Isolation and Pathogenicity of Rhizosphere Fungi of Cocoyam in Relation to Cocoyam Root Rot Disease

Cocoyam is the second most important staple crop of Cameroon and root rot is a destructive disease of this plant. Pythium myriotylum (Pm), Fusarium solani (Fs), and Rhizoctonia solani (Rs) were isolated from the rhizosphere of root rot affected cocoyams and from the soil of a cocoyam experimental field plot temporarily devoid of same in Mamu, Cameroon. Pm was isolated from the above soil by the cocoyam leaf disc baits. Fs and Rs were also isolated from the same soils by the water dilution method and from the roots of diseased cocoyams but were always associated with mycelial growth of Pm. Pathogenicity of Pm and in combinations with Fs or Rs or Fs + Rs all developed cocoyam root rot disease (CRRD) symptoms on 3– and 7–month old cocoyam plantlets 2–7 days after inoculation. Symptoms included rotted roots and wilting with general chlorosis of inoculated plantlets. No symptoms of CRRD were noted on cocoyam plantlets inoculated with Fs, Rs, Fs + Rs, and distilled water. Results indicated that CRRD is not caused by several pathogens but only by Pm. Pm isolates from the soils and roots of diseased cocoyams and those maintained in the ROTREP laboratory have significantly bigger diameter of mycelial colony growth in 24 h–period at 31 °C on lima bean sucrose agar, V–8 juice sucrose agar, and potato sucrose agar than on potato dextrose agar and 2 % water agar. The cocoyam plantlets were raised axenically from tissue culture of explants in the laboratory.     

Kinetics of 14C-cholic acid in the baboon under normal conditions and in cholestasis. Description and validity of a multicompartmental model]

A multicompartmental model was applied to the study of the plasmatic and biliary kinetics of the 14C-Cholic acid intravenously injected into a baboon in normal and cholestatic condition. For the evaluation of transfer rates FORTAN IV procedures were used, utilizing Powell method. The degree of fitting was: in normal condition in serum 7% for free and 35% for conjugated Cholic acid, while in bile 5% and 4% respectively; in serum in cholestatic condition 7% for free and 12% for conjugates. The high degree of fitting and reliable estimation of transfer rates suggest that the multicompartmental model applied represents most likely the physio-pathological conditions studied.     

A radioimmunoassay for lithocholic acid conjugates in human serum and liver tissue

A sensitive and specific radioimmunoassay for glycine and taurine conjugates of lithocholic acid (CLCA) has been developed. ³H-glycolithocholic acid (S.A. = 17Ci/mmol) was used as tracer. Separation of free from antibody-bound bile acid was carried out using ammonium sulphate (saturated solution). The antiserum showed high specificity for both glyco and tauro conjugated lithocholate (100% cross reaction) and lithocholic acid (25% cross reaction). The sensitivity of the assay (1 pmole/tube), was adequate for measuring CLCA in peripheral blood and hepatic tissue in man.     

Carbenoxolone Blocks Endotoxin-Induced Protein Kinase R (PKR) Activation and High Mobility Group Box 1 (HMGB1) Release

The pathogen- and damage-associated molecular patterns (for example, bacterial endotoxin and adenosine 5′-triphosphate [ATP]) activate the double-stranded RNA-activated protein kinase R (PKR) to trigger the inflammasome-dependent high mobility group box 1 (HMGB1) release. Extracellular ATP contributes to the inflammasome activation through binding to the plasma membrane purinergic P2X₇ receptor (P2X₇R), triggering the opening of P2X₇R channels and the pannexin-1 (panx-1) hemichannels permeable for larger molecules up to 900 daltons. It was previously unknown whether panx-1 channel blockers can abrogate lipopolysaccharide (LPS)-induced PKR activation and HMGB1 release in innate immune cells. Here we demonstrated that a major gancao (licorice) component (glycyrrhizin, or glycyrrhizic acid) derivative, carbenoxolone (CBX), dose dependently abrogated LPS-induced HMGB1 release in macrophage cultures with an estimated IC₅₀ ≈ 5 μmol/L. In an animal model of polymicrobial sepsis (induced by cecal ligation and puncture [CLP]), repetitive CBX administration beginning 24 h after CLP led to a significant reduction of circulating and peritoneal HMGB1 levels, and promoted a significant increase in animal survival rates. As did P2X₇R antagonists (for example, oxidized ATP, oATP), CBX also effectively attenuated LPS-induced P2X₇R/panx-1 channel activation (as judged by Lucifer Yellow dye uptake) and PKR phosphorylation in primary peritoneal macrophages. Collectively, these results suggested that CBX blocks LPS-induced HMGB1 release possibly through impairing PKR activation, supporting the involvement of PKR in the regulation of HMGB1 release.     

