Protocol for the Acclimatization of Coconut Vitro-Plants Under Ex Vitro Conditions.

The coconut tree is a crop widely distributed in more than 90 countries worldwide. It has a high economic value derived from the large number of products obtained from the plant, with fast-growing global markets for some of them. Unfortunately, coconut production is decreasing mainly due to the old age of the plants and devastating pests and diseases, such as phytoplasma disease lethal yellowing (LY). Massive replanting is required with phytoplasma-resistant and high-yielding selected coconut plants to keep up with the market demand for fruit. For this purpose, an efficient micropropagation technology via somatic embryogenesis has been established at CICY, yielding fully developed vitro-plants grown within an in vitro environment. Hence, the last stage of the micropropagation process is the acclimatization of the vitro-plants, which are gradually adapted to live in external conditions outside the glass container and the growth room. A protocol has been developed at CICY to acclimate the coconut vitro-plants, and close to 80% survival can be obtained. This protocol is described here.

In vitro transmission of 16SrIV phytoplasmas to coconut plants by Haplaxius crudus in Yucatan, Mexico.

The coconut palm is an important crop worldwide. In America, it is affected by lethal yellowing (LY) disease, associated with the presence of 16SrIV ribosomal group phytoplasmas. Studies in Florida using insect-proof cages indicate Haplaxius crudus as a vector of LY phytoplasmas to palm species, including coconut. Here, an in vitro transmission system was used to verify that H. crudus collected in Yucatan, Mexico, transmit 16SrIV phytoplasmas to coconut. Three transmission trials were carried out using micropropagated coconut plants. In each trial, at least one plant was positive to 16SrIV phytoplasmas. In total, there were 4 positive plants out of 34 exposed to insects, and the phytoplasma presence was detected in root, stem, and leaf tissues. The phytoplasmas identified were 16SrIV-A and 16SrIV-D, both found in both plants and insects. In each assay where a plant was positive for either 16SrIV-A or 16SrIV-D, the same phytoplasma was present in the insect or insects used in this assay. This is the first demonstration of transmission of LY phytoplasmas to coconut plants by H. crudus in Mexico and with an in vitro system. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-03069-z.

A peak in global DNA methylation is a key step to initiate the somatic embryogenesis of coconut palm (Cocos nucifera L).

KEY MESSAGE: DNA methylation, morphogenesis and gene expression during the somatic embryogenesis of Coconut are affected by 5-Azacytidine pretreatments, indicating that DNA methylation is an important factor throughout this process. Somatic embryogenesis (SE) is a process that can aid in the production of elite Cocos nucifera palms. It has been well established that epigenetic mechanisms are regulators of cell differentiation programs; however, their role in the coconut somatic embryogenesis has not yet been addressed. To this end, the morphogenetic changes, the global DNA methylation and the expression profiles of the SE-related genes and DNA methyltransferases genes were evaluated during the SE process, with and without the presence of 5-Azacytidine (AzaC). The results show that three days of pretreatments with 15 µM and 20 µM of AzaC significantly increased early somatic embryo formation (four- and tenfold, respectively). A clear peak of the global percentage of DNA methylation (approximately 13%) was determined at the beginning of the culture, followed by a re-establishing stage and a steady increase thereafter; in all cases, the levels of DNA methylation were lower after the pretreatments with AzaC. Additionally, the expression profiles of the SERK, WUS, BBM and LEC genes are modulated during the SE process and the pretreatments with AzaC affect the expression profiles of these genes, even at early stages. Furthermore, increased levels of expression were observed for the genes encoding for DNA methyltransferases (MET, CMT and DRM) at early and late stages of SE, indicating that DNA methylation is an important factor throughout the SE.

Addition of ionophore A23187 increases the efficiency of Cocos nucifera somatic embryogenesis.

The present study reports the effect of treatment of coconut embryogenic structure explants (derived from embryogenic callus) with the calcium ionophore A23187 (0, 1, 5, 10 µM) to promote somatic embryogenesis under in vitro conditions. The results showed no significant increase in the percentage of explants forming embryogenic callus, but with 1 µM ionophore there were significant increases in the formation of embryogenic structures per callus (2.8-fold), of somatic embryos per callus (1.5-fold) and also a greater absolute number (1.5-fold) of developing plantlets per callus. The ionophore treatment also promoted a change of pattern of the expression of the CnSERK gene during embryogenic callus formation. It is proposed that if the use of ionophore A23187 treatment is coupled with an embryogenic callus multiplication process there could be a potentially greater increase in the efficiency of the formation of somatic embryos and plantlets of coconut.

Protocol for the Micropropagation of Coconut from Plumule Explants.

