A Revision of the Chinese Athyrium Roth II—Enumeration of the Species (1)

About 300 “species” names of Athyrium from China were published. They are preliminarily treated as 117 species with a number of varieties and hybrids. The complete enumeration will be reported in four parts. The present paper is part one, a key to the species.     

Revision of the Cambrian Agnostina (Trilobita?) from Russia

Cambrian genera and species of Agnostina (?Trilobita) found in Russia are revised. Agnostid trilobite species are used as index taxa in chronostratigraphic subdivisions of the traditional Middle and Upper Cambrian in both regional and global stratigraphic scales. The correlation of the regional and international stratigraphic schemes largely depends on the state of knowledge of the regional agnostid fauna. Therefore, an up-to-date revision of this group based on the Russian collections taking into account their global diversity is very timely. For this study we reexamined the type collections of agnostids, including the holotypes of species described by Russian authors. This paper contains new photographic images of the holotypes housed in Russian museums. The compiled data offered solutions for some difficult taxonomic problems of the families Agnostidae, Ptychagnostidae, Peronopsidae, and some genera of Pseudagnostidae, Diplagnostidae. Apart from listing the diversity, this paper serves as the basis for studying the biogeography and evolution of this interesting arthropod group.     

Revision of the early-middle pleistocene calcareous nannofossil biochronology (1.75–0.85 Ma)

The extant nannofossil biostratigraphic and biochronologic framework for the early-middle Pleistocene time interval has been tested through the micropaleontological analysis of globally distributed high-quality low- to mid-latitude deep-sea successions. The quantitative temporal distribution patterns of relative abundances of selected taxa were reconstructed in critical intervals, and the following biohorizons were defined: first occurrence of medium-sized Gephyrocapsa spp. ($\text{bmG}$); last occurrence of Calcidiscus macintyrei ($\text{tCm}$); first occurrence of large Gephyrocapsa spp. ($\text{blG}$); last occurrence of large Gephyrocapsa spp. ($\text{tlG}$); first occurrence of Reticulofenestra asanoi ($\text{bRa}$); re-entrance of medium-sized Gephyrocapsa spp. ($\text{reemG}$) and last occurrence of Reticulofenestra asanoi ($\text{tRa}$). The detailed patterns of abundance change at these biohorizons were used to generate a detailed biostratigraphy, and the biostratigraphic data were transformed into a precise biochronology by means of correlation to isotope stratigraphies and astronomical timescales. The degree of isochrony or diachrony of the biohorizons was evaluated. Biohorizons $\text{tlG}$ and $\text{tRa}$ are isochronous occurring close to marine isotope stages (MIS) 55 and MIS 22, respectively, and $\text{bmG}$ and $\text{blG}$ are slightly diachronous on the order of 30–40 kyr, whereas biohorizons $\text{tCm}$, $\text{reemG}$ and $\text{bRa}$ are confirmed as diachronous on the order of 100, 80 and 60 kyr, respectively. Some of the events are clearly controlled by environmental conditions, e.g. the last occurrence of R. asanoi, related to significant environmental changes associated with the first large-amplitude glaciation of the late Quaternary, MIS 22.     

Flavonoids ofBignoniaceae from the “cerrado” and their possible taxonomic significance

Flavones and glycosides of flavones and flavonols were obtained from leaves of five species ofBignoniaceae from the cerrado, a savanna ecosystem of Central and Southeast Brazil. A predominance of flavonol glycosides was observed in all samples investigated. Flavones were often found in species of tribeTecomeae and rarely inBignonieae. The species of the former yielded derivatives of 6-hydroxyluteolin. No 6-oxygenated compounds were found in species ofBignonieae. The results point to the flavonoid chemistry evolution ofBignoniaceae following a path of simplification. More complex chemical profiles characterize the more woodyTecomeae rather than the more advancedBignonieae.     

A new species of “sangre de drago” (Croton section Cyclostigma, Euphorbiaceae) from coastal Ecuador

Croton churutensis is described as a new species ofCroton sectionCyclostigma endemic to lowland deciduous forests in coastal Ecuador. Its red latex is used locally in Guayas Province to treat wounds, stomach ulcers, and some skin conditions caused by fungal infections. The new species differs from its closest apparent relative,Croton hibiscifolius, in its arching-pendent inflorescences, short-pedicellate female flowers with quadrifid stigmas, more numerous stamens, laciniate stipules, and lower elevation habitat.     

