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Comparative genomics and full-length transcriptome profiling of wing morphs in Tetrix grossus (Orthoptera: Tetrigidae).

Wing polymorphism represents a paradigmatic dispersal-reproduction trade-off, yet its molecular basis remains uncharacterised in the phylogenetically distant pygmy grasshoppers (Tetrigidae). Here we integrate comparative genomics across ten orthopteran species with full-length transcriptomics of long-winged (FL) and short-winged (FS) Tetrix grossus. OrthoFinder recovered 118 orthogroups specific to T. grossus. Against a backdrop of pronounced gene-family contraction (36 expansions versus 222 contractions; net -186, mirrored at the ancestral Tetrix node, +37/-140), we identified an ancestral, Tetrix-specific expansion of hormone-regulation (12 genes; fold enrichment 7.93) and lipid/carbohydrate-metabolic families organised into syntenic clusters, alongside 513 positively selected genes enriched for integrin-mediated cell adhesion (6 genes), a process relevant to epithelial and appendage morphogenesis. Full-length transcriptomics of one long-winged (FL) and one short-winged (FS) adult female detected 7530 (FL) and 7515 (FS) expressed genes, with 794 FL- and 776 FS-restricted transcriptome-derived SNP-associated genes. The FL morph was enriched for an EGFR/Ras-Rho developmental-patterning axis and neuromuscular flight genes, whereas the FS morph was enriched for insulin/peptide-hormone response and growth-regulatory loci. Overall, we present genomic resources and testable hypotheses concerning the evolution and regulation of wing morphs in Tetrigidae rather than a validated genetic architecture of wing-morph determination.

Animals

Comparison of three tracking methods to assess usage of two pediatric powered mobility devices for young children with cerebral palsy.

Powered mobility devices are underutilized for promoting self-initiated mobility in young children with cerebral palsy due to prioritization of walking, caregiver effort, device characteristics, and environmental factors. Understanding device usage patterns is important to assess the impact of powered mobility interventions on child outcomes. As part of clinical trial (NCT04684576), three objective tracking methods including integrated loggers, Global Positioning System trackers (GPST), and caregiver reported activity logs (CRAL) were compared to provide insights into device usage patterns. Metrics included play session frequency, session duration, total usage minutes, and unique usage days for two powered mobility devices: Modified Ride-on Cars (MROC) and the Permobil Explorer Mini (EM). Twelve children with cerebral palsy used each device for eight consecutive weeks in home and community settings (16 weeks total), with device ordered randomized. Results showed no significant differences among tracking methods for the MROC. For the EM, only session duration differed between GPST and CRAL. Correlation analysis revealed variable relationships amongst tracking methods for both devices. The EM was used more frequently than the MROC, with significantly greater total usage minutes and session duration via CRAL, not GPST. The findings highlight the need for reliable tracking technologies that can be used across powered mobility devices.

Child, Preschool

Integrative multi-omics reveals a fibroblast-centered, ZFHX3-prioritized regulatory framework linking sick sinus syndrome and atrial fibrillation.

OBJECTIVE: To define shared genetic and multi-scale mechanisms underlying comorbidity between sick sinus syndrome (SSS) and atrial fibrillation (AF). METHODS: We integrated genome-wide association study (GWAS) summary statistics for SSS and AF with Genotype-Tissue Expression (GTEx) expression and splicing quantitative trait loci (eQTL/sQTL), atrial single-cell and spatial transcriptomics, and epigenomics. We identified trait-relevant tissues and pathways, prioritized shared cell types, quantified genome-wide and local genetic sharing, detected joint loci by cross-trait meta-analysis, and linked loci to regulatory programs via colocalization and cell-prioritized co-expression networks. RESULTS: Both traits showed strongest enrichment in cardiac tissue, especially Heart Atrial Appendage. Fibroblasts from the left atrial appendage were consistently prioritized as the key shared cell population. SSS and AF displayed significant positive genome-wide genetic correlation, with multiple locally shared regions, including six major loci. Cross-trait meta-analysis identified eight joint-phenotype SNPs implicating four susceptibility genes. ZFHX3 was the leading tissue-cell-gene candidate, acting as a hub in fibroblast co-expression modules and colocalizing with cardiac regulatory signals. CONCLUSION: Shared liability for SSS and AF is highly tissue- and cell-specific, converging on regulatory networks in atrial appendage fibroblasts, with ZFHX3 serving as a central mechanistic and biomarker node.

Humans

Glycaemic burden disrupts innate immunity in TB by modulating CD206 expression and macrophage antimicrobial responses.

