Natural products discovery from micro-organisms in the post-genome era†

With the decision to award the Nobel Prize in Physiology or Medicine to Drs. S. ōmura, W.C. Campbell, and Y. Tu, the importance and usefulness of natural drug discovery and development have been revalidated. Since the end of the twentieth century, many genome analyses of organisms have been conducted, and accordingly, numerous microbial genomes have been decoded. In particular, genomic studies of actinomycetes, micro-organisms that readily produce natural products, led to the discovery of biosynthetic gene clusters responsible for producing natural products. New explorations for natural products through a comprehensive approach combining genomic information with conventional methods show great promise for the discovery of new natural products and even systematic generation of unnaturally occurring compounds.     

The discovery of aniline and the origin of the term “aniline dye”

An historical background is provided for the term, “aniline dye,” which is still widely used as a synonym for “synthetic dye.” The discovery of aniline and the role of Hofmann in clarifying it are described. The subsequent discovery of mauveine (mauve) by a student of Hofmann's, William Perkin, and his difficulties in transforming an academic synthesis into a commercial product also are discussed. The key role of Scottish dyers, the Pullars of Perth and Thomas Keith in London, in this technology transfer is described. The subsequent ascendancy of the German dyestuff industry over British manufacturers is noted.     

Update on the laboratory diagnosis and monitoring of HIV infection

In China, the estimated number of HIV infected cases is approaching one million. Although public education has been initiated for awareness and behavioral modification for this devastating infection, better diagnostic methods are needed to identify infected persons and manage infection. Simple and more accurate diagnostic tools have become available, particularly for early detection and to monitor treatment in those who receive anti-retroviral treatment. In this short review, we summarize some of the common and new methodologies that can be used in clinical laboratories, in the field, or in private laboratories. These range from simple antibody tests to more sophistical methods that are used to monitor disease progression and identify drug resistance. These tools can assist physicians, medical practitioners, and laboratory personnel to select suitable diagnostic tools for the diagnosis, blood screening, monitoring of disease progression, and for detection of drug resistance to anti-retroviral therapies.     

Accomplishments of the Trustees and laboratory staff of the Biological Stain Commission, 2002–2013

During the 12 years from 2002 to 2013, the Trustees and laboratory personnel of the Biological Stain Commission (BSC) can claim many accomplishments. These accomplishments are itemized under 11 categories: continuous publication of the official journal, Biotechnic & Histochemistry; production of four special issues of Biotechnic & Histochemistry devoted to specific dyes or stains; standardization of staining and dye purity; mechanisms of staining and prediction of dye behavior; publication of books or book chapters; effects of fixation and processing on staining; cancer research; immunohistochemistry; BSC Laboratory activities; miscellaneous publications; and administrative accomplishments.     

Short-term feeding of Temora longicornis Müller in the laboratory and the field

Short-term feeding (min to h) of the copepod Temora longicomis (Müller) was investigated in the laboratory and in the field by monitoring the increase in gut fluorescence of adult females. Laboratory feeding studies using the diatoms Thalassiosira pseudonana (Hust.), T. weissflogii (Hust.) and Ditylumbrightwellii (West) showed that ingestion rates increased with increased food concentration and cell size. The maximum ingestion rate was 9.5 ng chl. equiv. female ⁻¹. h ⁻¹ on a diet D. brightwellii. Clearance rates decreased with increased food concentration and decreased cell size. Maximum clearance rate was 1.9 ml. female⁻¹·h⁻¹ also on a diet of D. brightwellii. On two of three occasions, ingestion and clearance rates in the field were twice as high at night as during the day. Night rates were similar to laboratory rates in the chlorophyll range found in the field. Diel differences in feeding activity in the field appeared to have been behaviorally induced rather than being related to vertical migration of individuals into food rich layers.     

Phenotypic screening meets natural products in drug discovery†

The Nobel Prize in Physiology or Medicine 2015 was awarded for discoveries related to the control of parasitic diseases using natural products of microbial and plant origin. In current drug discovery programs, synthesized compounds are widely used as a screening source; however, this award reminds us of the importance of natural products. Here, we introduce our phenotypic screening methods based on changes in cell morphology and discuss their effectiveness and impact for natural products in drug discovery.     

Looking back on the discovery of α-bungarotoxin

This review is a personal narration by a retiring pharmacologist from Taiwan who looks back at his discovery of -bungarotoxin from the historical perspective of Taiwan during the last 50 years, with accounts of his experiences and his efforts to overcome hardship. How the -toxin was isolated and characterized as an irreversible specific nicotinic acetylcholine (ACh) receptor antagonist,and how it subsequently became a useful experimental probe are presented here. The dilemma of differentiating the actions of tubocurarine and -bungarotoxin is analyzed. The author also outlines findings based on work done in his laboratory using -bungarotoxin as a tool on particular aspects of synaptic transmission. These include presynaptic receptor for positive feedback of transmitter release, explosive release of ACh, up- and down-regulation of ACh receptors after chronic drug treatment, autodesensitization of junctional ACh receptors, differences in action between natural transmitter and exogenous agonists and that between junctional and extra-junctional ACh receptors. Some experimental pitfalls, in which biomedical scientists are frequently trapped, are raised. Finally, some anecdotes are appended from which the reader may further understand scientific life in the 20th century, including its joys and regrets.     

