Perception of geometric sequences and numerosity both predict formal geometric competence in primary school children

While most animals have a sense of number, only humans have developed symbolic systems to describe and organize mathematical knowledge. Some studies suggest that human arithmetical knowledge may be rooted in an ancient mechanism dedicated to perceiving numerosity, but it is not known if formal geometry also relies on basic, non-symbolic mechanisms. Here we show that primary-school children who spontaneously detect and predict geometrical sequences (non-symbolic geometry) perform better in school-based geometry tests indexing formal geometric knowledge. Interestingly, numerosity discrimination thresholds also predicted and explained a specific portion of variance of formal geometrical scores. The relation between these two non-symbolic systems and formal geometry was not explained by age or verbal reasoning skills. Overall, the results are in line with the hypothesis that some human-specific, symbolic systems are rooted in non-symbolic mechanisms.

Exploring tomato Solanum pennellii introgression lines for residual biomass and enzymatic digestibility traits

Background

Residual biomass production for fuel conversion represents a unique opportunity to avoid concerns about compromising food supply by using dedicated feedstock crops. Developing tomato varieties suitable for both food consumption and fuel conversion requires the establishment of new selection methods.

Results

A tomato Solanum pennellii introgression population was assessed for fruit yield, biomass phenotypic diversity, and for saccharification potential. Introgression lines 2–5, 2–6, 6–3, 7–2, 10–2 and 12–4 showed the best combination of fruit and residual biomass production. Lignin, cellulose, hemicellulose content and saccharification rate showed a wide variation in the tested lines. Within hemicellulose, xylose value was high in IL 6–3, IL 7–2 and IL 6–2, whereas arabinose showed a low content in IL 10–2, IL 6–3 and IL 2–6. The latter line showed also the highest ethanol potential production. Alkali pre-treatment resulted in the highest values of saccharification in most of lines tested, suggesting that chemical pretreatment is an important factor for improving biomass processability. Interestingly, extreme genotypes for more than one single trait were found, allowing the identification of better genotypes. Cell wall related genes mapping in genomic regions involved into tomato biomass production and digestibility variation highlighted potential candidate genes. Molecular expression profile of few of them provided useful information about challenged pathways.

Conclusions

The screening of S. pennellii introgression population resulted very useful for delving into complex traits such as biomass production and digestibility. The extreme genotypes identified could be fruitfully employed for both genetic studies and breeding.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-016-0362-9) contains supplementary material, which is available to authorized users.

A New Flow Cytometry Technique to Identify Phaeomoniella chlamydospora Exopolysaccharides and Study Mechanisms of Esca Grapevine Foliar Symptoms

A flow cytometry technique that unequivocally identifies some of the toxic metabolites produced by Phaeomoniella chlamydospora, one of the main fungal pathogens causing esca disease of grapevine (Vitis vinifera), was developed. Antibodies raised against exopolysaccharides (EPS)-metabolites produced by Pa. chlamydospora that have been reported to be phytotoxic-were used as antigen to immunize rats. The specificity of these antibodies was assayed by flow cytometry against Pa. chlamydospora polysaccharides and against EPS with a different structure isolated from other phytopathogenic fungi, including Phaeoacremonium aleophilum and the Botryosphaeriaceae species Neofusicoccum luteum and N. parvum. Using this method, Pa. chlamydospora polysaccharides were detected in the symptomatic leaves of esca-affected grapevines, while healthy and asymptomatic leaves from both healthy and diseased vines did not produce a binding reaction. This method potentially could be used to develop a simple kit to study the mechanisms underlying the development of esca foliar symptoms and to indirectly assess the presence of Pa. chlamydospora in grapevine material.

Determination of Ascochyta caulina phytotoxins by high-performance anion exchange chromatography and pulsed amperometric detection

A simple and sensitive method has been developed for the rapid qualitative and quantitative analysis of the phytotoxins produced by Ascochyta caulina, a potential mycoherbicide for the biocontrol of Chenopodium album. Considering that the two main toxins produced by this fungus, namely ascaulitoxin and trans-4-amino-D-proline, and the third toxin, identified as 2,4,7-triamino-5-hydroxyoctandioic acid, have an amino acid nature, high-performance anion exchange chromatography with pulsed amperometric detection was the best method for their detection. The method was used to measure the toxin content in the culture filtrates of different strains of A. caulina. The developed method could be employed as a tool to select more virulent strains by determining the higher toxin producers, if in vitro toxin accumulation was related to pathogen virulence. The chemical characterisation of the third toxin purified from A. caulina culture filtrates is also reported.

Fungitoxic activity of some cytochalasins and their derivatives on Phytophthora species

The activity of cytochalasin B was tested on 8 Phytophthora species, while the same toxin, some of its derivatives and natural analogues, namely cytochalasin F and deoxaphomin, were assayed at 2 x 10(-5) - 2 x 10(-4) M on the most sensitive species, P. cactorum. A significant inhibitory activity on P. cactorum was shown by cytochalasin B, its 7-monoacetyl derivative, and deoxaphomin. The hydroxy group at C-20 and the conformational freedom of the macrocyclic ring proved to be important structural features for this activity. The 7-hydroxy group at C-7 appeared to have no influence on this toxicity, while a size reduction associated with the carbocyclic nature of the macrocycle seems to lightly increase the activity. The 7-O-acetylcytochalasin B showed selective toxic activity on P. cactorum at the tested concentration, thus suggesting a possible use as a fungicide for this compound.

