Water relations determine short time leaf growth patterns in the mangrove Avicennia marina (Forssk.) Vierh.

High‐resolution leaf growth is rarely studied despite its importance as a metric for plant performance and resource use efficiency. This is in part due to methodological challenges. Here, we present a method for in situ leaf growth measurements in a natural environment. We measured instantaneous leaf growth on a mature Avicennia marina subsp. australasica tree over several weeks. We measured leaf expansion by taking time‐lapse images and analysing them using marker tracking software. A custom‐made instrument was designed to enable long‐term field studies. We detected a distinct diel growth pattern with leaf area shrinkage in the morning and leaf expansion in the afternoon and at night. On average, the observed daily shrinkage was 37% of the net growth. Most of the net growth occurred at night. Diel leaf area shrinkage and recovery continued after growth cessation. The amount of daily growth was negatively correlated with shrinkage, and instantaneous leaf growth and shrinkage were correlated with changes in leaf turgor. We conclude that, at least in this tree species, instantaneous leaf growth patterns are very strongly linked to, and most likely driven by, leaf water relations, suggesting decoupling of short‐term growth patterns from carbon assimilation.     

Do alternative reproductive strategies in the Wellington tree weta represent different behavioural types?

In many animal species, variation in reproductive success among individuals has led to the evolution of alternative mating strategies, which in the case of insects can often be correlated with developmental trajectories. In the Wellington tree weta, Hemideina crassidens, males can mature at the 8th, 9th or 10th instar, while females mature at the 10th instar only. A number of morphological attributes including male head and mandible size correlate with final instar number, and as these attributes represent a form of weaponry, they are often used in mate/site guarding and male–male competition. Tenth instar males have larger head/mandible/body sizes and show a conventional (guarder) reproductive strategy, whereas smaller 8th instar males typically show an unconventional (sneaker) strategy. In contrast, 9th instar males are predicted to adopt a “jack‐of‐all‐trades” strategy whereby they can fight or sneak depending context. Here, we tested whether alternative reproductive morphs exhibit strategy‐specific differences in risk‐taking associated with refuge emergence, activity and antipredator behaviour and further, whether these traits correlate to form a behavioural syndrome. We found that tree weta show consistent and repeatable differences in activity and refuge use at the individual level; however, behavioural covariances suggest that only 8th instar males exhibit a behavioural syndrome. That 9th instar males show high plasticity and variance in their gallery‐related behaviours supports the hypothesis that these males are a “jack‐of‐all‐trades.” Contrary to our predictions, antipredator behaviour was not correlated with other traits, and differences in behaviour overall were consistently more pronounced between individuals rather than between male morphs or sexes.     

Evolutionary history of the SARS-CoV-2 Gamma variant of concern (P.1): a perfect storm

Our goal was to describe in more detail the evolutionary history of Gamma and two derived lineages (P.1.1 and P.1.2), which are part of the arms race that SARS-CoV-2 wages with its host. A total of 4,977 sequences of the Gamma strain of SARS-CoV-2 from Brazil were analyzed. We detected 194 sites under positive selection in 12 genes/ORFs: Spike, N, M, E, ORF1a, ORF1b, ORF3, ORF6, ORF7a, ORF7b, ORF8, and ORF10. Some diagnostic sites for Gamma lacked a signature of positive selection in our study, but these were not fixed, apparently escaping the action of purifying selection. Our network analyses revealed branches leading to expanding haplotypes with sites under selection only detected when P.1.1 and P.1.2 were considered. The P.1.2 exclusive haplotype H_5 originated from a non-synonymous mutational step (H3509Y) in H_1 of ORF1a. The selected allele, 3509Y, represents an adaptive novelty involving ORF1a of P.1. Finally, we discuss how phenomena such as epistasis and antagonistic pleiotropy could limit the emergence of new alleles (and combinations thereof) in SARS-COV-2 lineages, maintaining infectivity in humans, while providing rapid response capabilities to face the arms race triggered by host immuneresponses.     

