[Study on the features of Clostridioides difficile infection among diarrhea patients in Kunming from 2018 to 2020]

Objective: We analyze the characteristics of Clostridioides difficile (C. difficile) infection among diarrhea patients in Kunming from 2018 to 2020 and provide evidence for follow-up surveillance and prevention. Methods: A total of 388 fecal samples of diarrhea patients from four sentinel hospitals in Yunnan Province from 2018 to 2020 were collected. Real-time quantitative PCR was used to detect the fecal toxin genes of C. difficile. The positive fecal samples isolated the bacteria, and isolates were identified by mass spectrometry. The genomic DNA of the strains was extracted for multi-locus sequence typing (MLST). The fecal toxin, strain isolation, and clinical patient characteristics, including co-infection with other pathogens, were analyzed. Results: Among the 388 fecal samples, 47 samples with positive reference genes of C. difficile were positive, with a total positive rate of 12.11%. There were 4 (8.51%) non-toxigenic and 43 (91.49%) toxigenic ones. A total of 18 strains C. difficile were isolated from 47 positive specimens, and the isolation rate of positive specimens was 38.30%. Among them, 14 strains were positive for tcdA, tcdB, tcdC, tcdR, and tcdE. All 18 strains of C. difficile were negative for binary toxins. The MLST results showed 10 sequence types (ST), including 5 strains of ST37, accounting for 27.78%; 2 strains of ST129, ST3, ST54, and ST2, respectively; and 1 strain of ST35, ST532, ST48, ST27, and ST39, respectively. Fecal toxin gene positive (tcdB+) results were statistically associated with the patient's age group and with or without fever before the visit; positive isolates were only statistically associated with the patient's age group. In addition, some C. difficile patients have co-infection with other diarrhea-related viruses. Conclusions: The infection of C. difficile in diarrhea patients in Kunming is mostly toxigenic strains, and the high diversity of strains was identified using the MLST method. Therefore, the surveillance and prevention of C. difficile should be strengthened.

[Change of innate lymphoid cell subsets in peripheral bloods and ascites in liver cirrhotic patients complicated with spontaneous bacterial peritonitis]

Objective: To investigate the change of innate lymphoid cells (ILC) subsets in peripheral blood and ascites in liver cirrhotic patients complicated with spontaneous bacterial peritonitis (SBP). Methods: The data of 62 patients with liver cirrhosis admited to the Zhumadian Central Hospital from November 2019 to November 2020 were analyzed. Among them, 41 cases were complicated with untainted ascites (untainted ascites group), while the other 21 cases were complicated with SBP (SBP group). Meanwhile, 20 cases of controls who received healthy examination in the same period were also enrolled (control group). Peripheral blood mononuclear cell (PBMC) was isolated from peripheral blood of all patients and controls. Mononuclear cell in ascites was isolated from patients with liver cirrhosis. The percentage of ILC1, ILC2, and ILC3 subsets in PBMC and mononuclear cell in ascites were measured by flow cytometry. CD3^-CD19^-CD20^-CD14^- cells (lin^-cells) were purified from ascites and were stimulated with lipopolysaccharide (LPS) for 24 h. The transcription factor T-bet, GATA3, and RORγt mRNA relative level in lin^-cells was semi-quantified by real-time PCR. Cytokine level in the supernatants was measured by enzyme linked immunosorbent assay. Differences of ILC subsets in peripheral blood and ascites were compared among groups. Results: There were twenty-nine males and twelve females in untainted ascites group, aged M(Q₁,Q₃) 49(33, 78) years. There were twelve males and nine females in SBP group, aged 50(37, 76) years. There were eleven males and nine females in control group, aged 48(32, 69) years. lin^-CD45⁺CD161⁺CD127⁺ ILC cells could be detected in both peripheral blood and ascites. There was no significant difference in total ILC percentage within PBMC among untainted ascites group, SBP group, and control group (P=0.235). There was also no significant difference of total ILC percentage within mononuclear cells in ascites between untainted ascites group and SBP group (P=0.232). The differences were not statistically significant of peripheral CD117^-CRTh2^-ILC1, CRTh2⁺ILC2, or CD117⁺CRTh2^-ILC3 within peripheral ILC among untainted ascites group, SBP group, and control group (all P>0.05). ILC1 percentage in ascites was up-regulated in SBP group compared with untainted ascites group (35.69%±3.39% vs 26.40%±3.85%, P<0.001), while ILC2 in ascites was down-regulated in SBP group (36.83%±7.70% vs 48.35%±9.45%, P<0.001). There was no statistical difference in ILC3 percentage in ascites between the two groups (P=0.230). T-bet mRNA relative level and IFN-γ production by lin^- cells from ascites were elevated in response to LPS stimulation in SBP group compared with untainted ascites group (both P<0.001). GATA3 mRNA relative level and IL-5/IL-13 secretion by lin^-cells from ascites were reduced in SBP group compared with untainted ascites group (both P<0.05). There was no significant difference of RORγt mRNA relative level or IL-17/IL-22 expression between the two groups (both P>0.05). Conclusion: Peripheral ILC subsets do not change in liver cirrhosis patients with SBP. ILC1 percentage is up-regulated, and ILC2 percentage is down-regulated in ascites in liver cirrhosis patients with SBP.

