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2.
Forensic Sci Int Genet ; 71: 103045, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38615496

RESUMO

Identifying the sources of biosamples found at crime scenes is crucial for forensic investigations. Among the markers used for body fluid identification (BFI), mRNA has emerged as a well-studied marker because of its high specificity and remarkable stability. Despite this potential, commercially available mRNA kits specifically designed for BFI are lacking. Therefore, we developed an mRNA kit that includes 21 specific mRNA markers of body fluids, along with three housekeeping genes for BFI, to identify four forensic-relevant fluids (blood, semen, saliva, and vaginal fluids). In this study, we tested 451 single-body-fluid samples, validated the universality of the mRNA kit, and obtained a gene expression profile. We performed the validation studies in triplicates and determined the sensitivity, specificity, stability, precision, and repeatability of the mRNA kit. The sensitivity of the kit was found to be 0.1 ng. Our validation process involved the examination of 59 RNA mixtures, 60 body fluids mixtures, and 20 casework samples, which further established the reliability of the kit. Furthermore, we constructed five classifiers that can handle single-body fluids and mixtures using this kit. The classifiers output possibility values and identify the specific body fluids of interest. Our results showed the reliability and suitability of the BFI kit, and the Random Forest classifier performed the best, with 94% precision. In conclusion, we developed an mRNA kit for BFI which can be a promising tool for forensic practice.

3.
J Colloid Interface Sci ; 664: 228-237, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38461789

RESUMO

Ranging from industrial facilities to residential infrastructure, functional surfaces encompassing functionalities such as anti-fouling, fog collection, anti-corrosion, and anti-icing play a critical role in the daily lives of humans, but creating these surfaces is elusive. Bionic dewetting and liquid-infused surfaces have inspired the exploitation of functional surfaces. However, practical applications of these existing surfaces remain challenging because of their inherent shortcomings. In this study, we propose a novel functional slippery lubricated coating (FSLC) based on a simple blend of polysilazane (PSZ), silicone oil, and nano silica. This simple, nonfluorine based, and low-cost protocol promotes not only hierarchical micro-nano structure but also favorable surface chemistry, which facilitates robust silicone oil adhesion and excellent slippery properties (sliding angle: ∼1.6°) on various solid materials without extra processing or redundant treatments. The highly integrated competence of FSLC, characterized by robustness, durability, strong adhesion to substrates, and the ability for large-area preparation, render them ideal for practical production and application. The proposed FSLC holds outstanding application potentials for anti-fouling, self-cleaning, fog collection, anti-corrosion, and anti-icing functionalities.

4.
Genes (Basel) ; 15(1)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38255006

RESUMO

When analyzing challenging samples, such as low-template DNA, analysts aim to maximize information while minimizing noise, often by adjusting the analytical threshold (AT) for optimal results. A potential approach involves calculating the AT based on the baseline signal distribution in electrophoresis results. This study investigates the impact of reagent kits, testing quarters, environmental conditions, and amplification cycles on baseline signals using historical records and experimental data on low-template DNA. Variations in these aspects contribute to differences in baseline signal patterns. Analysts should remain vigilant regarding routine instrument maintenance and reagent replacement, as these may affect baseline signals. Prompt analysis of baseline status and tailored adjustments to ATs under specific laboratory conditions are advised. A comparative analysis of published methods for calculating the optimal AT from a negative signal distribution highlighted the efficiency of utilizing baseline signals to enhance forensic genetic analysis, with the exception of extremely low-template samples and high-amplification cycles. Moreover, a user-friendly program for real-time analysis was developed, enabling prompt adjustments to ATs based on negative control profiles. In conclusion, this study provides insights into baseline signals, aiming to enhance genetic analysis accuracy across diverse laboratories. Practical recommendations are offered for optimizing ATs in forensic DNA analysis.


