High pressures studies on bis(L-alaninate)copper(II) by Raman spectroscopy and synchrotron X-ray diffraction

The crystal of bis(L-alaninate)copper(II) [Cu(C3H6NO2)2] was studied by Raman spectroscopy and synchrotron X-ray diffraction as a function of hydrostatic pressure, and its vibrational and structural behavior were investigated to analyze its stability at high pressures. The Raman spectra of bis(L-alaninate)copper(II) show changes in vibrational modes that are associated with deformations and stretching of units involving the copper atom. These results indicate that molecular fragments involving the copper atom undergo rotations and discontinuities in bond lengths. The lattice parameters of bis(L-alaninate)copper(II) obtained from Le Bail fits also exhibit changes in the same pressure ranges as the Raman spectra. The discontinuities in the angular parameter beta are compatible with the rotations of the molecular fragments. Bis(L-alaninate)copper(II) undergoes changes, but maintains monoclinic symmetry in the range of 0-20.1 GPa.

Synchrotron radiation X-ray diffraction and Raman spectroscopy study of l-asparagine monohydrate doped with Fe(III) at high pressure

Crystals of l-asparagine monohydrate doped with Fe(III) were studied by Raman spectroscopy in a diamond anvil cell (DAC) in the spectral range from 100 to 3200 cm^-1 and pressures up to 9.2 GPa. The behavior of external modes suggests conformational changes between 3.0 and 4.0 GPa mainly affecting the CH₂ group. X-ray diffraction measurements with synchrotron radiation were performed in the angular range from 3 to 12 degrees (2θ) up to 9.3 GPa. The lattice parameters contract up to 9.3 GPa, with the exception of parameter b, which exhibits expansion from 7.2 GPa. The lattice parameters exhibit discontinuities between 3.0 and 4.0 GPa, this effect is compatible with conformational changes. Such modifications occur without a change in symmetry, at least up to 9.3 GPa. Under decompression, down to atmospheric pressure, the original Raman spectrum is recovered, showing that the conformational change and the other changes are all reversible.

ZnWO4 nanocrystals: synthesis, morphology, photoluminescence and photocatalytic properties

The best photocatalytic properties for monoclinic ZnWO₄ nanocrystals are related to the surface energy and the types of clusters formed on their surface.

Nutritional quality of packaged foods targeted at children in Brazil: which ones should be eligible to bear nutrient claims?

OBJECTIVES

This study aimed to assess the nutritional quality of food products marketed at children, with and without nutrient claims, using two different approaches.

METHODS

Analyses were performed based on a data set with food composition and labelling data from every packaged food marketed at children sold in a major Brazilian supermarket (n=535). Foods were classified as 'healthier' and 'less healthy' according to the UK/Ofcom nutrient profile model and to the NOVA classification based on the level of food processing. Pearson's χ² test was used to compare proportions between models. Agreement was assessed using Cohen's κ-statistic (P<0.05).

RESULTS

The NOVA model was stricter than the UK/Ofcom model, classifying more products as 'less healthy' (91.4%) compared with the nutrient profile-based model (75.0%; P<0.001). Agreement between models was 79.4% (k=0.30), because 72.9% (n=390) of products were categorised as 'less healthy' by both models, and 6.5% (n=35) as 'healthier'. Half of the food products marketed at children from the database (270; 50.5%) bore nutrient claims. From these products with nutrient claims, 95.9% (92.8-98.0) were classified as 'less healthy' by the NOVA model, whereas this percentage was 74.1% (68.4-79.2) according to the UK/Ofcom model (P<0.05).

CONCLUSIONS

The high number of foods with low nutritional quality being marketed at children via product packaging and nutrient claims should be of concern to policy makers wanting to improve children's diets and to tackle childhood obesity. The implementation of nutritional quality criteria to ensure that foods targeted at children should be eligible to bear nutrient claims on their labels could avoid a situation where claims mask the overall nutritional status of a food.

Functional and ultrastructural neuroanatomy of interactive intratectal/tectonigral mesencephalic opioid inhibitory links and nigrotectal GABAergic pathways: Involvement of GABAA and μ1-opioid receptors in the modulation of panic-like reactions elicited by electrical stimulation of the dorsal midbrain

