Growth of Hydrilla verticillata (L.f.) Royle under controlled conditions

Aquatic macrophytes are important resources for the maintenance of trophic chains and in biogeochemical processes, but they can also be deleterious for several uses if present in excess. Hydrilla verticillata was found in the Paraná River (Brazil) after 2005, which requires monitoring owing to the invasive potential of this species. In this study, we measured the growth of H. verticillata under controlled conditions and compared the growth dynamics for the two development strategies (branch and tuber). We show that this species has great potential to develop in tropical (Brazilian) aquatic ecosystems. The parameters from the modelling of the growth kinetics indicated a doubling time of 19.8 days for H. verticillata growing from stems; however, the growth from tubers were much faster, with doubling times ranging from 2.5 to 11 days. The delay for the tubers to sprout caused a decrease in the number of branches of H. verticillata stems. From the growth parameters obtained from the experiments under controlled conditions, we concluded that the high temperature and light availability in most South American reservoirs (including the Porto Primavera Reservoir where it was first recorded) are suitable for H. verticillata to compete and probably displace other native aquatic macrophytes, such as Egeria najas, Egeria densa, and Cerathophyllum demersum. This is a matter of concern because these and other submersed species are commonly found in several natural and man-made South-American aquatic ecosystems, where they are key for biodiversity maintenance.     

Younger siblings play a major role in Helicobacter pylori transmission among children from a low-income community in the Northeast of Brazil

Background and Aims: To further evaluate intrafamilial transmission of H. pylori infection during childhood, we investigated the prevalence of H. pylori in family members from a poor H. pylori high‐prevalence urban community in the Northeast of Brazil. Methods: H. pylori infection was investigated in 570 members of 128 households, by ¹³C‐urea breath test in children and by ELISA in mothers and other adult relatives. Results: The overall prevalence of H. pylori infection (376/570) increased with age (p < .001) and ranged from 28.9%, in children aged 6 months to 5 years, to 82% in adults over 40 years. An H. pylori positive mother and the number of infected siblings are independent risk factors for childhood H. pylori infection (OR = 2.2, 95% CI = 1.0–4.6 and OR = 4.3, 95% CI = 2.3–8.1, respectively) The number of siblings, number of younger siblings, and number of infected younger siblings were also associated with the infection in the univariate analysis. The number of infected younger siblings remained independently associated with the infection (p = .000), even after controlling for all the above cited variables, in addition to the H. pylori status of siblings and mothers, age, number of people per room, and number of children in the household. Conclusion: The transmission of H. pylori occurs from infected mothers to their offspring and among siblings, notably from younger siblings to the older ones.     

Antiprotozoal,Schistosomicidal, and Antimicrobial Activities of the Essential Oil from the Leaves of Baccharis dracunculifolia

Baccharis dracunculifolia DC. (Asteraceae), popularly known as ‘alecrim do campo’, is a native plant from Brazil used in folk medicine as febrifuge, anti‐inflammatory, antiseptic, and to treat skin sores. Also, B. dracunculifolia is the most important plant source of the Brazilian green propolis, which is recognized for its antiseptic and antiprotozoal activities. This study aimed at investigating the in vitro antiprotozoal, schistosomicidal, and antimicrobial activities of the essential oil from the leaves of B. dracunculifolia. The essential oil was obtained by hydrodistillation and analyzed by GC and GC/MS, which allowed the identification of 14 compounds, mainly oxygenated sesquiterpenes, such as (E)‐nerolidol (33.51%) and spathulenol (16.24%). The essential oil showed activity against promastigote forms of Leishmania donovani, with IC₅₀ values of 42 μg/ml. The essential oil displayed high activity in the schistosomicidal assay, since all pairs of Schistosoma mansoni adult worms were dead after incubation with the essential oil (10, 50, and 100 μg/ml). B. dracunculifolia essential oil was neither cytotoxic against Vero cells, nor active in the antimicrobial and antiplasmodial assays.     

