Browse Articles

Hydrogen-assisted nannochloropsis sp. microalgae biodiesel to operate cleaner diesel engines

Sweet and fatty symbionts: Photosynthetic productivity and carbon storage boosted in microalgae within a host

Symbiosis between a host and intracellular eukaryotic microalgae is a widespread life strategy in aquatic ecosystems. This partnership is considered to be mainly energized by the supply of photosynthetically derived carbon energy from microalgal symbionts. A major question is whether microalgae increase their photosynthetic production and decrease carbon storage in order to maximize carbon translocation to their host. By combining three-dimensional subcellular imaging and physiological analyses, we show that the chloroplast and CO 2 -fixing pyrenoid of the microalga Micractinium conductrix significantly expands during symbiosis within their host (the ciliate Paramecium bursaria ) compared to the free-living stage. This is accompanied by a threefold higher quantity of Rubisco enzymes, 16-fold higher carbon fixation rate per algal cell and upregulation of several Carbon Concentrating Mechanism-related genes. Time-resolved subcellular quantitative imaging revealed that photosynthetically fixed carbon is first allocated to starch during the day, with five times higher production in symbiosis. Nearly half of the carbon stored in starch is consumed overnight while some is converted into lipid droplets, which are 20-fold more voluminous in symbiotic microalgae. We also show that carbon is transferred to the host and potentially respired by the high density of surrounding host mitochondria. Yet, high starch and lipid content in symbiotic microalgae suggest a moderate carbon export to the host relative to the high primary productivity. Overall, this study provides an original view of the subcellular remodeling and dynamics of carbon metabolism of microalgae inside a host, and opens new questions on the mechanisms of the source–sink relationship in aquatic photosymbiosis.

Interpretability of multimodal neural networks for prediction of visual acuity in patients with branch retinal vein occlusion

Genome-wide analysis of mRNA regionalization in a giant single cell

The molecular mechanisms that produce cell structure are poorly understood. The giant ciliate Stentor coeruleus is a unicellular model organism whose large size, reproducible structure, and ability to heal wounds and regenerate allow the formation of structure in a single cell to be addressed using methods of experimental embryology. Such studies have shown that specific cellular structures always form in particular regions of the cell, which raises the question: what is the source of positional information within this organism? By analogy with embryonic development, in which regionalized mRNA is often used to mark position, we asked whether specific regionalized mRNAs might mark position along the anterior–posterior axis of Stentor . By physically bisecting cells and conducting bulk RNA sequencing, we were able to identify sets of messages enriched in either the anterior or posterior half and show that RNAi-mediated knockdown of posterior-enriched transcripts corresponding to MYB genes results in a cell’s inability to regenerate the posterior portion of the cell body. We then conducted half-cell RNA-sequencing in paired anteriors and posteriors of cells in which the microtubule cytoskeleton was disrupted by RNAi of β-tubulin or dynein intermediate chains. We found that many messages either lost their regionalized distribution or switched to an opposite distribution, such that anterior-enriched messages in control became posterior-enriched in the RNAi cells, or vice versa. This study indicates that mRNA can be regionalized within a single giant cell and that microtubules may play a role, possibly by serving as tracks for the movement of the messages.

No aftereffect of motor duration production on auditory duration perception

Abstract Adaptation to stimulus duration causes a repulsive aftereffect on the perceived duration of subsequent stimuli. Most studies investigating duration adaptation have found that the effect is confined to the adapted modality, highlighting unimodal components of duration processing. Here, we use adaptation to test whether motor and auditory duration processing rely on partially shared neural mechanisms by looking for a transfer of the duration aftereffect between these modalities. We asked participants to estimate the perceived duration of auditory stimuli following auditory or motor adaptation. While we replicated the unimodal effects of auditory adaptation, we report that motor adaptation did not produce the typical repulsive aftereffect. We interpret this result as evidence that duration processing by the motor and auditory systems is based on independent mechanisms.

