The electron-microscopic structure of nucleoprotein fibrils from metaphase chromosomes treated with salt

The diameter of nucleoprotein fibres of metaphase chromosomes is sensitive to salt concentrations. Treatment of human lymphocyte cells in metaphase with a hypotonic medium and spreading them on a water surface causes swelling of the chromosome fibres from 150–180 Å to 230–250 Å. Treatment of the chromosomes with 0.15–0.45 M NaCl, a concentration at which histones are not yet removed from the nucleoprotein complexes, apparently does not affect the chromosome structure. Treatment with NaCl solutions between 0.6 M and 2.0 M NaCl leads to a progressive extraction of the chromosomal proteins and decreases the diameter of the chromosome fibres to 80–100 Å and less.Dedicated to Prof. Dr. A. Butenandt on the occasion of his 70th birthday.     

On the requirement of minimum number of four versus eight quanta of light for the evolution of one molecule of oxygen in photosynthesis: A historical note

A bitter controversy had existed as to the minimum number of quanta required for the evolution of one molecule of oxygen in photosynthesis: Otto Warburg had insisted since 1923 that this value was 3–4, whereas Robert Emerson and others continued to obtain a value of 8–12 since the 1940s. It is shown in this letter that the 1931 Nobel-laureate of Physiology & Medicine Otto Warburg published, in his last and final paper, just before his death in 1970, a measured minimum quantum requirement of oxygen evolution of 12 at the lowest intensities of light he used. Although using his theory on photolyte, Warburg calculated a value of 3–4 for the quantum requirement, this is the first confirmation by Warburg of the higher measured quantum requirement. However, it has remained unknown to most investigators. It is expected that this information will be of general interest not only to those interested in the history and research on photosynthesis, but to the entire sci entific community, especially the writers of text books in biology, biochemistry and biophysics.     

Helping Science and Drug Development to Succeed through Pharma-Academia Partnerships: Yale Healthcare Conference 2013

The theme of the 2013 Yale Healthcare Conference was “Partnerships in Healthcare: Cultivating Collaborative Solutions.” The April conference brought together leaders across several sectors of health care, including academic research, pharmaceuticals, information technology, policy, and life sciences investing. In particular, the breakout session titled “Taking R&D Back to School: The Rise of Pharma-Academia Alliances” centered on the partnerships between academic institutions and pharmaceutical companies. Attendees of the session included members of the pharmaceutical industry, academic researchers, and physicians, as well as graduate and professional students. The discussion was led by Dr. Thomas Lynch of Yale University. Several topics emerged from the discussion, including resources for scientific discovery and the management of competing interests in collaborations between academia and the pharmaceutical industry.     

‘The vagaries of a Rafinesque’: imagining and classifying American nature

Some early nineteenth-century American naturalists condemned their contemporary, Constantine Samuel Rafinesque (1783–1840), as ‘eccentric’, or worse. Both during his life and long after his death, his botanical work in particular was criticised, even ridiculed. However, in recent years, attempts have been made to restore his reputation and the term ‘genius’ has even been used to describe him. This paper examines this continuing fascination with this strange, disturbing figure and argues that in the competing interpretations of his life and work, Rafinesque has generally been used to typify bad classification; he is perhaps better understood in a broader, literary context as embodying a particular kind of American national identity.     

One hundred years of Polish rotiferology — scientists and their work

Polish scientific publications concerning rotifers are recorded and discussed. They contain about 320 papers published in 1947–1993, and about 120 papers for the period 1758–1939, listed by Harring in his Synopsis (1913) and later by Wiszniewski (1954). The papers of Wierzejski (published mainly in 1893) mark a century of advanced rotifer studies in Poland. The work of Wiszniewski on psammon (published in 1933–1938) and on parasitic rotifers (1939, 1948, 1953) is presented in detail, as well as the papers of Pawlowski (published in 1934–1980). A number of contemporary Polish rotifer publications and their distribution by habitat studied, as well as selected results, are discussed.     

