Procedure for bovine ICSI, not sperm freeze-drying, impairs the function of the microtubule-organizing center

This study was designed to investigate whether freeze-dried (FD) bull spermatozoa maintained the function of the microtubule-organizing center (MTOC) after rehydration and intracytoplasmic sperm injection (ICSI). In a preliminary attempt, the cleavage and blastocyst formation rates in FD-ICSI zygotes (36 and 1%, respectively) were found to be considerably lower than those in control ICSI zygotes (67 and 21%, respectively) or in IVF zygotes (78 and 43%, respectively). An alkaline comet assay indicated that the DNA fragmentation index (length of comet tail % DNA liberated) was not significantly different between fresh and FD spermatozoa. In the main experiment, formation of sperm-asters in the FD-ICSI oocytes 7 h postinsemination occurred at a similar rate when compared with the control ICSI oocytes (41 vs. 49%). Among the oocytes exhibiting sperm aster formation, the extent of microtubule network assembly was comparable between the FD-ICSI and control ICSI groups. However, the MTOC of the ICSI oocytes was not as functional as that of IVF oocytes in terms of the aster formation rate (97%) and the fluorescent intensity of the microtubule network (2.0 folds). These results suggest that the freeze-drying process per se had no adverse effect on maintaining the MTOC function in bull spermatozoa.     

Challenging endeavour for preservation of freeze-dried mammalian spermatozoa

Freeze-drying (lyophilization) has been proposed as an alternative method for sperm preservation to overcome the disadvantages of the current cryopreservation method such as the high maintenance cost of frozen stocks, the problems associated with transportation of frozen materials and the potential risk of total loss of the frozen stock. Since freeze-dried spermatozoa after rehydration lose their motility, which is an essential requirement to complete physiological fertilization, a relatively difficult microinsemination technique must be applied to rehydrated spermatozoa. Theoretically, it has been supposed that freeze-dried spermatozoa could maintain their functions and abilities to interact with the oocyte cytoplasm after prolonged storage at refrigerator temperature. However, sufficient yield of transferable blastocysts and production of live offspring derived from freeze-dried sperm samples are still subjects to be challenged and overcome in large domestic species.     

Distribution of the Water-Soluble Astaxanthin Binding Carotenoprotein (AstaP) in Scenedesmaceae

Photooxidative stress-inducible water-soluble astaxanthin-binding proteins, designated as AstaP, were identified in two Scenedesmaceae strains, Coelastrella astaxanthina Ki-4 and Scenedesmus obtusus Oki-4N; both strains were isolated under high light conditions. These AstaPs are classified as a novel family of carotenoprotein and are useful for providing valuable astaxanthin in water-soluble form; however, the distribution of AstaP orthologs in other microalgae remains unknown. Here, we examined the distribution of AstaP orthologs in the family Scenedesmaceae with two model microalgae, Chlamydomonas reinhardtii and Chlorella variabilis. The expression of AstaP orthologs under photooxidative stress conditions was detected in cell extracts of Scenedesmaceae strains, but not in model algal strains. Aqueous orange proteins produced by Scenedesmaceae strains were shown to bind astaxanthin. The protein from Scenedesmus costatus SAG 46.88 was purified. It was named ScosAstaP and found to bind astaxanthin. The deduced amino acid sequence from a gene encoding ScosAstaP showed 62% identity to Ki-4 AstaP. The expression of the genes encoding AstaP orthologs was shown to be inducible under photooxidative stress conditions; however, the production amounts of AstaP orthologs were estimated to be approximately 5 to 10 times lower than that of Ki-4 and Oki-4N.     

Priming effect of bamboo (Phyllostanchys edulis Carrière) biochar application in a soil amended with legume

Abstract

Biochar application to soils can mitigate carbon dioxide (CO₂) by increasing soil carbon (C) sink, but also causes increased CO₂ released from soils through priming effects of soil organic carbon (SOC). However, priming effects of biochar application on SOC are complex, showing inconsistent results, and further complicated when applied with other substrates such as organic amendment (OA). Incubation experiments were conducted using Typic Durudand with bamboo (Phyllostanchys edulis Carrière) biochar (400°C) and OA (crotalaria) applied individually, simultaneously or with biochar applied 5 weeks prior to OA application. After 56 d of incubation, cumulative CO₂ released from soils with no amendments (control), biochar only (BC), OA only (OA), simultaneous (BC+OA), and differently timed (BCP+OA) applications reached 313, 326, 1270, 1535 and 1311 mg CO₂ kg^?1, respectively. The OA application distinctly increased CO₂ released from the soils due to its decomposition. The OA decomposition rates were comparable with OA and BC+OA, while those with BCP+OA were lower than those with other treatments during early incubation. Net CO₂ (CO_{2-(treatment)} ? CO_2-control) from soils with BC, OA, BC+OA and BCP+OA yielded 13, 957, 1222 and 998 mg CO₂ kg^?1, respectively. Primed CO_2-BC of 13 mg CO₂ kg^?1 was equivalent to 4.2% of priming effect relative to CO_2-control. Primed CO_2-BC+OA [net CO_2-BC+OA ? (net CO_2-BC + net CO_2-OA)] and primed CO_2-BCP+OA were 252 and 28 mg CO₂ kg^?1, equivalent to 26% and 2.9% of priming effects relative to sum of net CO_2-BC + net CO_2-OA, respectively. The priming effect with BC was negligible likely because of limited amounts of biochar labile C to induce co-metabolism, while BC+OA showed a modest priming effect most likely as a result of co-metabolism induced by additional mineralization of presumably SOC and/or biochar, because the OA decomposition rates were not affected by biochar application. The priming effect with BCP+OA was comparable to that with BC likely due to changes in soil properties caused by biochar application prior to OA, likely from slowed decomposition rates of OA.     