Tuberculosis (TB) and diabetes mellitus (DM) represent a growing dual global health burden, with chronic hyperglycaemia recognized as a major modifier of host immunity against Mycobacterium tuberculosis (Mtb). Macrophages, central to pathogen recognition, phagocytosis, antigen presentation, and intracellular killing, may be particularly vulnerable to diabetic metabolic dysregulation. This study evaluated phenotypic and functional macrophage alterations in individuals with pulmonary TB, type 2 DM, TB-DM comorbidity, and healthy controls. Surface receptor expression was analysed by multicolour flow cytometry, while phagocytosis and intracellular bacterial clearance were assessed using FITC-labelled Mtb assays and colony-forming unit enumeration. Hyperglycaemia was associated with reduced CD11b, MARCO, and TLR2 expression alongside upregulation of the mannose receptor CD206, which correlated positively with HbA1c levels, indicating a shift toward a permissive M2-like phenotype. Phagocytic uptake of Mtb was significantly impaired and inversely correlated with HbA1c. Antigen-presenting capacity was selectively compromised, with reduced CD80 and CD86 expression in DM and TB-DM groups, while HLA-DR remained unchanged. Intracellular Mtb killing was markedly diminished in diabetic macrophages. These findings demonstrate that chronic hyperglycaemia profoundly disrupts macrophage innate immunity, contributing to increased TB susceptibility and poor infection control in diabetic populations.

Humans

Longitudinal Relations among Perceived Economic Stress, Teacher-Student Relationships, and Cybervictimization: Exploring Within-Person Links.

Family economic hardship has been identified as a risk factor for adolescents' cybervictimization. Nevertheless, existing studies have primarily focused on objective economic conditions, and little is known about the within-person association between perceived economic stress and adolescents' cybervictimization and the mediating mechanisms underlying this association. To fill these gaps, the random intercept cross-lagged model was employed to examine the dynamic relations among perceived economic stress, teacher-student relationships, and cybervictimization. The data were obtained from a sample of 2407 Chinese adolescents (Mage = 12.75, SD = 0.58, 50.23% girls at baseline) recruited from seven schools and assessed at three time points over one year. At the between-person level, there were no significant associations among perceived economic stress, teacher-student relationships, and cybervictimization. At the within-person level, perceived economic stress positively predicted later cybervictimization over time, and this effect was unidirectional. The bidirectional relations between perceived economic stress and teacher-student relationships remained stable over time. Cybervictimization significantly and negatively predicted subsequent teacher-student relationships across time, indicating a unidirectional predictive effect. Additionally, perceived economic stress indirectly predicted cybervictimization through teacher-student relationships. The findings highlight the importance of distinguishing within-person from between-person processes and shed light on the longitudinal role of teacher-student relationships in the association between perceived economic stress and cybervictimization.

Humans

Mechanistic insights into flavor deterioration in bitter sturgeon caviar: Evidence from lipidomics and metagenomics.

This study systematically compared the flavor and multi-omics differences between normal caviar and bitter caviar based on quantitative descriptive analysis (QDA), volatile compounds (VOCs) analysis, untargeted lipidomics, and metagenomics. The results showed that bitter caviar was characterized not only by increased bitterness, but also by decreased positive sensory attributes, including buttery, nutty, and marine fresh. VOCs analysis indicated that the volatile profile of bitter caviar was reorganized. Compounds such as 3-hydroxy-2-butanone, 1-octen-3-ol, and (E, Z)-2,6-nonadienal showed higher relative odor activity values (rOAVs); however, these changes did not improve its overall sensory experience. Untargeted lipidomics identified 492 differential lipids. These changes were mainly characterized by decreased PC and increased DG and LPC in bitter caviar. KEGG pathways analysis showed that these differential lipids were mainly associated with glycerophospholipid metabolism, choline metabolism in cancer, and retrograde endocannabinoid signaling. Metagenomic analysis showed that bacteria dominated the microbial community of caviar. Among them, Bacillus and Micromonospora showed relatively high abundance in the caviar microbiota. They were also closely associated with lipid metabolic changes involving PC, DG, and LPC, suggesting their potential as candidate targets for future microbiota-directed regulation of caviar quality. These findings provide new insights into the mechanisms underlying sensory deterioration and flavor formation in bitter caviar, and offer a theoretical basis for improving caviar quality in industrial production.

Animals

List randomization for prevalence estimation of sensitive behavioral data among women with HIV of reproductive age in Lilongwe, Malawi.

