Computer aided boar semen motility analysis for cereulide detection in different food matrices
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Formation of spatial patterns of cells is a recurring theme in biology and often depends on regulated cell motility. Motility of the rod-shaped cells of the bacterium Myxococcus xanthus depends on two motility machineries, type IV pili (giving rise to S-motility) and the gliding motility apparatus (giving rise to A-motility). Cell motility is regulated by occasional reversals. Moving M. xanthus cells can organize into spreading colonies or spore-filled fruiting bodies, depending on their nutritional status. To ultimately understand these two pattern-formation processes and the contributions by the two motility machineries, as well as the cell reversal machinery, we analyse spatial self-organization in three M. xanthus strains: (i) a mutant that moves unidirectionally without reversing by the A-motility system only, (ii) a unidirectional mutant that is also equipped with the S-motility system, and (iii) the wild-type that, in addition to the two motility systems, occasionally reverses its direction of movement. The mutant moving by means of the A-engine illustrates that collective motion in the form of large moving clusters can arise in gliding bacteria owing to steric interactions of the rod-shaped cells, without the need of invoking any biochemical signal regulation. The two-engine strain mutant reveals that the same phenomenon emerges when both motility systems are present, and as long as cells exhibit unidirectional motion only. From the study of these two strains, we conclude that unidirectional cell motion induces the formation of large moving clusters at low and intermediate densities, while it results in vortex formation at very high densities. These findings are consistent with what is known from self-propelled rod models, which strongly suggests that the combined effect of self-propulsion and volume exclusion interactions is the pattern-formation mechanism leading to the observed phenomena. On the other hand, we learn that when cells occasionally reverse their moving direction, as observed in the wild-type, cells form small but strongly elongated clusters and self-organize into a mesh-like structure at high enough densities. These results have been obtained from a careful analysis of the cluster statistics of ensembles of cells, and analysed in the light of a coagulation Smoluchowski equation with fragmentation.
Myxococcus xanthus
Gliding motility
Collective motion
Reversion
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Previous research showed that the morphological study of boar sperm depending on the length of semen storage temperatures hypothermal and bioactive substances for use in the composition of the dilution media could highlight the role of these substances in the preservation of boar semen. If the media presence in the composition of boar semen dilution class of bioactive substances may be increased glycosides boar semen during storage at a temperature of 16-18oC until 6-7 days without reducing power of fecundant sperm.
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Dilution
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Summary. Spermatozoa were collected from the rat caput epididymidis by micropuncture and their motility assessed after dilution in physiological saline containing carnitine or related compounds. l(+)-Carnitine caused, 2 min after dilution, a transient stimulation of the motility of spermatozoa with low initial motility. No stimulatory effects were seen on spermatozoa which had high initial motility. The d-isomer inhibited the motility of spermatozoa with high initial motility after 2 min and all compounds tested appeared to inhibit, at 20 min after dilution, the motility of spermatozoa with high initial motility. Acetyl-l-carnitine and acetyl-d-carnitine stimulated the motility of spermatozoa with low initial motility. This study suggests that carnitine may be important in the development by spermatozoa of the potential for motility and also to maintain mature spermatozoa in a quiescent state.
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The bacterium Myxococcus xanthus has two motility systems: S motility, which is powered by type IV pilus retraction, and A motility, which is powered by unknown mechanism(s). We found that A motility involved transient adhesion complexes that remained at fixed positions relative to the substratum as cells moved forward. Complexes assembled at leading cell poles and dispersed at the rear of the cells. When cells reversed direction, the A-motility clusters relocalized to the new leading poles together with S-motility proteins. The Frz chemosensory system coordinated the two motility systems. The dynamics of protein cluster localization suggest that intracellular motors and force transmission by dynamic focal adhesions can power bacterial motility.
Myxococcus xanthus
Gliding motility
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This study examined the correlations between some sexual behaviour parameters and semen characteristics. Five mature crossbred boars were housed individually and were trained for semen collection using a dummy sow in a collection pen. Semen was collected twice weekly from each boar by the gloved-hand technique during the 4-week study period. Forty-three ejaculates were obtained from these experimental boars. The following individual sexual behaviour activities of the boars towards the dummy sow were recorded during semen collection time to first mount, time to penile extension, time to commencement of ejaculation, time from first mount to penile extension and duration of ejaculation. The correlations between sexual behaviour and semen characteristics and amomg the individual semen characteristics themselves were analysed. Positive correlations were found between the duration of ejaculation and total volume (r=0.42 P<0.01, n=43); and the gel free volume (r=0.44 P<0.01, n=43) and total sperm count in the ejaculate (r=0.38 P<0.05, n=43). A positive correlation was also found between the ejaculate volume and total sperm count (r=0.31 P<0.05, n=43). Large differences between and within boars in sexual behaviour and semen characteristic parameters were evident.
Ejaculation
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Semen collection
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ABSTRACT To examine the influence of boar exposure environment and daily movement on the efficacy of boar-induced precocious puberty in the gilt, 60 Large White × (Large White × Landrace) prepubertal gilts from 12 litters were randomly allocated within litter to five treatment groups of six, in two replicates, at 145 days of age. Treatments were (1) control (no movement or boar exposure), (2) gilts moved to a boar pen and exposed to a mature boar, (3) gilts moved to a different pen and exposed to a boar, (4) gilts moved to a different pen only, (5) gilts moved to a vacated boar pen. Treatments occurred for 30 min/day for 75 days, or until pubertal oestrus was observed. Gilts showing pubertal oestrus were removed and slaughtered. Ovaries were examined to confirm reproductive status. Gilts failing to exhibit oestrus by 240 days of age were slaughtered and nominally ascribed a pubertal age of 245 days. Age at puberty was significantly earlier ( P < 0·001) in treatments 2 and 3 involving boar exposure than in treatments 1, 4 and 5 not involving boar exposure. No significant difference was observed in the median gilt age at puberty between the two forms of boar exposure used in this experiment. Thus the efficacy of the boar effect does not appear to be significantly affected by the environment in which exposure to the boar takes place. Additionally, it is suggested that the stress of a daily pen change is insufficient to stimulate precocious puberty in gilts in the absence of boar contact.
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Wild boar
Large white
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Semen quality
Semen collection
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The aim of this study was to analyse the effect of filtration through Sephadex on the subpopulation characteristics of the boar semen. For this purpose 3 ml of 16 commercial doses of fresh diluted boar semen were filtered through a Sephadex G‐15/Polypropylene column. Motility parameters were analysed by a CASA system and statistical study was performed by SAS package using the VARCLUS and the FASTLUST procedures. Statistical study revealed four subpopulations in fresh boar semen, as previously had described (Theriogenology 61: 673–690).Total motility was higher in control than in filtered semen, but there were not statistical differences (65.63 ± 9.65 vs 41.40 ± 9.02). Moreover, the analysis did not show many changes neither in the characteristics nor in the distribution of the four subpopulations. As example although ALHmed of filtered samples were slightly higher, there were only significant differences (p < 0.001) in two subpopulations (subpopulation 2 : 2.2 ± 0.05 in control vs 2.7 ± 0.08 in filtered. Subpopulation 3 : 4.5 ± 0.11 in control vs 5.8 ± 0.23 in filtered semen). HME was also statistically different (p < 0.005) in one subpopulation, showing great values in filtered semen (1.7 ± 0.15 vs 3.0 ± 0.30). In conclusion, the filtration by Sephadex/Polypropylene column does not cause strong changes in subpopulation sperm distribution.
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Sephadex
Statistical Analysis
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