SYSTEMATICS OF THE ZYGNEMATACEAE (CHLOROPHYCEAE). III. TRANSEAU COLLECTION OF THE ZYGNEMATACEAE: AN OLD COLLECTION WITH MODERN USES

Edgar Nelson Transeau, botanist-ecologist-phycologist, accumulated a worldwide collection of algal specimens for the compilation of a monograph on the algal family Zygnemataceae, published in 1951. Following his death on January 26, 1960 this Collection remained at The Ohio State University, Columbus until 1978 when it was transferred to the University of Arizona, Tucson. A set of glycerine-preserved specimens on microscope slides is the major item of the Collection with the number of species represented as follows: Spirogyra (138), Mougeotia (52), Zygnema (45), Zygnemopsis (16), Sirogonium (9), Debarya (9), Zygogonium (4), Mougeotiopsis (1) and Entransia (1). All specimens of Pleurodiscus, Sirocladium, Temnogametum and Temnogyra are unidentified. With the Transeau Collection it was demonstrated that an old collection need not be an historical relic, but does have continued usefulness. Potential future use is a powerful justification for maintaining seemingly useless collections whose accumulation often represents the expenditure of untold time, effort and money on the part of many persons and institutions worldwide. Further, as man continues to alter his environment and species are destroyed, collections with long histories become increasingly more valuable. Specimens of the Transeau Collection were subjected to modern techniques, not available earlier, resulting in improved characterization of zygospore-wall structure by scanning electron microscopy and the determination of nuclear DNA by cytofluorometry.     

Heat Resistance of Bacillus Spores at Various Relative Humidities

The thermal resistance characteristics of spores from strains of five different Bacillus species were determined in phosphate buffer and at relative humidities ranging from <0.001 to 100% in a closed-can system. Spores tested in the closed-can system showed a marked increase in heat resistance over those in phosphate buffer, with the greatest increases occurring at relative humidities between 1 and 50%. When estimates of the time to reduce the initial spore concentration 99.99% (F value) at eight different relative humidities were plotted against temperature, three different types of heat resistance profiles were obtained, with maximum resistances at relative humidities of 1, 7, and 30%. When the various strains of spores were heated at the relative humidity of their maximum heat resistance, their relative order of heat resistance was different from that seen in buffer. Spores from the soil isolate were most resistant under these conditions (F_121.1 = 99.5 h).     

The Pleistocene deer hunter of Sardinia

The Pleistocene mammalian fauna of Sardinia isendemic and consists of only a few taxa, indicating island conditions at the time.A sharp faunal break in the Middle Pleistocene separates an older fauna with Nesogoral from a younger one (Middle/Upper Pleistocene) which contains mainly deer (Megaceros cazioti), and ochotonid (Prolagus sardus), a small canid (Cynotherium sardous), and Tyrrhenicola.Commonly paleoecological conditions on islands have led to the development of faunas with dwarfed species, showing a low gear locomotion due to lack of large carnivores. In this aspect the younger Pleistocene fauna of Sardinia is different. A deer with the proportion of mainland species and a small canid were found. This is suggestive of the presence of a large predator. Indeed, together with this fauna a human temporal bone, showing some distinctive characters, was found in Grotta di Corbeddu, Oliena, Sardinia.These findings gave rise to further excavations in the same cave. A paleolithic settlement was discovered and two types of bone artefact could be distinguished. ¹⁴C dating revealed an age of 13590±140 yrs. B.P.These results suggest the development of an endemichuman culture, adapted to the restricted island environment and to the monotonous prey of deer and ochotonids, different from any known culture of that age.     

