Shoot tip necrosis of in vitro plant cultures: a reappraisal of possible causes and solutions.

MAIN CONCLUSION: Shoot tip necrosis is a physiological condition that negatively impacts the growth and development of in vitro plant shoot cultures across a wide range of species. Shoot tip necrosis is a physiological condition and disorder that can arise in plantlets or shoots in vitro that results in death of the shoot tip. This condition, which can spread basipetally and affect the emergence of axillary shoots from buds lower down the stem, is due to the cessation of apical dominance. STN can occur at both shoot multiplication and rooting stages. One of the most common factors that cause STN is nutrient deficiency or imbalance. Moreover, the presence or absence of plant growth regulators (auxins or cytokinins) at specific developmental stages may impact STN. The cytokinin to auxin ratio within an in vitro plant can be modified by varying the concentration of cytokinins used in the culture medium. The supply of nutrients to in vitro shoots or plantlets might also affect their hormonal balance, thus modifying the occurrence of STN. High relative humidity within culture vessels and hyperhydricity are associated with STN. An adequate supply of calcium as the divalent cation (Ca2+) can hinder STN by inhibiting the accumulation of phenolic compounds and thus programmed cell death. Moreover, the level of Ca2+ affects auxin transport and ethylene production, and higher ethylene production, which can occur as a result of high relative humidity in or poor ventilation of the in vitro culture vessel, induces STN. High relative humidity can decrease the mobility of Ca2+ within a plant, resulting in Ca2+ deficiency and STN. STN of in vitro shoots or plantlets can be halted or reversed by altering the basal medium, mainly the concentration of Ca2+, adjusting the levels of auxins or cytokinins, or modifying culture conditions. This review examines the literature related to STN, seeks to discover the associated factors and relations between them, proposes practical solutions, and attempts to better understand the mechanism(s) underlying this condition in vitro.

Modeling of the Production of Lipid Microparticles Using PGSS® Technique.

Solid lipid microparticles (SLMPs) are attractive carriers as delivery systems as they are stable, easy to manufacture and can provide controlled release of bioactive agents and increase their efficacy and/or safety. Particles from Gas-Saturated Solutions (PGSS®) technique is a solvent-free technology to produce SLMPs, which involves the use of supercritical CO2 (scCO2) at mild pressures and temperatures for the melting of lipids and atomization into particles. The determination of the key processing variables is crucial in PGSS® technique to obtain reliable and reproducible microparticles, therefore the modelling of SLMPs production process and variables control are of great interest to obtain quality therapeutic systems. In this work, the melting point depression of a commercial lipid (glyceryl monostearate, GMS) under compressed CO2 was studied using view cell experiments. Based on an unconstrained D-optimal design for three variables (nozzle diameter, temperature and pressure), SLMPs were produced using the PGSS® technique. The yield of production was registered and the particles characterized in terms of particle size distribution. Variable modeling was carried out using artificial neural networks and fuzzy logic integrated into neurofuzzy software. Modeling results highlight the main effect of temperature to tune the mean diameter SLMPs, whereas the pressure-nozzle diameter interaction is the main responsible in the SLMPs size distribution and in the PGSS® production yield.

Technologies and Formulation Design of Polysaccharide-Based Hydrogels for Drug Delivery.

Polysaccharide-based hydrogel particles (PbHPs) are very promising carriers aiming to control and target the release of drugs with different physico-chemical properties. Such delivery systems can offer benefits through the proper encapsulation of many drugs (non-steroidal and steroidal anti-inflammatory drugs, antibiotics, etc) ensuring their proper release and targeting. This review discusses the different phases involved in the production of PbHPs in pharmaceutical technology, such as droplet formation (SOL phase), sol-gel transition of the droplets (GEL phase) and drying, as well as the different methods available for droplet production with a special focus on prilling technique. In addition, an overview of the various droplet gelation methods with particular emphasis on ionic cross-linking of several polysaccharides enabling the formation of particles with inner highly porous network or nanofibrillar structure is given. Moreover, a detailed survey of the different inner texture, in xerogels, cryogels or aerogels, each with specific arrangement and properties, which can be obtained with different drying methods, is presented. Various case studies are reported to highlight the most appropriate application of such systems in pharmaceutical field. We also describe the challenges to be faced for the breakthrough towards clinic studies and, finally, the market, focusing on the useful approach of safety-by-design (SbD).