Self-reported data are subject to reporting biases, including social desirability bias. List randomization is one method that can help mitigate the impact of such biases. Here, we examined the utility of list randomization among women of reproductive age living with HIV in sub-Saharan Africa. In the Family Planning and Antiretroviral Therapy study, participants were randomized to answer 5 blocks of true/false statements via either direct or list response. Each block contained 3 nonsensitive statements and 1 sensitive statement related to either condom use or HIV disclosure. For each sensitive statement, we calculated the prevalence difference (PD) comparing list response to direct response overall and stratified by socioeconomic status. The PD for 4 of the sensitive statements was negligible. However, we found that self-report of always using a condom was reported by 53.1% at list response visits vs 34.7% at direct response visits (PD, 18.5%; 95% CI, 6.2%-30.7%), a difference that was attenuated among those with higher socioeconomic status. In this setting, list randomization did not meaningfully change the estimated prevalence for most questions, except for one question, which unexpectedly produced a higher estimate for a positive behavior. Examining this method in other settings and populations is warranted.

Humans

Maternal age as a driver of genome instability: mechanisms linking aneuploidy, mutagenesis and mitochondrial dysfunction.

Advanced maternal age is a well-established risk factor for adverse reproductive outcomes due to increased rates of aneuploidy. However, emerging evidence indicates that the genetic consequences of maternal aging extend well beyond chromosome mis-segregation. Aging oocytes acquire a broad spectrum of genetic abnormalities, including maternally derived nuclear de novo mutations (DNMs) and mitochondrial DNA mutations, together with epigenetic dysregulation of DNA methylation and post-translational modification levels. These changes reflect the unique biology of the female germline in which oocytes remain arrested in meiotic prophase I for decades. Age-related deterioration of key processes, such as erosion of cohesion complexes, altered meiotic recombination, and weakened spindle assembly checkpoint surveillance collectively destabilize meiotic chromosome architecture, directly driving chromosome mis-segregation. At the same time, accumulation of endogenous DNA damage and declining DNA damage and repair processes increase the chances of transmitting lesions that can be converted into sequence-level mutations during the earliest embryonic divisions, when genome maintenance relies exclusively on maternal factors. High-resolution sequencing studies further demonstrate that maternal aging is associated with increased DNMs burden in both nuclear and mitochondrial DNA. Together, these findings support a model in which maternal aging is a driver of genome-wide instability that links aneuploidy and mutagenesis through shared defects in meiotic surveillance, declining DNA repair efficiency, and mitochondrial function. This framework positions delayed childbearing as a multifaceted genetic risk factor that extend beyond aneuploidy to include mutations and other genomic alterations that can impact intergenerational genetic risk.

Aneuploidy

The mediating role of protective factors in relationship between caregiving components and psychosocial adjustment among young carers: a meta-analysis.

OBJECTIVE: Higher youth caregiving is associated with poorer psychosocial outcomes in young carers; hence a research priority is to investigate protective factors that mitigate the adverse effects of youth caregiving. This systematic review with meta-analysis examined the relationships among youth caregiving components and young carer psychosocial adjustment and protective factors, as well as the mediating role of the protective factors in the relationship between caregiving components and psychosocial adjustment. METHODS: Three electronic databases were searched until April 2024 and 10,244 unique publications were identified. Following abstract and title screening, 422 publications were subjected to full-text screening and 60 quantitative studies were included in this study. RESULTS: Meta-analytic structural equation modeling (MASEM) results revealed positive direct effects of caregiving responsibilities and caregiving experiences on benefit finding (&#x3b2;&#xa0;=&#xa0;.43, 95% CI [.074, .782], p&#xa0;<&#xa0;.05) and emotion regulation (&#x3b2;&#xa0;=&#xa0;.72, 95% CI [.44, 1.00], p&#xa0;<&#xa0;.001), respectively. However, there was neither a significant direct effect of caregiving components on psychosocial adjustment nor a significant indirect effect of caregiving components on psychosocial adjustment through benefit finding or emotion regulation. CONCLUSION: Findings revealed a need for research into how caregiving contextual factors affect relations among youth caregiving, protective factors, and adjustment.

Humans

Multi-omics analysis reveals coordinated epigenetic dysregulation in atrazine-induced dopaminergic neurotoxicity.

