Anthropogenic Landscape in Southeastern Amazonia: Contemporary Impacts of Low-Intensity Harvesting and Dispersal of Brazil Nuts by the Kayapó Indigenous People

Brazil nut, the Bertholletia excelsa seed, is one of the most important non-timber forest products in the Amazon Forest and the livelihoods of thousands of traditional Amazonian families depend on its commercialization. B. excelsa has been frequently cited as an indicator of anthropogenic forests and there is strong evidence that past human management has significantly contributed to its present distribution across the Amazon, suggesting that low levels of harvesting may play a positive role in B. excelsa recruitment. Here, we evaluate the effects of Brazil nut harvesting by the Kayapó Indigenous people of southeastern Amazonia on seedling recruitment in 20 B. excelsa groves subjected to different harvesting intensities, and investigated if management by harvesters influences patterns of B. excelsa distribution. The number of years of low-intensity Brazil nut harvesting by the Kayapó over the past two decades was positively related to B. excelsa seedling density in groves. One of the mechanisms behind the higher seedling density in harvested sites seems to be seed dispersal by harvesters along trails. The Kayapó also intentionally plant B. excelsa seeds and seedlings across their territories. Our results show not only that low-intensity Brazil nut harvesting by the Kayapó people does not reduce recruitment of seedlings, but that harvesting and/or associated activities conducted by traditional harvesters may benefit B. excelsa beyond grove borders. Our study supports the hypothesis that B. excelsa dispersal throughout the Amazon was, at least in part, influenced by indigenous groups, and strongly suggests that current human management contributes to the maintenance and formation of B. excelsa groves. We suggest that changes in Brazil nut management practices by traditional people to prevent harvesting impacts may be unnecessary and even counterproductive in many areas, and should be carefully evaluated before implementation.     

Is it really you,Orthotrichum acuminatum? Ascertaining a new case of intercontinental disjunction in mosses

Intercontinental disjunct distributions are a main issue in current biogeography. Bryophytes usually have broad distribution ranges and therefore constitute an interesting subject of study in this context. During recent fieldwork in western North America and eastern Africa, we found new populations of a moss morphologically similar to Orthotrichum acuminatum. So far this species has been considered to be one of the most typical epiphytic mosses of the Mediterranean Basin. The new findings raise some puzzling questions. Do these new populations belong to cryptic species or do they belong to O. acuminatum, a species which then has a multiple‐continent disjunct range? In the latter case, how could such an intercontinental disjunction be explained? To answer these questions, an integrative study involving morphological and molecular approaches was conducted. Morphological results reveal that Californian and Ethiopian samples fall within the variability of those from the Mediterranean Basin. Similarly, phylogenetic analyses confirm the monophyly of these populations, showing that O. acuminatum is one of the few moss species with a distribution comprising the western Nearctic, the western Palaearctic and Palaeotropical eastern Africa. Pending a further genetic and phylogeographical study to support or reject the hypothesis, a process of long‐distance dispersal (LDD) is hypothesized to explain this distribution and the origin of the species is suggested to be the Mediterranean Basin, from where diaspores of the species may have migrated to California and Ethiopia. The spore release process in O. acuminatum is revisited to support the LDD hypothesis, © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 30–49.     

Sixteen hundred years of increasing tree cover prior to modern deforestation in Southern Amazon and Central Brazilian savannas

Tropical ecosystems are under increasing pressure from land‐use change and deforestation. Changes in tropical forest cover are expected to affect carbon and water cycling with important implications for climatic stability at global scales. A major roadblock for predicting how tropical deforestation affects climate is the lack of baseline conditions (i.e., prior to human disturbance) of forest–savanna dynamics. To address this limitation, we developed a long‐term analysis of forest and savanna distribution across the Amazon–Cerrado transition of central Brazil. We used soil organic carbon isotope ratios as a proxy for changes in woody vegetation cover over time in response to fluctuations in precipitation inferred from speleothem oxygen and strontium stable isotope records. Based on stable isotope signatures and radiocarbon activity of organic matter in soil profiles, we quantified the magnitude and direction of changes in forest and savanna ecosystem cover. Using changes in tree cover measured in 83 different locations for forests and savannas, we developed interpolation maps to assess the coherence of regional changes in vegetation. Our analysis reveals a broad pattern of woody vegetation expansion into savannas and densification within forests and savannas for at least the past ~1,600 years. The rates of vegetation change varied significantly among sampling locations possibly due to variation in local environmental factors that constrain primary productivity. The few instances in which tree cover declined (7.7% of all sampled profiles) were associated with savannas under dry conditions. Our results suggest a regional increase in moisture and expansion of woody vegetation prior to modern deforestation, which could help inform conservation and management efforts for climate change mitigation. We discuss the possible mechanisms driving forest expansion and densification of savannas directly (i.e., increasing precipitation) and indirectly (e.g., decreasing disturbance) and suggest future research directions that have the potential to improve climate and ecosystem models.     