The actin nucleator Spir-1 is a virus restriction factor that promotes innate immune signalling

Cellular proteins often have multiple and diverse functions. This is illustrated with protein Spir-1 that is an actin nucleator, but, as shown here, also functions to enhance innate immune signalling downstream of RNA sensing by RIG-I/MDA-5. In human and mouse cells lacking Spir-1, IRF3 and NF-κB-dependent gene activation is impaired, whereas Spir-1 overexpression enhanced IRF3 activation. Furthermore, the infectious virus titres and sizes of plaques formed by two viruses that are sensed by RIG-I, vaccinia virus (VACV) and Zika virus, are increased in Spir-1 KO cells. These observations demonstrate the biological importance of Spir-1 in the response to virus infection. Like cellular proteins, viral proteins also have multiple and diverse functions. Here, we also show that VACV virulence factor K7 binds directly to Spir-1 and that a diphenylalanine motif of Spir-1 is needed for this interaction and for Spir-1-mediated enhancement of IRF3 activation. Thus, Spir-1 is a new virus restriction factor and is targeted directly by an immunomodulatory viral protein that enhances virus virulence and diminishes the host antiviral responses.     

Functional insight into LOAD-associated microglial response genes

Alzheimer''s disease (AD) is characterized by the presence of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs), neuronal and synaptic loss and inflammation of the central nervous system (CNS). The majority of AD research has been dedicated to the understanding of two major AD hallmarks (i.e. Aβ and NFTs); however, recent genome-wide association studies (GWAS) data indicate neuroinflammation as having a critical role in late-onset AD (LOAD) development, thus unveiling a novel avenue for AD therapeutics. Recent evidence has provided much support to the innate immune system''s involvement with AD progression; however, much remains to be uncovered regarding the role of glial cells, specifically microglia, in AD. Moreover, numerous variants in immune and/or microglia-related genes have been identified in whole-genome sequencing and GWAS analyses, including such genes as TREM2, CD33, APOE, API1, MS4A, ABCA7, BIN1, CLU, CR1, INPP5D, PICALM and PLCG2. In this review, we aim to provide an insight into the function of the major LOAD-associated microglia response genes.     

Screening the pandemic response box identified benzimidazole carbamates,Olorofim and ravuconazole as promising drug candidates for the treatment of eumycetoma

Eumycetoma is a chronic subcutaneous neglected tropical disease that can be caused by more than 40 different fungal causative agents. The most common causative agents produce black grains and belong to the fungal orders Sordariales and Pleosporales. The current antifungal agents used to treat eumycetoma are itraconazole or terbinafine, however, their cure rates are low. To find novel drugs for eumycetoma, we screened 400 diverse drug-like molecules from the Pandemic Response Box against common eumycetoma causative agents as part of the Open Source Mycetoma initiative (MycetOS). 26 compounds were able to inhibit the growth of Madurella mycetomatis, Madurella pseudomycetomatis and Madurella tropicana, 26 compounds inhibited Falciformispora senegalensis and seven inhibited growth of Medicopsis romeroi in vitro. Four compounds were able to inhibit the growth of all five species of fungi tested. They are the benzimidazole carbamates fenbendazole and carbendazim, the 8-aminoquinolone derivative tafenoquine and MMV1578570. Minimal inhibitory concentrations were then determined for the compounds active against M. mycetomatis. Compounds showing potent activity in vitro were further tested in vivo. Fenbendazole, MMV1782387, ravuconazole and olorofim were able to significantly prolong Galleria mellonella larvae survival and are promising candidates to explore in mycetoma treatment and to also serve as scaffolds for medicinal chemistry optimisation in the search for novel antifungals to treat eumycetoma.     

The Distribution of Perkinsus marinus in Gulf Coast Oysters: Its Relationship with Temperature,Reproduction, and Pollutant Body Burden

Oysters from 48 Gulf of Mexico sites were examined for presence and infection intensity of the endoparasite, Perkinsus (= Dermocystidium) marinus (Mackin, Owen and Collier, 1950) as part of NOAA's Status and Trends Mussel Watch Program. Prevalence exceeded 75% at 25 sites. Infection intensity did not vary with sex or reproductive stage. Latitude, total polynuclear aromatic hydrocarbon (PAH) content and industrial and agricultural land use significantly affected the parasite's distribution. PAH and pesticide concentrations were latitudinally dependent, suggesting an impact of spawning frequency on uptake and depuration. P. marinus analysis complements the use of pollutant body burden for determining change in environmental quality because it responds differently than pollutant body burden to the biology and ecology of the oyster.