The effect of temperature on growth and reproduction of Scytosiphon complanatus (Fucophyceae) from Greenland

Scytosiphon complanatus from Greenland was grown under long-day conditions on a temperature-gradient device with a temperature range from 5.4°C to 31.8°C. Growth was optimal between 16.0°C and 20.9°C. In a four week experimental period at 5.4°C and 7.5°C growth was slow and not measurable. The inoculated germlings died at temperatures between 24.0°C and 27.5°C. Under all temperatures the prostrate systems, knot filaments or ralfsioid thalli, as well as the parenchymatous macrothalli remained sterile during the experimental period. Prolongation of the growth period showed that formation of swarmers was prevented at temperatures above 18.6°C. The geographic distribution is discussed in relation to these results.     

Migration patterns and recapture rates of North-east Arctic and Norwegian coastal cod reared and released under similar conditions

A total of 5000 1-group cod of Northeast Arctic and Norwegian coastal origin were reared under similar conditions, anchor tagged and released at two sites in western Norway. There were significantly more recaptures from the coastal cod. No differences in migration patterns were detected, suggesting that mortality rates were higher in North-east Arctic cod.     

Testing the adaptive hypothesis of Batesian mimicry among hybridizing North American admiral butterflies

Batesian mimicry is characterized by phenotypic convergence between an unpalatable model and a palatable mimic. However, because convergent evolution may arise via alternative evolutionary mechanisms, putative examples of Batesian mimicry must be rigorously tested. Here, we used artificial butterfly facsimiles (N = 4000) to test the prediction that (1) palatable Limenitis lorquini butterflies should experience reduced predation when in sympatry with their putative model, Adelpha californica, (2) protection from predation on L. lorquini should erode outside of the geographical range of the model, and (3) mimetic color pattern traits are more variable in allopatry, consistent with relaxed selection for mimicry. We find support for these predictions, implying that this convergence is the result of selection for Batesian mimicry. Additionally, we conducted mark–recapture studies to examine the effect of mimicry and found that mimics survive significantly longer at sites where the model is abundant. Finally, in contrast to theoretical predictions, we found evidence that the Batesian model (A. californica) is protected from predation outside of its geographic range. We discuss these results considering the ongoing hybridization between L. lorquini and its sister species, L. weidemeyerii, and growing evidence that selection for mimicry predictably leads to a reduction in gene flow between nascent species.     

Effects of citronella oil (Cymbopogon winterianus Jowitt ex Bor) on Spodoptera frugiperda (J. E. Smith) midgut and fat body

The armyworm, Spodoptera frugiperda, is the principal pest of corn in Brazil. Control is achieved primarily by synthetic insecticides, which cause problems for the agro-ecosystem. Alternative methods of control are under investigation and citronella (Cymbopogon winterianus) essential oil appears to be a promising agent. We investigated the effects of citronella oil using histological, histochemical and immunohistochemical methods. The midgut of larvae treated with citronella exhibited altered epithelium including cytoplasmic protrusions, columnar cell extrusion, pyknotic nuclei, and increased periodic acid-Schiff positive granules. Regenerative cells in the epithelium of the midgut increased in number, which facilitated subsequent regeneration of this tissue. After exposure to citronella, trophocytes, the principal cell type of the fat body, possessed enlarged vacuoles and mitotic bodies, and contained reduced amounts of glycogen, lipid, and protein. Citronella oil caused morphological changes of the midgut and reduction of stored resources in the fat body, which may adversely affect insect reproduction and survival.     

Total sleep deprivation does not significantly degrade semantic encoding

ABSTRACT

Sleep deprivation impairs performance on cognitive tasks, but it is unclear which cognitive processes it degrades. We administered a semantic matching task with variable stimulus onset asynchrony (SOA) and both speeded and self-paced trial blocks. The task was administered at the baseline and 24 hours later after 30.8 hours of total sleep deprivation (TSD) or matching well-rested control. After sleep deprivation, the 20% slowest response times (RTs) were significantly increased. However, the semantic encoding time component of the RTs remained at baseline level. Thus, the performance impairment induced by sleep deprivation on this task occurred in cognitive processes downstream of semantic encoding.     

