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Monosex populations in aquaculture is important to increase performance for subsequent food supply. Gynogenesis is the main tool to achieve monosex population within only one generation, since it provides only maternal inheritance. The present study aimed to achieve gynogenetic individuals of spotted catfish (Pimelodus maculatus), an important Neotropical species in which the female presents better growth performance. Sperm of yellowtail-tetra (Astyanax altiparanae) was UV-irradiated (80 mJ/cm2) in order to inactivate paternal genome. Afterwards, oocytes of P. maculatus were fertilized with the irradiated sperm and heat-shocked (38 °C for 2 min, 2 mpf) for diploidization by prevention of the release of the 2nd polar body. Diploid progenies derived from P. maculatus couples served as controls, and a non-treated haploid was also produced. Flow cytometric analysis and chromosome number obtained by cytogenetic analysis confirmed that gynogenetic individuals had the same number of chromosomes as the control group, indicating that sperm inactivation and diploidization was successful. Genotyping by microsatellite markers confirmed the maternal inheritance in these gynogenetics. Macroscopic visualization of the gonads revealed an increased number of females (n = 48) and only two males, suggesting a homogametic sex determination system (XX/XY). Finally, an efficient protocol for inducing meiotic gynogenesis in P. maculatus was established using irradiated sperm from A. altiparanae. This protocol can apply to produce monosex population and clonal lines in the P. maculatus species and can contribute for future studies in basic and applied sciences. [ABSTRACT FROM AUTHOR]

The use of wild species as a source of genetic variability is a valued tool in the framework of crop breeding. Hordeum chilense Roem. et Schult is a wild barley species that can be a useful genetic donor for sustainable wheat breeding which carries genes conferring resistance to some diseases or increasing grain quality, among others. Septoria tritici blotch (STB), caused by the Zymoseptoria tritici fungus, is one of the most important wheat diseases worldwide, affecting both bread and durum wheat and having a high economic impact. Resistance to STB has been previously described in H. chilense chromosome 4Hch. In this study, we have developed introgression lines for H. chilense chromosome 4Hch in durum wheat using interspecific crosses, advanced backcrosses, and consecutive selfing strategies. Alien H. chilense chromosome segments have been reduced in size by genetic crosses between H. chilense disomic substitution lines in durum wheat and durum wheat lines carrying the Ph1 deletion. Hordeum chilense genetic introgressions were identified in the wheat background through several plant generations by fluorescence in situ hybridisation (FISH) and simple sequence repeat (SSR) markers. An STB infection analysis has also been developed to assess STB resistance to a specific H. chilense chromosome region. The development of these H. chilense introgression lines with moderate to high resistance to STB represents an important advance in the framework of durum breeding and can be a valuable tool for plant breeders. [ABSTRACT FROM AUTHOR]

Motile Aeromonas Septicemia (MAS) disease caused by Aeromonas hydrophila is a common pathogen that attacks freshwater fish commodities, including triploid as the new strain of striped catfish. This study aimed to test the resistance of triploid striped catfish to MAS infection before being released to farmers as a new commodity to increase national striped catfish production. The test was carried out for two months at the Sukamandi Fish Breeding Research Institute, Subang by injecting A. hydrophila into triploid and diploid striped catfish. The challenge test was carried out by injecting the cultured A. hydrophila with a density of 107 cfu.mL-1 as much as 0.1 mL.ind-1 at fish intramuscularly in all treatments, while in the Control (-) treatment, 0.1 mL of PBS solution was injected.tail-1. The test striped catfish used for each treatment were 10 individuals measuring 9.23 - 9.65 cm, and weighing 7.1 - 9.23 g. Survival parameter data and blood description were analyzed quantitatively using Microsoft Excel 2010 and SPSS version 16.0 software with analysis of variance (ANOVA) at a 95% confidence interval. The results of re-characterization with biochemical tests showed that A. hydrophila were gramnegative, oxidase and catalase positive, motile, could fermentatively convert sugar, and could grow in blood media. The survival of triploid striped catfish after the test was 95%, total erythrocytes on day 7, and total leukocytes on the first day were significantly different from diploid striped catfish. Thus, it can be concluded that striped triploid striped catfish are more resistant to infection with A. hydrophila than diploid. [ABSTRACT FROM AUTHOR]

