Cinnamaldehyde induces changes in the protein profile of Salmonella Typhimurium biofilm

Current strategies for monitoring and controlling bacterial biofilm formation on medical surfaces

Biofilms, intricate microbial communities that attach to surfaces, especially medical devices, form an exopolysaccharide matrix, which enables bacteria to resist environmental pressures and conventional antimicrobial agents, leading to the emergence of multi-drug resistance. Biofilm-related infections associated with medical devices are a significant public health threat, compromising device performance. Therefore, developing effective methods for supervising and managing biofilm growth is imperative. This in-depth review presents a systematic overview of strategies for monitoring and controlling bacterial biofilms. We first outline the biofilm creation process and its regulatory mechanisms. The discussion then progresses to advancements in biosensors for biofilm detection and diverse treatment strategies. Lastly, this review examines the obstacles and new perspectives associated with this domain to facilitate the advancement of innovative monitoring and control solutions. These advancements are vital in combating the spread of multi drug-resistant bacteria and mitigating public health risks associated with infections from biofilm formation on medical instruments.

Application of essential oils as slow-release antimicrobial agents in food preservation: Preparation strategies, release mechanisms and application cases

Food spoilage caused by foodborne microorganisms will not only cause significant economic losses, but also the toxins produced by some microorganisms will also pose a serious threat to human health. Essential oil (EOs) has significant antimicrobial activity, but its application in the field of food preservation is limited because of its volatile, insoluble in water and sensitive to light and heat. Therefore, in order to solve these problems effectively, this paper first analyzed the antibacterial effect of EOs as an antimicrobial agent on foodborne bacteria and its mechanism. Then, the application strategies of EOs as a sustained-release antimicrobial agent in food preservation were reviewed. On this basis, the release mechanism and application cases of EOs in different antibacterial composites were analyzed. The purpose of this paper is to provide technical support and solutions for the preparation of new antibacterial packaging materials based on plant active components to ensure food safety and reduce food waste.

Cinnamaldehyde/lactulose combination therapy alleviates thioacetamide-induced hepatic encephalopathy via targeting P2X7R-mediated NLRP3 inflammasome signaling

AIMS

Cinnamaldehyde (CA), the main active constituent of cinnamon oil, is reported to have neuroprotective effects. However, the potential benefits of CA for brain protection in hepatic encephalopathy (HE) are still not understood. Thus, the present study investigates the possible ameliorative effect of CA (70 mg/kg/day, I.P.) either alone or in combination with lactulose (Lac) (5.3 g/kg/day, oral) against thioacetamide (TAA)-induced hepatic encephalopathy in rats.

MATERIALS AND METHODS

For induction of HE, TAA (200 mg/kg) was intraperitoneally administered for 1 week at alternative days. CA, Lac and Lac+CA were administered for 14 days prior to and for further 7 days together with TAA injection.

KEY FINDINGS

CA, Lac and Lac+CA combination effectively attenuated TAA-induced HE; as indicated by the improvement in behavioral tests, mitigation of pathological abnormalities in both liver and brain, the significant reduction in serum hyperammonemia and amelioration in liver function biomarkers; ALT and AST. This was accompanied with a substantial restoration of redox state in liver and brain; MDA and GSH levels. Moreover, CA, Lac and Lac+CA combination reduced neuroinflammation as demonstrated by the notable attenuation of P2X7R, NLRP3, caspase-1, IL-1β, GFAP and Iba1 brain levels, as well as the amelioration of brain edema as manifested by reduction in AQP4 levels in brain.

SIGNIFICANCE

Our study has demonstrated that CA in combination with Lac possesses a superior neuroprotective effect over Lac alone against TAA-induced HE by attenuation of P2X7R/NLRP3 mediated neuroinflammation and relieving brain edema.

