Biology subjects

Bai, J.

Publications and source records attributed to Bai, J..

At least 73 records · Page 4Linked to original sources

bioRxiv2022

ACNN-6mA: Prediction of N6-Methyladenine Loci in Multiple Species Based on Rice Dataset Pre-training Model

N6-methyladenine is an epigenetic modification that plays a significant role in various cellular processes. Genome-wide monitoring of methylation sites is conducive to understanding the biological function of methylation. Due to the limitations of traditional dry and wet experiments, a series of machine learning and deep learning methods have been developed to detect methylation sites, but their detection species are single or performance is poor. First of all, we conducted sufficient experiments on the widely studied rice datasets, and compared with the previous research, we have greatly improved in various indicators on the two rice datasets. Then we used the models trained on the rice dataset to fine-tune training in half of the other 11 datasets and predict the other half of the independent datasets. Then we used 11 trained models to test 11 species respectively. It was found that ACNN-6mA could obtain higher AUC, ACC and MCC whether cross-species prediction or independent verification set prediction. ACNN-6mA model and code for follow-up researchers is provided as an open-source tool available at https://github.com/jrebai/ACNN-6mA.

bioinformatics↗

bioRxiv2022

G Protein-Coupled Receptor Kinase-2 (GRK-2) regulates exploration through neuropeptide signaling in Caenorhabditis elegans

Animals alter their behavior in manners that depend on environmental conditions as well as their developmental and metabolic states. For example, C. elegans is quiescent during larval molts or during conditions of satiety. By contrast, worms enter an exploration state when removed from food. Sensory perception influences movement quiescence (defined as a lack of body movement), as well as the expression of additional locomotor states in C. elegans that are associated with increased or reduced locomotion activity, such as roaming (exploration behavior) and dwelling (local search). Here we find that movement quiescence is enhanced, and exploration behavior is reduced in G protein-coupled receptor kinase grk-2 mutant animals. grk-2 was previously shown to act in chemosensation, locomotion, and egg-laying behaviors. Using neuron-specific rescuing experiments, we show that GRK-2 acts in multiple ciliated chemosensory neurons to control exploration behavior. grk-2 acts in opposite ways from the cGMP-dependent protein kinase gene egl-4 to control movement quiescence and exploration behavior. Analysis of mutants with defects in ciliated sensory neurons indicates that grk-2 and the cilium-structure mutants act in the same pathway to control exploration behavior. We find that GRK-2 controls exploration behavior in an opposite manner from the neuropeptide receptor NPR-1 and the neuropeptides FLP-1 and FLP-18. Finally, we show that secretion of the FLP-1 neuropeptide is negatively regulated by GRK-2 and that overexpression of FLP-1 reduces exploration behavior. These results define neurons and molecular pathways that modulate movement quiescence and exploration behavior. Author summaryMany modulatory neurotransmitters affect behavior by binding to G protein-coupled receptors (GPCRs) and initiating signals that modify neuronal activity. GPCRs are regulated by G protein-coupled receptor kinases (GRKs). GRKs phosphorylate and promote the inactivation of GPCRs. Here we identify GRK-2 as a regulator of distinct locomotor states in C. elegans. We find that GRK-2 acts in olfactory sensory neurons to promote exploration and suppress movement quiescence. Additionally, we show that GRK-2 acts in opposition to a neuropeptide signaling pathway that acts in interneurons. Thus, this study demonstrates critical roles for GRK-2 in regulating neuromodulatory signaling and locomotor behavior.

genetics↗

bioRxiv2022

Genome-wide phage susceptibility analysis in Acinetobacter baumannii reveals capsule modulation as a central determinant of phage defense

