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Distribution of Wolbachia infection in butterflies (Lepidoptera): First systematic report from Thailand
(2023-01-01)
Boonsit, Panukorn
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Wiwatanaratanabutr, Itsanun
;
Ross, Perran A
;
Grandjean, Frederic
;
Austin, Chris
Wolbachia is a genus of Rickettsia-like bacteria that infects a broad range of insect species throughout the world. It often influences host reproduction to facilitate its transmission to their offspring and spread through populations. The occurrence and ecology of Wolbachia has not been surveyed in detail in Thai butterflies. In this study, we conduct the first systematic survey of Wolbachia infection by sampling 623 specimens from 46 butterfly species from 5 families obtained from tropical forests in 3 geographic regions of Thailand. Wolbachia infections were detected using three PCR primer sets: 16S rRNA, ftsZ and wsp. The results showed evidence for widespread Wolbachia infection in Thai butterflies. The Wolbachia presence was confirmed in 291 individuals from 17 butterfly species of 2 families, comprising 86 individuals from the Central Region (32 males and 54 females), 72 individuals from the Northeast Region (25 males and 47 females), and 133 individuals from the West Region (46 males and 87 females). This report will be useful for understanding the distribution of Wolbachia in butterflies from Thailand.
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Infection density, diversity, and distribution of Wolbachia bacteria in moths (Order Lepidoptera): First systematic report from Thailand
(2021-08-01)
Boonsit, Panukorn
;
Wiwatanaratanabutr, Itsanun
Members of the genus Wolbachia are a group of Rickettsia-like, intracellular, maternally inherited bacterial endosymbionts that infect a diverse range of insects and cause reproductive changes in their hosts. Although Wolbachia's role in many insects has been extensively studied, only a little of their effects on host's reproduction and their infection frequencies were reported in Lepidopteran which is one of the most diverse insects. Here, we present the first systematic survey of the Wolbachia infection status in different species of moths from three different geographic regions of Thailand, which was carried out during January to December in 2019 with the screening of 1,235 specimens in total of 58 moth species from 13 families. Specimens were collected from Khao Yai National Park (the Central and the Northeast regions), and Kaeng Krachan National Park (the West region). Infections of Wolbachia were screened by using polymerase chain reaction with 16S rRNA, ftsZ and wsp gene primers which the results indicated high rates of Wolbachia infection in moth populations from Thailand. Wolbachia was found in all different geographically populations in total of 625 individuals in total of 28 moth species from 9 families, including 144 individuals (46 males and 98 females) from the Central, 156 individuals (49 males and 107 females) from the Northeast, and 325 individuals (114 males and 211 females) from the West. The highest infection rate was 90.47% in the West populations and the average infection rate was 61.90%. The detection of Wolbachia in different moth populations from all regions was identical when all primers were used to screen for Wolbachia. The relative densities of Wolbachia within each individual were determined using quantitative real-time PCR and the result showed that there was a low Wolbachia infection density in these moth populations. These findings indicated that Wolbachia are distributed throughout the moth populations from Thailand.
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Outdoor open pond batch production of green microalga Botryococcus braunii for high hydrocarbon production: enhanced production with salinity
(2020-12-01)
Ruangsomboon, Suneerat
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Dimak, Jantra
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Jongput, Buppha
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Wiwatanaratanabutr, Itsanun
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Kanyawongha, Pornthiwa
The aim of this work was to enhance the biodiesel quality and hydrocarbon content of green microalga B. braunii strain KMITL 2 cultivated outdoor under several salinity conditions in a batch production. The enhancement would be such that the microalgal biodiesel qualities met or exceeded the current standard so that it would be a good raw material for biodiesel production. The microalga production was in 300 L open oval ponds, among various salinity levels tested (0–20 ppt), 5 ppt was the best for hydrocarbon production, yielding 54.2 ± 0.9% hydrocarbon content and 5.1 ± 0.4 g L−1 biomass. As the microalga production was scaled up by cultivation in 3,675 L open raceway pond under the 5 ppt condition, the microalga yielded a bit higher hydrocarbon content (58.8 ± 2.9%) but much lower biomass (2.5 ± 0.5 g L−1). The production in both oval and raceway ponds yielded a nearly identical biodiesel property (61.06–67.42 cetane number) which exceeded the value specified in international standards. Therefore, it was concluded that B. braunii strain KMITL 2 can be batch cultivated in an open pond at optimum salinity to yield sufficient hydrocarbon and biomass for biodiesel production.