Coconut is a crop that is economically important in several countries throughout the world. Unfortunately, production is decreasing because palms are affected by very serious phytoplasma diseases, such as lethal yellowing, and also most of coconuts are already very old. On the other hand, markets for coconut products have been rapidly growing in recent years. Hence, replanting of most cultivation surface worldwide, as well as establishing new surface, is urgently needed. This is an immense task, requiring at least a billion coconut palms that cannot be accomplished by traditional propagation through seed. Therefore the biotechnological alternative of micropropagation by somatic embryogenesis is needed. Research has been carried out on this subject in laboratories in several countries studying different approaches, testing different types of explants. The most responsive tissue has been plumule from zygotic embryos. A protocol for micropropagation of coconut based on plumule explants is described here. It involves the use of different media that are based on Y3 medium complemented with activated charcoal, gelling agent, sucrose, and growth regulators. These media allow the formation of embryogenic callus and somatic embryos, growth of shoots, and development of plantlets.

Presence of 16SrIV phytoplasmas of subgroups A, D and E in planthopper Haplaxius crudus Van Duzee insects in Yucatán, Mexico.

The present study was carried out to determine if group 16SrIV phytoplasmas, causing lethal yellowing (LY) disease, are present in Haplaxius crudus Van Duzee (Hemiptera: Cixiidae) insects associated with palms in Yucatán, Mexico. Haplaxius crudus feral insects were captured from palm foliage at two locations (Chicxulub Puerto and CICY, Mérida, where LY-type diseases are active) and evaluated individually for the presence of phytoplasma DNA by a group 16SrIV-specific nested PCR assay. The results showed positive detection in H. crudus insects in a proportion of 2.7% (of the total 2726 analyzed) during a 3-year period of study. The percentage of detection was different for each site, 5.9% positive of 799 insects from Mérida and 1.7% of 1927 from Chicxulub Puerto. Positive detections were also obtained in extracts from 5.3 to 1.2% of males and females, respectively. Sequencing and in silico RFLP and phylogenetic analyses of PCR-amplified rDNA products indicated that H. crudus insects from Chicxulub Puerto harbored phytoplasma strains of subgroups 16SrIV-A or 16SrIV-D, whereas in insects from Mérida the strains found were 16SrIV-A, 16SrIV-D or 16SrIV-E. The diversity of subgroup strains detected in H. crudus coincided with strains previously identified in palms showing LY-type disease syndromes in Yucatán thereby implicating H. crudus as a candidate vector of 16SrIV phytoplasmas in this region of Mexico.

'Candidatus Phytoplasma palmicola', associated with a lethal yellowing-type disease of coconut (Cocos nucifera L.) in Mozambique.

In this study, the taxonomic position and group classification of the phytoplasma associated with a lethal yellowing-type disease (LYD) of coconut (Cocos nucifera L.) in Mozambique were addressed. Pairwise similarity values based on alignment of nearly full-length 16S rRNA gene sequences (1530 bp) revealed that the Mozambique coconut phytoplasma (LYDM) shared 100% identity with a comparable sequence derived from a phytoplasma strain (LDN) responsible for Awka wilt disease of coconut in Nigeria, and shared 99.0-99.6% identity with 16S rRNA gene sequences from strains associated with Cape St Paul wilt (CSPW) disease of coconut in Ghana and Côte d'Ivoire. Similarity scores further determined that the 16S rRNA gene of the LYDM phytoplasma shared <97.5% sequence identity with all previously described members of 'Candidatus Phytoplasma'. The presence of unique regions in the 16S rRNA gene sequence distinguished the LYDM phytoplasma from all currently described members of 'Candidatus Phytoplasma', justifying its recognition as the reference strain of a novel taxon, 'Candidatus Phytoplasma palmicola'. Virtual RFLP profiles of the F2n/R2 portion (1251 bp) of the 16S rRNA gene and pattern similarity coefficients delineated coconut LYDM phytoplasma strains from Mozambique as novel members of established group 16SrXXII, subgroup A (16SrXXII-A). Similarity coefficients of 0.97 were obtained for comparisons between subgroup 16SrXXII-A strains and CSPW phytoplasmas from Ghana and Côte d'Ivoire. On this basis, the CSPW phytoplasma strains were designated members of a novel subgroup, 16SrXXII-B.

Occurrence of a 16SrIV Group Phytoplasma not Previously Associated with Palm Species in Yucatan, Mexico.

