Evolution of a Humid Tropical Landscape in Northcentral Costa Rica as Deduced from Geomorphic and Pedogenic Evidence

The University of Kansas has long historical connections with Central America and the many Central Americans who have earned graduate degrees at KU. This work is part of the Central American Theses and Dissertations collection in KU ScholarWorks and is being made freely available with permission of the author through the efforts of Professor Emeritus Charles Stansifer of the History department and the staff of the Scholarly Communications program at the University of Kansas Libraries’ Center for Digital Scholarship.Progressive landscape changes in humid tropical provinces of southern San Carlos Canton in northcentral Costa Rica can be attributed to tectonic, volcanic, mass-wasting, and fluvial events. Spatial distribution of principal landform types and variations in degree of soil development of associated modern and buried soils are used to determine major episodes of landscape evolution- The two lines of evidence complement each other in that pedogenic evidence permits an assessment of temporal relationships between spatially disjunct landforms and of the magnitude of age differences between landforms, information unattainable from geomorphic evidence alone. Small hills of laharic origin, alluvial plains, and paired terraces are present in the Atlantic Lowland Province of southern San Carlos. The Piedmont Province contains tilted fault-block ridges, alluvial/laharic fans, alluvial plains, cinder cones, and volcanic ash mantles. Spatial segregation of differing landform types prevents assessment of relative landform ages for the region as a whole Duration of soil formation has exerted the greatest influence on pedogenesis? hence, degree of soil development provides a qualitative measure of soil age. Differences in soil development are revealed by silt/clay ratios, soil texture, free iron-oxide content, soil color, and illuvialclay content, in order of decreasing usefulness. Soils at an early, at an intermediate, and at an advanced stage of soil development are recognizable; ranking of individual soil groups within general age categories is possible on the basis of silt/clay ratios and soil texture. Absolute soil ages are inferred from silt/clay ratios in subsoil horizons. Knowledge of relative landform ages is greatly enhanced by pedogenic evidence. Pliocene tectonism, accompanied by explosive volcanic activity and laharic deposition, led to formation of four cinder cones In the eastcentral part of the Piedmont Province and small hills of laharic origin in the Atlantic Lowland Province of southern San Carlos. Further tectonism during the early Pleistocene created three tilted faultblock ridges in the western and central parts of the Piedmont Province. Consequent increase in fluvial aggradation initiated formation of alluvial plains in the Piedmont and Atlantic Lowland Provinces and, aided by intermittent laharic deposition, caused the buildup of alluvial/laharlc fans against the backslopes of tilted fault-block ridges. Upper portions of most alluvial/lahaxic landforms are late Pleistocene, those of alluvial plains in the Atlantic Lowland Province Recent in age. Explosive volcanic activity during the middle Pleistocene and late Holocene is responsible for pyroclastic surface deposits in the northeastern and southeastern parts of the Piedmont Province, respectively. The more recent volcanic event possibly took place at the time when increased fluvial degradation led to formation of paired terraces in the Atlantic lowland Province of the region

Evaluation of Media Components and Process Parameters in a Sensitive and Robust Fed-Batch Syngas Fermentation System with Clostridium ljungdahlii

The fermentation of synthesis gas, or syngas, by acetogenic bacteria can help in transitioning from a fossil-fuel-based to a renewable bioeconomy. The main fermentation products of Clostridium ljungdahlii, one of such microorganisms, are acetate and ethanol. A sensitive, robust and reproducible system was established for C. ljungdahlii syngas fermentation, and several process parameters and medium components (pH, gas flow, cysteine and yeast extract) were investigated to assess its impact on the fermentation outcomes, as well as real time gas consumption. Moreover, a closed carbon balance could be achieved with the data obtained. This system is a valuable tool to detect changes in the behavior of the culture. It can be applied for the screening of strains, gas compositions or media components, for a better understanding of the physiology and metabolic regulation of acetogenic bacteria. Here, it was shown that neither yeast extract nor cysteine was a limiting factor for cell growth since their supplementation did not have a noticeable impact on product formation or overall gas consumption. By combining the lowering of both the pH and the gas flow after 24 h, the highest ethanol to acetate ratio was achieved, but with the caveat of lower productivity

