Birth of offspring from spermatid or somatic cell by co-injection of PLCζ-cRNA.

Artificial oocyte activation is important for assisted reproductive technologies, such as fertilization with round spermatids (ROSI) or the production of cloned offspring by somatic cell nuclear transfer (SCNT). Recently, phospholipase Cζ (PLCζ)-cRNA was used to mimic the natural process of fertilization, but this method required the serial injection of PLCζ-cRNA and was found to cause damage to the manipulated oocytes. Here we tried to generate offspring derived from oocytes that were fertilized using round spermatid or somatic cell nuclear transfer with the co-injection of PLCζ-cRNA. After co-injecting round spermatids and 20 ng/µL of PLCζ-cRNA into the oocytes, most of them became activated, but the activation process was delayed by more than 1 h. With the co-injection method, the rate of blastocyst formation in ROSI embryos was higher (64%) compared with that of the serial injection method (55%). On another note, when SCNT was performed using the co-injection method, the cloned offspring were obtained with a higher success rate compared with the serial-injection method. However, in either ROSI or SCNT embryos, the birth rate of offspring via the co-injection method was similar to the Sr activation method. The epigenetic status of ROSI and SCNT zygotes that was examined showed no significant difference among all activation methods. The results indicated that although the PLCζ-cRNA co-injection method did not improve the production rate of offspring, this method simplified oocyte activation with less damage, and with accurate activation time in individual oocytes, it can be useful for the basic study of oocyte activation and development.

Postzygotic isolation varies by ploidy level within a polyploid complex.

Whole genome duplication is considered to be a significant contributor to angiosperm speciation due to accumulation of rapid, strong interploid reproductive isolation. However, recent work suggests that interploid reproductive isolation may not be complete, especially among higher order cytotypes. This study evaluates postzygotic reproductive isolation among three cytotypes within a polyploid complex. We conducted reciprocal crosses using two diploid and two hexaploid populations each crossed to tetraploid populations spanning the geographic and phylogenetic range of the Campanula rotundifolia polyploid complex. Interploid and intrapopulation crosses were scored for fruit set, seed number, germination proportion and pollen viability. Postzygotic isolation was calculated for each cross as the product of these fitness components. A subset of offspring was cytotyped via flow cytometry. Postzygotic isolation was significantly lower in tetraploid-hexaploid crosses than diploid-tetraploid crosses, mostly due to substantially higher germination among tetraploid-hexaploid crosses. Tetraploid-hexaploid crosses produced pentaploids exclusively, whereas diploid-tetraploid crosses produced both triploids and tetraploids in high frequencies. Postzygotic isolation was weaker among higher order polyploids than between diploids and tetraploids, and unreduced gametes may facilitate diploid-tetraploid reproduction. This incomplete postzygotic isolation could allow ongoing interploid gene flow, especially among higher order polyploids, which may slow divergence and speciation in polyploid complexes.

Pollen performance traits reveal prezygotic nonrandom mating and interference competition in Arabidopsis thaliana.

PREMISE: The lack of ability to measure pollen performance traits in mixed pollinations has been a major hurdle in understanding the mechanisms of differential success of compatible pollen donors. In previous work, we demonstrated that nonrandom mating between two accessions of Arabidopsis thaliana, Columbia (Col) and Landsberg (Ler), is mediated by the male genotype. Despite these genetic insights, it was unclear at what stage of reproduction these genes were acting. Here, we used an experimental strategy that allowed us to differentiate different pollen populations in mixed pollinations to ask: (1) What pollen performance traits differed between Col and Ler accessions that direct nonrandom mating? (2) Is there evidence of interference competition? METHODS: We used genetically marked pollen that can be visualized colorimetrically to quantify pollen performance of single populations of pollen in mixed pollinations. We used this and other assays to measure pollen viability, germination, tube growth, patterns of fertilization, and seed abortion. Finally, we assessed interference competition. RESULTS: In mixed pollinations on Col pistils, Col pollen sired significantly more seeds than Ler pollen. Col pollen displayed higher pollen viability, faster and greater pollen germination, and faster pollen tube growth. We saw no evidence of nonrandom seed abortion. Finally, we found interference competition occurs in mixed pollinations. CONCLUSION: The lack of differences in postzygotic processes coupled with direct observation of pollen performance traits indicates that nonrandom mating in Arabidopsis thaliana is prezygotic, due mostly to differential pollen germination and pollen tube growth rates. Finally, this study unambiguously demonstrates the existence of interference competition.

