The Miocene tortoise Testudo catalaunica Bataller, 1926, and a revised phylogeny of extinct species of genus Testudo (Testudines: Testudinidae)

We provide a taxonomic review of the extinct testudinid Testudo catalaunica, based on published and unpublished material from several Miocene (late Aragonian and early Vallesian) sites of the Vallès‐Penedès Basin (north‐east Iberian Peninsula). We show that Testudo catalaunica irregularis is a junior subjective synonym of T. catalaunica, and further provide an emended diagnosis of the latter based on newly reported material. Contrary to some recent suggestions, this emended diagnosis discounts an alternative attribution of T. catalaunica to Paleotestudo. The latter is merely recognized as a subgenus of Testudo, based on a cladistic analysis that assessed the phylogenetic position of all extant and most extinct species of Testudo currently recognized as valid (including T. catalaunica). Our phylogenetic analysis (which recovers the molecular phylogeny of extant Testudo s.l.) supports a taxonomic scheme in which the three extant subgenera of Testudo are represented in the fossil record. Testudo s.s. is retrieved as the sister taxon of Testudo (Agrionemys) + [Testudo (Paleotestudo) + Testudo (Chersine)]. The extinct Testudo (Paleotestudo) is therefore the sister taxon of the Testudo (Chersine) clade. The latter subgenus reveals as the most diverse clade of Testudo s.l. in the fossil record, with T. catalaunica + Testudo steinheimensis constituting a subclade distinct from that including Testudo hermanni.     

Synthesis of peptides containing α,β-didehydroamino acids. Scope and limitations

Summary α, β-Didehydroamino acids, which are key components of both natural andde novo peptides, are frequently encountered in naturally occurring peptides — mostly of microbial and fungal origin and/or from marine organisms. Herein, we report on a reappraisal of the use of the water-soluble carbodiimide/CuCl method for the preparation of this kind of peptide in both solution and solid-phase modes and describe some side reactions encountered during the process. Abbreviations: Alloc, allyloxycarbonyl; Barlos resin, 2-chlorotrityl chloride resin, Boc,tert-butoxycarbonyl; Boc₂O, di-tert-butyl dicarbonate; Bzl, benzyl; DABCO, 1,4-diazabicyclo[2.2.2]octane; DAST, (diethylamino)sulfur trifluoride; DBU, 1,8-diazabicyclo[5.4.0]undec-7-ene; DDAAs, α, β-didehydroarnino acids; DEAD, diethyl azodicarboxylate; Dha, Didehydroalanine, (Z)-Dhb, Z-Didebydroaminobutyric acid; (Z)-Dhp, Z-Didehydrophenylalanine; DSC, disuccinimidyl carbonate; DDP, α, β-didehydropeptides; EDC, WSC, 3-(3′-dimethylaminopropyl)-1-ethylearbodiimide; Fmoc, fiuorenylmethoxycarbonyl; HATU, N-{(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridino-1-ylmethylene}-N-methylmethanaminium hexafluorophosphate; HOAt, 1-hydroxy-7-azabenzotriazole; (β-OH)Phe, phenylserine or β-hydroxyphenylalanine; Ph₃P, triphenylphosphine; PyAOP, (7-azabenzotriazol-1-yloxy)-tris(pyrrolidino)phosphonium hexafluorophosphate; TEA, triethylamine; TFA, trifluoroacetic acid. Amino acid symbols denote thel-configuration unless stated otherwise. All solvent ratios are volume/volume unless stated otherwise.     

Ethnobotany ofSambucus nigra L. in catalonia (Iberian Peninsula): The integral exploitation of a natural resource in mountain regions

Ethnobotany of Sambucus nigraL. in Catalonia (Iberian Peninsula):The Integral Exploitation of a Natural Resource in Mountain Regions. Economic Botany 58(3):456-469, 2004. We present in this paper data about the popular uses of elder (Sambucus nigra) obtained in two ethnobotanical studies carried out in the districts (comarques) of Pallars Jussà and Pallars Sobirà (Pyrenees) and in the Montseny Massif (Catalan Prelittoral Range), complemented with others from different Catalan regions (also investigated by our group) and compared with those from other Iberian and Mediterranean territories. This bush or small tree belonging to the family Caprifoliaceae is one of the plants that have been most reported and used (for medicinal and other purposes) by the informants, not only in the two regions studied but in all Catalonia and in many Mediterranean areas as well. It is one of the most versatile of plants, being used for food, medicine, crafts and games, as well as for ornamental purposes. In addition, almost every part of the plant, including the bark, roots, leaves, flowers, and fruit, has some uses.     

