The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) will provide all-sky spectral survey data covering optical to mid-infrared wavelengths with a spatial resolution of 6.′′2, which can be widely used to study galaxy formation and evolution. We investigate the galaxy-galaxy blending in SPHEREx datasets using the mock galaxy catalogs generated from cosmological simulations and observational data. Only ∼0.7% of the galaxies will be blended with other galaxies in all-sky survey data with a limiting magnitude of 19 AB mag. However, the fraction of blended galaxies dramatically increases to ∼7–9% in the deep survey area around the ecliptic poles, where the depth reaches ∼22 AB mag. We examine the impact of the blending in the number count and luminosity function analyses using the SPHEREx data. We find that the number count can be overestimated by up to 10–20% in the deep regions due to the flux boosting, suggesting that the impact of galaxy-galaxy blending on the number count is moderate. However, galaxy-galaxy blending can marginally change the luminosity function by up to 50% over a wide range of redshifts. As we only employ the magnitude limit at Ks-band for the source detection, the blending fractions determined in this study should be regarded as lower limits.

Veronica L., the largest genus in the family Plantaginaceae, is widespread in various habitats. Due to their long-blooming flowers, Veronica species have high horticultural value as indoor potted, garden, and landscape plants. Furthermore, Veronica plants are extremely important owing to their notable diversity in habitat usage, ploidy level, and evolution. Several native taxa, which are of key interest in breeding programs and phylogenetic studies, have been identified in Korea. The genome sizes and chromosomal characteristics are basic cytogenetic features of all taxa, and their knowledge is a prerequisite when commencing genome sequencing projects. It can provide essential information for cytogenetic, taxonomic, phylogenetic, and evolutionary studies. Thus, cytogenetic analysis and genome size estimation of seven Veronica taxa native to Korea were conducted in this study. Fluorescence in situ hybridization (FISH) karyotype analysis and chromosome counting was conducted using metaphase chromosomes probed with 5S and 45S rDNA. Nuclear DNA content and genome size were determined using flow cytometry. FISH karyotype analysis revealed a common number of 5S loci and varying 45S signals that create distinctive rDNA distribution patterns in each taxon. The results indicated that the seven investigated Veronica taxa have calculated genome sizes (1C values) ranging from 517.1 to 862.0 Mbp. This study is the first to report the chromosome number and karyomorphology of seven Veronica taxa native to Korea, as well as the use of rDNA markers for identifying individual chromosomes. These findings contribute to the crucial understanding the genomic characteristics of species within the genus Veronica, serve as a basis for studying Veronica phylogeny and evolution, and provide valuable information for future breeding programs.

Samples were collected from benthic and subaerophytic habitats of fresh and brackish water in Korea from April 2017 to April 2018. Accordingly, three genera and seven species were newly recorded in Korea. Three unrecorded genera were Cephalothrix, Cyanophanon and Toxifilum, and seven species were Anagnostidinema pseudacutissimum, Calothrix elenkinii, Cephalothrix komarekiana, Cyanophanon mirabile, Cyanosarcina chroococcoides, Leptolyngbya ectocarpi and Toxifilum mysidocida. Anagnostidinema pseudacutissimum and Cephalothrix komarekiana had been previously reported to inhabit freshwater, but these were found to be present in brackish water during the period of the present study. Also, Cyanosarcina chroococcoides previously reported to inhabit moorland waters and swamps, were found to be present in subaerophytic habitat.

Phytoplanktons were collected from various environments including small marshes, small ponds, reservoirs and brackish water from March 2017 to November 2017. In this study, five species of family Scenedesmaceae were newly recorded in Korea. The genus Desmodesmus was newly reported in Korea. The newly recorded species are Scenedesmus nanus, S. praetervisus, Desmodesmus costato-granulatus, D. lunatus and D. spinulatus. S. nanus and S. praetervisus are known to occur in freshwater, but they were found in the brackish water in this study.

Insect growth regulators (IGRs) are insecticides that disrupt the normal development of target insects. Among the IGR insecticides, juvenile hormone (JH)-related IGRs are of particular interest because they stimulate or interfere with the formation of JH receptor complex. In the precious studies, novel JH-related IGRs with JH agonist (JHA) and antagonist (JHAN) activity were identified by using yeast two-hybrid system transformed with the Aedes aegypti JH receptor complex. In this study, the transcriptomic responses of Aedes albopictus were investigated upon JHA and JHAN, respectively. These results will provide important information about understanding of impact of JH-related IGRs in transcription level.

The small brown planthopper (SBPH), Laodelphax striatellus, is one of the most serious pest insects of rice plants.Buprofezin has been used to control SBPH for more than a decade, however, the occurrence of buprofezin resistant SBPHwas reported recently. To develop an alternative pest control an alternative pest control strategy, RNA-seq of buprofezin-treatedSBPH was performed to screen the insecticidal target genes for RNA interference (RNAi). Six genes were selected fordsRNA synthesis, and applied to SBPH to assess the insecticidal efficacy. Two and three of those dsRNAs showed moderatedand substantial insecticidal activity up to 60% of mortality in one week, respectively. These results demonstrated the potentialof gene screening strategy for the development of RNAi-based pest management program.

Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. Theyproduce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenicfungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanismsof host insect. In this study, Acetone extracts of 189 entomopathogenic fungi cultured on unpolished rice medium werescreened for their juvenile hormone antagonist (JHAN) activities using the yeast-two hybrid system. Among them, 14extracts showed high level of JHAN activities and their insecticidal activities against Aedes albopictus were investigated.

Widespread use of chemical insecticides has resulted in development of insect resistance and natural products withbiological activities could become an attractive alternative to control insect pests. In order to find more effective insecticidesfor controlling mosquito, various mosquitocidal compounds are studied. Recently, juvenile hormone antagonists (JHANs)are known to be to safe and effective insecticides for control mosquito. In order to identify novel insecticidal compoundswith JHAN activity, several chalcones were surveyed on their JHAN activities and larvicidal activities against Aedes albopictuslarvae. Among them, 2’-hydroxychalcone and cardamonin showed high level of JHAN and mosquito larvicidal activities.These results suggested that chalcones with JHAN activity could be useful for control of mosquito larvae.

Actinobacteria have been known to produce variety of bioactive metabolites that include antibiotics and plant growthfactor. Also, Insecticidal compounds such as avermectin and tetranectin have been reported from actinobacteria. In thisstudy, to identify novel insect growth regulator (IGR)-based insecticidal compounds, 1,283 actinobacteria isolates weretested for their juvenile hormone antagonist (JHAN) activity using the yeast-two hybrid β-galactosidase assay. Amongthem, 25 isolates showed high level of JHAN activity and insecticidal activity against 3rd larvae of diamondback moth,Plutella xylostella. These results suggested that actinobacteria could be unparalleled source of novel IGR-based compounds.

Streptomyces species have been studied to find potent pest control agents as an alternatives to chemical insecticides.Previously, one of the ethyl acetate extract of Streptomyces isolates cultured on unpolished rice medium showed highlevel of juvenile hormone antagonist and larvicidal activities against pest insects including Aedes albopictus, Plutella xylostellaand Laodelphax striatellus. It has been known that the biosynthesis of secondary metabolites of Streptomyces could beinfluenced by a variety environments such as nutritional composition and growth conditions. In this study, to optimizeculture conditions for stable production of insecticidal compounds from this isolate, binding assay and bioassay-guidedmonitoring were conducted using various culture conditions.

Recently, it has been reported that plants produce variety of phytochemicals against insect pests as a part of their defencemechanism. In this study, to identify novel compounds that disrupt juvenile hormone (JH) receptor complex, plant essentialoil compounds were tested using in vitro yeast two-hybrid system transformed with the Aedes aegypti JH receptor complex.Among the plant essential oil compounds, farnesol interfered with pyriproxyfen-mediated binding of A. aegypti Met-FISC.In contrast, farnesyl acetate induced the binding of A. aegypti Met-FISC. Also, both compounds caused retardation ofovarian development and change of transcription level in female A. albopictus. These results could provide insights onthe plant-insect coevolution and may be useful for the development of insect specific and safe pesticides.

RNA interference (RNAi) has been considered as an alternative strategy to control agricultural pests whereby double-strandedRNA triggers a potent and specific inhibition of its homologous mRNA. Since small double-stranded RNAs are requiredfor various RNAi applications, there is a need for cost-effective methods for producing large quantities of high-qualitydsRNA. Bacillus thuringiensis produces much insecticidal proteins with expression of their encoding genes being drivenby sporulation-dependent promoters. To develop dsRNA mass-production platform utilizing Bt, the pHT1K-EGFP plasmidvector which has cyt1Aa sporulation-dependent promoter was constructed. The transcriptional level of target gene (EGFP)is higher 113 times than Bt reference gene (ssPE). It was applied to protect honeybee from Sacbrood virus, so targetgene was replaced to SBV-vp1. By ingestion of Bt-derived dsRNA to honeybee shows positive effect on SBV suppression.

Secondary metabolites isolated from Actinomycete have been studied to find potent pest control agents as their insecticidal and growth inhibitory activities. In order to investigate novel insecticidal compounds, second metabolites from 363 Actinomycete isolates were evaluated for their insect growth regulatory activities. Among them, ethyl acetate extracts from ten Streptomyces spp. showed high level of Juvenile hormone antagonist activity. In addition, their insecticidal activities were tested against larvae of Aedes albopictus, Plutella xylostella and Laodelphax striatellus. These results suggested that secondary metabolites from Streptomyces spp. could be used for development of novel IGR-based insecticides.