Uncultivated Foods in Southern Veracruz,Mexico: Establishing the Links between Ecosystem Health,Food Availability,and Human Nutrition

Uncultivated foods have received little attention in the scientific literature and nutrition programs of Mexico because they are usually seen as complementary to agricultural activities, i.e., corn planting and harvesting. Using an ecosystem approach to human health, this article examines the availability, nutritional contribution, and consumption patterns by gender and age of such foods in Ixhuapan and Ocozotepec, two native communities of southern Veracruz, Mexico. The research shows important differences between both communities. Ixhuapan has a more uniform environment and its people have opted for commercial activities and land parceling. Land use changes have led to a decrease in the number of people engaged in subsistence agriculture, environmental degradation, lower corn yields, and the loss of traditional, uncultivated foods. These changes have had a negative impact on the nutritional status of Ixhuapan children and adults, particularly women. Within each community, however, there are also important differences in terms of access to resources based on gender and age. Men catch game and large fish while women catch shrimp. Men gather seasonal plants in the forest while women gather wild weeds in the cornfields and spices in their backyards. Boys, more often than girls, obtain fruits from trees located in their backyard or the town’s public spaces. The article shows that women’s food resources are frequently consumed and constitute good sources of micronutrients.     

Early Origin of Genes Encoding Subunits of Biogenesis of Lysosome‐related Organelles Complex‐1, ‐2 and ‐3

Biogenesis of lysosome‐related organelles complex (BLOC)‐1, ‐2 and ‐3 are three multi‐subunit protein complexes that are deficient in various forms of Hermansky‐Pudlak syndrome, a human disease characterized by abnormal formation of lysosome‐related organelles. Contrasting views have arisen on the evolutionary origin of these protein complexes. One view is that the BLOCs represent a recent evolutionary ‘acquisition’ unique to metazoans. However, the yeast proteins Mon1, Ccz1 and She3 have been reported to display homology to the HPS1 and HPS4 subunits of BLOC‐3 and the BLOS2 subunit of BLOC‐1, respectively. In this work, we have systematically searched for orthologs of BLOC subunits in the annotated genomes of over 160 species of eukaryotes, including metazoans and fungi in the Opisthokonta group as well as highly divergent organisms. We have found orthologs of six of the eight BLOC‐1 subunits, two of the three BLOC‐2 subunits, and the two BLOC‐3 subunits, in some non‐opisthokonts such as Dictyostelium discoideum, suggesting an early evolutionary origin for these complexes. On the other hand, we have obtained no evidence in support of the notion that yeast She3 would be an ortholog of BLOS2, and found that yeast Mon1 and Ccz1, despite displaying restricted homology to portions of HPS1 and HPS4, are unlikely to represent the orthologs of these BLOC‐3 subunits. Potential orthologs of Mon1 and Ccz1 were found in humans and several other eukaryotes.     

Oxidative stress promotes the increase of matrix metalloproteinases-2 and -9 activities in the feto-placental unit of diabetic rats

Maternal diabetes increases the risk of congenital malformations, placental dysfunction and diseases in both the neonate and the offspring's later life. Oxidative stress has been involved in the etiology of these abnormalities. Matrix metalloproteases (MMPs), involved in multiple developmental pathways, are increased in the fetus and placenta from diabetic experimental models. As oxidants could be involved in the activation of latent MMPs, we investigated a putative relationship between MMPs activities and oxidative stress in the feto-placental unit of diabetic rats at midgestation. We found that H₂O₂ enhanced and that superoxide dismutase (SOD) reduced MMPs activities in the maternal side of the placenta and in the fetuses from control and diabetic rats. MMPs were not modified by oxidative status in the fetal side of the placenta. Lipid peroxidation was enhanced in the maternal and fetal sides of the placenta and in the fetus from diabetic rats when compared to controls, and gradually decreased from the maternal placental side to the fetus in diabetic animals. The activities of the antioxidant enzymes SOD and catalase were decreased in the maternal placental side, catalase activity was enhanced in the fetal placental side and both enzymes were increased in the fetuses from diabetic rats when compared to controls. Our data demonstrate changes in the oxidative balance and capability of oxidants to upregulate MMPs activity in the feto-placental unit from diabetic rats, a basis to elucidate links between oxidative stress and alterations in the developmental pathways in which MMPs are involved.     

Modulation of glucan-enzyme interactions by domain V in GTF-SI from Streptococcus mutans

Glucansucrase GTF-SI from Streptococcus mutans is a multidomain enzyme that catalyzes the synthesis of glucan polymers. Domain V locates 100 Å from the catalytic site and is required for an optimal activity. Nevertheless, the mechanism governing its functional role remains elusive. In this work, homology modeling and molecular dynamics simulations were employed to examine the effect of domain V in the structure and glucan-binding ability of GTF-SI in full and truncated enzyme models. Our results showed that domain V increases the flexibility of the α4′-loop-α4″ motif near the catalytic site resulting in a higher surface for glucan association, and modulates the orientation of a growing oligosaccharide (N=8-23) in glucan-enzyme complexes towards engaging in favorable contacts throughout the protein, whereas in the truncated model the glucan protrudes randomly from domain B towards the solvent. These results are valuable to increase understanding about the functional role of domain V in GH70 glucansucrases.     

