Dammarane triterpenes from Cabralea canjerana (Vell.) Mart. (Meliaceae): Their chemosystematic significance

The stem of Cabralea canjerana (Vell.) Mart. yielded three new dammarane triterpenes 20S,24S-epoxy-7β,25-dihydroxy-3,4-secodammar-4(28)-en-3-oic acid, 20S,24S-epoxy-7β,15α,25-trihydroxy-3,4-secodammar-4(28)-en-3-oic acid and 20S,24R-epoxy-7β,22ξ,25-trihydroxy-3,4-secodammar-4(28)-en-3-oic acid, which were identified on the basis of spectroscopic methods. The known dammarane triterpenes ocotillone, eichlerianic acid, shoreic acid and the sterols sitosterol, campesterol, stigmasterol, sitostenone and stigmast-5-en-3-one were also isolated and identified. The branches yielded the above three known dammaranes and eichlerialactone. The dammaranes in C. canjerana display strong similarities with Trichilieae tribe, which contains several dammaranes. The data reported herein thus provide firm support for placing Cabralea within the subfamily Melioideae, Trichilieae tribe.     

Mycotoxins in Mexico: Epidemiology, management, and control strategies

Mycotoxin-producing molds species are extremely common. Many of them provoke serious diseases in humans and animals. These toxins occur, with varying severity, in agricultural products. Since Mexico is a big crops producer, the importance of the presence of these toxins is high. Currently, the Mexican regulation establishes limits only for aflatoxins in cereals and cereal products. No limits are set for other mycotoxins. Epidemiological data although limited, has shown that an important number of samples contain mycotoxin limits above those established abroad. Several strategies for reducing contamination have been conducted in the country such as development of hybrid corn, control of insect population, use of natural products, and modification of nixtamalization and extraction procedures. Although significant research on this field has been conducted, there is still a great need for information to determine the incidence of mycotoxins in Mexican products.     

DFNB68, a novel autosomal recessive non-syndromic hearing impairment locus at chromosomal region 19p13.2

From a large collection of families with autosomal recessive non-syndromic hearing impairment (NSHI) from Pakistan, linkage has been established for two unrelated consanguineous families to 19p13.2. This new locus was assigned the name DFNB68. A 10 cM genome scan and additional fine mapping were carried out using microsatellite marker loci. Linkage was established for both families to DFNB68 with maximum multipoint LOD scores of 4.8 and 4.6. The overlap of the homozygous regions between the two families was bounded by D19S586 and D19S584, which limits the locus interval to 1.9 cM and contains 1.4 Mb. The genes CTL2, KEAP1 and CDKN2D were screened but were negative for functional sequence variants.Regie Lyn P. Santos and Muhammad Jawad Hassan contributed equally to this work.     

A novel autosomal recessive non-syndromic hearing impairment locus (DFNB47) maps to chromosome 2p25.1-p24.3

Hereditary hearing impairment (HI) displays extensive genetic heterogeneity. Autosomal recessive (AR) forms of prelingual HI account for ~75% of cases with a genetic etiology. A novel AR non-syndromic HI locus (DFNB47) was mapped to chromosome 2p25.1-p24.3, in two distantly related Pakistani kindreds. Genome scan and fine mapping were carried out using microsatellite markers. Multipoint linkage analysis resulted in a maximum LOD score of 4.7 at markers D2S1400 and D2S262. The three-unit support interval was bounded by D2S330 and D2S131. The region of homozygosity was found within the three-unit support interval and flanked by markers D2S2952 and D2S131, which corresponds to 13.2 cM according to the Rutgers combined linkage-physical map. This region contains 5.3 Mb according to the sequence-based physical map. Three candidate genes, KCNF1, ID2 and ATP6V1C2 were sequenced, and were found to be negative for functional sequence variants.     

Gp63-Like Molecules in <Emphasis Type="Italic">Phytomonas serpens</Emphasis>: Possible Role in the Insect Interaction

In this study, we demonstrated that metallopeptidase inhibitors (EDTA, EGTA, and 1,10-phenanthroline) were able to arrest Phytomonas serpens growth in distinct patterns. This parasite released exclusively metallopeptidases to the extracellular environment, whereas in cellular extracts only cysteine peptidases were detected. In addition, an extracellular polypeptide of 60 kDa reacted in Western blotting probed with polyclonal antibody raised against gp63 of Leishmania amazonensis. In the cellular parasite extract, this antibody recognized bands migrating at 63 and 52 kDa, which partitioned on both aqueous and membrane-rich fractions. Flow cytometry and fluorescence microscopy analyses showed that the gp63-like molecules have a surface location. Moreover, phospholipase C (PLC)-treated parasites reduced the number of gp63-positive cells. The anti-cross-reacting determinant (CRD) and anti-gp63 antibodies recognized the 60-kDa band in the supernatant from PLC-treated cells, suggesting that this protein is glycosylphosphatidylinositol-anchored to the plasma membrane. This is the first report on the presence of gp63-like molecules in members of the Phytomonas genus. The pretreatment of the parasites with anti-gp63 antibody significantly diminished their adhesion index to explanted salivary glands of the phytophagous insect Oncopeltus fasciatus, suggesting a potential involvement of the gp63-like molecules in the adhesive process of this plant trypanosomatid.     

