Sperm cells as vectors for introducing foreign DNA into eggs: Genetic transformation of mice

The oral streptococci are normally non-pathogenic residents of the human microflora. There is substantial evidence that these bacteria can, however, act as "genetic reservoirs" and transfer genetic information to transient bacteria as they make their way through the mouth, the principal entry point for a wide variety of bacteria. Examples that are of particular concern include the transfer of antibiotic resistance from oral streptococci to Streptococcus pneumoniae. The mechanisms that are used by oral streptococci to exchange genetic information are not well-understood, although several species are known to enter a physiological state of genetic competence. This state permits them to become capable of natural genetic transformation, facilitating the acquisition of foreign DNA from the external environment. The oral streptococci share many similarities with two closely related Gram-positive bacteria. S. pneumoniae and Bacillus subtilis. In these bacteria, the mechanisms of quorum-sensing, the development of competence, and DNA uptake and integration are well-charaterized. Using this knowledge and the data available in genome databases allowed us to identify putative genes involved in these processes in the oral organism Streptococcus mutans. Models of competence development and genetic transformation in the oral streptococci and strategies to confirm these models are discussed. Future studies of competence in oral biofilms, the natural environment of oral streptococci, will be discussed.

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Sperm cells and foreign DNA: a controversial relation

BioEssays ◽

10.1002/(sici)1521-1878(199811)20:11<955::aid-bies11>3.0.co;2-8 ◽

1998 ◽

Vol 20 (11) ◽

pp. 955-964 ◽

Cited By ~ 86

Author(s):

Corrado Spadafora

Keyword(s):

Sperm Cells ◽

Foreign Dna

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GENETIC TRANSFORMATION OF ROSE (ROSA SPP) USING THE BIOLISTIC PROCESS.

HortScience ◽

10.21273/hortsci.27.6.659e ◽

1992 ◽

Vol 27 (6) ◽

pp. 659e-659

Author(s):

M. S. Strefeler

Keyword(s):

Gene Transfer ◽

Genetic Transformation ◽

Transformation Efficiency ◽

New Genes ◽

Improvement Programs ◽

Foreign Dna ◽

Cultivar Improvement ◽

Time Required ◽

Biolistic Process ◽

Elite Germplasm

Genetic transformation of cut roses may greatly facilitate cultivar improvement programs by shortening the time required to introduce new genes into elite germplasm. The biolistic process offers a very promising method for the genetic transformation of roses. The biolistic process uses high velocity mircoprojectiles (gold or tungsten) to carry foreign DNA into cells. This process has been shown to be useful for genetic transformation of many organisms. The first step in taking advantage of this process is to optimize the factors which affect transformation efficiency. Several factors that have a significant affect on transformation efficiency were examined in an effort to optimize the biolistic process for gene transfer in roses. The factors examined were type of tissue (leaf segments, petioles, callus, etc), bombardment distance, the number of bombardments, DNA construct and microcarrier velocity. The reporter gene, GUS, was used for determining transformation efficiency in this study. GUS was carried on several plasmid constructs which also contained antibiotic resistance (kanamycin or streptomycin. Efficiency of gene transfer was determined by calculating the number of transiently expressing GUS cells for each combination of factors. Results of this study will be discussed and summarized.

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Failure to produce transgenic offspring by intra-tubal insemination of gilts with DNA-treated sperm

Reproduction Fertility and Development ◽

10.1071/rd9961055 ◽

1996 ◽

Vol 8 (7) ◽

pp. 1055 ◽

Cited By ~ 21

Author(s):

F Gandolfi ◽

M Terqui ◽

S Modina ◽

TA Brevini ◽

P Ajmone-Marsan ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Plasmid Dna ◽

Sperm Cells ◽

Chain Reaction ◽

Exogenous Dna ◽

Pig Genome ◽

Foreign Dna ◽

Polymerase Chain ◽

Boar Spermatozoa ◽

Dna Incorporation

The reproducibility of the use of sperm cells as vectors of foreign DNA in the genome of pigs was verified in the present study and the effectiveness of four different procedures for sperm treatment was assessed. For each gilt, approximately 6 x 10(6) ejaculated boar spermatozoa were incubated for 30 min in 1 mL TALP medium containing 3 micrograms of linearized pSV2CAT plasmid DNA. Before incubation, spermatozoa were treated in four experimental groups: (1) cells were stored at 16 degrees C for 24 h and then washed three times in TALP; (2) cells from the fresh, undiluted sperm-rich fraction of an ejaculate were used immediately after collection, following the same procedure as (1); (3) cells were treated as in (2) with an extra wash; and (4) incubation with DNA was performed in TALP medium supplemented with 0.5 mg mL(-1) poly-L-lysine hydrobromide. As determined by immunolocalization, plasmid DNA molecules were found to be associated with 12-17.1% spermatozoa, depending on sperm treatment. Of 35 inseminated gilts, 20 gave birth to a total of 126 piglets. None of the piglets showed sign of exogenous DNA incorporation in any of the tissues tested, as assessed by the polymerase chain reaction and Southern blot. The potential of modifying the pig genome through 'transformed' spermatozoa was not confirmed by these experiments.

