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1.
Raillietina melomyos n. sp. from the small intestine ofMelomys rufescens in the Western Highlands of Papua New Guinea differs from related species in combinations of the number (170–190) and length (8–11 m) of the rostellar hooks, the number of testes (21–36) and of egg capsules per gravid proglottid (56–92), and in that the cirrus-sac does not reach the longitudinal osmoregulatory canals.  相似文献   

2.
The effects of medium strategies [maintenance (M), intermediary (G), and production (P) medium] on cell growth, anthraquinone (AQ) production, hydrogen peroxide (H2O2) level, lipid peroxidation, and antioxidant vitamins in Morinda elliptica cell suspension cultures were investigated. These were compared with third-stage leaf and 1-month-old callus culture. With P medium strategy, cell growth at 49 g l–1, intracellular AQ content at 42 mg g–1 DW, and H2O2 level at 9 mol g–1 FW medium were the highest as compared to the others. However, the extent of lipid peroxidation at 40.4 nmol g–1 FW and total carotenoids at 13.3 mg g–1 FW for cultures in P medium were comparable to that in the leaf, which had registered sevenfold lower AQ and 2.2-fold lower H2O2 levels. Vitamin C content at 30–120 g g–1 FW in all culture systems was almost half the leaf content. On the other hand, vitamin E content was around 400–500 g g–1 FW in 7-day-old cultures from all medium strategies and reduced to 50–150 g g–1 FW on day 14 and 21; as compared to 60 g g–1 FW in callus and 200 g g–1 FW in the leaf. This study suggests that medium strategies and cell growth phase in cell culture could influence the competition between primary and secondary metabolism, oxidative stresses and antioxidative measures. When compared with the leaf metabolism, these activities are dynamic depending on the types and availability of antioxidants.Abbreviations AQ Anthraquinone - DW Dry cell weight - FW Fresh cell weight - G Intermediary medium - M Maintenance medium - MDA Malondialdehyde - P Production medium - ROS Reactive oxygen species - TBA Thiobarbituric acid - td Doubling time  相似文献   

3.
The authors describe and illustrate two hymenolepidid cestodes parasitising Himantopus melanurus (Aves) from Paraguay. Microsomacanthus kaulobatroni n. sp., 20–30 long × 0.6 mm wide, with 10 diorchoid hooks 33–38 µm long, three testes in a transverse row, short cirrus 20–28 µm long armed with very minute spines, a short vagina with a sphincter, and a multi-lobed ovary, with genital ducts similar to those of Hymenolepis himantopodis ( sensu Fuhrmann, 1906) but with rostellar hooks different from those of Tænia himantopodis Krabbe, 1869 sp. inq. Wardium neotropicale n. sp., 40-50 long x 0.9 mm wide, has campanulate proglottides, scolex with 10 aploparaksoid rostellar hooks 9 µm long, testes arranged in a triangle, a short cirrus pouch without a transverse retractor muscle, very short, unarmed cirrus, a short vagina with a sphincter (30–35 µm in diameter) but no retractor muscle, a multi-lobed ovary and a bipartite uterus. The shape of the hooks distinguishes this species from T. himantopodis Krabbe, 1869 and other aspects of its anatomy from other species of Wardium with hooks of a similar size. A single specimen of a third Hymenolepis (sensu lato) species (lacking the scolex) could not be identified.  相似文献   

4.
Porphyra vietnamensis Tanaka & Pham-Hoang Ho is a tropical species of high potential for farming. Studies of the life cycle have been conducted for many years but have not been successful until recently. Mature thalli were collected from Songkhla, in the southern part of Thailand, and were used to obtain Conchocelis in the laboratory in Bangkok. Conchocelis in shells as well as free-floating filaments could be observed after one week of incubation at 25 °C, 25 salinity and 350–500 lux light intensity, and covered the culture shell surface within 2 months. Conchosporangia were formed after being incubated for 10 days at 30 °C, 20 salinity under light intensities of 350–500 lux with a photoperiod of 12 hours a day. Induction of conchospore release was achieved by lowering the temperature to 25 °C and the salinity to 10–15 and increasing the light intensity to 800–1000 lux. Liberated conchospores germinated into young thalli which became mature after 70 days.  相似文献   

