Host-specificity, host-exclusivity, and host-recurrence in saprobic fungi

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

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Origin of host-specificity resistance genes of common wheat against non-adapted pathotypes of Pyricularia oryzae inferred from D-genome diversity in synthetic hexaploid wheat lines

Journal of General Plant Pathology ◽

10.1007/s10327-021-00990-2 ◽

2021 ◽

Author(s):

Yoshihiro Inoue ◽

Trinh Thi Phuong Vy ◽

Soichiro Asuke ◽

Yoshihiro Matsuoka ◽

Yukio Tosa

Keyword(s):

Host Specificity ◽

Common Wheat ◽

Resistance Genes ◽

Hexaploid Wheat ◽

Pyricularia Oryzae ◽

Synthetic Hexaploid Wheat ◽

Genome Diversity ◽

D Genome ◽

Synthetic Hexaploid ◽

Wheat Lines

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Distribution of the cestode Urocystis prolifer Villot, 1880 (Cyclophyllidea: Hymenolepididae) in the Palaearctic and new data on its postembryonic development

Journal of Helminthology ◽

10.1017/s0022149x21000249 ◽

2021 ◽

Vol 95 ◽

Author(s):

S.A. Kornienko ◽

L.A. Ishigenova

Keyword(s):

Host Specificity ◽

Geographical Distribution ◽

Experimental Infection ◽

Definitive Host ◽

Intestinal Parasite ◽

Geographic Area ◽

Postembryonic Development ◽

Generic Diagnosis ◽

Intermediate Hosts ◽

Very High

Abstract Urocystis prolifer Villot, 1880 is an intestinal parasite of Sorex spp. In the Palaearctic. There are significant differences in the descriptions of both adults and stages of ontogenesis of U. prolifer as described by various authors. The experimental infection of intermediate hosts with cestodes has been conducted. An overview of the geographical distribution, infestation of the definitive hosts and the development of the metacestode stages of U. prolifer are presented. The cestode is characterized by an extensive geographic area in the Palaearctic, wide host specificity and very high rates of infection of its definitive host. Urocystis prolifer has been recorded mostly in the taiga and forest zones of Palaearctic. Fourteen species of Sorex were registered as the definitive host. Redescription of U. prolifer and an amended generic diagnosis are provided. A complete description of the ontogeny from oncosphere to fully developed metacestode is given. Features of development of the metacestode are an asexual larval reproduction, the absence of the anterior and posterior obturator valve in the cyst of the fully developed urocyst, as well as excretory bodies.

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Novel Viruses That Lyse Plant and Human Strains of Kosakonia cowanii

Viruses ◽

10.3390/v13081418 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1418

Author(s):

Karel Petrzik ◽

Sára Brázdová ◽

Krzysztof Krawczyk

Keyword(s):

Host Specificity ◽

Opportunistic Pathogen ◽

New Genera ◽

Pathogen Control ◽

Plaque Phenotype

Kosakonia cowanii (syn. Enterobacter cowanii) is a highly competitive bacterium that lives with plant, insect, fish, bird, and human organisms. It is pathogenic on some plants and an opportunistic pathogen of human. Nine novel viruses that lyse plant pathogenic strains and/or human strains of K. cowanii were isolated, sequenced, and characterized. Kc166A is a novel kayfunavirus, Kc261 is a novel bonnellvirus, and Kc318 is a new cronosvirus (all Autographiviridae). Kc237 is a new sortsnevirus, but Kc166B and Kc283 are members of new genera within Podoviridae. Kc304 is a new winklervirus, and Kc263 and Kc305 are new myoviruses. The viruses differ in host specificity, plaque phenotype, and lysis kinetics. Some of them should be suitable also as pathogen control agents.

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