Correction for De Anda et al., The archaeal roots of eukaryotic life

Corrosion behavior of selective laser melted NiTi shape memory alloy

Catch, dock, unravel, and lock

Identification and validation of BLK and OSBPL10 as diagnostic and prognostic biomarkers for nasopharyngeal carcinoma through machine learning algorithms

Scent and adhesion drive insect dispersal of environmental yeast

Insects and terrestrial fungi have lived on planet earth together for over 400 My. Different insect species are commonly associated with distinct mycobiomes. These insect–fungal associations are thought to provide a major dispersal mechanism for fungi in the environment. The Rhodotorula genus of pigmented basidiomycetous yeasts is commonly found in association with insects. Here, we demonstrate that yeasts of Rhodotorula spp. are highly attractive to the vinegar fly Drosophila melanogaster and the African malaria mosquito Anopheles gambiae . We characterized strains of the environmental yeast Rhodotorula taiwanensis that emit simple scent signatures predominated by the common microbial volatile 3-methyl-1-butanol (isoamyl alcohol) alongside other characteristic volatiles including acetone and acetaldehyde. Insect odorant receptors are required for attraction to R. taiwanensis and promote yeast dispersal to new growth niches. In addition to scent, dispersal is also likely mediated by the adhesive qualities of these yeasts to insect cuticles via hydrophobic interactions, as well as consumption. Strikingly, Rhodotorula dispersal was also facilitated by An. gambiae , although mosquitoes often died after becoming stuck to slimy lawns of these yeasts. Our work reveals that scent and adhesion drive insect dispersal of these environmental yeasts.

Hybrid Firefly Algorithm-based optimization of reverse EDM for machining of titanium superalloys for high-precision biomedical applications

Fractional charge density functional theory elucidates electro-inductive and electric field effects at electrochemical interfaces

The application of external voltages to self-assembled monolayers formed on electrodes allows for dynamic tuning of the properties of the constituent molecules. The electrode and the applied voltage give rise to two main effects on the molecules, the electro-inductive and electric field effects, both of which significantly alter their chemical properties and reactivity. We present fractional charge density functional theory coupled with a model electrode and a continuum model solvent (FC-DFT+) to offer quantitative insights into these effects. FC-DFT+ accurately predicts the slope of C ≡ N frequency vs. voltage curve, its frequency-flattening behavior, and ionic strength dependence of the slope. We show that the frequency flattening arises from electro-inductive effects, particularly when the electron count encounters the HOMO–LUMO gap. Further analysis reveals that electro-inductive effects dominate in the nitrile frequency shift, while electric field effects play a smaller but opposing role. FC-DFT+ also confirms that electro-inductive effects being responsible for the flattening behavior of NO 2 stretching frequency by 4-nitrobenzenethiol. In contrast, we show that electric field effects govern the Lewis adduct formation by 4-mercaptopyridine. Our study demonstrates the versatility of FC-DFT+ in predicting both electro-inductive and electric field effects, which should guide a broad spectrum of chemical applications at electrochemical interfaces.

Respiratory muscle training improves post-stroke sarcopenia independent of stroke type, pneumonia, and cardiac comorbidities

Random-with-constraints: Constructing minimal models for high-dimensional biology

Biologists and physicists have a rich tradition of modeling dynamics of living systems with simple models composed of a few interacting components. Despite the remarkable success of this approach, it remains unclear how to use such finely tuned models to study complex biological systems composed of numerous heterogeneous, interacting components. One possible strategy for taming this biological complexity is to embrace the idea that many biological behaviors we observe are “typical” and can be modeled using random systems that respect biologically motivated constraints. Here, we review recent works showing how this approach can be used to make close connection with experiments in biological systems ranging from neuroscience to ecology and evolution and beyond. Collectively, these works suggest that the “random-with-constraints” paradigm represents a promising new modeling strategy for capturing experimentally observed dynamical and statistical features in high-dimensional biological data and provides a powerful minimal modeling philosophy for biology.

