Role of kinetic intermediates in the folding of leech carboxypeptidase inhibitor

The oxidative folding and reductive unfolding pathways of leech carboxypeptidase inhibitor (LCI; four disulfides) have been characterized in this work by structural and kinetic analysis of the acid-trapped folding intermediates. The oxidative folding of reduced and denatured LCI proceeds rapidly through a sequential flow of 1-, 2-, 3-, and 4-disulfide (scrambled) species to reach the native form. Folding intermediates of LCI comprise two predominant 3-disulfide species (designated as III-A and III-B) and a heterogeneous population of scrambled isomers that consecutively accumulate along the folding reaction. Our study reveals that forms III-A and III-B exclusively contain native disulfide bonds and correspond to stable and partially structured species that interconvert, reaching an equilibrium prior to the formation of the scrambled isomers. Given that these intermediates act as kinetic traps during the oxidative folding, their accumulation is prevented when they are destabilized, thus leading to a significant acceleration of the folding kinetics. III-A and III-B forms appear to have both native disulfides bonds and free thiols similarly protected from the solvent; major structural rearrangements through the formation of scrambled isomers are required to render native LCI. The reductive unfolding pathway of LCI undergoes an apparent all-or-none mechanism, although low amounts of intermediates III-A and III-B can be detected, suggesting differences in protection against reduction among the disulfide bonds. The characterization of III-A and III-B forms shows that the former intermediate structurally and functionally resembles native LCI, whereas the III-B form bears more resemblance to scrambled isomers.     

Social structure and life-history patterns in western gorillas (Gorilla gorilla gorilla)

Life-history traits and ecological conditions have an important influence on primate social systems. Most of what we know about the life-history patterns and social structure of gorillas comes from studies of eastern gorillas (Gorilla beringei sp.), which live under dramatically different ecological conditions compared to western gorillas (Gorilla gorilla sp.). In this paper we present new data on western gorilla social structure and life histories from four study sites, and make comparisons with eastern gorilla populations. Data were obtained from two study sites with gorilla groups undergoing the habituation process (Lossi, Democratic Republic of Congo and Bai Hokou, Central African Republic) and two "bai" studies (Maya Nord and Mbeli Bai, Republic of Congo). The size and structure of these groups were similar to those seen in eastern gorillas. However, differences in the occurrence of various group transitions (group formations, changes between one-male and multimale composition, and group disintegrations) exist, and western gorillas notably exhibit much higher rates of male emigration and correspondingly fewer multimale groups compared to mountain gorillas. Certain phenomena have been observed only rarely, including predation by leopards. The preliminary data show no significant differences in birth rates between western gorillas and mountain gorillas. The ecological variability across gorilla habitats likely explains the flexibility in the social system of gorillas, but we need more information on the social relationships and ecology of western gorillas to elucidate the causes for the similarities and differences between western and eastern gorillas on the levels of individuals, social groups, and population dynamics.     

Seasonal Predictability of the East Atlantic Pattern from Sea Surface Temperatures

This study analyzes the influence of sea surface temperatures (SSTs) on the second mode of atmospheric variability in the north Atlantic/European sector, namely the East-Atlantic (EA) pattern, for the period 1950–2012. For this purpose, lead-lag relationships between SSTs and the EA pattern, ranging from 0 to 3 seasons, were assessed. As a main result, anomalies of the EA pattern in boreal summer and autumn are significantly related to SST anomalies in the Indo-Pacific Ocean during the preceding seasons. A statistical forecasting scheme based on multiple linear regression was used to hindcast the EA-anomalies with a lead-time of 1 to 2 months. The results of a one-year-out cross-validation approach indicate that the phases of the EA in summer and autumn can be properly hindcast.     

