Tryptophan-metabolizing gut microbes regulate adult neurogenesis via the aryl hydrocarbon receptor.

While modulatory effects of gut microbes on neurological phenotypes have been reported, the mechanisms remain largely unknown. Here, we demonstrate that indole, a tryptophan metabolite produced by tryptophanase-expressing gut microbes, elicits neurogenic effects in the adult mouse hippocampus. Neurogenesis is reduced in germ-free (GF) mice and in GF mice monocolonized with a single-gene knockout (KO) mutant unable to produce indole.

Digest: Does size matter? Condition-dependent sexual selection in Drosophila melanogaster.

What conditions favor competitive outcomes at different stages of the reproductive process? De Nardo et al. found that in Drosophila melanogaster, the evolution of male secondary sexual traits was influenced by sexual selection through mating success and competitive fertilization.

Harnessing NKT cells for vaccination.

Natural killer T (NKT) cells are innate-like T cells capable of enhancing both innate and adaptive immune responses. When NKT cells are stimulated in close temporal association with co-administered antigens, strong antigen-specific immune responses can be induced, prompting the study of NKT cell agonists as novel immune adjuvants. This activity has been attributed to the capacity of activated NKT cells to act as universal helper cells, with the ability to provide molecular signals to dendritic cells and B cells that facilitate T cell and antibody responses, respectively.

Response to Comment on Trophic strategy and bleaching resistance in reef-building corals.

Recently, we published a novel method used to assess the trophic niches of different coral species and demonstrated that their nutrition varied considerably, with some species highly dependent on their photosynthetic algal symbionts and others able to feed on plankton to meet energetic requirements. Adjustments to the use of this tool are necessary when it is applied to other scientific questions and symbiotic organisms. We respond to a comment highlighting a risk of bias in the methods, discuss suggested adjustments, and propose further refinements to improve method robustness.

Successional Development of Fungal Communities Associated with Decomposing Deadwood in a Natural Mixed Temperate Forest.

Deadwood represents an important carbon stock and contributes to climate change mitigation. Wood decomposition is mainly driven by fungal communities. Their composition is known to change during decomposition, but it is unclear how environmental factors such as wood chemistry affect these successional patterns through their effects on dominant fungal taxa.

Antibacterial Activity of Nanoparticles.

Antimicrobial resistance (AMR) is predicted to soon become one of the most serious threats to human and animal health [...

So Much for Glucosinolates: A Generalist Does Survive and Develop on Brassicas, but at What Cost?

While plants produce complex cocktails of chemical defences with different targets and efficacies, the biochemical effects of phytotoxin ingestion are often poorly understood. Here, we examine the physiological and metabolic effects of the ingestion of glucosinolates (GSLs), the frontline chemical defenses of brassicas (crucifers), on the generalist herbivore . We focus on kale and cabbage, two crops with similar foliar GSL concentrations but strikingly different GSL compositions.

Intranasal galantamine/chitosan complex nanoparticles elicit neuroprotection potentials in rat brains via antioxidant effect.

Background: Alzheimer's disease is a common cause of dementia in the elderly. Galantamine hydrobromide (GH) is an anti-Alzheimer cholinesterase inhibitor that has an intrinsic antioxidant effect. In a previous study, GH was complexed with chitosan to prepare intranasal GH/chitosan complex nanoparticles (CX-NP2).

Digest: On the contribution of phenotypic plasticity to adaptation in desert environments.

How do organisms adapt to new environments, and what role does phenotypic plasticity play? Bittner et al. compared water consumption in laboratory-reared house mice derived from xeric and mesic populations and found evidence for adaptive phenotypic plasticity as well as genetic differences between populations.

Population Structure Limits Parallel Evolution in Sticklebacks.

Population genetic theory predicts that small effective population sizes (Ne) and restricted gene flow limit the potential for local adaptation. In particular, the probability of evolving similar phenotypes based on shared genetic mechanisms (i.e.

Active Microbiome Structure and Functional Analyses of Freshwater Benthic Biofilm Samples Influenced by RNA Extraction Methods.

Advances in high-throughput sequencing technologies have enabled extensive studies of freshwater biofilms and significant breakthroughs in biofilm meta-omics. To date, however, no standardized protocols have been developed for the effective isolation of RNA from freshwater benthic biofilms. In this study, we compared column-based kit RNA extraction with five RNAzol-based extractions, differentiated by various protocol modifications.

Clinical and Pathologic Presentation of Primary Ocular Surface Tumors among Zambians.

Aim: This study aimed to characterize the clinical and pathologic presentation of ocular surface tumors (OSTs) and to more precisely differentiate the grades of ocular surface squamous neoplasia (OSSN) and benign lesions among Zambians.

Methods: Two-hundred sixty-five Zambian patients presenting with ocular surface growths, suspicious for OSSN, were recruited between November 2017 and November 2019 to a cross-sectional study to investigate their lesions. Sociodemographic data were collected, HIV infection status and vision tests were performed, and lesions were measured and documented.

A small effect of conservation agriculture on soil biodiversity that differs between biological kingdoms and geographic locations.

