The distribution of mannose-6-phosphate receptors changes from newborns to adults in rat liver

The co-existence of two types of mannose-6-phosphate receptors (CD-MPR and CI-MPR) in most cell types is still not well explained. Some evidence suggests that the CI-MPR could be actively involved in the regulation of growth factors in the early stages of mammalian organ development. In this study, it was demonstrated that both receptors are distributed in a non-overlapping fashion in rat liver, and that the distribution of CI-MPR changes over a percoll gradient between newborn and adult animals. By using marker proteins it was observed that in newborns the CI-MPR is located both in intracellular fractions and in fractions that coincide with a plasma membrane marker, whereas in adults it is only detected in intracellular fractions. It was also noted that N-acetyl-β-d-glucosaminidase distribution is closer to CI-MPR than to CD-MPR and that acid phosphatase did not match with any receptor. This evidence may also suggest that both receptors have different functions, mainly at early stages in the development of organs.     

Cold storage of <Emphasis Type="Italic">Trichogramma nerudai</Emphasis> using an acclimation period

The availability of suitable storage methods for parasitoids is a valuable tool in biological control programs. Studies were conducted to investigate the effects of cold storage with acclimation period on the quality of Trichogramma nerudai Pintureau and Gerding. Prepupae were stored 50, 75 and 100 days at 5 °C with a previous acclimation period of 10 or 20 days at 12 °C. It was possible to arrest the development of T. nerudai. All the treatments with acclimation period of ten days had emergence values under 10% that were not useful to establish a cold storage protocol. Twenty days of acclimation had a positive impact on cold storage tolerance at 50 and 75 days. The adult emergence, the emergence time, the sex ratio, the parasitism and the progeny quality have not been affected by the storage of T. nerudai using an acclimation period of 20 days and until 50 days under cold temperature.     

The polypeptides COX2A and COX2B are essential components of the mitochondrial cytochrome c oxidase of Toxoplasma gondii

Two genes encoding cytochrome c oxidase subunits, Cox2a and Cox2b, are present in the nuclear genomes of apicomplexan parasites and show sequence similarity to corresponding genes in chlorophycean algae. We explored the presence of COX2A and COX2B subunits in the cytochrome c oxidase of Toxoplasma gondii. Antibodies were raised against a synthetic peptide containing a 14-residue fragment of the COX2A polypeptide and against a hexa-histidine-tagged recombinant COX2B protein. Two distinct immunochemical stainings localized the COX2A and COX2B proteins in the parasite's mitochondria. A mitochondria-enriched fraction exhibited cyanide-sensitive oxygen uptake in the presence of succinate. T. gondii mitochondria were solubilized and subjected to Blue Native Electrophoresis followed by second dimension electrophoresis. Selected protein spots from the 2D gels were subjected to mass spectrometry analysis and polypeptides of mitochondrial complexes III, IV and V were identified. Subunits COX2A and COX2B were detected immunochemically and found to co-migrate with complex IV; therefore, they are subunits of the parasite's cytochrome c oxidase. The apparent molecular mass of the T. gondii mature COX2A subunit differs from that of the chlorophycean alga Polytomella sp. The data suggest that during its biogenesis, the mitochondrial targeting sequence of the apicomplexan COX2A precursor protein may be processed differently than the one from its algal counterpart.     

<Emphasis Type="Italic">Steinernema costaricense</Emphasis> n. sp. and <Emphasis Type="Italic">S. puntauvense</Emphasis> n. sp. (Rhabditida: Steinernematidae), two new entomopathogenic nematodes from Costa Rica

Steinernema costaricense n. sp. and S. puntauvense n. sp. were recovered during a survey for native entomopathogenic nematodes in Costa Rica. Morphological data, molecular (28S rDNA sequence data) studies and cross-hybridisation tests were used for diagnostic and identification purposes. Additionally, 28S rDNA sequence data were used to assess the evolutionary relationships of the new species with other Steinernema spp. Morphological diagnostic features for S. costaricense n. sp. include: the body size of the infective juvenile (av. 1,696); the presence of protruding 'horn-like' cephalic papillae; the position of the excretory pore in the infective juvenile (av. 77 microm) and the first generation male (av. 117 microm); the D% value of the infective juvenile (av. 53) and the first generation male (av. 56); the E% value of the infective juvenile (av. 85); and the morphology of the spicules and gubernaculum of the first generation male. Diagnostic traits for S. puntauvense n. sp. are: the position of the excretory pore in the infective juveniles (av. 25 microm); the shape and size of the spicules and gubernaculum of the first generation male; and the shape of the tail of the first generation female. In addition to these traits, 28S rDNA sequences analysis and hybridisation tests showed that both new Steinernema species are distinct and unique entities.     

