Primary Succession on a Hawaiian Dryland Chronosequence

We used measurements from airborne imaging spectroscopy and LiDAR to quantify the biophysical structure and composition of vegetation on a dryland substrate age gradient in Hawaii. Both vertical stature and species composition changed during primary succession, and reveal a progressive increase in vertical stature on younger substrates followed by a collapse on Pleistocene-aged flows. Tall-stature Metrosideros polymorpha woodlands dominated on the youngest substrates (hundreds of years), and were replaced by the tall-stature endemic tree species Myoporum sandwicense and Sophora chrysophylla on intermediate-aged flows (thousands of years). The oldest substrates (tens of thousands of years) were dominated by the short-stature native shrub Dodonaea viscosa and endemic grass Eragrostis atropioides. We excavated 18 macroscopic charcoal fragments from Pleistocene-aged substrates. Mean radiocarbon age was 2,002 years and ranged from < 200 to 7,730. Genus identities from four fragments indicate that Osteomeles spp. or M. polymorpha once occupied the Pleistocene-aged substrates, but neither of these species is found there today. These findings indicate the existence of fires before humans are known to have occupied the Hawaiian archipelago, and demonstrate that a collapse in vertical stature is prevalent on the oldest substrates. This work contributes to our understanding of prehistoric fires in shaping the trajectory of primary succession in Hawaiian drylands.     

Taxonomic,phylogenetic and ecological diversity of Niphargus (Amphipoda: Crustacea) in the Hölloch cave system (Switzerland)

Groundwater belongs to the spatially most extensive, but least explored freshwater systems. On a global scale, the species richness of several subterranean invertebrate taxa parallels species richness found in surface waters, while on a local scale species richness hardly exceeds 20 species. This results in a high contribution of groundwater ecosystems to regional β- and γ-diversity, and to a smaller degree to α-diversity, and deserves focused attention. In general, more species are to be found in large cave systems. The second largest cave system in Europe is Hölloch in Switzerland. In this paper we revised the taxonomic, phylogenetic and ecological diversity of the amphipod community in the Hölloch cave system. While previous records listed five geographically widespread species of the genus Niphargus for this cave system, we could not confirm the presence of any of those species, but rather found three highly distinct species new to science. In this paper we describe Niphargus styx sp. nov., Niphargus murimali sp. nov., and Niphargus muotae sp. nov., and suggest that previous records from that cave were probably misidentifications. Although amphipod species richness in this cave system seems to be lower than previously thought in terms of absolute numbers, the cave retained its regional and international importance in terms of nature conservation for multiple reasons. First, all newly described species are probably endemic to this cave system. Second, they are phylogenetically distantly related and exhibit moderate to high phylogenetic diversity. Third, the species, as inferred from their functional morphology, are also ecologically highly divergent. Based on geographic distribution of their nearest relatives, we hypothesize that the cave system was most likely independently colonized from North, West and South and that the pre-adapted ancestors occupied different ecological niches within the system.

http://zoobank.org/urn:lsid:zoobank.org:pub:A19309E5-C06B-4844-A4D8-7571F05F25C9     

How to obtain good morphology and antigen detection in the same tissue section?

Most human and animal biopsy samples are routinely embedded in paraffin since this enables the pathologist or researcher to obtain excellent morphology and simplifies storage. Nevertheless, in many cases, the antigen of interest cannot be detected in paraffin section. The alternative available for good immunohistochemistry is preparation of cryosections, which usually provide decent antigen preservation and are frequently used for immunofluorescence. However, cryosections often do not provide efficient morphological details of tissues and cells for pathologic evaluation. In order to obtain good antigen preservation and improve tissue and cell morphology after freezing, we tested three different fixations and freezing methodologies and compared them to routine formaldehyde fixation and paraffin embedding. As a model system, we selected the epithelium of the rat urinary bladder and trachea. On all samples, haematoxylin and eosin staining was performed as well as immunofluorescence with antibodies against tight junction protein ZO-1 and against intermediate filament cytokeratin 7. The best compromise between morphology and immunofluorescence was obtained with “sucrose impregnation prior to freezing” method. Moreover, this procedure is also quicker in comparison to standard paraffin section preparation. To check the clinical relevance of our study, this method was used for human biopsy samples of neoplastic urothelial and bronchial mucosa lesions. Besides good immunofluorescence results, the morphology of these samples was well preserved. We therefore propose that cryosection preparation with sucrose impregnation prior to freezing should be further exploited in other clinical and veterinary applications, since it enables good morphology and antigen preservation.     

Permanent genetic resources added to Molecular Ecology Resources Database 1 February 2011-31 March 2011

This article documents the addition of 111 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acipenser oxyrinchus desotoi, Anopheles nuneztovari sensu lato, Asellus aquaticus, Calopteryx splendens, Calopteryx virgo, Centaurea aspera, Centaurea seridis, Chilina dombeyana, Proctoeces cf. lintoni and Pyrenophora teres f. teres.     

Aspects of the progesterone response in Hortaea werneckii: Steroid detoxification, protein induction and remodelling of the cell wall

Progesterone in sublethal concentrations temporarily inhibits growth of Hortaea werneckii. This study investigates some of the compensatory mechanisms which are activated in the presence of progesterone and are most probably contributing to escape from growth inhibition. These mechanisms lead on the one hand to progesterone biotransformation/detoxification but, on the other, are suggested to increase the resistance of H. werneckii to the steroid. Biotransformation can detoxify progesterone efficiently in the early logarithmic phase, with mostly inducible steroid transforming enzymes, while progesterone biotransformation/detoxification in the late logarithmic and stationary phases of growth is not very efficient. The relative contribution of constitutive steroid transforming enzymes to progesterone biotransformation is increased in these latter phases of growth. In the presence of progesterone, activation of the cell wall integrity pathway is suggested by the overexpression of Pck2 which was detected in the stationary as well as the logarithmic phase of growth of the yeast. Progesterone treated H. werneckii cells were found to be more resistant to cell lysis than mock treated cells, indicating for the first time changes in the yeast cell wall as a result of treatment with progesterone.     