Atrazine (ATR), a widely used triazine herbicide, has been linked to neurotoxicity, yet the epigenetic mechanisms underlying its dopaminergic effects remain unclear. This study investigated whether coordinated miRNA dysregulation and DNA methylation alterations contribute to ATR-induced Parkinson's disease (PD)-like neurotoxicity. Male Sprague-Dawley rats were administered ATR (50&#x202f;mg/kg/day) for 90 days, resulting in motor and cognitive deficits with dopaminergic dysfunction, including increased &#x3b1;-synuclein and reduced tyrosine hydroxylase expression. Small RNA sequencing identified 72 differentially expressed miRNAs in the substantia nigra, enriched in PI3K-Akt, MAPK, and Ras signaling pathways. In a cohort of six PD patients and six matched controls, genome-wide DNA methylation profiling revealed 4694 differentially methylated positions, predominantly hypomethylated, with overlapping enrichment in neuronal signaling pathways. Weighted gene co-expression network analysis identified a PD-associated module strongly correlated with disease status (r&#x202f;=&#x202f;-0.95, P&#x202f;<&#x202f;0.001). Multi-omics integration identified CASP3 as a central hub gene. External validation supported CASP3 relevance in PD (AUC&#x202f;=&#x202f;0.833), and molecular docking suggested potential ATR-CASP3 interaction. Further analysis predicted upregulated miR-3552 as a potential upstream regulator of CASP3. These findings indicate that ATR-induced neurotoxicity may be mediated through the miR-3552/CASP3 signaling axis, ultimately regulating apoptosis and contributing to neurodegeneration.

Animals

Olive leaf protein hydrolysates yield gastro-resistant peptides with antioxidant and anti-inflammatory potential: peptidomics, in vitro validation and molecular docking analyses.

Olive (Olea europaea L.) leaves are an abundant olive-oil by-product and a promising feedstock for sustainable valorisation. An olive leaf protein isolate (OLPI) from olive-leaf powder (OLP) was enzymatically hydrolysed to yield seven hydrolysates (OLPHs). All showed notable antioxidant activity as whole hydrolysate matrices (EC&#x2085;&#x2080;&#xa0;=&#xa0;0.11-0.28&#xa0;mg&#xa0;mL-1); likely reflecting the combined contribution of released peptides and co-extracted phenolic compounds; the 15-min Alcalase product (OLPH15A) showed high activity with the shortest processing time. Its INFOGEST digest (dOLPH15A) attenuated LPS-induced inflammation in Caco-2 cells, down-regulating pro-inflammatory and up-regulating anti-inflammatory genes. Peptidomics identified 7037 peptides in OLPH15A and 534 in dOLPH15A, from which twenty gastro-resistant sequences were prioritised for in silico analysis. Multi-tool prediction and docking highlighted four peptides, GAAGGIGQPL, QSAYPGTGPL, GGGAGGGDGGIL and LDAQFPGVN, with favourable predicted affinity for the TLR4/MD2 complex, suggesting that they may contribute to the observed immunomodulatory response. These findings position olive leaves as a viable source of protein hydrolysate-based ingredients with antioxidant and anti-inflammatory potential, advancing the valorisation of olive-oil by-products.

Olea

Ecological momentary assessment studies on food craving among healthy adults: A systematic review.

Ecological Momentary Assessment (EMA) can capture the dynamic nature of food craving in free-living conditions, addressing limitations of laboratory and retrospective reporting methods. This systematic review synthesized findings from EMA studies to characterize 1) methodological features, 2) the temporal dynamics of food craving, and 3) the relationship between craving and eating behaviors. A systematic search of PubMed and PsycINFO databases was conducted following PRISMA guidelines. The review included 23 studies that utilized EMA designs to assess food craving repeatedly in daily life among healthy adults. Most studies employed EMA protocols that prompted participants to respond at pre-specified time points and utilized single-item craving measures. Most craving measures (71%) lacked specificity regarding the type of food craved. Results revealed a consistent positive within-person association between hunger and food craving. Conversely, associations between stress/negative affect and craving were inconsistent, varying by individual traits and context. Momentary food craving appeared to predict subsequent eating outcomes. Evidence suggested food craving may be a dynamic, transient state that co-fluctuates with hunger, functioning as a proximal antecedent to food intake. However, reliance on non-specific food craving measures and EMA protocols prompting at fixed schedules limits the granular understanding of craving mechanisms. Future research requires refining food craving measurement and incorporating randomized prompting within predefined windows, or participant-initiated sampling triggered by specific events (e.g., eating occasion), to better characterize food craving dynamics in relation to eating behaviors.

Humans

Deciphering S-nitrosylation-regulated metabolic networks in postmortem beef based on label-free modificomics: Identification of ferroptosis as a novel quality-related pathway.

