Characterization of Soil Bacterial Assemblies in Brazilian Savanna-Like Vegetation Reveals Acidobacteria Dominance

The Brazilian Cerrado is the second largest biome in Brazil and is considered a biodiversity hotspot. In this work, we compared the bacterial communities in Cerrado soil associated with four types of native vegetation (Cerrado Denso, Cerrado sensu stricto, Campo Sujo, and Mata de Galeria) by ribosomal RNA intergenic spacer analysis, terminal fragment restriction length polymorphism and pyrosequencing. The fingerprinting results were very similar. The bacterial communities of Cerrado Denso and Cerrado sensu stricto grouped together and were distinct from those in Campo Sujo and Mata de Galeria. Pyrosequencing generated approximately 40,000 16S rRNA gene sequences per sample and allowed the identification of 17 phyla in soil samples under Cerrado vegetation. Acidobacteria were dominant in all areas studied with a relative frequency of 40-47?%, followed closely by Proteobacteria accounting for 34-40?% of the sequences. Results from all molecular techniques used suggested that the bacterial communities of Cerrado sensu stricto and Cerrado Denso are very similar to each other, while Campo Sujo forms a separate group, and Mata de Galeria is the most distinct with higher species richness. This is the first extensive study of native Cerrado soil microbiota, an important but endangered biome.     

Water availability determines physiognomic gradient in an area of low-fertility soils under Cerrado vegetation

Soil is one of the environmental elements to influence Cerrado vegetation. Aluminum toxicity of Cerrado soils is well known, but the importance of water availability is still to be understood, especially in Cerrado under wetter climates. We studied the association between Cerrado physiognomies (cerrado sensu stricto and cerradão) and morphological, chemical, physical, and physical–hydrical soil attributes at southwestern São Paulo State, Brazil. Characterization of soil morphology, classification and sample collection for particle-size distribution, and chemical and water-retention analyses were carried out in 15 permanent plots, where vegetation was characterized floristically and structurally. Simple correlation and canonical correspondence analyses were performed with soil data. Classification of soils (U.S. Soil Taxonomy) with very low clay contents was not able to separate soils under cerradão—forestry physiognomy—from those under cerrado sensu stricto—savannic physiognomy, even though it tends to distinguish soils under greater biomass from those under lower biomass physiognomies. High soil acidity of all studied soils and increased at the sites with greater contents of organic matter, mainly with the cerradão physiognomy, precluded Al toxicity as a cause of the physiognomic gradient within Cerrado. Clay content, microporosity, and residual and saturation moisture were the most significant soil attributes to correlate directly with the cerradão physiognomy, indicating that water availability is the main factor explaining the physiognomic gradient of Cerrado vegetation in a local scale, where climate and soil fertility do not vary spatially.     

Mutual affinities of Santalalean families

The paper represents a reassessment of familial relationships within the Order Santalales. Rafflesiaceae, Hydnoraceae, and Balanophoraceae are excluded from the order, and their reproductive similarities with some Santalales regarded as evolutionary convergence. The exclusion of Grubbiaceae from Santalales sponsored by other workers is accepted, as is the reassignment to other families of the two only genera of Octoknemaceae. The remaining members of the order are placed into six families, viz. Olacaceae (possibly representing several smaller families); Santalaceae; Loranthaceae (sensu stricto); Viscaceae (sensu stricto); Myzodendraceae ; and Eremolepidaceae (containingEremolepis, Eubrachion, andAntidaphne). It is suggested thatLepidoceras, formerly placed near the above three genera, is more properly placed in Loranthaceae (sensu stricto) nearTupeia. The proposed scheme of affinities of the families of Santalales, as reconstituted, is based to a large extent on inflorescence structure, but is supported by floral morphology and other features. The thesis is defended that Loranthaceae (sensu stricto), Santalaceae, Myzodendraceae, and Eremolepidaceae represent four inde pendent lines of development from portions of the Olacacean complex. Viscaceae (sensu stricto) may be derived directly from Santalaceae.     

Microbial Diversity in Cerrado Biome (Neotropical Savanna) Soils

The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture.     

