Karyological and morphometric variation of the North African green frog Pelophylax saharicus (Anura) in northeastern Africa

Morphometric variation of Pelophylax saharicus was analysed using univariate and multivariate statistics, with both traditional and geometric morphometries, based on 148 specimens from four different geographical localities in Tunisia and Algeria. The results show the existence of three morphotypes in Tunisia and one in Algeria, and indicate a significant degree of variation in morphometric characters between regions. Specimens from the southernmost region have the smallest body size and the greatest morpho...     

Late Pleistocene skeleton of Canis lupus l., 1758 from Grotta Mora Cavorso (Jenne,Latium, central Italy)

This paper describes the skeleton of Canis lupus found in Layer 7 of Grotta Mora Cavorso (Latium, central Italy), correlated with the MIS 3. Research on the deposition dynamics of this find is still in progress, but the action of human or other predators can be excluded. This specimen consists of a near complete articulated skeleton, lacking only the calvarium. The age at death was estimated at around six years old. Preliminary morphometric analyses and comparisons with samples of Italian Late Pleistocene wolf and extant Apennine wolf (C. lupus italicus) remains, show that the dimensions of the teeth and long bones are among the biggest known from the Italian Late Pleistocene and larger than the extant Apennine wolf.     

Use of single analytic tool to quantify both absolute N-glycosylation and glycan distribution in monoclonal antibodies

Recombinant proteins represent almost half of the top selling therapeutics—with over a hundred billion dollars in global sales—and their efficacy and safety strongly depend on glycosylation. In this study, we showcase a simple method to simultaneously analyze N-glycan micro- and macroheterogeneity of an immunoglobulin G (IgG) by quantifying glycan occupancy and distribution. Our approach is linear over a wide range of glycan and glycoprotein concentrations down to 25 ng/mL. Additionally, we present a case study demonstrating the effect of small molecule metabolic regulators on glycan heterogeneity using this approach. In particular, sodium oxamate (SOD) decreased Chinese hamster ovary (CHO) glucose metabolism and reduced IgG glycosylation by 40% through upregulating reactive oxygen species (ROS) and reducing the UDP-GlcNAc pool, while maintaining a similar glycan profile to control cultures. Here, we suggest glycan macroheterogeneity as an attribute should be included in bioprocess screening to identify process parameters that optimize culture performance without compromising antibody quality.     

Stimulation-induced changes at crayfish (Procambarus clarkii) neuromuscular terminals

Summary The fine structure of neuromuscular terminals of the single excitor axon was examined in the limb stretcher muscle of the crayfish Procambarus clarkii. A morphometric comparsion of the neuromuscular terminals of the left and right limbs of a control crayfish showed them to be similiar in qualitative as well as quantitative features. The excitor axon to the stretcher muscle of the right side was stimulated, by backfiring its branches in the adjacent opener muscle, at 20 Hz for 4–5 h per day over 4–5 days. The stretcher muscle on the left side was not stimulated and served as a control. Morphometric analysis of stimulated terminals revealed an increase in the number of dense bars and synaptic vesicles compared to their non-stimulated, contralateral counterparts. Since dense bars are regarded as active sites of transmitter release, changes in their number provide a morphological basis for synaptic plasticity.     

From glacial refugia to hydrological microrefugia: Factors and processes driving the persistence of the climate relict tree Zelkova sicula

With only two tiny populations, the climate relict Zelkova sicula (Sicily, Italy) is one of the rarest trees in the world. It also represents the most marginal member of genus Zelkova that was widespread in the broadleaved forests thriving in warm–temperate climates throughout Eurasia until the Last Glacial Age. Occurring at the westernmost range of the genus under typical Mediterranean climate, the micro‐topographic settings have always appeared crucial for the survival of this relict. However, the factors and processes actually involved in its persistence in the current refugia, as well as the response of similar relict trees in arid environments, are poorly understood worldwide. In the aim to elucidate these aspects, in the two sites hosting Z. sicula analyses of topographical attributes were combined with investigations on soil moisture dynamics. Additionally, plants’ growth and spatial distribution patterns were analyzed to detect fine‐scale differences between populations and assess the possible ecological amplitude of the species. Results revealed that convergent topographies are basic determinants of microrefugia in arid environments. Within the investigated sites, underground moisture never decreases below 25%, buffering seasonal rainfall fluctuations. Therefore, hydrological microrefugia play a key role in decoupling from regional climate, supporting the target species in coping with an unsuitable climatic envelope. Additionally, the inter‐population variability of biometric attributes showed that individual growth is site‐dependent and the species retains a relative ecological plasticity, whereas the strongly clumped spatial patterns confirmed the common clonal growth. On one hand, deeply incised landforms have acted as effective hydrologic microrefugia, on the other clonality coupled with triploidy supposedly improved the resistance of Z. sicula to harsh environments, though entailing inability to reproduce sexually. Most likely, sterility and environmental/physical barriers that have existed for millennia have prevented this relict from leaving the last suitable microrefugia, resulting in the two current rear edge populations.     