Evolutionary history of the synbranchid eels (Teleostei: Synbranchidae) in Central America and the Caribbean islands inferred from their molecular phylogeny

Swamp eels of the genera Synbranchus and Ophisternon are secondary freshwater fishes whose biogeography provides evidence of their long residence in Mesoamerica, while their impoverished species-level taxonomy might suggest a more recent diversification or a conservative morphology. We have inferred the phylogenetic relationships of Synbranchus marmoratus and Ophisternon aenigmaticum from 45 drainages throughout South, Central America, and Cuba based on mitochondrial genes (cytochrome b and ATPase 8/6). Phylogeographic analysis supported the monophyly of Mesoamerican O. aenigmaticum although our results suggest that S. marmoratus is not a monophyletic group. We found a evolutionary differentiated Synbranchus mtDNA lineage inhabiting Las Perlas islands (Pacific Panama) that appeared to be taxonomically distinct and separated for a long period of time from the main Synbranchus clade. Major synbranchid clades were also corroborated with the nuclear RAG-1 gene (1171-bp). Application of two fish-based mtDNA clocks (1.05-1.3% pairwise divergence/million year (Ma)), is in accordance with the Gondwanian origin suggested for the Synbranchidae. The mtDNA lineages exhibited a remarkable geographic structure in Central America suggesting that vicariance has most likely promoted the Synbranchus and Ophisternon mtDNA diversification. Although our data indicate the importance of the Pacific area in Synbranchus differentiation, the mtDNA divergence between South and Central American Synbranchus is too small to support Cretaceous colonization via the proto-Antillean bridge suggested by Rosen [Syst. Zool. 24 (1976) 431]. Instead, our phylogeographic results suggest that Ophisternon and Synbranchus mtDNA clades most likely colonized Central America during the Miocene (12.7-23Ma) prior the final closure of the Isthmus of Panama (3.3Ma).     

Serum Resistin and Glomerular Filtration Rate in Patients with Type 2 Diabetes

BackgroundHigh serum levels of the pro-inflammatory adipokine resistin have been associated with decreased renal function in the general population. The goal of this study was to investigate whether such association is also present among diabetic subjects, who are at increased risk of renal function loss.MethodsThe cross-sectional association between serum resistin levels and estimated glomerular filtration rate (eGFR) was investigated in 1,560 type 2 diabetic (T2D) patients of European ancestry comprised in two different cohorts: 762 patients from San Giovanni Rotondo (SGR; Italy) and 798 patients from Boston (US).ResultsSerum resistin was inversely associated with eGFR in SGR [β (SE) for one SD of resistin increment = -1.01 (0.70) ml/min/1.73m², p = 0.019] and in Boston [β (SE) = -5.31 (0.74) ml/min/1.73m², p < 0.001] samples, as well as in the two studies combined [β (SE) = -3.42 (0.52) ml/min/1.73m², p < 0.001]. The association was unaffected by adjustment for smoking habits, BMI, waist circumference, diabetes duration, HbA1c, insulin treatment, hypertension and lipid-lowering therapy: β (SE) for one SD of resistin increment = -1.07 (0.70), p = 0.02; -5.50 (0.88), p < 0.001; and -2.81 (0.55) ml/min/1.73m², p < .001, in SGR, Boston and the two studies combined, respectively. The association was significantly stronger in men than in women (p for resistin-by-gender interaction = 0.003). For each resistin SD increment, the odds of having eGFR < 0 ml/min/1.73m² increased by 22% (OR = 1.22; 95% CI 1.02–1.44; p = 0.025) in SGR sample, 69% (OR = 1.69; 95% CI 1.38–2.07; p < 0.001) in Boston sample, and 47% (OR = 1.47; 95% CI 1.29–1.68; p < 0.001) in the two studies considered together. Similar associations were observed in the adjusted model: OR 95% CI for each SD resistin increment being 1.23 (1.03–1.46), p = 0.021; 1.52 (1.20–1.92), p < 0.001; 1.33 (1.16–1.53), p < 0.001, in SGR, Boston and the two studies combined, respectively.ConclusionsThis is the first report of an association between high serum resistin and low eGFR in patients with T2D of European ancestry.     

The Interaction of Classical Complement Component C1 with Parasite and Host Calreticulin Mediates Trypanosoma cruzi Infection of Human Placenta

Background

9 million people are infected with Trypanosoma cruzi in Latin America, plus more than 300,000 in the United States, Canada, Europe, Australia, and Japan. Approximately 30% of infected individuals develop circulatory or digestive pathology. While in underdeveloped countries transmission is mainly through hematophagous arthropods, transplacental infection prevails in developed ones.

