Sperm competition and the significance of female multiple mating in the predatory miteParasitus fimetorum

Females of the predatory miteParasitus fimetorum (Gamasida; Parasitina) inhabiting animal manure indiscriminately copulate with many mates. The sperm competition between the males was estimated by electrophoresis of allozymes and the effects of multiple mating on female reproduction were investigated. When females were forced to mate only once, their fecundity decreased drastically compared to the case of multiple mating (but longevity was unaffected). When one female mated with two males, the outcome of sperm competition depended greatly upon the mating interval. When the second mating occurred immediately after the first, the female fecundity decreased as in the case of single mating and the second male fertilized only a few eggs. However, when there was an interval of 1 day between the two matings, the females achieved normal fecundity and the second male fertilized approximately half the eggs. This suggests that the spermatophore deposited by the first male may act as a short-term copulatory ‘plug’ in the female's genital opening. When one female mated with several males with 1 day intervals, three or more males shared fertilization of the eggs. This study suggests that the multiple mating of females is a necessary stimulus to continue oogenesis and some physiological factors for this stimulation may exist in spermatophores.     

Ubiquinone systems of the genus Cladosporium and morphologically similar taxa

Abstract We measured adenosine deaminase (ADA) activity in a guinea pig model of Legionella pneumophila infection. Female Hartley guinea pigs were inoculated intraperitoneally with one-quarter of the LD₅₀ dose of L. pneumophila Philadelphia-1 strain. Control groups were inoculated with clinical isolates of Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae or Klebsiella pneumoniae . Each group consisted of 5 animals. ADA activity in plasma was assayed calorimetrically before and at various intervals after infection by measuring the amount of ammonia produced after adnosine was added to plasma samples. ADA activity before inoculation was 25.6±6.0 IU/1, it reached 174.4±60.0 IU/1 on day 3 after inoculation of L. pneumophila . ADA activity returned to normal levels on day 14. ADA activity did not increase significantly in guinea pigs infected with the other types of bacteria. These findings suggest that measurement of plasma ADA activity may be useful for the diagnosis of Legionella infection.     

Pluripotency of mouse embryonic cells on germline at 3.5–8.5 and 11.5 days post-coitum after aggregation with precompacted embryos

Albino mouse embryonic cells (Gpi-la/a) at 3.5–8.5 and 11.5 days were aggregated with zona cut 8–16 cell stage embryos from F₁ females (Gpi-1 b/b), respectively. The aggregated embryos were transferred to pseudopregnant female mice. The recipients were allowed to go to term or were dissected at mid-gestation to assess the donor contribution in the conceptuses using glucose phosphate isomerase (GPI) analysis. The donor cells, which were previously labeled with fluorescent latex microparticles, were aggregated with embryos, and the allocation of the donor cells at the compacted morula and blastocyst stages were observed under a fluorescence microscope. When 3.5 and 45 day old inner-cell-mass (ICM) cells were used, fertile chimeric mice were obtained (50 and 19%, respectively), and when 5.5 days old primitive ectoderm cells were aggregated, they did not form chimeras but contributed to the fetuses, placenta and membrane after 13.5 days of pregnancy. However, cells from further stages never contributed to the conceptuses even though they were analyzed after 10.5 days of pregnancy. The labeled donor cells at these stages were not positively incorporated in the interior part of the compacted morula and the ICM of the blastocyst stage unlike the ICM at 3.5 days post-coitum after overnight culture.     

Developmental Expression of D-Galactoside-Binding Lectin in Sea Urchin (Anthocidaris crassispina) Eggs

The spatial and temporal expression of a sea urchin (Anthocidaris crassispina) egg lectin (SUEL) during early embryogenesis was studied using antiserum raised against SUEL. Western blotting analysis revealed the presence of SUEL in all stages so far examined, from unfertilized eggs to gastrula stage embryos. Immunofluorescence and immunoelectron microscopic observation showed that SUEL was stored in small electron-dense granules which migrated to the cortex within 10 min after fertilization. SUEL was localized in the cortical cytoplasm of the blastomere during cleavage stages and subsequently migrated to the outer surface of the embryo, including the invaginated portion of the gastrula. Immunoelectron microscopic study indicated that SUEL was deposited in the hyaline layer at least at the mid gastrula stage. Migration of SUEL to the cortex was significantly reduced by treatment with cytochalasin B, suggesting that actin filaments play an important role in this translocation. Exogenously added SUEL was adsorbed at the surface of unfertilized eggs and hatched embryos, but not to embryos with fertilization membrane. Lactose inhibited this adsorption, suggesting the presence of an endogenous glycoligand(s) specific for SUEL on the surface of unfertilized eggs and in the hyaline layer. We conclude that SUEL is secreted at a certain stage of embryogenesis and specifically adsorbed to the hyaline layer. Temporal changes in extraembryonic matrices caused by SUEL seem to play an important role in developmental morphogenesis.     

