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1.
Field-collected adults of the southern pine sawyer, Monochamus titillator (F.) (Coleoptera: Cerambycidae), naturally infested with fourth-stage juveniles (dauerlarvae) of the pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer, 1934) Nickle, 1970, were maturation fed on excised shoots of typical slash pine, Pinus elliottii Engelm. var elliottii, for 21 days. During August 1981, a male and female adult beetle were held in a sleeve cage placed on the terminal of a side branch of each of seven replicate, healthy 10-year-old slash pine trees. All seven branch terminals showed evidence of beetle feeding on the bark after 1 week, and pinewood nematodes were present in wood samples taken near these feeding sites. Four of the seven trees showed wilt symptoms in 4-6 weeks and died about 9 weeks after beetle feeding. Pinewood nematodes were recovered from the roots and trunks of the dead trees. Each of seven replicate slash pine log bolts was enclosed in a jar with a pair of the same beetles used in the sleeve cages. After 1 week, wood underlying beetle oviposition sites in the bark of all replicate log bolts was infested with the pinewood nematode.  相似文献   

2.
Hepatic fibrosis induced by egg deposition is the most serious pathology associated with chronic schistosomiasis, in which the hepatic stellate cell (HSC) plays a central role. While the effect of Schistosoma mansoni eggs on the fibrogenic phenotype of HSCs has been investigated, studies determining the effect of eggs of S . japonicum on HSCs are lacking. Disease caused by S . japonicum is much more severe than that resulting from S. mansoni infection so it is important to compare the pathologies caused by these two parasites, to determine whether this phenotype is due to the species interacting differently with the mammalian host. Accordingly, we investigated the effect of S japonicum eggs on the human HSC cell line, LX-2, with and without TGF-β (Transforming Growth Factor beta) co-treatment, so as to determine the impact on genes associated with fibrogenesis, inflammation and matrix re-organisation. Activation status of HSCs was assessed by αSMA (Alpha Smooth Muscle Actin) immunofluorescence, accumulation of Oil Red O-stained lipid droplets and the relative expression of selected genes associated with activation. The fibrogenic phenotype of HSCs was inhibited by the presence of eggs both with or without TGF-β treatment, as evidenced by a lack of αSMA staining and reduced gene expression of αSMA and Col1A1 (Collagen 1A1). Unlike S. mansoni-treated cells, however, expression of the quiescent HSC marker PPAR-γ (Peroxisome Proliferator-Activated Receptor gamma) was not increased, nor was there accumulation of lipid droplets. In contrast, S . japonicum eggs induced the mRNA expression of MMP-9 (Matrix Metalloproteinase 9), CCL2 (Chemokine (C-C motif) Ligand 2) and IL-6 (Interleukin 6) in HSCs indicating that rather than inducing complete HSC quiescence, the eggs induced a proinflammatory phenotype. These results suggest HSCs in close proximity to S . japonicum eggs in the liver may play a role in the proinflammatory regulation of hepatic granuloma formation.  相似文献   

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The latifrons species-group (=Brachycallimerus sensu Chapin 1924, Corporaal 1950; = flavofasciatus-group sensu Kolibáč 1998) of Callimerus Gorham is redefined and revised. Five species are recognized including one new species Callimerus cacuminis Yang & Yang sp. n. (type locality: Yunnan, China). Callimerus flavofasciatus Schenkling, 1902 is newly synonymized with Callimerus latifrons Gorham, 1876. Callimerus trifasciatus Schenkling, 1899a is transferred to the genus Corynommadius Schenkling, 1899a. Callimerus gorhami Corporaal, 1949 and Callimerus pallidus Gorham, 1892 are excluded from the latifrons species-group (their assignment to a species-group will be dealt with in a subsequent paper). A key to species of the latifrons species-group is given and habitus of each type specimen, male terminalia, and other diagnostic characters are illustrated.  相似文献   