The use of wild species as a source of genetic variability is a valued tool in the framework of crop breeding. Hordeum chilense Roem. et Schult is a wild barley species that can be a useful genetic donor for sustainable wheat breeding which carries genes conferring resistance to some diseases or increasing grain quality, among others. Septoria tritici blotch (STB), caused by the Zymoseptoria tritici fungus, is one of the most important wheat diseases worldwide, affecting both bread and durum wheat and having a high economic impact. Resistance to STB has been previously described in H. chilense chromosome 4Hch. In this study, we have developed introgression lines for H. chilense chromosome 4Hch in durum wheat using interspecific crosses, advanced backcrosses, and consecutive selfing strategies. Alien H. chilense chromosome segments have been reduced in size by genetic crosses between H. chilense disomic substitution lines in durum wheat and durum wheat lines carrying the Ph1 deletion. Hordeum chilense genetic introgressions were identified in the wheat background through several plant generations by fluorescence in situ hybridisation (FISH) and simple sequence repeat (SSR) markers. An STB infection analysis has also been developed to assess STB resistance to a specific H. chilense chromosome region. The development of these H. chilense introgression lines with moderate to high resistance to STB represents an important advance in the framework of durum breeding and can be a valuable tool for plant breeders.

Summary: This study aimed to evaluate the ploidy and survival of larvae resulting from crosses between tetraploid females and diploid males of yellowtail tetra Astyanax altiparanae , both females (three diploids and three tetraploids) and males (n = 3 diploids). Breeders were subjected to hormonal induction with pituitary gland extract from common carp fish (Cyprinus carpio). Females received two doses at concentrations of 0.3 and 3.0 mg/kg −1 body weight and at intervals of 6 h. Males were induced with a single dose of 3.0 mg/kg −1 applied simultaneously with the second dose in females. Oocytes from each diploid and tetraploid female were fertilized with semen from the same male, resulting in two crosses: cross 1 (diploid male and diploid female) and cross 2 (diploid male and tetraploid female). The procedures were performed with separate females (diploid and tetraploid) and diploid males for each repetition (n = 3). For ploidy determination, 60 larvae from each treatment were analyzed using flow cytometry and cytogenetic analyses. As expected, flow cytometry analysis showed that progenies from crosses 1 and 2 presented diploid and triploid individuals, respectively, with a 100% success rate. The same results were confirmed in the cytogenetic analysis, in which the larvae resulting from cross 1 had 50 metaphase chromosomes and those from cross 2 had 75 chromosomes. The oocytes have a slightly ovoid shape at the time of extrusion. Diploid oocytes had a size of 559 ± 20.62 μm and tetraploid of 1025.33 ± 30.91 μm. Statistical differences were observed between eggs from crosses 1 and 2 (P = 0.0130). No significant differences between treatments were observed for survival at the 2-cell stage (P = 0.6174), blastula (P = 0.9717), gastrula (P = 0.5301), somite (P = 0.3811), and hatching (P = 0.0984) stages. In conclusion, our results showed that tetraploid females of the yellowtail tetra A. altiparanae are fertile, present viable gametes after stripping and fertilization using the 'dry method', and may be used for mass production of triploids. This is the first report of these procedures within neotropical characins, and which can be applied in other related species of economic importance. [ABSTRACT FROM AUTHOR]

Red sea bream Pagrus major is extremely important in the aquaculture of Japan. The breeding of red sea bream, which has a history of more than half a century, can be divided into three main categories. The first is selective breeding. The Aquaculture Research Institute, Kindai University, began breeding fast-growing red sea breams in the early 1960s through mass selection. I summarized the results of the selection and characteristics of the fish in the 1990s. The second is breeding through chromosome manipulation and sex control. Two types of gynogenetic diploids (G2N) were artificially induced. Although growth and survival of G2N were inferior, the growth of heterozygous clones produced by mating G2N was comparable to normal diploids. The sex differentiation process and the induction condition of all-male groups by 17α-methyltestosterone treatment were clarified, and the percentage of females could be increased to more than 85%. The third is breeding through genetic manipulation. We first developed the microinjection method, and succeeded in increasing the percentage of edible ratio by deleting the function of myostatin gene by genome editing. Combining new technologies, such as genome editing, with the existing breeding methods mentioned above would result in faster and more effective breeding. [ABSTRACT FROM AUTHOR]