Assuntos
DNA , Laboratórios , DNA/genética
5.
Materials (Basel) ; 17(2)2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38276447

RESUMO

Laser processing is an efficient method for fabricating a superhydrophobic surface and has attracted much attention due to its multifunctionality. However, excessive laser processing, such as laser beam overlap and multiple scans, generates both a thick, brittle recast layer and a thin material thickness, thereby greatly reducing the mechanical strength of the substrate. In addition, there is no report on fabricating a superhydrophobic surface on a superalloy substrate whose application includes a self-cleaning property. This work proposes the fabrication of a superhydrophobic surface on a superalloy substrate with high mechanical strength by optimizing the laser processing parameters including laser power, scanning speed, line spacing, and number of scans. We found that the microstructures required by superhydrophobicity could be constructed with a single laser scan. which could guarantee a minimal loss of the mechanical strength. The fabricated superhydrophobic surface on the superalloy substrate exhibited excellent self-cleaning of carbon deposition, showing good application potential in the aero engine field.

6.
Electrophoresis ; 45(5-6): 463-473, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37946554

RESUMO

Next-generation sequencing (NGS) allows for better identification of insertion and deletion polymorphisms (InDels) and their combination with adjacent single nucleotide polymorphisms (SNPs) to form compound markers. These markers can improve the polymorphism of microhaplotypes (MHs) within the same length range, and thus, boost the efficiency of DNA mixture analysis. In this study, we screened InDels and SNPs across the whole genome and selected highly polymorphic markers composed of InDels and/or SNPs within 300 bp. Further, we successfully developed and evaluated an NGS-based panel comprising 55 loci, of which 24 were composed of both SNPs and InDels. Analysis of 124 unrelated Southern Han Chinese revealed an average effective number of alleles (Ae ) of 7.52 for this panel. The cumulative power of discrimination and cumulative probability of exclusion values of the 55 loci were 1-2.37 × 10-73 and 1-1.19 × 10-28 , respectively. Additionally, this panel exhibited high allele detection rates of over 97% in each of the 21 artificial mixtures involving from two to six contributors at different mixing ratios. We used EuroForMix to calculate the likelihood ratio (LR) and evaluate the evidence strength provided by this panel, and it could assess evidence strength with LR, distinguishing real and noncontributors. In conclusion, our panel holds great potential for detecting and analyzing DNA mixtures in forensic applications, with the capability to enhance routine mixture analysis.


Assuntos
Impressões Digitais de DNA , Polimorfismo de Nucleotídeo Único , Humanos , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA , DNA/genética , DNA/análise , Sequenciamento de Nucleotídeos em Larga Escala , Frequência do Gene
7.
Materials (Basel) ; 16(23)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38068215

RESUMO

Superhydrophobic nickel surfaces have significant advantages in the field of corrosion protection compared with traditional nickel corrosion protection methods which need a toxic chemical corrosion inhibitor. Electrochemical etching, an ideal method for fabricating superhydrophobic nickel surfaces, was also limited by low current density, resulting in low processing efficiency. To overcome this limitation, we proposed a new method to fabricate a superhydrophobic nickel surface using a wire electrochemical etching method. The wire electrochemical etching method accomplished the etching process by sweeping a controlled wire cathode across the surface of the anode nickel plate in an environmentally friendly neutral electrolyte, NaCl. The superhydrophobic nickel sample with a contact angle of 153° and a rolling angle of 10° could be fabricated by wire electrochemical etching and modification. Additionally, the optimal parameters of the wire electrochemical etching and the principle of superhydrophobic surface formation had also been systematically investigated, respectively. Moreover, the superhydrophobic nickel surface had self-cleaning performance, antifouling performance, corrosion protection, and abrasion resistance. Wire electrochemical etching improves the current density of processing, which means that this method improves the processing efficiency for fabricating a superhydrophobic nickel surface. This work is expected to enrich the theory and technology for fabricating superhydrophobic nickel surfaces to improve the corrosion protection of nickel.

8.
Clin Lab ; 69(11)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37948474

RESUMO

BACKGROUND: This article reports on a young male with respiratory symptoms as the first presentation. METHODS: We identified the suspected pathogen by microscopic examination of blood smears, which was subsequently confirmed by blood culture. RESULTS: The patient was confirmed to be infected with Talaromyces marneffei, and further testing revealed that he was a patient with HIV co-infected with syphilis. CONCLUSIONS: With heavy fungemia the organisms may be seen on the peripheral blood smear, which can facilitate prompt diagnosis and treatment.