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We determined the temporal and seasonal dynamics of intra-annual cell formation of south Florida slash pine (Pinus elliottii Engelm. var. densa Little & Dor.), the southernmost native pine in the United States and the foundation species of globally endangered pine rockland ecosystems. To assess intra-annual cambial activity and identify possible relationships between cell production and climatic factors, wood micro-cores were extracted monthly from six trees during the period March 2010 to March 2011. The results confirmed annual growth ring formation in P. elliottii var. densa and indicated that its growing season extends from February to December, with a short period of dormancy that varied little between individuals. Within the growing season, earlywood cells were produced from February to July, latewood cells produced from July to December, and intra-annual density fluctuations (IADFs) occurred in the growth rings of four of six trees between July and August. A principal component analysis indicated a homogeneous response of cambial activity among trees to site-specific climatic factors. The first principal component axis explained 71?% of the total variance in cell production during the study period. Our results indicated that the dynamics of seasonal cambial activity of P. elliottii var. densa are controlled by solar radiation (r?=?0.51, p?<?0.10) in the Florida Keys. The nature of our data allow us to only speculate on the ecophysiological processes responsible for IADFs in P. elliottii var. densa, and additional research is needed to better understand the relationship between their formation and the environment in the Lower Florida Keys.  相似文献   

7.
Third instar larvae of members of the Ceratitis FAR complex, including Ceratitis fasciventris (Bezzi), Ceratitis anonae Graham, and Ceratitis rosa Karsch are described and compared with those of Ceratitis capitata (Wiedemann). Diagnostic characters, such as presence vs. absence of a secondary tooth on the mandibles, previously used to separate Ceratitis capitata from Ceratitis rosa, are shown to vary in each species. Significant variation in diagnostic morphological characters among populations of Ceratitis rosa from east and south Africa is documented; however, the differences are not simply congruent with the R1 and R2 designations based on other studies. Quantitative measures of numerous morphological characters are consistently smaller in the larvae of Ceratitis fasciventris and distinguish them from other species of the FAR complex. Larvae of Ceratitis capitata can be distinguished from those of the FAR complex by characters such as absence of accessory plates of the oral ridges, the shape of the anterior spiracle, and the pattern of dorsal spinules. Previous studies indicated that absence of accessory lobes separate the genus Ceratitis from Bactrocera, but this is shown to be incorrect, as accessory lobes are in fact present in several species of Ceratitis.  相似文献   

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Dictyostelium discoideum amoebae have been used extensively to study the structure and dynamics of the endocytic pathway. Here, we show that while the general structure of the endocytic pathway is maintained in starved cells, its dynamics rapidly slow down. In addition, analysis of apm3 and lvsB mutants reveals that the functional organization of the endocytic pathway is profoundly modified upon starvation. Indeed, in these mutant cells, some of the defects observed in rich medium persist in starved cells, notably an abnormally slow transfer of endocytosed material between endocytic compartments. Other parameters, such as endocytosis of the fluid phase or the rate of fusion of postlysosomes to the cell surface, vary dramatically upon starvation. Studying the endocytic pathway in starved cells can provide a different perspective, allowing the primary (invariant) defects resulting from specific mutations to be distinguished from their secondary (conditional) consequences.Dictyostelium discoideum is a widely used model organism for studying the organization and function of the endocytic pathway. In Dictyostelium, the organization of the endocytic pathway is similar to that in higher eukaryotes. The pathway in Dictyostelium can be divided into four steps (see Fig. S1 in the supplemental material): uptake at the plasma membrane of particles and medium, transfer through early acidic endocytic compartments (lysosomes), passage into less acidic postlysosomes (PLs), and finally, exocytosis of undigested materials (17, 20). Thus, Dictyostelium recapitulates many of the functions of the endocytic pathway in mammalian cells, including some features observed in most cell types (lysosome biogenesis) and some observed only in specialized cells (phagocytosis, macropinocytosis, and lysosome secretion).Dictyostelium amoebae live in the soil, where they feed by ingesting and digesting other microorganisms. In addition, axenic laboratory strains can macropinocytose medium to ensure their growth. Accordingly, both in natural situations and in laboratory settings, the endocytic pathway plays a key role in the acquisition of nutrients by Dictyostelium cells. In agreement with this notion, several observations suggest that the physiology of the endocytic pathway is sensitive to nutrient availability. In particular, starvation induces secretion of lysosomal enzymes by an unknown mechanism (11). The morphology of the endocytic pathway is also sensitive to nutritional cues, as shown for example by the observation that formation of multilamellar endosomes is enhanced in cells fed with bacteria (18).Here, we analyzed the effect of starvation on the organization as well as the dynamics of the endocytic pathway. We found that, while the overall organization was not extensively modified in starved cells, the dynamics of endocytic compartments were altered. Moreover, analysis of two specific knockout mutants, the apm3 (6) and lvsB (8) strains, revealed that their phenotype was profoundly altered upon starvation, providing further insight about the role of Apm3 and LvsB in the endocytic pathway.  相似文献   

