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1.
Chromatin from a uninucleate dinoflagellate, Crypthecodinium cohnii, a binucleate dinoflagellate, Peridinium balticum, and a chromophyte, Olisthodiscus luteus, was examined by nuclease digestion and the results were compared to those from vertebrates. Gel analysis of the products of staphylococcal (micrococcal) nuclease digestion revealed a DNA repeat unit of 220(±5) base pairs for O. luteus and 215(±5) for P. balticum. Limit digestion gave a core particle of 140 base pairs, revealing that these longer repeat sizes are due to longer linker regions. No repeating subunit structure was found upon electrophoresis of digests of C. cohnii nuclei. Examination of the DNA fragments produced by DNAse I digestion of nuclei isolated from P. balticum and O. luteus showed the same ladder of ten base multiples as seen in chromatin from other eukaryotes. Examination of the kinetics of digestion by DNAse II of Peridinium chromatin revealed less susceptibility when compared to DNAse I digestions while 70% of Olisthodiscus chromatin and 35% of C. cohnii chromatin was sensitive to DNAse II. These data, taken together with previous results from Euglena, indicate that while algal chromatin is similar to that of higher eukaryotes in regard to DNAse I and II action, it differs in that the linker DNA is longer. In addition, the Hl-like histone from O. luteus and P. balticum is located in the linker DNA as in higher eukaryotes.  相似文献   

2.
The effects of intraguild interactions between Dicyphus hesperus Knight (Hemiptera: Miridae) and Paecilomyces fumosoroseus Apopka-97 (PFR-97TM) (Wize) Brown and Smith (Ascomycota: Hypocreales) on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) populations were investigated in tomato greenhouse microcosms. Conditions were established in which interference or synergy would most likely occur; namely, a high number of available whiteflies were combined with large numbers of both D. hesperus and PFR-97TM. We measured live whitefly density in a factorial repeated measures experiment where plants were provided or withheld releases of D. hesperus and/or applications of PFR-97TM for 6 weeks. Releases of D. hesperus were made at a rate of 10 adults/plant during the first and third week and PFR-97TM suspensions were applied with a backpack sprayer at a rate of 18 × 107, 1.3 × 107 and 1.2 × 107 viable blastospores/ml during the first, third and fourth week, respectively. Results revealed a non-significant interaction effect between D. hesperus and PFR-97TM, indicating that their actions were independent. Individual whitefly reductions of 48% and 35% were achieved by PFR-97TM and D. hesperus, respectively. Collectively, the natural enemies reduced whitefly densities by 62% relative to the controls. The density of D. hesperus adults was unaffected by multiple applications of PFR-97TM. These results suggest that the combination of generalist entomopathogenic fungi and generalist predators has the potential to cause increased pest mortality despite evidence of minimal interference.  相似文献   

3.
Larval parasitoids of Yponomeuta malinellus Zell. (Lepidoptera: Yponomeutidae), the apple ermine moth (AEM), were sought in northeast Asia with the goal of identifying potential biological controls of the moth, which appeared to threaten the apple industry in Washington State, USA during the 1980s. Ten primary and four secondary parasitoids were found. Dolichogenidea delecta (Haliday) (Braconidae), Ageniaspis fuscicollis (Dalman) (Encyrtidae), Herpestomus brunnicornis Grav. (Icheumonidae), Bessa paralella (Meigen), and Zenillia dolosa (Meigen) (Tachinidae) were the most important parasitoids. The composition of parasitoid species was more diverse in Korea and Japan than in China; two species were found in China, compared to nine in Korea and seven in Japan. A. fuscicollis caused a greater mortality in all investigated countries; 22.7, 11.0, and 9.3% in China, Korea, and Japan, respectively. There was a high similarity in the composition of the parasitoid complex between Korean and Honshu populations but the rates of parasitization were different. The polyphagous B paralella caused significantly higher parasitism in Honshu (18.2%) than in Korea (0.5%). In contrast, H. brunnicornis caused significantly higher parasitism in Korea (8.7%) than in Japan (2.4%). A. fuscicollis and H. brunnicornis, judged to be the most appropriate parasitoids for biological control of AEM moth in the USA, were collected and sent to the USA for release. A. fuscicollis established and is contributing to the control of AEM.  相似文献   

