Biology

To guarantee seeds with high physiological quality performing in a uniform, resilient and tolerant to abiotic stress plant stand, procedures that can improve the potential of the processed seed. Biostimulants are considered promising alternatives, both to improve the physiological performance of plants and in resilience and stress tolerance. The objective of this study was to verify the effect of coatingseeds of different cultivars of carrots with biostimulant based on algae Solieria filiformison seed germination and seedling development under thermal stress. The experiment was conducted in a completely randomized design, with a 3 x 4 factorial scheme (temperaturesand doses), with five replications. Carrot seeds from the cultivars Brasília, Danvers, Esplanada and Planalto were used, and the seeds were coated with doses of 0, 2, 4 and 8 mL.L-1 of biostimulant. After covering, the seeds were submitted to the following: percentage and speed of germination, length of seedlings and dry m...

Organic agriculture has been growing in recent years; however, one of the limitations in this area is the treatment of seeds with natural products and less aggressive to the environment. Seed biopriming with brown seaweed extract can be used to improve the physiological quality of seeds. This study aimed to evaluate the effect of seed biopriming with Ascophyllum nodosum extracts (algae) on pepper and tomato seed quality. Pepper seeds of All Big and Alegria cultivars (cvs), and tomato seeds of Cereja and Rio Grande cvs were used. The extract concentrations were 0, 125, 250, and 375 ppm. A completely randomized design in a 2×4 factorial scheme was used. The variables analyzed were percentage germination; germination speed index; root and shoot length; and root and shoot dry weight. Sweet pepper biopriming at 125 ppm enhanced germination in 16.5% for All Big cv; but it did not benefit Alegria cv. A. nodosum as a biopriming provided an increase of 50% in root length growth in Alegria cv...

A alface é uma hortaliça de grande produção e consumo e propagada via sementes. A presente pesquisa visou avaliar a influência no tratamento de sementes de alface de diferentes cultivares de bioestimulantes à base de algas, na germinação e no desenvolvimento de plântulas. Foram utilizados bioestimulantes das algas Ascophyllum nodosum e Solieria spp. O delineamento experimental usado foi inteiramente casualizado, em esquema fatorial 3 × 4 (cultivares e doses), separadamente, para cada bioestimulante, com cinco repetições. Utilizaram-se as cultivares de alface Batavia Cacimba, Grand Rapids e Itapuã Super, e as doses de 0, 1, 2 e 4 mL.L-1. O desempenho das sementes foi avaliado por meio de: teste de germinação, índice de velocidade de germinação, comprimento de raízes e de parte aérea e massa seca de plântulas. Os dados obtidos foram submetidos a análise de variância, teste de Tukey, para comparação de cultivares (p < 0,05), e análise de regressão, para avaliação do fator doses. As ...

Seed priming is a treatment that can contribute to improve seed physiological potential and increase its tolerance to abiotic stresses. Thus, this work evaluated the effect of kale seed priming with red seaweed biostimulant on physiological seed potential, seed health and tolerance to high temperature at germination. The experimental design was completely randomised, with a 2´x4 factorial scheme. Treatments consisted of doses of 0, 0.25, 0.50 and 1.0 mL L–1 of red algae Solieria sp. biostimulant, and temperatures of 20 and 30°C. The biostimulant used was subjected to chromatographic analysis to detect bioactive compounds. Seed imbibition curves were used to determine priming duration procedure. Treatments effects were evaluated by seed health, germination, root and shoot length, and dry mass, under ideal (20°C) and stress (30°C) temperatures. The results were submitted to analysis of variance, Tukey’s test (temperatures) and regression (doses). The 22-h imbibition period is adequate...

