tRNA^(Glu)-derived fragments from embryonic extracellular vesicles modulate bovine embryo hatching

Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate embryo hatching.In this study,we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA(miRNA)cargo of preimplantation embryonic extracellular vesicles(EVs)influences embryo development.We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts.The majority of tsRNAs was identified as tRNA halves originating from the 5'ends of tRNAs.Among the 148 differentially expressed tsRNAs,the 19 nt tRNA fragment(tRF)tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts.RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group(P<0.05).Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching(P<0.05).Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation.In summary,tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions,and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching,while influencing embryo implantation-related genes and pathways.These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.

Effect of Six Bacterial Strains on the Activity of Second Instar Larvae and Egg Hatching of Meloidogyne incognita

[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita.

Effects of Dietary Straw Content on Growth and Development of Locusta migratoria and Its Egg Hatching

[Objectives]This study was conducted to investigate the effects of dietary straw content on the growth and development of oriental migratory locusts(Locusta migratoria),as well as the effects of temperature and substrate on their egg hatching.[Methods]The eggs of oriental migratory locusts were hatched at 15,20,25,30,35,and 40℃in sawdust,soil and sawdust+soil conditions,respectively,to determine suitable environmental conditions for artificial hatching of oriental migratory locusts.Rice straw was added at 0%,20%,40%,60%,80%and 100%to the basic diet,and the obtained diets was feed to oriental migratory locusts at the 4^(th)instar,to investigate the effects on their growth and development.[Results]The eggs of oriental migratory locusts had a good hatching rate at 25-30℃,and sawdust was the best choice for their hatching substrate.Adding 40%of rice straw to the diet could ensure the normal growth and development of oriental migratory locusts while consuming as much rice straw as possible.[Conclusions]This study explored a technical solution for efficiently producing insect protein from discarded crop straw(treating waste with insects,and turning waste into treasure),providing support for breeding of oriental migratory locusts and locust disaster prevention.

Effects of Varying Temperature and Constant Temperature on Hatching Result of Fertilized Peacock Eggs

In order to investigate the effect of temperature on hatching result of fertilized peacock eggs, they were hatched under conditions of varying temperature and constant temperature respectively. The result shows that the hatching rate in the varying temperature treatment group （Group Ⅰ） is higher than that in the constant temperature treatment group （Group Ⅱ）. It suggests that the varying temperature treatment （high temperature in the early period, medium temperature in the middle period, slightly lower temperature in the late period, and slightly higher temperature in the hulling period） is in line with the optimum temperature variation in the hatching of fertilized peacock eggs, contributing the hatching of fertilized peacock eggs.

Heavy metal exposure reduces hatching success of Acartia pacifica resting eggs in the sediment

The potential effects of three heavy metals （Cu, Pb, and Cd） on hatching success ofAcartia pacifica resting eggs in the sediment of Xiamen Bay were experimentally investigated. The number ofA. pacifica nauplii hatched from the sediment sharply decreased with the increase of metal concentration and exposure time from 3 to 30 d. An increase of the Cu concentration from 34.8 to 348 mg/kg, reduced the number of hatched nauplii by 46.6%-100%. An increase of the Pb concentration from 75.2 to 752 mg/kg, reduced the number of hatched nauplii by 21.4%-78.9%. An increase of the Cd concentration from 0.68 to 6.8 mg/kg, reduced the number of hatched nauplii by 31.6%-94.7%. The number of nauplii also significantly decreased with the increase of mixed-metal concentration and exposure time in the mixed-metal test. Trimmed Spearman-Karber analysis gave sediment metal 72-h LC50 values of 1.25 mmol Cu/kg, 1.73 mmol Pb/kg, and 0.054 mmol Cd/kg, which suggested that Cd was the most toxic to A. pacifica resting eggs in the three tested metals. The results indicate that heavy metals with higher concentrations can reduce recruitment of A. pacifica nauplii from benthic resting eggs to planktonic population.

