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Membrane Integrity (membrane + integrity)
Kinds of Membrane Integrity Selected AbstractsEffect of Different Concentrations of Ascorbic Acid on Motility, Membrane Integrity and Chromatin Status of Frozen-Thawed Canine Spermatozoa Within Six Hours of Storage at 37°CREPRODUCTION IN DOMESTIC ANIMALS, Issue 2009K Eulenberger Contents The aim of this study was to examine comprehensively the effect of ascorbic acid (Asc) on frozen-thawed canine semen. Pooled ejaculates (n = 10) were assessed for quality with a computer-assisted sperm analyser (CASA). After centrifugation, the semen was divided into four aliquots (A,D) of which three were diluted with Uppsala 1 extender (v/v) containing different concentrations of Asc (B: 6.8 mmol/l; C: 13 mmol/l; D: 27 mmol/l). One group without Asc served as control (A). Subsequently, dilution samples were treated and cryopreserved as described previously (Theriogenology 66, 2006, 173). After thawing, samples were stored at 37°C for 1, 3 and 6 h, then examined for quality (CASA, flow cytometry, sperm chromatin structure assay; SCSA). Staining for flow cytometry was performed with FITC-PNA and propidium iodide (Reproduction 128, 2004, 829). The SCSA was performed with both Tris-NACL-EDT buffer (TNE)- and Tris-fructose-citrate buffer (TFC). In the Asc-supplemented groups, percentages of progressively motile sperm (P) were significantly lower than in the control group (A 1 h: 56.6 ± 9.8, 6 h: 18 ± 4.5; B 1 h: 51.2 ± 11.8, 6 h: 13.6 ± 5; C 1 h: 41 ± 16.2, 6 h: 11.2 ± 6.1; D 1 h: 37 ± 15.2, 6 h: 8.6 ± 5; p < 0.01), whereas, the percentages of intact cells without acrosome reactions did not differ between groups (p > 0.05). Furthermore, there were no significant differences between TNE- and TFC-samples, for ,T, for SD of ,T or for comp ,T [comp ,T: TCF-A: 2.5 ± 1.7%, TNE-A: 3.4 ± 3.2%; TCF-D: 2.5 ± 2%, TNE-D: 3.3 ± 4.3%; p > 0.05]. However, samples diluted with both extenders correlated concerning ,T, but not comp ,T. We therefore recommend using TNE-buffer for SCSA with cryopreserved canine semen. In addition, the average ,T values did not differ significantly between the controls and all other groups (TNE-A: 380.2 ± 89.1; TNE-D: 338.1 ± 137.4; p > 0.05). It can be concluded that addition of Asc to cryoextender does not increase quality of frozen-thawed canine semen. [source] Toxicity of lead in aqueous medium to Desulfovibrio desulfuricans G20ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2003Rajesh K. Sani Abstract The toxicity of Pb(II) to sulfate-reducing bacteria (SRB) was studied using Desulfovibrio desulfuricans G20 in a medium specifically designed to assess metal toxicity. The effects of Pb(II) toxicity were observed in terms of longer lag times, lower specific growth rates, and in some cases no measurable growth. With an increase in medium pH from 6 to 8, Pb(II) toxicity decreased. At all pH values, in the presence of Pb(II) concentrations ranging from 3 to 15 ,M, specific growth rates decreased and lag times increased. The minimum inhibiting concentration (MIC) of Pb(II) causing a complete inhibition in growth at pH 6 was 10 ,M, as compared to 15 ,M at pH 7.2 and 8. These MIC values are 40 times lower than previously reported for SRB. Results also show that with increases in initial cell protein concentration (inoculum size), soluble Pb(II) removal rates increased and the degree to which Pb(II) caused increased lag times was reduced. In the presence of Pb(II), in all cases in which D. desulfuricans grew (even after a 312-h lag time), the final cell protein concentration was equivalent to that of the Pb-free control. Live/dead staining, based on membrane integrity, indicated that while Pb(II) inhibited growth, Pb(II) did not cause a loss of D. desulfuricans membrane integrity. [source] Freeze-and-thaw-disrupted tumour cells impair the responsiveness of DC to TLR stimulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2008Iñigo Tirapu Abstract Cancer immunotherapy aims at inducing immune responses against tumour-associated antigens that mediate the eradication of tumour cells. For successful vaccination against antigens expressed by the tumour, the immune system has to be provided with sufficient amounts of these antigens in connection with strong immunostimulatory signals such as toll-like receptor (TLR) ligands. Tumour cells represent a convenient source of relevant tumour-associated antigens but can have suppressive properties. In this study, we explored how different forms of tumour cell material influence the activation of dendritic cells (DC), which play a crucial role in the induction of anti-tumour immune responses. We show that freeze-and-thaw-disrupted tumour cells inhibit DC activation in response to TLR stimulation, a phenomenon that is only partially seen with non-disrupted control cells. This suppression of DC stimulation is independent of tumour cell- and species-specific factors. We tested the hypothesis that phosphatidylserine on cells with disrupted membrane integrity mediates inhibition of TLR-induced DC activation. Our experimental evidence indicates that phosphatidylserine is not involved in the inhibition of TLR-mediated DC activation by freeze-and-thaw-disrupted cells. The inhibitory activity associated with disrupted tumour cells could explain why such preparations are less effective tumour vaccines than apoptotic tumour cells. [source] IL-7 inhibits dexamethasone-induced apoptosis via Akt/PKB in mature, peripheral T cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2003Hadassah Sade Abstract We have investigated the mechanism of IL-7-mediated inhibition of dexamethasone-induced apoptosis in T cells. Broad-spectrum caspase inhibitors block dexamethasone-triggered nuclear fragmentation, but not the loss of mitochondrial transmembrane potential or membrane integrity in CD3+ mature T cells isolated from adult mouse spleens. IL-7 blocked dexamethasone-induced apoptosis and the processing of caspase-3 and caspase-7. IL-7 also blocked dexamethasone-triggered dephosphorylation of the serine-threonine kinase Akt/PKB and its target, the Ser136 residue in Bad. The loss of anti-apoptotic proteins Bcl-xL and inhibitor of apoptosis protein-2 (IAP-2) was also blocked by IL-7. The protective effect was attenuated by pharmacological inhibitors of phosphatidylinositol-3 kinase (PI3K) with one exception: inhibition of PI3K did not abrogate Bcl-xL expression in the presence of IL-7. The anti-apoptotic role of Akt suggested by these experiments was tested by overexpression of constitutively active Akt, which blocked dexamethasone-induced apoptosis and elevated IAP-2 but not Bcl-xL levels in a mature T cell line. Thus, IL-7 regulates IAP-2 expression and inhibits dexamethasone-induced apoptosis by activating Akt via PI3K-dependent signaling, but regulates Bcl-xL expression via a PI3K-independent pathway in mature T cells. [source] Involvement of mitochondrial signaling pathways