Progress and Challenges in Ocean Metaproteomics and Proposed Best Practices for Data Sharing.

Ocean metaproteomics is an emerging field enabling discoveries about marine microbial communities and their impact on global biogeochemical processes. Recent ocean metaproteomic studies have provided insight into microbial nutrient transport, colimitation of carbon fixation, the metabolism of microbial biofilms, and dynamics of carbon flux in marine ecosystems. Future methodological developments could provide new capabilities such as characterizing long-term ecosystem changes, biogeochemical reaction rates, and in situ stoichiometries. Yet challenges remain for ocean metaproteomics due to the great biological diversity that produces highly complex mass spectra, as well as the difficulty in obtaining and working with environmental samples. This review summarizes the progress and challenges facing ocean metaproteomic scientists and proposes best practices for data sharing of ocean metaproteomic data sets, including the data types and metadata needed to enable intercomparisons of protein distributions and annotations that could foster global ocean metaproteomic capabilities.

Metronomic administration of lomustine following palliative radiation therapy for appendicular osteosarcoma in dogs.

The purpose of this study was to determine if metronomic administration of lomustine following palliative radiation therapy (RT) improved length of palliation and therefore survival in dogs with appendicular osteosarcoma compared to treatment with palliative radiation alone. A search of medical records identified dogs with appendicular osteosarcoma, treated with palliative RT (2 fractions of 8 Gray in a 24 hour time frame, day 0 and day 1; or day 0, 6 hours apart). Data collected included signalment, history, clinical signs, physical examination findings, clinicopathologic abnormalities, extent of disease, response, toxicity, other therapy, survival time, and whether dogs received metronomic lomustine (ML) or not. Of 86 patients, 43 received ML while 43 did not. Median survival time (MST) was not significantly different (P = 0.84), at 184 +/- 17 days for patients which received ML, and 154 +/- 20 days for those which did not. Metronomic lomustine administration was well-tolerated, but it did not improve survival in dogs with palliatively treated osteosarcoma.

Administration métronomique de lomustine après radiothérapie palliative pour le traitement des ostéosarcomes appendiculaires chez le chien. L'objectif de cette étude était de déterminer si l'administration métronomique de lomustine après radiothérapie palliative (RT) améliore la durée de palliation, et par conséquent la durée de vie, des chiens atteints d'ostéosarcome appendiculaire, en comparaison avec la radiothérapie seule. Les dossiers médicaux des chiens atteints d'ostéosarcome appendiculaire traités par radiothérapie palliative (2 fractions de 8 Gray dans un intervalle de 24 heures, jour 0 et jour 1; ou jour 0, à 6 heures d'intervalle) ont été identifiés et évalués. Les données collectées incluaient l'anamnèse, les commémoratifs, les anomalies de l'examen clinique et des analyses de laboratoires, les résultats du bilan d'extension, la réponse au(x) traitement(s), le développement de toxicités, d'éventuelles autres thérapies prodiguées, la durée de vie et si les chiens avaient été traités avec de la lomustine ou non. Sur 86 patients, 43 ont reçu de la lomustine tandis que 43 n'en ont pas reçu. La médiane de survie (MST) n'était pas significativement différente (P = 0.84), 184 +/− 17 jours pour les patients traités avec de la lomustine, et 154 +/− 20 jours pour ceux n'ayant pas reçu de lomustine. L'administration métronomique de lomustine était bien tolérée mais ne prodigua pas d'amélioration de la durée de vie lors de la prise en charge palliative des chiens atteints d'ostéosarcome.(Traduit par les auteurs).

Copper, zinc and calcium: imaging and quantification in anterior pituitary secretory granules.

The anterior pituitary is specialized for the synthesis, storage and release of peptide hormones. The activation of inactive peptide hormone precursors requires a specific set of proteases and other post-translational processing enzymes. High levels of peptidylglycine α-amidating monooxygenase (PAM), an essential peptide processing enzyme, occur in the anterior pituitary. PAM, which converts glycine-extended peptides into amidated products, requires copper and zinc to support its two catalytic activities and calcium for structure. We used X-ray fluorescence microscopy on rat pituitary sections and inductively coupled plasma mass spectrometry on subcellular fractions prepared from rat anterior pituitary to localize and quantify copper, zinc and calcium. X-ray fluorescence microscopy indicated that the calcium concentration in pituitary tissue was about 2.5 mM, 10-times more than zinc and 50-times more than copper. Although no higher than cytosolic levels, secretory granule levels of copper exceeded PAM levels by a factor of 10. Atp7a, which transports copper into the lumen of the secretory pathway, was enriched in endosomes and Golgi, not in secretory granules. If Atp7a transfers copper directly to PAM, this pH-dependent process is likely to occur in Golgi and endosomes.

Adaptor Protein-1 Complex Affects the Endocytic Trafficking and Function of Peptidylglycine α-Amidating Monooxygenase, a Luminal Cuproenzyme.

The adaptor protein-1 complex (AP-1), which transports cargo between the trans-Golgi network and endosomes, plays a role in the trafficking of Atp7a, a copper-transporting P-type ATPase, and peptidylglycine α-amidating monooxygenase (PAM), a copper-dependent membrane enzyme. Lack of any of the four AP-1 subunits impairs function, and patients with MEDNIK syndrome, a rare genetic disorder caused by lack of expression of the σ1A subunit, exhibit clinical and biochemical signs of impaired copper homeostasis. To explore the role of AP-1 in copper homeostasis in neuroendocrine cells, we used corticotrope tumor cells in which AP-1 function was diminished by reducing expression of its µ1A subunit. Copper levels were unchanged when AP-1 function was impaired, but cellular levels of Atp7a declined slightly. The ability of PAM to function was assessed by monitoring 18-kDa fragment-NH2 production from proopiomelanocortin. Reduced AP-1 function made 18-kDa fragment amidation more sensitive to inhibition by bathocuproine disulfonate, a cell-impermeant Cu(I) chelator. The endocytic trafficking of PAM was altered, and PAM-1 accumulated on the cell surface when AP-1 levels were reduced. Reduced AP-1 function increased the Atp7a presence in early/recycling endosomes but did not alter the ability of copper to stimulate its appearance on the plasma membrane. Co-immunoprecipitation of a small fraction of PAM and Atp7a supports the suggestion that copper can be transferred directly from Atp7a to PAM, a process that can occur only when both proteins are present in the same subcellular compartment. Altered luminal cuproenzyme function may contribute to deficits observed when the AP-1 function is compromised.