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Journal of the Science of Food and... Mar 2024Aquatic products are rich in nutrients and unique in flavor, and are popular among the public. However, aquatic products are extremely susceptible to quality degradation... (Review)
Review
Analysis of changes in volatile compounds and evolution in free fatty acids, free amino acids, nucleotides, and microbial diversity in tilapia (Oreochromis mossambicus) fillets during cold storage.
BACKGROUND
Aquatic products are rich in nutrients and unique in flavor, and are popular among the public. However, aquatic products are extremely susceptible to quality degradation during storage, of which odor deterioration is the most obvious and influential aspect. Odor deterioration in aquatic products is widespread and severely affects overall flavor and quality. In this study, odor deterioration and flavor-related quality degradation of tilapia during cold storage are discussed, focusing on the changes in volatile compounds and the evolution of free fatty acids (FFAs), free amino acids (FAAs), nucleotides, and microbial diversity.
RESULTS
A total of 63 volatile compounds were detected by gas chromatography-mass spectrometry, including 11 hydrocarbons, 10 alcohols, 6 aldehydes, 8 ketones, 6 esters, 9 aromatics, 3 phenols, and 10 other compounds. Microbial diversity analysis revealed that Acinetobacter, Psychrobacter, Vagococcus, and Myroides were the main dominant species of tilapia at the end of cold storage and predicted that microorganisms could influence the flavor of tilapia by participating in important metabolic pathways. Meanwhile, the evolution of FFAs, FAAs, and nucleotides also had a significant impact on odor deterioration, as evidenced by the contribution of unsaturated fatty acids (such as oleic acid and linoleic acid), Lys, and off-flavor nucleotides (HxR and Hx) to the undesirable flavor. Oxidation of oleic acid and linoleic acid resulted in changes in aldehydes, with Lys, HxR, and Hx being key flavor precursors and off-flavor contributors.
CONCLUSION
This study contributes to a comprehensive overview of odor deterioration and the evolution of flavor-related quality in tilapia during cold storage, providing new insights into the regulation of overall flavor and quality. © 2023 Society of Chemical Industry.
Topics: Animals; Food Storage; Fatty Acids, Nonesterified; Amino Acids; Tilapia; Aldehydes; Linoleic Acids; Oleic Acids; Volatile Organic Compounds
PubMed: 38050785
DOI: 10.1002/jsfa.13188 -
Journal of Zoo and Wildlife Medicine :... Mar 2024Between 2015 and 2019, a health screening was carried out annually on captive-bred snails prior to export for reintroduction as part of an international effort to...
Between 2015 and 2019, a health screening was carried out annually on captive-bred snails prior to export for reintroduction as part of an international effort to repopulate areas of French Polynesia, where the snails were extinct or critically endangered. In total, 129 separate tank populations of 12 different species were screened at ZSL London Zoo. Wet mounts and smears stained with modified Ziehl-Neelsen (MZN) of 535 fecal samples were examined, and 45% contained flagellated protozoa, and 35.5% had MZN-positive oocysts, measuring 3-5 µm in diameter. Smaller (2 µm) presumptive spores, MZN-positive bacilli, ciliated protozoa and nematodes were recorded less frequently. Fecal bacterial culture yielded mixed species, with a clear predominance of species (88.9% of samples). The MZN-positive oocysts (3-5 µm) were present in 6.5% of impression smears from the apices of 432 snails examined postmortem, plus acid-fast bacilli in a few cases, but no 2 µm spores. Mixed bacteria were cultured from coelomic swabs, with species again the most common (63.5%). Histologic examination was carried out on 292 snails. Autolysis affected almost 90% of those found dead but only 3.4% of euthanized snails. Histology commonly identified microsporidial sporocysts in the digestive gland and midgut epithelium of all but two species. Intracellular, extracytoplasmic -like organisms were also common in the midgut but were only observed when snails were fixed in 10% formalin (2017-2019), not ethanol. There were no clear pathologic changes associated with either organism. Pigmented hemocytic nodules were commonly observed, most frequently in the foot process; these were either age related or evidence of prior chronic inflammatory reaction and of low clinical significance. With no evidence of poor health and no significant organisms found, a total of 4,978 individuals representing 12 species were exported for reintroduction.
Topics: Animals; Cryptosporidium; Cryptosporidiosis; Bacteria; Feces; Microsporidia
PubMed: 38453485
DOI: 10.1638/2023-0077 -
BMJ Case Reports May 2024A middle-aged male patient presented with a central corneal perforation in a deep stromal infiltrate in his left eye. An emergency therapeutic penetrating keratoplasty...
