Biology subjects

Chatterjee, A.

Publications and source records attributed to Chatterjee, A..

At least 127 records · Page 7Linked to original sources

bioRxiv2019

Transcriptome-based design of antisense inhibitors re-sensitizes CRE E. coli to carbapenems

Carbapenems are a powerful class of antibiotics, often used as a last-resort treatment to eradicate multidrug-resistant infections. In recent years, however, the incidence of carbapenem-resistant Enterobacteriaceae (CRE) has risen substantially, and the study of bacterial resistance mechanisms has become increasingly important for antibiotic development. Although much research has focused on genomic contributors to carbapenem resistance, relatively few studies have examined CRE pathogens through changes in gene expression. In this research, we used transcriptomics to study a CRE Escherichia coli clinical isolate that is sensitive to meropenem but resistant to ertapenem, to both explore carbapenem resistance and identify novel gene knockdown targets for carbapenem re-sensitization. We sequenced total and small RNA to analyze gene expression changes in response to treatment with ertapenem or meropenem, as compared to an untreated control. Significant expression changes were found in genes related to motility, maltodextrin metabolism, the formate hydrogenlyase complex, and the general stress response. To validate these transcriptomic findings, we used our labs Facile Accelerated Specific Therapeutic (FAST) platform to create antisense peptide nucleic acids (PNA), gene-specific molecules designed to inhibit protein translation. FAST PNA were designed to inhibit the pathways identified in our transcriptomic analysis, and each PNA was then tested in combination with each carbapenem to assess its effect on the antibiotics minimum inhibitory concentrations. We observed significant treatment interaction with five different PNAs across six PNA-antibiotic combinations. Inhibition of the genes hycA, dsrB, and bolA were found to re-sensitize CRE E. coli to carbapenems, whereas inhibition of the genes flhC and ygaC was found to confer added resistance. Our results identify new resistance factors that are regulated at the level of gene expression, and demonstrate for the first time that transcriptomic analysis is a potent tool for designing antibiotic PNA.

microbiology↗

bioRxiv2019

Parallel genomics uncover novel enterococcal-bacteriophage interactions

Bacteriophages (phages) have been proposed as alternative therapeutics for the treatment of multidrug resistant bacterial infections. However, there are major gaps in our understanding of the molecular events in bacterial cells that control how bacteria respond to phage predation. Using the model organism Enterococcus faecalis, we employed two distinct genomic approaches, transposon (Tn) library screening and RNA sequencing, to investigate the interaction of E. faecalis with a virulent phage. We discovered that a transcription factor encoding a LytR family response regulator controls the expression of enterococcal polysaccharide antigen (epa) genes that are involved in phage infection and bacterial fitness. In addition, we discovered that DNA mismatch repair mutants rapidly evolve phage adsorption deficiencies, underpinning a molecular basis for epa mutation during phage infection. Transcriptomic profiling of phage infected E. faecalis revealed broad transcriptional changes influencing viral replication and progeny burst size. We also demonstrate that phage infection alters the expression of bacterial genes associated with intra and inter-bacterial interactions, including genes involved in quorum sensing and polymicrobial competition. Together our results suggest that phage predation has the potential to influence complex microbial behavior and may dictate how bacteria respond to external environmental stimuli. These responses could have collateral effects (positive or negative) on microbial communities such as the host microbiota during phage therapy. ImportanceWe lack fundamental understanding of how phage infection influences bacterial gene expression and consequently how bacterial responses to phage infection affect the assembly of polymicrobial communities. Using parallel genomic approaches, we have discovered novel transcriptional regulators and metabolic genes that influence phage infection. The integration of whole genome transcriptomic profiling during phage infection has revealed the differential regulation of genes important for group behaviors and polymicrobial interactions. Our work suggests that therapeutic phages could more broadly influence bacterial community composition outside of their intended host targets.

microbiology↗

bioRxiv2019

Facile Accelerated Specific Therapeutic (FAST) Platform to Counter Multidrug-Resistance Bacteria