In the present study, the functional neuroanatomy of nigrotectal-tectonigral pathways as well as the effects of central administration of opioid antagonists on aversive stimuli-induced responses elicited by electrical stimulation of the midbrain tectum were determined. Central microinjections of naloxonazine, a selective mu(1)-opiod receptor antagonist, in the mesencephalic tectum (MT) caused a significant increase in the escape thresholds elicited by local electrical stimulation. Furthermore, either naltrexone or naloxonazine microinjected in the substantia nigra, pars reticulata (SNpr), caused a significant increase in the defensive thresholds elicited by electrical stimulation of the continuum comprised by dorsolateral aspects of the periaqueductal gray matter (dlPAG) and deep layers of the superior colliculus (dlSC), as compared with controls. These findings suggest an opioid modulation of GABAergic inhibitory inputs controlling the defensive behavior elicited by MT stimulation, in cranial aspects. In fact, iontophoretic microinjections of the neurotracer biodextran into the SNpr, a mesencephalic structure rich in GABA-containing neurons, show outputs to neural substrate of the dlSC/dlPAG involved with the generation and organization of fear- and panic-like reactions. Neurochemical lesion of the nigrotectal pathways increased the sensitivity of the MT to electrical (at alertness, freezing and escape thresholds) and chemical (blockade of GABA(A) receptors) stimulation, suggesting a tonic modulatory effect of the nigrotectal GABAergic outputs on the neural networks of the MT involved with the organization of the defensive behavior and panic-like reactions. Labeled neurons of the midbrain tectum send inputs with varicosities to ipsi and contralateral dlSC/dlPAG and ipsilateral substantia nigra, pars reticulata and compacta, in which the anterograde and retrograde tracing from a single injection indicates that the substantia nigra has reciprocal connections with the dlSC/dlPAG featuring close axo-somatic and axo-dendritic appositions in both locations. In addition, ultrastructural approaches show inhibitory axo-axonic synapses in MT and inhibitory axo-somatic/axo-axonic synapses in the SNpr. These findings, in addition to the psychopharmacological evidence for the interaction between opioid and GABAergic mechanisms in the cranial aspects of the MT as well as in the mesencephalic tegmentum, offer a neuroanatomical basis of a pre-synaptic opioid inhibition of GABAergic nigrotectal neurons modulating fear in defensive behavior-related structures of the cranial mesencephalon, in a short link, and through a major neural circuit, also in GABA-containing perikarya and axons of nigrotectal neurons.

Comparative genomics of two Leptospira interrogans serovars reveals novel insights into physiology and pathogenesis

Leptospira species colonize a significant proportion of rodent populations worldwide and produce life-threatening infections in accidental hosts, including humans. Complete genome sequencing of Leptospira interrogans serovar Copenhageni and comparative analysis with the available Leptospira interrogans serovar Lai genome reveal that despite overall genetic similarity there are significant structural differences, including a large chromosomal inversion and extensive variation in the number and distribution of insertion sequence elements. Genome sequence analysis elucidates many of the novel aspects of leptospiral physiology relating to energy metabolism, oxygen tolerance, two-component signal transduction systems, and mechanisms of pathogenesis. A broad array of transcriptional regulation proteins and two new families of afimbrial adhesins which contribute to host tissue colonization in the early steps of infection were identified. Differences in genes involved in the biosynthesis of lipopolysaccharide O side chains between the Copenhageni and Lai serovars were identified, offering an important starting point for the elucidation of the organism's complex polysaccharide surface antigens. Differences in adhesins and in lipopolysaccharide might be associated with the adaptation of serovars Copenhageni and Lai to different animal hosts. Hundreds of genes encoding surface-exposed lipoproteins and transmembrane outer membrane proteins were identified as candidates for development of vaccines for the prevention of leptospirosis.

Comparative analyses of the complete genome sequences of Pierce's disease and citrus variegated chlorosis strains of Xylella fastidiosa

Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X. fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X. fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X. fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis, permitting convergence of functional genomic strategies.

The genome sequence of the plant pathogen Xylella fastidiosa. The Xylella fastidiosa Consortium of the Organization for Nucleotide Sequencing and Analysis

Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and two plasmids of 51,158 bp and 1,285 bp. We can assign putative functions to 47% of the 2,904 predicted coding regions. Efficient metabolic functions are predicted, with sugars as the principal energy and carbon source, supporting existence in the nutrient-poor xylem sap. The mechanisms associated with pathogenicity and virulence involve toxins, antibiotics and ion sequestration systems, as well as bacterium-bacterium and bacterium-host interactions mediated by a range of proteins. Orthologues of some of these proteins have only been identified in animal and human pathogens; their presence in X. fastidiosa indicates that the molecular basis for bacterial pathogenicity is both conserved and independent of host. At least 83 genes are bacteriophage-derived and include virulence-associated genes from other bacteria, providing direct evidence of phage-mediated horizontal gene transfer.

[Seroepidemiology of toxoplasmosis and ocular evaluation by Amsler grid in patients from the rural area treated at the Jaguapitã county health center, Paraná State, Brazil]

In this study, we collected serum from 82 randomly selected patients from a rural area in Jaguapitã county, Paraná State. All sera were subjected to indirect immunofluorescence assay (IFA) to detect IgG antibodies against T. gondii. Serum titers >/=+ 16 were considered positive. Of the 82 evaluated sera, 68 (82.9%) were positive to toxoplasmosis and 14 (17.1%) were non-reactive. The most common titers found were 64 (23/33.8%) and 256 (16/23.5%), the highest titer being 4096 (8/11.8%). The 82 patients were also evaluated by the Amsler Grid test, with 22 (26.8%) patients presenting at least one alteration in this test. Masculinity was found to be a protection factor in the Amsler grid test (OR = 0.21 0.04 < OR < 0. 86 chi2 = 4,98 p = 0,02). There were no significant statistical differences related to the epidemiological investigation. We concluded that T. gondii has a wide distribution in the population studied.