Lichens show that fungi can acclimate their respiration to seasonal changes in temperature

Five species of lichens, the majority members of a soil-crust community (Cladonia convoluta, Diploschistes muscorum, Fulgensia fulgens, Lecanora muralis, Squamarina lentigera) showed seasonal changes of temperature sensitivity of their dark respiration (DR) to such an extent that several substantially met the definition of full acclimation, i.e. near identical DR under different nocturnal temperature conditions during the course of the year. C. convoluta, for example, had maximal DR at 5°C of –0.42, –1.11 and –0.09 nmol CO₂ g^–1 s^–1 in autumn, winter, and summer, respectively, a tenfold range. However, at the mean night temperatures for the same three seasons, 9.7°C, 4.2°C and 13.6°C, maximal DR were almost identical at –1.11, –0.93, and –1.45 nmol CO₂ g^–1 s^–1. The information was extracted from measurements using automatic cuvettes that continuously recorded a sample lichens gas exchange every 30 min under near-natural conditions. The longest period (for L. muralis) covered 15 months and 22,000 data sets whilst, for the other species studied, data blocks were available throughout the calendar year. The acclimation of DR means that maximal net carbon fixation rates remain substantially similar throughout the year and are not depressed by increased carbon loss by respiration in warmer seasons. This is especially important for lichens because of their normally high rate of DR compared to net photosynthesis. We suggest that lichens, especially soil-crust species, could be a suitable model for fungi generally, a group of organisms for which little is known about temperature acclimation because of the great difficulty in separating the organism from its growth medium. Fungi, whether saprophytic, symbiotic or parasitic, including soil lichens, are important components of soil ecosystems and contribute much of the respired CO₂ from these systems. Temperature acclimation by fungi would mean that expected increases in carbon losses caused by global climate warming from soil ecosystems might not be as extensive as first thought. This would ameliorate this positive feedback loop present in some climate models and might substantially lower the predicted warming.This work is dedicated to Professor Hubert Ziegler on the occasion of his 80th birthday. We would like to acknowledge his impressive contribution to physiological plant ecology, and to wish him continuing joie de vivre with his scientific interests during a happy retirement.     

Amino acid auxotrophs from protoplast cultures of Nicotiana plumbaginifolia, Viviani

Summary Several amino acid requiring auxotrophs have been isolated from unsupplemented protoplast cultures of haploid Nicotiana plumbaginifolia following incubation with BUdR (1-5x10^-5, 2 days) and recovery on complete medium. The auxotrophic lines required the following amino acid(s) for growth: his, ile, leu, ile+val, met or try. Met^– is a new type isolated in higher plants. The same absolute amino acid requirement was observed in plants regenerated from auxotrophic cultures. Precursor feeding tests, enzyme assays, and/or metabolic complementation through protoplast fusion were used to identify the genetic lesion leading to auxotrophy. Mutant seeds were obtained from supplemented Met^– plants. Seeds were also collected from selfed plants regenerated from various complementing fusion products, and a His^– revertant. Genetic analysis indicated that under natural conditions of seed formation amino acid auxotrophy-in contrast to NR deficiency-failed to segregate in progeny tests.Abbreviations and definitions BUdR and FUdR 5-bromo- and fluoro-deoxyuridine respectively - AP imidazole acetol phosphate - IGP imidazole glycerol phosphate - NR nitrate reductase - NAA naphthaleneacetic acid - BAP 6-benzylaminopurine - TIP total isolation procedure - ER Escape rate—the proportion of the selected cell population surviving the BUdR treatment - BR Recovery rate—the proportion of clones identified as amino acid auxotrophs from total escaping clones - TS Total surviving colonies—the number of inoculated protoplasts/variant x plating efficiency - TST Total starvation time—the number of days on minimal medium (preincubation time+BUdR incubation time). The relationship days vs. number of divisions is as follows: 3- to 4-day-old protoplasts, 1 division; 5–6 days, 2 divisions; 7–8 days, 3 divisions Dedicated to Professor Georg Melchers to celebrate his 50-year association with the journal     

Determination of disulfide bond arrangement in bombyxin-IV, an insulin superfamily peptide from the silkworm,Bombyx mori, by combination of thermolysin digestion of natural peptide and selective synthesis of disulfide bond isomers

The mode of disulfide linkages in bombyxin-IV, an insulin superfamily peptide consisting of A- and B-chains, was determined as A6–A11, A7–B10, and A20–B22. An intermolecular bond of A20–B22 was identified by sequencing and mass spectrometric analysis of the fragments generated by thermolysin digestion of natural bombyxin-IV. The mode of the remaining two bridges was determined by chemical and selective synthesis of three possible disulfide bond isomers of bombyxin-IV. A- and B-chains were synthesized by solid-phase method, and three disulfide bonds were bridged stepwise and in a fully controlled manner. Retention time on reversed-phase high-performance liquid chromatography (HPLC), thermolysin digests, and biological activity of the synthetic [A6–A11, A7–B10, A20–B22-cystine]-bombyxin-IV revealed that it was identical with the natural bombyxin-IV. Two other isomers with respect to disulfide bond arrangement, [A6–A7, A11–B10, A20–B22-cystine]- and [A6–B10, A7–A11, A20–B22-cystine]-bombyxin-IVs, were distinguishable from the natural one by use of HPLC, thermolysin digestion, and bioassay.     