The Xujiayao 14 Mandibular Ramus and Pleistocene Homo Mandibular Variation

The earlier Late Pleistocene mandibular ramus from Xujiayao (northern China) preserves traits that vary distributionally among western Old World Pleistocene Homo samples and between Early/Middle Pleistocene archaic humans and Late Pleistocene modern humans in eastern Eurasia. Xujiayao 14 presents a lateral mandibular notch crest, an open mandibular foramen, a wide ramus, an asymmetrical mandibular notch, an enlarged superior medial pterygoid tubercle, (probably) a retromolar space, and gonial eversion, as well as an unusual depression in the planum triangulare. The first two traits appear ancestral for Later Pleistocene and recent Homo and are dominant among modern humans. The second two traits largely separate Xujiayao 14 and archaic Homo from modern humans. The next two traits are found in the highest frequency among the Neandertals, although gonial eversion contrasts with Late Pleistocene Neandertals. Xujiayao 14, in the context of Pleistocene and recent Homo samples and the other Xujiayao human remains, therefore provides a morphological mosaic, highlighting regional variation through the Pleistocene.     

Évolution des grands Carnivores au Plio Pléistocène en Afrique et en Europe occidentale

This paper provides an overview of current knowledge of Plio Pleistocene Carnivora from Africa and Europe. In Plio Pleistocene times, many genera extend their ranges in Africa and Eurasia but their evolution are quite distinct in the two continents. In Africa, the modern carnivoran guild of sub saharian Africa originated in the early Pleistocene when took place extinction of archaic species. The north African fossil record is far from complete until the middle Pleistocene. In the middle and late Pleistocene, the modern carnivoran guild is associated with other elements: the simian jackal Canis simensis and two species of ursids Ursus arctos and Ursus deningeri which evolved towards Ursus spelaeus. Western European carnivore faunas show due to migration a constant turn-over of the species. Among felids, Panthera schaubi described by Viret (1954) and attributed to the genus Puma by Hemmer et al. (2004), is morphologically close to the snow leopard Panthera (Uncia) uncia. Canis etruscus is the sister group pf the clade including wolf and coyote and Canis arnensis is close to the African jackals. Ursus deningeri appears in the early Pleistocene together with two arctoid forms Ursus rodei and Ursus dolinensis that may be synonymous to Ursus arctos. The genus Hyaena is present in Europe in the middle and late Pleistocene.     

Role of the Spore Coat Layers in Bacillus subtilis Spore Resistance to Hydrogen Peroxide, Artificial UV-C, UV-B, and Solar UV Radiation

Spores of Bacillus subtilis possess a thick protein coat that consists of an electron-dense outer coat layer and a lamellalike inner coat layer. The spore coat has been shown to confer resistance to lysozyme and other sporicidal substances. In this study, spore coat-defective mutants of B. subtilis (containing the gerE36 and/or cotE::cat mutation) were used to study the relative contributions of spore coat layers to spore resistance to hydrogen peroxide (H₂O₂) and various artificial and solar UV treatments. Spores of strains carrying mutations in gerE and/or cotE were very sensitive to lysozyme and to 5% H₂O₂, as were chemically decoated spores of the wild-type parental strain. Spores of all coat-defective strains were as resistant to 254-nm UV-C radiation as wild-type spores were. Spores possessing the gerE36 mutation were significantly more sensitive to artificial UV-B and solar UV radiation than wild-type spores were. In contrast, spores of strains possessing the cotE::cat mutation were significantly more resistant to all of the UV treatments used than wild-type spores were. Spores of strains carrying both the gerE36 and cotE::cat mutations behaved like gerE36 mutant spores. Our results indicate that the spore coat, particularly the inner coat layer, plays a role in spore resistance to environmentally relevant UV wavelengths.     

First report of a green toad (Bufo viridis sensu lato) in the Early Pleistocene of Spain: Palaeobiogeographical and palaeoecological implications

