HIV-1 reactivation in HIV-latently infected dendritic cells by oral microorganisms and LPS

Dendritic cells are critical components of the host defense system that play pivotal role in linking innate immunity to adaptive immune responses. In the role of interfacing with pathogens through the action of surface pattern-recognition receptors, dendritic cells are a potential target for retroviral infection and latency. Dendritic cells are a long-lived reservoir of latent virus in HIV (human immunodeficiency virus)-infected patients. It is hypothesized that HIV-latently infected dendritic cells would be stimulated by oral bacteria leading to reactivation of HIV. In our HIV-latently infected dendritic cell models, of both promoter activation and HIV production, significant differences were observed among the bacterial species in their ability to stimulate HIV reactivation. The experimental data support the hypothesis that oral bacteria related to periodontal infections could trigger latently infected dendritic cells in gingival tissues and contribute to HIV recrudescence and undermining anti-retroviral therapy.     

Antimicrobial proline-rich peptides from the hemolymph of marine snail Rapana venosa

Hemolymph of Rapana venosa snails is a complex mixture of biochemically and pharmacologically active components such as peptides and proteins. Antimicrobial peptides are gaining attention as antimicrobial alternatives to chemical food preservatives and commonly used antibiotics. Therefore, for the first time we have explored the isolation, identification and characterisation of 11 novel antimicrobial peptides produced by the hemolymph of molluscs. The isolated peptides from the hemolymph applying ultrafiltration and reverse-phase high-performance liquid chromatography (RP-HPLC) have molecular weights between 3000 and 9500 Da, determined by mass spectrometric analysis. The N-terminal sequences of the peptides identified by Edman degradation matched no peptides in the MASCOT search database, indicating novel proline-rich peptides. UV spectra revealed that these substances possessed the characteristics of protein peptides with acidic isoelectric points. However, no Cotton effects were observed between 190 and 280 nm by circular dichroism spectroscopy. Four of the Pro-rich peptides also showed strong antimicrobial activities against tested microorganisms including Gram-positive and Gram-negative bacteria.     

Inhibitory effect of oral Lactobacillus against oral pathogens

Aims: To determine the inhibitory effect of oral Lactobacillus against putative oral pathogens. Methods and Results: Total 357 strains comprising 10 species of oral Lactobacillus, Lactobacillus fermentum (195), Lactobacillus salivarius (53), Lactobacillus casei (20), Lactobacillus gasseri (18), Lactobacillus rhamnosus (14), Lactobacillus paracasei (12), Lactobacillus mucosae (12), Lactobacillus oris (12), Lactobacillus plantarum (11) and Lactobacillus vaginalis (10) were used as producer strains. Inhibitory effect against a panel of indicators, periodontitis‐ and caries‐related pathogens, was assessed. Most oral Lactobacillus was able to inhibit the growth of both periodontitis‐ and caries‐related pathogens. The strongest inhibitory activity was associated with Lact. paracasei, Lact. plantarum, Lact. rhamnosus, Lact. casei and Lact. salivarius. Lactobacillus SD1–SD6, representing the six species with the strong inhibitory effect, inhibited growth of Streptococcus mutans ATCC 25175 in the biofilm model. Also, it was demonstrated that growth of Strep. mutans was inhibited in a mixture with Lact. paracasei SD1. The inhibition was enhanced in acidic condition and 5% glucose. Conclusions: The results have shown that oral Lactobacillus SD1–SD6 showed a strong inhibitory effect against Strep. mutans and Streptococcus sobrinus, as well as, Gram‐negative periodontal pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Significance and Impact of the Study: The results indicated that Lactobacillus may be of benefit as probiotics for the prevention of oral diseases.     