Species distribution and antifungal susceptibility among clinical isolates of Candida parapsilosis complex from India

Background

Candida parapsilosis is recognized as a species complex: Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis are three distinct but closely related species.

Open vegetation formations (grasslands and savannahs) support a higher diversity of Cetoniidae (Insecta: Coleoptera) than forest formations in the brazilian Cerrado

Brazil has 22 genera and 75 species of Cetoniidae, with the Cerrado hosting the greatest diversity among Brazilian biomes. However, the diversity of groups among the different phytophysiognomies of the biome is not known. The objectives of this study are to assess Cetoniidae diversity and to verify the seasonality of these beetles in three Cerrado phytophysiognomies (gallery forest, cerrado sensu stricto, and campo sujo) located in three conservation units in Brasilia, Distrito Federal, Brazil. We collected adults monthly (October/2016 to September/2018) using 180 traps baited with bananas fermented with sugarcane juice, totaling 1,574 specimens, 8 genera, and 17 species. Cetoniidae diversity was higher in the phytophysiognomies with lower tree density (campo sujo and cerrado sensu stricto) than in gallery forests (forest formation), confirming our hypothesis that more open areas favor the dispersal of these insects due to their diurnal long-flying behavior. The seasonality of Cetoniidae was directly related to the precipitation, with higher numbers of individuals and species in the rainy season. However, the distribution varies among the phytophysiognomies, with aggregated distribution in campo sujo and gallery forest and dispersed in cerrado sensu stricto. Our results suggest that the Cetoniidae take advantage of the open Cerrado physiognomies to locate resources faster and with less energy expenditure, presenting higher diversity in these environments, despite the more ephemeral and dispersed food resources.

     

Entomopathogenic nematode distribution and edaphoclimatic conditions in the Cerrado of Minas Gerais,Brazil

Based on the high diversity of Brazilian fauna and flora, edaphoclimatic conditions in the Cerrado of Minas Gerais, and the situation of utilization of EPNs in Brazil, a survey was conducted in order to relate the presence of these organisms with the physical and chemical attributes of the soil, combined with precipitation. To this end, soil samples were collected in areas with diversified vegetation types in Monte Carmelo, MG, at Juliana Farm. The samples were obtained every 15 days for 6 months. From each spot, soil samples (about 500 g) were collected for soil moisture characterization, nematode isolation and determination of pH, organic matter, potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), potential acidity (H + Al) and precipitation data (mm). Three populations of entomopathogenic nematodes of the Heterorhabditis amazonensis species were isolated in Cerrado stricto sensu and Gallery forest areas. The occurrence H. amazonensis could not be considered restricted to specific soil condition, as organic matter, humidity, pH, Ca, K, Mg and H + Al, especially considering the organic matter and K values, which had variable levels between the places of collection. The p values of the positive soil samples were at a lower level than the mean of the Gallery forest and Cerrado, and at the same level as maize and pasture area. The soil moisture in the Cerrado area increased with the higher values of precipitation; however, in the Gallery forest area this association was not observed. Also, the nematodes were isolated when the temperature began to decrease.     

Outcome of experimental porcine circovirus type 1 infections in mid-gestational porcine foetuses

Background

Lyme disease caused by Borrelia burgdorferi sensu lato complex is an important endemic zoonosis whose distribution is closely related to the main ixodid tick vectors. In China, isolated cases of Lyme disease infection of humans have been reported in 29 provinces. Ticks, especially ixodid ticks are abundant and a wide arrange of Borrelia natural reservoirs are present. In this study, we developed a reverse line blot (RLB) to identify Borrelia spp. in ticks collected from sheep and cattle in 7 Provinces covering the main extensive livestock regions in China.

