Frugivory by the fish Brycon hilarii (Characidae) in western Brazil

Frugivory and seed dispersal have been poorly studied in Neotropical freshwater fishes. We studied frugivory and seed dispersal by the piraputanga fish (Brycon hilarii, Characidae) in the Formoso River, Bonito, western Brazil. We examined the stomach contents of 87 fish and found the diet of piraputanga consisted of 24% animal prey (arthropods, snails, and vertebrates), 31% seeds/fruits and 45% other plant material (algae/macrophytes/leaves/flowers). The piraputangas fed on 12 fruit species, and were considered as seed dispersers of eight species. Fruits with soft seeds larger than 10 mm were triturated, but all species with small seeds (e.g. Ficus, Psidium) and one species with large hard seed (Chrysophyllum gonocarpum) were dispersed. Piraputangas eat more fruits in the dry season just before the migration, but not during the spawning season. Fish length had a positive relation with the presence of fruits in their guts. The gallery forest of the Formoso River apparently does not have any plant species that depend exclusively on B. hilarii for seed dispersal because all fruit species are also dispersed by birds and mammals. Based on seed size and husk hardness of the riparian plant community of Formoso River, however, the piraputangas may potentially disperse at least 50% of the riparian fleshy fruit species and may be particularly important for long-distance dispersal. Therefore, overfishing or other anthropogenic disturbances to the populations of piraputanga may have negative consequences for the riparian forests in this region.     

A banking strategy toward customized therapy in breast cancer

In breast cancer, various clinical parameters are assessed to define clinical stage and thus obtain a more accurate prognosis. However, banks of tumor tissues are an important source of material for studies of risk of recurrence and of features governing clinical outcome in breast cancer. Although the heterogeneous characteristics of individual tumors, subtle phenotypes and stem cells can only be identified in viable cells, tissue banks often give low priority to the preservation of living cells because it is labor-intensive and expensive. The present study was designed to evaluate the feasibility of introducing, within the routine procedures of tissue preservation, a cryopreservation protocol that allows the recovery of living cells after storage. We analyzed the effect of storage time on cell viability, growth rates, and protein expression of ten human breast cancer specimens subjected to various cryopreservation techniques. Cryopreservation of cancer tissue specimens for 12 months allowed protein characterization but not the recovery of living cells. Here we show that enzymatic digestion immediately before slow freezing, and storage in liquid nitrogen permits the recovery and expansion of living cells that can be tailored to specific requirements and projects.     

Self-fertility and polyembryony in South American yellow trumpet trees (Handroanthus chrysotrichus and H. ochraceus, Bignoniaceae): a histological study of postpollination events

Handroanthus chrysotrichus shows pollination-dependent self-fertility, polyploidy, and adventitious polyembryony, and it is closely related to H. ochraceus, for which apparently conflicting reports of self-incompatibility and apomixis have been published. The present study aims to investigate the polyembryony in these species by means of histological analysis of ovule/seed development in unpollinated, selfed, and crossed pistils/fruits (in H. chrysotrichus only) as well as seed germination experiments. Experimental pollinations were carried out to evaluate breeding systems in the studied populations, and the results indicated self-fertility in both species. Adventitious embryo precursor cells (AEPs) were formed in the ovules of unpollinated, selfed, and crossed pistils. However, unfertilized ovules never develop into seeds, and fertilization/endosperm initiation clearly stimulates the formation of AEPs in pollinated pistils. The inability of AEP-bearing unfertilized ovules to initiate endospermogenesis clearly shows that fertilization is needed for adventitious embryo development. Consequently, formation of AEPs is required but is not sufficient for apomictic reproduction in H. chrysotrichus. Analysis of the positions of multiple embryos in the endosperm indicated that fertilized ovules are able to develop into seeds even in the absence of a zygotic embryo. The development of AEPs in ovules of H. chrysotrichus foregoes the stage in which activation of selfed pistil rejection takes place in H. impetiginosus, a species with late-acting self-incompatibility. Our study supports the hypothesis that the self-fertility in H. chrysotrichus (and perhaps also in H. ochraceus) resulted from the emergence of pseudogamous apomixis, favored by the physiological peculiarities of the late-acting self-incompatibility and possibly related to polyploidy.     