Multidrug-resistant (MDR) bacteria pose a grave concern to global health. This problem is further aggravated by a lack of new and effective antibiotics and countermeasure platforms that can sustain the creation of novel antimicrobials in the wake of new outbreaks or evolution of resistance to antibiotics. To address this, we have developed a Facile Accelerated Specific Therapeutic (FAST) platform that can develop effective therapies against MDR bacteria within a week. Our FAST platform combines four essential modules- design, build, test, and delivery-of drug development cycle. The design module comprises a bioinformatics toolbox that predicts sequence-specific peptide nucleic acids (PNAs) that target non-traditional pathways and genes of bacteria in minutes. The build module constitutes in-situ synthesis and validation of selected PNAs in less than four days and efficacy testing within a day. As a proof of concept, these PNAs were tested against MDR clinical isolates. Here we tested Enterobacteriaceae including carbapenem-resistant Escherichia coli, extended-spectrum beta-lactamase (ESBL) Klebsiella pneumoniae, New Delhi Metallo-beta-lactamase-1 carrying Klebsiella pneumoniae and MDR Salmonella enterica. PNAs showed significant growth inhibition for 82% of treatments, with nearly 18% of the treatments leading to more than 97% decrease. Further, these PNAs are capable of potentiating antibiotic activity in the clinical isolates despite presence of cognate resistance genes. Finally, FAST offers a novel delivery approach to overcome limited transport of PNAs into mammalian cells to clear intracellular infections. This method relies on repurposing the bacterial Type III secretion system in conjunction with a kill switch that is effective at eliminating 99.6% of an intracellular Salmonella infection in human epithelial cells. Our findings demonstrate the potential of the FAST platform in treating MDR bacteria in a rapid and effective manner.

bioengineering↗

bioRxiv2019

Structural robustness affects the engineerability of aminoacyl-tRNA synthetases for genetic code expansion

The ability to engineer the substrate specificity of natural aminoacyl-tRNA synthetase/tRNA pairs facilitates the site-specific incorporation of noncanonical amino acids (ncAAs) into proteins. The Methanocaldococcus jannaschii derived tyrosyl-tRNA synthetase (MjTyrRS)/tRNA pair has been engineered to incorporate numerous ncAAs into protein expressed in bacteria. However, it cannot be used in eukaryotic cells due to cross-reactivity with its host counterparts. The E. coli derived tyrosyl-tRNA synthetase (EcTyrRS)/tRNA pair offers a suitable alternative to this end, but a much smaller subset of ncAAs has been genetically encoded using this pair. Here we report that this discrepancy, at least partly, stems from the lower structural robustness of EcTyrRS relative to MjTyrRS. We show that engineered TyrRS mutants in general exhibit significantly lower thermostability relative to their wild-type counterparts. Derived from a thermophilic archaeon, MjTyrRS is a remarkably sturdy protein and tolerates extensive active site engineering without a catastrophic loss of stability at physiological temperature. In contrast, EcTyrRS exhibits significantly lower thermostability, rendering some of its engineered mutants insufficiently stable at physiological temperature. Our observations identify the structural robustness of an aaRS as an important factor that significantly influences how extensively it can be engineered. To overcome this limitation, we have further developed chimeras between EcTyrRS and its homolog from a thermophilic bacteria, which offer an optimal balance between thermostability and activity. We show that the chimeric bacterial TyrRSs show enhanced tolerance for destabilizing active site mutations, providing a potentially more engineerable platform for genetic code expansion.

synthetic biology↗

bioRxiv2019

Generation of Recombinant Mammalian Selenoproteins through Genetic Code Expansion with Photocaged Selenocysteine

