scholarly journals [6N]METHYL ADENINE IN THE NUCLEAR DNA OF A EUCARYOTE, TETRAHYMENA PYRIFORMIS

1973 ◽  
Vol 56 (3) ◽  
pp. 697-701 ◽  
Author(s):  
Martin A. Gorovsky ◽  
Stanley Hattman ◽  
Gloria Lorick Pleger
Keyword(s):  
Nuclear Dna ◽  
Tetrahymena Pyriformis ◽  
The Other ◽  
Other Hand ◽  
Different Strains

DNA isolated from macronuclei of the ciliate, Tetrahymena pyriformis, has been found to contain [6N]methyl adenine (MeAde); this represents the first clear demonstration of significant amounts of MeAde in the DNA of a eucaryote. The amounts of macronuclear MeAde differed slightly between different strains of Tetrahymena, with approximately 0.65–0.80% of the adenine bases being methylated. The MeAde content of macronuclear DNA did not seem to vary in different physiological states. The level of MeAde in DNA isolated from micronuclei, on the other hand, was quite low (at least tenfold lower than in macronuclear DNA).

scholarly journals A Contribution to the Study of Meningococci

1918 ◽  
Vol 17 (4) ◽  
pp. 380-404 ◽  
Author(s):  
E. W. Ainley Walker
Keyword(s):  
Bacterial Species ◽  
The Other ◽  
Immunological Methods ◽  
Other Hand ◽  
The One ◽  
Different Strains ◽  
Micro Organisms

It has been shown by numerous observers that well-marked serological differences are found between different strains of meningococci. And since the work of Dopter on the relation of “parameningococci” to meningococci and to cerebro-spinal fever, there has arisen a fairly general agreement that among meningococci capable of causing cerebrospinal meningitis two broadly separable groups can be defined by immunological methods. But beyond this point considerable divergences of opinion appear. On the one hand there are a number of recent workers who have failed to convince themselves that the two groups of meningococci are in reality clearly delimited, permanent and independent entities. On the other hand certain other workers claim to have still further subdivided these micro-organisms into four definite and independent types, each of which possesses in itself the value of a bacterial species [cp. Andrewes (1917)].

Breeding

1939 ◽  
Vol 12 (1-2) ◽  
pp. 27-55
Keyword(s):  
The Other ◽  
List Type ◽  
Type Number ◽  
Other Hand ◽  
Average Production ◽  
Eye Colour ◽  
White Leghorns ◽  
The One ◽  
Different Strains

The connection between the Colour of the Eyes, the Mortality, and the Production of White Leghorns. Het Verband tusschen de oogkleur van Witte Leghorns en de Herfte en de productie. Dr. J. B. van der Meulen. Landbouwkundig Tijdschrift, Vol. 50, 1938, p. 868.An investigation, in which 406 White Leghorns of two different strains were used, on the connection between the colour of the eyes of normal healthy pullets at the beginning of the laying period on the one hand and the production and mortality during the pullet year on the other hand, led to the following conclusions:—1.The mortality amongst hens with abnormal colour of the eyes, (brown-grey and/or blue) is considerably higher than that amongst birds with normal orange coloured eyes, and the production of the former is on the average lower than that of the latter.2.Birds with one normal and one abnormal coloured eyes, correspond to birds with normal coloured eyes as far as mortality is concerned, but their average production resembles more than that of birds with two abnormal eyes.3.Not only an abnormal eye colour but also an abnormal shape of the pupil seems to point to higher mortality and the highest mortality is probable amongst birds which have both an abnormal colour, as well as an abnormal shape of the pupil.