For the first time unequivocal fossil remains of a green toad (Bufo viridis s.l.) are described in the Iberian Peninsula. The fossils come from the Cueva Victoria site, a late Early Pleistocene (ca. 1.1–1.2 Ma) karstic filling in semi-arid southeastern Spain (Murcia region). By extension, other remains from two other Early Pleistocene Spanish localities, Barranco León D (ca. 1.3 Ma) and Almenara-Casablanca 3 (ca. 1.1 Ma), are cautiously attributed to the group B. viridis. The B. viridis group was previously reported with some uncertainty to the west of its current distribution area in Western Europe (Spain and France) in the Pliocene (Bufo cf. viridis) and less probably in the Early Miocene (Bufo aff. viridis). Since no osteological differences have been established between the recently described extant species of B. viridis s.l. (e.g. Bufo balearicus, Bufo siculus, Bufo boulengeri, B. viridis sensu stricto and Bufo variabilis) no precise palaeobiogeographical relationships can be drawn for the Spanish fossils. However, the occurrence of a third species of bufonid toad during the Pleistocene in the South of the Iberian Peninsula raises some interesting ecological questions in relation to the local disappearance of the green toad, which can be hypothetically linked to the intensification of the Pleistocene glacial/interglacial climate dynamic or to probable competition with another toad, Bufo calamita.     

Role of Germinant Receptors in Caco-2 Cell-Initiated Germination of Bacillus cereus ATCC 14579 Endospores

Spores obtained from Bacillus cereus ATCC 14579 and mutant strains lacking each of seven germinant receptor operons were exposed to differentiated Caco-2 cells and monitored for germination. Spores of the gerI and gerL mutants showed a reduced germination response, pointing to a role for these receptors in Caco-2-induced germination.     

Phylogeographic Patterns of mtDNA Variation Revealed Multiple Glacial Refugia for the Frog Species Feirana taihangnica Endemic to the Qinling Mountains

Diversification patterns and demography of montane species are affected by Pleistocene climate fluctuations. Empirical cases from the Qinling Mountains (QM) region, which is a major biogeographic divider of East Asia, are few. We used DNA sequence data of the complete mitochondrial ND2 gene to detect effects of the Pleistocene glaciations on phylogeographic profiles of a frog species, Feirana taihangnica, which is endemic to the QM. Four distinct lineages consisting of seven sublineages were revealed. The strongest signal of biogeographical structure (F _ct = 0.971, P < 0.01) was found when populations were grouped according to these seven sublineages. One narrow secondary contact zone was detected in the middle QM between the lineage from middle QM and the lineage from eastern QM. Coalescent simulations indicated that this species colonized the QM region by a stepping-stone model. Divergences among lineages had likely been influenced by the uplift of the Tibetan Plateau during the late Miocene-to-late Pleistocene, as well as by the Pleistocene climatic cycles. Coalescent simulations also suggested that F. taihangnica populations have persisted through the Pleistocene glacial periods in multiple refugia across the QM region. Demographic analyses indicated that all lineages, except the lineage in the Funiu Mountains, have been experienced postglacial expansion of population size and distribution range. In conclusion, Pleistocene climate fluctuations and tectonic changes during the late Miocene-late Pleistocene have profoundly influenced the phylogeography and historical demography of F. taihangnica.     

DISTRIBUTION,MORPHOLOGICAL DIVERSITY AND EVIDENCE FOR POLYPLOIDY IN NORTH AMERICAN ZYGNEMATACEAE (CHLOROPHYTA)1

Large-scale collections of Zygnemataceae in the continental United States of America were made between March and August in 1982, 1983, and 1984. Collections were made on a 31000-km transect through 35 states. Zygnemataceae were found at 318 sites was inspected. Temperature average 19°C and p^H averaged 6.1 over all sites. Algal strains in collections were identified to genus, characterized for filament width, chloroplast number, and end wall type, then photographed and isolated into unialgal culture. Spirogyra was the most common genus collected(632 strains), followed in abundance by Zygnema (174 Strains) and Mougeotia (135 strains). These three genera contained 95% of the strains collected and were equally widely distributed. Strains of the three genera frequently occurred together; no genus displayed evidence of habitat specialization among the three habitat types: flowing water, permanent ponds or lakes, and temporary pools. In Spirogyra, strains with plane (flat) end walls were four times more abundant than those with replicate (interlocking) end walls. Spirogyra with plane end walls showed more variation in filament width than Zygnema, Mougeotia, or Spirogyra with replicate end walls. In Spirogyra with plane end walls, filament width was correlted with nuclear DNA content and number of strains found per collection site was twice that of other genera or Spirogyra, with replicate end walls. Spirogyra strains wider than 70 μm were more frequent on the northern part of the transect. It is proposed that polyploidy may be of widespread occurrence in Spirogyra with plane end walls and that associated morphological plasticity may account for the high apparent specied diversity and survival of the genus in a wider variety of microhabitats than occupied by other Zygnemataceae.     

