Trypanosoma cruzi disrupts myofibrillar organization and intracellular calcium levels in mouse neonatal cardiomyocytes

Immunofluorescence studies of normal and Trypanosoma cruzi-infected primary cultures of heart muscle cells were performed to gather information about the arrangement of myofibrillar components during the intracellular life cycle of this parasite. By using a panel of monoclonal antibodies against various myofibrillar proteins, a progressive disruption and loss of contractile proteins (such myosin and actin) of the host cell was detected during infection. The host cell formed a loose network of myofibrillar proteins around the parasites. Breakdown of the myofibrils occurred in regions where the parasites were present, and heavily infected cells showed myofibrillar proteins at their periphery. In parallel, we investigated the effect of T. cruzi infection on intracellular calcium levels by using a Ca²⁺ fluorescent indicator (confocal microscopy). Infected cardiomyocytes displayed a marked impairment in contractility, and calcium influxes became irregular and less intense when compared with those of non-infected cells. Our results demonstrate that T. cruzi infection dramatically affects calcium fluxes and causes myofibrillar breakdown disturbing cardiomyocyte contractility.Financial support through grants and scholarships from the Brazilian funding agencies FAPESP, CNPq, and CAPES is gratefully acknowledged.     

The role of very small fragments in conserving genetic diversity of a common tree in a hyper fragmented Brazilian Atlantic forest landscape

In hyper fragmented biomes, conservation of extant biota relies on preservation and proper management of remnants. The maintenance of genetic diversity and functional connectivity in a landscape context is probably key to long-term conservation of remnant populations. We measured the genetic diversity in seedlings and adults of tree Copaifera langsdorffii and evaluated whether edge and density-dependent effects drive natural regeneration in a set of very small and degraded Brazilian Atlantic forest fragments. We evaluated the role of small remnants in the conservation of genetic diversity in a hyper fragmented landscape and discuss the challenge of long-term population sustainability of such altered habitats. High genetic diversity in adults indicated these fragments are valuable targets for C. langsdorffii in situ conservation, but both genetic diversity and divergence among patches decreased in seedlings. In our landscape, regeneration increased as it neared edges and adults; suggesting this population is resilient to fragmentation. However, at a broader scale, current levels of gene flow have not been sufficient to prevent the loss of genetic diversity across generations. Restoration plans, even at a small scale, are necessary to promote fragment connectivity and spatially expand opportunities for the fairly restricted gene flow observed in this severely fragmented Brazilian Atlantic forest region.     

Carbon-13 labelling strategy for studying the ATP metabolism in individual yeast cells by micro-arrays for mass spectrometry

Isotopic labelling of cellular metabolites, used in conjunction with high-density micro-arrays for mass spectrometry enables observation of ATP metabolism in single yeast cells.     

Adenovirus-5-vectored P. falciparum vaccine expressing CSP and AMA1. Part B: safety, immunogenicity and protective efficacy of the CSP component

Background

A protective malaria vaccine will likely need to elicit both cell-mediated and antibody responses. As adenovirus vaccine vectors induce both these responses in humans, a Phase 1/2a clinical trial was conducted to evaluate the efficacy of an adenovirus serotype 5-vectored malaria vaccine against sporozoite challenge.

Methodology/Principal Findings

NMRC-MV-Ad-PfC is an adenovirus vector encoding the Plasmodium falciparum 3D7 circumsporozoite protein (CSP). It is one component of a two-component vaccine NMRC-M3V-Ad-PfCA consisting of one adenovector encoding CSP and one encoding apical membrane antigen-1 (AMA1) that was evaluated for safety and immunogenicity in an earlier study (see companion paper, Sedegah et al). Fourteen Ad5 seropositive or negative adults received two doses of NMRC-MV-Ad-PfC sixteen weeks apart, at particle units per dose. The vaccine was safe and well tolerated. All volunteers developed positive ELISpot responses by 28 days after the first immunization (geometric mean 272 spot forming cells/million[sfc/m]) that declined during the following 16 weeks and increased after the second dose to levels that in most cases were less than the initial peak (geometric mean 119 sfc/m). CD8+ predominated over CD4+ responses, as in the first clinical trial. Antibody responses were poor and like ELISpot responses increased after the second immunization but did not exceed the initial peak. Pre-existing neutralizing antibodies (NAb) to Ad5 did not affect the immunogenicity of the first dose, but the fold increase in NAb induced by the first dose was significantly associated with poorer antibody responses after the second dose, while ELISpot responses remained unaffected. When challenged by the bite of P. falciparum-infected mosquitoes, two of 11 volunteers showed a delay in the time to patency compared to infectivity controls, but no volunteers were sterilely protected.

