The effects of El Niño‐Southern Oscillation events on intertidal seagrass beds over a long‐term timescale

El Niño‐Southern Oscillation (ENSO) events can cause dramatic changes in marine communities. However, we know little as to how ENSO events affect tropical seagrass beds over decadal timescales. Therefore, a diverse array of seagrass (Thalassia hemprichii) habitat types were surveyed once every 3 months for 16 years (January 2001 to February 2017) in a tropical intertidal zone that is regularly affected by both ENSO events and anthropogenic nutrient enrichment. La Niña and El Niño events had distinct effects on the biomass and growth of T. hemprichii. During La Niña years, higher (a) precipitation levels and (b) seawater nitrogen concentrations led to increases in seagrass leaf productivity, canopy height, and biomass. However, the latter simultaneously stimulated the growth of periphyton on seagrass leaves; this led to decreases in seagrass cover and shoot density. More frequent La Niña events could, then, eventually lead to either a decline in intertidal seagrass beds or a shift to another, less drought‐resistant seagrass species in those regions already characterized by eutrophication due to local anthropogenic activity.     

Restoration of tropical forests requires more than just planting trees,a lot more…

Forest restoration is an important tool for combating climate change and protecting biodiversity. In this issue of Applied Vegetation Science, Garcia et al. show that alone, planting trees is insufficient for fully restoring rain forest complexity. This study highlights the need for longer‐term restoration plans, including enrichment plantings that speed the recovery of non‐tree forest components once planted trees have established.     

Immunotherapy using algal‐produced Ara h 1 core domain suppresses peanut allergy in mice

Peanut allergy is an IgE‐mediated adverse reaction to a subset of proteins found in peanuts. Immunotherapy aims to desensitize allergic patients through repeated and escalating exposures for several months to years using extracts or flours. The complex mix of proteins and variability between preparations complicates immunotherapy studies. Moreover, peanut immunotherapy is associated with frequent negative side effects and patients are often at risk of allergic reactions once immunotherapy is discontinued. Allergen‐specific approaches using recombinant proteins are an attractive alternative because they allow more precise dosing and the opportunity to engineer proteins with improved safety profiles. We tested whether Ara h 1 and Ara h 2, two major peanut allergens, could be produced using chloroplast of the unicellular eukaryotic alga, Chlamydomonas reinhardtii. C. reinhardtii is novel host for producing allergens that is genetically tractable, inexpensive and easy to grow, and is able to produce more complex proteins than bacterial hosts. Compared to the native proteins, algal‐produced Ara h 1 core domain and Ara h 2 have a reduced affinity for IgE from peanut‐allergic patients. We further found that immunotherapy using algal‐produced Ara h 1 core domain confers protection from peanut‐induced anaphylaxis in a murine model of peanut allergy.     

Differential effects of follicle-stimulating and luteinizing hormones on testosterone production by mouse testes

In adult mice, direct intratesticular injection of ovine follicle-stimulating hormone (o-FSH-13; AFP 2846-C, from NIAMDD, less than 1% LH contamination) at 10, 100 or 1000 ng significantly elevated concentrations of testosterone (T) within the testis. These effects were rapid, with peak values attained by 15 min, and transient, with return to values comparable to that in the contralateral, saline-injected testis within 90 min. Intratesticular injection of FSH (1 microgram) significantly increased testicular T levels in 15- and 60-day old mice. This contrasted with the effects of intratesticular administration of human chorionic gonadotropin (hCG), which stimulated T production significantly at 30 days of age through adulthood. In adult mice, the equivalent LH to the possible contamination in the FSH preparation (1 ng) had no effect. Intratesticular injection of 10 ng LH produced comparable stimulation to that by 100 ng FSH (approximately 7-fold). Systemic pre-treatment with a charcoal-treated porcine follicular fluid (PFF) extract for 2 days reduced plasma FSH levels [86 +/- 17 (5) vs 700 +/- 8 (6); P less than 0.05], but had no effect on plasma LH. Twenty-four hours after the last treatment, the response to intratesticular injection of hCG (2.5 mIU), FSH (100 ng) or LH (10 ng) was also significantly attenuated in these mice. Intratesticular injection of PFF had no direct effect on testicular T levels. In vitro T production in the presence of hCG, LH or FSH were differentially affected by the concentrations of calcium (Ca2+) or magnesium (Mg2+) in the incubation media. The stimulatory effects of FSH were apparent at significantly lower levels of Ca2+ or Mg2+, than were those of LH or hCG. The results of these studies indicate that FSH is capable of stimulating testicular T production. Furthermore, the responsiveness to FSH is qualitatively different than that to LH/hCG in terms of the age pattern, as well as the dependence on Ca2+ or Mg2+. In addition, plasma FSH levels appear to influence testicular responsiveness to direct exogenous administration of gonadotropins. These studies indicate that FSH stimulation of T production can be differentiated from those of LH, and that these effects of FSH can be observed under physiological conditions.     

