Chloroplast Isolation in Agavaceas.

Chloroplast isolation protocols have been extensively developed for various species of plants, particularly model organisms with easily manipulable physical characteristics. However, succulent plants, such as Agave angustifolia Haw., which possess adaptations for arid environments like the Crassulacean acid metabolism (CAM) and a thicker cuticle, have received less attention, resulting in a potential knowledge gap. This chapter presents a specialized protocol focusing on isolating chloroplast from A. angustifolia, a species exhibiting adaptations to arid conditions and holding ecological and economic significance due to its role in producing bacanora and mezcal beverages. By successfully isolating chloroplast from A. angustifolia plant growth in ex vitro and in vitro conditions, this protocol enables comprehensive future analyses to elucidate metabolic processes and explore potential applications in related species. Consequently, this research aims to bridge this knowledge gap in chloroplast isolation for succulent plants, providing new insights for future investigations in the field.

Effects of Chia Seeds on Growth Performance, Carcass Traits and Fatty Acid Profile of Lamb Meat.

The aim of this work was to supplement a diet with chia seeds (Salvia hispanica L.) based on the requirements of finishing lambs for meat, and to analyze biometric parameters and fatty acid profiles in meat. Eighteen male Rambouillet lambs with a bodyweight of 25 kg were used. Animals were kept in individual pens with water and feed provided ad libitum. Three finishing diets were designed with the inclusion of 0, 50 and 100 g dry matter chia seeds and divided among the animals (n = 6). The experimental period lasted 60 days. The weights of the individual lambs were recorded every 14 days. At the end of the experiment, the animals were slaughtered and the weights of the hot carcasses and non-meat components were registered. In addition, an analysis of the fatty acid composition was carried out in the muscles (Longissimus thoracis). The total weight gain and average daily gain displayed significant differences (p < 0.05). Initial and final bodyweights, such as the dry matter intake, did not display differences. The fatty acid profile of the meat tended to decrease the SFA (stearic acid) and increase MUFA (oleic acid) (p < 0.0001) when chia seeds were added to the lamb diets. In conclusion, chia seed supplementation did not increase meat production or other biometric parameters; however, it modified the fatty acid profile in L. thoracis.

The Banana MaWRKY18, MaWRKY45, MaWRKY60 and MaWRKY70 Genes Encode Functional Transcription Factors and Display Differential Expression in Response to Defense Phytohormones.

WRKY transcription factors (TFs) play key roles in plant defense responses through phytohormone signaling pathways. However, their functions in tropical fruit crops, especially in banana, remain largely unknown. Several WRKY genes from the model plants rice (OsWRKY45) and Arabidopsis (AtWRKY18, AtWRKY60, AtWRKY70) have shown to be attractive TFs for engineering disease resistance. In this study, we isolated four banana cDNAs (MaWRKY18, MaWRKY45, MaWRKY60, and MaWRKY70) with homology to these rice and ArabidopsisWRKY genes. The MaWRKY cDNAs were isolated from the wild banana Musa acuminata ssp. malaccensis, which is resistant to several diseases of this crop and is a progenitor of most banana cultivars. The deduced amino acid sequences of the four MaWRKY cDNAs revealed the presence of the conserved WRKY domain of ~60 amino acids and a zinc-finger motif at the N-terminus. Based on the number of WRKY repeats and the structure of the zinc-finger motif, MaWRKY18 and MaWRKY60 belong to group II of WRKY TFs, while MaWRKY45 and MaWRKY70 are members of group III. Their corresponding proteins were located in the nuclei of onion epidermal cells and were shown to be functional TFs in yeast cells. Moreover, expression analyses revealed that the majority of these MaWRKY genes were upregulated by salicylic acid (SA) or methyl jasmonate (MeJA) phytohormones, although the expression levels were relatively higher with MeJA treatment. The fact that most of these banana WRKY genes were upregulated by SA or MeJA, which are involved in systemic acquired resistance (SAR) or induced systemic resistance (ISR), respectively, make them interesting candidates for bioengineering broad-spectrum resistance in this crop.

Clinical performance of the Osia™ system, a new active osseointegrated implant system. Results from a prospective clinical investigation.

Background: Bone-conduction hearing implants are standard of care devices.Aims/Objectives: Evaluation of a new active magnetic bone-conduction hearing implant: Cochlear Osia™ system.Material and methods: This device uses a transcutaneous connection between an external sound-processor and an osseointegrated implant that generates vibrations using a piezoelectricity-based internal bone-conduction system. Nine patients with conductive-hearing loss were implanted. Surgical efficacy, hearing performance and quality-of-life were evaluated. Hearing performance in quiet and in noise was compared with unaided hearing and hearing with the Baha 5 Power® Sound Processor on a softband.Results: Surgery and healing were uneventful. Statistically significant improvements in audibility, speech-understanding, speech-recognition and quality-of-sound in noise and quiet were found for the Osia™ compared to preoperative unaided hearing and aided hearing with the Baha 5 Power® Sound Processor on a softband. The active vibration system provided improvement at low and high frequencies. At 6 months postoperatively, all patients continue to use the device.Conclusions and significance: The Osia™ is safe and effective, improving speech-recognition in quiet and in noise, at low and high frequencies, thus delivering better quality-of-hearing than passive devices.

Assessment of molecular and epigenetic changes in the albinism of Agave angustifolia Haw.

Albinism in plants is a rare phenomenon that occurs in nature and is characterized by the total or partial loss of photosynthetic pigments. Although progress has been made in understanding the nature of this phenomenon, the precise causes and biological basis are still unexplored. Here, we study the genetic and epigenetic differences between green (G), variegated (V) and albino (A) A. angustifolia Haw. plantlets obtained by in vitro propagation in order to present new insights into albinism from a plant system that offers a unique set of biological phenotypic characteristics. Low transcript levels of genes involved in carotenoids and photosynthesis such as PSY, PDS, LCYƐ, rubS, PEPCase and LHCP suggest a disruption in these processes in albino plants. Due to a high level of genetic similarity being found between the three phenotypes, we analyzed global DNA methylation and different histone marks (H3K4me2, H3K36me2, H3K9ac, H3K9me2 and H3K27me3). Although no significant differences in global 5-methyl deoxicytidine were found, almost a 2-4.5-fold increase in H3K9ac was observed in albino plants in comparison with variegated or green plants, suggesting a change in chromatin compaction related to A. angustifolia albinism.