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At least 19 recordsLinked to original sources
PubMed1996

Reclassification of Paenibacillus (formerly Bacillus) pulvifaciens (Nakamura 1984) Ash et al. 1994, a later subjective synonym of Paenibacillus (formerly Bacillus) larvae (White 1906) Ash et al. 1994, as a subspecies of P. larvae, with emended descriptions of P. larvae as P. larvae subsp. larvae and P. larvae subsp. pulvifaciens.

A polyphasic taxonomic study of four strains of Paenibacillus larvae and four strains of Paenibacillus pulvifaciens (including duplicates of both type strains) supported the reclassification of both former Bacillus species into one species, P. larvae. Our conclusions were based on morphological and Analytab Products (API) tests, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins, gas chromatography of methylated fatty acids, pyrolysis mass spectrometry, DNA-DNA binding, and the following genomic fingerprinting methods: amplified ribosomal DNA restriction analysis, random amplified polymorphic DNA analysis, and AFLP analysis. The last method is a novel high-resolution DNA fingerprinting technique based on the selective amplification of restriction fragments. Despite more than 90% DNA relatedness between the strains studied, SDS-PAGE of whole-cell proteins, biochemical tests, and DNA fingerprinting (AFLP) distinguished between the P. larvae and P. pulvifaciens strains at the subspecies level. Taking this evidence along with differences in pathogenicity, we propose to reclassify the honeybee pathogens P. larvae and P. pulvifaciens as P. larvae subsp. larvae and P. larvae subsp. pulvifaciens. An emended description of the species and descriptions of the subspecies are given. The type strains are P. larvae subsp. larvae ATCC 9545 (LMG 9820) and P. larvae subsp. pulvifaciens NRRL B-3685 (LMG 6911 and ATCC 13537).

Bacillus↗
PubMed2006

Reclassification of Paenibacillus larvae subsp. pulvifaciens and Paenibacillus larvae subsp. larvae as Paenibacillus larvae without subspecies differentiation.

A polyphasic taxonomic study of the two subspecies of Paenibacillus larvae, Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens, supported the reclassification of the subspecies into one species, Paenibacillus larvae, without subspecies separation. Our conclusions are based on the analysis of six reference strains of P. larvae subsp. pulvifaciens and three reference strains and 44 field isolates of P. larvae. subsp. larvae. The latter originated from brood or honey of clinically diseased honey bee colonies or from honey of both clinically diseased and asymptomatic colonies from Sweden, Finland and Germany. Colony and spore morphology, as well as the metabolism of mannitol and salicin, did not allow a clear identification of the two subspecies and SDS-PAGE of whole-cell proteins did not support the subspecies differentiation. For genomic fingerprinting, repetitive element-PCR fingerprinting using ERIC primers and PFGE of bacterial DNA were performed. The latter method is a high-resolution DNA fingerprinting method proven to be superior to most other methods for biochemical and molecular typing and has not previously been used to characterize P. larvae. ERIC-PCR identified four different genotypes, while PFGE revealed two main clusters. One cluster included most of the P. larvae subsp. larvae field isolates, as well as all P. larvae subsp. pulvifaciens reference strains. The other cluster comprised the pigmented variants of P. larvae subsp. larvae. 16S rRNA gene sequences were determined for some strains. Finally, exposure bioassays demonstrated that reference strains of P. larvae subsp. pulvifaciens were pathogenic for honey bee larvae, producing symptoms similar to reference strains of P. larvae subsp. larvae. In comparison with the type strain for P. larvae subsp. larvae, ATCC 9545T, the P. larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT100. An emended description of the species is given.

Animals↗
PubMed2004

Proposal to reclassify Paenibacillus larvae subsp. pulvifaciens DSM 3615 (ATCC 49843) as Paenibacillus larvae subsp. larvae. Results of a comparative biochemical and genetic study.

