Dent and Flint maize diversity panels reveal important genetic potential for increasing biomass production

Key message

Genetic and phenotypic analysis of two complementary maize panels revealed an important variation for biomass yield. Flowering and biomass QTL were discovered by association mapping in both panels.

Abstract

The high whole plant biomass productivity of maize makes it a potential source of energy in animal feeding and biofuel production. The variability and the genetic determinism of traits related to biomass are poorly known. We analyzed two highly diverse panels of Dent and Flint lines representing complementary heterotic groups for Northern Europe. They were genotyped with the 50 k SNP-array and phenotyped as hybrids (crossed to a tester of the complementary pool) in a western European field trial network for traits related to flowering time, plant height, and biomass. The molecular information revealed to be a powerful tool for discovering different levels of structure and relatedness in both panels. This study revealed important variation and potential genetic progress for biomass production, even at constant precocity. Association mapping was run by combining genotypes and phenotypes in a mixed model with a random polygenic effect. This permitted the detection of significant associations, confirming height and flowering time quantitative trait loci (QTL) found in literature. Biomass yield QTL were detected in both panels but were unstable across the environments. Alternative kinship estimator only based on markers unlinked to the tested SNP increased the number of significant associations by around 40 % with a satisfying control of the false positive rate. This study gave insights into the variability and the genetic architectures of biomass-related traits in Flint and Dent lines and suggests important potential of these two pools for breeding high biomass yielding hybrid varieties.     

5-Alkylated thiazolidinones as follicle-stimulating hormone (FSH) receptor agonists

We prepared analogs of potent thiazolidinone-based follicle-stimulating hormone (FSH) agonists 1, that is, 3 that contained an additional 5-alkyl substituent. This extra substituent was added to reduce synthetic problems that arose during preparation of analogs of 1. These compounds (3) were evaluated in a Chinese hamster ovary (CHO) cell line that expressed recombinant human FSH receptor (FSHR) and a luciferase reporter gene regulated by a cAMP response element (CRE). Selected compounds were also tested on a CHO-cell line that over expressed the FSHR for the ability to induce cAMP production. When the 5-alkyl substituent was a methyl group as in analog 16a, similar FSH activity (i.e., EC(50) = 51 nM, 100% efficacy relative to hFSH) to the analogous 5-hydrogen series compound (e.g., 2) was observed; thus, proving that a small 5-alkyl substituent was well tolerated. New derivatives of 3, in which the potentially hydrolytically labile secondary amide function of 1 (-CONH-) was modified to other moieties (e.g., -CH(2)NH-, -CH(2)S-, and -CH(2)OCONH-), were also prepared and evaluated. These congeners (namely 21, 22, and 24) also displayed good potency in the CRE-luciferase assay.     

Indole- and benzothiophene-based histamine H3 antagonists

Previous research on histamine H₃ antagonists has led to the development of a pharmacophore model consisting of a central phenyl core flanked by two alkylamine groups. Recent investigation of the replacement of the central phenyl core with heteroaromatic fragments resulted in the preparation of novel 3,5-, 3,6- and 3,7-substituted indole and 3,5-substituted benzothiophene analogs that demonstrate good to excellent hH₃ affinities. Select analogs were profiled in a rat pharmacokinetic model.     

Antimicrobial activity of silymarin mediated zinc oxide and hydroxy apatite nanoparticles against oral pathogens

The nanoparticles such as hydroxyapatite, zinc oxide, titanium dioxide and zirconium nanoparticles have application in dentistry. Therefore, it is of interest to document the antimicrobial activity of silymarin mediated zinc oxide and hydroxy apatite nanoparticles against oral pathogens. Hence, we synthesized hydroxyapatie and zinc oxide nanoparticles with silymarin and characterized by UV-visible spectrophotometer. Data shows that silymarin mediated HAP and ZnO nanoparticles have antimicrobial activity against oral pathogens such as Pseudomonas sp, Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans.     

