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1.
So far, four RNA:pseudouridine (Ψ)-synthases have been identified in yeast Saccharomyces cerevisiae. Together, they act on cytoplasmic and mitochondrial tRNAs, U2 snRNA and rRNAs from cytoplasmic ribosomes. However, RNA:Ψ-synthases responsible for several U→Ψ conversions in tRNAs and UsnRNAs remained to be identified. Based on conserved amino-acid motifs in already characterised RNA:Ψ-synthases, four additional open reading frames (ORFs) encoding putative RNA:Ψ-synthases were identified in S.cerevisiae. Upon disruption of one of them, the YLR165c ORF, we found that the unique Ψ residue normally present in the fully matured mitochondrial rRNAs (Ψ2819 in 21S rRNA) was missing, while Ψ residues at all the tested pseudouridylation sites in cytoplasmic and mitochondrial tRNAs and in nuclear UsnRNAs were retained. The selective U→Ψ conversion at position 2819 in mitochondrial 21S rRNA was restored when the deleted yeast strain was transformed by a plasmid expressing the wild-type YLR165c ORF. Complementation was lost after point mutation (D71→A) in the postulated active site of the YLR165c-encoded protein, indicating the direct role of the YLR165c protein in Ψ2819 synthesis in mitochondrial 21S rRNA. Hence, for nomenclature homogeneity the YLR165c ORF was renamed PUS5 and the corresponding RNA:Ψ-synthase Pus5p. As already noticed for other mitochondrial RNA modification enzymes, no canonical mitochondrial targeting signal was identified in Pus5p. Our results also show that Ψ2819 in mitochondrial 21S rRNA is not essential for cell viability.  相似文献   

2.
《Journal of Asia》2020,23(4):1279-1282
The behavior and effective predation time can affect the prey death in pest biological control programs. This work studied the Podisus nigrispinus (Dallas, 1851) (Heteroptera: Pentatomidae) behavior on Spodoptera eridania (Cramer, 1782) (Lepidoptera: Noctuidae) caterpillars, and its implications in case of prey escape. The preference bioassay (B1) aimed to verify the caterpillars body region (anterior: head and thorax; median and posterior) preferred by the predator and its implication in prey mortality. The predation duration bioassay considered the following effective predation times: 1, 2, 4, 8, 16, 32, 64 and 128 min; the caterpillars were removed after each predation time, to simulate prey escape, and the dead were counted until the seventh day. This experiment was performed in two ways: with randomly selected and not repeated predators (B2); and with the same predators in successive times (B3). The predator preferred to attack the caterpillars anterior region. The caterpillars mortality increased with increasing effective predation time. The mortality was 90% after 64 min under B2. This value was estimated for 16 min under B3. The P. nigrispinus prefers to attack the caterpillars anterior region and mortality of S. eridania caterpillars was favored in predators that have suffered predation interruption.  相似文献   

3.
《Gene》1997,195(2):217-227
Bacteriophage SfV is a temperate phage of Shigella flexneri responsible for converting serotype Y (3,4) to serotype 5a (V; 3,4) through its glucosyl transferase gene. The glucosyl transferase (gtr) gene of SfV has been cloned and shown to partially convert S. flexneri serotype Y to serotype 5a. In this study, we found that the serotype-converting region of SfV was approximately 2.5 kb in length containing three continuous ORFs. The recombinant strain carrying the three complete ORFs expressed the type V and group antigen 3,4, both indistinguishable from that of S. flexneri 5a wild-type strain. The interruption of orf5 or orf6 gave partial conversion in the S. flexneri recombinant strain indicated by the incomplete replacement of group antigen 3,4. The region adjacent to the serotype-conversion genes was found to be identical to the attP-int-xis region of phage P22. Altogether, an approximately 2.2-kb sequence covering a portion of the serotype-conversion (approximately 500 nt)-attP-int-xis regions of SfV was remarkably similar to that of P22.  相似文献   

