Decreased secretion of MMP by non-lesional late-stage scleroderma fibroblasts after selection via activation of the apoptotic Fas-pathway

Our hypothesis is that the development of lesional areas of skin in patients with systemic sclerosis (SSc) originates from the selection of profibrotic cell subpopulations within their non-lesional skin areas, due to their greater resistance to apoptosis. Sensitivity to apoptosis of early-stage or late-stage SSc fibroblasts as well as of healthy cells was compared using extrinsic or intrinsic apoptotic pathway-inducers. Subpopulations of non-lesional SSc cells and healthy cells obtained after repeated Fas-induced apoptosis were compared with respect to their fibrotic parameters such as collagen and MMP secretion. Only late-stage lesional SSc cells were more resistant to Fas-induced apoptosis than their non-lesional counterparts isolated from the same patient. This result correlated with an increase in the levels of the anti-apoptotic proteins cFLIPs and cIAP in lesional cells compared to non-lesional cells. Healthy and non-lesional cell populations could be selected to generate a subpopulation that was more resistant to apoptosis. However, only the late-stage non-lesional SSc fibroblast populations showed a significant decrease in MMP secretion, one of parameters of the fibrosis. Our results show that resistance to apoptosis is an important characteristic of the late-stage lesional SSc fibroblast phenotype. We thus hypothesized that a selection of specific fibroblast subpopulations from late-stage non-lesional SSc skin areas could be at the origin of lesional populations. These cells should become independent of any exogenous stimuli and can induce or maintain SSc skin lesions.     

Ziehl-Neelsen staining technique can diagnose paragonimiasis

Background

We evaluated the Ziehl-Neelsen staining (ZNS) technique for the diagnosis of paragonimiasis in Laos and compared different modifications of the ZNS techniques.

Methodology

We applied the following approach: We (1) examined a paragonimiasis index case''s sputum with wet film direct examination (WF) and ZNS; (2) re-examined stored ZNS slides from two provinces; (3) compared prospectively WF, ZNS, and formalin-ether concentration technique (FECT) for sputum examination of patients with chronic cough; and (4) compared different ZNS procedures. Finally, we assessed excess direct costs associated with the use of different diagnostic techniques.

Principal Findings

Paragonimus eggs were clearly visible in WF and ZNS sputum samples of the index case. They appeared brownish-reddish in ZNS and were detected in 6 of 263 archived ZNS slides corresponding to 5 patients. One hundred sputum samples from 43 patients were examined with three techniques, which revealed that 6 patients had paragonimiasis (13 positive samples). Sensitivity per slide of the FECT, ZNS and the WF technique was 84.6 (p = 0.48), 76.9 (p = 0.25) and 61.5% (p = 0.07), respectively. Percentage of fragmented eggs was below 19% and did not differ between techniques (p = 0.13). Additional operational costs per slide were 0 (ZNS), 0.10 US$ (WF), and 0.79 US$ (FECT). ZNS heated for five minutes contained less eggs than briefly heated slides (29 eggs per slide [eps] vs. 42 eps, p = 0.01). Bloodstained sputum portions contained more eggs than unstained parts (3.3 eps vs. 0.7 eps, p = 0.016).

Conclusions/Significance

Paragonimus eggs can easily be detected in today''s widely used ZNS of sputum slides. The ZNS technique appears superior to the standard WF sputum examination for paragonimiasis and eliminates the risk of tuberculosis transmission. Our findings suggest that ZNS sputum slides should also be examined routinely for Paragonimus eggs. ZNS technique has potential in epidemiological research on paragonimiasis.     

