Reduced glutathione promotes callus growth and shoot development in a shoot tip culture of apple root stock M26

Reduced glutathione (GSH) was applied to prevent browning in shoot tip explants of apple (Malus pumila Mill.). Development was compared between shoot tips treated either by (a) dipping into 0.1 mm GSH solution prior to culture (dip treatment), (b) dipping into the GSH solution and transferring to a medium containing 0.1 mm GSH (dip-and-add treatment), or (c) without dipping or culturing with GSH (control). In the dip treatment, 100% of shoot tips developed into normal shoots after 120 days, while the results with the dip-and-add treatment and control were 50 and 40%, respectively. The results show that application of antioxidant GSH in the initial phase of culture promoted the normal development of shoot tips. Received: 10 October 1997 / Revision received: 12 January 1998 / Accepted: 24 January 1998     

Biogeography of ‘tropical Anagallis’ (Myrsinaceae) inferred from nuclear and plastid DNA sequence data

Aim ‘Tropical Anagallis’ corresponds to one of two evolutionary lineages within the genus Anagallis L. Generally, species within this lineage have a limited distribution in (sub‐)tropical regions in Africa or Madagascar. Two species, however, are endemic to South America, and exhibit a trans‐Atlantic disjunction with the rest of the species within the lineage. To investigate this disjunct distribution, as well as other dispersal events, the distribution of extant taxa was used to hypothesize the ancestral area(s) of distribution. Location Africa, Madagascar, Europe and South America. Methods Dispersal–vicariance analysis (DIVA) was used to optimize distribution areas onto parsimony and Bayesian phylogenies based on sequence data from four chloroplast loci and the nuclear internal transcribed spacers (ITS). Results Parsimony analysis gave one most parsimonious tree while Bayesian analysis resulted in a collapsed node due to alternative placements of Anagallis nummularifolia Baker, endemic to Madagascar. Optimization of the present distribution using DIVA, and the most parsimonious tree and six alternative topologies of the Bayesian analysis, show an origin of the lineage in Europe as most likely, although one topology indicates a broader ancestral distribution area. Dispersal to Africa appears to have been a single event, while two parallel dispersal events seem to have resulted in the American as well as Madagascan distributions. Main conclusions The lineage ‘tropical Anagallis’ evolved in Europe and may have been present in the Eocene boreotropical forests, although scarcity of fossils makes assessment of age difficult. Dispersal to South America is proposed to have been via the North Atlantic land bridge, or, more likely, through transport by the North Equatorial Current. Dispersal from Europe to Africa represents a single event, while dispersal to Madagascar from mainland Africa has occurred twice.     

Isolation and Antimacrofouling Activity of Indole and Furoquinoline Alkaloids from ‘Guatambú’ Trees (Aspidosperma australe and Balfourodendron riedelianum)

In this work, the antifouling activity of five alkaloids, isolated from trees of the Atlantic rainforest, was studied. The tested alkaloids were olivacine ( 1 ), uleine ( 2 ) and N‐methyltetrahydroellipticine ( 3 ) from Aspidosperma australe (‘yellow guatambú’) and the furoquinoline alkaloids kokusaginine ( 4 ) and flindersiamine ( 5 ) from Balfourodendron riedelianum (‘white guatambú’). All these compounds can be isolated from their natural sources in high yields in a sustainable way. The five compounds were subjected to laboratory tests (attachment test of the mussel Mytilus edulis platensis) and field trials, by incorporation into soluble matrix paints, and 45 days of exposure of the painted panels in the sea. The results show that compound 3 is a very potent antifoulant, and that compounds 4 and 5 are also very active, while compounds 1 and 2 did not show any significant antifouling activity. These results open the way for the development of environmentally friendly antifouling agents, based on abundant and easy‐to‐purify compounds that can be obtained in a sustainable way.     

Morphological assessment of the Cambrian trilobites Oryctocephalus indicus (Reed 1910) from China and Oryctocephalus ‘reticulatus’ (Lermontova 1940) from Siberia

Oryctocephalus indicus is a widespread trilobite species described from the lower–middle Cambrian (provisional Cambrian Stage 5) of south China, North Korea, India, USA and possibly North Greenland. Principal component analysis (PCA) and thin‐plate splines (TPSs) based on a pooled sample of 359 specimens from four sections in the Guizhou Province, south China, demonstrated that the shape of this species is very constant, and only a small difference is detected in specimens from deeper part of the basin. Most of the variation is taphonomically controlled, and only the specimens from Sanwan Section show a modest natural difference due to a slightly different depositional environment. A comparison between the Chinese specimens and Oryctocephalus ‘reticulatus’ from the Molodo Section, Siberia, has been carried out. PCA and TPS show that O. ‘reticulatus occupies the same morphospace of O. indicus. However, the canonical variates analysis and the analysis of similarities detect small differences between the Siberian and Chinese populations, indicating a minor geographical variation caused by different environmental settings. The ontogenic variation is also described from early meraspids to holaspids. The most substantial changes take place during the first period of the early meraspid development, in which the glabella changes from a bell‐like shape to a cylindrical shape. The ocular ridge changes from poorly defined in early meraspid to well developed in late merapids. The results indicate that O. ‘reticulatus’ is a junior synonym of O. indicus, suggesting that the base O. indicus of Siberia can be correlated with the O. indicus Zone of south China.     