Abstract Bata (Labeo bata), an indigenous, freshwater minor carp, is a great delicacy in Bangladesh. In its natural fishery, bata contributes significantly to the health and nutritional security of a large section of the fisher communities in Bangladesh. However, it is not a popular farmed fish because of its small size and slow growth rate. The induction of triploidy, aimed at providing faster growth and larger body size, could be appropriate for L. bata to enhance its aquaculture potential. In the present study, we induced triploidy in L. bata by applying heat shock on fertilised eggs (that were maintained at the ambient temperature of 26–28°C), 3 to 5 min post fertilisation and for durations ranging from 1 to 2 min. Four different temperatures, namely, 38, 39, 40 and 41°C, were tested as heat shock treatments. The optimum treatment combination for triploidy induction in L. bata was found to be 39°C for the 1 min duration, 3 min after fertilisation, yielding 100% triploidy. Karyotyping revealed 72 chromosomes in the triploid fish (3n), whereas the diploid control (2n) had 48 chromosomes. The growth performance of the triploid hatchlings was compared against the diploid control in experimental ponds. After 12 weeks of rearing, the triploid fish were significantly heavier (p

Triploidy induction is one of the promising techniques to increase growth in aquaculture and may minimize the negative impacts that escaped fish may present to the environment. The aim of this study was to evaluate the efficiency of cold shocks in producing triploid individuals using a Neotropical migratory fish species, the curimba (Prochilodus argenteus). Cold shocks (4ºC) were applied at different times (5, 10, and 12 min) after fertilization and for varying shock durations (10, 15, 20, and 25 min). Survival rates were not different between triploid and diploid controls at 43 days after hatching, at the end of the juvenile stage. The best parameters for triploidy induction were cold shock (4°C), applied 5 min after fertilization for 25 min, resulting in 100% triploid fish. This triploidy induction protocol is simple and can be used in widespread aquaculture productions. [ABSTRACT FROM AUTHOR]

Summary: Gynogenesis is a chromosomal manipulation technique where an offspring is generated exclusively from maternal inheritance. In the yellowtail tetra (Astyanaxaltiparanae) almost all gynogenetic fish were females, suggesting a genetic sex determination system of XX/XY. However, due to environmental (e.g. temperature) or unknown genetic factors, the rise of males are described. Therefore, the aim of this study was to analyze the reproductive parameters of spontaneously gynogenetic males. The parameters analyzed were spermatozoon viability, motility and ploidy. Additionally, the gonads were processed for histology and the genetic inheritance confirmed by genotyping. Sperm parameters of gynogenetic males did not show differences when compared with semen of normal males. These data supports that gynogenetic males presents fertilization capacity and can be used for future studies of chromosome manipulation or possible production of monosex populations in A. altiparanae. [ABSTRACT FROM AUTHOR]

Summary: Triploidization plays an important role in aquaculture and surrogate technologies. In this study, we induced triploidy in the matrinxã fish (Brycon amazonicus) using a heat-shock technique. Embryos at 2 min post fertilization (mpf) were heat shocked at 38°C, 40°C, or 42°C for 2 min. Untreated, intact embryos were used as a control. Survival rates during early development were monitored and ploidy status was confirmed using flow cytometry and nuclear diameter analysis of erythrocytes. The hatching rate reduced with heat-shock treatment, and heat-shock treatments at 42°C resulted in no hatching events. Optimal results were obtained at 40°C with 95% of larvae exhibiting triploidy. Therefore, we report that heat-shock treatments of embryos (2 mpf) at 40°C for 2 min is an effective way to induce triploid individuals in B. amazonicus. [ABSTRACT FROM AUTHOR]