Evolution of the coccolith genus Lotharingius during the Late Pliensbachian-Early Toarcian interval in Asturias (N Spain). Consequences of the Early Toarcian environmental perturbations

The evolution of the coccolith genus Lotharingius was investigated in 18 samples from the West Rodiles section (Asturias, Northern Spain), Upper Pliensbachian-Lower Toarcian in age. In each sample, the length and width of the coccolith and of its central area were measured on 150 specimens of Lotharingius. A total of 2700 specimens were measured, and 10,800 measurements were obtained. Based on the results of the morphometric analysis, the stratigraphic ranges, the abundance patterns and the light microscope observations, the aims of this work are to determine whether the specimens analysed correspond to different species, to distinct ecophenotypes or to an anagenetic lineage of morphotypes of a single species with overlapping stratigraphic ranges, and to test the influence of the paleoenvironmental perturbations during the Early Toarcian on the studied genus. Three species of Lotharingius were distinguished: L. hauffii, L. sigillatus and L. crucicentralis. Based on central area size and structure, two morphotypes (A and B) of L. hauffii were differentiated. All the parameters measured show a great overlap between the morphotypes and species. An increase in both coccolith and central area size and a development of more complex central area structures were observed through the studied section. L. hauffii is the smallest form, followed by L. sigillatus, and finally L. crucicentralis is the largest species and has the most complex central area structure. A clear decrease in size or “dwarfing” of the species was observed in the samples corresponding to the Early Toarcian environmental perturbations. L. crucicentralis was not identified in these samples. We hypothesize that the changes in size and abundance of the Lotharingius species could be related to the unfavourable palaeoenvironmental conditions for the biomineralization of their coccoliths.     

A morphometric study on the pars intermedia of the hypophysis during impairment of the renin-angiotensin-aldosterone system in sodium depleted mice

Fine structural alterations were investigated in cells of the pars intermedia of the pituitary of mice treated for four weeks with (a) a sodium deficient diet, (b) a sodium deficient diet mixed with propranolol (renin-inhibitor), (c) a sodium deficient diet combined with propranolol and amino-glutethimide (corticosterone 18-hydroxylase inhibitor), and (d) a sodium deficient diet combined with propranolol, aminoglutethimide and dexamethasone. The number of secretory granules decreased from 5.0/mum2 in the normal control of 2.4/mum2 in all four experimental groups suggesting that the cells in treated groups had reached an equilibrium in the production and release of secretory granules during the chronic treatments. The number of immature Golgi granules per unit Golgi area was 0.91 in the control, while this value rose to 3.29 (3.62 fold of the control), 4.37 (4.8 fold), 4.94 (5.43 fold) and 5.16 (5.67 fold) respectively in the four experimental groups. In these groups a good correlation was observed between the number of immature granules and the percent volume of rough endoplasmic reticulum (r=0.985, p less than 0.01). The present study suggests that the pars intermedia contains an unidentified pituitary factor (or factors) essential for aldosterone biosynthesis.     

The effect of spatial pattern on community dynamics; a comparison of simulated and field data

The effect of the spatial limits of dispersal and competition on plant community dynamics was studied using Monte-Carlo simulation. The model generates community point patterns, using life-table data, dispersion parameters and radii of competitive effects. These data have been estimated in a field situation, for the 11 most abundant weed species growing on the refuse soil dumps of a strip coal mine. In a simulation experiment, the patterns produced by two versions of the model were compared. The first was based on the field situation as much as possible; the other used the same input parameters except for dispersal, which was randomized in this case. We found considerable differences regarding the temporal changes of species abundances, the realized competitive abilities and the spatial patterns generated by the two versions. An important conclusion of this comparison is that the realized competitive effect (both intra-and interspecific) of a species is dependent not only on constant competition parameters, but on the abundance relations and on the spatial patterns of the competing populations as well. It is concluded that the spatial limits of dispersal and competition may result in the increased persistence of weak competitors, moderate the realized competitive effects of strong species, and shape the spatial coalition structure of the community.