Deciphering the virulence of Mycobacterium avium subsp. paratuberculosis isolates in animal macrophages using mathematical models.

Understanding why pathogenic Mycobacterium avium subsp. paratuberculosis (Map) isolates cause disparate disease outcomes with differing magnitudes of severity is important in designing and implementing new control strategies. We applied a suite of mathematical models: i) general linear, ii) and neurofuzzy logic, to explain how the host of origin of several Map isolates, Map genotype, host, macrophage-based in vitro model and time post-infection contributed to the infection. A logistic growth ordinary differential equation (ODE) model was applied to estimate within macrophage growth rates for the different Map isolates. The models revealed different susceptibilities of bovine and ovine macrophages to Map infection and confirmed distinct virulence profiles for the isolates, judged by their ability to grow within macrophages. Ovine macrophages were able to internalize Map isolates more efficiently than bovine macrophages. While bovine macrophages were able to internalize Map isolates from cattle with more efficiency, ovine macrophages were more efficient in internalizing ovine isolates. Overall, Map isolates from goat and sheep grew minimally within macrophages or did not grow but were able to persist by maintaining its initial population. In contrast, the ability of the bovine isolates and the non-domesticated animal isolates to grow to higher CFU numbers within macrophages suggests that these isolates are more virulent than the sheep and goat isolates, or that these isolates are better adapted to infect domestic ruminants. Overall, our study confirms the different virulence levels for the Map isolates and susceptibility profiles of host macrophages, which is crucial in increasing our understanding of Map infection.

Current Stage of Marine Ceramic Grafts for 3D Bone Tissue Regeneration.

Bioceramic scaffolds are crucial in tissue engineering for bone regeneration. They usually provide hierarchical porosity, bioactivity, and mechanical support supplying osteoconductive properties and allowing for 3D cell culture. In the case of age-related diseases such as osteoarthritis and osteoporosis, or other bone alterations as alveolar bone resorption or spinal fractures, functional tissue recovery usually requires the use of grafts. These bone grafts or bone void fillers are usually based on porous calcium phosphate grains which, once disposed into the bone defect, act as scaffolds by incorporating, to their own porosity, the intergranular one. Despite their routine use in traumatology and dental applications, specific graft requirements such as osteoinductivity or balanced dissolution rate are still not completely fulfilled. Marine origin bioceramics research opens the possibility to find new sources of bone grafts given the wide diversity of marine materials still largely unexplored. The interest in this field has also been urged by the limitations of synthetic or mammalian-derived grafts already in use and broadly investigated. The present review covers the current stage of major marine origin bioceramic grafts for bone tissue regeneration and their promising properties. Both products already available on the market and those in preclinical phases are included. To understand their clear contribution to the field, the main clinical requirements and the current available biological-derived ceramic grafts with their advantages and limitations have been collected.

Mesenchymal Stem Cells in Homeostasis and Systemic Diseases: Hypothesis, Evidences, and Therapeutic Opportunities.

Mesenchymal stem cells (MSCs) are present in all organs and tissues, playing a well-known function in tissue regeneration. However, there is also evidence indicating a broader role of MSCs in tissue homeostasis. In vivo studies have shown MSC paracrine mechanisms displaying proliferative, immunoregulatory, anti-oxidative, or angiogenic activity. In addition, recent studies also demonstrate that depletion and/or dysfunction of MSCs are associated with several systemic diseases, such as lupus, diabetes, psoriasis, and rheumatoid arthritis, as well as with aging and frailty syndrome. In this review, we hypothesize about the role of MSCs as keepers of tissue homeostasis as well as modulators in a variety of inflammatory and degenerative systemic diseases. This scenario opens the possibility for the use of secretome-derived products from MSCs as new therapeutic agents in order to restore tissue homeostasis, instead of the classical paradigm "one disease, one drug".