Molecular cloning and functional characterization of a cDNA encoding nucleosome assembly protein 1 (NAP-1) from soybean

NAP-1, a protein first isolated from mammalian cells, can introduce supercoils into relaxed circular DNA in the presence of purified core histones. Based on its in vitro activity, it has been suggested that NAP-1 may be involved in nucleosome assembly in vivo. We isolated a cDNA clone encoding a soybean NAP-1 homolog, SNAP-1. The SNAP-1 cDNA contains an open reading frame of 358 amino acid residues with a calculated molecular weight of 41 kDa. The deduced amino acid sequence of SNAP-1 shares sequence similarity with yeast NAP-1 (38%) and human hNRP (32%). Notable features of the deduced sequence are two extended acidic regions thought to be involved in histone binding. SNAP-1 expressed in Escherichia coli induces supercoiling in relaxed circular DNA, suggesting that SNAP-1 may have nucleosome assembly activity. The specific activity of SNAP-1 is comparable to that of HeLa NAP-1 in an in vitro assay. Western analysis reveals that SNAP-1 is expressed in the immature and young tissues that were examined, while mature tissues such as old leaves and roots, show very little or no expression. NAP-1 homologs also appear to be present in other plant species.     

Oviposition deterrents from the egg masses of the adzuki bean borer, Ostrinia scapulalis and Asian corn borer, O. furnacalis

Bioassays using gravid females of the adzuki bean borer, Ostrinia scapulalis (Walker), and the Asian corn borer, O. furnacalis (Guenée) (Lepidoptera: Crambidae), showed that the presence of an egg mass of a conspecific deters oviposition. Volatile chemicals emanating from the egg mass were responsible for the deterrence, and these deterrents could be extracted from the egg mass with hexane. When fractionated using a Sep‐Pak® Plus NH₂ cartridge, the deterrents were eluted with a 98 : 2 mixture of diethyl ether and acetic acid (polar lipid fraction). The polar lipid fraction contained free fatty acids with 14–20 carbons, and palmitic acid, palmitoleic acid, and oleic acid were predominant. A blend of all identified fatty acids, a blend of six major fatty acids (palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids), a blend of the two Z‐9‐alkenoic acids (palmitoleic and oleic acids), palmitoleic acid alone, and oleic acid alone showed deterrence against O. scapulalis which was comparable to that provoked by the full egg extract. The dose‐dependency of the deterrent effects of palmitoleic acid and oleic acid was verified in O. scapulalis. The binary blend of palmitoleic acid and oleic acid was also confirmed to deter oviposition in O. furnacalis.     

Induction of a specific isoenzyme of glutamate dehydrogenase during isolation and the first 48 h of culture of Brassica napus leaf protoplasts

The specific activity of NADH‐glutamate dehydrogenase (GDH, EC 1.4.1.2) in leaf protoplasts ( Brassica napus L. cv. Bronowski) was initially low and progressively increased during culture in Murashige and Skoog (MS) medium and MS (−NH₄) (ammonium nitrate‐free MS) medium in the dark. Native polyacrylamide gel electrophoresis (PAGE) and tetrazolium staining revealed that the high specific activity of NAD‐GDH (deamination) in leaves correlated with the cathodal isoenzymes, and the high specific activity of NADH‐GDH (amination) in leaf protoplasts to the anodal ones. Changes in isoenzyme pattern were correlated with an increase in the specific activity of NADH‐GDH but not with the NADH‐GDH/NAD‐GDH ratio. The increase in NADH‐GDH (amination) activity of leaf protoplasts was correlated with the occurrence of the isoenzyme GDH7, which was not detected in leaves.     

Physical mapping of unique nucleotide sequences on identified rice chromosomes

A physical mapping method for unique nucleotide sequences on specific chromosomal regions was developed combining objective chromosome identification and highly sensitive fluorescence in situ hybridisation (FISH). Four unique nucleotide sequences cloned from rice genomic DNAs, varying in size from 1.3 to 400 kb, were mapped on a rice chromosome map. A yeast artificial chromosome (YAC) clone with a 399 kb insert of rice genomic DNA was localised at the distal end of the long arm of rice chromosome (1q2.1) and a bacterial artificial chromosome (BAC) clone (180 kb) containing the rice leaf blast-resistant gene (Pi-b) was shown to occur at the distal end of the long arm of chromosome 2 (2q2.1). A cosmid (35 kb) with the resistance gene (Xa-21) against bacterial leaf blight was mapped on the interstitial region of the long arm on chromosome 11 (11q1.3). Furthermore a single RFLP marker, 1.29 kb in size, was mapped successfully to the distal region of the long arm of rice chromosome 4 (4q2.1). For precise localisation of the nucleotide sequences within the chromosome region, image analyses were effective. The BAC clone was localised to the specific region, 2q2.1:96.16, by image analysis. The result was compared with the known location of the BAC clone on the genetic map and the consistency was confirmed. The effectiveness and reliability in physically mapping nucleotide sequences on small plant chromosomes achieved by the FISH method using a variety of probes was unequivocally demonstrated.