Effect of Six Bacterial Strains on the Activity of Second Instar Larvae and Egg Hatching of Meloidogyne incognita

[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita.

Nondestructive detection of infertile hatching eggs based on spectral and imaging information

In order to quickly distinguish infertile eggs from fertile eggs,the hyperspectral imaging technology consisting of imaging and spectral information was used for detecting the fertile information of eggs.Before hatching eggs were incubated,a hyperspectral imaging system(wavelength between 400 to 1000 nm)was used to acquire the images one-by-one manually.The characteristic information of ratios of length to short axis,elongation,roundness and the ratios of the yolk area to the whole area was extracted based on the images.The normalization method was used as the spectral data preprocessing,and then 155 spectral characteristic variables were extracted from 520 nm waveband through the correlation coefficient method.Principal component analysis(PCA)method was adopted to reduce the dimensions of image-spectrum fusion information;the top six principal components were extracted.Support vector machine(SVM)method was used to establish classification of fertile and infertile eggs models,which are based on image,spectrum and image-spectrum fusion information respectively.The accuracy rates of the SVM models were 84.00%,90.00%and 93.00%respectively.The experimental results show that the model based on image-spectrum fusion information technology is superior to the single information model.Hyperspectral transmission imaging technology is effective and feasible to detect the fertile hatching eggs before incubation.

The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica

The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monocuhure and mixture of the two species were examined on the egg-hatching success ofArgopecten irradiarts Lamarck, and the population growth of Brachionus plicatilis MUller and Moina mongolica Daday. The results showed that monocuhure of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities （ED50） inhibiting the egg hatching success of A. irradhms for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm^3 , respectively. Monoculture of P. dongha/ense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis （ 1 × 10^4 ～ 3 ×10^4 cells/cm^3 ） and M. mongolica （2 × 10^4～5 ×10^4 cells/cm^3 ） ; P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis （4 × 10^4 ～ 10×10^4 cells/cm^3 ） and M. mongolica （ 10 ×10^4 cells/cm^3）. When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.

Effects of Lanthanum on Egg Hatching and Nauplius Metamorphosis of Penaeus Chinensis

Effects of lanthanum on egg hatching and nauplius metamorphosis of Penaeus chinensis(P. chinensis) were studied. The experimental results showed that the optimum concentration of lanthanum was 0 30～1 80 mg/L for monocell and dicell stage of embryo development, the egg hatching rates were raised by 33 5%～49 1%; and it was 0 90～1 80 mg/L for poly cell stage, the egg hatching rate was raised by 17 1%～23 5%. The optimum concentration was 0 90～1 50 mg/L for nauplius metamorphosis, the metamorphosis rate from nauplius(N 1) to protozoea(Z 1) was raised by 9 4%～11 7%. The promotion of lanthanum to egg embryo development was completed through absorption of lanthanum by egg in the water. The absorption capacity of one egg for lanthanum was 5 89 μg.

Incubation Effect on Eggs of Tibetan Chicken under Low Altitude Condition

[ Objective] In order to study incubation conditions of Tibetan chickens in low altitude areas. [ Method] Eggs of Tibetan chicken were transported to low altitude areas in highland areas for artificial hatching. [ Results] The results showed that the average hatching rate of fertilized eggs was 85.33% ; the average healthy chick rate was 91.77 % ; the average primary body mass was 31.2l g. Hatching rate of eggs in group 2 was the highest, which reached 90.52%, the aver- age egg mass was 43.25 g and the average egg shape index was 1.32. Hatching rate of eggs in group 2 was 13.11% and 2.47% higher than that in group 1 and group 3 respectively, which was 5.19% higher than the average value. Hatching rate and healthy chick rate of eggs in group 2 also showed the same trend. [ Conclusion] High hatching effect could be obtained under the better hatching condition in low altitude areas in highland areas.