Methodology/Principal Findings

During infection, T. cruzi calreticulin (TcCRT) translocates from the endoplasmic reticulum to the area of flagellum emergence. There, TcCRT acts as virulence factor since it binds maternal classical complement component C1q that recognizes human calreticulin (HuCRT) in placenta, with increased parasite infectivity. As measured ex vivo by quantitative PCR in human placenta chorionic villi explants (HPCVE) (the closest available correlate of human congenital T. cruzi infection), C1q mediated up to a 3–5-fold increase in parasite load. Because anti-TcCRT and anti-HuCRT F(ab′)₂ antibody fragments are devoid of their Fc-dependent capacity to recruit C1q, they reverted the C1q-mediated increase in parasite load by respectively preventing its interaction with cell-bound CRTs from both parasite and HPCVE origins. The use of competing fluid-phase recombinant HuCRT and F(ab′)₂ antibody fragments anti-TcCRT corroborated this. These results are consistent with a high expression of fetal CRT on placental free chorionic villi. Increased C1q-mediated infection is paralleled by placental tissue damage, as evidenced by histopathology, a damage that is ameliorated by anti-TcCRT F(ab′)₂ antibody fragments or fluid-phase HuCRT.

Conclusions/Significance

T. cruzi infection of HPCVE is importantly mediated by human and parasite CRTs and C1q. Most likely, C1q bridges CRT on the parasite surface with its receptor orthologue on human placental cells, thus facilitating the first encounter between the parasite and the fetal derived placental tissue. The results presented here have several potential translational medicine aspects, specifically related with the capacity of antibody fragments to inhibit the C1q/CRT interactions and thus T. cruzi infectivity.     

Beyond Reserves: A Research Agenda for Conserving Biodiversity in Human-modified Tropical Landscapes

To truly understand the current status of tropical diversity and to forecast future trends, we need to increase emphasis on the study of biodiversity in rural landscapes that are actively managed or modified by people. We present an integrated landscape approach to promote research in human-modified landscapes that includes the effects of landscape structure and dynamics on conservation of biodiversity, provision of ecosystem services, and sustainability of rural livelihoods. We propose research priorities encompassing three major areas: biodiversity, human–environment interactions, and restoration ecology. We highlight key areas where we lack knowledge and where additional understanding is most urgent for promoting conservation and sustaining rural livelihoods. Finally, we recommend participatory and multidisciplinary approaches in research and management. Lasting conservation efforts demand new alliances among conservation biologists, agroecologists, agronomists, farmers, indigenous peoples, rural social movements, foresters, social scientists, and land managers to collaborate in research, co-design conservation programs and policies, and manage human-modified landscapes in ways that enhance biodiversity conservation and promote sustainable livelihoods.     

Discovery of A-type procyanidin dimers in yellow raspberries by untargeted metabolomics and correlation based data analysis

Introduction

Raspberries are becoming increasingly popular due to their reported health beneficial properties. Despite the presence of only trace amounts of anthocyanins, yellow varieties seems to show similar or better effects in comparison to conventional raspberries.

Objectives

The aim of this work is to characterize the metabolic differences between red and yellow berries, focussing on the compounds showing a higher concentration in yellow varieties.

Methods

The metabolomic profile of 13 red and 12 yellow raspberries (of different varieties, locations and collection dates) was determined by UPLC–TOF-MS. A novel approach based on Pearson correlation on the extracted ion chromatograms was implemented to extract the pseudospectra of the most relevant biomarkers from high energy LC–MS runs. The raw data will be made publicly available on MetaboLights (MTBLS333).

Results

Among the metabolites showing higher concentration in yellow raspberries it was possible to identify a series of compounds showing a pseudospectrum similar to that of A-type procyanidin polymers. The annotation of this group of compounds was confirmed by specific MS/MS experiments and performing standard injections.

Conclusions

In berries lacking anthocyanins the polyphenol metabolism might be shifted to the formation of a novel class of A-type procyanidin polymers.

     

Plant activation of aromatic amines mediated by cytochromes P450 and flavin-containing monooxygenases

To know the mechanisms involved in the activation of promutagenic aromatic amines mediated by plants, we used Persea americana S117 system (S117) for the activation of 2-aminofluorene (2-AF) and m-phenylenediamine (m-PDA) in Ames assays. In these assays, the effect of the diphenylene iodonium (DPI), an inhibitor of flavin-containing monooxygenases (FMOs), of the 1-aminobenzotriazole (1-ABT), an inhibitor of cytochromes P450 (cyt-P450s) and of the methimazole, a high-affinity substrate for FMOs, was studied. The efficacy of both inhibitors and of the methimazole was verified to find that they did partially inhibit the mutagenesis of both aromatic amines, activated with rat liver S9. Similarly, both inhibitors and methimazole did produce a significant decrease in 2-AF and m-PDA mutagenesis, when the activation system was S117, indicating that, similar to what occurs in mammalian systems, plant FMOs and cyt-P450s can metabolize aromatic amines to mutagenic product(s). However, the affinity of both FMOs and cyt-P450s of plant for 2-AF and m-PDA was different. Data obtained indicate that the activities of plant FMOs must be the main enzymatic system of m-PDA activation while, in 2-AF activation, plant cyt-P450s have the most relevant activities. In addition, peroxidases of the S117 system must contribute to 2-AF activation and some isoforms of FMOs and/or cyt-P450s of the S117 system, uninhibited by the inhibitors used, must be the responsible for a partial activation of m-PDA.