Is stomatal conductance optimized over both time and space in plant crowns? A field test in grapevine (Vitis vinifera)

Crown carbon gain is maximized for a given total water loss if stomatal conductance (g_s) varies such that the marginal carbon product of water (?A/?E) remains invariant both over time and among leaves in a plant crown, provided the curvature of assimilation rate (A) versus transpiration rate (E) is negative. We tested this prediction across distinct crown positions in situ for the first time by parameterizing a biophysical model across 14 positions in four grapevine crowns (Vitis vinifera), computing optimal patterns of g_s and E over a day and comparing these to the observed patterns. Observed water use was higher than optimal for leaves in the crown interior, but lower than optimal in most other positions. Crown carbon gain was 18% lower under measured g_s than under optimal g_s. Positive curvature occurred in 39.6% of cases due to low boundary layer conductance (g_bw), and optimal g_s was zero in 11% of cases because ?A/?E was below the target value at all g_s. Some conclusions changed if we assumed infinite g_bw, but optimal and measured E still diverged systematically in time and space. We conclude that the theory's spatial dimension and assumption of positive curvature require further experimental testing.     

Biophysical properties of Saccharomyces cerevisiae and their relationship with HOG pathway activation

Parameterized models of biophysical and mechanical cell properties are important for predictive mathematical modeling of cellular processes. The concepts of turgor, cell wall elasticity, osmotically active volume, and intracellular osmolarity have been investigated for decades, but a consistent rigorous parameterization of these concepts is lacking. Here, we subjected several data sets of minimum volume measurements in yeast obtained after hyper-osmotic shock to a thermodynamic modeling framework. We estimated parameters for several relevant biophysical cell properties and tested alternative hypotheses about these concepts using a model discrimination approach. In accordance with previous reports, we estimated an average initial turgor of 0.6 ± 0.2 MPa and found that turgor becomes negligible at a relative volume of 93.3 ± 6.3% corresponding to an osmotic shock of 0.4 ± 0.2 Osm/l. At high stress levels (4 Osm/l), plasmolysis may occur. We found that the volumetric elastic modulus, a measure of cell wall elasticity, is 14.3 ± 10.4 MPa. Our model discrimination analysis suggests that other thermodynamic quantities affecting the intracellular water potential, for example the matrix potential, can be neglected under physiological conditions. The parameterized turgor models showed that activation of the osmosensing high osmolarity glycerol (HOG) signaling pathway correlates with turgor loss in a 1:1 relationship. This finding suggests that mechanical properties of the membrane trigger HOG pathway activation, which can be represented and quantitatively modeled by turgor.     

Evolution of age-dependent sex-reversal under adaptive dynamics

We investigate the evolution of the age (or size) at sex-reversal in a model of sequential hermaphroditism, by means of the function-valued adaptive dynamics. The trait is the probability law of the age at sex-reversal considered as a random variable. Our analysis starts with the ecological model which was first introduced and analyzed by Calsina and Ripoll (Math Biosci 208(2), 393–418, 2007). The structure of the population is extended to a genotype class and a new model for an invading/mutant population is introduced. The invasion fitness functional is derived from the ecological setting, and it turns out to be controlled by a formula of Shaw–Mohler type. The problem of finding evolutionarily stable strategies is solved by means of infinite-dimensional linear optimization. We have found that these strategies correspond to sex-reversal at a single particular age (or size) even if the set of feasible strategies is considerably broader and allows for a probabilistic sex-reversal. Several examples, including in addition the population-dynamical stability, are illustrated. For a special case, we can show that an unbeatable size at sex-reversal must be larger than 69.3% of the expected size at death.     

Asymptotic behaviour of a model of hierarchically structured population dynamics

 A hierarchically structured population model with a dependence of the vital rates on a function of the population density (environment) is considered. The existence, uniqueness and the asymptotic behaviour of the solutions is obtained transforming the original non-local PDE of the model into a local one. Under natural conditions, the global asymptotical stability of a nontrivial equilibrium is proved. Finally, if the environment is a function of the biomass distribution, the existence of a positive total biomass equilibrium without a nontrivial population equilibrium is shown. Received 16 February 1996; received in revised form 16 September 1996