Genetic and geographical structure in grapevines from northwestern Spain

The grapevine germplasm bank from Estación de Viticultura e Enoloxía de Galicia contains 110 accessions collected from more than 100‐year‐old grapevines from northwestern Spain. We identified 60 different genotypes (among which ‘Pinot Noir’ and ‘Shyrah’ were included as references) with 32 polymorphic microsatellites (SSRs), 21 of which were unlinked SSRs and without null alleles, which were used to detect genetic structure. We found four reconstructed populations that were highly differentiated by analysis of molecular variance (18.3%): (i) western Galician group (‘Caíño Bravo’); (ii) eastern Galician group (‘Merenzao’); (iii) Castilian group (‘Garnacha’) and (iv) southern Spanish group (‘Moscatel’). The greatest genetic differentiation was found between the western Galician/eastern Galician groups and the southern Spanish/Castilian groups, with Fst > 0.13. Western and eastern Galician groups contained most of the ancient Galician cultivars (86%) and included ancestors from central Europe, such as ‘Pinot Noir’ and ‘Shyrah’ in the western Galician group and the introgressant ‘Merenzao’ (French ‘Trousseau’) in the eastern Galician group; the Castilian and southern Spain groups included traditional cultivars from central and southern Spanish and suggest a further introduction of those cultivars in northwestern plantations. Genetic structure corresponded with East‐to‐West geographical differentiation in the northern Iberian Peninsula, following the old path to Santiago de Compostela from France, with the southern Spanish and Castilian groups in the East (Castilian plateau and southern Spain), the eastern Galician group and the western Galician group in the West. Five new relationships were discovered: ‘Caíño Bravo’/‘Caíño Longo2’, ‘Albarín Tinto’/‘Torrontés1’, ‘Treixadura’/‘Treixadura Francesa’, ‘Moscatel’/‘Moscatel de Bago Miúdo’ and ‘Moscatel’/‘Moscatel de Hamburgo’, indicating that hybridisation and further selection by growers have been the origin of most of the genetic diversity found in northwestern Spain.     

Interaction of visual and olfactory cues in the aggregation behaviour of the haematophagous bug Triatoma infestans

We analysed how the assembling behaviour of Triatoma infestans is modulated by the convergence of chemical cues released by their faeces and the spectral quality of the light associated with refuges. Second-instar larvae were confronted with refuges associated with a visual stimulus (either blue, green or red lights having the same intensity, or darkness) and a chemical cue (presence or absence of faeces). In this context, faeces constitute a major attractant for bugs. In the absence of faeces, bugs always assembled in dark places. Green light was always rejected despite the presence of faeces, i.e. the assembling behaviour was controlled by a photonegative reaction to this light. In the presence of red light, orientation towards the chemical cue dominated over the bugs' photonegative reaction to this light. Such a light was avoided in the absence of faeces but not in their presence. Also, negative phototaxis to blue light could be counteracted by the presence of the chemical cue. Thus, a concrete interaction between visual and olfactory cues occurred in these experiments: the bugs' response changed depending on the specific combination of spectral light and faeces. Finally, bugs responded differentially to blue, red and green lights of the same intensity. They assembled preferentially on red, followed by blue and then by green. Thus, discrimination between lights of different spectral quality is possible, probably through an achromatic mechanism.     

Immunolocalization of specific beta‐proteins in pad lamellae of the digits in the lizard Anolis carolinensis suggests that cysteine‐rich beta‐proteins provides flexibility

Knowledge of beta‐protein (beta‐keratin) sequences in Anolis carolinensis facilitates the localization of specific sites in the skin of this lizard. The epidermal distribution of two new beta‐proteins (beta‐keratins), HgGC8 and HgG13, has been analyzed by Western blotting, light and ultrastructural immunocytochemistry. HgGC8 includes 16 kDa members of the glycine‐cysteine medium‐rich subfamily and is mainly expressed in the beta‐layer of adhesive setae but not in the setae. HgGC8 is absent in other epidermal layers of the setae and is weakly expressed in the beta‐layer of other scales. HgG13 comprises members of 17‐kDa glycine‐rich proteins and is absent in the setae, diffusely distributed in the beta layer of digital scales and barely present in the beta‐layer of other scales. It appears that the specialized glycine‐cysteine medium rich beta‐proteins such as HgGC8 in the beta‐layer, and of HgGC10 and HgGC3 in both alpha‐ and beta‐layers, are key proteins in the formation of the flexible epidermal layers involved in the function of these modified scales in adaptation to contact and adhesion on surfaces. J. Morphol. 275:504–513, 2014. © 2013 Wiley Periodicals, Inc.     

