Feulgen-positive staining of the cell nuclei in fossilized leaf and fruit tissues of the Lower Eocene Myrtaceae

The Feulgen reaction and the staining of preparations with two DNA-specific fluorochromes, Hoechst 33258 and 4',6-diamidino-2-fenilindol (DAPI), were used to study the preservation of DNA in the fossilized leaf and fruit tissues of the Lower Eocene Myrtaceae, Paramyrtacicarpus plurilocularis and Paramyrtaciphyllum agapovii collected in Yakutia (Siberia, Russia). It was shown that chromatin structures of the fossilized plants form stable red-purple complexes with the Schiff's fuchsin sulphuric acid reagent in situ . This coloration is specific for DNA, in particular, for the deoxyribose residues. It means that the cell nuclei of these 53–55 Myr old plants preserve a part of the deoxyribose backbone of DNA molecules. On the other hand, there was no, or only a very weak, staining of the cell nucleus with fluorochromes DAPI or Hoechst 33258, which specifically bind to the double-stranded DNA and do not bind to either the single-stranded DNA or RNA molecules. The stainability of fossil plant cell preparations with alcian blue shows that there are also polysaccharides containing carboxyl groups in the cell walls of fossilized leaf and fruit tissues of the Lower Eocene Myrtaceae.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 315–321.     

Functional analysis of NLP genes from Botrytis elliptica

We functionally analysed two Nep1-like protein (NLP) genes from Botrytis elliptica (a specialized pathogen of lily), encoding proteins homologous to the necrosis and ethylene-inducing protein (NEP1) from Fusarium oxysporum. Single gene replacement mutants were made for BeNEP1 and BeNEP2 , providing the first example of transformation and successful targeted mutagenesis in this fungus. The virulence of both mutants on lily leaves was not affected. BeNEP1 and BeNEP2 were individually expressed in the yeast Pichia pastoris , and the necrosis-inducing activity was tested by infiltration of both proteins into leaves of several monocots and eudicots. Necrotic symptoms developed on the eudicots tobacco, Nicotiana benthamiana and Arabidopsis thaliana , and cell death was induced in tomato cell suspensions. No necrotic symptoms developed on leaves of the monocots rice, maize and lily. These results support the hypothesis that the necrosis-inducing activity of NLPs is limited to eudicots. We conclude that NLPs are not essential virulence factors and they do not function as host-selective toxins for B. elliptica .     

Nitrogen Economy of Post-fire Stands of Shrub Legumes in Jarrah (Eucalyptus marginata Donn ex Sm.) Forest of S.W. Australia

Hansen, A. P., Pate, J. S., Hansen, A. and Bell, D. T. 1987.Nitrogen economy of post-fire stands of shrub legumes in jarrah(Eucalyptus marginata Donn ex Sm.) forest of S.W. Australia.—J.exp. Bot. 38: 26–41. Growth, demography and N economy of 1–6-year-old standsof Acacia pulchella, A. alata, A. extensa and Bossiaea aquifoliumwere examined using population sampling to assess annual incrementsof N as living biomass, and returns of N as litter, seed anddead plants. Dependence on nitrogen fixation was assessed fromseasonal profiles of acetylene reduction, employing data fromprevious calibrations to convert C₂H₂ reduced to N₂ fixed. After2 years of slow growth and minimal reproduction all speciesgrew rapidly to achieve maximum or near maximum size and seedproduction. Intense self-thinning of stands occurred in thesecond and third years, especially in the highly dense standsof the smallest species, A. alata. Annual turnover in standsranged from 0?3 to 127 kg N ha^–1 year^–1, dependingon species current age and density of a stand. Returns of Nas litter and shed seed comprised small proportions of the annualbudgets, but returns due to plant death equalled or exceededincrements of living biomass in years when stands were thinningrapidly. Proportional dependencies of the species on fixed N₂were relatively high (13–61%) in first year seedlings,and then declined markedly to 1?1–3?4percnt; in the second,0?3–1?6% in the third, and, with one exception, to wellbelow 1% in the fourth and sixth year stands. Mean annual ratesof N₂ fixation over the 6-year post-fire period were 1?6 kgN ha^–1 year^–1 for A. alata, 0–49 for A. pulchella,0?19 for B. aquifolium and 0-10 for A. extensa Key words: Shrub legumes, post-fire N economy     

The Recent species of Adeonella (Bryozoa: Cheilostomata) including descriptions of fifteen new species

The genus Adeonella Busk (1884) comprises 41 species, 15 of which are considered to be new to science. Adeonella lichenoides (Lamarck) is regarded as the senior synonym of A. platalea (Busk) (= A. polymorpha Busk), the type species of the genus. Adeonella is distributed throughout the Indo-West Pacific realm, the Mediterranean, and the South Atlantic Ocean. Its highest diversity is found off the east coasts of southern Africa. Thirty-one species (15 new to science) are described and illustrated, morphology and geographical distribution are discussed and a key is provided to all recognized species.     

