly higher bone mass during energy restriction than non-compliance. Exercise is therefore beneficial to bone in the context of a weight loss program.

Trial Registration

ClinicalTrials.gov NCT00917917     

Trichomes of tobacco excrete zinc as zinc-substituted calcium carbonate and other zinc-containing compounds

Tobacco (Nicotiana tabacum L. cv Xanthi) plants were exposed to toxic levels of zinc (Zn). Zn exposure resulted in toxicity signs in plants, and these damages were partly reduced by a calcium (Ca) supplement. Confocal imaging of intracellular Zn using Zinquin showed that Zn was preferentially accumulated in trichomes. Exposure to Zn and Zn + Ca increased the trichome density and induced the production of Ca/Zn mineral grains on the head cells of trichomes. These grains were aggregates of submicrometer-sized crystals and poorly crystalline material and contained Ca as major element, along with subordinate amounts of Zn, manganese, potassium, chlorine, phosphorus, silicon, and magnesium. Micro x-ray diffraction revealed that the large majority of the grains were composed essentially of metal-substituted calcite (CaCO3). CaCO3 polymorphs (aragonite and vaterite) and CaC2O4 (Ca oxalate) mono- and dihydrate also were identified, either as an admixture to calcite or in separate grains. Some grains did not diffract, although they contained Ca, suggesting the presence of amorphous form of Ca. The presence of Zn-substituted calcite was confirmed by Zn K-edge micro-extended x-ray absorption fine structure spectroscopy. Zn bound to organic compounds and Zn-containing silica and phosphate were also identified by this technique. The proportion of Zn-substituted calcite relative to the other species increased with Ca exposure. The production of Zn-containing biogenic calcite and other Zn compounds through the trichomes is a novel mechanism involved in Zn detoxification. This study illustrates the potential of laterally resolved x-ray synchrotron radiation techniques to study biomineralization and metal homeostasis processes in plants.     

Flavonoid accumulation in Arabidopsis repressed in lignin synthesis affects auxin transport and plant growth

In Arabidopsis thaliana, silencing of hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT), a lignin biosynthetic gene, results in a strong reduction of plant growth. We show that, in HCT-silenced plants, lignin synthesis repression leads to the redirection of the metabolic flux into flavonoids through chalcone synthase activity. Several flavonol glycosides and acylated anthocyanin were shown to accumulate in higher amounts in silenced plants. By contrast, sinapoylmalate levels were barely affected, suggesting that the synthesis of that phenylpropanoid compound might be HCT-independent. The growth phenotype of HCT-silenced plants was shown to be controlled by light and to depend on chalcone synthase expression. Histochemical analysis of silenced stem tissues demonstrated altered tracheary elements. The level of plant growth reduction of HCT-deficient plants was correlated with the inhibition of auxin transport. Suppression of flavonoid accumulation by chalcone synthase repression in HCT-deficient plants restored normal auxin transport and wild-type plant growth. By contrast, the lignin structure of the plants simultaneously repressed for HCT and chalcone synthase remained as severely altered as in HCT-silenced plants, with a large predominance of nonmethoxylated H units. These data demonstrate that the reduced size phenotype of HCT-silenced plants is not due to the alteration of lignin synthesis but to flavonoid accumulation.