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1.
Surface inoculation dose–response and time–response bioassays and detached fruit bioassays were conducted with a novel South
African isolate of the Cryptophlebia leucotreta granulovirus (CrleGV-SA) against Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Noctuidae) neonate larvae. LC50 and LC90 values were estimated to be 4.095 × 103 and 1.185 × 105 OBs ml−1, respectively. LT50 and LT90 values were estimated to be 4 days 22 h and 7 days 8 h, respectively, categorising the virus as a fast or type 2 granulovirus.
There was a conspicuous difference in behaviour between larvae on inoculated diet and untreated diet, resulting in a significant
reduction in penetration of diet. Bioassays on detached Navel oranges revealed LC50 and LC90 values of 9.310 × 107 and 1.515 × 109 OBs ml−1, when using data on numbers of larvae per fruit rather than on numbers of infested fruit. Field trials will be conducted. 相似文献
2.
Here we describe the establishment of a new cell line, NTU-MV, derived from pupal tissues of an economically important pest, the legume pod borer Maruca vitrata. This cell line contained four major cell types: polymorphic cells, round cells, spindle-shaped cells, and comma cells. The doubling time of MV cells in TNM-FH medium supplemented with 8% FBS at 28 degrees C was 27h. The chromosome numbers of MV cells varied widely from 16 to 268. Compared to other insect cell lines, the MV cell line produced distinct isozyme patterns with esterase, malate dehydrogenase (MDH), and lactate dehydrogenase (LDH). Confirmation that NTU-MV was derived from M. vitrata was demonstrated by showing that the sequence of the internal transcribed spacer regions (ITS) of the MV cells was 98% identical to that of M. vitrata larvae. Two NTU-MV cell strains, NTU-MV1 and NTU-MV56, were selected based on susceptibility to MaviMNPV (M. vitrata multiple nucleopolyhedrovirus). NTU-MV, MV1, and MV56 cells showed a high susceptibility to MaviMNPV and produced high yields of polyhedra (47-50OBs/cell, 4x10(7)-5.96x10(7)OBs/ml) after 2 weeks of MaviMNPV infection. We conclude that the NTU-MV cell line will be a useful tool for studying MaviMNPV as well as for the mass production of MaviMNPV polyhedra for the biocontrol of M. vitrata. 相似文献
3.
Effect of eight benthic diatoms as feed on the growth of red abalone (Haliotis rufescens) postlarvae 总被引:1,自引:0,他引:1
Juan Gabriel Correa-Reyes María del Pilar Sánchez-Saavedra María Teresa Viana Norberto Flores-Acevedo Carlos Vásquez-Peláez 《Journal of applied phycology》2009,21(4):387-393
The growth rate of abalone post larvae of Haliotis rufescens fed ad libitum with a benthic monoalgal diatom culture maintained as monocultures on a semi-commercial scale, was evaluated
and correlated with the biochemical composition of the diatoms. The cell size (7.0 × 4.0 μm to 21.0 × 7.5 μm), protein percentage
(7.42% to 13.66%), and ash content (49.03% to 59.61%) were different among diatom strains; lipid percentage, nitrogen free
extract, and energy content (Kcal g−1) were similar among diatom strains. The values of essential and non-essential amino and fatty acids composition differed
among diatom strains. Differences in the abalone shell length and orthogonal analyses revealed postlarval growth was dependent
on the quality of the food source. Postlarvae abalone displaying the longest shell lengths were fed Nitzschia thermalis var. minor and Amphiprora paludosa var. hyalina (1,712.0 ± 61 μm and 1,709 ± 67 μm, respectively), followed by Navicula incerta (1,413.3 ± 43 μm). The fatty acid content of benthic diatoms and abalone growth rate were not correlated. 相似文献
4.
Different pH control agents (NaOH/H2SO4—SodSulp, NaOH/CH3COOH—SodAcet, NH4OH/CH3COOH—AmmoAcet and NH4OH/H2SO4—AmmoSulp) were used to investigate their effects on growth, enzyme production (alkaline protease and amylase), and entomotoxicity
of Bacillus thuringiensis var. kurstaki HD-1 (Btk) against eastern spruce budworm larvae (Choristoneura fumiferana) using starch industry wastewater (SIW) as a raw material in a 15-l fermentor. AmmoSulp and SodSulp were found to be the
best pH control agents for alkaline protease and amylase production, respectively; whereas, the fermented broth obtained by
using SodAcet as pH control agents recorded the highest delta-endotoxin production of 1043.0 mg/l and entomotoxicity value
18.4 × 109 SBU/l. Entomotoxicity of re-suspended centrifuged pellet in one-tenth of original volume in case of SodAcet as pH control
agents was 26.7 × 109 SBU/l and was the highest value compared to three other pH control agents. 相似文献
5.