Phage have gained renewed interest as an adjunctive treatment for life-threatening infections with the resistant nosocomial pathogen Acinetobacter baumannii. Our understanding of how A. baumannii defends against phage remains limited, although this information could lead to improved antimicrobial therapies. To address this problem, we identified genome-wide determinants of phage susceptibility in A. baumannii using Tn-seq. These studies focused on the lytic phage Loki, which targets Acinetobacter by unknown mechanisms. We identified 41 candidate loci that increase susceptibility to Loki when disrupted, and 10 that decrease susceptibility. Combined with spontaneous resistance mapping, our results support the model that Loki uses the K3 capsule as an essential receptor, and that capsule modulation provides A. baumannii with strategies to control vulnerability to phage. A key center of this control is transcriptional regulation of capsule synthesis and phage virulence by the global regulator BfmRS. Mutations hyperactivating BfmRS simultaneously increase capsule levels, Loki replication, and host killing, while BfmRS-inactivating mutations have the opposite effect, reducing capsule and blocking Loki infection. We identified novel BfmRS-activating mutations, including knockouts of a T2 RNase protein and the disulfide formation enzyme DsbA, that hypersensitize bacteria to phage challenge. We further found that mutation of a glycosyltransferase known to alter capsule structure and bacterial virulence can also cause complete phage resistance. Finally, additional factors including lipooligosaccharide and Lon protease act independently of capsule modulation to interfere with Loki infection. This work demonstrates that regulatory and structural modulation of capsule, known to alter A. baumannii virulence, is also a major determinant of susceptibility to phage. Author SummaryAntibiotic-resistant infections with Acinetobacter baumannii are a major problem in critical care units and have increased in frequency during the COVID-19 pandemic. The virulence of these infections depends on a polysaccharide capsule surrounding the bacterium. Phage, or viruses that kill bacteria, represent a promising alternative therapy against highly antibiotic-resistant A. baumannii infections, and A. baumannii-specific phage often target the capsule. Here, we use high-throughput genetics to analyze how A. baumannii defends against phage and identify ways to potentiate their killing activity. We found that stressing the bacteria in ways that cause augmented production of capsule also causes hyper-susceptibility to phage. By contrast, turning off the stress response, or mutating the capsule structure, causes complete phage resistance. Altering another surface structure, lipooligosaccharide, or an intracellular protease also enhances phage attack. Modulating the amounts or makeup of capsular polysaccharide is known to influence virulence in A. baumannii. This work thus uncovers a connection between phage pressure and the evolution of virulence in A. baumannii, and it identifies control mechanisms that may be leveraged for improving future phage-based antimicrobial therapies.

microbiology↗

bioRxiv2022

Histopathological characteristics of different parts of surgical specimens of UPJ stenosis

ObjectiveTo observe the pathological changes of different anatomical sites in the specimens obtained from ureteropelvic junction obstruction (UPJO) caused by UPJ stenosis. Materials and MethodsA total of 34 cases of UPJO were performed. The lesion of the ureteropelvic junction was visualized as the center, the 1.5cm renal pelvis segment was taken along the upper edge of the lesion segment (as the control group). Along the lower edge of the ureteral stricture, 1cm of ureteral stricture tissue was taken downward. Different dyeing methods were used to observe the tissue arrangement of different parts, the ratio of muscle to fiber tissue and the distribution of interstitial cells of Cajal(ICC) . ResultsThe number of ICCs in the lesion segment was reduced or even absent, disordered arrangement of muscle tissue was seen, the fibrous tissue proliferated to varying degrees. The pathological changes were statistically different from those of normal segment and ureteral stricture segment. ConclusionThe decrease of ICCs cells and the degree of tissue fibrosis are closely related to the pathogenesis and disease progression of UPJO caused by UPJ stenosis.

developmental biology↗

bioRxiv2022

Cross-amplified Barcodes on Slides for Spatial Transcriptomics Sequencing

Spatial transcriptomics can reveal molecular signatures of tissue at spatial scales, but current technologies cannot integrate excellent accessibility and easy data-decoding. Here, we use oligonucleotides whose number is the square root of the number of spots to generate cross-amplified spatial barcodes on slides using microfluidic technology. This method can obtain microarrays with well-defined barcodes easily and at low cost, without post-decoding, which contributes to the popularization of spatial transcriptomics.

genomics↗

bioRxiv2022

ILnc: Prioritizing Long Non-coding RNAs for Pan-cancer Analysis of Immune Cell Infiltration

