Plastid Structure and Development in Green Callus Tissues of Oxalis dispar

Cultured callus tissues derived from endosperm of Oxalis disparare shown to contain virescent amyloplasts. In darkness, proplastidsdevelop into typical amyloplasts, starch being deposited assingle or multiple grains. In light, amyloplasts are transformedinto chloroplasts. Thylakoid formation begins in spaces aroundand between existing starch grains. As thylakoids are assembledinto grana, starch slowly disappears; the plastids increasein size and the photosynthetic apparatus enlarges to fill thewhole of the plastid. Slight carotenoid synthesis takes placeas amyloplasts are laid down, but there is no chlorophyll synthesis.All pigments accumulate rapidly during the early stages of granaldevelopment, but slowly, and at a declining rate, during thelater stages. Treatment of the tissues with auxins suppressesthe development of thylakoid membranes, but has no effect uponthe development of amyloplast membranes. The possible significanceof this observation is discussed. Greening is accompanied by a marked decline in the rates ofboth cell division and cell expansion. This is attributed inpart to the diversion of nitrogen from the normal growth channelsinto the synthesis of thylakoid proteins.     

Biosynthesis of chiral 3-hydroxyvalerate from single propionate-unrelated carbon sources in metabolically engineered <Emphasis Type="Italic">E. coli</Emphasis>

Background  

The ability to synthesize chiral building block molecules with high optical purity is of considerable importance to the fine chemical and pharmaceutical industries. Production of one such compound, 3-hydroxyvalerate (3HV), has previously been studied with respect to the in vivo or in vitro enzymatic depolymerization of biologically-derived co-polymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate). However, production of this biopolymeric precursor typically necessitates the supplementation of a secondary carbon source (e.g., propionate) into the culture medium. In addition, previous approaches for producing 3HV have not focused on its enantiopure synthesis, and thus suffer from increased costs for product purification.     

Role of HLA DRB1*15 and HLA DRB1*16alleles in the genetic susceptibility to develop systemic lupus erythematosus (SLE) after Chikungunya and Zika viruses infection in México

Systemic lupus erythematosus (SLE) is a clinically and genetically heterogeneous disease particularly prevalent in Mexico. Althoughits etiology is unknown, genetic factors strongly influence its presenceas well as triggering factors, such as viral infections, including Cytomegalovirus and Epstein-Barr virus. Here,the study presents the appearance of de novoSLE (patients who did not present SLE before de virus infection, corroborated by serological analysis and negative for antinuclear antibodies) cases in Mexicans who live near the southern border of Mexico, who presented clinical symptoms of arthritic, hematological, mucocutaneous and renal SLE, after Zika and/ or Chikungunya virus infection. Low resolution class Ⅱ HLA typing was performed, which found a significantly increased frequency of HLA DRB1*02 (15 and 16)when compared to a group of 99 healthy individuals (P =0.001, OR=4.5, IC95% 1.8~11.0). All the patients were diagnosed with SLE 1 to 3 years after being confirmed with the Zika, and/or Chikungunya infection. At the point of acute viral infection, none of the patients presented clinical signs or symptoms of autoimmunity or were negative for antinuclear antibodies. In genetically susceptible individuals, Zika and Chikungunya viral infection can trigger SLE.     

Preservation of fresh edible cactus stems (<i>Opuntia ficus indica</i> Mill.) by modified atmosphere packaging

Cactus stems, the cladodes of Opuntia spp. cacti, are consumed in Mexico and other countries due to their fresh and herbaceous flavor, and because of their widely known nutraceutical benefits. In order to extend the postharvest life of this vegetable, the effect of a modified atmosphere packaging (MAP) was studied in cactus stems of the cultivar Atlixco stored at 4 ± 1 °C for 20 days under three types of atmospheres: (1) air (passive atmosphere), (2) 5 kPa O₂ + 4 kPa CO₂, and (3) N₂. During storage, the titratable acidity decreased and the color of cladodes became darker and less green; however, the 5 kPa O₂ + 4 kPa CO₂ atmosphere was able to preserve both quality characteristics. All modified atmospheres reduced weight loss (from 8 to <2%) and the symptoms of chilling injury, and this physiological disorder appeared earlier in controls than in MAP-stored cladodes. The levels of fermentation metabolites were low in all three evaluated atmospheres. Because of this, only cladodes stored under the N₂ atmosphere were selected for furthersensory analysis of the MAP effect on odor perception as evaluated by a trained panel. Results indicated that there was no detrimental effect (atypical odors) of MAP on this sensory characteristic. We conclude that cultivar Atlixco is suitable for preservation using MAP technology.     

Relaxin-3 and RXFP3 expression, and steroidogenic actions in the ovary of teleost fish

Relaxins are peptides similar in secondary structure to insulins. In teleost genomes, five or six relaxin genes have been identified. Two relaxins group closely with mammalian relaxin-3 on phylogenetic analysis and are named relaxin-3a and b. We refer to the remainder as relaxins c to f. Ovarian expression of relaxin-3a, d and f genes, and the relaxin-3 receptor gene Rxfp3, was studied in Danio rerio using RT-PCR. Immunohistochemistry was used to determine the distribution of relaxin-3 peptides and RXFP3 in the ovary of Fundulus heteroclitus (killifish). Thirdly, enzyme immunoassays and ovarian follicular culture were used to determine the effect of treatment with human recombinant relaxin-3 on the production of 17beta-estradiol and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one in killifish ovarian follicles. Relaxin-3a, d, f, and Rxfp3 genes were expressed regardless of sex or reproductive condition. Relaxin-3 immunostaining was present in mid to late follicular stages within cortical alveoli of the oocyte cytopasm, whereas receptor staining was localized to follicular cells. Treatment with relaxin-3 enhanced 17beta-estradiol production in early and late maturing follicles, but did not have an effect in vitellogenic follicles. Relaxin-3 appeared to suppress the release of MIS production. This suggests that relaxin peptides may be involved with estradiol-dependant events in follicular development.     

Visualization of elusive structures using intracardiac echocardiography: Insights from electrophysiology

Echocardiography has the ability to noninvasively explore hemodynamic variables during pharmacologic or exercise stress test in patients with heart failure. In this review, we detail some important potential applications of stress echocardiography in patients with heart failure. In patients with coronary artery disease and chronic LV dysfunction, dobutamine stress echocardiography is able to distinguish between viable and fibrotic tissue to make adequate clinical decisions. Exercise testing, in combination with echocardiographic monitoring, is a method of obtaining accurate information in the assessment of functional capacity and prognosis. Functional mitral regurgitation is a common finding in patients with dilated and ischaemic cardiomyopathy and stress echocardiography in the form of exercise or pharmacologic protocols can be useful to evaluate the behaviour of mitral regurgitation. It is clinical useful to search the presence of contractile reserve in non ischemic dilated cardiomyopathy such as to screen or monitor the presence of latent myocardial dysfunction in patients who had exposure to cardiotoxic agents. Moreover, in patients with suspected diastolic heart failure and normal systolic function, exercise echocardiography could be able to demonstrate the existence of such dysfunction and determine that it is sufficient to limit exercise tolerance. Finally, in the aortic stenosis dobutamine echocardiography can distinguish severe from non-severe stenosis in patients with low transvalvular gradients and depressed left ventricular function.