Electron microscopy—The U.K. involvement

The development of the electron microscope in the advanced form we know today is the result of a loosely organized but effective world-wide scientific and technological collaboration, that readily transcends national and cultural barriers. The birth of the subject was undoubtedly in Berlin but the United Kingdom has played a prominent part, sometimes in an accidental way, at critical periods in this development both at the scientific and manufacturing level. In 1927, for example, G.P. Thompson established experimentally the wave nature of the electron and its scattering and diffraction by thin foils. This followed his invention of the electron diffraction camera at a time when De Broglie's postulates on the wave of nature of the electron were not enjoying much support, even in his native France. C.W. Oatley in Cambridge University was successful in introducing the first commercial scanning electron microscope (SEM) where several commercial firms had previously failed. D. Gabor invented electron holography in a moment of boredom while watching a tennis match. The U.K. has also played a key role in fostering international collaboration by means of conferences and exchange visits between electron microscopists. The present paper concentrates on some of the critical developments that took place in the U.K. in the commercial development of transmission electron microscopy, in scanning electron microscopy and more recently in high resolution electron microscopy. These developments are placed as far as possible in a world-wide context.     

The C. U. Ariëns Kappers brain collection

The C. U. Ari?ns Kappers brain collection, at the Netherlands Institute for Neuroscience in Amsterdam, is one of the largest and oldest of the world's catalogued repositories of specimens that reveal the course of brain evolution and the resulting panoply of neural biodiversity. Established a century ago, it has served since then as the basis of the encyclopedic texts authored by its founder, as well as research publications into the current time. It consists of 726 specimens: these include 309 mammals, 134 birds, 81 reptiles, 21 amphibians, and 179 "pisces"--a grouping of bony fish, sharks, and cyclostomes. We present here accounts of the history and contents of this treasure trove of research materials.     

α-l-Fucosidase in human fibroblasts. I. The enzyme activity polymorphism

Low plasma α-l-fucosidase activity is a recessive polymorphic trait observed in 8% of the normal population. The molecular basis of this polymorphism remains unclear and its expression is tissue specific. As the low-activity (variant) phenotype is expressedin vitro in cultured human fibroblasts, this cell type was chosen to study the enzyme activity polymorphism. Fibroblast cell lines derived from individuals with low plasma fucosidase activity (variants) have less than 30% of the fucosidase activity of fibroblast cell lines established from individuals with high plasma fucosidase activity (nonvariants). No qualitative differences in the synthesis, processing, and extracellular release of newly made α-l-fucosidase could be demonstrated among variant and nonvariant cell strains. Cells pulsed with³H-leucine for 10 min produce a 51-kDa protein which is rapidly processed to a 55-kDa intermediate. The latter is converted to a mature 59-kDa intracellular and a 61-kDa extracellular end product, in both variant and nonvariant fibroblast cell lines. Variant and nonvariant fibroblast cell lines also release relatively equal amounts of fucosidase into the extracellular medium. Therefore, differences in processing or extracellular release of fucosidase between variants and nonvariants are not the basic mechanism of this tissue-specific activity polymorphism. We are indebted to the “Belgische Vereniging voor Strijd tegen Mucoviscidose” for financial support.     

The amino acid sequence of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015

The amino acid sequence of the cytochrome c' from Alcaligenes sp. N.C.I.B. 11015 (Iwasaki's ;Pseudomonas denitrificans') has been determined. This organism is the only non-photosynthetic bacterium in which the protein has been found. The protein consists of a single polypeptide chain of 127 residues, with a single haem covalently attached to two cysteines. Unlike normal cytochromes c, the haem attachment site is very close to the C-terminus. The amino acid sequence around the haem attachment site is very similar to that of Chromatium vinosum D cytochrome c'. Detailed evidence for the amino acid sequence of the protein has been deposited as Supplementary Publication SUP 50022 at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.     

Huntington's chorea. The Liège experience

The hereditary choreas are studied in Liège since twenty-five years. The records of psychiatric hospitals (ruled by the belgian law on confinement, 1850-1873), the archives of the "Etat-Civil" (since 1806) and the parochial registers (XVIIIth century) were tapped. From hundreds of choreic records, unquestionable or dubious, genealogical trees, sometimes stretching along nine generations were built up. About fifty pedigrees gather the patients of four Belgian provinces (out of nine). The oldest and undeniable document was written in 1793. With this wealth in hand, we are able to corroborate or invalidate diagnosis of Huntington's chorea put forward by today psychiatrists and neurologists. The diagnostic blunders were not uncommon and, sometimes, funny. The geneticist comes often too late, post mortem, through archives. When he intervenes in due time, his advice is usually not successful with young adults, uninstructed and in love. The frequency of the disease is estimated around 1 in 10.000 births. The disappearance of old pedigrees and the dawn of new ones can be predicted. Our followers will observe it and, perhaps, be able to measure the frequency of mutation.     

