Cobalamin producers and prokaryotic consumers in the Northwest Atlantic

Cobalamin availability can influence primary productivity and ecological interactions in marine microbial communities. The characterization of cobalamin sources and sinks is a first step in investigating cobalamin dynamics and its impact on productivity. Here, we identify potential cobalamin sources and sinks on the Scotian Shelf and Slope in the Northwest Atlantic Ocean. Functional and taxonomic annotation of bulk metagenomic reads, combined with analysis of genome bins, were used to identify potential cobalamin sources and sinks. Cobalamin synthesis potential was mainly attributed to Rhodobacteraceae, Thaumarchaeota, and cyanobacteria (Synechococcus and Prochlorococcus). Cobalamin remodelling potential was mainly attributed to Alteromonadales, Pseudomonadales, Rhizobiales, Oceanospirilalles, Rhodobacteraceae, and Verrucomicrobia, while potential cobalamin consumers include Flavobacteriaceae, Actinobacteria, Porticoccaceae, Methylophiliaceae, and Thermoplasmatota. These complementary approaches identified taxa with the potential to be involved in cobalamin cycling on the Scotian Shelf and revealed genomic information required for further characterization. The Cob operon of Rhodobacterales bacterium HTCC2255, a strain with known importance in cobalamin cycling, was similar to a major cobalamin producer bin, suggesting that a related strain may represent a critical cobalamin source in this region. These results enable future inquiries that will enhance our understanding of how cobalamin shapes microbial interdependencies and productivity in this region.     

Effect of Aging on Tyrosine Hydroxylase Protein Content and the Relative Number of Dopamine Nerve Terminals in Human Caudate

This study examined the effect of aging on the relative number of dopamine (DA) nerve terminals in human caudate nucleus, their content of tyrosine hydroxylase (TH) protein, and the relative abundance of TH monomers with different molecular weights. Preliminary studies on brain tissue cryopreservation, performed with rat striatum, indicated that intact synaptosomes can be prepared from fresh tissue slowly frozen in 0.32 M sucrose with 5% dimethyl sulfoxide and then thawed rapidly prior to synaptosome preparation. Synaptosomes were prepared in this manner from postmortem caudate nucleus tissue obtained from normal humans 1 month to 63 years of age. To determine the relative number of DA nerve terminals for each individual, dopaminergic synaptosomes were selectively labeled with a monoclonal antibody to TH and quantified by fluorescence-activated cell sorting. To determine the relative amount of TH protein for each individual, the concentration of TH protein in the same synaptosomal preparations was determined using immunoblots. Our results suggest that caudate TH levels plateau soon after birth and tend to remain relatively stable during aging, since no changes in either the relative number of TH-containing nerve terminals or the concentration of TH protein were found in subjects 15-63 years of age. In light of previous studies showing an age-related loss of DA cell bodies, these findings suggest that remaining DA neurons compensate to maintain caudate levels of TH protein and TH-containing nerve terminals. Immunoblot studies identified three forms of TH monomer (60.6, 61.7, and 65.1 kDa), indicating that mRNAs coding for high molecular mass forms of TH may be actively translated in human brain. No age-related differences in the relative abundance of these forms were found.     

Central nervous system actions of 2, 5-bis (3,4-dimethoxybenzyl) cyclopentyl amine,a peripheral dopamine blocking agent

The behavioral and brain catecholamine effects of 2,5-bis (3,4-dimethoxybenzyl) cyclopentyl amine were investigated in mice. It rapidly depleted norepinephrine. Chronic dosing also depleted dopamine, but to a lesser degree. As indicated by a lack of effect on amphetamine induced stereotypy and apomorphine induced emesis and failure to induce catalepsy, the compound does not block brain dopamine receptors. It has no effect on brain catecholamine synthesis or dopamine-β-hydroxylase activity.     

Unusual presentation of choriocarcinoma

Background  

Choriocarcinoma is an aggressive neoplasm arising in the body of the uterus. The disease normally spreads to lung and brain.     

Structure of the major peanut allergen Ara h 1 may protect IgE-binding epitopes from degradation

In the past decade, there has been an increase in allergic reactions to peanut proteins, sometimes resulting in fatal anaphylaxis. The development of improved methods for diagnosis and treatment of peanut allergies requires a better understanding of the structure of the allergens. Ara h 1, a major peanut allergen belonging to the vicilin family of seed storage proteins, is recognized by serum IgE from >90% of peanut-allergic patients. In this communication, Ara h 1 was shown to form a highly stable homotrimer. Hydrophobic interactions were determined to be the main molecular force holding monomers together. A molecular model of the Ara h 1 trimer was constructed to view the stabilizing hydrophobic residues in the three dimensional structure. Hydrophobic amino acids that contribute to trimer formation are at the distal ends of the three dimensional structure where monomer-monomer contacts occur. Coincidentally, the majority of the IgE-binding epitopes are also located in this region, suggesting that they may be protected from digestion by the monomer-monomer contacts. On incubation of Ara h 1 with digestive enzymes, various protease-resistant fragments containing IgE-binding sites were identified. The highly stable nature of the Ara h 1 trimer, the presence of digestion resistant fragments, and the strategic location of the IgE-binding epitopes indicate that the quaternary structure of a protein may play a significant role in overall allergenicity.     

Best practice BioBanking of human heart tissue

This review provides a guide to researchers who wish to establish a biobank. It also gives practical advice to investigators seeking access to samples of healthy or diseased human hearts. We begin with a brief history of the Sydney Heart Bank (SHB) from when it began in 1989, including the pivotal role played by the late Victor Chang. We discuss our standard operating procedures for tissue collection which include cryopreservation and the quality assurance needed to maintain the long-term molecular and cellular integrity of the samples. The SHB now contains about 16,000 heart samples derived from over 450 patients who underwent isotopic heart transplant procedures and from over 100 healthy organ donors. These enable us to provide samples from a wide range of categories of heart failure. So far, we have delivered heart samples to more than 50 laboratories over two decades, and we answer their most frequently asked questions. Other SHB services include the development of tissue microarrays (TMA). These enable end users to perform preliminary examinations of the expression and localisation of target molecules in diseased or aging donor hearts, all in a single section of the TMA. Finally, the processes involved in managing tissue requests from external users and logistics considerations for the shipment of human tissue are discussed in detail.

Electronic supplementary material

The online version of this article (doi:10.1007/s12551-015-0182-6) contains supplementary material, which is available to authorized users.     

Differential expression level of cytokeratin 8 in cells of the bovine nucleus pulposus complicates the search for specific intervertebral disc cell markers

Introduction  

Development of cell therapies for repairing the intervertebral disc is limited by the lack of a source of healthy human disc cells. Stem cells, particularly mesenchymal stem cells, are seen as a potential source but differentiation strategies are limited by the lack of specific markers that can distinguish disc cells from articular chondrocytes.