Assuntos
Coinfecção , Infecções por HIV , Sífilis , Talaromyces , Humanos , Masculino , Infecções por HIV/complicações , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Antifúngicos/uso terapêutico
9.
Langmuir ; 39(38): 13441-13448, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37657482

RESUMO

Titanium and its alloys have become the most excellent structure materials for naval seawater pipelines due to their high strength and good corrosion resistance. However, marine biofouling poses a serious threat to titanium alloy piping systems because of their good biocompatibility. Recently, the biomimetic antifouling coating, a novel antifouling method, has received great attention. Here, based on this biomimetic idea, we develop a nontoxic antifouling slippery surface (AFSS) using silicone oil, silane coupling agent, nanosilica, nanoceramic coating, epoxy resin, and capsaicin. The developed AFSS has excellent slippery performance for various droplets, good durability, and a superior self-cleaning property. Additionally, the antifouling performance of the AFSS was significantly enhanced, as confirmed by the reduced adhesion of proteins (70.7%), bacteria (97.2%), and algae (97.7%) compared to the ordinary titanium alloy. With these excellent properties, the AFSS was expected to be a promising candidate for protecting titanium alloy piping systems from marine biofouling.

10.
Front Immunol ; 14: 1188308, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37545497

RESUMO

Objective: This study was aimed to evaluate the efficacy and safety of transarterial chemoembolization combined with tyrosine kinase inhibitors and camrelizumab in the treatment of unresectable hepatocellular carcinoma and to explore a new therapeutic strategy for the treatment of advanced HCC. Patients and methods: A total of 87 patients aged 18-75 years with at least one measurable lesion per Response Evaluation Criteria in Solid Tumors (version 1.1) were included in the study. TACE was administered as needed, and camrelizumab and TKI medication were initiated within two weeks and one week after TACE, respectively. The primary endpoints were progression-free survival and objective response rate. Results: The 87 patients in this trial were last evaluated on September 28, 2022, and 35.8% were still receiving treatment at the data cutoff. A total of 34 patients (39.1%) died, and the median OS was not reached. The median PFS was 10.5 months (95% CI: 7.8-13.1). The ORR rate was 71.3% (62/87), and the DCR rate was 89.7% (78/87) per mRECIST. According to RECIST version 1.1, the ORR rate was 35.6% (31/87), and the DCR rate was 87.4% (76/87). Ten patients (11.5%) successfully underwent conversion therapy and all achieved R0 resection. Two patients achieved a complete pathological response, four achieved a major pathological response, and four had a partial response. All treatment-related adverse events were tolerated. No serious adverse events were observed, and no treatment-related deaths occurred. Conclusions: TACE combined with TKI and camrelizumab was safe and effective in treating advanced HCC. Triple therapy may benefit patients with large tumor burden and portal vein cancer thrombus and is expected to provide a new treatment strategy for advanced HCC. Clinical Trial Registration: ClinicalTrials.gov, identifier ChiCTR2000039508.


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/efeitos adversos , Neoplasias Hepáticas/terapia
11.
Materials (Basel) ; 16(15)2023 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-37569936

RESUMO

Passive-cooling building materials can achieve cooling without external energy consumption, which is an energy-saving and environmentally friendly cooling method. However, the existing passive-cooling building materials have the limitations of high cost, complicated processes, and a toxic organic solvent, which hinders the passive-cooling technology applied in practical building. To overcome these limitations, we developed a facile, high-efficiency, non-toxic, and superhydrophobic passive-cooling building coating (SPCBC) with an efficient cooling capability and excellent durability that was composed of polydimethylsiloxane and SiO2. The fabricated SPCBC demonstrated a high reflectance and a high emittance, showing a superior cooling capability with a 14 °C temperature drop compared with a bare cement surface on a hot summer day. In addition, the SPCBC could not be wetted or contaminated by muddy water, corrosive aqueous solutions, or dust, which presented an excellent anti-fouling and self-cleaning capability. Moreover, the fabricated SPCBC could work outdoors for 30 days, withstand UV irradiation for 30 days, and resist accelerated aging for 100 h without any significant changes in the superhydrophobicity and the cooling capability, meaning that the SPCBC had an outstanding durability. This work provides a new method to facilitate passive-cooling technology to apply in practical building in hot weather regions of the world.