Summary: The optimum distance and duration of ultraviolet (UV) irradiation for the complete inactivation of African catfish Clarias gariepinus egg nucleus was investigated in this study. The UV light was suspended above the unfertilized eggs at four distances (5, 10, 20 and 30 cm) and for five durations (1, 2, 3, 4 and 5 min). Then, the irradiated eggs were activated with sperm from diploid C. gariepinus and cold shocked at 5°C for 5 min just moments before cell cleavage. Ploidy analysis was performed using karyotype chromosome counting. The results obtained suggested that the further the distance, the better the hatchability rate, however prolonged duration seemed to significantly reduced hatchability. All treatments with surviving progenies at the end of the study showed evidence of successfully diploid gynogen (2n = 56) induction at different percentages. However, the optimal protocol that gave a moderately high hatchability/survival rate and completely induced gynogens was exposure of the eggs to UV irradiation at 20 cm for 1 min. It was concluded that the distance and duration of UV irradiation affects gynogenetic induction in African catfish C. gariepinus. [ABSTRACT FROM AUTHOR]

Summary: The aim of this study was to evaluate different post-shock temperatures for tetraploid induction in the yellowtail tetra Astyanax altiparanae. Newly fertilized eggs were divided into four groups, three were submitted to heat shock (40°C for 2 min) at 24 min post-fertilization (mpf) and another group remained without shock (control). Groups submitted to temperature shock were further separated at the following temperatures: 22°C, 26°C and 28°C. Survival among embryonic development was counted and at hatching the ploidy was analyzed by flow cytometry. The results showed that the post-shock temperature affects the parameters analyzed and, therefore, must be considered for optimization of the production of tetraploid in A. altiparanae. Those data are innovative and could be used in future studies of basic biology in this species. [ABSTRACT FROM AUTHOR]

Triploidization is a technique to produce sterile fish on a large scale. In the spotted catfish Pimelodus maculatus, sterile fish serve as a host of germ cell transplantation for subsequent reconstitution of endangered catfish species. This study aimed to establish an efficient protocol for triploidization in P. maculatus using temperature shock. In this study, we tested the efficacy of heat shock treatments (37 °C, 38 °C, and 39 °C) applied at 2 min post-fertilization (mpf) for the duration of 2 min. Intact embryos served as diploid control. Ploidy status was confirmed by flow cytometry, characterization of erythrocytes nuclei, and karyotyping. Developmental stages were verified at cleavage, blastula, gastrula, somite, and hatching stages, as well as the percentages of normal and abnormal larvae. No significant difference was observed between the temperature treatments for percentage of unfertilized oocytes (P = 0.1834), 2-cell stage (P = 0.2348), blastula (P = 0.2972), hatching (P = 0.0668), and abnormal larvae (P = 0.6177). Heat shock decreased the survival at the blastula stage (P = 0.0178), somite (P = 0.0469), and the percentage of abnormal larvae (P = 0.0261). All treatments presented high percentages of triploid individuals, and the highest values were observed for heat shock at 38 °C (96.7 %). Based on the results described above, an efficient protocol for triploidization in P. maculatus was established using heat shock (38 °C) at 2 mpf for 2 min. [ABSTRACT FROM AUTHOR]

Tetraploid fish are important for mass production of triploids in polyploid breeding. In this study, we reported a novel protocol for artificial induction of tetraploidy by a combination of cold shock and hydrostatic pressure administered to gynogenetically developed eggs in Japanese flounder Paralichthys olivaceus. The induction was carried out by activating the eggs with UV-irradiated sperm of red sea bream Pagrus major, administering a cold shock (0°C, 5 to 45 min) 3 min after fertilization to inhibit second polar body exclusion, incubating the eggs for 60 min at 17°C, and treating them with a 650 kg/cm2 hydrostatics pressure shock for 6 min. We named the embryos gyno-tetraploids that developed from eggs after such treatments. The hatching rate of the gyno-tetraploids ranged from 20.99%±3.66% to 36.01%±2.79%, and the tetraploid rate ranged from 80.00% to 100.00%. All-maternal inheritance was verified using 6 high-recombination-rate microsatellite markers. This method successfully induced gyno-tetraploidy. The successful induction of gyno-tetraploidy lays the foundation for triploidization of new varieties with improved economic traits of interest that can benefit commercial culture. [ABSTRACT FROM AUTHOR]

