Genome-wide identification of Coptotermes formosanus immune genes and their potential roles in termite control.

In recent years, the use of microbes to control termites has attracted increasing attention. It was found that pathogenic bacteria, nematodes, and fungi effectively control termites under laboratory conditions. However, their effects have not been replicated in the field, and one reason for this is the complex immune defense mechanisms of termites, which are mainly regulated by immune genes. Therefore, altering the expression of immune genes may have a positive influence on the biocontrol efficacy of termites. Coptotermes formosanus Shiraki is one of the most economically important termite pests worldwide. Currently, the large-scale identification of immune genes in C. formosanus is primarily based on cDNA library or transcriptome data rather than at the genomic level. In this study, we identified the immune genes of C. formosanus according to genome-wide analysis. In addition, our transcriptome analysis showed that immune genes were significantly downregulated when C. formosanus was exposed to the fungus Metarhizium anisopliae or nematodes. Finally, we found that injecting dsRNA to inhibit three immune genes (CfPGRP-SC1, CfSCRB3, and CfHemocytin), which recognize infectious microbes, significantly increased the lethal effect of M. anisopliae on termites. These immune genes show great potential for C. formosanus management based on RNAi. These results also increase the number of known immune genes in C. formosanus which will provide a more comprehensive insight into the molecular basis of immunity in termites.

Combined use of lipopolysaccharide-binding protein dsRNA and Gram-negative bacteria for pest management of Coptotermes formosanus.

BACKGROUND: RNA interference (RNAi) technology is an environmentally friendly strategy for controlling insect pests. Lipopolysaccharide-binding protein (LBP) recognizes lipopolysaccharides, which are a major outer membrane constituent of Gram-negative bacteria. We propose that the LBP gene is a potential target for termite management; however, to date, no studies have examined this gene in termites. RESULTS: In this study, we cloned the LBP gene of Coptotermes formosanus (Cf) and found that the mortality rate of termite workers significantly increased, and the repellence of these workers to Gram-negative bacteria was suppressed after knockdown of CfLBP using double-stranded RNA (dsRNA) injection and feeding. Moreover, the mortality rate of termite workers fed with CfLBP dsRNA and three Gram-negative bacteria (provided separately) was over 50%, which was much higher than that of termites treated with either CfLBP dsRNA or Gram-negative bacteria. Finally, we found that CfLBP impacts the IMD pathway to regulate the immune response of C. formosanus to Gram-negative bacteria. CONCLUSION: CfLBP plays a important role in the immune defense of termites against Gram-negative bacteria. It can be used as an immunosuppressant for RNAi-based termite management and is an ideal target for termite control based on the combined use of RNAi and pathogenic bacteria. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Colon Interposition for Corrosive Esophageal Stricture: Single Institution Experience with 119 Cases.

The colon is an alternative graft organ for esophageal reconstruction. The present study reviewed our experience with the colon interposition for esophageal replacement following corrosive ingestion, to evaluate the outcomes of colon interposition based on our surgical experience. The clinical data of 119 patients who underwent colon interposition for esophageal replacement from January 2005 to March 2017 were retrospectively analyzed. The routes of the colon interposition were retrosternal in 119 (100%). The median operative time was 390 min (range: 290-610 min) and the median blood loss was 615 mL (range: 270-2500 mL). Of these 119 patients, the cervical anastomosis was performed at the hypopharynx (n=20, 16.8%), the larynx (n=3, 2.5%), and the cervical esophagus (n=96, 80.7%). Five patients experienced cervical anastomotic leakage (4 cases for esophagus-colon, and one for hypopharynx-colon). One patient experienced wound infection of the abdominal wall. Three patients had injury of recurrent laryngeal nerve and hoarseness. Three patients had stress ulcer with bleeding and treated with octreotide. Two patients suffered from incomplete intestinal obstruction. The postoperative follow-up was made for 12 months in all patients and all of them were alive. In conclusion, The colon is well-suited for esophageal reconstruction. The selection of the colon graft should be flexible and be based on the inspection of blood supply and the length needed. We must therefore make every effort to reduce the number of postoperative complications, and improve the quality of life for patients.

A mitochondria-targeted fluorescence probe for ratiometric detection of endogenous hypochlorite in the living cells.