The Efficacy of Chinese Medicinal Herbs towards Grape Phylloxera (Daktulosphaira vitifoliae Fitch) (Hemiptera, Phylloxeridae).

Bio-insecticidal effects of seven Chinese medicinal herbs on mortality, fecundity, developmental periods and life table parameters of the grape phylloxera were investigated. In an excised root bioassay experiment aqueous extracts from seven Chinese medicinal herbs increased grape phylloxera first instar mortality (26.00-38.50%) compared to other instars. The intrinsic rate of increase (rm), finite rate of increase (λ), fecundity rate and net reproductive rate (R0) were significantly reduced by A. bidentata, A. tataricus, O. basilicum, P. frutescens and N. cataria. In a glasshouse pot trial, eggs, nymphs, adults and total population were significantly reduced before population establishment compared to those after its population established, by A. bidentata, A. tataricus and O. basilicum. Overall, A. bidentata, A. tataricus and O. basilicum can be used to suppress all life-stages of grape phylloxera.

[Peculicidal activity of plant essential oils and their based preparations].

The peculicidal activity of eight plant essential oils in 75% isopropyl alcohol was in vitro investigated. Of them, the substances that were most active against lice were tea tree (Melaleuca), eucalyptus, neem, citronella (Cymbopogon nardus), and clove (Syzygium aromaticum) oils; KT50 was not more than 3 minutes on average; KT95 was 4 minutes. After evaporating the solvent, only five (tea tree, cassia, clove, anise (Anisum vulgare), and Japanese star anise (Illicium anisatum) oils) of the eight test botanical substances were active against lice. At the same time, KT50 and KT95 showed 1.5-5-fold increases. Citronella and anise oils had incomplete ovicidal activity. Since the lice were permethrin-resistant, the efficacy of preparations based on essential oils was much higher than permethrin.

Investigation into the mechanism of action of essential oil of Pistacia integerrima for its antiasthmatic activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Pistacia integerrima J.L. Stewart ex Brandis locally known as Karkatashringi is an important medicinal plant whose galls are valued in traditional medicine used in India for the treatment of asthma, chronic bronchitis, phthisis, diarrhea, fever, other ailments for the respiratory tract, and as antispasmodic, carminative, antiamoebic and anthelmintic. However, in vitro and in vivo investigations providing new insights into its pharmacological properties have not been thoroughly investigated yet. The present investigation aimed to elucidate the probable mechanism of antiasthmatic action of essential oil of Pistacia integerrima J.L. Stewart ex Brandis galls (EOPI). METHODS: EOPI was tested using in vitro studies such as antioxidant activity, mast cell degranulation, angiogenesis, isolated guinea pig ileum preparation and soyabean lipoxidase enzyme activity. In vivo studies included lipopolysaccharide-induced bronchial inflammation in rats and airway hyperresponsiveness in ovalbumin in sensitized guinea pigs using spirometry. RESULTS: EOPI (5-30 µg/ml) inhibits 5-lipoxidase enzyme activity with IC50 of 19.71 µg/ml and DPPH scavenging activity up to 100 µg/ml with maximum inhibition of 44.93 ± 2.53% at 100 µg/ml. Pre-treatment with EOPI inhibited erythropoietin-induced angiogenesis. It showed dose dependent (10, 30 and 100 µg/ml) anti-allergic activity by inhibiting compound 48/80 induced mast cell degranulation to an extent 19.08 ± 0.47%. The finding that essential oil induced inhibition of transient contraction of acetylcholine in calcium free medium, and relaxation of S-(-)-Bay 8644-precontracted isolated guinea pig ileum jointly suggests that the L-subtype Cav channel is involved in spasmolytic action of EOPI. Treatment with EOPI dose dependently (7.5, 15 and 30mg/kg i.p.) inhibited lipopolysaccharide-induced increase in total cell count, neutrophil count, nitrate-nitrite, total protein, albumin levels in bronchoalveolar fluid and myeloperoxidase levels in lung homogenates. Roflumilast was used as a standard. EOPI reduced the respiratory flow due to gasping in ovalbumin sensitized guinea pigs. CONCLUSION: The study demonstrates the effectiveness of essential oil of Pistacia integerrima J.L. Stewart ex Brandis galls in bronchial asthma possibly related to its ability to inhibit L-subtype Cav channel, mast cell stabilization, antioxidant, angiostatic and through inhibition of 5-lipoxygenase enzyme.