Influence of storage temperature on infectious hematopoietic necrosis virus detection by cell culture isolation and RT-PCR methods

The detection of infectious hematopoietic necrosis virus (IHNV) in infected rainbow trout Oncorhynchus mykiss and in cell culture supernatants stored under different conditions was studied. IHNV-positive fish visceral organ homogenates and cell culture supernatants were incubated at 4 and 25 degrees C. Virus titre was measured by virus isolation on epithelioma papulosum cyprini (EPC) cells and the IHNV RNA was detected by RT-PCR and semi-nested RT-PCR. The influence of repeated freezing and thawing on the virus isolation from organ homogenates and from cell culture supernatants was studied as well. It was possible to isolate the virus from IHNV-positive organ material during the 3 d of incubation at 4 degrees C but, only on the first day of incubation at 25 degrees C. Viral RNA could be amplified during the incubation period of 35 d at 4 degrees C but only during 8 d of incubation at 25 degrees C. In IHNV-infected cell culture supernatant stored at 4 degrees C, it was possible to detect virus for 36 and 16 d in supernatant stored at 25 degrees C. Viral RNA could be followed by using molecular methods during the entire experimental period of 123 d. Each cycle of freezing and thawing of samples resulted in a reduction of IHNV titre in the suspension of visceral organs, while the virus titre in cell culture supernatant remained almost the same following 33 freezing-thawing cycles. The present results show that rapid laboratory processing and storage of potentially virus-containing tissue samples as well as the use of different detection methods are very important for efficient IHNV diagnosis.     

Cell membrane fluidity related to electroporation and resealing

In this paper, we report the results of a systematic attempt to relate the intrinsic plasma membrane fluidity of three different cell lines to their electroporation behaviour, which consists of reversible and irreversible electroporation. Apart from electroporation behaviour of given cell lines the time course required for membrane resealing was determined in order to distinguish the effect of resealing time from the cell’s ability to survive given electric pulse parameters. Reversible, irreversible electroporation and membrane resealing were then related to cell membrane fluidity as determined by electron paramagnetic resonance spectroscopy and computer characterization of membrane domains. We found that cell membrane fluidity does not have significant effect on reversible electroporation although there is a tendency for the voltage required for reversible electroporation to increase with increased membrane fluidity. Cell membrane fluidity, however, may affect irreversible electroporation. Nevertheless, this effect, if present, is masked with different time courses of membrane resealing found for the different cell lines studied. The time course of cell membrane resealing itself could be related to the cell’s ability to survive.     

DNA-based sputum cell image analysis for lung cancer in a clinical setting

OBJECTIVE: To measure cell nuclei characteristics, previously reported to express probability for lung cancer, in subjects with different forms ofpulmonary disease and those without disease. STUDY DESIGN: Sputum and buccal cell samples were obtained from 846 patients without pulmonary disease, with nonmalignant disease, chronic obstructive pulmonary disease, asbestosis and lung cancer, stained for DNA, scanned by cytometer and scored. This was related to specificity and sensitivity for lung cancer. At score 4.5 sensitivity was 53.8% and specificity 70.9%. This score and higher were defined as high scores (HS) and used to compare groups with lung cancer and other pulmonary disease. RESULTS: Among subjects without disease, 21.1% had HS in sputum cells. Among those with nonmalignant pulmonary disease, 31.7% had HS, and among subjects with lung cancer, 53.8% had it. Repeated evaluations showed that about one third of those with HS on the first occasion were normal on repeat sampling. Among subjects without lung cancer, 33.8% of never-smokers had sputum cell HS compared to 22.7.2% among smokers. CONCLUSION: Results demonstrate that the DNA cellular characteristics on cytometry were more frequent among subjects with lung cancer but also among subjects with other pulmonary disease compared to subjects witbout pulmonary disease.     

Hypertrophic cardiomyopathy and sudden cardiac death due to physical exercise in Croatia in a 27-year period

The paper deals with the sudden cardiac death during physical exercise in males in Croatia. The data are a part of a retrospective study dealing with 69 sudden death due to physical activity in men in Croatia during 27 years: from January 1, 1984 to December 31, 2010. Three of them suddenly died during training and two of them died during recreational physical exercise, probably because of malignant ventricular arrhythmia due to hyperthrophic cardiomyopathy. One had an obstructive form of hypertrophic cardiomyopathy with i.v. septum of 40 mm and four had a non-obstructive forms of hyperthrophic cardiomyopathy with left ventricular wall of 18-20-22-25 mm. First athlete was a short trails runner, aged 24, with no any previous physical discomforts, who suddenly collapsed and died during training. The second athlete was a soccer player aged 18, with no any previous physical discomfort, who suddenly collapsed and died during training. The third aged 15, was a school boy, basketball player, with no any previous physical discomfort, who collapsed and died during training. Two aged 25 and 34, were with no physical discomfort during exercise and died suddenly during recreational soccer games. A sudden cardiac death due to physical exercise in young athletes in Croatia suffered of hyperthropic cardiomyopathy reached 0.06/100 000 yearly (p = 0.00000) in 27 years, in teenagers 0.26/100 000 (p = 0.00226), in teenagers suffered of hypertrophic cardiomyopathy reached 0.10/100 000 (p = 0.00000), in all young athletes suffered of other heart diseases reached 0.19/100 000 (p = 0.00005), and in the total male population aged 15 or more, engaged in sports and recreational physical exercise: 0.71/100.0000 (p = 0.00001).