Amyotrophic lateral sclerosis-linked FUS/TLS alters stress granule assembly and dynamics

Background

Amyotrophic lateral sclerosis (ALS)-linked fused in sarcoma/translocated in liposarcoma (FUS/TLS or FUS) is concentrated within cytoplasmic stress granules under conditions of induced stress. Since only the mutants, but not the endogenous wild-type FUS, are associated with stress granules under most of the stress conditions reported to date, the relationship between FUS and stress granules represents a mutant-specific phenotype and thus may be of significance in mutant-induced pathogenesis. While the association of mutant-FUS with stress granules is well established, the effect of the mutant protein on stress granules has not been examined. Here we investigated the effect of mutant-FUS on stress granule formation and dynamics under conditions of oxidative stress.

Results

We found that expression of mutant-FUS delays the assembly of stress granules. However, once stress granules containing mutant-FUS are formed, they are more dynamic, larger and more abundant compared to stress granules lacking FUS. Once stress is removed, stress granules disassemble more rapidly in cells expressing mutant-FUS. These effects directly correlate with the degree of mutant-FUS cytoplasmic localization, which is induced by mutations in the nuclear localization signal of the protein. We also determine that the RGG domains within FUS play a key role in its association to stress granules. While there has been speculation that arginine methylation within these RGG domains modulates the incorporation of FUS into stress granules, our results demonstrate that this post-translational modification is not involved.

Conclusions

Our results indicate that mutant-FUS alters the dynamic properties of stress granules, which is consistent with a gain-of-toxic mechanism for mutant-FUS in stress granule assembly and cellular stress response.

     

Ecology,conservation, and phylogenetic position of the Madagascar Jacana Actophilornis albinucha

The Madagascar Jacana Actophilornis albinucha (Jacanidae) is an endemic shorebird found in the threatened wetlands of western Madagascar. This species is presumed to exhibit classical polyandry; however, few data are available to support that assumption. More generally, a lack of basic understanding of this species hinders conservation efforts. We conducted the most extensive study of the Madagascar Jacana to date, and report on its: 1) distribution, population size and density; 2) degree of sexual size dimorphism; and 3) phylogenetic position. The surveys were conducted at 54 lakes, between January and October in 2016. Madagascar Jacana were found at 22 lakes, and within these were distributed at a mean density of 3.5 ± 0.74 [SE] individuals per hectare of surveyed habitat. We estimate the global population size to be between 975 and 2 064 individuals, and habitat destruction appears to be the main threat to the species. Females were significantly larger than males, consistent with reports for other Jacanidae species. Using a mitochondrial DNA fragment, we expanded the Jacanidae genetic phylogeny, and confirmed that Madagascar Jacana is the sister species to the African Jacana Actophilornis africanus. Further studies are urgently needed to thoroughly re-assess the threat status and population trend of the Madagascar Jacana.     

