Physiological strategies contributing to the coexistence of two predatory species of stoneflies: Dinocras cephalotes and Perla bipunctata.

Our study focuses on the oxidative state of two aquatic insects of the order Plecoptera belonging to the family Perlidae, namely Dinocras cephalotes (Curtis, 1827) and Perla bipunctata Pictet, 1833. These species are widely distributed throughout the Western Palearctic region and coexist in the stream where individuals for this study come from. We highlight the physiological strategies of these two different predator species of stoneflies, showing a higher accumulation of lipid reserves in P. bipunctata, higher glucose levels in the body tissues of D. cephalotes and a higher capacity of the antioxidant enzymes in P. bipunctata, what provides it a protection against oxidation of lipids, which are greater in this species. This leads to a similar oxidative state in both species. Based on these results is discussed how two close related species developing a very similar ecological role in the same habitat can achieve a similar fitness with differences in their physiological strategies.

Relationship between brain and liver oxidative state and maximum lifespan potential of different fish species.

The aim of the present study is to determine whether a relationship exists between the maximum lifespan potential (MLSP) of different fish species (Squalius pyrenaicus, Cyprinus carpio, Carassius auratus, Luciobarbus sclateri and Oncorhynchus mykiss) and the oxidative state of brain and liver. For this purpose, the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST) and DT-diaphorase (NAD(P)H:quinone oxidoreductase1) were measured together with the lipid peroxidation degree (malondialdehyde, MDA) in liver and brain tissues of the collected species. Only the brain tissue manifested a higher activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione S-transferase in addition to a negative correlation between the values of MDA and MLSP among the different fish species. Hypotheses are proposed from the analysis of the obtained results that open new areas of research and converge on the importance of the theory of free radicals in the processes that condition the maximum life expectancy of an animal species.

Digestive enzyme activity and trophic behavior in two predator aquatic insects (Plecoptera, Perlidae): a comparative study.

Plecoptera (Perlidae) are among the major macroinvertebrate predators in stream ecosystems and one of the insect families with lower tolerance to environmental alterations, being usually employed as bioindicators of high water ecological quality. The differences in the trophic roles of the coexisting species have been exclusively studied from their gut contents, while no data are available on the comparative digestive capacity. In the present paper, we make a comparative study of the activity of several digestive enzymes, namely proteases (at different pH), amylase, lipase, trypsin and chymotrypsin, in two species of stoneflies, Perla bipunctata and Dinocras cephalotes, which cohabit in the same stream. The study of digestive enzyme activity together with the analysis of gut contents can contribute to a better understanding of the ecology of these aquatic insects and their role in freshwater food webs. Thus, our results show that the two studied predator species inhabiting in the same stream present specializations on their feeding behaviors, facilitating their coexistence, and also differences in their capacity of use the resources. One of the main findings of this study is that D. cephalotes is able to assimilate a wider trophic resource spectrum and this could be one of the reasons why this species has a wider global distribution in all its geographical range.

Digestive enzyme activity of two stonefly species (Insecta, Plecoptera) and their feeding habits.

The digestive enzymes of two stoneflies species, Hemimelaena flaviventris and Isoperla morenica, were studied for the first time. These species are temporary water inhabitants and exhibit great feeding plasticity. Although they are traditionally referred to as predators, a previous study revealed that H. flaviventris incorporates some diatoms into its diet in addition to feeding usually on several prey, and I. morenica (in that study under the name of I. curtata) only feeds on animals occasionally. The enzymatic activities of digestive amylase, lipase, protease, trypsin and chymotrypsin were determined for each species at the same developmental stage. The results show that H. flaviventris has a greater digestive enzymatic pool and higher relative and absolute protease, lipase and trypsin activities than I. morenica. The latter has a relative higher amylase activity. As higher amylase activity is typical of phytophagous species and higher protease activity typical of carnivorous species; these results reveal that H. flaviventris is a more efficient zoophagous species than I. morenica. The ecological implications of these findings, including the higher secondary production of H. flaviventris in its habitat, are discussed.