THE ATTRACTING BASINS AND THE ASSESSMENT OF THE TRANSMISSION COEFFICIENTS FOR HIV AND M. TUBERCULOSIS INFECTIONS AMONG WOMEN INMATES

2002 ◽  
Vol 10 (01) ◽  
pp. 61-83 ◽  
Author(s):  
SILVIA MARTORANO RAIMUNDO ◽  
HYUN MO YANG ◽  
RODNEY CARLOS BASSANEZI ◽  
MARIZETE A. C. FERREIRA
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Women Inmates ◽  
Compartmental Model ◽  
Basins Of Attraction ◽  
The Other ◽  
Transmission Coefficients ◽  
Other Hand ◽  
Cross Immunity ◽  
Different Strains

It has been observed that in many cases one infection can partially protect against another infection or it may lead to a co-infection. For instance, the interaction between infections with different strains, like dengue and malaria or tuberculosis and lepra, induces cross immunity. On the other hand, individuals infected with HIV are much more susceptible to other infections, for instance, tuberculosis. We propose a compartmental model to describe the transmission of AIDS and tuberculosis in a closed community as an example of one infection activating the other one. When studying the dynamics of the interactions we obtain basins of attraction where one infection prevails over the other one and where both infections coalesce. Furthermore, we are taking into account an adaptation of the model in order to assess the transmission coefficients for HIV and Mycobacterium tuberculosis infections among women inmates.

Investigations in crop husbandry. II. On the age of seed beans

1935 ◽  
Vol 25 (3) ◽  
pp. 361-368
Author(s):  
F. H. Garner ◽  
H. G. Sandees
Keyword(s):  
Field Experiments ◽  
Early Spring ◽  
The Other ◽  
Large Seed ◽  
Other Hand ◽  
Crop Husbandry ◽  
The Difference ◽  
Different Strains

1. New and old seed beans have been compared for three years, in the last two of which precise field experiments have been conducted with two different strains.2. In general new seed gave higher yields than old seed, but the difference was only of the order of 10 per cent. There was some evidence that conditions when the seed was harvested might be more important than age.3. New seed produced more branches in early spring, and a greater number of pod-bearing stems at harvest; on the other hand, old seed produced stems that were more thickly podded at harvest, and pods that contained a greater number of beans.4. In one case abnormally large seed produced very vigorous plants, and very large beans at harvest.

scholarly journals Influence of chemical and physical conditions on the production of bacteriocin by Aeromonas hydrophila

2012 ◽  
Vol 9 (2) ◽  
pp. 259-269
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aeromonas Hydrophila ◽  
Pathogenic Bacteria ◽  
Brain Heart Infusion ◽  
Inhibition Zone ◽  
The Other ◽  
Bacterial Strains ◽  
Physical Conditions ◽  
Other Hand ◽  
Wide Range ◽  
Different Strains

Aeromonas hydrophila have been isolated as a cause of a cute gastroenteritis in 23 (5.6%) of 410 patients. Other bacterial enteropathogens have been isolated from 387 patients with diarrhea, were 19 different strains. A. hydrophila occurred more commonly in children with acute diarrhea, the results showed that 18(78.26%) isolates of A. hydrophila found in children under 10 years old ,distributed to 10(43.47%) in male and 8(34.78%) in female ,and in adults with diarrhea 5 (21.73%). In the other hand, we noticed frequency of isolation was higher in male 14(60.86%) when compared with 9(39.14%) in female. Six strains of A. hydrophila have been observed to have bacteriocin activity against 12 of 23 different A. hydrophila ,as well as Staphylococcus aureas, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacea and Shigella dysenteria. The results showed Bacteriocin-like substances (BLS11) had isoinhibitory activity on 10 same A. hydrophila species and heteroinhibitory activity effects on all pathogenic bacterial strains used, while BLS5 showed isoinhibitory activity on 2 same A. hydrophila species and heteroinhibitory activity by effecting on gram negative only, and BLS3& BLS12 showed activity on E. coli isolates only, and none of BLS1& BLS10(isoinhibitory activity on 1 A.hydrophila respectively) had effect on all pathogenic bacteria. Among the standard laboratory media used Brain Heart Infusion broth (BHI) showed the maximum production and poor yields resulted from growth in Peptone Glyserol (PG) and Nutrient broth. We selected BLS11 to their wide range effect on same species and enteric pathogenic strains, to study the Influence of chemical and physical conditions on the production of BLS by A.hydrophila. The BLS11 preparations from A.hydrophila11 strains of A. hydrophila were tolerant to all three treatments of surfactant. In the other hand, effect of organic acid on BLS production BLS11 has been studied and showed no remarkable difference in zone of inhibition when used acetone as affecter element, while both of isopropanol and ethanol have narrow inhibition zone range when compared with control strain. These results indicated that most A. hydrophila might be harboring plasmid mediated bacteriocin like substance, and there are no relation between BLS production and number of plasmid bands present in bacteria.

