scholarly journals Characterization of a transgenic mouse line over-expressing the human ornithine decarboxylase gene

1991 ◽  
Vol 278 (3) ◽  
pp. 895-898 ◽  
Author(s):  
M Halmekytö ◽  
L Alhonen ◽  
J Wahlfors ◽  
R Sinervirta ◽  
T Eloranta ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Ornithine Decarboxylase ◽  
Transgenic Animals ◽  
Metabolizing Enzymes ◽  
Transgenic Mouse Line ◽  
Adenosylmethionine Decarboxylase ◽  
Transgenic Lines ◽  
Polymerase Chain

We have produced several transgenic mouse lines over-expressing the human ornithine decarboxylase (ODC) gene. We have now characterized one of the transgenic lines as regards the tissue accumulation of the polyamines and the activities of their metabolizing enzymes. Among the tissues analysed, the polyamine pattern was most strikingly changed in testis and brain of the transgenic animals. ODC activity was greatly enhanced in all tissues, except kidney, of the transgenic animals. The most dramatic increase, 80-fold, was found in brain of the transgenic mice. The activities of S-adenosylmethionine decarboxylase and spermidine and spermine syntheses were likewise significantly increased in testis of the transgenic animals. The activities of the enzymes involved in the back-conversion of the polyamines, namely spermidine/spermine acetyltransferase and polyamine oxidase, were similar in the transgenic and non-transgenic animals. As analysed by reverse transcriptase/polymerase chain reaction, all the six tissues of the transgenic animals expressed human-specific ODC mRNA. Determination of the half-life of testicular ODC revealed a stabilization of the enzyme in the transgenic males.

scholarly journals Transgenic mice over-producing putrescine in their tissues do not convert the diamine into higher polyamines

1993 ◽  
Vol 291 (2) ◽  
pp. 505-508 ◽  
Author(s):  
M Halmekytö ◽  
L Alhonen ◽  
L Alakuijala ◽  
J Jänne
Keyword(s):  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Ornithine Decarboxylase ◽  
Specific Inhibitor ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Adenosylmethionine Decarboxylase ◽  
Adult Tissues ◽  
Ornithine Transaminase

We recently described a transgenic mouse line over-expressing the human ornithine decarboxylase gene virtually in all tissues. Despite strikingly elevated tissue putrescine concentrations, no or minimal changes were found in the levels of the higher polyamines spermidine and spermine. We have now extended these studies by further increasing tissue putrescine with the aid of 5-fluoromethylornithine, a specific inhibitor of ornithine transaminase and hence the catabolism of L-ornithine. As a result of the treatment with the latter drug, the concentration of putrescine was further increased by a factor of 2-3 without any changes in the concentrations of spermidine and spermine. In the testis of transgenic mice treated with 5-fluoromethylornithine, the concentration of putrescine was nearly 60 times that in non-transgenic untreated animals, yet the concentration of spermidine was only 1.5-fold higher. A similar small increase in brain spermidine was accompanied by a 40-fold elevation in the concentration of putrescine. The apparent blockade between putrescine and spermidine was in all likelihood not attributable to an inhibition of S-adenosylmethionine decarboxylase, the rate-controlling enzyme in the biosynthesis of spermidine and spermine. Our results are more compatible with the view that in non-dividing adult tissues putrescine is sequestered through some unknown mechanisms in a way that makes it unavailable for the synthesis of the higher polyamines.

scholarly journals First Isolation and Molecular Typing of Pathogenic and Intermediate Leptospira Species from Urine of Symptomatic Dogs

2021 ◽  
Vol 8 (12) ◽  
pp. 304
Author(s):  
Ivana Piredda ◽  
Loris Bertoldi ◽  
Giuseppe Benvenuto ◽  
Bruna Palmas ◽  
Aureliana Pedditzi ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Zoonotic Risk ◽  
Leptospira Spp ◽  
Blood And Urine Samples ◽  
Healthy Dogs ◽  
Polymerase Chain ◽  
Sequence Types ◽  
Leptospira Species