4.
The importance of epibiosis in Antarctic benthic communities is highlighted here considering the specific diversity of sponges living on shells of the scallop Adamussium colbecki and on spines of the cidaroid urchin Ctenocidaris perrieri. Scallops are from three different areas along the Victoria Land [Tethys Bay (TB), New Harbour (NH), Dunlop Island (DI)], while cidaroid urchins are from NH but not present in the two other stations. Homaxinella balfourensis is the commonest species both on the scallops and cidaroid urchins. Other common species on scallops are Myxilla (Myxilla) asigmata, Lissodendoryx (Ectyodoryx) nobilis and Iophon unicorne at NH, Iophon unicorne at DI, and Iophon radiatum, Haliclona sp. 1, Iophon unicorne and Lissodendoryx (Ectyodoryx) nobilis at TB. The highest number of sponge species we found on a single scallop was ten and the sample was collected at NH. On the spines of C. perrieri, Isodictya erinacea, Iophon unicorne and Haliclona (Rhizoniera) dancoi are present too. A. colbecki and C. perrieri, generally living on soft bottoms, represent important substrata for several sponge species. In this way, sponges may increase their dispersal exploiting valves and spines as stepping stones.  相似文献   

5.
The vegetation of the aquatic and marshland habitats of the Orava region (north of Slovakia) was studied in 2009, using traditional phytosociological methods. Sixteen aquatic and eighteen marsh plant communities were described within 96 phytosociological relevés by using TWINSPAN with the application of the dominance principle. Three associations, Potametum alpini, Potametum zizii and Ranunculo-Juncetum bulbosi, were found as new communities for Slovakia. Myriophylletum verticillati, Potametum nodosi, Potametum graminei and Alisma gramineum community were recorded in the northernmost localities in Slovakia. Among marsh communities, Calletum palustris is very rare, both in the Orava region and in Slovakia as a whole. According to Ellenberg’s indicator values (EIV), moisture was evaluated as the main ecological gradient. Plant communities are ordered along the first Detrended Correspodence Analysis (DCA) axis in a typical hydroseries (Potametea → Lemnetea → Phragmition communis → Phalaridion arundinaceae, Oenanthion aquaticae and Sparganio-Glycerion → Magnocaricion elatae). The second DCA axis was most correlated with EIV for nutrients. Among the five directly measured ecological characteristics (temperature, pH and conductivity of water, water depth, and substrate type), conductivity of water (0.44, P < 0.01) and substrate type (0.32, P < 0.05) were the statistically significant variables explaining the variability along the first DCA axis.  相似文献   

6.
Six new polyhydroxysteroidal glycosides, anthenosides S1  –  S6 ( 1  –  6 ), along with a mixture of two previously known related glycosides, 7 and 8 , were isolated from the methanolic extract of the starfish Anthenea sibogae. The structures of 1  –  6 were established by NMR and HR‐ESI‐MS techniques as well as by chemical transformations. All new compounds have a 5α‐cholest‐8(14)‐ene‐3α,6β,7β,16α‐tetrahydroxysteroidal nucleus and differ from majority of starfish glycosides in positions of carbohydrate moieties at C(7) and C(16) ( 1  –  4 , 6 ) or only at C(16) ( 5 ). The 4‐O‐methyl‐β‐d ‐glucopyranose residue ( 2 ) and Δ24‐cholestane side chain ( 3 ) have not been found earlier in the starfish steroidal glycosides. The mixture of 7 and 8 slightly inhibited the proliferation of human breast cancer T‐47D cells and decreased the colony size in the colony formation assay.  相似文献   