Platelet factor XIII. The collagen receptor?

We have studied the binding of collagen fibers with platelet proteins using affinity chromatography on collagen-Sepharose. Only a few proteins from a platelet lysate were trapped by this column. When denatured collagen (gelatin) was used as the affinity ligand, the major protein did not bind and was identified as platelet Factor XIII by polyacrylamide gel electrophoresis, immunoprecipitation, and enzymic activity. This is a zymogen form of transglutaminase, which corresponds to the "a" subunit of the coagulation factor in plasma. Immunoglobulins specific for platelet Factor XIII obtained from antiserum raised against plasma Factor XIII were able to initiate platelet aggregation by themselves, in strong contrast to nonspecific antibodies. This specific immunoglobulin-mediated platelet aggregation required the presence of Ca2+. It was inhibited by aspirin and prostacyclin, but not by specific inhibitors for other agonists. These data suggest the possibility that the zymogen form of Factor XIII is located on the surface of platelets and may play a key role as the receptor for collagen-induced platelet aggregation.     

The identity of Polyalthia pingpienensis P. T. Li（Annonaceae）

An examination of the holotype of Polyalthia pingpienensis P. T. Li has shown that the holotype is an admixture. The branch and the flower on the sheet should be referred to P. plagioneura Diels,whereas the detached leaf belongs to another species,whose i     

Health Management with Reduced Antibiotic Use—The U.S. Experience

Since World War II the use of antimicrobial products associated with food animal production has increased. Antimicrobials along with evolving production practices have significantly increased throughput, animal welfare, and improved health. Concerns surrounding the growing significance of emerging and in some cases rapidly disseminating antibiotic (antimicrobial) resistant bacterial pathogens among human and livestock populations has stimulated a reassessment of this application. The negative publicity has led many consumers and activist groups to believe that protein derived from food animals grown in the absence of those drugs is safer than products derived from the conventionally reared. There is a general fear that antimicrobial usage in agriculture threatens the sustainability of human therapeutic agents and the public wellbeing. The issue has gradually emerged from “fringe group paranoia” to mainstream—finally impacting consumer choices.

Antimicrobial resistance concerns have stimulated a significant reaction by the US animal agriculture industry. Numerous pig production entities, large and small, have attempted to create additional pork product value by developing niche marketing opportunities. Thus far most of the subtherapeutic in-feed antimicrobial reduction has been voluntary in the US. Two production areas have developed where reduced usage occurs. First is the growth of antibiotic free production (ABF) and second is an increased use of treatment levels which avoids subtherapeutic criticism. The bulk of this article is directed at new production practices, pig health management, disease elimination, and biosecurity efforts that result from early industry attempts at reduced or excluded antimicrobial pig production. Raising antimicrobial (antibiotic) free (ABF) pork from birth is challenging for a variety of reasons. Some of these challenges can be cost effectively dealt with while others are difficult if not impossible to control in modern production environments. Healthy pig production is essential for sustainable ABF operations.     

The genius of E. E. metchnikoff— Discoveries over the centuries

On the 15 of May we celebrated the 150th anniversary of the outstanding Russian biologist Elias E. Metchnikoff (1845–1916)—Nobel Prize winner (1908), full and honorary member of many scientific academies of the world. His main works were applied to the zoology of invertebtates, evolution, embryology, immunology, microbiology, infectious pathology, gerontology, etc. Elias Metchnikoff published essays on anthropology, theory of orthobiosis, role of social and social-hygienic factors in solving the problems of old age and life elongation. On 30 May-2 June 1995 an International Symposium dedicated to Metchnikoff's 150th anniversary was held in Moscow. This is a text of the lecture given by us at the opening ceremony.     

The identity of Alpinia jianganfeng T.L.Wu（Zingiberaceae）

Alpinia jianganfeng T.L.Wu is conspecific with A.sichuanensis Z.Y. Zhu,and thus is reduced to synonymy.