Effects of temperature on Zooxanthellae strains in coral species Rhodactis rhodostoma

ABSTRACT Effects of temperature on Zooxanthellae strains in coral species Rhodactis rhodostoma. (May 2014) McKensie Daugherty Department of Biology Texas A&M University Research Advisor: Dr. Duncan MacKenzie Department of Biology Coral reefs are among the most diverse and fragile ecosystems in the ocean. Corals living in lighted zones can have a mutualistic symbiosis with algal dinoflagellates known as Zooxanthellae, specifically the genus Symbiodinium. In the event of stress from the environment (e.g. greater water temperature, acidity, or light permeation), coral can expel Zooxanthellae from their tissues in a process called bleaching. Bleaching is reversible, and it is possible for corals to repopulate with Zooxanthellae strains that are genetically distinct from the original symbiont and thus potentially better suited for the stressing environment. To determine whether this process of bleaching and repopulation could be studied in a small volume captive recirculating system, I took tissues samples from the soft coral Rhodactis rhodostoma held in the Great Aggie Reef, a 135 gallon reef display tank in Texas A&M University’s Biology Department, before and after exposure to increased temperature stress. To determine whether Zooxanthellae were expelled, I used a polymerase chain reaction-based technique to detect the presence of the symbiont-specific ITS1 gene in coral tissue. Whereas more rapid temperature increases were fatal to corals, a gradual increase to 32 degrees was successful in inducing a loss of ITS1 gene expression in surviving corals. These results suggest that this recirculating system may be suitable for further study of coral bleaching and repopulation with Zooxanthellae under controlled conditions

Post-Soviet hybrid-regimes: Elements of stability

The collapse of the Soviet Union in 1991 gave birth to many new independent states. Many of these states have developed regimes with both democratic and authoritarian elements, but they are not transitional democracies or transitional authoritarian regimes. Many scholars look at how to classify these regimes, but not at how the elements of the regime lead to its stability. Why are post-Soviet regimes stable? Discovering what makes these regimes stable can help us establish behavioral norms and aid us in future political and economic endeavors with the country in question. Although evaluating each element of hybrid-regimes would be ideal due to the current lack of information on hybrid-regimes in general, I would look at three main elements to determine their link to stability: civil society, effective (internal) governance, and international power. This study would help future policy makers and scholars alike to form opinions about, make decisions about and plan interactions with hybrid-regimes with solid information at their disposal

Transcriptomic Response of Karenia brevis to Environmental Stress

Karenia brevis is a toxic, marine phytoplankton that forms harmful algal blooms in the Gulf of Mexico. This toxicity is due to the production of ladder-frame polyketides known as brevetoxins, for which the production pathway and function in the cell are not known. Osmotic stress has been shown to increase the production of brevetoxin in K. brevis, and recent studies implicate the toxin as linked to the function of light harvesting complex II in the thylakoid membrane. Understanding if whether brevetoxin production and photosynthetic stress are linked in an osmotic shock response will shed further light on its function in the cell. Using K. brevis clones with high, average, low, and non-detectable levels of brevetoxin, we explored the response to osmotic stress using analysis of differential gene expression, measurements of PAM fluorometry, and production of the known osmolyte glycerol. Brevetoxin-producing clones of K. brevis showed lower expression in Photosystem II genes, and correspondingly lower photosynthetic efficiencies and intracellular glycerol concentrations in response to stress. In contrast, clones that produce non-detectable and low toxin levels showed no significant stress response, and also showed a deficiency in Non-Photochemical Quenching (NPQ) compared to toxic cultures. This observation supports the potential link between reactive oxygen species and NPQ pathways that is related to the presence of brevetoxin in K. brevis. Further, brevetoxin producing K. brevis clones respond to osmotic stress by utilizing photosynthesis for osmoacclimation and through small molecule degradation, in particular intracellular photosynthetically derived glycerol, whereas the low and non-detectable clones do not

