The Terminal Protonephridial Complex of Haplopharynx rostratus (Platyhelminthes,Haplopharyngida)

The terminal protonephridial complex of Haplopharynx rostratus consists of three terminal cells. There are no weirs consisting of ribs connected by a filtration “membrane”, but some cytoplasmic outgrowths into the lumen of the terminal cells. Excretion is by exocytotic vesicles. The terminal cells also contain Golgi complexes and large membrane-bound vacuoles containing electron-dense material. The ciliary bundles (flames) of terminal cells 2 and 3 protrude into the lumen of the centrally located terminal cell I. The complex is surrounded by a sheath containing numerous filaments. The terminal complex of H. rostratus resembles that of the macrostomid Paromalostomum proceracauda, lending support to the view that the two taxa are closely related. © 1998 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd. All rights reserved     

In vitro Inhibition of Clinical Isolates of Otitis Media Pathogens by the Probiotic Streptococcus salivarius BLIS K12

Otitis media is a common childhood infection, frequently requiring antibiotics. With high rates of antibiotic prescribing and increasing antibiotic resistance, new strategies in otitis media prevention and treatment are needed. The aim of this study was to assess the in vitro inhibitory activity Streptococcus salivarius BLIS K12 against otitis media pathogens. Efficacy of the bacteriocin activity of S. salivarius BLIS K12 against the otitis media isolates was assessed using the deferred antagonism test. Overall, 48% of pathogenic isolates exhibited some growth inhibition by S. salivarius BLIS K12. S. salivarius BLIS K12 can inhibit the in vitro growth of the most common pathogens.

     

Dynamic compressive loading differentially regulates chondrocyte anabolic and catabolic activity with age

Dynamic loading has emerged as an important part of cartilage tissue engineering strategies for enhancing tissue production and producing cartilage with functionally competent mechanical properties. As patients in need of cartilage span a range of age groups, questions arise as to the role of age in a cell's ability to respond to dynamic loading. Therefore, this study's goal was to characterize age‐related anabolic and catabolic responses of chondrocytes to dynamic compressive loading. Bovine chondrocytes isolated from juvenile (3‐week‐old) and adult (2‐ to 3‐year‐old) donors were encapsulated in poly(ethylene glycol) hydrogels and subjected to dynamic loading applied intermittently in a sinusoidal waveform at 1 or 0.3 Hz with 5 or 10% amplitude strain up to 2 weeks. Loading significantly enhanced total sulfated glycosaminoglycan (sGAG) production by 220% for juvenile chondrocytes with 0.3 Hz/5% loading and by 88% for adult chondrocytes with 1 Hz/5% loading, while all other loading regimes did not affect or inhibited total sGAG production. Contrarily, deposition of larger matrix molecules of aggrecan and collagen II was either not affected or inhibited by loading. Collagen VI deposition was significantly upregulated by loading but only in adult chondrocytes and under different loading regimes (1 Hz/10% and 0.3 Hz/5%) when compared to total sGAGs. Both cell populations displayed catabolic activity, which appeared to be stimulated by loading. Taken together, findings from this study suggest that loading differentially regulates matrix synthesis and the response is highly dependent on donor age. Biotechnol. Bioeng. 2013; 110: 2046–2057. © 2013 Wiley Periodicals, Inc.     

Bringing Back a Healthy Buzz? Invertebrate Parasites and Reintroductions: A Case Study in Bumblebees

Reintroductions can play a key role in the conservation of endangered species. Parasites may impact reintroductions, both positively and negatively, but few case studies of how to manage parasites during reintroductions exist. Bumblebees are in decline at regional and global scales, and reintroductions can be used to re-establish extinct local populations. Here we report on how the risks associated with parasites are being managed in an ongoing reintroduction of the short-haired bumblebee, Bombus subterraneus, to the UK. Disease risk analysis was conducted and disease risk management plans constructed to design a capture-quarantine-release system that minimised the impacts on both the bumblebees and on their natural parasites. Given that bumblebee parasites are (i) generalists, (ii) geographically ubiquitous, and (iii) show evidence of local adaptation, the disease risk management plan was designed to limit the co-introduction of parasites from the source population in Sweden to the destination site in the UK. Results suggest that this process at best eliminated, or at least severely curtailed the co-introduction of parasites, and ongoing updates of the plan enabled minimization of impacts on natural host-parasite dynamics in the Swedish source population. This study suggests that methods designed for reintroductions of vertebrate species can be successfully applied to invertebrates. Future reintroductions of invertebrates where the parasite fauna is less well known should take advantage of next-generation barcoding and multiple survey years prior to the start of reintroductions, to develop comprehensive disease risk management plans.