5.
Acanthobothrium marplatensis n. sp. is described from the spiral intestine of the skate Rioraja castelnaui taken off Mar del Plata, Argentina. The new species is compared with those species that it most closely resembles morphologically, to species reported from other skate hosts and to species described from the same geographical region. A. marplatensis is most similar to A. paulum, A. benedeni, A. costarricense, A. fogeli, A. himanturi, A. lintoni, A. monksi, A. olseni, A. puntarenasense and A. mathiasi. All of these species share a similar combination of characters (12–40 proglottids, 20–50 testes and total length of 2–10mm). A. marplatensis can be differentiated from these species and those described from skates by a combination of the following characters: 4.79–8.44 (6.18) mm long, with 18–30 (24) proglottids, spinose cephalic peduncle 160–338 (227) long, bothridial hooks with total length 93-134 (115), 24–39 (32) testes per proglottid, cirrus-sac curved anteriorly, ovarian lobes never reaching the level of the cirrus-sac and vaginal sphincter absent. Geographically, the new species can be distinguished from A. zapterycum and three different species designated as Acanthobothrium sp. reported from the coast of Uruguay and Argentina by the size of the worms, number of proglottids, position of the genital pores and size of the bothridial hooks. A. marplatensis showed the greatest preference for chambers 2 and 3 of the eight chambers of the spiral intestine. The mean intensity of infection in individual hosts increased with host size and was greater in spring and summer than in cold seasons. The intensity of infection was unrelated to host sex.  相似文献   

6.
Summary Sobolevicanthus dlouhyi n. sp. is close to S. krabbeella but differs from it firstly by the longer rostellar hooks (83–85 m instead of 56–64 m). The cirrus pouch is shorter in the new species, no longer than the width of the widest proglottis, whereas in S. krabbeella it is twice as long. ac]19810312  相似文献   

7.
A new species of Alcataenia is described from razorbills Alca torda Linnaeus from the southern region of the North Sea in the coastal waters of Belgium. It differs from known species of the genus in having 18–20 rostellar hooks measuring 63–74 m in length. Other attributes include a cirrus-sac 145–228 m in length, 36–49 testes and a vitelline gland measuring 114–202 × 59–112 m. This is the first species of Alcataenia described from razorbills and appears to be the only member of the genus which is endemic to the North Atlantic basin.  相似文献   

8.
Atactorhynchus duranguensisn. sp. (Acanthocephala: Atactorhynchinae) is described from the intestine of Cyprinodon meeki Miller, an endemic freshwater fish from a far-inland locality of Mexico. Diagnostic features include: body small, stout, ventrally curved; small cylindrical proboscis armed with 16 alternating vertical rows of four or five hooks; anterior two or three hooks conspicuous, stout and larger than other hooks, and have large, rod-shaped roots with a markedly and abruptly enlarged base; three posterior hooks of each row are smaller and rootless; single-walled proboscis receptacle; lemnisci equal in length, elongate and robust; and cement gland syncytial, larger than testis. The new species is smaller than A. verecundus Chandler, 1935, the only previously described species in the genus. The shape of the proboscis of the new species is strikingly different from that of A. verecundus, which is widest at the apex. Likewise, the greatest width of the trunk of the new species is in about the middle, differing from that of A. verecundus where the trunk is widest posteriorly. The new species also can be distinguished from A. verecundus because of its much smaller hook lengths and slightly smaller proboscis. In addition, the proportion of large apical proboscis hooks in relation to the small basal hooks is different: the basal hooks of A. verecundus are about half the size of the anterior hooks and but only about a quarter of the size in A. duranguensis. Unlike A. verecundus, the base of the roots are markedly and abruptly enlarged in the new species. Finally, the eggs of the new species are smaller (23–27 × 8–10 m) than those of A. verecundus (27–30 × 12–13 m).  相似文献   

9.
The effect of a homologous series of octylphenoxy surfactants, -[4-(1,1,3,3-tetramethylbutyl)phenyl]--hydroxypoly-(oxy-1,2-ethanediyl), condensed with 5, 7–8, 9–10, 16, and 30 oxyethylene (EO) units on enhancement of gibberellic acid (GA3) absorption by leaves ofPrunus cerasus cv. Montmorency was studied. Increasing EO chain length (5–30 EO) increased surface tension (27.5–35.3 mN m–1) and contact angles on adaxial (21–36°) and abaxial (28–49°) leaf surfaces. With increasing EO content, the form of GA3 deposits from droplets on the leaf surface changed from an annulus shape (5 and 7–8 EO) to globular forms covering increasingly smaller interface areas (9–10 to 30 EO). The surfactants increased GA3 uptake, the magnitude decreased with an increase in oxyethylene chain length. Similar trends were found for both the adaxial and abaxial surfaces. Penetration through the abaxial surface was linearly related to the logarithm of the oxyethylene content of the surfactant molecule (r 2=0.934**) and to the hydrophilic: lipophilic balance (r 2=0.926**). Absorption by the abaxial surface was approximately one order of magnitude greater than by the adaxial surface.  相似文献   

