A morphometric and molecular study in Tortula subulata complex (Pottiaceae, Bryophyta)

Specimens belonging to Tortula subulata complex ( T. inermis , T. mucronifolia and T. subulata ) were analysed using a combination of morphometric methods based on quantitative characters [principal component analysis (PCA), discriminant analysis (DA); 76 samples)] and molecular methods (ITS1 – 5.8S rRNA gene and ITS2; 47 samples) to assess patterns of morphological and molecular differentiation within this complex of taxa. The study shows that four species can be recognized: T. mucronifolia , T. subulata , T. inermis and T. subulata var. angustata with bistratose border, which is elevated to the species rank as T. schimperi nom. nov. The most valuable quantitative characters for identification of these species are the strata number of the marginal laminal cells, the ratio of middle marginal laminal cell width/middle marginal laminal cell length, basal membrane of peristome length, middle laminal cell width and papillae number on the middle laminal cells. The internal transcribed spacer (ITS) data suggest that this group of taxa is not monophyletic, T. mucronifolia being close to Protobryum bryoides (= Tortula protobryoides ). The remaining species seem to be a monophyletic group, T. schimperi being the sister group of the clade composed by T. inermis and T. subulata . T. subulata is considered to be of high morphological variability, for which ITS sequences did not resolve the internal relationships.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 333–350.     

Function of defensive volatiles in pedunculate oak (Quercus robur) is tricked by the moth Tortrix viridana

The indirect defences of plants are comprised of herbivore‐induced plant volatiles (HIPVs) that among other things attract the natural enemies of insects. However, the actual extent of the benefits of HIPV emissions in complex co‐evolved plant‐herbivore systems is only poorly understood. The observation that a few Quercus robur L. trees constantly tolerated (T‐oaks) infestation by a major pest of oaks (Tortrix viridana L.), compared with heavily defoliated trees (susceptible: S‐oaks), lead us to a combined biochemical and behavioural study. We used these evidently different phenotypes to analyse whether the resistance of T‐oaks to the herbivore was dependent on the amount and scent of HIPVs and/or differences in non‐volatile polyphenolic leaf constituents (as quercetin‐, kaempferol‐ and flavonol glycosides). In addition to non‐volatile metabolic differences, typically defensive HIPV emissions differed between S‐oaks and T‐oaks. Female moths were attracted by the blend of HIPVs from S‐oaks, showing significantly higher amounts of (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT) and (E)‐β‐ocimene and avoid T‐oaks with relative high fraction of the sesquiterpenes α‐farnesene and germacrene D. Hence, the strategy of T‐oaks exhibiting directly herbivore‐repellent HIPV emissions instead of high emissions of predator‐attracting HIPVs of the S‐oaks appears to be the better mechanism for avoiding defoliation.     

Continuous monitoring of phytoplankton dynamics in Lake Balaton (Hungary) using on-line delayed fluorescence excitation spectroscopy

1. This study introduces delayed fluorescence (DF) excitation spectroscopy as an on‐line tool for in situ monitoring of the composition and biomass of various colour classes of phytoplankton when they are photosynthetically active (cyanobacteria, chlorophytes, chromophytes and cryptophytes). The DF data are validated by comparison with those from conventional methods (weekly microscopic counts and the measurement of chlorophyll concentration). 2. The composition of phytoplankton as assessed by DF agreed reasonably well with the results from microscopic counts, particularly when differences in chlorophyll‐specific DF integrals of the various colour classes were taken into account. 3. Integrals of DF spectra were converted into concentration of chlorophyll a using empirical factors derived from field data. The value of the conversion factor was nearly twice as high when the relative abundance of cyanobacteria was low (<15%) than when it was high. The converted DF‐chl time series agreed well with chlorophyll measurements particularly when blooms were developing. As the DF method is inherently free of the interference caused by pigment degradation products, the discrepancy between the two data sets increased during the collapse of blooms and when sediment resuspension was intense. 4. Fourier spectrum analysis of the time series of DF‐chl indicated that samples must be taken, at a minimum, every 2–3 days to capture the dynamics of phytoplankton. As a consequence, the dynamics of various algal blooms, including their timing, duration and net growth rate, could be estimated with greater confidence than by using conventional methods alone. 5. On‐line DF spectroscopy is an advanced technique for monitoring daily the biomass and composition of the photosynthetically active phytoplankton in aquatic environments, including turbid shallow lakes. At present, the detection limit is around 1 mg DF‐chl a m^?3 in terms of total biomass but confidence in estimates of phytoplankton composition declines sharply below about 5 mg chl a m^?3. 6. On‐line DF spectroscopy represents a promising approach for monitoring phytoplankton. It will be useful in water management where it can act as an early‐warning system of declines in water quality. In basic ecological research it can supplement manual methods. While default calibration spectra may be acceptable for routine monitoring, we suggest a careful individual calibration of the DF spectrometer for basic research. The statistical methods developed here help to assess the adequacy of various calibration sets.     