Transcriptomic Response of Karenia brevis to Environmental Stress

Karenia brevis is a toxic, marine phytoplankton that forms harmful algal blooms in the Gulf of Mexico. This toxicity is due to the production of ladder-frame polyketides known as brevetoxins, for which the production pathway and function in the cell are not known. Osmotic stress has been shown to increase the production of brevetoxin in K. brevis, and recent studies implicate the toxin as linked to the function of light harvesting complex II in the thylakoid membrane. Understanding if whether brevetoxin production and photosynthetic stress are linked in an osmotic shock response will shed further light on its function in the cell. Using K. brevis clones with high, average, low, and non-detectable levels of brevetoxin, we explored the response to osmotic stress using analysis of differential gene expression, measurements of PAM fluorometry, and production of the known osmolyte glycerol. Brevetoxin-producing clones of K. brevis showed lower expression in Photosystem II genes, and correspondingly lower photosynthetic efficiencies and intracellular glycerol concentrations in response to stress. In contrast, clones that produce non-detectable and low toxin levels showed no significant stress response, and also showed a deficiency in Non-Photochemical Quenching (NPQ) compared to toxic cultures. This observation supports the potential link between reactive oxygen species and NPQ pathways that is related to the presence of brevetoxin in K. brevis. Further, brevetoxin producing K. brevis clones respond to osmotic stress by utilizing photosynthesis for osmoacclimation and through small molecule degradation, in particular intracellular photosynthetically derived glycerol, whereas the low and non-detectable clones do not

Impacts of a New Seasonal Work Program on Rural Household Incomes in the Pacific

Seasonal work programs are increasingly advocated by international aid agencies as a way of enabling both developed and developing countries to benefit from migration. They are argued to provide workers with new skills and allow them to send remittances home, without the receiving country having to worry about long-term assimilation and the source country worrying about permanent loss of skills. However, formal evidence as to the development impact of seasonal worker programs is non-existent. This paper provides the first such evaluation, studying New Zealand's new Recognized Seasonal Employer (RSE) program which allows Pacific Island migrants to work in horticulture and viticulture in New Zealand for up to seven months per year. We use baseline and follow-up waves of surveys we are carrying out in Tonga To form difference-in-difference and propensity score matching estimates of short-term impacts on household income and consumption

Tomato Flower Detection and Three-Dimensional Mapping for Precision Pollination

It is estimated that nearly 75% of major crops have some level of reliance on pollination. Humans are reliant on fruit and vegetable crops for many vital nutrients. With the intensification of agricultural production in response to human demand, native pollinator species are not able to provide sufficient pollination services, and managed bee colonies are in decline due to colony collapse disorder, among other issues. Previous work addresses a few of these issues by designing pollination systems for greenhouse operations or other controlled production systems but fails to address the larger need for development in other agricultural settings with less environmental control. In response to this crisis, this research aims to act as a vital first step towards the development of a more robust autonomous pollination system for agricultural crop production. The main objective of this research is to develop a flower detection and mapping system for a field crop setting. This research presents a method to detect and localize tomato flowers within a three-dimensional (3D) region. Tomato plants were grown in a raised-bed garden where images were collected of the overhead view of the plants. Images were then stitched together using a photogrammetry technique, accomplished by the Pix4Dmapper software, to form an orthomosaic and 3D representation of the raised-bed garden from a high spatial resolution aerial view. Various machine learning architectures were trained to detect tomato flowers from overhead images and were then tested on the orthomosaic images produced by the Pix4D software. The coordinates of the detected flowers in the orthomosaic were then compared to the 3D model representation to find approximate 3D coordinates for each of the flowers relative to a predefined origin. This research serves as a first step in autonomous pollination by presenting a way for machine vision and machine learning to be used to identify the presence and location of flowers on tomato crops. Future work will aim to expand flower detection to other crops varieties in varying field conditions

A Study of Counties for Big Country CASA Expansion

This study focuses on the need for Court Appointed Special Advocates (CASA) to expand to surrounding counties. These counties include Taylor (where BCC is housed), Callahan, Coleman, Fisher, Jones, and Shackelford. Using a descriptive design, this study uses public data from the Texas Department of Family Protective Services (TDFPS) to analyze data from counties with CASA (Taylor County) and without a CASA (the surrounding counties). Various descriptive analyses were conducted to examine major foster care outcomes of the counties for ten years (2011 through 2020) such as permanency outcome (exit), length of time in care, and number of placements. The results show that there are counties that could possibly benefit from CASA expanding to their counties. These counties are Coleman, Jones, and possibly Callahan. The county and foster care size of Shackelford and Fisher do not justify expanding