Investigating the Processing Potential of Ethiopian Agricultural Residue Enset/Ensete ventricosum for Biobutanol Production

The Enset plant is a potential food source for about 20 million Ethiopians. A massive amount of residual byproduct is discarded from traditional Ethiopian Enset food processing. This study shows a compositional analysis of Enset biomass and its use for biobutanol production. The Enset biomass was pretreated with 2% (w/v) NaOH or 2% (v/v) H2SO4 and subjected to enzymatic hydrolysis. The enzymatic hydrolysates were then fermented anaerobically by C. saccharoperbutylacetonicum DSM 14923. The majority of Enset biomass waste samples contained 36–67% cellulose, 16–20% hemicelluloses, and less than 6.8% lignin. In all alkali-pretreated Enset biomass samples, the enzyme converted 80–90% of the biomass to glucose within 24 h, while it took 60 h to convert 48–80% of the acid-pretreated Enset biomass. In addition, the alkali pretreatment method released more glucose than the acid pretreatment in all Enset biomass samples. After 72 h of ABE fermentation, 2.8 g/L acetone, 9.9 g/L butanol, and 1.6 g/L ethanol were produced from mixed Enset waste hydrolysate pretreated with alkali, achieving an ABE yield of 0.32 g/g and productivity of 0.2 g × L$^{−1}$ × h$^{−1}$, showing the first value of butanol produced from Enset biomass in the literature

Caproate production from Enset fiber in one-pot two-step fermentation using anaerobic fungi (Neocallimastix cameroonii strain G341) and Clostridium kluyveri DSM 555

Lignocellulosic biomass plays a crucial role in creating a circular bioeconomy and minimizing environmental impact. Enset biomass is a byproduct of traditional Ethiopian Enset food processing that is thrown away in huge quantities. This study aimed to produce caproate from Enset fiber using Neocallimastix cameroonii strain G$_{341}$ and Clostridium kluyveri DSM $_{555}$ in one-pot two-step fermentation

Not All That Glitters Is Gold: The Paradox of CO-dependent Hydrogenogenesis in Parageobacillus thermoglucosidasius

The thermophilic bacterium Parageobacillus thermoglucosidasius has recently gained interest due to its ability to catalyze the water gas shift reaction, where the oxidation of carbon monoxide (CO) is linked to the evolution of hydrogen (H$_{2}$) gas. This phenotype is largely predictable based on the presence of a genomic region coding for a carbon monoxide dehydrogenase (CODH—Coo) and hydrogen evolving hydrogenase (Phc). In this work, seven previously uncharacterized strains were cultivated under 50% CO and 50% air atmosphere. Despite the presence of the coo—phc genes in all seven strains, only one strain, Kp1013, oxidizes CO and yields H$_{2}$. The genomes of the H$_{2}$ producing strains contain unique genomic regions that code for proteins involved in nickel transport and the detoxification of catechol, a by-product of a siderophore-mediated iron acquisition system. Combined, the presence of these genomic regions could potentially drive biological water gas shift (WGS) reaction in P. thermoglucosidasius

Thermophilic Water Gas Shift Reaction at High Carbon Monoxide and Hydrogen Partial Pressures in Parageobacillus thermoglucosidasius KP1013

The facultatively anaerobic Parageobacillus thermoglucosidasius oxidizes carbon monoxide to produce hydrogen via the water gas shift (WGS) reaction. In the current work, we examined the influence of carbon monoxide (CO) and hydrogen (H$_2$) on the WGS reaction in the thermophilic P. thermoglucosidasius by cultivating two hydrogenogenic strains under varying CO and H$_2$ compositions. Microbial growth and dynamics of the WGS reaction were monitored by evaluating parameters such as pressure, headspace composition, metabolic intermediates, pH, and optical density. Our analyses revealed that compared to the previously studied P. thermoglucosidasius strains, the strain KP1013 demonstrated higher CO tolerance and improved WGS reaction kinetics. Under anaerobic conditions, the lag phase before the WGS reaction shortened to 8 h, with KP1013 showing no hydrogen-induced product inhibition at hydrogen partial pressures up to 1.25 bar. The observed lack of product inhibition and the reduced lag phase of the WGS reaction support the possibility of establishing an industrial process for biohydrogen production with P. thermoglucosidasius

