Comparison of image analysis software packages in the assessment of adhesion of microorganisms to mucosal epithelium using confocal laser scanning microscopy

Probiotic Potential of Bacillus amyloliquefaciens Isolated from Tibetan Yaks

The Tibetan livestock sector is now ailing from many infectious ailments brought on by harmful microorganisms. Therefore, this research aimed to assess the probiotic potential and safety of Bacillus amyloliquefaciens isolated from yaks in the Tibet area to provide upper-edge strain resources for probiotics development. The four strains isolated from the intestine of yaks had been identified as Bacillus amyloliquefaciens after the 16S rRNA sequence. The ethanol, bile salt, and acid tolerance revealed that the isolates had significant tolerance levels. The antibiotics susceptibility assay showed that the strains were sensitive to commonly used antibiotics, while the antibacterial assay prevented the isolates from outperforming five harmful bacteria in terms of antibacterial potency. Moreover, it was evident that strain BA5 had the strongest activity to scavenge hydroxyl radical and reduce power. According to the animal experiment, no apparent pathological change was observed in intestinal tissue sections. Furthermore, the strain had a positive effect on promoting the development of jejunal villi referred to its safety. Therefore, more research is required into the bacteriostatic and antioxidant capabilities of isolates in animal production.

Epidermis as a Platform for Bacterial Transmission

The epidermis constitutes a continuous external layer covering the body, offering protection against bacteria, the most abundant living organisms that come into contact with this barrier. The epidermis is heavily colonized by commensal bacterial organisms that help protect against pathogenic bacteria. The highly regulated and dynamic interaction between the epidermis and commensals involves the host’s production of nutritional factors promoting bacterial growth together to chemical and immunological bacterial inhibitors. Signal trafficking ensures the system’s homeostasis; conditions that favor colonization by pathogens frequently foster commensal growth, thereby increasing the bacterial population size and inducing the skin’s antibacterial response, eliminating the pathogens and re-establishing the normal density of commensals. The microecological conditions of the epidermis favors Gram-positive organisms and are unsuitable for long-term Gram-negative colonization. However, the epidermis acts as the most important host-to-host transmission platform for bacteria, including those that colonize human mucous membranes. Bacteria are frequently shared by relatives, partners, and coworkers. The epidermal bacterial transmission platform of healthcare workers and visitors can contaminate hospitalized patients, eventually contributing to cross-infections. Epidermal transmission occurs mostly via the hands and particularly through fingers. The three-dimensional physical structure of the epidermis, particularly the fingertips, which have frictional ridges, multiplies the possibilities for bacterial adhesion and release. Research into the biology of bacterial transmission via the hands is still in its infancy; however, tribology, the science of interacting surfaces in relative motion, including friction, wear and lubrication, will certainly be an important part of it. Experiments on finger-to-finger transmission of microorganisms have shown significant interindividual differences in the ability to transmit microorganisms, presumably due to genetics, age, sex, and the gland density, which determines the physical, chemical, adhesive, nutritional, and immunological status of the epidermal surface. These studies are needed to optimize interventions and strategies for preventing the hand transmission of microorganisms.

Probiotic Properties of Bacillus proteolyticus Isolated From Tibetan Yaks, China

Yaks (Bos grunniens) live primarily in high-altitude hypoxic conditions and have a unique intestinal micro-ecosystem, remarkable adaptability, and strong climatic resistance. Accumulating evidence revealed the importance of probiotics in host metabolism, gut microbiota, growth performance, and health. The goal of this study was to screen out probiotics with excellent probiotic potential for clinical application. In this study, four strains of Bacillus, i.e., Bacillus proteolyticus (named Z1 and Z2), Bacillus amyloliquefaciens (named J), and Bacillus subtilis (named K), were isolated and identified. Afterward, their probiotic potential was evaluated. Antioxidant activity tests revealed that Z1 had the highest DPPH and hydroxyl radical scavenging activity, whereas Z2 had higher reducing power and inhibited lipid peroxidation. Additionally, the antibacterial testing revealed that all strains were antagonistic to three indicator pathogens, Escherichia coli C83902, Staphylococcus aureus BNCC186335, and Salmonella enteritidis NTNC13349. These isolates also had a higher hydrophobicity, autoaggregation, and acid and bile tolerance, all of which helped to survive and keep dangerous bacteria out of the host intestine. Importantly, all strains could be considered safe in terms of antibiotic susceptibility and lack of hemolysis. In conclusion, this is the first study to show that B. proteolyticus and B. amyloliquefaciens isolated from yaks have probiotic potential, providing a better foundation for future clinical use.