A middle-aged male patient presented with a central corneal perforation in a deep stromal infiltrate in his left eye. An emergency therapeutic penetrating keratoplasty was performed. Microbiological evaluation of the corneal scraping specimen revealed septate fungal filaments on stains. However, culture reports after 24 hours from the scraping sample and the excised half corneal button showed growth of gram-negative bacilli. This pathogen was identified as an aerobic, non-fermentative, gram-negative, bacillus by conventional microbiology and confirmed as species by the VITEK 2 Compact system (bioMérieux, Marcy l'Etoile, France). Susceptibility to chloramphenicol was noted based on which the patient was treated with topical chloramphenicol 0.5%. No recurrence of the infection was noted. This is the first reported case of corneal infection with the species of bacteria which, heretofore, have been known to cause endocarditis and urinary tract infections.
Topics: Humans; Male; Middle Aged; Keratitis; Eye Infections, Fungal; Anti-Bacterial Agents; Keratoplasty, Penetrating; Chloramphenicol; Eye Infections, Bacterial; Corneal Perforation
PubMed: 38719269
DOI: 10.1136/bcr-2023-258474 -
Food Chemistry: X Jun 2024Microbial composition plays an important role in the quality and flavor of bacon. The aims of this study were to detect bacterial community succession using...
Microbial composition plays an important role in the quality and flavor of bacon. The aims of this study were to detect bacterial community succession using high-throughput sequencing (HTS) and volatile flavor compound changes using gas chromatography-ion mobility spectrometry (GC-IMS) during the production of Zhenba bacon. The results showed that a total of 70 volatile compounds were detected. Among them, ketones, hydrocarbons, aldehydes, esters and alcohols were the main substances in the curing and smoking stages. In addition, the fungal abundance was greater than the bacterial abundance, and there was obvious succession of the microbial community with changes in fermentation time and processing technology. The main functional bacterial genera in the curing and smoking stages were , and , and the main fungal genera were and . Through correlation analysis, we found that pyrrole, 2-pentanol, methyl isobutyl ketone (MIBK) and ethyl acetate (EA) were significantly correlated with , , and ( < 0.01), and it is speculated that they contribute significantly to flavor formation. The results of this study are helpful for understanding the microbial dynamics and characteristic volatile flavor compounds in Zhenba bacon, and provide new insights into the relationship between microorganisms and flavor through potential correlations.
PubMed: 38813459
DOI: 10.1016/j.fochx.2024.101478 -
Waste Management & Research : the... Sep 2023Black soldier fly larvae (BSFL) hold great promise for sustainable management of meat and bone meal (MBM), a kind of organic waste. Harvested BSFL frass can be used as...
Black soldier fly larvae (BSFL) hold great promise for sustainable management of meat and bone meal (MBM), a kind of organic waste. Harvested BSFL frass can be used as soil amendment or organic fertilizer. This study evaluated the quality and microbial profile in the frass of BSFL, fed with fish MBM containing 0% (CK), 1% (T1), 2% (T2) and 3% (T3) of rice straw. Results suggested straw addition into fish MBM had no significant impacts on BSFL weight; however, straw addition remarkably affected waste reduction and conversion efficiency, as well as physicochemical properties including electric conductivity, organic matter (OM) and total phosphorus contents in frass. Fourier transform infrared analysis indicated that increasing levels of cellulose and lignin might not be fully degraded or transformed by BSFL when more straw was introduced into substrates. Straw addition had hardly significant influences on microbial richness or evenness in BSFL frass, only T3 treatment remarkably elevated the phylogenetic diversity value more than the control. , , and were the most dominant phyla. Genera , and maintained high abundances in all frass samples. Elements including OM, pH and Na were key factors in shaping the microbiological characteristics of BSFL frass. Our findings helped to understand the effects of fish MBM waste manipulation on BSFL frass qualities and contributed to the further application of BSFL frass.
Topics: Animals; Larva; Phylogeny; Diptera; Meat
PubMed: 36951008
DOI: 10.1177/0734242X231160091 -
Case Reports in Infectious Diseases 2023is a Gram-negative opportunistic pathogen known to rarely cause a wide range of opportunistic infections in humans. We report a novel case of bacteremia in a...
is a Gram-negative opportunistic pathogen known to rarely cause a wide range of opportunistic infections in humans. We report a novel case of bacteremia in a paraplegic patient with an extensive medical history likely due to a tunneled dialysis catheter infection that was successfully treated with levofloxacin.
PubMed: 38020519
DOI: 10.1155/2023/3089837 -
Ecotoxicology and Environmental Safety Jan 2024Thiram, a typical fungicide pesticide, is widely used in agricultural production. The presence of thiram residues is not only due to over-utilization, but is also...