We report for the first time, a comparison of two approaches for artificially induced triploidy in zebrafish (Danio rerio) using cold shock and heat shock treatments. Of the two methods, heat shock treatment proved more effective with a triploid production rate of 100% in particular females. Subsequently, triploid zebrafish larvae were used as recipients for intraperitoneal transplantation of ovarian and testicular cells originating from vas:EGFP strain in order to verify their suitability for surrogate reproduction. Production of donor-derived sperm was achieved in 23% of testicular cell recipients and 16% of ovarian cell recipients, indicating the suitability of triploids as surrogate hosts for germ cell transplantation. Success of the transplantation was confirmed by positive GFP signal detected in gonads of dissected fish and stripped sperm. Germline transmission was confirmed by fertilization tests followed by PCR analysis of embryos with GFP specific primers. Reproductive success of germline chimera triploids evaluated as fertilization rate and progeny development was comparable to control groups. • Zebrafish triploids can be produced by a simple heat shock treatment. • Triploids are convenient candidates for surrogate reproduction in zebrafish. • Donor-derived sperm was produced after germ cell transplantation into triploids. • Fertility performance of triploid germline chimera is similar to control males. [ABSTRACT FROM AUTHOR]

Here, we explored cold‐shock‐induced haploid androgenesis in Japanese pufferfish (Takifugu rubripes) and analysed chromosomes by fluorescence in situ hybridization (FISH), single nucleotide polymorphism (SNP) in sex determination locus and microsatellite genotypes to verify all‐male inheritance. We also observed early embryonic development to have an insight into the cytological mechanism of cold‐shock‐induced gynogenesis. The chromosome number of control group was diploid (2n = 44), while in cold‐shock group haploid (1n = 22) and triploid (3n = 66) embryos were detected. Cellular DNA content flow cytometry showed that the rate of haploid induction was 90%. One signal of nucleolar organizing region (NOR) was detected by silver nitrate staining and FISH using rDNA probe in androgenetic haploids from cold‐shock group. SNP analysis revealed that about half of haploid embryos examined had the G genotype indicating male‐specific Y chromosome. Microsatellite genotyping showed that 26 out of 29 haploid embryos from cold‐shock group exclusively inherited paternally derived genotypes. Cytological observation revealed that both second polar body and egg nucleus were located on the blastodisc surface at 60 min post fertilization in cold‐shock group, suggesting simultaneous extrusion of both nuclei. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the growth, carcass yield, fatty acid composition, and reproductive parameters of diploid and triploid Astyanax altiparanae . Triploidization was induced by heat shock (40 °C for 2 min) 2 min after fertilization. Fish were reared for 175 days from fertilization. Triploid females showed lower proportion of saturated and poly-unsaturated fatty acids and higher amount of mono-unsaturated fatty acids than diploids. They were sterile, with immature gonads, and showed higher carcass yield than diploid females, which exhibited higher gonadosomatic indices. Triploid and diploid males showed similar gonad morphology, although diploid males produced greater numbers of spermatozoa. All males exhibited the secondary sex characteristic of spines in the pelvic and anal fins. Fatty acid composition and growth were similar in triploid and diploid males. Triploidy did not ensure sterility in males, but triploid females were sterile and had increased carcass yield, and may be used in aquaculture to increase the production of A. altiparanae. Statement of relevance To our knowledge, this is the first study addressing the effect of triploid induction on growth parameters of a neotropical species. The important results for carcass yield and sterility in female triploid will improve the production of A. altiparane , as this species is being used as live-bait for sport fishing and direct consumption. [ABSTRACT FROM AUTHOR]

Androgenesis is a useful manipulation to fix male-specific genetic traits as well as to restore the genotypes of cryopreserved sperm, and it has been induced by the genetic inactivation of the egg nucleus with gamma-, X- or UV-ray irradiation before fertilization. Recently, a technique for cold-shock induced androgenesis was developed in a freshwater species, the loach, Misgurnus anguillicaudatus , in which viable androgenetic diploids and doubled haploids (DHs) were successfully produced by the fertilization of diploid sperm and chromosome doubling by heat-shock treatment, respectively. This technique was immediately applied for cloning in the zebrafish, Danio rerio . Here, we reported the first successful induction of androgenetic development by means of cold-shock treatment (at 0 °C for 15 min) just after the fertilization (within 10 s) of eggs in a marine aquaculture fish species, the Japanese flounder, Paralichthys olivaceus . Then, androgenetic embryos thus generated were subjected to hydrostatic pressure treatment (650 kg/cm 2 , 6 min) after incubation at 17 °C so as to produce DHs by chromosome doubling. The yield rate of putative DHs, which was estimated as the frequency of diploid larvae at the first feeding stage in relation to the total eggs used, ranged from 0.81% to 1.79%. The complete homozygosity of these putative DHs was genetically verified using 36 microsatellite markers that covered 24 linkage groups of Japanese flounder. Thus, an androgenetic clonal line was produced with the sperm of a mito-gynogenetic DH male by using cold-shock and subsequent hydrostatic pressure-shock treatments. Statement of relevance The results of our manuscript confirm the broad applicability of the cold-shock induced androgenesis method in commercially important marine fish species. [ABSTRACT FROM AUTHOR]