We studied the response of Brachionus patulus to different concentrations of the heavy metal Pb in the presence and absence of sediments. We conducted acute (LC50) and chronic (life table demography and population growth) toxicity tests using sediment levels of 0, 30 and 280 mg l−1 (=0, 17 and 170 NTU) and Pb at 0, 0.06 and 0.6 mg l−1. Experiments were conducted at 20 ± 1°C on a horizontal shaker and algal food (Chlorella vulgaris) was added at a density of 1.0 × 106 cells ml−1. The median lethal concentration (LC50 ± 95% Confidence intervals) of PbCl2 for B. patulus was 6.15 ± 1.08 mg l−1. Age-specific survivorship and fecundity curves showed increase in turbidity level resulted in decreased survival and offspring
production of the rotifers. Increase in Pb concentration too had a negative effect on the survival and reproductive output
of B. patulus. Statistically, average lifespan, life expectancy at birth, gross and net reproductive rates and the rate of population increase
were all significantly influenced by the concentration of Pb, turbidity level as well as the interaction of Pb concentration × turbidity
level. Rotifers exposed to 170 NTU did not grow regardless of the heavy metal concentration in the medium. Similarly, B. patulus exposed to 0.6 mg l−1 Pb did not survive beyond 10 days regardless of the turbidity level in the medium. The rate of population increase of B. patulus derived from the growth experiments was negative in all treatments containing Pb as low as 0.06 mg l−1 or turbidity level as low as 17 NTU. In treatments containing Pb or sediments, there existed no relation between the egg
ratio and the population density.
Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont and R. Rico-Martínez
Advances in Rotifer Research 相似文献
6.
Khasdan V Sapojnik M Zaritsky A Horowitz AR Boussiba S Rippa M Manasherob R Ben-Dov E 《Archives of microbiology》2007,188(6):643-653
The genes cry1Ac and cry1Ca from Bacillus thuringiensis subsps. kurstaki HD-73 and aizawai 4J4, respectively, encoding δ-endotoxins against lepidopteran larvae were isolated, cloned and expressed in Escherichia coli, with and without cyt1Aa (encoding cytolytic protein) and p20 (accessory protein) from subsp. israelensis. Nine combinations of the genes under control of an early T7, P
A1
inducible promoter, produced the encoding proteins. Toxicities were examined against larvae of three major agricultural pests:
Pectinophora gossypiella, Helicoverpa armigera and Spodoptera littoralis. The clones expressing cyt1Aa, with or without p20, were not toxic. The clone expressing cry1Ac (pBt-1A) was the most toxic to P. gossypiella (LC50 of 0.27 × 108 cells g−1). Clone pBt-1CA expressing cry1Ca and cry1Ac displayed the highest toxicity (LC50 of 0.12 × 108 cells ml−1) against S. littoralis. Clone pBt-1CARCy expressing all four genes (cry1Ca, cry1Ac, p20, cyt1Aa) in tandem exhibited the highest toxicity to H. armigera (LC50 of 0.16 × 108 cells ml−1). Cyt1Aa failed to raise the toxicity of these Cry toxins against P. gossypiella and S. littoralis but significantly enhanced toxicity against H. armigera. Two additional clones expressing either cry1Ac or cry1Ca under tandem promoters, P
A1
and P
psbA
(constitutive), displayed significantly higher toxicities (7.5- to 140-fold) than their counterparts with P
A1
alone, reducing the LC50 values to below 107 cells ml−1.
Vadim Khasdan and Maria Sapojnik are contributed equally to this work. 相似文献
7.
Thomas R. Unruh Lawrence A. Lacey Heather L. Headrick Robert S. Pfannenstiel 《Biocontrol Science and Technology》2012,22(9):981-990
An indigenous betabaculovirus (PapyGV) of the Pandemis leafroller, Pandemis pyrusana (Kearfott), was studied in the laboratory and greenhouse to determine how the virus affected leafroller mortality and foliar damage. Probability of mortality increased with virus concentration as observed after 7 and 10 days of feeding on virus treated diet in neonates and second instar larvae. LC50 estimates for neonates at 7 and 10 days was 2743 and 389 occlusion bodies (OBs)/mm2. For second instars, LC50 was 139,487 and 813 OBs/mm2 at 7 and 10 days. There was no biologically significant mortality response to increasing virus concentrations by fourth instar larvae; however, when fourth instar larvae were infected with virus on diet and then fed apple leaves, the leaf area consumed declined up to 50% with higher virus concentrations. In a greenhouse study, neonate larvae that fed on seedlings treated with water showed >90% survival and 80% pupation rate of larvae after being transferred to diet. In contrast, larvae that fed on apple seedlings sprayed with 3×106 OBs/ml showed poor survival when transferred to diet after acquiring the virus and failed to reach the pupal stage. This virus shows promise for population regulation and can produce reduction in feeding damage. 相似文献
8.