10.
The number and biomass of prey captured were estimated for Pinguicula alpina, P. villosa and P. vulgaris in a subarctic environment. Seasonal captures were estimated for one site per species for 4–5 years. Captures were related to reproductive status (reproductive/non-reproductive) and to leaf area. For one species (P. vulgaris) the catch was also compared across a range of habitats. Of the seasonal catch, 50–75% was obtained during June and less than 5% during August. For P. alpina and P. villosa the seasonal catch varied threefold or more between years (means of 89–329 g dry matter plant–1 season–1 for P. alpina, and 11–91 g dry matter plant–1 season–1 for P. villosa), whereas the between-year variation for P. vulgaris was small (mean c. 600 g plant–1 season–1). Large variations were, however, observed among habitats for P. vulgaris. Captured prey may contribute a substantial amount of nutrients to the most successful individuals (up to 85% of the mean seasonal turnover), but prey capture varied greatly and during any given season many individuals obtained only marginal amounts of nutrients through carnivory. P. vulgaris trapped almost twice as much per unit leaf area and season as the other two species (224 for P. vulgaris versus 127 g cm–2 season–1 for the other two species). Reproductive individuals of P. vulgaris trapped almost twice as much as non-reproductive individuals (after taking differences in leaf area into account). For the other two species no differences were observed between reproductive and non-reproductive individuals.  相似文献   

11.
The biology of Hypoaspis miles Berlese (Acarina: Hypoaspidae) fed on mushroom sciarid larvae (Lycoriella solani Winnertz) (Diptera: Lycoriidae) and mould mites (Tyrophagus putrescentiae Schrank) (Acari: Acaridae), was investigated by laboratory experiments at 20 °C, 75% r.h. and LD16:D8 hours. H. miles had a significantly shorter development time and a significantly lower juvenile mortality when fed on sciarid larvae than on mould mites, the development time being 14.5 days and the mortality 3.5% on the former prey. The preoviposition and postoviposition periods of H. miles were not uninfluenced by the prey species and were 5–9 and 32–37 days, respectively. Oviposition periods of 53.2 and 68.5 days and female longevities of 82 and 109.6 days were observed on diets of sciarid larvae and mould mites, respectively. Male longevity (168–219 days) was uninfluenced by the prey species. The egg production of H. miles on sciarid larvae was estimated to be 44.4 ± 4.33 eggs per female, as compared to 22.43 ± 1.79 eggs per female on mould mites. The sex-ratio of the offspring was significantly influenced by the prey species, the ratios (/(+)) being 0.66 on sciarid larvae and 0.54 on mould mites. The net reproductive rate (R0) for H. miles fed on sciarid larvae was approximately 27 which was three times higher than for mites feeding on mould mites. The innate capacity of increase (rm) was highest (0.0747 day–1) when sciarid larvae served as food, giving a doubling time of 9.3 days as compared to 12.8 days on mould mites. The generation times were 44.28 on sciarid larvae and 40.67 days on mould mites. The daily food consumption rate of juvenile and adult H. miles was 0.24 and 0.86 sciarid larvae and 10.8 and 21.7 mould mites, respectively. In terms of weight consumed, however, the consumption of sciarid larvae was 2–3.5 times the weight of mould mites. The ratio of females to males influenced the oviposition period and egg production of H. miles, with virgin females laying fewer eggs over a longer period of time as compared with females with access to males. The egg production in relation to the sex-ratio was described by models predicting a maximum number of eggs per female of 22.3 to be attained at a sex ratio of 0.69 (/(+)) and a maximum daily number of eggs per female of 0.33 to be attained at a sex ratio of 0.37 (/(+)).  相似文献   

