Growth In Semen Research Articles

Evaluation of the effect of conventional and natural antifungals on motility and kinetics of cooled stallion semen.

Microbial growth in semen may cause a decline of sperm quality and fertility; however, the addition of antifungals to semen extender has been shown to impair the overall fertility of the sperm. The aim of this study was to evaluate the antifungal activity of conventional and natural compounds, and their effect on the motility and kinetics of cooled stallion semen. A total of 15 ejaculates from five stallions were collected using the artificial vagina. Each ejaculate was supplemented with: fluconazole at 12.5 (F1), 25 (F2) and 50 (F3) mg/ml; amphotericin-B at 6.5 (A1), 12.5 (A2) and 25 (A3) mg/ml (A3); clotrimazole at 12.5 (C1), 25 (C2) and 50 (C3) mg/ml; isoespintanol at 50 (I1), 100 (I2) and 150 (I3) µM; thymol at 50 (T1), 100 (T2) and 150 (T3) µM; and a control without supplementation. Motility and kinetics of semen at 0, 24 and 48hr of cooling at 15°C were assessed using computer-assisted sperm analysis (CASA). At hour 48 of cooling, the antifungal effect of the treatments was evaluated. At hour 0 of cooling, amphotericin-B and I3 showed a reduction in most of the motility and kinetic parameters evaluated (p<.05). These treatments, and also C2 and C3, showed similar results at 24 and 48hr of cooling. Thymol maintained motility and kinetics of the spermatozoa at all evaluated refrigeration times. Besides, I2 showed a decrease (p<.05) in the colony-forming unit compared to that in the control. It is concluded that thymol and isospintanol could be added as natural antifungals in extenders for stallion semen refrigeration.

Calcium and pH interaction limits bloom formation and expansion of a nuisance microalga

AbstractMicroalgal range expansions are increasing in frequency and magnitude but generally remain unnoticed until mass development occurs. Gonyostomum semen is a freshwater raphidophyte that causes nuisance blooms in lakes and has recently expanded its distribution across Europe. G. semen was considered to mainly occur in humic lakes in the boreal region but is now found in high density also in other freshwater habitats on a larger geographic scale with growing incidence. In this study, we focused on which environmental factors limit its expansion. Our hypothesis was that G. semen occurs in many different lake types, except for high alkalinity lakes, in which high pH in combination with high calcium concentration would inhibit its growth. Results from our field study illustrate the environmental heterogeneity of G. semen bloom sites across Europe and the United States. Nevertheless, none of these sites combined high pH and high calcium concentration. In a mesocosm study, as well as a laboratory experiment, we further demonstrated that growth of G. semen is inhibited in conditions combining both high pH and high calcium concentration. We also discuss the function of Sphagnum peat mosses in rendering an alkaline habitat suitable to G. semen growth. Our study highlights that high alkalinity environments act as a major colonization barrier to G. semen. While this finding explains which environmental filters limit G. semen distribution it also helps in understanding its current expansion. With globally decreasing calcium concentrations in freshwater ecosystems, new habitats have and will become conducive to G. semen growth.

The role of nutrients in promoting a bloom of the nuisance raphidophyte species Gonyostomum semen in a subtropical reservoir

The nuisance raphidophyte Gonyostomum semen (Ehrenberg) Diesing blooms in lakes and is known to produce a mucilage which can cause human skin irritation. Parameters such as water temperature, iron and high dissolved organic matter loads are shown to be important drivers in temperate regions. However, the causes of blooms in warmer latitudes are less well understood. Over a 6 mo study period, we used field monitoring and a nutrient addition experiment within a water reservoir to examine the role of nutrients in promoting G. semen growth. Early in the study, an inflow event delivered nutrients which increased dissolved inorganic nitrogen (DIN) concentrations 2-fold and filterable reactive phosphorus (FRP = phosphate) 4-fold. This event shifted the phytoplankton community from a mixed community to one dominated by G. semen. Two months after the inflow event, the effect of nutrients in promoting G. semen was confirmed with a nutrient addition experiment. Total biovolumes of this species across the study were strongly predicted by FRP and nitrate + nitrite concentrations. G. semen biovolumes also decreased as ratios of total nitrogen (TN):total phosphorus (TP) and DIN:FRP increased, highlighting the importance of P inputs. The stable isotope tracer 15N-nitrate was also used to trace N through the G. semen-dominated phytoplankton community. The tracer rapidly cycled through the G. semen-dominated phytoplankton community in 1-2 d, settled and remineralized, providing an ongoing source of DIN for maintaining blooms. Overall, the results highlight the importance of FRP, and to a lesser extent nitrate, in promoting blooms of this nuisance species.