Spermidine cross-linked hydrogels as a controlled release biomimetic approach for cloxacillin.

The intrinsic ability of albumin to bind active substances in the physiological fluids has been explored to endow hydrogels with improved capability to regulate drug release. To develop such biomimetic-functional hydrogels, it is critical that albumin conformation is not altered and that the protein remains retained inside the hydrogel keeping its conformational freedom, i.e., it should be not chemically cross-linked. Thus, the hydrogels were prepared with various proportions of albumin by physical cross-linking of anionic polysaccharides (gellan gum and chondroitin sulfate) with the cationic endogen polyamine spermidine under mild conditions in order to prevent albumin denaturation. Texture and swelling properties of hydrogels with various compositions were recorded, and the effect of the preparation variables was evaluated applying neurofuzzy logic tools for hydrogels prepared with and without albumin and associating the antibiotic cloxacillin. Developed hydrogel systems were extensively analyzed by means of nuclear magnetic resonance (NMR) to determine weak-to-medium and strong binding modes and the equilibrium constants of the albumin-cloxacillin association. NMR techniques were also employed to demonstrate the successful modulation of the cloxacillin release from the albumin-containing hydrogels. In vitro microbiological tests carried out with Staphylococcus aureus and Staphylococcus epidermidis confirmed the interest of the albumin-containing hydrogels as efficient platforms for cloxacillin release in its bioactive form.

Computer modeling assisted design of monodisperse PLGA microspheres with controlled porosity affords zero order release of an encapsulated macromolecule for 3 months.

PURPOSE: The aim of this study was the development of poly(D,L-lactide-co-glycolide) (PLGA) microspheres with controlled porosity, to obtain microspheres that afford continuous release of a macromolecular model compound (blue dextran). METHODS: PLGA microspheres with a size of around 40 µm and narrow size distribution (span value of 0.3) were prepared with a double emulsion membrane emulsification method. Gene expression programming (GEP) analysis was applied to design and formulate a batch of microspheres with controlled porosity that shows continuous release of blue dextran. RESULTS: Low porous microspheres with a high loading efficiency were formed at high polymer concentrations (30% w/w in the oil phase) and were characterized with a burst release <10% and a three-phasic release profile of blue dextran. Increasing porosity (10% w/w polymer concentrations), a sustained release of blue dextran was obtained albeit with up to 40% of burst release. The desired formulation, calculated by GEP, resulted in microspheres with 72% loading efficiency and intermediate porosity. Blue dextran was indeed released continuously in almost a zero order manner over a period of 3 months after an initial small burst release of 9%. CONCLUSIONS: By fine-tuning the porosity, the release profile of PLGA microspheres for macromolecules can be predicted and changed from a three-phasic to a continuous release.

Fighting antibiotic resistance in the local management of bovine mastitis.

Bovine mastitis is a widespread infectious disease with a significant economic burden, accounting for 80 % of the antibiotic usage in dairy animals. In recent years, extensive research has focused on using biomimetic approaches such as probiotics, bacteriocins, bacteriophages, or phytochemicals as potential alternatives to antibiotics. The local administration of therapeutic molecules through the intramammary route is one of the most commonly strategies to manage bovine mastitis. This review highlights the most important findings in this field and discusses their local application in mastitis therapy. In contrast to antibiotics, the proposed alternatives are not limited to promote bacterial death but consider other factors associated to the host microenvironments. To this end, the proposed biomimetic strategies can modulate different stages of infection by modifying the local microbiota, preventing oxidative stress, reducing bacterial adhesion to epithelial cells, modulating the immune response, or mediating the inflammatory process. Numerous in vitro studies support the antimicrobial, antibiofilm or antioxidant properties of these alternatives. However, in vivo studies incorporating these components within pharmaceutical formulations with potential clinical application are limited. The development of secure, stable, and effective drug delivery systems based on the proposed options is necessary to achieve real alternatives to antibiotics in the clinic.

