Social insect males may operate at their physiological limits, which might explain why they depend on support from their sister helpers and never contribute towards the colony. In social insects, ...queens require large numbers of sperm to build and maintain their colonies. We tested the idea that selection for extreme levels of fecundity resulted in males reducing investments into other life history traits. We show that exposure of males to elevated temperatures and immune challenges had an immediate effect of reducing male fecundity.
Obesity rates in the U.S. continue to increase, with nearly 50% of the population being either obese or morbidly obese. Obesity, along with female sex, are leading risk factors for sporadic ...Alzheimer's Disease (AD) necessitating the need to better understand how these variables impact cellular function independent of age or genetic mutations. Animal and clinical studies both indicate that autophagy-lysosomal pathway (ALP) dysfunction is among the earliest known cellular systems to become perturbed in AD, preceding cognitive decline, yet little is known about how obesity and sex affects these cellular functions in the hippocampus, a brain region uniquely susceptible to the negative effects of obesity. We hypothesized that obesity would negatively affect key markers of ALP in the hippocampus, effects would vary based on sex, and that caloric restriction would counteract obesity effects.
Female and male mice were placed on an obesogenic diet for 10 months, at which point half were switched to caloric restriction for three months, followed by cognitive testing in the Morris watermaze. Hippocampus was analyzed by western blot and qPCR.
Cognitive function in female mice responded differently to caloric restriction based on whether they were on a normal or obesogenic diet; male cognition was only mildly affected by caloric restriction and not obesity. Significant male-specific changes occurred in cellular markers of autophagy, including obesity increasing pAkt, Slc38a9, and Atg12, while caloric restriction reduced pRPS6 and increased Atg7. In contrast females experienced changes due to diet/caloric restriction predominately in lysosomal markers including increased TFE3, FLCN, FNIP2, and pAMPK.
Results support that hippocampal ALP is a target of obesity and that sex shapes molecular responses, while providing insight into how dietary manipulations affect learning and memory based on sex.
Abstract
Xylem is a complex tissue that forms the bulk of tree bodies and has several functions, including to conduct water, store water and nutrients, and biomechanically support the plant body. We ...examined how xylem functional traits varied at different positions within 9-year-old Populus balsamifera subsp. trichocarpa. Whole trees were excavated, and xylem samples were collected at 1-m increments along the main root-to-shoot axis of six trees, from root tip to shoot tip. We examined biomechanical and water-storage traits of the xylem, including using a non-invasive imaging technique to examine water content within long, intact branches (high-resolution computed tomography; microCT). Xylem density, strength, and stiffness were greater in shoots than roots. Along the main root-to-shoot axis, xylem strength and stiffness were greatest at shoot tips, and the tissue became linearly weaker and less stiff down the plant and through the root. Roots had greater water storage with lower biomechanical support, and shoots had biomechanically stronger and stiffer xylem with lower water storage. These findings support trade-offs among xylem functions between roots and shoots. Understanding how xylem functions differ throughout tree bodies is important in understanding whole-tree functioning and how terrestrial plants endure numerous environmental challenges over decades of growth.
Xylem biomechanics and water storage differ greatly between woody roots and stems within an angiosperm tree species, with roots having greater water storage and reduced biomechanical support relative to stems.
Eusocial living influences mating system evolution if kin selection selects for a low number of fathers to increase helper relatedness and helping incentive. Consequently, polyandry resulting in pre- ...and postcopulatory sexual selection is restricted in social compared to nonsocial species. Despite a growing body of literature, empirical studies are still needed to understand fully the effects of kin selection on mating system evolution or vice versa. Here we review the mating biology of termites and conclude that they make interesting study species to unravel the evolutionary interplay between mating system evolution and eusociality. A number of reproductive characteristics of termites differ substantially from those of other insects. Polyandry appears to be mostly absent in termites and lifetime pair formation is achieved early in life, after an initial dispersal flight. The consequent absence of postcopulatory sexual selection coincides with the loss of a number of reproductive traits, such as elaborate male and female genitalia, flagellated sperm and seminal fluid-producing male accessory glands. The absence of sexually selected, female-harming male traits suggests that the interests of males and females are well aligned in most termites, fostering the evolution of kings, males with life expectancies comparable to those of queens and the ability to supply sperm continuously. Comparative work on mating system evolution between the diplodiploid termites and the haplodiploid hymenopteran social insects can be used to explain the influence of kin selection. We conclude that the study of social insect reproduction offers exciting opportunities to understand the evolutionary interplay between sexual, natural and kin selection.
► We compare mating biology of termites with that of Hymenoptera. ► Termites have evolved reproductive traits that are otherwise rare in animals. ► Sexual selection seems not a major evolutionary force in many termites. ► Termites allow us to study effects of natural selection on reproductive traits.
Multiple mating (and insemination) by females with different males, polyandry, is widespread across animals, due to material and/or genetic benefits for females. It reaches particularly high levels ...in some social insects, in which queens can produce significantly fitter colonies by being polyandrous. It is therefore a paradox that two thirds of eusocial hymenopteran insects appear to be exclusively monandrous, in spite of the fitness benefits that polyandry could provide. One possible cost of polyandry could be sexually transmitted parasites, but evidence for these in social insects is extremely limited. Here we show that two different species of Nosema microsporidian parasites can transmit sexually in the honey bee Apis mellifera. Honey bee males that are infected by the parasite have Nosema spores in their semen, and queens artificially inseminated with either Nosema spores or the semen of Nosema-infected males became infected by the parasite. The emergent and more virulent N. ceranae achieved much higher rates of infection following insemination than did N. apis. The results provide the first quantitative evidence of a sexually transmitted disease (STD) in social insects, indicating that STDs may represent a potential cost of polyandry in social insects.