Monochromatic green light stimulation during incubation shortened the hatching time via pineal function in White Leghorn eggs

Background:Effect of monochromatic green light illumination on embryo development has been reported in chickens.The avian pineal gland is an important photo-endocrine organ formed by a mediodorsal protrusion during embryonic development.However,the involvement of pineal gland in the light transduction process remains to be elucidated.In the present study,we investigated the influence of monochromatic green light on hatching time and explored the possible mechanism via pineal function.Results:A total of 600 eggs of White Leghorn(Shaver strain)were incubated under photoperiods of either 12 h of light and 12 h of darkness using monochromatic green light(12L:12D group)or 24 h of darkness(0L:24D group)for 18 d.Compared to 0L:24D group,the green light stimulation shortened the hatching time without extending the hatch window or impairing hatchability.The liver of embryos incubated in the 12L:12D light condition was heavier than those of the 0L:24D group on d 21 post incubation which may be linked to the observed increase in the serum concentration of insulin-like growth factor 1(IGF-1);primary secretion of the liver.Histological structure analysis of pineal gland demonstrated that the light stimulation increased follicle area,wall thickness and lumen area on d 10 and d 12 post incubation.Rhythmic function analysis demonstrated that three clock related genes(brain and muscle ARNT-like-1,BMAL1;circadian locomotor output cycles kaput,CLOCK;and cryptochrome-1,CRY1)and a melatonin rate-limiting enzyme related gene(arylalkylamine N-acetyltransferase,AANAT)were rhythmically expressed in the pineal gland of the 12L:12D group,but not in the 0L:24D group.Simultaneously,the light stimulation also increased the concentration of melatonin(MT),which was linked to hepatocyte proliferation and IGF-1 secretion in previous studies.Conclusions:The 12L:12D monochromatic green light stimulation during incubation shortened hatching time without impairing hatching performance.Pineal gland’s early histological development and maturation of its rhythmic function were accelerated by the light stimulation.It may be the key organ in the photo-endocrine axis that regulates embryo development,and the potential mechanism could be through enhanced secretion of MT in the 12L:12D group which promotes the secretion of IGF-1.

Effect of laser assisted hatching on outcome of assisted reproductive technology

Objective: To determine whether laser-assisted hatching can improve clinical outcome of assisted reproductive techniques in both unselected patients and patients with advanced female age, with recurrent implantation failure, or who are using frozen-thawed embryos. Study design: Prospective randomized study. Patients and methods: 179 consecutive women scheduled for intracytoplasmic sperm injection (ICSI) were randomised to either laser assisted hatching (LAH) or non LAH group. Patients were divided into 94 test and 85 control groups. On the day of embryo transfer, the zona pellucida of the selected embryos in the test group was thinned by using an infrared optical laser system, whereas in the control group they were left intact. Clinical pregnancy rates (CPR) and implantation rates (IR) were estimated. Result(s): Patients that underwent LAH (n = 94) had CPR, and IR of 35.1% and 50%, respectively. Patients that did not undergo LAH (n = 85) had lower CPR (28.2%, P = 0.324) and IR (33%, P = 230), with no statistically significant difference P Conclusion: The current study suggested that there is no need for the routine use of laser assisted hatching. However, there is evidence of laser assisted hatching benefit in selected

Assisted Hatching in Couples with Advanced Maternal Age： A Systematic Review and Meta-analysis

This systematic review aimed to evaluate the efficacy and safety of assisted hatching （AH） performed in couples with advanced maternal age. We searched for randomized controlled trials （RCTs） in electronic databases, including MEDLINE, EMBASE and CENTRAL （from inception to January 2018）; in addition, we hand-searched the reference lists of included studies and similar reviews. We included RCTs comparing AH versus no treatment （control）. The meta-analysis was performed by RevMan 5.3 software. The search retrieved 943 records and 8 RCTs were included, comprising 870 cycles （n=440 for AH, and n=430 for control）. There was no significant difference in the rates of live birth （RR 0.88, 95% CI 0.65 to 1.18, 3 RCTs, n-427,I^2=0%）, clinical pregnancy （RR 1.00, 95% CI 0.83 to 1.19, 8 RCTs, n=870, I^2=22%）, implantation （RR 1.07, 95% CI 0.83 to 1.39, 4 RCTs, n=1359, I^2=0%）, miscarriage （RR 1.13, 95% CI 0.66 to 1.94, 2 RCTs, n=116, I^2=0%） and multiple pregnancy （RR 0.89, 95% CI 0.31 to 2.52, 1 RCT, n=97,I^2=not applicable） between the treatment group and control group. No reasonable conclusions could be drawn regarding reproductive outcomes after AH in patients with advanced maternal age due to the small sample pooled in meta-analyses. Studies of high methodological quality and with adequate power are necessary to further investigate the value of AH in assisted conception of those patients.

