Geriatric infections: Decreased immunity or evolved opportunists?

In host–parasite co-evolution, parasites are assumed to have an advantage owing to their shorter generationtime. Evolution of pathogens within the lifetime of a host individual is implicated as a strong selective force inthe evolution of sex and aging in the host. However, this assumption or its testable predictions have not beenexamined empirically. We classified infectious bacteria and viruses into those that can have continued longterm existence on the host body (group 1) versus those that have only a short-term interaction during an activeinfection (group 2). We surveyed the literature for age-specific incidence data about infections from both thegroups. The age trends of the two groups show contrasting patterns. The incidence of infections by all group 1pathogens showed a 2.28- to 28-fold increase in older ages. In group 2, 6 out of the 9 pathogens showed asignificant declining trend in incidence with age. In both groups, there was greater mortality or morbidityamong the infected in the old-age classes. These patterns are better explained by pathogen evolution than byage-related decline in immunity

Biting the hand that feeds you: wedge-billed hummingbird is a nectar robber of a sicklebill-adapted Andean bellflower / Muerde la mano que le da de comer: Colibrí pico cuña el ladrón de néctar de Centropogon granulosus (Campanulaceae)

Informo sobre el comportamiento de robo de néctar del colibrí pico cuña, Schistes geoffroyi (Trochilidae) en la flor campanulada neotropical, Centropogon granulosus (Campanulaceae). Muchas especies de Centropogon se caracterizan por tener una flor tubular curvada de distintas formas y probablemente especializadas para ser polinizadas por los colibríes de pico curvo (Eutoxeres), como es evidente a partir de la curvatura tanto de la flor como del pico. Debido a la exclusividad de este mutualismo, el robo de néctar ha sido ocasionalmente documentado en Centropogon. Aquí amplío el estudio de robo de néctar de Centropogon incluyendo a Schistes geoffroyi. Esta expansión puede ser un indicador de la alta especialización entre el mutualismo de Centropogon y el colibrí de pico curvo, siendo esta más susceptible al robo de néctar de lo que pensaba previamente. Esto genera preguntas acerca de la evolución de la especialización y parasitismo en este grupo tropical, tanto de las campanuladas como de los colibríes.

I report on nectar robbing behavior of the wedge-billed hummingbird, Schistes geoffroyi (Trochilidae) on the Andean bellflower, Centropogon granulosus (Campanulaceae). Many species of Centropogon are characterized by an abruptly curved corolla tube which is likely specialized for pollination by sicklebill hummingbirds (Eutoxeres), as evident from the matching curvature of flower and bill. Nectar robbing has been documented for some Centropogon spp., but not for sicklebill pollinated C. granulosus. Given recent developments and interest in the Centropogon-sicklebill mutualism, it is pertinent to document any natural history observations that may underlie the ecology and evolution of this pollination system. The establishment of wedge-billed hummingbird as a nectar robber of C. granulosus calls for a new assessment of the ecology and evolution of the highly specialized Centropogon-sicklebill mutualism.

Taxonomy of the Golovinomyces cynoglossi Complex (Erysiphales, Ascomycota) Disentangled by Phylogenetic Analyses and Reassessments of Morphological Traits

The name Golovinomyces cynoglossi s. lat. is traditionally applied to a complex of morphologically similar powdery mildews on hosts of the plant family Boraginaceae. The current species-level taxonomy within this complex is ambiguous due to the lack of phylogenetic examinations. The present study applied phylogenetic methods to clarify the taxonomy of G. cynoglossi s. lat. Phylogenetic analysis of rDNA ITS sequences retrieved from Asian, European and North American specimens revealed that G. cynoglossi s. lat. collections from different hosts involved several species in five clearly separated lineages. Clade I consists primarily of Golovinomyces cynoglossi s. str. on Cynoglossum. Clade III consists of Golovinomyces sequences retrieved from the host genera Symphytum and Pulmonaria. The taxa within clade III are now assigned to G. asperifoliorum comb. nov. Clade V encompasses G. cynoglossi s. lat. on the host genera Bothriospermum, Buglossoides, Echium, Myosotis, and Trigonotis. The taxa within clade V are now assigned to G. asperifolii comb. nov. The species concerned in this study were lecto- and epitypified to stabilize their nomenclature.

