A new species of the cheilostome bryozoan Chiastosella in the Southern Ocean,past and present

Understanding whether marine calcifying organisms may acclimatise to climate change is important with regard to their survival over the coming century. Due to cold waters having a naturally higher CO₂ uptake, the Southern Ocean provides an especially good opportunity to study the potential impact of climate change. In 2011, a new cheilostome bryozoan species—Chiastosella ettorina sp. nov.—was dredged from Burdwood Bank, Southern Ocean, at 324–219-m depth during the Nathaniel B Palmer Cruise. This species had previously been collected in 1902 from the same area at 100-m depth, but was incorrectly identified as Chiastosella watersi, an encrusting species from New Zealand. The availability of samples of the same species, from the same general location, but collected 109 years apart allowed us to investigate morphological modifications potentially arising from environmental changes. We found a significant difference in zooid size, with the oldest and shallowest specimens having smaller zooids than the recently collected deeper specimens. This difference in zooid size appears to be unrelated to known sources of environmental variation such as temperature and salinity, and it could represent the extremes of the zooid size range of C. ettorina. An alternative explanation is that acidifying waters may have caused zooids to grow more slowly, resulting in a final larger size.     

Effects of grapevine bunch exposure to sunlight on berry surface temperature and Lobesia botrana (Lepidoptera: Tortricidae) egg laying,hatching and larval settlement

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Immunohistology of gastrointestinal carcinoid tumors

DAKO quick staining kits were used to immunostainings for Epithelial Membrane Antigen (EMA) Neuron Specific Enolase (NSE) and S-100 protein (S-100) in 18 carcinoid tumors of the gastrointestinal tract classified according to Soga and Tazawa. EMA was always absent in carcinoid tumors, being at the same time present within glandular epithelium. 88% of cases showed positive immunostaining for NSE. S-100 immunostaining showed immunopositive stellate cells present within the tumor especially within type A carcinoids. In addition in one carcinoid tumor thick, strongly S-100 positive bundles were noticed at the periphery of nests of tumor cells. Combined immunohistochemical and ultrastructural studies are needed to elucidate interrelation of neoplastic and neural elements within carcinoid tumorsa.     

Sperm ultrastructure of<Emphasis Type="Italic"> Mantophasma zephyra</Emphasis> (Insecta,Mantophasmatodea)

The ultrastructure of Mantophasma zephyra spermatozoa is described. Sperm cells have a trilayered acrosome with conspicuous extra-acrosomal material which expands along the nucleus. The nucleus is crossed anteriorly by a canal and its posterior end is embedded in the centriole adjunct material. A centriole with microtubular triplets is present. The flagellum has a 9+9+2 axonemal pattern, two partially crystallised mitochondrial derivatives, two membranous sacs and three connecting bands. The accessory microtubules are filled with dense material and have 16 protofilaments in their tubular wall. The intertubular material is not very expanded. In the seminal vesicles spermatozoa are stuck together to form spermatodesms, and their heads are also joined by adherens junctions. A cladistic analysis based on sperm features indicates a close relationship of Mantophasmatodea with Mantodea.     

Bisphenol-A Impairs Insulin Action and Up-Regulates Inflammatory Pathways in Human Subcutaneous Adipocytes and 3T3-L1 Cells

Current evidence indicates that chemical pollutants may interfere with the homeostatic control of nutrient metabolism, thereby contributing to the increased prevalence of metabolic disorders. Bisphenol-A (BPA) is a lipophilic compound contained in plastic which is considered a candidate for impairing energy and glucose metabolism. We have investigated the impact of low doses of BPA on adipocyte metabolic functions. Human adipocytes derived from subcutaneous adipose tissue and differentiated 3T3-L1 cells were incubated with BPA, in order to evaluate the effect on glucose utilization, insulin sensitivity and cytokine secretion. Treatment with 1nM BPA significantly inhibited insulin-stimulated glucose utilization, without grossly interfering with adipocyte differentiation. Accordingly, mRNA levels of the adipogenic markers PPARγ and GLUT4 were unchanged upon BPA exposure. BPA treatment also impaired insulin-activated receptor phosphorylation and signaling. Moreover, adipocyte incubation with BPA was accompanied by increased release of IL-6 and IFN-γ, as assessed by multiplex ELISA assays, and by activation of JNK, STAT3 and NFkB pathways. Treatment of the cells with the JNK inhibitor SP600125 almost fully reverted BPA effect on insulin signaling and glucose utilization. In conclusion, low doses of BPA interfere with inflammatory/insulin signaling pathways, leading to impairment of adipose cell function.     