Engineering mannose-functionalized nanostructured lipid carriers by sequential design using hybrid artificial intelligence tools.

Nanostructured lipid carriers (NLCs) hold significant promise as drug delivery systems (DDS) owing to their small size and efficient drug-loading capabilities. Surface functionalization of NLCs can facilitate interaction with specific cell receptors, enabling targeted cell delivery. Mannosylation has emerged as a valuable tool for increasing the ability of nanoparticles to be recognized and internalized by macrophages. Nevertheless, the design and development of functionalized NLC is a complex task that entails the optimization of numerous variables and steps, making the process challenging and time-consuming. Moreover, no previous studies have been focused on evaluating the functionalization efficiency. In this work, hybrid Artificial Intelligence technologies are used to help in the design of mannosylated drug loaded NLCs. Artificial neural networks combined with fuzzy logic or genetic algorithms were employed to understand the particle formation processes and optimize the combinations of variables for the different steps in the functionalization process. Mannose was chemically modified to allow, for the first time, functionalization efficiency quantification and optimization. The proposed sequential methodology has enabled the design of a robust procedure for obtaining stable mannosylated NLCs with a uniform particle size distribution, small particle size (< 100 nm), and a substantial positive zeta potential (> 20mV). The incorporation of mannose on the surfaces of these DDS following the established protocols achieved > 85% of functionalization efficiency. This high effectiveness should enhance NLC recognition and internalization by macrophages, thereby facilitating the treatment of chronic inflammatory diseases.

Effect of polymer composition on rheological and degradation properties of temperature-responsive gelling systems composed of acyl-capped PCLA-PEG-PCLA.

In this study, the ability to modulate the rheological and degradation properties of temperature-responsive gelling systems composed of acyl-capped poly(ε-caprolactone-co-lactide)-b-poly(ethylene glycol)-b-poly(ε-caprolactone-co-lactide) (PCLA-PEG-PCLA) triblock copolymers was investigated. Eight polymers with varying molecular weight of PCLA, caproyl/lactoyl ratio (CL/LA) and capped with either acetyl- or propionyl-groups were synthesized by ring-opening polymerization of L-lactide and ε-caprolactone in toluene using PEG as initiator and tin(II) 2-ethylhexanoate as catalyst, and subsequently reacted in solution with an excess of acyl chloride to yield fully acyl-capped PCLA-PEG-PCLA. The microstructure of the polymers was determined by (1)H NMR, and the thermal properties and crystallinity of the polymers in dry state and in 25 wt % aqueous systems were studied by differential scanning calorimetry and X-ray diffraction. Rheological and degradation/dissolution properties of aqueous systems composed of the polymers in 25 wt % aqueous systems were studied. (1)H NMR analysis revealed that the monomer sequence in the PCLA blocks was not fully random, resulting in relatively long CL sequences, even though transesterification was demonstrated by the enrichment with lactoyl units and the presence of PEG-OH end groups. Except the most hydrophilic polymer composed of acetyl-capped PCLA1400-PEG1500-PCLA1400 having a CL/LA molar ratio of 2.5, the polymers at 25 wt % in buffer were sols below room temperature and transformed into gels between room temperature and 37 °C, which makes them suitable as temperature-responsive gelling systems for drug delivery. Over a period of weeks at 37 °C, the systems containing polymers with long CL sequences (~8 CL) and propionyl end-groups became semicrystalline as shown by X-ray diffraction analysis. Degradation of the gels by dissolution at 37 °C took 100-150 days for the amorphous gels and 250-300 days for the semicrystalline gels. In conclusion, this study shows that changes in the polymer composition allow an easy but significant modulation of rheological and degradation properties.

Rationalized design to explore the full potential of PLGA microspheres as drug delivery systems.