Results

Four species-specific RLB oligonucleotide probes were deduced from the spacer region between the 5S-23S rRNA gene, along with an oligonucleotide probe which was common to all. The species specific probes were shown to discriminate between four genomic groups of B. burgdorferi sensu lato i.e. B. burgdorferi sensu stricto, B. garinii, B. afzelii, and B. valaisiana, and to bind only to their respective target sequences, with no cross reaction to non target DNA. Furthermore, the RLB could detect between 0.1 pg and 1 pg of Borrelia DNA. A total of 723 tick samples (Haemaphysalis, Boophilus, Rhipicephalus and Dermacentor) from sheep and cattle were examined with RLB, and a subset of 667 corresponding samples were examined with PCR as a comparison. The overall infection rate detected with RLB was higher than that of the PCR test. The infection rate of B. burgdoreri sensu stricto was 40% in south areas; while the B. garinii infection rate was 40% in north areas. The highest detection rates of B. afzelii and B. valaisiana were 28% and 22%, respectively. Mixed infections were also found in 7% of the ticks analyzed, mainly in the North. The proportion of B. garinii genotype in ticks was overall highest at 34% in the whole investigation area.

Conclusion

In this study, the RLB assay was used to detect B. burgdorferi sensu lato in ticks collected from sheep and cattle in China. The results showed that B. burdorferi senso stricto and B. afzelii were mainly distributed in the South; while B. garinii and B. valaisiana were dominant in the North. Borrelia spirochaetes were detected in Rhipicephalus spp for the first time. It is suggested that the Rhipicephalus spps might play a role in transmitting Borrelia spirochaetes.     

<Emphasis Type="Italic">Chamaecrista elata</Emphasis> (Leguminosae,Caesalpinioideae), a new species from the highlands of Goiás,Brazil

During the course of a taxonomic study of Chamaecrista sect. Absus subsect. Absus ser. Rigidulae, a new species of Chamaecrista was discovered growing in disturbed areas of Cerrado sensu stricto in the municipality of Alto Paraíso de Goiás. Chamaecrista elata is herein described and illustrated. Morphological comparison with related species and information on geographical distribution, environmental preferences, conservation status, and phenology are provided.     

<Emphasis Type="Italic">Candida haemulonii</Emphasis> sensu lato: Update of the Determination of Susceptibility Profile in Argentina and Literature Review

Purpose of review

This review summarizes the information available of Candida haemulonii sensu lato, and updates the in vitro susceptibility profile of the isolates of these species from Argentina. C. haemulonii sensu lato causes fungemia in low frequency in adults and children; however, the knowledge about this emerging yeast is relevant since it is considered as a multi-resistant pathogen.

Recent findings

The discovery of new antifungal molecules, the determination of epidemiological cutoff value and clinical breakpoints for some yeasts of clinical impact, and the update of techniques to determine the in vitro susceptibility profile to yeast have generated some available information, although, for C. haemulonii sensu lato, this information is not always useful for clinical application.

Summary

We determined the susceptibility profile of C. haemulonii sensu lato strains isolated in Argentina, as a first step to establish the epidemiological cutoff values in our region. We also review the current situation in other countries.

     

Coronary microcirculatory dysfunction is associated with left ventricular dysfunction during follow-up after STEMI

Background

Coronary microvascular resistance is increased after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI), which may be related in part to changed left ventricular (LV) dynamics. Therefore we studied the coronary microcirculation in relation to systolic and diastolic LV function after STEMI.

Methods

The study cohort consisted of 12 consecutive patients, all treated with primary PCI for a first anterior wall STEMI. At 4 months, we assessed pressure-volume loops. Subsequently, we measured intracoronary pressure and flow velocity and calculated coronary microvascular resistance. Infarct size and LV mass were assessed using magnetic resonance imaging.

Results

Patients with an impaired systolic LV function due to a larger myocardial infarction showed a higher baseline average peak flow velocity (APV) than the other patients (26?±?7 versus 17?±?5 cm/s, p?=?0.003, respectively), and showed an impaired variable microvascular resistance index (2.1?±?1.0 versus 4.1?±?1.3 mmHg?cm^?1?s^?1, p?=?0.003, respectively). Impaired diastolic relaxation time was inversely correlated with hyperaemic APV (r?=??0.56, p?=?0.003) and positively correlated with hyperaemic microvascular resistance (r?=?0.48, p?=?0.01). LV dilatation was associated with a reduced variable microvascular resistance index (r?=?0.78, p?=?0.006).

Conclusion

A larger anterior myocardial infarction results in impaired LV performance associated with reduced coronary microvascular resistance variability, in particular due to higher coronary blood flow at baseline in these compromised left ventricles.     