Recent advances and role of melatonin in post-harvest quality preservation of shiitake (Lentinula edodes)

Shiitake mushrooms are renowned for their popularity and robust nutritional value, are susceptible to spoilage due to their inherent biodegradability. Nevertheless, because of their lack of protection, these mushrooms have a short shelf life. Throughout the post-harvest phase, mushrooms experience a persistent decline in quality. This is evidenced by changes such as discoloration, reduced moisture content, texture changes, an increase in microbial count, and the depletion of nutrients and flavor. Ensuring postharvest quality preservation and prolonging mushroom shelf life necessitates the utilization of post-harvest preservation techniques, including physical, chemical, and thermal processes. This review provides a comprehensive overview of the deterioration processes affecting mushroom quality, covering elements such as moisture loss, discoloration, texture alterations, increased microbial count, and the depletion of nutrients and flavor. It also explores the key factors influencing these processes, such as temperature, relative humidity, water activity, and respiration rate. Furthermore, the review delves into recent progress in preserving mushrooms through techniques such as drying, cooling, packaging, irradiation, washing, and coating.

Antimicrobial and mechanical assessment of cellulose-based thermoformable material for invisible dental braces with natural essential oils protecting from biofilm formation

Controlling biofilm formation in the oral cavity during orthodontic treatments is crucial. Therefore, antimicrobial surfaces for invisible dental appliances are of interest to both therapists and patients. Here we present a cellulose-based thermoformable material used for invisible braces that can be loaded with essential oils (EOs) having antibacterial and antifungal properties. We hypothesize that this material can absorb and release EOs, thus providing an antimicrobial effect without compromising the safety and mechanical properties necessary for dental invisible braces. Conventional microbiology and isothermal microcalorimetry analyses revealed that the thermoformable material loaded with essential oils significantly delayed the biofilm formation of oral streptococci (S. mutans and S. mitis) under static conditions (p < 0.05) and while simulating saliva flow (p < 0.05). In addition, cytotoxicity tests (ISO 10993-5), revealed that the loaded material is well tolerated by human gingival fibroblasts. Finally, the loading with antibacterial agents did not significantly alter the mechanical properties and stability of the material (initial force (p = 0.916); initial stress (p = 0.465)). Compared to gold-standard clear aligner materials, this material offers a reliable transmission of forces for orthodontic treatments. Moreover, this approach exhibits the potential for acting as an oral drug delivery platform for multiple compounds.

Application of Phytogenic Liquid Supplementation in Soil Microbiome Restoration in Queensland Pasture Dieback

Pasture production is vital in cattle farming as it provides animals with food and nutrients. Australia, as a significant global beef producer, has been experiencing pasture dieback, a syndrome of deteriorating grassland that results in the loss of grass and the expansion of weeds. Despite two decades of research and many remediation attempts, there has yet to be a breakthrough in understanding the causes or mechanisms involved. Suggested causes of this phenomenon include soil and plant microbial pathogens, insect infestation, extreme heat stress, radiation, and others. Plants produce a range of phytomolecules with antifungal, antibacterial, antiviral, growth-promoting, and immunostimulant effects to protect themselves from a range of environmental stresses. These products are currently used more in human and veterinary health than in agronomy. In this study, we applied a phytogenic product containing citric acid, carvacrol, and cinnamaldehyde, to investigate its ability to alleviate pasture dieback. The phytogenic liquid-based solution was sprayed twice, one week apart, at 5.4 L per hectare. The soil microbial community was investigated longitudinally to determine long-term effects, and pasture productivity and plant morphometric improvements were explored. The phytogenic liquid significantly improved post-drought recovery of alpha diversity and altered temporal and spatial change in the community. The phytogenic liquid reduced biomarker genera associated with poor and polluted soils and significantly promoted plant and soil beneficial bacteria associated with plant rhizosphere and a range of soil benefits. Phytogenic liquid application produced plant morphology improvements and a consistent enhancement of pasture productivity extending beyond 18 months post-application. Our data show that phytogenic products used in the livestock market as an alternative to antibiotics may also have a beneficial role in agriculture, especially in the light of climate change-related soil maintenance and remediation.