12.
Chemosphere ; 335: 139154, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37290502

RESUMO

Diflubenzuron has been applied in agriculture and aquaculture, and its residues in ecological environment and food chain could result in chronic exposure and long-term toxicity effects for human health. However, limited information is available regarding diflubenzuron levels in fish and associated risk assessment. This study performed the analysis for dynamic bioaccumulation and elimination distribution of diflubenzuron in carp tissues. The results indicated that diflubenzuron was absorbed and enriched by fish body along with higher enrichment in lipid-rich tissues of fish. The peak concentration in carp muscle reached 6-fold of diflubenzuron concentration in aquaculture water. The median lethal concentration (LC50) of diflubenzuron at 96 h was 12.29 mg/L, presented low toxicity to carp. Risk assessment results showed that the chronic risk from dietary exposure to diflubenzuron through carp consumption for Chinese residents of children and adolescents, adults and elderly people were acceptable, while posed a certain risk for young children. This study provided the reference for pollution control, risk assessment and scientific management of diflubenzuron.


Assuntos
Carpas , Diflubenzuron , Poluentes Químicos da Água , Animais , Criança , Humanos , Idoso , Pré-Escolar , Adolescente , Diflubenzuron/toxicidade , Poluentes Químicos da Água/toxicidade , Bioacumulação , Poluição Ambiental
13.
Nanoscale ; 15(27): 11473-11481, 2023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37387274

RESUMO

Spontaneous and directional water transportation (SDWT) is considered as an ideal water transportation method and has a great prospect in the aerospace and ship fields. Nonetheless, the existing SDWT has the limitation of a slow water transportation velocity because of its geometry structure configuration, which hinders the practical application of the SDWT. To overcome this limitation, we developed a new superhydrophilic serial cycloid-shaped pattern (SSCP) which was inspired by the micro-cavity shape of the Nepenthes. First, we experimentally found that the water transportation velocity on the SSCP was faster than that on the superhydrophilic serial wedge-shaped pattern (SSWP) and analyzed the faster water transportation mechanism. Then, the influence of the SSCP parameters on the transportation velocity was investigated by a single-factor experiment. In addition, the water transportation velocity on the SSCP was enhanced to 289 mm s-1 by combining the single-factor experiment, orthogonal optimization design, streamline junction transition optimization, and pre-wet pattern, which was the fastest in the SDWT. Moreover, the SSCP demonstrated its superior capability in long-distance water transportation, gravity resistant water transportation, heat transfer, and fog collection. This finding shows remarkable application prospects in the high-performance fluid transportation system.

14.
Small ; 19(36): e2301745, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37156743

RESUMO

Freshwater scarcity crisis threatens human life and economic security. Collecting water from the fog seems to be an effective method to defuse this crisis. Nonetheless, the existing fog collection methods have the limitations of the low fog collection rate and efficiency because of their gravity-based droplet shedding. Here, the aforementioned limitations are resolved by proposing a new fog collection method based on the self-driven jet phenomenon of the mini fog droplets. A prototype fog collector (PFC) composed of a square container that is filled with water is first designed. Both sides of the PFC are superhydrophobic but covered with superhydrophilic pore array. The mini fog droplets touching the side wall are easily captured and spontaneously and rapidly penetrate into the pores to form jellyfish-like jets, which greatly increases the droplet shedding frequency, guaranteeing a higher fog collection rate and efficiency compared with the existing fog collection methods. Based on this, a more practical super-fast fog collector is finally successfully designed and fabricated which is assembled by several PFCs. This work is hoping to resolve the water crisis in some arid but foggy regions.

