scholarly journals Extraction of genomic DNA from Melipona quadrifasciata (Hymenoptera: Apidae, Meliponinae)

1997 ◽  
Vol 20 (3) ◽  
pp. 421-423 ◽  
Author(s):  
Ana Maria Waldschmidt ◽  
Tânia Maria Fernandes Salomão ◽  
Everaldo Gonçalves de Barros ◽  
Lúcio de Antônio Oliveira Campos

The objective of the present study was to test three different procedures for DNA extraction of Melipona quadrifasciata based on existing methods for DNA extraction of Apis, plants and fungi. These methods differ in the concentrations of specific substances in the extraction buffer. The results demonstrate that the method used for Apis is not adequate for DNA extraction from M. quadrifasciata. On the other hand, with minor modifications this method and the methods for plants and fungi were adequate for DNA extraction of this stingless bee, both for adults and larvae

Nativa ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 97
Author(s):  
Eliane Cristina Moreno de Pedri ◽  
Catiane Dos Santos Braga ◽  
Carlos Alberto Da Cunha Oliveira ◽  
Auana Vicente Tiago ◽  
Ana Aparecida Bandini Rossi

O estabelecimento de protocolo de extração de DNA de espécies vegetais é uma técnica empregada para a obtenção de um DNA puro e de qualidade. Diante disso, objetivou-se neste estudo padronizar um protocolo para a extração de DNA da espécie Acianthera ciliata, visando posteriores estudos de diversidade genética. Foram testados dois métodos de trituração do tecido foliar, sendo eles: Tampão STE e nitrogênio líquido. Para cada método de trituração foram testadas duas concentrações de β-mercaptoetanol (0% e 2%). Os dois métodos utilizados, foram eficientes na extração do DNA genômico de A. ciliata. As amostras extraídas com 0% de β-mercaptoetanol, para os dois métodos, STE e nitrogênio líquido, apresentaram menor quantidade de DNA quando comparado com as amostras extraídas com 2% de β-mercaptoetanol. Os dois primers testados amplificaram regiões do genoma de A. ciliata. Para a extração de DNA de A. ciliata indica-se a utilização de CTAB 5% no tampão de extração e β-mercaptoetanol a 2%. Os iniciadores ISSR foram eficientes na amplificação e são recomendados para estudos de diversidade genética de A. ciliata.Palavras-chave: diversidade genética; CTAB; marcadores moleculares; orquídeas. EVALUATION OF TWO MACERATION METHODS IN Acianthera ciliata (Orchidaceae) LEAVES FOR DNA EXTRACTION ABSTRACT: The establishment of DNA extraction protocol for plant species is a technique employed to obtain pure and good quality DNA. In this study, we standardized a protocol for the extraction of DNA of the species Acianthera ciliata, aiming studies of genetic diversity subsequently. Two maceration methods for foliar tissue were tested, and they were STE buffer and liquid nitrogen. Two concentrations of β-mercaptoethanol (0% and 2%) were tested for each method. The two methods used were efficient for genomic DNA extraction of A. ciliata. In both methods the samples extracted using 0% of β-mercaptoethanol, they presented lesser amount of DNA than the samples extracted using 2% of β-mercaptoethanol. The two tested primers amplified genomic regions of A. ciliata. For the DNA extraction of A. ciliata, we indicated the use of CTAB 5% in the extraction buffer as well as β-mercaptoethanol to 2%. The ISSR primers were efficient in amplification and thus they are indicated for studies of genetic diversity of A. ciliata.Keywords: genetic diversity; CTAB; molecular markers; orchids.


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

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.


Author(s):  
A. V. Crewe

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.


Author(s):  
K.H. Westmacott

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.


2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.


1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  

2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.


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