Significance

The NMRC-MV-Ad-PfC vaccine expressing CSP was safe and well tolerated given as two doses, but did not provide sterile protection.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00392015","term_id":"NCT00392015"}}NCT00392015     

Genetic evaluation of the mating system in the blue-and-yellow macaw (Ara ararauna, Aves, Psittacidae) by DNA fingerprinting

More than 90% of birds are socially monogamous, although genetic studies indicate that many are often not sexually monogamous. In the present study, DNA fingerprinting was used to estimate the genetic relationships between nestlings belonging to the same broods to evaluate the mating system in the socially monogamous macaw, Ara ararauna. We found that in 10 of 11 broods investigated, the nestlings showed genetic similarity levels congruent with values expected among full-sibs, suggesting that they shared the same parents. However, in one brood, the low genetic similarity observed between nestlings could be a result of intraspecific brood parasitism, intraspecific nest competition or extra-pair paternity. These results, along with available behavioral and life-history data, imply that the blue-and-yellow macaw is not only socially, but also genetically monogamous. However, the occurrence of eventual cases of extra-pair paternity cannot be excluded.     

A biomechanical analysis on the impact of episiotomy during childbirth

Episiotomy is still a controversy issue among physicians, despite the enormous growth of clinical research. Therefore, the potential of numerical modeling of anatomical structures to simulate biomechanical processes was exploited to realize quantitatively the real effects of the episiotomy and its consequences on the pelvic floor muscle. As such, a numerical model was used composed of pelvic floor muscles, a surface delimiting the anterior region, and a fetus body. A normal vaginal delivery without and with different episiotomies was simulated with the fetus in vertex presentation and occipitoanterior position. According to our numerical results, a mediolateral episiotomy has a protective effect, reducing the stress on the muscles, and the force required to delivery successfully up to 52.2 %. The intervention also has benefits on muscle injury, reducing the damage to a small zone. This study demonstrates the feasibility of using a computational modeling approach to study parturition, namely the capability to isolate and evaluate the mechanical significance of a single feature. It must, however, be taken into account that the numerical model does not assess problems that may occur as blood loss, infections and others, so it is necessary to examine whether the benefits of an intervention outweigh the risks.     

Optimization of arsenic phytoremediation using Eichhornia crassipes

This study aimed to evaluate the pH, phosphate, and nitrate in the process of arsenic absorption by Eichhornia crassipes (water hyacinth), using the surface response methodology, in order to optimize the process. The plants were exposed to a concentration of arsenic of 0.5 mg L^?1 (NaAsO₂) over a period of 10 days. The results indicated optimal levels for the absorption of arsenic by E. crassipes at pH equal to 7.5, absence of phosphate, and minimum nitrate level of 0.0887 mmol L^?1. For the tested concentration, E. crassipes was able to accumulate 498.4 mg kg^?1 of As (dry base) in its plant tissue and to reduce 83% of the initial concentration present in the aqueous medium where it was cultivated. The concentration of phosphorus in solution linearly increased the phosphorus content in the plants and negatively influenced the absorption of arsenic. The concentration of 0.5 mg L^?1 of As did not significantly affect the relative growth rate (RGR) and the tolerance index (TI). 94% of As (III) initially solubilized in water was converted by the end of the experiment period into As (V). The water hyacinth was important in the phytoremediation of arsenic when cultivated under optimal conditions for its removal.     

In vitro efficacy of <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> sensu lato against unfed <Emphasis Type="Italic">Amblyomma parvum</Emphasis> (Acari: Ixodidae)

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum.     

Mire vegetation in the Apuanian Alps (Italy)

Mire vegetation in the Apuanian Alps (N Italy) is analyzed from the phytosociological and the synecological points of view. Three vegetation types are delimited by numerical methods and compared with mire communities of the Alps and the Apennines. Furthermore, a chorological evaluation of this vegetation is attempted on a floristical basis.     

Giant kelp (Macrocystis) fishery in Atacama (Northern Chile): biological basis for management of the integrifolia morph

In Bahia Chasco, Atacama, the integrifolia morph of Macrocystis forms one of the most important kelp forests in northern Chile. In order to determine effects of local harvesting policies, we evaluated the population dynamics of this resource in intact, frequently disturbed, and permanently and completely harvested areas. Recruitment, frond length, reproductive phenology and standing crop were assessed monthly. In intact areas, frond length and ratio of reproductive individuals were higher, but recruitment was poorly stimulated. On the other hand, complete harvest had an important effect on Macrocystis population dynamics. Whereas recruitment and growth were much higher after harvest events, reproductive phenology was lower. The harvest techniques with different frequencies practiced by Bahia Chasco fishermen were less harmful than complete harvest, and we conclude that current exploitation techniques applied in this location are not deleterious for the giant kelp beds. They even have favorable effects by renewing the population through stimulation of sexual reproduction, recruitment and growth of young individuals.