[Roles of detection, surveillance and early warning on outbreaks or epidemics of infectious diseases]

Infectious diseases are still one of the leading causes of morbidity and death globally, affecting public health and life, social and economic development, and even national security. Early detection focuses on detecting the abnormal information of infectious disease outbreaks or epidemics in a timely and sensitive way to conduct field investigation and verification. It is also a precursor to effective surveillance and early warning system. The effective surveillance and early warning system can fully and accurately understand the real conditions, driving forces, and transmission chain of the occurrence of a specific infectious disease outbreak and epidemic and put forward scientific and effective prevention and control strategies and measures. Due to the measurement of the resources support and the particular data collection value, it is not easy to obtain epidemiological, etiological, and other data information in a timely, complete and accurate manner. This paper summarized the theory and technology on early detection, effective surveillance, and early warning information on infectious diseases. It also integrated and utilized the multi-source data, including effective infectious disease surveillance and the country's early warning system, to better understand the outbreak epidemic, causes, risks, processes, and driving forces. Thus, it is possible to set up a sensitive, specific staging measurement innovative technical system to monitor, early warning, and timely respond to acute infectious diseases through multidisciplinary cooperation in China. It provides the basis for strengthening the surveillance and early warning of new emerging and major infectious diseases and public health emergencies, avoiding the spread of inadequate response to infectious disease, and preventing the resources waste of over-response.

[Interpretation of group standard for Clostridioides difficile infection diagnosis]

Clostridioides difficile is a key pathogen of antibiotic related diarrhea and hospital associated infection, causing several outbreaks in Europe and North Americans and resulting in severe disease burden. However, the standardized diagnostic principle and detection specifications in C. difficile infection (CDI) survey are limited in China, and the infection rate and disease burden of CDI in China are unclear. Therefore, National Institute for Communicable Disease Control and Prevention,National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, together with another 11 institutions, draft the group standard entitled "Diagnosis of Clostridium difficile infection (T/CPMA 008-2020)" of Chinese Preventive Medicine Association. Based on the principle of "legality, scientificity, advancement, and feasibility", this standard clarifies risk factors, diagnosis principles, diagnoses and differential diagnoses in order to improve the accuracy of CDI diagnosis in clinical practice, guide the surveillance for CDI, and understand the infection rate and disease burden of CDI in China.

LXA4 protects against hypoxic-ischemic damage in neonatal rats by reducing the inflammatory response via the IκB/NF-κB pathway

Hypoxia and the resultant decreases in cerebral blood flow in the perinatal period can lead to neonatal hypoxic-ischemic (HI) brain injury, which can, in turn, cause severe disability or even death. However, the efficacy of current treatment strategies remains limited. Several studies have demonstrated that lipoxin A4 (LXA4), as one of the earliest types of endogenous lipid mediators, can inhibit the accumulation of neutrophils, arrest inflammation, and promote the resolution of inflammation. However, research on LXA4 in the nervous system has rarely been carried out. In the present study, we sought to investigate the protective effect of LXA4 on HI brain damage in neonatal rats, as well as the underlying mechanisms. Through experiments conducted using an HI animal model, we found that the LXA4 intervention promoted the recovery of neuronal function and tissue structure following brain injury while maintaining the integrity of the blood-brain barrier in addition to reducing cerebral edema, infarct volume, and inflammatory responses. Our results suggest that LXA4 interfered with neuronal oxygen-glucose deprivation insults, reduced the expression of inflammatory factors, inhibited apoptosis, and promoted neuronal survival in vitro. Finally, the LXA4 intervention attenuated HI-induced activation of inhibitor kappa B (IκB) and degradation of nuclear factor-κB (NF-κB). In conclusion, our data suggest that LXA4 exerts a neuroprotective effect against neonatal HI brain damage through the IκB/NF-κB pathway. Our findings will help inform future studies regarding the effects of LXA4 on neuroinflammation, blood-brain barrier integrity, and neuronal apoptosis.

