Neogene sloth assemblages (Mammalia,Pilosa) of the Cocinetas Basin (La Guajira,Colombia): implications for the Great American Biotic Interchange

We describe sloth assemblages from the Cocinetas Basin (La Guajira peninsula, Colombia), found in the Neogene Castilletes and Ware formations, located in northernmost South America, documenting otherwise poorly known biotas. The tentative referral of a specimen to a small megatherioid sloth, Hyperleptus?, from the early–middle Miocene Castilletes Formation, suggests affinities of this fauna with the distant Santa Cruz Formation and documents a large latitudinal distribution for this taxon. The late Pliocene Ware Formation is much more diverse, with five distinct taxa representing every family of ‘ground sloths’. This diversity is also remarkable at the ecological level, with sloths spanning over two orders of magnitude of body mass and probably having different feeding strategies. Being only a few hundred kilometres away from the Isthmus of Panama, and a few hundred thousand years older than the classically recognized first main pulse of the Great American Biotic interchange (GABI 1), the Ware Formation furthermore documents an important fauna for the understanding of this major event in Neogene palaeobiogeography. The sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found in North America before GABI 1.     

Solution structure of the lymphocyte receptor Nkrp1a reveals a distinct conformation of the long loop region as compared to in the crystal structure

Mouse Nkrp1a receptor is a C‐type lectin‐like receptor expressed on the surface of natural killer cells that play an important role against virally infected and tumor cells. The recently solved crystal structure of Nkrp1a raises questions about a long loop region which was uniquely extended from the central region in the crystal. To understand the functional significance of the loop, the solution structure of Nkrp1a using nuclear magnetic resonance (NMR) spectroscopy was determined. A notable difference between the crystal and NMR structure of Nkrp1a appears in the conformation of the long loop region. While the extended loop points away from the central core and mediates formation of a domain swapped dimer in the crystal, the solution structure is monomeric with the loop tightly anchored to the central region. The findings described the first solution structure in the Nkrp1 family and revealed intriguing similarities and differences to the crystal structure. Proteins 2016; 84:1304–1311. © 2016 Wiley Periodicals, Inc.     

A high throughput substrate binding assay reveals hexachlorophene as an inhibitor of the ER-resident HSP70 chaperone GRP78

Glucose-regulated protein 78 (GRP78) is the ER resident 70 kDa heat shock protein 70 (HSP70) and has been hypothesized to be a therapeutic target for various forms of cancer due to its role in mitigating proteotoxic stress in the ER, its elevated expression in some cancers, and the correlation between high levels for GRP78 and a poor prognosis. Herein we report the development and use of a high throughput fluorescence polarization-based peptide binding assay as an initial step toward the discovery and development of GRP78 inhibitors. This assay was used in a pilot screen to discover the anti-infective agent, hexachlorophene, as an inhibitor of GRP78. Through biochemical characterization we show that hexachlorophene is a competitive inhibitor of the GRP78-peptide interaction. Biological investigations showed that this molecule induces the unfolded protein response, induces autophagy, and leads to apoptosis in a colon carcinoma cell model, which is known to be sensitive to GRP78 inhibition.     

HSP60/10 chaperonin systems are inhibited by a variety of approved drugs,natural products,and known bioactive molecules

All living organisms contain a unique class of molecular chaperones called 60?kDa heat shock proteins (HSP60 – also known as GroEL in bacteria). While some organisms contain more than one HSP60 or GroEL isoform, at least one isoform has always proven to be essential. Because of this, we have been investigating targeting HSP60 and GroEL chaperonin systems as an antibiotic strategy. Our initial studies focused on applying this antibiotic strategy for treating African sleeping sickness (caused by Trypanosoma brucei parasites) and drug-resistant bacterial infections (in particular Methicillin-resistant Staphylococcus aureus – MRSA). Intriguingly, during our studies we found that three known antibiotics – suramin, closantel, and rafoxanide – were potent inhibitors of bacterial GroEL and human HSP60 chaperonin systems. These findings prompted us to explore what other approved drugs, natural products, and known bioactive molecules might also inhibit HSP60 and GroEL chaperonin systems. Initial high-throughput screening of 3680 approved drugs, natural products, and known bioactives identified 161 hit inhibitors of the Escherichia coli GroEL chaperonin system (4.3% hit rate). From a purchased subset of 60 hits, 29 compounds (48%) re-confirmed as selective GroEL inhibitors in our assays, all of which were nearly equipotent against human HSP60. These findings illuminate the notion that targeting chaperonin systems might be a more common occurrence than we previously appreciated. Future studies are needed to determine if the in vivo modes of action of these approved drugs, natural products, and known bioactive molecules are related to GroEL and HSP60 inhibition.     

