Anatomy of the antennal dorsal organ in female of Neodryinus typhlocybae (Hymenoptera: Dryinidae): A peculiar sensory structure possibly involved in perception of host vibration

Neodryinus typhlocybae (Hymenoptera: Dryinidae) is a natural enemy of the planthopper Metcalfa pruinosa, which was introduced from North America into Europe and has become established in various regions as a pest species. Vibrational signals play a crucial role in the communication of M. pruinosa, which appears to be exploited by N. typhlocybae. Scanning and transmission electron microscopy have shown that the antennae of N. typhlocybae females have peculiar and complex sensory structures: deep longitudinal grooves that house long sensilla trichodea, termed here “Antennal Dorsal Organs.” Such structures were not present on male antennae. These sensilla extend for the length of the grooves, without contact with the groove cuticle. Their hair shaft is empty and aporous, and inserted into a specialized socket, underneath which there is a cuticular ampulla‐like chamber. Each sensillum is associated with two sensory neurons: one terminates at the proximal end of the dendritic sheath; the other continues into the sensillum sinus and is enclosed in the dendritic sheath. This second sensory neuron then enters the ampulla‐like chamber through the circular opening, and then terminates with a conspicuous tubular body at the shaft base. The possible involvement of this peculiar structure in the context of host recognition mechanism is discussed. J. Morphol. 277:128–137, 2016. © 2015 Wiley Periodicals, Inc.     

DNA repair after gamma irradiation in lymphocytes exposed to low-frequency pulsed electromagnetic fields

The effect of exposure to extremely low-frequency pulsed electromagnetic fields (EMFs) on DNA repair capability and on cell survival in human lymphocytes damaged in vitro with gamma rays was studied by two different micromethods. In the first assay, which measures DNA repair synthesis (unscheduled DNA synthesis, UDS), lymphocyte cultures were stimulated with phytohemagglutinin (PHA) for 66 h and then treated with hydroxyurea (which blocks DNA replication), irradiated with 100 Gy of 60Co, pulsed with [3H]thymidine ([3H]TdR), and then exposed to pulsed EMFs for 6 h (the period in which cells repaired DNA damage). In the second assay, which measures cell survival after radiation or chemical damage, lymphocytes were first irradiated with graded doses of gamma rays or treated with diverse antiproliferative agents, and then stimulated with PHA, cultured for 72 h, and pulsed with [3H]TdR for the last 6 h of culture. In this case, immediately after the damage induced by either the radiation or chemicals, cultures were exposed to pulsed EMFs for 72 h, during which cell proliferation took place. Exposure to pulsed EMFs did not affect either UDS or cell survival, suggesting that this type of nonionizing radiation--to which humans may be exposed in the environment, and which is used for both diagnostic and therapeutic purposes--does not affect DNA repair mechanisms.     

Application of X-ray microanalysis to cell suspensions of oil palm (Elaeis guineensis Jacq.)

X-ray microanalysis has been used to determine the elemental composition of oil-palm (Elaeis guineesis) cell suspensions without the use of cryoprotectants. Results based on individual cells were gathered over a typical growth cycle of 14 d. During the log phase (5–7 d) there is an increase in the number of cells containing high concentrations of both K (400 mmol kg^-1 dry weight) and P (400 mmol kg^-1 dry weight). Morphologically these cells had thin cell walls and were frequently joined to other cells (two to five cells per clump).     

Complete sequences of glucagon-like peptide-1 from human and pig small intestine

In the small intestine, proglucagon is processed into the previously characterized peptide "glicentin" (proglucagon (PG) 1-69) and two smaller peptides showing about 50% homology with glucagon: glucagon-like peptide-1 and -2. It was assumed that the sites of post-translational cleavage in the small intestine of the proglucagon precursor were determined by pairs of basic amino acid residues flanking the two peptides. Earlier studies have shown that synthetic glucagon-like peptide-1 (GLP-1) synthesized according to the proposed structure (proglucagon 71-108 or because residue 108 is Gly, 72-107 amide) had no physiological effects, whereas a truncated from of GLP-1, corresponding to proglucagon 78-107 amide, strongly stimulated insulin secretion and depressed glucagon secretion. To determine the amino acid sequence of the naturally occurring peptide we isolated GLP-1 from human small intestine by hydrophobic, gel permeation, and reverse-phase high performance liquid chromatography. By analysis of composition and sequence it was determined that the peptide corresponded to PG 78-107. By mass spectrometry the molecular mass was determined to be 3295, corresponding to PG 78-107 amide. Furthermore, mass spectrometry of the methyl-esterified peptide showed an increase in mass compatible with the presence of alpha-carboxyl amidation. Thus, the gut-derived insulinotrophic hormone GLP-1 is shown to be PG 78-107 amide.     

