Lactobacillus plantarum 299v surface-bound GAPDH: a new insight into enzyme cell walls location

The aim of this study was to provide new insight into the mechanism whereby the housekeeping enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) locates to cell walls of Lactobacillus plantarum 299v. After purification, cytosolic and cell wall GAPDH (cw-GAPDH) forms were characterized and shown to be identical homotetrameric active enzymes. GAPDH concentration on cell walls was growth-time dependent. Free GAPDH was not observed on the culture supernatant at any time during growth, and provoked cell lysis was not concomitant with any reassociation of GAPDH onto the cell surface. Hence, with the possibility of cw-GAPDH resulting from autolysis being unlikely, entrapment of intracellular GAPDH on the cell wall after a passive efflux through altered plasma membrane was investigated. Flow cytometry was used to assess L. plantarum 299v membrane permeabilization after labeling with propidium iodide (PI). By combining PI uptake and cw-GAPDH activity measurements, we demonstrate here that the increase in cw-GAPDH concentration from the early exponential phase to the late stationary phase is closely related to an increase in plasma membrane permeability during growth. Moreover, we observed that increases in both plasma membrane permeability and cw-GAPDH activity were delayed when glucose was added during L. plantarum 299v growth. Using a double labeling of L. plantarum 299v cells with anti-GAPDH antibodies and propidium iodide, we established unambiguously that cells with impaired membrane manifest five times more cw-GAPDH than unaltered cells. Our results show that plasma membrane permeability appears to be closely related to the efflux of GAPDH on the bacterial cell surface, offering new insight into the understanding of the cell wall location of this enzyme.

Temporal gene expression and probiotic attributes of Lactobacillus acidophilus during growth in milk

Lactic acid bacteria have been used as starter strains in the production of fermented dairy products for centuries. Lactobacillus acidophilus is a widely recognized probiotic bacteria commonly added to yogurt and used in dietary supplements. In this study, a whole genome microarray was employed to monitor gene expression of L. acidophilus NCFM cells propagated in 11% skim milk during early, mid and late logarithmic phase, and stationary phase. Approximately 21% of 1,864 open reading frames were differentially expressed at least in one time point. Genes differentially expressed in skim milk included several members of the proteolytic enzyme system. Expression of prtP (proteinase precursor) and prtM (maturase) increased over time as well as several peptidases and transport systems. Expression of Opp1 (oligopeptide transport system 1) was highest at 4 h, whereas gene expression of Opp2 increased over time reaching its highest level at 12 h, suggesting that the 2 systems have different specificities. Expression of a 2-component regulatory system, previously shown to regulate acid tolerance and proteolytic activity, also increased during the early log and early stationary phases of growth. Expression of the genes involved in lactose utilization increased immediately (5 min) upon exposure to milk. The acidification activity, survival under storage conditions, and adhesion to mucin and Caco-2 tissue culture cells of selected mutants containing insertionally inactivated genes differentially expressed in the wild-type strain during growth in milk were examined for any potential links between probiotic properties and bacterial growth and survival in milk. Some of the most interesting genes found to be expressed in milk were correlated with signaling (autoinducer-2) and adherence to mucin and intestinal epithelial cells, in vitro.

Strain- and matrix-dependent adhesion of Lactobacillus plantarum is mediated by proteinaceous bacterial compounds

AIMS

The ability of 31 Lactobacillus plantarum strains to adhere to biological matrixes was evaluated, and the molecules involved in adherence were studied.

METHODS AND RESULTS

Mucin, basement membrane proteins and Caco-2 cells were used in adhesion tests. These in vitro assays, together with a yeast agglutination test, were found to be discriminative for screening Lact. plantarum strains for adhesion. Some strains, such as 299v, CBE, BMCM12, Col4S and T25, were shown to possess interesting adhesion properties in at least two models. The adhesion of these strains was strongly inhibited when the bacterial cells were pretreated with trypsin. Lithium chloride and methyl-alpha-D-mannoside also inhibited adhesion to a lower extent.

CONCLUSIONS

The adhesion of Lact. plantarum depends on both the model and the strain used. The chemical and enzymatic pretreatments applied to the bacterial cells suggested that lectin-like adhesins and other proteinaceous cell-surface structures are involved in adhesion of these strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

We found a great diversity in the adhesion properties between Lact. plantarum strains. Based upon the adhesive property of these strains interesting candidates were identified, that will undergo further study as potential probiotics.

Support surfaces--a technology review

Technology assessment performed on the wide range of clinical support systems available highlights the potential difficulties encountered when already utilized clinical therapies become subject to careful scientific scrutiny. The technology assessment committee must look beyond tacitly accepted indications for technology use and instead focus their evaluations on current, published clinical outcomes research. Where this latter clinical research is lacking, the technology assessment committee's goal is to balance the best available evidence of clinical safety and efficacy of a technology against the relative costs of that therapy.

Technology assessment: analytical product research

In this series on health technology assessment, not only will technology design, scientifically validated therapeutic efficacy and relative cost efficiency be evaluated, but also the medical ethical challenges of technology introduction will be explored. Ideally, these considerations can form the foundation for a technology assessment team's discussions.

Devising and delivering objectives for disease state management

Comprehensive, objective plans of clinical care that reflect the optimal diagnosis and treatment must be developed. Standardized plans of patient care that are centered around a specific disease entity meet outcomes management and maximize health delivery quality. This integration is embodied in the philosophy of disease state management.

Cost-effective wound care: new priorities driven by outcomes

International demands for optimizing the quality and cost effectiveness of health care requires the rethinking of traditional wound care paradigms. This essay defines cost effectiveness as the comparative measure of costs to achieve a given clinical outcome. Among some of the issues that need to be addressed are having more studies that compare the cost effectiveness of wound care modalities, defining what an acceptable outcome for a prescribed treatment program is, deciding who should define the significant outcome, and measuring the values of each therapy.

Critical paths for wound care

Critical paths and clinical algorithms are an adjunct for quality management of an average person's health problems. A critical path attempts to achieve continuous quality improvement by aligning actions of the care team. Critical paths are difficult to construct for chronically ill patients with comorbidities. Therefore, clinicians are challenged to consider key elements of critical paths: describing normalcy, identifying variances, creating differential diagnoses, handling individual responses to care, managing continuity of care, communicating among team members, discerning chronic disease dilemmas, and developing a common pathway model. Continuity of care and cost effectiveness can be the result of close attention to aspects of critical pathways. Medicine is frequently described as art blended with science. Nowhere is the art of medicine more apparent than in the management of wounds. The challenge of wound care has taxed the ingenuity of countless caregivers from the days when therapeutic armaments consisted of only salves, balms, and poultices to the present plethora of high-tech therapies. Unfortunately, the treatment of patients with wounds for the most part has been relegated to a little-appreciated segment of an equally unappreciated and "unattractive" category of chronic disease.