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This chapter describes a step-by-step protocol for rapid serological quantification of global DNA methylation by enzyme-linked immunosorbent assay (ELISA) in plant tissue culture specimens. As a case study model, we used the coconut palm (Cocos nucifera), from which plumules were subjected to somatic embryogenesis followed by embryogenic calli multiplication. DNA methylation is one of the most common epigenetic markers in the regulation of gene expression. DNA methylation is generally associated with non-expressed genes, that is, gene silencing under certain conditions, and the degree of DNA methylation can be used as a marker of various physiological processes, both in plants and in animal cells. Methylation consists of adding a methyl radical to carbon 5 of the DNA cytosine base. Herein, the global DNA methylation was quantified by ELISA with antibodies against methylated cytosines using a commercial kit (Zymo-Research™). The method allowed the detection of methylation in total DNA extracts from coconut palm embryogenic calli (arising from somatic embryogenesis) cultivated in liquid or solid media by using antibodies against methylated cytosines and enzymatic development with a colorimetric substrate. Control samples of commercially provided Escherichia coli bacterial DNA with previously known methylation percentages were included in the ELISA test to construct an experimental methylation standard curve. The logarithmic regression of this E. coli standard curve allowed methylation quantification in coconut palm samples. The present ELISA methodology, applied to coconut palm tissue culture specimens, is promising for use in other plant species and botanical families. This chapter is presented in a suitable format for use as a step-by-step laboratory procedure manual, with theoretical introduction information, which makes it easy to apply the protocol in samples of any biological nature to evaluate DNA global methylation associated with any physiological process.

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The in vitro cultivation of M. leprae has not been possible since it was described as causing leprosy, and the limitation of animal models for clinical aspects makes studies on leprosy and bacteria-human host interaction a challenge. Our aim was to standardize the ex vivo skin model (hOSEC) to maintenance and study of M. leprae as an alternative animal model. Bacillary suspensions were inoculated into human skin explants and sustained in DMEM medium for 60 days. Explants were evaluated by RT-PCR-16SrRNA and cytokine gene expression. The viability and infectivity of bacilli recovered from explants (D28 and D60) were evaluated using the Shepard's model. All explants were RT-PCR-16SrRNA positive. The viability and infectivity of recovered bacilli from explants, analyzed after 5 months of inoculation in mice, showed an average positivity of 31%, with the highest positivity in the D28 groups (80%). Furthermore, our work showed different patterns in cytokine gene expression (TGF-ß, IL-10, IL-8, and TNF-α) in the presence of alive or dead bacilli. Although changes can be made to improve future experiments, our results have demonstrated that it is possible to use the hOSEC to maintain M. leprae for 60 days, interacting with the host system, an important step in the development of experimental models for studies on the biology of the bacillus, its interactions, and drug susceptibility.

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Sugarcane is used to produce sugar, ethanol, and other by-products, so it is considered one of the most important crops worldwide. Using temporary immersion systems for sugarcane micropropagation represents an alternative to reduce the labor force, increase plant development, and improve plant quality. Temporary immersion systems are semi-automated bioreactors designed for the large-scale propagation of tissues, embryos, and organs. These are temporarily exposed in a liquid culture medium under a specific time and immersion frequency. Using this protocol and a temporary immersion bioreactor, it is possible to achieve multiplication and rooting. The use of temporary immersion bioreactors improves the multiplication rate and the rooting of sugarcane, reducing the culture time, labor force, and reagents needed while maintaining high survival rates during acclimatization.

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The Guadalupe cypress (Cupressus guadalupensis S. Watson) is an endangered species included in the list of the NOM-059-SEMARNAT-2010. The presence of wild goats in the habitat has been the greatest threat to the propagation and survival of this species. Therefore, there is a need to generate propagation protocols that facilitate the regeneration of the species. Plant tissue culture offers various possibilities that can facilitate the regeneration of species under some risk. Temporary immersion systems have proven to be an option with various advantages in plant tissue culture, such as increasing the number of seedlings generated and reducing production times, compared to semisolid media. The objective of this chapter is to describe a protocol to propagate Guadalupe cypress tissues in a RITA® temporary immersion system.

