Most bilaterian animals excrete toxic metabolites through specialized organs, such as nephridia and kidneys, which share morphological and functional similarities and define this major clade as the nephrozoa. In contrast, the excretory mechanisms in other (non-nephrozoan) animals are largely unknown, making the reconstruction of ancestral excretory mechanisms problematic. In this study, Andrikou et al. investigated the excretory mode of members of the Xenacoelomorpha, the sister group to Nephrozoa, and Cnidaria, the sister group to Bilateria. They show that although a cnidarian (a sea anemone) seems to use diffusion as its main excretory mode, two xenacoelomorph animals (an acoel and a nemertodermatid) use both active transport and diffusion mechanisms. The authors propose that digestive-associated tissues functioned as excretory sites before the evolution of specialized organs in nephrozoans. The image shows the localization of the rhesus glycoprotein (an ammonia transporter; magenta) in syncytium-affiliated cells in the gut of the acoel worm Isodiametra pulchra. The image is a projection of merged confocal stacks, also showing microtubules (green) and nuclei (blue). Andrikou et al.
Image Credit: Carmen Andrikou
Essay
Activity patterns in mammals: Circadian dominance challenged
PLOS Biology: published July 15, 2019 | https://doi.org/10.1371/journal.pbio.3000360
Unsolved Mystery
The biology of extracellular vesicles: The known unknowns
PLOS Biology: published July 18, 2019 | https://doi.org/10.1371/journal.pbio.3000363
Community Pages
The Human Brain Project—Synergy between neuroscience, computing, informatics, and brain-inspired technologies
PLOS Biology: published July 1, 2019 | https://doi.org/10.1371/journal.pbio.3000344
True Grit: Passion and persistence make an innovative course design work
PLOS Biology: published July 18, 2019 | https://doi.org/10.1371/journal.pbio.3000359
Research Articles
Uncoordinated maturation of developing and regenerating postnatal mammalian vestibular hair cells
PLOS Biology: published July 1, 2019 | https://doi.org/10.1371/journal.pbio.3000326
A polymorphic helix of a Salmonella needle protein relays signals defining distinct steps in type III secretion
PLOS Biology: published July 1, 2019 | https://doi.org/10.1371/journal.pbio.3000351
Social intolerance is a consequence, not a cause, of dispersal in spiders
PLOS Biology: published July 2, 2019 | https://doi.org/10.1371/journal.pbio.3000319
Human visual cortex is organized along two genetically opposed hierarchical gradients with unique developmental and evolutionary origins
PLOS Biology: published July 3, 2019 | https://doi.org/10.1371/journal.pbio.3000362
Global proteomic analyses define an environmentally contingent Hsp90 interactome and reveal chaperone-dependent regulation of stress granule proteins and the R2TP complex in a fungal pathogen
PLOS Biology: published July 8, 2019 | https://doi.org/10.1371/journal.pbio.3000358
Spermine in semen of male sea lamprey acts as a sex pheromone
PLOS Biology: published July 9, 2019 | https://doi.org/10.1371/journal.pbio.3000332
Novel antibiotics effective against gram-positive and -negative multi-resistant bacteria with limited resistance
PLOS Biology: published July 9, 2019 | https://doi.org/10.1371/journal.pbio.3000337
Macaque anterior cingulate cortex deactivation impairs performance and alters lateral prefrontal oscillatory activities in a rule-switching task
PLOS Biology: published July 11, 2019 | https://doi.org/10.1371/journal.pbio.3000045
A novel Ca2+-binding protein that can rapidly transduce auxin responses during root growth
PLOS Biology: published July 11, 2019 | https://doi.org/10.1371/journal.pbio.3000085
Successful validation of a larval dispersal model using genetic parentage data
PLOS Biology: published July 12, 2019 | https://doi.org/10.1371/journal.pbio.3000380
Delayed death in the malaria parasite Plasmodium falciparum is caused by disruption of prenylation-dependent intracellular trafficking
PLOS Biology: published July 18, 2019 | https://doi.org/10.1371/journal.pbio.3000376
Structural basis for recognition of the tumor suppressor protein PTPN14 by the oncoprotein E7 of human papillomavirus
PLOS Biology: published July 19, 2019 | https://doi.org/10.1371/journal.pbio.3000367
LATS1/2 suppress NFκB and aberrant EMT initiation to permit pancreatic progenitor differentiation
PLOS Biology: published July 19, 2019 | https://doi.org/10.1371/journal.pbio.3000382
Diversification of the type IV filament superfamily into machines for adhesion, protein secretion, DNA uptake, and motility
PLOS Biology: published July 19, 2019 | https://doi.org/10.1371/journal.pbio.3000390
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Widespread selection and gene flow shape the genomic landscape during a radiation of monkeyflowers
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Cooperative population coding facilitates efficient sound-source separability by adaptation to input statistics
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Atg11 tethers Atg9 vesicles to initiate selective autophagy
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Spectral fingerprints or spectral tilt? Evidence for distinct oscillatory signatures of memory formation
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Short Reports
Spectrin-based membrane skeleton supports ciliogenesis
PLOS Biology: published July 12, 2019 | https://doi.org/10.1371/journal.pbio.3000369
Attenuation of chronic antiviral T-cell responses through constitutive COX2-dependent prostanoid synthesis by lymph node fibroblasts
PLOS Biology: published July 15, 2019 | https://doi.org/10.1371/journal.pbio.3000072
Primary cilium loss in mammalian cells occurs predominantly by whole-cilium shedding
PLOS Biology: published July 17, 2019 | https://doi.org/10.1371/journal.pbio.3000381
Active mode of excretion across digestive tissues predates the origin of excretory organs
PLOS Biology: published July 29, 2019 | https://doi.org/10.1371/journal.pbio.3000408
Ancient RNA from Late Pleistocene permafrost and historical canids shows tissue-specific transcriptome survival
PLOS Biology: published July 30, 2019 | https://doi.org/10.1371/journal.pbio.3000166
Methods and Resources
Targeted genetic screening in mice through haploid embryonic stem cells identifies critical genes in bone development
PLOS Biology: published July 2, 2019 | https://doi.org/10.1371/journal.pbio.3000350
Dissecting the transcriptome landscape of the human fetal neural retina and retinal pigment epithelium by single-cell RNA-seq analysis
PLOS Biology: published July 3, 2019 | https://doi.org/10.1371/journal.pbio.3000365
Assembling a plug-and-play production line for combinatorial biosynthesis of aromatic polyketides in Escherichia coli
PLOS Biology: published July 18, 2019 | https://doi.org/10.1371/journal.pbio.3000347
N-terminal β-strand underpins biochemical specialization of an ATG8 isoform
PLOS Biology: published July 22, 2019 | https://doi.org/10.1371/journal.pbio.3000373
Correction
Correction: Attention promotes the neural encoding of prediction errors
PLOS Biology: published July 10, 2019 | https://doi.org/10.1371/journal.pbio.3000368