A mitochondria-targeted fluorescence probe (CPBT) for ratiometric detection of endogenous hypochlorite in the living cells was developed. CPBT could detect hypochlorite with high selectivity and sensitivity in a ratiometric manner based on FRET mechanism. In absence of hypochlorite, when CPBT was excited with absorption maximum wavelength of the donor moiety, it showed the emission of acceptor moiety because of FRET process. However, in the presence of hypochlorite, the reaction of CC double bond with hypochlorite interrupted the conjugation system resulting in the inhibition of FRET process and the emission of the donor moiety. The two well-resolved emission bands can ensure accurate detection of hypochlorite. A good linear relationship between the fluorescence intensity ratios of the two emissions and the ClO- concentrations in the range from 41.8 nM (detection limit) to 12.5 µM was established. Importantly, CPBT could localize mainly in the mitochondria of RAW264.7 cells. CPBT was successfully used to fluorescence ratiometric imaging of endogenous hypochlorite in RAW264.7 cells.

Response of Termite (Blattodea: Termitoidae) Assemblages to Lower Subtropical Forest Succession: A Case Study in Dinghushan Biosphere Reserve, China.

Termite (Blattodea: Termitoidae) assemblages have important ecological functions and vary in structure between habitats, but have not been studied in lower subtropical forests. To examine whether differences in the richness and relative abundance of termite species and functional groups occur in lower subtropical regions, termite assemblages were sampled in Dinghushan Biosphere Reserve, China, among pine forest, pine and broad-leaved mixed forest (mixed forest), and monsoon evergreen broad-leaved forest (monsoon forest). The dominant functional group was wood-feeding termites (family Termitidae), and the mixed forest hosted the greatest richness and relative abundance. Soil-feeding termites were absent from the lower subtropical system, while humus-feeding termites were sporadically distributed in mixed forest and monsoon forest. The species richness and functional group abundance of termites in our site may be linked to the forest succession. Altitude, soil temperature, air temperature, surface air relative humidity, and litter depth were significant influences on species and functional group diversity.

Purification and characterization of a thermostable xylanase from Paenibacillus sp. NF1 and its application in xylooligosaccharides production.

High levels of extracellular xylanase activity (211.79 IU/mg) produced by Paenibacillus sp. NF1 were detected when it was submerged-cultured. After three consecutive purification steps using Octyl-Sepharose, Sephadex G75, and Q-Sepharose columns, a thermostable xylanase (XynNF) was purified to homogeneity and showed a molecular mass of 37 kDa according to SDS-PAGE. The specific activity of the purified XynNF was up to 3,081.05 IU/mg with a 14.55-fold purification. The activity of XynNF was stimulated by Ca(2+), Ba(2+), DTT, and ß-mercaptoethanol, but was inhibited by Fe(3+), Zn(2+), Fe(2+), Cu(2+), SDS, and EDTA. The purified XynNF displayed a greater affinity for oat spelt xylan with the maximal enzymatic activity at 60°C and pH 6.0. XynNF, which was shown to be cellulose-free, with high stability at high temperature (70°C-80°C) and low pH range (pH 4.0-7.0), is potentially valuable for various industrial applications. The end products of high efficient oat spelt xylan hydrolysis by XynNF (an endoxylanase) containing 95.8% xylooligosaccharides of 2-4 degree of polymerization (DP2-4) with the enrichment of xylobiose (61.5%) indicated that XynNF is a promising candidate for xylooligosaccharides production.

Character of cellulase activity in the guts of flagellate-free termites with different feeding habits.

Cellulose digestion in termites (Isoptera) is highly important for ecological reasons and applications in biofuel conversion. The speciose Termitidae family has lost flagellates in the hindgut and developed diverse feeding habits. To address the response of cellulase activity to the differentiation of feeding habits, a comparative study of the activity and distribution of composite cellulases, endo-ß-1,4-glucanase, and ß-glucosidase was performed in seven common flagellate-free termites with three feeding habits: the humus-feeding termites Sinocapritermes mushae (Oshima et Maki), Malaysiocapritermes zhangfengensis Zhu, Yang et Huang and Pericapritermes jiangtsekiangensis (Kemner); the fungus-growing termites Macrotermes barneyi Light and Odontotermes formosanus (Shiraki); and the wood-feeding termites Nasutitermes parvonasutus (Shiraki) and Havilanditermes orthonasus (Tsai et Chen). The results showed that in diverse feeding groups, the wood-feeding group had the highest total composite cellulase and endo-ß-1,4-glucanase activities, while the fungus-growing group had the highest ß-glucosidase activity. In terms of the distribution of cellulase activity in the alimentary canals, the cellulase activities in wood-feeding termites were concentrated in the midgut, but there was no significant difference between all gut segments in humus-feeding termites. As for the fungus-growing termites, the main site of composite cellulase activity was in the midgut. The endo-ß-1,4-glucanase activity was restricted to the midgut, but the primary site of ß-glucosidase activity was in the foregut and the midgut (Mac. barneyi). The functions of the gut segments apparently differentiated between feeding groups. The results suggest that the differentiation of feeding habits in flagellate-free termites was characterized by the distribution of cellulases in the gut rather than by variations in cellulase activity.