The Hyperfunction Theory: An Emerging Paradigm for the Biology of Aging

The process of senescence (aging) is largely determined by the action of wild-type genes. For most organisms, this does not reflect any adaptive function of senescence, but rather evolutionary effects of declining selection against genes with deleterious effects later in life. To understand aging requires an account of how evolutionary mechanisms give rise to pathogenic gene action and late-life disease, that integrates evolutionary (ultimate) and mechanistic (proximate) causes into a single explanation. A well-supported evolutionary explanation by G.C. Williams argues that senescence can evolve due to pleiotropic effects of alleles with antagonistic effects on fitness and late-life health (antagonistic pleiotropy, AP). What has remained unclear is how gene action gives rise to late-life disease pathophysiology. One ultimate-proximate account is T.B.L. Kirkwood’s disposable soma theory. Based on the hypothesis that stochastic molecular damage causes senescence, this reasons that aging is coupled to reproductive fitness due to preferential investment of resources into reproduction, rather than somatic maintenance. An alternative and more recent ultimate-proximate theory argues that aging is largely caused by programmatic, developmental-type mechanisms. Here ideas about AP and programmatic aging are reviewed, particularly those of M.V. Blagosklonny (the hyperfunction theory) and J.P. de Magalhães (the developmental theory), and their capacity to make sense of diverse experimental findings is described.

Developmental innovations promote species diversification in mushroom-forming fungi

Fungi evolved complex fruiting body (‘mushroom’) morphologies as adaptations to efficient spore dispersal in terrestrial habitats. Mushroom-forming fungi (Agaricomycetes) display a graded series of developmental innovations related to fruiting body morphology, however, how these evolved is largely unknown, leaving the functional biology and evolutionary principles of complex multicellularity in the third largest multicellular kingdom poorly known. Here, we show that developmental innovations of mushroom-forming fungi that enclose the spore-producing surface (hymenophore) in a protected environment display significant asymmetry in their evolution and are associated with increased diversification rates. ‘Enclosed’ development and related tissues (partial and universal veils) evolved convergently and became a widespread developmental type in clades in which it emerged. This probably mirrors increased fitness for protected fruiting body initials in terrestrial habitats, by better coping with environmental factors such as desiccation or predators, among others. We observed similar patterns in the evolution of complex hymenophore architectures, such as gills, pores or teeth, which optimize biomass-to-propagule number ratios and were found to spur diversification in mushrooms. Taken together, our results highlight new morphological traits associated with the adaptive radiation of mushroom-forming fungi and present formal phylogenetic testing of hypotheses on the reproductive ecology of a poorly known but hyperdiverse clade.

Targeted Poverty Alleviation and Households’ Livelihood Strategy in a Relation-Based Society: Evidence from Northeast China

Although China is experiencing a transition from a relation-based society to a rule-based society, relationships among acquaintances still play an important role in resource allocation, such as the allocation of policy resources. This is particularly true in rural China, where targeted poverty alleviation is prevalent and a relation-based social structure still dominates. However, it is still unknown how relationships affect the livelihood strategy of households in rural China and how poverty alleviation policies plays a role between them. Therefore, this paper embeds poverty alleviation into the relation-based society and explores how households respond to the policy in this specific context. Using grounded theory research method and the sustainable livelihoods approach (SLA) framework, this paper contains in-depth interviews and field observations from three poverty-stricken villages in Northeast China. The results show that relationships have a significant impact on the households’ livelihood strategy. In other words, the households’ livelihood strategy is embedded in the relation-based society. The types of relationships induce households to choose maintained or developmental type livelihood strategies, while relationships influence how the poverty alleviation policies affect the livelihood strategy. This study is not only an extension of the SLA in the research context, but also provides a significant perspective for enriching the long-term mechanism of targeted poverty alleviation by building a theoretical model of the relationships between a relation-based society, targeted poverty alleviation and the livelihood strategies of households.