Larger easily visible animals and plants are negatively affected by agrochemicals used for intensive food production, but we do not understand the general spatial and temporal effects of agrochemicals on the multitudes of bacteria, fungi, and small invertebrate animals that underpin ecosystem productivity. We sequenced the 16S, ITS2, and COI DNA barcode regions from 648 New Zealand vineyard soil samples managed under either conventional or low-agrochemical-input conservation approaches across two regions and three seasons in 1 year and discovered at least 170,000 phylotypes (taxa) with >97% genetic identity. Management approach correlated with a significant 2%-10% difference in the abundances of phylotypes that differed over regions and seasons.

Seed Dormancy and Preharvest Sprouting in Quinoa ( Willd.).

Quinoa ( Willd.) is a culturally significant staple food source that has been grown for thousands of years in South America. Due to its natural drought and salinity tolerance, quinoa has emerged as an agronomically important crop for production in marginal soils, in highly variable climates, and as part of diverse crop rotations.

Development of antibiotic resistance in the ocular Pseudomonas aeruginosa clone ST308 over twenty years.

Corneal infection caused by a bacteria Pseudomonas aeruginosa is common cause of ocular morbidity. Increasing antibiotic resistance by ocular P. aeruginosa is an emerging concern.

The Potential of Single-Cell Oils Derived From Filamentous Fungi as Alternative Feedstock Sources for Biodiesel Production.

Microbial lipids, also known as single-cell oils (SCOs), are highly attractive feedstocks for biodiesel production due to their fast production rates, minimal labor requirements, independence from seasonal and climatic changes, and ease of scale-up for industrial processing. Among the SCO producers, the less explored filamentous fungi (molds) exhibit desirable features such as a repertoire of hydrolyzing enzymes and a unique pellet morphology that facilitates downstream harvesting. Although several oleaginous filamentous fungi have been identified and explored for SCO production, high production costs and technical difficulties still make the process less attractive compared to conventional lipid sources for biodiesel production.

Whole-genome sequencing from the New Zealand Saccharomyces cerevisiae population reveals the genomic impacts of novel microbial range expansion.

Saccharomyces cerevisiae is extensively utilized for commercial fermentation, and is also an important biological model; however, its ecology has only recently begun to be understood. Through the use of whole-genome sequencing, the species has been characterized into a number of distinct subpopulations, defined by geographical ranges and industrial uses. Here, the whole-genome sequences of 104 New Zealand (NZ) S.

Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action.

Biofilms have several characteristics that ensure their survival in a range of adverse environmental conditions, including high cell numbers, close cell proximity to allow easy genetic exchange (e.g., for resistance genes), cell communication and protection through the production of an exopolysaccharide matrix.

Influence of interspecies interactions on the spatial organization of dual species bacterial communities.

Interspecies interactions in bacterial biofilms have important impacts on the composition and function of communities in natural and engineered systems. To investigate these interactions, synthetic communities provide experimentally tractable systems. Biofilms grown on agar-surfaces have been used for investigating the eco-evolutionary and biophysical forces that determine community composition and spatial distribution of bacteria.

Separate and combined Hanseniaspora uvarum and Metschnikowia pulcherrima metabolic volatiles are attractive to Drosophila suzukii in the laboratory and field.

Drosophila suzukii flies cause economic losses to fruit crops globally. Previous work shows various Drosophila species are attracted to volatile metabolites produced by individual fruit associated yeast isolates, but fruits naturally harbour a rich diversity of yeast species. Here, we report the relative attractiveness of D.

Rapamycin and abundant TCR stimulation are required for the generation of stable human induced regulatory T cells.

Objectives: Regulatory T cells (Tregs) are a vital sub-population of CD4 T cells with major roles in immune tolerance and homeostasis. Given such properties, the use of regulatory T cells for immunotherapies has been extensively investigated, with a focus on adoptive transfer of expanded natural Tregs (nTregs). For immunotherapies, induced Tregs (iTregs), generated from naïve CD4 T cells, provide an attractive alternative, given the ease of generating cell numbers required for clinical dosage.

Digest: Sexually selected weapons: Winning the fight, but losing the war for reproduction on a changing battlefield.

What conditions favor the evolution of large animal weapons? In the Japanese rhinoceros beetle, Trypoxylus dichotomus, del Sol et al. found that selection favors large horns in populations where males compete over guardianship of scarce female feeding territories. However, in other populations, an abundance of female feeding territories reduces the chance of mating success for these guarding males, leading to the evolution of relatively shorter horn sizes.

Impacts of Wet Market Modernization Levels and Hygiene Practices on the Microbiome and Microbial Safety of Wooden Cutting Boards in Hong Kong.

Accessing food through wet markets is a common global daily occurrence, where fresh meat can be purchased to support an urbanizing world population. Similar to the wet markets in many other metropolitan cities in Asia, Hong Kong wet markets vary and are characterized by differing hygiene routines and access to essential modern technologies. The lack of risk assessments of food contact surfaces in these markets has led to substantial gaps in food safety knowledge and information that could help improve and maintain public health.

Tree seedling trait optimization and growth in response to local-scale soil and light variability.

At local scales, it has been suggested that high levels of resources lead to increased tree growth via trait optimization (highly peaked trait distribution). However, this contrasts with (1) theories that suggest that trait optimization and high growth occur in the most common resource level and (2) empirical evidence showing that high trait optimization can be also found at low resource levels. This raises the question of how are traits and growth optimized in highly diverse plant communities.