Response of yield and quality of wheat with different gluten content to altitude above sea level and nitrogen treatment

The EMB/ATG7-mediated autophagic process regulates neurite outgrowth and promotes enteric neuronal development

The formation of the enteric nervous system (ENS) primarily involves the migration of enteric neural crest-derived cells (ENCCs) and the subsequent maturation of enteric neurons. The developmental dysfunction of ENCCs and enteric neurons can result in ENS disorders, such as hypoganglionosis (HG). Although neurite outgrowth is fundamental to neuronal maturation, the mechanisms by which neurite outgrowth influences neuronal maturation remain poorly defined. Here, we identified EMB as a critical regulator of enteric neuronal maturation. In EMB mutant patients, the expression of EMB is reduced in the enteric neurons of the HG-affected colon. In mice, knockdown of Emb exhibited HG-like features and defects. In vitro experiments, along with analyses using Smart-seq2 and immunoprecipitation-mass spectrometry, demonstrated that EMB is essential for autophagic flux and physically interacts with ATG7, recruiting it to the autophagosomal membrane to facilitate autophagosome formation, and then EMB/ATG7-mediated autophagy promotes neurite outgrowth. Our findings elucidate EMB-mediated autophagy as a pivotal pathway in regulating neurite outgrowth and promoting the maturation of enteric neurons, which provides a mechanistic basis for understanding ENS disorders.

Preoperative virtual reality education for children undergoing surgery: a randomized controlled trial

Human enterotoxigenic <i>Escherichia coli</i> (ETEC) infections elicit antibodies that broadly neutralize mucinases of pathogenic <i>Escherichia coli</i> and <i>Shigella</i>

Enterotoxigenic Escherichia coli (ETEC) and Shigella are the most common bacterial diarrheal pathogens among young children of low-middle income regions. Enteric pathogens must overcome formidable host defenses, including the protective barrier formed by intestinal mucus. ETEC produce a virulence protein called EatA, a member of the Serine Protease Autotransporter of the Enterobacteriae (SPATE) family, where the secreted passenger domain (EatA p ) specifically degrades MUC2, the major mucus secreted by goblet cells of the human intestine. Notably, some Shigella spp., as well as other diarrheagenic E. coli pathovars, secrete homologues of EatA known as SepA, and Pic. Here, we demonstrate that EatA, SepA, and Pic are functionally redundant MUC2 mucinases and that recombinant monoclonal antibodies (mAbs) derived from plasmablasts of ETEC-infected humans can inhibit MUC2 degradation by all three proteases. We present cryo-EM structures of EatA and the related SPATE proteins, SepA, and Pic, complexed to fragment antigen-binding portions of these mAbs to demonstrate that those targeting a core β-helix epitope shared by all three SPATE molecules broadly neutralize the capacity to degrade MUC2. These mAbs effectively prevent MUC2 degradation by each SPATE as well as mucus penetration by ETEC, Shigella flexneri , and Pic-producing enteroaggregative E. coli (EAEC). We anticipate that these studies could facilitate rational design of vaccines that broadly protect against major enteric pathogens by targeting a shared virulence feature.

Enhanced cytotoxic activity and pH-responsive drug delivery of quinalizarin-conjugated gold nanoparticles in non-small cell lung cancer

Lysosomal TMEM165 remodels calcium signaling to drive hypoxia adaptation and tumor progression

Hypoxia is a common stress encountered by animal tissues during development, physiology, and disease. To cope with hypoxic stress, cells remodel metabolic and signaling networks to preserve viability and function. Lysosomes serve as central hubs for metabolic control and intracellular signaling, yet their role in hypoxic adaptation remains unclear. Here, we identify the lysosomal calcium transporter TMEM165 as a hypoxia-responsive regulator of cellular homeostasis. Under hypoxic conditions, TMEM165 expression increases, promoting calcium redistribution from the endoplasmic reticulum to lysosomes and expanding lysosomal calcium storage capacity. TMEM165 activation regulates autophagy and senescence through the AMPK-mTOR and ERK/p21 signaling pathways, respectively. In glioma, high TMEM165 expression correlates with poor prognosis, whereas its depletion suppresses glycolysis, proliferation, and tumor progression. These findings establish TMEM165 as a lysosomal hypoxia-responsive protein that integrates calcium signaling with metabolic and stress-response pathways, revealing a mechanistic link between oxygen availability, lysosomal function, and tumor adaptation.