Isopoly-L-ornithine Derivatives of Thymine and Thymidine†

Abstract

L-Ornithine derivatives of thymine, and thymidine gave oligomers by solid phase elongation reactions. These oligomers 2 and 3, however, hardly interact with the complementary polynucleotide. Conformational studies of the oligomers with CD and NMR revealed that stable intramolecular hydrogen bonding was formed between thymine base and ornithine unit.

     

Antibacterial discovery and development--the failure of success?

A combination of approaches and compounds-many of which failed to yield immediate results in the past-will ultimately prove invaluable to the drug industry in the ongoing battle against infectious disease.     

Pursuing the unlimited potential of microorganisms—progress and prospect of a fermentation company†

Production of pharmaceuticals and chemicals using microbial functions has bestowed numerous benefits onto society. The Nobel Prize awarded to Professor ōmura, Distinguished Emeritus Professor of Kitasato University, showed the world the importance of the discovery and practical application of microorganisms. Now, increasing attention is turned toward the future path of this field. As people involved in the microorganism industry, we will review the industrial activities thus far and consider the possible future developments in this field and its potential contribution to society.     

Sequential Binding of Staphylococcal y-Hemolysin to Human Erythrocytes and Complex Formation of the Hemolysin on the Cell Surface†

Staphylococcal γ-hemolysin consists of two protein components, F (or HγI) and HγII. To elucidate the mode of action of γ-hemolysin, we studied the binding order of F and HγII to human erythrocytes and the cell-bound state of the two components. The binding of F to human erythrocytes preceded the binding of HγII to the cells, and thereafter hemolysis occurred. Western immunoblot analysis of the cell-bound γ-hemolysin indicated that F and HγII components form high-molecular-mass (150–250 kDa) complexes on the erythrocytes. The toxin complexes were recovered in a Triton X-100-insoluble fraction of the erythrocytes, which contains cytoskeleton proteins. Neither the formation of the toxin complex(es) nor hemolysis occurred when the erythrocytes were treated with proteinase K. Abortion of the complex formation on the proteinase K-treated erythrocytes may be due to the failure of the binding of HγII to the cells, because F bound to the proteinase K-treated erythrocytes to the same extent as to the non-treated erythrocytes.     

A multivalent approach to the discovery of long-acting β(2)-adrenoceptor agonists for the treatment of asthma and COPD

A multivalent approach was applied to the design of long-acting inhaled β(2)-adrenoceptor agonists. A series of dimeric arylethanolamines based on the short acting β(2)-adrenoceptor agonist albuterol were prepared, varying the nature and length of the linker between the basic nitrogens. None of the C(2)-symmetric dimers demonstrated increased potency, however dimer 5j, derived from 4-phenethylamine, was found to have increased binding potency in vitro relative to the parent monomer. Optimization of this structure led to the identification of 22 (milveterol) which demonstrates high potency in vitro and long duration of action in a guinea pig model of bronchoprotection.     

Studies on the Cell Wall of Piricularia oryzae†

The chemical constituents of the cell wall of Piricularia oryzae, the pathogenic fungus of rice blast disease, were studied with the aids of chemical analysis, X-ray diffraction, infra-red absorption and enzymatic degradation. The sugar constituents were identified by chromatography as glucose (62%), mannose (4%), galactose (0.5%), and hexosamine (13%). The acidic amino acid rich protein was comprised 4.6% in the cell wall. The cell wall consists of at least three different polysaccharide complexes: a) α-Heteropolysaccharide protein complex containing mannose, glucose and galactose, b) β-1,3-Glucan containing β-1, 6-linked branch, c) Chitin like substance.     

An historical perspective of the discovery of titin filaments –Part 2

In 2017, a Special Issue of Biophysical Reviews was devoted to “Titin and Its Binding Partners. The issue contained a review: “An historical perspective of the discovery of titin filaments” by dos Remedios and Gilmour that was intended to be a history of the discovery of the giant protein titin, previously named connectin. The review took readers back to the earliest discovery of the so-called third filament component of skeletal and cardiac muscle sarcomeres and ended in 1969. Recently, my colleague Shin’ichi Ishiwata gently reminded me of two papers published in 1990 and 1993 that were unwittingly omitted from the original historical perspective. In the first paper (J Cell Biol 110:53–62, 1990), Funatsu et al. examined the elastic filaments in skeletal muscle using a combination of light and electron microscopy, but they also measured resting as well as passive stiffness mechanical measurements to establish that connectin (titin) is responsible for both stiffness and fiber tension. In the second paper (J Cell Biol 120:711–724, 1993), Funatsu et al. used permeabilised cardiac muscle myocytes (from rabbit papillary muscles) and focussed on filament ultrastructure using either freeze-substitution or deep-etched replica methods to visualise connectin/titin filaments in fibers with and without actin and myosin filaments.