Stephanorhinus hundsheimensis (Mammalia,Rhinocerotidae) from the late early Pleistocene deposits of the Denizli Basin (Anatolia,Turkey)

Pleistocene rhinoceroses are poorly documented in Turkey where they have been reported only from the late early Pleistocene (1.3–1.1 Ma) travertine deposits of the Denizli Basin. In this work, new rhinoceros remains collected from this basin are assigned to a relatively large-sized Stephanorhinus hundsheimensis on the basis of their morphology and morphometry. The first Turkish record of this species is approximately coeval with the first appearance of S. hundsheimensis in Europe, chronologically referred to the late early Pleistocene, ca. 1.2 Ma. During that time, S. etruscus still survived in Iberian Peninsula, central Italy and Dacian Basin. The presence of two successive evolutionary morphs for S. hundsheimensis during the Pleistocene is not confirmed.     

Cougars’ key to survival through the Late Pleistocene extinction: insights from dental microwear texture analysis

Cougars (Puma concolor) are one of only two large cats in North America to have survived the Late Pleistocene extinction (LPE), yet the specific key(s) to their relative success remains unknown. Here, we compare the dental microwear textures of Pleistocene cougars with sympatric felids from the La Brea Tar Pits in southern California that went extinct at the LPE (Panthera atrox and Smilodon fatalis), to clarify potential dietary factors that led to the cougar''s persistence through the LPE. We further assess whether the physical properties of food consumed have changed over time when compared with modern cougars in southern California. Using dental microwear texture analysis (DMTA), which quantifies surface features in three dimensions, we find that modern and Pleistocene cougars are not significantly different from modern African lions in any DMTA attributes, suggesting moderate durophagy (i.e. bone processing). Pleistocene cougars from La Brea have significantly greater complexity and textural fill volume than Panthera atrox (inferred to have primarily consumed flesh from fresh kills) and significantly greater variance in complexity values than S. fatalis. Ultimately, these results suggest that cougars already used or adopted a more generalized dietary strategy during the Pleistocene that may have been key to their subsequent success.     

MOLECULAR PHYLOGENY AND REVISION OF THE GENUS NETRIUM (ZYGNEMATOPHYCEAE,STREPTOPHYTA): NUCLEOTAENIUM GEN. NOV.1

Nuclear‐encoded SSU rDNA, chloroplast LSU rDNA, and rbcL genes were sequenced from 53 strains of conjugating green algae (Zygnematophyceae, Streptophyta) and used to analyze phylogenetic relationships in the traditional order Zygnematales. Analyses of a concatenated data set (5,220 nt) established 12 well‐supported clades in the order; seven of these constituted a superclade, termed “Zygnemataceae.” Together with genera (Zygnema, Mougeotia) traditionally placed in the family Zygnemataceae, the “Zygnemataceae” also included representatives of the genera Cylindrocystis and Mesotaenium, traditionally placed in the family Mesotaeniaceae. A synapomorphic amino acid replacement (codon 192, cysteine replaced by valine) in the LSU of RUBISCO characterized this superclade. The traditional genera Netrium, Cylindrocystis, and Mesotaenium were shown to be para‐ or polyphyletic, highlighting the inadequacy of phenotypic traits used to define these genera. Species of the traditional genus Netrium were resolved as three well‐supported clades each distinct in the number of chloroplasts per cell, their surface morphology (structure and arrangement of lamellae) and the position of the nucleus or nuclear behavior during cell division. Based on molecular phylogenetic analyses and synapomorphic phenotypic traits, the genus Netrium has been revised, and a new genus, Nucleotaenium gen. nov., was established. The genus Planotaenium, also formerly a part of Netrium, was identified as the sister group of the derived Roya/Desmidiales clade and thus occupies a key position in the evolutionary radiation leading to the most species‐rich group of streptophyte green algae.     