The bacterial pathogen Paenibacillus larvae subsp. larvae (P. l. larvae), is the etiological agent of American foulbrood, an extremely contagious and disastrous disease of honeybee brood. In case of American foulbrood the destruction of infected colonies is often considered the only workable control measure. Therefore, the ability to diagnose this disease properly is important to prevent unnecessary economic loss to beekeepers. The development of suitable methods for the early and reliable detection of P. l. larvae is hampered by the fact that the two subspecies of Paenibacillus larvae, P. l. larvae and Paenibacillus larvae subsp. pulvifaciens (P. l. pulvifaciens), seem to be indistinguishable by cultural characteristics as well as by PCR protocols. Here we present an extensive analysis of several P. larvae reference strains. We employed conventional culture techniques, morphological and biochemical identification, PCR-based methods and sequencing of the 16S rDNA. We found indeed that P. l. pulvifaciens strain DSM 3615 is indistinguishable from P. l. larvae (DSM 7030). We did not face any problems to discriminate between P. l. larvae and P. l. pulvifaciens strains DSM 8442 and DSM 8443. Therefore, classification of DSM 3615 as type strain of P. l. pulvifaciens seems not to be justified. We propose to reclassify this strain as P. l. larvae. Former problems in differentiating the two subspecies might have arisen from this misclassification. PCR-based methods as well as appropriate biochemical identification systems provide a reliable means for the discrimination between the two subspecies P. l. larvae and P. l. pulvifaciens.

Animals↗
PubMedDate not supplied

Studies on Trichinella spiralis. I. Concerning the time and site of insemination of females of Trichinella spiralis. II. Time of initial recovery of larvae of Trichinella spiralis from blood of experimental animals. III. Effect on the intestinal phase of trichinosis of feeding massive numbers of irradiated trichina larvae. IV. Effect of feeding irradiated Trichinella larvae on production of immunity to re-infection. V. Tests for a strain of trichina larvae resistant to radiation.

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Animals↗
PubMed2002

Differentiation of Paenibacillus larvae subsp. larvae, the cause of American foulbrood of honeybees, by using PCR and restriction fragment analysis of genes encoding 16S rRNA.

A rapid procedure for the identification of Paenibacillus larvae subsp. larvae, the causal agent of American foulbrood (AFB) disease of honeybees (Apis mellifera L.), based on PCR and restriction fragment analysis of the 16S rRNA genes (rDNA) is described. Eighty-six bacterial strains belonging to 39 species of the genera Paenibacillus, Bacillus, Brevibacillus, and Virgibacillus were characterized. Amplified rDNA was digested with seven restriction endonucleases. The combined data from restriction analysis enabled us to distinguish 35 profiles. Cluster analysis revealed that P. larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens formed a group with about 90% similarity; however, the P. larvae subsp. larvae restriction fragment length polymorphism pattern produced by endonuclease HaeIII was found to be unique and distinguishable among other closely related bacteria. This pattern was associated with DNA extracted directly from honeybee brood samples showing positive AFB clinical signs that yielded the restriction profile characteristic of P. larvae subsp. larvae, while no amplification product was obtained from healthy larvae. The method described here is particularly useful because of the short time required to carry it out and because it allows the differentiation of P. larvae subsp. larvae-infected larvae from all other species found in apiarian sources.

Animals↗
PubMed2006

Predatory activity of Rhantus sikkimensis and larvae of Toxorhynchites splendens on mosquito larvae in Darjeeling, India.