Advances in the Role and Mechanisms of Essential Oils and Plant Extracts as Natural Preservatives to Extend the Postharvest Shelf Life of Edible Mushrooms

China has a large variety of edible mushrooms and ranks first in the world in terms of production and variety. Nevertheless, due to their high moisture content and rapid respiration rate, they experience constant quality deterioration, browning of color, loss of moisture, changes in texture, increases in microbial populations, and loss of nutrition and flavor during postharvest storage. Therefore, this paper reviews the effects of essential oils and plant extracts on the preservation of edible mushrooms and summarizes their mechanisms of action to better understand their effects during the storage of mushrooms. The quality degradation process of edible mushrooms is complex and influenced by internal and external factors. Essential oils and plant extracts are considered environmentally friendly preservation methods for better postharvest quality. This review aims to provide a reference for the development of new green and safe preservation and provides research directions for the postharvest processing and product development of edible mushrooms.

Exploring Possible Ways to Enhance the Potential and Use of Natural Products through Nanotechnology in the Battle against Biofilms of Foodborne Bacterial Pathogens

Biofilms enable pathogenic bacteria to survive in unfavorable environments. As biofilm-forming pathogens can cause rapid food spoilage and recurrent infections in humans, especially their presence in the food industry is problematic. Using chemical disinfectants in the food industry to prevent biofilm formation raises serious health concerns. Further, the ability of biofilm-forming bacterial pathogens to tolerate disinfection procedures questions the traditional treatment methods. Thus, there is a dire need for alternative treatment options targeting bacterial pathogens, especially biofilms. As clean-label products without carcinogenic and hazardous potential, natural compounds with growth and biofilm-inhibiting and biofilm-eradicating potentials have gained popularity as natural preservatives in the food industry. However, the use of these natural preservatives in the food industry is restricted by their poor availability, stability during food processing and storage. Also there is a lack of standardization, and unattractive organoleptic qualities. Nanotechnology is one way to get around these limitations and as well as the use of underutilized bioactives. The use of nanotechnology has several advantages including traversing the biofilm matrix, targeted drug delivery, controlled release, and enhanced bioavailability, bioactivity, and stability. The nanoparticles used in fabricating or encapsulating natural products are considered as an appealing antibiofilm strategy since the nanoparticles enhance the activity of the natural products against biofilms of foodborne bacterial pathogens. Hence, this literature review is intended to provide a comprehensive analysis of the current methods in nanotechnology used for natural products delivery (biofabrication, encapsulation, and nanoemulsion) and also discuss the different promising strategies employed in the recent and past to enhance the inhibition and eradication of foodborne bacterial biofilms.

Raspberry Ketone-Mediated Inhibition of Biofilm Formation in Salmonella enterica Typhimurium-An Assessment of the Mechanisms of Action

Salmonella enterica is an important foodborne pathogen that causes gastroenteritis and systemic infection in humans and livestock. Salmonella biofilms consist of two major components-amyloid curli and cellulose-which contribute to the prolonged persistence of Salmonella inside the host. Effective agents for inhibiting the formation of biofilms are urgently needed. We investigated the antibiofilm effect of Raspberry Ketone (RK) and its mechanism of action against Salmonella Typhimurium 14028 using the Congo red agar method, Calcofluor staining, crystal violet method, pellicle assay, and the TMT-labeled quantitative proteomic approach. RK suppressed the formation of different types of Salmonella biofilms, including pellicle formation, even at low concentrations (200 µg/mL). Furthermore, at higher concentrations (2 mg/mL), RK exhibited bacteriostatic effects. RK repressed cellulose deposition in Salmonella biofilm through an unknown mechanism. Swimming and swarming motility analyses demonstrated reduced motility in RK-treated S. typhimurium. Proteomics analysis revealed that pathways involved in amyloid curli production, bacterial invasion, flagellar motility, arginine biosynthesis, and carbohydrate metabolism, were targeted by RK to facilitate biofilm inhibition. Consistent with the proteomics data, the expressions of csgB and csgD genes were strongly down-regulated in RK-treated S. typhimurium. These findings clearly demonstrated the Salmonella biofilm inhibition capability of RK, justifying its further study for its efficacy assessment in clinical and industrial settings.