Prolonged survival of allografts induced by mycobacterial Hsp70 is dependent on CD4+CD25+ regulatory T cells

Background

Heat shock proteins (Hsps) are stress induced proteins with immunomodulatory properties. The Hsp70 of Mycobacterium tuberculosis (TBHsp70) has been shown to have an anti-inflammatory role on rodent autoimmune arthritis models, and the protective effects were demonstrated to be dependent on interleukin-10 (IL-10). We have previously observed that TBHsp70 inhibited maturation of dendritic cells (DCs) and induced IL-10 production by these cells, as well as in synovial fluid cells.

Methodology/Principal Findings

We investigated if TBHsp70 could inhibit allograft rejection in two murine allograft systems, a transplanted allogeneic melanoma and a regular skin allograft. In both systems, treatment with TBHsp70 significantly inhibited rejection of the graft, and correlated with regulatory T cells (Tregs) recruitment. This effect was not tumor mediated because injection of TBHsp70 in tumor-free mice induced an increase of Tregs in the draining lymph nodes as well as inhibition of proliferation of lymph node T cells and an increase in IL-10 production. Finally, TBHsp70 inhibited skin allograft acute rejection, and depletion of Tregs using a monoclonal antibody completely abolished this effect.

Conclusions/Significance

We present the first evidence for an immunosuppressive role for this protein in a graft rejection system, using an innovative approach – immersion of the graft tissue in TBHsp70 solution instead of protein injection. Also, this is the first study that demonstrates dependence on Treg cells for the immunosuppressive role of TBHsp70. This finding is relevant for the elucidation of the immunomodulatory mechanism of TBHsp70. We propose that this protein can be used not only for chronic inflammatory diseases, but is also useful for organ transplantation management.     

Transferability of short tandem repeat markers for two wild Canid species inhabiting the Brazilian Cerrado

The maned wolf (Chrysocyon brachyurus) and the crab-eating fox (Cerdocyon thous) are two wild-canid species found in the Brazilian Cerrado. We tested cross-amplification and transferability of 29 short tandem repeat primers originally developed for cattle and domestic dogs and cats on 38 individuals of each of these two species, collected in the Emas National Park, which is the largest national park in the Cerrado region. Six of these primers were successfully transferred (CSSM-038, PEZ-05, PEZ-12, LOCO-13, LOCO-15, and PEZ-20); five of which were found to be polymorphic. Genetic parameter values (number of alleles per locus, observed and expected heterozygosities, and fixation indices) were within the expected range reported for canid populations worldwide.     

Screening anion-exchange chromatographic matrices for isolation of onco-retroviral vectors

The adsorption kinetics of retroviral vectors to several chromatographic media, DEAE FF, Streamlinetrade mark Q XL and CHTtrade mark Ceramic Hydroxyapatite, in batch mode was investigated. The effects of buffer type, pH and operational temperature were studied. A mathematical model describing viral adsorption kinetics that considers viral degradation in solution was developed. The best results, either in terms of speed and extent of adsorbed infectious particles, were obtained with DEAE FF and Streamlinetrade mark Q XL. Fixed-bed chromatography was further investigated using DEAE FF, Q XL and Q FF, for validation of the batch adsorption process. Fixed-bed DEAE FF and Q XL proved to be good candidates for purification of MoMLV derived vectors due to resulting high yields, 53+/-13% and 51+/-7%, respectively, while removing more than 99% of protein and 90% of the DNA contaminants.     

Bio3d: an R package for the comparative analysis of protein structures

An automated procedure for the analysis of homologous protein structures has been developed. The method facilitates the characterization of internal conformational differences and inter-conformer relationships and provides a framework for the analysis of protein structural evolution. The method is implemented in bio3d, an R package for the exploratory analysis of structure and sequence data. AVAILABILITY: The bio3d package is distributed with full source code as a platform-independent R package under a GPL2 license from: http://mccammon.ucsd.edu/~bgrant/bio3d/