Effectiveness of wood ash containing charcoal as a fertilizer for a forest plantation in a temperate region

Amendment of forest soils with mixed wood ash (MWA) generated in biomass power plants can prevent the depletion of soil nutrients that results from the intensive harvesting of forest plantations. Unlike fly wood ash, MWA contains charcoal and is characterized by a lower release of nutrients, so that it might be useful as a long term source of nutrients and soil organic matter. However, in order to use MWA as a fertilizer in forest systems, its effectiveness as regards supplying P and N must be improved. These aspects were studied in a 4 year-trial carried out in a Pinus radiata plantation. MWA was added alone or with mineral P, and the results were compared with those obtained with a combination of Ca(OH)₂ and mineral P. The application of MWA together with mineral P fertilizer increased the nutrient supply to the trees, as revealed by the changes in nutrient concentrations, lower values of resorption efficiencies and improved tree growth. The results showed that the amounts of Ca, Mg and K supplied by the MWA were suitable for maintenance of soil reserves. However, the presence of charcoal may have decreased the availability of P. The application of the MWA led to lower soil N mineralization rates and mineral N concentrations, which may affect N-limited systems. The use of density-dependent single tree increment models enabled the positive effects on tree growth of fertilization and thinning to be distinguished. For the treatments supplemented with mineral P, multiplicative factors of 1.13 to 1.15 can be applied to obtain post-thinning predictions of 4-year single-tree basal area increments. Although MWA can be used as a long term source of nutrients, charcoal temporarily reduces the availability of P and N.     

Viability and DNA Maintenance in Nonculturable Spiral Campylobacter jejuni Cells after Long-Term Exposure to Low Temperatures

Survival of Campylobacter jejuni at 4 and 20°C was investigated by using cellular integrity, respiratory activity, two-dimensional (2D) protein profile, and intact DNA content as indicators of potential viability of nonculturable cells. Intact DNA content after 116 days, along with cellular integrity and respiring cells, was detected for up to 7 months at 4°C by pulsed-field gel electrophoresis. Most changes in 2D protein profiles involved up- or down-regulation.     

Changes in lipid class and fatty acid composition during development in white seabream (Diplodus sargus) eggs and larvae

To establish the changes which occur during embryogenesis and early larvae development, eggs, yolk-sac larvae (one day old larvae) and absorbed yolk-sac larvae (three day old larvae) of white sea bream were examined for lipid class and fatty acid composition. The development was characterized by a decrease in all lipid classes with the exception of phosphatidylserine (PS) and fatty free acids (FFA) which increased, and sphingomyelin (SM) which remained unchanged. The changes observed in lipid class content and the decrease in fatty acids in total lipid (TL) reflect the utilization and mobilization of lipids during both embryogenesis and early larvae development. Fluctuations in the relative composition of fatty acids in phosphatidylcholine (PC) during development suggest a selective bulk uptake and catabolism of fatty acids in this lipid class. Unlike PC, catabolism of triacylglycerol (TG) fatty acid appears to be non-selective. During development, the decrease in levels of polyunsaturated fatty acids (PUFA) eicosapentaenoic (20:5n-3, EPA) and docosahexaenoic (22:6n-3, DHA) in total lipid denotes their utilization as energy substrate by Diplodus sargus larvae.     