4.
A comparative study of Spodoptera nuclear polyhedrosis virus (NPV) and Autographa NPV replication in Spodoptera exigua revealed some cytopathologic differences. Infection with Spodoptera NPV was accompanied by electron-dense intranuclear granules. Autographa infection within the midgut led to secretion within the lumens of the goblet cells of paracrystalline arrays of small, round particles, 9.5 nm in diameter. Autographa virus was also observed in various stages of possible replication within the cytoplasm.  相似文献   

5.
6.
A new Isospora species is described from New Holland honeyeaters (Phylidonyris novaehollandiae). Sporulated oocysts (n = 25) were characterised as subspheroidal, 29–32 × 28–31 (29.8 × 29.4); length/width (L/W) ratio 1.01–1.02 (1.01). Wall bi-layered, 1.3–1.6 (1.5) thick, outer layer smooth, c.2/3 of total thickness. Micropyle and oocyst residuum absent, but usually two polar granules are present. Sporocysts (n = 25) ovoidal, 18–19 × 12–14 (18.4 × 12.3); L/W ratio 1.42–1.53 (1.50). Stieda body present, flattened, c.0.5 deep × 2.5 wide; sub-Stieda present, rounded, c.2.5 deep × 3.5 wide; para-Stieda body absent; sporocyst residuum present, usually a distinctly irregular body consisting of numerous small granules that appear to be membrane-bound. Sporozoites vermiform, with robust anterior and posterior refractile bodies. Molecular characterization was conducted at the 18S and 28S ribosomal RNA and the mitochondrial (mt) cytochrome oxidase (COI) loci. Phylogenetic analysis of genomic 18S and mt COI sequences indicated that Isospora phylidonyrisae n. sp. was genetically similar to Isospora coronoideae, isolated from an Australian raven (Corvus coronoides) in Western Australia, with a 99.3% and 98.4% homology, respectively. The 28S rRNA sequence was most similar to Isospora anthochaerae (KF766053) and Isospora manorinae (KT224381), both with a 98.2% genetic similarity. Based on morphological and genetic data, this isolate is a new species of Isospora, which is named Isospora phylidonyrisae n. sp. after its host.  相似文献   

7.
Vascular endothelial growth factors165 (VEGF165) is the most potent and widely used pro-angiogenic factor. Here we determined optimal culture condition of recombinant human VEGF165 (rhVEGF165) in Escherichia coli (E. coli). rhVEGF165 expression was the highest in 0.25% of l-arabinose induction concentration, at 20 °C induction temperature, and for 5 h induction time under the control of araBAD promoter using pBADHisA vector. In biological activity test, rhVEGF165 significantly increased the proliferative activity of CPAE cells (p < 0.001) and upregulated the expressions of endothelial cell growth-related genes, such as platelet endothelial cell adhesion molecule (PECAM-1), endothelial-specific receptor tyrosine kinase (TEK), kinase insert domain protein receptor (KDR), and tyrosine kinase with immunoglobulin-like and EGF-like domains 1 (TIE1) in calf pulmonary artery endothelial (CPAE) cells.  相似文献   

8.
Clitostethus arcuatus is a major, cosmopolitan predator of some Aleyrodidae. Field collected adult beetles were reared in the laboratory on different diets: Siphoninus phillyreae eggs, Trialeurodes vaporariorum eggs, Sitotroga cerealella eggs, or an artificial diet consisting of honey, yeast, and pollen. All experiments were conducted at 25 ± 2 °C, 65 ± 5% RH and a photoperiod of 16:8 (L:D) h. Female and male C. arcuatus consumed a mean (± SE) of 61 ± 0.6 and 27 ± 0.9 T. vaporariorum eggs d? 1, respectively, and a mean of 56 ± 2.2 and 29 ± 1.1 S. phillyreae eggs d? 1, respectively. Significant differences were noted between sexes and between hosts consumed by female C. arcuatus. No feeding occurred on S. cerealella eggs. Although there was a significant difference between rates of oviposition due to diet, fertility rates on different diets did not show significant differences. The sex ratio of C. arcuatus (female:male) was 51.4:48.6, 55.2:44.8, and 54.6:45:4 when adults fed on T. vaporariorum, S. phillyreae, and artificial diet, respectively. These differences were not significantly different. Average longevity (± SE) was 66.4 ± 2.6, 54.9 ± 2.5; 77.3 ± 6.9, 67.5 ± 7.2; and 86.4 ± 4.5 70.3 ± 3.6 days for female and male C. arctuatus, respectively, on T. vaporariorum, S. phillyreae and artificial diet, respectively, with significant differences between sexes and diets. Although developmental duration on T. vaporariorum was longer than ash whitefly, this difference was not significant (mean 27.68 ± 0.31 and 25.09 ± 0.21 days for predators reared on T. vaporariorum and S. phillyreae, respectively). Given its longevity and fecundity on T. vaporariorum, C. arcuatus may be a good choice for mass release on glasshouse crops infected by greenhouse whitefly.  相似文献   