[Seroprevalence, epidemiology and ocular evaluation of human toxoplasmosis in the rural zone Jauguapitã (Paraná) Brazil]

Toxoplasmosis is a protozoal zoonosis common among a great variety of species worldwide. The objective of this study was to assess the presence of toxoplasmosis among 345 residents in a rural area in Jagupitã municipality, Paraná state, Brazil. The frequency of titers in human serum samples was compared with the frequency of titers found in 1,420 samples obtained from various animal species with which local residents came into contact. Titers > or = 16 were considered positive. The highest titer found was 65,536 (1%), and the most frequent titer levels were 256 (29%) and 1,024 (19%). The comparisons between humans and animals revealed a positive and significant correlation between humans and felines (r = 0.78; P = 0.01) and humans and canines (r = 0.64; P = 0.05) in terms of titer distribution. Study participants were also tested with the Amsler grid. Seventy-five of the 345 people (22%) reported some type of ocular degradation. Of these 75, 58 of them (77%) were seropositive for toxoplasmosis. Forty-one of these 58 people underwent an ophthalmologic exam. Of these 41, 9 of them, who were between 34 and 78 years old, presented lesions characteristic of healed chorioretinitis, suggesting ocular toxoplasmosis. None of the 9 had ocular inflammation. Six of the 9 patients (67%) had unilateral lesions; 4 of these 6 presented a titer level of 256. The epidemiological survey showed that the probability of presenting ocular problems was 2.06 times as great for reactive patients as for nonreactive ones. No significant differences were observed in terms of sex, contact with felines or other animals, consumption of raw or rare meat and raw milk, and slaughtering of animals for personal consumption. Our results suggest that toxoplasmosis is common in the region, with a significant incidence of ocular lesions caused by Toxoplasma gondii. Health authorities should increase their monitoring and control activities in order to decrease the risk of toxoplasmic infections, especially among pregnant women.

Dual role for the yeast THI4 gene in thiamine biosynthesis and DNA damage tolerance

The THI4 gene of Saccharomyces cerevisiae encodes an enzyme of the thiamine biosynthetic pathway. The plant homolog thi1, from Arabidopsis thaliana, is also involved in thiamine biosynthesis; but was originally cloned due to its capacity to complement DNA repair deficient phenotypes in Escherichia coli. Here, the behavior of a thi4 disrupted strain was examined for increased sensitivity to treatment with the DNA damaging agents ultraviolet radiation (UV, 254 nm) and methyl methanesulfonate (MMS). Although the thi4 null mutant showed a similar level of survival as the wild-type strain, a higher frequency of respiratory mutants was induced by the two treatments. A similar phenotype was seen with wild-type strains expressing an antisense THI4 construct. Further analysis of respiratory mutants revealed that these were due to mutations of mitochondrial DNA (mtDNA) rather than nuclear DNA, consisting of rho-petite mutants. Moreover, the frequency of mutations was unaffected by the presence or absence of thiamine in the growth medium, and the defect leading to induction of petites in the thi4 mutant was corrected by expression of the Arabidopsis thi1 gene. Thus, Thi4 and its plant homolog appear to be dual functional proteins with roles in thiamine biosynthesis and mitochondrial DNA damage tolerance.

Singlet oxygen induced mutation spectrum in mammalian cells

In order to characterize the molecular nature of singlet oxygen (1O2) induced mutations in mammalian cells, a SV40-based shuttle vector (pi SVPC13) was treated with singlet oxygen arising from the thermal decomposition of the water-soluble endoperoxide of 3,3'-(1,4-naphthylidene) dipropionate (NDPO2). After the passage of damaged plasmid through monkey COS7 cells, the vector was shuffled into E. coli cells, allowing the screening of supF mutants. The mutation spectrum analysis shows that single and multiple base substitutions arose in 82.5% of the mutants, the others being rearrangements. The distribution of mutations within the supF gene is not random and some hotspots are evident. Most of the point mutations (98.4%) involve G:C base pairs and G:C to T:A transversion was the most frequent mutation (50.8%), followed by G:C to C:G transversion (32.8%). These results indicate that mutagenesis in mammalian cells, mediated by 1O2-induced DNA damage, is targeted selectively at guanine residues.

[Evaluation of the Course II of Public Health of the Health Secretariat of Federal District: a case study]

In Brazil, Public Health specialization courses with the characteristics presently adopted by the National School of Public Health, i.e., short duration and great amplitude, are relatively recent, having started approximately fifteen years ago. In Brasília, nine such courses have been already completed, having, six of them, directive and/or teaching involvement by the authors. Results on a final assessment of one the courses are herewith presented in order to introduce our experience as a contribution to future analogous initiatives. The assessment was applied to a random sample of students, teachers and coordinators, with the objective of identifying positive and negative appreciations about methodological, operational, administrative and institutional aspects. Answers were quite variable, with the highest frequencies scored to field work and to the apprehension on admitting graduates to the Health System. Such aspects deserve final differentiated discussion.