Colleen R. Alma Mark S. Goettel Bernard D. Roitberg David R. Gillespie 《BioControl》2007,52(5):669-681
The effects of intraguild interactions between Dicyphus hesperus Knight (Hemiptera: Miridae) and Paecilomyces fumosoroseus Apopka-97 (PFR-97TM) (Wize) Brown and Smith (Ascomycota: Hypocreales) on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) populations were investigated in tomato greenhouse microcosms. Conditions were established
in which interference or synergy would most likely occur; namely, a high number of available whiteflies were combined with
large numbers of both D. hesperus and PFR-97TM. We measured live whitefly density in a factorial repeated measures experiment where plants were provided or withheld releases
of D. hesperus and/or applications of PFR-97TM for 6 weeks. Releases of D. hesperus were made at a rate of 10 adults/plant during the first and third week and PFR-97TM suspensions were applied with a backpack sprayer at a rate of 18 × 107, 1.3 × 107 and 1.2 × 107 viable blastospores/ml during the first, third and fourth week, respectively. Results revealed a non-significant interaction
effect between D. hesperus and PFR-97TM, indicating that their actions were independent. Individual whitefly reductions of 48% and 35% were achieved by PFR-97TM and D. hesperus, respectively. Collectively, the natural enemies reduced whitefly densities by 62% relative to the controls. The density
of D. hesperus adults was unaffected by multiple applications of PFR-97TM. These results suggest that the combination of generalist entomopathogenic fungi and generalist predators has the potential
to cause increased pest mortality despite evidence of minimal interference. 相似文献
9.
The susceptibility of larvae of the leek moth, Acrolepiopsis assectella Zeller (Lepidoptera: Acrolepiidae) to different concentrations of an autochthonous strain of Steinernema feltiae (Rhabditida: Steinernematidae) was examined in laboratory experiments using Petri dishes. The efficacy of this strain in
pots and field experiments was also evaluated. High mortality (80%–100%) of leek moth larvae was observed when these larvae
were exposed to low concentrations (3 × 103 to 1 × 104 IJs/m2) of S. feltiae under laboratory conditions. Foliar application of 30,000 IJs/leek in pot experiments caused a 98% reduction in leek moth
larvae. Field experiments showed a 87.7% reduction of leek moth larvae with the nematode treatment, significantly higher than
the 22% reduction with the Bacillus thuringiensis treatment. The efficacy of the treatments with S. feltiae in relation to the microhabitat of the leek moth larvae between the interfolded leaves of the leek is discussed. 相似文献
10.
Magali Ordóñez-García Claudio Rios-Velasco José de Jesús Ornelas-Paz Juan Carlos Bustillos-Rodríguez Carlos Horacio Acosta-Muñiz David Ignacio Berlanga-Reyes Miguel Ángel Salas-Marina Octavio Jhonathan Cambero-Campos Gabriel Gallegos-Morales 《Journal of Applied Entomology》2020,144(1-2):123-132
The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is the most important pest of maize in many countries. Entomopathogenic viruses mainly Baculoviruses family are excellent biological control agents and therefore a viable alternative for managing this pest. The aim of this study was to determine the biological activity of eight native nucleopolyhedrovirus (NPVs) against FAW larvae. Additionally, two of the most virulent isolates (SfCH32 and SfCH15) were characterized biologically by bioassays to estimate their median lethal dose (LD50) and median lethal time (LT50), morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and molecularly by restriction enzymes. Three (SfCH15, SfCH18 and SfCH32) of the eight tested native nucleopolyhedrovirus isolates caused mortalities ˃98% at 168-hr post-inoculation (hpi) with a dose of 9.2 × 104 OBs/larva. SfCH15 and SfCH32 isolates showed occlusion bodies (OBs) of irregular shape and size (1.02–2.24 μm). The SfCH15 and SfCH32 isolates showed similar median lethal dose (5.6 × 102–6.4 × 102 OBs/larva). The lowest median lethal time (114.5 hpi) was observed with the SfCH15 isolate at the highest concentration (2.5 × 106 OBs/larva). The DNA restriction profiles for SfCH15 and SfCH32 were different, with their genome size being ~128,000 bp and 132,000 bp, respectively. SfCH15 and SfCH32 isolates showed similar morphological characteristics and the highest virulence against fall armyworm. This study showed that native isolates were highly virulent against S. frugiperda larvae, being similar to other reported strains; however, field studies are required to confirm their insecticidal effect. 相似文献
11.