Selenoproteins contain the amino acid selenocysteine and are found in all domains of life. The functions of many selenoproteins are poorly understood, partly due to difficulties in producing recombinant selenoproteins for cell-biological evaluation. Endogenous mammalian selenoproteins are produced through a non-canonical translation mechanism requiring suppression of the UGA stop codon, and a selenocysteine insertion sequence (SECIS) element in the 3 untranslated region of the mRNA. Here, recombinant selenoproteins are generated in mammalian cells through genetic code expansion, circumventing the requirement for the SECIS element, and selenium availability. An engineered orthogonal E. coli leucyl-tRNA synthetase/tRNA pair is used to incorporate a photocaged selenocysteine (DMNB-Sec) at the UAG amber stop codon. Recombinantly expressed selenoproteins can be photoactivated in living cells with spatial and temporal control. Using this approach, the native selenoprotein methionine-R-sulfoxide reductase 1 is generated and activated in mammalian cells. The ability to site-specifically introduce selenocysteine directly in mammalian cells, and temporally modulate selenoprotein activity, will aid in the characterization of mammalian selenoprotein function.

biochemistry↗

bioRxiv2019

Potentiating antibiotic treatment using fitness-neutral gene expression perturbations

The rapid proliferation of multidrug-resistant (MDR) bacteria poses a critical threat to human health, for which new antimicrobial strategies are desperately needed. Here we outline a strategy for combating bacterial infections by administering fitness neutral gene expression perturbations as co-therapies to potentiate antibiotic lethality. We systematically explored the fitness of 270 gene knockout-drug combinations in Escherichia coli, identifying 114 synergistic interactions. Genes revealed in this screen were subsequently perturbed at the transcriptome level via multiplexed CRISPR-dCas9 interference to induce antibiotic synergy. These perturbations successfully sensitized E. coli to antibiotic treatment without imposing a separate fitness cost. We next administered these fitness neutral gene perturbations as co-therapies to potentiate antibiotic killing of Salmonella enterica in intracellular infections of HeLa epithelial cells, demonstrating therapeutic applicability. Finally, we utilized these results to design peptide nucleic acid (PNA) co-therapies for targeted gene expression reduction in four MDR, clinically isolated bacteria. Two isolates of Klebsiella pneumoniae and E. coli were each exposed to PNAs targeting homologs of the genes csgD, fnr, recA and acrA in the presence of sub-minimal inhibitory concentrations of trimethoprim. We successfully increased each strains susceptibility to trimethoprim treatment and identified eight cases in which re-sensitization occurred without a direct fitness impact of the PNA on MDR strains. Our results highlight a promising approach for combating MDR bacteria which could extend the utility of our current antibiotic arsenal.

synthetic biology↗

bioRxiv2019

Construction of two-input logic gates using Transcriptional Interference

Transcriptional Interference (TI) has been shown to regulate gene expression at the DNA level via different molecular mechanisms. The obstacles present on the DNA that a transcribing RNA Polymerase might encounter, e.g. a DNA-bound protein or another RNA Polymerase, can result in TI causing termination of transcription, thus reducing gene expression. However, the potential of TI as a new strategy to engineer complex gene expression modules has not been fully explored yet. Here we created a series of two-input devices using the presence of a roadblocking protein using both experimental and mathematical modeling approaches. We explore how multiple characteristics affect the response of genetic devices engineered to act like either AND, OR, or Single Input logic gates. We show that the dissociation constant of the roadblocking protein, inducer activation of promoter and operator sites, and distance between tandem promoters tune gate behavior. This work highlights the potential of rationally creating different types of genetic responses using the same transcription factors in subtly different genetic architectures.

synthetic biology↗

bioRxiv2019

Stress fiber growth and remodeling determines cellular morphomechanics under uniaxial cyclic stretch