BACKGROUND AND OBJECTIVES: Predation potential of the dytiscid beetle, Rhantus sikkimensis Regimbart 1899 and the larvae of Toxorhynchites splendens Wiedemann 1819 occurring along with the larval stages of the mosquitoes in the annual lentic water bodies of Darjeeling was evaluated using the larvae of Culex quinquefasciatus Say 1823 as preys, in the laboratory under simulated natural conditions. METHODS: Field collected R. sikkimensis and larvae of Tx. splendens were offered IV instar larvae of Cx. quinquefasciatus to observe the rate of predation, at varying prey and predator densities. Based on the data obtained on the predation for a period of three consecutive days, two indices of predation, predatory impact (PI) and clearance rate (CR) values were estimated, and compared between the predator species. RESULTS: The rate of predation of IV instar Cx. quinquefasciatus larvae by R. sikkimensis ranged between 21.56 and 86.89 larvae per day, depending on the prey and predator densities. The PI value remained between 18.67 and 35.33 larvae/day depending on prey densities, while the CR ranged between 2.21 and 2.23 larvae litres/day/predator. Compared to these, the Tx. splendens larvae consumed the prey larvae at the rate of 0.67 to 34.22 larvae per day, depending on the prey and predator densities. The PI value ranged between 7.67 and 11.33 larvae/day, and the CR value ranged between 1.41 and 1.76 larvae litres/day/predator. The rate of predation, CR values and PI values of R. sikkimensis and Tx. splendens varied significantly. INTERPRETATION AND CONCLUSION: Both the predators R. sikkimensis and larvae of Tx. splendens can consume a good number of mosquito larvae, though the rate of consumption between the two predators vary owing to the difference in the life history traits and features. It can be assumed that these predators play an important role in larval population regulation of mosquitoes and thereby impart an effect on species composition and interactions in the aquatic insect communities of Darjeeling Hills, India.

Animals↗
PubMed2001

Adult honeybee's resistance against Paenibacillus larvae larvae, the causative agent of the American foulbrood.

American foulbrood is a widespread disease of honeybee larvae caused by the spore-forming bacterium Paenibacillus larvae subsp. larvae. Spores represent the infectious stage; when ingested by a larva they germinate in the midgut. The rod-shaped vegetative forms penetrate the larva's intestinal tissue and start multiplying rapidly, which finally kills the larva. Spores fed to adult honeybees, however, do not harm the bees. We investigated this phenomenon. Specifically, we studied the influence of the adult honeybee midgut on the vegetative growth and on the germination of spores of P. larvae larvae. We focused on two groups of adult workers that are likely to have large numbers of spores in their gastrointestinal tracts in infected colonies: middle-aged bees, which are known to remove or cannibalize dead larvae and clean brood cells, and winterbees, which do not have frequent chances to defecate. We found that midgut extract from winterbees and worker-aged bees of different colonies almost completely inhibited the growth of the vegetative stage of P. larvae larvae and suppressed the germination of spores. The inhibiting substance or substances from the adult midgut are very temperature stable: they still show about 60% of their growth-inhibiting capacity against this bacterium after 15 min at 125 degrees C. We established a method to test growth-inhibiting factors against P. larvae larvae in vitro.

Animals↗
PubMed2006

Dispersal strategies in sponge larvae: integrating the life history of larvae and the hydrologic component.

While known to be uniformly non-feeding, short-lived, and potentially short dispersing, sponge larvae display different behaviours (swimming ability and taxis). Our aim was to show whether sponge larvae with different behaviours exhibit different dispersal strategies under variable intensity of water movements. We first assessed the distribution of larvae of six taxa: Dictyoceratida spp., Dysidea avara, Crambe crambe, Phorbas tenacior, Scopalina lophyropoda, and Cliona viridis, collected through plankton sampling, and the abundance of the corresponding adult sponges across three hard bottom communities and a sandy bottom from a north-west Mediterranean rocky shore. We then tested adult-larvae couplings (abundance of larvae vs abundance of adults) under increasing levels of water movements (surge) to assess the importance of this environmental factor in driving differences in dispersal strategies. Adults of Dictyoceratida spp., D. avara, and P. tenacior were most abundant in semi-dark caves (SDC), C. crambe and C. viridis in communities of sciaphilic algae (SA), whereas the distribution of S. lophyropoda was extremely patchy, being present almost only in the SA community of one of the five stations studied. Larvae of Dictyoceratida spp. and P. tenacior were more abundant in the SDC, whereas D. avara and C. crambe were homogeneously distributed across the communities. The larvae of C. viridis were more abundant in the SA communities and the S. lophyropoda larvae were mostly present in one station and one community (SA). Increased water movement did not modify the adult-larvae coupling for Dictyoceratida spp., D. avara, and C. crambe, whereas it broke up the positive association for P. tenacior and to some extent S. lophyropoda. For C. viridis, possible variability in adult-larvae coupling was not tested because the larvae were collected on only one day under calm sea conditions. We confirm that efficient-swimming larvae with some cue response can actively counteract hydrodynamic forces and highlight the importance of both larval behaviour and environmental conditions in determining small-scale patterns of dispersal.

