The genus Pnyxiopalpus gen.n. (Diptera: Sciaridae)

Pnyxiopalpus gen.n. (type-species P. raptor sp.n.), Oriental in distribution, includes the following species: P. acanthipes sp.n. (Malay Peninsula), P. aculeatus sp.n. (Borneo), P. adebratti sp.n. (Borneo), P. aphrodite sp.n. (Sumatra), P. dentaneus sp.n. (Sulawesi), P. fossor sp.n. (Borneo), P. fuscinellus sp.n. (Borneo), P. hamatus sp.n. (Borneo), P. latifalx sp.n. (Borneo), P. macrocellus sp.n. (Malay Peninsula), P. microdon sp.n. (Sumatra), P. nepenthophilus sp.n. (Malay Peninsula), P. noona sp.n. (Palawan), P. raptor sp.n. (Borneo), P. reticulatus sp.n. (Malay Peninsula) and P. simplex sp.n. (Borneo). Males and females are keyed and described. Pnyxiopalpus has a number of characters previously unknown in Sciaridae. In contrast to other Sciaridae, interspecific morphological variation is greater for the females compared to the males. Based on a parsimony analysis of sixty-four morphological characters, Pnyxiopalpus is monophyletic, and its sister group appears to be Spathobdella Frey + {[Peyerimhoffia Kieffer + (Faratsiho Paulian + Pnyxia Johannsen)] + [Hyperlasion Schmitz + (Hermapterosciara Mohrig & Mamaev + Parapnyxia Mohrig & Mamaev)]}. According to the most parsimonious solution, the monophyly of Hyperlasion, Lycoriella Frey and Plastosciara Berg in their current sense is questioned. Aptery and one-segmented maxillary palp, usually regarded as important in sciarid classification, show a lot of homoplasy.     

Chromosome counts in the Carex flava complex (Cyperaceae) in Finland

Chromosome numbers from 17 Finnish populations of six taxa in the Carex flava complex were examined. Special attention was given to taxa claimed to be endemic to Fennoscandia. The meiotic counts for C. flava n = 30, C. viridula var. viridula n = 35 and var. pulchella n = 35 are in accordance with previous reports. The counts for C. jemtlandica n = 34, C. bergrothii n = 35, and C. kotilaini n = 34 are new. The hybrid C. flava × kotilaini reveals severely disturbed meiosis with many uni- and multivalents. The results are briefly discussed in relation to morphological data. Carex jemtlandica should evidently be included in C. lepidocarpa. Carex bergrothii and C. kotilaini belong to the polymorphic C. viridula , but the latter probably consitute a specific cytotype.     

Palaeolimnological analyses as information source for large lake biomonitoring

A routinely applicable palaeolimnological sampling and analysis programme for large lake monitoring was developed as part of the Lake Saimaa Biomonitoring Project (1990–1993). The scope of palaeolimnological analyses is to gain background information of the recent past (ca. 0–200 yr) of the lake ecosystem that is being monitored. We analyzed short sediment cores from three contrasting basins of the complex lake Saimaa in eastern Finland (nutrient-poor clearwater Lake Puruvesi; oligotrophic mesohumic Lake Paasivesi, and eutrophied and polluted mesohumic Lake Haukivesi). Each basin shows a unique developmental history under the various forms of human influence on the ecosystem. The following research approaches are evaluated in the study: echosounding, dating (²¹⁰Pb varves, soot stratigraphy), element stratigraphies, biological remains (diatoms, cladocera, chironomids, sedimentary pigments).     

Determinants of helminth aggregation in natural host populations: individual differences or spatial heterogeneity?

We assessed the importance of spatial heterogeneity for the aggregation of helminth populations in the bank vole Clethrionomys glareolus (Arvicolinae) using a previously published method which allows to analyse parasite aggregation at two host population levels, i.e., within and between spatial samples of the host population.
In the main empirical material from Finnish Lapland (Pallasjärvi), all five helminth species were significantly aggregated within study sites, but only three rare species showed significant aggregation among sites. In all helminth species, the total aggregation was primarily (79-98%) determined by aggregation within sites, i.e., between host individuals. Despite the larger spatial scale and more heterogeneous landscape, the comparative material from South Finland (Luhanka) supported the generally high proportion of the total aggregation due to within-site heterogeneity.
Despite the clear interspecific differences in patchiness of helminth populations, the proportion of the total aggregation due to among-site heterogeneity did not vary significantly among helminth species. The results indicate a link between aggregation at two population levels; species that showed strong within-site aggregation were also characterised by pronounced spatial heterogeneity and significant among-site aggregation.     