in the mechanism of Fas-mediated apoptosis after spinal cord injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Wen Ru Yu Abstract Activation of the Fas receptor has been recently linked to apoptotic cell death after spinal cord injury (SCI). Although it is generally considered that Fas activation mediates apoptosis predominantly through the extrinsic pathway, we hypothesized that intrinsic mitochondrial signaling could be involved in the underlying mechanism of Fas-induced apoptosis after SCI. In the present study, we utilized the FejotaTM clip compression model of SCI at T5,6 in C57BL/6 Fas-deficient (lpr) and wild-type mice. Complementary studies were conducted using an in vitro model of trauma or a Fas-activating antibody to induce apoptosis in primary neuronal,glial mixed spinal cord cultures. After in vivo SCI, lpr mice, in comparison with wild-type mice, exhibited reduced numbers of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells at the lesion, reduced expression of truncation of Bid (tBid), apoptosis-inducing factor, activated caspase-9 and activated caspase-3, and increased expression of the antiapoptotic proteins Bcl-2 and Bcl-xL. After in vitro neurotrauma or the induction of Fas signaling by the Jo2 activating antibody, lpr spinal cord cultures showed an increased proportion of cells retaining mitochondrial membrane integrity and a reduction of tBid expression, caspase-9 and caspase-3 activation, and TUNEL-positive cells as compared to wild-type spinal cord cultures. The neutralization of Fas ligand (FasL) protected against traumatically induced or Fas-mediated caspase-3 activation and the loss of mitochondrial membrane potential and tBid expression in wild-type spinal cord cultures. However, in lpr spinal cord cultures, FasL neutralization had no protective effects. In summary, these data provide direct evidence for the induction of intrinsic mitochondrial signaling pathways following Fas activation after SCI. [source] The surface-associated elongation factor Tu is concealed for antibody binding on viable pneumococci and meningococciFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2008Jan Kolberg Abstract Proteome analyses revealed that elongation factor-Tu (EF-Tu) is associated with cytoplasmic membranes of Gram-positive bacteria and outer membranes of Gram-negative bacteria. It is still debatable whether EF-Tu is located on the external side or the internal side of the membranes. Here, we have generated two new monoclonal antibodies (mAbs) and polyclonal rabbit antibodies against pneumococcal EF-Tu. These antibodies were used to investigate the amount of surface-exposed EF-Tu on viable bacteria using a flow cytometric analysis. The control antibodies recognizing the pneumococcal surface protein A and phosphorylcholine showed a significant binding to viable pneumococci. In contrast, anti-EF-Tu antibodies did not recognize pneumococcal EF-Tu. However, heat killing of pneumococci lacking capsular polysaccharides resulted in specific antibody binding to EF-Tu and, moreover, increased the exposure of recognized phosphorylcholine epitopes. Similarly, our EF-Tu-specific antibodies did not recognize EF-Tu of viable Neisseria meningitidis. However, pretreatment of meningococci with ethanol resulted in specific antibody binding to EF-Tu on outer membranes. Importantly, these treatments did not destroy the membrane integrity as analysed with control mAbs directed against cytoplasmic proteins. In conclusion, our flow cytrometric assays emphasize the importance of using viable bacteria and not heat-killed or ethanol-treated bacteria for surface-localization experiments of proteins, because these treatments modulate the cytoplasmic and outer membranes of bacteria and the binding results may not reflect the situation under physiological conditions. [source] Leptin and leptin receptor in human seminal plasma and in human spermatozoaINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2003T. Jope Summary Leptin, a 167 amino acid peptide, is known to influence the gonads via direct and indirect effects. Recent studies provide contradictory proposition about the peripheral impact of leptin in the male gonads. Thus, we examined leptin and its receptors in human seminal plasma and in human ejaculated spermatozoa by Western blot technique and fluorescence microscopy. In seminal plasma we found a free leptin band (16 kDa) by an anti-leptin polyclonal antibody. Incubation of seminal plasma with recombinant leptin caused a statistically significant increase in the amount of free leptin (p < 0.01) and supports this finding. Furthermore, a soluble leptin receptor (145 kDa) was found in human seminal plasma in the same specimen. We also detected a 145-kDa leptin receptor isoform in ejaculated spermatozoa as a possible target of leptin action in the male genital tract, which was localized at the tail of spermatozoa by immunofluorescence microscopy only. This receptor was significantly associated with the intactness of sperm plasma membranes. Spermatozoa with deteriorated membranes contained 49.2 ± 6.9% leptin receptor signal intensity compared with spermatozoa having intact membranes (p < 0.01). This finding is difficult to interpret and may be caused by a leakage of OB-R due to loss of membrane integrity. In conclusion, these data provide further hints for a peripheral role of leptin in the male genital tract, possibly, by an interaction between leptin and spermatozoa via sperm leptin receptors. [source] Effect of pentoxifylline on motility and membrane integrity of cryopreserved human spermatozoaINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2002P. Stanic The purpose of this study was to examine the effects of pentoxifylline used before and after semen cryopreservation,thawing on sperm motility and membrane integrity. Twenty-four semen samples were split into four equal aliquots. Aliquots were incubated at 37 °C for 30 min, followed by cryopreservation with TEST-yolk freezing medium using slow programmable freezing protocol. After 2 weeks the sperm samples were thawed, washed twice in Quinn's Sperm Washing Medium (modified HTF with 5.0 mg/mL Human Albumin) and incubated at 37 °C for 30 min. Aliquots were treated by adding 3 mmol/L pentoxifylline to: (1) fresh sperm samples during incubation period prior to cryopreservation, (2) sperm samples as a supplement to the cryoprotectant prior to cryopreservation, and (3) thawed sperm samples during incubation period. One aliquot received no treatment (control group). The addition of 3 mmol/L pentoxifylline to fresh semen during incubation period prior to cryopreservation significantly decreased progressive and total motility compared with controls. However, the addition of 3 mmol/L pentoxifylline to cryopreserved semen after thawing significantly increased progressive and total motility compared with controls. After post-thaw, no differences in motion characteristics between sperm samples treated by adding 3 mmol/L