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Scanning electron microscopy (SEM) of second-stage juveniles (J2), males, and females of Meloidodera floridensis, M. charis, M. belli, and Verutus volvingentis reveals detailed characteristics of the head region, lateral field, phasmid, body striae, vulva, and perineal region. In M. charis and M. belli the en face pattern conforms to a basic pattern in which the labial disc is surrounded by six lips (sectors) of the first head annulation. In J2 the head has additional annulations, whereas in males annulation is replaced by longitudinal blocks. Conversely, J2 and males of M. floridensis and V. volvingentis each have a unique derived face pattern with fusion of various lip components and with head annulation. All six lips of females of M. charis and M. belli are fused, whereas females of M. floridensis and V. volvingentis have distinct lateral lips. Lateral fields vary among species, with only slight differences at the anterior and posterior ends of the lateral lines and in the spatial relation of the lines to phasmid openings. Phasmid openings are present in adults of Meloidodera spp., but were not observed in adults of V. volvingentis; in this respect, the female perineal pattern of Verutus is different from Meloidodera spp, The very large vulva (± 48 μm long) of V. volvingentis is in sharp contrast to the minute vulva (± 6 μm long) in a population of M. charis from San Bernardino. Morphological characters revealed by SEM will be most informative when investigated throughout Heteroderidae and incorporated with additional characters for a phylogenetic analysis of the family.  相似文献   

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Two new species of nematodes from southern Chile are described and illustrated. Pratylenchus australis n. sp. is distinguished by its heavy cephalic sclerotization, smooth tail terminus, lack of spermatheca, and absence of males. Eutylenchus fueguensis n. sp. differs from other Eutylenchus spp. by the long female stylet (31 [28-32] μm), strongly sclerotized excretory duct opening posterior to nerve ring, and broadly rounded caudal alae of males.  相似文献   

15.
In the current study, we tested the in vivo effects of Yy1 gene dosage on the Peg3 imprinted domain with various breeding schemes utilizing two sets of mutant alleles. The results indicated that a half dosage of Yy1 coincides with the up-regulation of Peg3 and Zim1, suggesting a repressor role of Yy1 in this imprinted domain. This repressor role of Yy1 is consistent with the observations derived from previous in vitro studies. The current study also provided an unexpected observation that the maternal allele of Peg3 is also normally expressed, and thus the expression of Peg3 is bi-allelic in the specific areas of the brain, including the choroid plexus, the PVN (Paraventricular Nucleus) and the SON (Supraoptic Nucleus) of the hypothalamus. The exact roles of the maternal allele of Peg3 in these cell types are currently unknown, but this new finding confirms the previous prediction that the maternal allele may be functional in specific cell types based on the lethality associated with the homozygotes for several mutant alleles of the Peg3 locus. Overall, these results confirm the repressor role of Yy1 in the Peg3 domain and also provide a new insight regarding the bi-allelic expression of Peg3 in mouse brain.  相似文献   