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Plant growth regulators (PGR) are essential for somatic embryogenesis (SE) in different species, and Coffea canephora is no exception. In our study model, previously, we have been able to elucidate the participation of various genes involved in SE by using different strategies; however, until now, we have not used a proteomic approach. This research seeks to contribute to understanding the primary cellular pathways involved in developing SE in C. canephora. The process of our model consists of two stages: (1) preconditioning in MS medium with auxin (NAA) and cytokinin (KIN), and (2) induction in Yasuda liquid medium added with cytokinin (BA). Therefore, in this study, we analyzed different days of the SE induction process using shotgun label-free proteomics. An amount of 1630 proteins was found among different sampling days of the process, of which the majority were accumulated during the induction stage. We found that some of the most enriched pathways during this process were the biosynthesis of amino acids and secondary metabolites. Eighteen proteins were found related to auxin homeostasis and two to cytokinin metabolism, such as ABC, BIG, ILR, LOG, and ARR. Ten proteins and transcription factors related to SE were also identified, like SERK1, SKP1, nuclear transcription factor Y, MADS-box, and calreticulin, and 19 related to other processes of plant development, among which the 14-3-3 and PP2A proteins stand out. This is the first report on the proteomic approach to elucidate the mechanisms that operate during the induction of SE in C. canephora. So, our findings provide the groundwork for future, more in-depth research. Data are available via ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD047172.

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Anthurium magnificum Linden es una importante planta ornamental perteneciente a la familia Araceae. Esta especie es muy demandada como planta de maceta para la decoración de interiores y jardines, así como follaje de corte. Los métodos de propagación tradicionales en esta especie presentan ciertas desventajas por lo que no permiten satisfacer la creciente demanda. Estas limitantes convierten al cultivo de tejidos vegetales en el método más eficiente para propagar plantas de Anthurium magnificum a un ritmo más rápido que los métodos de propagación convencionales. En el cultivo de tejidos vegetales el nitrato de plata adicionado a los medios de cultivo actúa como un inhibidor de la acción del etileno y desempeña un papel crucial en la regulación de procesos fisiológicos esenciales de las plantas. El presente trabajo tuvo como objetivo determinar el efecto de diferentes concentraciones de nitrato de plata en el crecimiento in vitro de brotes de Anthurium magnificum. Para ello, se cultivaron brotes in vitro de Anthurium magnificum en medios de cultivo enriquecidos con diferentes concentraciones de nitrato de plata. Los resultados mostraron que los mayores valores en las variables altura de la planta, número de raíces y longitud de las raíces se obtuvieron en un medio de cultivo con 1,0 mg L-1 de nitrato de plata. En la variable área foliar de la planta los mayores valores se presentaron en los medios de cultivo que contenían nitrato de plata independientemente de la concentración empleada.

Anthurium magnificum Linden is an important ornamental plant belonging to the Araceae family. This species is in great demand as a pot plant for interior and garden decoration, as well as cut foliage. The traditional propagation methods in this species have certain disadvantages, which is why they cannot satisfy the growing demand. These limitations make plant tissue culture the most efficient method to propagate Anthurium magnificum plants at a faster rate than conventional propagation methods. In the culture of plant tissues, silver nitrate added to the culture media acts as an inhibitor of the action of ethylene and plays a crucial role in the regulation of essential physiological processes in plants. The objective of this work was to determine the effect of different concentrations of silver nitrate on the in vitro growth of Anthurium magnificum shoots. For this, in vitro shoots of Anthurium magnificum were cultivated in culture media enriched with different concentrations of silver nitrate. The results showed that the highest values in the variables plant height, number of roots and length of the roots were obtained in a culture medium with 1.0 mg L-1 of silver nitrate. In the variable leaf area of the plant, the highest values were presented in the culture media that contained silver nitrate, regardless of the concentration used.

