Cordycepin A New Antibiotic

A strain of the mould Cordyceps militaris (Linn.) Link has been promoted on nitrogenous media to yield solutions which inhibit the growth of several microorganisms. It has been shown that the total activity of the solutions can be absorbed upon activated charcoal from which the active principle, cordycepin, has been isolated. Dilute aqueous solutions of cordycepin reproduce the Inhibitory effect of the culture solutions towards the test organism, and the activity is sufficiently great to term cordycepin an antibiotic. The metabolic product contains the elements carbon, hydrogen, oxygen and nitrogen and is optically active. It forms salts with picric acid, picrolonic acid and flavianic acid, and elemental analyses of the metabolic product and its simple derivatives suggested the empirical formula C8H10O2N4 or C10H13O3N5. The solubility properties of cordycepin are such that a standard method of molecular weight determination could not readily be employed to distinguish between these alternatives; an accurate micro-method for the molecular weight determination of bases such as cordycepin was therefore devised and is discussed in the Appendix. The molecular weight of cordycepin was found to be 254, in close agreement with that required by C10H13O3N5 (251). The first indication of the structure of the metabolic product was obtained from a study of its ultraviolet light absorption which shows marked similarity to that of some pyrimidine and purine compounds. Cordycepin is resistant to reduction and hydrogenation, but benzoylation yielded a tetrabenzoate and from the acid hydrolysis of this ester, adenine hydrochloride was isolated, thus accounting for the total nitrogen content of the molecule. The metabolic product itself was found to be unstable in dilute hydrochloric acid, hydrolysis occurring to yield solutions from which adenine was isolated and characterised as its picrate. Solutions of hydrolysed cordycepin have been shown to react with 2:4-dinitrophenylhydrazine in hydroohlorio acid, yielding the 2:4-dinitrophenylosazone of a molecule C5H10O4 and this suggests that the linkage between adenine and the residual fragment Is glycosidic rather than amide. No carbon-methyl, methoxyl or nitrogen-methyl group was detected in cordycepin, and the absence of the grouping CH3.CHOH or CH3.CO in the side chain was confirmed by the negative result of the iodoform test, but the presence of a terminal hydroxymethyl group was proven by the tosylation of cordycepin. Deamination of cordycepin yielded hypoxanthine, proving the molecule to be unsubstituted on the 6-amino group of the adenine nucleus. The glycosidic bond therefore occurs at the 7- or 9-position and the formulation of cordycepin as an adenine-9-glyooside is much preferred on the basis of the ultraviolet absorption spectrum. Since an osazone of the glycosidic fragment has been isolated corresponding to a deoxypentose (cordycepose), cordycepin cannot be an adenine-9:2'-deoxypentoside; evidenoe that the molecule is an adenine-9:3'-deoxypentoside has been provided by the fact that cordycepin is resistant to periodate oxidation. Careful hydrolysis of cordycepin followed by removal of adenine and hydrochloric acid yielded analytically pure cordycepose as a pale straw-coloured syrup which reduces Fehling's solution; bromine oxidation of the sugar gave the corresponding lactone, cordyceponolactone, C5H8O4. The latter yields a crystalline phenylhydrazide and cordycepose must be a deoxyaldopentose. The four stereoisomeric phenylhydrazides corresponding to a straight-chain 3-deoxyaldopentonic acid have been described previously, and differ markedly in physical properties from cordyceponic acid phenylhydrazide. Cordycepose is therefore a branch-Chain sugar, and this theory is strongly supported by the fact that no optical activity could be detected in ethanolic solutions of cordycepose p-bromophenylosazone. (Abstract shortened by ProQuest.)

Extending bicluster analysis to annotate unclassified ORFs and predict novel functional modules using expression data

<p>Abstract</p> <p>Background</p> <p>Microarrays have the capacity to measure the expressions of thousands of genes in parallel over many experimental samples. The unsupervised classification technique of bicluster analysis has been employed previously to uncover gene expression correlations over subsets of samples with the aim of providing a more accurate model of the natural gene functional classes. This approach also has the potential to aid functional annotation of unclassified open reading frames (ORFs). Until now this aspect of biclustering has been under-explored. In this work we illustrate how bicluster analysis may be extended into a 'semi-supervised' ORF annotation approach referred to as BALBOA.</p> <p>Results</p> <p>The efficacy of the BALBOA ORF classification technique is first assessed via cross validation and compared to a multi-class <it>k</it>-Nearest Neighbour (kNN) benchmark across three independent gene expression datasets. BALBOA is then used to assign putative functional annotations to unclassified yeast ORFs. These predictions are evaluated using existing experimental and protein sequence information. Lastly, we employ a related semi-supervised method to predict the presence of novel functional modules within yeast.</p> <p>Conclusion</p> <p>In this paper we demonstrate how unsupervised classification methods, such as bicluster analysis, may be extended using of available annotations to form semi-supervised approaches within the gene expression analysis domain. We show that such methods have the potential to improve upon supervised approaches and shed new light on the functions of unclassified ORFs and their co-regulation.</p

Design and implementation of a TTCN to C translator

The conformance testing of a protocol implementation, may be logically divided into, the specification of the abstract test suite (ATS) from a formal descnption of the protocol, and the subsequent derivation of the executable test suite (ETS) from the ATS specification. Our concern here is with the latter step, in particular, the automatic derivation of an ATS expressed in the Tree and Tabular Combined Notation (TTCN) to an executable C language equivalent. This process is currently a manual one, and as a consequence is error prone, time consuming, often repetitive and not necessarily consistent. To overcome these problems, there exists the real need for a computer aided, and if possible, fully automatic solution. This study descnbes the design and implementation of a fully working TTCN subset to C language translator, which takes a TTCN ATS and produces an equivalent ETS, with a minimal amount of manual intervention. The methodology used is logically divided into three stages direct TTCN to C language mappings, implementation issues, including the generation of additional code to drive the above mappings, and test system implementation issues. The system was tested using parts of an ETSI ISDN LAPD ATS and the results showed considerable time savings against a similar manual implementation. In conclusion, suggestions are provided to the further development of the TTCN to C translator system, and discussion is given to the apphcation of this tool to a complete conformance testing system

