Assessment of Four Solvents for Extraction and Analysis of the Chemical Composition of Sansevieria Extrafoliar Nectar Drops by Gas Chromatography-mass Spectrometry

In the latter part of the 20th century, much effort was devoted to elucidating the chemical constituents of floral and extrafloral nectar secretions, with the primary aim of understanding their ecological roles, especially in regards to attracting pollinators. But, nearly all these studies focused on determining sugar and amino acid constituents. Only a few studies have reported more comprehensive assessments of the organic chemical constituents of plants, with none of those reporting such efforts for Sansevieria taxa (common houseplants known to purify air by bioaccumulating pollutants). To address this knowledge gap, we evaluated the efficacy of four organic solvents with distinct polarities (dichloromethane (DCM), ethyl acetate, toluene and hexane) to extract the most diverse suite of organic compounds from extrafoliar nectar drops (n = 12) secreted by motherin-law’s-tongue plant (Sansevieria spp.). Each solvent exhibited unique extraction efficiencies, with DCM extracting the greatest number of unique compounds (141), followed by hexane (113), ethyl acetate (58) and toluene (43). Compound class distributions varied with solvent type, with aliphatic hydrocarbons dominating in all but the ethyl acetate extracts. We detected 105 unique aliphatic compounds in the DCM extracts, followed by 69, 28 and 9 in the hexane, toluene and ethyl acetate extracts, respectively. Alcohols predominated in the ethyl acetate extracts. We are aware of no published studies reporting such analytical determinations of the organic compound inventories of Sansevieria extrafoliar nectars. Validation of this methodology provides the impetus to study various other plant secretions of known and unknown utility

Identification and Characterization of Fungal Isolates from Land-applied Sewage Sludge

Approximately eight million dry tons of sewage sludge is generated in the U.S. each year, with more than half of that now land-applied as the primary method of disposal. Despite the proliferation of this practice, little is known about the microbial constituents of these noxious materials. To address this knowledge gap, we isolated and characterized fungi present in archived samples of land-disposed sewage sludge collected from the Snoqualmie National Forest (Washington State). Sludge samples were resuspended in sterile water and 15 fungal isolates were selected and purified on sabouraud dextrose agar plates supplemented with 50 mg/L of chloramphenicol. Fungal morphology was assessed and photodocumented following growth on sabouraud dextrose agar, potato dextrose agar, yeast maltose agar, and malt extract agar. Additionally, pH and temperature tolerance was assessed by growth in liquid cultures of sabouraud dextrose broth from 0 ºC to 50 ºC and determined from pH 2 to 11 at 28 ºC. Carbon source utilization was assessed using Biolog Filamentous Fungi plates. Amplification and sequencing of the ITS region, commonly used in fungal phylogenetic analysis, is in progress to identify each isolate. Phenotypic assessments of growth, carbon utilization, and lactophenol cotton blue staining revealed that sludge-associated fungi are quite varied in size and appearance, but commonly grow in a mesophilic range (10-40 ºC and pH 4-10). Interspecies variation is further evident in the percentage of 31 carbon sources utilized (63-100%). To our knowledge, this work represents the first reported assessment of the fungal community in sewage sludge wastes disposed in the Snoqualmie National Forest

Characterizing the Volatilome of Land-disposed Sewage Sludge Under Seasonal Temperature Regimes

About eight million dry tons of sewage sludge waste is generated in the US annually, with more than half of that now land-disposed on agricultural and forested lands. Though containing essential plant nutrients, sludge also harbors complex mixtures of volatile organic compounds (VOCs) that result in toxic emissions therefrom. While ecotoxic impacts to sludged ecosystems are a primary concern, the stifling emissions are most obvious to and disconcerting for the public, which has led to increasing concerns for the safety of this practice. The large-scale disposal of sludge in the temperate rainforests of the Puget Sound Watershed has resulted in acute toxicity to macrobiota, and despite escalating concerns for detrimental impacts, little is known about the total VOC inventories, or “volatilomes,” of these complex wastes. To address this knowledge gap, we characterized VOC emissions from forest-disposed sewage sludge over a range of seasonal temperature regimes. We also incubated sludge samples at the more extreme 100 o C to assess the “complete volatilome.” After 1-hr incubations in gastight vials, VOCs accumulated in the headspace were sampled with a gastight syringe and analyzed with gas chromatography-mass spectrometry to generate distinct chemical fingerprints of sludge sample volatilomes over the range of temperatures. Total integrated chromatographic peak areas increased with temperature, indicating increased VOC production. Sludge volatilomes were dominated by a multitude of aliphatics and aromatics, with comparatively lesser emissions of alcohols, esters, aldehydes, terpenes, and nitrogen-, sulfur-, and halogen-containing compounds

Profiling Volatile Constituents of Homemade Preserved Foods Prepared in Early 1950s South Dakota (USA) Using Solid-Phase Microextraction (SPME) with Gas Chromatography–Mass Spectrometry (GC-MS) Determination

An essential dimension of food tasting (i.e., flavor) is olfactory stimulation by volatile organic compounds (VOCs) emitted therefrom. Here, we developed a novel analytical method based on solid-phase microextraction (SPME) sampling in argon-filled gas sampling bags with direct gas chromatography⁻mass spectrometry (GC-MS) determination to profile the volatile constituents of 31 homemade preserves prepared in South Dakota (USA) during the period 1950⁻1953. Volatile profiles varied considerably, but generally decreased in detected compounds, complexity, and intensity over three successive 2-h SPME sampling periods. Volatile profiles were generally predominated by aldehydes, alcohols, esters, ketones, and organic acids, with terpenoids constituting much of the pickled cucumber volatiles. Bisphenol-A (BPA) was also serendipitously detected and then quantified in 29 samples, at levels ranging from 3.4 to 19.2 μg/kg, within the range of levels known to induce endocrine disruption effects. Absence of BPA in two samples was attributed to their lids lacking plastic liners. As the timing of their preparation coincides with the beginning of BPA incorporation into consumer products, these jars may be some of the first BPA-containing products in the USA. To the best of our knowledge, this is the first effort to characterize BPA in and volatile profiles of rare historical foods with SPME