AJUR Volume 20 Issue 1 (June 2023)

Click on this link to download the full high-definition interactive pdf for AJUR Volume 20 Issue 1 (June 2023) or https://doi.org/10.33697/ajur.2023.075

Links to individual manuscripts, abstracts, and keywords are provided below.

p.3. Divestment Movements over Environmental Issues: The Brazilian Amazon Case

Pedro Eymael


ABSTRACT: Devastating forest fires in Brazil’s Amazon rainforest, one of the most important biomes for Earth’s climate balance, have captured the world’s attention in 2019 and 2020. Foreign governments, non-governmental organizations, and institutional investors pressured Brazilian President Jair Bolsonaro to act and control the situation. Within this context, institutional investors threatened to divest from companies potentially linked to the wildfires and to sell government bonds, creating a divestment movement. Against this background, this article shows that Bolsonaro’s responses varied for each of the groups criticizing the handling of the environmental situation. It is argued that the Brazilian government adopted a more conciliatory tone and took more concrete actions when responding to institutional investors’ demands, compared to the responses for foreign governments and non-governmental organizations (NGOs). Based on fifteen in-depth interviews conducted in 2021 with professionals involved in this divestment case, the paper concludes that institutional investors played a key role in Bolsonaro’s winning coalition and electoral aspirations. Moreover, the shortage of financial capital due to the COVID-19 pandemic created further incentives for Bolsonaro to avoid conflicts with institutional investors. KEYWORDS: Divestment; Amazon Rainforest; Wildfires; Investors; Climate Change; Brazil; Politics

p.27. Using Coral Color to Indicate Coral Health in Five Caribbean Species

Gabriella Herrera, Alexandra M. Good, Alexander Hirota, Catherine Razal, Nicole Gaertner, Justin Sefcik, Jesse Gilbert, & Keisha D. Bahr


ABSTRACT: Coral reefs are one of the most biodiverse and productive ecosystems on Earth, and color has been shown to indicate coral health in Australian and Hawaiian reef systems. However, no standardized method exists to quantify coral health for Caribbean corals. Therefore, a health assessment card using coral color was developed for five species of Caribbean corals to monitor coral health non-invasively. To quantify coral health, individual corals of each species were photographed in a controlled environment to develop color profiles. Simultaneously, nondestructive measurements of “health” were quantified by measuring photosynthetic efficiency (Fv/Fm) using pulse amplitude modulation (PAM) fluorometry, which determines how efficiently the symbiotic algae provides energy to the coral host. The results of this work successfully corresponded photosynthetic efficiency to coral color for five dominant species of Caribbean corals to develop a Coral Health Assessment Card for Caribbean reefs. Implementing a standardized assessment of symbiont performance can assist in monitoring changes in coral health, which can consequently be implemented into long-term and widespread monitoring projects to track overall Caribbean reef health.
KEYWORDS: Photosynthetic Efficiency, Symbiodinium spp., Coral Bleaching, Pulse-amplitude Modulated Fluorometry, Health Assessment

p.37. Synthesis and Palladium-Catalyzed Cross-Coupling of an Alkyl-Substituted Alkenylboronic Acid Pinacol Ester with Aryl Bromides

Shoma Mukai & Nathan S. Werner


ABSTRACT: The palladium-catalyzed cross-coupling reaction of alkyl-substituted alkenylboron reagents with aryl halides is a versatile method to introduce a hydrophobic hydrocarbon chain onto organic compounds of interest. The application of the cross-coupling reaction is enabled by synthetic methods for the preparation of alkenylboron reagents. The geometrically pure, alkyl-substituted alkenylboron reagent, (E)-octenylboronic acid pinacol ester, was prepared by 9-BBN-catalyzed hydroboration reaction of 1-octene with pinacolborane in refluxing 1 M THF solution. This reagent was then evaluated in palladium-catalyzed cross-coupling reactions with aryl bromides. The highest yield of the (E)-1-phenyloctene was obtained when SPhos was used as the ligand, K2CO3 was used as the base, and DMF was used as the reaction solvent. Other electron-rich, electron-poor, sterically hindered, and heteroaromatic substrates produced the corresponding (E)-1-phenyloctene derivatives in moderate to good yield.
KEYWORDS: Organic synthesis; Aryl alkene synthesis; Palladium-catalyzed cross-coupling; Suzuki-Miyaura reaction; Stereocontrolled alkene preparation; Hydroboration; 9-Borobicyclo[3.3.1]nonane; Reaction optimization

p.47. Spawning Conditions Affect Clutch Probability and Size in Laboratory-Housed Zebrafish (Danio rerio)