Polymeric microparticles are widely used as drug delivery platforms either alone or embedded in more complex structures for regenerative medicine. Emulsion-solvent evaporation is the most extensively used technique for microparticles preparation. Despite the apparent simplicity of this method, there is no general procedure for producing microparticles of predictable characteristics (particle size, size distribution, encapsulation efficiency, and drug loading). Hybrid systems such as neurofuzzy logic allow identifying relationships between inputs and outputs, expressing the generated mathematical models through rules in linguistic format. In this work, the relationships between the variables involved in the emulsion-solvent evaporation process and the quality parameters of PLGA microparticles as drug delivery systems were established. Neurofuzzy logic software was able to generate models of high predictability (> 85%) for the microspheres properties namely particle size, size distribution, encapsulation efficiency and drug loading. Moreover, the generated sets of IF-THEN rules allowed to dictate general guidelines to better select the PLGA microparticles formulation parameters. This approach would be of great interest as a starting point to set-up protocols for the development of PLGA microparticles obtained by emulsion-solvent evaporation for many applications.

Aerogels as Carriers for Oral Administration of Drugs: An Approach towards Colonic Delivery.

Polysaccharide aerogels have emerged as a highly promising technology in the field of oral drug delivery. These nanoporous, ultralight materials, derived from natural polysaccharides such as cellulose, starch, or chitin, have significant potential in colonic drug delivery due to their unique properties. The particular degradability of polysaccharide-based materials by the colonic microbiota makes them attractive to produce systems to load, protect, and release drugs in a controlled manner, with the capability to precisely target the colon. This would allow the local treatment of gastrointestinal pathologies such as colon cancer or inflammatory bowel diseases. Despite their great potential, these applications of polysaccharide aerogels have not been widely explored. This review aims to consolidate the available knowledge on the use of polysaccharides for oral drug delivery and their performance, the production methods for polysaccharide-based aerogels, the drug loading possibilities, and the capacity of these nanostructured systems to target colonic regions.

Vancomycin-Loaded 3D-Printed Polylactic Acid-Hydroxyapatite Scaffolds for Bone Tissue Engineering.

The regeneration of bone remains one of the main challenges in the biomedical field, with the need to provide more personalized and multifunctional solutions. The other persistent challenge is related to the local prevention of infections after implantation surgery. To fulfill the first one and provide customized scaffolds with complex geometries, 3D printing is being investigated, with polylactic acid (PLA) as the biomaterial mostly used, given its thermoplastic properties. The 3D printing of PLA in combination with hydroxyapatite (HA) is also under research, to mimic the native mechanical and biological properties, providing more functional scaffolds. Finally, to fulfill the second one, antibacterial drugs locally incorporated into biodegradable scaffolds are also under investigation. This work aims to develop vancomycin-loaded 3D-printed PLA-HA scaffolds offering a dual functionality: local prevention of infections and personalized biodegradable scaffolds with osseointegrative properties. For this, the antibacterial drug vancomycin was incorporated into 3D-printed PLA-HA scaffolds using three loading methodologies: (1) dip coating, (2) drop coating, and (3) direct incorporation in the 3D printing with PLA and HA. A systematic characterization was performed, including release kinetics, Staphylococcus aureus antibacterial/antibiofilm activities and cytocompatibility. The results demonstrated the feasibility of the vancomycin-loaded 3D-printed PLA-HA scaffolds as drug-releasing vehicles with significant antibacterial effects for the three methodologies. In relation to the drug release kinetics, the (1) dip- and (2) drop-coating methodologies achieved burst release (first 60 min) of around 80-90% of the loaded vancomycin, followed by a slower release of the remaining drug for up to 48 h, while the (3) 3D printing presented an extended release beyond 7 days as the polymer degraded. The cytocompatibility of the vancomycin-loaded scaffolds was also confirmed.

Temperature-sensitive gels for intratumoral delivery of ß-lapachone: effect of cyclodextrins and ethanol.

