Ontogeny of the VIP system in the gastro-intestinal tract of the Axolotl,Ambystoma mexicanum: successive appearance of co-existing PACAP and NOS

Evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and nitric oxide synthase (NOS) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. This immunofluorescence study aims to clarify the appearance and localization of VIP, PACAP and NOS in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum, during ontogeny. VIP-immunoreactivity appeared in nerve fibers as early as on day 3 after hatching likely indicating a particular role, such as a trophic action, of VIP in very early development. PACAP-immunoreactivity was observed 3 days later within the VIP-immunoreactive (-IR) fibers. From this time on, VIP- and PACAP-immunoreactivity exhibited complete co-existence. VIP/PACAP-IR fibers were found throughout the gastro-intestinal tract. They were most prominent in the myenteric plexus and the muscle layers and less frequent in the submucosa. NOS-immunoreactivity appeared as late as at the 1st (64 days) juvenile stage in a subpopulation of the VIP/PACAP-IR fibers that contacted submucosal arteries. We found only very few VIP/PACAP-IR perikarya, indicating that part of the VIP/PACAP-IR fibers is of extrinsic origin. On day 12 and in the 1st and 2nd (104 days) juvenile stage, infrequent PACAP-IR entero-endocrine cells were noted, while neither VIP- nor NOS-immunoreactivity occurred in endocrine cells at any stage of development. The complete coexistence of neuronal PACAP- and VIP-immunoreactivities and their very early appearance in ontogeny may suggest important and coordinated roles of both peptides in the control of Axolotl gastro-intestinal activity, while the VIP/ PACAP/NOS-IR fibers may be involved in the regulation of submucosal blood flow.     

Cercarial shedding from <Emphasis Type="Italic">Galba</Emphasis><Emphasis Type="Italic">truncatula</Emphasis> infected with <Emphasis Type="Italic">Fasciola</Emphasis><Emphasis Type="Italic">gigantica</Emphasis> of distinct geographic origins

Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails.     

Cysteine proteinases from promastigotes of <Emphasis Type="Italic">Leishmania</Emphasis> (<Emphasis Type="Italic">Viannia</Emphasis>) <Emphasis Type="Italic">braziliensis</Emphasis>

Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of 63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection.     

Functional polymorphisms in <Emphasis Type="Italic">XRCC</Emphasis>-<Emphasis Type="Italic">1</Emphasis> and <Emphasis Type="Italic">APE</Emphasis>-<Emphasis Type="Italic">1</Emphasis> contribute to increased apoptosis and risk of ulcerative colitis

Objective  

The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC).     

Redescription of <Emphasis Type="Italic">Lemuricola</Emphasis> (<Emphasis Type="Italic">Madoxyuris</Emphasis>) <Emphasis Type="Italic">bauchoti</Emphasis> (Nematoda,Oxyuridae) from <Emphasis Type="Italic">Lemur catta</Emphasis> in Madagascar

Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini hosts will only be proven when additional records fill in the gaps in their distribution.     

Selective activity of extracts of <Emphasis Type="Italic">Margaritaria discoidea</Emphasis> and <Emphasis Type="Italic">Homalium africanum</Emphasis> on <Emphasis Type="Italic">Onchocerca ochengi</Emphasis>

Background  

The current treatment of onchocerciasis relies on the use of ivermectin which is only microfilaricidal and for which resistant parasite strains of veterinary importance are increasingly being detected. In the search for novel filaricides and alternative medicines, we investigated the selective activity of crude extracts of Margaritaria discoidea and Homalium africanum on Onchocerca ochengi, a model parasite for O. volvulus. These plants are used to treat the disease in North West Cameroon.     

<Emphasis Type="Italic">P</Emphasis>. <Emphasis Type="Italic">aeruginosa</Emphasis> Biofilms in CF Infection

Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised hosts. In cystic fibrosis (CF), P. aeruginosa causes acute and chronic lung infections that result in significant morbidity and mortality. P. aeruginosa possesses several traits that contribute to its ability to colonize and persist in acute and chronic infections. These include high resistance to antimicrobials, ability to form biofilms, plethora of virulence products, and metabolic versatility. In P. aeruginosa, a cell-to-cell communication process termed quorum sensing (QS) regulates many of these factors that contribute to its pathogenesis. Recent evidence suggests that the CF lung environment presents a specialized niche for P. aeruginosa. The relationship of P. aeruginosa QS, biofilm formation, and the CF lung environment is discussed.     

Subcellular localization of an extracellular serine protease in<Emphasis Type="Italic"> Leishmania</Emphasis> (<Emphasis Type="Italic">Leishmania</Emphasis>)<Emphasis Type="Italic"> amazonensis</Emphasis>

Extracellular proteolytic activity was detected in a Leishmania (L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH₄)₂SO₄ precipitation followed by affinity chromatography on aprotinin–agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. (L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking.     