Production of sterile triploid red tilapia [ Oreochromis mossambicus (Mozambique tilapia); Peters, 1852 × Oreochromis niloticus (Nile tilapia); Linnaeus, 1758] is an effective strategy to overcome their prolific breeding. Optimal conditions for cold-shock induction of triploidy in red tilapia were investigated by experimentally examining two variables: appropriate temperature of the shock and duration of shock treatment. A constant time after insemination of 4 min was used to determine the best combination of temperature (6, 7, 8, 9, 11, 13, 15 °C) with different durations of shock (10, 20, 30, 40, 50 min) with resultant ploidy level verified karyotypically. Shock duration for 30 min at a temperature of 9 °C was found most effective in producing maximum triploidy (98.7 %) with higher rates of hatching (63.2 %) and survival up to yolk-sac stage (75.8 %). The chromosome count confirmed that triploid percentages were higher when cold shock was used for longer durations at each temperature; however, hatching rates were generally decreased. The maximum triploid yield (82.1 %) obtained was higher than the yield obtained using heat shock (72.7 %) in red tilapia previously. The application of the results of this study has the potential to greatly improve the production of triploid red tilapia in commercial aquaculture. [ABSTRACT FROM AUTHOR]

Abstract: This study seeks to determine the best method for preventing the second body (PBII) extrusion as a means to induce triploidy in the black tiger shrimp Penaeus monodon. Chemical (cytochalasine-B and 6-dimethylaminopurine) and temperature (heat and cold) shocks were applied to newly fertilized eggs. Cold shock that was administered at 8°C, for 10min at 8min post-spawning, was the best method for PBII triploidy induction, as evidenced by the highest percentage of forming three pronuclei in syngamy. Therefore, cold shock induction was employed to further explore the advantage of triploid over diploid shrimp. After hatching of the cold-shocked eggs, the larvae were allowed to reach juvenile and adult levels of development. The number and amount of chromosomes were determined in juveniles and adult stages, using Fluorescence Activating Cell Sorting methods, by which the shrimp were divided into diploid and triploid groups. At day 150 in culture, the average body weight of the triploid females (35.2±3.2g) and triploid males (31.5±3.5g) was significantly higher (P <0.0001) than that of their diploid counterparts (24.5±0.5g for females and 23.1±3.8g for males), having a ratio of 2 females:1 male for triploid shrimp, and 2 females:3 males for diploid shrimp. These results reveal the advantages of growing triploid over diploid P. monodon, and its feasibility for commercial production. [Copyright &y& Elsevier]

Abstract: Mitotic gynogenetic diploid or doubled haploid Japanese flounder Paralichthys olivaceus were produced by activating eggs with UV irradiated sperm of red sea bream (Pagrus major), followed by hydrostatic pressure treatment to block the first mitotic division. To verify the doubled haploid, we measured the homozygosity of 21 maternally heterozygous microsatellite loci that are located in the telomeric region of chromosomes. These 21 loci have large marker-centromere distances of 43 to 50cM estimated from four meiotic gynogenetic diploid lines, suggesting the location at telomeric regions of chromosomes. These 21 loci cover 16 out of the total 24 linkage groups of Japanese flounder. Microsatellite genotyping of these 21 markers in four mitotic gynogentic diploid lines shows that 75% (58 out of 77) individuals are homozygous at all 21 loci, indicating doubled haploids. The other 25% are heterozygous at 1 to 13 loci, probably representing spontaneously occurring meiotic gynogenetic diploids. These results demonstrate the high efficiency of generating doubled haploids in just one generation by mitotic gynogenesis. We have used these doubled haploids to successfully generate clonal lines via a second round of gynogenesis. [Copyright &y& Elsevier]

