Endogenous biosynthesis of docosahexaenoic acid(DHA)regulates fish oocyte maturation by promoting pregnenolone production

Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related to this phenomenon remains largely unknown.In this study,we employed two zebrafish genetic models,i.e.,elovl2^(-/-)mutant as an endogenous DHAdeficient model and fat1(omega-3 desaturase encoding gene)transgenic zebrafish as an endogenous DHA-rich model,to investigate the effects of DHA on oocyte maturation and quality.Results show that the elovl2^(-/-)mutants had much lower fecundity and poorer oocyte quality than the wild-type controls,while the fat1 zebrafish had higher fecundity and better oocyte quality than wildtype controls.DHA deficiency in elovl2^(-/-)embryos led to defects in egg activation,poor microtubule stability,and reduced pregnenolone levels.Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1,which encodes the cholesterol side-chain cleavage enzyme,thereby stabilizing microtubule assembly during oogenesis.In turn,the hypothalamic-pituitary-gonadal axis was enhanced by DHA.In conclusion,using two unique genetic models,our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.

Impact of stage-specific limb function exercises guided by a selfmanagement education model on arteriovenous fistula maturation status

BACKGROUND The exercise of limb function is the most economical and safe method to promote the maturation of arteriovenous fistula(AVF).However,due to the lack of a uni-fied exercise standard in China,many patients have insufficient awareness of the importance of AVF,leading to poor effectiveness of limb function exercise.The self-management education model can effectively promote patients to take pro-active health-related actions.This study focuses on the characteristics of patients during the peri-AVF period and conducts a phased limb function exercise under the guidance of the self-management education model to observe changes in fac-tors such as the maturity of AVF.AIM To assess the impact of stage-specific limb function exercises,directed by a self-management education model,on the maturation status of AVFs.METHODS This study is a randomized controlled trial involving 74 patients with forearm AVFs from the Nephrology Department of a tertiary hospital in Sichuan Province,China.Patients were randomly divided into an observation group and a control group using a random number table method.The observation group underwent tailored stage-specific limb func-tion exercises,informed by a self-management education model which took into account the unique features of AVF at various stages,in conjunction with routine care.Conversely,the control group was given standard limb function exercises along with routine care.The assessment involves the maturity of AVFs post-intervention,post-operative complications,and the self-management level of the fistula in both groups patients.Analyses were conducted using SPSS version 23.0.Count data were represented by frequency and percentage and subjected to chi-square test comparisons.Measurement data adhering to a normal distribution were presented as mean±SD.The independent samples t-test was utilized for inter-group comparisons,while the paired t-test was used for intra-group comparisons.For measurement data not fitting a normal distribution,the median and interquartile range were presented and analyzed using the Wilcoxon rank sum test.RESULTS At the 8-wk postoperative mark,the observation group demonstrated significantly higher scores in AVF symptom recognition,symptom prevention,and self-management compared to the control group(P<0.05).However,the variance in symptom management scores between the observation and control groups lacked statistical signi-ficance(P>0.05).At 4 wk after the operation,the observation group displayed a superior vessel diameter and depth from the skin of the drainage vessels in comparison to the control group(P<0.05).While the observation group did manifest elevated blood flow rates in the drainage vessels relative to the control group,this distinction was not statistically significant(P>0.05).By the 8-wk postoperative interval,the observation group outperformed the control group with notable enhancements in blood flow rates,vessel diameter,and depth from the skin of drainage vessels(P<0.01).Seven days following the procedure,the observation group manifested significantly diminished limb swelling and an overall reduced complication rate in contrast to the control group(P<0.05).The evaluation of infection,thrombosis,embolism,arterial aneurysm stenosis,and incision bleeding showed no notable differences between the two groups(P>0.05).By the 4-wk postoperative juncture,complications between the observation and control groups were statistically indistinguishable(P>0.05).CONCLUSION Stage-specific limb function exercises,under the guidance of a self-management education model,amplify the capacity of AVF patients to discern and prevent symptoms.Additionally,they expedite AVF maturation and miti-gate postoperative limb edema,underscoring their efficacy as a valuable method for the care and upkeep of AVF in hemodialysis patients.