A Predominant Multidrug-Resistant Salmonella enterica Serovar Saintpaul Clonal Line in German Turkey and Related Food Products

Recently, Salmonella enterica subsp. enterica serovar Saintpaul has increasingly been observed in several countries, including Germany. However, the pathogenic potential and epidemiology of this serovar are not very well known. This study describes biological attributes of S. Saintpaul isolates obtained from turkeys in Germany based on characterization of their pheno- and genotypic properties. Fifty-five S. Saintpaul isolates from German turkeys and turkey-derived food products isolated from 2000 to 2007 were analyzed by using antimicrobial agent, organic solvent, and disinfectant susceptibility tests, isoelectric focusing, detection of resistance determinants, plasmid profiling, pulsed-field gel electrophoresis (PFGE), and hybridization experiments. These isolates were compared to an outgroup consisting of 24 S. Saintpaul isolates obtained from humans and chickens in Germany and from poultry and poultry products (including turkeys) in Netherlands. A common core resistance pattern was detected for 27 German turkey and turkey product isolates. This pattern included resistance (full or intermediate) to ampicillin, amoxicillin-clavulanic acid, gentamicin, kanamycin, nalidixic acid, streptomycin, spectinomycin, and sulfamethoxazole and intermediate resistance or decreased susceptibility to ciprofloxacin (MIC, 2 or 1 μg/ml, respectively) and several third-generation cephalosporins (including ceftiofur and cefoxitin [MIC, 4 to 2 and 16 to 2 μg/ml, respectively]). These isolates had the same core resistance genotype, with bla_TEM-1, aadB, aadA2, sul1, a Ser83→Glu83 mutation in the gyrA gene, and a chromosomal class 1 integron carrying the aadB-aadA2 gene cassette. Their XbaI, BlnI, and combined XbaI-BlnI PFGE patterns revealed levels of genetic similarity of 93, 75, and 90%, respectively. This study revealed that a multiresistant S. Saintpaul clonal line is widespread in turkeys and turkey products in Germany and was also detected among German human fecal and Dutch poultry isolates.Over the last few decades, the emergence and spread of antimicrobial agent-resistant zoonotic bacteria has become a serious public health concern (2, 23). The widespread use of antimicrobial agents for disease control, including at the farm level, has increased selection of antimicrobial agent-resistant Salmonella isolates (1, 23, 44). Food animals are considered an important reservoir for resistant bacteria. These animals and food products derived from them are traded worldwide, which contributes to the global spread of zoonotic agents and antimicrobial resistance. In the last few years, several monitoring activities were initiated in order to generate baseline data on antimicrobial resistance in bacteria isolated from livestock and food derived from animals that could be used in future assessments of the risk of antimicrobial resistance (10).According to European Union (EU) Zoonoses Regulation (EC) no. 2160/2003 on the control of Salmonella and other specified food-borne zoonotic agents, a European Community target for reducing the prevalence of Salmonella in turkey flocks had to be established. Consequently, EU Commission decision 2006/662/EC was released, and a baseline survey of the prevalence of Salmonella in turkey flocks was carried out in all European countries, including Germany, over a 1-year period starting on 1 October 2006 (http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178706574172.htm). The main objective of this study was to estimate the prevalence of Salmonella in commercial flocks of turkeys. The data showed that at the EU level Salmonella enterica serovar Bredeney was the serovar reported most frequently for fattening turkey flocks and occurred in 17.2% of the samples from Salmonella-positive flocks (1,084 of 3,702 flocks were positive), followed by S. enterica serovar Hadar, S. enterica serovar Derby, and then S. enterica serovar Saintpaul (14.0%, 11.3%, and 10.4% of the samples from positive flocks, respectively). In this study, S. Saintpaul was detected in fattening turkeys in 12 countries, reflecting the wide spread of this serovar. Recently, S. Saintpaul has been increasingly observed in several countries, including Germany. According to Enter-Net reports (data on Salmonella human isolates identified by European national reference centers), for the last quarter of the year 2006 S. Saintpaul was the fourth most common serovar (1.6%) and, in contrast to the data for previous years, was one of the most frequent causes of human salmonellosis in Europe. After this, its prevalence was 1.2% and 0.6% in the first quarters of 2007 and 2008, respectively, among the Salmonella serotypes implicated in human disease (http://ecdc.europa.eu/en/publications/Pages/Surveillance_Reports.aspx). During the period from 2001 to 2009 in Germany, 463 cases of human salmonellosis related to S. Saintpaul (0.09% of all cases; the maximum prevalence was 0.15% in 2008, the prevalence was 0.1% in 2002, 2005, 2006, and 2009 and 0.06% in 2004, and the minimum prevalence was 0.05% in 2007) were reported to the Robert Koch Institute (Berlin, Germany) (www3.rki.de/SurvStat). In Germany, S. Saintpaul attracted public attention particularly in 1993, when it caused a nationwide food-borne outbreak (27). This serotype has often been related to outbreaks in other countries, and in 2008 it was implicated in a large multistate human outbreak associated with various vegetables in the United States (4).Previous studies showed that isolates of S. Saintpaul are often multidrug resistant (33, 35), but little is known about the mechanisms underlying antimicrobial resistance or about the pathogenic potential and epidemiology of isolates belonging to this serotype. The goals of this study were to obtain information about the resistance characteristics of isolates collected between 2000 and 2007 in Germany and to assess possible clonal relationships. The isolates used originated from turkey feces collected during the German Salmonella baseline study (in 2006 and 2007) or from diagnostic samples, including samples of turkey feces and turkey-related food products. These isolates were compared with German strains isolated from humans and chickens and with poultry strains isolated in Netherlands.     

