Publications search

Found 37769 matches. Displaying 1971-1980
Gal A, Saragosti J, Kronauer DJC
Show All Authors

anTraX, a software package for high-throughput video tracking of color-tagged insects

ELIFE 2020 NOV 19; 9(?):? Article e58145
Recent years have seen a surge in methods to track and analyze animal behavior. Nevertheless, tracking individuals in closely interacting, group-living organisms remains a challenge. Here, we present anTraX, an algorithm and software package for high-throughput video tracking of color-tagged insects. anTraX combines neural network classification of animals with a novel approach for representing tracking data as a graph, enabling individual tracking even in cases where it is difficult to segment animals from one another, or where tags are obscured. The use of color tags, a well-established and robust method for marking individual insects in groups, relaxes requirements for image size and quality, and makes the software broadly applicable. anTraX is readily integrated into existing tools and methods for automated image analysis of behavior to further augment its output. anTraX can handle large-scale experiments with minimal human involvement, allowing researchers to simultaneously monitor many social groups over long time periods.
Guilhot R, Fellous S, Cohen JE
Show All Authors

Yeast facilitates the multiplication of Drosophila bacterial symbionts but has no effect on the form or parameters of Taylor's law

PLOS ONE 2020 NOV 23; 15(11):? Article e0242692
Interactions between microbial symbionts influence their demography and that of their hosts. Taylor's power law (TL)-a well-established relationship between population size mean and variance across space and time-may help to unveil the factors and processes that determine symbiont multiplications. Recent studies suggest pervasive interactions between symbionts in Drosophila melanogaster. We used this system to investigate theoretical predictions regarding the effects of interspecific interactions on TL parameters. We assayed twenty natural strains of bacteria in the presence and absence of a strain of yeast using an ecologically realistic set-up with D. melanogaster larvae reared in natural fruit. Yeast presence led to a small increase in bacterial cell numbers; bacterial strain identity largely affected yeast multiplication. The spatial version of TL held among bacterial and yeast populations with slopes of 2. However, contrary to theoretical prediction, the facilitation of bacterial symbionts by yeast had no detectable effect on TL's parameters. These results shed new light on the nature of D. melanogaster's symbiosis with yeast and bacteria. They further reveal the complexity of investigating TL with microorganisms.
Viant C, Weymar GHJ, Escolano A, Chen S, Hartweger H, Cipolla M, Gazumyan A, Nussenzweig MC
Show All Authors

Antibody Affinity Shapes the Choice between Memory and Germinal Center B Cell Fates

CELL 2020 NOV 25; 183(5):1298-1311.e11
Immunological memory is required for protection against repeated infections and is the basis of all effective vaccines. Antibodies produced by memory B cells play an essential role in many of these responses. We have combined lineage tracing with antibody cloning from single B cells to examine the role of affinity in B cell selection into germinal centers (GCs) and the memory B cell compartment in mice immunized with an HIV-1 antigen. We find that contemporaneously developing memory and GC B cells differ in their affinity for antigen throughout the immune response. Whereas GC cells and their precursors are enriched in antigen binding, memory B cells are not. Thus, the polyclonal memory B cell compartment is composed of B cells that were activated during the immune response but whose antigen binding affinity failed to support further clonal expansion in the GC.
Nirody JA, Budin I, Rangamani P
Show All Authors

ATP synthase: Evolution, energetics, and membrane interactions

JOURNAL OF GENERAL PHYSIOLOGY 2020 NOV; 152(11):? Article e201912475
The synthesis of ATP, life's "universal energy currency," is the most prevalent chemical reaction in biological systems and is responsible for fueling nearly all cellular processes, from nerve impulse propagation to DNA synthesis. ATP synthases, the family of enzymes that carry out this endless task, are nearly as ubiquitous as the energy-laden molecule they are responsible for making. The F-type ATP synthase (F-ATPase) is found in every domain of life and has facilitated the survival of organisms in a wide range of habitats, ranging from the deep-sea thermal vents to the human intestine. Accordingly, there has been a large amount of work dedicated toward understanding the structural and functional details of ATP synthases in a wide range of species. Less attention, however, has been paid toward integrating these advances in ATP synthase molecular biology within the context of its evolutionary history. In this review, we present an overview of several structural and functional features of the F-type ATPases that vary across taxa and are purported to be adaptive or otherwise evolutionarily significant: ion channel selectivity, rotor ring size and stoichiometry, ATPase dimeric structure and localization in the mitochondrial inner membrane, and interactions with membrane lipids. We emphasize the importance of studying these features within the context of the enzyme's particular lipid environment. Just as the interactions between an organism and its physical environment shape its evolutionary trajectory, ATPases are impacted by the membranes within which they reside. We argue that a comprehensive understanding of the structure, function, and evolution of membrane proteins-including ATP synthase-requires such an integrative approach.
Rubin BR, Johnson MA, Berman JM, Goldstein E, Pertsovskaya V, Zhou Y, Contoreggi NH, Dyer AG, Gray JD, Waters EM, McEwen BS, Kreek MJ, Milner TA
Show All Authors