Mycoflora of the Finnish “sauna” (bath-house)

The investigation concerned the mycoflora of the old, in some cases already discarded, bath houses (sauna) situated in various parts of Finland for the purpose of finding the fungus,Phialophora pedrosoi, which causes chromoblastomycosis in man. The material, 220 specimens, consisting of thin shavings from the wooden floors and platforms, was collected from 78 bath houses. P. pedrosoi was not found in this investigation; the followingPhialophora-species:P. fastigiata, P. lagerbergii, P. lignicola andP. verrucosa were isolated, however.In total 98 various fungus species were isolated, the number of isolates was 1052. Phycomycetes represented 9.2 % of the species and 15.2 % of the isolates, Ascomycetes 4.1 % and 3.4 %, Basidiomycetes 4.1 % and 0.7 % and Fungi imperfecti 82.6 % and 80.7 % respectively of the species and the isolates. The species most frequently isolated from specimens were:Trichoderma viride, Mucor mucedo, Stemphylium consortiale, Rhinocladiella atrovirens, Arthrobotrys superba andPhialophora verrucosa.In all, 13 nematode-destroying fungus species were isolated belonging to the genera:Nematoctonus, Cephalosporium, Harposporium, Dactylaria, Arthrobotrys andDactylella. 60 % of the bath houses were infected by nematodes. Gliodendron gen. nov. with the speciesGliodendron balnicolum sp. nov. is described and illustrated.

---

Zusammenfassung Die Untersuchung betraf die Mykoflora von alten, in manchen Fällen bereits aufgegebenen Badehäusern, die sich in verschiedenen Teilen Finnlands befanden, um den Pilz,Phialophora pedrosoi, den Erreger der Chromoblastomykose, zu finden. Das Material bestand aus 220 Einzelstücken, Spänen von Holzfußböden, die in 78 Badehäusern gesammelt wurden,Phialophora pedrosoi wurde in diesen Untersuchungen nicht gefunden. Die folgendenPhialophora-Arten sind isoliert worden:P. fastigiata, P. lagerbergii, P. lignicola, undP. verrucosa. Insgesamt sind 98 verschiedene Pilzarten isoliert worden. Die Anzahl der Isolierungen war 1052. Phykomyceten stellten 9,2 % von den Arten und 15,2 % der Isolierungen dar: Askomyceten 4,1 % und 3,4 %; Basidiomyceten 4,1 % und 0,7 %; Fungi imperfecti 82,6 % und 80,7 %. Die häufigst isolierten Arten waren:Trichoderma viride, Mucor mucedo, Stemphylium consortiale, Rhinocladiella atrovirens, Arthrobotrys superba undPhialophora verrucosa. Alles in allem wurden 13 Nematoden zerstörende Arten isoliert, die zu den folgenden Gattungen gehörten:Nematoctonus, Cephalosporium, Harposporium, Dactylaria, Arthrobotrys undDactylella. Sechzig Prozent der Badehäuser waren von Nematoden infektiert.Gliodendron gen. nov. ist mit der ArtGliodendron balnicolum, sp. nov. beschrieben und abgebildet worden.

     

Purification and characterization of NAD(P)H quinone reductase from the latex of Hevea brasiliensis Müll.-Arg. (Euphorbiaceae)

NAD(P)H quinone reductase [NAD(P)H-QR] present in the latex of Hevea brasiliensis Müll.-Arg. (Euphorbiaceae) was purified to homogeniety from the B-serum fraction obtained by freeze-thawing of the bottom fraction of ultracentrifuged fresh latex. The purification protocol involved acetone fractionation, heat treatment, ion exchange chromatography and affinity chromatography. The M(r) determined by SDS-PAGE for the protein subunit was 21 kDa, and the molecular mass of the native enzyme estimated by gel filtration was 83 kDa, indicating that the native enzyme is a homotetramer. The enzyme showed pH stability over a range of 6 to at least 10 (with an optimum at pH 8) and thermal stability up to 80 degrees C. High NAD(P)H-QR activity (70%) was still retained after 10 h of preincubation at 80 degrees C. A comparable substrate specificity for this enzyme was observed among menadione, p-benzoquinone, juglone, and plumbagin, with only duroquinone generating a lower activity. Positive correlations between latex NAD(P)H-QR activity and rubber yield per tapping [fresh latex (r=0.89, P<0.01), dry rubber (r=0.81, P<0.01)] together with flow time (r=0.85, P<0.01) indicated that enzyme activity could possibly be used as a marker to predict the yield potential of selected clones.     

