Premise
Apomictic plants (reproducing asexually through seed) often have larger ranges and occur at higher latitudes than closely related sexuals, a pattern known as geographical parthenogenesis ...(GP). Explanations for GP include differences in colonizing ability due to reproductive assurance and direct/indirect effects of polyploidy (most apomicts are polyploid) on ecological tolerances. While life history traits associated with dispersal and establishment also contribute to the potential for range expansion, few studies compare these traits in related apomicts and sexuals.
Methods
We investigated differences in early life history traits between diploid‐sexual and polyploid‐apomictic Townsendia hookeri (Asteraceae), which displays a classic pattern of GP. Using lab and greenhouse experiments, we measured seed dispersal traits, germination success, and seedling size and survival in sexual and apomictic populations from across the range of the species.
Results
While theory predicts that trade‐offs between dispersal and establishment traits should be common, this was largely not the case in T. hookeri. Apomictic seeds had both lower terminal velocity (staying aloft longer when dropped) and higher germination success than sexual seeds. While there were no differences in seedling size between reproductive types, apomicts did, however, have slightly lower seedling survival than sexuals.
Conclusions
These differences in early life history traits, combined with reproductive assurance conferred by apomixis, suggest that apomicts achieve a greater range through advantages in their ability to both spread and establish.
La actual crisis de la COVID-19 está suponiendo un serio obstáculo para el cumplimiento de la Agenda 2030 con la previsión de aumento de la tasa de pobreza mundial y revirtiendo muchos de los logros ...conseguidos en estos últimos años. Igualmente, la pandemia está conllevando el retroceso en el acceso al derecho a una educación de calidad y un aumento de la desigualdad de oportunidades generada por la brecha digital, afectando a millones de estudiantes que han dejado de ir a la escuela. Sin embargo, a pesar de todas las amenazas que despierta el actual contexto se vislumbran las oportunidades que están surgiendo en esta crisis. El cumplimiento de los ODS, sin duda, es una estrategia fundamental para afrontarla y en este sentido la educación para la ciudadanía global es una herramienta clave para acompañar procesos en los que se fomente la construcción de una ciudadanía activa, crítica y generadora de cambios sociales.
In fission yeast, MBF-dependent transcription is inactivated at the end of S phase through a negative feedback loop that involves the co-repressors, Yox1 and Nrm1. Although this repression system is ...well known, the molecular mechanisms involved in MBF activation remain largely unknown. Compacted chromatin constitutes a barrier to activators accessing promoters. Here, we show that chromatin regulation plays a key role in activating MBF-dependent transcription. Gcn5, a part of the SAGA complex, binds to MBF-regulated promoters through the MBF co-activator Rep2 in a cell cycle-dependent manner and in a reverse correlation to the binding of the MBF co-repressors, Nrm1 or Yox1. We propose that the co-repressors function as physical barriers to SAGA recruitment onto MBF promoters. We also show that Gcn5 acetylates specific lysine residues on histone H3 in a cell cycle-regulated manner. Furthermore, either in a gcn5 mutant or in a strain in which histone H3 is kept in an unacetylated form, MBF-dependent transcription is downregulated. In summary, Gcn5 is required for the full activation and correct timing of MBF-regulated gene transcription.
A ruthenium‐catalyzed reductive amination via asymmetric transfer hydrogenation (ATH) has been used to perform an efficient dynamic kinetic resolution (DKR) of N‐aryl 2‐formyl pyrroles decorated with ...a phosphine moiety positioned at the ortho’ position. The strategy relies on the labilization of the stereogenic axis in the substrate facilitated by a transient Lewis acid‐base interaction (LABI) between the carbonyl carbon and the phosphorus center. The reaction features broad substrate scope of aliphatic amines and N‐aryl pyrrole scaffolds, and proceeds under very mild conditions to afford P,N atropisomers in good to high yields and excellent enantioselectivities (up to 99 % ee) for both diphenyl and dicyclohexylphosphino derivatives.