Evaluation of the BactiCard <Emphasis Type="Italic">Neisseria</Emphasis> for Identification of Pathogenic <Emphasis Type="Italic">Neisseria</Emphasis> Species and <Emphasis Type="Italic">Moraxella catarrhalis</Emphasis>

The BactiCard Neisseria (Remel, USA) is a chromogenic enzyme substrate system for identifying Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria lactamica, and Moraxella catarrhalis. The identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl butyrate esterase (IB), prolyl aminopeptidase (PRO), γ-glutamyl aminopeptidase (GLUT), and ?-galactosidase (BGAL). These substrates permit the identification of Moraxella catarrhalis, Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica, respectively. After hydration of the circles with buffer, colonies from growth on selective media or a subculture are applied to the four circles. IB and BGAL reactions are read for a blue-green color after 2 and 15 min, respectively. PRO and GLUT reactions are read at 15 min for a red color after addition of a developer reagent. Identifications obtained with the BactiCard Neisseria were compared with those obtained using conventional procedures for 558 isolates in a blinded fashion. The BactiCard Neisseria identified 100% of 254 Neisseria gonorrhoeae, 100% of 125 Neisseria meningitidis, 53 (98.2%) of 54 Neisseria lactamica, and 123 (98.4%) of 125 Moraxella catarrhalis isolates. The BactiCard Neisseria is an accurate and rapid system for identification of these microorganisms in the clinical laboratory. Electronic Publication     

Genome-wide comparative chromosome maps of <Emphasis Type="Italic">Arvicola amphibius</Emphasis>, <Emphasis Type="Italic">Dicrostonyx torquatus</Emphasis>, and <Emphasis Type="Italic">Myodes rutilus</Emphasis>

The subfamily Arvicolinae consists of a great number of species with highly diversified karyotypes. In spite of the wide use of arvicolines in biological and medicine studies, the data on their karyotype structures are limited. Here, we made a set of painting probes from flow-sorted chromosomes of a male Palearctic collared lemming (Dicrostonyx torquatus, DTO). Together with the sets of painting probes made previously from the field vole (Microtus agrestis, MAG) and golden hamster (Mesocricetus auratus, MAU), we carried out a reciprocal chromosome painting between these three species. The three sets of probes were further hybridized onto the chromosomes of the Eurasian water vole (Arvicola amphibius) and northern red-backed vole (Myodes rutilus). We defined the diploid chromosome number in D. torquatus karyotype as 2n?=?45?+?Bs and showed that the system of sex chromosomes is X1X2Y1. The probes developed here provide a genomic tool-kit, which will help to investigate the evolutionary biology of the Arvicolinae rodents. Our results show that the syntenic association MAG1/17 is present not only in Arvicolinae but also in some species of Cricetinae; and thus, should not be considered as a cytogenetic signature for Arvicolinae. Although cytogenetic signature markers for the genera have not yet been found, our data provides insight into the likely ancestral karyotype of Arvicolinae. We conclude that the karyotypes of modern voles could have evolved from a common ancestral arvicoline karyotype (AAK) with 2n?=?56 mainly by centric fusions and fissions.     

Repeat induced point mutation in two asexual fungi, <Emphasis Type="Italic">Aspergillus niger</Emphasis> and <Emphasis Type="Italic">Penicillium </Emphasis><Emphasis Type="Italic">chrysogenum</Emphasis>

Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi.     

<Emphasis Type="Italic">Leishmania</Emphasis> (<Emphasis Type="Italic">Viannia</Emphasis>) <Emphasis Type="Italic">shawi</Emphasis> purified antigens confer protection against murine cutaneous leishmaniasis

Objective  

Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis.     

<Emphasis Type="Italic">Pepo aphid</Emphasis>-<Emphasis Type="Italic">borne yellows virus</Emphasis>: a new species in the genus <Emphasis Type="Italic">Polerovirus</Emphasis>

Pepo aphid-borne yellows virus (PABYV) has been proposed as a putative representative of a new species in the genus Polerovirus in the family Luteoviridae. The genomes of two South African (SA) isolates of cucurbit-infecting PABYV were described in this record. Total RNA, extracted from a pattypan (Cucurbita pepo L.) and a baby marrow (C. pepo L.) leaf samples, was subjected to next-generation sequencing (NGS) on the HiSeq Illumina platform. Sanger sequencing was subsequently used to authenticate the integrity of PABYV’s genome generated from de novo assembly of the NGS data. PABYV genome of SA isolates consists of 5813 nucleotides and displays an organisation typical of poleroviruses. Genome sequence comparisons of the SA PABYV isolates to other poleroviruses support the classification of PABYV as a new species in the genus Polerovirus. Recombination analyses showed that PABYV and Cucurbit aphid-borne yellows virus (CABYV) shared the same ancestor for the genome part situated between breaking points. Phylogenetic analyses of the RNA-dependent RNA polymerase and the coat protein genes showed that SA PABYV isolates shared distant relationship with CABYV and Suakwa aphid-borne yellows virus. Based on our results, we propose that PABYV is a distinct species in the genus Polerovirus.     

Infections by the Yeast<Emphasis Type="Italic"> Kodomaea</Emphasis> (<Emphasis Type="Italic">Pichia</Emphasis>)<Emphasis Type="Italic"> ohmeri</Emphasis>: Two Cases and Literature Review

A 14-year-old boy who was neutropenic following chemotherapy for leukemia developed fungemia caused by the yeast Kodomaea ohmeri (Pichia ohmeri). The infection was cured by catheter removal and the use of fluconazole. A 74-year-old man who had undergone surgeries for a subcutaneous tumor developed polymicrobic cellulitis involving Kodomaea ohmeri. Despite surgical debridement and antibiotic therapy, the patient died of complications. Including these 2 cases, there have been 10 Kodomaea ohmeri infections reported thus far, all occurring in patients with pre-existing conditions. There have been seven cases of fungemia and one case each of peritonitis, funguria, and cellulitis. The treatment employed varied depending on the site/source of infection. Seven patients recovered and three died. The microbiological data available suggest that Kodomaea ohmeri can be identified definitively by biochemical tests and is susceptible to amphotericin B and either susceptible to or dose dependently susceptible to itraconazole and fluconazole.