The distribution and extent of immune cell infiltration into solid tumors play pivotal roles in cancer immunology and therapy. Here we introduced an immune long non-coding RNA (lncRNA) signature-based method (ILnc), for estimating the abundance of 14 immune cell types from lncRNA transcriptome data. Performance evaluation through pure immune cell data shows that our lncRNA signature sets can be more accurate than protein-coding gene signatures. We found that lncRNA signatures are significantly enriched to immune functions and pathways, such as immune response and T cell activation. In addition, the expression of these lncRNAs is significantly correlated with expression of marker genes in corresponding immune cells. Application of ILnc in 33 cancer types provides a global view of immune infiltration across cancers and we found that the abundance of most immune cells is significantly associated with patient clinical signatures. Finally, we identified six immune subtypes spanning cancer tissue types which were characterized by differences in immune cell infiltration, homologous recombination deficiency (HRD), expression of immune checkpoint genes, and prognosis. Altogether, these results demonstrate that ILnc is a powerful and exhibits broad utility for cancer researchers to estimate tumor immune infiltration, which will be a valuable tool for precise classification and clinical prediction.

bioinformatics↗

bioRxiv2022

Caveolae promote successful abscission by controlling intercellular bridge tension during cytokinesis

During cytokinesis, the intercellular bridge (ICB) connecting the daughter cells experiences pulling forces, which delay abscission by preventing the assembly of the ESCRT scission machinery. Abscission is thus triggered by tension release, but how ICB tension is controlled is unknown. Here, we report that caveolae, which are known to control membrane tension upon mechanical stress in interphase cells, are located at the midbody, at the abscission site and at the ICB/cell interface in dividing cells. Functionally, the loss of caveolae delays ESCRT-III recruitment during cytokinesis and impairs abscission. This is the consequence of a 2-fold increase of ICB tension measured by laser ablation, associated with a local increase in myosin II activity at the ICB/cell interface. We thus propose that caveolae buffer membrane tension and limit contractibility at the ICB to promote ESCRT-III assembly and cytokinetic abscission. Altogether, this work reveals an unexpected connection between caveolae and the ESCRT machinery and the first role of caveolae in cell division. TEASERCaveolae limit the tension in the intercellular bridge during cytokinesis to enable ESCRT-III assembly and successful abscission.

cell biology↗

bioRxiv2021

Chemical Reversible Crosslinking Enables Measurement of RNA 3D Distances and Alternative Conformations in Cells

Three-dimensional (3D) structures dictate the functions of RNA molecules in a wide variety of biological processes. However, direct determination of RNA 3D structures in vivo is difficult due to their large sizes, conformational heterogeneity, and dynamics. Here we present a new method, Spatial 2-Hydroxyl Acylation Reversible Crosslinking (SHARC), which uses chemical crosslinkers of defined lengths to measure distances between nucleotides in cellular RNA. Integrating crosslinking, exonuclease (exo) trimming, proximity ligation, and high throughput sequencing, SHARC enables transcriptome-wide tertiary structure contact maps at high accuracy and precision, revealing heterogeneous RNA structures and interactions. SHARC data provide constraints that improves Rosetta-based RNA 3D structure modeling at near-nanometer resolution. Integrating SHARC-exo with other crosslinking-based methods, we discover compact folding of the 7SK RNA, a critical regulator of transcriptional elongation. These results establish a new strategy for measuring RNA 3D distances and alternative conformations in their native cellular context.

biochemistry↗

bioRxiv2021

SCARECROW maintains the stem cell niche in Arabidopsis root by ensuring telomere integrity

Stem cells are the ultimate source of the cells in various tissues and organs, and thus are essential to postembryonic plant growth and development. SCARECROW (SCR) is a plant-specific transcription regulator well known for its role in stem-cell renewal in plant roots, but the mechanism by which SCR exerts this function is still unclear. To address this question, we carried out a genetic screen for mutants that no longer express SCR in the stem-cell niche in the Arabidopsis root, and one of the mutants is characterized herein. Using marker-assisted mapping, whole genome sequencing, and complementation tests, we pinpointed the causal mutation in this mutant at TEN1, which encodes telomere-end protecting factor. By sequence alignment of TEN1 homologs in a wide range of eukaryotes, we identified two novel motifs. The importance of these motifs was examined through site-directed mutagenesis of a conserved amino acid, and through complementation tests, which showed that G100 is required for TEN1 stability. Interestingly, we found that TEN1 expression was dramatically reduced in the scr mutant. Two components in the same protein complex as TEN1, STN1 and CTC1, were found to be also dramatically downregulated in scr, as well as telomerase. Further studies showed that loss of STN1, CTC1 and telomerase also caused defects in the root stem cells. In line with these findings, the scr mutant was hypersensitive to DNA damage reagents such as Zeocin. These results together suggest that SCR maintains root stem cells by promoting expression of genes that ensures genome integrity. One sentence summaryThis study reveals a role for the root development regulator SCARECROW in maintaining the expression of telomere-end protecting factors and a connection between genome integrity and stem-cell maintenance in Arabidopsis root.

