Ornamental traits modification by Rol genes in Osteospermum ecklonis transformed with Agrobacterium tumefaciens

Summary Transgenic plants of Osteospermum ecklonis were produced by cocultivation of leaf fragments with Agrobacterium tumefaciens harboring rol genes from A. rhizogenes. The phenotypic alterations caused by the different transgenes were evaluated in field trials. The genetic manipulation produced transgenic plants characterized by the following features: 1) increased number of flowers (e.g., 35SrolC and rolABC); 2) early flowering (e.g., 35SrolC); 3) change of plant growth habit: erect (rolAB, rolABC and 35SrolC) with an increased number of branches (e.g., rolABC). The color of leaves was pale green in 35SrolC and dark green in rolAB transgenic plants. In conclusion this work reports: 1) genetic engineering of the ornamental species O. ecklonis, 2) modification of the main ornamental traits of this species by rol genes, and 3) segregation of the transgenes in the progeny.     

CiliateGEM: an open-project and a tool for predictions of ciliate metabolic variations and experimental condition design

Background

The study of cell metabolism is becoming central in several fields such as biotechnology, evolution/adaptation and human disease investigations. Here we present CiliateGEM, the first metabolic network reconstruction draft of the freshwater ciliate Tetrahymena thermophila. We also provide the tools and resources to simulate different growth conditions and to predict metabolic variations. CiliateGEM can be extended to other ciliates in order to set up a meta-model, i.e. a metabolic network reconstruction valid for all ciliates.Ciliates are complex unicellular eukaryotes of presumably monophyletic origin, with a phylogenetic position that is equal from plants and animals. These cells represent a new concept of unicellular system with a high degree of species, population biodiversity and cell complexity. Ciliates perform in a single cell all the functions of a pluricellular organism, including locomotion, feeding, digestion, and sexual processes.

Results

After generating the model, we performed an in-silico simulation with the presence and absence of glucose. The lack of this nutrient caused a 32.1% reduction rate in biomass synthesis. Despite the glucose starvation, the growth did not stop due to the use of alternative carbon sources such as amino acids.

Conclusions

The future models obtained from CiliateGEM may represent a new approach to describe the metabolism of ciliates. This tool will be a useful resource for the ciliate research community in order to extend these species as model organisms in different research fields. An improved understanding of ciliate metabolism could be relevant to elucidate the basis of biological phenomena like genotype-phenotype relationships, population genetics, and cilia-related disease mechanisms.

     

Habitat use at fine spatial scale: how does patch clustering criteria explain the use of meadows by red deer?

Large mammalian herbivores are keystone species in different ecosystems. To mediate the effects of large mammalian herbivores on ecosystems, it is crucial to understand their habitat selection pattern. At finer scales, herbivore patch selection depends strongly on plant community traits and therefore its understanding is constrained by patch definition criteria. Our aim was to assess which criteria for patch definition best explained use of meadows by wild, free-ranging, red deer (Cervus elaphus) in a study area in Northeast Portugal. We used two clustering criteria types based on floristic composition and gross forage classes, respectively. For the floristic criteria, phytosociological approach was used to classify plant communities, and its objectivity evaluated with a mathematical clustering of the floristic relevés. Cover of dominant plant species was tested as a proxy for the phytosociological method. For the gross forage classes, the graminoids/forbs ratio and the percentage cover of legumes were used. For assessing deer relative use of meadows we used faecal accumulation rates. Patches clustered according to floristic classification better explained selection of patches by deer. Plant community classifications based on phytosociology, or proxies of this, used for characterizing meadow patches resulted useful to understand herbivore selection pattern at fine scales and thus potentially suitable to assist wildlife management decisions.     

Hepcidin assay in serum by SELDI-TOF-MS and other approaches

Hepcidin, a liver peptide hormone, is the central regulator of iron homeostasis. Hepcidin synthesis is modulated by iron stores, so that iron repletion increases its levels to prevent pathological overload, while iron deficiency strongly inhibits hepcidin to allow an increase in iron absorption from duodenal cells. The emerging pivotal role of hepcidin in iron homeostasis, along with its important links with basic pathways like inflammation, makes the availability of an accurate hepcidin assay as a potentially powerful investigative tool to improve our understanding as well as our diagnostic/prognostic capabilities in many human diseases. There has been a great interest worldwide in developing a reliable and widely applicable assay of the hormone in biological fluids. Being optimal for low-molecular-weight biomarkers, SELDI-TOF-MS has emerged as a valid tool for hepcidin assay. Here we review recent results obtained with this technique, as well as with other Mass Spectrometry-based and immunological methods.     