Putting into practice domain-linear motif interaction predictions for exploration of protein networks

PDZ domains recognise short sequence motifs at the extreme C-termini of proteins. A model based on microarray data has been recently published for predicting the binding preferences of PDZ domains to five residue long C-terminal sequences. Here we investigated the potential of this predictor for discovering novel protein interactions that involve PDZ domains. When tested on real negative data assembled from published literature, the predictor displayed a high false positive rate (FPR). We predicted and experimentally validated interactions between four PDZ domains derived from the human proteins MAGI1 and SCRIB and 19 peptides derived from human and viral C-termini of proteins. Measured binding intensities did not correlate with prediction scores, and the high FPR of the predictor was confirmed. Results indicate that limitations of the predictor may arise from an incomplete model definition and improper training of the model. Taking into account these limitations, we identified several novel putative interactions between PDZ domains of MAGI1 and SCRIB and the C-termini of the proteins FZD4, ARHGAP6, NET1, TANC1, GLUT7, MARCH3, MAS, ABC1, DLL1, TMEM215 and CYSLTR2. These proteins are localised to the membrane or suggested to act close to it and are often involved in G protein signalling. Furthermore, we showed that, while extension of minimal interacting domains or peptides toward tandem constructs or longer peptides never suppressed their ability to interact, the measured affinities and inferred specificity patterns often changed significantly. This suggests that if protein fragments interact, the full length proteins are also likely to interact, albeit possibly with altered affinities and specificities. Therefore, predictors dealing with protein fragments are promising tools for discovering protein interaction networks but their application to predict binding preferences within networks may be limited.     

Ground-foraging ants (Hymenoptera: Formicidae) and rainfall effect on pitfall trapping in a deciduous thorn woodland (caatinga), Northeastern Brazil

The semi-arid Caatinga is the fourth largest biome of Brazil, which biota still remains one of the most poorly known, especially with regard to invertebrate groups. In this study, a ground-foraging ant assemblage was surveyed during one year and the effect of rainfall on pitfall trapping was assessed. The study was performed in an area located in the municipality of Pentecoste (3 degrees 48' S - 39 degrees 20' W), in the State of Ceará. A 200m transect with 20 equidistant sampling points was established. Transect sampling was performed once a month during 12 months, over the period August 2008-August 2009. At each sampling point, a pitfall trap partially filled with a mixture of ethanol and monoethylene glycol was placed at the beginning of each month and remained in the field for seven days. 39 species belonging to six subfamilies and 19 genera, plus two unidentified species, were collected, with Pheidole (10 spp.) and Camponotus (8 spp.) being the taxa with the most species. 23 species were frequent, being found in more than 50% of the 12 transect samplings. Five species had an intermediate frequency (25 to 50%), while 13 were relatively infrequent (less than 25%). Most of the species (22) showed low occurrence, being found in less than 10% of the 240 samples (20 samples each month, during 12 months). Only five species were collected in more than 50% of the samples, those species being also responsible for most of the total abundance (number of captured individuals of all species) observed each month. The species-accumulation curves (observed and estimated) indicated that sampling sufficiency was attained, and that about 92% of the estimated ground-foraging ant fauna had been collected. 40 and 29 species were collected in the dry and rainy season, respectively, with monthly species richness ranging from 13 to 28. The total ant abundance showed a drastic decrease during the rainy season, and a negative linear correlation was found between rainfall and total ant abundance (R2 = 0.68). A similar negative linear correlation was found for species occurrences against rainfall (R2 = 0.71), and for mean number of species per pitfall trap against rainfall (R2 = 0.71). However, some species showed equal abundance, occurrence and mean number of individuals per pitfall trap in both seasons, while others showed a much higher abundance and occurrence during the rainy season. Pitfall trapping as a method to sample ground-foraging ant assemblage of the Caatinga biome and potential factors responsible for lower pitfall trap performance during rainy season are discussed.     

Community structure of insect herbivores is driven by conservatism,escalation and divergence of defensive traits in Ficus

Escalation (macroevolutionary increase) or divergence (disparity between relatives) in trait values are two frequent outcomes of the plant‐herbivore arms race. We studied the defences and caterpillars associated with 21 sympatric New Guinean figs. Herbivore generalists were concentrated on hosts with low protease and oxidative activity. The distribution of specialists correlated with phylogeny, protease and trichomes. Additionally, highly specialised Asota moths used alkaloid rich plants. The evolution of proteases was conserved, alkaloid diversity has escalated across the studied species, oxidative activity has escalated within one clade, and trichomes have diverged across the phylogeny. Herbivore specificity correlated with their response to host defences: escalating traits largely affected generalists and divergent traits specialists; but the effect of escalating traits on extreme specialists was positive. In turn, the evolution of defences in Ficus can be driven towards both escalation and divergence in individual traits, in combination providing protection against a broad spectrum of herbivores.     

