The tribe Bythinini Raffray is species-rich pselaphine group including over 600 species distributed worldwide. Despite its diversity, only one genus, Bryaxis Kugelann, has been reported in Korea. In this study, we newly describe Bryaxis sp. n. mainly based on the male antennal modification. We also report a new species of the genus Tychobythinus Ganglbauer from Korea. Members of these two bythinine genera are commonly characterized by the traits of maxillary palpi: elongated second palpomere, shortened penultimate, and enlarged last one. In addition, we conducted phylogenetic analyses to demonstrate the relevance between antennal modification and evolutionary relationship of Bryaxis. To perform the phylogenetic construction, we assembled three mitochondrial genes (cox1, cox2, and 16S) and three nuclear genes (18S, 28S, and wingless) into a dataset. Eleven species of Bryaxis and two Tychobythinus species are included, the latter genus of which are used to root the consensus trees.
Goniaceritae is the most speciose supertribe of the subfamily Pselaphinae with more than 3,000 species worldwide. Brachyglutini is the only tribe within New Zealand Goniaceritae, comprised of 8 genera. Physobryaxis Hetschko is monotypic genus of the subtribe Brachyglutina. Although the adults of P. inflatus is close to the members of genus Gastrobothrus Broun, 1882, it is characterized by median antebasal fovea and antebasal sulcus on pronotum. In this study, we report six species of Physobryaxis examining 21 specimens. Illustrations of the habitus, diagnostic characters including male genitalia, and key to the species are also provided. Additionally, we present a distributional map divided into areas based on Crosby’s code.
The genus Nipponobythus was first described by Jeannel in 1958 from Japan based on Nipponobythus syrbatoides Jeannel 1958. Löbl described the genus Machulkaia (type species: Machulkaia mirabilis Löbl 1964), but it was synonymized under Nipponobythus later. Nipponobythus holds 14 species from Korea, Japan and China. Three species (N. chilisanus, N. dolharubang and N. omissus) are currently recorded in Korea. Members of this genus can be distinguished from other pselaphine genera in having concave frons with golden pubescence in males. Here we describe a new species of Nipponobythus from Mt. Gahak, Jeollanam-do, South Korea. This new species is externally similar to N. chilisanus Nomura & Lee 1996, but has differences in male genitalia.
Nitrite and nitrates are usually used in the production of meat products as food additives even though they pose a secondary risk. In this study, the residues of nitrite and nitrate ions in 366 processed meat products distributed in Seoul were analyzed using ion chromatographs and UV spectrophotometers. In all tested products, the residues of nitrite were below 70 mg/kg, which met the processing standard and component specification for livestock products.
Evaluation of nitrite ions, revealed a mean concentration of 7.1 - 11.9 mg/kg in hams, sausages, and bacons, while higher ratios of nitrite were found in other types of products. Among the studied processed meat products, at least 60% of hams and sausages had indications of nitrite, as did 90% of bacons and dry meats. No spiced meat and less than 10% of crushed meat had indications of nitrite. However, all dried meats showed below 1 mg/kg, regardless of whether they had indications of nitrite. Up to 9.7 mg/kg of nitrite was detected in the products with no indication of nitrite, and 14.6% of all products had at least 1 mg/kg of nitrite. This can be attributed to the reduction of residual nitrate ions in the products into nitrite ions.
A review of the concentrations of nitrate ions in processed meat products by type suggests that the mean concentration was 22.3 (maximum 110.2) mg/kg in hams, 31.8 (maximum 89.5) mg/kg in sausages, 16.4 (maximum 28.2) mg/kg in bacons, 16.8 (maximum 61.1) mg/kg in spiced meats, 20.2 (maximum 99.4) mg/kg in crushed meats, and 121.0 (maximum 216.5) mg/kg in dried meats. Therefore, dried meats showed much higher nitrate ion concentrations than other types of meat products; however, the residue of nitrite ions in actual dried meats was found to be lower than 1 mg/kg, suggesting that the concentrations of nitrate ions do not affect those of nitrite ions. However, a certain concentration of nitrate ions was observed even when nitrate ions were not used in the products, as nitrite ions were transformed into nitrate ions and nitrite ions were detected even the products with no indication of nitrite ions. Therefore, continuous monitoring and preparation of relevant standards of the use of nitrate in processed meat products are necessary.
Bakanae disease is one of the most serious and oldest problems of rice production, which was first described in 1828 in Japan (Ito and Kimura 1931). This disease may infect rice plants from the pre-emergence stage to the mature stage, with severe infection of rice seeds resulting poor germination or withering (Iqbal et al. 2011). Under favorable environmental conditions, infected plants have the capacity to produce numerous conidia that subsequently infect proximate healthy plants, resulting in major yield loss (Ou 1985). One hundred sixty nine NILs, YR28297 (BC6F4) generated by five backcrosses of Shingwang with the genetic background of susceptible japonica variety, Ilpum were used for QTL analysis. Rice bakanae disease pathogen, CF283, was mainly used in this study and inoculation and evaluation of bakanae disease was performed with the method of the large-scale screening method developed by Kim et al. (2014). A major QTL for resistance against bakanae disease on chromosome 1 was identified using SSR marker, RM9, which explaining 65 % of the total phenotype variation. The major QTL designated as qBK1 and mapped to a 4.4 Mbp region between RM24 (19.30 Mb) and RM11295 (23.72 Mb). The results of this study are expected to provide useful information toward developing resistant rice lines to this detrimental fungal disease.
Bakanae disease incidence threat is an increasing trend in the top rice growing countries. Despite it is essential to identify the resistant genes and underlying mechanisms of bakanae disease to develop resistant varieties, there are very limited genetic studies on bakanae disease in rice. The indica rice variety Shingwang was selected as resistant donor to bakanae disease. One hundred sixty nine NILs, YR28297 (BC6F4) generated by five backcrosses of Shingwang with the genetic background of susceptible japonica variety, Ilpum were used for QTL analysis. Rice bakanae disease pathogen, CF283, was mainly used in this study and inoculation and evaluation of bakanae disease was performed with the method of the large-scale screening method developed by Kim et al. (2014). The proportion of healthy plants of Shingwang and Ilpum after inoculation was confirmed using bakanae disease pathogen, CF283. While inoculated Ilpum showed thin and yellowish-green phenotype which is typical symptom of Bakanae disease, Shingwang showed similar healthy phenotype with control plants. A major QTL for resistance against bakanae disease on chromosome 1 was identified using SSR marker, RM9, which explaining 65 % of the total phenotype variation. The major QTL designated as qBK1 and mapped to a 4.4 Mbp region between RM24 (19.30 Mb) and RM11295 (23.72 Mb). The information of qBK1 could be useful for improving rice bakanae disease resistance in marker-assisted breeding.