Triploidy interferes with gametogenesis in all fish species tested so far. In fish it results in complete female sterility however, males are still able to develop testis. The reason why sterility levels in triploid fishes differ among species and between sexes is unclear. In the present study the reproductive capacity of triploid males of tench was studied. Flow cytometry revealed sperm cells of triploids to be largely aneuploid with high mosaic DNA, oscillating from haploid DNA to diploid DNA content. Analysis of variance showed an insignificant influence of ploidy level on the percentage of motile spermatozoa, as well as on spermatozoa velocity. Experimental crosses between normal diploid female and triploid males resulted in the appearance of triploid progeny, which exhibited genotypes composed of microsatellite alleles inherited from the founder female and additional allele derived from the donor male. We can conclude that the triploid males analysed in the present study were capable to fertilize eggs derived from diploid females. [ABSTRACT FROM AUTHOR]

A fundamental issue in biotechnology is how to breed useful strains of microorganisms for efficient production of valuable biomaterials. On-going and more recent developments in gene manipulation technologies and chromosomal and genomic modifications in particular have facilitated important contributions in this area. “Chromosome manipulation technology” as an outgrowth of “gene manipulation technology” may provide opportunities for creating novel strains of organisms with a variety of genomic constitutions. A simple and rapid chromosome splitting technology called “PCR-mediated chromosome splitting” (PCS) that we recently developed has made it possible to manipulate chromosomes and genomes on a large scale in an industrially important microorganism, Saccharomyces cerevisiae. This paper focuses on recent advances in molecular methods for altering chromosomes and genome in S. cerevisiae featuring chromosome splitting technology. These advances in introducing large-scale genomic modifications are expected to accelerate the breeding of novel strains for biotechnological purposes, and to reveal functions of presently uncharacterized chromosomal regions in S. cerevisiae and other organisms. [ABSTRACT FROM AUTHOR]

The aim of this study was to establish effective procedures for chromosome manipulation in greenling Hexagrammos otakii Jordan et Starks, which has enormous aquacultural potential. To accomplish this, temperature-dependent measurements of the mitotic intervals (τ0) were carried out. The τ0 in this fish was determined by averaging the duration of the first and third embryonic divisions at temperatures ranging 5–25°C. At higher temperatures, eggs developed faster and underwent more identical development. For greenling, τ0 were 341.1 ± 3.60 min at 5°C, 275.5 ± 4.53 min at 10°C, 189.7 ± 6.93 min at 15°C, 99.2 ± 8.27 min at 20°C and 34.2 ± 8.74 min at 25°C. There were strong, negative correlations between the τ0 and water temperatures at all temperatures studied ( Y = −79.3 X + 425.3, R2 = 0.9968, where Y is the mitotic interval and X is the temperature). [ABSTRACT FROM AUTHOR]

The genetic algorithm optimization technique for optical filter design is applied to two starting populations, an inverse Fourier transform population and a random population. The refractive index profiles after convergence, and the transmittance of the filter outside the region of support, are markedly different in the two cases. The Fourier filter has lower sidelobes and fails gracefully outside the region of support whereas the random filter fails catastrophically in this wavelength region. The ripple in the passband is higher for the random filter. Furthermore, the average value of refractive index profile and the excursion in refractive index are much larger for the filter generated with the random starting population. However, most of the drawbacks of the random starting population are eliminated by chromosome manipulation in the spatial frequency domain. The fitter properties after this intervention approximate those of the Fourier filter [ABSTRACT FROM PUBLISHER]

Crosses between octoploid and hexaploid triticales have been made in breeding programs for several years. From an analysis of the progeny of such crosses where selections for an octoploid-like phenotype had been made, it was established that 149 out of 150 lines were hexaploid in chromosome number. C-banding and in situ hybridization demonstrated that all but five of the 62 lines analyzed in detail contained visible chromosomes or segments from the D genome. Only four lines had D-genome chromosomes replacing rye chromosomes. All of the remaining 53 D-genome substitutions involved the replacing of wheat chromosomes from either the A or B genomes. This establishes the ease with which D-genome genes can be placed into triticale without the loss of rye chromosomes. [ABSTRACT FROM AUTHOR]