Ontogenetically stable dimorphism in a lacertid lizard (Acanthodactylus boskianus) with tests of methodology and comments on life-history

Recent arguments in the literature prompted us to compare methods for assessing sexual dimorphism in body proportions of lacertid lizards, using Acanthodactylus boskianus . Although expressing body-part measurements as proportional to head length was the most effective method, we recommend using trunk length for the baseline as a general method for lizards. We also argue that, when aiming to assess sexual dimorphism in body proportions of lizards, if the context is ecological, all available adults should be included. However, for morphology and taxonomy, small sub-samples of the largest individuals that maximally express their genetic morphological potential should be used. In A. boskianus , the sexual dimorphism of mensural characters in adults was typical: males were larger, with relatively larger head and appendages. However, the ontogeny of this dimorphism was unusual in that the differences existed already in youth and thereafter persisted isometrically. The sexual dimorphism of meristic characters was male-biased in numbers of femoral pores and of caudal vertebrae, and female-biased in numbers of ventral plates along the trunk and of precaudal vertebrae. Size dimorphism may conceivably play a role in sex recognition because two potential visual cues (i.e. size dimorphism and dichromatism) appear to complement each other.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society 2009, 97 , 275–288.     

Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans

We compared 42 phylogenetically conserved proteins from four marine sponges [Porifera] with almost the complete set of Caenorhabditis elegans proteins and all known proteins from humans. The majority of the sponge proteins arc significantly more similar to human than to C. elegans orthologucs/homologues. This finding reflects the accelerated evolutionary rate in the C. elegans lineage, since sponges split off first from the common ancestor of all multicellular animals. Furthermore, three sponge/human proteins were not found in C. elegans: (2–5)A synthetase, DNA repair helicase and lens βγ-crystallin. Sponges arc the source of the most ancient proteins already present in the common ancestor of all multicellular organisms. Some of these proteins were lost later during the evolution of individual animal lineages. These 'found/lost' proteins may serve as molecular markers for an improved systematics of Metazoa. In addition, phylogenetically conserved sponge proteins can be very helpful for the evaluation of differences in evolutionary rates in different animal lineages. We therefore propose sponges as the reference animals in molecular evolutionary studies of Metazoa.     

Indirect Immunofluorescence Microscopy of Microtubular Structures in Male Germ Cells of Wildtype and l(3)pl (lethal-polyploid) Drosophila hydei

Tubulin-containing structures of the male germ cells of Drosophila hydei crossreact in indirect immu-nofluorescence microscopy with antibody directed against homogeneous porcine brain tubulin. There is no detectable difference in reactivity between germ cells of wildtype flies and the mutant l(3)pl (lethal-polyploid) which is characterized by microtubular abnormalities. However, the technique of indirect immunofluorescence microscopy allows the direct visualization of several abnormalities in the arrangement of the microtubular system of the mutant, particularly in the axonemal complex.     

Temperature-dependent changes in circadian patterns of cricket premating behaviour

ABSTRACT. Male-calling and female-walking in Teleogryllus commodus (Walker) is mainly performed during the night (in LD 12:12 at constant temperature). Cold nights of 1–7°C switched both activities from night to daytime. After cold exposure it took several transient cycles until the original phase angle difference to lights-out was re-established. The involvement of a circadian clock in these processes was revealed by observing the free-running rhythm in constant light after a cold night. The rhythm was delayed, evidently due to the resetting of the biological clock by the cold exposure. This temporal alteration of premating behaviour in males and females is discussed in relation to intraspecific consequences, its adaptive value in natural conditions, and with respect to the potential parallel effects in parasites and predators.     

Characteristics of Zinc Uptake by Barley Roots

The linear uptake of zinc by excised barley roots (Hordeum distichon L.) in the time range from 20–120 min is not continued over periods of 20–28 h. In concentration dependent uptake experiments with intact barley roots three phases in the range up to 1.38 mM zinc could be detected independent of the tested uptake period. The kinetic constants increased with higher phases and the transition points were lowered with increasing time. The presence of copper did not inhibit the uptake of zinc competitively. On the contrary a slight stimulation in the uptake rates was observed indicating an interaction with the transition site. It is concluded that zinc and copper are taken up by separate mechanisms.