Management Challenges from Predator-Prey Effects on the Gallatin Canyon Elk Herd

The Gallatin Canyon elk (Cervus elephus) herd northwest of Yellowstone National Park (YNP), is among the most historic and heavily-researched herds in Montana. Counts, classifications, and harvest records extend from 1919 to present, with intensive wolf-elk research conducted over 2001-2006. The herd remained remarkably stable for more than 80 years, averaging ~1900 wintering elk from 1919-1985. After a data gap spanning 1985-1996, wintering elk counts showed alarming declines, with an average of 960 wintering elk counted over 1996-2010 and 511 counted in 2010. We used harvest records, aerial surveys, and telemetry on elk and wolves (Canis lupus) to determine mortality/predation rates and elk numbers, movements and distribution. From these data we developed a variety of population models to quantify effects of wolf predation and hunter harvest on elk in the Gallatin Canyon. Closed population models suggested a yearly elk population decline of 1-15 percent, whereas open population models suggested a decline of 30 percent, indicating losses due to deaths and emigration. Predator-prey ratios in the Gallatin are among the highest recorded in Montana, similar only to the unhunted elk populations of the Madison Headwaters (YNP). Like the Madison Headwaters, the Gallatin elk herd showed declines from direct predation and emigration loss. matrix models suggested hunting has a negligible population effect compared to predation, yet hunting is the only factor MFWP is currently able to moderate. We are left with a management paradox: hunting is not sustainable in this declining population, yet cessation of hunting will not reverse the elk population declines and will eliminate a treasured hunting opportunity that some families have enjoyed for generations

The length of the teacher\u27s professional life

The figures given in this paper are based on data supplied by five of the Australian States. The aim of the investigation was to obtain some indication of the average length of service of teachers employed by the State Education Departments. The method used was to ascertain the age on retirement, the length of service, and the cause of retirement of each teacher who ceased to be employed by the various Departments during the years 1928, 1929 and 1930. (p.1

CTIX Message System User\u27s Manual Version 1.0

This manual describes how to use the CTIX Message System for interprocess communication in a distributed application program. The CTIX Message System is a package of message-passing facilities developed by the Concurrent Systems Group of the Department of Computer Science at Washington University, It provides a process-to-process asynchronous, buffered communication medium. The package is implemented on a network of Convergent Technologies (CT) MiniFrame workstations. These workstations support the CTIX (the Ct\u27s version of UNIX System V) operating system and the TCP/IP network protocols

Analyzing Discrepancies in a Software Development Project Change Request (CR) Assessment Process and Recommendations for Process Improvements

The Change Request (CR) assessment process is essential in the display development cycle. The assessment process is performed to ensure that the changes stated in the description of the CR match the changes in the actual display requirements. If a discrepancy is found between the CR and the requirements, the CR must be returned to the originator for corrections. Data was gathered from each of the developers to determine the type of discrepancies and the amount of time spent assessing each CR. This study sought to determine the most common types of discrepancies, and the amount of time required to assessing those issues. The study found that even though removing discrepancy before an assessment would save half the time needed to assess an CR with a discrepancy, the number of CR's found to have a discrepancy was very small compared to the total number of CR's assessed during the data gathering period

Accurate Sound Localization in Reverberant Environments Is Mediated by Robust Encoding of Spatial Cues in the Auditory Midbrain

In reverberant environments, acoustic reflections interfere with the direct sound arriving at a listener's ears, distorting the spatial cues for sound localization. Yet, human listeners have little difficulty localizing sounds in most settings. Because reverberant energy builds up over time, the source location is represented relatively faithfully during the early portion of a sound, but this representation becomes increasingly degraded later in the stimulus. We show that the directional sensitivity of single neurons in the auditory midbrain of anesthetized cats follows a similar time course, although onset dominance in temporal response patterns results in more robust directional sensitivity than expected, suggesting a simple mechanism for improving directional sensitivity in reverberation. In parallel behavioral experiments, we demonstrate that human lateralization judgments are consistent with predictions from a population rate model decoding the observed midbrain responses, suggesting a subcortical origin for robust sound localization in reverberant environments.National Institutes of Health (U.S.) (Grant R01 DC002258)National Institutes of Health (U.S.) (Grant R01 DC05778-02)core National Institutes of Health (U.S.) (Eaton Peabody Laboratory. (Core) Grant P30 DC005209)National Institutes of Health (U.S.) (Grant T32 DC0003

Process intensification: Case study with a CHO-based monoclonal antibody production process

Standard platform technologies for cell culture processing provide simple and robust strategies to meet rapid timelines for early process development and ease of manufacturing. However, when there is a need to achieve high antibody titers due to high product demand, both culture media and feed strategies must be customized for specific cell lines. Two case studies will describe the strategies employed as part of a process intensification effort to overcome the limitations of a platform Phase III cell culture process. The first case study will demonstrate an intensified fed-batch process development effort performed to maximize production of a CHO-based monoclonal antibody, while maintaining product quality comparability with the original Phase III process. The second case study will describe the evaluation of a concentrated fed-batch process using alternating tangential flow filtration to retain the protein in the bioreactor, and achieve even higher titers in support of the high product demand forecast. These case studies will show that the intensified fed-batch process improved titers by 50%, and the concentrated fed-batch process improved titers by 100% relative to the fed-batch platform