Fibronectin (FN) cooperated with TLR2/TLR4 receptor to promote innate immune responses of macrophages via binding to integrin β1

Macrophages could adhere to extracellular matrix molecules(ECM) to induce the expression of pro-inflammatory mediators and phagocytosis that contribute to the pathogenesis of pulmonary infection diseases. Fibronectin (FN) is a large glycoprotein capable of interacting with various ECM molecules produced by a variety of cell types and involved in cell attachment and chemotaxis. However, it is unknown whether FN regulates the expression of pro-inflammatory mediators and phagocytosis of macrophages in the injured lung tissue. Here, we investigated the interaction between FN and integrin β1 in macrophages, which promotes toll-like receptor 2/4 (TLR2/TLR4) signaling pathways to enhance expression of pro-inflammatory mediators and phagocytosis by macrophages. Our results show that lipopolysaccharide (LPS), lipoteichoic acid (LTA) and peptidoglycan (PGN) significantly increase FN expression of macrophages; FN substantially enhances interleukin 6 (IL-6), tumor necrosis factor-α (TNFα), ras-related C3 botulinum toxin substrate 1/2 (Rac1/2), and cell division control protein 42 homolog (Cdc42) expression and phagocytosis of macrophages. However, FN could not enhance pro-inflammatory cytokines and phagocytosis of macrophages induced by LPS and PGN in integrin β1-/- macrophages. Furthermore, applied integrin β1 blocking peptide abrogated the effects that FN promotes innate immune responses of macrophages to LPS and PGN. Those data indicated that the enhanced pro-inflammatory mediators and phagocytosis of macrophages by FN-integrin β1 signal was through co-operating with TLR2/TLR4 signaling. This study suggests that FN play an essential role in the pathogenesis of pulmonary infection disease.

Effects of Nano-hydroxyapatite/Poly(DL-lactic-co-glycolic acid) Microsphere-Based Composite Scaffolds on Repair of Bone Defects: Evaluating the Role of Nano-hydroxyapatite Content

The aim of the current study was to prepare microsphere-based composite scaffolds made of nano-hydroxyapatite (nHA)/poly (DL-lactic-co-glycolic acid) (PLGA) at different ratios and evaluate the effects of nHA on the characteristics of scaffolds for tissue engineering application. First, microsphere-based composite scaffolds made of two ratios of nHA/PLGA (nHA/PLGA = 20/80 and nHA/PLGA = 50/50) were prepared. Then, the effects of nHA on the wettability, mechanical strength, and degradation of scaffolds were investigated. Second, the biocompatibility and osteoinductivity were evaluated and compared by co-culture of scaffolds with bone marrow stromal stem cells (BMSCs). The results showed that the adhesion, proliferation, and osteogenic differentiation of BMSCs with nHA/PLGA (50/50) were better than those with nHA/PLGA (20/80). Finally, we implanted the scaffolds into femur bone defects in a rabbit model, then the capacity of guiding bone regeneration as well as the in vivo degradation were observed by micro-CT and histological examinations. After 4 weeks' implantation, there was no significant difference on the repair of bone defects. However, after 8 and 12 weeks' implantation, the nHA/PLGA (20/80) exhibited better bone formation than nHA/PLGA (50/50). These results suggested that a proper concentration of nHA in the nHA/PLGA composite should be taken into account when the composite scaffolds were prepared, which plays an important role in the biocompatibility, degradation rate and osteoconductivity.

Genome shuffling of Lactobacillus plantarum C88 improves adhesion

Genome shuffling is an important method for rapid improvement in microbial strains for desired phenotypes. In this study, ultraviolet irradiation and nitrosoguanidine were used as mutagens to enhance the adhesion of the wild-type Lactobacillus plantarum C88. Four strains with better property were screened after mutagenesis to develop a library of parent strains for three rounds of genome shuffling. Fusants F3-1, F3-2, F3-3, and F3-4 were screened as the improved strains. The in vivo and in vitro tests results indicated that the population after three rounds of genome shuffling exhibited improved adhesive property. Random Amplified Polymorphic DNA results showed significant differences between the parent strain and recombinant strains at DNA level. These results suggest that the adhesive property of L. plantarum C88 can be significantly improved by genome shuffling. Improvement in the adhesive property of bacterial cells by genome shuffling enhances the colonization of probiotic strains which further benefits to exist probiotic function.