Animals↗
PubMed1996

Discovery of mammalian hosts to Gnathostoma nipponicum larvae and prevalence of the larvae in rodents and insectivores.

From September 1993 to November 1995, to clarify the natural infection of Gnathostoma nipponicum (G.n.) larvae in small wild mammals, a total of 313 animals consisted of three species of rodents and two species of insectivores, collected from an endemic area of this nematode in Aomori Prefecture, were investigated. Two species, Rattus norvegicus (R.n.) and Chimarrogale himalayica (C.h.) were infected with G.n. larvae, and the infection rate was extremely high with 27.2% and 72.7% in the former and latter. The infected animals harbored the larvae of 2-10 (mean: 6.0) in R.N. and 2-40 (10.6) in C.h., and a total of 273 larvae was recovered. The all larvae (18) from R.n. and the vast majority of the larvae (216/255: 82.4%) from C.h. were recovered from the musculature, and many encapsulated larvae were found in these portions of C.h. Taxonomically, all the larvae were identified as the advance third-stage larvae (AdL3) of G.n. The body length was 1,056-2,110 microns, and was larger than those of the naturally-infected AdL3 reported from cold-blooded animals. No morphological alterations or death of the larva was observed. From these results, it would seem that R.n. and C.h. are highly susceptible to G.n. larvae, and has very suitable characteristics as the hosts. Furthermore, a hypothesis is advanced that these mammals serves as the plausible paratenic hosts in the life cycle of G.n. This report is the first record of R.n. (Rodentia) and C.h. (Insectivora) naturally-infected with AdL3 of G.n.

Animals↗
PubMed1987

Cryopreservation of Dictyocaulus viviparus third-stage larvae and Trichinella spiralis muscle larvae.

In cryopreservation studies with third-stage larvae of Dictyocaulus viviparus, best results were achieved by incubating larvae in 0.05% NaOCl at 37 degrees C to remove the sheath, followed by cooling at a rate of 1 degree C min per min down to about 0 degree C. After an equilibration time of 10 min at +4 degrees C with or without 4% polyethylene glycol-400 as cryoprotectant, samples were frozen at the same cooling rate to an intermediate temperature of -20 degrees C, maintained at this temperature for 10 min and finally plunged into liquid nitrogen for storage. Three groups of 3 calves were infected with the following batches of third-stage larvae: (a) fresh, sheated; (b) fresh, exsheathed; (c) exsheathed, cryopreserved for 13 weeks in liquid nitrogen and subsequently thawed. Although 62% of group (c) were regarded as viable in vitro, their infectivity to calves was low and only an average of 0.08% of the inoculated larvae (3000 per animal) developed into adult lungworms (= infectivity rate). Average infectivity rates of fresh, sheathed (a) and fresh, exsheathed (b) larvae were much higher (38.3% and 29.7%) and not significantly different from each other. Two of the calves inoculated with previously frozen larvae and all of the calves infected with fresh larvae excreted first-stage larvae in their faeces, but the latter groups in higher quantities. The results show that cryopreservation of exsheathed third-stage larvae of D. viviparus is possible, but for strain maintenance infection doses greater than 3000 larvae should be used for inoculation of calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

A PCR-based method that permits specific detection of Paenibacillus larvae subsp. larvae, the cause of American Foulbrood of honey bees, at the subspecies level.

