Effect Of Hydrostatic Pressure Treatment Research Articles

Effects of Hydrostatic Pressure Treatment of Newly Fertilized Eggs on the Ploidy Level and Karyotype of Pikeperch Sander lucioperca (Linnaeus, 1758).

We studied the effect of different magnitudes (7000 PSI (48.26 MPa), 8000 PSI (55.16 MPa), and 9000 PSI (62.05 MPa)) of hydrostatic pressure on the ploidy of pikeperch larvae. Pressure shock was applied 5 min after the fertilization of eggs at a water temperature of 14.8 ± 1 °C. A 7000 PSI pressure shock was applied for 10 or 20 min, while 8000 and 9000 PSI treatments lasted for 10 min. Each treatment with its respective control was completed in triplicate, where different females’ eggs served as a replicate. In the treatment groups exposed to 7000 PSI for 10 min, only diploid and triploid larvae were identified, while 2n/3n mosaic individuals were found after a 20-min exposure to a 7000 PSI pressure shock. The application of 8000 or 9000 PSI pressure shocks resulted in only triploid and mosaic individuals. Among larvae from eggs treated with 8000 PSI, three mosaic individuals with 2n/3n karyotype were identified (4.0 ± 6.9%), while a single (2.0 ± 3.5%) 1n/3n mosaic individual was found in the 9000 PSI-treated group. To our knowledge, this is the first report that demonstrates the induction of a haplo-triploid karyotype by hydrostatic pressure shock in teleost fish. The dominance of triploid individuals with a reasonable survival rate (36.8 ± 26.1%) after 8000 PSI shock supports the suitability of the hydrostatic pressure treatment of freshly fertilized eggs for triploid induction in pikeperch.

Development of new methods for increasing the germination of licorice (Glycyrrhiza uralensis Fisch.) seeds: preliminary data

The licorice (Glycyrrhiza uralensis Fisch.) is cultivated as a valuable medicinal plant. It is grown from seeds, but 70-90% of its seeds are in deep physical dormancy (hard seeds) – do not swell and do not germinate without special treatment (scarification). We are searching for the most effective methods of such processing. We have studied the effect of hydrostatic pressure from 10 to 40 MPa (pressure treatment) on the licorice seeds to improve the swelling and germination of them, which belong to a pair of visually distinguished groups by the color of the seed coat. For the first time, it was found that olive-colored seeds do not germinate after pressure treatment (the number of hard seeds is 80% or more). At the same time, very high content (up to 90%) of swollen but non-viable seeds was detected in the group with a light brown color of the seed coat. Hydrostatic pressure levels used did not significantly reduce hard seeds proportion in studied licorice seed material. A weak positive effect of hydrostatic pressure treatment was found. Further search for optimal pressure treatment modes for licorice seeds germination increasing looks promising.

Cytological studies on induced mitogynogenesis in Japanese flounder Paralichthys olivaceus (Temminck et Schlegel).

The effect of hydrostatic pressure treatment on the induction of mitogynogenesis in the eggs of Japanese flounder Paralichthys olivaceus (Temminck et Schlegel) by using heterospecific sperm were studied. Before treatment, the eggs were at metaphase of the first mitosis. The spindle was disassembled by the treatment and then resembled in its pretreatment position, and the chromosomes were rearranged, i.e., the first mitosis was not blocked. During the second mitotic cycle, only a monopolar spindle was assembled in each blastomere and the chromosomes doubled, but cell cleavage was blocked. In the third cycle, mitosis proceeded normally with a bipolar spindle in each blastomere. Flow cytometric analysis of ploidy demonstrated that mitogynogenetic larvae were all diploid. The ultraviolet light-irradiated sperm of the red sea bream (Pagrus major) was condensed, formed a dense chromatin body, and randomly entered one blastomere.

Controlled hydrostatic pressure stress downregulates the expression of ribosomal genes in preimplantation embryos: a possible protection mechanism?

The efficiency of various assisted reproductive techniques can be improved by preconditioning the gametes and embryos with sublethal hydrostatic pressure treatment. However, the underlying molecular mechanism responsible for this protective effect remains unknown and requires further investigation. Here, we studied the effect of optimised hydrostatic pressure treatment on the global gene expression of mouse oocytes after embryonic genome activation. Based on a gene expression microarray analysis, a significant effect of treatment was observed in 4-cell embryos derived from treated oocytes, revealing a transcriptional footprint of hydrostatic pressure-affected genes. Functional analysis identified numerous genes involved in protein synthesis that were downregulated in 4-cell embryos in response to hydrostatic pressure treatment, suggesting that regulation of translation has a major role in optimised hydrostatic pressure-induced stress tolerance. We present a comprehensive microarray analysis and further delineate a potential mechanism responsible for the protective effect of hydrostatic pressure treatment.

