Native drivers of fish life history traits are lost during the invasion process

Rapid adaptation to global change can counter vulnerability of species to population declines and extinction. Theoretically, under such circumstances both genetic variation and phenotypic plasticity can maintain population fitness, but empirical support for this is currently limited. Here, we aim to characterize the role of environmental and genetic diversity, and their prior evolutionary history (via haplogroup profiles) in shaping patterns of life history traits during biological invasion. Data were derived from both genetic and life history traits including a morphological analysis of 29 native and invasive populations of topmouth gudgeon Pseudorasbora parva coupled with climatic variables from each location. General additive models were constructed to explain distribution of somatic growth rate (SGR) data across native and invasive ranges, with model selection performed using Akaike's information criteria. Genetic and environmental drivers that structured the life history of populations in their native range were less influential in their invasive populations. For some vertebrates at least, fitness‐related trait shifts do not seem to be dependent on the level of genetic diversity or haplogroup makeup of the initial introduced propagule, nor of the availability of local environmental conditions being similar to those experienced in their native range. As long as local conditions are not beyond the species physiological threshold, its local establishment and invasive potential are likely to be determined by local drivers, such as density‐dependent effects linked to resource availability or to local biotic resistance.     

Elicitation Improves the Leaf Area,Enzymatic Activities,Antioxidant Activity and Content of Secondary Metabolites in Achillea millefolium L. Grown in the Field

Salicylic acid (SA) is a plant hormone that stimulates the growth and metabolism of plants, also acting as an abiotic elicitor. This study aimed to evaluate the effect of SA on leaf production, leaf area and synthesis of secondary compounds in yarrow plants. The experiments were conducted under field conditions in two consecutive years and f-received SA foliar applications (T1-control; T2-1.0 mmol L⁻¹ applications at 20, 60 and 100 days after planting (DAP) and T3-1.0 mmol L⁻¹ applications at 100 DAP during 3 days). The exogenous application of SA resulted in increases in leaf area (total and specific), number of leaves and leaf mass ratio of yarrow plants, polyphenolic compounds, phenylalanine ammonia-lyase and chalcone synthase enzymes and the antioxidant activity of the plant extract. The HPLC–DAD–MS/MS analysis of phenolic compounds revealed increases in the amounts of quinic acid and rutin. The results of this research lead us to affirm that SA exerted both the hormonal effect on number of leaves and leaf area, and also acted as eliciting substance.

     

Factors associated with Diaphorina citri immigration into commercial citrus orchards in São Paulo State,Brazil

Seasonality often influences multiple aspects of vector-borne plant diseases. With respect to the management of plant disease vectors, an understanding of the factors driving seasonal changes in vector flight activity may improve management outcomes by facilitating more proactive application of control measures. One of the most challenging issues for citrus Huanglongbing management is to forecast when disease primary spread by bacteriliferous Diaphorina citri will occur. We monitored the temporal patterns of immigrating psyllids, using upwards of 1,200 traps spread among 9 citrus farms and checked on a weekly basis over 4 years. This dataset was analysed with a set of hierarchical models to estimate the effect of climatic variables on citrus foliage production (i.e. flush), and effects of climatic variables and citrus foliage dynamics on D. citri catches over the season. The results showed substantial seasonal variability in immigrating D. citri abundance, with the critical dispersal/migration period occurring between end of winter and spring. During this period, 65% of the total psyllids were collected on sticky traps. Seasonality of immigrating D. citri coincided with changes in certain climate variables, with negative effects of humidity and daily maximum temperatures, and a positive effect of rainfall amount in prior weeks. Maximum temperature and both daily minimum temperature and rainfall during prior weeks were also associated with new citrus flush production, which itself was positively related to immigrating D. citri abundance. Based on these results, citrus growers should be aware and intensify the frequency of psyllid control tactics (i.e. insecticide and/or kaolin sprays) during this period in order to prevent Ca. L. asiaticus transmission. These results are an important step towards developing the predictive framework needed to refine D. citri and huanglongbing management.     

Differentiation of the binding of two ligands to a tetrameric protein with a single symmetric active site by 19F NMR

R67 dihydrofolate reductase (R67 DHFR) is a plasmid‐encoded enzyme that confers resistance to the antibacterial drug trimethoprim. R67 DHFR is a tetramer with a single active site that is unusual as both cofactor and substrate are recognized by symmetry‐related residues. Such promiscuity has limited our previous efforts to differentiate ligand binding by NMR. To address this problem, we incorporated fluorine at positions 4, 5, 6, or 7 of the indole rings of tryptophans 38 and 45 and characterized the spectra to determine which probe was optimal for studying ligand binding. Two resonances were observed for all apo proteins. Unexpectedly, the W45 resonance appeared broad, and truncation of the disordered N‐termini resulted in the appearance of one sharp W45 resonance. These results are consistent with interaction of the N‐terminus with W45. Binding of the cofactor broadened W38 for all fluorine probes, whereas substrate, dihydrofolate, binding resulted in the appearance of three new resonances for 4‐ and 5‐fluoroindole labeled protein and severe line broadening for 6‐ and 7‐fluoroindole R67 DHFR. W45 became slightly broader upon ligand binding. With only two peaks in the ¹⁹F NMR spectra, our data were able to differentiate cofactor and substrate binding to the single, symmetric active site of R67 DHFR and yield binding affinities.     

