Increasing carotenoid production in Xanthophyllomyces dendrorhous/Phaffia rhodozyma: SREBP pathway activation and promoter engineering
The yeast Xanthophyllomyces dendrorhous synthesizes astaxanthin, a high-value carotenoid with biotechnological relevance in the nutraceutical and aquaculture industries. However, enhancing carotenoid production through strain engineering remains an ongoing challenge. Recent studies have demonstrated that carotenogenesis in X. dendrorhous is regulated by the SREBP pathway, which includes the transcription factor Sre1, particularly in the mevalonate pathway that also produces precursors used for ergosterol synthesis. In this study, we explored a novel approach to enhance carotenoid synthesis by replacing the native crtE promoter, which drives geranylgeranyl pyrophosphate synthesis (the step where carotenogenesis diverges from ergosterol biosynthesis), with the promoter of the HMGS gene, which encodes 3-hydroxy-3-methylglutaryl-CoA synthase from the mevalonate pathway. The impact of this substitution was evaluated in two mutant strains that already overproduce carotenoids due to the presence of an active Sre1 transcription factor: CBS.cyp61-, which does not produce ergosterol and strain CBS.SRE1N.FLAG, which constitutively expresses the active form of Sre1. Wild-type strain CBS6938 was used as a control. Our results showed that this modification increased the crtE transcript levels more than threefold and fourfold in CBS.cyp61.pHMGS/crtE and CBS.SRE1N.FLAG.pHMGS/crtE, respectively, resulting in 1.43-fold and 1.22-fold increases in carotenoid production. In contrast, this modification did not produce significant changes in the wild-type strain, which lacks the active Sre1 transcription factor under the same culture conditions. This study highlights the potential of promoter substitution strategies involving genes regulated by Sre1 to enhance carotenoid production, specifically in strains where the SREBP pathway is activated, offering a promising avenue for strain improvement in industrial applications.
Overexpression of autophagy enhancer PACER/RUBCNL in neurons accelerates disease in the SOD1 ALS mouse model
Amyotrophic lateral sclerosis (ALS) is a debilitating and fatal paralytic disorder associated with motor neuron death. Mutant superoxide dismutase 1 (SOD1) misfolding and aggregation have been linked to familial ALS, with the accumulation of abnormal wild-type SOD1 species being also observed in postmortem tissue of sporadic ALS cases. Both wild-type and mutated SOD1 are reported to contribute to motoneuron cell death. The autophagic pathway has been shown to be dysregulated in ALS. Recent evidence suggests a dual time-dependent role of autophagy in the progression of the disease. PACER, also called RUBCNL (Rubicon-like), is an enhancer of autophagy and has been found diminished in its levels during ALS pathology in mice and humans. Pacer loss of function disturbs the autophagy process and leads to the accumulation of SOD1 aggregates, as well as sensitizes neurons to death. Therefore, here we investigated if constitutive overexpression of PACER in neurons since early development is beneficial in an in vivo model of ALS. We generated a transgenic mouse model overexpressing human PACER in neurons, which then was crossbred with the mutant SOD1 ALS mouse model. Unexpectedly, PACER/SOD1 double transgenic mice exhibited an earlier disease onset and shorter lifespan than did littermate SOD1 mice. The overexpression of PACER in neurons in vivo and in vitro increased the accumulation of SOD1 aggregates, possibly due to impaired autophagy. These results suggest that similar to Pacer loss-of function, Pacer gain-of function is detrimental to autophagy, increases SOD1 aggregation and worsens ALS pathogenesis. In a wider context, our results indicate the requirement to maintain a fine balance of PACER protein levels to sustain proteostasis.
GLUT1 and prorenin receptor mediate differential regulation of TGF-β and CTGF in renal inner medullary collecting duct cells during high glucose conditions
During diabetes, prorenin is highly produced by the renal collecting ducts. The binding of prorenin to (pro)renin receptor (PRR) on the apical plasma membrane triggers intracellular profibrotic genes, including TGF-β and CTGF. However, the underlying mechanisms contributing to the stimulation of these pathways remain unclear. Hence, we hypothesize that the glucose transporter-1 (GLUT1) favors the PRR-dependent stimulation of TGF-β and CTGF in the distal nephron segments during high glucose (HG) conditions.
