Self-Repair in Cacti Branches: Comparative Analyses of Their Morphology, Anatomy, and Biomechanics.

Damage-repair is particularly important for the maintenance of the water-storing abilities of succulent plants such as cacti. Comparative morphological, anatomical, and biomechanical analyses of self-repair were performed on artificially wounded branches of Opuntia ficus-indica and Cylindropuntia bigelovii. Macroscopic observations, contrast staining, and lignin-proof staining were used to investigate morphological and anatomical responses after wounding at various time intervals. Two-point bending tests were repeatedly performed on the same branches under unwounded, freshly wounded, and healed conditions by using customized 3D-printed clamping jaws. Morphologically, both species showed a rolling-in of the wound edges, but no mucilage discharge. Anatomically, ligno-suberized peridermal layers developed that covered the wound region, and new parenchyma cells formed, especially in O. ficus-indica. In all samples, the wounding effect directly after damage caused a decrease between 18% and 37% in all the tested mechanical parameters, whereas a positive healing effect after 21 days was only found for C. bigelovii. Based on our data, we hypothesize a high selection pressure on the restoration of structural integrity in the wound area, with a focus on the development of efficient water-retaining mechanisms, whereas the concept of "sufficient is good enough" seems to apply for the restoration of the mechanical properties.

Not all the infected develop the disease - A "Lotus and Cactus" model.

The immunogenetic dictum "not all the infected develop the disease" can best be explained by a "Lotus and Cactus" model. Lotuses grow in ponds and cacti in deserts: analogously, we can say that tubercle patient's lung (genetic makeup) functions as an ideal 'broth' for Mycobacterium tuberculosis (M.tb) germs to grow, but not the lungs of an endemic control. HLA association studies from Europe to Asia since 1983 till date, have shown a persistent HLA DR2 (15) association. Further, HLA DR2 and non-DR2 endemic controls showed disparate patterns of immune responses and gene expressions. The host and pathogen MHC diversities, Th1-Th2 paradigm and cytokine circuits all may play a crucial role in TB susceptibility. It is possible to decipher the protective immunity by controlling the known confounders - epidemiological, demographic, socio-biological and also host and pathogen diversities. This has become significant with our understanding on the 'out of Africa' migration and neolithic co-dispersal of M.tb with modern human. Divergence and expansion of various MHCs (eg HLA-DRB1*15, HLA-B*57) and non-MHC alleles in various continents might be responsible for the skewed transmission and distribution of the infectious diseases around the globe. The 'Lotus and Cactus' model proposed here exemplifies this. A holistic genetic epidemiology approach employing modern tools is the need of the hour to better understand infectious disease susceptibility.

Primer reporte del empleo de marcadores ISTR en cactaceae (pilosocereus sp) / First report of the employment of ISTR markers in cactaceae (pilosocereus sp)

Pilosocereus sp es una especie en peligro crítico de extinción, la única población conocida se encuentra en una mina de mármol verde, hoy abandonada, en la que su explotación produjo la disminución del 80% de la población en 3 años; en la actualidad quedan 28 ejemplares, de ellos unos pocos son adultos, de los cuales solo dos producen frutos. Una de las etapas necesaria para su recuperación es la producción de plántulas para realizar el reforzamiento de la población natural. Como las plantas obtenidas serán plantadas en condiciones naturales, donde se enfrentarán a diversas situaciones ambientales, es conveniente realizar un estudio de diversidad genética. El objetivo de este trabajo fue estimar la variabilidad genética de plántulas de Pilosocereus sp empleando la técnica Inverse Sequence Tagged Repeat (ISTR). Se realizó la germinación in vitro de semillas y se determinó la variabilidad genética de las plántulas obtenidas. Con el análisis molecular se detectaron un total de 97 bandas, de ellas el 62,8% fueron polimórficas. El mayor porcentaje de bandas polimórficas (85,7%) se obtuvo con la combinación de oligonucleótidos F6/B6. Con las combinaciones de oligonucleótidos empleados se detectaron de 4 a 6 patrones de banda diferentes. La heterocigosidad media esperada fue de 0,39.

Pilosocereus sp is a species in critical extinction danger, the only known population is in a mine of green marble, abandoned today, but it exploitation produced the decrease of the population's 80% in 3 years, at the present time they are 28 individuals, of them some few ones are mature, of those which alone two produce fruits. One of the necessary stages for their recovery is the seedlings production to carry out the natural population's reinforcement. As the obtained plants they will be planted under natural conditions, where they will face diverse environmental situations, it is convenient to carry out a study of genetic diversity. The objective of this work was to estimate the genetic variability using the technical Inverse Sequence Tagged Repeat (ISTR). In vitro germination of seeds of Pilosocereus sp and the genetic variability of the obtained seedlings was determined. With the molecular analysis a total of 97 bands were detected, of them 62.8% were polymorphic. The biggest percentage of polymorphism (85.7%) was obtained with the primer combination F6/B6. With the primer combinations employed were detected from 4 to 6 different band patterns. The heterocigocity hoped was 0.39.

Rash after visiting Tucson.

Cactus dermatitis is a common problem among harvesters of cactus fruit. The smaller spines (glochidia) are responsible for most of the dermatitis. Easily separated from the body of the plant, the glochidia may be transferred to bystanders through contact with clothing or pets exposed to these cacti. Removal of the glochidia from the skin is key to treatment, and household glue may aid in this extraction.