9.
A pathogen inactivation (PI) process has been developed using the frangible anchor linker effector (FRALE) compound S-303. A series of experiments were performed in whole blood (WB) to measure the level of viral and bacterial inactivation. The results showed that 0.2 mM S-303 and 2 mM glutathione (GSH) inactivated >6.5 logs of HIV, >5.7 logs of Bluetongue virus, >7.0 logs of Yersinia enterocolitica, 4.2 logs of Serratia marcescens, and 7.5 logs of Staphylococcus epidermidis. Recent development for S-303 is focused on optimization of the PI process for red blood cell concentrates (RBC). A series of studies in RBC showed that 0.2 mM S-303 and 20 mM GSH inactivated approximately 5 logs or greater of Y. enterocolitica, E. coli, S. marcescens, S. aureus, HIV, bovine viral diarrhoea virus, bluetongue virus and human adenovirus 5. In both applications of the S-303 process, in vitro parameters of RBC function and physiology were retained compared to conventional RBC. Results from these studies indicate that S-303 can be applicable for PI of RBC and WB.  相似文献   

10.
A new Eimeria Schneider, 1875 species is described from an Australian pelican Pelecanus conspicillatus Temminck, 1824 in Western Australia. Sporulated oocysts (n = 23) subspheroidal, 33–35 × 31–33 (34.1 × 32.0) μm; length/width (L/W) ratio 1.0–1.1 (1.07). Wall bi-layered, 1.2–1.5 (1.4) μm thick, outer layer smooth, c.2/3 of total thickness. Micropyle absent, but 2 or 3 polar granules surrounded by a thin membrane, apparently residual, are present. Sporocysts (n = 23) elongate ellipsoidal or capsule shaped, 19–20 × 5–6 (19.5 × 5.6) μm; L/W ratio 3.4–3.8 (3.51). Stieda body vestigial and barely discernible, 0.5 × 1.0 μm; sub-Stieda and para-Stieda bodies absent; sporocyst residuum present, composed of a few dense spherules dispersed among the sporozoites. Sporozoites with robust anterior and posterior refractile bodies and centrally located nucleus. Molecular analysis was conducted at three loci; the 18S and 28S ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene. At the 18S locus, the new isolate shared 98.6% genetic similarity with Eimeria fulva Farr, 1953 (KP789172), which was identified from a goose in China. At the 28S locus, the new isolate shared the highest similarity of 96.2% with Eimeria hermani Farr, 1953 (MW775031) identified from a whooper-swan (Cygnus cygnus (Linnaeus, 1758)) in China. At the COI gene locus, this new isolate was most closely related to Isospora sp. isolate COI-178 and Eimeria tiliquae [25,26], presented 96.5% and 96.2% genetic similarity, respectively. Based on the morphological and molecular data, this isolate is a new species of coccidian parasite, which is named Eimeria briceae n. sp.  相似文献   