National Beef Quality Audit – 2016: A Survey of the Market Cow and Bull Industry to Discover Avenues for Improving Quality and Enhancing Value of Beef

The National Beef Quality Audit – 2016 marks the fourth iteration in a series assessing the quality of live beef and dairy cows and bulls and their carcass counterparts. Conducted from March through December of 2016, trailers (n = 154), live animals (n = 5470), hide-on carcasses (n = 5279), hide-off hot carcasses (n = 5510), chilled carcasses (n = 4285), and offal items (n = 4800) were surveyed in 18 commercial packing facilities throughout the United States. Cattle were hauled in all types of trailers for a mean distance of 455.7 km for 6.7 h and had a mean of 2.3 m² of space during transit. Of the mixed gender loads of cattle arriving at the packing facility, cows and bulls were not segregated on 64.4% of the trailers surveyed. When assessed for mobility, 81.3% of cattle surveyed were sound. The mean body condition score for beef animals was 4.7 and for dairy cows and bulls was 2.6 and 3.3, respectively. Since the previous National Market Cow and Bull Beef Quality Audit (2007), dairy cattle have trended to be lighter muscled, yet fatter. Of cattle surveyed, 12.0% had horns, and 63.2% had no visible live animal defects. Beef cattle were primarily black-hided, while dairy cattle were primarily Holstein-patterned. Just over half (56.0%) of the cattle had no mud contamination on the hide, and an additional 34.1% only had small amounts of mud on the hide. Native (unbranded) hides were observed on 77.3% of cattle. Carcass bruising was evident on 64.1% of cow carcasses and 42.9% of bull carcasses. However, over half of all cattle surveyed had bruises which were only minimal in severity. Nearly all cattle (98.4%) were free of visible injection site lesions. Harvest floor assessments indicated 44.6% of livers, 20.0% of viscera, 23.1% of lungs, 22.3% of hearts, 8.2% of heads, and 5.9% of tongues were condemned. Of the cows surveyed, 17.4% carried fetuses at time of harvest. Mean USDA quality grade attributes were skeletal maturity (D⁶⁴), lean maturity (C³⁸), overall maturity (D¹³), and marbling score (Slight⁶⁴). The highest frequency of each USDA quality grade for cows surveyed were USDA Utility. The mean USDA yield grade attributes were preliminary yield grade (2.5), carcass weight (311.5 kg), LM area (65.4 cm²), KPH (1.7%), and USDA yield grade (2.9) for all carcasses surveyed. The National Beef Quality Audit - 2016 is an important addition to the Quality Audit series. Comparisons across years allow for assessment of beef quality improvement. In addition, current results provide guidance for continued educational and research efforts for improving market cow and bull beef quality

Effects of temperature on Zooxanthellae strains in coral species Rhodactis rhodostoma

ABSTRACT Effects of temperature on Zooxanthellae strains in coral species Rhodactis rhodostoma. (May 2014) McKensie Daugherty Department of Biology Texas A&M University Research Advisor: Dr. Duncan MacKenzie Department of Biology Coral reefs are among the most diverse and fragile ecosystems in the ocean. Corals living in lighted zones can have a mutualistic symbiosis with algal dinoflagellates known as Zooxanthellae, specifically the genus Symbiodinium. In the event of stress from the environment (e.g. greater water temperature, acidity, or light permeation), coral can expel Zooxanthellae from their tissues in a process called bleaching. Bleaching is reversible, and it is possible for corals to repopulate with Zooxanthellae strains that are genetically distinct from the original symbiont and thus potentially better suited for the stressing environment. To determine whether this process of bleaching and repopulation could be studied in a small volume captive recirculating system, I took tissues samples from the soft coral Rhodactis rhodostoma held in the Great Aggie Reef, a 135 gallon reef display tank in Texas A&M University’s Biology Department, before and after exposure to increased temperature stress. To determine whether Zooxanthellae were expelled, I used a polymerase chain reaction-based technique to detect the presence of the symbiont-specific ITS1 gene in coral tissue. Whereas more rapid temperature increases were fatal to corals, a gradual increase to 32 degrees was successful in inducing a loss of ITS1 gene expression in surviving corals. These results suggest that this recirculating system may be suitable for further study of coral bleaching and repopulation with Zooxanthellae under controlled conditions