Dermatofibrosarcoma protuberans with areas of giant cell fibroblastoma in the vulva: a case report.

OBJECTIVE: To review the clinical, morphologic, immunohistochemical, and histogenetic characteristics of dermatofibrosarcoma protuberans with areas of giant cell fibroblastoma and explore current treatment options. METHODS: We describe the case of a 38-year-old patient with a tumor measuring 5.7 cm on the right labium majus of the vulva. Serial sections stained with hematoxylin-eosin were examined and immunohistochemical staining was performed for CD34 and PDGF receptor alpha and beta (PDFGRA and PDGFRB). RESULTS: The histologic study showed spindle-cell proliferation typical of dermatofibrosarcoma protuberans and other areas containing fibrosis and giant cells lining pseudovascular spaces. Both tumor areas expressed CD34, PDGFRA, and PDGFRB. CONCLUSIONS: Only two cases of dermatofibrosarcoma protuberans with areas of giant cell fibroblastoma in the vulva have been reported to date. Both dermatofibrosarcoma protuberans and giant cell fibroblastoma are characterized by the translocation t (17;22) (q22;q13). The fact that PDGFRA and PDGFRB are overexpressed in these tumors opens new treatment options with imatinib. Surgical excision with wide margins or Mohs micrographic surgery continues to be the treatment of choice.

Acute and chronic effects of magnetic microparticles potentially used in lake restoration on Daphnia magna and Chironomus sp.

Magnetic microparticles (MPs) have been recently proposed as a new and promising tool for restoring eutrophicated waters. In this study, we analyzed the acute (immobilization) and chronic effects of iron (Fe) MPs on Daphnia magna and on the benthic macroinvertebrate Chironomus sp. In the chronic toxicity tests the offspring production (male and female) in D. magna and the mortality of larvae and pupae, and adult emergence in Chironomus sp. experiments were used as the endpoints. The concentration of MPs that caused 50% of immobilized individuals (EC50) in the acute toxicity test was much higher in D. magna (0.913g MPs l-1) than in Chironomus sp. (0.445g MPs l-1). The results of chronic toxicity tests in D. magna showed that in presence of dissolved Fe (dFe), parthenogenetic reproduction was significantly affected, while no significant effect on mortality of larvae and pupae and on adult emergence was detected in Chironomus sp. test. Taking into account both that long-term exposure is not likely to occur and the regular dose of MPs potentially used in a restoration plan, we conclude that MPs is a riskless (no toxic effect on planktonic and benthic organisms) and efficient (high P adsorption capacity) tool for lake restoration.

Epidemiological changes in diagnosed coeliac disease in a population of Spanish children.

AIM: To investigate the incidence rate of diagnosed coeliac disease among the paediatric population in the province of Cáceres and the changes over the years. METHODS: The incidence rate of diagnosed coeliac disease between the years 1981 and 1999, age at diagnosis and clinical presentation form were investigated. The study was carried out over two periods: A (1981 to 1990) and B (1991 to 1999). RESULTS: The incidence rate for period A was 6.87/100,000 (CI 95%: 5.26-8.83) and for period B 16.04/100,000 (CI 95%: 12.99-19.59) (p < 0.0001). The relative risk of receiving a diagnosis of coeliac disease during the first four years of life was 2.31% (CI 95%:1.61-3.31) greater in period B than in period A. The mean age at diagnosis was 37.4 +/- 47.4 mo and 43.9 +/- 43.7 mo in A and B, respectively (p = 0.0058). The typical clinical pattern was the most frequent (83.6% in A and 58.3% in B). The mean age of introduction of gluten to the diet was 4.6 +/- 2.0 mo and 6.9 +/- 1.7 mo, for period A and B, respectively (p < 0.0001). CONCLUSION: The incidence rate of coeliac disease has increased during the two periods studied. In recent years, the relative risk of receiving a diagnosis of coeliac disease during the first four years of life has increased. The atypical clinical presentation has also increased, although the typical clinical form is still the most frequent in younger children.