Ribitsch D Karl W Wehrschütz-Sigl E Tutz S Remler P Weber HJ Gruber K Stehr R Bessler C Hoven N Sauter K Maurer KH Schwab H 《Applied microbiology and biotechnology》2009,81(5):875-886
In the course of a microbial screening of soil samples for new oxidases, different enrichment strategies were carried out.
With choline as the only carbon source, a microorganism was isolated and identified as Arthrobacter nicotianae. From this strain, a gene coding for a choline oxidase was isolated from chromosomal DNA. This gene named codA was cloned in Escherichia coli BL21-Gold and the protein (An_CodA) heterologously overexpressed as a soluble intracellular protein of 59.1 kDa. Basic biochemical characterization of
purified protein revealed a pH optimum of 7.4 and activity over a broad temperature range (15–70 °C). Specific activities
were determined toward choline chloride (4.70 ± 0.12 U/mg) and the synthetic analogs bis(2-hydroxyethyl)-dimethylammonium
chloride (0.05 ± 0.45 × 10–2 U/mg) and tris-(2-hydroxyethyl)-methylammonium methylsulfate (0.01 ± 0.12 × 10–2 U/mg). With increasing number of oxidizable groups, a significant decrease in activity was noted. Determination of kinetic
parameters in atmorspheric oxygen resulted in K
M = 1.51 ± 0.09 mM and V
max = 42.73 ± 0.42 mU/min for choline chloride and K
M = 4.77 ± 0.76 mM and V
max = 48.40 ± 2.88 mU/min for the reaction intermediate betaine aldehyde respectively. Nuclear magnetic resonance spectroscopic
analysis of the products formed during the enzyme reaction with choline chloride showed that in vitro the intermediate betaine
aldehyde exists also free in solution. 相似文献
12.
Williams JB Lee RE 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(3):365-375
Possible links between cold-tolerance and desiccation resistance were examined between larvae of the goldenrod gall fly collected
from Michigan, southern Ohio, and Alabama locations as their host plant senesced. After acclimation to 5°C, Michigan-collected
larvae were more cold-tolerant (25% survival after a 96 h exposure to −40°C) than larvae from Ohio (10% survival) and Alabama
(0% survival). Increased cold-tolerance was partially linked to higher concentrations of the cryoprotectant glycerol (Michigan:
500 ± 30 mmol; Ohio: 270 ± 20; Alabama: 220 ± 20). Moreover, cryoprotectants may have functioned to reduce rates of overall
and cuticular water loss for Michigan larvae, 0.10 ± 0.01 and 0.037 ± 0.003 μg mm−2 h−1, respectively, values that were 40-44% lower than those for Ohio and Alabama larvae and may represent a link between desiccation
resistance and cold-tolerance. After acclimation to 20°C, Alabama-collected larvae had metabolic rates that were 40% lower
than those from Ohio and Michigan that averaged 0.100 ± 0.006 μl of CO2 produced g−1 h−1. The lower metabolic rate of Alabama-collected larvae at 20°C likely resulted in reduced respiratory transpiration that may
represent a mechanism to maintain water balance at the higher overwintering temperatures they typically experience. 相似文献
13.
K. Sangthongpitag R. J. Penfold S. F. Delaney P. L. Rogers 《Applied microbiology and biotechnology》1997,47(4):379-384
Genes encoding the mosquitocidal binary toxin of Bacillus sphaericus 2362 were introduced into Synechococcus PCC6301, a cyanobacterium that can tolerate a number of potential variations in the mosquito breeding environment, and can
serve as a food source for mosquito larvae. The toxin genes, preceded by a Synechococcus rbcL promoter, were located on a mobilizable Escherichia coli Synechococcus shuttle vector, which was introduced into Synechococcus PCC6301 at frequencies of 10−5–10−7 exconjugants/recipient, depending on the selective conditions used. Recombinant Synechococcus exhibited significant toxicity against 2-day-old and 6-day-old Culex quinquefasciatus larvae, the concentration required to kill 50 % of larvae (LC50) being 2.1 × 105 and 1.3 × 105 cells/ml respectively. Mosquitocidal activity decreased tenfold after 20 generations of non-selective growth.