This study elucidated the molecular mechanisms of S-nitrosylation on postmortem beef metabolism and quality based on the label-free modificomics. Varying degrees of S-nitrosylation were exogenously induced in beef semimembranosus (SM) muscle. Results indicated that a high S-nitrosylation level significantly increased beef pH and Warner-Bratzler shear force (WBSF) while reducing centrifugal loss (P&#xa0;<&#xa0;0.05). A total of 828&#xa0;S-nitrosylated proteins and 1458 modification sites were identified, of which 114 sites on 81 proteins (DSNPs) exhibited differential modification abundance, representing an increase of 125% compared with previous proteomics studies. DSNPs were mainly involved in glycolysis, the tricarboxylic acid cycle, oxidative phosphorylation, calcium signaling, cell structure, and ferroptosis. Notably, this study provides the first evidence in postmortem muscle that S-nitrosylation regulates key ferroptosis-related proteins, including ACSL, CP, and TF, offering new insights into the link between S-nitrosylation and the ferroptosis pathway in meat. Correlation analysis demonstrated that TF was significantly negatively correlated with pH and WBSF, but positively correlated with centrifugal loss (P&#xa0;<&#xa0;0.05). Collectively, protein S-nitrosylation critically modulates postmortem beef quality through the coordinated regulation of multiple metabolic processes. More importantly, the identification of ferroptosis as a S-nitrosylation-sensitive pathway provides a new perspective for regulating meat quality through protein post-translational modifications.

Animals

Clinical Outcomes and Patient Experiences With Celiprolol Therapy in Vascular Ehlers-Danlos Syndrome: The First Non-European Cohort.

Vascular Ehlers-Danlos syndrome (vEDS) is a hereditary connective tissue disorder caused by heterozygous pathogenic variants in COL3A1. European studies have shown that celiprolol may reduce the risk of life-threatening vascular events, but outcomes in non-European populations and the therapy's psychological impact remain unclear. We conducted a retrospective cohort study of individuals aged &#x2265;&#x2009;20&#x2009;years with genetically confirmed vEDS in a single referral center in Japan between 2000 and 2024. Clinical, molecular, and treatment data were obtained from medical records, and semi-structured interviews were conducted with a subset of participants to assess patient experiences. Twenty-six patients were included. The mean age at celiprolol initiation was 36.9&#x2009;years, with a mean follow-up of 96.6&#x2009;months. All patients received celiprolol, and 61.5% reached the target dose (400&#x2009;mg/day). One patient died of hepatic artery rupture; vascular events occurred in 11, while 14 remained event-free. No significant associations were observed between vascular event occurrence and genotype or celiprolol dose. Interviews with 11 patients revealed that celiprolol use provided emotional reassurance and promoted a more proactive approach to disease management. Celiprolol therapy may reduce fatal vascular events in vEDS and have a positive psychological impact, though nonfatal vascular complications remain frequent.

Humans

Direct background subtraction LC-MS/MS assay for human plasma progesterone: Full validation and comparative application.

OBJECTIVE: To develop and validate a liquid chromatography-tandem mass spectrometry method based on direct background subtraction for the quantification of endogenous progesterone in human plasma. METHODS: Protein precipitation was used for sample preparation with deuterated progesterone as the internal standard. Chromatographic separation was performed on an ACQUITY C18 column using gradient elution with 0.1% formic acid in water and acetonitrile at a flow rate of 0.3&#xa0;mL/min. Mass spectrometry was operated in positive electrospray ionization mode with multiple reaction monitoring. Instead of using analyte-stripped matrix or surrogate matrix, authentic plasma was directly used for all validation experiments. Quantitation was achieved by subtracting the background signal, and results were compared with those from the classical method using stripped matrix. RESULTS: Excellent linearity was achieved over 0.1-100&#xa0;ng/mL (R2&#xa0;&#x2265;&#xa0;0.99). Precision, accuracy, recovery, matrix effect, and stability all met FDA and ICH M10 acceptance criteria. Compared with the classical method, the bias in Cmax and AUC0-t was within &#xb1;15%, indicating no significant difference between the two methods. CONCLUSION: The direct background subtraction method avoids laborious preparation of blank matrix, eliminates matrix effect discrepancies, and is simple, efficient, and low-cost. It can serve as a general strategy for endogenous substance determination.

Humans

Driven toward care, avoiding the end: A systematic review and meta-analysis of the relationship between death anxiety and healthcare utilisation.