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INTRODUCTION: Cecropia angustifolia Trécul. is a native Andean plant containing high levels of pentacyclic triterpenes (PTs), including several isobaric molecules that serve as chemical markers. Preclinical studies suggest that PTs positively modulate metabolic and vascular diseases. However, their low oral absorption reduces their bioactive effects. OBJECTIVE: The objective of this study was (1) to improve the absorption of PTs from C. angustifolia and (2) to establish a platform to produce biomass or botanical reference material using a strategy for their accumulation. METHODS: MALDI-TOF and UPLC-MS were used to characterize and quantify PTs in different matrices. An in vitro platform for PT production was established. Chemical profiles of triterpenes were also evaluated from wild and in vitro herbal material using TLC coupled with mass spectrometry. RESULTS: To overcome the low absorption of PTs, a premier raw material was used, which increased their bioavailability to 9.2%. Active ingredients in herbal material can vary, and there is an urgent need for standardized extracts using pharmacokinetics as an effective tool to reveal the dynamics of active ingredients in vivo. A temporary immersion system was produced as a promising platform with a total PT accumulation exceeding 50% of the content in the dry fraction, indicating it is a feasible mechanism to produce biomass or botanical reference material. CONCLUSIONS: Plant tissue culture is a promising eco-friendly technology for phytochemical production and a modern strategy to protect biodiversity in natural assets. Alternative and modern, yet environmentally friendly production methods are needed to meet the large demand for herbal products.

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Abstract Objective Our study aimed to elucidate the effect of PAI-1 (Plasminogen Activator Inhibitor-1) and t-PA (Tissue-type Plasminogen Activator) in tissue remodeling in nasal polyps patients. Methods Samples were streamed as early Nasal Polyps (eNP, n = 10) and inferior tissue from the same patient, mature Nasal Polyps (mNP, n = 14), and Control group (n = 15), respectively. Immunohistochemistry and immunofluorescence were applied to detect localization. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Western blot were used to measure different levels among three groups. The mNP tissue was cultured in vitro and treated with TGF-β1 (Transforming Growth Factor-beta 1) activator, TGF-β1 inhibitor (SB431542), and PAI-1 inhibitor (TM5275); then Western blot, qRT-PCR, and ELISA were used to assess changes. Results The immunohistochemistry and immunofluorescence showed that PAI-1 expression decreased in eNP and mNP, mainly in epithelium and glands. The transcriptional expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 were lower in eNP than IT while mNP group demonstrated lower mRNA expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 than Control group. In mNP tissue culture in vitro, TGF-β1 activator elevated t-PA, PAI-1, and Collagen1 with higher release of PAI-1 and Collagen1 in supernatant, whereas SB431542 suppressed above reactions; TM5275 lowered transcriptional and protein level of Collagen1 in supernatant. Conclusion Early Nasal polyps' formation in middle meatus mucous is related with fibrillation system PAI-1/t-PA and tissue remodeling; moreover, nasal polyps' development is regulated by TGF-β1-mediated PAI-1 reduction. Level of evidence 3b.

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Coffea arabica is one of the two most consumed coffee species in the world. Micropropagation through somatic embryogenesis has allowed the large-scale propagation of different coffee varieties. However, the regeneration of plants using this technique depends on the genotype. This study aimed to develop a protocol for the regeneration of C. arabica L. var. Colombia by somatic embryogenesis for its mass propagation. Foliar explants were cultured on Murashige and Skoog (MS) supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP), and phytagel for inducing somatic embryogenesis. In total, 90% of the explants formed embryogenic calli with a culture medium containing 2 mg L-1 of 2,4-D, 0.2 mg L-1 BAP, and 2.3 g L-1 phytagel. The highest number of embryos per gram of callus (118.74) was obtained in a culture medium containing 0.5 mg L-1 2,4-D, 1.1 mg L-1 BAP, and 5.0 g L-1 phytagel. In total, 51% of the globular embryos reached the cotyledonary stage when they were cultured on the growth medium. This medium contained 0.25 mg L-1 BAP, 0.25 mg L-1 indoleacetic acid (IAA), and 5.0 g L-1 of phytagel. The mixture of vermiculite:perlite (3:1) allowed 21% of embryos to become plants.