Trans-4-aminoproline, a phytotoxic metabolite with herbicidal activity produced by Ascochyta caulina

A phytotoxic metabolite, characterized through NMR techniques and synthetic methods as trans-4-aminoproline, was isolated from the culture filtrates of Ascochyta caulina, a promising mycoherbicide for biological control of Chenopodium album. The metabolite, which shows interesting phytotoxic properties, together with ascaulitoxin (recently characterized as N.2-beta-D-glucoside of the unusual bis-amino acid 2,4,7-triamino-5-hydroxyoctandioc acid) and another unidentified compound, compose an active fraction of A. caulina culture filtrates with promising herbicidal properties. When assayed on leaves of host and non host dicots, including wild and cultivated plants, the trans-4-aminoproline showed a wide range of toxicity, with leaves of C. album being the most sensitive. Other interesting aspects were its inefficacy on several monocots, both cultivated and wild, and its lack of antifungal, antibiotic and zootoxic activities. This is the first report on trans-4-aminoproline as naturally occurring compound and phytotoxic metabolite produced by A. caulina.

[The rationalization of the follow-up of hormonal replacement treatment in menopause]

BACKGROUND

Decision making about the opportunity of starting or continuing hormone replacement therapy (HRT) in menopause should rely on an overall evaluation of its risks and benefits for the women's health; the evaluation of HRT cost-benefit ratio, however, should include its possible outcomes from an economical point of view. In this view, and with the certainty that menopausal patients should be protected by proper treatments, our case series has been evaluated in order to improve the quality of our clinical schedules for both their access to HRT and the treatment follow-up.

METHODS

Two groups of patients have been considered the first one consisted of 560 women observed during '97 for climacteric symptoms and candicated to begin HRT. The second one consisted of 100 women on HRT for 1 to 6 years. In the first group we considered which test and with which frequency were responsible for stopping or delay the beginning of therapy; while in the second group we evaluated the reasons for stopping treatment.

RESULTS AND CONCLUSIONS

On the basis of our experience, the exams required before starting HRT seem to be the following: patient history, mammography, densitometry and endometrial sample as well as the parameters of glucose lipidic, coagulative and hepatic metabolism. Densitometry is useful in the annual follow-up only in patients with bone alterations from the beginning. The same exams seem required for the follow-up, with the exception of bone densitometry which should be performed yearly only in patients with bone demineralization.

Structure-activity relationship studies of putaminoxins and pinolidoxins: phytotoxic nonenolides produced by phytopathogenic Phoma and Ascochyta species

Putaminoxin and pinolidoxin, two structurally related nonenolides, isolated respectively from organic extracts of Phoma putaminum and Aschochyta pinodes cultures, together with some of their natural analogs and synthetic derivatives, were used in a structure-activity relationship study. Their phytotoxic, antifungal and zootoxic activities were assayed with the aim to find compounds with potential herbicidal properties. The strongest phytotoxic compounds proved to be putaminoxin and pinolidoxin, whose activity appeared to be correlated to the integrity of the nonenolide ring and to the presence of both the hydroxy groups and the unmodified propyl side chain. None of the assayed nonenolides showed antifungal activity, whereas pinolidoxin analogs and derivatives showed high to weak zootoxicity.

Identification by flow cytometry of seiridin, one of the main phytotoxins produced by three Seiridium species pathogenic to cypress

Seiridin (SE), one of the main phytotoxins produced in vitro by Seiridium species pathogenic to cypress, was oxidized and the corresponding ketone derivative covalently linked to bovine serum albumin (BSA). The conjugate (SE-BSA) was used to prepare an antiserum to SE. The antibodies were absorbed with BSA and their specificity was assayed by ELISA and flow cytometry against SE, iso-seiridin (ISE), a structural isomer of SE, and some derivatives of these two metabolites. The antibodies tested in a competitive indirect ELISA did not show any binding activity to SE, ISE and their derivatives. The cytometry test, instead, was successful. SE-BSA and SE showed the highest binding activity with the antibodies. SE derivatives having a shift on the adjacent carbon, oxidation, or acetylation of the hydroxy group of the heptyl side chain at C-4 or conversion of the gamma-lactone in the corresponding planar furane ring reacted less than SE. The 2'-dansylhydrazoneSE and the 3,4-dihydroSE having a bulky group attached to the heptyl side chain and a saturated lactone ring, respectively, showed a weak reactivity. SE derivatives in which the gamma-lactone ring was destroyed and ISE derivatives presenting the shift of the hydroxy group at C-3' and another structural modification had no binding activity.

Toxic metabolites from phytopathogenic Ascochyta species

We review some chemical and biological aspects of toxic metabolites produced in vitro by phytopathogenic Ascochyta species, fungi having agrarian and toxicological importance. In particular, here the isolation of some known and new cytochalasins from A. heteromorpha and A. lathyri, four new nonenolides from A. pinodes and a new trisubstituted derivative of salycilic aldehyde from A. pisi are described. Furthermore, the identification of medicarpin, phytoalexin found in the chickpea seeds naturally infected by A. rabiei is also reported.