Advances in genomic tools for plant breeding: harnessing DNA molecular markers, genomic selection, and genome editing
Conventional pre-genomics breeding methodologies have significantly improved crop yields since the mid-twentieth century. Genomics provides breeders with advanced tools for whole-genome study, enabling a direct genotype-phenotype analysis. This shift has led to precise and efficient crop development through genomics-based approaches, including molecular markers, genomic selection, and genome editing. Molecular markers, such as SNPs, are crucial for identifying genomic regions linked to important traits, enhancing breeding accuracy and efficiency. Genomic resources viz. genetic markers, reference genomes, sequence and protein databases, transcriptomes, and gene expression profiles, are vital in plant breeding and aid in the identification of key traits, understanding genetic diversity, assist in genomic mapping, support marker-assisted selection and speeding up breeding programs. Advanced techniques like CRISPR/Cas9 allow precise gene modification, accelerating breeding processes. Key techniques like Genome-Wide Association study (GWAS), Marker-Assisted Selection (MAS), and Genomic Selection (GS) enable precise trait selection and prediction of breeding outcomes, improving crop yield, disease resistance, and stress tolerance. These tools are handy for complex traits influenced by multiple genes and environmental factors. This paper explores new genomic technologies like molecular markers, genomic selection, and genome editing for plant breeding showcasing their impact on developing new plant varieties.
EZH1/2 plays critical roles in oocyte meiosis prophase I in mice
abnormalities or defects in oocyte meiosis can result in decreased oocyte quality, reduced ovarian reserve, and female diseases. However, the mechanisms of oocyte meiosis remain largely unknown, especially epigenetic regulation. Here, we explored the role of EZH1/2 (histone methyltransferase of H3K27) in mouse oocyte meiosis by inhibiting its activity and deleting its gene.
The sodium/ascorbic acid co-transporter SVCT2 distributes in a striated membrane-enriched domain at the M-band level in slow-twitch skeletal muscle fibers
Vitamin C plays key roles in cellular homeostasis, functioning as a potent antioxidant and a positive regulator of cell differentiation. In skeletal muscle, the vitamin C/sodium co-transporter SVCT2 is preferentially expressed in oxidative slow fibers. SVCT2 is up-regulated during the early fusion of primary myoblasts and decreases during initial myotube growth, indicating the relevance of vitamin C uptake via SVCT2 for early skeletal muscle differentiation and fiber-type definition. However, our understanding of SVCT2 expression and function in adult skeletal muscles is still limited.
Phenotyping of a new yeast mapping population reveals differences in the activation of the TORC1 signalling pathway between wild and domesticated yeast strains
Domestication can be understood as a symbiotic relationship that benefits both domesticator and domesticated species, involving multiple genetic changes that configure the phenotype of the domesticated species. One of the most important domesticated species is the yeast Saccharomyces cerevisiae, with both domesticated strains used for different fermentations processes for thousands of years and wild strains existing only in environments without human intervention; however, little is known about the phenotypic effects associated with its domestication. In the present work, we studied the effect of domestication on yeast TORC1 activation, a pleiotropic signalling pathway conserved across the eukaryotic domain. To achieve this goal, we improved a previously generated methodology to assess TORC1 activation, which turned out to be as effective as the original one but also presents several practical advantages for its application (such as facilitating confirmation of transformants and putting the Luc reporter gene under the control of the same P promoter for each transformed strain). We then generated a mapping population, the so-called TOMAN-G population, derived from the "1002 Yeast Genomes Project" population, the most comprehensive catalogue of the genetic variation in yeasts. Finally, strains belonging to the TOMAN-G population were phenotyped for TORC1 activation, and then we compared the results obtained between yeast strains with different ecological origins, finding differences in TORC1 activation between wild and domesticated strains, particularly wine strains. These results are indicative of the effect of domestication on TORC1 activation, specifically that the different evolutionary trajectories of wild and domesticated strains have in fact caused differences in the activation of this pathway; furthermore, the phenotypic data obtained in this work could be used to continue underlying the genetic bases of TORC1 activation, a process that is still not fully understood, using techniques such as GWAS to search for specific genetic variants underlying the observed phenotypic variability and phylogenetic tree inferences to gain insight into the evolutionary relationships between these genetic variants.
Impact of salmon farming in the antibiotic resistance and structure of marine bacterial communities from surface seawater of a northern Patagonian area of Chile
Aquaculture and salmon farming can cause environmental problems due to the pollution of the surrounding waters with nutrients, solid wastes and chemicals, such as antibiotics, which are used for disease control in the aquaculture facilities. Increasing antibiotic resistance in human-impacted environments, such as coastal waters with aquaculture activity, is linked to the widespread use of antibiotics, even at sub-lethal concentrations. In Chile, the world's second largest producer of salmon, aquaculture is considered the primary source of antibiotics residues in the coastal waters of northern Patagonia. Here, we evaluated whether the structure and diversity of marine bacterial community, the richness of antibiotic resistance bacteria and the frequency of antibiotic resistance genes increase in communities from the surface seawater of an area with salmon farming activities, in comparison with communities from an area without major anthropogenic disturbance.
