Absence of Sperm Factors as in the Parthenogenesis Does Not Interfere on Bovine Embryo Sensitiveness to Heat Shock at Pre‐Implantation Stage

Oocyte has been considered the major contributor for embryo thermo‐tolerance. However, it was shown that sperm factors can be transferred to the oocyte during fertilization, raising the question of whether the absence of such factors could interfere on embryo thermo‐tolerance. In this study, we used parthenogenesis to generate bovine embryos without spermatozoa in order to test whether the absence of sperm factors could influence their thermo‐sensitiveness at early stages. In vitro fertilized (IVF) and parthenogenetic (PA) embryos at 44 h post‐insemination/chemical activation were exposed to 38.5°C (control) or 41°C (heat shock) for 12 h and then developed for 48 h and up to blastocyst stage. Apoptosis index and expression of PRDX1, GLUT1, GLUT5 and IGF1r genes in blastocysts derived from heat‐shocked embryos were also evaluated. The heat shock decreased the blastocyst rate at day seven (p < 0.05) for IVF embryos and at day eight (p < 0.01) for both IVF and PA embryos. Total cell number was not affected by heat shock in IVF and PA blastocysts, but there was an increased proportion (p < 0.05) of apoptotic cells in heat‐shocked embryos when compared to controls. There was no interaction (p > 0.05) between method of activation (IVF and PA) and temperature (38.5°C or 41.5°C) for all developmental parameters evaluated. Expression of GLUT1 gene was downregulated (p < 0.05) by heat shock in both IVF and PA blastocyst whereas expression of GLUT5 and IGF1r genes was downregulated (p < 0.05) by heat shock in PA blastocysts. Those data show that the heat shock affects negatively the embryo development towards blastocysts stage, increases the apoptotic index and disturbed the expression of some genes in both IVF and PA embryos, indicating that the presence or absence of sperm factors does not influence the sensitivity of the bovine embryo to heat shock.     

Effects of Intrauterine Devices in Mares: A Histomorphological and Immunohistochemical Evaluation of the Endometrium

Oestrous suppression by intrauterine devices (IUDs) is caused by prolongation of luteal function, but the biological mechanism is unknown. The aim of the study was to investigate mechanisms which could explain the action of IUDs. Thirty mares were age‐matched and either inseminated (AI, n = 15) or fitted with an IUD (IUD, n = 15) and subsequently divided into four groups: AI‐P, pregnant (n = 8); AI‐N, non‐pregnant (n = 7); IUD‐P, prolonged luteal phase (n = 7); and IUD‐N, normal luteal phase (n = 8). The median ages were 5.5 and 7 years in AI‐P and IUD‐P groups and 14 and 11 years in AI‐N and IUD‐N groups, respectively. On Day 15 after ovulation, an endometrial biopsy was obtained to study histomorphological and immunohistochemical expression patterns of uterine proteins (uteroferrin, UF; uterocalin, UC; uteroglobin, UG), oestrogen and progesterone receptors (ER, PR), proliferation marker Ki‐67 and content of inflammatory cells. Expression of UF was higher in IUD mares; the difference between pregnant and IUD‐P mares was significant. Mares exhibiting a prolonged luteal phase (AI‐P, IUD‐P) showed only mild angiosclerosis and lower expression of both ER and PR than mares with a normal luteal phase (AI‐N, IUD‐N). No significant differences were detected in the numbers of inflammatory cells, with the exception of macrophages, which were more numerous in AI‐P than AI‐N mares. Although inflammatory cells were not detected in IUD mares, increased UF levels may indicate chronic inflammation. Young age and normality of the endometrial blood vessels may improve the efficacy of IUDs.     

Effects of Constant, 9 and 16-h Light Cycles on Sperm Quality, Semen Storage Ability and Motile Sperm Subpopulations Structure of Boar Semen

This study was performed to test the effect that two separate, daily, constant-light regimes of both 9 and 16 h could have on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure and the ability of its conservation at 16 degrees C. Results show that both luminous regimes have slight, specific effects on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure. Furthermore, the conservation ability at 16 degrees C of boar semen was not significantly different between both photoperiods. When a temporal study was performed, results showed that semen quality and motility parameter changes were stabilized at nearly constant values from the second month of the study to the last month in both luminous regimes, indicating a rapid light-related effect on testicular function. Our results indicate that light regimes oscillating from 9 h daily to 16 h daily are of little importance in the control of boar-semen quality in a farming environment.     

Amelioration of cadmium stress in gladiolus (Gladiolus grandiflora L.) by application of potassium and silicon

Gladiolus corms were grown in media contaminated with cadmium (Cd) (50 mg kg^?1) and supplemented with silicon (Si) and potassium (K). The role of Si and K for mitigation of Cd toxicity was evaluated. Cd-induced stress generated significantly increased level of oxidative stress markers including hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) in gladiolus. The application of K and Si improved the production of protein and proline in the treated plants. Moreover, K and Si supplemented plants exhibited an improvement in the activity of antioxidant enzymes and a reduction in the level of MDA, H₂O₂ and Cd uptake under Cd stress. Application of K and Si also enhanced the uptake of mineral nutrients including calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S) and K. The plants supplemented with K and Si exhibited a higher amount of total phenolics and flavonoids. The combined effect of Si and K was more pronounced regarding beneficial effects on gladiolus plants compared to individual effect of these elements under Cd stress. The current research reveals that Si and K may improve gladiolus growth by decreasing the oxidative stress and Cd uptake and by increasing the activity of antioxidant defense enzymes, the quantity of secondary metabolites and plant nutrition.     