Solution structure of the bacterial frataxin ortholog, CyaY: mapping the iron binding sites

CyaY is the bacterial ortholog of frataxin, a small mitochondrial iron binding protein thought to be involved in iron sulphur cluster formation. Loss of frataxin function leads to the neurodegenerative disorder Friedreich's ataxia. We have solved the solution structure of CyaY and used the structural information to map iron binding onto the protein surface. Comparison of the behavior of wild-type CyaY with that of a mutant indicates that specific binding with a defined stoichiometry does not require aggregation and that the main binding site, which hosts both Fe(2+) and Fe(3+), occupies a highly anionic surface of the molecule. This function is conserved across species since the corresponding region of human frataxin is also able to bind iron, albeit with weaker affinity. The presence of secondary binding sites on CyaY, but not on frataxin, hints at a possible polymerization mechanism. We suggest mutations that may provide further insights into the frataxin function.     

Presence of telomeric and subtelomeric sequences at the fusion points of ring chromosomes indicates that the ring syndrome is caused by ring instability

In situ hybridization of a telomeric (TTA-GGG) _n sequence to metaphases from three cases of ring chromosome, involving respectively chromosomes 4, 16, and 20, showed the presence of the cognate sequences in all three rings. To investigate whether these ring chromosomes originated by telomere-telomere fusion, we determined, by in situ hybridization, whether telomere-associated sequences and/or specific distal sequences were still present in the ring chromosomes. The finding that these sequences were preserved in all the ring chromosomes strongly indicates that they originated by telomere-telomere fusion. All three subjects carrying the ring chromosomes are affected by the so-called ring syndrome, with failure to thrive, minor dysmorphic signs and no major anomalies. The r(4) patient has the ring in mosaic form with a normal cell line and has normal intelligence. The r(16) and the r(20) patients have moderate mental retardation and suffer from seizures. We conclude that the ring syndrome, even in its more severe manifestation, is caused by ring chromosome instability.     

Peptides and the development of double- and triple-resonance solid-state NMR of aligned samples.

Peptides have been instrumental in the development of solid-state nuclear magnetic resonance (NMR) spectroscopy, and their roles in the development of solid-state NMR of aligned samples is reviewed. In particular, the roles of synthetic peptides in the development of triple-resonance methods are described. Recent developments of pulse sequences and NMR probes for triple-resonance NMR of aligned samples are presented.     

Antifungal metabolites (monorden, monocillins I, II, III) from Colletotrichum graminicola, a systemic vascular pathogen of maize

Colletotrichum graminicola is a systemic vascular pathogen that causes anthracnose stalk rot and leaf blight of maize. In the course of an effort to explore the potential presence and roles of C. graminicola metabolites in maize, ethyl acetate extracts of solid substrate fermentations of several C. graminicola isolates from Michigan and Illinois were found to be active against Aspergillus flavus and Fusarium verticillioides, both mycotoxin-producing seed-infecting fungal pathogens. Chemical investigations of the extract of one such isolate (NRRL 47511) led to the isolation of known metabolites monorden (also known as radicicol) and monocillins I–III as major components. Monorden and monocillin I displayed in vitro activity against the stalk- and ear-rot pathogen Stenocarpella maydis while only the most abundant metabolite (monorden) showed activity against foliar pathogens Alternaria alternata, Bipolaris zeicola, and Curvularia lunata. Using LC–HRESITOFMS, monorden was detected in steam-sterilized maize stalks and stalk residues inoculated with C. graminicola but not in the necrotic stalk tissues of wound-inoculated plants grown in an environmental chamber. Monorden and monocillin I can bind and inhibit plant Hsp90, a chaperone of R-proteins. It is hypothesized that monorden and monocillins could support the C. graminicola disease cycle by disrupting maize plant defenses and by excluding other fungi from necrotic tissues and crop residues. This is the first report of natural products from C. graminicola, as well as the production of monorden and monocillins by a pathogen of cereals.     

Fix your eyes in the space you could reach: neurons in the macaque medial parietal cortex prefer gaze positions in peripersonal space

Interacting in the peripersonal space requires coordinated arm and eye movements to visual targets in depth. In primates, the medial posterior parietal cortex (PPC) represents a crucial node in the process of visual-to-motor signal transformations. The medial PPC area V6A is a key region engaged in the control of these processes because it jointly processes visual information, eye position and arm movement related signals. However, to date, there is no evidence in the medial PPC of spatial encoding in three dimensions. Here, using single neuron recordings in behaving macaques, we studied the neural signals related to binocular eye position in a task that required the monkeys to perform saccades and fixate targets at different locations in peripersonal and extrapersonal space. A significant proportion of neurons were modulated by both gaze direction and depth, i.e., by the location of the foveated target in 3D space. The population activity of these neurons displayed a strong preference for peripersonal space in a time interval around the saccade that preceded fixation and during fixation as well. This preference for targets within reaching distance during both target capturing and fixation suggests that binocular eye position signals are implemented functionally in V6A to support its role in reaching and grasping.