11.
The accumulation and biosynthesis of cuticular and internal hydrocarbons in the Southern armyworm, Spodoptera eridania, were examined at closely timed intervals during larval and pupal development. Gas chromatography-mass spectrometry (GC-MS) was used to identify n-alkanes, monomethylalkanes, and dimethylalkanes ranging in chain length from 23 to 35 carbons. The amount of cuticular hydrocarbon stayed relatively constant during each stadium, while the amount of internal hydrocarbon increased dramatically during the first half of each larval stadium, presumably to replace the cuticular hydrocarbon lost on the shed cast skin with each molt. The accumulation of internal hydrocarbon was mirrored by large increases in the rate of incorporation of labeled acetate into the hydrocarbon fraction. Hydrocarbon production fell to very low rates during the latter part of the fourth and fifth larval stadia. Relatively high rates of hydrocarbon production were observed during the first and last one-third of the pupal stage and essentially all of the hydrocarbons produced during this stage remained internal. These data document large changes in the rates of hydrocarbon production during development in S. eridania and suggest that most of the hydrocarbon produced during each stage was stored internally and then transported to the cuticle of the next stage.  相似文献   

12.
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14.
《Journal of Asia》2023,26(4):102123
The deformed wing virus (DWV) is one of the most common bee pathogens, deemed responsible for both honey bee colony losses and general pollinator decline. That virus may infect both managed and wild bumblebees. In this study, the DWV infection was investigated in 52 free-flying Bombus terrestris (L., 1758) individuals from Pantelleria. This is a volcanic island in the Sicilian Channel. Of the collected individuals, 59.62% scored positive for DWV, with a mean abundance of 2.97 × 105 ± 1.46 × 106 copies per bee. Active replication of the virus could be demonstrated in all positive samples. All the sequences belonged to DWV type A. However both phylogenetic and pairwise distance analysis indicated a low similarity to Italian and Tunisian strains. Further studies are needed to elucidate the epidemiology of DWV in B. terrestris and the drivers of possible genetic modifications of the virus on Pantelleria island.  相似文献   

15.
A novel victorivirus, termed Rosellinia necatrix victorivirus 1 (RnVV1), was isolated from a plant pathogenic ascomycete, white root rot fungus Rosellinia necatrix, coinfected with a partitivirus. The virus was molecularly and biologically characterized using the natural and experimental hosts (chestnut blight fungus, Cryphonectria parasitica). RnVV1 was shown to have typical molecular victorivirus attributes, including a monopartite double-stranded RNA genome with two open reading frames (ORFs) encoding capsid protein (CP) and RNA-dependent RNA polymerase (RdRp), a UAAUG pentamer presumed to facilitate the coupled termination/reinitiation for translation of the two ORFs, a spherical particle structure ∼40 nm in diameter, and moderate levels of CP and RdRp sequence identity (34 to 58%) to those of members of the genus Victorivirus within the family Totiviridae. A reproducible transfection system with purified RnVV1 virions was developed for the two distinct fungal hosts. Transfection assay with purified RnVV1 virions combined with virus elimination by hyphal tipping showed that the effects of RnVV1 on the phenotype of the natural host were negligible. Interestingly, comparison of the RNA silencing-competent (standard strain EP155) and -defective (Δdcl-2) strains of C. parasitica infected with RnVV1 showed that RNA silencing acted against the virus to repress its replication, which was restored by coinfection with hypovirus or transgenic expression of an RNA silencing suppressor, hypovirus p29. Phenotypic changes were observed in the Δdcl-2 strain but not in EP155. This is the first reported study on the host range expansion of a Totiviridae member that is targeted by RNA silencing.  相似文献   