plant biology↗

bioRxiv2021

The endophilin curvature-sensitive motif requires electrostatic guidance to recycle synaptic vesicles in vivo

Curvature-sensing mechanisms assist proteins in executing particular actions on various membrane organelles. Here, we investigated the functional specificity of curvature-sensing amphipathic motifs through the study of endophilin, an endocytic protein for synaptic vesicle recycling. We generated chimeric endophilin proteins by replacing the endophilin amphipathic motif H0 with other curvature-sensing amphipathic motifs. We found that the role of amphipathic motifs cannot simply be extrapolated from the identity of their parental proteins. For example, the amphipathic motif of the nuclear pore complex protein NUP133 functionally replaced the synaptic role of endophilin H0. Interestingly, non-functional endophilin chimeras had similar defects - producing fewer synaptic vesicles but more endosomes - indicating that the curvature-sensing motifs in these chimeras have a common deficiency at reforming synaptic vesicles. Finally, we converted non-functional endophilin chimeras into functional proteins by changing the cationic property of amphipathic motifs, setting a precedent for reprogramming the functional specificity of curvature-sensing motifs in vivo.

cell biology↗

bioRxiv2021

ShareLoc - an open platform for sharing localization microscopy data

Novel insights and more powerful analytical tools can emerge from the reanalysis of existing data sets, especially via machine learning methods. Despite the widespread use of single molecule localization microscopy (SMLM) for super-resolution bioimaging, the underlying data are often not publicly accessible. We developed ShareLoc (https://shareloc.xyz), an open platform designed to enable sharing, easy visualization and reanalysis of SMLM data. We discuss its features and show how data sharing can improve the performance and robustness of SMLM image reconstruction by deep learning.

bioinformatics↗

bioRxiv2021

Classification and clustering of RNA crosslink-ligation data reveal complex structures and homodimers

The recent development and application of methods based on the general principle of "crosslinking and proximity ligation" (crosslink-ligation) are revolutionizing RNA structure studies in living cells. However, extracting structure information from such data presents unique challenges. Here we introduce a set of computational tools for the systematic analysis of data from a wide variety of cross-link-ligation methods, specifically focusing on read mapping, alignment classification and clustering. We design a new strategy to map short reads with irregular gaps at high sensitivity and specificity. Analysis of previously published data reveals distinct properties and bias caused by the crosslinking reactions. We perform rigorous and exhaustive classification of alignments and discover 8 types of arrangements that provide distinct information on RNA structures and interactions. To deconvolve the dense and inter-twined gapped alignments, we develop a network/graph-based tool CRSSANT (Crosslinked RNA Secondary Structure Analysis using Network Techniques), which enables clustering of gapped alignments and discovery of new alternative and dynamic conformations. We discover that multiple crosslinking and ligation events can occur on the same RNA, generating multi-segment alignments to report complex high level RNA structures and multi-RNA interactions. We find that alignments with overlapped segments are produced from potential homodimers and develop a new method for their de novo identification. Analysis of overlapping alignments revealed potential new homodimers in cellular noncoding RNAs and RNA virus genomes in the Picornaviridae family. Together, this suite of computational tools enables rapid and efficient analysis of RNA structure and interaction data in living cells.

bioinformatics↗

bioRxiv2021

The northern gene flow into southeastern East Asians inferred from genome-wide array genotyping