Targeting integrins: insights into structure and activity of cyclic RGD pentapeptide mimics containing azabicycloalkane amino acids

A small library of cyclic RGD pentapeptide mimics incorporating stereoisomeric 5,6- and 5,7-fused bicyclic lactams was synthesized. This library was found to contain high-affinity ligands for the alpha(v)beta3 integrin. The aim of this study was to investigate activity, selectivity, and structure of these ligands in order to identify new specific alpha(v)-integrin antagonists that could be evaluated as tumor angiogenesis inhibitors. In vitro screening, including receptor-binding assays to purified alpha(v)beta3, alpha(v)beta5, and alpha5beta1 integrins, and platelet aggregation assay, revealed ST1646 as a potent, highly selective alpha(v)beta3/alpha(v)beta5 integrin antagonist. Structure determination of the cyclic RGD pentapeptide mimics performed by a combination of NMR spectroscopy, and molecular mechanics and dynamics calculations showed a strong dependence of the RGD cyclopeptide conformation on lactam ring size and stereochemistry. ST1646 revealed the highest ability within the library to adopt the proper RGD orientation required for binding to the alpha(v)beta3 integrin, as deduced from the recently solved crystal structure of the extracellular segment of integrin alpha(v)beta3 in complex with a cyclic pentapeptide ligand.     

The role of floral structure and biotic factors in determining the occurrence of florivorous thrips in a dystilous shrub

Elucidating the factors determining the occurrence of florivorous organisms is an essential step for comprehending arthropod–plant interactions, especially when considering florivores that use flowers/inflorescences as microhabitats. In this study, we characterize the interaction between florivorous thrips (Thysanoptera) and Palicourea rigida (Rubiaceae), a distylous hummingbird-pollinated shrub. We investigated the relative role of different factors in determining thrips occurrence in the flower and inflorescence microhabitats. Furthermore, we experimentally examined the protective role of corolla influencing thrips exploration of floral buds. Frankliniella musaeperda (Thripidae) was the only species recorded on P. rigida, feeding on floral tissue, pollen and nectar. Thrips occurrence was not related to distyly, but rather to floral stage. Open flowers presented the highest abundance of thrips, followed by senescent flowers and then buds. The experimental opening of buds translated in increased thrips occurrence, indicating that F. musaeperda manage to explore the microhabitat offered by the floral chamber, as long as there is an opening in the corolla. In inflorescences, thrips abundance was negatively related to the number of ants visiting extrafloral nectaries. We found that the marked difference between floral morphs of distylous plants is not necessarily reflected in the abundance of florivores. Thrips seek for floral cavities, preferentially those with fresh tissue, which may confer nutrient-rich food and protection. Buds also provide this; however, the enclosed petals are an effective barrier against F. musaeperda entrance. At inflorescence scale, presence of mutualistic ants in high numbers can drive away these flower-feeding insects. Despite the abundance of thrips in the flowers, there was no evidence of any functional relationship, either of pollination for flowers or of breeding for insects. We demonstrate here that in the flower/inflorescence microhabitat, structural and biotic factors play a key role in the exploitation and occupation by insect florivores.     

Enhanced Amphiphilic Profile of a Short β-Stranded Peptide Improves Its Antimicrobial Activity

SB056 is a novel semi-synthetic antimicrobial peptide with a dimeric dendrimer scaffold. Active against both Gram-negative and -positive bacteria, its mechanism has been attributed to a disruption of bacterial membranes. The branched peptide was shown to assume a β-stranded conformation in a lipidic environment. Here, we report on a rational modification of the original, empirically derived linear peptide sequence [WKKIRVRLSA-NH₂, SB056-lin]. We interchanged the first two residues [KWKIRVRLSA-NH₂, β-SB056-lin] to enhance the amphipathic profile, in the hope that a more regular β-strand would lead to a better antimicrobial performance. MIC values confirmed that an enhanced amphiphilic profile indeed significantly increases activity against both Gram-positive and -negative strains. The membrane binding affinity of both peptides, measured by tryptophan fluorescence, increased with an increasing ratio of negatively charged/zwitterionic lipids. Remarkably, β-SB056-lin showed considerable binding even to purely zwitterionic membranes, unlike the original sequence, indicating that besides electrostatic attraction also the amphipathicity of the peptide structure plays a fundamental role in binding, by stabilizing the bound state. Synchrotron radiation circular dichroism and solid-state ¹⁹F-NMR were used to characterize and compare the conformation and mobility of the membrane bound peptides. Both SB056-lin and β-SB056-lin adopt a β-stranded conformation upon binding POPC vesicles, but the former maintains an intrinsic structural disorder that also affects its aggregation tendency. Upon introducing some anionic POPG into the POPC matrix, the sequence-optimized β-SB056-lin forms well-ordered β-strands once electro-neutrality is approached, and it aggregates into more extended β-sheets as the concentration of anionic lipids in the bilayer is raised. The enhanced antimicrobial activity of the analogue correlates with the formation of these extended β-sheets, which also leads to a dramatic alteration of membrane integrity as shown by ³¹P-NMR. These findings are generally relevant for the design and optimization of other membrane-active antimicrobial peptides that can fold into amphipathic β-strands.