Atomic force microscope (AFM) combined with the ultramicrotome: a novel device for the serial section tomography and AFM/TEM complementary structural analysis of biological and polymer samples

A new device (NTEGRA Tomo) that is based on the integration of the scanning probe microscope (SPM) (NT‐MDT NTEGRA SPM) and the Ultramicrotome (Leica UC6NT) is presented. This integration enables the direct monitoring of a block face surface immediately following each sectioning cycle of ultramicrotome sectioning procedure. Consequently, this device can be applied for a serial section tomography of the wide range of biological and polymer materials. The automation of the sectioning/scanning cycle allows one to acquire up to 10 consecutive sectioned layer images per hour. It also permits to build a 3‐D nanotomography image reconstructed from several tens of layer images within one measurement session. The thickness of the layers can be varied from 20 to 2000 nm, and can be controlled directly by its interference colour in water. Additionally, the NTEGRA Tomo with its nanometer resolution is a valid instrument narrowing and highlighting an area of special interest within volume of the sample. For embedded biological objects the ultimate resolution of SPM mostly depends on the quality of macromolecular preservation of the biomaterial during sample preparation procedure. For most polymer materials it is comparable to transmission electron microscopy (TEM). The NTEGRA Tomo can routinely collect complementary AFM and TEM images. The block face of biological or polymer sample is investigated by AFM, whereas the last ultrathin section is analyzed with TEM after a staining procedure. Using the combination of both of these ultrastructural methods for the analysis of the same particular organelle or polymer constituent leads to a breakthrough in AFM/TEM image interpretation. Finally, new complementary aspects of the object's ultrastructure can be revealed.     

DETERMINISTIC AND N0NDETERMIN1STIC PROGRAMMING IN ROBOT SYSTEMS

The modem results of artificial intelligence research have provided new techniques useful foi the design of more sophisticated and advanced industrial robots. The use of computer integrated assembly systems is becoming more and more important in industrial applications

The purpose of this paper is to illustrate how with the use of an automatic problem solver it is possible to achieve the automatic emergency recovery from a failure occurring during the assembly process. An experimental computer program implementing the required problem solving activity has been written in MICROPLANNER and tested on a UNIVAC 1108 computer.     

DETECTION OF VIBRIO ALGINOLYTICUS AND VIBRIO PARAHAEMOLYTICUS IN SHELLFISH SAMPLES USING COLLAGENASE-TARGETED MULTIPLEX-PCR

The increase of Vibrio infections especially associated with the consumption of contaminated seafood and fish underlines the necessity of an efficient monitoring system for Vibrio spp. supported by appropriate detection tools both in food products and in clinical samples. The aim of this study was the evaluation of the reliability of the collagenase‐targeted multiplex‐polymerase chain reaction (m‐PCR) for the detection of Vibrio alginolyticus, Vibrio cholerae and Vibrio parahaemolyticus in shellfish samples enriched in alkaline peptone water (APW). The coupling of a pre‐enrichment phase of the samples with the specificity of the PCR‐based assay was applied successfully to the detection of V. alginolyticus and V. parahaemolyticus, demonstrating that collagenase‐target m‐PCR may be used as a valid molecular target to discriminate the three Vibrio species.     

MUSCLE AND ROE LIPID COMPOSITION IN DIPLOID AND TRIPLOID SCALLOPS

The use of triploid bivalves is now common in the market. We tested if there was a difference in lipid and long-chain highly unsaturated fatty acid (HUFA) accumulation in the muscle of diploid and triploid scallops ( Argopecten ventricosus ) during maturation, as triploids do not reproduce and lipids are not transferred to the gonad, and thus, could be accumulated in the meat (adductor muscle). Differences in triacylglycerols, phospholipids, esterified and free sterols, as well as HUFA in the reserves of gonads were found between diploid and triploid scallops. In contrast, no differences were found in the muscle for any of the lipid classes or fatty acid content in relation to ploidy, although they varied in relation to the sampling month.

PRACTICAL APPLICATIONS

The results obtained indicate that for human consumption purposes, the quality of the meat and roe of scallops follows a temporal pattern of lipid accumulation, with higher levels of total sterols in summer, but a higher proportion of arachidonic acid in winter and lower docosahexaenoic acid in autumn, and that the muscle lipid composition is not affected by the triploid condition.     

ABSENCE OF PROTEOLYSIS IN PURIFIED MYOFIBRILS OF POSTSPAWNED HAKE (MERLUCCIUS HUBBSI MARINI) DURING IN VITRO STORAGE AT 37C

The biochemical behavior of myofibrils from postspawned hake during in vitro storage at 37C was investigated. SDS‐PAGE, densitometric analysis of the band areas corresponding to the major myofibrillar proteins, and TCA soluble peptides determination showed no evidence of proteolysis in myofibrils after 44 h of incubation either in presence or in absence of a cocktail of protease inhibitors (1 mMPMSF+1mMiodoacetic acid + 1mM of EDTA). The absence of proteolysis in stored postspawned hake myofibrils contrasts with the autolysis in those from prespawned fish previously reported, indicating an influence of the reproductive cycle on the proteolytic activity closely associated to myofibrils.