Survival of Microencapsulated Lactococcus Lactis Subsp. Lactis R7 Applied in Different Food Matrices

Survival of Lactococcus lactis subsp. lactis R7 microencapsulated with whey and inulin was analyzed when applied in blueberry juice, milk and cream. For 28 days, cell viability was evaluated for storage (4°C), simulated gastrointestinal tract (GIT) and thermal resistance. All matrices described high cell concentration when submitted to GIT (11.74 and 12 log CFU.mL-1), except for blueberry juice. The thermal resistance analysis proved the need for microencapsulation, regardless of the food matrix. The results indicate that L. lactis R7 microcapsules have potential for application in different matrices and in the development of new probiotic products by thermal processing.

Analysis of the Parametric Correlation in Mathematical Modeling of In Vitro Glioblastoma Evolution Using Copulas

Modeling and simulation are essential tools for better understanding complex biological processes, such as cancer evolution. However, the resulting mathematical models are often highly non-linear and include many parameters, which, in many cases, are difficult to estimate and present strong correlations. Therefore, a proper parametric analysis is mandatory. Following a previous work in which we modeled the in vitro evolution of Glioblastoma Multiforme (GBM) under hypoxic conditions, we analyze and solve here the problem found of parametric correlation. With this aim, we develop a methodology based on copulas to approximate the multidimensional probability density function of the correlated parameters. Once the model is defined, we analyze the experimental setting to optimize the utility of each configuration in terms of gathered information. We prove that experimental configurations with oxygen gradient and high cell concentration have the highest utility when we want to separate correlated effects in our experimental design. We demonstrate that copulas are an adequate tool to analyze highly-correlated multiparametric mathematical models such as those appearing in Biology, with the added value of providing key information for the optimal design of experiments, reducing time and cost in in vivo and in vitro experimental campaigns, like those required in microfluidic models of GBM evolution.

Multicentric lymphoma in sheep (case report)

ABSTRACT The present study describes a case report in sheep with multicentric lymphoma. Clinical examination revealed the animal presented tachycardia, tachypnea, congested ocular mucous membranes, fever, cachexia, mild dehydration, decreased ruminal motility, difficulty in standing, and dysuria. Supportive treatment and complementary examination (complete blood count, radiography, ultrasound and abdominocentesis) were performed. The results showed neutrophilic leukocytosis, persistent lymphocytosis, exudate with high cell concentration, and imaging examination showed abundant fluid in the abdominal cavity, and enlarged iliac and mesenteric lymph nodes. Due to the severe clinical condition, the animal died and referred for necropsy. Samples from different organs were collected for histopathological analysis. At necropsy, abundant light brown exudate was observed in the thoracic and abdominal cavities, multiple white lobulated masses in different organs, in addition to pink, irregular, multifocal and coalescent nodules in the omentum, with neoplastic cells arranged in cords and cloak of cells supported by a thin fibrovascular stroma. Macroscopic and microscopic findings are characteristic of multicentric lymphoma.

Dean flow assisted single cell and bead encapsulation for high performance single cell expression profiling

Single-cell RNA sequencing examines the transcriptome of individual cells and reveals the inter-cell transcription heterogeneity, playing a critical role in both scientific research and clinical applications. Recently, droplet microfluidics-based platform for expression profiling has been shown as a powerful tool to capture of the transcriptional information on single cell level. Despite the breakthrough this platform brought about, it required the simultaneous encapsulation of single cell and single barcoded bead, the incidence of which was very low. Suboptimal capturing efficiency limited the throughput of the Drop-seq platform. In this work, we leveraged the advance in inertial microfluidics-based cell sorting and designed a microfluidic chip for high efficiency cell-bead co-encapsulation, increasing the capturing rate by more than four folds. Specifically, we adopted spiral and serpentine channels and ordered cells/beads before the encapsulation region. We characterized the effect of cell concentration on the capturing rate and achieved a cell-bead co-capturing rate up to 3%. We tested this platform by co-encapsulating barcoded beads and human-mouse cell mixtures. The sequencing data distinguished the majority of human and mice expressions, with the doublet rate being as low as 5.8%, indicating that the simultaneous capturing of two or more cells in one droplet was minimal even when using high cell concentration. This chip design showed great potential in improving the efficiency for future single cell expression profiling.

Semi-Continuous Reverse Membrane Bioreactor in Two-Stage Anaerobic Digestion of Citrus Waste

The presence of an antimicrobial compound called D-Limonene in citrus waste inhibits methane production from such waste in anaerobic digestion. In this work, a two-stage anaerobic digestion method is developed using reverse membrane bioreactors (rMBRs) containing cells encased in hydrophilic membranes. The purpose of encasement is to retain a high cell concentration inside the bioreactor. The effectiveness of rMBRs in reducing cell washout is evaluated. Three different system configurations, comprising rMBRs, freely suspended cells (FCs), and a combination of both (abbreviated to rMBR–FCs), are incubated at three different organic loading rates (OLRs) each, namely 0.6, 1.2, and 3.6 g COD/(L cycle). Incubation lasts for eight feeding cycles at 55 °C. Methane yield and biogas composition results show that rMBRs perform better than rMBR–FCs and FCs at all three OLRs. Volatile fatty acid profiles and H2 production show that the reactors are working properly and no upset occurs. Additionally, a short digestion time of 4 days can be achieved using the rMBR configuration in this study.

Optimization of liquid media and biosafety assessment for algae-lysing bacterium NP23

To control algal bloom caused by nutrient pollution, a wild-type algae-lysing bacterium was isolated from the Baiguishan reservoir in Henan province of China and identified as Enterobacter sp. strain NP23. Algal culture medium was optimized by applying a Placket–Burman design to obtain a high cell concentration of NP23. Three minerals (i.e., 0.6% KNO3, 0.001% MnSO4·H2O, and 0.3% K2HPO4) were found to be independent factors critical for obtaining the highest cell concentration of 1013 CFU/mL, which was 104 times that of the control. In the algae-lysing experiment, the strain exhibited a high lysis rate for the 4 algae test species, namely, Chlorella vulgari, Scenedesmus, Microcystis wesenbergii, and Chlorella pyrenoidosa. Acute toxicity and mutagenicity tests showed that the bacterium NP23 had no toxic and mutagenic effects on fish, even in large doses such as 107 or 109 CFU/mL. Thus, Enterobacter sp. strain NP23 has strong potential application in the microbial algae-lysing project.

Establishment of Fermentation Cultivation System to Produce PHB Using Methane-Utilizing Mixed Culture

A new fermentation strategy, one-step fermentation was developed for PHB production with high cell concentration and good productivity in a simplified way. Combined with the research results of PHB synthesis with the method of shake-flasks fermentation cultivation, the fermentation system was built based on the characteristics of fermentation tank cultivation,which was much superior to the traditional two-step fermentation. Based on shake flask studies, the full advantages of fermentation culture was taken to achieve the improvement of PHB production. Through this fermentation method with high PHB accumulation capacity, it provides a feasible way to expand the scale of PHB production, and promotes PHB industrial production process using Methane-Utilizing mixed Culture.