Evolutionary ecologists are traditionally gene-focused, as genes propagate phenotypic traits across generations and mutations and recombination in the DNA generate genetic diversity required for ...evolutionary processes. As a consequence, the inheritance of changed DNA provides a molecular explanation for the functional changes associated with natural selection. A direct focus on proteins on the other hand, the actual molecular agents responsible for the expression of a phenotypic trait, receives far less interest from ecologists and evolutionary biologists. This is partially due to the central dogma of molecular biology that appears to define proteins as the ‘dead-end of molecular information flow’ as well as technical limitations in identifying and studying proteins and their diversity in the field and in many of the more exotic genera often favored in ecological studies. Here we provide an overview of a newly forming field of research that we refer to as ‘Evolutionary Proteomics’. We point out that the origins of cellular function are related to the properties of polypeptide and RNA and their interactions with the environment, rather than DNA descent, and that the critical role of horizontal gene transfer in evolution is more about coopting new proteins to impact cellular processes than it is about modifying gene function. Furthermore, post-transcriptional and post-translational processes generate a remarkable diversity of mature proteins from a single gene, and the properties of these mature proteins can also influence inheritance through genetic and perhaps epigenetic mechanisms. The influence of post-transcriptional diversification on evolutionary processes could provide a novel mechanistic underpinning for elements of rapid, directed evolutionary changes and adaptations as observed for a variety of evolutionary processes. Modern state-of the art technologies based on mass spectrometry are now available to identify and quantify peptides, proteins, protein modifications and protein interactions of interest with high accuracy and assess protein diversity and function. Therefore, proteomic technologies can be viewed as providing evolutionary biologist with exciting novel opportunities to understand very early events in functional variation of cellular molecular machinery that are acting as part of evolutionary processes.
Adenosinergic activities are suggested to participate in SUDEP pathophysiology; this study aimed to evaluate the adenosine hypothesis of SUDEP and specifically the role of adenosine A
2A
receptor (A
...2A
R) in the development of a SUDEP mouse model with relevant clinical features. Using a combined paradigm of intrahippocampal and intraperitoneal administration of kainic acid (KA), we developed a boosted-KA model of SUDEP in genetically modified adenosine kinase (ADK) knockdown (Adk
+/-
) mice, which has reduced ADK in the brain. Seizure activity was monitored using video-EEG methods, and
in vivo
recording of local field potential (LFP) was used to evaluate neuronal activity within the nucleus tractus solitarius (NTS). Our boosted-KA model of SUDEP was characterized by a delayed, postictal sudden death in epileptic mice. We demonstrated a higher incidence of SUDEP in Adk
+/-
mice (34.8%) vs. WTs (8.0%), and the ADK inhibitor, 5-Iodotubercidin, further increased SUDEP in Adk
+/-
mice (46.7%). We revealed that the NTS level of ADK was significantly increased in epileptic WTs, but not in epileptic Adk
+/-
mutants, while the A
2A
R level in NTS was increased in epileptic (WT and Adk
+/-
) mice vs. non-epileptic controls. The A
2A
R antagonist, SCH58261, significantly reduced SUDEP events in Adk
+/-
mice. LFP data showed that SCH58261 partially restored KA injection-induced suppression of gamma oscillation in the NTS of epileptic WT mice, whereas SCH58261 increased theta and beta oscillations in Adk
+/-
mutants after KA injection, albeit with no change in gamma oscillations. These LFP findings suggest that SCH58261 and KA induced changes in local neuronal activities in the NTS of epileptic mice. We revealed a crucial role for NTS A
2A
R in SUDEP pathophysiology suggesting A
2A
R as a potential therapeutic target for SUDEP risk prevention.
This unprecedented book examines the explosion of homosexual discourse in post-Soviet Russia from the turbulent years of the immediate post-communist era through the more troubling recent ...developments of Vladimir Putin's regime. Focusing on concepts of sexuality, gender, and national identity within competing portrayals of same-sex desire, Brian James Baer explores a variety of popular media, including fiction, film, television, music, and print to detail how homosexuality in today's Russia has come to signify a surprising and often contradictory array of uniquely post-Soviet concerns. Summary reprinted by permission of Palgrave Macmillan
This paper presents new lower and upper bounds for the compression rate of binary prefix codes optimized over memoryless sources according to various nonlinear codeword length objectives. Like the ...most well-known redundancy bounds for minimum average redundancy coding-Huffman coding-these are in terms of a form of entropy and/or the probability of an input symbol, often the most probable one. The bounds here, some of which are tight, improve on known bounds of the form L ∈ H , H +1), where H is some form of entropy in bits (or, in the case of redundancy objectives, 0) and L is the length objective, also in bits. The objectives explored here include exponential-average length, maximum pointwise redundancy, and exponential-average pointwise redundancy (also called d th exponential redundancy). The first of these relates to various problems involving queueing, uncertainty, and lossless communications; the second relates to problems involving Shannon coding and universal modeling. Also explored here for these two objectives is the related matter of individual codeword length.
Global pollinator declines threaten food production and natural ecosystems. The drivers of declines are complicated and driven by numerous factors such as pesticide use, loss of habitat, rising ...pathogens due to commercial bee keeping and climate change. Halting and reversing pollinator declines will require a multidisciplinary approach and international cooperation. Here, we summarize 20 presentations given in the symposium ‘Protecting pollinators and our food supply: Understanding and managing threats to pollinator health’ at the 19th Congress of the International Union for the Study of Social Insects in San Diego, 2022. We then synthesize the key findings and discuss future research areas such as better understanding the impact of anthropogenic stressors on wild bees.
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