The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica

The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monocuhure and mixture of the two species were examined on the egg-hatching success ofArgopecten irradiarts Lamarck, and the population growth of Brachionus plicatilis MUller and Moina mongolica Daday. The results showed that monocuhure of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities （ED50） inhibiting the egg hatching success of A. irradhms for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm^3 , respectively. Monoculture of P. dongha/ense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis （ 1 × 10^4 ～ 3 ×10^4 cells/cm^3 ） and M. mongolica （2 × 10^4～5 ×10^4 cells/cm^3 ） ; P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis （4 × 10^4 ～ 10×10^4 cells/cm^3 ） and M. mongolica （ 10 ×10^4 cells/cm^3）. When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.

Induced nest spawning and artificial hatching of the fertilized eggs of mudskipper, Boleophthalmus pectinirostris

In this study, nest spawning was successfully induced by exogenous hormone injections and seawater flow stimulation, and optimum condition for hatching fertilized eggs of burrow fish mudskipper, Boleophthalmus pectinirostris, was searched. Apart from spawning inside the nests, females also spawned outside the nests. The percentages of spawned nests were 8.0% to 24.2%. Most eggs were observed adhered to the inner wall of the top half of the nest. Fertilization rates of the nest-spawned eggs varied from 17.3% to 80.8%. Females could spawn after being artificially confined inside the nests with males at ratios of 1:1 or 1:2, but the spawned eggs were not fertilized. Mean hatching rates of artificially fertilized eggs incubated in round plastic buckets were 32.7%-70.6%, and in the net cages, were 4.2%-20.5%, respectively. Mean hatching rates of nest- fertilized eggs incubated in the round plastic buckets were 33.6%-76.3%, and in the net cages, were 5.9%-25.2%. Results showed that round bucket incubation was the best way for hatching fertilized eggs of mudskipper. Keeping the hatching seawater flowing is an important way for increasing the hatching rates of the mudskipper fertilized eggs.

Effects of Lanthanum on Egg Hatching and Nauplius Metamorphosis of Penaeus Chinensis

Effects of lanthanum on egg hatching and nauplius metamorphosis of Penaeus chinensis(P. chinensis) were studied. The experimental results showed that the optimum concentration of lanthanum was 0 30～1 80 mg/L for monocell and dicell stage of embryo development, the egg hatching rates were raised by 33 5%～49 1%; and it was 0 90～1 80 mg/L for poly cell stage, the egg hatching rate was raised by 17 1%～23 5%. The optimum concentration was 0 90～1 50 mg/L for nauplius metamorphosis, the metamorphosis rate from nauplius(N 1) to protozoea(Z 1) was raised by 9 4%～11 7%. The promotion of lanthanum to egg embryo development was completed through absorption of lanthanum by egg in the water. The absorption capacity of one egg for lanthanum was 5 89 μg.

Study on Hatching Rate of Artemia fanciscana Cysts in Different Sources of Saline

A comparison of Arternia cysts hatching （Artemia franciscana） were conducted on bleaching and non-bleaching with sodium hypochloride on five dilution of salt solution by using sea water, sea salt solution, artificial sea salt solutions, iodine added cooking salt solution, and rock salt solutions. All solutions were adjusted at 30 ppt of salinity in 1 litter cylinder. The experiment was carried out with Factorial Experiment in CRD. After 24 hours, a randomized count of living Artemia was taken a photograph of Artemia size by stereo microscope. A statistic analysis showed that all data of bleaching and non-bleaching were no significant difference （P 〉 0.05）. The hatching ability of Artemia cysts in solutions was examined and the results showed that sea salt solution was 327.33 × 103.4. 28,536.5263 Nauplii/liter, sea water 316 ×10^3± 20,420.5779 Nauplii/liter, artificial sea salt solutions 314.33× 10^3 ± 34,268.5473 Nauplii/liter, iodine added cooking salt solution 309.66 ± 10^3 .4- 22,898.3260 Nauplii/liter, and rock salt solutions 305.33 ± 10^3 ± 25,579.9401 Nauplii/liter, respectively. The body length of Artemia was compared and the data showed that there was no significant difference （P 〉 0.05）. The highest body length was found in sea salt solution 527.32 ± 4.70μm, sea water 521.65±8.51 μm, artificial sea salt solutions 522.08 ± 10.04 μm, iodine added cooking salt solution 522.67 ±7.87 μm, and rock salt solutions 516.33 ±11.15μm, respectively.