pentoxifylline as a supplement to the cryoprotectant and control groups were observed. Post-thaw hypoosmotic swelling (HOS) test scores did not improve with the addition of pentoxifylline compared with the control group. It is concluded that pentoxifylline enhanced post-thaw motility of cryopreserved human spermatozoa when added after thawing. No improvement was found by freezing sperm with pentoxifylline. [source] Different Patterns of Physiological and Molecular Response to Drought in Seedlings of Malt- and Feed-type Barleys (Hordeum vulgare)JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2010M. Rapacz Abstract A number of physiological and molecular characteristics are proposed as selection criteria for drought tolerance. This study measured the associations between physiological and molecular characteristics of drought response in malting and fodder spring barleys. Plants of 13 malt- and 14 feed-type Polish genotypes were exposed to drought at the four-leaf stage for 7 days. Drought susceptibility indexes (DSI) were calculated for membrane integrity, water status, gas exchange and PSII photochemical activity. Accumulation of HVA1 and SRG6 transcripts in drought was measured with real-time PCR. A wide range of variation in the drought response was observed among studied genotypes. Malting barleys were less sensitive to drought than feed-barleys according to all the traits studied. In both groups, different patterns of relationships between traits were observed. In malting genotypes only, CO2 assimilation rates in drought, as well as PSII efficiency were related to both water content and the accumulation of HVA1 transcript in leaves. On the other hand the SRG6 expression was highly correlated in both groups of barley with the photochemical efficiency of PSII. The results suggest that different physiological, biochemical and molecular characteristics should be applied in the selection towards drought resistance in the case of malting and fodder barleys. [source] Heterogeneity in chlorine susceptibility for Legionella pneumophila released from Acanthamoeba and HartmannellaJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2009C.-W. Chang Abstract Aims:, To assess chlorine susceptibility of Legionella pneumophila grown from two amoebic hosts, Acanthamoeba castellanii and Hartmannella vermiformis. Methods and Results:, After being released from amoebae, Leg. pneumophila were chlorinated at 2 and 5 mg l,1 for 5 min,24 h. Bacterial culturability and cytoplasmic membrane deterioration were quantified by culture assay on BCYE, agar and BacLight stains coupled with a fluorescent microscope, respectively. Chlorination reduced the culturability of Leg. pneumophila by 2·93,4·59 log CFU ml,1 and damaged cellular membrane by 53·8,99·2%. Moreover, cells released from H. vermiformis exhibited significantly lower degrees in culturability reduction (P = 0·0008) and membrane deterioration (P < 0·0001) when compared with those from A. castellanii. The amoebic genus is the most significant parameter affecting cytoplasmic membrane integrity of chlorinated Legionella (P < 0·0001), followed by free chlorine concentration (P = 0·042). Conclusions:,Legionella pneumophila replicated from H. vermiformis possess greater chlorine resistance than the cells from A. castellanii. Significance and Impact of the Study:, This study shows the heterogeneity of amoebae-grown Leg. pneumophila in chlorine susceptibility, which should be considered in the control of legionellae proliferation, particularly in the systems where H. vermiformis is dominant, e.g. hot water plumbing. [source] Volume recovery, surface properties and membrane integrity of Lactobacillus delbrueckii subsp. bulgaricus dehydrated in the presence of trehalose or sucroseJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007E.E. Tymczyszyn Abstract Aims:, Although the practical importance of adding sugars before drying is well known, the mechanism of protection of bacteria by sugars is not clear. The response of the dehydrated micro-organisms to rehydration is analysed in terms of structural and functional changes, and correlated with their potentiality to grow in rich media. These aspects are related with the membrane integrity and the metabolic state of the rehydrated bacteria, measured by means of surface properties and permeability. To attain this objective, Lactobacillus delbrueckii subsp. bulgaricus was dehydrated in the presence and in the absence of sucrose and trehalose. The bacterial response upon rehydration was investigated by determining: (i) the lag time of the bacterial growing in rich media, (ii) the restoration of the surface properties and the cellular volume and (iii) the membrane integrity. Methods and Results:,Lactobacillus delbrueckii subsp. bulgaricus was grown in MRS at 37°C overnight [De Man et al. (1960)J Appl Bacteriol 23, 130] and then dehydrated for 10, 20 and 30 min at 70°C in a vacuum centrifuge. The lag time of micro-organisms was determined by optical density changes after rehydration. The surface properties were determined by measuring the zeta potential of the bacteria suspended in aqueous solution. The cellular volume recovery was measured, after stabilization in saline solution, by light scattering and by the haematocrit method [Alemohammad and Knowles (1974)J Gen Microbiol 82, 125]. Finally, the membrane integrity has been determined by using specific fluorescent probes [SYTO 9 and propidium iodide, (PI)] that bind differentially depending on the integrity of the bacterial membrane. The lag time of Lact. delbrueckii subsp bulgaricus, dehydrated by heat in the presence of sucrose or trehalose and after that rehydrated, was significantly shortened, when compared with that obtained for bacteria dried in the absence of sugars. In these conditions, trehalose and sucrose maintained the zeta potential and the cell volume close to the control (nondried) cells. However, the membrane integrity, measured with fluorescent probes, was maintained only when cells were dehydrated for 10 min in the presence of sugars. For larger times of dehydration, the membrane integrity was not preserved, even in the presence of sugars. Conclusions:, When the micro-organisms are dehydrated in the absence of protectants, the membrane damage occurs with a decrease in the absolute value of the zeta potential and a decrease in the cellular volume recovered after rehydration. In contrast, when the zeta potential and the cellular volume are restored after rehydration to that corresponding to nondried cells, the micro-organisms are able to recover and grow with a reduced lag time. This can only be achieved when the dehydration is carried out in the presence of sugars. At short dehydration times, the response is associated with the preservation of the membrane integrity. However, for longer times of dehydration the zeta potential and volume recovery occurs in the presence of sugars in spite of a severe damage at membrane level. In this condition, cells