Seed priming is a technique used to induce metabolic germination processes. Use of growth regulators in seed priming may facilitate increments in physiological processes during seed germination. The objective of this study was to evaluate the effect of priming and growth regulators on beet seed germination. The treatments were cultivar type (Early Wonder, Itapuã and Maravilha) and seed priming technique, which included a control (unconditioned seed) standard hydropriming (water) and a conditioning with salicylic, gibberellic and ascorbic acids, respectively. The treatments were defined by initially testing 0, 1, 2 and 4 mM ascorbic, gibberellic and salicylic acids. Before seed priming, imbibition seed curves were established to determine the optimal conditioning time. After conditioning, the germination, rate of germination, seedling length and seedling dry weight were evaluated. First, the appropriate dosage for conditioning was determined by using a completely randomized experimen...

Nowadays, image analysis is one of the most modern tools in evaluating physiological potential of seeds. This study aimed at verifying the efficiency of the seedling imaging analysis to assess physiological potential of wheat seeds. The seeds of wheat, cultivars IAC 370 and IAC 380, each of which represented by five different lots, were stored during four months under natural environmental conditions of temperature (T) and relative humidity (RH), in municipality of Piracicaba, Stated of São Paulo, Brazil. For this, bimonthly assessments were performed to quantify moisture content and physiological potential of seeds by means of tests of: germination, first count, accelerated aging, electrical conductivity, seedling emergence, and computerized analysis of seedlings, using the Seed Vigor Imaging System (SVIS®). It has been concluded that the computerized analyses of seedling through growth indexes and vigor, using the SVIS®, is efficient to assess physiological potential of wheat seeds.

The use of high quality seeds is one of the important factors to increase productivity in areas cultivated with sunflower. The aim of this study was to investigate the relationship between internal morphology and germination of sunflower seeds with the X-ray test and computer-aided X-ray imaging analysis with the software Tomato Analyzer®, and check whether or not this relationship changes after a period of seed storage under different environmental conditions. For this purpose, five lots of sunflower seeds from cultivar Catissol 01 were used. They were evaluated during two experimental periods: at 0 and 4 months after storage; the first evaluation was performed to characterize the lots; after that, the seeds were stored in two environments, cold and dry chamber (10 °C and 30% relative air humidity) and non-controlled environment. The seed moisture content was determined and, after that, the seeds were submitted to the X-ray and germination tests. The X-ray analysis allowed the visu...

Structural differences such as abnormalities, damage and free spaces in seeds may affect germination. The aim of this study was to study the relationship between eggplant seed morphology and seed germination. Ten seed lots of the eggplant cultivar Embu were evaluated by X-ray image analysis and the germination test. Seed image analysis was performed by Image Pro Plus® software and the whole seed area and free space between the embryo and endosperm were measured. The internal seed area filled by the embryo and endosperm was calculated from the difference between the whole seed and free space areas. Based on these results and visual seed analysis, seeds were classified into three categories and information on germination was obtained for each one. X-ray image analysis provides a perfect view of the internal seed parts and for seed morphology studies. An increase in seed area filled by the endosperm and embryo does not improve seed germination. Mechanical seed damage and deteriorated t...

Significance Our results provide an example of reactivation of a signaling pathway important in embryogenesis that can be exploited to promote tissue repair and help host recovery from bacterial pneumonia. Although this approach of regenerative medicine will not curtail infection per se, it reduces suffering and shortens recovery time by fostering tissue repair, thus complementing antibiotic treatment and improving patient outcomes from serious infections. Our findings open up a frontier in the treatment of microbial infections using microRNA-based regenerative therapy.

A multibranched hierarchy of regulatory genes controls all aspects of somatic sexual development in Drosophila melanogaster. One branch of this hierarchy is headed by the fruitless (fru) gene and functions in the central nervous system, where it is necessary for male courtship behavior as well as the differentiation of a male-specific abdominal structure, the muscle of Lawrence (MOL). A preliminary investigation of several of the mutations described here showed that the fru gene also has a sex-nonspecific vital function. The fru gene produces a complex set of transcripts through the use of four promoters and alternative splicing. Only the primary transcripts produced from the most distal (P1) promoter are sex-specifically spliced under direction of the sex-determination hierarchy. We have analyzed eight new fru mutations, created by X-ray mutagenesis and P-element excision, to try to gain insight into the relationship of specific transcript classes to specific fru functions. Males t...