This work evaluated the potential of Pluronics (varieties F127 and P123) in combination with solubilizing agents to be used as syringeable in situ gelling depots of intratumoral ß-lapachone (ßLAP). Pluronic dispersions prepared at various concentrations in the absence and the presence of ethanol and randomly methylated ß-cyclodextrin (RMßCD) were characterized regarding their rheological properties, drug solubilization capacity, and in vitro release. Pluronic F127 (18-23%) formulations combined high ability to solubilize ßLAP (enhancement solubility factor up to 50), adequate gel temperature range (over 25 °C), and gel strength at 37 °C enough to guarantee the permanence of the formulation in the administration site for a period of time. ßLAP release rate was finely tuned by the concentration of the polymer and the addition of RMßCD (diffusion coefficient ranging between 9 and 69 µg · cm(-2)). The ethanol increases ßLAP release rate but simultaneously led to weak gels. This paper shows that ßLAP formulations involving temperature-reversible Pluronic gels may be suitable for intratumoral drug delivery purposes.

Fast dissolving ß-lapachone particles and tablets: an approach using surface adsorption technique.

BACKGROUND: ß-lapachone (ßLAP) is obtained from natural resources with promising preliminary results against the etiologic agent of Chagas disease. ßLAP activity is associated with generation of free radical and inhibition of nucleic acids and protein synthesis leading an outstanding antichagasic action. Low water solubility and large therapeutic doses constitute the main problems to overcome in the development of dosage forms of this drug. OBJECTIVE: The purpose of the present research was to enhance the limited dissolution rate of ßLAP by promoting the spontaneous crystalline growth of ßLAP on the surface of an inert excipient. METHODS: Physicochemical characterization of the particles was carried out as well as the drug dissolution rate. Drug adsorbed particles were compared to the drug as supplied and its physical mixtures with the inner excipient. The utility of the ßLAP adsorbed particles in the development of tablets obtained by direct compression were also evaluated. RESULTS: Particles produced by spontaneous crystalline growth of ßLAP on microcrystalline cellulose (MCC) hydrophilic surface showed mean diameters between 55-65 µm and fast drug dissolution rate (90% drug dissolved at 50 min). Neither physical nor chemical instability of the drug were detected after the drug adsorption procedure. The compression process does not extensively deteriorate the dissolution behaviour of the systems when an adequate compression pressure is used. CONCLUSIONS: Surface adsorption technique offers a simple way to produce ßLAP powder and tablets with improved dissolution rate for oral administration.

Sublingual Boosting with a Novel Mucoadhesive Thermogelling Hydrogel Following Parenteral CAF01 Priming as a Strategy Against Chlamydia trachomatis.

Chlamydia trachomatis is the most prevalent sexually transmitted disease of bacterial origin. The high number of asymptomatic cases makes it difficult to stop the transmission, requiring vaccine development. Herein, a strategy is proposed to obtain local genital tract immunity against C. trachomatis through parenteral prime and sublingual boost. Subcutaneous administration of chlamydia CTH522 subunit vaccine loaded in the adjuvant CAF01 is combined with sublingual administration of CTH522 loaded in a novel thermosensitive and mucoadhesive hydrogel. Briefly, a ternary optimized hydrogel (OGEL) with desirable biological and physicochemical properties is obtained using artificial intelligence techniques. This formulation exhibits a high gel strength and a strong mucoadhesive, adhesive and cohesive nature. The thermosensitive properties of the hydrogel facilitate application under the tongue. Meanwhile the fast gelation at body temperature together with rapid antigen release should avoid CTH522 leakage by swallowing and increase the contact with sublingual tissue, thus promoting absorption. In vivo studies demonstrate that parenteral-sublingual prime-boost immunization, using CAF01 and OGEL as CTH522 vaccine carriers, shows a tendency to increase cellular (Th1/Th17) immune responses when compared to mucosal or parenteral vaccination alone. Furthermore, parenteral prime with CAF01/CTH522 followed by sublingual boosting with OGEL/CTH522 elicits a local IgA response in the genital tract.