Study of stress and stress resistance of preschool staff organizations: hygiene aspects

The article deals with the problem of professional stress in the labor activity of employees of preschool educational organizations. Aim. The level of stress and stress resistance of preschool teachers was assessed. In accordance with the purpose of the study, the following methods were used: T.A. Nemchina, A.O. Prokhorov, Vaisman's questionnaire, McLean. The study involved 50 teachers of kindergartens of general developmental type. The materials of modern psychological and pedagogical research devoted to stress and stress resistance are analyzed and summarized. Experimental data on the state of stress resistance of preschool teachers have been obtained. In a preschool organization, employees need to reduce the level of neuropsychiatric stress, professional and organizational stress, since most of the subjects are characterized by high indicators for these parameters.

Characteristics of Developmental Differences between Fertile and Aborted Ovules in Camellia oleifera

Camellia oleifera is an important woody edible oil plant in southern China. In this study, the developmental differences in ovules at different positions in the ovary of C. oleifera were observed. The developmental type and characteristics of aborted ovules, ratios of normal and aborted ovules, and their developmental differences after flowering were examined. Ovules near the stylar end and in the middle exhibit normal development and are able to form embryo sacs; lower ovules near the pedicel end are usually aborted. The proportion of abortion of four examined cultivars ranges from 10.2% to 33.3%. Aborted ovules can be divided into four categories: 1) nascent egg apparatus lacking distinguishable cells; 2) completely absent egg apparatus structure consisting of flocculent tissue; 3) lack of tissue, comprising only integument cells; and 4) the inner integument not constituting a micropyle channel, with incomplete egg apparatus development and generating abnormal ovules. At 120 days after pollination (DAP), significant distinguishable size differences were found between fertile and aborted ovules; aborted ovules ceased growth at 180 DAP. On fruit maturation, aborted seeds were still attached to the placenta.

Flowers

This chapter focuses on the developmental evolution of flowers and flower organ identity. It reviews some of the most important insights that have been gained from research on the developmental evolution of flowers regarding the nature of organ identity, organ integration, and the origin of evolutionary novelties. The chapter begins with a discussion of the uniqueness of flowers and the evolution of phylogeny and flower characters in angiosperms. It then examines the genetics of canonical flower development, along with the developmental genetic architecture of the flower Bauplan. It also considers flower variation and the identities of novel flower organs, the origin of the bisexual flower developmental type, perianth evolution and the origin of petals, and the realization that additional organ identities can evolve after gene duplications.

Feeding Potential in the Lecithotrophic Larvae of Adalaria Proxima and Tritonia Hombergi: An Evolutionary Perspective

Vance (1973a, b) argued that among the possible range of developmental strategies available to marine invertebrates, only the extremes of obligate planktotrophy and obligate lecithotrophy are evolutionarily stable. Vance's model, relating reproductive 'efficiency' to egg size (in terms of energetic content), predation rate, and prefeeding (lecithotrophic) vs feeding (planktotrophic) larval periods, has been a source of much discussion and debate since its inception (e.g. Underwood, 1974; Vance, 1974; Christiansen & Fenchel, 1979; Obrebski, 1979; Williams, 1980; Jablonski & Lutz, 1983; Strathmann, 1978, 1985; Todd, 1985). Subsequent publications have continued to dwell mainly on potential selective factors and the extremes of larval developmental type (i.e. obligate planktotrophy or obligate non-pelagic lecithotrophy). For the most part, these investigations have ignored questions concerning how a transition from one larval type to another would be accomplished in morphological and functional terms. Nonetheless, the consensus persists that small eggs and planktotrophy are the primitive (or ancestral) condition, and that lecithotrophy is the more advanced evolutionary derivative (see Strathmann, 1978,1985).

Scanning electron microscopy of the ontogeny of Ampelomyces quisqualis pycnidia

Observations on Ampelomyces quisqualis disclosed that the pycnidium may originate either from one cell of a single pycnidiospore, or from one hyphal cell. In the first case the pycnidiospore becomes two celled and swollen and a profuse germination of one of the two swollen spore cells can be observed. Later, the short hyphae branches, interweave, and anastomose to form a compact network around the mother spore, the pycnidium primordium. Similarly, we observed profuse branching in a single hyphal cell. The newly formed branches interweave and anastomose to form a compact network which gives rise to the pycnidium primordium. Hyphal rings were also observed throughout this study, but no pycnidia arose from these structures. During the vegetative growth of the fungus, hyphal anastomosis seems to be a frequent pattern. It seems that the pycnidial ontogeny of A. quisqualis does not conform to any known developmental type.