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1.
Hybridization is regarded as a rapid mechanism for increasing genetic variation that can potentially enhance invasiveness. Tamarix hybrids appear to be the dominant genotypes in their invasions. Exotic Tamarix are declared invasive in South Africa and the exotic T. chinensis and T. ramosissima are known to hybridize between themselves, and with the indigenous T. usneoides. However, until now, it was not known which species or hybrid is the most prevalent in the invasion. With a biocontrol programme being considered as a way of suppressing the alien Tamarix populations, it is important to document the population genetic dynamics of all species in the region. This investigation sought to identify Tamarix species in southern Africa and their hybrids, describe their population structure, and reveal the geographic origin of the invasive species. To achieve this, nuclear Internal Transcribed Spacer (ITS) sequence data and the multilocus Amplified Fragment Length Polymorphisms (AFLPs) markers were used. Phylogenetic analysis and population genetic structure confirmed the presence of three species in South Africa (T. chinensis, T. ramosissima and T. usneoides) with their hybrids. The indigenous T. usneoides is clearly genetically distant from the alien species T. chinensis and T. ramosissima. Interestingly, the Tamarix infestation in South Africa is dominated (64.7 %) by hybrids between T. chinensis and T. ramosissima. The exotic species match their counterparts from their places of origin in Eurasia, as well as those forming part of the invasion in the US.  相似文献   

2.
3.
Farnesol is a quorum-sensing molecule that inhibits biofilm formation in Candida albicans. Previous in vitro data suggest that, in combination with certain antifungals, farnesol may have an adjuvant anti-biofilm agent. However, the in vivo efficacy of farnesol is very questionable. Therefore, the in vitro and in vivo activity of fluconazole combined with farnesol was evaluated against C. albicans biofilms using fractional inhibitory concentration index (FICI) determination, time-kill experiments and a murine vulvovaginitis model. The median biofilm MICs of fluconazole-sensitive C. albicans isolates ranged between 4 -> 512 mg/L and 150–300 μM for fluconazole and farnesol, respectively. These values were 512 -> 512 mg/L and > 300 μM for fluconazole-resistant clinical isolates. Farnesol decreased the median MICs of fluconazole by 2-64-fold for biofilms. Based on FICI, synergistic interaction was observed only in the case of the sessile SC5314 reference strain (FICIs: 0.16–0.27). In time-kill studies, only the 512 mg/L fluconazole and 512 mg/L fluconazole + 75 μM farnesol reduced biofilm mass significantly at each time point in the case of all isolates. The combination reduced the metabolic activity of biofilms for all isolates in a concentration- and time-dependent manner. Our findings revealed that farnesol alone was not protective in a murine vulvovaginitis model. Farnesol was not beneficial in combination with fluconazole for fluconazole-susceptible isolates, but partially increased fluconazole activity against one fluconazole-resistant isolate, but not the other one.  相似文献   

4.
The aporocotylid fauna of the mottled spinefoot, Siganus fuscescens (Houttuyn), from Moreton Bay, Queensland, Australia, was characterised using a combined morphological and molecular approach. Four aporocotylid species were identified, three belonging to the genus Ankistromeces Nolan & Cribb, 2006 and one to Cardicola Short, 1953. Specimens of Cardicola matched an undescribed species from the same host and locality; this species is described as Cardicola mogilae n. sp. Phylogenetic analyses of ITS2 and 28S data showed that C. mogilae n. sp. forms a strongly supported clade with other Cardicola species from siganid fishes. We record Ankistromeces olsoni Nolan & Cribb, 2006 in Moreton Bay for the first time, redescribe A. dunwichensis Nolan & Cribb, 2006 on the basis of new specimens and sequence data and re-report Ankistromeces sp. X from Moreton Bay based on molecular data. We review the status of the ten putative species of aporocotylids reported from siganids. Small variation in ITS2 rDNA sequences, in association with different geographic localities, was previously used to separate Cardicola lafii Nolan & Cribb, 2006 from C. parilus Nolan & Cribb, 2006, C. bartolii Nolan & Cribb, 2006 from C. watsonensis Nolan & Cribb, 2006, C. tantabiddii Nolan & Cribb, 2006 from Cardicola sp. 2, Ankistromeces sp. Y from A. olsoni and Ankistromeces sp. X from Ankistromeces sp. Z. These five combinations are reinterpreted as each representing a single species; Cardicola lafii is recognised as the senior synonym of C. parilus and C. bartolii as the senior synonym of C. watsonensis. This study thus suggests that six, rather than ten, species should be recognised as infecting S. fuscescens. This richness remains greater than is known for any other fish species and siganids are, so far, unique among fishes in harbouring two strongly radiated lineages of aporocotylids.  相似文献   