Enrico Ferri’s Scientific Socialism: A Marxist Interpretation of Herbert Spencer’s Organic Analogy

Spencer’s evolutionary philosophy is usually identified with right-wing doctrines such as individualism, laissez-faire liberalism and even conservatism. Since he himself defended similar positions, it is perhaps not surprising that the study of the political interpretations of his ideas has drawn relatively little attention. In this article I propose to examine a rather atypical reading of Spencer’s organic analogy, though definitely not a marginal one: Enrico Ferri’s Marxist doctrine of Scientific Socialism. Ferri is not a figure unknown to scholars interested in the political aspects of the evolutionary debate. Nonetheless, the relation between his theory and Spencer’s bio-sociology – notably the complex dialectic of themes such as “the struggle for existence” versus “class struggle,” or “evolution” versus “revolution” – has not yet received full-length analysis. In my study I investigate the diffusion of Spencer’s ideas in Italy and their impact on the new “positivist” sciences of psychology and sociology inasmuch as these questions are essential to understanding Ferri’s position. Throughout, I stress the importance of the intellectual and political context in the process of appropriation of ideas that led to this unexpected shift in meaning.¹ Spencer, 1843, 1851, 1879–1893, 1884.     

Reexamination of paternal age effect in Down's syndrome

Summary Paternal age distribution for 1279 cases of Down's syndrome born in 1952–1968 was compared with the corresponding distribution for the general population, corrected for the maternal age as well as for the year of birth of the patients. Although there was no difference in the mean paternal age, the two distributions differed significantly, largely due to the excess of fathers aged 55 years and over and to the deficit of those aged 40–44 years in the patients born to mothers aged 30 years and over. The overall pattern of the relative incidence of Down's syndrome with advancing paternal age, with maternal age controlled, seems consistent with the hypothesis proposed by Stene et al. (1977). It increased from 0.8 for fathers aged 20–24 years slowly up to 1.2 for those aged 45–49 years, though with an intermediate drop to 0.8 at the age of 40–44 years, and then sharply to 2.4 for those aged 55 years and over. This rising pattern of the relative incidence with paternal age was essentially the same for the patients born in 1952–1960 and for those born in 1961–1968, although the slope was less steep in the latter than in the former group.This paper is dedicated to Professor Heinrich Schade in honor of his 70th birthday     

Duty or dream? Edwin G. Conklin's critique of eugenics and support for American individualism

This paper assesses ideas about moral andreproductive duty in American eugenics duringthe early twentieth century. While extremeeugenicists, including Charles Davenport andPaul Popenoe, argued that social leaders andbiologists must work to prevent individuals whowere ``unfit' from reproducing, moderates,especially Edwin G. Conklin, presented adifferent view. Although he was sympathetic toeugenic goals and participated in eugenicorganizations throughout his life, Conklinrealized that eugenic ideas rarely could meetstrict scientific standards of proof. Withthis in mind, he did not restrict his eugenicvision to hereditary measures. Relying onhis experience as an embryologist, Conklininstead attempted to balance more extremeeugenic claims – that emphasized the absolutelimits posed by heredity – with his own view of``the possibilities of development.' Throughhis critique he argued that most human beingsnever even begin to approach their hereditarypotential; he moderated his own eugenicrhetoric so that it preserved individualopportunity and responsibility, or what hasoften been labeled the American Dream.     

Thiocapsa halophila sp. nov., a new halophilic phototrophic purple sulfur bacterium

A new phototrophic sulfur bacterium has been isolated from a red layer in a laminated mat occurring underneath a gypsum crust in the mediterranean salterns of Salin-de-Giraud (Camargue, France). Single cells were coccus-shaped, non motile, without gas vacuoles and contained sulfur globules. Bacteriochlorophyll a and okenone were present as major photosynthetic pigments. These properties and the G+C content of DNA (65.9–66.6 mol% G+C) are typical characteristics of the genus Thiocapsa. However, the new isolate differs from known species in the genus, particularly in NaCl requirement (optimum, 7% NaCl; range, 3–20% NaCl) and some physiological characteristics. Therefore, a new species is proposed, Thiocapsa halophila, sp. nov.Dedicated to Prof. Dr. Norbert Pfennig in occasion of his 65th birthday     