7.
The co-evolutionary relationships between mealybug hosts (Hemiptera: Coccoidea) and Encyrtidae (Hymenoptera) appear to be particularly strong, and many successful classical biological control programmes against mealybugs have been carried out using these parasitoids. It is a puzzle, then, that the obscure mealybug, Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae), is considered to be an American species but is not attacked by native parasitoids in the USA, whereas it is controlled in Europe by Acerophagus maculipennis (Mercet) (Encyrtidae) which was described from the Canary Islands (as Pseudophycus maculipennis). An examination of the biogeographical origins of both the Pseudococcus maritimus complex (to which P. viburni clearly belongs) and the genus Acerophagus Smith, coupled with historical trade records, supports the hypothesis that P. viburni and A. maculipennis are co-evolved Neotropical species, and that both were transported from S. America (probably Chile) to Europe via the Canary Islands on host plants such as potato, possibly as early as the sixteenth century. Invasion of P. viburni into the USA (and elsewhere around the world) occurred later, but without A. maculipennis (or other natural enemies). This explains why P. viburni in the USA is not attacked by native North American parasitoids and why A. maculipennis is not known to attack any mealybugs of Palaearctic origin. The hypothesis adds confidence that well conducted classical biocontrol programmes involving these taxa pose a low environmental risk to native, non-target fauna.  相似文献   

8.
Molecular genetic analysis of Altai osmans of the genus Oreoleuciscus from two different parts of the range was carried out. In this study, based on the mitochondrial Co-1 gene sequence, a total of 25 fish specimens belonging to four genera were examined: (1) O. humilis, 2 specimens; O. potanini, 13 specimens; (2) Pseudaspius leptocephalus, 1 specimen; (3) Tribolodon brandtii, T. hakonensis, and T. sachalinensis from the GanBank database, 9 speciens; and (4) Leuciscus waleckii, 1 specimen (used as an outgroup). The p-distances were very low both within and between the species: (1) 0.20 ± 0.03%; (2) 0.40 ± 0.12%; and (1–2) 0.80 ± 0.04%. To visualize the relationships among all of the species examined, the neighbor joining (NJ), maximum parsimony (MP), Bayesian (BA), and maximum likelihood (ML) trees were constructed. The results obtained using these methods were very similar. It was demonstrated that species assignment of the individuals (barcoding) with the help Co-1 gene was effective, despite of very low divergence of the two osman taxa, which was comparable with typical intraspecific values in other animal groups. Taxonomic status of O. potanini and O. humilis requires further investigation with paying attention to low genetic distances between these species along with the lack of material from sympatric parts of the ranges.  相似文献   

9.
Green tea is purported to promote weight loss. Resting metabolic rate (RMR) and the thermic effect of feeding (TEF) are significant components of total daily energy expenditure and are partially determined by the sympathetic nervous system via catecholamine‐mediated stimulation of β‐adrenergic receptors. Epigallocatechin‐3‐gallate (EGCG: the most bioactive catechin in green tea) inhibits catechol‐O‐methyltransferase, an enzyme contributing to the degradation of catecholamines. Accordingly, we hypothesized that short‐term consumption of a commercially available EGCG supplement (Teavigo) augments RMR and TEF. On two separate occasions, seven placebo or seven EGCG capsules (135 mg/capsule) were administered to 16 adults (9 males, 7 females, age 25 ± 2 years, BMI 24.6 ± 1.2 kg/m2 (mean ± s.e.)). Capsules (three/day) were consumed over 48 h; the final capsule was consumed 2 h prior to visiting the laboratory. Energy expenditure (ventilated hood technique) was determined at rest and for 5 h following ingestion of a liquid meal (caloric content: 40% RMR). Contrary to our hypothesis, RMR was not greater (P = 0.10) following consumption of EGCG (6,740 ± 373 kJ/day) compared with placebo (6,971 ± 352). Similarly, the area under the TEF response curve (Δ energy expenditure) was also unaffected by EGCG (246,808 ± 23,748 vs. 243,270 ± 22,177 kJ; P = 0.88). EGCG had no effect on respiratory exchange ratio at rest (P = 0.29) or throughout the TEF measurement (P = 0.56). In summary, together RMR and TEF may account for up to 85% of total daily energy expenditure; we report that short‐term consumption of a commercially available EGCG supplement did not increase RMR or TEF.  相似文献   