Cinnamomum: The New Therapeutic Agents for Inhibition of Bacterial and Fungal Biofilm-Associated Infection

Due to the potent antibacterial properties of Cinnamomum and its derivatives, particularly cinnamaldehyde, recent studies have used these compounds to inhibit the growth of the most prevalent bacterial and fungal biofilms. By inhibiting flagella protein synthesis and swarming motility, Cinnamomum could suppress bacterial attachment, colonization, and biofilm formation in an early stage. Furthermore, by downregulation of Cyclic di‐guanosine monophosphate (c‐di‐GMP), biofilm-related genes, and quorum sensing, this compound suppresses intercellular adherence and accumulation of bacterial cells in biofilm and inhibits important bacterial virulence factors. In addition, Cinnamomum could lead to preformed biofilm elimination by enhancing membrane permeability and the disruption of membrane integrity. Moreover, this substance suppresses the Candida species adherence to the oral epithelial cells, leading to the cell wall deformities, damage, and leakages of intracellular material that may contribute to the established Candida’s biofilm elimination. Therefore, by inhibiting biofilm maturation and destroying the external structure of biofilm, Cinnamomum could boost antibiotic treatment success in combination therapy. However, Cinnamomum has several disadvantages, such as poor solubility in aqueous solution, instability, and volatility; thus, the use of different drug-delivery systems may resolve these limitations and should be further considered in future investigations. Overall, Cinnamomum could be a promising agent for inhibiting microbial biofilm-associated infection and could be used as a catheter and other medical materials surface coatings to suppress biofilm formation. Nonetheless, further in vitro toxicology analysis and animal experiments are required to confirm the reported molecular antibiofilm effect of Cinnamomum and its derivative components against microbial biofilm.

Characterization of Clinical Salmonella entericas Trains in Huzhou, China

Background

Salmonella enterica subspecies enterica causes salmonellosis in humans and animals and is an important antecedent of food infections worldwide. This study collected 105 clinical S. enterica isolates from diarrhoea samples from six sentinel hospitals for active surveillance of foodborne diseases in Huzhou, China, between 2018 and 2020. These represented all the Salmonella isolates collected in Huzhou during that period.

Methods

The isolates were characterized by serovar determination, antimicrobial susceptibility tests, and pulse-field gel electrophoresis (PFGE) typing.

Results

The 105 Salmonella strains were mainly S. typhimurium (35.24%, 95% CI from 25.95 to 44.53%) and S. enteritidis (18.10%, 95% CI from 10.61 to 25.58%). Testing indicated that the resistance rate of the Salmonella strains ranged from 0.00% to 70.48%, and the highest resistance rate was for ampicillin (70.48%; 74/105), followed by tetracycline (67.62%; 71/105) and doxycycline (65.71%; 69/105). Following XbaI digestion, the 105 strains yielded 93 PFGE patterns, and 15 clones had similarity values >85.00%.

Conclusions

Our analyses revealed the serovar distribution of isolates recovered from diarrhoea patients and the characteristics of resistant strains in Huzhou from 2018 to 2020. Our results highlight a serovar shift and a concerning number of multidrug-resistant (MDR) strains. Continued surveillance of Salmonella and their MDR profiles and efforts to control the rapid increase in antimicrobial resistance among Salmonella in Huzhou are needed.

