Guidelines and Recommendations on Yeast Cell Death Nomenclature

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research

Stream dissolved organic matter in permafrost regions shows surprising compositional similarities but negative priming and nutrient effects

Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28-day incubations. We incubated late-summer stream water from 23 locations nested in seven northern or high-altitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two-way interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways

Guidelines and recommendations on yeast cell death nomenclature

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cel-lular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the defi-nition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differ-ential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death rou-tines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the au-thors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the pro-gress of this vibrant field of research

Biological Normalcy

‘Biological normalcy’ refers to relationships between statistical distributions of biological traits (measures of central tendency and variance) and normative views about what bodies ‘should’ be like or what constitutes a ‘normal’ body

Le déficit en alpha-1 antitrypsine : modèle d’altération de l’homéostasie protéique ou protéostasie

International audienc

The [URE3] prion is not conserved among Saccharomyces species.

The [URE3] prion of Saccharomyces cerevisiae is a self-propagating inactive form of the nitrogen catabolism regulator Ure2p. To determine whether the [URE3] prion is conserved in S. cerevisiae-related yeast species, we have developed genetic tools allowing the detection of [URE3] in Saccharomyces paradoxus and Saccharomyces uvarum. We found that [URE3] is conserved in S. uvarum. In contrast, [URE3] was not detected in S. paradoxus. The inability of S. paradoxus Ure2p to switch to a prion isoform results from the primary sequence of the protein and not from the lack of cellular cofactors as heterologous Ure2p can propagate [URE3] in this species. Our data therefore demonstrate that [URE3] is conserved only in a subset of Saccharomyces species. Implications of our finding on the physiological and evolutionary meaning of the yeast [URE3] prion are discussed

ROTATIONAL-TORSIONAL ANALYSIS OF ELECTRONIC SPECTRA OF JET-COOLED METHYL CYCLOPENTADIENYL RADICAL (CH3.C5H4CH_{3}.C_{5}H_{4} AND CD3−C5H2CD_{3}-C_{5}H_{2})

Author Institution: Laser Spectroscopy Facility, Department of Chemistry, The Ohio State UniversityRotationally resolved electronic spectra of methyl cyclopentadienyl radical ($CH_{3}-C_{5}H_{4}$ and $CD_{3}-C_{3}H_{4}$) were recorded in a cold jet $(T_{rot} = 0.7 K)$. The origin band of the $\bar{B} \longleftrightarrow \bar{X}$ clectronic transition consists of two rotational bands with comparable intensity, which are separated by $2cm^{-1}$ for $CH_{3}-C_{5}H_{4}$, and by $1 cm^{-1}$ for $CD_{3}-C_{5}H_{4}$. The higher frequency band, which has a simple rigid rotor type-A structure, was assigned to a transition between the ground torsional levels $(\tilde{B}, 0a_{1} \longleftrightarrow \tilde{X} Oa_{1})$. The lower frequency band was assigned to a transition between the first excited torsional levels $(\tilde{B}, le \longleftrightarrow - \tilde{X} lc^{\prime\prime})$. The two bands were combined in a joint analysis, by diagonalizing the full torsional-rotational matrices, instead of using the more familiar effective Hamiltonian method. In this way, the rotational parameters $(A_{}r. B$ and C) and torsional parameters ($V_{6}$ and Btop) were directly determined. Then joint fits for $CH_{3}.C_{5}H_{4}$ and $CD_{3}-C_{5}H_{4}$ were performed, realizing that $CH_{3-}$ and $CD^{3-}$ are attached to the same framework, hence, $A_{f}^{H}=A_{f}^{D}$. and using the isotope relationship $B_{top}^{H} = 2B_{top}^{D}$. The torsional parameters in $cm^{-1}$ are: [FIGURE] The dramatic change in the torsional barrier $V_{6}$ upon electronic excitation and its strong isotope dependence will be discussed. Finally, from the direction of the transition moment, we determined the symmetry of the lowest electronic states to be: $\tilde{X}^{2}B_{2}.\bar{A}^{2}A_{2}$ and $\bar{B}^{2}B_{2}