In Vitro Fertilization Outcomes Following Assisted Hatching of Embryos with Thick Zona Pellucida—A Prospective Randomized Study

Purpose: Impaired hatching is associated with implantation failure following in vitro fertilization (IVF). Thickening or hardening of the zona pellucida (ZP) has been proposed as a factor in this impairment. We examined whether selective assisted hatching (AH) is beneficial with embryos having a thick ZP. Methods: This prospective, randomized controlled study was performed in the IVF unit of an obstetrics and gynecology department in a university-affiliated hospital. Only patients undergoing IVF and having a ZP thickness of ≥17 μm measured in all their embryos were included. In the intervention group, AH was applied to all embryos, before their transfer. In the control group, embryos were transferred without AH. Implantation, clinical pregnancy and live birth rates were the study endpoints. Results: Both study arms were comparable in most baseline parameters. The two groups did not differ in implantation rates (14.1% control vs. 8.92% intervention, odds ratio (OR) = 0.5974, 95% confidence interval (CI) 0.325 - 1.1), clinical pregnancy rates (36.7% vs. 25.8%, OR = 0.6025, 95% CI 0.274 - 1.325), or live birth rates (25% vs. 18.9%, OR = 0.7021, 95% CI 0.291 - 1.691). Conclusions: Selecting embryos for AH by their ZP thickness as a sole parameter was not found to be beneficial and to improve IVF outcome.

A Study on Artificial Hatching of Chinese Bombyx mandarina Moore

Diapause eggs of Bombyx mandarina Moore from Wujiang, Jiangsu Province, China, were used to study the artificial hatching of B. mandarina Moore. The results showed that the highest hatchability was obtained by instant treatment with hydrochloric acid （HC1, specific gravity 1.065-1.075） for 5 rain under 46℃. After the B. mandarina eggs were cold stored at 5℃ for 40 days, the highest hatchability was obtained by treatment with HC1 （specific gravity 1.092） for 6 minutes under 47.8℃. For the B. mandarina eggs that were stored at 25℃ for 28 d and then cold-stored at 5℃ for 0-100 days, the highest hatchability was obtained by treatment with HCI （specific gravity 1.092） for 6 rain at 47.8℃. The longer the cold storage period, the higher was the hatchability. Acid treatment on diapause eggs of B. mandarina for 6 rains at 47.8℃ with hydrochloric acid （specific gravity 1.092） before hatching in spring could obviously shorten the hatching stage and increase the hatchability.

Sea water environment copper requirement of egg hatching and naupliar metamorphosis of Peaneus chinensis

A new method was used to remove heavy metals in sea water. The requirement of copper in sea water ofegg hatching and naupliar metamorphosis of Penaeus chinensis was investored. A certain amount of copper ion andchelator nitrilotriacetic acid (NTA) were added in the de-heavy-metal-ionized sea water and then the cupric ion actvitywas calculated. The effects of copper ion on egg hatching and naupliar metamorphosis were observed. It was firstfound by experiments that trace ionic copper (10-10.80-10-8.80 mol/dm3) was essential to the growth and development of egg and nauplii of penaeid shrimp and chelated copper had no actions for these living processes,but in highconcentrations (>10 -7.80 mol/dm3) ionic copper was toxic. The nauplii were more sensitive to necessity and tokicityof ionic copper than eggs.

Effects of Lanthanum-Amino Acid Complexes on Egg Hatching and Nauplius Metamorphosis of Penaeus chinensis

Studies have been carried out on the effect of lanthanum-amino acid complexes on embryo development and nauplius growth ofPenaeus chinensis. The experimental results indicate that: (1)The optimum concentrations of lanthanum-proline and Lanthanumphenylalanine for the development of eggs in monocell and dicell stages are 1.50～ 4.00mg/L and 0.50～3.00 mg/L, respectively, the egg hatching rates being raised by 21.0 ～ 46.0% and 23.0 ～42.8% ( P ＜ 0.05 ) respectively. (2)The optimum concentrations of lanthanum- proline complex and Lanthanum-phenylalanine complex for the growth ofnauplii are 1.50～4.00 mg/L and 0.50～3.00 mg/L, the metamorphosis rate from nauplius to protozoea being raised by 16.4 ～27.5% and 20.4～26.7% (P ＜ 0.05 ) respectively. (3)The positive effect of lanthanum-amino acid complexes on egg hatching and nauplius metamorphosis of Penaeus chinensis is better than that of lanthanum. With regard to the positive effect, lanthanum-proline complex is better than Lanthanum-phenylalanine complex.