Appraisal of Cinnamaldehyde Analogs as Dual-Acting Antibiofilm and Anthelmintic Agents

Cinnamaldehyde has a broad range of biological activities, which include antibiofilm and anthelmintic activities. The ever-growing problem of drug resistance and limited treatment options have created an urgent demand for natural molecules with antibiofilm and anthelmintic properties. Hence, we hypothesized that molecules with a scaffold structurally similar to that of cinnamaldehyde might act as dual inhibitors against fungal biofilms and helminths. In this regard, eleven cinnamaldehyde analogs were tested to determine their effects on fungal Candida albicans biofilm and nematode Caenorhabditis elegans. α-Methyl and trans-4-methyl cinnamaldehydes efficiently inhibited C. albicans biofilm formation (>90% inhibition at 50 μg/mL) with minimum inhibitory concentrations (MICs) of ≥ 200 μg/mL and 4-bromo and 4-chloro cinnamaldehydes exhibited anthelmintic property at 20 μg/mL against C. elegans. α-Methyl and trans-4-methyl cinnamaldehydes inhibited hyphal growth and cell aggregation. Scanning electron microscopy was employed to determine the surface architecture of C. albicans biofilm and cuticle of C. elegans, and confocal laser scanning microscopy was used to determine biofilm characteristics. The perturbation in gene expression of C. albicans was investigated using qRT-PCR analysis and α-methyl and trans-4-methyl cinnamaldehydes exhibited down-regulation of ECE1, IFD6, RBT5, UCF1, and UME6 and up-regulation of CHT4 and YWP1. Additionally, molecular interaction of these two molecules with UCF1 and YWP1 were revealed by molecular docking simulation. Our observations collectively suggest α-methyl and trans-4-methyl cinnamaldehydes are potent biofilm inhibitors and that 4-bromo and 4-chloro cinnamaldehydes are anthelmintic agents. Efforts are required to determine the range of potential therapeutic applications of cinnamaldehyde analogs.

Action of carvacrol in Salmonella Typhimurium biofilm: A proteomic study

Carvacrol presents action in Salmonella Typhimurium biofilms, however the antibiofilm mechanism of this compound has not been fully established yet. In the present study, the aim was to evaluate protein profile changes in S. Typhimurium biofilm treated with carvacrol. Proteomic analysis of treated versus untreated biofilm showed several changes in proteins involved with S. Typhimurium biofilm and antioxidant activity. The proteins DsbA (thiol: disulfide interchange protein DsbA), LuxS (S-ribosylhomocysteine lyase), DksA (RNA polymerase binding transcription factor DksA), and SODs (superoxide dismutases) A, B and C had their synthesis decreased after treatment with carvacrol. These proteins play a key role in S. Typhimurium biofilm formation, demonstrating the dynamic antibiofilm action of carvacrol. The differentially expressed proteins identified provide possible action targets for future studies in order to gain more insight into the mechanism of action of carvacrol on S. Typhimurium biofilm.

Cinnamaldehyde Promotes the Intestinal Barrier Functions and Reshapes Gut Microbiome in Early Weaned Rats

Cinnamaldehyde is an aromatic aldehyde isolated from the essential oil of cinnamon. It has been proved to possess various bioactivities such as anti-inflammation, anti-bacteria and antihypertensive. Nevertheless, early weaning could lead to intestinal stress, causing a range of intestinal health problems. The aim of this study is to explore the effects of cinnamaldehyde on gut barrier integrity, inflammatory responses, and intestinal microbiome of early weaned rats. In this study, treatment with cinnamaldehyde (100 or 200 mg/kg bodyweight/day) for 2 weeks significantly promoted the production of mucins in the colonic epithelial tissue of rats. Cinnamaldehyde supplementation significantly upregulated the expression of Muc2, TFF3 and the tight junction proteins (ZO-1, claudin-1, and occludin). Hematoxylin and eosin staining results showed that colonic histopathological changes were recovered by cinnamaldehyde supplementation. The mRNA expression of IL-6 and TNF-α were significantly decreased in the cinnamaldehyde groups while the TNF-α protein levels were significantly decreased in the two cinnamaldehyde groups. Cinnamaldehyde treatment obviously attenuated the activation of NF-κB signaling pathway in rat colonic tissue and suppressed the production of inflammatory cytokines. Furthermore, cinnamaldehyde supplementation remodeled the gut microbiome structure, at the genus level, Akkermansia, Bacteroides, Clostridium III, Psychrobacter, Intestinimonas were increased, whereas those of Ruminococcus, Escherichia/Shigella were obviously decreased in the cinnamaldehyde treated groups. These findings indicated that cinnamaldehyde could effectively enhance intestinal barrier integrity, ameliorate inflammatory responses and remodel gut microbiome in early weaned rats.