Artificial Neural Networks Elucidated the Essential Role of Mineral Nutrients versus Vitamins and Plant Growth Regulators in Achieving Healthy Micropropagated Plants.

The design of an adequate culture medium is an essential step in the micropropagation process of plant species. Adjustment and balance of medium components involve the interaction of several factors, such as mineral nutrients, vitamins, and plant growth regulators (PGRs). This work aimed to shed light on the role of these three components on the plant growth and quality of micropropagated woody plants, using Actinidia arguta as a plant model. Two experiments using a five-dimensional experimental design space were defined using the Design of Experiments (DoE) method, to study the effect of five mineral factors (NH4NO3, KNO3, Mesos, Micros, and Iron) and five vitamins (Myo-inositol, thiamine, nicotinic acid, pyridoxine, and vitamin E). A third experiment, using 20 combinations of two PGRs: BAP (6-benzylaminopurine) and GA3 (gibberellic acid) was performed. Artificial Neural Networks (ANNs) algorithms were used to build models with the whole database to determine the effect of those components on several growth and quality parameters. Neurofuzzy logic allowed us to decipher and generate new knowledge on the hierarchy of some minerals as essential components of the culture media over vitamins and PRGs, suggesting rules about how MS basal media formulation could be modified to assess the quality of micropropagated woody plants.

Using machine learning to link the influence of transferred Agrobacterium rhizogenes genes to the hormone profile and morphological traits in Centella asiatica hairy roots.

Hairy roots are made after the integration of a small set of genes from Agrobacterium rhizogenes in the plant genome. Little is known about how this small set is linked to their hormone profile, which determines development, morphology, and levels of secondary metabolite production. We used C. asiatica hairy root line cultures to determine the putative links between the rol and aux gene expressions with morphological traits, a hormone profile, and centelloside production. The results obtained after 14 and 28 days of culture were processed via multivariate analysis and machine-learning processes such as random forest, supported vector machines, linear discriminant analysis, and neural networks. This allowed us to obtain models capable of discriminating highly productive root lines from their levels of genetic expression (rol and aux genes) or from their hormone profile. In total, 12 hormones were evaluated, resulting in 10 being satisfactorily detected. Within this set of hormones, abscisic acid (ABA) and cytokinin isopentenyl adenosine (IPA) were found to be critical in defining the morphological traits and centelloside content. The results showed that IPA brings more benefits to the biotechnological platform. Additionally, we determined the degree of influence of each of the evaluated genes on the individual hormone profile, finding that aux1 has a significant influence on the IPA profile, while the rol genes are closely linked to the ABA profile. Finally, we effectively verified the gene influence on these two specific hormones through feeding experiments that aimed to reverse the effect on root morphology and centelloside content.

Neurofuzzy logic predicts a fine-tuning metabolic reprogramming on elicited Bryophyllum PCSCs guided by salicylic acid.

Novel approaches to the characterization of medicinal plants as biofactories have lately increased in the field of biotechnology. In this work, a multifaceted approach based on plant tissue culture, metabolomics, and machine learning was applied to decipher and further characterize the biosynthesis of phenolic compounds by eliciting cell suspension cultures from medicinal plants belonging to the Bryophyllum subgenus. The application of untargeted metabolomics provided a total of 460 phenolic compounds. The biosynthesis of 164 of them was significantly modulated by elicitation. The application of neurofuzzy logic as a machine learning tool allowed for deciphering the critical factors involved in the response to elicitation, predicting their influence and interactions on plant cell growth and the biosynthesis of several polyphenols subfamilies. The results indicate that salicylic acid plays a definitive genotype-dependent role in the elicitation of Bryophyllum cell cultures, while methyl jasmonate was revealed as a secondary factor. The knowledge provided by this approach opens a wide perspective on the research of medicinal plants and facilitates their biotechnological exploitation as biofactories in the food, cosmetic and pharmaceutical fields.