Thiram, a typical fungicide pesticide, is widely used in agricultural production. The presence of thiram residues is not only due to over-utilization, but is also primarily attributed to long-term accumulation. However, there is a paucity of information regarding the impact of prolonged utilization of thiram at low doses on the gut microbiota, particularly with respect to gut fungi. Our objective is to explore the effect of thiram on broilers from the perspective of gut microbiota, which includes both bacteria and fungi. We developed a long-term low-dose thiram model to simulate thiram residue and employed 16 S rRNA and ITS gene sequencing to investigate the diversity and profile of gut microbiota between group CC (normal diet) and TC (normal diet supplemented with 5 mg/kg thiram). The results revealed that low doses of thiram had a detrimental effect on broiler's growth performance, resulting in an approximate reduction of 669.33 g in their final body weight at day 45. Our findings indicated that low-dose thiram had a negative impact on the gut bacterial composition, leading to a notable reduction in the abundance of Merdibacter, Paenibacillus, Macrococcus, Fournierella, and Anaeroplasma (p < 0.05) compared to the CC group. Conversely, the relative level of Myroides was significantly increased (p < 0.05) in response to thiram exposure. In gut fungi, thiram significantly enhanced the diversity and richness of gut fungal populations (p < 0.05), as evidenced by the notable increase in alpha indices, i.e. ACE (CC: 346.49 ± 117.27 vs TC: 787.27 ± 379.14, p < 0.05), Chao 1 (CC: 317.63 ± 69.13 vs TC: 504.85 ± 104.50, p < 0.05), Shannon (CC: 1.28 ± 1.19 vs TC: 5.39 ± 2.66, p < 0.05), Simpson (CC: 0.21 ± 0.21 vs TC: 0.78 ± 0.34, p < 0.05). Furthermore, the abundance of Ascomycota, Kickxellomycota, and Glomeromycota were significantly increased (p < 0.05) by exposure to thiram, conversely, the level of Basidiomycota was decreased (p < 0.05) in the TC group compared to the CC group. Overall, this study demonstrated that low doses of thiram induced significant changes in the composition and abundance of gut microbiota in broilers, with more pronounced changes observed in the gut fungal community as compared to the gut bacterial community. Importantly, our findings further emphasize the potential risks associated with low dose thiram exposure and have revealed a novel discovery indicating that significant alterations in gut fungi may serve as the crucial factor contributing to the detrimental effects exerted by thiram residues.
Topics: Animals; Thiram; Chickens; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Fungicides, Industrial; Bacteria
PubMed: 38157796
DOI: 10.1016/j.ecoenv.2023.115879 -
Journal of Medical Entomology Jun 2024Insects and microorganisms, ubiquitous organisms in the natural world, have developed intricate relationships throughout their evolutionary histories. However, most...
Insects and microorganisms, ubiquitous organisms in the natural world, have developed intricate relationships throughout their evolutionary histories. However, most studies have concentrated on specific time points or life stages, but some limited studies have investigated the dynamics of microbial diversity within insects across life stages. Here, 16S rDNA sequencing technology was used to investigate the gut bacterial community across the life stages of Sarcophaga peregrina (Robineau-Desvoidy) (Diptera: Sarcophagidae). The results revealed that the gut bacterial diversity of S. peregrina varied with life stage and showed similarity in the nearby life stages. Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were the dominant phyla in S. peregrina. Genera such as Providencia, Ignatzschineria, and Myroides are implicated in potentially pivotal roles during the developmental processes of this flesh fly. Furthermore, the effects of amikacin on the growth and development of S. peregrina were not statistically significant. However, we did observe significant changes at the protein level, which suggests a close association between protein-level alterations and growth and development. Additionally, we speculate that S. peregrina regulates its nutritional status during nonfeeding stages to meet the demands of eclosion. This study represents the first comprehensive examination of the intestinal bacterial composition across various life stages of S. peregrina. Our findings deepen our understanding of the gut microbiota in this flesh fly and lay the groundwork for further exploration into the intricate interactions between microorganisms and insects.
PubMed: 38902886
DOI: 10.1093/jme/tjae071 -
Molecular Biology Reports May 2024Insect gut microbiomes play a fundamental role in various aspects of insect physiology, including digestion, nutrient metabolism, detoxification, immunity, growth and...
Contrasting gut bacteriomes unveiled between wild Antheraea assamensis Helfer (Lepidoptera: Saturniidae) and domesticated Bombyx mori L. (Lepidoptera: Bombycidae) silkworms.
BACKGROUND
Insect gut microbiomes play a fundamental role in various aspects of insect physiology, including digestion, nutrient metabolism, detoxification, immunity, growth and development. The wild Muga silkworm, Antheraea assamensis Helfer holds significant economic importance, as it produces golden silk.