Axially chiral P,N ligands were synthesized through ruthenium‐catalyzed ATH of in situ generated iminophosphines. The transient interaction between iminium and phosphine groups as a Lewis acid‐base pair causes the labilization of the stereogenic axis, enabling the scenario for a DKR. The reaction proceeds with good to high yields and reaching up to 99 % ee across a range of substrates, including both dicyclohexyl‐ and diphenylphosphino derivatives.
Propulsion of luminal content along the gut requires coordinated contractions and relaxations of gastrointestinal smooth muscles controlled by the enteric nervous system. Activation of excitatory ...motor neurons (EMNs) causes muscle contractions, whereas inhibitory motor neuron (IMN) activation causes muscle relaxation. EMNs release acetylcholine (ACh), which acts at muscarinic receptors on smooth muscle cells and adjacent interstitial cells of Cajal, causing excitatory junction potentials (EJPs). IMNs release ATP (or another purine) and nitric oxide to cause inhibitory junction potentials (IJPs) and muscle relaxation. We used commercially available choline acetyltransferase (ChAT)-channelrhodopsin-2 (ChR2)-yellow fluorescent protein (YFP) bacterial artificial chromosome (BAC) transgenic mice, which express ChR2 in cholinergic neurons, to study cholinergic neuromuscular transmission in the colon. Intracellular microelectrodes were used to record IJPs and EJPs from circular muscle cells. We used blue light stimulation (BLS, 470 nm, 20 mW/mm
) and electrical field stimulation (EFS) to activate myenteric neurons. EFS evoked IJPs only, whereas BLS evoked EJPs and IJPs. Mecamylamine (10 µM, nicotinic cholinergic receptor antagonist) reduced BLS-evoked IJPs by 50% but had no effect on electrically evoked IJPs. MRS 2179 (10 µM, a P2Y
receptor antagonist) blocked BLS-evoked IJPs. MRS 2179 and
-nitro-l-arginine (100 µM, nitric oxide synthase inhibitor) isolated the EJP, which was blocked by scopolamine (1 µM, muscarinic ACh receptor antagonist). Immunohistochemistry revealed ChAT expression in ~88% of enhanced YFP (eYFP)-expressing neurons, whereas 12% of eYFP neurons expressed nitric oxide synthase. These data show that cholinergic interneurons synapse with EMNs and IMNs to cause contraction and relaxation of colonic smooth muscle.
Electrical stimulation of interganglionic connectives has been used widely to study synaptic transmission in the enteric nervous system. However, electrical stimulation will activate many types of neurons and nerve fibers, which complicates data interpretation. Optogenetic activation of enteric neurons using genetically modified mice expressing channelrhodopsin-2 in cholinergic neurons offers a new approach that provides more specificity for nerve stimulation when studying myenteric plexus nerve circuitry.
The electricity market in Spain holds significant importance in the nation’s economy and sustainability efforts due to its diverse energy mix that encompasses renewables, fossil fuels, and nuclear ...power. Accurate energy price prediction is crucial in Spain, influencing the country’s ability to meet its climate goals and ensure energy security and affecting economic stakeholders. We have explored how leveraging advanced GPT tools like OpenAI’s ChatGPT to analyze energy news and expert reports can extract valuable insights and generate additional variables for electricity price trend prediction in the Spanish market. Our research proposes two different training and modelling approaches of generative pre-trained transformers (GPT) with specialized news feeds specific to the Spanish market: in-context example prompts and fine-tuned GPT models. We aim to shed light on the capabilities of GPT solutions and demonstrate how they can augment prediction models by introducing additional variables. Our findings suggest that insights derived from GPT analysis of electricity news and specialized reports align closely with price fluctuations post-publication, indicating their potential to improve predictions and offer deeper insights into market dynamics. This endeavor can support informed decision-making for stakeholders in the Spanish electricity market and companies reliant on electricity costs and price volatility for their margins.
