In the parthenogenetic monogeneans of the genus Gyrodactylus Nordmann, 1832, the genetic diversity within or between hosts is determined by the relative roles of lateral transmission and clonal propagation. Clonality and limited transmission lead to high-amplitude metapopulation dynamics and strong genetic drift. In Baltic populations of the three-spined stickleback Gasterosteus aculeatus Linnaeus, the local mitochondrial diversity of Gyrodactylus arcuatus Bychowsky, 1933 is very high, and spatial differentiation weak. To understand the transmission dynamics in a single location, the transmission of the parasite from adults to next generation sticklebacks was investigated in a northern Baltic brackish water location. By sequencing 777 nt of cox1, as many as 38 separate mitochondrial haplotypes were identified. In August, the intensity of gyrodactylid infection on adult hosts was high, the haplotype diversity (h) was extreme and differentiation between fish was negligible (total h = 0.926, mean h = 0.938). In October, only 46% of the juvenile sticklebacks carried G. arcuatus. The number of parasites per young fish followed a Poisson distribution 0.92 ± 1.04 (mean ± SD) on October 2, and was clearly overdispersed 2.38 ± 5.00 on October 25. The total haplotype diversity of parasites on juveniles was nearly as high as in adults (h = 0.916), but the mean per fish was only h = 0.364 (FST = 0.60), due to low intensity of infection and rapid clonal propagation of early arrivals. The initial first come first served advantage of the first gyrodactylid colonisers will be lost during the host adulthood via continuous transmission. Nesting and polygamy are suggested as factors maintaining the high genetic diversity of the parasite population. The transmission dynamics and, consequently, the population structure of Baltic G. arcuatus is fundamentally different from that of G. salaris Malmberg, 1957, on the Baltic salmon Salmo salar Linnaeus., Jaakko Lumme, Marek S. Ziętara., and Obsahuje bibliografii
The morphology, physiology, behaviour and ecology of spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) on different host plants differ greatly. The genetic differences between the A. dispersus populations on 17 host plants were evaluated in the current study. Microsatellite markers were used to identify the presence of host-related genetic variation among A. dispersus populations. Our research clearly shows that there is a significant amount of genetic divergence among the A. dispersus populations on 17 host plants in India. The spiralling whitefly on acalypha and calotropis were genetically more distinct than whiteflies on other host plants. Various population genetic parameters, like heterozygosity, Nei's genetic distance, fixation indices (FST), source of genetic variation in AMOVA, etc. indicate that populations of spiralling whiteflies differ greatly genetically, probably because the spiralling whitefly populations on the Indian sub-continent came from multiple sources. The results of this study have implications for the quarantine protection strategy against this invasive pest.
Myxobolus filamentum sp. n. was found infecting gill filaments of three of 39 Brycon orthotaenia Günther specimens examined (8%), which were taken from the river São Francisco in Minas Gerais state, Brazil. Plasmodia of the parasite were white and long, measuring 5 mm in lenght. Mature spores of M. filamentum sp. n. were oval from the frontal view and biconvex from the lateral view, measuring 7.5-9.7 µm (9.0 ± 0.3 µm) in length and 5.2-7.3 µm (6.2 ± 0.4 µm) in width. The polar capsules were elongated and equal in size, measuring 3.8-5.5 µm (4.7 ± 0.3 µm) in length and 1.3-2.2 µm (1.7 ± 0.1 µm) in width. The development of the parasite led to compression of the adjacent tissues and inflammatory infiltrate with granulocytic cells. Ultrastructural observation revealed that the plasmodia were delimited by two membranes, which had numerous and extensive pinocytotic channels extending into the wide ectoplasm zone. The plasmodial wall exhibited abundant villi-like projections and a thin layer of granular material prevented direct contact between the plasmodial wall and the host tissue. Phylogenetic analysis, based on 18S rDNA, showed M. filamentum sp. n. as a sister species of Myxobolus oliveirai Milanin, Eiras, Arana, Maia, Alves, Silva, Carriero, Ceccarelli et Adriano, 2010, a parasite of other fish species of the genus Brycon Müller et Troschel from South America., Juliana Naldoni, Suellen A. Zatti, Kassia R.H. Capodifoglio, Tiago Milanin, Antônio A.M. Maia, Marcia R.M. Silva, Edson A. Adriano., and Obsahuje bibliografii
Preferences of young caterpillars of three species of Pieris (P. rapae crucivora Boisduval, P. melete Ménétriès, and P. napi japonica Shirôzu) (Lepidoptera: Pieridae) for the upper and lower surfaces of the leaves of their host plants (Brassicaceae) were investigated in the laboratory. On horseradish Armoracia rusticana Gaertn. Mey. et Scherb., which was provided as a common food for three species, second and third instar larvae of the respective species preferred the lower to the upper surface of horizontally placed leaves, irrespective of whether they hatched on the upper or lower surface. First instar larvae seemed to remain on the surface on which they hatched. However, first instar larvae of P. melete on Rorippa indica (L.), a natural food of P. melete in the field, and first instar larvae of P. napi japonica on Arabis flagellosa Miq., a natural food of P. napi japonica, preferred the lower to the upper surface, just as second and third instar larvae did. To elucidate the effects of leaf-surface preference, the percentage parasitism of P. rapae crucivora on Arm. rusticana and Ara. flagellosa by the parasitoid Cotesia glomerata (L.) (Hymenoptera: Braconidae) was investigated. On Arm. rusticana, the percentage parasitism of the larvae on the upper surface was higher than that of larvae on the lower surface. On Ara. flagellosa, however, percentages parasitism were nearly equal on both surfaces. Leaf-surface preference by the larvae of Pieris is discussed in terms of avoidance of parasitism by the parasitoid C. glomerata.
