Three years of duration-controlled grazing: What have we found?

fals

Tracking the seasonal calcification of Cyprideis torosa (Crustacea, Ostracoda) using Mg/Ca-inferred temperatures, and its implications for palaeotemperature reconstruction

Ostracod shell chemistry data are widely used for palaeoenvironmental reconstruction. Despite this, there has been little systematic research into the implications of the timing of calcification or the duration of each moult stage. Consequently, it is unclear whether palaeoenvironmental reconstructions are recording restricted (inter-seasonal) time periods or reflect the mean annual conditions. The seasonality of shell formation can therefore have implications for palaeoenvironmental reconstructions based on geochemical signatures, especially palaeotemperature, particularly in environments that show large inter-annual variations in water conditions. Cyprideis torosa is a geographically widespread and eurytopic species that has great potential for a range of palaeoenvironmental reconstructions, but inhabits environments with large seasonal and inter-annual variation. Using hourly water and air temperature data, ostracod shell and surface water chemistry from a shallow coastal pond in SE UK, we improve knowledge of the timing of Cyprideis torosa calcification, and thus our understanding of the potential seasonality of signals in palaeotemperature datasets. We suggest seasonal calcification in spring and autumn, with persistence at the adult life stage for up to 12-18 months. Sr/Ca values of C. torosa appear to reflect a Sr/Cawater control on calcification timing and have no temperature dependence. For Mg/Ca, we show a minimum temperature control on calcification of 7 ˚C, with C. torosa Mg/Ca-inferred temperatures broadly tracking spring and autumn temperatures

Role of the lipid bilayer in outer membrane protein folding in Gram negative bacteria

β-barrel outer membrane proteins (OMPs) represent the major proteinaceous component of the outer membrane (OM) of Gram-negative bacteria. These proteins perform key roles in cell structure and morphology, nutrient acquisition, colonisation and invasion, and protection against external toxic threats such as antibiotics. To become functional, OMPs must fold and insert into a crowded and asymmetric OM that lacks much freely accessible lipid. This feat is accomplished in the absence of an external energy source and is thought to be driven by the high thermodynamic stability of folded OMPs in the OM. With such a stable fold, the challenge that bacteria face in assembling OMPs into the OM is how to overcome the initial energy barrier of membrane insertion. In this review, we highlight the roles of the lipid environment and the OM in modulating the OMP folding landscape and discuss the factors that guide folding in vitro and in vivo. We particularly focus on the composition, architecture and physical properties of the OM and how an understanding of the folding properties of OMPs in vitro can help explain the challenges they encounter during folding in vivo. Current models of OMP biogenesis in the cellular environment are still in flux, but the stakes for improving the accuracy of these models are high. Since OMP folding is an essential process in all Gram-negative bacteria, and considering the looming crisis of widespread microbial drug resistance, to bring down the powerful, OMP-supported barrier against antibiotics, we must first understand how bacterial cells build it

Cyprideis torosa (Jones, 1850) in its type area and stratigraphical context: potential for mapping the freshwater/estuarine boundaries of the Thames-Medway river system in the MIS 9 and MIS 11 interglacials

GB’s contribution was supported by a Queen Mary University of London PhD studentship

Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods

The bivalved crustacean ostracods have the richest fossil record of any arthropod group and display complex reproductive strategies contributing to their evolutionary success. Sexual reproduction involving giant sperm, shared by three superfamilies of living ostracod crustaceans, is among the most fascinating behaviours. However, the origin and evolution of this reproductive mechanism has remained largely unexplored because fossil preservation of such features is extremely rare. Here, we report exceptionally preserved ostracods with soft parts (appendages and reproductive organs) in a single piece of mid-Cretaceous Kachin amber (approximately 100 Myr old). The ostracod assemblage is composed of 39 individuals. Thirty-one individuals belong to a new species and genus, Myanmarcypris hui gen. et sp. nov., exhibiting an ontogenetic sequence from juveniles to adults (male and female). Seven individuals are assigned to Thalassocypria sp. (Cypridoidea, Candonidae, Paracypridinae) and one to Sanyuania sp. (Cytheroidea, Loxoconchidae). Our micro-CT reconstruction provides direct evidence of the male clasper, sperm pumps (Zenker organs), hemipenes, eggs and female seminal receptacles with giant sperm. Our results reveal that the reproduction behavioural repertoire, which is associated with considerable morphological adaptations, has remained unchanged over at least 100 million years—a paramount example of evolutionary stasis. These results also double the age of the oldest unequivocal fossil animal sperm. This discovery highlights the capacity of amber to document invertebrate soft parts that are rarely recorded by other depositional environments

Crustacean remains from the Yuka mammoth raise questions about non-analogue freshwater communities in the Beringian region during the Pleistocene

This work is licensed under a Creative Commons Attribution 4.0 International License.Frozen permafrost Pleistocene mammal carcasses with soft tissue remains are subject to intensive study and help elucidate the palaeoenvironment where these animals lived. Here we present an inventory of the freshwater fauna and flora found in a sediment sample from the mummified Woolly Mammoth carcass found in August 2010, from the Oyogos Yar coast near the Kondratievo River in the Laptev Sea region, Sakha (Yakutia) Republic, NE Russia. Our study demonstrates that the waterbody where the carcass was buried could be characterized as a shallow pond or lake inhabited mainly by taxa which are present in this area today, but additionally by some branchiopod crustacean taxa currently absent or unusual in the region although they exist in the arid zone of Eurasia (steppes and semi-deserts). These findings suggest that some “non-analogue” crustacean communities co-existed with the “Mammoth fauna”. Our findings raise questions about the nature of the waterbodies that existed in Beringia during the MIS3 climatic optimum when the mammoth was alive