The population history of Southeast China remains poorly understood due to the sparse sampling of present-day populations and far less modeling with ancient genomic data. We here newly reported genome-wide genotyping data from 207 present-day Han Chinese and Hmong-Mien-speaking She people from Fujian and Taiwan, southeast China. We co-analyzed with 66 early-Neolithic to Iron-Age ancient Fujian and Taiwan individuals obtained from literature to explore the genetic continuity and admixture based on the genetic variations of high-resolution time transect. We found the genetic differentiation between northern and southern East Asians defined by a north-south East Asian genetic cline and the studied southern East Asians were clustered in the southern end of this cline. We also found that southeastern coastal continental modern East Asians harbored the genetic differentiation with other southern Tai-Kadai, Hmong-Mien, Austronesian and Austroasiatic speakers, as well as geographically close Neolithic-to-Iron Age populations, but relatedly close to post-Neolithic Yellow River ancients, which suggested the influence of southward gene flow on the modern southern coastal gene pool. Besides, we also identified one new Hmong-Mien genetic cline in East Asia with the coastal Fujian She localizing at the intersection position between Hmong-Mien and Han clines in the principal component analysis. She people show stronger genetic affinity with southern East Asian indigenous populations with the main ancestry deriving from Hanben-related populations. The southeastern Han Chinese could be modeled with the primary ancestry deriving from the group related to the Yellow River Basin millet farmers and the remaining from groups related to southeastern ancient indigenous rice farmers, which was consistent with the northern China origin of modern southeastern Han Chinese and in line with the historically and archaeologically attested southward migrations of Han people and their ancestors. Interestingly, f4-statistics and three-way admixture model results showed both coastal ancient sources related to Austronesian speakers and inland ancient sources related to Austroasiatic speakers complexed the modern observed fine-scale genetic structure here. Our estimated north-south admixture time ranges based on the decay of the linkage disequilibrium spanned from the Bronze age to historic periods, suggesting the recent large-scale population migrations and subsequent admixture participated in the formation of modern Han in Southeast Asia.

genetics↗

bioRxiv2021

Bioimage postprocessing based on discrete wavelet transform and Lucy-Richardson deconvolution methods

Accompanied with the increasing requirements of probing micro/nanoscopic structures of biological samples, a variety of image processing algorithms have been developed for visualization or to facilitate data analysis. However, it remains challenging to enhance both the signal-to-noise ratio and image resolution using a single algorithm. In this investigation, we propose an approach utilizing discrete wavelet transform (DWT) in combination with Lucy-Richardson (LR) deconvolution (DWDC). Our results demonstrate that the signal-to-noise ratio and resolution of live cells microtubule network are considerably improved, allowing recognition of features as small as 120 nm. Notably, the approach is independent of imaging system and shows robustness in processing fibrous structures, e.g. the cytoskeleton networks.

biophysics↗

bioRxiv2021

Single-Cell Classification Using Graph Convolutional Networks

BackgroundAnalyzing single-cell RNA sequencing (scRNAseq) data plays an important role in understanding the intrinsic and extrinsic cellular processes in biological and biomedical research. One significant effort in this area is the identification of cell types. With the availability of a huge amount of single cell sequencing data and discovering more and more cell types, classifying cells into known cell types has become a priority nowadays. Several methods have been introduced to classify cells utilizing gene expression data. However, incorporating biological gene interaction networks has been proved valuable in cell classification procedures. ResultsIn this study, we propose a multimodal end-to-end deep learning model, named sigGCN, for cell classification that combines a graph convolutional network (GCN) and a neural network to exploit gene interaction networks. We used standard classification metrics to evaluate the performance of the proposed method on the within-dataset classification and the cross-dataset classification. We compared the performance of the proposed method with those of the existing cell classification tools and traditional machine learning classification methods. ConclusionsResults indicate that the proposed method outperforms other commonly used methods in terms of classification accuracy and F1 scores. This study shows that the integration of prior knowledge about gene interactions with gene expressions using GCN methodologies can extract effective features improving the performance of cell classification.

bioinformatics↗

bioRxiv2021

Systematic characterization of short intronic splicing-regulatory elements

Intronic splicing enhancers and silencers (ISEs and ISSs) are two groups of splicing-regulatory elements (SREs) that play critical roles in determining splice-site selection, particularly for alternatively spliced introns or exons. SREs are often short motifs; their mutation or dysregulation of their cognate proteins frequently causes aberrant splicing and results in disease. To date, however, knowledge about SRE sequences and how they regulate splicing remains limited. Here, using an SMN2 minigene, we generated a complete pentamer-sequence library that comprises all possible combinations of 5 nucleotides in intron 7, at a fixed site downstream of the 5' splice site. We systematically analyzed the effects of all 1023 mutant pentamers on exon 7 splicing, in comparison to the wild-type minigene, in HEK293 cells. Our data show that the majority of pentamers significantly affect exon 7 splicing: 584 of them are stimulatory and 230 are inhibitory. To identify actual SREs, we utilized a motif set enrichment analysis (MSEA), from which we identified groups of stimulatory and inhibitory SRE motifs. We experimentally validated several strong SREs in SMN1/2 and MAPT minigene settings. Our results provide a valuable resource for understanding how short RNA sequences regulate splicing. Many novel SREs can be explored further to elucidate their mechanism of action.