Aim of this study was to evaluate, the presence and diversity of Leptospira spp. in blood and urine samples collected from 175 owned-dogs from Sardinia, Italy. After determination of leptospiral infection by microscopic agglutination test (MAT), urine from MAT-positive dogs were examined by real-time polymerase chain reaction (lipL32 rt-PCR) and then isolated by culture. In order to characterize obtained serovars, positive cultures were then subjected to 16S rRNA and secY sequencing, phylogenetic analysis and Multilocus Sequence Typing (MLST). Results showed that seven dogs (4%; 95% CI: 0–55) had Leptospira DNAs in their urine and five strains were isolated from urine cultures. The three different sequence types (ST17, ST198 and ST24) belonging to Leptospira interrogans genomospecies identified by MLST analyses in this study, confirmed that the leptospiral infection was widespread in Sardinian dogs. We also reported the first characterization of a new Leptospira spp. isolated from urine of one dog living in the study area. Whole genome sequencing and phylogenetic analysis, confirmed that this genospecies was closely related to Leptospira hovindhougenii, an intermediate Leptospira spp. with unknown pathogenicity previously isolated from a rat in Denmark. Further studies are required to clarify whether healthy dogs that shed leptospires in their urine could represent a zoonotic risk for humans in this region.

scholarly journals Overexpression of spermidine/spermine N1-acetyltransferase under the control of mouse metallothionein I promoter in transgenic mice: evidence for a striking post-transcriptional regulation of transgene expression by a polyamine analogue

1999 ◽  
Vol 338 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Suvikki SUPPOLA ◽  
Marko PIETILÄ ◽  
Jyrki J. PARKKINEN ◽  
Veli-Pekka KORHONEN ◽  
Leena ALHONEN ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Cell Injury ◽  
Mrna Level ◽  
Transgenic Animals ◽  
Ultrastructural Changes ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Polyamine Analogue

We recently generated a transgenic mouse line overexpressing spermidine/spermine N1-acetyltransferase (SSAT) gene under its own promoter. The tissue polyamine pools of these animals were profoundly affected and the mice were hairless from early age. We have now generated another transgenic-mouse line overexpressing the SSAT gene under the control of a heavy-metal-inducible mouse metallothionein I (MT) promoter. Even in the absence of heavy metals, changes in the tissue polyamine pools indicated that a marked activation of polyamine catabolism had occurred in the transgenic animals. As with the SSAT transgenic mice generated previously, the mice of the new line (MT-SSAT) suffered permanent hair loss, but this occurred considerably later than in the previous SSAT transgenic animals. Liver was the most affected tissue in the MT–SSAT transgenic animals, revealed by putrescine overaccumulation, significant decrease in spermidine concentration and > 90% reduction in the spermine pool. Even though hepatic SSAT mRNA accumulated to massive levels in non-induced transgenic animals, SSAT activity was only moderately elevated. Administration of ZnSO4 further elevated the level of hepatic SSAT message and induced enzyme activity, but not more than 2- to 3-fold. Treatment of the transgenic animals with the polyamine analogue N1,N11-diethylnorspermine (DENSPM) resulted in an immense induction, more than 40000-fold, of enzyme activity in the liver of transgenic animals, and minor changes in the SSAT mRNA level. Liver spermidine and spermine pools were virtually depleted within 1–2 days in response to the treatment with the analogue. The treatment also resulted in a marked mortality (up to 60%) among the transgenic animals which showed ultrastructural changes in the liver, most notably mitochondrial swelling, one of the earliest signs of cell injury. These results indicated that, even without its own promoter, SSAT is powerfully induced by the polyamine analogue through a mechanism that appears to involve a direct translational and/or heterogenous nuclear RNA processing control. It is likewise significant that overexpression of SSAT renders the animals extremely sensitive to polyamine analogues.

scholarly journals Transgenic mice expressing the human ornithine decarboxylase gene under the control of mouse metallothionein I promoter

1996 ◽  
Vol 314 (2) ◽  
pp. 405-408 ◽  
Author(s):  
Leena ALHONEN ◽  
Sami HEIKKINEN ◽  
Riitta SINERVIRTA ◽  
Maria HALMEKYTÖ ◽  
Pekka ALAKUIJALA ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Mammalian Cells ◽  
Fold Increase ◽  
Transgenic Animals ◽  
Decarboxylase Activity ◽  
Transgenic Mouse Line ◽  
Regulatory Machinery ◽  
Dividing Cells ◽  
Very High