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OBJECTIVE: Our study aimed to elucidate the effect of PAI-1 (Plasminogen Activator Inhibitor-1) and t-PA (Tissue-type Plasminogen Activator) in tissue remodeling in nasal polyps patients. METHODS: Samples were streamed as early Nasal Polyps (eNP, n=10) and inferior tissue from the same patient, mature Nasal Polyps (mNP, n=14), and Control group (n=15), respectively. Immunohistochemistry and immunofluorescence were applied to detect localization. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Western blot were used to measure different levels among three groups. The mNP tissue was cultured in vitro and treated with TGF-ß1 (Transforming Growth Factor-beta 1) activator, TGF-ß1 inhibitor (SB431542), and PAI-1 inhibitor (TM5275); then Western blot, qRT-PCR, and ELISA were used to assess changes. RESULTS: The immunohistochemistry and immunofluorescence showed that PAI-1 expression decreased in eNP and mNP, mainly in epithelium and glands. The transcriptional expression and protein level of TGF-ß1/t-PA/PAI-1/Collagen1 were lower in eNP than IT while mNP group demonstrated lower mRNA expression and protein level of TGF-ß1/t-PA/PAI-1/Collagen1 than Control group. In mNP tissue culture in vitro, TGF-ß1 activator elevated t-PA, PAI-1, and Collagen1 with higher release of PAI-1 and Collagen1 in supernatant, whereas SB431542 suppressed above reactions; TM5275 lowered transcriptional and protein level of Collagen1 in supernatant. CONCLUSION: Early Nasal polyps' formation in middle meatus mucous is related with fibrillation system PAI-1/t-PA and tissue remodeling; moreover, nasal polyps' development is regulated by TGF-ß1-mediated PAI-1 reduction. LEVEL OF EVIDENCE: 3b.

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Collagenous tissues exhibit anisotropic optical properties such as birefringence and linear dichroism (LD) as a result of their structurally oriented supraorganization from the nanometer level to the collagen bundle scale. Changes in macromolecular order and in aggregational states can be evaluated in tendon collagen bundles using polarization microscopy. Because there are no reports on the status of the macromolecular organization in tendon explants, the objective of this work was to evaluate the birefringence and LD characteristics of collagen bundles in rat calcaneal tendons cultivated in vitro on substrates that differ in their mechanical stiffness (plastic vs. glass) while accompanying the expected occurrence of cell migration from these structures. Tendon explants from adult male Wistar rats were cultivated for 8 and 12 days on borosilicate glass coverslips (n = 3) and on nonpyrogenic polystyrene plastic dishes (n = 4) and were compared with tendons not cultivated in vitro (n = 3). Birefringence was investigated in unstained tendon sections using high-performance polarization microscopy and image analysis. LD was studied under polarized light in tendon sections stained with the dichroic dyes Ponceau SS and toluidine blue at pH 4.0 to evaluate the orientation of proteins and acid glycosaminoglycans (GAG) macromolecules, respectively. Structural remodeling characterized by the reduction in the macromolecular orientation, aggregation and alignment of collagen bundles, based on decreased average gray values concerned with birefringence intensity, LD and morphological changes, was detected especially in the tendon explants cultivated on the plastic substrate. These changes may have facilitated cell migration from the lateral regions of the explants to the substrates, an event that was observed earlier and more intensely upon tissue cultivation on the plastic substrate. The axial alignment of the migrating cells relative to the explant, which occurred with increased cultivation times, may be due to the mechanosensitive nature of the tenocytes. Collagen fibers possibly played a role as a signal source to cells, a hypothesis that requires further investigation, including studies on the dynamics of cell membrane receptors and cytoskeletal organization, and collagen shearing electrical properties.