Androgenesis is a potentially valuable technique for recovering fish from gene banks composed of cryopreserved sperm, developing inbred lines, and analyzing patterns of inheritance. The procedure for producing diploid organisms whose nuclear DNA is wholly of paternal origin is dependent on: (1) the denucleation of 'host' eggs, and (2) the inhibition of the first mitotic division in order to double the haploid sperm chromosome complement following fertilization of host eggs. Denucleation of tilapia ( Oreochromis niloticus L.) eggs was carried out using UV irradiation. Treatment durations of 5-8 min (total dose of 450-720 J/m) produced acceptable yields of viable denucleated eggs [22.9±1.6% (±SE) of controls] as estimated by the survival of haploid androgenetic tilapia to 48 h post-fertilization. Successful mitotic inhibition was accomplished using a heat-shock of 42.5 °C for 3-4 min, applied at 2.5-min intervals from 22.5 to 30 min post-fertilization (mpf). The mean survival of androgenetic diploid fish to yolk-sac absorption for treatment groups varied from 0.4% to 5.3%, relative to the controls. Differences in the suceptibility of eggs from different females to UV irradiation were a significant factor in the overall yield of androgenetic diploids. Paternal effects did not significantly influence the androgenetic yield, suggesting that individual males would not be selected against. For comparative purposes mitotic gynogenetic 'mitogyne' diploids were produced from UV-irradiated sperm. Mean survival to yolk-sac absorption varied from 0.5% to 10.64%, relative to controls. Similar optima for androgenetic and gynogenetic induction were found in the period 25-27.5 mpf (minutes post-fertilization). Induction treatments would appear to be operating on the same developmental events in both these techniques, and the results suggest that the UV irradiations used do relatively little damage to the eggs beyond nuclear inactivation. The results indicate that the production of androgenetic O. niloticus is possible on a consistent basis and that the application of this technique may be useful in quantitative and conservation genetics. [ABSTRACT FROM AUTHOR]

Tetraploid fish are an important source of diploid gametes for polyploid production, and they can be induced by inhibition of the first mitotic cell division. Dispite its potential, very few protocols regarding tetraploidization and subsequent application to mass production of triploid fish for aquaculture exist. In the yellowtail tetra Astyanax altiparanae , triploids present sterility and increased carcass yield, suggesting the generation of tetraploid for large-scale production of such triploids. In this study, the efficacy of heat shock treatments (40° for 2 min) at 16, 18, 20, 22, 24, and 26 min post-fertilization (mpf) at an incubation temperature of 22 °C were compared on tetraploid induction of A. altiparanae. Ploidy status was confirmed by flow cytometry, karyotyping, and nuclear diameter of erythrocytes. Afterwards, sperm parameters and fertility capacity of tetraploid males were evaluated. The results showed that heat shock decreased the hatching rate, especially at 22 (19.1 ± 9.6%), 24 (16.0 ± 9.1%), and 26 mpf (10.3 ± 6.2%) in comparison with the control group (62.2 ± 7.7%). The flow cytometric analysis showed that the control group and the treatments with heat shock at 16 and 18 mpf presented only diploid individuals. However, from 20 mpf onwards, tetraploid individuals were observed, and the highest percentage arose at 26 mpf (94.55%). When mature, tetraploid males are capable of producing diploid spermatozoa with fertilization capacity, generating a 100% triploid offspring. The results indicate that the heat shock treatment at 26 mpf (40 °C for 2 min) is optimum for tetraploid induction in the A. altiparanae. Additionally, tetraploid mature males generated diploid spermatozoa and can be used to mass production of triploid fish. The current data are the first report of tetraploids in family Characidae, presenting an application in basic and applied sciences. • Tetraploidization were optimized in Astyanax altiparanae by heat-shock (40 °C; 2 min) at 26 min post-fertilization. • High percentages (94.55%) of tetraploids were obtained. • Tetraploid males are viable and can produce diploid gametes. • 100% triploid offspring were generated with diploid spermatozoa from tetraploid males. • This was the first protocol of induced tetraploids in Neotropical Characins. [ABSTRACT FROM AUTHOR]