10.
The parasitoid complexes of 22 species of the genus Phyllonorycter reared from 20 host plants were studied in the Middle Volga Basin. From a total of 124 host-parasitoid associations analyzed, 88 had been previously unknown. Minotetrastichus frontalis, Sympiesis sericeicornis, Pnigalio soemius, Closterocerus formosus, and S. gordius were the most frequent species. The highest percentage of parasitoids reared was observed in Ph. ulmifoliella (58.6%) and Ph. sylvella (54%), and the lowest one, in Ph. salictella (15%). Ph. corylifoliella (95.7%), Ph. populifoiella (95.5%) and Ph. insignitella (95.5%) had the highest mortality due to parasitoids. The number of endoparasitoid species prevailed over that of ectoparasitoids in the parasitoid complexes of the genus Phyllonorycter, but the number of individuals reared was 4 times greater for ectoparasitoids. The parasitoid complexes were the most similar in Ph. harrisella and Ph. quercifoliella on Quercus robur. The gregarious ectoparasitoid M. frontalis predominated over parasitoids of Phyllonorycter.  相似文献   

11.
We report on the first sightings of the invasive Rapa Whelk Rapana venosa in Maldonado Bay (Punta del Este Harbor and Gorriti Island) using in vivo, underwater observations and video surveys. The species was first detected in the Río de la Plata (Uruguay and Argentina) in 1999, and by 2004 it had extended its local distribution to Punta del Este at the eastern boundary of the estuary. Observations performed by SCUBA diving showed that R. venosa is preying on native mussels Mytilus edulis and Brachidontes spp., and that formerly abundant mussel beds are being seriously depleted due to a combination of human extraction, habitat deterioration and predation by the Rapa Whelk.  相似文献   

12.
A total of 148 specimens of Mitsukurina owstoni were examined for morphology, distribution, stomach contents, and reproductive condition. Sixty-nine males (81.7–208.5 cm in total length, TL) and 56 females (92.8–196.1 cm TL) were collected with bottom gillnets along a steep slope of the Tokyo Submarine Canyon (100–350 m depth) from May 1995 to October 1996. In addition, data were obtained from 23 specimens of M. owstoni collected from Sagami Bay, Suruga Bay, and the Enshu-nada Sea from 1972 to 2001. Japanese catch records already published (from 1898) plus those in the present study were from the Pacific coast of Japan, from Choshi to the Kii Peninsula. The main fishing season for M. owstoni by bottom gillnet fishing in the Tokyo Submarine Canyon was October to April, at depths of 200–245 m. No specimens examined were sexually mature, including the largest male (208.5 cm TL) and female (196.1 cm TL) recorded. Of 110 stomachs from specimens from the Tokyo Submarine Canyon, 32 (29.1%) were empty. The remainder variously included teleost fishes, squids, decapods, isopods, digested food, and human refuse. Teleost fishes (Macrouridae sp. and Stomiidae spp.), an isopod (Cymothoidae), and decapods (Pasiphaea sinensis and Sergia sp.) were the only identifiable prey, the indication being that teleosts (all size ranges) were of primary importance as prey for M. owstoni.  相似文献   

13.
Here the length–weight relationships (LWRs) of two catfish species are provided. Individuals of Imparfinis mirini Haseman, 1911, and Phenacorhamdia tenebrosa (Schubart, 1964) were collected in August and December 2017 from the Guareí River Basin, upper Paraná River basin, Brazil. Values of b were between 2.66 and 3.11 and a between 0.0122 and 0.0137; statistical analysis showed high r2 values. Lastly, a new record of maximum standard length for P. tenebrosa is provided.  相似文献   

