Hasil untuk "Biology"

A. Keys, J. Brozek, A. Henschel et al.

C. Gans

P. Siegel

J. Slack

M. Sporn, A. Roberts, L. M. Wakefield et al.

W ITHIN the past two years, there has been an exponential increase in research on transforming growth factor-beta (TGF-beta). ~ In this brief minireview, we cannot provide a detailed survey of this topic (see referenees 56 and 73 for other reviews). Rather, we will summarize some new results, indicative of the importance of this peptide as a multifunetional regulator of cellular activity. The term ~nultifunetional" implies that TGF-beta may either stimulate cell proliferation and growth, or inhibit cell proliferation and growth, or have numerous other actions having little relationship to either of these two processes. We will develop the theme that many of the actions of TGF-beta are related to the response of cells or tissues to stress or injury, and to the repair of resultant damage. However, it is clear that there is no one principal action for TGF-beta; moreover, the almost universal cellular distribution of its receptor encompasses a very broad spectrum of target tissues.

L. Rubin, J. Staddon

Douglas D. Thomas, L. Ridnour, J. Isenberg et al.

J. Fredrickson, M. Romine, A. Beliaev et al.

J. Estrela, Á. Ortega, E. Obrador

J. Giovannoni

Hans F. Weinberger, Mark A. Lewis, Bingtuan Li

M. Bradl, H. Lassmann

Oligodendrocytes are the myelinating cells of the central nervous system (CNS). They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons. Due to this complex differentiation program, and due to their unique metabolism/physiology, oligodendrocytes count among the most vulnerable cells of the CNS. In this review, we first describe the different steps eventually culminating in the formation of mature oligodendrocytes and myelin sheaths, as they were revealed by studies in rodents. We will then show differences and similarities of human oligodendrocyte development. Finally, we will lay out the different pathways leading to oligodendrocyte and myelin loss in human CNS diseases, and we will reveal the different principles leading to the restoration of myelin sheaths or to a failure to do so.

Nirupa Chaudhari, S. Roper

Taste buds are aggregates of 50–100 polarized neuroepithelial cells that detect nutrients and other compounds. Combined analyses of gene expression and cellular function reveal an elegant cellular organization within the taste bud. This review discusses the functional classes of taste cells, their cell biology, and current thinking on how taste information is transmitted to the brain.

A. Larkum, R. Orth, C. Duarte

B. Palsson

R. Siddiqui, N. Khan

Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.

S. Huelga, M. Plenio

Abstract Quantum biology is an emerging field of research that concerns itself with the experimental and theoretical exploration of non-trivial quantum phenomena in biological systems. In this tutorial overview we aim to bring out fundamental assumptions and questions in the field, identify basic design principles and develop a key underlying theme – the dynamics of quantum dynamical networks in the presence of an environment and the fruitful interplay that the two may enter. At the hand of three biological phenomena whose understanding is held to require quantum mechanical processes, namely excitation and charge transfer in photosynthetic complexes, magneto-reception in birds and the olfactory sense, we demonstrate that this underlying theme encompasses them all, thus suggesting its wider relevance as an archetypical framework for quantum biology.

R. Adolphs

Jie Li, Yuhao Li, Xiaoyang Zhou et al.

Abstract Chronic inflammation in adipose tissue is widely recognized as a pivotal link connecting obesity to a spectrum of related chronic diseases, including type 2 diabetes, non-alcoholic fatty liver disease, and cardiovascular disorders. In this pathogenic process, the dysregulated interaction between adipocytes and adipose-resident immune cells plays a critical regulatory role; however, the underlying mechanisms governing this abnormal interaction remain largely unknown. In this study, we showed that upregulated β2-microglobulin expression in hypertrophic adipocytes during obesity not only mediated the activation of adipose-resident CD8+ T cells in a cell contact-dependent manner but also facilitated iron overload and the ferroptosis of adipocytes, thereby promoting the M1 polarization of adipose tissue macrophages. Conversely, specific ablation of β2-microglobulin in adipocytes effectively suppressed the activation and accumulation of adipose-resident CD8+ T cells, as well as adipocyte ferroptosis and M1 polarization, ultimately preventing high-fat diet-induced obesity and its related inflammation and metabolic disorders. Additionally, adeno-associated virus-mediated adipose-targeted knockdown of β2-microglobulin has been demonstrated to therapeutically alleviate high-fat diet-induced obesity, as well as its related chronic inflammation and metabolic disorders. Furthermore, our bioinformatic analysis of human adipose transcriptome data revealed a strong correlation between adipose β2-microglobulin and obesity. More importantly, β2-microglobulin is significantly upregulated in adipocytes isolated from patients with obesity. Thus, our findings highlight the pivotal role of adipocytes in obesity-associated chronic inflammation and metabolic disorders via β2-microglobulin-dependent mechanisms.

Jens‐Peter Barnekow Lillesø, Davide Barsotti, James Kalema et al.

Abstract Forest and landscape restoration are increasingly popular nature‐based solutions to mitigate climate change and safeguard biodiversity. Restoration planning and monitoring implies that a reference ecosystem has been defined to which the restored site can be compared, but how to best select such reference? We tested three different potential natural vegetation (PNV) maps of the same areas in Kenya and Uganda for their utility as ecological references with independent data that were not used when those maps were made. These independent datasets included presence observations of woody species from 76 sites in forest reserves in Kenya and Uganda, and classification of surveyed species into a system that included “forest‐only” and “nonforest‐only” ecological types. Our tests show that (1) the three vegetation maps largely agree on the environmental envelopes/ranges within which forests occur. (2) There are large differences in how well the maps predict the presence of forest‐only species. (3) Two maps, based on empirical observations (V4A and White), predict forest types well, whereas the third, based on climate envelopes only (NS), performs poorly. (4) A large area in Uganda is potentially in one of two alternative stable states. We conclude that it is possible to evaluate the utility of PNV maps at a more detailed scale than the level of biome and ecoregion. This indicates that it is possible to map PNV at scales required for reference for restoration and management of forest vegetation. We recommend that empirically based maps of potential natural vegetation are used in restoration planning (biome and PNV maps based on climate envelopes alone may be unreliable tools) as a baseline model for predicting the distribution of reference ecosystems under current and future conditions. It could conveniently be done by deconstructing the existing biome maps, supported by rapid botanical surveys.