Is Mate Provisioning Predicted by Ornamentation? A Test with Northern Cardinals (Cardinalis cardinalis)

Male birds of many species feed their mates during courtship and incubation. The amount of food provided can be substantial and even essential for successful reproduction in some species, and can influence female nest attentiveness in many others. Additionally, mate provisioning may predict later nestling feeding rates. Females may thus benefit from being able to determine male provisioning effort. We assessed the expression of several ornaments, known to indicate condition in male northern cardinals (Cardinalis cardinalis), and compared these with mate provisioning rates, nestling feeding rates, and nest attentiveness. We found that male ornamentation may not be indicative of mate provisioning rates. Mate provisioning rate did not co‐vary with reproductive success, male feedings to nestlings, or nest attentiveness of females. However, females which were fed more often during incubation tended to provision nestlings less. Reduced female parental effort following extensive incubation feeding may be indicative of females using incubation feeding to assess future male parental effort. Male hormonal condition that favors high rates of nestling provisioning may be a proximate cause of mate provisioning during incubation, even in the absence of selection, favoring high rates of mate provisioning. Both sexes may have capitalized on this unselected behavior.     

Archaeal overdominance close to life-limiting conditions in geothermally influenced hypersaline lakes at the Danakil Depression,Ethiopia

The Dallol protovolcanic area on the Danakil Depression (Afar region, Ethiopia) exhibits unique hydrothermal manifestations in hypersaline context, yielding varied polyextreme physicochemical conditions. Previous studies identified a wide archaeal diversity in less extreme brines but failed to identify microorganisms thriving in either high-chaotropicity, low-water-activity brines or hyperacidic-hypersaline Na-Fe-rich brines. Recently, we accessed several small lakes under intense degassing activity adjacent to the Round Mountain, west to the Dallol dome [Western Canyon Lakes (WCL); WCL1-5]. They exhibited intermediate parameter combinations (pH ~ 5, 34%–41% (weight/volume) NaCl-dominated salts with relatively high levels of chaotropic Mg-Ca salts) that should allow to better constrain life limits. These lakes were overwhelmingly dominated by Archaea, encompassing up to 99% of prokaryotic 16S rRNA gene amplicon sequences in metabarcoding studies. The majority belonged to Halobacteriota and Nanohaloarchaeota, the latter representing up to half of prokaryotic sequences. Optical and epifluorescence microscopy showed active cells in natural samples and diverse morphotypes in enrichment cultures. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy revealed tiny cells (200–300 nm diameter) epibiotically associated with somewhat larger cells (0.6–1 μm) but also the presence of silica-dominated precipitates of similar size and shape, highlighting the difficulty of distinguishing microbes from mineral biomorphs in this kind of low-biomass systems.     

Innate Immunity and the Inter-exposure Interval Determine the Dynamics of Secondary Influenza Virus Infection and Explain Observed Viral Hierarchies

Influenza is an infectious disease that primarily attacks the respiratory system. Innate immunity provides both a very early defense to influenza virus invasion and an effective control of viral growth. Previous modelling studies of virus–innate immune response interactions have focused on infection with a single virus and, while improving our understanding of viral and immune dynamics, have been unable to effectively evaluate the relative feasibility of different hypothesised mechanisms of antiviral immunity. In recent experiments, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated that viruses differed in their ability to induce a state of temporary immunity or viral interference capable of modifying the infection kinetics of the subsequent exposure. These results imply that virus-induced early immune responses may be responsible for the observed viral hierarchy. Here we introduce and analyse a family of within-host models of re-infection viral kinetics which allow for different viruses to stimulate the innate immune response to different degrees. The proposed models differ in their hypothesised mechanisms of action of the non-specific innate immune response. We compare these alternative models in terms of their abilities to reproduce the re-exposure data. Our results show that 1) a model with viral control mediated solely by a virus-resistant state, as commonly considered in the literature, is not able to reproduce the observed viral hierarchy; 2) the synchronised and desynchronised behaviour of consecutive virus infections is highly dependent upon the interval between primary virus and challenge virus exposures and is consistent with virus-dependent stimulation of the innate immune response. Our study provides the first mechanistic explanation for the recently observed influenza viral hierarchies and demonstrates the importance of understanding the host response to multi-strain viral infections. Re-exposure experiments provide a new paradigm in which to study the immune response to influenza and its role in viral control.     

Molecular Illustration in Research and Education: Past,Present, and Future

Two-dimensional illustration is used extensively to study and disseminate the results of structural molecular biology. Molecular graphics methods have been and continue to be developed to address the growing needs of the structural biology community, and there are currently many effective, turn-key methods for displaying and exploring molecular structure. Building on decades of experience in design, best-practice resources are available to guide creation of illustrations that are effective for research and education communities.     

