In the present report we study the proteolytic activity of the excretion-secretion and crude extracts of different stages of Trichinella spiralis (Owen, 1835) Railliet, 1895, (muscle-stage larvae, adult worms before and after mating, and newborn larvae) using natural substrates (structural and hematic mammalian proteins). The analysis of the results allow us to set up a certain stage-specificity, as well as an important relationship between the protease patterns throughout the parasite life cycle and how the parasite may overcome both mechanical and humoral barriers within the host. Muscle-stage larvae present a great activity against structural proteins (collagen), while newborn larvae and adult worms degrade principally hematic proteins (hemoglobin, fibrinogen and immunoglobulin G).
Oxidative stress is an imbalance between free radicals and antioxidants, and is an important etiological factor in the development of hypertension. Recent experimental evidence suggests that subpressor doses of angiotensin II elevate oxidative stress and blood pressure. We aimed to investigate the oxidative stress related mechanism by which a subpressor dose of angiotensin II induces hypertension in a normotensive rat model. Normotensive male Wistar rats were infused with a subpressor dose of angiotensin II for 28 days. The control group was sham operated and infused with saline only. Plasma angiotensin II and H2O2 levels, whole-blood glutathione peroxidase, and AT-1a, Cu/Zn SOD, and p22phox mRNA expression in the aorta was assessed. Systolic and diastolic blood pressures were elevated in the experimental group. There was no change in angiotensin II levels, but a significant increase in AT-1a mRNA expression was found in the experimental group. mRNA expression of p22phox was increased significantly and Cu/Zn SOD decreased significantly in the experimental group. There was no significant change to the H2O2 and GPx levels. Angiotensin II manipulates the free radical-antioxidant balance in the vasculature by selectively increasing O2 - production and decreasing SOD activity and causes an oxidative stress induced elevation in blood pressure in the Wistar rat., M. M. Govender, A. Nadar., and Obsahuje bibliografii
Monogeneans rely on firm attachment to often flexible and uneven surfaces and are renowned for their effective posterior attachment structures in the form of adhesives, clamps, hamuli and suckers. Polystomatids do not secrete adhesives and do not have clamps. While only some have hamuli, all have suckers in the adult form. Three different types of haptoral suckers have been described based on basic morphology but have never been studied in depth. Using enzyme digestion and light (differential interference contrast), confocal and scanning electron microscopy, we examined representatives and propose four sucker types. Haptoral sucker Type I are symmetrical soft, flexible, cup- to disk-shaped suckers and are found in all polystomes infecting frogs and salamanders. Type II suckers are symmetrical soft, flexible, cup-shaped suckers with a hollow continuous skeletal ring and no other skeletal elements. They are found in species of Nanopolystoma Du Preez, Wilkinson et Huyse, 2008 infecting caecilians. Type III suckers are symmetrical firm, cup-shaped suckers with elaborate skeletal elements that contribute to a secure grip on the host tissue. This type of sucker is found in all polystomes infecting freshwater turtles and the common hippopotamus. Type IV suckers are asymmetrical with an elaborate series of long, thin sclerites with terminal spines or hooks. This type of sucker is only known from Concinnocotyla australensis (Reichenbach-Klinke, 1966) infecting the Australian lungfish. These different sucker types are crucial for the survival of polystomatid flatworms within their respective microhabitats.
Light is critical in determining plant structure and functioning in dune ecosystems, which are characterised by high incident and reflected radiation. Light variations demand great plasticity of the photosynthetic apparatus. This study assessed the phenotypic plasticity of foredune species by analysing their light response and dark recovery curves measured under field conditions. We also addressed the question how coexisting species, structurally distinct, differed in their photochemical efficiency in response to short-term changes in light. Finally, we examined how the varying intensity of stressors operating along a dune gradient affected responses to light. The species differed in light use strategies but showed similar patterns of the dark recovery. Species differences in photochemistry varied seasonally, with species being winter specialists, summer specialist or generalists. Some aspects of their photochemistry varied significantly along the gradient. Unexpectedly, other traits did not vary as predicted. For example, changes in light efficiency of plants along the gradient were not consistent with assumed directional changes in the severity of stressors. The different light use strategies observed in coexisting species did not conform to the prediction that stressors constrain the range of possible functional designs in harsh environments. However, the species followed very similar patterns of post-illumination recovery, which suggests that evolutionary pressures might be acting to maintain similar recovery mechanisms. Our results indicated that dune gradients might be nondirectional, which determines unpredictable patterns of variation in leaf traits along the dune gradient. Seasonal differences in the relative performance may allow species to coexist where otherwise one species would exclude the other., R. Bermúdez, R. Retuerto., and Obsahuje bibliografii
Many species of carabid beetles are important pre- and post-dispersal seed feeders of herbaceous plants. Here we summarise data from dissections, field observations, rearing and "cafeteria" experiments on 55 granivorous and 188 omnivorous species that occur in Italy. We tested the hypothesis that seed feeding carabids are restricted to taxa with pronounced morphological adaptations for manipulating and crushing seeds in both the larval and adult stages. The feeding guilds of carabids were rearranged into the following groups: (i) strict predators with long mandibles and predaceous larvae, often depending also on non-prey food; (ii) omnivorous species with stout mandibles and larvae of a seed-eating morphotype; (iii) granivorous species, feeding only on seeds with larvae sometimes of the scarabeoid c-form type. The seed feeding carabids in the Italian fauna belong to the tribe Zabrini (Amara and Zabrus genera) and to all the Harpalinae (sub)tribes, from Anisodactylini to Ditomina. The time of reproduction seems to be associated with habitat preference; wetland or dry open land, rather than true granivorous versus omnivorous habits, but in stenophagous seed feeders, a phenological coincidence with particular plants is sometimes recorded., Federica Talarico, Anita Giglio, Roberto Pizzolotto, Pietro Brandmayr., and Obsahuje bibliografii