Correction to: Whole-Genome sequencing and comparative genomics of Mycobacterium spp. from farmed Atlantic and coho salmon in Chile

Antonie van Leeuwenhoek -     

Survivorship and Spatial Patterns of an Urban Population of Texas Horned Lizards

Habitat fragmentation has negative consequences on threatened and endangered species by creating isolated populations. The Texas horned lizard (Phrynosoma cornutum) is experiencing population declines and localized extirpations throughout its range and has been classified as a species of greatest conservation need in Oklahoma, USA. Younger age classes have been poorly studied but may be vital to the stability of remaining populations. To address gaps in knowledge concerning subadult (hatchling and juvenile) morphometrics, survivorship, and home range sizes, we studied 2 cohorts of subadults, for 2 years each, covering their hatching and juvenile years (2016–2019). We used a combination of radio-telemetry and novel harmonic radar methodology to study a closed population of Texas horned lizards in 15 ha of native grassland at Tinker Air Force Base, Oklahoma. Population abundance for adults and juveniles was estimated as 56.5 ± 5.5 lizards and density as 7.96 lizards/ha. Our lowest estimates of survival indicated an average survival probability for the hatchling life stage of 0.285 (95% CI = 0.15–0.44), which is lower than for adults on the site. Average home range size increased from hatchling to adult life stages. Our results will have an immediate effect on the planning and assessment of ongoing headstart and management programs for Texas horned lizards. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

An Evaluation of the Role the Internet Site Petfinder Plays in Cat Adoptions

To better understand factors contributing to cat adoptions, this study was used to explore a possible association between an adoptable cat's popularity on Petfinder and the cat's length of availability for adoption at a managed-intake nonhuman animal shelter. This study was also used to examine factors associated with a cat's popularity on Petfinder and the percentage of adopters who visited Petfinder before making adoption decisions. One third of adopters surveyed visited Petfinder before adopting, and half of those had viewed their adopted cats' Petfinder profiles. The number of clicks per day that cats received on the site was negatively correlated with their length of availability. Age at adoption was positively correlated with length of availability and negatively correlated with number of clicks per day. Coat color was a strong predictor of number of clicks per day and length of availability. The only variable within the photographer's control significantly associated with number of clicks per day was whether the photos included toys. Although cats' physical characteristics are strong predictors of their popularity, strategic use of toys in cats' photographs may promote adoptions of cats who are typically overlooked.     

New Insights into the in situ Microscopic Visualization and Quantification of Inorganic Polyphosphate Stores by 4’,6-Diamidino-2-Phenylindole (DAPI)-Staining

Inorganic polyphosphate (PolyP) is a biological polymer that plays important roles in the cell physiology of both prokaryotic and eukaryotic organisms. Among the available methods for PolyP localization and quantification, a 4’,6-diamidino-2-phenylindole(DAPI)-based assay has been used for visualization of PolyP-rich organelles. Due to differences in DAPI permeability to different compartments and/or PolyP retention after fixation, a general protocol for DAPI-PolyP staining has not yet been established. Here, we tested different protocols for DAPI-PolyP detection in a range of samples with different levels of DAPI permeability, including subcellular fractions, free-living cells and cryosections of fixed tissues. Subcellular fractions of PolyP-rich organelles yielded DAPI-PolyP fluorescence, although those with a complex external layer usually required longer incubation times, previous aldehyde fixation and/or detergent permeabilization. DAPI-PolyP was also detected in cryosections of OCT-embedded tissues analyzed by multiphoton microscopy. In addition, a semi-quantitative fluorimetric analysis of DAPI-stained fractions showed PolyP mobilization in a similar fashion to what has been demonstrated with the use of enzyme-based quantitative protocols. Taken together, our results support the use of DAPI for both PolyP visualization and quantification, although specific steps are suggested as a general guideline for DAPI-PolyP staining in biological samples with different degrees of DAPI and PolyP permeability.Key words: DAPI, polyphosphate, fluorescence, fluorimetry     

A study of the anti‐plasmodium activity of angiotensin II analogs

Controlling the dissemination of malaria requires the development of new drugs against its etiological agent, a protozoan of the Plasmodium genus. Angiotensin II and its analog peptides exhibit activity against the development of immature and mature sporozoites of Plasmodium gallinaceum. In this study, we report the synthesis and characterization of angiotensin II linear and cyclic analogs with anti‐plasmodium activity. The peptides were synthesized by a conventional solid‐phase method on Merrifield's resin using the t‐Boc strategy, purified by RP‐HPLC and characterized by liquid chromatography/ESI (+) MS (LC‐ESI(+)/MS), amino acid analysis, and capillary electrophoresis. Anti‐plasmodium activity was measured in vitro by fluorescence microscopy using propidium iodine uptake as an indicator of cellular damage. The activities of the linear and cyclic peptides are not significantly different (p < 0.05). Kinetics studies indicate that the effects of these peptides on plasmodium viability overtime exhibit a sigmoidal profile and that the system stabilizes after a period of 1 h for all peptides examined. The results were rationalized by partial least‐square analysis, assessing the position‐wise contribution of each amino acid. The highest contribution of polar amino acids and a Lys residue proximal to the C‐terminus, as well as that of hydrophobic amino acids in the N‐terminus, suggests that the mechanism underlying the anti‐malarial activity of these peptides is attributed to its amphiphilic character. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.