In fission yeast, MBF-dependent transcription is required for cells to complete S phase. The MBF transcription factor is regulated through a complex feedback mechanism that involves the co-repressors ...Yox1 and Nrm1 that are loaded onto MBF at the end of S phase, while positive transactivation is achieved through the constitutive binding of the co-activator Rep2. Here we show that Rep2 is required to fully recruit the chromatin remodelers SWI/SNF and RSC to MBF-regulated promoters. On the contrary, Nrm1 and Yox1, when bound to the MBF complex, block the approximation of these chromatin remodelers to MBF-regulated promoters. We propose that SWI/SNF and RSC are recruited to MBF-regulated genes, and RSC together with SAGA complex are important to regulate the G1-to-S transcriptional wave. Mutants of these remodeler complexes are highly sensitive when cells are exposed to insults that challenge DNA synthesis.
An aminocatalytic privileged diversity‐oriented synthesis (ApDOS) strategy utilizing trienamine catalysis for the construction of diverse and complex thiopyrans‐piperidone fused rings through a ...thia‐Diels–Alder/nucleophilic ring‐closing sequence by using dithioamides as activated heterodienophiles is reported. Following this strategy, a super cascade reaction to assemble nine fused rings can be achieved by employing a bis‐dithioamide. Additionally, by linking an indole moiety on the dithioamide, a Pictet–Spengler type reaction can be promoted once the cascade sequence has been achieved, leading to more complex penta‐ hexa‐ and heptacyclic fused ring derivatives in a one‐pot process. This investigation opens new perspectives for the synthesis of a new class of complex and diverse thiopyrans that contribute to populate new relevant regions in the chemical space.
A highly enantioselective thio‐Diels–Alder/nucleophilic ring‐closing cascade reaction utilizing trienamine catalysis with dithioamides is presented. Notably, by linking an indole moiety on the dithioamide, a Pictet–Spengler type reaction can be also promoted, leading to more complex frameworks in a one‐pot process. Additionally, a super cascade sequence to assemble nine fused rings can be achieved by employing a bis‐dithioamide (see scheme).
Abstract
Mucormycosis is a fungal infection caused by Mucorales, with a high mortality rate. However, only a few virulence factors have been described in these organisms. This study showed that ...deletion of
rfs
, which encodes the enzyme for the biosynthesis of rhizoferrin, a siderophore, in
Mucor lusitanicus
, led to a lower virulence in diabetic mice and nematodes. Upregulation of
rfs
correlated with the increased toxicity of the cell-free supernatants of the culture broth (SS) obtained under growing conditions that favor oxidative metabolism, such as low glucose levels or the presence of H
2
O
2
in the culture, suggesting that oxidative metabolism enhances virulence through rhizoferrin production. Meanwhile, growing
M. lusitanicus
in the presence of potassium cyanide, N-acetylcysteine, a higher concentration of glucose, or exogenous cAMP, or the deletion of the gene encoding the regulatory subunit of PKA (
pkaR1
), correlated with a decrease in the toxicity of SS, downregulation of
rfs
, and reduction in rhizoferrin production. These observations indicate the involvement of the cAMP-PKA pathway in the regulation of rhizoferrin production and virulence in
M. lusitanicus
. Moreover,
rfs
upregulation was observed upon macrophage interaction or during infection with spores in mice, suggesting a pivotal role of
rfs
in
M. lusitanicus
infection.
Structure of symplectic Lie groups and momentum map Medina, Alberto
Tohoku mathematical journal/Tohoku mathematical journal. First series/Tohoku mathematical journal. Second series,
09/2015, Letnik:
67, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We describe the structure of the Lie groups endowed with a left-invariant symplectic form, called symplectic Lie groups, in terms of semi-direct products of Lie groups, symplectic reduction and ...principal bundles with affine fiber. This description is particularly nice if the group is Hamiltonian, that is, if the left canonical action of the group on itself is Hamiltonian. The principal tool used for our description is a canonical affine structure associated with the symplectic form. We also characterize the Hamiltonian symplectic Lie groups among the connected symplectic Lie groups. We specialize our principal results to the cases of simply connected Hamiltonian symplectic nilpotent Lie groups or Frobenius symplectic Lie groups. Finally we pursue the study of the classical affine Lie group as a symplectic Lie group. MSC Classes 53D20,70G65 Key words:Symplectic Lie groups,Hamiltonian Lie groups, Symplectic reduction,Symplectic double extension.
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