A molecular phylogeny of ichthyophiid caecilians (Amphibia: Gymnophiona: Ichthyophiidae): out of India or out of South East Asia?

Recent molecular phylogenetic studies indicate that the rafting Indian plate harboured several isolated vertebrate lineages between ca. 130 and 56 Myr ago that dispersed and diversified 'out of India' following accretion with Eurasia. A single family of the amphibian order Gymnophiona, the Ichthyophiidae, presently occurs on the Indian plate and across much of South East Asia. Ichthyophiid phylogeny is investigated in order to test competing out of India and out of South East Asia hypotheses for their distribution. Partial sequences of mitochondrial 12S and 16S rRNA and cytochrome b genes for 20 ichthyophiids and proximate outgroups were assembled. Parsimony, maximum-likelihood and distance analyses all recover optimum trees in which uraeotyphlids plus Ichthyophis cf. malabarensis are the sister taxa to all other Ichthyophis, among which the South East Asian taxa are monophyletic. Tree topology and branch lengths indicate that the Indian lineages are more basal and older, and thus are more consistent with the hypothesis that ichthyophiids dispersed from the Indian subcontinent into South East Asia. The estimated relationships also support monophyly of Sri Lankan Ichthyophis, and non-monophyly of striped and unstriped Ichthyophis species groups. Mitochondrial DNA sequences provide evidence that should assist current problematic areas of caecilian taxonomy.     

Specific glycanforms of type IX collagen accumulate in embryonic chick sterna after 17 days of development

Type IX collagen is a key component of the extracellular matrix of cartilage where it occurs at the surfaces of type II collagen fibrils as a glycanated molecule. The function of the glycosaminoglycan (GAG) side chain of the molecule is, however, unknown. We have shown that type IX collagen in chicken sternal cartilage is synthesized with a unimodal distribution of GAG chain size, but at post 17 days of development three predominant glycanforms of type IX collagen accumulate. Such accumulation did not occur in sterna from day 15 embryos. In day 17 embryos predominant glycanforms were found in the caudal region of the sternum. By day 19 of development the three predominant glycanforms are widespread throughout the caudal and cephalic regions. The results indicate that developmental and anatomical changes occur to type IX collagen that depend on the size of the GAG chain attached to the alpha2(IX) chain of the molecule.      

Mast cells, Fc epsilon RI, and IL-13 are required for development of airway hyperresponsiveness after aerosolized allergen exposure in the absence of adjuvant

In certain models of allergic airway disease, mast cells facilitate the development of inflammation and airway hyper-responsiveness (AHR). To define the role of the high affinity IgE receptor (FcepsilonRI) in the development of AHR, mice with a disruption of the alpha subunit of the high affinity IgE receptor (FcepsilonRI(-/-)) were exposed on 10 consecutive days to nebulized OVA. Forty-eight hours after the last nebulization, airway responsiveness was monitored by the contractile response of tracheal smooth muscle to electrical field stimulation (EFS). After the 10-day OVA challenge protocol, wild-type mice demonstrated increased responsiveness to EFS, whereas similarly challenged FcepsilonRI(-/-) mice showed a low response to EFS, similar to nonexposed animals. Further, allergen-challenged FcepsilonRI(-/-) mice showed less airway inflammation, goblet cell hyperplasia, and lower levels of IL-13 in lung homogenates compared with the controls. IL-13-deficient mice failed to develop an increased response to EFS or goblet cell hyperplasia after the 10-day OVA challenge. We transferred bone marrow-derived mast cells from wild-type mice to FcepsilonRI(-/-) mice 1 day before initiating the challenge protocol. After the 10-day OVA challenge, recipient FcepsilonRI(-/-) mice demonstrated EFS-induced responses similar to those of challenged wild-type mice. Transferred mast cells could be detected in tracheal preparations. These results show that FcepsilonRI is important for the development of AHR after an aerosolized allergen sensitization protocol and that this effect is mediated through FcepsilonRI on mast cells and production of IL-13 in the lung.     

Impact of genetic counseling and DNA testing on individuals with colorectal cancer with a positive family history: a population-based study

What is the impact of a genetic evaluation for colorectal cancer susceptibility? We previously reported a study of individuals diagnosed with colorectal cancer at 60 years of age or less in a five-county area of New York including Rochester. Subjects reporting at least one first- or second-degree relative with colorectal cancer were invited to receive genetic counseling and DNA testing. Of the 37 persons tested, we previously reported that 6 were found to have deleterious mutations in MSH2 or MLH1. A mutation has since been found in a seventh subject in another laboratory. To evaluate the impact of the testing experience, we followed-up on 36 of these 37 subjects at 3 and 12 months after communicating their DNA test result. We ascertained their knowledge of colon cancer, whether they told relatives their test result, their surveillance behavior, and their mental health. Three months after receiving their result, subjects knew more about colon cancer if they had more cancer of all types in their family (p = 0.02). At 12 months, they knew more if they had been found to have a mutation (p < 0.001), were younger when DNA tested (p < 0.01), or were younger when diagnosed with cancer (p < 0.03). All but 1 of those found to have an abnormality told relatives. Relatives of 3 subjects in whom a mutation had been found came to us to be tested themselves. At 12 months, surveillance for colon and endometrial cancer was more adherent if there were more total cancers in the family (p < 0.05) or if the testee were more worried about cancer (p < 0.05). Self-assessed mental health at 12 months was better for those who were married (p < 0.05). This study suggests that individuals undergoing a genetic evaluation for an inherited susceptibility to colorectal cancer pursue recommended surveillance and inform relatives of their result.     