Microbiological and toxicological quality of dried herbs

Aims: The microbiological and toxicological quality of 51 samples of dried herbs (Melissa officinalis, Salvia officinalis, Malva sylvestris, Matricaria chamomilla, Alchemilla vulgaris and Centaurea cyanus) cultivated in family‐managed farms in Molise Region (Italy) was evaluated. Methods and Results: All the samples were analysed by using conventional methods, and for samples preparation, an alternative Washing and Shaking (WaS) protocol was developed to reduce release of antimicrobial compounds. None of the samples were of unsatisfactory quality with respect to aflatoxin B1, and only three samples from Malva sylvestris exceeded the limit of total aflatoxins according to Recommendation 2004/24/EC. The International Commission on Microbiological Specifications for Foods limits for mesophilic bacteria and total coliforms were exceeded in the 29·4 and 3·9% of samples, respectively: 7·8% of samples also exceeded the limit for Escherichia coli established by European Spice Association. When the ‘WaS’ method was used, higher microbial counts were obtained, especially for A. vulgaris, S. officinalis and M. officinalis. Conclusions: Herbs cultivated in family‐managed small agricultural areas showed a good microbiological and toxicological quality, irrespectively of preliminary washing or selection procedures. Significance and Impact of the Study: Herb matrices may contain antimicrobial activity which should be considered when applying the conventional microbiological methods for sample preparation. Alternative preparation protocols may have advantages to reduce antimicrobial effects and should be further evaluated.     

宏基因组学与动物病原微生物检测

宏基因组学（ metagenome）是直接从土壤、海水、人及动物胃肠道、口腔、呼吸道、皮肤等环境中获取样品DNA,利用载体将其克隆到替代宿主细胞中构建宏基因文库,以高通量检测为主要技术来研究特定环境中全部微生物的基因组及筛选活性物质和基因的新兴学科。利用宏基因组学技术不仅能够有效地检测特定环境的微生物群落结构,扩展了微生物资源的利用空间,发展了新兴的高通量检测技术,丰富了生物信息学内容。基于宏基因组学研究方法在环境微生物研究中的优势,对近年来相关领域、方法及其在人及动物病原微生物研究中的应用进行综述,以期将此方法用于实验动物病原微生物的调查分析及动物疫情、生物安全的监测。     

Distribution of Enteric Pathogens in Wastewater Secondary Effluent and Safety Analysis for Urban Water Reuse

Through a 1-year monitoring of enteroviruses and pathogenic bacteria in the secondary effluent using real-time polymerase chain reaction (real-time PCR), the pathogen removal requirement was evaluated for safeguarding the reclaimed water quality for urban reuse. The distribution of each pathogen in the secondary effluent was found to follow a log-normal relationship, although 50% cumulative concentrations differed much from each other (1.4 GEC/L of infectious enteroviruses, 3.1 × 10² CFU/L of Salmonella typhi, 1.0 × 10³ CFU/L of Shigella, and 3.3 × 10⁵ CFU/L of Escherichia coli). By exposure analysis regarding two reuse scenarios (golf course irrigation and recreational impoundment), risks were analyzed for pathogens in reused water based on monitoring data and dose–response relation. For enteroviruses and pathogenic bacteria, there were obvious differences in the relationship between the reliability and removal efficiency. Under an acceptable annual risk level (10^–4/a), the pathogen removal requirement depends on the manner of water reuse. In the golf course irrigation, the removal efficiency of enteroviruses, Salmonella typhi, Shigella, and Escherichia coli reach to 3.8～4.0-log, 1.4-log, 3.3-log, and 2.0-log, respectively, in order to ensure 95% reliability. However, if wastewater is reused for recreational impoundment, only a further increase around 1.5-log removal efficiency of pathogens can meet the requirement for the same reliability.     

Soft cheese supplemented with black cumin oil: Impact on food borne pathogens and quality during storage

Black cumin seed oil (BCSO) was tested for its inhibitory effect against some pathogenic bacteria (Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, Listeria monocytogenes Scott A and Salmonella enteritidis PT4) in Domiati cheese during cold storage. Physical, chemical and sensorial changes in cheese during storage were recorded. Pasteurized milk was inoculated before renneting with a mixed culture of bacteria at ca. 4 log CFU mL⁻¹. In vitro and in situ supplementation with BCSO showed antimicrobial impact on the growth of S. aureus, E. coli, L. monocytogenes and S. enteritidis inoculated into media and cheese samples. Supplementing of cheese with BCSO (0.1% or 0.2%, w/w) significantly reduced the counts of the inoculated pathogens by ca. 1.3 log and 1.5 log CFU g⁻¹ after 21 days of storage. In addition, BCSO controlled the development of titratable acidity, limited the changes in ripening indices, flavor components and kept considerable physicochemical and sensorial properties of cheese.