Presence and distribution of serotonin in the stomach of the Antarctic silverfish <Emphasis Type="Italic">Pleuragramma antarcticum</Emphasis>

Serotonin is a signal molecule with a wide range of functions in vertebrates. In Antarctic fishes, the serotonergic system has been studied in the brain, revealing differences from temperate fishes related to the long-term cold adaptation. To date, little is known regarding the peripheral nervous system, and no information is available for the stomach. In the present work, we contribute to fill the gaps by investigating the presence and the immunohistochemical distribution of serotonin in the stomach of the Antarctic silverfish Pleuragramma antarcticum, a cold-adapted key species of the Southern Ocean shelf food web. The main aim was to investigate the serotonergic system at the gastric level, in order to reveal possible peculiarities related to long-term cold adaptation, similar to the ones seen in the central nervous system of Antarctic fishes. Serotonin immunoreactivity was detected in the pyloric and cardiac mucosa of P. antarcticum stomach with immunopositive cells in the pyloric and cardiac surface epithelia and in the tubular glands. No immunopositive fibers and neuronal cell bodies were found. Our results highlight that the serotonin distribution pattern at the gastric level is similar to that described in temperate teleosts. This finding suggests that in P. antarcticum, long-term adaptations to the Antarctic condition do not affect the serotonergic system at the gastric level. In addition, our data constitute the baseline information for further investigations aimed at clarifying the effects of short-term temperature variations on the gastric serotonergic system of Antarctic species in the frame of the global climate change.     

Nimodipine confers clinical improvement in two models of experimental autoimmune encephalomyelitis

Multiple sclerosis is characterised by inflammatory neurodegeneration, with axonal injury and neuronal cell death occurring in parallel to demyelination. Regarding the molecular mechanisms responsible for demyelination and axonopathy, energy failure, aberrant expression of ion channels and excitotoxicity have been suggested to lead to Ca²⁺ overload and subsequent activation of calcium‐dependent damage pathways. Thus, the inhibition of Ca²⁺ influx by pharmacological modulation of Ca²⁺ channels may represent a novel neuroprotective strategy in the treatment of secondary axonopathy. We therefore investigated the effects of the L‐type voltage‐gated calcium channel blocker nimodipine in two different models of mouse experimental autoimmune encephalomyelitis (EAE ), an established experimental paradigm for multiple sclerosis. We show that preventive application of nimodipine (10 mg/kg per day) starting on the day of induction had ameliorating effects on EAE in SJL /J mice immunised with encephalitic myelin peptide PLP _139–151, specifically in late‐stage disease. Furthermore, supporting these data, administration of nimodipine to MOG _35–55‐immunised C57BL /6 mice starting at the peak of pre‐established disease, also led to a significant decrease in disease score, indicating a protective effect on secondary CNS damage. Histological analysis confirmed that nimodipine attenuated demyelination, axonal loss and pathological axonal β‐amyloid precursor protein accumulation in the cerebellum and spinal cord in the chronic phase of disease. Of note, we observed no effects of nimodipine on the peripheral immune response in EAE mice with regard to distribution, antigen‐specific proliferation or activation patterns of lymphocytes. Taken together, our data suggest a CNS ‐specific effect of L‐type voltage‐gated calcium channel blockade to inflammation‐induced neurodegeneration.