The arabidopsis COX11 homolog is essential for cytochrome c oxidase activity

Members of the ubiquitous COX11 (cytochrome c oxidase 11) protein family are involved in copper delivery to the COX complex. In this work, we characterize the Arabidopsis thaliana COX11 homolog (encoded by locus At1g02410). Western blot analyses and confocal microscopy identified Arabidopsis COX11 as an integral mitochondrial protein. Despite sharing high sequence and structural similarities, the Arabidopsis COX11 is not able to functionally replace the Saccharomyces cerevisiae COX11 homolog. Nevertheless, further analysis confirmed the hypothesis that Arabidopsis COX11 is essential for COX activity. Disturbance of COX11 expression through knockdown (KD) or over expression (OE) affected COX activity. In KD lines, the activity was reduced by ~50%, resulting in root growth inhibition, smaller rosettes and leaf curling. In OE lines, the reduction was less pronounced (~80% of the wild type), still resulting in root growth inhibition. Additionally, pollen germination was impaired in COX11 KD and OE plants. This effect on pollen germination can only partially be attributed to COX deficiency and may indicate a possible auxiliary role of COX11 in ROS metabolism. In agreement with its role in energy production, the COX11 promoter is highly active in cells and tissues with high-energy demand for example shoot and root meristems, or vascular tissues of source and sink organs. In COX11 KD lines, the expression of the plasma-membrane copper transporter COPT2 and of several copper chaperones was altered, indicative of a retrograde signaling pathway pertinent to copper homeostasis. Based on our data, we postulate that COX11 is a mitochondrial chaperone, which plays an important role for plant growth and pollen germination as an essential COX complex assembly factor.Fil: Radin, Ivan. Technische Universität Dresden; AlemaniaFil: Mansilla, Natanael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Rödel, Gerhard. Technische Universität Dresden; AlemaniaFil: Steinebrunner, Iris. Technische Universität Dresden; Alemani

Locally (co)Cartesian fibrations as realisation fibrations and the classifying space of cospans

We show that the conditions in Steimle's 'additivity theorem for cobordism categories' can be weakened to only require \emph{locally} (co)Cartesian fibrations, making it applicable to a larger class of functors. As an application we compute the difference in classifying spaces between the infinity category of cospans of finite sets and its homotopy category.Comment: 21 pages, comments very welcom

Segalification and the Boardmann-Vogt tensor product

We develop an analog of Dugger and Spivak's necklace formula providing an explicit description of the Segal space generated by an arbitrary simplicial space. We apply this to obtain a formula for the Segalification of $n$-fold simplicial spaces, a new proof of the invariance of right fibrations, and a new construction of the Boardman-Vogt tensor product of $\infty$-operads, for which we also derive an explicit formula.Comment: 21 pages, one figur

The equifibered approach to ∞\infty-properads

We define a notion of $\infty$-properads that generalises $\infty$-operads by allowing operations with multiple outputs. Specializing to the case where each operation has a single output provides a simple new perspective on $\infty$-operads, but at the same time the extra generality allows for examples such as bordism categories. We also give an interpretation of our $\infty$-properads as presheaves on a category of graphs by comparing them to the Segal $\infty$-properads of Hackney-Robertson-Yau. Combining these two perspectives yields a flexible tool for doing higher algebra with operations that have multiple inputs and outputs. The key ingredient to this paper is the notion of an equifibered map between $\mathbb{E}_\infty$-monoids, which is a well-behaved generalisation of free maps. We also use this to prove facts about free $\mathbb{E}_\infty$-monoids, for example that free $\mathbb{E}_\infty$-monoids are closed under pullbacks along arbitrary maps.Comment: 70 pages, 4 figure

Variation of Insect Attracting Odor in Endophytic Epichloë Fungi: Phylogenetic Constrains Versus Host Influence

Odor is a key trait for pollinator attraction in flowering plants, and many studies have investigated odor evolution in the light of pollinator selection by emphasizing the importance of the plant phylogenetic history. By contrast, little is known on the evolution of odors in fungus-insect interactions. In this study, profiles of three volatile compounds that are emitted by grass-inhabiting Epichloë fungi (Clavicipitaceae, Ascomycota) and that have a confirmed or likely role in the attraction of gamete-transferring Botanophila flies were investigated. We collected headspace samples from stromata of six European Epichloë species (including various host races) that originated from different locations in Switzerland, France, Poland, and UK for conducting gas chromatography analyses. Odor profiles exhibited considerable variation, but profiles of most species overlapped and did not discriminate at the species level. The exception was Epichloë festucae, which had a profile dominated by methyl (Z)-3-methyldodec-2-enoate. Based on an Epichloë phylogeny, there was some hierarchical structuring regarding levels of chokol K, another confirmed Botanophila attractant. However, patterns of odor profiles appeared to be largely dependant on particular Epichloë-host associations. The observed variation may be the result of complex selective pressures imposed by Botanophila gametic vectors, local environment, and mycoparasite

Envelopes for Algebraic Patterns

We generalize Lurie's construction of the symmetric monoidal envelope of an $\infty$-operad to the setting of algebraic patterns. This envelope becomes fully faithful when sliced over the envelope of the terminal object, and we characterize its essential image. Using this, we prove a comparison result that allows us to compare analogues of $\infty$-operads over various algebraic patterns. In particular, we show that the $G$-$\infty$-operads of Nardin-Shah are equivalent to "fibrous patterns" over the $(2, 1)$-category $\mathrm{Span}(\mathbb{F}_G)$ of spans of finite $G$-sets. When $G$ is trivial this means that Lurie's $\infty$-operads can equivalently be defined over $\mathrm{Span}(\mathbb{F})$ instead of $\mathbb{F}_*$.Comment: 57 page

Ecological role of volatiles produced by Epichloë: differences in antifungal toxicity

Species of Epichloë (Ascomycota, Clavicipitaceae) are endophytic symbionts of pooid grasses. Sexual reproduction of the fungus depends on gamete-transferring Botanophila flies, which in earlier studies were shown to be specifically attracted by the fungal volatiles chokol K and methyl (Z)-3-methyldodec-2-enoate. As several Epichloë volatiles are known to have antimicrobial properties, it was hypothesised that the original function of insect-attracting volatiles is microbial deterrence. However, the origin of volatile compounds and their toxicity within an ecological context has not yet been clarified. We examined the inhibitory effect of chokol K and methyl (Z)-3-methyldodec-2-enoate on mycoparasites, plant pathogenic fungi and on Epichloë itself at ecologically relevant concentrations, and assessed volatile production in pure cultures of Epichloë on complex and defined media supplemented with inorganic sources of carbon and nitrogen. Chokol K reduced the spore germination of all tested fungi, whereas methyl (Z)-3-methyldodec-2-enoate had no inhibitory effect. Moreover, only chokol K was produced in culture, confirming its fungal origin. Our findings are consistent with the proposed scenario that fungal volatile substances have followed an evolutionary pathway from defence to attractio

Bulk Properties of Liquids and Molecular Properties in Liquids from a Combination of Quantum Chemical Calculations and Classical Simulations

In the first Column of this series we presented an introduction to the title subject including a historical background and some educational aspects. Here, we show how to calculate bulk properties of liquids without claiming to be comprehensive. The next Column will end the cycle with an introduction to the calculation of solvent effects on nuclear and molecular properties