Effect of an Improved Mechanical Method for Assisted Hatching on the in vitro Development of Mouse Embryos

Objective To evaluate the safety and efficiency of an improved shape of opening for mechanical assisted hatching （AH） on the in virto development of mouse embryos. Methods A total of 622 KM BAI mouse embryos in 2-cell-4-cell stage were randomly divided into group A, group B and control group. A new mechanical AH method by improving the shape of opening in the ZP was used in group A, and a ＂-/ ＂-shaped opening was created. A ＂＋ ＂ -shaped opening was made in group B, while no opening was made in control group. Comparisons have been made among the three groups with regard to the duration of AH, the blastocyst formation and complete hatching rate, etc. Results The duration of AH in group A （43.25 ±3.46 s） was significantly shorter than that in group B （52.81 ±4.32 s, P 〈0.05）. The blastocyst formation rate on d 5 was not significantly different among the three groups （92.27%, 93.66% and 94.92% respectively, P 〉0.05）. The complete hatching rate of blastocysts on d 6 between group A and group B was no statistical difference （94.09% vs 92.71%, P 〉0.05）, but significantly higher than that in control group （43.32%, P 〈0.001）. No significant difference in the percentage of grade 1 blastocysts was found among the three groups on d 5 （85.22%, 82.81% and 86.63% respectively, P 〉0.05）. Conclusion R could enhance the process of embryo hatching and facilitate the hatching rate of blastocysts by using the improved mechanical AH method, which is of safety and efficiency to mouse embryo in the in vitro development.

Ecological Hatching Method for Misgurnus anguillicaudatus Fingerlings

[Objective]To improve the artificial propagation technique of Misgurnus anguillicaudatus,and to provide technical support for the industrialization development of M.anguillicaudatus in future.[Methods] The hatching rates,survival rates,deformity rates and parent morality rates of M.anguillicaudatus were compared by ecological hatching method and traditional hatching method.[Results]The hatching rate by ecological hatching method was 32.60% higher than that by traditional hatching method,showing extremely significant differences.The survival rate of M.anguillicaudatus fingerlings by ecological hatching method was2.32% higher than that by traditional hatching method.And the deformity rates of M.anguillicaudatus fingerlings by traditional hatching method and ecological hatching method were 26.50% and 24.14%,respectively,indicating no significant differences.The morality rates of female parents of M.anguillicaudatus were89.72% and 5.91% by traditional hatching method and ecological hatching method,respectively.[Conclusions]Ecological hatching method effectively improved the hatching rate and fingerling survival rate of M.anguillicaudatus,and reduced the morality rate of female parents,which was helpful to save the production cost,met the requirements for large-scale production of M.anguillicaudatus,and had good application prospect.

Hatching Hope

Sindayigaya Evariste, owner of Safe Chicken Farm in the suburb of Bujumbura, capital of Burundi, felt nervous each time his hens hatched chicks. Though he and his workers tried to provide the best environment for the hens, only a small portion of chicks would hatch. In Burundi, there are many other poultry. farmers like Evariste who are suffering without artificial hatching technologies and have to rely on hens to hatch chicks.

基于Hatch滤波的改进矩阵变换法在BDS多频模糊度解算中的应用

长基线条件下,空间相关性弱,电离层延迟残差和噪声影响变大,致使矩阵变换法模糊度解算过程中,窄巷组合受噪声影响大,单历元模糊度解算成功率低。因此,削弱电离层残差及噪声影响可以一定程度提高模糊度解算成功率。本文在分析矩阵变换算法基础上,利用Hatch滤波有效抑制伪距测量噪声和多径效应特点,结合弱电离层、低噪声的载波组合,通过相位平滑伪距代替组合伪距值参与解算,从而削弱电离层残差及观测噪声影响。通过实测数据分析,本文算法可有效提高矩阵变换法模糊度解算成功率。