are also recovered. In conclusion, to predict the ability of growing after dehydration, other bacterial structural parameters besides membrane integrity, such as zeta potential and cellular volume, should be taken into account. Significance and Impact of the Study:, The correlation of the lag time with the surface and permeability properties is of practical importance because the correlation of these two parameters with cell viability, allow to determine the potential bacterial capacity to grow in a rich medium after the preservation procedure, without necessity of performing a kinetic curve of growth, which is certainly time-consuming. [source] Statins, stem cells, and cancerJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2009Kalamegam Gauthaman Abstract The statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) were proven to be effective antilipid agents against cardiovascular disease. Recent reports demonstrate an anticancer effect induced by the statins through inhibition of cell proliferation, induction of apoptosis, or inhibition of angiogenesis. These effects are due to suppression of the mevalonate pathway leading to depletion of various downstream products that play an essential role in cell cycle progression, cell signaling, and membrane integrity. Recent evidence suggests a shared genomic fingerprint between embryonic stem cells, cancer cells, and cancer stem cells. Activation targets of NANOG, OCT4, SOX2, and c-MYC are more frequently overexpressed in certain tumors. In the absence of bona fide cancer stem cell lines, human embryonic stem cells, which have similar properties to cancer and cancer stem cells, have been an excellent model throwing light on the anticancer affects of various putative anticancer agents. It was shown that key cellular functions in karyotypically abnormal colorectal and ovarian cancer cells and human embryonic stem cells are inhibited by the statins and this is mediated via a suppression of this stemness pathway. The strategy for treatment of cancers may thus be the targeting of a putative cancer stem cell within the tumor with specific agents such as the statins with or without chemotherapy. The statins may thus play a dual prophylactic role as a lipid-lowering drug for the prevention of heart disease and as an anticancer agent to prevent certain cancers. This review examines the relationship between the statins, stem cells, and certain cancers. J. Cell. Biochem. 106: 975,983, 2009. © 2009 Wiley-Liss, Inc. [source] Chromium (VI) inhibits heme oxygenase-1 expression in vivo and in arsenic-exposed human airway epithelial cellsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2006Kimberley A. O'Hara Inhaled hexavalent chromium (Cr(VI)) promotes lung injury and pulmonary diseases through poorly defined mechanisms. One hypothesis for this lung pathogenesis is that Cr(VI) silences induction of cytoprotective genes, such as heme oxygenase-1 (HO-1), whose total lung mRNA levels were reduced 21 days after nasal instillation of potassium dichromate in C57BL/6 mice. To investigate the mechanisms for this inhibition, Cr(VI) effects on basal and arsenic (As(III))-induced HO-1 expression were examined in cultured human bronchial epithelial (BEAS-2B) cells. An effect of Cr(VI) on the low basal HO-1 mRNA and protein levels in BEAS-2B cells was not detectible. In contrast, Cr(VI) added to the cells before As(III), but not simultaneously with As(III), attenuated As(III)-induced HO-1 expression. Transient transfection with luciferase reporter gene constructs controlled by the full length ho-1 promoter or deletion mutants demonstrated that this inhibition occurred in the E1 enhancer region containing critical antioxidant response elements (ARE). Cr(VI) pretreatment inhibited As(III)-induced activity of a transiently expressed reporter construct regulated by three ARE tandem repeats. The mechanism for this Cr(VI)-attenuated transactivation appeared to be Cr(VI) reduction of the nuclear levels of the transcription factor Nrf2 and As(III)-stimulated Nrf2 transcriptional complex binding to the ARE cis element. Finally, exposing cells to Cr(VI) prior to co-exposure with As(III) synergized for apoptosis and loss of membrane integrity. These data suggest that Cr(VI) silences induction of ARE-driven genes required for protection from secondary insults. The data also have important implications for understanding the toxic mechanisms of low level, mixed metal exposures in the lung. J. Cell. Physiol. 209: 113,121, 2006. © 2006 Wiley-Liss, Inc. [source] EFFECT OF COMBINED UNDERWATER PROCESSING AND MILD PRECUT HEAT TREATMENT ON THE SENSORY QUALITY AND STORAGE OF FRESH-CUT CANTALOUPE MELONJOURNAL OF FOOD QUALITY, Issue 4 2010KAREN L. BETT-GARBER ABSTRACT Improvement of storage quality of fresh-cut cantaloupe using a combination precut heat treatment and a modified underwater cutting treatment was determined. Eating quality was evaluated using descriptive sensory analysis, and fruit integrity was measured with respiration, cell leakage and product weight loss. Treatments included (1) control (no treatment); (2) making the first longitudinal cut underwater; (3) mild precut heat treatment in a water bath at 60C for 60 min; and (4) combination of precut heat treatment and the underwater cutting methods. Precut heating and processing underwater resulted in more intense fruity/melon flavor compared to conventional processed fresh-cut fruit. Reduced electrolyte leakage and enhanced membrane integrity were observed in all three experimental treatments, as evidenced by lower conductivity measurements. The underwater cut and combined treatments significantly reduced respiration during fresh-cut storage, reflecting less physical stress and membrane damage. Weight loss was not significantly affected by any treatment during fresh-cut storage. PRACTICAL APPLICATIONS There is a steady increase in the consumption of fresh-cut produce. To enhance the storage quality of fresh-cut cantaloupe melon, two minimal processing techniques were examined separately and combined. The methods are mild heat treatment of the whole melon at 60C for 60 min then cooling to 4C for 24 h, cutting the cantaloupe in half and removing the seeds while submerged in a calcium chloride and water solution, and the combination of the two treatments. These methods are simple and can be utilized by small or large processors to maintain sensory quality and fruit integrity during storage. [source] Onion Cells After High Pressure and Thermal Processing: Comparison of Membrane Integrity Changes Using Different Analytical Methods and Impact on Tissue TextureJOURNAL OF FOOD SCIENCE, Issue 7 2010Maria E. Gonzalez Abstract:, Two different analytical methods were evaluated for their capacity to provide quantitative information on onion cell membrane permeability and integrity after high pressure and thermal processing and to study the impact of these processing treatments on cell compartmentalization and texture