Environmental factors influence on chemical polymorphism of the essential oils of Lychnophora ericoides

Lychnophora ericoides is a Brazilian medicinal plant used in folk medicine as an anti-inflammatory and analgesic agent. The essential oils from leaves of two populations with and without scent, collected at 2-month intervals during an 1-year period, were analysed by GC-MS. The results were submitted to principal component and cluster analysis which allowed two groups of essential oils to be distinguished with respect to sampling site and scent: cluster I (Vianópolis site, with specimens exhibiting an aromatic scent) containing a high percentage of alpha-bisabolol (44.7-76.4%) and alpha-cadinol (10.9-23.5%), and cluster II (Cristalina site, with specimens without scent) characterised by a high content of (E)-nerolidol (31.3-47.1%) and ar-dihydro-turmerone (4.8-15.4%). The canonical discriminant analysis showed that using the data set of the seven sampling months and (E)-nerolidol and alpha-bisabolol as predictable variables, it was possible to distinguish between the samples harvested according to Cerrado seasons, dry winter (May-September) and humid summer (November-March). In addition, canonical correlation analysis between the soil sampling sites and the populations revealed a significant relationship between oil components and edaphic factors. Oxygenated sesquiterpenes and potential acidity, Al saturation, cationic exchange capacity, silt, and sand load as the first canonical variate were fairly strongly related to samples collected in Vianópolis site. On the other hand, monoterpenes and sesquiterpene hydrocarbons were strongly related to chemical balance in soils (organic matter, P and base saturation), which is related to samples at the Cristalina site. The chemovariation observed appears to be environmentally determined.     

Cadinane sesquiterpenoids of Phomopsis cassiae, an endophytic fungus associated with Cassia spectabilis (Leguminosae)

Five cadinane sesquiterpenes derivatives were isolated by bioassay-guided fractionation from Phomopis cassiae, an endophytic fungus isolated from Cassia spectabilis. The structures of the two diastereoisomeric 3,9,12-trihydroxycalamenenes (1, 2); 3,12-dihydroxycalamenene (3); 3,12-dihydroxycadalene (4) and 3,11,12-trihydroxycadalene (5) were established on the basis of analyses of 1D and 2D NMR and HRTOFMS experiments. Antifungal activity of the isolates was evaluated against Cladosporium sphaerospermum and Cladosporium cladosporioides, revealing 5 as the most active compound.     

Annual changes in the concentration of minerals and organic compounds of Quercus suber leaves

Mature leaves are the primary source of sugars, which give rise to many secondary metabolites required for plant survival under adverse conditions. In order to study the interaction of field‐grown cork oak (Quercus suber L.) with the environment, we investigated the seasonal variation of minerals and organic metabolites in the leaves, using inductively coupled plasma atomic emission spectrometry, elemental analysis and nuclear magnetic resonance spectrometry. Statistical analysis showed that the data strongly correlated with seasonal climate and were divided in three groups corresponding to: (1) spring‐early summer, (2) summer and (3) autumn‐winter. The concentration of N, P, K and leaf ash content were highest in spring (recently formed leaves), reached the minimum during the hot and dry summer and increased slightly during the rainy period of autumn‐winter. Conversely, Na, Mg and Ca concentrations were lowest in spring‐early summer and increased during summer and autumn‐winter, the Ca concentration increasing five‐fold. Two cyclitol derivatives, quinic acid and quercitol were the major organic metabolites of the leaves. Their concentration along the season followed opposite trends. While quinic acid predominated during spring‐early summer, when it contributed 12% to the leaf osmotic potential, quercitol was predominant during autumn‐winter, when its contribution to leaf osmotic potential was about 10%. This different preponderance of the two compounds is expressed by the quercitol/quinic acid ratio, which can be as low as 0.2 in early summer and as high as 9 in winter. Sucrose and glucose concentrations also increased during autumn‐winter. Evidence for the quercitol protective role in plants during stress is discussed, and on the basis of structural similarity, it is suggested that quinic acid could have an identical importance, with a protective role against heat and high irradiance. It is concluded that the marked changes in Q. suber leaf composition throughout the year could have important implications in the plant capacity to endure climatic stress.     

Frequency of serovars and antimicrobial resistance in Shigella spp. from Brazil

A total of 296 Shigella spp. were received from State Public Health Laboratories, during the period from 1999 to 2004, by National Reference Laboratory for Cholera and Enteric Diseases (NRLCED)--IOC/Fiocruz, Rio de Janeiro, Brazil. The frequency of Shigella spp. was: S. flexneri (52.7%), S. sonnei (44.2%), S. boydii (2.3%), and S. dysenteriae (0.6%). The most frequent S. flexneri serovars were 2a and 1b. The highest incidence rates of Shigella isolation were observed in the Southeast (39%) and Northeast (34%) regions and the lowest rate in the South (3%) of Brazil. Strains were further analyzed for antimicrobial susceptibility by disk diffusion method as part of a surveillance program on antimicrobial resistance. The highest rates of antimicrobial resistance were to trimethoprim-sulfamethozaxole (90%), tetracycline (88%), ampicillin (56%), and chloramphenicol (35%). The patterns of antimicrobial resistance among Shigella isolates pose a major difficulty in the determination of an appropriate drug for shigellosis treatment. Continuous monitoring of antimicrobial susceptibilities of Shigella spp. through a surveillance system is thus essential for effective therapy and control measures against shigellosis.