Drought-induced variations of water relations parameters in Olea europaea

The effects of water stress on water potential components, tissue water content, mean elastic modulus and the osmoregulation capacity of olive (Olea europaea L. cv. Coratina) leaves was determined. Artificial rehydration of olive leaf tissues altered the P-V relationships so that a plateau phenomenon occurred. Points in the P-V curve in the region affected by the plateau, generally up to –0.5 MPa, were corrected for all the samples analyzed. In the corrected P-V relationship, an osmotic adjustment was found in drought-stressed leaf tissues. Osmotic potentials at full turgor (_{0 (sat)}) and osmotic potential at turgor-loss (_{0 (TVT)}) decreased from –2.06±0.01 MPa and –3.07±0.16 MPa in controls to –2.81±0.03 MPa and –3.85±0.12 MPa in most stressed plants. Osmotic adjustment values obtained from the P-V curves agreed with those obtained using an osmometer. An active osmotic adjustment of 1.42 MPa was also observed in 1–4 mm- diameter roots. Mannitol is the main carbohydrate involved in osmotic potential decrease in all treatments. The maximum elastic modulus increased from 11.6±0.95 MPa in the controls to 18.6±0.61 MPa in the most stressed plants.     

Proliferation and Differentiation of Trypanosoma cruzi inside Its Vector Have a New Trigger: Redox Status

Trypanosoma cruzi proliferate and differentiate inside different compartments of triatomines gut that is the first environment encountered by T. cruzi. Due to its complex life cycle, the parasite is constantly exposed to reactive oxygen species (ROS). We tested the influence of the pro-oxidant molecules H₂O₂ and the superoxide generator, Paraquat, as well as, metabolism products of the vector, with distinct redox status, in the proliferation and metacyclogenesis. These molecules are heme, hemozoin and urate. We also tested the antioxidants NAC and GSH. Heme induced the proliferation of epimastigotes and impaired the metacyclogenesis. β-hematin, did not affect epimastigote proliferation but decreased parasite differentiation. Conversely, we show that urate, GSH and NAC dramatically impaired epimastigote proliferation and during metacyclogenesis, NAC and urate induced a significant increment of trypomastigotes and decreased the percentage of epimastigotes. We also quantified the parasite loads in the anterior and posterior midguts and in the rectum of the vector by qPCR. The treatment with the antioxidants increased the parasite loads in all midgut sections analyzed. In vivo, the group of vectors fed with reduced molecules showed an increment of trypomastigotes and decreased epimastigotes when analyzed by differential counting. Heme stimulated proliferation by increasing the cell number in the S and G2/M phases, whereas NAC arrested epimastigotes in G1 phase. NAC greatly increased the percentage of trypomastigotes. Taken together, these data show a shift in the triatomine gut microenvironment caused by the redox status may also influence T. cruzi biology inside the vector. In this scenario, oxidants act to turn on epimastigote proliferation while antioxidants seem to switch the cycle towards metacyclogenesis. This is a new insight that defines a key role for redox metabolism in governing the parasitic life cycle.     

HCV Genotypes,Characterization of Mutations Conferring Drug Resistance to Protease Inhibitors,and Risk Factors among Blood Donors in S?o Paulo,Brazil

Background

Hepatitis C virus (HCV) infection is a global health problem estimated to affect almost 200 million people worldwide. The aim of this study is to analyze the subtypes and existence of variants resistant to protease inhibitors and their association with potential HCV risk factors among blood donors in Brazil.

Methods

Repeat anti-HCV reactive blood donors are systematically asked to return for retest, notification, and counseling in which they are interviewed for risk factors for transfusion-transmitted diseases. We analyzed 202 donors who returned for counseling from 2007 to 2010 and presented enzyme immunoassay- and immunoblot-reactive results. The HCV genotypes and resistance mutation analyses were determined by the direct sequencing of the NS5b and NS3 regions, respectively. The HCV viral load was determined using an in-house real-time PCR assay targeting the 5′-NCR.

Results

HCV subtypes 1b, 1a, and 3a were found in 45.5%, 32.0%, and 18.0% of the donors, respectively. The mean viral load of genotype 1 was significantly higher than that of the genotype 3 isolates. Subtype 1a was more frequent among young donors and 3a was more frequent among older donors. Protease inhibitor-resistant variants were detected in 12.8% of the sequenced samples belonging to genotype 1, and a higher frequency was observed among subtype 1a (20%) in comparison to 1b (8%). There was no difference in the prevalence of HCV risk factors among the genotypes or drug-resistant variants.