The development and integrity of equine pre‐antral follicles cultured in vitro with follicle‐stimulating hormone (FSH) supplementation

This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200 ng/ml) in supplemented MEM+ on the development of equine pre‐antral follicles that were cultured in vitro for 2 or 6 days. The ovaries (n = 5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3 × 3 × 1 mm were obtained from each animal. The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM + (D2); MEM + (D6); MEM + 10 ng/ml of FSH (D2); MEM + 10 ng/ml of FSH (D6); MEM + 50 ng/ml of FSH (D2); MEM + 50 ng/ml of FSH (D6); MEM + 100 ng/ml of FSH (D2); MEM + 100 ng/ml of FSH (D6); MEM + 200 ng/ml of FSH (D2); and MEM + 200 ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre‐antral follicles, the groups with 100 ng/ml FSH of 2‐days culture as well as 50, 100 and 200 ng/ml FSH of 6‐days culture provided the best results. In conclusion, the in vitro culture of abattoir‐derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6 days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle.     

Gold nanoelectrodes of varied size: transition to molecule-like charging

A transition from metal-like double-layer capacitive charging to redox-like charging was observed in electrochemical ensemble Coulomb staircase experiments on solutions of gold nanoparticles of varied core size. The monodisperse gold nanoparticles are stabilized by short-chain alkanethiolate monolayers and have 8 to 38 kilodaltons core mass (1.1 to 1.9 nanometers in diameter). Larger cores display Coulomb staircase responses consistent with double-layer charging of metal-electrolyte interfaces, whereas smaller core nanoparticles exhibit redox chemical character, including a large central gap. The change in behavior is consistent with new near-infrared spectroscopic data showing an emerging gap between the highest occupied and lowest unoccupied orbitals of 0.4 to 0.9 electron volt.     

First glimpse into the origin and spread of the Asian longhorned tick,Haemaphysalis longicornis,in the United States

Established populations of Asian longhorned ticks (ALT), Haemaphysalis longicornis, were first identified in the United States (US) in 2017 by sequencing the mitochondrial cytochrome c oxidase subunit I (cox1) ‘barcoding’ locus followed by morphological confirmation. Subsequent investigations detected ALT infestations in 12, mostly eastern, US states. To gain information on the origin and spread of US ALT, we (1) sequenced cox1 from ALT populations across 9 US states and (2) obtained cox1 sequences from potential source populations [China, Japan and Republic of Korea (ROK) as well as Australia, New Zealand and the Kingdom of Tonga (KOT)] both by sequencing and by downloading publicly available sequences in NCBI GenBank. Additionally, we conducted epidemiological investigations of properties near its initial detection locale in Hunterdon County, NJ, as well as a broader risk analysis for importation of ectoparasites into the area. In eastern Asian populations (China/Japan/ROK), we detected 35 cox1 haplotypes that neatly clustered into two clades with known bisexual versus parthenogenetic phenotypes. In Australia/New Zealand/KOT, we detected 10 cox1 haplotypes all falling within the parthenogenetic cluster. In the United States, we detected three differentially distributed cox1 haplotypes from the parthenogenetic cluster, supporting phenotypic evidence that US ALT are parthenogenetic. While none of the source populations examined had all three US cox1 haplotypes, a phylogeographic network analysis supports a northeast Asian source for the US populations. Within the United States, epidemiological investigations indicate ALT can be moved long distances by human transport of animals, such as horses and dogs, with smaller scale movements on wildlife. These results have relevant implications for efforts aimed at minimizing the spread of ALT in the United States and preventing additional exotic tick introductions.     

Effect of Acute Bull Exposure Around the Time of Artificial Insemination on Serum Oxytocin and Progesterone Concentrations and Pregnancy Rates in Dairy Cows

This study examined the effect of acute bull exposure around the time of artificial insemination (AI) on oxytocin and progesterone concentrations, and pregnancy rates in dairy cows. Ninety six dairy cows, stratified according to parity into primiparous and pluriparous, were divided into three groups; short bull exposure (SBE; 10 min, n = 32), long bull exposure (LBE; 4 h, n = 32) or no bull exposure (NBE; n = 32). On day 45 post‐partum, all cows were treated with PGF2α on three occasions 11–14 days apart to synchronize oestrus. They were submitted to fixed time AI 80 h after the third PGF2α injection. Cows in the SBE and LBE groups were artificially inseminated 5 min after the introduction of the bull. From a subset of cows (n = 6 per group; three primiparous and three pluriparous), blood samples were collected once every 5 min starting 15 min before AI until 15 min after AI and analysed for oxytocin concentrations. Additional blood samples were collected for measurements of progesterone (P4) concentrations once daily for 4 days starting on the day of AI and once every 3 days thereafter until day 22. The effects of bull exposure, time, parity, difficulty of AI, and pregnancy on oxytocin and P4 concentrations were analysed using the mixed linear model procedure. Mean oxytocin concentrations or change in oxytocin concentrations after bull exposure or AI were not different among groups. Pregnancy rates for the NBE, SBE and LBE groups were 55.5%, 33.3% and 44.4%, respectively, and were not different among groups. In conclusion, acute bull exposure around the time of AI did not affect oxytocin and progesterone concentrations and did not improve pregnancy rates in dairy cattle under these farms conditions.