12.
Gyrodactylus pictae n. sp. is recorded from Poecilia picta in heterospecific shoals with the guppy P.reticulata in Northern Trinidad. G. pictae is morphologically similar to G. turnbulli Harris, 1986, but the hamuli and marginal hooks are slightly smaller and more gracile. The toe and the point of the marginal hook have a distinctly different shape, providing the best morphological characters for distinguishing the two species. The rDNA ITS1 and ITS2 sequences differ from those of G. turnbulli (the closest relative) by >5, suggesting that these two taxa are not sibling species. The origin of the two species on poeciliids of the subgenus Micropoecilia is discussed, and it is suggested that this may represent a case of host–parasite co-evolution.  相似文献   

13.
Three Bromeliaceae species of the medium Orinoco basin, Venezuela, were compared in their light-use characteristics. The bromeliads studied were two species of pineapple, i.e. the wild species Ananas ananassoides originating from the floor of covered moist forest, and the primitive cultivar Panare of Ananas comosus mostly cultivated in semi-shaded palm swamps, and Pitcairnia pruinosa, a species abundant in highly sun exposed sites on rock outcrops. Ananas species are Crassulacean acid metabolism (CAM) plants, P. pruinosa is C3 plant. Plants were grown at low daily irradiance (LL = 1.3 mol m–2 d–1 corresponding to an incident irradiance of 30 mol m–2 s–1) and at high irradiance (HL = 14.7 mol m–2 d–1 or 340 mol m–2 s–1), and CO2 and H2O-vapour gas exchange and photochemical (qP) and non-photochemical quenching (qNP) of chlorophyll a fluorescence of photosystem 2 (PS2) were measured after transfer to LL, medium irradiance (ML = 4.1 mol m–2 d–1 or 95 mol m–2 s–1) and HL. All plants showed flexible light-use, and qP was kept high under all conditions. LL-grown plants of Ananas showed particularly high rates of CAM-photosynthesis when transferred to HL and were not photoinhibited.  相似文献   

14.
Summary Growth of Pisidium casertanum and P. subtruncatum from the profundal of the eutrophic Lake Esrom was followed at four temperatures in the laboratory. The growth rate of both species increased with increasing temperature, but the maximum in P. casertanum was attained at 12° C, instead of at 20° C as in P. subtruncatum. The variation of Q10 of growth in relation to animal weight was of similar form in both species at higher temperatures (6–12°C) but opposite at low temperatures (2–6°C). In the latter case Q10 of P. casertanum had a peak and that of P. subtruncatum a low value at a corresponding size preceding maturity. At constant temperatures growth curves of the form y=a+bx+cx2 were obtained, where y is weight in g and x is time in days. The growth of both species under natural conditions was simulated by use of the experimental growth rate equation and natural birth periods, sizes at birth, and temperature cycles. These simulations gave a maximum life span of 2.5–3 years for P. casertanum and 3.5–4.5 years for P. subtruncatum. The latter species showed slower growth rates at the low or medium temperatures prevailing in the profundal of this lake. A comparison with growth in nature reveals that the simulation overestimated growth in case of P. casertanum.  相似文献   

15.
Various ecophysiological investigations on carnivorous plants in wet soils are presented. Radial oxygen loss from roots of Droseraceae to an anoxic medium was relatively low 0.02 – 0.07 mol(O2) m– 2 s–1 in the apical zone, while values of about one order of magnitude greater were found in both Sarracenia rubra roots and Genlisea violacea traps. Aerobic respiration rates were in the range of 1.6 – 5.6 mol kg–1 (f.m.) s–1 for apical root segments of seven carnivorous plant species and 0.4 – 1.1 mol kg–1 (f.m.) s–1 for Genlisea traps. The rate of anaerobic fermentation in roots of two Drosera species was only 5 – 14 % of the aerobic respiration. Neither 0.2 mM NaN3 nor 0.5 mM KCN influenced respiration rate of roots and traps. In all species, the proportion of cyanide-resistant respiration was high and amounted to 65 – 89 % of the total value. Mean rates of water exudation from excised roots of 12 species ranged between 0.4 – 336 mm 3 kg–1 (f.m.) s–1 with the highest values being found in the Droseraceae. Exudation from roots was insensitive to respiration inhibitors. No significant difference was found between exudation rates from roots growing in situ in anoxic soil and those kept in an aerated aquatic medium. Carnivorous plant roots appear to be physiologically very active and well adapted to endure permanent soil anoxia.  相似文献   