Cerebral and peripheral blood flow effects of TRH in the rat--a role of vagal nerves

The cardiovascular effects of the IV infusion of TRH were studied in the rat. TRH tended to increase the MAP and markedly increased the CBF(tot) in the control group, in vagotomized animals and in methylatropine-pretreated rats. A marked vasodilation was noted in the pancreas, gastric mucosa, duodenum and cardiac muscle. This effect was turned to vasoconstriction, the heart excluded, in vagotomized animals. Muscarinic blockade attenuated the vasodilating effect of TRH in the duodenum and gastric mucosa. The results indicate that TRH elicits cerebral vasodilation and a partly nonmuscarinic parasympathetically mediated vasodilation in several gastrointestinal organs in parallel with a vasoconstriction which is unmasked by vagotomy.     

Reduced Models of Algae Growth

The simulation of biological systems is often plagued by a high level of noise in the data, as well as by models containing a large number of correlated parameters. As a result, the parameters are poorly identified by the data, and the reliability of the model predictions may be questionable. Bayesian sampling methods provide an avenue for proper statistical analysis in such situations. Nevertheless, simulations should employ models that, on the one hand, are reduced as much as possible, and, on the other hand, are still able to capture the essential features of the phenomena studied. Here, in the case of algae growth modeling, we show how a systematic model reduction can be done. The simplified model is analyzed from both theoretical and statistical points of view.     

Developmental changes in alcohol-dehydrogenase activity in rat and guinea-pig liver

1. Alcohol-dehydrogenase activity is first detectable in the rat foetus on about the eighteenth day of gestation, after which time it increases to about 25% of the adult activity at birth. Adult activity is reached at about 18 days after birth. The ethanol-oxidizing capacity of liver slices from rats correlates well with the increase of the enzyme activity in vitro. 2. In the guinea pig there is a steady linear increase from about 17 days before term to 5 days after birth. Adult activity is reached between the sixth and eighth postnatal day. 3. Some kinetic properties of liver alcohol dehydrogenase are very similar in newborn and adult rats. 4. Administration of ethanol to pregnant rats during the latter half of gestation had no effect on alcohol-dehydrogenase activity in the liver of the newborn offspring. Intraperitoneal injections of ethanol to newborn and young rats had no effect on the alcohol-dehydrogenase activity of the livers. 5. Intraperitoneal injections of hydrocortisone and triamcinolone to newborn and adult non-adrenalectomized rats had no significant effect on the increase of the alcohol-dehydrogenase activity as studied up to 4 days after the injection.     

High stability and low competitive inhibition of thermophilic Thermopolyspora flexuosa GH10 xylanase in biomass-dissolving ionic liquids

Thermophilic Thermopolyspora flexuosa GH10 xylanase (TfXYN10A) was studied in the presence of biomass-dissolving hydrophilic ionic liquids (ILs) [EMIM]OAc, [EMIM]DMP and [DBNH]OAc. The temperature optimum of TfXYN10A with insoluble xylan in the pulp was at 65–70 °C, with solubilised 1 % xylan at 70–75 °C and with 3 % xylan at 75–80 °C. Therefore, the amount of soluble substrate affects the enzyme activity at high temperatures. The experiments with ILs were done with 1 % substrate. TfXYN10A can partially hydrolyse soluble xylan even in the presence of 40 % (v/v) ILs. Although ILs decrease the apparent temperature optimum, a surprising finding was that at the inactivating temperatures (80–90 °C), especially [EMIM]OAc increases the stability of TfXYN10A indicating that the binding of IL molecules strengthens the protein structure. Earlier kinetic studies showed an increased K _m with ILs, indicating that ILs function as competitive inhibitors. TfXYN10A showed low increase of K _m, which was 2-, 3- and 4-fold with 15 % [EMIM]OAc, [DBNH]OAc and [EMIM]DMP, respectively. One reason for the low competitive inhibition could be the high affinity to the substrate (low K _m). Xylanases with low K _m (~1 mg/mL) appear to show higher tolerance to ILs than xylanases with higher K _m (~2 mg/mL). Capillary electrophoresis showed that TfXYN10A hydrolyses xylan to the end-products in 15–35 % ILs practically as completely as without IL, also indicating good binding of the short substrate molecules by TfXYN10A despite of major apparent IL binding sites above the catalytic residues. Substrate binding interactions in the active site appear to explain the high tolerance of TfXYN10A to ILs.