16.
The binding and pore formation properties of four Bacillus thuringiensis Cry1 toxins were analyzed by using brush border membrane vesicles from Spodoptera exigua and Spodoptera frugiperda, and the results were compared to the results of toxicity bioassays. Cry1Fa was highly toxic and Cry1Ac was nontoxic to S. exigua and S. frugiperda larvae, while Cry1Ca was highly toxic to S. exigua and weakly toxic to S. frugiperda. In contrast, Cry1Bb was active against S. frugiperda but only marginally active against S. exigua. Bioassays performed with iodinated Cry1Bb, Cry1Fa, and Cry1Ca showed that the effects of iodination on toxin activity were different. The toxicities of I-labeled Cry1Bb and Cry1Fa against Spodoptera species were significantly less than the toxicities of the unlabeled toxins, while Cry1Ca retained its insecticidal activity when it was labeled with 125I. Binding assays showed that iodination prevented Cry1Fa from binding to Spodoptera brush border membrane vesicles. 125I-labeled Cry1Ac, Cry1Bb, and Cry1Ca bound with high-affinities to brush border membrane vesicles from S. exigua and S. frugiperda. Competition binding experiments performed with heterologous toxins revealed two major binding sites. Cry1Ac and Cry1Fa have a common binding site, and Cry1Bb, Cry1C, and Cry1Fa have a second common binding site. No obvious relationship between dissociation of bound toxins from brush border membrane vesicles and toxicity was detected. Cry1 toxins were also tested for the ability to alter the permeability of membrane vesicles, as measured by a light scattering assay. Cry1 proteins toxic to Spodoptera larvae permeabilized brush border membrane vesicles, but the extent of permeabilization did not necessarily correlate with in vivo toxicity.  相似文献   

17.
J. Mark Scriber 《Oecologia》1981,51(2):175-180
Summary This study illustrates the diversity of feeding responses of individually polyphagous southern armyworms, Spodoptera eridania, to plants with differing allelochemics. In spite of the near optimal leaf water and nitrogen contents of the young foliage, it is apparent that vastly different larval growth performance results from dill, lima bean, and cabbage. Cabbage is the poorest food (as measured by larval growth rates and metabolic costs of processing the plant biomass). Unlike the case with certain other plant species or cultivars that are costly to process, with cabbage, S. eridania does not compensate for low efficiencies (E.C.D.'s) with increased consumption rates (R.C.R.'s). Biochemical or physiological reasons for this inability are unknown.A sequence of foods (changed each 18–24 h) apparently did not add sufficient stress upon the MFO system to be detected in the respiratory expenditures of S. eridania larvae, in spite of the fact that dill is known to contain insecticidal and synergistic chemicals (Lichtenstein et al. 1974). The larval growth performances and metabolic expenditures in these sequences were intermediate between the best food (dill) and the worse (cabbage). Significant differences were observed however between the sequential switching sequences, perhaps indicating that particular periods during the instar are especially more sensitive to certain allelochemics. Actual respiratory costs of the lima bean-cabbage-dill (i.e. B-C-D) sequence were 40–50% higher than observed for the other two sequences and more than 50% higher than the theoretical metabolic costs based on the proportions actually eaten and known costs associated with each food.This study and a related one (Scriber 1981a) illustrate how consumption rates, feeding efficiences, and larval growth of Spodoptera eridania are not species, population, or even individual characteristics, (cf. Fox and Morrow 1981), but instead depend largely upon variations in plant allelochemics and plant nutritional quality (Wolfson 1978; Scriber, 1981 b; Scriber and Slansky 1981). More significantly they illustrate that the food consumed in earlier instars (Scriber 1981 a) as well as the food consumed earlier in an instar can be a major influence upon the observed armyworm growth performances under a given set of environmental conditions.A publication of the College of Agriculture and Life Sciences, University of Wisconsin, Madison 53706Mention of a product or brand name does not reflect an endorsement of that item by the University of Wisconsin  相似文献   

18.
Larvae of the black swallowtail butterfly, Papilio polyxenes, the southern armyworm, Spodoptera eridania, and the cabbage looper, Trichoplusia ni, have different feeding habits and dietary breadth, which contributes to differences in their exposure and tolerance to dietary prooxidant allelochemicals. The antioxidant enzyme activities of larvae of these insects have been previously determined, with the levels being P. polyxenes > S. eridania > T. ni. The relative activities of these antioxidant enzymes are consistent with the relative exposure of these insects to prooxidants. This suggests that the antioxidant enzymes may play a role in the defense against allelochemical toxicity in these insects. Dietary diethlydithiocarbamate (DETC), a copper chelating agent and superoxide dismutase (SOD) inhibitor, was shown to inhibit SOD in all three insects. Toxicological studies were conducted using four diets for each insect. The standard diets for each insect were supplemented with either control (solvent), quercetin (a prooxidant), DETC, or DETC plus quercetin. Nontoxic doses of each compound for each insect were used. Inhibition of SOD in P. polyxenes and S. eridania dramatically increased quercetin-induced toxicity as measured by relative growth and consumption rates in these species. DETC had no effect on quercetin toxicity in T. ni. These results elucidate the important role of SOD in the prooxidant allelochemical defense of insects.  相似文献   