Conclusions

We found a predominance of subtype 1b, with an increase in the frequency of subtype 1a, in young subjects. Mutations conferring resistance to NS3 inhibitors were frequent in treatment-naïve blood donors, particularly those infected with subtype 1a. These variants were detected in the major viral population of HCV quasispecies, have replicative capacities comparable to nonresistant strains, and could be important for predicting the response to antiviral triple therapy.     

Issues of banking breast cancer cells to generate mammospheres

Identification of breast cancer stem cells, within the context of the tumor tissue, requires an efficient and standardized method to preserve the functional features of living cells. Although isolating cancer stem cells can be laborious and time-consuming, minimal processing may be advantageous for the banking of specimens from which cultures are not immediately needed. Homogenization of banking procedures will result in a reliable network of biorepositories for cooperative studies and several research groups are focusing on the issues of tissue banks for translational medicine. Most tissue banks collect and freeze unprocessed cancer specimens, which cannot therefore be used to generate viable cells. We discuss the principal issues of biobanking breast cancer living cells and protocols for mammospheres formation from single cell suspension of tumor cells.     

Targeted sequencing supports morphology and embryo features in resolving the classification of Cyperaceae tribe Fuireneae s.l.

Molecular phylogenetic studies based on Sanger sequences have shown that Cyperaceae tribe Fuireneae s.l. is paraphyletic. However, taxonomic sampling in these studies has been poor, topologies have been inconsistent, and support for the backbone of trees has been weak. Moreover, uncertainty still surrounds the morphological limits of Schoenoplectiella, a genus of mainly small, amphicarpic annuals that was recently segregated from Schoenoplectus. Consequently, despite ample evidence from molecular analyses that Fuireneae s.l. might consist of two to four tribal lineages, no taxonomic changes have yet been made. Here, we use the Angiosperms353 enrichment panel for targeted sequencing to (i) clarify the relationships of Fuireneae s.l. with the related tribes Abildgaardieae, Eleocharideae, and Cypereae; (ii) define the limits of Fuireneae s.s., and (iii) test the monophyly of Fuireneae s.l. genera with emphasis on Schoenoplectus and Schoenoplectiella. Using more than a third of Fuireneae s.l. diversity, our phylogenomic analyses strongly support six genera and four major Fuireneae s.l. clades that we recognize as tribes: Bolboschoeneae stat.nov., Fuireneae s.s., Schoenoplecteae, and Pseudoschoeneae tr. nov. These results are consistent with morphological, micromorphological (nutlet epidermal cell shape), and embryo differences detected for each tribe. At the generic level, most sub-Saharan African perennials currently treated in Schoenoplectus are transferred to Schoenoplectiella. Our targeted sequencing results show that these species are nested in Schoenoplectiella, and their treatment here is consistent with micromorphological and embryo characters shared by all Schoenoplectiella species. Keys to recognized tribes and genera are provided.     

Evaluating success of various restorative interventions through drone‐ and field‐collected data,using six putative framework species in Argentinian Patagonia

Field data and unmanned aerial vehicles, also known as drones, were used to analyze a long‐term experiment in a severely degraded area of the “Monte,” one of the most arid and degraded biomes in Argentina. Field methods and drone orthoimages obtained from flights of a quadcopter at 20 and 40 m were used to compare plantation plots versus natural recovery on scarified sites, and the field performance of six putative framework species under four different treatments was evaluated. After 5 years of recovery in soils with almost no organic matter and mean annual rainfall averaging 145 mm, plantation plots had high survival rates (>65%) for all species as determined through both field survey and drone imagery. Three species were planted with a greater number of seedlings due to their availability in nurseries. For these species experimental treatments were studied statistically. Independently of treatment applied (control; 1/2 L hydrogel; 1 L hydrogel; 1 L of hydrogel + 1/2 kg of organic compost), highest survival rates were found for P. flexuosa var. depressa (88% ± 14.8) and A. lampa (84% ± 14.8). Drone images and field data both showed that these two putative framework species had the highest plant cover. In sharp contrast, mechanical scarification without planting or other treatments induced very low recovery (<2%). We demonstrate that drone imagery provides a new and very valuable tool for evaluating and monitoring restorative interventions in drylands.