Proteomic Investigation of the Antibacterial Mechanism of trans-Cinnamaldehyde against Escherichia coli

Trans-Cinnamaldehyde (TC) is a widely used food additive, known for its sterilization, disinfection, and antiseptic properties. However, its antibacterial mechanism is not completely understood. In this study, quantitative proteomics was performed to investigate differentially expressed proteins (DEPs) in Escherichia coli in response to TC treatment. Bioinformatics analysis suggested aldehyde toxicity, acid stress, oxidative stress, interference of carbohydrate metabolism, energy metabolism, and protein translation as the bactericidal mechanism. E. coli BW25113ΔyqhD, ΔgldA, ΔbetB, ΔtktB, ΔgadA, ΔgadB, ΔgadC, and Δrmf were used to investigate the functions of DEPs through biochemical methods. The present study revealed that TC exerts its antibacterial effects by inducing the toxicity of its aldehyde group producing acid stress. These findings will contribute to the application of TC in the antibacterial field.

A systematic quantitative analysis of the published literature on the efficacy of essential oils as sanitizers in fresh leafy vegetables

This study carried out a systematic quantitative analysis of published literature on the efficacy of essential oils (EOs) as sanitizers in fresh leafy vegetables (FLVs). Efficacy of EO was measured by determining if their application could cause a reduction of microbial population in FLV, as well as by identifying experimental factors that might affect the achieved reduction levels. Data on efficacy of EO to reduce the microbial population and experimental conditions were collected from selected studies and compiled for a distribution and relational analysis. Reduction of an artificial inoculum and/or natural microbiota of FLV caused by 14 different EO were measured in 404 (73.8%) and 143 (26.2%) experiments, respectively. Results of quantitative analysis showed that EO are consistently effective to reduce microbial population in FLV either when the target microorganisms are forming an artificial inoculum or the natural microbiota, being overall similarly effective to or more effective than substances used ordinarily as sanitizers. EO were more effective to reduce the population of microorganisms forming an artificial inoculum than the natural microbiota. EO concentration and inoculum size had no significant effect on achieved reductions. Duration of sanitization treatment with EO had significant effect on achieved reductions and highest reductions were found when the sanitization time was >3 min. Although with the inherent variability in experimental designs found in available literature, the results of this quantitative analysis provide strong evidence that EO are promising candidates for use in strategies to sanitize FLV.

Proteomic analysis of the antimicrobial effects of sublethal concentrations of thymol on Salmonella enterica serovar Typhimurium

Salmonella enterica serovar Typhimurium is an important foodborne pathogen that causes serious and extensive food contamination as well as disease and death worldwide. Considering the increasing severity of antibiotic resistance, antibiotic alternatives are urgently needed. As a natural biocide and a component of some essential oils from herbs, thymol is capable of killing various bacteria through a potentially unique mechanism, although the targets of thymol have not been completely elucidated. In this study, the variation in the whole proteome of Salmonella after thymol stress was evaluated using the SWATH multiplex technique. The strain Salmonella Typhimurium CVCC541 was treated with a sublethal concentration (75 μg/mL) of thymol, which rapidly increased the permeability of bacterial membranes at the tested concentration. Thymol destroyed the integrity of the bacterial membrane, as observed by transmission electron microscopy. The proteomes of the treated and untreated cells were characterized after an 8-h treatment. The proteomic analysis of thymol-treated cells indicated that 144 proteins exhibited upregulation or downregulation compared with the control cells, particularly those involved in cellular structure and metabolism. The results of this study showed that thymol may play an antimicrobial role in altering the membrane permeability, virulence change, and antioxidant response of Salmonella Typhimurium. The results of the present study provide an improved understanding of the proteomic response of Salmonella Typhimurium to thymol stress, including the identification of promising targets for the future exploration of innovative approaches to control Salmonella Typhimurium.