Different binarization processes validated against manual counts of fluorescent bacterial cells

State of the art software methods (such as fixed value approaches or statistical approaches) to create a binary image of fluorescent bacterial cells are not as accurate and precise as they should be for counting bacteria and measuring their area. To overcome these bottlenecks, we introduce biological significance to obtain a binary image from a greyscale microscopic image. Using our biological significance approach we are able to automatically count about the same number of cells as an individual researcher would do by manual/visual counting. Using the fixed value or statistical approach to obtain a binary image leads to about 20% less cells in automatic counting. In our procedure we included the area measurements of the bacterial cells to determine the right parameters for background subtraction and threshold values. In an iterative process the threshold and background subtraction values were incremented until the number of particles smaller than a typical bacterial cell is less than the number of bacterial cells with a certain area. This research also shows that every image has a specific threshold with respect to the optical system, magnification and staining procedure as well as the exposure time. The biological significance approach shows that automatic counting can be performed with the same accuracy, precision and reproducibility as manual counting. The same approach can be used to count bacterial cells using different optical systems (Leica, Olympus and Navitar), magnification factors (200× and 400×), staining procedures (DNA (Propidium Iodide) and RNA (FISH)) and substrates (polycarbonate filter or glass).

Intervention effects of ganoderma lucidum spores on epileptiform discharge hippocampal neurons and expression of neurotrophin-4 and N-cadherin

Epilepsy can cause cerebral transient dysfunctions. Ganoderma lucidum spores (GLS), a traditional Chinese medicinal herb, has shown some antiepileptic effects in our previous studies. This was the first study of the effects of GLS on cultured primary hippocampal neurons, treated with Mg²⁺ free medium. This in vitro model of epileptiform discharge hippocampal neurons allowed us to investigate the anti-epileptic effects and mechanism of GLS activity. Primary hippocampal neurons from <1 day old rats were cultured and their morphologies observed under fluorescence microscope. Neurons were confirmed by immunofluorescent staining of neuron specific enolase (NSE). Sterile method for GLS generation was investigated and serial dilutions of GLS were used to test the maximum non-toxic concentration of GLS on hippocampal neurons. The optimized concentration of GLS of 0.122 mg/ml was identified and used for subsequent analysis. Using the in vitro model, hippocampal neurons were divided into 4 groups for subsequent treatment i) control, ii) model (incubated with Mg²⁺ free medium for 3 hours), iii) GLS group I (incubated with Mg²⁺ free medium containing GLS for 3 hours and replaced with normal medium and incubated for 6 hours) and iv) GLS group II (neurons incubated with Mg²⁺ free medium for 3 hours then replaced with a normal medium containing GLS for 6 hours). Neurotrophin-4 and N-Cadherin protein expression were detected using Western blot. The results showed that the number of normal hippocampal neurons increased and the morphologies of hippocampal neurons were well preserved after GLS treatment. Furthermore, the expression of neurotrophin-4 was significantly increased while the expression of N-Cadherin was decreased in the GLS treated group compared with the model group. This data indicates that GLS may protect hippocampal neurons by promoting neurotrophin-4 expression and inhibiting N-Cadherin expression.

Effect of microbial treatment on the prevention and removal of paraffin deposits on stainless steel surfaces

In this study, biosurfactant-producing strain N2 and non-biosurfactant producing stain KB18 were used to investigate the effects of microbial treatment on the prevention and removal of paraffin deposits on stainless steel surfaces. Strain N2, with a biosurfactant production capacity, reduced the contact angle of stainless steel to 40.04°, and the corresponding adhesion work of aqueous phase was decreased by 26.5 mJ/m(2). By contrast, KB18 could only reduce the contact angle to 50.83°, with a corresponding 7.6 mJ/m(2) decrease in the aqueous phase work adhesion. The paraffin removal test showed that the paraffin removal efficiencies of strain N2 and KB18 were 79.0% and 61.2%, respectively. Interestingly, the N2 cells could attach on the surface of the oil droplets to inhibit droplets coalescence. These results indicate that biosurfactant-producing strains can alter the wettability of stainless steel and thus eliminate paraffin deposition.

Do mucosal folds in the eustachian tube function as microturbinates?

OBJECTIVES/HYPOTHESIS

Mucosal folds in the eustachian tube (ET) may function as microturbinates and provide protection and clearance.

STUDY DESIGN

Descriptive study.