Use of micreosatellite markers for identification of indigenous brown trout in a geographical region heavily influenced by stocked domensticated trout

Based on estimates of genetic differentiation between populations, assignment tests and analysis of isolation by distance, stocked populations of brown trout Salmo trutta of Funen Island, Denmark, had been genetically affected by domesticated trout, whereas the stocking of wild exogenous trout into one of the rivers had little or no impact. At the same time, there were clear indications of remaining indigenous gene pools in the Funen populations. The management implications of these findings are discussed and changes in trout release activity are recommended to avoid further mixing of trout gene pools.     

CD10 expression in non-small cell lung cancer.

CD10 is a cell surface endopeptidase that inactivates various potentially growth stimulatory peptides. In lung cancer cell lines this downregulation has been associated with increased proliferation. Downregulation of CD10 in lung cancer tissue is described, suggesting a potential role in carcinogenesis and a possible use of CD10 as a prognostic marker. We aimed to determine the rate of CD10 expression in our non-small cell lung cancer (NSCLC) collection and to clarify its correlation with clinicopathological parameters and patient survival. 114 NSCLC were analysed immunohistochemically using a monoclonal CD10 antibody (clone NCL-CD10-270) on an NSCLC tissue micro array. The staining was semiquantitatively scored. CD10 expression was observed in 19% of cases, without any significant association with tumour type, -size, -grading, nodal status, clinical stage, and patient survival time. We conclude that a diagnostic use of CD10 immunostaining in NSCLC is unlikely.     

Human mitochondrial uracil-DNA glycosylase preform (UNG1) is processed to two forms one of which is resistant to inhibition by AP sites.

The preform of human mitochondrial uracil-DNA glycosylase (UNG1) contains 35 N-terminal residues required for mitochondrial targeting. We have examined processing of human UNG1 expressed in insect cells and processing in vitro by human mitochondrial extracts . In insect cells we detected a major processed form lacking 29 of the 35 unique N-terminal residues (UNG1Delta29, 31 kDa) and two minor forms lacking the 75 and 77 N-terminal residues, respectively (UNG1Delta75 and UNG1Delta77, 26 kDa). Purified UNG1Delta29 was effectively cleaved in vitro to a fully active 26 kDa form by human mitochondrial extracts. Furthermore, endogenous forms of 31 and 26 kDa were also observed in HeLa mitochondrial extracts. The sequences at the cleavage sites, as identified by peptide sequencing, were compatible with the known specificity of mitochondrial processing peptidase (MPP). However, in vitro cleavage of UNG1Delta29 by mitochondrial extracts did not require divalent cations and was stimulated by EDTA, indicating the involvement of a processing peptidase distinct from MPP at the second site. Interestingly, while UNG1Delta29 generally has the typical properties reported for other uracil-DNA glycosylases, it is not inhibited by apurinic/apyrimidinic sites. Our results indicate that the preform of human mitochondrial uracil-DNA glycosylase is processed to distinctly different forms lacking 29 or 75/77 N-terminal residues, respectively.     

DNA sequence analysis by MALDI mass spectrometry.

Conventional DNA sequencing is based on gel electrophoretic separation of the sequencing products. Gel casting and electrophoresis are the time limiting steps, and the gel separation is occasionally imperfect due to aberrant mobility of certain fragments, leading to erroneous sequence determination. Furthermore, illegitimately terminated products frequently cannot be distinguished from correctly terminated ones, a phenomenon that also obscures data interpretation. In the present work the use of MALDI mass spectrometry for sequencing of DNA amplified from clinical samples is implemented. The unambiguous and fast identification of deletions and substitutions in DNA amplified from heterozygous carriers realistically suggest MALDI mass spectrometry as a future alternative to conventional sequencing procedures for high throughput screening for mutations. Unique features of the method are demonstrated by sequencing a DNA fragment that could not be sequenced conventionally because of gel electrophoretic band compression and the presence of multiple non-specific termination products. Taking advantage of the accurate mass information provided by MALDI mass spectrometry, the sequence was deduced, and the nature of the non-specific termination could be determined. The method described here increases the fidelity in DNA sequencing, is fast, compatible with standard DNA sequencing procedures, and amenable to automation.