Seed germination after passing through gastrointestinal tract of bats (Chiroptera, Phyllostomidae) / Germinação de sementes após a passagem pelo trato gastrointestinalde morcegos (Chiroptera, Phyllostomidae)

Este estudo teve como objetivo avaliar a germinação de sementes de espécies de Piper, Solanum, Cecropiae Fícus após sua passagem pelo trato gastrointestinal dos morcegos frugívoros Artibeus lituratus, Platyrrhinus lineatus, Carollia perspicillata e Sturnira lilium. Os morcegos e as amostras de frutos/infrutescências foram obtidos no Parque Estadual Mata dos Godoy, Londrina, PR. Para cada espécie vegetal foram considerados o controle e quatro tratamentos, formados pelas sementes obtidas das fezes de cada espécie de morcego: (1) A. lituratus, (2) P. lineatus, (3) C. perspilata e (4) S. lilium. Duzentas sementes foram utilizadas em cada tratamento e foram colocadas para germinar, ao mesmo tempo, em quatro recipientes distribuídos aleatoriamente. Os dados de germinação foram usados para calcular a taxa e o tempo médio de germinação. Somente em duas espécies, Cecropia pachystachya e Ficus eximia, apassagem através do trato gastrointestinal dos animais não produziu alteração significativa. Enquanto, asseis espécies restantes obtiveram diferenças significativas nas taxas e/ou tempos médio de germinação de sementes após passagem dos diásporos pelo trato gastrointestinal de pelo menos uma das espécies de morcegos. Além disso, foi possível observar que a preferência alimentar da espécie de morcego por uma espécie vegetal não alterou significativamente a germinação em relação aos demais. Conclui-se que ao longo do processo evolutivo a coevolução difusa não favoreceu a alteração de padrões de germinação pela preferência alimentar dos morcegos. Todavia, foi observado que os morcegos alteram a taxa e o tempo de germinação das plantas, auxiliando seu estabelecimento, além de serem bons dispersores,mesmo das espécies onde a germinação não foi alterada.

The aim of this study was to evaluate seed germination of Piper, Solanum, Cecropia and Ficus speciesafter their passage through the gastrointestinal tract of frugivorous bats - Artibeus lituratus, Platyrrhinuslineatus, Carollia perspicillata and Sturnira lilium. Both bats and fruits/infrutescences samples were obtained in the Parque Estadual Mata do Godoy, Londrina, Brazil. For each plant species, we considered the control and four treatments, made up by the seeds obtained from the feces of each species of bat:(1) A. lituratus, (2) P. lineatus, (3) C. perspilata and (4) S. lilium. Two hundred seeds were used for each treatment and were germinated at the same time, randomly distributed in four containers. The germination data were used to calculate the rate and the average germination time. In only two species, C. pachystachya and F. eximia, the passage through the gastrointestinal tract of animals produced no significant change. While the remaining six species had significant differences in the rates and / oraverage time of seed germination after passage through the gastrointestinal tract of at least one speciesof bats. Moreover, food preference of bat species for one plant species did not significantly change seed germination in relation to other plants. The conclusion is that over evolutionary process, diffuseco-evolution did not favor changing germination standards for food preference of bats. However, it was observed that bats modify the rate and germination time of plants assisting its establishment, besides being good dispersers, even of the species where germination has not been changed.

Progress of research on parasitic adaptability of schistosome and its applica-tion value / 中国血吸虫病防治杂志

The larval and adult schistosomes can effectively establish the stable parasitic relationship with their final hosts and then maintain the parasitism for a long time,due to the successful adaptation to their parasitic lifestyle. This paper reviews the progress of research on parasitic adaptability of schistosomes in several respects,and demonstrates the application value of schisto-somal genes related to parasitic adaptability in schistosomiasis control and exploitation of natural active molecules.

Biologia, subjetividade e alteridade / Biology, subjectivity and alterity / Biología, subjetividad y alteridad

Este artigo tem a finalidade de apresentar e discutir o conceito de alteridade biológica. A questão da alteridade, do ponto de vista humano, se expressa além da dimensão abordada pela biologia; mas a faculdade de realizar escolhas conscientes e de se constituir na relação com o outro, teria uma raiz na biologia e estaria inscrita na existência de todo ser vivo. Estudos recentes da biologia e da filosofia apontam para novas formas de pensar a relação entre os seres vivos do ponto de vista ontogênico e coevolutivo. A condição humana é anteriormente biológica. Conceber a alteridade, enquanto natureza peculiar dos seres vivos, pode apontar para uma forma diferente e integrada de se compreender o corpo humano e as questões éticas relativas ao vivo e às práticas em saúde.