Smart is the new sexy: female mountain chickadees increase reproductive investment when mated to males with better spatial cognition

Understanding the evolution of inter and intraspecific variation in cognitive abilities is one of the main goals in cognitive ecology. In scatter‐caching species, spatial memory is critical for the recovery of food caches and overwinter survival, but its effects on reproduction are less clear. Better spatial cognition may improve pre‐breeding condition allowing for earlier reproduction. Alternatively, when mated to males with better spatial memory, females may be able to invest more in reproduction which may allow increased offspring survival and hence higher fitness. Using wild food‐caching mountain chickadees, we found that when environmental conditions were favourable for breeding, females mated to males with better spatial cognition laid larger clutches and fledged larger broods than females mated to males with worse cognitive performance. Our results support the hypothesis that females may increase their reproductive investment to gain indirect, genetic benefits when mated to high‐quality males with better spatial cognitive abilities.     

Intraoperative multispectral and hyperspectral label‐free imaging: A systematic review of in vivo clinical studies

Multispectral and hyperspectral imaging (HSI) are emerging optical imaging techniques with the potential to transform the way surgery is performed but it is not clear whether current systems are capable of delivering real‐time tissue characterization and surgical guidance. We conducted a systematic review of surgical in vivo label‐free multispectral and HSI systems that have been assessed intraoperatively in adult patients, published over a 10‐year period to May 2018. We analysed 14 studies including 8 different HSI systems. Current in‐vivo HSI systems generate an intraoperative tissue oxygenation map or enable tumour detection. Intraoperative tissue oxygenation measurements may help to predict those patients at risk of postoperative complications and in‐vivo intraoperative tissue characterization may be performed with high specificity and sensitivity. All systems utilized a line‐scanning or wavelength‐scanning method but the spectral range and number of spectral bands employed varied significantly between studies and according to the system's clinical aim. The time to acquire a hyperspectral cube dataset ranged between 5 and 30 seconds. No safety concerns were reported in any studies. A small number of studies have demonstrated the capabilities of intraoperative in‐vivo label‐free HSI but further work is needed to fully integrate it into the current surgical workflow.      

Evaluation of a novel agarose-based synthetic ligand adsorbent for the recovery of antibodies from ovine serum

This paper evaluates a prototype agarose-based affinity adsorbent utilizing a bound synthetic ligand designed to replace Protein A as an IgG-affinity capture resin and compares its purification characteristics with four commercially available matrices for the recovery of polyclonal antibodies from crude hyperimmune ovine serum. The novel adsorbent was found to show the highest dynamic capacity (29.2 mg/mL) of all matrices under evaluation--30% higher than the other commercial adsorbents evaluated. When using a post-load caprylic acid wash, IgG yields of over 85% and purities of over 90% were achieved consistently over multiple loading cycles. To evaluate bead diffusion, inverted confocal microscopy was used to visualise fluorescent antibody binding on to individual adsorbent beads in real time. The results indicate that the binding characteristics of the prototype adsorbent are similar to those obtained with Protein G Sepharose. This study indicates that the high-capacity prototype matrix is a feasible and potentially cost-effective alternative for the direct capture of antibodies from crude ovine serum and may therefore also be applicable to the purification of other complex industrial feedstocks such as transgenic milk or monoclonal antibodies expressed using recombinant technologies.     

Characterisation of an industrial affinity process used in the manufacturing of digoxin-specific polyclonal Fab fragments

This paper describes the effect of several variables on the affinity process for the production of the FDA approved biotherapeutic product Digoxin Immune Fab (Ovine) (DigiFab, Protherics Inc., TN, USA). The study considers the effects of column re-use on matrix capacity and on the subsequent recovery of the antibody product, and the impact of varying column loading on matrix performance. The methodology used could be equally applied to assess the feasibility of using an affinity matrix for commercial scale purification of alternative antibody derived biotherapeutics. The capacity and specific Fab recovery were calculated through 24h equilibrium and mass balance studies. Results were assessed against data obtained through confocal scanning laser microscopy. Scale-down experiments produced specific Fab recoveries and purities that were comparable with those at production scale. The matrix capacity was found to be 45+/-15 mg of Fab/ml of matrix. Through the use of fluorescent DigiFab and confocal scanning techniques, Fab uptake onto single affinity bead was evaluated. Average intensity values calculated for each sample provided direct real-time, measure of Fab binding and matrix capacity. The results suggest that the affinity matrix had a limited reuse life as a drop in recovery is observed following the completion of a small number of process cycles (30% after three runs). The findings support that which is seen at the current manufacturing scale, where the affinity column is used for a limited number of runs. Results from this study can be used as a basis for future optimisation of this purification process.     

Integrative Approach Uncovers New Patterns of Ecomorphological Convergence in Slow Arboreal Xenarthrans

Journal of Mammalian Evolution - Identifying ecomorphological convergence examples is a central focus in evolutionary biology. In xenarthrans, slow arboreality independently arose at least three...