Synthesis, Characterization and Evaluation of Ceftriaxone Mediated BSA Microparticles (CTR–BSA) as a Cryoprotective Agent for Preserving Human Sperm

Infections caused by bacteria may have the potential to regress spermatogenesis, hinder seminal tract and damage sperm. Genital tract infections accounts for 15% of infertility cases among males. Semen extenders supplemented with antimicrobial protein conjugates are used in artificial insemination for the purpose of cryopreserving sperm cells against residual bacterial load and for enhancing the longevity of sperm in in vitro conditions. In this study, an antibiotic mediated protein microparticle was synthesized and analyzed for its antibacterial activity, cytotoxic and genotoxic effects. Ceftriaxone mediated BSA microparticles (CTR–BSA) were prepared by incubating BSA with ceftriaxone (CTR) followed by the intermittent addition of ethanol. Characterization of the microparticle was done using infrared and UV–visible spectroscopy, scanning electron microscope and energy dispersive X-ray and zeta potential analysis. The drug loading efficiency and entrapment efficiency of the microparticle were recorded as 68% and 75% respectively. Continuous dialysis method was performed to check the cumulative percentage of CTR released. Sperm immobilizing capacity of Escherichia coli was confirmed by co-incubating the sperm cells with 24 h grown E. coli culture. In vitro studies of the microparticle at different concentrations were carried out to check its antibacterial activity and cytotoxicity. The microparticle was found to have high antibacterial activity against E. coli and less cytotoxic and genotoxic effects on sperm cells. Molecular docking analysis confirmed minimum binding energy and inhibition constant for the CTR–BSA complex. This study can be incorporated in the development of semen extenders to curb the problem of infectious microbial growth in semen.

The effects of antibiotic type and extender storage method on sperm quality and antibacterial effectiveness in fresh and cooled-stored stallion semen

Two experiments were conducted to evaluate the effects of antibiotic-containing extender of on sperm quality and control of bacterial growth. In Experiment 1, ejaculates were diluted in extender containing no antibiotics, potassium penicillin G-amikacin disulfate (PEN-AMIK), ticarcillin disodium-potassium clavulanate (TICAR-CLAV), piperacillin sodium/tazobactam sodium (PIP-TAZ), or meropenem (MERO). In freshly extended semen, only slight differences were detected among some antibiotic treatments for total sperm motility, curvilinear velocity, and viable acrosome-intact sperm (P < 0.05). In cool-stored semen, slight differences were also detected among certain antibiotic treatments for curvilinear velocity and chromatin integrity (P < 0.05). In Experiment 2, ejaculates were diluted in extender and subjected to no bacterial spiking, or inoculated with lower or higher doses of K. pneumoniae or P. aeruginosa. Following cooled storage of semen, colony forming units/ml (CFU/mL) were less in PEN-AMIK (706 ± 244) and MERO (1576 ± 1076) treatment groups than in TICAR-CLAV (4678 ± 1388) or PIP-TAZ (8108 ± 3198) treatment groups (P < 0.05). The CFU/mL were lower in all antibiotic-containing treatment groups than the control group (18478 ± 4374; P < 0.05). The percentage of culture plates containing no bacterial growth in unspiked semen was greater in PEN-AMIK (75%) than PIP-TAZ (15%) or TICAR-CLAV (20%; P < 0.05). The percentages of culture plates containing no bacterial growth in semen spiked with a lower doses of K. pneumoniae or P. aeruginosa were higher in PEN-AMIK (70% and 50%, respectively) then in all other treatment groups (0–40% and 0–15% for K. pneumonia and P. aeruginosa, respectively; P < 0.05); however, complete control of bacterial load was only modest even with PEN-AMIK. In both experiments, freezing and thawing extender prior to use did not have any appreciable detrimental effect on sperm quality or antibiotic efficacy. In summary, all antibiotics tested had minimal effects on measures of sperm quality in fresh or cool-stored semen extenders; however, PEN-AMIK, followed by MERO, yielded the best results in terms of antimicrobial efficacy. None of the antibiotic types controlled bacterial growth, in comparison with the antibiotic-free control group, when extended semen was spiked with a high concentration of Pseudomonas aeruginosa. Cooled storage of extended semen reduced bacterial growth in comparison with freshly extended semen.