Tissue and subcellular immunolocalisation of enzymes of lignin synthesis in differentiating and wounded hypocotyl tissue of French bean (Phaseolus vulgaris L.)

Antisera raised againstl-phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and a cationic cell-wall peroxidase, which had all been purified from suspension-cultured cells of French bean, have been used to carry out immunogold localisations in the growing plant. Immunoglobulin-G fractions were prepared from each antiserum and used to study the distribution of the enzymes in differentiating and wounded hypocotyls by immunogold techniques and visualisation by both light and electron microscopy. Following silver enhancement to amplify the signal, proteins were detected by confocal microscopy in both developing (pre-xylem/ phloem) and later metaxylem stelar tissue.l-Phenylalanine ammonia-lyase and C4H also accumulated in cells adjacent to metaxylem, presumably involved in maintaining a supply of phenylpropanoid precursors to the enucleated xylem for further lignin synthesis. In these cells, PAL subunits were cytosolic although some were associated with endomembrane. Cinnamate-4-hydroxylase was wholly associated with membrane and particularly high concentrations were found in the Golgi bodies. The cationic peroxidase accumulated in xylem at sites of secondary thickening and in the middle lamella. The three proteins are also involved in defensive lignification. Thus when visualised by light microscopy, PAL and C4H were seen to accumulate to high levels throughout the cell types in wound sites and especially in the epidermal cells. An even more intense general distribution was found upon hyperinduction of wounded cells with-aminooxy--phenylpropionic acid. At the subcellular level, PAL was found to be localised in the cytosol in the wounded cells; however, because of the loss of membrane through mechanical damage, association with membrane structures, particularly endoplasmic reticulum, in unwounded cells is not entirely ruled out. Cinnamate-4-hydroxylase was associated with membranes when these were preserved. In wounded tissue, the peroxidase was found at the growing edges of tylose-like structures in the vascular xylem.Abbreviations AOPP -aminooxy--phenylpropionic acid - C4H cinnamic acid-4-hydroxylase - CHS chalcone synthase - GRP glycine-rich glycoprotein - HRGP hydroxyproline-rich glycoprotein - Ig immunoglobulin - PAL phenylalanine ammonia-lyase G.P.B. thanks the Agicultural and Food Research Council for support.     

Detailed finite element modelling of deep needle insertions into a soft tissue phantom using a cohesive approach

Detailed finite element modelling of needle insertions into soft tissue phantoms encounters difficulties of large deformations, high friction, contact loading and material failure. This paper demonstrates the use of cohesive elements in high-resolution finite element models to overcome some of the issues associated with these factors. Experiments are presented enabling extraction of the strain energy release rate during crack formation. Using data from these experiments, cohesive elements are calibrated and then implemented in models for validation of the needle insertion process. Successful modelling enables direct comparison of finite element and experimental force–displacement plots and energy distributions. Regions of crack creation, relaxation, cutting and full penetration are identified. By closing the loop between experiments and detailed finite element modelling, a methodology is established which will enable design modifications of a soft tissue probe that steers through complex mechanical interactions with the surrounding material.     

How Skill Expertise Shapes the Brain Functional Architecture: An fMRI Study of Visuo-Spatial and Motor Processing in Professional Racing-Car and Na?ve Drivers

The present study was designed to investigate the brain functional architecture that subserves visuo-spatial and motor processing in highly skilled individuals. By using functional magnetic resonance imaging (fMRI), we measured brain activity while eleven Formula racing-car drivers and eleven ‘naïve’ volunteers performed a motor reaction and a visuo-spatial task. Tasks were set at a relatively low level of difficulty such to ensure a similar performance in the two groups and thus avoid any potential confounding effects on brain activity due to discrepancies in task execution. The brain functional organization was analyzed in terms of regional brain response, inter-regional interactions and blood oxygen level dependent (BOLD) signal variability. While performance levels were equal in the two groups, as compared to naïve drivers, professional drivers showed a smaller volume recruitment of task-related regions, stronger connections among task-related areas, and an increased information integration as reflected by a higher signal temporal variability. In conclusion, our results demonstrate that, as compared to naïve subjects, the brain functional architecture sustaining visuo-motor processing in professional racing-car drivers, trained to perform at the highest levels under extremely demanding conditions, undergoes both ‘quantitative’ and ‘qualitative’ modifications that are evident even when the brain is engaged in relatively simple, non-demanding tasks. These results provide novel evidence in favor of an increased ‘neural efficiency’ in the brain of highly skilled individuals.