14.
Polymorphism of the BoLA-DRB3 gene was studied with the use of the PCR-RFLP technique in three cattle breeds (Mongolian, Kalmyk, and Yakut) representing the Bos taurus turano-mongolicus group. 35 BoLA-DRB3.2 alleles were detected in the Mongolian breed and 34 alleles in the Kalmyk breed. The frequencies of alleles in both populations are distributed rather evenly: the frequencies of the most widely represented alleles (*18, *20, and *28) in the Mongolian cattle varied from 7.75 to 8.45%. The most frequent alleles in the Kalmyk cattle were *28 (14.52%), *24 (7.26%), and *12 (6.45%). Only five alleles were identified in the Yakut cattle breed. The prevailing allele was *29 (77.3%); a relatively frequent allele was *1 (13.1%), and the remaining three alleles constituted only 9.6%. Such a low level of diversity of BoLA-DRB3 gene alleles was not observed earlier in any other cattle breed. The Mongolian and Kalmyk breeds showed a wide diversity of BoLA-DRB3 genotypes (56 and 51 genotypes, respectively) and a high level of expected heterozygosity (H e = 0.953 and 0.946, respectively). Both breeds had a deficiency of heterozygotes (Mongolian cattle: H o = 0.775, D = −0.187; Kalmyk cattle: H o = 0.708, D = −0.252). A low level of genotypic diversity for the BoLA-DRB3 locus (only seven genotypes; the frequency for the genotype *29/*29 is 71.4%) and a very low level of observed heterozygosity (H o = 0.12) were revealed in the Yakut breed. BoLA-DRB3.2 alleles associated with resistance to persistent lymphocytosis caused by the bovine leukemia virus (total frequencies 15.49 and 24.19%) and to various forms of mastitis (total frequencies 12.68 and 20.96%, respectively) were identified in the Mongolian and Kalmyk animals. In the Yakut breed, alleles associated with resistance to diseases are represented only by the BoLA-DRB3.2 allele *7 (1.2%). Thus, the Mongolian and Kalmyk cattle breeds are characterized by a wide diversity of alleles and genotypes for the BoLA-DRB3 gene. In contrast, the population of Yakut cattle from the Verkhoyanskii region of the Republic of Sakha has a poor diversity of alleles and genotypes for the BoLA-DRB3 gene and a very low level of heterozygosity, suggesting an unfavorable state of the population that is probably caused by inbreeding depression due to a long-term isolation and a small number of animals.  相似文献   

15.
Glycoconjugates in egg extracellular matrices are known to serve several functions in reproductive processes. Here, the presence of N‐linked mannose (Man) glycoconjugates on shrimp thrombospondin ( pmTSP‐II) and their physiological functions were investigated in the black tiger shrimp Penaeus monodon. A molecular analysis of pmTSP‐II demonstrated anchorage sites for N‐linked glycans in both the chitin‐binding and TSP3 domains. The presence of Man residues was verified by concanavalin A lectin histochemistry on the purified fraction of pmTSP‐II (250 kDa with protease inhibitor). The function of the Man glycoconjugates was evident by the Con A interference with the pmTSP‐II‐induced acrosome reaction (AR) as well as by the ability to recover the induction of the AR by the inclusion of Mans in the treatment mixture. In addition, the recombinant proteins of the three signature pmTSP‐II domains expressed in E. coli (lacking glycosylation) and mannosidase‐treated pmTSP‐II showed a minimal ability to initiate the AR response. Together, these results provide evidence of the pivotal role that Man‐linked pmTSP‐II plays in modulating the shrimp sperm AR, a novel role for a TSP family protein in shrimp reproductive biology.  相似文献   

16.
Leaf surface preference of the cabbage worm, Pieris rapae crucivora Boisduval (Lepidoptera: Pieridae), for cabbage, Brassica oleracea L. var. capitata (Brassicaceae), and parasitism by the parasitoid Cotesia glomerata (L.) (Hymenoptera: Braconidae) were investigated experimentally in the laboratory. Female butterflies did not discriminate between the adaxial and abaxial surfaces of cabbage leaves when laying eggs on a vertically placed leaf. Larvae also did not discriminate between the adaxial and abaxial surfaces throughout their larval life. However, second and third instars preferred the lower surface of horizontally placed leaves to the upper surface, irrespective of whether they had hatched on the upper or lower side; other instars showed no preference for the lower surface. Parasitism rates of first and second instars on the upper surface were higher than those of larvae on the lower surface. Egg distribution on leaf surfaces and the leaf surface preference by young larvae are discussed in terms of avoidance of parasitism by the parasitoid C. glomerata.  相似文献   