METHODS AND RESULTS
In the current investigation, we deciphered its intricate gut bacteriome through high-throughput 16S rRNA amplicon sequencing. Further, to understand bacterial community dynamics among silkworms raised under outdoor environmental conditions, we compared its gut bacteriomes with those of the domesticated mulberry silkworm, Bombyx mori L. Most abundant bacterial phyla identified in the gut of A. assamensis were Proteobacteria (78.1%), Bacteroidetes (8.0%) and Firmicutes (6.6%), whereas the most-abundant phyla in B. mori were Firmicutes (49-86%) and Actinobacteria (10-36%). Further, Gammaproteobacteria (57.1%), Alphaproteobacteria (10.47%) and Betaproteobacteria (8.28%) were the dominant bacterial classes found in the gut of A. assamensis. The predominant bacterial families in A. assamensis gut were Enterobacteriaceae (27.7%), Comamonadaceae (9.13%), Pseudomonadaceae (9.08%) Flavobacteriaceae (7.59%) Moraxellaceae (7.38%) Alteromonadaceae (6.8%) and Enterococcaceae (4.46%). In B. mori, the most-abundant bacterial families were Peptostreptococcaceae, Enterococcaceae, Lactobacillaceae and Bifidobacteriaceae, though all showed great variability among the samples. The core gut bacteriome of A. assamensis consisted of Pseudomonas, Acinetobacter, Variovorax, Myroides, Alteromonas, Enterobacter, Enterococcus, Sphingomonas, Brevundimonas, Oleispira, Comamonas, Oleibacter Vagococcus, Aminobacter, Marinobacter, Cupriavidus, Aeromonas, and Bacillus. Comparative gut bacteriome analysis revealed a more complex gut bacterial diversity in wild A. assamensis silkworms than in domesticated B. mori silkworms, which contained a relatively simple gut bacteriome as estimated by OTU richness. Predictive functional profiling of the gut bacteriome suggested that gut bacteria in A. assamensis were associated with a wide range of physiological, nutritional, and metabolic functions, including biodegradation of xenobiotics, lipid, amino acid, carbohydrate metabolism, and biosynthesis of secondary metabolites and amino acids.
CONCLUSIONS
These results showed great differences in the composition and diversity of gut bacteria between the two silkworm species. Both insect species harbored core bacterial taxa commonly found in insects, but the relative abundance and composition of these taxa varied markedly.
Topics: Animals; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Bombyx; Bacteria; Phylogeny; Moths
PubMed: 38777963
DOI: 10.1007/s11033-024-09629-9 -
Frontiers in Microbiology 2024Chinese cabbage, scientifically known as subsp is a highly popular vegetable in China for its delectable taste. However, the occurrence of bacterial soft rot disease...
Chinese cabbage, scientifically known as subsp is a highly popular vegetable in China for its delectable taste. However, the occurrence of bacterial soft rot disease poses a significant threat to its growth and overall development. Consequently, this study aimed to explore the defense mechanisms employed by Chinese cabbage against bacterial soft rot disease. Specifically, the investigation focused on understanding the relationship between the disease and the microbial communities present in the soil surrounding the roots of Chinese cabbage. Significant disparities were observed in the composition of microbial communities present in the root-zone soil of healthy Chinese cabbage plants compared to those affected by -caused soft rot disease. The analysis of 16S rRNA gene high-throughput sequencing results revealed a lower abundance of Proteobacteria (8.39%), Acidobacteriot (0.85), (3.51%), and (1.48%), whereas Firmicutes (113.76%), Bacteroidota (8.71%), Chloroflexi (4.89%), Actinobacteriota (1.71%), A4b (15.52%), (1.62%), and (1.35%) were more prevalent in healthy plant soils. Similarly, the analysis of ITS gene high-throughput sequencing results indicated a reduced occurrence of Chytridiomycota (23.58%), Basidiomycota (21.80%), (86.22%), and (22.57%) in healthy soils. In comparison, Mortierellomycota (50.72%), Ascomycota (31.22%), (485.08%), and (51.59%) were more abundant in healthy plant soils. In addition, a total of 15 bacterial strains were isolated from the root-zone soil of diseased Chinese cabbage plants. These isolated strains demonstrated the ability to fix nitrogen (with the exception of ZT20, ZT26, ZT41, ZT45, and ZT61), produce siderophores and indole acetic acid (IAA), and solubilize phosphate. Notably, ZT14 (), ZT33 (), ZT41 (), ZT52 (), ZT58 (), ZT45 (), and ZT32 () exhibited significant growth-promoting effects as determined by the plant growth promotion (PGP) tests. Consequently, this investigation not only confirmed the presence of the soft rot pathogen in Chinese cabbage plants in Hangzhou, China, but also advanced our understanding of the defense mechanisms employed by Chinese cabbage to combat soft rot-induced stress. Additionally, it identified promising plant-growth-promoting microbes (PGPMs) that could be utilized in the future to enhance the Chinese cabbage industry.
PubMed: 38784798
DOI: 10.3389/fmicb.2024.1401896