5.
A new species of parasitic copepod, Caligus fajerae n. sp. (Caligidae), is described from Scomberomorus sierra Jordan & Starks (Scombridae) caught off the northwestern coast of Mexico. The new species morphologically resembles Caligus cybii Bassett-Smith, 1898, Caligus kanagurta Pillai, 1961, Caligus pelamydis Krøyer, 1863 and Caligus robustus Bassett-Smith, 1898, all of which have been reported from scombrid hosts. Caligus fajerae n. sp. differs from these species by having spinules on the abdomen and caudal ramus, two processes on the proximal antennulary segment, fine striations on the claw of the antenna and maxilliped, a stouter and more recurved maxillulary dentiform process, shorter tines on the sternal furca, two additional patches of spinules on the distal endopodal segment of leg 2, a sclerotised lobe on the anteromedian surface of the leg 3 protopod and serrations on both margins of the first exopodal spine of leg 3. Analysis of the DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 gene for Caligus fajerae n. sp. and 28 congeners, including C. pelamydis and C. robustus, showed that the new species grouped with Caligus belones Krøyer, 1863 (with 20% divergence), a species known to occur predominantly on needlefishes. Caligus fajerae n. sp. is the fifth species of Caligus reported from S. sierra. An updated host-parasite list for Caligus spp. on scombrids is provided.  相似文献   

6.
The tea red spider mite, Oligonychus coffeae Nietner is one of the major pests of tea plants in North-east India. The ladybird beetle, Stethorus aptus Kapur, is a newly reported predator of O. coffeae. Predatory efficiency study of S. aptus under laboratory conditions revealed that adult of S. aptus consumed significantly more mites than larvae. In free choice condition, the predator consumed within a range of 48–56 adults and 82–90 larvae of O. coffeae whereas the 3rd and 4th instar larvae of S. aptus consumed 20–26 adults and 50–60 larvae of O. coffeae per day respectively. Population dynamics of S. aptus was observed for 1 year under field conditions. The maximum density of the predator was recorded during January to March and it gradually declined from September onwards. Population of S. aptus showed positive correlation with its prey O. coffeae and relative humidity while effect of other factors was insignificant.  相似文献   

7.
Western skunk cabbage, Lysichiton americanus (Araceae), is pollinated mainly by the rove beetle Pelecomalium testaceum (Staphylinidae). Our objective was to determine the floral semiochemical(s) of L. americanus that attract(s) P. testaceum. Porapak Q headspace volatile extracts of L. americanus inflorescences were analyzed by gas chromatographic–electroantennographic detection (GC–EAD) and GC–mass spectrometry. In GC–EAD analyses, three floral odorants [(E)-4 nonene, (E)-5-undecene, indole] elicited consistent responses from the antennae of female P. testaceum. In field experiments, traps baited with a blend of these three components (“3-CB”) captured significantly more P. testaceum than unbaited control traps. Traps baited with the 3-CB, the two hydrocarbons, or indole, each captured significantly more beetles than unbaited control traps, indicating redundancy in the semiochemical blend. Moreover, traps baited with indole captured significantly more beetles than traps baited with either the 3-CB, or the hydrocarbons, indicating that indole is a key floral attractant for P. testaceum. Many necrophilous and coprophilous insects respond to indole in search of carrion or feces, but P. testaceum has never been associated with these types of resources. Both electrophysiological and behavioral responses of P. testaceum to two hydrocarbon semiochemicals, which are not signature odorants of carrion or feces, may indicate that the beetles recognize the odor of L. americanus as an honest signal, seek and pollinate its inflorescences, and get rewarded with pollen and on-plant mating opportunities.  相似文献   