A new Sphagesaurus (Mesoeucrocodylia: Notosuchia) from the Upper Cretaceous of Monte Alto City (Bauru Group,Brazil), and a revision of the Sphagesauridae

Oxygen consumption and ammonia excretion rates were assessed for Terebratulina retusa (L.) held under 3 different regimes of temperature and food availability. These were: 5.6?C, no food (cold, starved); 5.8?C, food present (cold, fed) and 10.7?C food present (warm, fed), which simulated winter conditions, summer conditions and an intermediate treatment. Regressions of oxygen consumption on ash‐free dry weight (AFDW) had slopes which were not significantly different from each other and ranged from 0.953 to 0.999. A common slope of 0.976 was calculated and intercepts based on the common slope used to compare oxygen consumption in each treatment. The rise from cold, starved conditions to warm, fed was 24.5 per cent and this was significant (P < 0.05). Other differences were not significant (P > 0.05) but the cold, fed result was 12.6 per cent higher than cold, starved. Therefore feeding and temperature probably account for equivalent proportions of the rise in metabolism from winter to summer. Ammonia production data were much more variable. Excretion rates of a 50 mg AFDW individual (in ng‐at NH₃‐N.h^‐1) were as follows: cold, starved: 30.2 cold, fed: 7.1; and warm, fed: 22.9. Oxygen to nitrogen (O:N) ratios reflected these results. Mean O:N ratios were: cold, starved: 8.0; cold, fed: 42.4; warm, fed: 16.3. This shows that the simulated winter group relied heavily on protein to fuel their metabolism, the simulated summer group were less dependent on protein and the intermediate group probably used lipids and carbohydrates to fuel metabolic demands. This possibly reflected a trade off between food supply and increased metabolism from treatment to treatment, demonstrating a flexibility which could have been a contributing factor in the ecological tolerance and geological longevity of some brachiopods.     

Evaluation of management treatments intended to increase lamb recruitment in a bighorn sheep herd

We administered a suite of treatments to a herd of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) that was experiencing poor lamb recruitment and showing signs of respiratory disease. Despite 3 yr of treatment with various combinations of anthelmentics, antibiotics, vaccines, and hyperimmune serum products, recruitment was not improved.     

The Diversity of Flower Flies (Diptera: Syrphidae) in Colombia and Their Neotropical Distribution

In Colombia, like most Neotropical countries, faunistic studies on flower flies have been occasional and most of them have been primarily focused on taxonomy. Colombia is the second-most species-rich country in flower fly diversity in the Neotropics after Brazil, and has one of the highest numbers of species per unit area (2.49 per 10,000?km²), based on a review of literature and national collections. Including new data presented here, a total of 47 genera and 300 species are recorded in Colombia. The genera Scaeva Fabricius and Lycastrirhyncha Bigot, as well as 101 species are recorded here for the first time. The altitudinal range and the distribution of the flower fly genera in Colombia are presented. A preliminary comparison of the fauna of Colombia with that of other Neotropical countries is given. A historical perspective is also provided in order to illustrate how Colombian Syrphidae knowledge has progressed over the last 168?years. Information presented here will be useful for ongoing and future biodiversity research as well as conservation projects on Syrphidae in the Neotropical region.     

Role of DegP for two-partner secretion in Bordetella

Sorting of proteins destined to the surface or the extracellular milieu is mediated by specific machineries, which guide the protein substrates towards the proper route of secretion and determine the compartment in which folding occurs. In Gram-negative bacteria, the two-partner secretion (TPS) pathway is dedicated to the secretion of large proteins rich in β-helical structure. The secretion of the filamentous haemagglutinin (FHA), a 230 kDa adhesin of Bordetella pertussis , represents a model TPS system. FHA is exported by the Sec machinery and transits through the periplasm in an extended conformation. From there it is translocated across the outer membrane by its dedicated transporter FhaC to finally fold into a long β-helix at the cell surface in a progressive manner. In this work, we show that B. pertussis lacking the periplasmic chaperone/protease DegP has a strong growth defect at 37°C, and the integrity of its outer membrane is compromised. While both phenotypes are significantly aggravated by the presence of FHA, the chaperone activity of DegP markedly alleviates the periplasmic stress. In vitro , DegP binds to non-native FHA with high affinity. We propose that DegP chaperones the extended FHA polypeptide in the periplasm and is thus involved in the TPS pathway.