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NRPS-gene disruption in the apple-pathogen, Neonectria ditissima

10.1101/2021.04.01.438028 ◽

2021 ◽

Author(s):

Heriberto V&eacutel&eumlz ◽

Salim Bourras ◽

Larisa Garkava-Gustavsson ◽

Kerstin Dalman

Keyword(s):

Genetic Transformation ◽

Gene Disruption ◽

Fruit Tree ◽

Infection Process ◽

Nrps Gene ◽

Transformation Technique ◽

Targeted Gene Disruption ◽

Apple Production ◽

Foreign Dna

Apple production in Sweden and elsewhere is being threaten by the fungus, Neonectria ditissima, which causes a disease known as Fruit Tree Canker. The disease can cause extensive damages and the removal of diseased-wood and heavily infected trees can be laborious and expensive. Currently, there is no way to eradicate the fungus from infected trees and our knowledge of the infection process is limited. Thus, in order to target and modify genes efficiently, the genetic transformation technique developed for N. ditissima back in 2003 was modified. We report on the upgraded protocol and show that protoplasts were viable, able to uptake foreign DNA, and able to regenerate back into a mycelial colony, either as targeted gene-disruption mutants or as ectopic mutants expressing GFP.

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Sperm cells as vectors for introducing foreign DNA into zebrafish

Aquaculture ◽

10.1016/0044-8486(92)90046-n ◽

1992 ◽

Vol 107 (1) ◽

pp. 1-19 ◽

Cited By ~ 57

Author(s):

H.-W. Khoo ◽

L.-H. Ang ◽

H.-B. Lim ◽

K.-Y. Wong

Keyword(s):

Sperm Cells ◽

Foreign Dna

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Steady at the wheel: conservative sex and the benefits of bacterial transformation

10.1101/062562 ◽

2016 ◽

Cited By ~ 2

Author(s):

Ole Herman Ambur ◽

Jan Engelstädter ◽

Pål J. Johnsen ◽

Eric L. Miller ◽

Daniel E. Rozen

Keyword(s):

Genetic Transformation ◽

Large Body ◽

Theoretical Studies ◽

Bacterial Cells ◽

Bacterial Transformation ◽

Bacterial Populations ◽

Direct Benefits ◽

Foreign Dna ◽

Genomic Conservation ◽

Natural Genetic Transformation

SummaryMany bacteria are highly sexual, but the reasons for their promiscuity remain obscure. Did bacterial sex evolve to maximize diversity and facilitate adaptation in a changing world, or does it instead help to retain the bacterial functions that work right now? In other words, is bacterial sex innovative or conservative? Our aim in this review is to integrate experimental, bioinformatic and theoretical studies to critically evaluate these alternatives, with a main focus on natural genetic transformation, the bacterial equivalent of eukaryotic sexual reproduction. First, we provide a general overview of several hypotheses that have been put forward to explain the evolution of transformation. Next, we synthesize a large body of evidence highlighting the numerous passive and active barriers to transformation that have evolved to protect bacteria from foreign DNA, thereby increasing the likelihood that transformation takes place among clonemates. Our critical review of the existing literature provides support for the view that bacterial transformation is maintained as a means of genomic conservation that provides direct benefits to both individual bacterial cells and to transformable bacterial populations. We examine the generality of this view across bacteria and contrast this explanation with the different evolutionary roles proposed to maintain sex in eukaryotes.

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Ultrastructure of Testicular Spermatozoon of the Fish Oreochromis Niloticus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103450 ◽

1988 ◽

Vol 46 ◽

pp. 278-279

Author(s):

T. Guha ◽

A. Q. Siddiqui ◽

P. F. Prentis

Keyword(s):

Electron Microscope ◽

Oreochromis Niloticus ◽

Osmium Tetroxide ◽

Sperm Cells ◽

Adult Fish ◽

Testicular Sperm ◽

Thin Sections ◽

Important Fish ◽

Testicular Spermatozoon ◽

Diamond Knife

Tilapia, Oreochromis niloticus, is an economically important fish in Saudi Arabia. Elucidation of reproductive biology of this species is necessary for successful breeding program. In this paper we describe fine structure of testicular sperm cells in O, niloticus.Testes from young adult fish were fixed in gluteraldehyde (2%) and osmium tetroxide (1%), both in cacodyl ate buffer. Specimens were processed in the conventional way for electron microscopy and thin sections of tissues (obtained by cutting the blocks with a diamond knife) were stained by ura- nyl acetate and lead citrate. These were examined in a Carl Zeiss electron microscope operated at 40 kV to 60 kV. Sperm cells were obtained from testes by squeezing them in cacodyl ate buffer. They were fixed in gluteraldehyde (2%) in the same buffer, air dried, gold coated and then examined in a Philips scanning electron microscope (SEM) operated at 25kV.The spermatozoon of O. niloticus is consisting of head, midpiece and tail (Fig. 1).

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