Effect of structurally related flavonoids from Zuccagnia punctata Cav. on Caenorhabditis elegans.

Zuccagnia punctata Cav. (Fabaceae), commonly called jarilla macho or pus-pus, is being used in traditional medicine as an antiseptic, anti-inflammatory and to relieve muscle and bone pain. The aim of this work was to study the anthelmintic effects of three structurally related flavonoids present in aerial parts of Z. punctata Cav. The biological activity of the flavonoids 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2´,4´-dihydroxychalcone (DHC) was examined in the free-living nematode Caenorhabditis elegans. Our results showed that among the assayed flavonoids, only DHC showed an anthelmintic effect and alteration of egg hatching and larval development processes in C. elegans. DHC was able to kill 50% of adult nematodes at a concentration of 17 µg/mL. The effect on larval development was observed after 48 h in the presence of 25 and 50 µg/mL DHC, where 33.4 and 73.4% of nematodes remained in the L3 stage or younger. New therapeutic drugs with good efficacy against drug-resistant nematodes are urgently needed. Therefore, DHC, a natural compound present in Z. punctata, is proposed as a potential anthelmintic drug.

Anti-inflammatory effects of fish oil in ovaries of laying hens target prostaglandin pathways.

BACKGROUND: An effective way to control cancer is by prevention. Ovarian cancer is the most lethal gynecological malignancy. Progress in the treatment and prevention of ovarian cancer has been hampered due to the lack of an appropriate animal model and absence of effective chemo-prevention strategies. The domestic hens spontaneously develop ovarian adenocarcinomas that share similar histological appearance and symptoms such as ascites and metastasis with humans. There is a link between chronic inflammation and cancer. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. PGE2 exerts its effects on target cells by coupling to four subtypes of receptors which have been classified as EP1-4. Fish oil is a source of omega-3 fatty acids (OM-3FAs) which may be effective in prevention of ovarian cancer. Our objective was to assess the potential impact of fish oil on expression of COX enzymes, PGE2 concentration, apoptosis and proliferation in ovaries of laying hens. METHODS: 48 white Leghorn hens were fed 50, 100, 175, 375 and 700 mg/kg fish oil for 21 days. The OM3-FAs and omega-6 fatty acids contents of egg yolks were determined by Gas Chromatography. Proliferation, apoptosis, COX-1, COX-2 and prostaglandin receptor subtype 4 (EP4) protein and mRNA expression and PGE2 concentration in ovaries were measured by PCNA, TUNEL, Western blot, quantitative real-time qPCR and ELISA, respectively. RESULTS: Consumption of fish oil increased the incorporation of OM-3FAs into yolks and decreased both COX-1 and COX-2 protein and mRNA expression. In correlation with COXs down-regulation, fish oil significantly reduced the concentrations of PGE2 in ovaries. EP4 protein and mRNA expression in ovaries of hens was not affected by fish oil treatment. A lower dose of fish oil increased the egg laying frequency. 175 and 700 mg/kg fish oil reduced proliferation and 700 mg/kg increased apoptosis in hen ovaries. CONCLUSIONS: Our findings suggest that the lower doses of fish oil reduce inflammatory PG and may be an effective approach in preventing ovarian carcinogenesis. These findings may provide the basis for clinical trials utilizing fish oil as a dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.

Effects of food availability on yolk androgen deposition in the black-legged kittiwake (Rissa tridactyla), a seabird with facultative brood reduction.

In birds with facultative brood reduction, survival of the junior chick is thought to be regulated primarily by food availability. In black-legged kittiwakes (Rissa tridactyla) where parents and chicks are provided with unlimited access to supplemental food during the breeding season, brood reduction still occurs and varies interannually. Survival of the junior chick is therefore affected by factors in addition to the amount of food directly available to them. Maternally deposited yolk androgens affect competitive dynamics within a brood, and may be one of the mechanisms by which mothers mediate brood reduction in response to a suite of environmental and physiological cues. The goal of this study was to determine whether food supplementation during the pre-lay period affected patterns of yolk androgen deposition in free-living kittiwakes in two years (2003 and 2004) that varied in natural food availability. Chick survival was measured concurrently in other nests where eggs were not collected. In both years, supplemental feeding increased female investment in eggs by increasing egg mass. First-laid ("A") eggs were heavier but contained less testosterone and androstenedione than second-laid ("B") eggs across years and treatments. Yolk testosterone was higher in 2003 (the year with higher B chick survival) across treatments. The difference in yolk testosterone levels between eggs within a clutch varied among years and treatments such that it was relatively small when B chick experienced the lowest and the highest survival probabilities, and increased with intermediate B chick survival probabilities. The magnitude of testosterone asymmetry in a clutch may allow females to optimize fitness by either predisposing a brood for reduction or facilitating survival of younger chicks.