We have generated a transgenic mouse line harbouring the human ornithine decarboxylase gene under the control of mouse metallothionein I promoter. Even in the absence of an exposure to heavy metals, ornithine decarboxylase was over-expressed in heart, testis, brain, and especially in liver, of the transgenic animals. An exposure of the transgenic mice to zinc further enhanced the enzyme activity to a level which in liver represented up to 8000-fold increase in comparison with non-transgenic animals. The striking stimulation of liver ornithine decarboxylase activity upon treatment of the transgenic mice with zinc was accompanied by a nearly 150-fold increase in the hepatic putrescine content as compared with similarly treated non-transgenic animals. Even though the liver putrescine concentration reached that of spermidine and spermine in the transgenic animals, the contents of the higher polyamines only transiently increased upon zinc administration and then returned to the basal level. These findings once again indicate that mammalian cells possess extremely powerful regulatory machinery to prevent an over-accumulation of spermidine and spermine in non-dividing cells, and that very high tissue putrescine concentrations can be tolerated, at least for periods of a few days, with seemingly no phenotypic changes.

scholarly journals Sex Determination During Inflorescence Bud Differentiation in Monoecious Pistacia chinensis Bunge

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 202 ◽  
Author(s):  
Qian Bai ◽  
Chenyi Zhu ◽  
Xia Lei ◽  
Tao Cao ◽  
Shuchai Su ◽  
...  
Keyword(s):  
Sex Determination ◽  
Early Stage ◽  
Sex Differentiation ◽  
Banding Patterns ◽  
Vegetative Period ◽  
Pcr Products ◽  
Polymerase Chain ◽  
Sex Determination Mechanisms

Pistacia chinensis Bunge is widely acknowledged to be dioecious, but rare monoecious individuals have been found. However, the origin of monoecism and the sex differentiation of different sex types remain intriguing questions. Here, sex expressions were explored by identification of sex-associated DNA markers, determination of the sex stability after grafting, and histological characterization of inflorescence bud development using anatomical analysis. The results showed that (1) although polymorphisms among individuals existed, the banding patterns of Polymerase Chain Reaction (PCR) products for different sex types on the same monoecious tree were consistent; (2) the sex expressions of grafted trees were not consistent with those of scions, indicating that monoecism probably did not originate from a stable bud mutation; and (3) both males and females underwent a bisexual period, then the stamen primordia in female buds degenerated into the second round tepals, while the pistil primordia in male buds gradually disappeared. During the sex differentiation phase, female buds were spindle-shaped, while the male buds were full teardrop-shaped, and male buds were bigger than female buds. Taken together, no sex-associated DNA marker was found, sex expressions were unstable after grafting, and the alternative sex organs appeared in the early stage of sex differentiation, suggesting that sex determination occurred during floral development instead of the early vegetative period. These results indicated that the sex expressions may be affected by environmental factors, increasing the understanding of sex determination mechanisms in P. chinensis and other species.

Characterization of a transgenic mouse line lacking photoreceptor development within the ventral retina

2005 ◽  
Vol 81 (4) ◽  
pp. 376-388 ◽  
Author(s):  
Shao-Ling Fong ◽  
Mark H. Criswell ◽  
Teri Belecky-Adams ◽  
Wei-Bao Fong ◽  
Jeanette N. McClintick ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Photoreceptor Development

Future Directions for Pharmacogenetics

1993 ◽  
Vol 6 (1) ◽  
pp. 44-46
Author(s):  
Michael W. Jann ◽  
Y.W. Francis Lam
Keyword(s):  
Molecular Mechanisms ◽  
Regulatory Control ◽  
Ethnic Variation ◽  
Metabolizing Enzymes ◽  
Future Directions ◽  
Clinical Investigations ◽  
Length Polymorphisms ◽  
Polymerase Chain

The discipline of pharmacogenetics will continue to expand as scientific and clinical investigations increase our understanding of genetic variabilities in drug metabolism and response. These research efforts will include determination of molecular mechanisms for the different polymorphisms and evaluation of their clinical significance. The availability of molecular methodologies such as restriction fragment length polymorphisms analysis, polymerase chain reaction, and expression of cDNAs in cell cultures will further the investigative work in detection of normal and mutant alleles, identification of new substrates for different polymorphic metabolizing enzymes, and evaluation of mechanisms of individual susceptibility to biological disorders. Other areas such as the role of pharmacogenetics in drug development and regulatory control, in evaluation of potential drug-drug interactions, ethnic variation in polymorphic metabolism, and response, also need to be evaluated.

Characterization of sleep-wake patterns in a novel transgenic mouse line overexpressing human prepro-orexin/hypocretin

2010 ◽  
Vol 198 (3) ◽  
pp. 237-249 ◽  
Author(s):  
K. A. Mäkelä ◽  
H.-K. Wigren ◽  
J. C. Zant ◽  
T. Sakurai ◽  
L. Alhonen ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Wake Patterns
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