19.
The genome of fowlpox virus (FWPV), type species of the Avipoxviridae, is considerably rearranged compared with that of vaccinia virus (the prototypic poxvirus and type species of the Orthopoxviridae) and is 30% larger. It is likely that the genome of FWPV contains genes in addition to those found in vaccinia virus, probably involved with its replication and survival in the chicken. A 7,470-bp segment of the FWPV genome has five open reading frames (ORFs), two of which encode ankyrin repeat proteins, many examples of which have been found in poxviruses. The remaining ORFs encode homologs of cellular genes not reported in any other virus. ORF-2 encodes a homolog of the yeast Sec17p and mammalian SNAP proteins, crucial to vesicular transport in the exocytic pathway. ORF-3 encodes a homolog of an orphan human protein, R31240_2, encoded on 19p13.2. ORF-3 is also homologous to three proteins (YLS2, YMV6, and C07B5.5) from the free-living nematode Caenorhabditis elegans and to a 43-kDa antigen from the parasitic nematode Trichinella spiralis. ORF-5 encodes a homolog of the mammalian plasma cell antigen PC-1, a type II glycoprotein with exophosphodiesterase activity. The ORFs are present in the virulent precursor, HP1, of the sequenced attenuated virus (FP9) and are conserved in other strains of FWPV. They were shown, by deletion mutagenesis, to be nonessential to virus replication in tissue culture. RNA encoding the viral homolog of PC-1 is expressed strongly early and late in infection, but RNAs encoding the homologs of SNAP and R31240_2 are expressed weakly and late.  相似文献   

20.
The fungi Nomuraea rileyi and Isaria tenuipes (=Paecilomyces tenuipes) are ecologically obligate, widespread pathogens of lepidopterans. Bioassays were carried out to evaluate the activity of oil-suspended conidia of N. rileyi and I. tenuipes against larvae of Spodoptera frugiperda, Spodoptera exigua, Helicoverpa zea, and Heliothis virescens. The tests consisted of two bioassay sets. In the first set, conidia of N. rileyi and I. tenuipes were suspended in water + Tween 80, and in vegetable (canola, soybean) and mineral (proprietary mixture of alkanes and cyclic paraffins) oils, and tested against S. frugiperda. Both fungi were highly compatible with oils and caused mortalities near 100% in all oil treatments; the lowest LT50 values were 4.7 days for N. rileyi in mineral oil and 6.0 days for I. tenuipes in soybean oil. The second set included additional fungal strains and oil formulations (mineral, canola, sunflower, olive and peanut oils) tested against larvae of S. exigua, S. frugiperda, H. zea and H. virescens. The highest activity was that of N. rileyi in mineral oil against Spodoptera spp., with LT50 values of 2.5 days (strain ARSEF 135) and 3 days (strain ARSEF 762) respectively. For two different isolates of I. tenuipes the lowest LT50 values (5.1-5.6 days respectively) were obtained with mineral oil formulations against Spodoptera spp. and H. zea respectively. Additionally, we tested both fungi against prepupae of all four lepidopteran species. Mortalities with I. tenuipes against S. exigua ranged from 90% to 100% (strains ARSEF 2488 and 4096); N. rileyi caused 95% mortality on S. frugiperda. The activity of formulations depended on host species and oil used; Spodoptera spp. was more susceptible to these fungi than Heliothis and Helicoverpa. The results indicate that a comprehensive evaluation of these entomopathogens in agriculture using oil application technologies is advisable, particularly, in organic and sustainable settings.  相似文献   

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