Sydni Anderson, Elizabeth Sipes, Megan Franke, & Dena R. Hammond-Weinberger


ABSTRACT: Zebrafish are common experimental models used in biological studies that are bred and raised in laboratory settings. Published studies, anecdotal evidence, and industry practices are variable and offer conflicting suggestions on maximizing reproductive success, particularly regarding sex ratios and segregating males and females before spawning. This study identified conditions that promote maximum reproductive success (clutch probability and average clutch size) in zebrafish. Clutch probability was higher when females were seven to ten months old and bred in groups with equal sex ratios and an artificial spawning substrate in the winter or spring. Clutch size was significantly larger when females were seven to ten months old, outnumbered by males, and bred with an artificial spawning substrate. Optional spawning substrates (marbles and plants) improved reproductive success, whereas other parameters had no impact. These data support the implementation of simple steps that reliably maximize reproductive success of laboratory zebrafish.
KEYWORDS: Reproduction; Breeding; Seasonality; Behavior; Substrate; Sex Ratios; Captivity; Eggs

p.59. Color Saturation: Upper and Lower Percentage Histogram Manipulation

Kyra Obert , Maria Schudt , & Ian Bentley


ABSTRACT: There are various color correction techniques that can be applied to digital photographs to account for environmental lighting variations. This manuscript contains a proposed method for such color correction. The method involves saturating an image by a specified percentage of its pixels via upper and lower percentage histogram manipulation using the image’s RGB histograms. Variations of this new technique, the white balance (WB) correction method, and a multivariable fit are used to test its performance against common color correction techniques. The findings demonstrate that the upper and lower percentage histogram manipulation method is not only more applicable to photos because it doesn’t require calibration regions to be sampled but it is also more consistent in its correction of photos when there are substantial gray scale features (e.g. a black and white grid or text). Our motivation for testing these techniques is to find the most robust color correction technique that is broadly applicable (not requiring a color checker chart) and is consistent across different lighting.
KEYWORDS: Color Correction; Histogram Manipulation; Saturation; White Balance; Scientific Image Analysis; Color Comparisons; Euclidean Distance; Standard Deviation; Color Difference

p.77. Overexpression of MMACHC Prevents Craniofacial Phenotypes Caused by Knockdown of znf143b

Isaiah Perez, Nayeli G. Reyes-Nava, Briana E. Pinales, & Anita M. Quintana


ABSTRACT: ZNF143 is a sequence-specific DNA binding protein that regulates the expression of protein-coding genes and small RNA molecules. In humans, ZNF143 interacts with HCFC1, a transcriptional cofactor, to regulate the expression of downstream target genes, including MMACHC, which encodes an enzyme involved in cobalamin (cbl) metabolism. Mutations in HCFC1 or ZNF143 cause an inborn error of cobalamin metabolism characterized by abnormal cbl metabolism, intellectual disability, seizures, and mild to moderate craniofacial abnormalities. However, the mechanisms by which ZNF143 mutations cause individual phenotypes are not completely understood. Defects in metabolism and craniofacial development are hypothesized to occur because of decreased expression of MMACHC. But recent results have called into question this mechanism as the cause for craniofacial development. Therefore, in the present study, we implemented a loss of function analysis to begin to uncover the function of ZNF143 in craniofacial development using the developing zebrafish. The knockdown of znf143b, one zebrafish ortholog of ZNF143, caused craniofacial phenotypes of varied severity, which included a shortened and cleaved Meckel’s cartilage, partial loss of ceratobranchial arches, and a distorted ceratohyal. These phenotypes did not result from a defect in the number of total chondrocytes but were associated with a mild to moderate decrease in mmachc expression. Interestingly, expression of human MMACHC via endogenous transgene prevented the onset of craniofacial phenotypes associated with znf143b knockdown. Collectively, our data establishes that knockdown of znf143b causes craniofacial phenotypes that can be alleviated by increased expression of MMACHC.
KEYWORDS: ZNF143; MMACHC; Vertebrate abnormalities; Cobalamin; cblX-like syndrome; Chondrocytes; Neural crest cells; Hyosymplectic