Pleistocene marine depositionalenvironments from Mauritius island,Indian Ocean

The Pleistocene elevated marine carbonate complexes on Mauritius island correspond to three types of depositional zones: (1) reef-crest zone, (2) backreef zone, (3) littoral zone.On reef crests, the primary frame-builders are scleractinian corals (Acroporidae, Faviidae, Poritidae) and crustose coralline algae. The secondary builders are encrusting Foraminifers (Homotrematidae) chiefly, Molluscs (Vermetidae), Bryozoans (Cheilostomata) and Serpulids. Associated internal sediments are coarse to fine sand-sized grainstones or packstones and wakestones. In decreasing order of abundance, skeletal elements include fragments of corals, branched and crustose red algae, Pelecypods, Gastropods, benthonic Foraminifera (Amphisteginidae, Peneroplidae, Calcarinidae, Nummulitidae, Alveolinidae and Homotrematidae), Echinoderms and Alcyonarians; the most abundant mud-sized grains are identified as tunicate spicules. Primary marine cements are needle, palisade, micrite and pelletal ones.The backreef zone is characterized by coarse tomedium grainstones, packstones and wakestones. In addition to pellets the most common components are skeletal in nature; they broadly show the same mode of occurrence as the reef-crest unit. Primary cements locally occur in packed fibrous or micrite form.In littoral areas, well-sorted grainstones to poorlysorted mudstones can be described. The distribution of the various categories of biogenic particles is dependent upon the extent of reef tracts; ancient beaches from narrow reefs are characterized by coralgal facies while consolidated muddy banks in large complexes display high amount of molluscan detritus. Primary cementation appears mainly to be the result of the precipitation of fibrous or micrite calcite.The morphology, biological associations andsediments of these Pleistocene limestones are homologous with those of the adjacent modern environments.     

New analysis of the Pleistocene carnivores from Petralona Cave (Macedonia, Greece) based on the Collection of the Thessaloniki Aristotle University

New taxonomic study of the “old collection” of Carnivora from Petralona Cave, associated to the well-known hominid skull, housed in the Geology School of the Thessaloniki Aristotle University since 1960, revealed 11 species (Canis arnensis, Lycaon lycaonoides, Vulpes praeglacialis, Ursus deningeri, U. spelaeus, U. arctos, Pliocrocuta perrieri, Pachycrocuta brevirostris, Crocuta crocuta, Panthera leo spelaea, and Felis silvestris), which are described in detail. The species composition is typical of the eastern part of the European Mediterranean and may be divided into three biostratigraphic assemblages: early Middle Pleistocene, late Middle Pleistocene and Late Pleistocene.     

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Spore formation is a sophisticated mechanism by which some bacteria survive conditions of stress and starvation by producing a multilayered protective capsule enclosing their condensed DNA. Spores are highly resistant to damage by heat, radiation, and commonly employed antibacterial agents. Previously, spores have also been shown to be resistant to photodynamic inactivation using dyes and light that easily destroy the corresponding vegetative bacteria. We have discovered that Bacillus spores are susceptible to photoinactivation by phenothiazinium dyes and low doses of red light. Dimethylmethylene blue, methylene blue, new methylene blue, and toluidine blue O are all effective, while alternative photosensitizers such as Rose Bengal, polylysine chlorin(e6) conjugate, a tricationic porphyrin, and a benzoporphyrin derivative, which easily kill vegetative cells, are ineffective. Spores of Bacillus cereus and B. thuringiensis are most susceptible, B. subtilis and B. atrophaeus are also killed, and B. megaterium is resistant. Photoinactivation is most effective when excess dye is washed from the spores, showing that the dye binds to the spores and that excess dye in solution can quench light delivery. The relatively mild conditions needed for spore killing could have applications for treating wounds contaminated by anthrax spores, for which conventional sporicides would have unacceptable tissue toxicity.     