quality. To determine changes in cell membrane permeability and/or integrity the methodologies utilized were: (1) measurement of a biochemical product, pyruvate, formed as a result of membrane permeabilization followed by enzymatic activity and (2) leakage of electrolytes into solution. These results were compared to previously determined methods that quantified cell viability and 1H-NMR T2 of onions. These methods allowed for the monitoring of changes in the plasma and tonoplast membranes after high pressure or thermal processing. High pressure treatments consisted of 5 min holding times at 50, 100, 200, 300, or 600 MPa. Thermal treatments consisted of 30 min water bath exposure to 40, 50, 60, 70, or 90 °C. There was strong agreement between the methods in the determination of the ranges of high pressure and temperature that induce changes in the integrity of the plasma and tonoplast membranes. Membrane rupture could clearly be identified at 300 MPa and above in high pressure treatments and at 60 °C and above in the thermal treatments. Membrane destabilization effects could already be visualized following the 200 MPa and 50 °C treatments. The texture of onions was influenced by the state of the membranes and was abruptly modified once membrane integrity was lost. Practical Application:, In this study, we used chemical, biochemical, and histological techniques to obtain information on cell membrane permeability and onion tissue integrity after high pressure and thermal processing. Because there was strong agreement between the various methods used, it is possible to implement something relatively simple, such as ion leakage, into routine quality assurance measurements to determine the severity of preservation methods and the shelf life of processed vegetables. [source] Defining the membrane proteome of NK cellsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2010Dhimankrishna Ghosh Abstract The present study was initiated to define the composition of the membrane proteome of the Natural Killer (NK) like cell line YTS. Isolated membranes were treated with reagents that have been reported to remove peripheral membrane proteins. Additional steps involving trifluoroethanol (TFE) were introduced in an effort to remove remaining nonintegral membrane proteins. This treatment resulted in the release of a subset of proteins without any apparent disruption of membrane integrity. The membranes were solubilized and digested with trypsin in 25% TFE. The resulting peptides were separated using an off-line two-dimensional reversed phase LC technique at alkaline and acidic pHs. Mass spectrometric analysis identified 1843 proteins with high confidence scores. On the basis of the presence of transmembrane regions or evidence of posttranslational modifications and prediction algorithms, approximately 40% of the identified proteins were predicted as plausible membrane proteins. The remaining species were largely involved in cellular processes and molecular functions that could be predicted to be transiently associated with membranes. The analytical approaches presented in this study offer robust generic methods for the identification and characterization of membrane proteins. These observations highlight the fact that the membrane is a dynamic entity that is composed of integral and stably associated proteins. Copyright © 2009 John Wiley & Sons, Ltd. [source] Human laminin-332 degradation by Candida proteinasesJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2008P. Pärnänen Background:, Human laminin-332 (Lm-332) degradation by 12 Candida strains and effects of synthetic proteinase inhibitors [Ilomastat (ILM), EDTA, chemically modified tetracycline-3(CMT-3), CMT-308, synthetic peptide CTT-2, and Pefabloc] were studied. Materials and methods:, Laminin-332 was incubated with sonicated cell fractions and 10 times concentrated cell-free fractions of reference and clinical strains of C. albicans, C. dubliniensis, C. guilliermondii, C. glabrata, C. krusei, and C. tropicalis. Proteolysis, pH effects, and inhibitors were analyzed by fluorography and zymography. Results:, Cell fractions of all species except C. guilliermondii and cell-free fractions of C. albicans, and C. dubliniensis showed 20,70 kDa gelatinases at pH 5.0 and 6.0. At pH 7.6, C. glabrata, C. krusei, and C. tropicalis cell fractions and C. tropicalis cell-free fractions showed 55,70 kDa gelatinases. CMT-3, CMT-308, and CTT-2 inhibited Candida gelatinases slightly better than Pefabloc, ILM, and EDTA. No Candida fractions degraded Lm-332 at pH 7.6, but at pH 5.0, 100 kDa bands were generated by cell fractions of C. dubliniensis and C. tropicalis; C. albicans and C. glabrata clinical strains; and C. guilliermondii reference strain. C. krusei reference strain yielded three 100,130 kDa bands. C. albicans, C. dubliniensis, and C. tropicalis reference and clinical strain's cell-free fractions generated 100 kDa band. Conclusions:, Laminin-332 degradation is pH-dependent and differences exist between studied Candida strains. Lm-332 degradation can exert functional disturbances on basement membrane integrity, possibly aiding Candida cell invasion into tissues. Certain synthetic matrix metalloproteinase inhibitors (CMTs, CTT) can inhibit Candida proteinases and may be therapeutically useful in future. [source] Expression of human ,-defensins-1 and -2 peptides in unresolved chronic periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 4 2004Qian Lu Background:, Human ,-defensins (hBDs) are antimicrobial peptides which contribute to host innate immunity by disrupting the membrane integrity of a broad spectrum of microorganisms. Objectives:, This study aimed to determine the expression profiles of hBD-1 and -2 peptides in gingiva and to assess the possible relations of these antimicrobial peptides with periodontal health and disease. Methods:, Seven periodontally healthy subjects and 22 patients with unresolved chronic periodontitis were recruited and the gingival biopsies collected consisted of healthy tissues from the healthy subjects (HT-C); periodontal pocket tissues (PoT) and inflamed connective tissues (ICT) from the base of pocket, i.e. granulation tissues, as well as clinically healthy tissues (HT-P) from the adjacent clinically healthy sites from the patients. The expression of hBD-1 and -2 peptides was detected by immunohistochemistry and quantitatively analyzed with a computerized image processing system. Results:, Both hBD-1 and -2 peptides were detected in all periodontally healthy subjects, while hBD-1 was detected in all patients and hBD-2 was found in most of the patients. Their expression was mainly confined to the granular and spinous layers of gingival epithelium, in which hBD-1 was detected in both intercellular spaces and cytoplasm, whereas hBD-2 was mainly observed in the cytoplasm. HT-C expressed significantly higher levels of hBD-2 than HT-P (p < 0.05). Within the patients, both defensins were up-regulated significantly