The structure and matrix dynamics of bacterial biofilms as revealed by antimicrobial peptides' diffusion

From the biological point of view, bacterial biofilms are communities of bacteria embedded in a self-produced gel matrix composed of polysaccharides, DNA, and proteins. Considering the biophysical point of view, the biofilm matrix is a highly dense, crowded medium that imposes constraints to solute diffusion, depending on the size, conformational dynamics, and net charge. From the pharmacological point of view, biofilms are additional difficulties to drug development as heterogeneity in oxygen and nutrient distribution, and consequently, heterogeneity in bacterial metabolic status leads to recalcitrance. For peptide scientists, biofilms are both a challenge and an opportunity. Biofilms can be intruded by peptides, revealing important biological, biophysical, and pharmacological insights. Peptides can be engineered for different sizes, flexibilities, and net charges, unravelling the determinants of diffusion; they kill bacteria by lysis, overcoming the hurdles of metabolic status heterogeneity, and they are able to kill bacteria in the biofilm core, leaving the matrix intact, that is, without causing bacterial biofilm dispersion as side effect. This concise review addresses the knowledge reached while interrogating bacterial biofilms with peptides and other reporter molecules, and the advances therefrom in biology, biophysics, and drug development.     

Is Cassava the Answer to African Climate Change Adaptation?

This paper examines the impacts of climate change on cassava production in Africa, and questions whether cassava can play an important role in climate change adaptation. First, we examine the impacts that climate change will likely have on cassava itself, and on other important staple food crops for Africa including maize, millets, sorghum, banana, and beans based on projections to 2030. Results indicate that cassava is actually positively impacted in many areas of Africa, with ?3.7% to +17.5% changes in climate suitability across the continent. Conversely, for other major food staples, we found that they are all projected to experience negative impacts, with the greatest impacts for beans (?16%?±?8.8), potato (?14.7?±?8.2), banana (?2.5%?±?4.9), and sorghum (?2.66%?±?6.45). We then examined the likely challenges that cassava will face from pests and diseases through the use of ecological niche modeling for cassava mosaic disease, whitefly, brown streak disease and cassava mealybug. The findings show that the geographic distribution of these pests and diseases are projected to change, with both new areas opening up and areas where the pests and diseases are likely to leave or reduce in pressure. We finish the paper by looking at the abiotic traits of priority for crop adaptation for a 2030 world, showing that greater drought tolerance could bring some benefits in all areas of Africa, and that cold tolerance in Southern Africa will continue to be a constraint for cassava despite a warmer 2030 world, hence breeding needs to keep a focus on this trait. Importantly, heat tolerance was not found to be a major priority for crop improvement in cassava in the whole of Africa, but only in localized pockets of West Africa and the Sahel. The paper concludes that cassava is potentially highly resilient to future climatic changes and could provide Africa with options for adaptation whilst other major food staples face challenges.