Sex and chronic stress alter delta opioid receptor distribution within rat hippocampal CA1 pyramidal cells following behavioral challenges

NEUROBIOLOGY OF STRESS 2020 NOV; 13(?):? Article 100236
Following oxycodone (Oxy) conditioned place preference (CPP), delta opioid receptors (DORs) differentially redistribute in hippocampal CA3 pyramidal cells in female and male rats in a manner that would promote plasticity and opioid-associative learning processes. However, following chronic immobilization stress (CIS), males do not acquire Oxy-CPP and the trafficking of DORs in CA3 pyramidal neurons is attenuated. Here, we examined the subcellular distribution of DORs in CA1 pyramidal cells using electron microscopy in these same cohorts. CPP: Saline (Sal)-females compared to Sal-males have more cytoplasmic and total DORs in dendrites and more DOR-labeled spines. Following Oxy-CPP, DORs redistribute from near-plasmalemma pools in dendrites to spines in males. CIS: Control females compared to control males have more near-plasmalemmal dendritic DORs. Following CIS, dendritic DORs are elevated in the cytoplasm in females and near-plasmalemma in males. CIS plus CPP: CIS Sal-females compared to CIS Sal-males have more DORs on the plasmalemma of dendrites and in spines. After Oxy, the distribution of DORs does not change in either females or males. Conclusion: Following Oxy-CPP, DORs within CA1 pyramidal cells remain positioned in naive female rats to enhance sensitivity to DOR agonists and traffic to dendritic spines in naive males where they can promote plasticity processes. Following CIS plus behavioral enrichment, DORs are redistributed within CA1 pyramidal cells in females in a manner that could enhance sensitivity to DOR agonists. Conversely, CIS plus behavioral enrichment does not alter DORs in CA1 pyramidal cells in males, which may contribute to their diminished capacity to acquire Oxy-CPP.
Gingras RM, Lwin KM, Miller AM, Bretscher A
Show All Authors

Yeast Rgd3 is a phospho-regulated F-BAR-containing RhoGAP involved in the regulation of Rho3 distribution and cell morphology

MOLECULAR BIOLOGY OF THE CELL 2020 NOV 1; 31(23):2570-2582
Polarized growth requires the integration of polarity pathways with the delivery of exocytic vesicles for cell expansion and counterbalancing endocytic uptake. In budding yeast, the myosin-V Myo2 is aided by the kinesin-related protein Smy1 in carrying out the essential Sec4-dependent transport of secretory vesicles to sites of polarized growth. Overexpression suppressors of a conditional myo2 smy1 mutant identified a novel F-BAR (Fes/CIP4 homology-Bin-Amphiphysin-Rvs protein)-containing RhoGAP, Rgd3, that has activity primarily on Rho3, but also Cdc42. Internally tagged Rho3 is restricted to the plasma membrane in a gradient corresponding to cell polarity that is altered upon Rgd3 overexpression. Rgd3 itself is localized to dynamic polarized vesicles that, while distinct from constitutive secretory vesicles, are dependent on actin and Myo2 function. In vitro Rgd3 associates with liposomes in a PIP2-enhanced manner. Further, the Rgd3 C-terminal region contains several phosphorylatable residues within a reported SH3-binding motif. An unphosphorylated mimetic construct is active and highly polarized, while the phospho-mimetic form is not. Rgd3 is capable of activating Myo2, dependent on its phospho state, and Rgd3 overexpression rescues aberrant Rho3 localization and cell morphologies seen at the restrictive temperature in the myo2 smy1 mutant. We propose a model where Rgd3 functions to modulate and maintain Rho3 polarity during growth.
Armstrong J, Hickey G, Diekhans M, Fiddes IT, Novak AM, Deran A, Fang Q, Xie D, Feng SH, Stiller J, Genereux D, Johnson J, Marinescu VD, Alfoldi J, Harris RS, Lindblad-Toh K, Haussler D, Karlsson E, Jarvis ED, Zhang GJ, Paten B
Show All Authors

Progressive Cactus is a multiple-genome aligner for the thousand-genome era

NATURE 2020 NOV 12; 587(7833):246-251
New genome assemblies have been arriving at a rapidly increasing pace, thanks to decreases in sequencing costs and improvements in third-generation sequencing technologies(1-3). For example, the number of vertebrate genome assemblies currently in the NCBI (National Center for Biotechnology Information) database(4) increased by more than 50% to 1,485 assemblies in the year from July 2018 to July 2019. In addition to this influx of assemblies from different species, new human de novo assemblies(5) are being produced, which enable the analysis of not only small polymorphisms, but also complex, large-scale structural differences between human individuals and haplotypes. This coming era and its unprecedented amount of data offer the opportunity to uncover many insights into genome evolution but also present challenges in how to adapt current analysis methods to meet the increased scale. Cactus(6), a reference-free multiple genome alignment program, has been shown to be highly accurate, but the existing implementation scales poorly with increasing numbers of genomes, and struggles in regions of highly duplicated sequences. Here we describe progressive extensions to Cactus to create Progressive Cactus, which enables the reference-free alignment of tens to thousands of large vertebrate genomes while maintaining high alignment quality. We describe results from an alignment of more than 600 amniote genomes, which is to our knowledge the largest multiple vertebrate genome alignment created so far. The Progressive Cactus program can create reference-free alignments of hundreds of large vertebrate genomes efficiently, and is used for the alignment of more than 600 amniote genomes.
Casanova JL, Holtzman DM, Kaech SM, Lanier LL, Nathan CF, Rudensky AY, Tuveson D, Wolchok JD
Show All Authors