scholarly journals Characterization of cytoplasmic and nuclear genomes in the colorless alga Polytoma. III. Ribosomal RNA cistrons of the nucleus and leucoplast.

1976 ◽  
Vol 69 (2) ◽  
pp. 383-392 ◽  
Author(s):  
C Siu ◽  
K Chiang ◽  
H Swift
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Ribosomal Rna ◽  
Nuclear Dna ◽  
Buoyant Density ◽  
Nuclear Genome ◽  
The Other ◽  
Heterologous Hybridization ◽  
Other Hand ◽  
Specific Hybridization

The colorless alga Polytoma obtusum has been found to possess leucoplasts, and two kinds of ribosomes with sedimentation values of 73S and 79S. The ribosomal RNA (rRNA) of the 73S but not the 79S ribosomes was shown to hybridize with the leucoplast DNA (rho - 1.682 g/ml). Nuclear DNA of Polytoma (rho = 1.711) showed specific hybridization with rRNA from the 79S ribosomes. Saturation hybridization indicated that only one copy of the rRNA cistrons was present per leucoplast genome, with an average buoyant density of rho = 1.700. On the other hand, about 750 copies of the cytoplasmic rRNA cistrons were present per nuclear genome with a density of rho = 1.709. Heterologous hybridization studies with Chlamydomonas reinhardtii rRNAs showed an estimated 80% homology between the two cytoplasmic rRNAs, but only a 50% homology between chloroplast and leucoplast rRNAs of the two species. We conclude that the leucoplasts of Polytoma derive from chloroplasts of a Chlamydomonas-like ancestor, but that the leucoplast rRNA cistrons have diverged in evolution more extensively than the cistrons for cytoplasmic rRNA.

Replication of Macronuclear DNA in the Cytoplasm of Tetrahymena Pyriformis

1974 ◽  
Vol 14 (2) ◽  
pp. 289-300
Author(s):  
H. A. ANDERSEN
Keyword(s):  
Cell Division ◽  
Dna Replication ◽  
Nuclear Dna ◽  
Tetrahymena Pyriformis ◽  
Cell Generation ◽  
The Other ◽  
Previous Generation ◽  
Cytoplasmic Dna ◽  
Continue Growth ◽  
S Period

Previous experiments showed that a synchronous population of Tetrahymena could divide even though DNA replication was blocked during the latter half of the preceding S-period by addition of methotrexate plus uridine (M + U). Furthermore, it was found that the DNA fraction which was in replication at the time of inhibition became localized in the cytoplasm following elimination from the nucleus at the time of division. When the inhibitory treatment (M + U) was removed prior to or at the time of the cell division the cells were found to engage in new DNA replication and continue growth. Two questions arose from these studies. First, is the DNA replication normal following release from M + U? Second, what is the fate of the cytoplasmic DNA? In the present paper DNA replication has been studied using incorporation of 5-bromodeoxyuridine and centrifugation of the labelled DNA in CsCl gradients. It is concluded that the DNA which finished replication prior to the effect of the M + U treatment replicates again during the S-period of the next cell generation. On the other hand, the DNA fraction which was stalled in replication and subsequently eliminated from the nucleus also replicates in the cytoplasm in the next generation but during G2 period, out of phase with the undamaged nuclear DNA. The cytoplasmic DNA replication appeared to be a continuation of the replication initiated in the nucleus in the previous generation.