Both overuse and underuse of the healthcare system have been recognised as significant problems. Relatedly, growing research has recognised the key role of death anxiety in driving various health-relevant behaviours. However, the relationship between death anxiety and healthcare utilisation has not yet been systematically explored. The current systematic review and meta-analysis addressed this gap. In total, 987 papers were screened for inclusion, of which 63 were included in the final review (Ntotal&#x202f;=&#x202f;21,271). This included 33 quantitative studies, 27 qualitative studies and 3 mixed-methods designs. In total, 17 studies contained sufficient data to be meta-analysed. Overall, the included studies highlighted a significant relationship between death anxiety and healthcare utilisation; in particular, positive associations with desire for life-prolonging treatments and contact with hospitals and medical professionals. By contrast, a negative association was found with other aspects of healthcare utilisation, including hospice use and end-of-life communication. The sample type emerged as a significant moderator, suggesting that the relationship between death anxiety and healthcare usage was strongest in non-medical samples. The current findings suggest that death anxiety plays a key role in utilisation of the healthcare system. The fear of death may need to be targeted in psychological interventions, in order to ensure maximal effectiveness of health services, and improve outcomes for healthcare users.

Humans

Pcgf5 controls the exit from totipotency in mouse embryonic stem cells.

Mouse embryonic stem cell (ESC) cultures contain a rare subpopulation of two-cell-like cells (2CLCs) that transiently reactivate a two-cell embryo-like transcriptional program characteristic of zygotic genome activation (ZGA), including the endogenous retrovirus MERVL and Zscan4, and thereby regain a totipotent-like state. Polycomb repressive complex 1 (PRC1)-mediated H2AK119ub1 has been implicated in restraining entry into the 2C-like state through Pcgf6, yet the factors governing exit from this state and loss of totipotency remain poorly defined. Here, we show that among the six Pcgf paralogs, Pcgf5, which is most prominently upregulated in 2CLCs and forms an MERVL-driven chimeric transcript (Pcgf5MT2C_Mm) during ZGA in 2-cell embryos, controls exit from the 2C-like state in mouse ESCs. Using a reporter ESC line carrying MERVL-tdTomato and Zscan4c-EGFP (MtZG), we manipulated Pcgf5 dosage bidirectionally. Doxycycline (Dox)-inducible overexpression (OE) of Pcgf5 reduced the double-positive (DP) 2C-like population. Conversely, CRISPR-mediated knockout (KO) of Pcgf5 by targeting a common exon shared by all Pcgf5 variants (hereafter, total Pcgf5) increased the DP population. Time-lapse imaging directly confirmed that these changes reflected genuine differences in duration of the 2C-like state: OE shortened, whereas KO prolonged, the time cells spent in this state. These findings reveal that a Polycomb group factor controls not only entry into but also exit from the 2C-like state.

Animals

Inducible flocculation in Komagataella phaffii enables enhanced biomass separation for biopharmaceutical production.

Biomass separation represents a critical bottleneck in Komagataella phaffii-based biopharmaceutical processes, as typically high cell densities of 40 - 50&#x202f;% create significant operational, technical and economic challenges for harvest operations. Yeast cell aggregation (flocculation) provides a solution to accelerate cell sedimentation by increasing particle size, thus allowing to improve biomass-supernatant separation efficiency during both natural gravity settling and (continuous) centrifugation operations. This study demonstrates successful engineering of K. phaffii strains with an inducible flocculation phenotype using CRISPR/Cas9-based genome editing to integrate the Saccharomyces cerevisiae FLO1 (ScFLO1) gene under control of various regulatory elements, including methanol-inducible and derepressible promoters. Flocculation strength could be enhanced by implementing transcriptional positive feedback circuits based on the methanol-inducible AOX1 promoter. To address methanol-free production requirements, we developed alternative systems to retrofit PAOX1-based ScFLO1 expression and exploited the derepressible PDF promoter, offering broader compatibility with biopharmaceutical manufacturing facilities. Flocculating cells cultivated in a bioreactor demonstrated significantly improved sedimentation behavior, with considerably lower supernatant turbidity after short low-speed centrifugation or gravity sedimentation compared to non-flocculating controls. Crucially, cell flocculation had no negative impact on product amount and quality when expressing a multivalent NANOBODY&#xae; VHH molecule with pharmaceutical relevance. Thus, this work establishes the first genetically engineered flocculation system in K. phaffii compatible with recombinant protein production, providing the basis for an innovative approach to streamline harvest operations in biopharmaceutical processes.

Flocculation