METHODS

Nineteen whole-mount temporal bone ET specimens (nine pediatric and 10 adult) were evaluated in the present study. Five specific localizations for each case were selected. The cartilaginous segment of the ET was divided vertically and the length of mucosal surfaces and the number of mucosal folds of anterior and posterior walls on the histological sections were analyzed with MetaMorph 7.5.2.0 software.

RESULTS

The length of the mucosal surface of the posterior wall of the ET was longer than the anterior wall (P < .05). In pediatric specimens, the posterior wall had more mucosal folds than adult specimens (P < .05).

CONCLUSIONS

Microturbinates in the posterior wall of the ET may provide important protection and clearance functions for children and play a role in the pathogenesis of eustachian tube dysfunction

Quantification of cell size distribution as applied to the growth of Corynebacterium glutamicum

It is known that the cell size is related to the physiological state of a cell. Therefore, cell size distribution directly reflects the average physiological properties of the cell culture. Cell size distribution can be enumerated by image analysis, flow cytometry and coulter counter. In this study, image analysis was used to characterize the cell size distribution during the growth of Corynebacterium glutamicum and was further analyzed by a distribution function. The parameters of the distribution function indicate the mean value and spread of the distribution. Analysis demonstrated that the maximum specific growth rate was higher (0.67h(-1)) for the growth obtained through serial dilution of seed as compared to growth from a normal seed culture (0.53h(-1)). This was due to a greater percentage of the cell population being in the state of division for the growth through serial dilution in the mid-log phase. The measurement of the cell size distribution demonstrated that the average cell size decreased during the course of growth. The distribution function was also used to enumerate the average specific growth rate of both the conditions of the culture. The demonstrated methodology can be used to predict an average growth property of a cell culture.

Integrin beta 1 regulates phagosome maturation in macrophages through Rac expression

Phagocytosis and subsequent phagosome maturation by professional phagocytes are essential in the clearance of infectious microbial pathogens. The molecular regulation of phagosome maturation is largely unknown. We show that integrin beta(1) plays critical roles in the phagocytosis of microbial pathogens and phagosome maturation. Macrophages lacking integrin beta(1) expression exhibit reduced phagocytosis of bacteria, including group B streptococcus and Staphylococcus aureus. Furthermore, phagosomes from macrophages lacking integrin beta(1) show lowered maturation rate, defective acquisition of lysosome membrane markers, and reduced F-actin accumulation in the periphagosomal region. Integrin beta(1)-deficient macrophages exhibit impaired bactericidal activity. We found that the expression of the Rho family GTPases Rac1, Rac2, and Cdc42 was reduced in integrin beta(1)-deficient macrophages. Ectopic expression of Rac1, but not Cdc42, in integrin beta(1)-deficient macrophages restored defective phagosome maturation and F-actin accumulation in the periphagosomal region. Importantly, macrophages lacking Rac1/2 also exhibit defective maturation of phagosomes derived from opsonized Escherichia coli or IgG beads. Taken together, these results suggest that integrin beta(1) regulates phagosome maturation in macrophages through Rac expression.

MYC can induce DNA breaks in vivo and in vitro independent of reactive oxygen species

MYC overexpression is thought to initiate tumorigenesis by inducing cellular proliferation and growth and to be restrained from causing tumorigenesis by inducing cell cycle arrest, cellular senescence, and/or apoptosis. Here we show that MYC can induce DNA breaks both in vitro and in vivo independent of increased production of reactive oxygen species (ROS). We provide an insight into the specific circumstances under which MYC generates ROS in vitro and propose a possible mechanism. We found that MYC induces DNA double-strand breaks (DSBs) independent of ROS production in murine lymphocytes in vivo as well as in normal human foreskin fibroblasts (NHFs) in vitro in normal (10%) serum, as measured by gammaH2AX staining. However, NHFs cultured in vitro in low serum (0.05%) and/or ambient oxygen saturation resulted in ROS-associated oxidative damage and DNA single-strand breaks (SSBs), as measured by Ape-1 staining. In NHFs cultured in low versus normal serum, MYC induced increased expression of CYP2C9, a gene product well known to be associated with ROS production. Specific inhibition of CYP2C9 by small interfering RNA was shown to partially inhibit MYC-induced ROS production. Hence, MYC overexpression can induce ROS and SSBs under some conditions, but generally induces widespread DSBs in vivo and in vitro independent of ROS production.

Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori

AIM

To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H. pylori).

METHODS

Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H. pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H. pylori to stomach sections.

RESULTS

Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H. pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H. pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric, borage and parsley were able to inhibit the adhesion of H. pylori strains to the stomach sections.

CONCLUSION

Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H. pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H. pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.