Enrichment of trimethyl histone 3 lysine 4 in the Dlk1 and Grb10 genes affects pregnancy outcomes due to dietary manipulation of excess folic acid and low vitamin B12
The aberrant expression of placental imprinted genes due to epigenetic alterations during pregnancy can impact fetal development. We investigated the impact of dietary modification of low vitamin B12 with varying doses of folic acid on the epigenetic control of imprinted genes and fetal development using a transgenerational model of C57BL/6J mice. The animals were kept on four distinct dietary combinations based on low vitamin B12 levels and modulated folic acid, mated in the F0 generation within each group. In the F1 generation, each group of mice is split into two subgroups; the sustained group was kept on the same diet, while the transient group was fed a regular control diet. After mating, maternal placenta (F1) and fetal tissues (F2) were isolated on day 20 of gestation. We observed a generation-wise opposite promoter CpG methylation and gene expression trend of the two developmental genes Dlk1 and Grb10, with enhanced gene expression in both the sustained and transient experimental groups in F1 placentae. When fetal development characteristics and gene expression were correlated, there was a substantial negative association between placental weight and Dlk1 expression (r = - 0.49, p < 0.05) and between crown-rump length and Grb10 expression (r = - 0.501, p < 0.05) in fetuses of the F2 generation. Consistent with these results, we also found that H3K4me3 at the promoter level of these genes is negatively associated with all fetal growth parameters. Overall, our findings suggest that balancing vitamin B12 and folic acid levels is important for maintaining the transcriptional status of imprinted genes and fetal development.
Depression like-behavior and memory loss induced by methylglyoxal is associated with tryptophan depletion and oxidative stress: a new in vivo model of neurodegeneration
Depression and memory loss are prevalent neurodegenerative disorders, with diabetic patients facing an elevated risk of brain dysfunction. Methylglyoxal (MGO) formation, which is heightened in diabetes owing to hyperglycemia and gut dysbiosis, may serve as a critical link between diabetes and brain diseases. Despite the high prevalence of MGO, the precise mechanisms underlying MGO-induced depression and memory loss remain unclear.
H Antigen expression modulates epidermal Keratinocyte Integrity and differentiation
ABO blood group antigens (ABH antigens) are carbohydrate chains glycosylated on epithelial and red blood cells. Recent findings suggest reduced ABH expression in psoriasis and atopic dermatitis, a chronic inflammatory skin disease with retained scale. H antigen, a precursor for A and B antigens, is synthesized by fucosyltransferase 1 (FUT1). Desmosomes, critical for skin integrity, are known to require N-glycosylation for stability. We investigate the impact of H antigens, a specific type of glycosylation, on desmosomes in keratinocytes.
Oviduct epithelial spheroids during in vitro culture of bovine embryos mitigate oxidative stress, improve blastocyst quality and change the embryonic transcriptome
In vitro embryo production is increasingly used for genetic improvement in cattle but bypasses the oviduct environment and exposes the embryos to oxidative stress with deleterious effects on further development. Here we aimed to examine the effect of oviduct epithelial spheroids (OES) on embryo development and quality in terms of morphology and gene expression during two co-culture times (4 days: up to embryonic genome activation at 8-16 cell stage vs. 7 days: up to blastocyst stage) and under two oxygen levels (5% vs. 20%).
Cisplatin-resistance and aggressiveness are enhanced by a highly stable endothelin-converting enzyme-1c in lung cancer cells
Lung cancer constitutes the leading cause of cancer mortality. High levels of endothelin-1 (ET-1), its cognate receptor ETR and its activating enzyme, the endothelin-converting enzyme-1 (ECE-1), have been reported in several cancer types, including lung cancer. ECE-1 comprises four isoforms, which only differ in their cytoplasmic N-terminus. Protein kinase CK2 phosphorylates the N-terminus of isoform ECE-1c, increasing its stability and leading to enhanced invasiveness in glioblastoma and colorectal cancer cells, which is believed to be mediated by the amino acid residue Lys-6, a conserved putative ubiquitination site neighboring the CK2-phosphorylated residues Ser-18 and Ser-20. Whether Lys-6 is linked to the acquisition of a cancer stem cell (CSC)-like phenotype and aggressiveness in human non-small cell lung cancer (NSCLC) cells has not been studied.