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NisI maturation and its influence on nisin resistance in Lactococcus lactis
(2020-10-01)
Liu, Jiaheng
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Xiong, Hui
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Du, Yuhui
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Wiwatanaratanabutr, Itsanun
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Wu, Xiaofang
NisI confers immunity against nisin, with high substrate specificity to prevent a suicidal effect in nisin-producing Lactococcus lactis strains. However, the NisI maturation process as well as its influence on nisin resistance has not been characterized. Here, we report the roles of lipoprotein signal peptidase II (Lsp) and prolipoprotein diacylglyceryl transferase (Lgt) in NisI maturation and nisin resistance of L. lactis F44. We found that the resistance of nisin of an Lsp-deficient mutant remarkably decreased, while no significant differences in growth were observed. We demonstrated that Lsp could cleave signal peptide of NisI precursor in vitro. Moreover, diacylglyceryl modification of NisI catalyzed by Lgt played a decisive role in attachment of NisI on the cell envelope, while it exhibited no effects on cleavage of the signal peptides of NisI precursor. The dissociation constant (KD) for the interaction between nisin and NisI exhibited a 2.8-fold increase compared with that between nisin and pre-NisI with signal peptide by surface plasmon resonance (SPR) analysis, providing evidence that Lsp-catalyzed signal peptide cleavage was critical for the immune activity of NisI. Our study revealed the process of NisI maturation in L. lactis and presented a potential strategy to enhance industrial nisin production.
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Simultaneous hydrolysis and fermentation of defatted rice bran and defatted soybean meal for nisin production with engineered Lactococcus lactis
(2020-08-01)
Liu, Jiaheng
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He, Xiangyu
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Du, Yuhui
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Wiwatanaratanabutr, Itsanun
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Zhao, Guangrong
This work aimed to study the potential of defatted rice bran (DRB) and defatted soybean meal (DSM) as carbon and nitrogen sources for Lactococcus lactis growth and nisin production. First, a maximum nisin yield of 3630 IU/mL was achieved using 40% DRB hydrolysates and 30% DSM hydrolysates, which was 1.13 times greater than that found in commercial media. Second, to simplify the operation and shorten the length of the entire process, the processes of combined hydrolysis of DRB-DSM followed by fermentation, and simultaneous hydrolysis and fermentation of DRB-DSM were developed. Neutral proteinase enhanced the saccharification of DRB by cellulase and α-amylase. Furthermore, the strategy of NADH oxidase expression and hemin addition was innovatively proposed to overcome the oxygen stress in a simultaneous hydrolysis and fermentation process, which could alleviate the lag period following inoculation of L. lactis and result in a 77.3% increase in nisin titer.
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Host serum iron modulates dengue virus acquisition by mosquitoes
(2019-12-01)
Zhu, Yibin
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Tong, Liangqin
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Nie, Kaixiao
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Wiwatanaratanabutr, Itsanun
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Sun, Peng
A blood meal is the primary route through which mosquitoes acquire an arbovirus infection. Blood components or their metabolites may regulate the susceptibility of mosquitoes to arboviruses. Here we report that serum iron in human blood influences dengue virus acquisition by mosquitoes. Dengue virus acquisition by Aedes aegypti was inversely correlated with the iron concentration in serum from human donors. In a mouse–mosquito acquisition model, iron supplementation reduced dengue virus prevalence and viral load, whereas neutralization of serum iron facilitated dengue virus infection in A. aegypti mosquitoes. Of note, mosquitoes feeding on iron-deficient (sideropenic) mice exhibited a higher prevalence of dengue virus. Reversal of the sideropenic status of hosts largely reduced dengue virus acquisition and infection by mosquitoes. Serum iron, rather than haem-bound iron, was utilized by the mosquito iron metabolism pathway to boost the activity of reactive oxygen species in the gut epithelium, subsequently inhibiting infection by dengue virus. On the basis of these results, a status of iron deficiency in the human population might contribute to the vectorial permissiveness to dengue virus, thereby facilitating its spread by mosquitoes.
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Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress
(2017-01-01)
Ross, Perran A.
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Wiwatanaratanabutr, Itsanun
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Axford, Jason K.
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White, Vanessa L.
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Endersby-Harshman, Nancy M.
Aedes aegypti mosquitoes infected with Wolbachia bacteria are currently being released for arbovirus suppression around the world. Their potential to invade populations and persist will depend on interactions with environmental conditions, particularly as larvae are often exposed to fluctuating and extreme temperatures in the field. We reared Ae. aegypti larvae infected with different types of Wolbachia (wMel, wAlbB and wMelPop-CLA) under diurnal cyclical temperatures. Rearing wMel and wMelPop-CLA-infected larvae at 26–37°C reduced the expression of cytoplasmic incompatibility, a reproductive manipulation induced by Wolbachia. We also observed a sharp reduction in the density of Wolbachia in adults. Furthermore, the wMel and wMelPop-CLA infections were not transmitted to the next generation when mosquitoes were exposed to 26–37°C across all life stages. In contrast, the wAlbB infection was maintained at a high density, exhibited complete cytoplasmic incompatibility, and was transmitted from mother to offspring with a high fidelity under this temperature cycle. These findings have implications for the potential success of Wolbachia interventions across different environments and highlight the importance of temperature control in rearing.