Is it possible to define a better ASCUS class in cervicovaginal screening? A review of 187 cases

OBJECTIVE: To try to better define the cytologic diagnosis of atypical squamous cells of undetermined significance (ASCUS) in a cervical screening protocol. STUDY DESIGN: Smears from 187 patients with cytologic diagnoses of ASCUS and histologic or two years' cytologic/colposcopic follow-up were reviewed. When an ASCUS diagnosis was confirmed, it was done strictly on the basis of the morphologic criteria recommended by the Regione Emilia Romagna Screening Protocol in 1997, trying also to subclassify ASCUS into favor reactive or favor neoplasia. RESULTS: Seventy ASCUS cases were negative (37.4%). Three cases (1.6%) were low grade squamous intraepithelial lesion, and seven (3.8%) were high grade squamous intraepithelial lesion. One hundred seven ASCUS cases (57.2%) were confirmed. Among the 70 negative cases, 36 (51.4%) had reactive changes on biopsy, 30 (42.9%) koilocytosis, 3 cervical intraepithelial neoplasia (CIN 1) and one CIN not otherwise specified (5.7% total). CONCLUSION: Reclassification of ASCUS cases using tighter criteria reduced them to a rate of 57.2% but missed 30 patients with histologic diagnoses of koilocytosis and 4 with histologic diagnoses of CIN.     

Contrasting genetic diversity and population structure among three sympatric Madagascan shorebirds: parallels with rarity,endemism, and dispersal

Understanding the relative contributions of intrinsic and extrinsic factors to population structure and genetic diversity is a central goal of conservation and evolutionary genetics. One way to achieve this is through comparative population genetic analysis of sympatric sister taxa, which allows evaluation of intrinsic factors such as population demography and life history while controlling for phylogenetic relatedness and geography. We used ten conserved microsatellites to explore the population structure and genetic diversity of three sympatric and closely related plover species in southwestern Madagascar: Kittlitz's plover (Charadrius pecuarius), white‐fronted plover (C. marginatus), and Madagascar plover (C. thoracicus). Bayesian clustering revealed strong population structure in the rare and endemic Madagascar plover, intermediate population structure in the white‐fronted plover, and no detectable population structure in the geographically widespread Kittlitz's plover. In contrast, allelic richness and heterozygosity were highest for the Kittlitz's plover, intermediate for the white‐fronted plover and lowest for the Madagascar plover. No evidence was found in support of the “watershed mechanism” proposed to facilitate vicariant divergence of Madagascan lemurs and reptiles, which we attribute to the vagility of birds. However, we found a significant pattern of genetic isolation by distance among populations of the Madagascar plover, but not for the other two species. These findings suggest that interspecific variation in rarity, endemism, and dispersal propensity may influence genetic structure and diversity, even in highly vagile species.     

Cholinergic anti-inflammatory pathway activity and High Mobility Group Box-1 (HMGB1) serum levels in patients with rheumatoid arthritis

High Mobility Group Box-1 (HMGB1) is a cytokine implicated in the pathogenesis of rheumatoid arthritis (RA) and other inflammatory diseases. The cholinergic anti-inflammatory pathway, a vagus nerve-dependent mechanism, inhibits HMGB1 release in experimental disease models. Here, we examine the relationship between vagus nerve activity and HMGB1 in patients with RA. We compared RR interval variability, an index of cardiac vagal modulation, HMGB1 and hsCRP serum levels, and disease activity scores in thirteen RA patients and eleven age- and sex-matched controls. In RA patients, serum levels of HMGB1 and hsCRP were elevated as compared with controls (HMGB1=71 ng/mL [45-99] vs. 18 ng/mL [0-40], P<0.0001; hsCRP=14.5 mg/L [0.7-59] vs. 1 mg/L [0.4-2.9], P<0.001). RR interval variability in RA patients was significantly decreased as compared with controls (HF=38 msec2 [14-80] vs. 288 msec2 [38-364], P<0.0001; rMSSD=20.9+/-9.79 msec, 52.6+/-35.3 msec, P<0.01). HMGB1 levels and RR interval variability were significantly related (rho=-0.49, P<0.01). HMGB1 serum levels significantly correlated with disease activity scores (DAS-28) in patients with RA (P=0.004). The study design does not enable a determination of causality, but the results are consistent with the hypothesis that decreased cholinergic anti-inflammatory pathway activity is associated with increased HMGB1 levels in patients with RA.