Population and Genetic Study of Vibrio cholerae from the Amazon Environment Confirms that the WASA-1 Prophage Is the Main Marker of the Epidemic Strain that Circulated in the Region

Vibrio cholerae is a natural inhabitant of many aquatic environments in the world. Biotypes harboring similar virulence-related gene clusters are the causative agents of epidemic cholera, but the majority of strains are harmless to humans. Since 1971, environmental surveillance for potentially pathogenic V. cholerae has resulted in the isolation of many strains from the Brazilian Amazon aquatic ecosystem. Most of these strains are from the non-O1/non-O139 serogroups (NAGs), but toxigenic O1 strains were isolated during the Latin America cholera epidemic in the region (1991-1996). A collection of environmental V. cholerae strains from the Brazilian Amazon belonging to pre-epidemic (1977-1990), epidemic (1991-1996), and post-epidemic (1996-2007) periods in the region, was analyzed. The presence of genes related to virulence within the species and the genetic relationship among the strains were studied. These variables and the information available concerning the strains were used to build a Bayesian multivariate dependency model to distinguish the importance of each variable in determining the others. Some genes related to the epidemic strains were found in environmental NAGs during and after the epidemic. Significant diversity among the virulence-related gene content was observed among O1 strains isolated from the environment during the epidemic period, but not from clinical isolates, which were analyzed as controls. Despite this diversity, these strains exhibited similar PFGE profiles. PFGE profiles were significant while separating potentially epidemic clones from indigenous strains. No significant correlation with isolation source, place or period was observed. The presence of the WASA-1 prophage significantly correlated with serogroups, PFGE profiles, and the presence of virulence-related genes. This study provides a broad characterization of the environmental V. cholerae population from the Amazon, and also highlights the importance of identifying precisely defined genetic markers such as the WASA-1 prophage for the surveillance of cholera.     

Pure and mixed plantations of Persian walnut (Juglans regia L.) for high quality timber production in Chile,South America

波斯胡桃(Juglans regia L.)是用于装饰工业的一种森林物种，需要适当的管理才能生产出经济效益好的高质量原木。由于种间关联和管理水平可以提高林分生产力，因此本研究的创新之处在于评估波斯胡桃在不同混合种植中以及在适度的管理强度的纯人工林中的表现。在两种截然不同的管理方案下种植纯林和混交林后，连续7年每年对波斯胡桃的生长、直度和存活率进行测定。在第7年时，记录所有人工林中病害情况。在每种管理强度下，除纯林外，检验三种混交林：仅与主要森林物种混交、主要森林物种和黑桤木(Alnus glutinosa L.，伴生种)混交，以及主要物种和灌木俄罗斯橄榄(Elaeagnus angustifolia L.，保育种)混交。利用重复生长数据对人工林类型与管理方案之间的交互作用进行检验。研究发现人工林类型与管理方案的交互作用显著，表明在管理水平高和低的条件下，人工林效应存在不同的机制。与纯林相比，在低管理水平下，有保育灌木混交的波斯胡桃的树高增加了78%、直径生长增加了53%。同样，在管理强度不高的情况下，与灌木混交有更多的健康益处(胡桃枯萎病的发生率低于单一栽培)和更好的直度。在高管理强度下(灌溉、施肥、抚育和频繁修剪)，与俄罗斯橄榄混交时这些有益效应消失。因此，波斯胡桃种植园的具体选址设计取决于可预见的管理强度。     

Neutral Theory Predicts the Relative Abundance and Diversity of Genetic Elements in a Broad Array of Eukaryotic Genomes

It is universally true in ecological communities, terrestrial or aquatic, temperate or tropical, that some species are very abundant, others are moderately common, and the majority are rare. Likewise, eukaryotic genomes also contain classes or “species” of genetic elements that vary greatly in abundance: DNA transposons, retrotransposons, satellite sequences, simple repeats and their less abundant functional sequences such as RNA or genes. Are the patterns of relative species abundance and diversity similar among ecological communities and genomes? Previous dynamical models of genomic diversity have focused on the selective forces shaping the abundance and diversity of transposable elements (TEs). However, ideally, models of genome dynamics should consider not only TEs, but also the diversity of all genetic classes or “species” populating eukaryotic genomes. Here, in an analysis of the diversity and abundance of genetic elements in >500 eukaryotic chromosomes, we show that the patterns are consistent with a neutral hypothesis of genome assembly in virtually all chromosomes tested. The distributions of relative abundance of genetic elements are quite precisely predicted by the dynamics of an ecological model for which the principle of functional equivalence is the main assumption. We hypothesize that at large temporal scales an overarching neutral or nearly neutral process governs the evolution of abundance and diversity of genetic elements in eukaryotic genomes.