Effect of hydrostatic pressure treatment on the structure–foaming relationships of β-lactoglobulin

The effect of hydrostatic pressure treatment (150 and 250 MPa) on the structure and foaming characteristics of dimeric β-lactoglobulin (β-LG) at pH 7.0 is investigated. Angle- and concentration-dependent dynamic light scattering is used to probe pressure-induced changes in size under ambient conditions. The cumulant method is used to analyze correlation functions of the dynamic light scattering experiments and to estimate hydrodynamic radii and the width of their distribution. Instead of a decrease, hydrodynamic radii slightly increase after pressure treatment and depend on protein concentration. Both native and pressurized samples are almost free of aggregates as indicated by a small polydispersity index, PDI < 0.25. A small fraction of larger aggregates in the native sample is not affected by the pressure treatment and only bias the scattering signal at low scattering angles. Circular dichroism measurements indicate transformation of the secondary structure into a random coil for the pressurized samples. Only slightly unfolded β-LG stabilizes foam best because the largest effect is observed for samples treated with 150 MPa. Pressure-modified β-LG could have the potential to be used as a stabilizer in the food industry because of the low pressure needed during processing.

Comprehensive study of hydrostatic pressure treated human umbilical cord blood cells via response surface method

Amelioration of the survival parameters of cryopreserved samples after thawing has already been addressed through several techniques including vitrification to avoid the formation of ice cores. However, this approach cannot be followed in the case of samples with higher volumes. Hydrostatic pressure (HP) treatment has been proven to increase some qualifying parameters (e.g., motility, insemination efficiency) of certain biological samples. Accordingly, the preparation of umbilical cord blood (UCB) samples through an active (mechanical) pre-stressing process to increase the survival rate of cryopreserved samples can be regarded as a novel strategy that calls for basic experimental studies. The goal of our study was to assess the effects of HP treatment on the qualifying parameters (DNA fragmentation by agarose gel electrophoresis and capillary electrophoresis, Total Nucleotide Cell (TNC) count, CD34+/CD45+ count, and superoxide dismutase activity (SOD) of human umbilical cord blood (UCB) derived cells). The experimental arrangement was set to provide data for response-surface analysis to take into account the common effects of the individual variables of pressure and time exposure. 3D visualization of experimental data revealed that 50-min long HP treatment at 12.5MPa can significantly (α=0.05) enhance white blood cell (WBC) and CD34+/CD45+ cell counts. However no DNA fragmentation was observed even at higher pressures, SOD activity was triggered over 15.0MPa. As a conclusion, HP treatment may contribute to the optimal cryopreservation of UCB cells by significantly increasing WBC and CD34+/CD45+ cell counts without adverse effects neither on DNA stability nor on triggering SOD activity.

Potential mechanism involved in removal of hydrophobic pesticides from vegetables by hydrostatic pressure

In our previous study, we found that the removal rate of hydrophobic pesticide on cherry tomatoes shows the maximum by hydrostatic pressure treatment (HPT) around 75MPa. The objective of this study was to investigate the causes of reduction in the removal rate above 75MPa HPT. Separating cuticle from flesh of the cherry tomatoes after HPT and examining the pesticide residues in each part the following was found: the detectable pesticide amount in the flesh part showed little change from the non-treated samples. Ethanol was applied as the surrounding solution during pressurization so as to prevent the reattachment of pesticide and decrease water solubility, and removal efficiency declined little. The effect of HPT on removal rate time indicated no significant difference at 0.1MPa, the optimum level to be at 75MPa for a comparatively short time, and at 400MPa removal rate increased with time.

Fundamental study on the effect of hydrostatic pressure treatment on the bread-making performance of oat flour

The effect of hydrostatic pressure (HP) has been investigated on cereal starches, proteins and flour systems, but its efficacy in cereal food processing has not been established. This study describes the use of HP as a tool to improve the bread-making performance of oat flour. For this purpose, oat batters were HP-treated at 200, 350 or 500 MPa, and the microstructure was investigated using scanning electron microscopy and bright field microscopy. Furthermore, HP-treated oat batters were added to an oat-bread recipe, replacing 10, 20 or 40% of untreated oat flour. Breads analysis revealed significantly improved bread volume upon addition of 10% oat batter treated at 200 MPa. The staling rate was reduced of all breads containing oat batter treated at 200 MPa. In contrast, bread quality deteriorated due to addition of oat batters treated at pressures ≥350 MPa, independent of the addition level. Overall, weakening of the protein structure, moisture redistribution and possibly changed interactions between proteins and starch were responsible for the positive effects of HP-treatment at 200 MPa on the bread-making performance of oat flour. Protein network formation and pre-gelatinisation of starch did not improve oat-bread quality.