Stress fibers in the cytoskeleton are essential in maintaining cellular shape, and influence their adhesion and migration. Cyclic uniaxial stretching results in cellular reorientation orthogonal to the applied stretch direction via a strain avoidance reaction; the mechanistic cues in cellular mechanosensitivity to this response are currently underexplored. We show stretch induced stress fiber lengthening, their realignment and increased cortical actin in fibroblasts stretched over varied amplitudes and durations. Higher amounts of actin and alignment of stress fibers were accompanied with an increase in the effective elastic modulus of cells. Microtubules did not contribute to the measured stiffness or reorientation response but were essential to the nuclear reorientation. We modeled stress fiber growth and reorientation dynamics using a nonlinear, orthotropic, fiber-reinforced continuum representation of the cell. The model predicts the observed fibroblast morphology and increased cellular stiffness under uniaxial cyclic stretch. These studies are important in exploring the differences underlying mechanotransduction and cellular contractility under stretch.

biophysics↗

bioRxiv2019

Deciphering the mechanoresponsive role of β-catenin in Keratoconus epithelium

Keratoconus (KC) a disease with established biomechanical instability of the corneal stroma, is an ideal platform to identify key proteins involved in mechanosensing. This study aims to investigate the possible role of {beta}-catenin as mechanotransducer in KC epithelium. KC patients were graded as mild, moderate or severe using Amsler Krumeich classification. Immunoblotting and tissue immunofluorescence studies were performed on KC epithelium to analyze the expression and localization of {beta}-catenin, E-cadherin, ZO1, -catenin, Cyclin D1, -actinin, RhoA, Rac123. Co-immunoprecipitation (Co-IP) of {beta}-catenin followed by mass spectrometry of mild KC epithelium was performed to identify its interacting partners. This was further validated by using epithelial tissues grown on scaffolds of different stiffness. We observed down regulation of E-cadherin, -catenin, ZO1 and upregulation of Cyclin D1, -actinin and RhoA in KC corneal epithelium. {beta}-catenin Co-IP from mild KC epithelium identified new interacting partners such as StAR-related lipid transfer protein3, Dynamin-1-like protein, Cardiotrophin-1,Musculin, Basal cell adhesion molecule and Protocadherin Fat 1.{beta}-catenin localization was altered in KC which was validated in vitro, using control corneal epithelium grown on different substrate stiffness. {beta}-catenin localization is dependent upon the elastic modulus of the substrate and acts as mechanotransducer by altering its interaction and regulating the barrier function in corneal epithelium.

cell biology↗

bioRxiv2019

Identification of lncRNAs associated with early stage breast cancer and their prognostic implications

Breast cancer is a common malignancy among women with the highest incidence rate worldwide. Dysregulation of long non-coding RNAs occurring in the preliminary stages of breast carcinogenesis is poorly understood. In this study, RNA sequencing was done to identify long non-coding RNA expression profiles associated with early-stage breast cancer. RNA sequencing was done in 6 invasive ductal carcinoma (IDC) tissues along with paired normal tissue samples, 7 ductal carcinoma in situ (DCIS) tissues and 5 apparently normal breast tissues. We identified 375 differentially expressed lncRNAs (DElncRNAs) in IDC tissues compared to paired normal tissues. Antisense transcripts ([~]58%) were the largest subtype among DElncRNAs. About 20% of the 375 DElncRNAs were supported by typical split readings leveraging their detection confidence. Validation was done in n=52 IDC and paired normal tissue by qRT-PCR for the identified targets (ADAMTS9-AS2, EPB41L4A-AS1, WDFY3-AS2, RP11-295M3.4, RP11-161M6.2, RP11-490M8.1, CTB-92J24.3 and FAM83H-AS)1. We evaluated the prognostic significance of DElncRNAs based on TCGA datasets and overexpression of FAM83H-AS1 was associated with patient poor survival. We confirmed that the down-regulation of ADAMTS9-AS2 in breast cancer was due to promoter hypermethylation through in-vitro silencing experiments and pyrosequencing.

cancer biology↗

bioRxiv2019

Bacteriophage resistance alters antibiotic mediated intestinal expansion of enterococci