in PoT as compared with the adjacent HT-P (p < 0.05). Conclusions:, The present study showed that hBD-1 and -2 were frequently expressed in the granular and spinous layers of gingival epithelia and their expression may be associated with periodontal health and disease. [source] Effects of Chronic Alcohol Abuse on Alveolar Epithelial Barrier Function and Glutathione HomeostasisALCOHOLISM, Issue 7 2003Ellen L. Burnham Background: An association between the development and severity of the acute respiratory distress syndrome has been described in individuals who abuse alcohol chronically, possibly through a mechanism involving the deficiency of pulmonary glutathione. In a rodent model of chronic alcohol abuse, this antioxidant contributes to the maintenance of alveolar-capillary membrane integrity. We postulated that humans who chronically abuse alcohol will have similar alterations in alveolar-capillary barrier function. Methods: Bronchoalveolar lavage was performed in 18 healthy chronic alcoholics and 18 control subjects; total protein and glutathione concentrations were measured within the epithelial lining fluid. To examine possible protracted effects of alcohol abuse, a subset of 11 chronic alcoholic subjects underwent a second bronchoalveolar lavage after a week of abstinence. Results: Chronic alcoholic subjects had significantly elevated protein concentrations compared with controls (8.64 ,g protein/ng immunoglobulin A vs. 5.91 ,g protein/ng immunoglobulin A, p= 0.01). After a week of abstinence, no significant increase in either the glutathione levels or normalization of the protein concentrations in the epithelial lining fluid was demonstrable. Conclusions: Increased protein levels in the epithelial lining fluid of individuals who abuse alcohol chronically may signify abnormal alveolar epithelial barrier function that does not appear to readily reverse after a period of abstinence. [source] Ethanol Effects on Nitric Oxide Production in Cerebral Pial CulturesALCOHOLISM, Issue 4 2001Chin-Lung Shih Background: Although alcohol abusers are known to have higher incidences of hemorrhagic cerebrovascular diseases, it is not known whether these changes are associated with ethanol (EtOH) action on nitric oxide (NO) production in the cerebrovascular cells. The purpose of this study was to examine the effects of EtOH treatment on basal and cytokine-induced NO production in cortical pial cultures. Methods: Cell cultures for this study included murine primary pial vascular cells, primary glial cells and cortical neurons. These cells were exposed to cytokines or EtOH for 24 to 48 hr. The culture media were used for measurement of nitrite, as an indication for NO release, and lactate dehydrogenase (LDH), as an index of cell membrane integrity. In addition, immunocytochemical determinations were carried out to identify cell types and to assess inducible nitric oxide synthase (iNOS). Results: Exposure of primary pial vascular cultures to cytokines that consisted of interleukin-1, (IL-1,; 250 pg/mL) and interferon-, (IFN,; 2 ng/mL) or to EtOH (50 to 100 mM) for 24 to 48 hr significantly elevated NO production. NO production could be attenuated by N -nitro-L-arginine (N-arg), a nonspecific NOS inhibitor, or aminoguanidine (AG), an iNOS inhibitor. Increased iNOS immunoreactivity was observed in cytokines- or EtOH-treated pial cells. When pial cells were cocultured with cortical neurons, prolonged EtOH exposure led to a large increase in NO production as well as LDH release. However, this increase was not observed in pial culture alone or in mixed cortical culture. Nevertheless, inhibition of NO production with N-arg or AG did not alter the EtOH-induced LDH release in the pial cells cocultured with cortical neurons. Conclusion: These results show that EtOH exposure led to increased production of NO in primary pial cell culture. In mixed culture that contained cortical neurons and pial cells, EtOH induced increase in NO as well as LDH release, which is an indication of loss of cell membrane integrity. However, EtOH-mediated LDH release in mixed cortical pial cultures was not a consequence of the increase in NO production by these cells. Studies that use mixed cortical-pial cultures may provide a unique in vitro system for examining the interactions among glial cells, neurons, and cerebrovascular cells. [source] Impact of hot water treatment on sprouting, membrane permeability, sugar content and chip colour of reconditioned potato tubers following long-term cold storageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2008Marios C Kyriacou Abstract BACKGROUND: The efficacy of hot water treatment in facilitating successful reconditioning of processing potato (Solanum tuberosum L.) cultivar Hermes following 6 months cold storage at 4.5 °C was examined. Tubers were subjected to hot water treatments (HWTs) at 52.5, 55.0, 57.5 and 60.0 °C for 0,60, 0,50, 0,40 and 0,20 min, respectively, and then reconditioned for 20 days at 16 °C before evaluated for sprouting, fresh weight loss, membrane permeability, sugar content and processing quality. RESULTS: The study demonstrates that in order to achieve complete inhibition of sprouting during potato reconditioning HWTs must exceed the thermal tolerance threshold of the tubers. Short-duration HWT was effective in retarding sprout growth and tuber dehydration without significantly affecting storage parenchyma membrane permeability, tuber sugar content or processing quality. On the contrary, prolonged HWT caused extensive heat damage, loss of membrane integrity and induced an increase in tuber sucrose and reducing sugar content resulting in deterioration of chip colour in proportion to treatment duration. CONCLUSION: Although HWT at 52.5,60 °C following long-term cold storage did not improve the processing quality of potato tubers after 20 days of reconditioning, future work is needed to evaluate the effect of short-duration HWT on the permissible extent of reconditioning and subsequent processing quality. Copyright © 2008 Society of Chemical Industry [source] Effects of femtosecond laser irradiation on osseous tissuesLASERS IN SURGERY AND MEDICINE, Issue 3 2007B. Girard DMD Abstract Background and Objective Few studies have investigated femtosecond (fs) lasers for cutting bone tissue. Study Design/Materials and Methods A 775 nm, 1 kHz, 200 femtosecond, up to 400 µJ laser system was used to irradiate in vitro calcified cortical bone samples and bone tissue culture samples. Results The ablation threshold in cortical bone was 0.69±0.08 J/cm2 at 775 nm and 0.19±0.05 J/cm2 at 387 nm. Plasma shielding experiments determined that the ablation plume and the plasma significantly affect material removal at high repetition rates and appear to generate thermal transients in calcified tissue. Confocal analysis revealed intact enzymatic activity on the surface of cells immediately adjacent to cells removed by fs laser irradiation. Conclusions These experiments demonstrate