Betaglycan, also known as the TGF-beta type III receptor, is a membrane-anchored proteoglycan that presents TGF-beta to the type II signaling receptor, a transmembrane serine/threonine kinase. The betaglycan extracellular region, which can be shed by cells into the medium, contains a NH2-terminal domain related to endoglin and a COOH-terminal domain related to uromodulin, sperm receptors Zp2 and 3, and pancreatic secretory granule GP-2 protein. We identified residues Ser535 and Ser546 in the uromodulin-related region as the glycosaminoglycan (GAG) attachment sites. Their mutation to alanine prevents GAG attachment but does not interfere with betaglycan stability or ability to bind and present TGF-beta to receptor II. Using a panel of deletion mutants, we found that TGF-beta binds to the NH2-terminal endoglin-related region of betaglycan. The remainder of the extracellular domain and the cytoplasmic domain are not required for presentation of TGF-beta to receptor II; however, membran...

Acetyl-CoA carboxylase I (ACCI) is a key lipogenic enzyme whose induction in islet β-cells may contribute to glucolipotoxicity. Here, we provide evidence that enhanced insulin release plays an important role in the activation of this gene by glucose. Glucose (30 vs. 3 mmol/l) increased ACCI mRNA levels ∼4-fold and stimulated ACCI (pII) promoter activity >30-fold in MIN6 cells. The latter effect was completely suppressed by blockade of insulin release or of insulin receptor signaling. However, added insulin substantially, but not completely, mimicked the effects of glucose, suggesting that intracellular metabolites of glucose may also contribute to transcriptional stimulation. Mutational analysis of the ACCI promoter, and antibody microinjection, revealed that the effect of glucose required sterol response element binding protein (SREBP)-1c. Moreover, adenoviral transduction with dominant-negative-acting SREBP1c blocked ACCI gene induction, whereas constitutively active SREBP1c in...

Kidney glomerulosclerosis commonly progresses to end-stage kidney failure, but pathogenic mechanisms are still poorly understood. Here, we show that podocyte expression of decay-accelerating factor (DAF/CD55), a complement C3 convertase regulator, crucially controls disease in murine models of adriamycin (ADR)-induced focal and segmental glomerulosclerosis (FSGS) and streptozotocin (STZ)-induced diabetic glomerulosclerosis. ADR induces enzymatic cleavage of DAF from podocyte surfaces, leading to complement activation. C3 deficiency or prevention of C3a receptor (C3aR) signaling abrogates disease despite DAF deficiency, confirming complement dependence. Mechanistic studies show that C3a/C3aR ligations on podocytes initiate an autocrine IL-1β/IL-1R1 signaling loop that reduces nephrin expression, causing actin cytoskeleton rearrangement. Uncoupling IL-1β/IL-1R1 signaling prevents disease, providing a causal link. Glomeruli of patients with FSGS lack DAF and stain positive for C3d, and...

The African citrus psyllid Trioza erytreae is one of the major threats to citrus industry as the vector of the incurable disease known as huanglongbing (HLB) or citrus greening. The psyllid invaded the northwest of the Iberian Peninsula 6 years ago. The invasion alarmed citrus growers in the Mediterranean basin, the largest citrus producing area in Europe, which is still free of HLB. Before our study, no research had been carried out on the genetic diversity of T. erytreae populations that have invaded the Iberian Peninsula and the archipelagos of the Macaronesia (Madeira and the Canary Islands). In this study, combining microsatellites markers and mtDNA barcoding analysis, we characterize the genetic diversity, structure and maternal relationship of these new invasive populations of T. erytreae and those from Africa. Our results suggest that the outbreaks of T. erytreae in the Iberian Peninsula may have derived from the Canary Islands. The populations of T. erytreae that invaded Ma...