8.
The prey preference of polyphagous predator, green lacewing (Chrysoperla zastrowi sillemi (Esben-Petersen)) was evaluated against five prey aphids viz., mustard aphid (Lipaphis erysimi), green peach aphid (Myzus persicae), cabbage aphid (Brevicorynebrassicae), black bean aphid (Aphis craccivora), spirea aphid (Aphis spiraecola) of agriculture importance and compared with eggs of Corcyracephalonica (Stainton). Lacewing larvae preferred Myzus persicae most followed by Brevicorynebrassicae. The highest growth index (8.31), larval survival (94.50 %), larval weight (10.45 mg), pupal weight (8.78 mg), faster multiplication rate (0.051) and fecundity (183.4 per gravid female) of the predator were recorded on M. persicae. However, the chrysopid reared on Corcyra eggs performed best in all biological parameters and fitness, than on aphid preys. This study explores the possibilities of selecting the most suitable prey aphid species for its exploitation as supplement for mass multiplication of chrysopid during off-season or unavailability of Corcyra eggs.  相似文献   

9.
The predation potential of a generalist predator Rhynocoris marginatus (Fab.) (Hemiptera: Reduviidae) against three important mealybug pests of cotton, Phenacoccus solenopsis Tinsley, Maconellicoccus hirsutus Green, and Coccidohystrix insolita Green (Hemiptera: Pseudococcidae) was evaluated under laboratory conditions. The specific objective of the study was to determine the prey capturing time, prey handling time, and prey preference among the three mealybug species for different developmental stages of R. marginatus. The number of prey consumed/predator/24 h by R. marginatus was dependent on the mealybug species and the predator developmental stage. Rhynocoris marginatus showed a decrease in prey capturing time and handling time as the predator grew older. After evaluating the prey stage preference, results indicated that the developmental stages of R. marginatus preferred adult mealybugs over the younger stages. In a choice-test bioassay including the three mealybug species, no significant difference in prey species selection was observed for the various R. marginatus developmental stages. However, the mortality of P. solenopsis was observed to be highest among the mealybugs, followed by M. hirsutus and C. insolita. This supports the idea that R. marginatus can be effectively utilized for the management of one of the most destructive mealybug pests of cotton, P. solenopsis. Results from this study are important for the development of a knowledge-based management program for cotton agroecosystems affected by various mealybug pests.  相似文献   

10.

Key message

We identified and cloned the two precursors of miR158 and its target gene in Brassica campestris ssp. chinensis, which both had high relative expression in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility, which was caused by the degradation of pollen contents from the binucleate microspore stage. These results first suggest the role of miR158 in pollen development of Brassica campestris ssp. chinensis.