Redescription of the phytosaurs Paleorhinus (‘Francosuchus’) angustifrons and Ebrachosuchus neukami from Germany,with implications for Late Triassic biochronology

Phytosaurs are a diverse and morphologically distinctive clade of superficially crocodile‐like archosauriforms that had a near global distribution during the Late Triassic. Because their remains are among the most abundant vertebrate remains recovered in many Upper Triassic terrestrial formations, phytosaurs are used extensively in long‐range biochronological and biostratigraphic correlations. The biochronologically oldest and earliest branching known phytosaurs include an array of nominal species from the early Late Triassic of the United States, Germany, Poland, Morocco, and India that have been synonymized within the genus Paleorhinus, and subsequently used to define a global ‘Paleorhinus biochron’. However, recent phylogenetic work suggested that the North American species previously referred to Paleorhinus are paraphyletic. Here, we reassess the systematics and anatomy of putative specimens of Paleorhinus from southern Germany. Two well‐preserved basal phytosaur skulls from the Blasensandstein (Carnian) of Bavaria form the holotypes of Francosuchus angustifrons and Ebrachosuchus neukami, both of which were synonymized with Paleorhinus by previous workers. We demonstrate that Francosuchus angustifrons shares unique synapomorphies with specimens referred to Paleorhinus bransoni from the Late Triassic of Texas, and thus refer the species to Paleorhinus. By contrast, the longirostrine Ebrachosuchus is highly distinctive in morphology, and our new cladistic analysis of Phytosauria demonstrates that it represents a valid taxon that is more closely related to Phytosauridae than to Paleorhinus. We provide the first autapomorphy‐based support for a monophyletic but restricted Paleorhinus (supported by a nodal row on the jugal, and low paired ridges on the squamosal) and confirm that previous broader conceptions of Paleorhinus are likely to be paraphyletic. © 2013 The Linnean Society of London     

Interactions between Clostridium beijerinckii and Geobacter metallireducens in co‐culture fermentation with anthrahydroquinone‐2, 6‐disulfonate (AH2QDS) for enhanced biohydrogen production from xylose

To enhance biohydrogen production, Clostridium beijerinckii was co‐cultured with Geobacter metallireducens in the presence of the reduced extracellular electron shuttle anthrahydroquinone‐2, 6‐disulfonate (AH₂QDS). In the co‐culture system, increases of up to 52.3% for maximum cumulative hydrogen production, 38.4% for specific hydrogen production rate, 15.4% for substrate utilization rate, 39.0% for substrate utilization extent, and 34.8% for hydrogen molar yield in co‐culture fermentation were observed compared to a pure culture of C. beijerinckii without AH₂QDS. G. metallireducens grew in the co‐culture system, resulting in a decrease in acetate concentration under co‐culture conditions and a presumed regeneration of AH₂QDS from AQDS. These co‐culture results demonstrate metabolic crosstalk between the fermentative bacterium C. beijerinckii and the respiratory bacterium G. metallireducens and suggest a strategy for industrial biohydrogen production. Biotechnol. Bioeng. 2013; 110: 164–172. © 2012 Wiley Periodicals, Inc.     

Development of an in vitro culture method for cells and tissues from the zebra mussel (<Emphasis Type="Italic">Dreissena polymorpha</Emphasis>)

Despite the successful transfer of mammalian in vitro techniques for use with fish and other vertebrates, little progress has been made in the area of invertebrate tissue culture. This paper describes the development of an in vitro technique for the culture of both cells in suspension and tissue explants from the gill, digestive gland and mantle of the zebra mussel (Dreissena polymorpha) and their successful maintenance in culture for up to 14 days. Cell suspensions from the gills and digestive gland were the most successful technique developed with viability >80% maintained for up to 8 days in culture, suitable for use in short term toxicity tests. Tissue explants from the mantle were also maintained in culture for up to 14 days. This paper describes the challenges involved in the development of a novel in vitro culture technique for aquatic invertebrates.     

Uptake of Organohalide Pollutants,and Release of Partially Dehalogenated Products,by NpRdhA,a ‘Base‐Off’ Cob(II)alamin‐Dependent Reductive Dehalogenase from a Deep Sea Bacterium. A Molecular Dynamics Investigation

This work shows that, during MD aided by external tiny random forces, 3‐bromo‐4‐hydroxybenzoic acid (LHB), the product of reductive dehalogenation of 3,5‐dibromo‐4‐hydroxybenzoic acid (LBB) by the corrin‐based marine enzyme NpRdhA, is expelled along mainly the wide channel that connects the corrin to the external medium. In accordance, unbiased MD showed that LBB migrates relatively rapidly from the external medium to the inside of the channel, finally getting to the corrin active center of NpRdhA. The LBB pose, with bromide head and carboxylate tail nearly equidistant from the corrin Co ion, does not fit the results of previous automatic docking. Either the experimental structure of the NpRdhA‐LBB complex, or a quantum‐mechanical study of LBB at the corrin active site, are therefore urged.     

Structural deviations in the prothoracic tracheal apparatuses of the armoured ground crickets,Acanthoplus speiseri Brancsik., and Enyaliopsis cf. matebelensis Per. (Orthoptera: Tettigoniidae,Hetrodinae) from the ‘typical’ Hetrodinae condition of Zeuner (1936a) and their importance to tettigoniid classification

Prothoracic tracheal apparatuses of Acanthoplus speiseri Brancsik and Enyaliopsis cf. matebelensis Per., are described. The vesicula femoralis for the apparatus of each species differs from the condition considered by Zeuner (1936a) to be typical for the subfamily Hetrodinae to which the two species belong. Acanthoplus speiseri possesses a horn-shaped apparatus, while E. cf. matebelensis bears a trumpet-shaped structure. The horn-shaped prothoracic tracheal apparatus was previously reported to be a specialized structure in the ‘Bradyporoid group’ of Zeuner (1936a). The trumpet-shaped apparatus is reported for the first time in the subfamily. The problems of using the prothoracic tracheal apparatus as a taxonomic character in classifying the tettigoniid subfamilies and the implications of the presence of the atypical prothoracic tracheal apparatuses in the Hetrodinae to the classification of the Tettigoniidae are discussed.