Effect of thermal maturation and organic matter content on oil shale fracturing

The Pabdeh Formation represents organic matter enrichment in some oil fields,which can be considered a source rock.This study is based on the Rock–Eval,Iatroscan,and electron microscopy imaging results before and after heating the samples.We discovered this immature shale that undergoes burial and diagenesis,in which organic matter is converted into hydro-carbons.Primary migration is the process that transports hydrocarbons in the source rock.We investigated this phenomenon by developing a model that simulates hydrocarbon generation and fluid pressure during kerogen-to-hydrocarbon conversion.Microfractures initially formed at the tip/edge of kerogen and were filled with hydrocarbons,but as catagenesis progressed,the pressure caused by the volume increase of kerogen decreased due to hydrocarbon release.The transformation of solid kerogen into low-density bitumen/oil increased the pressure,leading to the development of damage zones in the source rock.The Pabdeh Formation’s small porethroats hindered effective expulsion,causing an increase in pore fluid pressure inside the initial microfractures.The stress accumulated due to hydrocarbon production,reaching the rock’s fracture strength,further contributed to damage zone development.During the expansion process,microfractures preferentially grew in low-strength pathways such as lithology changes,laminae boundaries,and pre-existing microfractures.When the porous pressure created by each kerogen overlapped,individual microfractures interconnected,forming a network of microfractures within the source rock.This research sheds light on the complex interplay between temperature,hydrocarbon generation,and the development of expulsion fractures in the Pabdeh Formation,providing valuable insights for understanding and optimizing hydrocarbon extraction in similar geological settings.

Enhancer of Shoot Regeneration 2(ESR2)regulates pollen maturation and vitality in watermelon(Citrullus lanatus)

Watermelon(Citrullus lanatus)holds global significance as a fruit with high economic and nutritional value.Exploring the regulatory network of watermelon male reproductive development is crucial for developing male sterile materials and facilitating cross-breeding.Despite its importance,there is a lack of research on the regulation mechanism of male reproductive development in watermelon.In this study,we identified that ClESR2,a VIIIb subclass member in the APETALA2/Ethylene Responsive Factor(AP2/ERF)superfamily,was a key factor in pollen development.RNA insitu hybridization confirmed significantClESR2 expression in the tapetum and pollen during the later stage of anther development.The pollens of transgenic plants showed major defects in morphology and vitality at the late development stage.The RNA-seq and protein interaction assay confirmed that ClESR2 regulates pollen morphology and fertility by interacting with key genes involved in pollen development at both transcriptional and protein levels.These suggest that Enhancer of Shoot Regeneration 2(ESR2)plays an important role in pollen maturation and vitality.This study helps understand the male reproductive development of watermelon,providing a theoretical foundation for developing male sterile materials.

CRISPR/Cas9-mediated knockout of E4 gene promotes maturation in soybean

Soybean is a broadly popular and extensively cultivated crop,however,many high-yield and high-quality varieties require specific growth conditions,restricting their widespread adoption.The appropriate light conditions and photoperiod must be attained for these varieties to thrive in new environments.In this study,we employed CRISPR/Cas9 to design two sgRNAs aimed at knocking out the maturity-related gene E4 in a major American soybean variety called''Jack'',which belongs to maturity group MGII.E4 gene is primarily involved in the photoperiodic flowering and maturity in soybean,making it an ideal candidate for genetic manipulation.We successfully obtained 1 homozygous E4-SG1 mutant type with 1-bp insertion,and 4 homozygous E4-SG2 mutants type with 2-bp deletion,7-bp deletion,61-bp deletion,and 1-bp insertion,respectively.The homozygous e4 mutant plants contained early termination codons devoid of transgenic elements.Additionally,no potential offtarget sites of the E4 gene were detected.A comparative analysis revealed that,unlike the wild-type,the maturity time of homozygous e4 mutants was early under both short-day and long-day conditions.These mutants offer novel germplasm resources that may be used to modify the photoperiod sensitivity and maturity of soybean,enhancing its adaptability to high-latitude regions.

Protective effect of resveratrol against cadmium-induced toxicity on ovine oocyte in vitro maturation and fertilization