The geographical and chronological pattern of herpetofaunal Pleistocene extinctions on the Iberian Peninsula

Despite the postulation of the “herpetofaunal stability hypothesis”, which suggests that the herpetofauna underwent relatively few changes during the Pleistocene, the amphibian and squamate faunas of western Europe are known to have progressively diminished during the Pliocene and the beginning of the Pleistocene. Iberian Early Pleistocene sites continue to document the presence of “exotic” herpetofaunal elements that are supposed to have disappeared from the mainland, such as Oriental vipers, agamid lizards, the anguids Pseudopus and Dopasia, and a representative of the green toad group (Bufo viridis sensu lato), as well as possibly gekkonids, a scincid lizard (Lygosominae), the anguid Ragesaurus and blind snake (Scolecophidia). The geographical and temporal pattern of these progressive southward withdrawals and extirpations on the Iberian Peninsula shows that extirpation events occurred in northern Spain at roughly the Olduvai paleomagnetic event and in southern Spain just before the Jaramillo paleomagnetic reversal, thus permitting us to establish a framework that can be used to complement the biochronological zonation of the Iberian Early Pleistocene.     

Selective spore germination on shoots of Homalothecium lutescens,a moss with dwarf males

Spores from three bryophyte species with dwarf males (Homalothecium lutescens, Homalothecium sericeum and Isothecium alopecuroides) were sown on shoots of H. lutescens in vitro. After 10 months, presence and fertility of dwarf plants were scored. Spores of the more distantly related I. alopecuroides were unable to develop into dwarf plants on H. lutescens. Spores of both H. lutescens and H. sericeum developed into dwarf plants. In fact, dwarf plants of H. sericeum were both more abundant and more often fertile than those of H. lutescens. The ability of H. sericeum spores to develop into dwarf males on shoots of H. lutescens suggests a possible pathway for hybridization between the two species. On the other hand, the inability of I. alopecuroides to develop into dwarf males on shoots of H. lutescens suggests that regulation of spore germination and dwarf male development on host shoots is associated with the degree of relatedness between species.     

Light and electron microscope study of Thelohania solenopsae n. sp. (Microsporida: Protozoa) in the red imported fire ant,Solenopsis invicta

A new species of Microsporida, Thelohania solenopsae, is described from the red imported fire ant, Solenopsis invicta. The Thelohania infections are localized in the fat body of workers. Meronts causing infections of progeny are found in the ovaries of queens. Spores occur only in adult ants and only vegetative stages are present in larvae and pupae. Both uninucleate octospores (eight spores within a pansporoblast membrane) and binucleate free spores (spores developing in isolation) are formed.     

Late Pleistocene small mammals from the Wannenköpfe volcanoes (Neuwied Basin, western Germany) with remarks on the stratigraphic range of Arvicola terrestris

Redeposited loess sediments from a Pleistocene crater filling in the Neuwied Basin (western Germany) yielded a small mammal fauna mainly composed of arvicoline rodents. The occurrence of rare faunal elements such as Sorex minutissimus, Sicista subtilis, and a species of Microtus (Terricola) is remarkable. Based on the evolutionary level of Arvicola terrestris, the biostratigraphic age of the fossiliferous horizon is transitional between late Eemian and early Weichselian. This conclusion is partly supported by the generalized ecological requirements of a few dominant rodent species. The fauna contributes to the knowledge of this time period, which is poorly documented in western Germany. A new character of the m1 is proposed for the discrimination of Sicista betulina and S. subtilis. To avoid further confusion in the specific assignment of transitional Arvicola specimens from the late Middle Pleistocene to early Late Pleistocene, we propose the formal taxonomic boundary between chronospecies A. mosbachensis and A. terrestris to be shifted from SDQ value 100 to SDQ value 120.