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KEY MESSAGE: Plant regulatory noncoding RNAs (ncRNAs) have emerged as key modulators of gene expression during callus induction. Their further study may promote the design of innovative plant tissue culture protocols. The use of plants by humans has recently taken on a new and expanding insight due to the advent of genetic engineering technologies. In this context, callus cultures have shown remarkable potential for synthesizing valuable biomolecules, crop improvement, plant micropropagation, and biodiversity preservation. A crucial stage in callus production is the conversion of somatic cells into totipotent cells; compelling evidence indicates that stress factors, transcriptional regulators, and plant hormones can trigger this biological event. Besides, posttranscriptional regulators of gene expression might be essential participants in callus induction. However, research related to the analysis of noncoding RNAs (ncRNAs) that modulate callogenesis and plant cell dedifferentiation in vitro is still at an early stage. During the last decade, some relevant studies have enlightened the fact that different classes of ncRNAs, such as microRNAs (miRNAs), small interfering RNAs (siRNAs), and long noncoding RNAs (lncRNAs) are implicated in plant cell dedifferentiation through regulating the expression levels of diverse gene targets. Hence, understanding the molecular relevance of these ncRNAs in the aforesaid biological processes might represent a promising source of new biotechnological approaches for callus culture and plant improvement. In this current work, we review the experimental evidence regarding the prospective roles of ncRNAs in callus induction and plant cell dedifferentiation to promote this field of study.

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Salt stress is one of the most severe abiotic stresses affecting plant growth and development. The application of silicon (Si) is an alternative that can increase the tolerance of plants to various types of biotic and abiotic stresses. The objective was to evaluate salt stress's effect in vitro and Si's mitigation potential on Aechmea blanchetiana plants. For this purpose, plants already established in vitro were transferred to a culture medium with 0 or 14 µM of Si (CaSiO3). After growth for 30 days, a stationary liquid medium containing different concentrations of NaCl (0, 100, 200, or 300 µM) was added to the flasks. Anatomical and physiological analyses were performed after growth for 45 days. The plants cultivated with excess NaCl presented reduced root diameter and effective photochemical quantum yield of photosystem II (PSII) (ΦPSII) and increased non-photochemical dissipation of fluorescence (qN). Plants that grew with the presence of Si also had greater content of photosynthetic pigments and activity of the enzymes of the antioxidant system, as well as higher values of maximum quantum yield of PSII (FV/FM), photochemical dissipation coefficient of fluorescence (qP) and fresh weight bioaccumulation of roots and shoots. The anatomical, physiological and biochemical responses, and growth induced by Si mitigated the effect of salt stress on the A. blanchetiana plants cultivated in vitro, which can be partly explained by the tolerance of this species to grow in sandbank (Restinga) areas.

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In vitro germplasm conservation allows to extend the interval between subcultures without compromising the viability and genetic integrity of the plant, ensuring a backup of genotypes with high phytosanitary quality. Thus, this study aimed to verify the effect of four concentrations of Paclobutrazol® in inducing minimum growth in five Manihot esculenta accessions from the in vitro Active Germplasm Bank of Embrapa Cassava and Fruits. An experiment was installed using the Murashige and Skoog medium without addition and added with four concentrations of Paclobutrazol® (0.10, 0.20, 0.30, and 0.40 mg L-1), in five in vitro accessions of M. esculenta: BRS Jari (BGM 2041), Cigana (BGM 0264), BRS Poti Branca (BGM 2017), TME 14, and BRS Novo Horizonte. The statistical design was completely randomized in a 5 x 5 factorial scheme, with 15 repetitions. After 120 days of cultivation, the following variables were evaluated: plant height (cm), number of green leaves, number of senescent leaves, number of mini-cuttings, number of shoots, and fresh and dry mass of shoots and roots (mg). Paclobutrazol® caused a reduction in plant height and gain in root mass for all accessions, in addition to preserving the number of green leaves and decreasing leaf senescence for most genotypes. There was a strong dependence of the genotype in relation to the concentration of Paclobutrazol®. The concentration of 0.20 mg L-1 showed potential in the in vitro conservation of M. esculenta genotypes.(AU)

