Methyl jasmonate changes the levels of rubisco and other leaf proteins in Ricinus communis

The effect of methyl jasmonate (MJ) on the water-soluble protein pattern of Ricinus communis leaves was analyzed. Several dynamic changes occurred after a period of 24 and 48h including six proteins (M_r 13,000, 15,000, 16,000, 27,000, 29,000 and 60,000) whose levels increased by 48h and seven others (M_r 11,000, 18,000, 20,000 30,000, 37,000, 40,000 and 58,000) whose levels decreased. Four proteins (M_r 24,000, 34,000, 64,000 and 66,000) were induced after 24h of treatment, but returned to control levels by 48h. On the other hand, the levels of three proteins (M_r 74,000, 84,000 and 88,000) decreased after 24h, but returned to control levels after 48h. One of the proteins that accumulated after 48 h had the 13 first residues sequenced. This polypeptide named MJRC-15, was identical to the C-terminal sequence of Rubisco-large chain polypeptide (position 337–350) from tobacco chloroplast. Western-blot analysis using polyclonal antibodies against Rubisco supports the hypothesis that MJRC-15 is a degradation product of Rubisco.     

Seasonality rather than average temperature explains body size variation in a Neotropical fruit-eating bat

We investigated variation in body size of the widely distributed Neotropical bat Chiroderma villosum across its entire range. Our objective was to verify if the size-related geographic variation in the species is related to environmental variables. We took 13 measurements of 410 specimens from 198 localities in Mesoamerica and South America, and collected information on latitude, longitude, altitude, precipitation, and temperature, totalling 22 variables. We detected clinal variation in size related to latitude and longitude, with a pattern that conforms to the Bergmann's rule. Clinal variation of size along longitude was influenced by the taxonomic component, with subspecies C. v. jesupi being smaller than C. v. villosum. In contrast the latitudinal cline was explained by temperature seasonality and precipitation, with a 14% increase in size between the north and south extremes of the range. In other words, size of individuals is larger in areas with more seasonal oscillations in temperature and with lower precipitation. Our results support the notion that low temperatures alone do not explain large size of mammals in high latitudes. One hypothesis is that large size is favoured in more seasonal climates because somatic growth is faster when resources are abundant, and also larger animals can endure food scarcity better than small ones. We also postulate that pressures related to interspecific competition and resource use may be more intense in more areas marked by seasonal climatic variations. Specifically, a larger size in seasonal areas may allow individuals to explore a wider niche. We suggest that future approaches, refining regional variation in the diet of C. villosum may serve as a further test to this hypothesis.     

Immune response dynamics and Lutzomyia longipalpis exposure characterize a biosignature of visceral leishmaniasis susceptibility in a canine cohort

BackgroundReports have shown correlations between the immune response to vector saliva and Leishmaniasis outcome. We followed dogs in an endemic area for two years characterizing resistance or susceptibility to canine visceral leishmaniasis (CVL) according to Leishmania infantum diagnosis and clinical development criteria. Then, we aimed to identify a biosignature based on parasite load, serum biological mediators’ interactions, and vector exposure intensity associated with CVL resistance and susceptibility.Methodology/Principal findingsA prospective two-year study was conducted in an area endemic for CVL. Dogs were evaluated at 6-month intervals to determine infection, clinical manifestations, immune profile, and sandfly exposure. CVL resistance or susceptibility was determined upon the conclusion of the study. After two years, 78% of the dogs were infected with L. infantum (53% susceptible and 47% resistant to CVL). Susceptible dogs presented higher splenic parasite load as well as persistence of the parasite during the follow-up, compared to resistant ones. Susceptible dogs also displayed a higher number of correlations among the investigated biological mediators, before and after infection diagnosis. At baseline, anti-saliva antibodies, indicative of exposure to the vector, were detected in 62% of the dogs, reaching 100% in one year. Higher sandfly exposure increased the risk of susceptibility to CVL by 1.6 times (CI: 1.11–2.41). We identified a discriminatory biosignature between the resistant and susceptible dogs assessing splenic parasite load, interaction of biological mediators, PGE₂ serum levels and intensity of exposure to sandfly. All these parameters were elevated in susceptible dogs compared to resistant animals.Conclusions/SignificanceThe biosignature identified in our study reinforces the idea that CVL is a complex multifactorial disease that is affected by a set of factors which are correlated and, for a better understanding of CVL, should not be evaluated in an isolated way.     

Neutralization of macrophage inflammatory protein-2 blocks the febrile response induced by lipopolysaccharide in rats

1. This study was aimed to test the hypothesis that macrophage inflammatory protein-2 (MIP-2), a powerful chemotactic cytokine for neutrophils, plays a role in bacterial endotoxin fever.

2. The effect of specific anti-rat MIP-2 antibodies on lipopolysaccharide (LPS)-induced fever was tested. Intraperitoneal injection of LPS resulted in a biphasic fever and a significant increase in serum MIP-2 and prostaglandin (PG) E₂ levels which correlated with the start of fever. Intraperitoneal anti-MIP-2 (500 μg/kg) did not affect the body core temperature of unrestrained rats, but markedly attenuated LPS-induced fever.

3. Treatment with the cyclooxygenase inhibitor ibuprofen (10 mg/kg) resulted in a significant attenuation of LPS-induced fever and a significant decrease of MIP-2 and PGE₂ production.

4. These results indicate that LPS fever in rats is, at least, in part dependent on mechanisms involving neutrophils chemotaxis, and that MIP-2 may be an important mediator in the genesis of fever via prostaglandin-dependent pathways.     

Decreased serum interleukin 27 in Brazilian systemic lupus erythematosus patients

The immunological role of interleukin 27 has been reported in various inflammatory diseases, but its importance in systemic lupus erythematosus pathogenesis is not completely established. The aim of this study was to evaluate serum levels of IL-27 in SLE patients and its correlation with clinical manifestations and disease activity. IL-27 levels were assessed in 70 SLE patients and 30 healthy controls by ELISA. Clinical and laboratory parameters were recorded. Statistic analyzes were performed by Graph Prism 3.02 software. The IL-27 serum levels were significantly decreased in SLE patients compared with controls (mean 899.92 and 1,531.22 pg/ml, P = 0.0005). There was a correlation between IL-27 levels and C3 levels (P = 0.004). Nevertheless, there was no association of serum IL-27 levels with disease activity evaluated by SLEDAI score (P = 0.9605). No significant difference was found regarding IL-27 levels between SLE patients with and without nephritis, haematuria, proteinuria and positive anti-dsDNA. Correlation analysis between serum IL-27 levels and SLEDAI, SLICC, proteinuria levels, C4 and CH50 levels also showed no association. These data demonstrated decreased serum levels of IL-27 in SLE patients but further studies are needed to clarify the precise role of this cytokine and its potential use as therapeutic target.     

Reevaluation of Production of Paralytic Shellfish Toxin by Bacteria Associated with Dinoflagellates of the Portuguese Coast

Paralytic shellfish toxins (PSTs) are potent neurotoxins produced by certain dinoflagellate and cyanobacterial species. The autonomous production of PSTs by bacteria remains controversial. In this study, PST production by two bacterial strains, isolated previously from toxic dinoflagellates, was evaluated using biological and analytical methods. Analyses were performed under conditions determined previously to be optimal for toxin production and detection. Our data are inconsistent with autonomous bacterial PST production under these conditions, thereby challenging previous findings for the same strains.     

Coffee beverage preparation by different methods from an environmental perspective

The International Journal of Life Cycle Assessment - Coffee is among the most appreciated beverages in the world, and there is a wide variety of methods of coffee consumption, inside and outside...