Members of the Philometridae represent the most important group of dracunculoid nematodes parasitizing fishes. In his monograph treating the Dracunculoidea, Moravec (2006) reported a total of 11 genera and 105 species of philometrids parasitizing freshwater, brackish-water and marine fishes. However, during the last six years (2007-2012), an additional 42 new species of Philometridae have been described, representing a 40% increase of the number of nominal species. Most of these species (30) belong to Philometra Costa, 1845, mainly represented by parasites of marine fishes, a few others (8) to Philometroides Yamaguti, 1935, and a single one to each of the following genera: Caranginema Moravec, Montoya-Mendoza et Salgado-Maldonado, 2008, Dentiphilometra Moravec et Wang, 2002, Dentirumai Quiazon et Moravec, 2013* and Spirophilometra Parukhin, 1971. Moreover, three new genera, Afrophilometra Moravec, Charo-Karisa et Jirků, 2009, Caranginema and Dentirumai, were erected. Representatives of seven genera, Afrophilometra, Buckleyella Rasheed, 1963, Caranginema, Dentiphilometra, Dentirumai, Paraphilometroides Moravec et Shaharom-Harrison, 1989 and Rumai Travassos, 1960, were studied using scanning electron microscopy (SEM) for the first time. Thirteen known but poorly described philometrid species were redescribed and, in some species of Caranginema and Philometra, previously unknown conspecific males were discovered and described. The male surface ultrastructure studied by SEM provided new taxonomically important features for species distinction. Gene sequencing was used in several recent studies and advanced our understanding of phylogenetic interrelationships among representatives of seven genera (Afrophilometra, Alinema Rasheed, 1963, Caranginema, Nilonema Khalil, 1960, Philometra, Philometroides and Rumai) and of the extent of the biodiversity of philometrids. New data were obtained on the biology and pathogenicity of several species of Nilonema, Philometra, Philometroides and Rumai. The need to carry out surveys in order to find males and to use SEM and gene sequencing to identify philometrids is emphasized. Appropriate quantitative methods to determine the impact of philometrids in ovarian tissue on host fecundity are recommended. Further detailed studies on philometrids would be significant not only from the theoretical viewpoint, but also because of their practical implications. A list of philometrid nematode species by continents is provided.
River runoff is not only a crucial part of the global water cycle, but it is also an important source for hydropower and an essential element of water balance. This study presents a system-theory-based model for river runoff forecasting taking the Hailiutu River as a case study. The forecasting model, designed for the Hailiutu watershed, was calibrated and verified by long-term precipitation observation data and groundwater exploitation data from the study area. Additionally, frequency analysis, taken as an optimization technique, was applied to improve prediction accuracy. Following model optimization, the overall relative prediction errors are below 10%. The system-theory-based prediction model is applicable to river runoff forecasting, and following optimization by frequency analysis, the prediction error is acceptable.
This article examines the marked decline in Irish social housing’s traditional role as the main source of accommodation for low-income households. We argue that although this policy redirection has become clearly apparent in the context of the Global Financial Crisis; its roots are, in fact, much older. They lie, not in Ireland’s most recent fiscal crisis, but in the last one which occurred between the late 1970s and mid-1980s. Changes made to arrangements for funding social housing during this time effected a long-term contraction in the social housing’s contribution to total housing output which, in turn, precipitated growing reliance on housing allowance subsidised private rented housing to accommodate this group. The post-GFC austerity merely accelerated this long-term trend rather than signalled a new policy direction.
We studied gas exchange of leaves on branches that had been cut and then re-cut under water to assess the utility of measuring gas exchange on leaves of excised canopy branches. There was large variation between species in their ability to photosynthesize following excision. Some species maintained up to 86.5% of intact photosynthetic rate 60 min after excision, whereas other species dropped below 40% of intact photosynthetic rates within 3 min. Three species showed significant reductions in maximum rates of gross photosynthetic rate (PG) on leaves of excised branches relative to intact branches. Excision significantly reduced carboxylation rates (Vcmax) in four species and electron transport (Jmax) in two species. There were also significant increases in compensation irradiance and reductions of day rates of respiration relative to intact measurements. While gas exchange on excised branches can provide useful measures for canopy species, responses of individual species to branch excision need to be taken into account. Measurements on pre-screened species allow a greater understanding of canopy photosynthesis of large trees when canopy access is not an option. and L. S. Santiago, S. S. Mulkey.
The structure of the human microsporidium found by Yachnis and colleagues in two AIDS patients (Am. J. Clin. Pathol. 106: 535-43, 1996) (hereafter referred to as HMY) was investigated by light and transmission electron microscopy and compared with Thelohania apodemi Doby, Jeannes et Raoult, 1963, a microsporidian of small rodents. The fine structure of the HMY was found to be similar to that of Trachipleistophora hominis Hollister, Canning, Weidner, Field, Kench et Marriott, 1996. Characteristic is the presence of a thick layer of electron dense material on the outer lace of the meront plasmalemma, which is maintained during the whole life cycle and which later persists as an electron dense coat on the sporophorous vesicle (SPOV). However, HMY is distinguished from T. hominis during sporogony, as two types of SPOV and spores are formed in HMY. One type of SPOV contains thick-wallcd spores (usually 8 or more in number) with anisofilar polar filaments of 7 + 2 pattem, while the other type contains only two thin-walled spores with a smaller number (3-5) of isofilar polar filament coils. The HMY differs from T. apodemi which also forms SPOV with 8 spores inside, but the spores of which are larger in size and have 9 + 2 polar filament pattern.