Abstract

MicroRNAs (miRNAs) play crucial roles in many important growth and development processes both in plants and animals by regulating the expression of their target genes via mRNA cleavage or translational repression. In this study, miR158, a Brassicaceae specific miRNA, was functionally characterized with regard to its role in pollen development of non-heading Chinese cabbage (Brassica campestris ssp. chinensis). Two family members of miR158 in B. campestris, namely bra-miR158a1 and bra-miR158a2, and their target gene bra027656, which encodes a pentatricopeptide repeat (PPR) containing protein, were identified. Then, qRT-PCR analysis and GUS-reporter system revealed that both bra-miR158 and its target gene had relatively high expression levels in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility and pollen germination ratio, and the degradation of pollen contents from the binucleate microspore stage was also found in those deformed pollen grains, which led to pollen shrinking and collapse in later pollen development stage. These results first shed light on the importance of miR158 in pollen development of Brassica campestris ssp. chinensis.
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11.
The aim of this study was to evaluate the effect of farnesol on the production of acids and hydrolytic enzymes by biofilms of Streptococcus mutans and Candida albicans. The present study also evaluated the time-kill curve and the effect of farnesol on matrix composition and structure of single-species and dual-species biofilms. Farnesol, at subinhibitory concentrations, showed a significant reduction in S. mutans biofilm acid production, but did not alter C. albicans hydrolytic enzyme production. The number of cultivable cells of both microorganisms was significantly reduced after 8 h of contact with farnesol. Extracellular matrix protein content was reduced for biofilms formed in the presence of farnesol. In addition, confocal laser scanning and scanning electron microscopy displayed structural alterations in all biofilms treated with farnesol, which included reduction in viable cells and extracellular matrix. In conclusion, farnesol showed favorable properties controlling some virulence factors of S. mutans and C. albicans biofilms. These findings should stimulate further studies using this quorum-sensing molecule, combined with other drugs, to prevent or treat biofilm-associated oral diseases.  相似文献   

12.
Here, we report fossil leaves, woods, and pollen grains comparable to Calophyllum L. (mainly to Calophyllum inophyllum L. and Calophyllum polyanthum Wall. ex Choisy) of Calophyllaceae from the upper (Kimin Formation, late Pliocene-early Pleistocene), middle (Subansiri Formation, Pliocene) Siwalik sediments of the Arunachal sub-Himalaya, and lower (Gish Clay Formation of Sevok Group; middle to late Miocene) Siwalik sediments of the Darjeeling foothills, eastern Himalaya. Their presence indicates a warm and humid tropical environment in the region during the period of Siwalik sedimentation. Considering all records of Calophyllum, it is suggested that Calophyllum was a frequent forest element throughout the period of Siwalik sedimentation during the Neogene (Miocene time). At present, C. polyanthum grows in the eastern Himalaya, but C. inophyllum is totally absent from north-eastern regions suggesting differential adaptability of these taxa to changing ecoclimatic conditions. Distinct climate change in the area, possibly related to the Himalayan Orogeny during Miocene–Pleistocene times, might have caused the disappearance of C. inophyllum from the entire eastern Himalaya and north-east Indian plains and a move to littoral/coastal and swampy forests of India and other adjoining south-east Asian regions, Polynesia, and the east coast of Africa. The past global distribution of Calophyllum is also discussed, and it is suggested that India may have been its primary centre of origin. This is the first time Cenozoic fossil leaves Calophyllum siwalikum Khan, R.A.Spicer & Bera, sp. nov. comparable to C. inophyllum are described using the both macro- and micromorphological characters.  相似文献   

13.
The Azuki bean weevil, Callosobruchus chinensis (L.), is a destructive pest of stored mung bean [Vigna radiata (L.) Wilczek] as well as other leguminous seeds. The development of resistant seeds to manage this pest is of current great interest to plant breeders. In this study, we investigated the oviposition preference and development of C. chinensis on two susceptible mung bean cultivars (Seonhwa and Gyeongseon) and one previously reported resistant cultivar (Jangan), compared to the susceptible cowpea (Vigna unguiculata L.), cultivar (Yeonbun) using both multiple-choice and no-choice tests. In addition, the development of C. chinensis was also examined at four constant temperatures (20, 25, 30, and 35 °C). Both tests found cowpea to be the most suitable seed for oviposition. Total developmental time from oviposition to adult emergence ranged from 27.01 to 38.2 days, being shortest on cowpea and longest on the mung bean, cv. Jangan. However, no successful development of C. chinensis larvae on mung bean, cv. Jangan, occurred at any temperature. The highest rate of adult emergence and the longest adult longevity both occurred on cowpea and certain mung bean cultivars (Seonhwa and Gyeongseon), with the dramatic exception of cv. Jangan. These results suggest that the higher preference and performance of C. chinensis on cowpea (3.3 egg/seed) and least on mung bean, cv. Jangan (0.4 egg/seed). This information may facilitate the exploration of resistant genetic materials and chemicals associated with seeds for successful breeding. Further studies should examine the chemicals associated with mung bean cultivars and its resistant mechanism to develop a control method against bruchines.  相似文献   