Investigating the antimicrobial and antibiofilm effects of cinnamaldehyde against Campylobacter spp. using cell surface characteristics

Campylobacter species are known as biofilm-forming bacteria in food systems. The aim of this study was to evaluate the antimicrobial and antibiofilm effects of cinnamaldehyde against Campylobacter jejuni and Campylobacter coli isolated from chicken meat. The biofilm-forming C. jejuni and C. coli strains from chicken meat were investigated using minimum inhibitory concentration (MIC) and Campylobacter spp. characteristics. The MIC value was 31.25 µg/mL for the Campylobacter strains tested. Cinnamaldehyde had an inhibition and degradation effect on Campylobacter biofilms at concentrations > 15.63 µg/mL. Campylobacter strains treated with 15.63 µg/mL CA exhibited significantly decreased autoaggregation, motility, exopolysaccharide production, and soluble protein. In addition, Campylobacter biofilms formed on stainless steel were degraded following cinnamaldehyde treatment, as determined by scanning electron microscopy. Taken together, these results suggest that cinnamaldehyde constitutes a potential natural preservative against Campylobacter and a nontoxic biofilm remover that could be applied to control food poisoning in the poultry manufacturing-related food industry. PRACTICAL APPLICATION: Cinnamaldehyde was able to effectively remove the biofilm of Campylobacter in the small crack of stainless steel. Cinnamaldehyde has a potential to replace the synthetic antimicrobial and/or antibiofilm agent as well as has a positive influence on consumer concern for the food safety issues of the poultry industries.

A review of cinnamaldehyde and its derivatives as antibacterial agents

There is a continuing rise in the occurrence of multidrug-resistant bacterial infections. Antibiotic resistance to currently available antibiotics has become a global health issue leading to an urgent need for alternative antibacterial strategies. There has been a renewed interest in the development of antibacterial agents from natural sources, and trans-cinnamaldehyde is an example of a naturally occurring compound that has received significant attention in recent years. Trans-Cinnamaldehyde has been shown to possess substantial antimicrobial activity, as well as an array of other medicinal properties, and represents an intriguing hit compound from which a number of derivatives have been developed. In some cases, these derivatives have been shown to possess improved activity, not only compared to trans-cinnamaldehyde but also to commonly used antibiotics. Therefore, understanding the antibacterial mechanisms of action that these compounds elicit is imperative in order to facilitate their development and the development of new antibacterial agents that could exploit similar mechanistic approaches. The purpose of this review is to provide an overview of current knowledge on the antibacterial activity and mechanisms of action of cinnamaldehyde and its derivatives, and to highlight significant contributions made in this research area. It is hoped that the findings presented in this work will aid the future development of new antibacterial agents.

Environmental proteomic studies: closer step to understand bacterial biofilms

Advancement in proteome analytical techniques and the development of protein databases have been helping to understand the physiology and subtle molecular mechanisms behind biofilm formation in bacteria. This review is to highlight how the evolving proteomic approaches have revealed fundamental molecular processes underlying the formation and regulation of bacterial biofilms. Based on the survey of research reports available on differential expression of proteins in biofilms of bacterial from wide range of environments, four important cellular processes viz. metabolism, motility, transport and stress response that contribute to formation of bacterial biofilms are discussed. This review might answer how proteins related to these cellular processes contribute significantly in stabilizing biofilms of different bacteria in diverse environmental conditions.