Control Methods and Evaluation of Bacterial Growth on Fresh and Cooled Stallion Semen

The penis and prepuce of the stallion have a high bacterial load on its surface, forming a natural microbial flora that contaminates the semen during ejaculation. Bacterial growth in semen may cause a decline on sperm quality, viability, and fertility and predisposes the occurrence of endometritis in inseminated mares. Thus, the aim of this study was to evaluate the effect of penile wash before semen collection, the addition of different commercial skim milk–based extenders containing antibiotics (BotuSemen and INRA96), and the removal of seminal plasma by filtration on the quality, viability, and bacterial proliferation on fresh and cooled stallion semen. Animals that were never submitted to penile wash before semen collection tended to have lower bacterial contamination in the ejaculate. Semen samples extended in BotuSemen showed superiority in total motility, progressive motility, average path velocity, and rapid sperm and lower bacterial contamination in relation to semen samples extended in INRA96 after 24 hours of cooling. No difference was found in these parameters between the storage temperatures (5°C and 15°C). Furthermore, the removal of seminal plasma by filtration reduced the bacterial load in semen after cooling. In conclusion, the penile wash before semen collection tended to reduce the bacterial growth in fresh semen. The use of a semen extender with appropriate antibiotics and removal of seminal plasma by filtration were effective in reducing the bacterial contamination and preserved the quality of cooled stallion semen.

Cell lysis of competitors and osmotrophy enhance growth of the bloom-forming alga Gonyostomum semen

Abstract in Undetermined The nuisance alga Gonyostomum semen (Raphidophyceae) is known to form dense blooms in many freshwater bodies, and has increased its distribution and abundance. However, information on the mechanisms behind bloom formation and maintenance is scarce. Field observations indicate that G. semen may be favored in humic lakes, In the present study, we performed controlled laboratory experiments on cultures to test whether G. semen growth is enhanced by humic acids. In addition, we tested the mixotrophic capability of G. semen by providing it with Rhodomonas lacustris as prey. G. semen increased its growth rate in the presence of humic substances due to either acquisition of carbon or some unknown growth factor. Moreover, growth rate was enhanced in the presence of R. lacustris, which in turn was negatively influenced when cultured together with G. semen. We found no evidence of phagotrophy, but observed lysis of R. lacustris cells exposed to G. semen pre-grown with R, lacustris. Thus, our experiments suggest that cell lysis (probably via trichocyst action) and osmotrophy could be 2 mechanisms involved in establishing and maintaining dominance of G. semen in humic lakes. (Less)

Effect of bovine seminal plasma on bacterial membranes

The effect of bovine seminal plasma (BSP) on membrane function in BSP-sensitive and BSP-resistant bacteria was studied using Bacillus megaterium and Micrococcus lysodeikticus as sensitive strains and Pseudomonas aeruginosa as a resistant strain. In the presence of BSP the sensitive bacteria rapidly lost 14C-aminoisobutyric acid, a non-metabolisable analogue of glycine and alanine; leakage of cytoplasmic material occurred and 14C-valine was not accumulated. The BSP-resitant pseudomonad did not release as much cytoplasmic material and was able to accumulate valine in the presence of BSP. Osmotically sensitive bodies prepared from sensitive or resistant bacteria were equally sensitive to lysis by BSP. It is concluded that BSP inhibits bacterial growth in semen by damaging the integrity of bacterial cytoplasmic membranes. The factor responsible may be identical with a factor in BSP which is reported to increase the fragility of spermatozoa. In Gram-negative bacteria an outer permeability barrier may block the access of inhibitory factors in BSP to the cytoplasmic membrane and thus confer resistance.