Screening for microbial metabolites affecting phenotype of Caenorhabditis elegans.

Microbial samples, including our library of known microbial compounds (ca. 300) and microbial culture broths (ca. 9000), were screened for small molecules affecting the phenotype of Caenorhabditis elegans. As a result, seven known compounds were found to induce phenotypic abnormality of C. elegans. Staurosporine exhibited morphological defects in the vulva and tail of C. elegans, avermectin B1a exhibited hatching inhibition of starting eggs on day 1 at 25-100 µM and growth inhibition at 0.01-12.5 µM, siccanin and antimycin A inhibited the growth of C. elegans, and fluorouracil inhibited hatching of eggs newly spawned by adult C. elegans. Toromycin induced morphological defects in the intestine. 5-(4-Methoxyphenyl)-oxazole, isolated as a fungal metabolite for the first time, inhibited the hatching of eggs newly spawned by adult C. elegans.

Ontogenetic expression of maternal and zygotic genes in Atlantic cod embryos under ambient and thermally stressed conditions.

The embryonic stages of Atlantic cod (Gadus morhua) are especially sensitive to incubation temperature. The purpose of the present study was to follow the ontogenetic expression of selected genes of maternal (pou2 and nanog) and zygotic origin (hsp70, hsp90α and stip1), in Atlantic cod embryos under ambient and thermally stressed conditions. The study also investigated how reference genes can be applied to studies on embryonic development, when maternal genes are degraded and the zygotic transcription stabilizes. Three batches of eggs were reared and gene expression profiles from the reference and target genes were determined. The embryos were reared at ambient 6 °C, and 10 °C for continuous long-term and acute short-term heat exposure. Both pou2 and nanog showed reduced expression whereas the zygotic and reference genes showed increased expression until stabilizing at gastrulation, when a normalized ontogenetic expression profile of target genes could be generated. pou2 and nanog were not affected by thermal stress. In contrast, hsp70 and hsp90α were upregulated after short-term heat exposure at the early blastula (hsp70 only), late blastula, 50% epiboly and 90% epiboly stages (hsp90α only). Long-term heat exposure of Atlantic cod embryos upregulated both hsp70 (90% epiboly) and hsp90α (90% epiboly and 20-somites). The results suggest that a cellular defense mechanism is activated even in the earliest stages of embryonic development, a period critical to developmental temperature.

Effects of in ovo injection of L-carnitine on hatchability and subsequent broiler performance and slaughter yield.

Effects of in ovo injection of L-carnitine on the hatchability, grow-out performance, and slaughter yield of Ross x Ross 308 broilers from a young breeder flock were determined through 48 d of age. Fertilized eggs were injected in the amnion with L-carnitine (0.5, 2.0, or 8.0 mg dissolved in 100 microL of a commercial diluent) on d 18 of incubation using an automated egg injector. Three control groups (noninjected and injected with or without diluent) were also included. Hatchability and hatch rate of fertilized eggs were assessed. Furthermore, subsequent mortality, BW gain, feed intake per bird, and feed conversion were determined through 46 d posthatch. On d 47, live body, carcass, and abdominal fat pad weights, along with the weights of all major commercial cuts including the thigh, drumstick, wings, and breast muscles, were determined. Individual doses of supplemental L-carnitine had no significant effect on the hatchability or rate of hatch of fertilized eggs; however, significant trends were noted for increased hatchability and length of egg incubation in conjunction with increases in L-carnitine dose. Nevertheless, there were no significant treatment effects on any of the grow-out performance or slaughter yield parameters investigated. In conclusion, although increasing the levels of L-carnitine added to commercial vaccine diluent between 0.5 and 8.0 mg/100 microL for commercial in ovo injection did not significantly influence subsequent broiler grow-out performance or slaughter yield, L-carnitine dosages above those used in this study have the potential for significantly increasing incubation length and hatchability of broiler hatching eggs.