The First Successful Prenatal Diagnosis on a Korean Family with Citrullinemia

DNA prenatal diagnosis was successfully performed on a family with citrullinemia. The father carried the G324S mutation and the mother carried the IVS6–2A > G mutation in the argininosuccinate synthase gene. They had a previous child with citrullinemia who died in the week after birth owing to complicated hyperammonemia. The lost child turned out to be a compound heterozygote. DNA was extracted from the cultured amniotic cells after amniocentesis done at 18-week gestation. For the detection of the G324S mutation, the PCR and restriction fragment length polymorphism method was used, and for the IVS6–2A > G mutation, allele-specific PCR was performed. The fetus was found to carry G324S but not IVS6–2A > G, suggesting a heterozygote carrier. Pregnancy was continued and a healthy boy was born. Plasma amino acid analysis performed on the third day after birth was normal and the serial ammonia level was in the normal range. A molecular study on his genomic DNA after birth also agreed with the previous fetal DNA analysis. He is now 2-months old with normal growth and development.     

It's a Wonderful Life: A Career as an Academic Scientist

Many years of training are required to obtain a job as an academic scientist. Is this investment of time and effort worthwhile? My answer is a resounding “yes.” Academic scientists enjoy tremendous freedom in choosing their research and career path, experience unusual camaraderie in their lab, school, and international community, and can contribute to and enjoy being part of this historical era of biological discovery. In this essay, I further elaborate by listing my top ten reasons why an academic job is a desirable career for young people who are interested in the life sciences.Students are attracted to careers in academic science because of their interest in the subject rather than for financial reward. But then they hear messages that make them think twice about this career choice. It is difficult to find a job: “Hear about Joe? Three publications as a postdoc and still no job offers.” The NIH pay line is low: “Poor Patricia, she is now on her third submission of her first NIH grant.” Publishing is painful: “Felix''s grad school thesis work has been rejected by three journals!” Academic jobs are demanding: “Cathy has spent her last three weekends writing grants rather than being with her family.”Such scenarios do take place, but if you think that this is what a career in academic science is about, then you need to hear the other side of the story. And this is the purpose of this article—a chance to reflect on the many good things about the academic profession. In the classic movie It''s a Wonderful Life, George Bailey is at the point of despair but regains his confidence through the wisdom and perspective of a guardian angel, Clarence. Doubt and setbacks also are bound to happen in science (as is true of other careers), but pessimism should not rule the day. It is a great profession and there are many happy endings. I would like to share my top ten reasons of why being an academic professor is a “wonderful life,” one that bright and motivated young people should continue to aspire to pursue.     

Specific receptor input into spectral preference inDrosophila

Summary Drosophila have 3 types of retinal receptors, R1–6, R7 and R8. Using visual mutant strains lacking function in one or two receptor types, spectral preference in walking fast (30 s) phototaxis was measured. High correlations for intensity-response functions were obtained (Fig. 2 and 5). With a 467 nm choice standard, which could saturate R1–6, white-eyed strains with only R8 or with R1–6 plus R8 functional exhibited similar spectral sensitivities with a broad peak at visible wavelengths (Fig. 3) not unlike the electrophysiological characterization of R8 (Fig. 1). Strains with R7 plus R8 or with all receptors intact exhibited similar functions with a high ultraviolet (UV) peak (Fig. 4), like the electrophysiological characterization of R7 plus R8. The presence of R1–6 did not alter the profiles mediated by R8 alone or by R7 plus R8.With a 572 nm standard, which should maintain R1–6 function, white- and red-eyed wild-type strains with all receptors intact exhibited similar UV dominated spectral sensitivities, probably from R7 plus R8, with weak visible secondary peaks possibly from R1–6 or R8 (Fig. 6). However, even with a very dim 572 nm standard or with no standard at all, unequivocal evidence for R1–6 input was not found and intensity-response function correlations were low. This finding and other recent studies suggest that specific phototactic or optomotor tasks and conditions (e.g., adaptation level) determine the extent to which each receptor input is utilized.Spectral preference with a bright 365 nm standard was difficult to measure because of the strong UV preference in phototaxis. In pilot studies, an ocelliless strain showed strong fast phototaxis.Supported by NSF grants BMS-74-12817 and BNS-76-11921. We thank D. Lakin, A. Ivanyshyn, R. Greenberg, M. Chapin, D. Fritzberg, and W. Hamilton for technical assistance. We also thank R. Schümperli for suggestions, for his permission to redraw his data and for confirming the conversions we made.     