Treatment With Liraglutide Exerts Neuroprotection After Hypoxic-Ischemic Brain Injury in Neonatal Rats via the PI3K/AKT/GSK3β Pathway

Neonatal hypoxic–ischemic (HI) brain injury is a detrimental disease, which results in high mortality and long-term neurological deficits. Nevertheless, the treatment options for this disease are limited. Thus, the aim of the present study was to assess the role of liraglutide in neonatal HI brain injury in rats and investigate the associated mechanisms. The results showed that treatment with liraglutide significantly reduced infarct volume and ameliorated cerebral edema, decreased inflammatory response, promoted the recovery of tissue structure, and improved prognosis following HI brain injury. Moreover, treatment with liraglutide inhibited apoptosis and promoted neuronal survival both in the rat model and following oxygen-glucose deprivation (OGD) insult. LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), partially reversed these therapeutic effects, suggesting that the PI3K/protein kinase B (Akt) pathway was involved. In conclusion, our data revealed that treatment with liraglutide exerts neuroprotection after neonatal HI brain injury via the PI3K/Akt/glycogen synthase kinase-3β (GSK3β) pathway and may be a promising therapy for this disease.

A dominant dendrite phenotype caused by the disease-associated G253D mutation in doublecortin (DCX) is not due to its endocytosis defect

Doublecortin (DCX) is a protein needed for cortical development, and DCX mutations cause cortical malformations in humans. The microtubule-binding activity of DCX is well-described and is important for its function, such as supporting neuronal migration and dendrite growth during development. Previous work showed that microtubule binding is not sufficient for DCX-mediated promotion of dendrite growth and that domains in DCX's C terminus are also required. The more C-terminal regions of DCX bind several other proteins, including the adhesion receptor neurofascin and clathrin adaptors. We recently identified a role for DCX in endocytosis of neurofascin. The disease-associated DCX-G253D mutant protein is known to be deficient in binding neurofascin, and we now asked if disruption of neurofascin endocytosis underlies the DCX-G253D-associated pathology. We first demonstrated that DCX functions in endocytosis as a complex with both the clathrin adaptor AP-2 and neurofascin: disrupting either clathrin adaptor binding (DCX-ALPA) or neurofascin binding (DCX-G253D) decreased neurofascin endocytosis in primary neurons. We then investigated a known function for DCX, namely, increasing dendrite growth in cultured neurons. Surprisingly, we found that the DCX-ALPA and DCX-G253D mutants yield distinct dendrite phenotypes. Unlike DCX-ALPA, DCX-G253D caused a dominant-negative dendrite growth phenotype. The endocytosis defect of DCX-G253D thus was separable from its detrimental effects on dendrite growth. We recently identified Dcx-R59H as a dominant allele and can now classify Dcx-G253D as a second Dcx allele that acts dominantly to cause pathology, but does so via a different mechanism.

Cloning and characterization of DELLA genes in Artemisia annua

Gibberellins (GA) are some of the most important phytohormones involved in plant development. DELLA proteins are negative regulators of GA signaling in many plants. In this study, the full-length cDNA sequences of three DELLA genes were cloned from Artemisia annua. Phylogenetic analysis revealed that AaDELLA1 and AaDELLA2 were located in the same cluster, but AaDELLA3 was not. Subcellular localization analysis suggested that AaDELLAs can be targeted to the nucleus and/or cytoplasm. Real-time PCR indicated that all three AaDELLA genes exhibited the highest expression in seeds. Expression of all AaDELLA genes was enhanced by exogenous MeJA treatment but inhibited by GA3 treatment. Yeast two-hybrid assay showed that AaDELLAs could interact with basic helix-loop-helix transcription factor AaMYC2, suggesting that GA and JA signaling may be involved in cross-talk via DELLA and MYC2 interaction in A. annua.

Cloning and characterization of the drought-resistance OsRCI2-5 gene in rice (Oryza sativa L.)

The genomic expression profile of the super-hybrid rice Liangyoupeijiu female parent Pei'ai 64S in different tissues at different developmental stages under low temperature, drought, and high temperature stresses were detected using an Affymetrix GeneChip Rice Genome Array to screen upregulated and downregulated genes. In this study, we screened the drought-resistant gene OsRCI2-5, after which a constitutive OsRCI2-5 construct was created and transferred into Nipponbare. After polyethylene glycol-6000 and drought treatment, we found that the OsRCI2-5 gene improved the drought resistance of Nipponbare. Gene expression profiling showed that the OsRCI2-5 gene was expressed in the rice leaves, stems, and flower organs. Subcellular localization revealed that the gene was located in the membranes, and hence, we can deduce that a membrane signal peptide was responsible for signal transduction.

Noise-like pulse in a gain-guided soliton fiber laser

We report on the operation of a passively mode-locked fiber ring laser made of purely positive dispersion fibers and mode-locked by using the nonlinear polarization rotation technique. It was experimentally found that apart from the gain-guided soliton operation the laser can also emit a kind of noise-like pulse. We show numerically that the noise-like pulse emission is caused by the peak power clamping effect of the laser cavity on the gain-guided soliton.