Strong post-pollination pre-zygotic isolation between sympatric, food-deceptive Mediterranean orchids.

Mediterranean orchids that grow in admixed, co-flowering populations, and frequently show hybrid progenies are interesting to use to study the nature and the strength of post-zygotic barriers. However, examination of pre- and post-pollination pre-zygotic isolating mechanisms requires sympatric, co-flowering species pairs that do not produce hybrid swarms. In this study, we analyzed a contact zone between Orchis italica and O. papilionacea, in which hybrid forms have never been reported, although hybridization between members of their groups of appurtenance has been signaled. We investigated pre-pollination barriers observing the floral phenology of both species and identified pollinators by means of molecular analysis of pollinaria collected on the insects captured in the study site. Post-pollination barriers were tested performing manual crosses in order to evaluate pollen germination/pollen tube growth in vivo and fruit and seed formation. Floral phenologies of O. italica and O. papilionacea display nearly overlapping trends, and two common pollinators have been identified by molecular analysis of pollinaria. Thus, pre-pollination barriers are very weak or nonexistent. Bidirectional crosses have shown that the growth of heterospecific pollen tubes is fully blocked in stigmatic cell layers. Since no fruit formation was detected in bidirectional interspecific crosses, we assume that reproductive isolation between the examined species is fully guaranteed by post-pollination pre-zygotic mechanisms acting at stigmatic level. Such condition has been rarely described and may mask the potential action of post-zygotic mechanisms.

Systematic analysis of embryonic expression profiles of zinc finger genes in Ciona intestinalis.

The recent decoding of a number of animal genomes has provided unprecedented information regarding evolution and gene structures, but this information must be supplemented with precise gene annotations and the temporal and spatial expression patterns of individual genes. In the present study, we systematically identified and characterized 566 zinc finger genes in the genome of Ciona intestinalis, an emerging model system for genome-wide studies of development and evolution. Of these genes, 356 genes encoded a potential transcription factor based on putative nucleic acid binding activity or domains of unknown function. We further examined the expression patterns of 225 genes during embryogenesis, and, when considered with a previous study [Imai, K.S., Hino, K., Yagi, K., Satoh, N., Satou, Y., 2004. Gene expression profiles of transcription factors and signaling molecules in the ascidian embryo: towards a comprehensive understanding of gene networks. Development 131, 4047-4058], we have characterized the developmental expression patterns of nearly 85% of the potential zinc finger-containing transcription factors. Overall, zinc finger genes are preferentially maternally expressed with little larval expression during development. The present study provides a valuable reference for genome-wide studies in this species and for future studies wishing to examine zinc finger gene expression patterns in other animals.

Characterization of triacylglycerols from overwintering prepupae of the alfalfa pollinator Megachile rotundata (Hymenoptera: Megachilidae).

Alfalfa leafcutting bees, Megachile rotundata (F.), overwinter as prepupae. The internal lipids were extracted from prepupae that had been wintered at 4 degrees C for 7 months. Megachile rotundata prepupae possessed copious quantities of internal lipids (20% of the fresh weight) that were extracted with CHCl3/methanol (2:1). Transmission electron microscopy revealed that lipids were stored within very large intracellular vacuoles. Separation by silica chromatography revealed that 88% of the internal lipids were triacylglycerols. Ester derivatives of fatty acids from triacylglycerol components were analyzed by gas chromatography-mass spectrometry and 15 fatty acid constituents were identified. The majority (76%) of the triacylglycerol fatty acids were unsaturated fatty acids. The major triacylglycerol fatty acid constituent (30%) was the C16 monounsaturated fatty acid, palmitoleic acid (16:1, hexadec-9-enoic acid), with substantial amounts of linolenic acid (18:3, octadec-9,12,15-trienoic acid, 15%), palmitic acid (16:0, hexadecanoic acid, 14%) and oleic acid (18:1, octadec-9-enoic acid, 13%). Palmitoleic acid as the major fatty acid of an insect is an unusual occurrence as well as the presence of the 16-carbon polyunsaturated fatty acids, 16:2 and 16:3. The major intact triacylglycerol components were separated and identified by high performance liquid chromatography-mass spectrometry. A complex mixture of approximately 40 triacylglycerol components were identified and major components included palmitoyl palmitoleoyl oleoyl glycerol, palmitoyl palmitoleoyl palmitoleoyl glycerol, myristoyl palmitoleoyl palmitoleoyl glycerol, myristoleoyl palmitoyl palmitoleoyl glycerol, and palmitoyl palmitoleoyl linolenoyl glycerol. The function of these internal lipids and their relevance to winter survival and post-wintering development of M. rotundata is discussed.