Background:Heavy metal cadmium(Cd)is a widespread environmental contaminant with a potential toxicity that might negatively affect female reproduction and fertility.It has been reported that Cd exposure impaired the quality of oocytes and led to a defective maturation and fertilization,through oxidative stress induction.Resveratrol(Res)is a natural polyphenol with strong antioxidant properties that exhibited protective role in preventing oocyte redox homeostasis disruption and quality decline.Here,we explored whether the addition of Res to in vitro maturation(IVM)medium might act as a protection against Cd-induced toxicity on ovine oocyte maturation and fertilization.Firstly,we evaluated the effect of supplementing IVM medium with two different Res concentrations(1and 2μmol/L)on nuclear maturation and fertilization of oocytes matured under CdCl2(2μmol/L)exposure.Therefore,the concentration of 1μmol/L Res was selected to analyse the effects of this compound on intracellular ROS levels,mitochondrial(mt)distribution and activity,chromatin configuration,cytoskeleton morphology,cortical granules(CGs)distribution and mRNA expression of genes associated with cellular response to oxidative stress(i.e.SIRT1,SOD 1,GPX1,GSR,CAT)in Cd-exposed in vitro matured oocytes.Results:We found that 1μmol/L Res restored the reduced oocyte meiotic competence induced by Cd exposure as well as,Res sustained oocyte ability to be normally fertilized and decreased polyspermic fertilization at both tested concentrations.Moreover,we demonstrated that 1μmol/L Res mitigated Cd-induced alterations of oocyte cytoplasmic maturation by reducing reactive oxygen species(ROS)accumulation,preventing mt dysfunction,maintaining the correct meiotic spindle and cortical F-actin assembly and the normal cortical granule distribution as well as up-regulating SIRT1,SOD1 and GPX1 genes.Conclusions:Taken together,our findings highlighted the beneficial influence exerted by Res in preventing Cdinduced disturbance of nuclear and cytoplasmic maturation and subsequent fertilization in ovine oocytes.Res treatment may help to establish defence strategies counteracting Cd-induced toxicity on the female gamete.

A Review of Main Factors Involved in the Maturation of Oil Palm (Elaeis guineensis Jacq.) Fruit Bunches

The oil palm (Elaeis guineensis Jacq.) is a diploid perennial plant of the Arecaceae family. It is the most important plant cultivated for oil production. To ensure this production, certain optimal conditions are required: temperature, sunshine, rainfall, etc. The oil palm ensures its survival through the fruits borne on bunches located at the axis of the 17th to 20th leaves from the central stem. From pollination to the maturity of a bunch it takes about 4.5 to 6 months. Several events occur during this period: seed enlargement, weight increase, colour change, etc., but also important physiological changes: synthesis of some pigments (anthocyanin), increase in oil content correlated with the decrease in water content, etc. All of these constitute factors that can provide a better understanding of the biology of the seed. The aim of this work was to review some of the important parameters involved in the development and maturation of oil palm fruit bunches. These factors are classified into physiological, biochemical as well as environmental. The physiological parameters are color, appearance of embryo, seed weight and fruit detachment from bunches;Biochemical parameters include water content, oil content, carbohydrate, protein, mineral contents and lipase activity while temperature is the main environmental factor that affects fruit maturation. Thorough research has not yet been done at the different stages of maturation and ripening, thus a deep look into this may open up new avenues for research on early germinated oil palm seed production prior to seed dormancy.

A Computational Analysis of the Influence of Anastomosis Angle on Stenosis-Prone Locations during Radio-Cephalic Arteriovenous Fistula Maturation

In dialysis treatment, the radio-cephalic arteriovenous fistula (RCAVF) is a commonly used fistula, yet its low maturation rate remains a challenge. To enhance surgical outcomes, the relationship between stenosis-prone locations and RCAVF anastomosis angle is studied during maturation by developing two sets of RCAVF models for early (non-mature) and mature RCAVFs at five anastomosis angles. The impact of hemodynamics and wall shear stress (WSS) is examined to determine optimal anastomotic angles. Results indicate that acute angles produce more physiological WSS distributions and fewer disturbed regions, with early stenosis-prone regions located near the anastomosis that shift to the bending venous segment during remodeling. A pilot study comparing clinical and numerical results is conducted for validation.

Improvement of in vitro Cytoplasmic Maturation of Denuded Porcine Oocytes by Coculture with Follicular Mural Granulosa Cells