14.
This study evaluated the efficacy of the foliage-dwelling predator Orius laevigatus, soil applied entomopathogens and azadirachtin alone and in combinations for controlling western flower thrips (WFT). Evaluated products were Nemastar® Steinernema carpocapsae (E-nema) and O. laevigatus (Re-natur), Metarhizium anisopliae isolate ICIPE-69 and NeemAzal-T (azadirachtin) (Trifolio). Efficacy against WFT was significantly improved by combined treatments achieving 62–97 % reduction in WFT emergence, compared to 45–74 % in single treatments, and interactions resulted in two synergistic and eight additive responses. Metarhizium-based treatments reduced WFT survival by 93–99.6 % when late mortality by mycosis was considered. Halving the number of released predators did not significantly reduce efficacy (86–96 vs. 76–88 % thrips reduction), and when Orius was introduced to target L1 of WFT, 96–98 % reduction was achieved while only 71–89 % for L2. Early release of O. laevigatus and combination with soil application of NeemAzal-T and/or entomopathogens can be a successful and reliable biocontrol strategy for WFT.  相似文献   

15.
Several species of predatory mites, especially those of the family Phytoseiidae, are potentially useful for the control of pest mites and insects. Among the phytoseiids, Euseius concordis (Chant), a species commonly found in South America, has been studied for possible use as biological control agent of pest mites. Given that Euseius species are known to feed on plant leaves and on pollen, the objective of this study was to determine plant species and pollen sources suitable to establish a pilot method of production of that species, based on a set of comparisons in the laboratory. Out of four plant species evaluated in the study, higher survivorship of E. concordis females in the absence of supplementary food was observed on leaflets of Canavalia ensiformis L. Out of two pollen types, higher survivorship was obtained on pollen of Typha domingensis L. In a subsequent step, the population of E. concordis increased 19.3× within 21 days when that pollen of T. domingensis was offered to the predator on plantlets of C. ensiformis, at 25.0 ± 1 °C, 70.0 ± 10% RH and 12 h photophase. Future studies may confirm the economic viability of this setup for the mass production of E. concordis.  相似文献   

16.
The presence and extent of hybridization within the Chenopodium album aggregate (Amaranthaceae) is still unclear. Although many hybrid combinations have been described, their existence in the field has never been systematically studied and verified. The main aim of this study was to ascertain the extent of interspecific hybridization between the diploid species C. ficifolium and C. suecicum using highly variable nuclear microsatellite markers. Due to the absence of such kind of molecular markers for the whole C. album group, we divided the analysis into two steps: (1) Eleven microsatellite loci designed for the closely related species C. quinoa were cross-amplified in five Eurasian species of the C. album diploid–polyploid complex, i.e. C. album s.s. (6x), C. striatiforme (4x), C. strictum (4x), C. ficifolium (2x) and C. suecicum (2x); (2) For the detection of interspecific hybridization between C. ficifolium and C. suecicum, we sampled 480 individuals from five localities in Central Europe. We also investigated morphological differences between the parental taxa and their hybrid and devised a key for their determination. Analysis of variation in microsatellite loci using Bayesian methods, PCoA and Neighbour-joining tree identified 32 F1 hybrids. These F1 hybrids, described here as C. paradoxum Mandák, formed a cluster between well-differentiated parental species, combining the morphological characters of both their parents. Moreover, genetic analyses also recognized several F2 or backcross hybrids, whose delimitation, mainly from C. suecicum and F1 hybrids, based on morphological characters, is problematic.  相似文献   