Enhancing late postmortem interval prediction: a pilot study integrating proteomics and machine learning to distinguish human bone remains over 15 years
Determining the postmortem interval (PMI) accurately remains a significant challenge in forensic sciences, especially for intervals greater than 5 years (late PMI). Traditional methods often fail due to the extensive degradation of soft tissues, necessitating reliance on bone material examinations. The precision in estimating PMIs diminishes with time, particularly for intervals between 1 and 5 years, dropping to about 50% accuracy. This study aims to address this issue by identifying key protein biomarkers through proteomics and machine learning, ultimately enhancing the accuracy of PMI estimation for intervals exceeding 15 years.
Landscape transcriptomic analysis of bovine follicular cells during key phases of ovarian follicular development
There are many gaps in our understanding of the mechanisms involved in ovarian follicular development in cattle, particularly regarding follicular deviation, acquisition of ovulatory capacity, and preovulatory changes. Molecular evaluations of ovarian follicular cells during follicular development in cattle, especially serial transcriptomic analyses across key growth phases, have not been reported. This study aims to address this gap by analyzing gene expression using RNA-seq in granulosa and antral cells recovered from ovarian follicular fluid during critical phases of ovarian follicular development in Holstein cows.
Ozone therapy mitigates parthanatos after ischemic stroke
Stroke is a leading cause of death worldwide, with oxidative stress and calcium overload playing significant roles in the pathophysiology of the disease. Ozone, renowned for its potent antioxidant properties, is commonly employed as an adjuvant therapy in clinical settings. Nevertheless, it remains unclear whether ozone therapy on parthanatos in cerebral ischemia-reperfusion injury (CIRI). This study aims to investigate the impact of ozone therapy on reducing parthanatos during CIRI and to elucidate the underlying mechanism.
DLK1 and DLK2, two non-canonical ligands of NOTCH receptors, differentially modulate the osteogenic differentiation of mesenchymal C3H10T1/2 cells
C3H10T1/2 is a mesenchymal cell line capable of differentiating into osteoblasts, adipocytes and chondrocytes. The differentiation of these cells into osteoblasts is modulated by various transcription factors, such as RUNX2. Additionally, several interconnected signaling pathways, including the NOTCH pathway, play a crucial role in modulating their differentiation into mature bone cells. We have investigated the roles of DLK1 and DLK2, two non-canonical inhibitory ligands of NOTCH receptors, in the osteogenic differentiation of C3H10T1/2 cells.
Comparative study of the growth, stress status and reproductive capabilities of four wild-type zebrafish (Danio rerio) lines
Zebrafish are widely used in various research fields and to fulfil the diverse research needs, numerous zebrafish lines are available, each with a unique domestication background, potentially resulting in intraspecies differences in specific biological functions. Few studies have compared multiple zebrafish lines under identical conditions to investigate both inter- and intra-line variability related to different functions. However, such variability could pose a challenge for the reproducibility of results in studies utilising zebrafish, particularly when the line used is not clearly specified. This study assessed growth, stress status (cortisol, serotonin) and reproductive capabilities (maturity, fecundity, fertilisation rate, sperm quality) of four commonly used wild-type zebrafish lines (AB, SJD, TU, WIK) using standardized protocols.
Identification and functional characteristics of CHD1L gene variants implicated in human Müllerian duct anomalies
Müllerian duct anomalies (MDAs) are congenital developmental disorders that present as a series of abnormalities within the reproductive tracts of females. Genetic factors are linked to MDAs and recent advancements in whole-exome sequencing (WES) provide innovative perspectives in this field. However, relevant mechanism has only been investigated in a restricted manner without clear elucidation of respective observations.
Maternal stress during pregnancy alters circulating small extracellular vesicles and enhances their targeting to the placenta and fetus
Maternal psychological distress during pregnancy can negatively impact fetal development, resulting in long-lasting consequences for the offspring. These effects show a sex bias. The mechanisms whereby prenatal stress induces functional and/or structural changes in the placental-fetal unit remain poorly understood. Maternal circulating small extracellular vesicles (sEVs) are good candidates to act as "stress signals" in mother-to-fetus communication. Using a repetitive restraint-based rat model of prenatal stress, we examined circulating maternal sEVs under stress conditions and tested whether they could target placental-fetal tissues.
LYP regulates SLP76 and other adaptor proteins in T cells
The LYP tyrosine phosphatase presents a SNP (1858C > T) that increases the risk of developing autoimmune diseases such as type I diabetes and arthritis. It remains unclear how this SNP affects LYP function and promotes the development of these diseases. The scarce information about LYP substrates is in part responsible for the poor understanding of LYP function.