Enterococcus faecalis is a human intestinal pathobiont with intrinsic and acquired resistance to many antibiotics, including vancomycin. Nature provides a diverse and virtually untapped repertoire of bacterial viruses, or bacteriophages (phages), that could be harnessed to combat multi-drug resistant enterococcal infections. Bacterial phage resistance represents a potential barrier to the implementation of phage therapy, emphasizing the importance of investigating the molecular mechanisms underlying the emergence of phage resistance. Using a cohort of 19 environmental lytic phages with tropism against E. faecalis, we found that these phages require the enterococcal polysaccharide antigen (Epa) for productive infection. Epa is a surface-exposed heteroglycan synthesized by enzymes encoded by both conserved and strain specific genes. We discovered that exposure to phage selective pressure favors mutation in non-conserved epa genes both in culture and in a mouse model of intestinal colonization. Despite gaining phage resistance, epa mutant strains exhibited a loss of resistance to the cell wall targeting antibiotics, vancomycin and daptomycin. Finally, we show that an E. faecalis epa mutant strain is deficient in intestinal colonization, cannot expand its population upon antibiotic-driven intestinal dysbiosis and fails to be efficiently transmitted to juvenile mice following birth. This study demonstrates that phage therapy could be used in combination with antibiotics to target enterococci within a dysbiotic microbiota. Enterococci that evade phage therapy by developing resistance may be less fit at colonizing the intestine and sensitized to vancomycin preventing their overgrowth during antibiotic treatment.

microbiology↗

bioRxiv2019

Multiple quantitative trait loci contribute tolerance to bacterial canker incited by Pseudomonas syringae pv. actinidiae in kiwifruit (Actinidia chinensis)

Pseudomonas syringae pv. actinidiae (Psa) Biovar 3, a virulent, canker-inducing pathogen is an economic threat to the kiwifruit (Actinidia spp.) industry worldwide. The commercially grown diploid (2x) A. chinensis var. chinensis is more susceptible to Psa than tetraploid and hexaploid kiwifruit. However information on the genetic loci modulating Psa resistance in kiwifruit is not available. Here we report mapping of quantitative trait loci (QTLs) regulating tolerance to Psa in a diploid kiwifruit population, derived from a cross between an elite Psa-susceptible Hort16A and a tolerant male breeding parent P1. Using high-density genetic maps and intensive phenotyping, we identified a single QTL for Psa tolerance on Linkage Group (LG) 27 of Hort16A revealing 16-19% phenotypic variance and candidate alleles for susceptibility and tolerance at this loci. In addition, six minor QTLs were identified in P1 on distinct LGs, exerting 4-9% variance. Complete tolerance in the F1 population is attained by additive effects from Hort16A and P1 QTLs providing evidence that divergent genetic pathways fend-off virulent Psa strain. Two different bioassays further identified new QTLs for tissue-specific responses to Psa. Transcriptome analysis of Psa-tolerant and susceptible genotypes in field revealed hallmarks of basal defense and provided candidate RNA-biomarkers for screening Psa tolerance.

plant biology↗

bioRxiv2018

Integrated epigenome, exome and transcriptome analyses reveal molecular subtypes and homeotic transformation in uterine fibroids.

Uterine fibroids are benign myometrial smooth muscle tumors of unknown etiology that when symptomatic are the most common indication for hysterectomy in the USA. We conducted an integrated analysis of fibroids and adjacent normal myometria by whole exome sequencing, Infinium MethylationEPIC array, and RNA-sequencing. Unsupervised clustering by DNA methylation segregated normal myometria from fibroids, and further separated the fibroids into subtypes marked by MED12 mutation, HMGA2 activation (HMGA2hi) and HMGA1 activation (HMGA1hi). Upregulation of HMGA2 expression in HMGA2hi fibroids did not always appear to be dependent on translocation, as has been historically described, and was associated with hypomethylation in the HMGA2 gene body. Furthermore, we found that expression of HOXA13 was highly upregulated in fibroids and that overexpression of HOXA13 in a myometrial cell line induced expression of genes classically associated with uterine fibroids. Transcriptome analyses of the most differentially expressed genes between cervix and myometrium also showed that uterine fibroids and normal cervix clustered together and apart from normal myometria. Together, our integrated analysis shows a role for epigenetic modification in fibroid biology and strongly suggests that homeotic transformation of myometrium cells to a more cervical phenotype is important for the etiology of the disease.