Received: 23 July 1996 / Received revision: 11 November 1996 / Accepted: 15 November 1996 相似文献
14.
In the first part of this study, four isolates of the fungus Beauveria bassiana (Bals.) Vuillemin (LPP1, LPP2, CG05 and CG24) and one isolate of Metarhizium anisopliae (Metsch.) Sorokin (CG46) were tested against adult foragers of Atta sexdens rubropilosa. Ants were allowed to walk on filter paper discs, inside Petri dishes, previously impregnated with 1 ml of a conidia suspension
(2 × 107 conidia ml−1), maintained at 80% RH and 26°C for 24 h and subsequently, transferred to sterile Petri dishes, maintained at 23°C, 80% RH,
24 h dark. The mean values of LT50 for LPP2, LPP1, CG46, CG24 and CG05 were 3.5, 3.7, 3.8, 4.2 and 4.4 days, respectively. Control insects for all tests in
this study showed less than 10% mortality. Experiments were carried out to test the toxicity of imidacloprid (IMI) to A. sexdens rubropilosa. Mortality was evaluated 10 days following a 24 h exposure to the insecticide. Percent mortality caused by 500, 200, 100
and 10 ppm IMI was 77.8, 56.7, 45.5 and 5.5 respectively. Insects treated with 10 ppm IMI were observed to have reduced locomotor
activity 24 h after exposure to the insecticide. The LC50 of IMI was 154.3 ppm. Subsequent tests were carried out to evaluate the combination of a sub-lethal dose of IMI (10 ppm)
and infection by CG24 (1 × 107 conidia ml−1). Mortality due to fungal infection alone was 43.3%. Mortality of insects treated with IMI followed by exposure to the fungus
was 64.3%. These results indicate that IMI significantly increases the susceptibility of ants to infection by B. bassiana CG24. 相似文献
15.
Gabriel Moura Mascarin Sérgio Batista Alves Fátima Teresinha Rampelotti-Ferreira Mariana Ragassi Urbano Clarice Garcia Borges Demétrio Italo DelaliberaJr. 《BioControl》2010,55(5):657-671
In this study a Brazilian granulovirus strain, PhopGV, isolated from the potato tuber moth (PTM) Phthorimaea operculella, was investigated regarding its potential for biological control and in vivo production. The relationship between mortality
of P. operculella larvae and virus concentration was determined at different temperatures on potato tubers and susceptibility of P. operculella to PhopGV was also determined on potato leaves. Virulence of PhopGV to P. operculella was not affected by temperatures from 18 to 30°C. The median lethal concentration (LC50) of larvae fed on potato foliage treated with PhopGV was not higher than that verified with larvae fed on treated tubers.
Optimal conditions for production of virus-infected larvae were obtained by using the virus suspensions of 41 × 105, 6.3 × 105 and 62 × 105 OBs ml−1 at 18, 24 and 30°C, which resulted in 32.0, 31.4 and 34.8% of infected larvae collected, respectively. The maximum percentage
of infected larvae recovered from tubers was not affected by temperature. However, time for production of virus-infected larvae
was longer at 18°C and shorter at 30°C. Persistence of PhopGV was determined on stored tubers and we observed that the virus
remained effective for at least two months, causing up to 84.2% mortality of P. operculella at 1 × 107 OBs ml−1. The pathogen was also highly virulent to tomato pinworm, Tuta absoluta, inflicting high percentage of mortality, delaying larval growth and inhibiting pupation. This Brazilian PhopGV strain has
potential to control PTM larvae on potato tubers at a broad range of temperature and can be produced in vivo using virus-treated
tubers. 相似文献
16.
Fawzeia H. Elmhalli Katinka Pålsson Jan Örberg Thomas G. T. Jaenson 《Experimental & applied acarology》2009,48(3):251-262
The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs
at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate
increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results
obtained by methods A, C and E, the LC50 range was 0.035–0.037 mg PMD/cm2 and the LC95 range was 0.095–0.097 mg PMD/cm2 at 4 h of exposure; the LT50 range was 2.1–2.8 h and the LT95 range was 3.9–4.2 h at 0.1 mg PMD/cm2. To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm2) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed
that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic
to nymphs of I. ricinus and may be useful for tick control. 相似文献
17.