15.
Ther Clin Risk Manag ; 19: 329-339, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37041973

RESUMO

Purpose: This study aimed to evaluate the safety and efficacy of a combination of programmed death-1 (PD-1) inhibitor and regorafenib as second-line treatment for advanced hepatocellular carcinoma (HCC). Patients and Methods: We retrospectively analyzed the data of 38 patients with unresectable HCC who were treated with PD-1 inhibitor in combination with regorafenib as a second⁃line therapy as well as the data of 32 patients treated with regorafenib only therapy as a control. The clinical data, previous treatment strategies, follow-up imaging results, and adverse events during follow-ups were recorded. The mRECIST Criteria were used to evaluate the treatment outcome of intrahepatic lesions, and the Kaplan-Meier method was used to evaluate survival time. Results: Up to the last follow-up, the rego-PD-1 group had higher objective response rate (39.5% vs 15.6%, P = 0.028), longer progression-free survival (median 5.9 vs 4.6 months; P = 0.044), and better overall survival (OS) (median 14.5 vs 9.5 months; P = 0.041) than the regorafenib only group. Among the 38 patients in rego-PD-1 group, 1 patient (2.7%) achieved complete response, 14 patients (36.8%) achieved partial response, 14 patients (36.8%) achieved stable disease, and 9 patients (23.7%) achieved progressive disease. Among the 32 patients in regorafenib alone, 5 (15.6%) achieved partial response, 12 (37.5%) achieved stable disease, and 15 (46.9%) achieved progressive disease. Regorafenib alone, Child-Pugh B, and tumors >3 were independent prognostic factors for poor OS. The difference in the incidence of grade 3/4 adverse events between the two groups was not statistically significant (36.8% vs 28.1%; P = 0.439). Grade ≥3 treatment-related adverse events included hypertension and diarrhea. Conclusion: PD-1 inhibitor combined with regorafenib is a promising regimen in treating patients with unresectable HCC owing to its safety and effectiveness as well as low incidence of serious adverse events with its use.

16.
J Hazard Mater ; 443(Pt A): 130197, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36272371

RESUMO

The widespread use of the herbicide chlorimuron-methyl is hazard to rotational crops and causes soil degradation problems. Biodegradation is considered a promising way for removing herbicide residues from the environment. Here, a new isolated strain, Cedecea sp. LAM2020, enabled complete degradation of 100 mg/L chlorimuron-methyl within five days. Transcriptome analysis revealed that ABC transporters, atrazine degradation and purine metabolism were enriched in the KEGG pathway. Integrating GO and KEGG classification with related reports, we predict that carboxylesterases are involved in the biodegradation of chlorimuron-methyl by LAM2020. Heterologous expression of the carboxylesterase gene carH showed 26.67% degradation of 50 mg/L chlorimuron-methyl within 6 h. The intracellular potential biological response and extracellular degradation process of chlorimuron-ethyl were analyzed by the nontarget metabolomic and mass spectrometry respectively, and the biodegradation characteristics and complete mineralization pathway was revealed. The cleavage of the sulfonylurea bridge and the ester bond achieved the first step in the degradation of chlorimuron-methyl. Together, these results reveal the presence of acidolysis and enzymatic degradation of chlorimuron-methyl by strain LAM2020. Hydroponic corn experiment showed that the addition of strain LAM2020 alleviated the toxic effects of chlorimuron-ethyl on the plants. Collectively, strain LAM2020 may be a promising microbial agent for plants chlorimuron-ethyl detoxification and soil biofertilizer.


Assuntos
Herbicidas , Poluentes do Solo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Compostos de Sulfonilureia/metabolismo , Herbicidas/metabolismo , Enterobacteriaceae/metabolismo , Solo
17.
Chem Soc Rev ; 51(20): 8476-8583, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36189687

RESUMO

Liquid-repellent surfaces, such as superhydrophobic surfaces, superoleophobic surfaces, and slippery liquid-infused surfaces, have drawn keen research interest from the communities engaged in chemical synthesis, interfacial chemistry, surface engineering, bionic manufacturing and micro-nano machining. This is due to their great potential applications in liquid-proofing, self-cleaning, chemical resistance, anti-icing, water/oil remediation, biomedicine, etc. However, poor robustness and durability that notably hinders the real-world applications of such surfaces remains their Achilles heel. The past few years have witnessed rapidly increasing publications that address the robustness and durability of liquid-repellent surfaces, and many breakthroughs have been achieved. This review provides an overview of the recent progress made towards robust and durable liquid-repellent surfaces. First, we discuss the wetting of solid surface and its generally-adopted characterisation methods, and introduce typical liquid-repellent surfaces. Second, we focus on various evaluation methods of the robustness and durability of liquid-repellent surfaces. Third, the recent advances in design and fabrication of robust and durable liquid-repellent surfaces are reviewed in detail. Fourth, we present the applications where these surfaces have been employed in fields like chemistry, engineering, biology and in daily life. Finally, we discuss the possible research perspectives in robust and durable liquid-repellent surfaces. By presenting such state-of-the-art of this significant and fast-developing area, we believe that this review will inspire multidisciplinary scientific communities and industrial circles to develop novel liquid-repellent surfaces that can meet the requirements of various real-world applications.