This paper explores the ways in which housing wealth is producing new forms of differentiation among households. In doing so, it will argue that ‘asset based welfare’ is now better conceived as ‘asset based social stratification’ and that social class rather than generation remains the primary social divide. However, these class divides are increasingly shaped by the differential ability to accumulate and deploy primarily housing -based assets. These new forms of social (re) stratification will vary societally, temporally and spatially and are currently most evident in what can be described as older, mature home ownership societies. But similar developments and emerging fissures can be observed in newer, ultra home -ownership societies such as China and in the broader interconnections between the mobilization of family assets and the shift from consumer to market societies.
The Portuguese housing market underwent major transformations between 2010 and 2020. Until then, a delicate but resentful stability had long existed, with distorted rent schemes and low annual price increases proportional to the national economy and the income of the Portuguese population. After the financial crisis, several internal and external variables converged to dramatically change this scenario. In recent years, a growing number of researchers have centred their attention on the difficulties that the Portuguese urban middle-class populations are facing in trying to find homes. This paper analyses these challenges and their impact quantitatively, focusing on the affordability of housing for purchase or rent and considering synthetic indicators for average household incomes in the Lisbon Metropolitan Area between the beginning of 2016 and the end of 2019. The results show that the cost of buying or renting a house in the main Portuguese urban system has become much more detached from local incomes. The article concludes with reflections on the structural reasons for the enduring inequalities in the housing markets and the difficulties recognising territorial cohesion and spatial justice as important elements shaping urban and housing policies in Portugal.
Copepods of the genus Achtheinus Wilson, 1908 (Pandaridae) are parasites of elasmobranchs that attach to their fins, gill slits and around the nostrils. Specimens of Achtheinus pinguis Wilson, 1912 were collected and examined using histology and scanning electron microscopy to determine their way of attachment to the host and the possible effect on the host. They insert their antennae deep into the dermis of the shark's skin, which causes the most damage due to possible tissue compression and/or fibrosis as well as rupture of the connective tissue. Additionally, the presence of the copepod on the skin causes cell erosion of the epidermal cells and thus reduces the number of epidermal layers. The maxillipeds are used to attach to the placoid scales that cover the shark's skin and probably serve to keep the copepod and inserted antennae in position. This is accomplished by the insertion of the placoid scales into the flaccid corpus of the maxillipeds. Observed damage seems to be negligible to the shark apart from the possibility of secondary infection., Susan M. Dippenaar, Anine Jordaan., and Obsahuje bibliografii
The whipworms, i.e. parasitic nematodes of the genus Trichuris Roederer, 1761, infect a variety of mammals. Apparently low diversity of primate-infecting species of Trichuris strongly contrasts with the high number of species described in other mammalian hosts. The present study addresses the diversity of whipworms in captive and free-ranging primates and humans by analysing nuclear (18S rRNA, ITS2) and mitochondrial (cox1) DNA. Phylogenetic analyses revealed that primate whipworms form two independent lineages: (i) the Trichuris trichiura (Linnaeus, 1771) clade comprised of genetically almost identical whipworms from human and other primates, which suggests the ability of T. trichiura to infect a broader range of primates; (ii) a clade containing primarily Trichuris suis Schrank, 1788, where isolates from human and various primates formed a sister group to isolates from pigs; the former isolates thus may represent of more species of Trichuris in primates including humans. The analysis of cox1 has shown the polyphyly of the genera Trichuris and Capillaria, Zeder, 1800. High sequence similarity of the T. trichiura isolates from humans and other primates suggests their zoonotic potential, although the extent of transmission between human and other non-human primates remains questionable and requires further study., Jana Doležalová, Miroslav Oborník, Eva Hajdušková, Milan Jirků, Klára J. Petrželková, Petra Bolechová, Cristina Cutillas, Rocio Callejón, Jozef Jaroš, Zuzana Beránková, David Modrý., and Obsahuje bibliografii
This paper describes the post-disaster reconstruction in the Tohoku region after the 2011 earthquake. Nine years have passed since the Great East Japan Earthquake and Tsunami occurred, and many efforts have been made since to rebuild the devastated territories. Some Japanese architects and urban planners have seen the recovery as a window of opportunity to aim for more resilient cities. Nevertheless, building disaster-resilient communities remains a challenging task. This short paper presents the initiatives made to improve refugees’ social conditions in disaster-relief housing, using the case study of Iwanuma’s relocation project. Concluding remarks suggest that many efforts have been made to improve the social aspect of disaster-relief housing in Japan, for example through the development of community spaces or the pursuit of friendlier dwellings.