[Objective] This study aimed to improve the in vitro maturation quality of denuded porcine oocytes and provide scientific basis for establishing a stable and efficient denuded oocyte culture system. [Method] The first polar body extrusion rate, oocyte glutathione （GSH） content, positive rate of brilliant cresyl blue （BCB） staining and development potential of activated oocytes or fertilized oocytes were employed as main indicators to investigate the effects of follicular mural granulosa cell （MGC） coculture on cytoplasmic maturation of cumulus cell-removal oocytes （Denuded Oocyte, DO）. [Result] According to in vitro maturation results, compared with DO group, the first polar body extrusion rate of porcine oocytes in DO＋MGC group was not significantly different, but the nuclear maturation process was improved and was more similar to that in COC （cumulus-oocyte complex） group. Detection of GSH content in mature oocytes showed that there was no significant difference between DO＋ MGC group （optical density of 1 053.67） and COC group （optical density of 1 426.00） or between DO＋MGC group and COC＋GC group （optical density of 1 541.00）, however, GSH content in mature oocytes of DO group （optical density of 724.67） was significantly lower than that of COC group and COC＋GC group （P0.05）. Detection of glucose-6-phosphate dehydrogenase （G6PDH） activity showed that there was no significant difference in BCB positive oocyte rate between DO ＋MGC group （88.26% ） and COC group （92.75%） or between DO＋MGC group and DO group （82.86% ）, however, BCB positive oocyte rate of DO group was significantly lower than that of COC group （P0.05）. Furthermore, the cleavage rate and blastocyst rate of activated mature oocytes derived from DO ＋MGC group （94.98% and 43.67% , respectively） were significantly higher than those from DO group （52.54% and 8.97%, respectively） （P0.05）, and were not significantly different compared with those from COC group （97.11% and 38.30%, respectively）. In addition, the cleavage rate of fertilized oocytes derived from DO＋MGC group （72.65%） showed no significant difference compared with that from DO group （63.59%）, but the blastocyst rate of DO＋MGC group was significantly higher than that of DO group （9.88%） （P0.05）. [Conclusion] MGC coculture can significantly improve the in vitro cytoplasmic maturation quality of denuded porcine oocytes, thereby enhancing the subsequent developmental potential.

Effects of in Vitro Maturation Time of Oocytes on Sheep Nuclear Transfer Efficiency

[Objective] The study aimed to provide references for the time of oocyte maturation in vitro and enucleation in the course of sheep nuclear transfer(NT).[Method] Compared the effects of different maturation time of oocytes on enucleation efficiency and reconstructed embryo development by means of blind enucleation and fluorescence microscopy.[Result] Treatment of IVM(in vitro maturation)19-21 h was significantly higher than IVM 16-18 h treatment in oocyte maturation rate(P<0.05)and was significantly higher than IVM 22-24 h treatment in enucleation rate(P<0.05).Three treatments had no significant difference in cleavage rate and blastocyst rate(P>0.05),but IVM 19-21 h treatment was significantly higher than the other 2 treatments in average cell number of blastocysts(P<0.05).[Conclusion] The appropriate in vitro maturation time of oocytes was 19-21 h for sheep nuclear transfer,which could significantly improve the quality of blastocysts according to the cell number per blastocyst(P<0.05).

CX3 chemokine receptor 1 deficiency leads to reduced dendritic complexity and delayed maturation of newborn neurons in the adult mouse hippocampus

Previous studies have shown that microglia impact the proliferation and differentiation of neu- rons during hippocampal neurogenesis via the fractalkine/CX3 chemokine receptor i （CX3CRI） signaling pathway. However, whether microglia can influence the maturation and dendritic growth of newborn neurons during hippocampal neurogenesis remains unclear. In the present study, we found that the number of doublecortin-positive cells in the hippocampus was decreased, and the dendritic length and number of intersections in newborn neurons in the hippocampus were reduced in transgenic adult mice with CX3CR1 deficiency （CX3CRl^GFP/GFe）. Furthermore, after experimental seizures were induced with kainic acid in these CX3CRl-deficient mice, the expression of c-fos, a marker of neuronal activity, was reduced compared with wild-type mice. Collectively, the experimental findings indicate that the functional maturation of newborn neu- rons during hippocampal neurogenesis in adult mice is delayed by CX3CR1 deficiency.

In vitro Maturation of Tan Sheep Oocytes

[Objective] This study aimed to investigate the appropriate concentrations of follicle-stimulating hormone（FSH）, luteotropic hormone（LH） and estrodiol（E2） during in vitro maturation of Tan sheep oocytes. [Method] Tan sheep oocytes were divided into five groups for in vitro maturation culture： control group, FSH group（10,50, 100, 200 and 300 μg/ml FSH, respectively）, LH group（5, 10, 20, 50 and 100μg/ml LH, respectively）, E2group（5, 10, 25, 50 and 100 μg/ml E2, respectively）, and FSH ＋ LH group（100 μg/ml FSH ＋ 20 μg/ml LH）. The releasing rate of first polar bodies was analyzed. [Result] The maturation rate of Tan sheep oocytes in 100 μg/ml FSH ＋ 20 μg/ml LH group reached the highest（64.64%）, which was significantly higher than that in other four groups（P〈0.05）; among different FSH concentrations,100 μg/ml FSH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different LH concentrations, 20 μg/ml LH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different E2 concentrations, 50 μg/ml E2 was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）. [Conclusion] Under the experimental conditions, 100 μg/ml FSH ＋20 μg/ml LH was the most appropriate hormone combination for in vitro maturation of Tan sheep oocytes.

Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones （EEZ） during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22^nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length （ML） at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups （P〈0.05）. The waters adjacent to 1 l^S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.

Sperm maturation in the epididymis： a new look at an old problem

The osmotic challenges facing maturing spermatozoa and their responses to them are discussed in relation to the concept of sperm maturation, defined as the increased ability of more distally recovered epididymal spermatozoa to fertilize eggs when inseminated into the female tract. One explanation could be that the more distal cells are better able to regulate their volume, and reach the oviducts, as a consequence of uptake of epididymal osmolytes. Increased motility, zona binding and oolemma fusion capacities are also acquired within the epididymis and are necessary for those cells that finally arrive at the site of fertilization. （Asian J Androl 2007 July; 9： 533-539）

Probiotic metabolites from Bacillus coagulans GanedenBC30^(TM) support maturation of antigen-presenting cells in vitro

AIM:To study the effects of probiotic metabolites on maturation stage of antigen-presenting immune cells.METHODS:Ganeden Bacillus coagulans 30(GBC30) bacterial cultures in log phase were used to isolate the secreted metabolite(MET) fraction.A second fraction was made to generate a crude cell-wall-enriched fraction,by centrifugation and lysis,followed by washing.A preparation of MET was subjected to size exclusion centrifugation,generating three fractions:< 3 kDa,3-30 kDa,and 30-200 kDa and activities were tested in comparison to crude MET and cell wall in primary cultures of human peripheral blood mononuclear cell(PBMC) as a source of antigen-presenting mononuclear phagocytes.The maturation status of mononuclear phagocytes was evaluated by staining with monoclonal antibodies towards CD14,CD16,CD80 and CD86 and analyzed by flow cytometry.RESULTS:Treatment of PBMC with MET supported maturation of mononuclear phagocytes toward both macrophage and dendritic cell phenotypes.The biological activity unique to the metabolites included a reduction of CD14+ CD16+ pro-inflammatory cells,and this property was associated with the high molecular weight metabolite fraction.Changes were also seen for the dendritic cell maturation markers CD80 and CD86.On CD14dim cells,an increase in both CD80 and CD86 expression was seen,in contrast to a selective increase in CD86 expression on CD14bright cells.The co-expression of CD80 and CD86 indicates effective antigen presentation to T cells and support of T helper cell differentiation.The selective expression of CD86 in the absence of CD80 points to a role in generating T regulatory cells.CONCLUSION:The data show that a primary mechanism of action of GBC30 metabolites involves support of more mature phenotypes of antigen-presenting cells,important for immunological decision-making.

Selection of oocytes for in vitro maturation by brilliant cresyl blue staining： a study using the mouse model

Selecting oocytes that are most likely to develop is crucial for in vitro fertilization and animal cloning. Brilliant cresyl blue （BCB） staining has been used for oocyte selection in large animals, but its wider utility needs further evaluation. Mouse oocytes were divided into those stained （BCB＋） and those unstained （BCB-） according to their ooplasm BCB coloration. Chromatin configurations, cumulus cell apoptosis, cytoplasmic maturity and developmental competence were compared between the BCB＋ and BCB- oocytes. The effects of oocyte diameter, sexual maturity and gonadotropin stimulation on the competence of BCB＋ oocytes were also analyzed. In the large- and medium-size groups, BCB＋ oocytes were larger and showed more surrounded nucleoli （SN） chromatin configurations and higher frequencies of early atresia, and they also gained better cytoplasmic maturity （determined as the intracellular GSH level and pattern of mitochondrial distribution） and higher developmental potential after in vitro maturation （IVM） than the BCB-oocytes. Adult mice produced more BCB＋ oocytes with higher competence than the prepubertal mice when not primed with PMSG. PMSG priming increased both proportion and developmental potency of BCB＋ oocytes. The BCB＋ oocytes in the large-size group showed more SN chromatin configurations, better cytoplasmic maturity and higher developmental potential than their counterparts in the medium-size group. It is concluded that BCB staining can be used as an efficient method for oocyte selection, but that the competence of the BCB＋ oocytes may vary with oocyte diameter, animal sexual maturity and gonadotropin stimulation. Taken together, the series of criteria described here would allow for better choices in selecting oocytes for better development.