Revision of the lower Viséan (MFZ11) calcareous algae and archaediscoid foraminifers of the Sari area (central Alborz,Iran)

The microfloral and microfaunal assemblages of the MFZ11 foraminiferal biozone (late early SomervilleViséan; formerly V2a) are well developed in the Kiyasar section of the Sari area (central Alborz; northern Iran). Regionally, this biozone MFZ11 may be subdivided into three subzones. The lower subzone, MFZ11A, is characterized by the appearances of the algae Koninckopora tenuiramosa, coeloporellacean indet. Fourstonella fusiformis, and Nanopora anglica and, among the foraminifers, by the occurrence of Ammarchaediscus bozorgniai and the disappearance of Eoparastaffella simplex; the absence of Uralodiscus rotundus, U. spp., and primitive Glomodiscus spp. in this subzone is noticeable. The next subzone, MFZ11B1, is well characterized by the appearance of Glomodiscus spp. (G. oblongus and G. cf. miloni) and the local range zone of Pararchaediscus, a genus emended herein and interpreted as a junior synonym of Archaediscus at the involutus stage and Propermodiscus; only a few characteristic issinellacean and palaeoberesellacean algae are present in this subzone. Then, the last subzone, MFZ11B2, is characterized by Hemiarchaediscus (emended herein) and Glomodiscus miloni; the upper part of this latter subzone is only marked by the apparent absence of the archaediscids and the presence of two incertae sedis algae: Crassikamaena scabrosa and Epistacheoides bozorgniai nov. sp. These assemblages indicate that at that time, Alborz remained located on the Perigondwanan southern border of the Palaeotethys, and was probably connected with the Urals as well as the northwestern branch the Palaeotethys, from Belgium to the Donets Basin.     

Revision of the lower Aptian (Lower Cretaceous) ammonite species Cheloniceras cornuelianum (d’Orbigny, 1841)

The aim of the present work is to determine the morphological characteristics of the lower Aptian (lower Cretaceous) ammonite species Cheloniceras cornuelianum (d’Orbigny, 1841) (Douvilleiceratinae, Douvilleiceratidae) on the basis of 32 specimens from the Paris Basin (France), including the lectotype of the species and 23 topotype specimens. It is generally admitted that this species occurs in the Deshayesites forbesi-Dufrenoyia furcata zones interval (lower Aptian). Our study has lead to several unexpected results. First, the study sample of C. cornuelianum is very probably younger and has more primitive traits than expected: it is probably dated around the limit between the Deshayesites forbesi and Deshayesites deshayesi zones and is morphologically close to the earlier genus Procheloniceras Spath, 1923. Secondly, the lectotype is an extreme specimen with much derived traits compared to its original population. It constitutes an example of type-specimen not morphologically representative of its original population, responsible of a risk of misinterpretation of the species. Finally, the intraspecific variability and the proportion of asymmetric specimens of the study sample of C. cornuelianum are very important but there is no evidence of sexual dimorphism.     

