Warm temperatures, cool sponges: the effect of increased temperatures on the Antarctic sponge Isodictya sp.

Although the cellular and molecular responses to exposure to relatively high temperatures (acute thermal stress or heat shock) have been studied previously, only sparse empirical evidence of how it affects cold-water species is available. As climate change becomes more pronounced in areas such as the Western Antarctic Peninsula, both long-term and occasional acute temperature rises will impact species found there, and it has become crucial to understand the capacity of these species to respond to such thermal stress. Here, we use the Antarctic sponge Isodictya sp. to investigate how sessile organisms (particularly Porifera) can adjust to acute short-term heat stress, by exposing this species to 3 and 5 °C for 4 h, corresponding to predicted temperatures under high-end 2080 IPCC-SRES scenarios. Assembling a de novo reference transcriptome (90,188 contigs, >93.7% metazoan BUSCO genes) we have begun to discern the molecular response employed by Isodictya to adjust to heat exposure. Our initial analyses suggest that TGF-β, ubiquitin and hedgehog cascades are involved, alongside other genes. However, the degree and type of response changed little from 3 to 5 °C in the time frame examined, suggesting that even moderate rises in temperature could cause stress at the limits of this organism’s capacity. Given the importance of sponges to Antarctic ecosystems, our findings are vital for discerning the consequences of short-term increases in Antarctic ocean temperature on these and other species.

Download Full-text

Warm Temperatures, Cool Sponges: The Effect of Increased Temperatures on the Antarctic Sponge Isodictya sp

10.1101/416677 ◽

2018 ◽

Author(s):

M. González-Aravena ◽

N.J. Kenny ◽

M. Osorio ◽

A. Font ◽

A. Riesgo ◽

...

Keyword(s):

Thermal Stress ◽

De Novo ◽

Cold Water ◽

Western Antarctic Peninsula ◽

Sres Scenarios ◽

Ipcc Sres ◽

The Antarctic ◽

Sessile Organisms ◽

Water Species ◽

Cold Water Species

AbstractAlthough the cellular and molecular responses to exposure to relatively high temperatures (acute thermal stress or heat shock) have been studied previously, only sparse empirical evidence of how it affects cold-water species is available. As climate change becomes more pronounced in areas such as the Western Antarctic Peninsula, it has become crucial to understand the capacity of these species to respond to thermal stress.Here we use the Antarctic sponge Isodictya sp. to investigate how sessile organisms (particularly Porifera) can adjust to acute short-term heat stress, by exposing this species to 3 and 5 °C for 4 hours, corresponding to predicted temperatures under high-end 2080 IPCC-SRES scenarios. Assembling a de novo reference transcriptome (90,188 contigs, >93.7% metazoan BUSCO genes) we have begun to discern the molecular componentry employed by Isodictya to adjust to environmental insult.Our initial analyses suggest that TGF-β, ubiquitin and hedgehog cascades are involved, alongside other genes. However, the degree and type of response changed little from 3 to 5 °C, suggesting that even moderate rises in temperature could cause stress at the limits of this organism’s capacity. Given the importance of sponges to Antarctic ecosystems, our findings are vital for discerning the consequences of increases in Antarctic ocean temperature on these and other species.

Download Full-text

Salinity effects on cultured Neogloboquadrina pachyderma (sinistral) from high latitudes: new paleoenvironmental insights

Geo-Marine Letters ◽

10.1007/s00367-020-00677-1 ◽

2021 ◽

Vol 41 (1) ◽

Author(s):

Jacqueline Bertlich ◽

Nikolaus Gussone ◽

Jasper Berndt ◽

Heinrich F. Arlinghaus ◽

Gerhard S. Dieckmann

Keyword(s):

Sea Ice ◽

Cold Water ◽

Weddell Sea ◽

Wall Thickening ◽

High Latitudes ◽

Neogloboquadrina Pachyderma ◽

Antarctic Sea Ice ◽

The Antarctic ◽

Water Species ◽

Cold Water Species

AbstractThis study presents culture experiments of the cold water species Neogloboquadrina pachyderma (sinistral) and provides new insights into the incorporation of elements in foraminiferal calcite of common and newly established proxies for paleoenvironmental applications (shell Mg/Ca, Sr/Ca and Na/Ca). Specimens were collected from sea ice during the austral winter in the Antarctic Weddell Sea and subsequently cultured at different salinities and a constant temperature. Incorporation of the fluorescent dye calcein showed new chamber formation in the culture at salinities of 30, 31, and 69. Cultured foraminifers at salinities of 46 to 83 only revealed chamber wall thickening, indicated by the fluorescence of the whole shell. Signs of reproduction and the associated gametogenic calcite were not observed in any of the culture experiments. Trace element analyses were performed using an electron microprobe, which revealed increased shell Mg/Ca, Sr/Ca, and Na/Ca values at higher salinities, with Mg/Ca showing the lowest sensitivity to salinity changes. This study enhances the knowledge about unusually high element concentrations in foraminifera shells from high latitudes. Neogloboquadrina pachyderma appears to be able to calcify in the Antarctic sea ice within brine channels, which have low temperatures and exceptionally high salinities due to ongoing sea ice formation.