A new family of cheilostome Bryozoa endemic to Antarctica

Five species of erect cheilostome Bryozoa from Antarctica are considered to constitute a new family, Eminooeciidae. A new genus Eminooecia is introduced for Hippadenella carsonae Rogick. Two new species are described in the genus Ioschizoporella Rogick.     

Hearing in tiger beetles (Cicindelidae)

ABSTRACT. Tympanic hearing organs (ears) are reported for several tiger beetle (Cicindelidae) species. The paired ears are positioned bilaterally on the first abdominal tergum and consist of cavities covered by thin tympana. When the beetle is not flying the elytra covers its ears and reduces their sensitivity to sound. However, when the beetle is flying, its exposed ears are capable of detecting ultrasonic pulses. Under a microscope, beetles with their elytra artificially raised contract their abdomens in response to ultrasound. Ultrasonic emissions directed toward flying beetles induce them immediately to fly downward and land, a response which probably aids escape from predators, particularly echolocating bats. Other possible uses for the ears are the avoidance of diurnal insect predators and intraspecific communication.     

Ateleaspis tessellata Traquair, a non-cornuate cephalaspid from the Upper Silurian of Scotland

Ateleaspis tessellata Traquair, a non-cornuate cephalaspid from the U. Silurian of Scotland, is re-examined on the evidence of new material from the original localities. The species is found to be less 'primitive' than was previously thought in that the pectoral fins are separated from the trunk posteriorly by a distinct sinus and the two dorsal fins are developed essentially as in Aceraspis robustus Kiaer. The ventral visceral exoskeleton is described for the first time. Ateleaspis and Aceraspis are so close in so many respects that retention of separate genera is unnecessary; Aceraspis must be suppressed since Ateleaspis has priority. Revised diagnoses of the genus Ateleaspis and its two species, A. tessellata Traquair and A. robustus (Kiaer), are given and their relationships with other non-cornuate cephalaspids discussed.     

Heart and liver as developmental bottlenecks of mammal design: evidence from cell polyploidization

A new concept in physiological evolution in mammals is proposed based on the data of cell and developmental biology. The levels of mammal cardiomyocyte and hepatocyte ploidy were analysed with regards to body mass, growth rate in different periods of ontogenesis, and maximal functional potential of the heart and liver in the adult state. For both organs, cell ploidy and functional potential of the organ correlated inversely. Polyploid cells were shown to have a lower amount of protein per genome and a lower ratio of mitochondrial internal membrane to tissue‐specific cellular machinery (i.e. a lower energy supply) compared with diploid cells. Both cell ploidy and functional potential of the organ correlated with the animal growth rate that controls the organ functional load, but only if measured during the period of ontogenesis when polyploidization of the particular organ proceeds. However, correlation was in opposite directions: negative in the heart and positive in the liver. This is because these organs provide predominantly for the antagonistic tasks that they perform during ontogenesis. The liver provides a gain in body mass, whereas the heart maintains locomotor activity. The balance between these tasks depends on the growth rate constrained by the degree of precocity of development. During ontogenesis, an organ that works intensively in the adult state is subjected to a low workload and is furnished plentifully by resources. On the contrary, an organ with a low functional potential in the adult state starts to work intensively just after birth and experiences a shortage of resources during growth. Our data indicate that somatic polyploidization occurs as a result of tension between growth and function caused by the limitation of resources. The highest levels of mammal cell ploidy occur in the heart and the liver, although in different species which are positioned on the opposite ends of the growth rate range. Thus, the heart and the liver seem to be developmental bottlenecks of mammal design, determining the limits of metabolic capacity of adult animals. Compared with other mammals, the human has a very slow growth rate and a very high ploidy of cardiomyocytes (thus confirming the revealed regularity). This helps explain the well‐known fact that cardiovascular failure is the number one cause of human mortality. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 175–186.