Assuntos
Água , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície , Água/química , Molhabilidade
18.
Environ Pollut ; 307: 119477, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35598816

RESUMO

This study aims to investigate the effects of long-term nicosulfuron residue on an herbicide factory ecosystem. High-throughput sequencing was used to investigate the environmental microbial community structure and interactions. The results showed that the main contributor to the differences in the microbial community structure was the sample type, followed by oxygen content, pH and nicosulfuron residue concentration. Regardless of the presence or absence of nicosulfuron, soil, sludge, and sewage were dominated by groups of Bacteroidetes, Actinobacteria, and Proteobacteria. Long-term exposure to nicosulfuron increased alpha diversity of bacteria and archaea but significantly decreased the abundance of Bacteroidetes and Acidobateria compared to soils without nicosulfuron residue. A total of 81 possible nicosulfuron-degrading bacterial genera, e.g., Rhodococcus, Chryseobacterium, Thermomonas, Stenotrophomonas, and Bacillus, were isolated from the nicosulfuron factory environmental samples through culturomics. The co-occurrence network analysis indicated that the keystone taxa were Rhodococcus, Stenotrophomonas, Nitrospira, Terrimonas, and Nitrosomonadaceae_MND1. The strong ecological relationship between microorganisms with the same network module was related to anaerobic respiration, the carbon and nitrogen cycle, and the degradation of environmental contaminants. Synthetic community (SynCom), which provides an effective top-down approach for the critical degradation strains obtained, enhanced the degradation efficiency of nicosulfuron. The results indicated that Rhodococcus sp. was the key genus in the environment of long-term nicosulfuron exposure.


Assuntos
Herbicidas , Microbiota , Bactérias/metabolismo , Bacteroidetes/metabolismo , Herbicidas/metabolismo , Herbicidas/toxicidade , Piridinas , Esgotos , Solo/química , Microbiologia do Solo , Compostos de Sulfonilureia/metabolismo , Compostos de Sulfonilureia/toxicidade
19.
Microorganisms ; 9(12)2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34946147

RESUMO

Lactic acid bacteria (LAB) are commonly applied to fish as a means of growth promotion and disease prevention. However, evidence regarding whether LAB colonize the gastrointestinal (GI) tract of fish remains sparse and controversial. Here, we investigated whether Lacticaseibacillus casei ATCC 393 (Lc) can colonize the GI tract of crucian carp. Sterile feed irradiated with 60Co was used to eliminate the influence of microbes, and 100% rearing water was renewed at 5-day intervals to reduce the fecal-oral circulation of microbes. The experiment lasted 47 days and was divided into three stages: the baseline period (21 days), the administration period (7 days: day -6 to 0) and the post-administration period (day 1 to 19). Control groups were fed a sterile basal diet during the whole experimental period, whereas treatment groups were fed with a mixed diet containing Lc (1 × 107 cfu/g) and spore of Geobacillus stearothermophilus (Gs, 1 × 107 cfu/g) during the administration period and a sterile basal diet during the baseline and post-administration periods. An improved and highly sensitive selective culture method (SCM) was employed in combination with a transit marker (a Gs spore) to monitor the elimination of Lc in the GI tract. The results showed that Lc (<2 cfu/gastrointestine) could not be detected in any of the fish sampled from the treatment group 7 days after the cessation of the mixed diet, whereas Gs could still be detected in seven out of nine fish at day 11 and could not be detected at all at day 15. Therefore, the elimination speed of Lc was faster than that of the transit marker. Furthermore, high-throughput sequencing analysis combined with SCM was used to reconfirm the elimination kinetics of Lc in the GI tract. The results show that the Lc in the crucian carp GI tract, despite being retained at low relative abundance from day 7 (0.11% ± 0.03%) to 21, was not viable. The experiments indicate that Lc ATCC 393 cannot colonize the GI tract of crucian carp, and the improved selective culture in combination with a transit marker represents a good method for studying LAB colonization of fish.

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