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Effective protocols for in vitro rooting for woody fruit trees are still a challenge for in vitro seedling production, especially when there is a need to insert new cultivars or rootstocks. These protocols are essential to accelerate studies in plant breeding programs and for seedling distribution. This study evaluated the use of 6-Benzylaminopurine (IBA) in in vitro rooting of Pyruscomunnis rootstocks, clones 'OHxF87' and Pyrodwarf. Explant exposure times (0, 24, 48, 72, and 96 hours) to 20 mg L-1 IBA were tested for in vitro rooting. The exposure to IBA resulted in rooting rates above 80%, surpassing some results reported in the literature. The 24-hour treatment provided 81,81% survival, leading to an average growth of five roots with 19 mm length, for 'OHxF87' rootstock. The same exposure time resulted in the highest survival rate (75%) and the highest mean root number, seven roots per plant with 10 mm length, for 'PDW' rootstock. Root formation did not occur in the absence of synthetic auxin. Therefore, it can be concluded that a 24-hour exposure at 20 mg L-1 IBA was sufficient to promote in vitro rooting in 'OHxF87' and Pyrodwarf rootstocks'.

Protocolos eficazes de enraizamento in vitro de frutíferas lenhosas ainda são um desafio para produção de mudas in vitro, especialmente quando há necessidade de inserção de novas cultivares ou porta-enxerto. Esses protocolos são essenciais para acelerar estudos nos programas de melhoramento genético e também para distribuição posterior das mudas. Nesse sentido, o objetivo deste estudo foi avaliar a utilização da 6-Benzilaminopurina no enraizamento in vitro de porta-enxerto Pirus comunnis, clones 'OHxF87' e Pyrodwarf. Para o enraizamento, foi testado o tempo de exposição dos explantes ao AIB. Para tanto, foram utilizados 20 mg L-1 do fitohormônio nas horas 0, 24, 48, 72 e 96 horas. A exposição ao AIB resultou em taxas de enraizamento acima de 80%, superando alguns resultados encontrados na literatura. Para o porta-enxerto 'OHxF87', o tratamento de 24 horas proporcionou 81,81% de sobrevivência, promovendo em média cinco raízes com comprimento de 19 mm. O mesmo tratamento para o porta-enxerto 'PDW' resultou na maior taxa de sobrevivência (75%), bem como no maior número médio de raízes, sete raízes por planta, com comprimento de 10 mm. Na ausência de auxina sintética, a formação de raízes não ocorreu. Assim sendo, podemos concluir que o tempo de exposição de 24 horas a 20 mg L-1 de IBA foi suficiente para promover o enraizamento de porta-enxertos Pyrus communis de 'OHxF87' e 'PDW'.

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This review aims to explore advanced reproductive technologies for male fertility preservation, underscoring the essential role that animal models have played in shaping these techniques through historical contexts and into modern applications. Rising infertility concerns have become more prevalent in human populations recently. The surge in male fertility issues has prompted advanced reproductive technologies, with animal models playing a pivotal role in their evolution. Historically, animal models have aided our understanding in the field, from early reproductive basic research to developing techniques like artificial insemination, multiple ovulation, and in vitro fertilization. The contemporary landscape of male fertility preservation encompasses techniques such as sperm cryopreservation, testicular sperm extraction, and intracytoplasmic sperm injection, among others. The relevance of animal models will undoubtedly bridge the gap between traditional methods and revolutionary next-generation reproductive techniques, fortifying our collective efforts in enhancing male fertility preservation strategies. While we possess extensive knowledge about spermatogenesis and its regulation, largely thanks to insights from animal models that paved the way for human infertility treatments, a pressing need remains to further understand specific infertility issues unique to humans. The primary aim of this review is to provide a comprehensive analysis of how animal models have influenced the development and refinement of advanced reproductive technologies for male fertility preservation, and to assess their future potential in bridging the gap between current practices and cutting-edge fertility techniques, particularly in addressing unique human male factor infertility.