17.
Candida albicans is the most common human fungal pathogen and can grow as yeast or filaments, depending on the environmental conditions. The filamentous form is of particular interest because it can play a direct role in adherence and pathogenicity. Therefore, the purpose of this study was to evaluate the effects of three clinical strains of Lactobacillus on C. albicans filamentation as well as their probiotic potential in pathogen-host interactions via an experimental candidiasis model study in Galleria mellonella. We used the reference strain Candida albicans ATCC 18804 and three clinical strains of Lactobacillus: L. rhamnosus strain 5.2, L. paracasei strain 20.3, and L. fermentum strain 20.4. First, the capacity of C. albicans to form hyphae was tested in vitro through association with the Lactobacillus strains. After that, we verified the ability of these strains to attenuate experimental candidiasis in a Galleria mellonella model through a survival curve assay. Regarding the filamentation assay, a significant reduction in hyphae formation of up to 57% was observed when C. albicans was incubated in the presence of the Lactobacillus strains, compared to a control group composed of only C. albicans. In addition, when the larvae were pretreated with Lactobacillus spp. prior to C. albicans infection, the survival rate of G. mellonela increased in all experimental groups. We concluded that Lactobacillus influences the growth and expression C. albicans virulence factors, which may interfere with the pathogenicity of these microorganisms.  相似文献   

18.
The red palm mite, Raoiella indica (Acari: Tenuipalpidae), is an important pest of palms (Arecaceae) and other species within the Zingiberaceae, Musaceae and Strelitziaceae families. Raoiella indica was discovered in the USA (Palm Beach and Broward counties, Florida) late in 2007, and it subsequently spread to other Florida counties. The predatory mite Amblyseius largoensis (Acari: Phytoseiidae) has been found associated with R. indica in Florida. In order to verify whether A. largoensis can develop and reproduce when feeding exclusively on R. indica, the biology of this predator was evaluated on various food sources, including R. indica. Five diets [R. indica, Tetranychus gloveri¸ Aonidiella orientalis, Nipaecocus nipae, oak (Quercus virginiana) pollen] and a no-food control were tested to determine the predators’ development, survivorship, oviposition rate, sex ratio and longevity at 26.5 ± 1°C, 70 ± 5% RH and a 12:12 L:D photophase. Amblyseius largoensis was able to complete its life cycle and reproduce when fed exclusively on R. indica. The development of immature stages of A. largoensis was faster and fecundity and survivorship were higher when fed on R. indica or T. gloveri compared to the other food sources. The intrinsic rate of natural increase of A. largoensis was significantly higher when fed on R. indica than on other diets. These results suggest that, despite earlier assessments, A. largoensis can play a role in controlling R. indica.  相似文献   

19.
Dioscorea pseudocleistogama from the Guamuhaya Massif in central Cuba is described and illustrated. The species is assigned to Dioscorea section Rajania. It can be distinguished from other species of section Rajania by its staminate inflorescences possessing racemes of sessile to subsessile cymes bearing narrowly-tubular staminate flowers with strongly imbricate ligulate tepals, and pollen with the exine rugulate.  相似文献   

20.
Baryscapus crassicornis (Erdös) was reared from the last instar larvae of three species of Curculionidae: Larinus idoneus Gyllenhal, developing in the inflorescences of Jurinea cyanoides (L.), L. turbinatus (Gyllenhal), developing in Cirsium arvense (L.) in Russia (Ul’yanovsk Province), and L. latus (Herbst), developing in Onopordum acanthium L. and O. leptolepis DC. (Asteraceae) in Iran. Data on the parasitoid and its hosts biology, variation of morphological characters, and diagnostic notes are provided. The 3rd instar larva and the pupa of B. crassicornis are described for the first time.  相似文献   

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