AIMS: A reliable procedure for the identification of Paenibacillus larvae subsp. larvae, the causal agent of American Foulbrood disease of honey bees (Apis mellifera L.) based on the polymerase chain reaction (PCR) and subspecies - specific primers is described. METHODS AND RESULTS: By using ERIC-PCR, an amplicon of ca 970 bp was found among P. l. larvae strains but not in other closely related species. Based on the nucleotide sequence data of this amplicon, we designed the pair of oligonucleotides KAT 1 and KAT 2, which were assayed as primers in a PCR reaction. A PCR amplicon of the expected size ca 550 bp was only found in P. l. larvae strains. CONCLUSIONS: This PCR assay provides a specific detection for P. l. larvae. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed PCR assay is highly specific because can differentiate Paenibacillus larvae subsp. larvae from the closely related Paenibacillus larvae subsp. pulvifaciens. The technique can be directly used to detect presence or absence of P. l. larvae spores in honey bee brood samples and contaminated honeys.

Animals↗
PubMed1996

A survey of Gnathostoma larvae in fresh water fish in the valley of the Yangtze River and morphological characteristics of the recovered larvae.

Investigations of the prevalence of larval gnathostomes in fresh water fishes were carried out at the southeastern Yangtze Valley, People's Republic of China, in the periods of October 1989 and November 1990. Fishes were collected from Shanghai, Chenchiang, Nanching, Chiuchiang and Nanchang districts in 1989. Additional sampling in Shanghai district was done at Kunshan, Tien-shanfu, Chingpu and Nanhui. Species of fishes collected were Channa argus (110), Siniperca chuatsi (24) and Silurus asotus (2). Muscle tissue of the fishes was dissected into small pieces, sliced and then examined under a dissecting microscope. The viscera were pooled by species in groups of 4 or 5 individuals, homogenized, and were then digested overnight in artificial gastric-juice at 37 degrees C. Four encysted larvae were recovered from the muscle tissue of four C. argus. Thirty-four larvae were obtained from digestion of viscera. A total of 38 larvae were recovered. Eighteen of 38 larvae were examined morphologically and they were able to be divided into three types by their body length; 5 early third-stage larvae (0.58-0.86 mm), 12 third-stage larvae (1.12-2.61 mm), and one advanced third-stage larva of 4.86 mm. Light and scanning electron microscopy revealed that the former two types had characteristics of Gnathostoma hispidum and the last one had those of G. spinigerum. In 1990, we investigated fish near Hongtze-hu and Tai-hu lakes. A total of 553 fishes belonging to 12 genera and 12 species were examined. Seventeen larvae were recovered from the viscera of G. argus and Monopterus albus. These larvae were identified as G. hispidum.

Animals↗
PubMed2000

Histochemical characterization of cell death in honeybee larvae midgut after treatment with Paenibacillus larvae, Amitraz and Oxytetracycline.

A number of techniques were employed to assess cell death induced in honeybee larvae midgut after per os inoculation of bacterium Paenibacillus larvae var. larvae, the causative agent of American foulbrood disease, and separately with acaricide Amitraz and antibiotic Oxytetracycline. In honeybee larvae exposed to Amitraz, which demonstrates both necrosis and apoptosis, cell death was found in 82% of midgut columnar and in 50% of regenerative epithelial cells, 24 h after treatment. Cell death reduced to 36% in the epithelial cells, 48 h after treatment. In Oxytetracycline-treated larvae, cell death was identified in 40% of midgut epithelial cells, 24 h after inoculation and increased to 55% over the next 24 h. In Paenibacillus -infected larvae, all midgut epithelial cells died. Using ApopTag (Oncor) to label the multiple DNA ends generated by DNA fragmentation showed programmed cell death in 49% of columnar midgut cells 24 h after Amitraz application. Cell death was reduced to 9% over the next 24 h. Our data indicate that cell death could be identified and quantified in situ, using TUNEL techniques. This study also shows that the acaricide Amitraz is a trigger for programmed cell death in the midgut epithelial cells of honeybee larvae, unlike Paenibacillus which induces necrosis only. The data show that immunohistochemical methods are useful for studying in situ tissue pathology, and indicate possibilities for monitoring the effects of infective and chemical environmental stressors on cell death in honeybee larvae tissue.