Diverse reproductive barriers in hybridising crickets suggests extensive variation in the evolution and maintenance of isolation

Reproductive barriers reduce gene flow between populations and maintain species identities. A diversity of barriers exist, acting before, during and after mating. To understand speciation and coexistence, these barriers need to be quantified and their potential interactions revealed. We use the hybridising field crickets Gryllus bimaculatus and G. campestris as a model to understand the full compliment and relative strength of reproductive barriers. We find that males of both species prefer conspecific females, but the effect is probably too weak to represent a barrier. In contrast, prezygotic barriers caused by females being more attracted to conspecific male song and preferentially mounting and mating with conspecifics are strong and asymmetric. Postzygotic barriers vary in direction; reductions in fecundity and egg viability create selection against hybridisation, but hybrids live longer than pure-bred individuals. Hybrid females show a strong preference for G. bimaculatus songs, which together with a complete lack of hybridisation by G. campestris females, suggests that asymmetric gene flow is likely. For comparison, we review reproductive barriers that have been identified between other Gryllids and conclude that multiple barriers are common. Different species pairs are separated by qualitatively different combinations of barriers, suggesting that reproductive isolation and even the process of speciation itself may vary widely even within closely related groups.     

Dopamine Transporter Genotype as a Risk Factor for Obesity in African-American Smokers

Objective: To assess the association between a polymorphism related to dopamine function, dopamine transport (SLC6A3), and obesity in smokers. Research Methods and Procedures: Logistic regression was used to assess the relationship between this genetic polymorphism and obesity (body mass index ≥ 30 kg/m²) from a sample of 510 smokers who smoked at least 10 cigarettes per day and who were participating in a study designed to examine genetic and nongenetic predictors of response to a pharmacological treatment. Results: The likelihood of obesity in African Americans (N = 90) with the 10/10 SLC6A3 genotype was 5.16 times that of African Americans with 9/9 or 9/10 SLC6A3 genotypes (odds ratio = 5.16, confidence interval = 1.60 to 16.65). There was no association of the SLC6A3 genotype with obesity for non-Hispanic whites (N = 420). Discussion: These results suggest that variants of the dopamine transporter gene may be related to obesity in African-American smokers. Possible mechanisms responsible for the association between dopamine transport and obesity in African-American smokers are discussed.     

Histochemistry and composition of the cell walls of styles of Nicotiana alata Link et Otto

The cell walls of styles of Nicotiana alata Link et Otto (ornamental tobacco; Solanaceae) were analysed chemically and examined histochemically. Cell-wall preparations were obtained from whole styles and from isolated transmitting-tissue cells. The style epidermal cells were shown histochemically to have thick, lignified secondary walls. These walls probably constituted a large proportion of the cell-wall preparation from whole styles as analysis of whole-style walls indicated that the major polysaccharides were xylans and cellulose, which are typical of lignified secondary walls of Magnoliopsida (dicotyledons). Lignification of the style epidermal walls was also demonstrated histochemically in 10 other species (5 genera including Nicotiana) of the sub-family Cestroideae of the Solanaceae, but not in 15 species (9 genera) of the sub-family Solanoideae of the Solanaceae, nor in 3 other species of dicotyledons and 2 species of Liliopsida (monocotyledons). Analysis of the cell-wall preparation from isolated transmitting-tissue cells of N. alata indicated that these contained cellulose, xyloglucans, and pectic polysaccharides, which is typical of primary cell walls of dicotyledons. However, the analysis indicated that the walls also contained an unusually high proportion of Type II arabinogalactans. Staining of the transmitting-tissue cell-wall preparation with β-glucosyl Yariv reagent, a histochemical reagent specific for arabinogalactan proteins, confirmed their presence, which may be related to the role of these cells in secreting the stylar extracellular matrix.     

Intranasal vaccination with a lentiviral vector protects against SARS-CoV-2 in preclinical animal models

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Gene flow and natal dispersal in the Siberian flying squirrel based on direct and indirect data

Dispersal is a key determinant of the evolution and ecology of species. For a comprehensive picture of dispersal, a combination of both field observations and indirect genetic measures are required, as both of these have strengths that may mitigate the other’s limitations. Here, we used microsatellite markers and radio-telemetry data to study dispersal and gene flow in Siberian flying squirrels. Genetic data confirmed our empirical results that dispersal is female biased in the flying squirrel. Female bias in dispersal is exceptional among mammals and in flying squirrels is probably explained by competition for food resources and nesting cavities among mothers and daughters. The individual-level genetic pattern was influenced by isolation by distance. Using this information fairly comparable dispersal distances were derived using indirect data as observed directly with radio telemetry. Thus, our results support the recent conclusion that individual-level genetic data can be useful in inferring dispersal distances for species for which direct data are lacking.