Immigration in science

JOURNAL OF EXPERIMENTAL MEDICINE 2020 NOV; 217(11):? Article e20202055
The advance of science is dependent upon collaboration, which does not have a visa attached to it. Indeed, over 40% of all American-based Nobel Prize winners are immigrants, and data from the National Science Foundation show that 49% of postdocs and 29% of science and engineering faculty in the US are foreign-born. However, restrictive new immigration policies in the US have left many scientists deeply concerned about their future and many American-based laboratories worried about attracting the best talent. At JEM, we're celebrating immigration by sharing the experiences of immigrant and nonimmigrant scientists on our editorial board. Alexander Rudensky and Jean-Laurent Casanova give their firsthand perspective on immigrating to the US, while JeddWolchok, Carl Nathan, David Holtzman, Susan Kaech, Lewis Lanier, and David Tuveson reflect on how immigration has affected their laboratories.
Deen B, Saxe R, Kanwisher N
Show All Authors

Processing communicative facial and vocal cues in the superior temporal sulcus

NEUROIMAGE 2020 NOV 1; 221(?):? Article 117191
Facial and vocal cues provide critical social information about other humans, including their emotional and attentional states and the content of their speech. Recent work has shown that the face-responsive region of posterior superior temporal sulcus ("fSTS") also responds strongly to vocal sounds. Here, we investigate the functional role of this region and the broader STS by measuring responses to a range of face movements, vocal sounds, and hand movements using fMRI. We find that the fSTS responds broadly to different types of audio and visual face action, including both richly social communicative actions, as well as minimally social noncommunicative actions, ruling out hypotheses of specialization for processing speech signals, or communicative signals more generally. Strikingly, however, responses to hand movements were very low, whether communicative or not, indicating a specific role in the analysis of face actions (facial and vocal), not a general role in the perception of any human action. Furthermore, spatial patterns of response in this region were able to decode communicative from noncommunicative face actions, both within and across modality (facial/vocal cues), indicating sensitivity to an abstract social dimension. These functional properties of the fSTS contrast with a region of middle STS that has a selective, largely unimodal auditory response to speech sounds over both communicative and noncommunicative vocal nonspeech sounds, and nonvocal sounds. Region of interest analyses were corroborated by a data-driven independent component analysis, identifying face-voice and auditory speech responses as dominant sources of voxelwise variance across the STS. These results suggest that the STS contains separate processing streams for the audiovisual analysis of face actions and auditory speech processing.
Frew JW, Navrazhina K, Grand D, Sullivan-Whalen M, Gilleaudeau P, Garcet S, Ungar J, Krueger JG
Show All Authors

The effect of subcutaneous brodalumab on clinical disease activity in hidradenitis suppurativa: An open-label cohort study

JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY 2020 NOV; 83(5):1341-1348
Background: Hidradenitis suppurativa is an autoinflammatory disorder of keratinization, with dysregulation of T helper type 17 cytokines. Brodalumab is a monoclonal antibody that targets the interleukin (IL) 17 receptor A receptor. Objectives: To assess the safety and tolerability and clinical response at weeks 12 and 24 of brodalumab in moderate to severe HS. Ten participants with no history of inflammatory bowel disease were administered brodalumab 210 mg/1.5 mL subcutaneously at weeks 0, 1, and 2 and every 2 weeks thereafter until week 24. Participants were assessed for adverse events (grade 2/3 adverse events) and clinical response (Hidradenitis Suppurativa Clinical Response [ HiSCR], Sartorius, International Hidradenitis Suppurativa Severity Scoring System [IHS4]), including ultrasonography and skin biopsies. Results: All 10 participants completed the study. No grade 2/3 adverse events associated with the use of brodalumab were reported. All patients (100%) achieved HiSCR, and 80% achieved IHS4 category change at week 12. HiSCR achievement occurred as early as week 2, likely due to the unique blockade of IL-17A, IL-17C, and IL-17F by brodalumab. Significant improvements were seen in pain, itch, quality of life, and depression. Conclusions: Brodalumab was well tolerated in this HS cohort, with no serious adverse events and improvement in clinical outcomes. Alterations in dose frequency may be required in those with advanced disease, which requires further exploration.