Hybridization of mitochondrial and cytoplasmic ribosomal RNA with mitochondrial and nuclear DNA.

Hybridization assays of rat liver mitochondrial and cytoplasmic rRNAs with in vitro labelled mitochondrial and nuclear DNA were performed in liquid medium. Sensitivity towards S1 enzyme and Tms of the RNA-DNA hybrids were studied. Our results are in favour of a distinct genetic origin of the two types of cellular rRNAs.     

从近年科技投入变化看美国科技政策的变化

美国能够成为世界头号科技大国，其科技政策功不可没。近年来，美国不断调整其科技政策以保证站在世界的最前列，这可以从美国在科技中投入的不断变化看出来。本文基于冷战结束至今美国在科技中投入的变化，分析了美国科技政策十几年来的变化特点。     

Hybridization in the mexican and 13-lined ground squirrels,Spermophilus mexicanus andSpermophilus tridecemlineatus

Summary Evidence of hybridization between the ground squirrels,Spermophilus tridecemlineatus andS. mexicanus is presented on the basis of chromosomal and protein data. The hybrids produced appear to be completely interfertile. Based on the evidence of hybridization and the recent reestablishment of contact between these two species, they are considered to be semispecies.Supported by Faculty Research Grant No. 34925 from North Texas State University awarded toZimmerman.     

The insulin-degrading enzyme is an allosteric modulator of the 20S proteasome and a potential competitor of the 19S

The interaction of insulin-degrading enzyme (IDE) with the main intracellular proteasome assemblies (i.e, 30S, 26S and 20S) was analyzed by enzymatic activity, mass spectrometry and native gel electrophoresis. IDE was mainly detected in association with assemblies with at least one free 20S end and biochemical investigations suggest that IDE competes with the 19S in vitro. IDE directly binds the 20S and affects its proteolytic activities in a bimodal fashion, very similar in human and yeast 20S, inhibiting at (IDE)?≤?30 nM and activating at (IDE)?≥?30 nM. Only an activating effect is observed in a yeast mutant locked in the “open” conformation (i.e., the α-3ΔN 20S), envisaging a possible role of IDE as modulator of the 20S “open”–”closed” allosteric equilibrium. Protein–protein docking in silico proposes that the interaction between IDE and the 20S could involve the C-term helix of the 20S α-3 subunit which regulates the gate opening of the 20S.     

Abnormalities of meioses in male reciprocal hybrids between the Hiroshima and Ichinoseki populations ofRana japonica

In order to elucidate cytogenetically the cause of male sterility in intraspecific hybrids ofRana japonica, the behavior of chromosomes in the first meiosis was observed in spermatocytes from male reciprocal hybrids between two populations from Hiroshima and Ichinoseki. In the parental Hiroshima and Ichioseki populations, 2530 (96.7%) meiotic spreads had 13 bivalents and 78 (3.0%) contained 12 bivalents and two univalents, whereas in reciprocal hybrids only 337 (7.0%) contained 13 bivalents and the other 4445 (93.0%) had 2–26 univalents. A total of 31647 (93.4%) bivalents was ring-shaped and the other 2234 (6.6%) were rod-shaped in both parental populations, whereas in reciprocal hybrids 26352 (57.1%) and 19819 (42.9%) bivalents were ring- and rod-shaped, respectively. These results show that meiotic chromosomes of reciprocal hybrids are characterized by a remarkable increase in univalents and rod-shaped bivalents.     

美国气候变化技术计划(CCTP)新战略规划及其对我国的启示

美国气候变化技术计划(CCTP)于2006年9月公布了新的气候变化技术计划战略规划,新规划将通过捕集、减少以及储存的方式来控制温室气体的排放量。该计划中包含的技术有氢能源、生物提炼、清洁煤、碳储存、核分裂和聚变能等,这些技术以最基础的方式转化为国民经济价值,不仅能够改善气候变化,而且可以保证能源安全、空气污染以及其他紧迫需求。本文对美国气候变化技术计划战略规划的任务、目标、方法进行概要介绍,并论述了其对我国气候变化技术发展的重要启示。     