that fs lasers used for bone tissue cutting do not appear to generate significant temperature transients to inactivate proteins and that cellular membrane integrity is disrupted for only a few cell layers. Lasers Surg. Med. 39:273,285, 2007. © 2007 Wiley-Liss, Inc. [source] Cellular response mechanisms in Pseudomonas aeruginosa PseA during growth in organic solventsLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2009R. Gaur Abstract Aims:, Solvent-tolerant bacteria have emerged as a new class of micro-organisms able to grow at high concentrations of toxic solvents. Such bacteria and their solvent-stable enzymes are perceived to be useful for biotransformations in nonaqueous media. In the present study, the solvent-responsive features of a lipase,producing, solvent-tolerant strain Pseudomonas aeruginosa PseA have been investigated to understand the cellular mechanisms followed under solvent-rich conditions. Methods and Results:, The solvents, cyclohexane and tetradecane with differing log P -values (3·2 and 7·6 respectively), have been used as model systems. Effect of solvents on (i) the cell morphology and structure (ii) surface hydrophobicity and (iii) permeability of cell membrane have been examined using transmission electron microscopy, atomic force microscopy and other biochemical techniques. The results show that (i) less hydrophobic (low log P -value) solvent cyclohexane alters the cell membrane integrity and (ii) cells adapt to organic solvents by changing morphology, size, permeability and surface hydrophobicity. However, no such changes were observed in the cells grown in tetradecane. Conclusions:, It may be concluded that P. aeruginosa PseA responds differently to solvents of different hydrophobicities. Bacterial cell membrane is more permeable to less hydrophobic solvents that eventually accumulate in the cytoplasm, while highly hydrophobic solvents have lesser tendency to access the membrane. Significance and Impact of the Study:, To the best of our knowledge, these are first time observations that show that way of bacterial solvent adaptability depends on nature of solvent. Difference in cellular responses towards solvents of varying log P -values (hydrophobicity) might prove useful to search for a suitable solvent for carrying out whole-cell biocatalysis. [source] Morphological changes in mouse embryos cryopreserved by different techniquesMICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2007A.R.S. Coutinho Abstract Cryopreservation of mammalian embryos is an important tool for the application of reproductive biotechnologies. Subjective evaluation to determine embryo viability is often used. The determination of the best cryopreservation protocol depends on morphological and molecular analysis of cellular injuries. The main objective of this study was to compare two methods of cryopreservation by assessing morphological alterations of frozen embryos using light, fluorescence, and transmission electron microscope. Fresh (control), slow frozen, and vitrified mouse embryos were composed. To evaluate the viability of the embryos, the cell membrane integrity was assessed using Hoechst33342 and propidium iodide (H/PI) staining. Morphological analyses using hematoxylin and eosin (HE) staining were performed to test different techniques (in situ, paraffin, and historesin) by both light and fluorescence microscopy. Transmission electron microscope was used to detect ultrastructural alterations in Spurr- and Araldite-embedded samples. H/PI staining detected more membrane permeability in the vitrification (69.8%) than in the slow freezing (48.4%) or control (13.8%) groups (P < 0.001). Historesin-embedded samples showed to be more suitable for morphological analyses because cellular structures were better identified. Nuclear evaluation in historesin sections showed the induction of pycnosis in slow freezing and vitrification groups. Cytoplasm evaluation revealed a condensation and an increase in eosinophilic intensity (indicating apoptosis) in the slow freezing group, and weakly eosinophilic structures and degenerated cells (indicating oncosis) in the vitrification group (P < 0.05). Ultrastructural analyses confirmed HE morphological findings. It was concluded that both cryopreservation techniques resulted in oncosis and apoptosis injuries. However, vitrification caused more severe cellular alterations and reduced embryonic viability compared to slow freezing. Microsc. Res. Tech., 2007. © 2006 Wiley-Liss, Inc. [source] Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coliMOLECULAR MICROBIOLOGY, Issue 1 2009Goran Jovanovic Summary The phage shock protein (Psp) system found in enterobacteria is induced in response to impaired inner membrane integrity (where the Psp response is thought to help maintain the proton motive force of the cell) and is implicated in the virulence of pathogens such as Yersinia and Salmonella. We provided evidence that the two-component ArcAB system was involved in induction of the Psp response in Escherichia coli and now report that role of ArcAB is conditional. ArcAB, predominantly through the action of ArcA regulated genes, but also via a direct ArcB,Psp interaction, is required to propagate the protein IV (pIV)-dependent psp -inducing signal(s) during microaerobiosis, but not during aerobiosis or anaerobiosis. We show that ArcB directly interacts with the PspB, possibly by means of the PspB leucine zipper motif, thereby allowing cross-communication between the two systems. In addition we demonstrate that the pIV-dependent induction of psp expression in anaerobiosis is independent of PspBC, establishing that PspA and PspF can function as a minimal Psp system responsive to inner membrane stress. [source] Hutchinson-Gilford progeria syndrome: oral and craniofacial phenotypesORAL DISEASES, Issue 3 2009DL Domingo Objective:, Hutchinson-Gilford progeria syndrome (HGPS) is a rare early-onset accelerated senescence syndrome. In HGPS, a recently identified de novo dominant mutation of the lamin A gene (LMNA) produces abnormal lamin A, resulting in compromised nuclear membrane integrity. Clinical features include sclerotic skin, cardiovascular and bone abnormalities, and marked growth retardation. Craniofacial features include ,bird-like' facies, alopecia, craniofacial disproportion, and dental crowding. Our prospective study describes dental, oral soft tissue, and craniofacial bone features in HGPS. Methods:, Fifteen patients with confirmed p.G608G LMNA mutation (1,17 years, seven males, eight females) received comprehensive oral evaluations. Anomalies of oral soft tissue, gnathic bones, and dentition were identified. Results:, Radiographic findings included hypodontia (n = 7), dysmorphic teeth (n = 5), steep mandibular angles (n = 11), and thin basal bone (n = 11). Soft tissue findings included ogival palatal arch (n = 8), median sagittal palatal fissure (n = 7), and ankyloglossia (n = 7). Calculated dental ages (9 months to 11 years 2 