Soilless Plant Growth Media Influence the Efficacy of Phytohormones and Phytohormone Inhibitors

Plant growth regulators, such as hormones and their respective biosynthesis inhibitors, are effective tools to elucidate the physiological function of phytohormones in plants. A problem of chemical treatments, however, is the potential for interaction of the active compound with the growth media substrate. We studied the interaction and efficacy of propiconazole, a potent and specific inhibitor of brassinosteroid biosynthesis, with common soilless greenhouse growth media for rice, sorghum, and maize. Many of the tested growth media interacted with propiconazole reducing its efficacy up to a hundred fold. To determine the molecular interaction of inhibitors with media substrates, Fourier Transform Infrared Spectroscopy and sorption isotherm analysis was applied. While mica clay substrates absorbed up to 1.3 mg of propiconazole per g substrate, calcined clays bound up to 12 mg of propiconazole per g substrate. The efficacy of the gibberellic acid biosynthesis inhibitor, uniconazole, and the most active brassinosteroid, brassinolide, was impacted similarly by the respective substrates. Conversely, gibberellic acid showed no distinct growth response in different media. Our results suggest that the reduction in efficacy of propiconazole, uniconazole, and brassinolide in bioassays when grown in calcined clay is caused by hydrophobic interactions between the plant growth regulators and the growth media. This was further confirmed by experiments using methanol-water solvent mixes with higher hydrophobicity values, which reduce the interaction of propiconazole and calcined clay.     

Near-isogenic lines of maize differing for glycinebetaine.

A series of near-isogenic glycinebetaine-containing and -deficient F8 pairs of Zea mays L. (maize) lines were developed. The pairs of lines differ for alternative alleles of a single locus; the wild-type allele conferring glycinebetaine accumulation is designated Bet1 and the mutant (recessive) allele is designated bet1. The near-isogenic lines were used to investigate whether glycinebetaine deficiency affects the pool size of the glycinebetaine precursor, choline, using a new method for glycinebetaine and choline determination: stable isotope dilution plasma desorption mass spectrometry. Glycinebetaine deficiency in maize was associated with a significant expansion of the free choline pool, but the difference in choline pool size was not equal to the difference in glycinebetaine pool size, suggesting that choline must down-regulate its own synthesis. Consistent with this, glycinebetaine deficiency was also associated with the accumulation of the choline precursor, serine. A randomly amplified polymorphic DNA marker was identified that detects the bet1 allele. In 62 F8 families tested the 10-mer primer 5'-GTCCTCGTAG produced a 1.2-kb polymerase chain reaction product only when DNA from Bet1/bet1 or bet1/bet1 lines was used as template. All 26 homozygous Bet1/Bet1 F8 families tested were null for this marker.     

Salt Tolerance of Glycinebetaine-Deficient and -Containing Maize Lines

Pairs of homozygous near-isogenic glycinebetaine-containing (Bet1/Bet1) and -deficient (bet1/bet1) F8 lines of Zea mays L. (maize) were tested for differences in salt (150 mM NaCl or 127.25 mM NaCl plus 22.5 mM CaCl2) tolerance. The Bet1/Bet1 lines exhibited less shoot growth inhibition (as measured by dry matter accumulation, leaf area expansion rate and/or, plant height extension rate) under salinized conditions in comparison to their nearisogenic bet1/bet1 sister lines. These growth differences were associated with maintenance of a significantly higher leaf relative water content, a higher rate of carbon assimilation, and a greater turgor in Bet1/Bet1 lines than in bet1/bet1 lines under salinized conditions. These results strongly suggest that a single gene conferring glycinebetaine accumulation (and/or a tightly linked locus) plays a key role in osmotic adjustment in maize.     

Serum T4, T3 and reverse T3 in ethanol fed rats.

To investigate the influence of chronic ethanol consumption on circulating thyroid hormone levels, male and female rats were given 20% ethanol as the only drinking solution daily for 8 weeks. Blood ethanol levels ranged 30–45 mg/L. In male rats serum T₄ decreased from the initial mean ± SD value of 5.2±1.4 to3.0 ±0.7 μg/dl; T₃ decreased from initial value of 97±14 to 66±11 ng/dl and rT₃ decreased from initial value of 19±9 to 10±1 ng/dl after 8 weeks of ethanol ingestion. Under similar experimental conditions, female rats showed a significant decrease in serum T₄ and rT₃ levels; however, T₃ levels decreased slightly but not significantly as compared to initial values. The results indicate adverse effect of chronic ethanol intake on serum thyroid hormone levels in rats.     

Effects of neem and spinosad on Ceratothripoides claratris (Thysanoptera: Thripidae), an important vegetable pest in Thailand, under laboratory and greenhouse conditions

Toxicity of three biopesticides, i.e., two neem products and spinosad, was determined on foliage-dwelling life stages of Ceratothripoides claratris (Shumsher) (Thysanoptera: Thripidae), a major thrips pest on tomatoes, Lycopersicon spp., in central Thailand. Direct and residual contact toxicities of NeemAzal-TS (1% azadirachtin) and systemic activity of NeemAzal-MD 5 (5% azadirachtin) affected the survival of first larval stage (L1) in a concentration-dependent manner. However, neither second larval stage (L2) nor adult survival was influenced by both neem products. On the contrary, spinosad caused 100% mortality in both larval stages and adults of C. claratris regardless of the concentrations tested. No strong ovicidal effects were detected in three different age groups of eggs (i.e., 1, 2, and 3 d old) topically treated with both NeemAzal-TS and spinosad. Residual toxicity was highest with fresh residues of NeemAzal-TS compared with 1-, 3-, 5-, and 7-d-old residues and in general was higher under laboratory than greenhouse conditions. Irrespective of the age of the spray residues, spinosad always caused 100% mortality in larvae and adults. Strongest systemic effects were observed in L1 larvae 1 d after soil drenching with NeemAzal-MD 5 at the highest concentration tested. Foliar and soil applications of NeemAzal-TS and NeemAzal-MD 5, respectively, did not cause any oviposition deterrent effects.     