Laparoscopic treatment of isolated superficial peritoneal endometriosis for managing chronic pelvic pain in women:study protocol for a randomised controlled feasibility trial (ESPriT1)

Background: Endometriosis (where endometrial-like tissue is found outside the uterus) affects ~ 176 million women worldwide and can lead to debilitating pelvic pain. Three subtypes of endometriosis exist, with ~ 80% of women having superficial peritoneal endometriosis (SPE). Endometriosis is diagnosed by laparoscopy and, if SPE is found, gynaecologists usually remove it surgically. However, many women get limited pain relief from surgical removal of SPE. We plan to undertake a future large trial where women who have only SPE found at initial laparoscopy are randomly allocated to have surgical removal (excision or ablation) of SPE, or not. Ultimately, we want to determine whether surgical removal improves overall symptoms and quality of life, or whether surgery is of no benefit, exacerbates symptoms, or even causes harm. The primary objective of this feasibility study is to determine what proportion of women with suspected SPE undergoing diagnostic laparoscopy will agree to randomisation. The secondary objectives are to determine if there are differences in key prognostic parameters between eligible women that agree to be randomised and those that decline; how many women having laparoscopy for investigation of chronic pelvic pain are eligible for the trial; the range of treatment effects and variability in outcomes and the most acceptable methods of recruitment, randomisation and assessment tools. Methods: We will recruit up to 90 women with suspected SPE undergoing diagnostic laparoscopy over a 9-month recruitment period in four Scottish hospitals and randomise them 1:1 to either diagnostic laparoscopy alone (with a sham port to achieve blinding of the allocation) or surgical removal of endometriosis. Baseline characteristics, e.g. age, index of social deprivation, ethnicity, and intensity/duration of pain will be collected. Participants will be followed up by online questionnaires assessing pain, physical and emotional function at baseline, 3 months, 6 months and 12 months. Discussion: Recruitment to a randomised controlled trial to assess the effectiveness of surgery for endometriosis may be challenging because of preconceived ideas about treatment success amongst patients and clinicians. We have designed this study to assess feasibility of recruitment and to inform the design of our future definitive trial. Trial registration: ClincicalTrials.gov, NCT04081532 Status: Recruiting

Holocene paleoecology and paleoceanography of the southwestern Black Sea shelf revealed by ostracod assemblages

The Holocene replacement of Ponto-Caspian ostracod assemblages by Mediterranean species is studied in two long composite cores, M02-45 (a composite of cores M02-45P, M02-45 T and M05-03P) and M05-50 (a composite of cores M05-50P and M05-51G), acquired at sites −69 m and −91 m deep on the southwestern Black Sea shelf. Composite core M02-45 was collected from the middle shelf and composite core M05-50 was acquired on the distal fringe of the eastern levée of a saline underflow channel emanating from the Strait of Bosphorus. Sixteen radiocarbon dates in M02-45 and nine in M05-50 are used to construct age models, which show recovery of sediments as old as 12,915 cal yr BP (M02-45 site) and 12,010 cal yr BP (M05-50 site). A total of 45 ostracod species are identified in the two cores. From ~12,000 to ~7425 cal yr BP, the ostracod assemblage is dominated by Ponto-Caspian species, mainly Loxoconcha sublepida, L. lepida and Tyrrhenocythere amnicola donetziensis. From ~7425 to ~6315 cal yr BP the assemblage consists of nearly equal abundances of Mediterranean species (Cytheroma variabilis in M02-45; Sagmatocythere littoralis in M05-50) and the Ponto-Caspian species. After ~6315 cal yr BP to the tops of the cores, the assemblage is dominated by Mediterranean species, including Palmoconcha agilis, Carinocythereis carinata, Hiltermannicythere rubra and Pterygocythereis jonesii. Cluster analysis further subdivides the stratigraphic succession into six bioecozones with different ostracod assemblages. The changes in the ostracod assemblages from one bioecozone to the next indicate that progressive environmental changes took place on the southwestern Black Sea shelf from at least 7500 cal yr BP to the present. The first hint of changing conditions at ~7500 cal yr BP lags the initial reconnection to the Mediterranean Sea through the Strait of Bosphorus by ~2000 yr, demonstrating that Black Sea salinity increased slowly and took that long to reach values tolerable to marine ostracod immigrants. Widespread colonization by Mediterranean species took even longer, ~3000 years from the time of the initial reconnection

Rapid Late Pleistocene climate change reconstructed from a lacustrine ostracod record in central Italy (Lake Trasimeno, Umbria)

© 2020 Collegium Boreas. Published by John Wiley & Sons Ltd This study presents, for the first time, a detailed quantitative reconstruction of winter (January) and summer (July) palaeotemperatures from the Late Pleistocene to Holocene transition in central Italy based on ostracod assemblages in an 8.59-m-long sediment core retrieved in Lake Trasimeno. Of 19 ostracod species recovered, 13 were calibrated according to their living temperature ranges, enabling us to reconstruct mean January and July temperature ranges using the mutual ostracod temperature range (MOTR) method. The occurrences of Cytheromorpha fuscata and Limnocythere suessenbornensis from 44 000 to 25 500 cal. a BP showed mean January temperatures at least 7 °C colder and mean July temperature at least 1 °C cooler in some intervals compared to present-day temperatures. Comparison of the MOTR-derived January minima curve with a Greenland oxygen isotope record (NGRIP) shows a remarkable correlation of warmer Greenland Interstadial and the colder Greenland Stadial events with clear peaks and troughs in the MOTR signal. These correlations were tested successfully by tuning the MOTR curve to the NGRIP record, resulting in an improved age-depth model combining radiocarbon ages with MOTR tie points. The results demonstrate that a record of rapid climate change in the North Atlantic region is archived in lacustrine ostracod assemblages in central Italy