Side-by-Side Comparison of Clean and Biomass-Derived, Impurity-Containing Syngas as Substrate for Acetogenic Fermentation with Clostridium ljungdahlii

Syngas, the product of biomass gasification, can play an important role in moving towards the production of renewable chemical commodities, by using acetogenic bacteria to ferment those gaseous mixtures. Due to the complex and changing nature of biomass, the composition and the impurities present in the final biomass-derived syngas will vary. Because of this, it is important to assess the impact of these factors on the fermentation outcome, in terms of yields, productivity, and product formation and ratio. In this study, Clostridium ljungdahlii was used in a fed-batch fermentation system to analyze the effect of three different biomass-derived syngases, and to compare them to equivalent, clean syngas mixtures. Additionally, four other clean syngas mixtures were used, and the effects on product ratio, productivity, yield, and growth were documented. All biomass-derived syngases were suitable to be used as substrates, without experiencing any complete inhibitory effects. From the obtained results, it is clear that the type of syngas, biomass-derived or clean, had the greatest impact on product formation ratios, with all biomass-derived syngases producing more ethanol, albeit with lesser total productivity

Comparison of different methods for preparation and characterization of total RNA from cartilage samples to uncover osteoarthritis in vivo

<p>Abstract</p> <p>Background</p> <p>The isolation of intact RNA can be very difficult when tissues are used that contain many RNAses or that are hard to homogenize, e.g. cartilage samples. Additionally, cartilaginous tissues are characterized by a low cellularity and an abundance of extracellular matrix (ECM) molecules. But given the growing interest in understanding pathogenesis of degenerative diseases, e.g. osteoarthritis (OA) and rheumatoid arthritis (RA), studies have to consider expression pattern of cells in its natural environment.</p> <p>Findings</p> <p>We compared the current RNA isolation methods for the extraction of high-quality RNA of snap-frozen biopsies from limited amounts of hypocellular cartilaginous tissue. The focus of the study was to gather information about procedure-related differences in RNA quality and yield. Here, we describe two protocols, the phenol/chloroform-free filter-based method (RN<it>Aqueous</it>™ kit) and the combined protocol (TRIzol^®/RNeasy Mini™ kit), working in a reproducible and reliable manner.</p> <p>Conclusions</p> <p>We conclude that preparation, storage, homogenization, and quality control are altogether critical steps for in-depth analysis of differential gene expression, especially in hypocellular tissues with highly crosslinked ECM like cartilage.</p

Process development for the elucidation of mycotoxin formation in Alternaria alternata

The black mould Alternaria alternata produces a wide diversity of mycotoxins which are of particular health concern. Since no maximum allowable limits are set for Alternaria toxins in food and feed, prevention of Alternaria infestations and mycotoxin spoilage is the only way to avoid health risks. Thus, the understanding of mycotoxin biosynthesis is essential. For that purpose, a reliable batch process in a 2 L bioreactor was established which enables the study of several parameters influencing the production of the mycotoxins alternariol (AOH), alternariol monomethylether (AME) and tenuazonic acid (TA) by A. alternata DSM 12633. Modified Czapek-Dox medium was used with glucose as carbon source and ammonium and nitrate as nitrogen sources. Consumption of carbon and nitrogen sources as well as formation of the three mycotoxins were monitored; the average data of five independent fermentations was plotted and fitted using a logistic equation with four parameters. Maximum mycotoxin concentrations of 3.49 ± 0.12 mg/L AOH, 1.62 ± 0.14 mg/L AME and 38.28 ± 0.1 mg/L TA were obtained

Draft Genome Sequence of the Oleaginous Yeast Apiotrichum porosum (syn. Trichosporon porosum) DSM 27194

Here, we present the draft genome sequence of Apiotrichum porosum DSM 27194 generated on PacBio platform. Characterization of this oleaginous yeast originally collected from the grassland in Karlsruhe Germany, revealed potential for its utilization as a source of single cell oil (SCO) and gluconic acid (GA). The availability of the genome sequence provides a valuable resource for the elucidation of the genetic processes determining SCO and GA biosynthesis