16.
The outer membrane protein, OmpC, from Escherichia coli was used to display metal-binding poly-histidine peptides on the surface of this bacterium. SDS-PAGE analysis of outer membrane protein preparations confirmed the expression of the metal-binding epitopes inserted in position 162 of the mature OmpC protein. Display of these epitopes was confirmed by epifluorescence microscopy of cells bound to Ni2+-NTA-agarose beads and metal adsorption experiments. The cells harboring one or two copies of the metal binding epitope were able to adsorb 3 to 6 times more Zn2+ (13.8 mol g–1 cell), Fe3+ (35.3 mol g–1 cell), and Ni2+ (9.9 mol g–1 cell) metallic ions than control cells expressing the wild-type OmpC.  相似文献   

17.
18.
The mitochondrial inner membrane anion channel (IMAC) is a channel, identified by flux studies in intact mitochondria, which has a broad anion selectivity and is maintained closed or inactive by matrix Mg2+ and H+. We now present evidence that this channel, like many other chloride/anion channels, is reversibly blocked/inhibited by stilbene-2,2-disulfonates. Inhibition of malonate transport approaches 100% with IC50 values of 26, 44, and 88 M for DIDS, H2-DIDS, and SITS respectively and Hill coefficients 1. In contrast, inhibition of Cl transport is incomplete, reaching a maximum of about 30% at pH 7.4 and 65% at pH 8.4 with an IC50 which is severalfold higher than that for malonate. The IC50 for malonate transport is decreased about 50% by pretreatment of the mitochondria withN-ethylmaleimide. Raising the assay pH from 7.4 to 8.4 increases the IC50 by about 50%, but under conditions where only the matrix pH is made alkaline the IC50 is decreased slightly. These properties and competition studies suggest that DIDS inhibits by binding to the same site as Cibacron blue 3GA. In contrast, DIDS does not appear to compete with the fluorescein derivative Erythrosin B for inhibition. These findings not only provide further evidence that IMAC may be more closely related to other Cl channels than previously thought, but also suggest that other Cl channels may be sensitive to some of the many regulators of IMAC which have been identified.  相似文献   

19.
Antarctic fishes were sampled with 41 midwater and 6 benthic trawls during the 1999–2000 austral summer in the eastern Ross Sea. The oceanic pelagic assemblage (0–1,000 m) contained Electrona antarctica, Gymnoscopelus opisthopterus, Bathylagus antarcticus, Cyclothone kobayashii and Notolepis coatsi. These were replaced over the shelf by notothenioids, primarily Pleuragramma antarcticum. Pelagic biomass was low and concentrated below 500 m. The demersal assemblage was characteristic of East Antarctica and included seven species each of Artedidraconidae, Bathydraconidae and Channichthyidae, ten species of Nototheniidae, and three species each of Rajidae and Zoarcidae. Common species were Trematomus eulepidotus (36.5%), T. scotti (32.0%), Prionodraco evansii (4.9%), T. loennbergii (4.7%) and Chaenodraco wilsoni (4.3%). Diversity indices were highest for tows from 450 to 517 m (H=1.90–2.35). Benthic biomass ranged from 0.7 to 3.5 t km–2. It was generally higher in tows from 450 to 517 m (0.9–2.0 t km–2) although the highest biomass occurred at an inner-shelf station (238 m) due to large catches of T. eulepidotus, T. scotti and P. evansii.  相似文献   

20.
The distribution, behavior and metabolism of the mesopelagic jellyfish, Periphylla periphylla (Péron & Lesueur), were investigated in Lurefjorden, Norway. Field studies, conducted in 1998–1999 with plankton nets and a remotely operated vehicle, indicated that 80-90% of the dense (up to 2.5 m–3) population migrated 200–400 m vertically each day throughout the year. In situ observations with red light revealed that swimming rates and feeding activity varied with age and time of day. Detection of turbulence and contact with surfaces caused this medusa to conceal one or all of its tentacles in the stomach or to shed nematocyst-laden tissue from the tentacles. Stomachs of medusae collected with nets were often full of prey entangled with the sloughed tissue. Stomachs of medusae captured individually with ROV samplers were empty or contained only a few prey in their stomachs (typically, 1–4 copepods Calanus spp. or chaetognaths Eukrohnia hamata Möbius per medusa). Low rates (0.4–5.6 l O2 mg C–1 h–1) of oxygen consumption of P. periphylla suggested that this species was sustained by relatively few (1–34) prey d–1.  相似文献   

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