An electron microscopic histochemical and X-ray microprobe study of spherites in a mussel

Transmission electron microscopic, histochemical and X-ray analytical microprobe techniques were used to study the inorganic-organic relationship in the spherites (calcospherules) from the mantle, i.e. subadjacent to the outer mantle epithelium, of the fresh-water mussel Amblema. These structures were shown to contain calcium which could be chelated by the flotation of sections on solutions of either formic acid or ethylene glycol bis-(beta-amino ethyl ether)-N, N1-tetra-acetic acid (EGTA), Analysis of both non-chelated and sections revealed a significant sulfur peak. Chelated spherites were also intensely stained with acid phosphotungstic acid (PTA), Such data is indicative of the presence of an organic glycoprotein (proteoglycan) matrix which could serve to bind mineral ions, thus forming organic-inorganic aggregates for calcium transport and homeostasis. In this regard, the spherites are analogous to both calcium phosphate containing mitochondrial granules and the initial calcification sites in vertebrate mineralizing tissues.     

Repeated Acetylcholine Receptor Antibody-Concentrations and Association to Clinical Myasthenia Gravis Development

Introduction

We aimed to examine the longitudinal association between Myasthenia Gravis (MG) clinical severity and concentration of acetylcholine receptor (AChR)-antibodies to evaluate if AChR-antibody variations correlate to disease severity. A positive AChR-antibody test is specific for MG.

Material and Methods

All patients from western Norway who had two or more AChR- antibody tests in the period 1983–2013 were identified. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification was used to grade disease development. Multiple ordinal logistic regression analysis was used to estimate a possible predictive effect for AChR-antibody concentration on MGFA classification result.

Results

In 67 patients two or more AChR-antibody tests with a corresponding MGFA-score were performed, with a total of 309 tests. 56 patients were treated with immunosuppressive drugs and 11 by pyridostigmine only. There was a positive association between concentration of AChR-antibodies and longitudinal MGFA-score for the subgroup with immunosuppressive treatment, but not for those treated with pyridostigmine only. This association between AChR-antibody concentration and MGFA score declined with increasing time since onset (p = 0.005 for the interaction of group×time×concentration).

Conclusions

For MG patients with immunosuppressive treatment, repeated AChR-antibody measurements give information about clinical development, and can therefore be of support in therapeutic decisions.     

Defence-related Enzymes in Pepper Roots During Interactions with Arbuscular Mycorrhizal Fungi and/or Verticillium dahliae

Previous studies have described that arbuscular mycorrhizal fungi (AMF) can reduce the deleterious effect of Verticillium dahliae Kleb. on pepper growth and yield. In mycorrhizal plants, the bioprotection against soil-borne pathogens can result from the preactivation of defence responses that include some structural modifications and the accumulation of Pathogenesis-Related (PR) proteins. Our first objective was to study if V. dahliae induced defence mechanisms in roots before infected pepper developed visible symptoms of disease. The second aim was to determine if AMF induced defence-related enzymatic activities in pepper roots before or after pathogen’s attack. Results showed that the colonization of pepper roots by Glomus deserticola (Trappe, Bloss and Menge) induced the appearance of new isoforms of acidic chitinases, superoxide dismutase (SOD) and, at early stages, peroxidases. In contrast, V. dahliae neither stimulated the phenylpropanoid pathway nor elicited hydrolytic activities in infected pepper roots. Only in mycorrhizal plants, the inoculation with V. dahliae slightly increased both phenylalanine ammonia-lyase (PAL) and peroxidase activities two weeks later. Mycorrhizal-specific induction of new isoforms of acidic chitinases and SOD together with enhanced peroxidase and PAL activities 2 weeks after pathogen inoculation could be involved in the biocontrol of Verticillium-induced wilt in pepper by AMF.     

Is gender difference in postnatal thyroid growth associated with specific expression patterns of androgen and estrogen receptors?

Variations in sex steroids bioavailability were linked to the gender difference in the growth of thyroid glands of neonatal rats. In the present study we tested androgen receptor (AR) and estrogen receptor (ER) concentrations by ligand binding assay, and expression of their genes by RT-PCR and Western blot in the thyroid glands of neonatal rats. AR concentration remained elevated from postnatal day (PND) 10 onwards in males, whereas it decreased by PND 20 in females. AR mRNA and protein expressions were higher in males than females, which increased by PND 10, decreased after PND 15 and reached the nadir by PND 20. ER concentration increased by PND 10 and decreased thereafter in both sex. ERα mRNA expression diminished by PND 15 in both sex; while ERβ mRNA decreased by PND 15 to reach the nadir by PND 20 in males, it was augmented by PND 10 in females to reach the peak by PND 15 and diminished by PND 20. ERα protein expression increased by PND 10 and remained elevated till PND 20 in both sex. ERβ protein expression in males increased by PND 10 and decreased by PND 20, while it remained static up to PND 15 and decreased in females. Testosterone stimulated [³H]-thymidine uptake and the expression of IGF-1 and NIS genes in thyrocytes of both sex in vitro, while estradiol stimulated them in females but not in males. We conclude that androgens influence the growth and differentiation of thyrocytes through augmented expression of AR, IGF-1 and NIS in either sex, whereas estrogen imparts the gender difference, which may be at a level beyond the expression of ERs.     