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Impacts of temperature and crowding on sex ratio, fecundity and Wolbachia infection intensity in the copepod, Mesocyclops thermocyclopoides
(2016-11-01)
Wiwatanaratanabutr, Itsanun
;
Grandjean, Frederic
Wolbachia are a group of intracellular bacteria that cause reproductive alterations in arthropods. Here, we describe the effects of two environmental factors (crowding and temperature) on phenotypic expression of feminization, the host's fecundity and Wolbachia infection intensity among life cycle stages in the naturally Wolbachia-infected copepod, Mesocyclops thermocyclopoides. The copepod was first found to be co-infected with Wolbachia A- and B-supergroups Wolbachia strains based on wsp primers. The relative Wolbachia infection intensity within individuals was determined using quantitative real-time PCR and was significantly higher in the B-supergroup than in the A-supergroup. Experimental results of temperature effect on bacterial density in each developmental stage revealed a significant decrease in Wolbachia infection intensity following exposure to high temperature (37 °C) in both sexes and implied that Wolbachia might survive in room temperature (25 °C) better than in high temperature. Experimental results of crowding effects on Wolbachia infection intensity suggested a negative correlation between copepod nauplii and Wolbachia infection intensity. No effect of rearing temperature on the sex ratio was reported although the fecundity was significantly decreased by high temperature. The results showed that Wolbachia infection intensity to be correlated with crowding conditions and was decreased following exposure of elevated temperature.
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Wolbachia infections in mosquitoes and their predators inhabiting rice field communities in Thailand and China
(2016-07-01)
Wiwatanaratanabutr, Itsanun
;
Zhang, Chongxing
Wolbachia are inherited, endocytoplasmic bacteria that infect a wide range of arthropods. Here is the first systematic report on the study of Wolbachia infection in mosquitoes and their predators from both Thailand and China. In Thailand, 632 mosquito specimens (20 spp.) and 424 insect predators (23 spp.) were collected from the rice agroecosystem, mostly from the Central region, followed by the Northeast, the North and the South and were inhabiting rice fields, wetlands and ditches. In China, 928 mosquitoes (15 spp.) and 149 insect predators (16 spp.) were collected from rice fields along the Weishan Lake in Shandong province. Specimens were classified in the orders Diptera, Coleoptera, Odonata and Hemiptera. Using wsp, ftsZ, 16S rRNA and groE gene amplifications, Wolbachia were detected in 12 mosquito spp. and 6 predator spp. from Thailand and 11 mosquito spp. and 5 predator spp. from China. The relative Wolbachia densities of these species were determined using quantitative real-time PCR. The mosquito, Aedes albopictus, and the predator, Agriocnemis femina, had the highest bacterial densities. These results imply that Wolbachia of supergroup B are distributed throughout these insects, probably via horizontal transmission in rice agroecosystems.
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Evaluation of isotope 32P method to mark Culex pipiens (Diptera: Culicidae) in a laboratory
(2016-01-01)
Zhang, Chongxing
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Shi, Guihong
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Zhao, Yuqiang
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Yan, Dongmei
;
Li, Huaiju
Background: The aim of the current study was to develop a marking technique as an internal marker to mark post blood meal mosquitoes by using stable phosphate isotope 32P and determine the optimal concentration of it. Methods: An isotonic physiological saline solution, containing different concentration of radioactive isotope 32P-labeled disodium phosphate (Na<inf>2</inf>H32PO4) was injected into rabbits via the jugular vein in the laboratory. Emerged Cx. pipiens were marked after feeding on rabbit. At the same time, the labeled conditions of emerged Cx. pipiens were also measured by placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside. Results: According to the label condition of Cx. pipiens after taking blood and the effect of different dosage Na<inf>2</inf>H32PO4 on rabbit health, the optimal concentration of radioactive isotope was determined, that is, 0.1211 mCi/kg. By placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside, the emerged mosquitoes were also labeled. Therefore, feeding mosquitoes on the animal injected with radioactive Na<inf>2</inf>H32PO4 was more practical for detecting and tracing mosquitoes. Conclusion: The method was less time-consuming, more sensitive and safer. This marking method will facilitate post-bloodmeal studies of mosquitoes and other blood-sucking insects.

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