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There are four species of Gymnetron in China recorded to date including Gymnetron miyoshii Miyoshi, 1922, Gymnetron villosipenne Roelofs, 1875, Gymnetron auliense Reitter, 1907 and Gymnetron vittipenne Marseul, 1876, of which the last two are new country records. The pre-imaginal stages including eggs, mature larvae and pupae of Gymnetron miyoshii, Gymnetron auliense and Gymnetron vittipenne are described and illustrated. In addition, their diagnostic characters (larvae and pupae) are discussed and differentiated, and notes on some of their biological parameters are provided. Potential ecological impacts between Gymnetron weevils and their host Veronica spp. also are provided.  相似文献   

18.
Araucaria forests in Brazil today correspond to only 0.7 % of the original 200 km2 of natural forest that covered a great part of the southern and southeastern area of the Atlantic Forest and, although Araucaria angustifolia is an endangered species, illegal exploitation is still going on. As an alternative to the use of hardwoods, Pinus elliottii presents rapid growth and high tolerance to climatic stress and low soil fertility or degraded areas. Thus, the objective of this study was to evaluate the effect of IAA-producing bacteria on the development of A. angustifolia and P. elliottii. We used five bacterial strains previously isolated from the rhizosphere of A. angustifolia, which produce quantities of IAA ranging from 3 to 126 μg mL?1. Microbiolized seeds were sown in a new gnotobiotic system developed for this work, that allowed the quantification of the plant hormone IAA produced by bacteria, and the evaluation of its effect on seedling development. Also, it was shown that P. elliottii roots were almost as satisfactory as hosts for these IAA producers as A. angustifolia, while different magnitudes of mass increases were found for each species. Thus, we suggest that these microbial groups can be helpful for the development and reestablishment of already degraded forests and that PGPR isolated from Araucaria rhizosphere have the potential to be beneficial in seedling production of P. elliottii. Another finding is that our newly developed gnotobiotic system is highly satisfactory for the evaluation of this effect.  相似文献   

19.
A new species of Pseudascarophis (Nematoda: Cystidicolidae) found in the stomach of Kyphosus sectatrix (Linnaeus) (Kyphosidae), off Rio de Janeiro, Brazil, is described. The new species can be differentiated from the other congeners by the presence of lateral alae, distinct but inconspicuous cephalic papillae at the anterior end, three pairs of precloacal and one pair of adcloacal papillae in males, egg morphology and morphometry of glandular oesophagus and spicules. Pseudascarophis tropica is transferred to Ascarophis as Ascarophis tropica (Solov''eva) comb. n. due to its ambiguous diagnosis.  相似文献   

20.
Pratylenchoides hispaniensis n. sp. is described and illustrated from a bisexual population found in a natural habitat at Santa Elena, Jaen, central Spain. Its main distinctive characters are very long esophageal gland lobe (81-117 μm; N'' = 51-71) overlapping the intestine 3 to 5 times the body width; lateral field with six incisures; stylet knobs sloping posteriorly; labial disc encircled by the irregular sectors of the first annule; tail cylindrical, extremity annulated, and frequently with a slight dorsal indentation of the hyaline portion at the end of the lateral field. Pratylcnchoides hispaniensis n. sp. appears closely related to P. megalobatus and P. nevadensis. It differs from the former primarily by its longer body length (761-998 vs. 430-621 μm), longer stylet length (20.5-24.4 vs. 18-21 μm), six incisures in the lateral field vs. four for P. megalobatus, and posteriorly sloping stylet knobs vs. rounded or anteriorly flattened knobs in P. megalobatus. It differs from P. nevadensis mainly by the shape of the stylet knobs (sloping in P. hispaniensis vs. rounded in P. nevadensis), length of esophageal lobe (81-117 vs. 34-82 μm), and position of esophageal gland nuclei (all posterior to esophago-intestinal junction in P. hispaniensis vs. at least one nucleus anterior to junction in P. nevadensis).  相似文献   

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