months) were significantly lower than chronological ages (1 year 6 months to 17 years 8 months) (P = 0.002). Eleven children manifested a shorter mandibular body, anterior/posterior cranial base and ramus, but a larger gonial angle, compared to age/gender/race norms. Conclusion:, Novel oral-craniofacial phenotypes and quantification of previously reported features are presented. Our findings expand the HGPS phenotype and provide additional insight into the complex pathogenesis of HGPS. [source] Enhanced Bactericidal Activity of Modified Titania in Sunlight against Pseudomonas aeruginosa, a Water-Borne PathogenPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2010S. Swetha Photocatalyst-mediated inactivations generate reactive oxygen species and OH radicals, which induce oxidative destruction of membrane integrity, causing damage to membrane phospholipids of gram negative bacteria like Pseudomonas aeruginosa. Nanosized TiO2 was synthesized by gel to crystalline conversion and Zr-doped TiO2 was synthesized by pulverization using appropriate precursor. The doped nanocrystals retained the anatase phase with a marginal increase in crystallite size, averaging at 25 nm. SEM,EDX analysis of the doped sample depicts the substantial growth of grain size with 1.33 atomic weight % of zirconium. The created electron states in the doped sample act as charge carrier traps suppressing recombination which later detraps the same to the surface of the catalyst causing enhanced interfacial charge transfer. Zr-doped TiO2 at the molecular scale exhibits better photocatalytic activity with lower bandgap energy that can respond to visible light. The redshift caused by the dopants in absorption spectra of TiO2 facilitated the nonintrinsic sample to exhibit nearly 2-fold enhancement of photoinactivation in sunlight. Extent of photoinactivation of P. aeruginosa was observed to be complete (100%) within 150 min of sunlight exposure in the presence of modified TiO2. [source] Ultraviolet B Light-induced Nitric Oxide/Peroxynitrite Imbalance in Keratinocytes,Implications for Apoptosis and NecrosisPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Shiyong Wu Elevation of nitric oxide (NO,) can either promote or inhibit ultraviolet B light (UVB)-induced apoptosis. In this study, we determined real-time concentration of NO, and peroxynitrite (ONOO,) and their role in regulation of membrane integrity and apoptosis. Nanosensors (diameter 300,500 nm) were used for direct in situ simultaneous measurements of NO, and ONOO, generated by UVB in cultured keratinocytes and mice epidermis. An exposure of keratinocytes to UVB immediately generated ONOO, at maximal concentration of 190 nm followed by NO, release with a maximal concentration of 91 nm. The kinetics of UVB-induced NO,/ONOO, was in contrast to cNOS agonist stimulated NO,/ONOO, from keratinocytes. After stimulating cNOS by calcium ionophore (CaI), NO, release from keratinocytes was followed by ONOO, production. The [NO,] to [ONOO,] ratio generated by UVB decreased below 0.5 indicating a serious imbalance between cytoprotective NO, and cytotoxic ONOO,,a main component of nitroxidative stress. The NO,/ONOO, imbalance increased membrane damage and cell apoptosis was partially reversed in the presence of free radical scavenger. The results suggest that UVB-induced and cNOS-produced NO, is rapidly scavenged by photolytically and enzymatically generated superoxide (O2,,) to produce high levels of ONOO,, which enhances oxidative injury and apoptosis of the irradiated cells. [source] Insights into the cellular mechanisms of desiccation tolerance among angiosperm resurrection plant speciesPLANT CELL & ENVIRONMENT, Issue 11 2004M. VICRÉ ABSTRACT Water is a major limiting factor in growth and reproduction in plants. The ability of tissues to survive desiccation is commonly found in seeds or pollen but rarely present in vegetative tissues. Resurrection plants are remarkable as they can tolerate almost complete water loss from their vegetative tissues such as leaves and roots. Metabolism is shut down as they dehydrate and the plants become apparently lifeless. Upon rehydration these plants recover full metabolic competence and ,resurrect'. In order to cope with desiccation, resurrection plants have to overcome a number of stresses as water is lost from the cells, among them oxidative stress, destabilization or loss of membrane integrity and mechanical stress. This review will mainly focus on the effect of dehydration in angiosperm resurrection plants and some of the strategies developed by these plants to tolerate desiccation. Resurrection plants are important experimental models and understanding the physiological and molecular aspects of their desiccation tolerance is of great interest for developing drought-tolerant crop species adapted to semi-arid areas. [source] Effect of Ram Age on Structural and Functional Competence of Frozen,Thawed Spermatozoa in Dairy SheepREPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2010AG Lymberopoulos Contents The objectives of this study were to investigate the influence of ram age on structural and functional competence of frozen,thawed spermatozoa and to test the hypothesis that increasing number of sperm bound to the zona pellucida in vitro was associated with decreasing in vivo fertility of frozen semen. Rams were allocated into two groups. Each group consisted of five rams aged either 1,2 years (young) or 4,5 years (mature). Three successive ejaculates were collected from each ram using an artificial vagina. Only ejaculates of , 2.5 × 109 sperm/ml and 80% sperm progressive motility were pooled per ram, diluted with Bioxcell® medium and frozen in 0.25 ml straws. The end points of post-thawing semen evaluation were computer-assisted cell motility analysis, sperm capacitation (chlortetracycline assay), simultaneous assessment of plasma membrane integrity, mitochondrial membrane potential and condensation status of nucleus, per-cell analysis of lipid peroxidation using C11-BODIPY581/591, sperm-hemizona binding (HZB) ability and sperm fertility after laparoscopic insemination of ewes (n = 114) in the progestagen-synchronized oestrus. The results showed that mature rams had significantly lower values of sperm hyperactivated motility and peroxidized sperm, higher percentages of live non-capacitated sperm and sperm cells with intact plasma membrane, functional mitochondria and condensed chromatin, as well as, greater lambing rate and ewe prolificacy. Sperm HZB binding ability was higher (p < 0.05) for young than for mature rams. Significant correlations were found between number of spermatozoa bound to the zona pellucida and semen fertility (r = ,0.63 to ,0.71). In conclusion, mature rams have better semen quality and in vivo fertility than young rams. Cryocapacitation can be involved in decreasing ram semen fertility as evidenced by the high number of spermatozoa bound to the zona pellucida in vitro. [source] | |||||||||||||||||||