Plasmodium berghei ookinetes induce nitric oxide production in Anopheles pseudopunctipennis midguts cultured in vitro.

The Anopheles pseudopunctipennis nitric oxide synthase gene (ApNOS) was identified and its partial sequence showed high homology with NOS from A. stephensi, A. gambiae (putative sequence), and Drosophila melanogaster. ApNOS was mainly expressed in male and female adult mosquitoes and was induced by a blood meal. Nitric oxide (NO) was produced by in vitro-cultured mosquito midguts inoculated by enema with Plasmodium berghei ookinetes, Saccharomyces cerevisiae, Gram-positive bacteria (Micrococcus luteus), but not with Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli or Serratia marcescens). Dihydroxyphenylalanine (L-DOPA) oxidation induced the generation of NO in midguts in vitro, and hydrogen peroxide generated during its oxidation induced ApNOS expression. P. berghei ookinetes exposed in vitro to L-DOPA and sodium nitroprusside (a NO generator) were killed. These observations demonstrate that reactive oxygen and nitrogen intermediates constitute a part of the cytotoxic arsenal employed by Anopheles mosquitoes against microbial pathogens and Plasmodium ookinetes.

Genetic influences on prepulse inhibition of startle reflex in humans.

Prepulse inhibition (PPI) is a suppression of the startle reflex that occurs when an intense startling stimulus is preceded by a weaker 'prepulse' stimulus. PPI deficits have been implicated in the biological bases of schizophrenia and some other neuropsychiatric disorders and proposed as a possible biological marker (endophenotype) for genetic studies. However, little is known about the genetic determination of PPI in humans. We examined acoustic eye-blink startle reflex and PPI in 142 young female twins (40 monozygotic and 31 dizygotic pairs) and conducted a biometrical genetic analysis using structural equation modeling. PPI showed significant heritability suggesting that over 50% of PPI variance in this sample can be attributed to genetic factors. Baseline startle magnitude showed higher heritability (about 70%).

Asymmetric segregation of PIE-1 in C. elegans is mediated by two complementary mechanisms that act through separate PIE-1 protein domains.

The CCCH finger protein PIE-1 is a regulator of germ cell fate that segregates with the germ lineage in early embryos. At each asymmetric division, PIE-1 is inherited preferentially by the germline daughter and is excluded from the somatic daughter. We show that this asymmetry is regulated at the protein level by two complementary mechanisms. The first acts before cell division to enrich PIE-1 in the cytoplasm destined for the germline daughter. The second acts after cell division to eliminate any PIE-1 left in the somatic daughter. The latter mechanism depends on PIE-1's first CCCH finger (ZF1), which targets PIE-1 for degradation in somatic blastomeres. ZF1s in two other germline proteins, POS-1 and MEX-1, are also degraded in somatic blastomeres, suggesting that localized degradation also acts on these proteins to exclude them from somatic lineages.

IVF of mouse ova in a simplex optimized medium supplemented with amino acids.

The addition of amino acids to a modified simplex optimized medium (mKSOM) did not increase the percentage of blastocysts that develop from CF1 mouse ova fertilized in vitro. In contrast, the percentage of blastocysts that began to hatch and the number of cells in these blastocysts, particularly in the inner cell mass, was increased. The added amino acids also supported the development of a more organized extracellular matrix in the same blastocysts. The results suggest that zygotes produced in amino acid-supplemented mKSOM have a greater developmental potential, perhaps developing at a faster rate, than zygotes produced in mKSOM. This enhanced developmental potential may be caused by the alleviation of osmotic stress on the ova and zygotes by the amino acids that are osmolytes. The fertilization of human ova in vitro may benefit from the inclusion of free amino acids in the fertilizing medium. The availability of a medium that can be used to support both IVF and preimplantation development in the mouse is likely to benefit the recovery of mouse strains from cryopreserved spermatozoa.

X inactivation: Tsix and Xist as yin and yang.

A new study shows that expression of Tsix, an antisense Xist gene, can be controlled by imprinting, and that high Tsix activity during X inactivation can protect the future active X chromosome from silencing by Xist. Tsix and Xist seem to have a yin and yang relationship, with opposite effects on X inactivation.