Download Full-text

Polylactide-based stent coatings: biodegradable polymeric coatings capable of maintaining sustained release of the thrombolytic enzyme streptokinase

Pure and Applied Chemistry ◽

10.1515/pac-2019-1101 ◽

2020 ◽

Vol 92 (8) ◽

pp. 1329-1340

Author(s):

A. G. Kolmakov ◽

A. S. Baikin ◽

S. V. Gudkov ◽

K. N. Belosludtsev ◽

E. O. Nasakina ◽

...

Keyword(s):

Mechanical Properties ◽

Polymer Films ◽

De Novo ◽

Membrane Surface ◽

Aqueous Media ◽

Polymeric Coatings ◽

Short Term ◽

Thrombolytic Activity ◽

Viable Cells ◽

Nitinol Stents

AbstractThe paper describes synthesis and testing of novel biodegradable polylactide-based polymer membranes with desired mechanical properties, which are capable of sustained and directed release of biomacromolecules with high molecular weight (in particular, streptokinase; m.w. 47 kDa). Streptokinase is a pharmaceutical agent, possessing a pronounced thrombolytic activity. The membranes synthesized had a percentage elongation of 2–11% and tensile strength of 25–85 MPa. They were biodegradable – yet being stored in aqueous media in the absence of biological objects, would be dissolved by no more than 10% in 6 months. The synthesized membranes were capable of controlled release of streptokinase into the intercellular space, with the enzyme retaining more than 90% of its initial activity. The rate of streptokinase release from the membranes varied from 0.01 to 0.04 mg/day per cm2 of membrane surface. The membrane samples tested in the work did not have any short-term toxic effects on the cells growing de novo on the membrane surface. The mitotic index of those cells was approximately 1.5%, and the number of non-viable cells on the surface of the polymer films did not exceed 3–4% of their total amount. The implantation of the synthesized polymers – as both individual films and coatings of nitinol stents – was not accompanied by any postoperative complications. The subsequent histological examination revealed no abnormalities. Two months after the implantation of polymer films, only traces of polylactide were found in the implant-surrounding tissues. The implantation of stents coated with streptokinase-containing polymers resulted in the formation of a mature and thick connective-tissue capsules. Thus, the polylactide membranes synthesized and tested in this work are biodegradable, possess the necessary mechanical properties and are capable of sustained and directed release of streptokinase macromolecules.

Download Full-text

Discovery of novel chemical reactions by deep generative recurrent neural network

Scientific Reports ◽

10.1038/s41598-021-81889-y ◽

2021 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

William Bort ◽

Igor I. Baskin ◽

Timur Gimadiev ◽

Artem Mukanov ◽

Ramil Nugmanov ◽

...

Keyword(s):

Chemical Reactions ◽

Short Term Memory ◽

De Novo ◽

Molecular Structures ◽

Topographic Map ◽

Short Term ◽

Suzuki Reactions ◽

Class A ◽

Latent Space ◽

Long Short Term Memory

AbstractThe “creativity” of Artificial Intelligence (AI) in terms of generating de novo molecular structures opened a novel paradigm in compound design, weaknesses (stability & feasibility issues of such structures) notwithstanding. Here we show that “creative” AI may be as successfully taught to enumerate novel chemical reactions that are stoichiometrically coherent. Furthermore, when coupled to reaction space cartography, de novo reaction design may be focused on the desired reaction class. A sequence-to-sequence autoencoder with bidirectional Long Short-Term Memory layers was trained on on-purpose developed “SMILES/CGR” strings, encoding reactions of the USPTO database. The autoencoder latent space was visualized on a generative topographic map. Novel latent space points were sampled around a map area populated by Suzuki reactions and decoded to corresponding reactions. These can be critically analyzed by the expert, cleaned of irrelevant functional groups and eventually experimentally attempted, herewith enlarging the synthetic purpose of popular synthetic pathways.