Effects of astaxanthin‐enriched yeast on mucosal IgA induction in the jejunum and ileum of weanling mice

The present study was conducted to clarify the effects of astaxanthin‐enriched yeast on the concentration of immunoglobulin A (IgA), the numbers of IgA antibody‐secreting cells (ASC) and the messenger RNA (mRNA) expression of IgA C‐region in the jejunum and ileum of weanling mice. Weanling mice were fed rodent feed or astaxanthin‐enriched yeast‐supplemented rodent feed for 7, 14 or 21 days. Supplemental astaxanthin‐enriched yeast increased the numbers of IgA ASC in the jejunum and ileum after 7, 14 and 21 days of treatment. Supplemental astaxanthin‐enriched yeast increased IgA concentrations in the jejunum after 21 days of treatment, but IgA concentrations in the ileum were not affected by the treatment. The mRNA expressions of IgA C‐region in the jejunum after 14 and 21 days of treatment and the ileum after 14 days of treatment were enhanced by supplementation of astaxanthin‐enriched yeast. These results indicate that supplementation of astaxanthin‐enriched yeast is effective to enhance the numbers of IgA ASC in the jejunum and ileum and IgA concentrations in the ileum of weanling mice.     

Carotenoids in algae: distributions, biosyntheses and functions

For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or class-specific carotenoids, such as fucoxanthin, peridinin and siphonaxanthin. The distribution of α-carotene and its derivatives, such as lutein, loroxanthin and siphonaxanthin, are limited to divisions of Rhodophyta (macrophytic type), Cryptophyta, Euglenophyta, Chlorarachniophyta and Chlorophyta. In addition, carotenogenesis pathways are discussed based on the chemical structures of carotenoids and known characteristics of carotenogenesis enzymes in other organisms; genes and enzymes for carotenogenesis in algae are not yet known. Most carotenoids bind to membrane-bound pigment-protein complexes, such as reaction center, light-harvesting and cytochrome b(6)f complexes. Water-soluble peridinin-chlorophyll a-protein (PCP) and orange carotenoid protein (OCP) are also established. Some functions of carotenoids in photosynthesis are also briefly summarized.     

Effects of 25‐hydroxy‐cholecalciferol on the development of osteochondrosis in swine

The principal objective of this experiment was to evaluate the effect of 25‐hydroxy‐cholecalciferol (25‐OH‐D₃) on the development of osteochondrosis in 6‐ to 110‐kg castrated male pigs. The growth rate and serum calcium and inorganic phosphate levels neither increased nor decreased in response to supplementation of 25‐OH‐D₃. However, supplemental 25‐OH‐D₃ significantly increased serum levels of 25‐OH‐D₃ and 1α,25‐hydroxy‐cholecalciferol without any influence on bone mineral density. The 25‐OH‐D₃‐treated group had significant (P < 0.05) reduced incidence of osteochondrotic lesions compared to the control group as evidenced by macroscopically examining the articular cartilage of the distal humerus (32.4% vs. 59.3%) and distal femur (47.1% vs. 87.5%). Likewise, supplemental 25‐OH‐D₃ significantly reduced osteochondrotic lesions over the control when histologically examining humerus (20.6% vs. 43.8%) and femur (52.9% vs. 87.5%). The results of this experiment suggested that 25‐OH‐D₃ supplementation in pig diets had a tendency to promote normal endochondral ossification, inhibit osteochondrosis progression and possibly regenerate destroyed cartilage tissue.     

Sperm traits of masculinized fish relative to wild‐type males: a systematic review and meta‐analyses

Environmental sex reversal (ESR), whereby environmental effects (e.g. exogenous chemicals) override genetic sex determination, is a commonly used technique in aquaculture and physiology research. We performed a systematic review and meta‐analyses of the literature that compares the sperm characteristics of masculinized genotypic females to wild‐type males. We detected no mean differences between the ejaculate volume, sperm motility, duration or linearity of each type of male. We found some large mean differences in sperm concentration (d = 2.541, CI = ?0.004 to 5.086), reproductive success (d = ?1.400, CI = ?2.943 to 0.142), semen osmolality (d = 1.850, CI = 0.622 to 3.077) and sperm velocity (d = ?0.933, CI=?1.426 to ?0.441); in the case of the latter two traits, the mean effect was statistically significant. However, any significance did not stand up to a more conservative analysis. Additionally, heterogeneity was high and we found that where large differences between the sperm of sex‐reversed and wild‐type males are reported, these effects are attributable to sperm sampling methodology. Overall, we found little evidence for large systematic differences between the sperm produced by masculinized and wild‐type male fish. Thus, masculinized genotypic females may enjoy reproductive success comparable to genotypic males. This conclusion leads to two potential implications: (i) sex‐reversed fish may influence the dynamics of wild populations and (ii) aquaculture practices may use ESR to produce males with sperm quality similar to that of genotypic males. Most studies appear to have been performed in aquaculture species (i.e. Salmonidae); thus future experiments in non‐model organisms may provide important insights in to the uniformity of the effects described.