A new antisickling agent: In vitro studies of its effect on S/S erthrocytes and on hemoglobin S

Summary 2-{benzoylamino} pyridinium benzoate (BAPB) has exhibited an antisickling effect with homozygous S/S erythrocytes in vitro. This study suggests that BAPB prevents sicklin by inhibiting the gelation of hemoglobin S.Acknowledgments. This research has been partly funded by a Sickle Cell Research grant from the State of Tennessee to Meharry Medical College. We gratefully appreciate the technical assistance of Mr Rudolf Harlan and Mrs Marjorie Deveau of the School of Graduate Studies. We offer our thanks to Dr J. W. Davis, J. D., Coordinator, Sickle Cell Project, Meharry Medical College for constant encouragement.     

Why was M. S. Tswett’s chromatographic adsorption analysis rejected?

The present paper claims that M. S. Tswett’s chromatographic adsorption analysis, which today is a ubiquitous and instrumentally sophisticated chemical technique, was either ignored or outright rejected by chemists and botanists in the first three decades of the twentieth century because it did not make sense in terms of accepted chemical theory or practice. Evidence for this claim is culled from consideration of the botanical and chemical context of Tswett’s technique as well as an analysis of the protracted debate over Tswett’s chromatographic analysis of chlorophyll between him and Leon Marchlewski, a noted chlorophyll chemist of the period. In this way, the paper expands and amends what it calls the ‘textbook story’ of the early history of chromatography, examples of which may be found in historical notes in many textbooks of chemical instrumental analysis and numerous short articles in chemistry journals. The paper also provides an accessible introduction to the early history of chromatography for historians of science likely to know little or nothing about it.     

A new antisickling agent: in vitro studies of its effect on S/S erythrocytes and on hemoglobin S

2-(benzoylamino) pyridinium benzoate (BAPB) has exhibited an antisickling effect with homozygous S/S erythrocytes in vitro. This study suggests that BAPB prevents sickling by inhibiting the gelation of hemoglobin S.     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.).

112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms: Dipetalonema viteae, Fasciola hepatica; 3 of eggs: Ascaris suum, Toxocara canis, Schistosoma mansoni; and of Echinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

An improved thioflavine S method for staining neurofibrillary tangles and senile plaques in Alzheimer's disease.

Large differences are usually observed when standard staining methods for a number of pathological lesions in neurodegenerative disorders are compared. With the modified thioflavine S method presented here (easy and cheap to perform), the morphological appearance of the stained neurofibrillary tangles (NFT) and senile plaques (SP) is greatly improved. Furthermore, the intense contrast between stained lesions and background obtained with this technique permits an accurate automatic quantification of NFT and SP using a computer-assisted image analysis system.     

Increased contents of phenylethanolamine, m-octopamine and p-octopamine in the hypothalamus and brain stem of spontanously hypertensive rats (S.H.R. Kyoto)]

Phenylethanolamine, p-octopamine and m-octopamine contents were determined in the hypothalamus and the brain stem of spontaneously hypertensive Rats (S.H.R. Kyto) and the corresponding controls (Wistar Kyoto). In three-week-old Rats, phenylethanolamine and p-octopamine are found to be present in S.H.R. hypothalamus and brain stem at concentrations twice as high as compared to Wistar Kyoto Rats. The amount of m-octopamine is 5-fold higher in the brain stem of S.H.R. Rats as compared to Wistar Kyoto Rats.     

More letters by Paul Feyerabend to Thomas S. Kuhn on Proto-Structure

Four letters by Paul Feyerabend to Thomas Kuhn from the 1950s and 60s were found in Kuhn’s Nachlass at the Institute Archives and Special Collections of MIT. Two of them deal with topics that were at centre stage of the controversy between the two authors that was ignited by Feyerabend’s reading of Proto-Structure, the draft version of Kuhn’s The structure of scientific revolutions. These letters are reprinted here. They are probably the continuation of two letters by Paul Feyerabend to Thomas S. Kuhn formerly published in this journal (Hoyningen-Huene, 1995).     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.)