A novel ubiquitin carboxyl terminal hydrolase is involved in toad oocyte maturation

p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13sucl-agarose affinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accession number: AF 314091) indicated that it encodes a protein containing 224 amino-acids with about 55% identities and more than 70% positives to human, rat or mouse UCH-L1, and contains homological functional domains of UCH family. Anti-p28 monoclonal antibody, on injecting into the oocytes, could inhibit the progesterone-induced resumption of meiotic division in a dose-dependent manner. The recombinant protein p28 showed similar SDS/PAGE behaviors to the native one, and promoted ubiquitin ethyl ester hydrolysis, a classical catalytic reaction for ubiquitin carboxyl terminal hydrolases (UCHs). The results in this paper reveal that a novel protein, p28, exists in the toad oocytes, is a UCH L1 homolog, was engaged in the process of progesterone-induced oocyte maturation possibly through an involvement in protein turnover and degradation.

Screening and verification of the factors influencing somatic embryo maturation of Larix olgensis

With embryogenic callus of Larix olgensisis, we investigated the effects of inositol, glutamine, casein hydrolysate, carbohydrate, abscisic acid and silver nitrate concentration on the maturation of the somatic embryo.Three dominant factors emerged, and we developed a response surface model based on the Box-Behnken design.We defined the optimal conditions for the maturation of somatic embryos. The contents of abscisic acid, silver nitrate, sucrose and casein hydrolysis significantly affected the amount of maturing embryos, but inositol, maltose and glutamine had no effect. By establishing a response surface model with multiple factors, we predicted that the optimal number of L. olgensis somatic embryos was 204 ± 4 gon basal medium, containing 18.28 mg Labscisic acid,5.46 mg Lsilver nitrate and 82.67 g Lsucrose. In the verification experiments, the addition of 20 mg Labscisic acid, 5 mg Lsilver nitrate and 80 g Lsucrose to BM yielded an average of 202.06 somatic embryos per gram. These results should guide large-scale breeding of L. olgensis.

Comparative investigation on spindle behavior and MPF activity changes during oocyte maturation between gynogenetic and amphimictic crucian carp

The spindle behavior and MPF activity changes in the progression of oocyte maturation were investigated and compared with cytological observation and kinase assay between gynogenetic silver crucian carp and amphimictic colored crucian carp. MPF activity was measured by using histone H1 as phosphorylation substrate. There were two similar oscillatory MPF kinase activity changes during oocyte maturation in two kinds of fishes with different reproductive modes, but there existed some subtle difference between them. The subtle difference was that the first peak of MPF kinase activity was kept to a longerlasting time in the gynogenetic silver crucian carp than in the amphimictic colored crucian carp. It was suggested that the difference may be related to the spindle behavior changes, such as tripolar spindle formation and spindle rearrangement in the gynogenetic crucian carp.

The Longitudinal Sagittal Growth Changes of Maxilla and Mandible According to Quantitative Cervical Vertebral Maturation

To investigate the longitudinal sagittal growth changes of maxilla and mandible according to the quantitative cervical vertebral maturation （QCVM） for adolescents with normal occlusion, mixed longitudinal data were used. The samples included 87 adolescents aged from 8 to 18 y old with normal occlusion （32 males, 55 females） selected from 901 candidates. Sequential lateral cephalograms and hand-wrist films were taken once a year, lasting for 6 y. The longitudinal sagittal growth changes of maxilla and mandible according to QCVM were measured. There were some significant differences between maxilla and mandible according to QCVM. The sagittal growth change of maxilla showed a trend towards high velocity→decelerating velocity→completing velocity from QCVM stage Ⅰ to stage Ⅳ. The sagittal growth change of mandible showed a trend towards accelerating velocity→high velocity→decelerating velocity→completing velocity from QCVM stage Ⅰ to stage Ⅳ. With sagittal relationship, growth magnitude was almost the same between maxilla and mandible at QCVM stage Ⅰ . At stage Ⅱ the growth of mandible exceeded that of maxilla and growth in mandible continued at stages Ⅲ and IV, while the maxilla ceased to grow. Growth magnitude was greater and the growth duration was longer with male mandible. It is concluded that the longitudinal sagittal growth changes of maxilla and mandible on the basis of QCVM is of value in the orthodontic practice.