Pathophysiology of the Ischemic Penumbra—Revision of a Concept

1. The original concept of the ischemic penumbra surrounding a focus of dense cerebral ischemia is based on electrophysiological observations. In the cortex of baboons following middle cerebral artery occlusion, complete failure of the cortical evoked potential was observed at a cerebral blood flow (CBF) threshold level of approx. 0.15 ml/g/min—a level at which extracellular potassium ion activity was only mildly elevated. With a greater CBF decrement to the range of 0.06–0.10 ml/g/min, massive increases in extracellular potassium occurred and were associated with complete tissue infarction. Thus, the ischemic penumbra has been conceptualized as a region in which CBF reduction has exceeded the threshold for failure of electrical function but not that for membrane failure.2. Recent studies demonstrate that the penumbra as defined classically by the flow thresholds does not survive prolonged periods of ischemia. The correlation of CBF autoradiograms with diffusion-weighted MR images and the regional distribution of cerebral metabolites reveals that the ischemic core region enlarges when adjacent, formerly penumbral, areas undergo irreversible deterioration during the initial hours of vascular occlusion. At the same time, the residual penumbra becomes restricted to the periphery of the ischemic territory, and its fate may depend critically upon early therapeutic intervention.3. In the border zone of brain infarcts, marked uncoupling of local CBF and glucose utilization is consistently observed. The correlation with electrophysiological measurements shows that metabolism-flow uncoupling is associated with sustained deflections of the direct current (DC) potential resembling transient depolarizations. Such penumbral cell depolarizations, which are associated with an increased metabolic workload, induce episodes of tissue hypoxia due to the constrained collateral flow, stimulate anaerobic glycolysis leading to lactacidosis, suppress protein synthesis, and, finally, compromise energy metabolism. The frequency of their occurrence correlates with the final volume of ischemic injury. Therefore, penumbral depolarizations are regarded as a key event in the pathogenesis of ischemic brain injury. Periinfarct DC deflections can be suppressed by NMDA and non-NMDA antagonists, resulting in a significant reduction of infarct size.4. The histopathological sequelae within the penumbra consist of various degrees of scattered neuronal injury, also termed incomplete infarction. The reduction of neuronal density at the infarct border is a flow- and time-dependent event which is accompanied by an early response of glial cells. As early as 3 hr after vascular occlusion a generalized microglial activation can be detected throughout the ipsilateral cortex. Astrocytic activation is observed in the intact parts of the ischemic hemisphere from 6 hr postocclusion onward. Thus, the penumbra is a spatially dynamic brain region of limited viability which is characterized by complex pathophysiological changes involving neuronal function as well as glial activation in response to local ischemic injury.     

On the heterogeneity of the slow reassociating (“unique”) DNA

Summary The slow reassociating fraction of mouse DNA (unique DNA), when allowed to reassociate in 0.14 m sodium phosphate buffer at 50 °C showed a biphasic melting curve with a transition at 78–80 °C. On the basis of this feature, the slow reassociating DNA was separated preparatively into two fractions: unique DNA I and II. Their duplexes showed differences with respect to thermal stability, S1 nuclease resistance and rate of reassociation. About one third of the sequences in each fraction were fraction-specific. The conclusion was drawn that for unique DNA I these should be the low repetitive or single copy related sequences (multigene families) and for unique DNA II—the unrelated single copy sequences or recent families of low repetitive not yet diverged sequences.     

Dated Phylogenies of the Sister Genera Macaranga and Mallotus (Euphorbiaceae): Congruence in Historical Biogeographic Patterns?

Molecular phylogenies and estimates of divergence times within the sister genera Macaranga and Mallotus were estimated using Bayesian relaxed clock analyses of two generic data sets, one per genus. Both data sets were based on different molecular markers and largely different samples. Per genus three calibration points were utilised. The basal calibration point (crown node of all taxa used) was taken from literature and used for both taxa. The other three calibrations were based on fossils of which two were used per genus. We compared patterns of dispersal and diversification in Macaranga and Mallotus using ancestral area reconstruction in RASP (S-DIVA option) and contrasted our results with biogeographical and geological records to assess accuracy of inferred age estimates. A check of the fossil calibration point showed that the Japanese fossil, used for dating the divergence of Mallotus, probably had to be attached to a lower node, the stem node of all pioneer species, but even then the divergence time was still younger than the estimated age of the fossil. The African (only used in the Macaranga data set) and New Zealand fossils (used for both genera) seemed reliably placed. Our results are in line with existing geological data and the presence of stepping stones that provided dispersal pathways from Borneo to New Guinea-Australia, from Borneo to mainland Asia and additionally at least once to Africa and Madagascar via land and back to India via Indian Ocean island chains. The two genera show congruence in dispersal patterns, which corroborate divergence time estimates, although the overall mode and tempo of dispersal and diversification differ significantly as shown by distribution patterns of extant species.