Download Full-text

De novo assembly of the transcriptome of scleractinian coral, Anomastraea irregularis and analyses of its response to thermal stress

Molecular Biology Reports ◽

10.1007/s11033-021-06184-5 ◽

2021 ◽

Author(s):

Christine A. Onyango ◽

David Glassom ◽

Angus MacDonald

Keyword(s):

Thermal Stress ◽

De Novo Assembly ◽

Scleractinian Coral ◽

De Novo

Download Full-text

“Logrolling” in Antarctic governance: Limits and opportunities

Polar Record ◽

10.1017/s003224742000039x ◽

2020 ◽

Vol 56 ◽

Author(s):

Jeffrey McGee ◽

Bruno Arpi ◽

Andrew Jackson

Keyword(s):

Marine Protected Areas ◽

International Institutions ◽

Marine Resources ◽

International Governance ◽

Short Term ◽

Current Case ◽

Antarctic Marine ◽

Antarctic Treaty ◽

Kunlun Station ◽

The Antarctic

Abstract The Antarctic Treaty System (ATS) is considered a successful example of international governance as it has managed tensions over sovereignty claims, avoided militarisation and dealt with marine resources and environmental protection. Recently, China’s influence and assertiveness in many international institutions have significantly grown. What effect this shift in the international politics will have upon Antarctic governance remains to be seen. However, to further thinking on this issue we explore two current case studies that reveal pressure points within the ATS. First, in the Commission for the Conservation of Antarctic Marine Living Resources, Australia has proposed marine protected areas off East Antarctica, to which China and several other states have objected. Second, in the Antarctic Treaty Consultative Meetings, China has proposed special management arrangements for the area around the “Kunlun” station, to which Australia and several other states have objected. Negotiation theory suggests “logrolling” (i.e. trade of mutual decision-making support across issue areas) can be an effective strategy to avoid diplomatic deadlocks. We therefore consider the merits of a logrolling strategy for the above issues. We find that while a logrolling strategy in the ATS might facilitate short-term diplomatic success, it would carry significant risks, including the weakening of existing norms.

Download Full-text

Metabolic and endocrine changes induced by chronic heatexposure in broiler chickens : biological and endocrinological variables

British Journal Of Nutrition ◽

10.1017/bjn19960125 ◽

1996 ◽

Vol 75 (2) ◽

pp. 205-216 ◽

Cited By ~ 2

Author(s):

P. A. Geraert ◽

J. C. F. Padilha ◽

S. Guillaumin

Keyword(s):

Amino Acids ◽

Ambient Temperature ◽

Broiler Chickens ◽

De Novo ◽

Heat Exposure ◽

Plasma Corticosterone ◽

Plasma Metabolites ◽

Exogenous Insulin ◽

Plasma Insulin Concentration ◽

Esterified Fatty Acids

Abstract:The present study was designed to investigate the effect of chronic heat exposure (32° constant) on plasma metabolites and hormone concentrations in broiler chickens. At 2 and 4 weeks of age, fifty-four male Shaver broiler chickens were allocated to one of three treatments: 22°ad lib. feeding (22AL), 32°ad lib. feeding (32AL) and 22°,pair-feeding with the 32AL group (22PF). Ambient temperature was kept constant at either 22 or 32° for 2 weeks. Plasma glucose, triacylglycerols, phospholipids, non-esterified fatty acids (NEFA), individual amino acids, uric acid, insulin, triiodothyronine (T3), thyroxine, corticosterone were determined. Sensitivity to exogenous insulin was also measured at 7 weeks of age. At 4 and 6 weeks of age, i.e. after 2 weeks at high ambient temperature, fasted 32AL chickens displayed similar concentrations of glucose and triacylglycerols to those of 22AL birds. When fed, 32AL chickens exhibited higher plasma levels of glucose and decreased concentrations of NEFAand amino acids. Feed restriction resulted in intermediate values. Concentrations of all plasmafree amino acids were decreased under heat exposure except for aspartic acid, glutamic acid andphenylalanine. At 6 weeks of age, plasma T3 was reduced irrespective of the nutritional state, while plasma corticosterone concentrations were increased in 32AL birds compared with 22AL birds. Heat exposure did not change plasma insulin concentration in either fasted or fed chickens. The 32AL chickens displayed significantly reduced sensitivity to exogenous insulin when fasted,but an enhanced response to insulin when fed, compared with both 22° groups. Such endocrinological changes could stimulate lipid accumulation through increasedde novolipogenesis, reduced lipolysis and enhanced amino acid catabolism under chronic heat exposure.

Download Full-text