Metabolomics as a tool for understanding the evolution of <Emphasis Type="Italic">Tabebuia sensu lato</Emphasis>

Background

Plant systematic studies have changed substantially in the last years, stimulated by new strategies for phylogenetic studies. In this regard, chemistry data has been a useful tool for understanding plant phylogenetic relationships.

Objective

Our aim was to apply metabolomic approaches, followed by multivariate statistical analysis and dereplication of Tabebuia sensu lato species, and compare our results with classifications based on traditional taxonomy and molecular phylogeny. We also evaluated the application of metabolomics as a chemotaxonomic identification tool, as well as to enlighten plant chemical evolution.

Methods

Metabolomic data was generated through a high-resolution mass spectrometry with electrospray ionization of 27 Tabebuia sensu lato specimens from different populations, consisting of 15 Handroanthus (from four species) and 12 Tabebuia sensu stricto (from three species). Chemometric tools, such as principal component analysis and metabolite heatmaps, were used to scrutinize the metabolic changes among species.

Results

Tabebuia and Handroanthus species presented different secondary metabolite storage capacity. The genus Tabebuia revealed higher levels of glycosylated iridoids esterified with a phenylpropanoid moiety, such as specioside, verminoside, and minecoside, while Handroanthus accumulated iridoids linked to a simple phenol, lignans, and verbascoside derivatives.

Conclusion

These results corroborate splitting the Tabebuia s.l., which was supported by profound changes in secondary metabolism, suggesting metabolomics as an excellent tool for understanding species evolution.

     

A randomization method for efficiently and accurately processing fine roots, and separating them from debris, in the laboratory

Background and Aims

We developed a method for processing roots from soil cores and monoliths in the laboratory to reduce the time and cost devoted to separating roots from debris and improve the accuracy of root variable estimates. The method was tested on soil cores from a California oak savanna, with roots from trees, Quercus douglasii, and annual grasses.

Methods

In the randomized sampling method, one isolates the sample fraction consisting of roots and organic debris?<?= 1 cm in length, and randomizes it through immersion in water and vigorous mixing. Sub-samples from the mixture are then used to estimate the percentage of roots in this fraction, thereby enabling an estimate of total sample biomass.

Results

We found that root biomass estimates, determined through the randomization method, differed from total root biomass established by meticulously picking every root from a sample with an error of 3.0 % +/? 0.6 %?s.e.

Conclusions

This method greatly reduces the time and resources required for root processing from soil cores and monoliths, and improves the accuracy of root variable estimates compared to standard methods. This gives researchers the ability to increase sample frequency and reduce the error associated with studying roots at the landscape and plant scales.     

Contribution of biological nitrogen fixation to Elephant grass (Pennisetum purpureum Schum.)

Aims

Because of its high dry matter (DM) productivity, elephant grass (Pennisetum purpureum) is an ideal candidate for biomass production for biofuel production if low N fertilizer rates are used to avoid high fossil fuel inputs. The objective of this study was to investigate the potential of different elephant grass genotypes to obtain contributions of plant-associated biological N₂ fixation (BNF).

Methods

Three field experiments with 4 or 5 different genotypes were conducted on low-fertility Acrisols, two in Rio de Janeiro State and one in Espirito Santo for the evaluation of DM and N accumulation and ¹⁵N abundance.

Results

DM and N accumulation rates of four genotypes in the two experiments in Rio State stabilized at high levels after 2?years of growth. In all experiments the spontaneously-occurring weeds in the plots were significantly higher in ¹⁵N abundance than the elephant grass genotypes. The lower ¹⁵N abundance of the elephant grass was shown not to be due to lower δ¹⁵N abundance at depth in the soil.

Conclusions

Four of the grass genotypes obtained between 18 and 70% of their N from BNF amounting to inputs of between 36 and 132?kg N ha^?1?yr^?1.     

Zinc fluxes into developing barley grains: use of stable Zn isotopes to separate root uptake from remobilization in plants with contrasting Zn status

Background and Aims

Zn imported into developing cereal grains originates from either de novo Zn uptake by the roots or remobilization of Zn from vegetative tissues. The present study was focused on revealing the quantitative importance of the two pathways for grain Zn loading and how their relative contribution varies with the overall plant Zn status.