scholarly journals Jean claude Perez § Luc Montagnier - COVID-19, SARS and Bats Coronaviruses Genomes Unexpected Exogenous RNA Sequences

2020 ◽  
Author(s):  
jean-claude perez
Keyword(s):  
Small Region ◽  
Plasmodium Yoelii ◽  
The Other ◽  
Rna Sequences ◽  
Synonymous Codons ◽  
Synthetic Genome ◽  
Other Hand ◽  
Cumulative Length ◽  
The One ◽  
Different Strains

We are facing the worldwide invasion of a new coronavirus. This follows several limited outbreaks of related viruses in various locations in a recent past (SARS, MERS). Although the main objective of researchers is to bring efficient therapeutic and preventive solutions to the global population, we need  also to better  understand the origin of the newly coronavirus-induced epidemic in order to avoid future outbreaks. The present molecular appraisal is to study by a bio-infomatic approach the facts relating to the virus and its precursors. This article shows how 16 fragments (Env Pol and Integrase genes) from different strains, both diversified and very recent, of the HIV1, HIV2 and SIV retroviruses most likely are present into the genome of COVID-19. Among these fragments, 12 are concentrated in a very small region of the COVID-19 genome, length less than 900bases, i.e. less than 3% of the total length of this genome. In addition, these footprints are positioned in 2 functional genes of COVID-19: the orf1ab and S spike genes. To sum up, here are the two main facts which contribute to our hypothesis of a partially synthetic genome: A contiguous region representing 2.49% of the whole COVID-19 genome of which 40.99% is made up of 12 diverse fragments originating from various strains of HIV SIV retroviruses. On the other hand, these 12  fragments some of which appear concatenated. Notably, the retroviral part of these regions, which consists of 8 elements from various strains HIV1, HIV2 and SIV covers a length of 275 contiguous bases of COVID-19. The cumulative length of these 8 HIV SIV elements represents 200 bases. Consequently, the HIV SIV density rate of this region of COVID-19 is 200/275 = 72.73%, which is considerable s made of. Moreover each of these elements is made of 18 or more nucleotides and therefore may have function. They are called Exogenous Informative Elements. A major part of these 16 EIE already existed in the first SARS genomes as early as 2003. However, we demonstrate how and why a new region including 4 HIV1 HIV2 Exogenous Informative Elements radically distinguishes all COVID-19 strains from all SARS and Bat strains. We then gather facts about the possible origins of COVID_19. We have particularly analyzed this small region of 225 bases common to COVID_19 and batRaTG13 but totally absent in all SARS strains. Then, we discuss the case of bat genomes presumed to be at the origin of COVID_19. In the strain of bat RaTG13 coronavirus isolated in 2013, then sequenced in 2020, the homology profile for HIV1 Kenya 2008 fragment is identical to that of COVID_19. Finally, we have studied the most recent genetic evolution of the COVID_19 strains involved in the world epidemic. We found a significant occurrence of mutations and deletions in the 225b region.On sampling genomes, we finally show that this 225b key region of each genome, rich in EIE, evolves much faster than the corresponding whole genome.The comparative analysis of the SPIKES genes of COVID_19 and Bat RaTG13demonstrates two abnormal facts: on the one hand, the insertion of 4 contiguous amino acids in the middle of SPIKE, on the other hand, an abnormal distribution of synonymous codons in the second half of SPIKE. Finally the insertion in this region of an EIE coming from a Plasmodium Yoelii gene is demonstrated, but above all seems to explain the "strategy" pursued by having "artificially" modified the ratio of synonym codons / non-synonymous codons in this same region of 1770 COVID_19 SPIKE nucleotides.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

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