High hydrostatic pressure treatment improves the quality of in vitro-produced ovine blastocysts

Exposure to sub-lethal hydrostatic pressure (HP) treatment is emerging as an approach to improve the general resistance of gametes and embryos to in vitro conditions. The present study was aimed to evaluate the effect of HP treatment on in vitro-produced ovine blastocysts. Experiment 1 was aimed to define optimal treatment parameters: two different HP treatments were applied to blastocysts and embryo survival was evaluated. In Experiment 2, HP parameters (40 MPa, 70 min, 38 °C) selected in Experiment 1 were used to treat blastocysts. Embryo quality was assessed and compared with untreated controls by counting total cell number, the inner cell mass (ICM) and trophectoderm (TE) cells and by evaluating nuclear picnosis. HP-treated blastocysts were processed for gene expression analysis (AQP3, ATP1A1, BAX, CDH1, HSP90β, NANOG, OCT4 and TP53) 1, 5h after the end of HP exposure. Results showed that the hatching rate of embryos treated at 40 MPa was significantly higher than that of the 60 MPa-treated group (P<0.01) and similar to untreated embryos. Blastocysts exposed at 40 MPa showed higher ICM (P<0.05) and TE (P<0.01) cell number and a lower percentage of picnotic nuclei (P<0.05) compared with the control group. Significantly lower abundance for BAX (P<0.01) and OCT4 (P<0.05) transcripts were observed in HP embryos than in the control group. In conclusion, treatment with HP improved the quality of in vitro-produced ovine blastocysts by increasing their cell number and reducing the proportion of nuclear picnosis.

The effect of hydrostatic pressure treatment on the protein profile of boar spermatozoa before and after freezing

The effect of hydrostatic pressure treatment on the protein profile of boar spermatozoa before and after freezing

Effect of high pressure gaseous carbon dioxide on the germination of bacterial spores

Effect of high pressure gaseous carbon dioxide treatment (HGCT) at 6.5 MPa, 35 °C on the germination of bacterial spores was investigated. Germination of bacterial spores was estimated by the decrease of heat tolerance. Approximately, 40% of Bacillus coagulans and 70% of Bacillus licheniformis were germinated by HGCT for 120 min at 35 °C, respectively. Germination was confirmed by phase contrast microscopy. The effect of hydrostatic pressure treatment (HPT) at 6.5 MPa, 35 °C on the germination of B. coagulans and B. licheniformis spores were also investigated. Spores did not germinate by HPT alone at 6.5 MPa for 120 min.

Inactivation of Vegetative Bacteria by Rapid Decompression Treatment

ABSTRACT: We investigated the inactivation and injury effects of hydrostatic pressure treatment combined with a slow decompression (SD treatment) and a rapid decompression (RD treatment) on several vegetative bacterial strains. Single decompression time for the SD and RD treatments was longer than 30 s and about 1 ms, respectively. The RD treatment gave significantly (P &lt; 0.05) smaller D and z values than the SD treatment, showing that the RD treatment was more effective than the SD treatment in inactivating vegetative bacteria and in lowering the treatment pressure. It was suggested that a rapid decompression procedure could enhance the degree of pressure‐mediated injury, which caused the higher bactericidal effect of the RD treatment.

Effects of Hydrostatic Pressure-Treatment and Allylisothiocyanate Addition on Quality of Grated Yam Soup

For the purpose of development of grated yam (Dioscorea opposita Thunb.) soup with high viscosity and low survival fraction of bacteria, effects of hydrostatic pressure-treatment and addition of allylisothiocyanate (AIT) on the quality of grated yam soup were examined. 1) The viscosity of grated yam dropped with hot water treatments (over 80°C) remarkably. The survival fraction of bacteria did not decrease with hot water treatments of the temperature (under 70°C) that the viscosity of grated yam did not drop. 2) The more AIT that was added, the higher the effect of decrease of bacteria became. The effect of decrease of bacteria was confirmed at AIT 0.005ml/100g. There change of color of the grated yam soup with the addition of AIT under 0.02ml/100g. 3) On the condition of hydrostatic pressure-treatment, the effect of decrease with 700 MPa pressure condition was higher than that with 400 MPa pressure condition. By combining hydrostatic pressure-treatment and the addition of AIT, the survival fraction of bacteria was reduced even more. 4) There was only a slight change of viscosity of grated yam soup with hydrostatic pressure-treatments. However, with 700 MPa pressure condition at 50°C, the viscosity of grated yam soup was reduced. The change of b (yellow) value of color was confirmed with 700 MPa pressure condition. With 700 MPa pressure condition at 20°C or 50°C, b value decreased slightly.

Cytogenetic effects of hydrostatic pressure treatment to suppress the first cleavage of salmon embryos

Tetraploids in chum and masu salmon were induced by suppressing the first cleavage by hydrostatic pressure of 680 kg/cm 2. Ploidy level was scored by counting nucleoli using silver-stained preparations. True tetraploids were induced in some chum embryos treated at 13.2 h after fertilization; however, aneuploids or polyploid mosaics were also found. These showed abnormal embryogenesis. Chromosomes isolated from the nucleus or precociously moving to the centrosome were observed in the dividing cells. Chromosome bridges between two centrosomes were also observed, as well as chromosome fragments, rings and gaps. Even if damages induced by mitotic suppression with hydrostatic pressure treatment is minor at the first cleavage, it will be amplified through rapid cell cycles.