Adrenergic alpha-Agonists↗
PubMed2004

Carabid larvae as predators of weed seeds: granivory in larvae of Amara eurynota (Coleoptera: Carabidae).

Up to date we do not have much information about predation on seeds by larvae of ground beetles. One of the reasons why such knowledge is important is that granivorous larvae contribute to predation of weed seeds. In this study, the food requirements of larvae of autumn breeding carabid species Amara eurynota (Panzer) were investigated in the laboratory and a hypothesis, that they are granivorous was tested. Insect diet (Tenebrio molitor larvae), three seed diets (seeds of Artemisia vulgaris, Tripleurospermum inodorum or Urtica dioica or a mixed diet (T. molitor + A. uulgaris) were used as food. For larvae of A. eurynota, seeds are essential for successful completion of development, because all those fed pure insect diet died before pupation. However, differences in suitability were observed between pure seed diets. Larvae fed seeds of A. vulgaris had the lowest mortality and fastest development of the seed diets. Those fed seeds of T. inodorum had also low mortality, but the development was prolonged in the third instar. In contrast, development of larvae reared on seeds of U. dioica was slowest of the tested diets and could not be completed, as all individuals died before pupation. When insects were included to seed diet of A. vulgaris (mixed diet), the duration of development shortened, but mortality remained the same when compared to seed diet of A. vulgaris. According to the results it was concluded that larvae of A. eurynota are granivorous. A mixed diet and seed diets of A. uulgaris and T. inodorum were suitable and insect diet and seeds of U. dioica were unsuitable diets in this experiment.

Animals↗
PubMed2001

Effects of juvenile hormones and precocenes on the immune response of Spodoptera littoralis larvae to supernumerary larvae of the solitary parasitoid, Microplitis rufiventris Kok.

The study represents one of the first direct tests of juvenile hormones (JHs) on the cellular immune response of a lepidopteran insect, Spodoptera littoralis (Boisd.), superparasitized by a solitary parasitoid, Microplitis rufiventris Kok. JHII-treated S. littoralis larvae exhibited a significant reduction in encapsulation response to the supernumerary M. rufiventris larvae at different developmental ages (0-4, 10-14 and 24-26 h) of supernumerary M. rufiventris embryos within 48 or 144 h after parasitization than either JHI-treated or control hosts. The reduction in encapsulation response was significantly greater in hosts which received higher JHII dose (5 &mgr;g) than those treated with lower one (1 &mgr;g).The progression of the encapsulation, culminating in melanization in the capsules occurred more frequently in precocene-treated hosts than either JH-treatment or control ones. Application of the anti-juvenile hormones (PI or PII) caused stronger encapsulation reaction to the injured supernumerary parasitoid larvae than JHI or JHII. In PI-treatments, the reaction was rapid and dramatic by lower (25 &mgr;g) dose treatments than higher ones (70 &mgr;g).The capsules formed around the supernumerary larvae of M. rufiventris showed signs of melanization within 48 h in PI-treated hosts. Melanization was more pronounced in either PI- or PII-treated hosts prior emergence of successful parasitoid larvae. Generally, the injured supernumerary larvae were seen within melanin-rich capsules in PI- and PII-treated hosts. Melanization was not observed in most capsules of JHI- and JHII-treated hosts. Additional physiological effects were observed: (1) in some cases, application of JHI to parasitized S. littoralis larvae inhibited subsequent emergence of its wasp, M. rufiventris, and (2) teratocytes (cells of wasp origin) from PI or PII-treated hosts were smaller in size than those observed in the JH-treated or control hosts.Finally, the dramatic increase in encapsulation responses of precocene-treated S. littoralis larvae of the supernumerary of M. rufiventris and definitely opposite reactions in typical hosts but JHII-treated hosts suggested that the cellular defense reaction may be under inhibitory hormonal control.The results of the study have implications for medically important insects such as mosquitoes and their interactions with parasites, as well as having significance for biocontrol and mass rearing programs using parasitoids.

Journal Article↗