Summary 112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms:Dipetalonema viteae, Fasciola hepatica; 3 of eggs:Ascaris suum, Toxocara canis, Schistosoma mansoni; and ofEchinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

Thought styles and paradigms: A comparative study of Ludwik Fleck and Thomas S. Kuhn

At first glance there seem to be many similarities between Thomas S. Kuhn’s and Ludwik Fleck’s accounts of the development of scientific knowledge. Notably, both pay attention to the role played by the scientific community in the development of scientific knowledge. But putting first impressions aside, one can criticise some philosophers for being too hasty in their attempt to find supposed similarities in the works of the two men. Having acknowledged that Fleck anticipated some of Kuhn’s later theses, there seems to be a temptation in more recent research to equate both theories in important respects. Because of this approach, one has to deal with the problem of comparing the most notable technical terms of both philosophers, namely “thought style” and “paradigm”.This paper aims at a more thorough comparison between Ludwik Fleck’s concept of thought style and Thomas Kuhn’s concept of paradigm. Although some philosophers suggest that these two concepts are essentially equal in content, a closer examination reveals that this is not the case. This thesis of inequality will be defended in detail, also taking into account some of the alleged similarities which may be responsible for losing sight of the differences between these theories.     

Electrophoresis of the venom and haemolymph of the scorpionButhus Judaicus E. S.

Zusammenfassung Die elektrophoretische Analyse des Skorpiongiftes vonButhus judaicus E. S. ergab den Gehalt von mindestens 6 Proteinfraktionen. Drei dieser Fraktionen waren bei pH 8,6 von kathodischer Beweglichkeit und von offenbar höchster Toxizität. Davon völlig verschieden war das elektrophoretische Bild der Eiweisse in der Skorpionhämolymphe.     

Thought styles and paradigms—a comparative study of Ludwik Fleck and Thomas S. Kuhn

At first glance there seem to be many similarities between Thomas S. Kuhn’s and Ludwik Fleck’s accounts of the development of scientific knowledge. Notably, both pay attention to the role played by the scientific community in the development of scientific knowledge. But putting first impressions aside, one can criticise some philosophers for being too hasty in their attempt to find supposed similarities in the works of the two men. Having acknowledged that Fleck anticipated some of Kuhn’s later theses, there seems to be a temptation in more recent research to equate both theories in important respects. Because of this approach, one has to deal with the problem of comparing the most notable technical terms of both philosophers, namely “thought style” and “paradigm”.This paper aims at a more thorough comparison between Ludwik Fleck’s concept of thought style and Thomas Kuhn’s concept of paradigm. Although some philosophers suggest that these two concepts are essentially equal in content, a closer examination reveals that this is not the case. This thesis of inequality will be defended in detail, also taking into account some of the alleged similarities which may be responsible for losing sight of the differences between these theories.     

Nucleotide sequence of the gene for the mitochondrial 15S ribosomal RNA of yeast

We have determined the nucleotide sequence of a DNA segment carrying the entire 15S ribosomal RNA gene of yeast mitochondrial genome. Many stretches of sequence are present which are homologous to the E. coli 16S ribosomal RNA gene. The gene sequence can be folded into a secondary structure according to the [1] model on bacterial ribosomal RNAs. The structure reveals a striking similarity between the two RNAs despite the large difference in their base compositions. In the middle of the gene, we found a guanine-cytosine rich sequence that is also present in several other regions of the mitochondrial genome.     

Enhancement of the antitumor effect of illudin S by including it into liposomes.

Entrapping illudin S in liposome markedly enhanced life prolonging effect in ddN mice bearing Ehrlich ascites tumors, presumably by decreasing the side effects.     

How accurate are the U.S. Bureau of the Census projections of total live births

"The accuracy of total live birth forecasts issued by the U.S. Bureau of the Census was analysed. Forecast accuracy has not improved significantly since 1950. Further, the forecasts are not more accurate than several naive alternatives. Moving from a period methodology to a cohort methodology improved forecast accuracy for certain forecasts. [It is demonstrated that] the Bureau of the Census systematically underestimated total births in the upswing and overestimated in the downswing."