Spontane und chloramphenicolinduzierte Chromosomenmutationen und biochemische Befunde bei zwei Fällen mit Glutathionreduktasemangel (NAD(P)H: Glutathione oxidoreductase,E.C. 1.6.4.2.)

Summary In one proband with pancytopenia and in his mother with normal blood picture the pattern of the erythrocyte enzymes revealed a glutathione reductase deficiency with a missing GR-II-band in the electropherogram. The incidence of spontaneous aberrations in the chromosomes of both individuals (52–58% and 7.2–8% metaphases with chromosomal damage) was significantly higher than in normal controls (0–3%). After 0.5 mg chloramphenicol per ml culture medium was applied 24 hours before fixation the number of damaged metaphases further increased to about 81% and 19–21%, respectively. Possible reasons for this phenomenon are discussed.     

Membrane-bound enzymes and their role in processing of the dynorphins and of the proenkephalin octapeptide Met-enkephalin-Arg-Gly-Leu

Synaptosomal membrane (SPM) bound exo- and endopeptidases cleave the dynorphins and Met-enkephalin-Arg-Gly-Leu at several sites to produce shorter fragments; among these are dynorphin 1–8 from 1–17, and Met-enkephalin from Metenkephalin-Agr-Gly-Leu. the most vulnerable site is the Tyr-Gly bond cleaved by membrane-bound aminopeptidase(s), with the shorter peptides degraded more rapidly than the longer ones. A purified metalloendopeptidase sensitive to phosphoramidon inactivates the shorter peptide sequences at the Gly³-Phe⁴ bond, and the 1–13 and 1–17 sequences also at the Arg⁷-Ile⁸ bond. The k_cat/K_m ratios for purified metalloendopeptidase were 20–30 times higher for Leu-enkephalin and the proenkephalin octapeptide than for dynorphins 1–8, 1–13, and 1–17. Dynorphins 1–13 and 1–17 may serve as precursors for the widely distributed CNS neuropeptide dynorphin 1–8 since they were cleaved by a separate SPM endopeptidase insensitive to phosphoramidon. SPM monocarboxypeptidase converted dynorphin 1–13 to 1–12 (release of Lys) and dipeptidyl carboxypeptidase converted dynorphin 1–8 to 1–6; enkephalin octapeptide served as a precursor of Met-enkephalin by sequential action (release of Leu and Arg-Gly) of both carboxypeptidases.Dedicated to Henry McIlwain.     

Influence of nitrogen deficiency on biochemical composition of the green alga <Emphasis Type="Italic">Botryococcus</Emphasis>

A study has been carried out to investigate the influence of nitrogen deficiency on intracellular lipid composition, including total fatty acid composition of lipids, polar lipids, and triacylglycerols, of the alga Botryococcus braunii Kütz IPPAS H-252 in batch culture. Under nitrogen limitation, the alga accumulates lipids as triacylglycerols and the total fatty acid (FA) composition changes: trienoic acids decrease (from 52.8–57.2 to 19.5–24.7% of the total FAs) and the oleic acid increases (from 1.1–1.2 to 17.1–24.4%) as does the saturated acids (from 23.7–26 to 32.9–46.1%). A similar rearrangement in the FA spectrum occurs at later times in the control culture, but it is less pronounced. Under nitrogen limitation, considerable changes in the polar lipid FAs are registered at day 13: saturated acids increase (from 28.6–35.5 to 76.8%) and all polyenoic acids markedly decrease (from 56.9–64.1 to 6.8%). Changes in the triacylglycerol fatty acid spectrum are seen on day 7: the oleic acid increases (from 14.7 to 34.2%) and remains at a high level till the end of the culture. In the control, triacylglycerols with large contents of oleic acid are detected at day 13, the total lipids and triacylglycerols still remaining unchanged.     

A novel EDTA-degrading Pseudomonas sp.

A bacterial strain LPM-410 capable of utilizing ethylenediaminetetraacetate (EDTA) as the sole source of energy, carbon, and nitrogen was isolated from sewage sludge and identified as a Pseudomonas sp. on the basis of its phenotypic characteristics. Suspensions of exponential-phase cells degraded EDTA, Mg–, Ca–, Ba–, and Mn–EDTA at constant specific rates ranging from 0.363 to 0.525 mmol EDTA/(g cells h). The more stable chelate, Zn–EDTA, was degraded at a lower rate (0.195 ± 0.030 mmol EDTA/(g cells h)), and here was no degradation of Co–, Cu–, Pb–, and Fe(III)–EDTA.