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6 results on '"Konieczka, S"'

1. Hiding in the background: community-level patterns in invertebrate herbivory across the tundra biome

Author

Rheubottom, SI, Barrio, IC, Kozlov, MV, Alatalo, JM, Andersson, T, Asmus, AL, Baubin, C, Brearley, FQ, Egelkraut, DD, Ehrich, D, Gauthier, G, Jónsdóttir, IS, Konieczka, S, Lévesque, E, Olofsson, J, Prevéy, JS, Slevan-Tremblay, G, Sokolov, A, Sokolova, N, Sokovnina, S, Speed, JDM, Suominen, O, Zverev, V, Hik, DS, Rheubottom, SI, Barrio, IC, Kozlov, MV, Alatalo, JM, Andersson, T, Asmus, AL, Baubin, C, Brearley, FQ, Egelkraut, DD, Ehrich, D, Gauthier, G, Jónsdóttir, IS, Konieczka, S, Lévesque, E, Olofsson, J, Prevéy, JS, Slevan-Tremblay, G, Sokolov, A, Sokolova, N, Sokovnina, S, Speed, JDM, Suominen, O, Zverev, V, and Hik, DS

Abstract

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Invertebrate herbivores depend on external temperature for growth and metabolism. Continued warming in tundra ecosystems is proposed to result in increased invertebrate herbivory. However, empirical data about how current levels of invertebrate herbivory vary across the Arctic is limited and generally restricted to a single host plant or a small group of species, so predicting future change remains challenging. We investigated large-scale patterns of invertebrate herbivory across the tundra biome at the community level and explored how these patterns are related to long-term climatic conditions and year-of-sampling weather, habitat characteristics, and aboveground biomass production. Utilizing a standardized protocol, we collected samples from 92 plots nested within 20 tundra sites during summer 2015. We estimated the community-weighted biomass lost based on the total leaf area consumed by invertebrates for the most common plant species within each plot. Overall, invertebrate herbivory was prevalent at low intensities across the tundra, with estimates averaging 0.94% and ranging between 0.02 and 5.69% of plant biomass. Our results suggest that mid-summer temperature influences the intensity of invertebrate herbivory at the community level, consistent with the hypothesis that climate warming should increase plant losses to invertebrates in the tundra. However, most of the observed variation in herbivory was associated with other site level characteristics, indicating that other local ecological factors also play an important role. More details about the local drivers of invertebrate herbivory are necessary to predict the consequences for rapidly changing tundra ecosystems.

Published
2019

5. Dicer1-miR-328-Bace1 signalling controls brown adipose tissue differentiation and function.

Author

Oliverio M, Schmidt E, Mauer J, Baitzel C, Hansmeier N, Khani S, Konieczka S, Pradas-Juni M, Brodesser S, Van TM, Bartsch D, Brönneke HS, Heine M, Hilpert H, Tarcitano E, Garinis GA, Frommolt P, Heeren J, Mori MA, Brüning JC, and Kornfeld JW

Subjects
Amyloid Precursor Protein Secretases metabolism, Animals, Aspartic Acid Endopeptidases metabolism, DEAD-box RNA Helicases metabolism, Energy Metabolism physiology, Homeostasis physiology, Insulin Resistance physiology, Mice, Inbred C57BL, MicroRNAs metabolism, Obesity genetics, Obesity metabolism, Ribonuclease III metabolism, Adipose Tissue, Brown metabolism, Amyloid Precursor Protein Secretases genetics, Aspartic Acid Endopeptidases genetics, Cell Differentiation physiology, DEAD-box RNA Helicases genetics, MicroRNAs genetics, Ribonuclease III genetics
Abstract

Activation of brown adipose tissue (BAT) controls energy homeostasis in rodents and humans and has emerged as an innovative strategy for the treatment of obesity and type 2 diabetes mellitus. Here we show that ageing- and obesity-associated dysfunction of brown fat coincides with global microRNA downregulation due to reduced expression of the microRNA-processing node Dicer1. Consequently, heterozygosity of Dicer1 in BAT aggravated diet-induced-obesity (DIO)-evoked deterioration of glucose metabolism. Analyses of differential microRNA expression during preadipocyte commitment and mouse models of progeria, longevity and DIO identified miR-328 as a regulator of BAT differentiation. Reducing miR-328 blocked preadipocyte commitment, whereas miR-328 overexpression instigated BAT differentiation and impaired muscle progenitor commitment-partly through silencing of the β-secretase Bace1. Loss of Bace1 enhanced brown preadipocyte specification in vitro and was overexpressed in BAT of obese and progeroid mice. In vivo Bace1 inhibition delayed DIO-induced weight gain and improved glucose tolerance and insulin sensitivity. These experiments reveal Dicer1-miR-328-Bace1 signalling as a determinant of BAT function, and highlight the potential of Bace1 inhibition as a therapeutic approach to improve not only neurodegenerative diseases but also ageing- and obesity-associated impairments of BAT function.

Published
2016
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6. Strain and force transducers used in human and veterinary tendon and ligament biomechanical studies.

Author

Ravary B, Pourcelot P, Bortolussi C, Konieczka S, and Crevier-Denoix N

Subjects
Animals, Elasticity, Equipment Design, Equipment Failure Analysis, Humans, Ligaments surgery, Stress, Mechanical, Tendons surgery, Biomechanical Phenomena instrumentation, Ligaments physiology, Prostheses and Implants, Tendons physiology, Transducers
Abstract

Biomechanical studies often aim at determining the contribution (in terms of load or strain) of a tendon or ligament in posture, gesture or locomotion. To this end, many transducers have been developed since 30 years. These devices implanted within or attached to the inside of the tendon or ligament must be compliant enough to measure in vivo the tissue load or strain without interfering with the movement of man or animals. They can be transducers with variation of electrical resistance (liquid metal strain gauge, buckle transducer, implantable force transducer and pressure transducer), variation of magnetic field (Hall effect transducer) and variation of light flow (optic fibre). Their use requires surgery in order to implant them and it is limited in time because of their invasive character and the development of fibrous healing reactions. Besides, the transducer dimensions and its position in the tendon can influence the transducer output signal. Moreover, the latter may not reflect the behaviour of the tendon as a whole but only locally. In addition, a calibration is required in order to convert the output signal into a strain or a force. In animals, this calibration is generally made by a post-mortem procedure on dissected anatomical specimens; in man, an indirect calibration procedure using inverse dynamic calculations is generally performed. However, the calibration conditions cannot reproduce exactly the in vivo conditions. So far, only invasive transducers have allowed to measure strain or force in tendons with all constraints and limits mentioned above., (Copyright 2004 Elsevier Ltd.)

Published
2004
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