Interaction of hemoglobin and its component alpha and beta chains with band 3 protein

The equilibrium binding of hemoglobin to isolated band 3 protein exhibited positive cooperativity [Hill coefficient = 1.65 +/- 0.1; total number of binding sites at pH 6.6 in 5 mM sodium phosphate buffer = 32 500 +/- 940 pmol/mg; Ka = (3.0 +/- 0.5) X 10(5) M-1]. The binding was reversible and ionic in nature as the bound hemoglobin was readily displaced by KCl, ATP, and 2,3-diphosphoglycerate, the latter two being more effective than KCl on a molar basis. The ratio of the interaction of hemoglobin to band 3 protein per se was 1:1, whereas the band 3 preparation as a whole (protein + lipids) was 3:1. Saturating levels of glyceraldehyde-3-phosphate dehydrogenase blocked only 33% of the total binding sites which were localized at the cytoplasmic segment; the remaining 67% was localized in lipids by their extraction with acetone. Reconstitution of acetone-extracted band 3 with phospholipid liposomes indicated phosphatidylserine as the binding site. The positive cooperativity in binding to acetone-extracted band 3 was increased (Hill constant = 2.1 +/- 0.1) compared to the band 3 preparation. After separation of the alpha and beta chains of hemoglobin, only the alpha chain binds to band 3 with positive cooperativity to an extent of 45-50% of native hemoglobin with similar affinity. The binding capacity of p-(hydroxymercuri)benzoate (HMB) derivatives of hemoglobin and its alpha chain was less than that of native hemoglobin, whereas HMB-beta chain or beta chain did not bind.(ABSTRACT TRUNCATED AT 250 WORDS)     

Costameric integrin and sarcoglycan protein levels are altered in a Drosophila model for Limb-girdle muscular dystrophy type 2H

Mutations in two different domains of the ubiquitously expressed TRIM32 protein give rise to two clinically separate diseases, one of which is Limb-girdle muscular dystrophy type 2H (LGMD2H). Uncovering the muscle-specific role of TRIM32 in LGMD2H pathogenesis has proven difficult, as neurogenic phenotypes, independent of LGMD2H pathology, are present in TRIM32 KO mice. We previously established a platform to study LGMD2H pathogenesis using Drosophila melanogaster as a model. Here we show that LGMD2H disease-causing mutations in the NHL domain are molecularly and structurally conserved between fly and human TRIM32. Furthermore, transgenic expression of a subset of myopathic alleles (R394H, D487N, and 520fs) induce myofibril abnormalities, altered nuclear morphology, and reduced TRIM32 protein levels, mimicking phenotypes in patients afflicted with LGMD2H. Intriguingly, we also report for the first time that the protein levels of βPS integrin and sarcoglycan δ, both core components of costameres, are elevated in TRIM32 disease-causing alleles. Similarly, murine myoblasts overexpressing a catalytically inactive TRIM32 mutant aberrantly accumulate α- and β-dystroglycan and α-sarcoglycan. We speculate that the stoichiometric loss of costamere components disrupts costamere complexes to promote muscle degeneration.     

Molluskan fasciclin-1 domain-containing protein: Molecular characterizationand gene expression analysis of fasciclin 1-like protein from disk abalone (Haliotis discus discus)

Cell-to-cell contacts play a key role in multicellular systems and organisms. Fasciclin-1 (FAS-1) is a lipid-linked membrane associated glycoprotein that is a member of a newly recognized family of cell adhesion molecules sharing features with the immunoglobulins, cadherins, integrins, and selectins. Here, we report the identification and molecular characterization of a novel FAS-1 domain-containing cDNA from disk abalone (Haliotis discus discus), including its gene expression profile and immune response to bacterial stimuli and tissue injuries. Designated as Abfac1, the 909 bp open reading frame (ORF) encodes 303 amino acid (aa) residues with a predicted molecular mass of 33 kDa and isoelectric (pI) value of 4.9. The aa sequence contains two FAS-1 domains and three conserved regions, FRa motif, H-box, and FRb motif. Phylogenetic analysis showed the closest relation to Jellyfish cell adhesion protein. In healthy abalone, Abfac1 expression is highest in hepatopancreas followed by mantle and lowest in digestive gland. In immune-stimulated abalones, relative Abfac1 mRNA expression was increased in hemocytes by ~ 11-fold at 48 h after the Vibrio parahaemolyticus infection, by 3.1-fold at 6 h after the Listeria monocytogenes infection and by ~ 9-fold at 6 h after the LPS injection. Similarly, tissue injuries caused significant increase of relative mRNA expression by 3.5-fold in hemocytes and by ~ 10-fold in mantle at 12 h post-injury. These results suggest that the novel member of the FAS-1 domain-containing protein family, Abfac1, may be involved in immune response and cell adhesion in disk abalone.