The insecticidal effect of Mamestra brassicae nucleopolyhedrovirus (MabrNPV) and the enhancing activity of proteins derived from occlusion bodies (OBs) of Xestia c-nigrum granulovirus (GVPs) on the infectivity of MabrNPV were evaluated in a bioassay with second-instar larvae of Autographa nigrisigna (Walker) fed virus-applied cabbage plants. The lethal concentrations of MabrNPV achieving 50 and 95% mortality for A. nigrisigna were estimated to be 1.4 × 105 and 3.1 × 106 OBs/ml, respectively. When larvae were fed cabbage plants treated with MabrNPV and various concentrations of GVPs, the requisite
concentration of GVPs achieving 95% mortality of A. nigrisigna was estimated to be 26.2–138.8 μg/ml in combination with 104 OBs/ml MabrNPV and 8.46–24.09 μg/ml with 105 OBs/ml MabrNPV. Increases in the concentration of MabrNPV or GVPs caused larval death at younger instars. A. nigrisigna has lower susceptibility to MabrNPV than M. brassicae and Helicoverpa armigera reported in Mukawa and Goto (J Econ Entomol 103:257–264, 2010). We estimated that the requisite concentration of MabrNPV for the control of A. nigrisigna was 105 OBs/ml, which is a tenfold higher concentration than that for M. brassicae and H. armigera, with the increase achieved by adding 10 μg/ml GVPs. 相似文献
18.
To develop an integrated process of CO2-fixation and H2 photoproduction by marine green microalga Platymonas subcordiformis, the impact of algal cells grown in CO2-supplemented air bubble column bioreactor was investigated on H2 photoproduction regulated by carbonylcyanide m-chlorophenylhrazone. Highest cell growth (3.85 × 106 cells ml−1), starch content (0.25 ± 0.08 mg per 106 cells) and hydrogen production (50 ± 3 ml l−1) were achieved at 3% CO2-supplemented culture, which are respectively 1.4, 2.1, 1.5-fold of the air-supplemented culture. Improved H2 production correlated well with the increase in starch accumulation. In this process, the algal cells have been recycled
for stable H2 production of 40–50 ml l−1 over five cycles. 相似文献
19.
Agbeko Kodjo Tounou Christiann Kooyman Ouro Kobi Douro-Kpindou Hans Michael Poehling 《BioControl》2008,53(5):813-828
Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was
done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%.
Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density
over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection
level of 6.2 ± 0.8 × 106, 2.3 ± 0.3 × 104 and 2.1 ± 0.3 × 103 spores mg−1 host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs. 相似文献
20.
J. Eleazar Barboza-Corona Tomás Ortiz-Rodríguez Norma de la Fuente-Salcido Dennis K. Bideshi Jorge E. Ibarra Rubén Salcedo-Hernández 《Antonie van Leeuwenhoek》2009,96(1):31-42
Bacillus thuringiensis HD-73 was transformed with the endochitinase gene chiA74 under the control of a strong promoter (pcytA) and a 5′ mRNA stabilizing (STAB-SD) sequence (HD-73-pEBchiA74). Expression levels were compared with those observed from
the wild type strain (HD-73) and the recombinant HD-73 strain expressing chiA74 under the control of its native promoter (HD-73-pEHchiA74). The chitinolytic activity of HD-73-pEBchiA74 was markedly elevated,
being ~58- and 362-fold higher than, respectively, HD-73-pEHchiA74 and parental HD-73, representing the highest levels of
chitinase expression in recombinant B. thuringiensis reported to date. Parasporal crystals measured under transmission electron microscopy showed that HD-73 produced crystals
of 1.235 (±0.214) and 1.356 (±0.247) μm in length when the bacterium was grown in respectively, NBS and NBS with glucose.
Otherwise, HD-73-pEBchiA74 synthesized crystals of 1.250 (±0.222) and 1.139 (±0.202) μm in length when cultivated in NBS and
NBS with glucose, respectively, values that showed a diminution of ~10 and 20% compared with crystals produced by HD-73-pEHchiA74
grown under the same conditions. Comparison of viable spore counts per ml showed that HD-73-pEBchiA74 produced fewest viable
spores (1.5 × 109, 1.3 × 109), compared to HD-73-pEHchiA74 (4.9 × 109, 5.3 × 109) and HD-73 (6.8 × 109, 8.8 × 109) when grown in NBS and NBS supplemented with glucose, respectively. No change in cellular protease activity was observed
despite the overproduction of the chitinase. 相似文献