Effects of Lanthanum-Amino Acid Complexes on Egg Hatching and Nauplius Metamorphosis of Penaeus chinensis

Studies have been carried out on the effect of lanthanum-amino acid complexes on embryo development and nauplius growth ofPenaeus chinensis. The experimental results indicate that: (1)The optimum concentrations of lanthanum-proline and Lanthanumphenylalanine for the development of eggs in monocell and dicell stages are 1.50～ 4.00mg/L and 0.50～3.00 mg/L, respectively, the egg hatching rates being raised by 21.0 ～ 46.0% and 23.0 ～42.8% ( P ＜ 0.05 ) respectively. (2)The optimum concentrations of lanthanum- proline complex and Lanthanum-phenylalanine complex for the growth ofnauplii are 1.50～4.00 mg/L and 0.50～3.00 mg/L, the metamorphosis rate from nauplius to protozoea being raised by 16.4 ～27.5% and 20.4～26.7% (P ＜ 0.05 ) respectively. (3)The positive effect of lanthanum-amino acid complexes on egg hatching and nauplius metamorphosis of Penaeus chinensis is better than that of lanthanum. With regard to the positive effect, lanthanum-proline complex is better than Lanthanum-phenylalanine complex.

Sea water environment copper requirement of egg hatching and naupliar metamorphosis of Peaneus chinensis

A new method was used to remove heavy metals in sea water. The requirement of copper in sea water ofegg hatching and naupliar metamorphosis of Penaeus chinensis was investored. A certain amount of copper ion andchelator nitrilotriacetic acid (NTA) were added in the de-heavy-metal-ionized sea water and then the cupric ion actvitywas calculated. The effects of copper ion on egg hatching and naupliar metamorphosis were observed. It was firstfound by experiments that trace ionic copper (10-10.80-10-8.80 mol/dm3) was essential to the growth and development of egg and nauplii of penaeid shrimp and chelated copper had no actions for these living processes,but in highconcentrations (>10 -7.80 mol/dm3) ionic copper was toxic. The nauplii were more sensitive to necessity and tokicityof ionic copper than eggs.

Raising of Horn Fly Haematobia irritans(L.)(Diptera:Muscidae)in Laboratory by Means of Egg and Larva Inoculation

Several studies have required Haematobia irritans (L.) raising in laboratory. The present study assessed two methods of inoculating immature forms of H. irritans to obtain adults. In 2007, 15 Nellore steers (Bos indicus) (L.) were used for the collection of feces free of anthelmintic treatment and flies to produce for eggs and larva. For method I, 30 eggs were incubated in square filter paper (5 × 5 cm) and deposited on bovine feces (500 g) where they were kept until hatching and spontaneous penetration of larvae (L1) into the fecal mass. After 24 h, eggs were analyzed under a stereoscope microscope (40×) for the number of larvae that instinctively penetrated the feces. In method II, larvae were obtained only by natural egg hatching. At birth, 30 larvae were collected and individually inoculated, directly onto the fecal plate by employing a moistened brush. The tests were carried out at controlled temperature (28°C ± 2°C) and saturated humidity (80%) until the emergence of flies with both methods. The number of emerged flies was considered in the result. Using method I, 276 (76.7%) flies emerged from 360 inoculated eggs, while using method II, 283 (78.6%) flies emerged from 360 inoculated larvae. There was no significant difference (P = 0.7821) between methods for the number of flies;however, the proportion between males and females by means of larva inoculation was different from 1:1 (P = 0.0146). Results indicated that both methods led to a satisfactory production of flies and egg inoculation provided an easier establishment.

eIF3 subunit M regulates blood meal digestion in Rhodnius prolixus affecting ecdysis, reproduction, and survival

In triatomines,blood-feeding triggers many physiological processes including post embryonic development and reproduction.Different feeding habits,such as hematophagy,can shape gene functions to meet the challenges of each type of diet.The gut of blood-sucking insects faces particular challenges after feeding due to the quantity and the quality of the food ingested.A comparison of transcriptomic and proteomic data indicates that post transcriptional regulation of gene expression is crucial in the triatomine gut.It was proposed that eukaryotic translation initiation factor 3 subunit m(eIF3m)and eIF3e define 2 different eIF3 complexes with a distinct affinity for the different mRNAs,thus selecting the set of mRNAs to be translated and constituting a post transcriptional mode of regulation of gene expression.Because the eIF3m is mainly expressed in the gut,we evaluated its relevance in Rhodnius prolixus physiology through RNA interference-mediated gene silencing.The knockdown of eIF3m reduced the digestion rate,affecting the processes triggered by a blood meal.Its silencing inhibited molting and caused premature death in nymphs while impaired ovary development,oviposition and increased resistance to starvation in adult females.The survival of males after feeding(resistance to starvation)was not affected by eIF3m knockdown.The information regarding the eIF3m function in insects is scarce and the phenotypes observed in R.prolixus upon eIF3m silencing are different and more severe than those previously described in Drosophila melanogaster,indicating a pleiotropic role of this gene in triatomines.