Florigenic Acid from fungal culture

The extraction procedures which have been successfully employed in the preparation of a florigenic principle from the tissues of Xanthium, are applicable to the derivation of an entity of similar activity from Calonectria culture. The Xanthium principle is acedic, with pK_a values characteristic of a carboxylic acid (6). Although definitive chemical comparisons have not been completed, the extraction and solvent partition procedures that have been applicable to the extraction of the active entity from higher plant tissues have yielded florigenic preparations from fungal culture. The chemical principle from higher plant tissue may be the same or similar to the florigenic agent of Calonectria.

The many responses of higher plants to growth regulators produced by micro-organisms are well known. The presence of a flower-producing principle from Calonectria (Fusarium) rigidiuscula parallels closely the pattern exhibited by those fungal species capable of the production of auxin and gibberellins.

     

Ultraviolet Dichroism of fd Bacteriophage

The internal structure of the bacterial virus fd was investigated by ultraviolet dichroism of virus solutions oriented by flow through a small capillary tube. The dichroism was found to be positive for wavelengths longer than 262 mμ and shorter than 239 mμ, and negative for the intermediate wavelengths. The magnitude of the effect was at all times small, with dichroic ratios of 1.22 and 0.83 at 280 mμ and 250 mμ, respectively. the intuitive interpretation that this was the result of the addition of negative DNA dichroism and positive protein dichroism was confirmed by the application of a simple theory which allowed the calculation from protein and DNA absorption data of a dichroism curve closely approximating the experimental one. The parameters arrived at by this procedure indicate a semiangle of 25° ± 5° for a cone described by the normals to the DNA base planes inside the virus. The protein absorbers tryptophan and probably tyrosine were found to be oriented on the average relatively parallel to the longitudinal axis of the virus.     

Degradation of the gamma-Carboxyl-Containing Diarylpropane Lignin Model Compound 3-(4'-Ethoxy-3'-Methoxyphenyl)-2-(4'-Methoxyphenyl)Propionic Acid by the Basidiomycete Phanerochaete chrysosporium

The white-rot basidiomycete Phanerochaete chrysosporium metabolized 3-(4'-ethoxy-3'-methoxyphenyl)-2-(4'-methoxyphenyl)propionic acid (V) in low-nitrogen, stationary cultures, conditions under which ligninolytic activity is expressed. The ability of several fungal mutant strains to degrade V reflected their ability to degrade [C]lignin to CO(2). 1-(4'-Ethoxy-3'-methoxyphenyl)-2-(4'-methoxyphenyl)-2- hydroxyethane (VII), anisyl alcohol, and 4-ethoxy-3-methoxybenzyl alcohol were isolated as metabolic products, indicating an initial oxidative decarboxylation of V, followed by alpha, beta cleavage of the intermediate (VII). Exogenously added VII was rapidly converted to anisyl alcohol and 4-ethoxy-3-methoxybenzyl alcohol. When the degradation of V was carried out under O(2), O was incorporated into the beta position of the diarylethane product (VII), indicating that the reaction is oxygenative.     

Degradation of the γ-Carboxyl-Containing Diarylpropane Lignin Model Compound 3-(4′-Ethoxy-3′-Methoxyphenyl)-2-(4″-Methoxyphenyl)Propionic Acid by the Basidiomycete Phanerochaete chrysosporium

The white-rot basidiomycete Phanerochaete chrysosporium metabolized 3-(4′-ethoxy-3′-methoxyphenyl)-2-(4″-methoxyphenyl)propionic acid (V) in low-nitrogen, stationary cultures, conditions under which ligninolytic activity is expressed. The ability of several fungal mutant strains to degrade V reflected their ability to degrade [¹⁴C]lignin to ¹⁴CO₂. 1-(4′-Ethoxy-3′-methoxyphenyl)-2-(4″-methoxyphenyl)-2- hydroxyethane (VII), anisyl alcohol, and 4-ethoxy-3-methoxybenzyl alcohol were isolated as metabolic products, indicating an initial oxidative decarboxylation of V, followed by α, β cleavage of the intermediate (VII). Exogenously added VII was rapidly converted to anisyl alcohol and 4-ethoxy-3-methoxybenzyl alcohol. When the degradation of V was carried out under ¹⁸O₂, ¹⁸O was incorporated into the β position of the diarylethane product (VII), indicating that the reaction is oxygenative.     

Probing ecosystem health: a multi-disciplinary and multi-trophic assay strategy

The ecosystem health of stressed environments in the Great Lakes has been evaluated simultaneously by means of a battery of structural and functional tests based on current technology and involving various trophic levels. These tests attempt to assess ecosystem health at the organism level and simultaneously focus on water-borne and sediment-bound toxicities. The use of structural indicators has been successfully demonstrated. Similarly, functional tests were selectively chosen across various trophic levels and included size-fractionated primary productivity (filtered versus unfiltered assays), and Colpidium, Daphnia, Hyalella, and Pontoporeia assays. Some of the emerging techniques such as in situ plankton cages (I.P.C.), microcomputer-based chlorophyll fluorescence (Video Analysis System), and other assays are discussed. The multi-trophic and multi-disciplinary battery of tests followed in our laboratory adopts a field-to-laboratory approach. The availability of diverse bioassays have placed toxicologists and environmentalists in a position where they are now better equipped to probe the complexities of ecosystem health and its management.Dedicated to the memory of my mother who was a great teacher, guide and an incredible source of inspiration.