physiology↗

bioRxiv2018

Galectin-1 promotes the invasion of bladder cancer urothelia through their matrix milieu

The progression of carcinoma of the urinary bladder involves migration of cancer epithelia through their surrounding tissue matrix microenvironment. This was experimentally confirmed when a gender- and grade-diverse set of bladder cancer cell lines were cultured in pathomimetic three-dimensional laminin-rich environments. The high-grade cells, particularly female, formed multicellular invasive morphologies in 3D. In comparison, low- and intermediate-grade counterparts showed growth-restricted phenotypes. A proteomic approach combining mass spectrometry and bioinformatics analysis identified the estrogen-driven lactose-binding lectin Galectin-1 (GAL-1) as a putative candidate that could drive this invasion. Expression of LGALS1, the gene encoding GAL-1 showed an association with tumor grade progression in bladder cell lines. Immunohisto- and cyto-chemical experiments suggested greater extracellular levels of GAL-1 in 3D cultures of high-grade bladder cells and cancer tissues. High levels of GAL-1 associated with increased proliferation- and adhesion- of bladder cancer cells when grown on laminin-rich matrices. Pharmacological inhibition and Gal-1 knockdown in high-grade female cells decreased their adhesion to, and viability on, laminin-rich substrata. Higher GAL-1 also correlated with reduced E-cadherin and increased N-cadherin levels in consonance with a mesenchymal-like phenotype that we observed in 3D culture. The inhibition of GAL-1 reversed the stellate invasive phenotype to a more growth-restricted one in high-grade cells embedded within both basement-membrane-like and stromal collagenous matrix scaffolds. Finally, inhibition of GAL-1 specifically altered cell surface sialic acids, suggesting the mechanism by which the levels of GAL-1 may underlie the aggression and poor prognosis of invasive bladder cancer, especially in women.

cancer biology↗

bioRxiv2018

Everyday taxi drivers: Do better navigators have larger hippocampi?

Work with non-human animals and human navigation experts (London taxi drivers) suggests that the size of the hippocampus, particularly the right posterior hippocampus in humans, relates to navigation expertise. Similar observations, sometimes implicating other sections of the hippocampus, have been made for aging populations and for people with neurodegenerative diseases that affect the hippocampus. These data support the hypothesis that hippocampal volume relates to navigation ability. However, the support for this hypothesis is mixed in healthy, young adults, who range widely in their navigation ability. Here, we administered a naturalistic navigation task that measures cognitive map accuracy to a sample of 90 healthy, young adults who also had MRI scans. Using a sequential analysis design with a registered analysis plan, we did not find that navigation ability related to hippocampal volume (total, right only, right posterior only). We conclude that navigation ability in a typical population does not correlate with variations in hippocampal size, and consider possible explanations for this null result.

neuroscience↗

bioRxiv2018

Design of a de novo aggregating antimicrobial peptide and bacterial conjugation delivery system