Methods

The stable isotope ⁶⁷Zn was used to trace Zn uptake and remobilization fluxes in barley (Hordeum vulgare L.) plants growing in hydroponics at 0.1?μM (low Zn), 1.5?μM (medium Zn) or 5?μM Zn (high Zn). When grain development reached 15?days after pollination the Zn source was changed to an enriched ⁶⁷Zn isotope and plants were harvested after 6 to 48?h. Zn concentrations and isotope ratios were determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).

Results

Plants with low Zn status absorbed 3-fold more Zn than plants with medium or high Zn status when roots were exposed to an external concentration of 1.5?μM ⁶⁷Zn. Stems and ears were the primary recipients of the de novo incorporated Zn with preferential allocation to the developing grains over time. The leaves received in all cases a very small proportion (<5?%) of the newly absorbed Zn and the proportion did not increase over time. Zn fluxes derived from uptake and remobilization were almost equal in plants with low Zn status, while at high Zn status remobilization delivered 4 times more Zn to the developing grains than did root Zn uptake.

Conclusions

Stable isotopes in combination with ICP-MS provided a strong tool for quantification of Zn fluxes in intact plants. The importance of Zn remobilization compared to de novo root absorption of Zn increased with increasing plant Zn status. Very little de novo absorbed Zn was translocated to the leaves during generative growth stages.     

Quantifying the effect of soil compaction on three varieties of wheat (Triticum aestivum L.) using X-ray Micro Computed Tomography (CT)

Aims

X-ray Micro Computed Tomography (CT) enables interactions between roots and soil to be visualised without disturbance. This study examined responses of root growth in three Triticum aestivum L. (wheat) cultivars to different levels of soil compaction (1.1 and 1.5?g?cm^?3).

Methods

Seedlings were scanned 2, 5 and 12?days after germination (DAG) and the images were analysed using novel root tracking software, RootViz3D?, to provide accurate visualisation of root architecture. RootViz3D? proved more successful in segmenting roots from the greyscale images than semi-automated segmentation, especially for finer roots, by combining measurements of pixel greyscale values with a probability approach to identify roots.

Results

Root density was greater in soil compacted at 1.5?g?cm^?3 than at 1.1?g?cm^?3 (P?=?0.04). This effect may have resulted from improved contact between roots and surrounding soil. Root diameter was greater in soil at a high bulk density (P?=?0.006) but overall root length was reduced (P?=?0.20). Soil porosity increased with time (P?<?0.001) in the uncompacted treatment.

Conclusions

RootViz3D? root tracking software in X-ray CT studies provided accurate, non-destructive and automated three dimensional quantification of root systems that has many applications for improving understanding on root-soil interactions.     

PeanutDB: an integrated bioinformatics web portal for Arachis hypogaea transcriptomics

Background

Doubled haploid production is a key technology in triticale research and breeding. A critical component of this method depends on chromosome doubling, which is traditionally achieved by in vivo treatment of seedlings with colchicine.

Results

In this study we investigated the applicability of an in vitro approach for chromosome doubling based on microspore culture. Our results show a pronounced increase in the proportion of doubled haploid triticale plants compared to the spontaneous doubling rate, but also compared to the doubling obtained by the standard in vivo approach. In addition, the frequency of plants surviving from culture medium to maturity is also much higher for the in vitro approach. Colchicine concentrations of 1?mM for 24?h or 0.3?mM applied for 48 or 72?h during the first hours of microspore culture performed best.

Conclusions

Our results suggest that for triticale, in vitro chromosome doubling is a promising alternative to the in vivo approach.     

L’insémination artificielle avec donneur: les enfants donnent leur avis

Abstract

A study has recently been carried out in France on adults (both men and women) conceived by donor insemination.

Method

Twenty-one subjects were interviewed about shared aspects of their experience by a psychologist (the present author) working for CECOS (Centre d’étude et de conservation des ?ufs et du sperme humains).

Results

It was found that the subjects had much in common, while remaining individually distinctive in terms of their relationships with their parents.

Conclusion

Most of the subjects felt that, by and large, their parents had been right to choose this method. The majority also considered that the anonymity of sperm donation was a good thing.