Application of antimicrobial polypeptide host defenses to aquaculture: Exploitation of downregulation and upregulation responses

Antimicrobial polypeptides (AMPPs), consisting of peptides and small proteins with antimicrobial activity, are an integral component of innate immunity. Their often potent properties and widespread prevalence in fish suggests that designing means of manipulating their levels has considerable potential for maintaining or improving fish health. There is evidence that a number of chronic stresses lead to significant downregulation of AMPPs and thus their monitoring could be a highly sensitive measure of health status and risk of an infectious disease outbreak. Conversely, upregulation of AMPP expression could be used to enhance disease resistance in stressful environments, as well as improve the efficacy of traditional antimicrobial drugs. However, further work is required in linking levels of a number of AMPPs to physiological function since, while a number of studies have documented the down- or upregulation of AMPPs via gene expression, relatively few studies have quantitatively examined changes in protein expression. In addition, not all AMPPs appear to be expressed at microbicidal levels in vivo, suggesting that at least some may have functions other than being directly protective. Nonetheless, in fish, there is evidence that some constitutively expressed AMPPs, such as piscidins and histone-like proteins, are expressed at microbicidal levels and that they decline with stress. Furthermore, certain AMPPs derived from hemoglobin-β are upregulated to microbicidal levels after experimental challenge. The likely widespread distribution of these three AMPP groups in fish provides the opportunity to design strategies to greatly improve the health of cultured fish populations.     

Gut microbial ecology of the Critically Endangered Fijian crested iguana (Brachylophus vitiensis): Effects of captivity status and host reintroduction on endogenous microbiomes

Animals often exhibit distinct microbial communities when maintained in captivity as compared to when in the wild. Such differentiation may be significant in headstart and reintroduction programs where individuals spend some time in captivity before release into native habitats. Using 16S rRNA gene sequencing, we (i) assessed differences in gut microbial communities between captive and wild Fijian crested iguanas (Brachylophus vitiensis) and (ii) resampled gut microbiota in captive iguanas released onto a native island to monitor microbiome restructuring in the wild. We used both cloacal swabs and fecal samples to further increase our understanding of gut microbial ecology in this IUCN Critically Endangered species. We found significant differentiation in gut microbial community composition and structure between captive and wild iguanas in both sampling schemes. Approximately two months postrelease, microbial communities in cloacal samples from formerly captive iguanas closely resembled wild counterparts. Interestingly, microbial communities in fecal samples from these individuals remained significantly distinct from wild conspecifics. Our results indicate that captive upbringings can lead to differences in microbial assemblages in headstart iguanas as compared to wild individuals even after host reintroduction into native conditions. This investigation highlights the necessity of continuous monitoring of reintroduced animals in the wild to ensure successful acclimatization and release.     

N-terminal peptide sequence of goat-beta-lactoglobulin.

Three cyanogen bromide peptides from native goat beta-lactoglobulin have been isolated by gel-filtration. The N-terminal fragment has been identified and its sequence was determined to be: Ile-Val-Thr-Gln-Thr-. The results are compared with the N-terminal region of cow beta-lactoglobulins A and B.     

Transient opening of tricellular vertices controls paracellular transport through the follicle epithelium during Drosophila oogenesis

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Characterization of a rat liver epithelial cell line to detect inhibitors of metabolic cooperation

Summary A normal rat liver epithelial cell line, with phenotype characteristics of “oval” cells (WB-F344), was examined for its ability to perform gap-junctional intercellular communication as measured by metabolic cooperation. To test for gap-junctional intercellular communication, 6-thioguanine-sensitive cells were cocultivated with 6-thioguanine-resistant cells. It was found that the recovery of 6-thioguanine-resistant cells depended on the densities of the 6-thioguanine-sensitive cells. Higher densities of 6-thioguanine-sensitive cells reduced the recovery of 6-thioguanine-resistant cells. These observations demonstrate that rat liver epithelial cells could metabolically cooperate, implying they could perform gap-junctional intercellular communication. Two tumor-promoting organochlorine pesticides, aldrin and dieldrin, were potent inhibitors of metabolic cooperation for these cells, but 12-0-tetradecanoyl-phorbol-13-acetate and teleocidin, known mouse skin tumor promoters, were not significantly effective in inhibiting metabolic cooperation. The results suggest that these cells might provide the basis for an in vitro assay specifically to study liver tumor promoters. Research was sponsored by a grant from the Air Force Office of Scientific Research, Air Force Systems Command, USAF, under grant AFOSR-86-0084. The U. S. Government is authorized to reproduce and distribute reprints for government purposes notwithstanding any copyright notation thereon.