17.
An endoparasitoid wasp, Cotesia plutellae, induces significant immunosuppression of host insect, Plutella xylostella. This study was focused on suppression in humoral immune response of P. xylostella parasitized by C. plutellae. An EST database of P. xylostella provided a putative cecropin gene (PxCec) which is 627 bp long and encodes 66 amino acids. A signal peptide (22 amino acids) is predicted and two putative O-glycosylation sites in threonine are located at positions 58 and 64. Without bacterial infection, PxCec was expressed in pupa and adult stages but not in the egg and larval stages. Upon bacterial challenge, however, the larvae expressed PxCec as early as 3 h post infection (PI) and maintained high expression levels at 12–24 h PI. By 48 h PI, its expression noticeably diminished. All tested tissues of bacteria-infected P. xylostella showed PxCec expression. However, other microbes, such as virus and fungus, did not induce the PxCec expression. Parasitization by C. plutellae suppressed the expression of PxCec in response to bacterial challenge. Among the parasitic factors of C. plutellae, its symbiotic virus (C. plutellae bracovirus: CpBV) alone was able to inhibit the expression of PxCec of P. xylostella challenged by bacteria. These results indicate that PxCec expression is regulated by both immune and developmental processes in P. xylostella. The parasitization by C. plutellae inhibited the expression of PxCec by the wasp’s symbiotic virus.  相似文献   

18.
Three communities separated by 1.5–7.0 km, along the Matapí River, Amapá State, Brazil, were sampled monthly from April 2003 to November 2005 to determine relationships between seasonal abundance of host‐seeking anophelines, rainfall and malaria cases. Out of the 759 821 adult female anophelines collected, Anopheles darlingi Root (Diptera: Culicidae) was the most abundant (56.2%) followed by An. marajoara Galvão & Damasceno (24.6%), An. nuneztovari Gabaldón (12.4%), An. intermedius (Chagas) (4.4%) and An. triannulatus (Neiva and Pinto) (2.3%). Vector abundance, as measured by human landing catches, fluctuated during the course of the study and varied in species‐specific ways with seasonal patterns of rainfall. Anopheles darlingi and An. triannulatus were more abundant during the wet‐dry transition period in June to August, whereas An. marajoara began to increase in abundance in February in two villages, and during the wet‐dry transition in the other village. Anopheles nuneztovari and An. intermedius increased in abundance shortly after the rains began in January to February. A generalized linear mixed model (GLMM) analysis of 32 consecutive months of collections showed significant differences in abundance for each species by village and date (P < 0.0001). Correlations between lagged rainfall and abundances also differed among species. A strong positive correlation of An. darlingi abundance with rainfall lagged by 4 and 5 months (Pearson's r = 0.472–0.676) was consistent among villages and suggests that rainfall may predict vector abundance. Significant correlations were detected between numbers of malaria cases and abundances of suspected vector species. The present study shows how long‐term field research may connect entomological and climatological correlates with malaria incidence.  相似文献   

19.
Length‐weight (LWRs) and length‐length relationships (LLRs) were determined for four fish species collected from the Atari River in Dinajpur of Bangladesh. Sampling took place monthly between January and June 2016, using seine nets of commercial fishermen (mesh size 4 mm). In LWRs (r2 > .927, < .05), slope (b) was estimated as 3.191, 2.992, 3.217 and 3.109 for Acanthocobitis botia, Botia lohachata, Canthophrys gongota and Chanda nama, respectively. In LLRs (r2 > .812, < .05), lengths i.e. TL, SL, HL and FL were highly correlated. The present study on these species would be the baseline for FishBase dataset.  相似文献   

20.
Agrobacterium tumefaciens-mediated transformation (ATMT) has been successfully applied to the violet root-rot fungus Helicobasidium mompa, which is the causal agent of violet root-rot disease. The A. tumefaciens strains carried a binary plasmid vector containing the hygromycin B phosphotransferase gene (hph) controlled by the heterologous fungal Agaricus bisporus P-gpd (glyceraldehyde-3-phosphate dehydrogenase) promoter and the trpC terminator. The transformation system was optimized using defined cocultivation conditions. When H. mompa strain V17 was cocultivated with A. tumefaciens strain AGL-1 using 5% agar, we obtained more hygromycin-resistant colonies than with strains EHA105 or MAFF301222 using 2% agar. In addition, our results suggest that the activated carbon is necessary in ATMT to reduce background growth of H. mompa. The presence of the hph gene in transformants was detected by polymerase chain reaction (PCR), and single-copy integration of the marker gene was demonstrated by Southern blot analysis. Thus, the ATMT system can be considered a promising tool for insertional mutagenesis studies of H. mompa.  相似文献   

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