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Protoplasts are an attractive explant source for biotechnological tools widely used on citrus genetic improvement, such as somatic hybridization and direct genetic transformation. These delicate and responsive materials are subjected to cell proliferation induction and differentiation of somatic embryos which further regenerate into entire plants. The isolation of viable protoplasts followed by regeneration of plants through somatic embryogenesis is an important methodology for breeding applications. The methods presented here can also be used as a reference for protoplast work in other species, followed by protocol optimization for different species/genotypes.

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Cassava is a staple food used in many countries around the world, despite deficiencies in micronutrients such as provitamin A carotenoids. Unfortunately, improvement of the cassava nutritional content by use of conventional breeding is slow and difficult. Therefore, there is an urgent need to develop and standardize protocols using biotechnological tools to improve cassava. The Alliance of Biodiversity International and the International Center for Tropical Agriculture (CIAT) have worked on cassava genetic transformation over the last 30 years. Here, we describe, step by step, the procedures used for genetic transformation of cassava variety TMS60444, to improve carotenoids and other traits. This protocol includes stock setup, reagents, media preparation, materials, and equipment, for the genetic transformation of embryogenic tissues. The main expected output in publishing this protocol is to provide the basis for a reproducible and reliable method to genetically modify and/or gene edit Latin American and Asian cassava varieties.

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Cellular invasion by Trypanosoma cruzi metacyclic trypomastigotes (MTs) or tissue culture trypomastigotes (TCTs) is a complex process involving host-parasite cellular and molecular interactions. Particularly, the involvement of host cell actin cytoskeleton during trypomastigote invasion is poorly investigated, and still, the results are controversial. In the present work, we compare side by side both trypomastigote forms and employ state-of-the-art live-cell imaging showing for the first time the dynamic mobilization of host cell actin cytoskeleton to MT and TCT invasion sites. Moreover, cytochalasin D, latrunculin B, and jasplakinolide-pretreated cells inhibited MT and TCT invasion. Furthermore, our results demonstrated that TCT invasion decreased in RhoA, Rac1, and Cdc-42 GTPase-depleted cells, whereas MT invasion decreased only in Cdc42-and RhoA-depleted cells. Interestingly, depletion of the three studied GTPases induced a scattered lysosomal distribution throughout the cytosol. These observations indicate that GTPase depletion is sufficient to impair parasite invasion despite the importance of lysosome spread in trypomastigote invasion. Together, our results demonstrate that the host cell actin cytoskeleton plays a direct role during TCT and MT invasion.

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In vitrooxidationisaproblem forsome herbaceous and woody species and can causedarkening of tissues and consequently death of explantsand plants Therefore, this study aimed to assess the effect of activated charcoal on in vitro yamcultivation, aiming at reducing or eliminating explant oxidation and optimizing the growth of the genotypes Dioscorea alata var.purpurea(Roxb.) A. Pouchet and Dioscorea rotundataPoir. Nodal segments of approximately 1 cm, extracted from plants previously grown in vitro, were introduced into test tubes containing 10 mL of 2GGC culture medium, plus 30 g L-1sucrose, solidified with 2.2 g L-1Phytagel®and pH adjusted to 5.8 before autoclaving, containing activated charcoal doses of 0, 1, 2, 3 and 4 g L-1. Plants were maintained for 90 days in a growth room, with temperature of 27 ± 1ºC, photon flux density of 30 µmol m-2s-1and photoperiod of 16 hours, after which their development variables were evaluated. Activated charcoal, at the concentration of 4 g L-1considerably promoted the best development of plants, and the species D. alatavar.purpureashowed higher means for all variables studied.(AU)

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