Effect of liposomes sensitized with methotrexate-gamma-dimyristoylphosphatidylethanolamine on cells that are resistant to methotrexate

This study compares the ability of methotrexate and liposomes, in which the drug is anchored to the lipid bilayers via methotrexate-gamma-dimyristoylphosphatidylethanolamine, to inhibit proliferation of human leukemic cells (CEM/O) and cells derived from this line that are resistant to methotrexate because of either a defective transport system (CEM/MTX cells) or elevated levels of dihydrofolate reductase (CEM/R1 cells). Whereas CEM/O and CEM/MTX cells show a 120-fold difference in their susceptibility to methotrexate (as measured by the incorporation of tritiated deoxyuridine into DNA), both lines are equally sensitive to the liposomes. In contrast, proliferation of CEM/MTX cells is not inhibited significantly by methotrexate-gamma-glycerophosphorylethanolamine (MTX-gamma-glyceroPE), the water-soluble analog of MTX-gamma-DMPE. Both the ability of the liposomes to circumvent the transport defect, and the inability of MTX-gamma-glyceroPE to do so, were anticipated on the basis of previous experiments which show that thiamine pyrophosphate could antagonize inhibition of mouse 3T3 and L1210 cell proliferation by methotrexate and MTX-gamma-glyceroPE, but not inhibition by liposomes. Human cells (CEM/O) behave similarly. The present experiments also suggest that liposomes prepared with MTX-gamma-DMPE can partially reverse the methotrexate resistance of CEM/R1 cells that is due to overproduction of the target enzyme.     

Arabidopsis ATG4 cysteine proteases specificity toward ATG8 substrates

Macroautophagy (hereafter autophagy) is a regulated intracellular process during which cytoplasmic cargo engulfed by double-membrane autophagosomes is delivered to the vacuole or lysosome for degradation and recycling. Atg8 that is conjugated to phosphatidylethanolamine (PE) during autophagy plays an important role not only in autophagosome biogenesis but also in cargo recruitment. Conjugation of PE to Atg8 requires processing of the C-terminal conserved glycine residue in Atg8 by the Atg4 cysteine protease. The Arabidopsis plant genome contains 9 Atg8 (AtATG8a to AtATG8i) and 2 Atg4 (AtATG4a and AtATG4b) family members. To understand AtATG4’s specificity toward different AtATG8 substrates, we generated a unique synthetic substrate C-AtATG8-ShR (citrine-AtATG8-Renilla luciferase SuperhRLUC). In vitro analyses indicated that AtATG4a is catalytically more active and has broad AtATG8 substrate specificity compared with AtATG4b. Arabidopsis transgenic plants expressing the synthetic substrate C-AtAtg8a-ShR is efficiently processed by endogenous AtATG4s and targeted to the vacuole during nitrogen starvation. These results indicate that the synthetic substrate mimics endogenous AtATG8, and its processing can be monitored in vivo by a bioluminescence resonance energy transfer (BRET) assay. The synthetic Atg8 substrates provide an easy and versatile method to study plant autophagy during different biological processes.     

Batrachochytrium dendrobatidis Infection and Lethal Chytridiomycosis in Caecilian Amphibians (Gymnophiona)

Batrachochytrium dendrobatidis (Bd) is commonly termed the ‘amphibian chytrid fungus’ but thus far has been documented to be a pathogen of only batrachian amphibians (anurans and caudatans). It is not proven to infect the limbless, generally poorly known, and mostly soil-dwelling caecilians (Gymnophiona). We conducted the largest qPCR survey of Bd in caecilians to date, for more than 200 field-swabbed specimens from five countries in Africa and South America, representing nearly 20 species, 12 genera, and 8 families. Positive results were recovered for 58 specimens from Tanzania and Cameroon (4 families, 6 genera, 6+ species). Quantities of Bd were not exceptionally high, with genomic equivalent (GE) values of 0.052–17.339. In addition, we report the first evidence of lethal chytridiomycosis in caecilians. Mortality in captive (wild-caught, commercial pet trade) Geotrypetes seraphini was associated with GE scores similar to those we detected for field-swabbed, wild animals.     

Diversity and ecology of algae from the Nahal Qishon river,northern Israel

In 59 samples of periphyton and phytoplankton collected in 2002 - 2003 from the Nahal Qishon (Qishon River), northern Israel, we found 178 species from seven divisions of algae and cyanoprocaryotes. Diatoms, clorophytes, and cyanoprocaryotes prevail. Nitzschia and Navicula (Bacillariophyta) are the most abundant. Most of the species are cosmopolitan or widespread, except Lagynion janei (Chrysophyta), which is endemic for the Mediterranean Realm. About 17% of species (26) are new for Israel and five of them represent the first recorded genera: Crinalium endophyticum Crow, Actinocyclus normanii (Gregory) Hustedt, Rhizoclonium hieroglyphicum (Agardh) Kütz (Chlorophyta), Lagynion janei Bourelly, and Stylococcus aureus Chodat. Most of them come from a rare riverine assemblage with red alga Audouinella pygmea, as well as from the estuarine assemblage. Alkaliphiles predominate among the indicators of acidity, with few acidophiles confined to the communities under the impact of industrial wastes. Among the indicators of salinity, most numerous are the oligohalobien-indifferents and species adapted to a moderate salinity level. The relative species richness of ecological groups and the indices of saprobity are correlated with changes in conductivity, pH, and N-nitrate concentration. Indicators of organic pollution fall in the range of betameso- to alfamesosaprobic self-purification grades. Our studies show ecological significance of the Nahal Qishon as a model for a strongly disturbed aquatic ecosystem in the coastal zone of eastern Mediterranean.