Morphology,development and evolutionary significance of the working stages in the caste system of Prorhinotermes (Insecta,Isoptera)

Summary The existence of a worker caste in Prorhinotermes inopinatus was determined with the help of biometrical analyses and morphological observations. No dichotomy between alate and worker lines was detected among the young larval instars. Mandible sclerotization and wear show that the larvae become active by the fourth instar in mature colonies, and by the third in incipient ones. Prothoracic finger-shaped expansions characterize the most dependent larval instars. The antennal structure is the best feature for distinguishing late instars. The developmental schema is very flexible: the late larvae of stages 5 to 8 (at least) can give rise to wing-padded nymphs, to the next larval instar, to presoldiers, or most likely to neotenic reproductives as well; the wing-padded individuals (nymphs) normally moult direct to alates, but they can also undergo a regression of their wing pads and revert to worker-like individuals or differentiate into soldiers or neotenics. Slight variations in alate size and antennal morphology result from their origin in different larval instars. Whole-colony censuses revealed that the major part of the colony's work force is composed of pseudergates, i.e. late larvae that do not follow the most direct pathway to the alate. The pseudergates of Prohinotermes do not constitute a distinct worker caste irreversibly diverted from the alate developmental pathway. For this reason the caste system of Prorhinotermes is analogous to that of the Kalotermitidae and Termopsidae and much more primitive than those of the other Rhinotermitidae so far studied, Reticulitermes, Schedorhinotermes and Coptotermes.Contribution No. 139 from King Léopold III Biological Station, Laing Island, Papua New GuineaSenior research assistant of the National Fund for Scientific Research, Belgium     

Prevalence of the 281 (Gly→Glu) mutation in hepatoerythropoietic porphyria and porphyria cutanea tarda

Summary The prevalence of the 281 (GlyGlu) mutation in hepatoerythropoietic porphyria (HEP) was investigated by the use of hybridization with a synthetic oligonucleotide probe. The mutation was found in HEP-affected members of two unrelated families from Spain, but was absent in two other patients from Italy and Portugal who also had HEP. Moreover, this mutation was not detected in 13 unrelated cases of familial (type II) porphyria cutanea tarda.     

Partial 9q trisomy associated with a 9,21 translocation

Summary A new case of partial trisomy 9q was found in a child presenting two de novo aberrations: a deletion of the long arms of 9 and a 9,21 translocation. A tentative cytogenetic explanation is put forward.     

Identification of Bacterial Strains Isolated from the Mediterranean Sea Exhibiting Different Abilities of Biofilm Formation

The Mediterranean Sea has rarely been investigated for the characterization of marine bacteria as compared to other marine environments such as the Atlantic or Pacific Ocean. Bacteria recovered from inert surfaces are poorly studied in these environments, when it has been shown that the community structure of attached bacteria can be dissimilar from that of planktonic bacteria present in the water column. The objectives of this study were to identify and characterize marine bacteria isolated from biofilms developed on inert surfaces immersed in the Mediterranean Sea and to evaluate their capacity to form a biofilm in vitro. Here, 13 marine bacterial strains have been isolated from different supports immersed in seawater in the Bay of Toulon (France). Phylogenetic analysis and different biological and physico-chemical properties have been investigated. Among the 13 strains recovered, 8 different genera and 12 different species were identified including 2 isolates of a novel bacterial species that we named Persicivirga mediterranea and whose genus had never been isolated from the Mediterranean Sea. Shewanella sp. and Pseudoalteromonas sp. were the most preponderant genera recovered in our conditions. The phenotypical characterization revealed that one isolate belonging to the Polaribacter genus differed from all the other ones by its hydrophobic properties and poor ability to form biofilms in vitro. Identifying and characterizing species isolated from seawater including from Mediterranean ecosystems could be helpful for example, to understand some aspects of bacterial biodiversity and to further study the mechanisms of biofilm (and biofouling) development in conditions approaching those of the marine environment.