This article aims to present and discuss the concept of biological alterity. From a human point of view this issue is expressed beyond the dimension approached by biology. However, the ability to make conscious decisions and be constituted in the relationship with the other would have a biological root and would be embedded in the existence of every living being. Recent biology and philosophy studies have shown new ways of thinking about the relation among living beings from the point of view of ontogeny and co-evolution. The human condition has primarily biological origins. Addressing alterity as a peculiar nature of the living beings may indicate a different and integrated way of understanding human body as well as the ethical issues related to life and health practices.

Este artículo tiene la finalidad de presentar y discutir el concepto de alteridad biológica. La cuestión de la alteridad, del punto de vista humano, se expresa más allá de la dimensión planteada por la biología; pero la facultad de realizar escogimientos conscientes y de constituirse en la relación con el otro tendría una raíz en la biología y estaría inscrita en la existencia de todo ser viviente. Estudios recientes de la biología y de la filosofía apuntan para nuevas formas de pensar la relación entre los seres vivientes del punto de vista ontogénico y co-evolutivo. La condición humana es anteriormente biológica. Comprender la alteridad como naturaleza propia de los seres vivientes puede apuntar una forma integrada y diferente de comprender el cuerpo humano y las cuestiones éticas relativas al viviente y a las prácticas en salud.

Pneumocystis diversity as a phylogeographic tool

Parasites are increasingly used to complement the evolutionary and ecological adaptation history of their hosts. Pneumocystis pathogenic fungi, which are transmitted from host-to-host via an airborne route, have been shown to constitute genuine host markers of evolution. These parasites can also provide valuable information about their host ecology. Here, we suggest that parasites can be used as phylogeographic markers to understand the geographical distribution of intra-specific host genetic variants. To test our hypothesis, we characterised Pneumocystis isolates from wild bats living in different areas. Bats comprise a wide variety of species; some of them are able to migrate. Thus, bat chorology and migration behaviour can be approached using Pneumocystis as phylogeographic markers. In the present work, we find that the genetic polymorphisms of bat-derived Pneumocystis are structured by host chorology. Therefore, Pneumocystis intra-specific genetic diversity may constitute a useful and relevant phylogeographic tool.

Specificity of Developmental Resistance in Gypsy Moth (Lymantria dispar) to two DNA-Insect Viruses / 中国病毒学·英文版

Gypsy moth (Lymantria dispar) larvae displayed marked developmental resistance within an instar to L. dispar M nucleopolyhedrovirus (LdMNPV) regardless of the route of infection (oral or intrahemocoelic) in a previous study, indicating that in gypsy moth, this resistance has a systemic component.In this study, gypsy moth larvae challenged with the Amsacta moorei entomopoxvirus (AMEV) showed developmental resistance within the fourth instar to oral, but not intrahemocoelic, inoculation. In general, gypsy moth is considered refractory to oral challenge with AMEV, but in this study, 43% mortality occurred in newly molted fourth instars fed a dose of 5×106 large spheroids of AMEV; large spheroids were found to be more infectious than small spheroids when separated by a sucrose gradient. Developmental resistance within the fourth instar was reflected by a 2-fold reduction in mortality (18%-21%) with 5×106 large spheroids in larvae orally challenged at 24, 48 or 72 h post-molt. Fourth instars were highly sensitive to intrahemocoelic challenge with AMEV; 1PFU produced approximately 80% mortality regardless of age within the instar. These results indicate that in gypsy moth, systemic developmental resistance may be specific to LdMNPV, reflecting a co-evolutionary relationship between the baculovirus and its host.

Pathogenetic Consequences of Cytomegalovirus-Host Co-evolution / 中国病毒学·英文版

Co-evolution has been shown to result in an adaptive reciprocal modification in the respective behaviors of interacting populations over time.In the case of host-parasite co-evolution,the adaptive behavior is most evident from the reciprocal change in fitness of host and parasite-manifested in terms of pathogen survival versus host resistance.Cytomegaloviruses and their hosts represent a pairing of populations that has co-evolved over hundreds of years.This review explores the pathogenetic consequences emerging from the behavioral changes caused by co-evolutionary forces on the virus and its host.