Traditional antibiotics are reaching obsolescence as a consequence of antibiotic resistance; therefore novel antibiotic approaches are needed. A recent non-traditional approach involves formation of protein aggregates as antimicrobials to disrupt bacterial homeostasis. Previous work on protein aggregates has focused on genome mining for aggregation-prone sequences in bacterial genomes rather than on rational design of aggregating antimicrobial peptides. Here, we use a synthetic biology approach to design an artificial gene encoding the first de novo aggregating antimicrobial peptide. This artificial gene, opaL (overexpressed protein aggregator Lipophilic), disrupts bacterial homeostasis by expressing extremely hydrophobic peptides. When this hydrophobic sequence is disrupted by acidic residues, consequent aggregation and antimicrobial effect decreases. Further, to deliver this artificial gene, we developed a probiotic approach using RK2, a broad host range conjugative plasmid, to transfer opaL from donor to recipient bacteria. We utilize RK2 to mobilize a shuttle plasmid carrying the opaL gene by adding the RK2 origin of transfer. We show that opaL is non-toxic to the donor, allowing for maintenance and transfer since its expression is under control of a promoter with a recipient-specific T7 RNA polymerase. Upon mating of donor and recipient Escherichia coli, we observe selective growth repression in T7 polymerase expressing recipients. This technique could be used to target desired pathogens by selecting pathogen-specific promoters to control opaL expression. This system provides a basis for the design and delivery of novel antimicrobial peptides.\n\nImportanceThe growing threat of antibiotic resistance necessitates new treatment options for bacterial infections that are recalcitrant to traditional antimicrobials. Existing methods usually involve small-molecule compounds which interfere with essential processes in bacterial cells. By contrast, protein aggregates operate by causing widespread disruption of bacterial homeostasis and may provide a new method for combating infections. We used rational design to create and test an aggregating de novo antimicrobial peptide, OpaL. In addition, we employed bacterial conjugation to deliver the opaL gene from donor bacteria to recipient bacteria while using a strain-specific promoter to ensure that OpaL was only expressed in targeted recipients. To the best of our knowledge, this represents the first design for a de novo peptide with aggregation-mediated antimicrobial activity. We envision that OpaLs design parameters could be used in developing a new class of antimicrobial peptides to help treat antibiotic resistant infections.

microbiology↗

bioRxiv2018

UNC-16/JIP3 and UNC-76/FEZ1 limit the density of mitochondria in C. elegans neurons by maintaining the balance of anterograde and retrograde mitochondrial transport

We investigate the role of axonal transport in regulating neuronal mitochondrial density. We show that the density of mitochondria in the touch receptor neuron (TRN) of adult Caenorhabditis elegans is constant. Mitochondrial density and transport are controlled both by the Kinesin heavy chain and the Dynein-Dynactin complex. However, unlike in other models, the presence of mitochondria in C. elegans TRNs depends on Kinesin light chain as well. Mutants in the three C. elegans miro genes do not alter mitochondrial density in the TRNs. Mutants in the Kinesin-1 associated proteins, UNC-16/JIP3 and UNC-76/FEZ1, show increased mitochondrial density and also have elevated levels of both the Kinesin Heavy and Light Chains in neurons. Genetic analyses suggest that, the increased mitochondrial density at the distal end of the neuronal process in unc-16 and unc-76 depends partly on Dynein. We observe a net anterograde bias in the ratio of anterograde to retrograde mitochondrial flux in the neuronal processes of unc-16 and unc-76, likely due to both increased Kinesin-1 and decreased Dynein in the neuronal processes. Our study shows that UNC-16 and UNC-76 indirectly limit mitochondrial density in the neuronal process maintaining a balance in anterograde and retrograde mitochondrial axonal transport.

genetics↗

bioRxiv2018

Making honey bees lie: experimental dissociation of flight experience and dance communication.

Honey bees use their dance to communicate flight distance and direction of a food source to their nest mates in the hive. How bees transpose flight information to generate a corresponding walking (dance) behavior is still unknown. We now present a detailed study of the changes in dance duration of individual bees after shifting feeder distance. Our experiments indicated that most bees needed two or more foraging trips to the new position before showing an updated dance duration. In addition, only a few bees significantly changed dance duration immediately, whereas most bees first produced intermediary durations. Double shift experiments showed that under certain conditions bees do not update dance duration but continued to perform dance duration for the previously visited feeder position. We propose that generation of dance information involves two memory contents one for newly acquired and one for previously stored distance information.\n\nOne Sentence SummaryGeneration of dance information is temporally separated from immediate flight experience and involves two different memory contents.

animal behavior and cognition↗