molecular biology↗

bioRxiv2021

The United States Swine Pathogen Database: integrating veterinary diagnostic laboratory sequence data to monitor emerging pathogens of swine

Veterinary diagnostic laboratories annually derive thousands of nucleotide sequences from clinical samples of swine pathogens such as porcine reproductive and respiratory syndrome virus (PRRSV), Senecavirus A, and swine enteric coronaviruses. In addition, next generation sequencing has resulted in the rapid production of full-length genomes. Presently, sequence data are released to diagnostic clients for the purposes of informing control measures, but are not publicly available as data may be associated with sensitive information. However, public sequence data can be used to objectively design field-relevant vaccines; determine when and how pathogens are spreading across the landscape; identify virus transmission hotspots; and are a critical component in genomic surveillance for pandemic preparedness. We have developed a centralized sequence database that integrates a selected set of previously private clinical data, using PRRSV data as an exemplar, alongside publicly available genomic information. We implemented the Tripal toolkit, using the open source Drupal content management system and the Chado database schema. Tripal consists of a collection of Drupal modules that are used to manage, visualize, and disseminate biological data stored within Chado. Hosting is provided by Amazon Web Services (AWS) EC2 cloud instance with resource scaling. New sequences sourced from diagnostic labs contain at a minimum four data items: genomic information; date of collection; collection location (state or province level); and a unique identifier. Users can download annotated genomic sequences from the database using a customized search interface that incorporates data mined from published literature; search for similar sequences using BLAST-based tools; and explore annotated reference genomes. Additionally, because the bulk of data presently are PRRSV sequences, custom curation and annotation pipelines have determined PRRSV genotype (Type 1 or 2), the location of open reading frames and nonstructural proteins, generated amino acid sequences, the occurrence of putative frame shifts, and restriction fragment length polymorphism (RFLP) classification of GP5 genes. Genomic data from seven major swine pathogens have been curated and annotated. The resource provides researchers timely access to sequences discovered by veterinary diagnosticians, allowing for epidemiological and comparative virology studies. The result will be a better understanding on the emergence of novel swine viruses in the United States (US), and how these novel strains are disseminated in the US and abroad. Database URLhttps://swinepathogendb.org

bioinformatics↗

bioRxiv2021

Dopamine receptor DOP-1 engages a sleep pathway to modulate swimming in C. elegans

Animals require robust yet flexible programs to support locomotion. While it is clear that a variety of processes must be engaged to ensure rhythmic actions, the exact mechanisms remain largely unknown. Here we report a novel pathway that connects the D1-like dopamine receptor DOP-1 with a sleep mechanism to modulate swimming in C. elegans. We show that DOP-1 plays a negative role in sustaining swimming behavior. By contrast, a pathway through the D2-like dopamine receptor DOP-3 negatively regulates the initiation of swimming, but its impact fades quickly over a few minutes. We find that DOP-1 and the GPCR kinase GRK-2 function in the sleep interneuron RIS, where DOP-1 modulates the secretion of a sleep neuropeptide FLP-11. Our genetic studies further show that DOP-1 and FLP-11 act in the same pathway to modulate swimming. Together, these results delineate a functional connection between a dopamine receptor and a sleep program to regulate swimming in C. elegans. The temporal transition between DOP-3 and DOP-1 pathways highlights the dynamic nature of neuromodulation for rhythmic movements that persist over time. HIGHLIGHTSO_LIThe D1-like dopamine receptor DOP-1 regulates swimming at 10 minutes C_LIO_LIAn integrated function of DOP-1 and DOP-3 is required for the continuity of swimming C_LIO_LIDOP-1 and GRK-2 act in the sleep neuron RIS C_LIO_LIFLP-11, a neuropeptide that promotes sleep, negatively regulates swimming C_LI IN BRIEFXu et al. investigated genetic programs that modulate swimming behavior in the nematode C. elegans. They identified a functional link that couples a D1-like dopamine receptor to a sleep program that modulates the sustained phase rather than the initial phase of swimming.

genetics↗