     

MTH1 Substrate Recognition—An Example of Specific Promiscuity

MTH1 (NUDT1) is an oncologic target involved in the prevention of DNA damage. We investigate the way MTH1 recognises its substrates and present substrate-bound structures of MTH1 for 8-oxo-dGTP and 8-oxo-rATP as examples of novel strong and weak binding substrate motifs. Investigation of a small set of purine-like fragments using 2D NMR resulted in identification of a fragment with weak potency. The protein-ligand X-Ray structure of this fragment provides insight into the role of water molecules in substrate selectivity. Wider fragment screening by NMR resulted in three new protein structures exhibiting alternative binding configurations to the key Asp-Asp recognition element of the protein. These inhibitor binding modes demonstrate that MTH1 employs an intricate yet promiscuous mechanism of substrate anchoring through its Asp-Asp pharmacophore. The structures suggest that water-mediated interactions convey selectivity towards oxidized substrates over their non-oxidised counterparts, in particular by stabilization of a water molecule in a hydrophobic environment through hydrogen bonding. These findings may be useful in the design of inhibitors of MTH1.     

Causes,temporal trends,and the effects of urbanization on admissions of wild raptors to rehabilitation centers in England and Wales

Data from wildlife rehabilitation centers (WRCs) can provide on‐the‐ground records of causes of raptor morbidity and mortality, allowing threat patterns to be explored throughout time and space. We provide an overview of native raptor admissions to four WRCs in England and Wales, quantifying the main causes of morbidity and mortality, trends over time, and associations between threats and urbanization between 2001 and 2019. Throughout the study period, 14 raptor species were admitted totalling 3305 admission records. The Common Buzzard (Buteo buteo; 31%) and Tawny Owl (Strix aluco; 29%) were most numerous. Relative to the proportion of breeding individuals in Britain and Ireland, Peregrine Falcons (Falco peregrinus), Little Owls (Athene noctua), and Western Barn Owls (Tyto alba) were over‐represented in the admissions data by 103%, 73%, and 69%, respectively. Contrastingly Northern Long‐eared Owls (Asio otus), Western Marsh Harriers (Circus aeruginosus), and Merlin (Falco columbarius) were under‐represented by 187%, 163%, and 126%, respectively. Across all species, vehicle collisions were the most frequent anthropogenic admission cause (22%), and orphaned young birds (10%) were most frequent natural cause. Mortality rate was highest for infection/parasite admissions (90%), whereas orphaned birds experienced lowest mortality rates (16%). For one WRC, there was a decline in admissions over the study period. Red Kite (Milvus milvus) admissions increased over time, whereas Common Buzzard and Common Kestrel admissions declined. There were significant declines in the relative proportion of persecution and metabolic admissions and an increase in orphaned birds. Urban areas were positively associated with persecution, building collisions, and unknown trauma admissions, whereas vehicle collisions were associated with more rural areas. Many threats persist for raptors in England and Wales, however, have not changed substantially over the past two decades. Threats associated with urban areas, such as building collisions, may increase over time in line with human population growth and subsequent urban expansion.     

Endothelium-derived reactive oxygen species and endothelin-1 attenuate NO-dependent pulmonary vasodilation following chronic hypoxia

Vasodilatory responses to exogenous nitric oxide (NO) are diminished following exposure to chronic hypoxia (CH) in isolated, perfused rat lungs. We hypothesized that both endothelium-derived reactive oxygen species (ROS) and endothelin-1 (ET-1) mediate this attenuated NO-dependent pulmonary vasodilation following CH. To test this hypothesis, we examined vasodilatory and vascular smooth muscle (VSM) Ca2+ responses to the NO donor spermine NONOate in UTP-constricted, isolated pressurized small pulmonary arteries from control and CH rats. Consistent with our previous findings in perfused lungs, we observed attenuated NO-dependent vasodilation following CH in endothelium-intact vessels. However, in endothelium-denuded vessels, responses to spermine NONOate were augmented in CH rats compared with controls, thus demonstrating an inhibitory influence of the endothelium on NO-dependent reactivity following CH. Whereas both the ROS scavenger tiron and the ETA receptor antagonist BQ-123 augmented NO-dependent reactivity in endothelium-intact vessels from CH rats, neither fully restored vasodilatory responses to those observed following endothelium denudation in vessels from CH rats. In contrast, the combination of tiron and BQ-123 or the nonselective ET receptor antagonist PD-145065 enhanced NO responsiveness in endothelium-intact vessels from CH rats similar to that observed following endothelium denudation. We conclude that both endothelium-derived ROS and ET-1 attenuate NO-dependent pulmonary vasodilation following CH. Furthermore, CH augments pulmonary VSM reactivity to NO.