The occurrence of 16SrIV group phytoplasmas in palm species Sabal mexicana and Pseudophoenix sargentii is reported here for the first time. Palm trees showed leaf decay and leaf yellowing syndromes, respectively. An amplification product (1.4 kb) was obtained in symptomatic S. mexicana (18 of 21) and symptomatic P. sargentii (1 of 1) palm trees sampled in different locations in Yucatan State, Mexico; five of the positive S. mexicana and the positive P. sargentii trees died. The identity of the phytoplasmas from these species was determined by restriction fragment length polymorphism profiling with restriction enzymes AluI and HinfI, showing there could be two phytoplasma strains of the 16SrIV group. In one S. mexicana palm, the profile was the same as observed with these enzymes for phytoplasmas of 16SrIV-A subgroup, previously associated with Cocos nucifera palm trees and, in the rest of the trees, including the P. sargentii palm, the profile was for phytoplasmas of the 16SrIV-D subgroup. These identities were supported by analyses of the amplicons obtained by nested polymerase chain reaction by nucleotide-nucleotide BLAST analysis. Geographical distribution of the association S. mexicana/16SrIV group phytoplasmas was found widely dispersed in Yucatan State. A potential role of S. mexicana palm trees as a permanent source of phytoplasma inoculum is suggested. In addition to P. sargentii, other palm species (Thrinax radiata and C. nucifera) coexisting with S. mexicana trees were also sampled and analyzed.

In situ PCR detection of phytoplasma DNA in embryos from coconut palms with lethal yellowing disease.

SUMMARY DNA of the lethal yellowing (LY) phytoplasma was detected in 13 of 72 embryos from fruits of four diseased Atlantic tall coconut palms by polymerase chain reaction (PCR) assays employing phytoplasma universal rRNA primer pair P1/P7, nested LY group-specific rRNA primer pair 503f/LY16Sr or LY phytoplasma-specific nonribosomal primer pair LYF1/R1. Phytoplasma distribution in sectioned tissues from six PCR positive embryos was determined by in situ PCR and digoxigenin-11-deoxy-UTP (Dig) labelling of amplification products. Dig-labeled DNA products detected by colourimetric assay were clearly evident on sections from the same three embryos investigated in detail by in situ PCRs employing primer pairs P1/P7 or LYF1/R1. Deposition of blue-green stain on sections as a result of each assay was restricted to areas of the embryos corresponding to the plumule and cells ensheathing it. By comparison, similarly treated embryo sections derived from fruits of a symptomless Atlantic tall coconut palm were consistently devoid of any stain. Presence of phytoplasma DNA in embryo tissues suggests the possible potential for seed transmission which remains to be demonstrated.

Propuesta para la implementaciòn del subsistema nacional de información hospitalario: Hospitales generales, especializados y distritales

En el documento se describe el desarrollo del subsistema de información hospitalario dentro del marco general del Subsistema de Información Nacional en Salud - SNIS. Los criterios rectores de la oficina sectorial de planificación y el apoyo técnico, operativo y financiero del Programa Integrado de Servicios de Salud - PROISS, han sido fortalecidos y ampliamente respaldados en la gestión ministerial, tanto en aspectos de orden financiero y estructural, como administrativo. Este modelo experimentado en el hospital de Clínicas de La Paz, será difundido al resto de los hospitales generales del país ...

Propuesta teórica, metodológica y operativa del proceso de educación permanente de los distritos / sss

El presente documento, la Educación Permanente, concebida como un proceso para cualificar al personal de salud y coadyuvar a elevar el nivel de salud de la población, debe ser considerada como un componente fundamental del proceso de desarrollo de los servicios de salud

Estenosis péptica del esófago: resultados de un procedimiento terapéutico prospectivo / Peptic stenosis of the esophagus: results of the prospective therapeutic procedure

Se hace un análisis de la fisiopatología de la esofagitis por reflujo patológico, con sus distintos grados de lesión hasta llegar a la estenosis fibrosa establecida, que debe diferenciarse de los estados de edema, espasmo y fibrosis inicial de la unión esofagogástrica. Se revisan los distintos tratamientos hasta la fecha en la literatura para el tratamiento del problema y propuestos por su gran complejidad. Se reportan los resultados obtenidos con un protocolo propuesto por los autores, que se utilizó en forma prospectiva en 29 casos de estenosis fibrosa, entre 172 pacientes operados por reflujo patológico. El protocolo comprendió estudio radiológico, endoscópico e histológico, con cirugía antirreflujo por el procedimiento de funduplastia posterior a 270§, seguido en el postoperatorio, de dilataciones guiadas con sondas de Tucker a través de gastrostomía, hasta por 3 meses. Los resultados fueron satisfactorios con dilataciones en 22 casos (81.5%), teniendo que reoperarse 5 casos para sustitución del esófago o resolver la estenosis directamente. Hubo un fallecimiento por neumonía después de una reintervención.

Bases para una política de recursos humanos del sector salud y la implantación del subsistema de información (propuesta) / sss

El objetivo general es el de realizar un diagnóstico cualitativo y cuantitativo de los recursos humanos en salud en los diferentes subsectores (MPSSP, Cajas de Salud, ONGs, Iglesia, Privados, etc), de acuerdo al modelo sanitario, cuyos resultados contribuirán a implementar un subsistema de Información en Recursos Humanos y a delinear las bases para definir la política de Recursos Humanos en el sector