Molecular and biochemical responses to sand-dwelling in the three-spot wrasse (Halichoeres trimaculatus)

The three-spot wrasse (Halichoeres trimaculatus) is distributed in and around the coral reefs and shallow rocky areas in the tropical and subtropical Indo-Pacific regions. This species displays a distinct diurnal behavior, burrowing under the sand at dusk and emerging out of the sand at dawn, which appears to be synchronized to the photoperiod. In this thesis, the hypothesis tested was that this unique life-style subjected the animal to daily hypoxia exposure while under the sand at night. The measurements of oxygen concentration in the sand around the fish at night confirmed a complete lack of oxygen. The study had three specific objectives: i) obtain a tissue-specific temporal profile of the hypoxia-related molecular and biochemical responses in wrasse over a 24 h diurnal cycle, ii) determine the responses that were unique to sand dwelling and iii) determine if the responses seen at night in the sand are similar to an anoxic response in this species. Wrasse were maintained in a flow-through seawater aquaria (29 ±1°C), with sand at the bottom for the fish to hide, and kept under natural photoperiod. The fish were sampled at 10:00, 14:00, 18:00, 21:00, 24:00, 3:00, and 6:00 clock time and plasma and tissue (brain, liver, gill, heart and muscle) were collected to determine the molecular and biochemical responses over a 24 h period. Fish were also sampled from aquaria without sand at night to determine the responses that were specific to hiding in the sand, while fish exposed to nitrogen gas bubbling for 6 and 12 h served as the anoxic group. A partial cDNA sequence of the hypoxia-inducible factor (HIF)-1α and neuroglobin (two genes that are hypoxia-responsive) were cloned and sequenced from the liver and brain, respectively, and their expression was determined using real-time quantitative PCR. HIF-1α mRNA abundance was higher in the brain compared to the liver and the gills, while a clear pattern of diurnal change in tissue HIF-1α and brain neuroglobin gene expressions was not observed at night relative to the fish during the day. However, wrasse brain showed a significant reduction in glycogen content at night under the sand and this corresponded with a higher hexokinase activity and increased glucose level suggesting enhanced glycolytic capacity. The plasma glucose and lactate levels were significantly lower at night, while in sand, relative to the day. The lower plasma glucose at night corresponded with a significant drop in liver gluconeogenic capacity (reduction in phosphoenolpyruvate carboxykinase, a key gluconeogenic enzyme, activity), while the lower lactate levels support a lack of activity along with the absence of glycogen breakdown in the muscle. Overall, there was a reduction in the metabolic capacity in the gills, heart, liver and muscle, but not the brain, supporting a tissue-specific metabolic reorganization as an adaptive strategy to cope with sand-dwelling in the wrasse. The molecular and biochemical responses seen in the wrasse at night in the sand was dissimilar to that seen in fish exposed to anoxia, leading to the conclusion that this species is not experiencing a complete lack of oxygen while under the sand. Also, the lack of muscle movement associated with sand dwelling at night limits anaerobic glycolysis for energy production, thereby eliminating lactate accumulation that was evident in fish exposed to anoxia. Taken together, wrasse showed a tissue-specific difference in metabolic capacity at night while hiding under the sand. While the mechanism involved in this tissue-specific energy repartitioning at night is unclear, one hypothesis involves selective increase in blood flow to the brain, while limiting peripheral circulation, as a means to maintain oxygen and glucose delivery to this critical tissue while the fish is hiding under the sand. The higher metabolic capacity of the brain, but not other tissues, at night under the sand suggests that maintaining the brain function is essential for the diurnal life-style in this animal

Models and Application of Firefighting Vulnerability

AbstractGeographic information systems (GIS) have been applied to analyze the efficiency and effectiveness of public facility services such as fire stations, police stations and day-care centers. Regardless of the scientific contribution of such an approach, there are numerous limitations to follow the rules or optimized suggestions due to high land price and other societal factors. In the present study, we narrowed the scope to firefighting services: how to decrease firefighting dismissals and help firefighters recognize the situation of fire events before arriving at the fire scenes. The absolute time from the fire station to the fire scene was considered to be the Mobility Kill Zone. Narrow roads and illegal parking were classified as the Operation Kill Zone. Areas with identified hazardous commodities and toxic substances were classified as the Identified Hazardous Zone. The areas cluttered with fire safety management objects were classified as the Fire Vulnerability Zone. Four models were suggested in our previous research and in the present study, we elaborated upon the models and examined new information technology (IT) to implement the models in rural and urban areas

Mouse Genetic Models Reveal Surprising Functions of IκB Kinase Alpha in Skin Development and Skin Carcinogenesis

Gene knockout studies unexpectedly reveal a pivotal role for IκB kinase alpha (IKKα) in mouse embryonic skin development. Skin carcinogenesis experiments show that Ikkα heterozygous mice are highly susceptible to chemical carcinogen or ultraviolet B light (UVB) induced benign and malignant skin tumors in comparison to wild-type mice. IKKα deletion mediated by keratin 5 (K5).Cre or K15.Cre in keratinocytes induces epidermal hyperplasia and spontaneous skin squamous cell carcinomas (SCCs) in Ikkα floxed mice. On the other hand, transgenic mice overexpressing IKKα in the epidermis, under the control of a truncated loricrin promoter or K5 promoter, develop normal skin and show no defects in the formation of the epidermis and other epithelial organs, and the transgenic IKKα represses chemical carcinogen or UVB induced skin carcinogenesis. Moreover, IKKα deletion mediated by a mutation, which generates a stop codon in the Ikkα gene, has been reported in a human autosomal recessive lethal syndrome. Downregulated IKKα and Ikkα mutations and deletions are found in human skin SCCs. The collective evidence not only highlights the importance of IKKα in skin development, maintaining skin homeostasis, and preventing skin carcinogenesis, but also demonstrates that mouse models are extremely valuable tools for revealing the mechanisms underlying these biological events, leading our studies from bench side to bedside

Stress and Microstructure Evolution in Mo Thin Films without or with Cover Layers during Thermal-Cycling

The intrinsic stress behavior and microstructure evolution of Molybdenum thin films were investigated to evaluate their applicability as a metallization in high temperature microelectronic devices. For this purpose, 100 nm thick Mo films were sputter-deposited without or with an AlN or SiO2 cover layer on thermally oxidized Si substrates. The samples were subjected to thermal cycling up to 900 °C in ultrahigh vacuum; meanwhile, the in-situ stress behavior was monitored by a laser based Multi-beam Optical Sensor (MOS) system. After preannealing at 900 °C for 24 h, the uncovered films showed a high residual stress at room temperature and a plastic behavior at high temperatures, while the covered Mo films showed an almost entirely elastic deformation during the thermal cycling between room temperature and 900 °C with hardly any plastic deformation, and a constant stress value during isothermal annealing without a notable creep. Furthermore, after thermal cycling, the Mo films without as well as with a cover layer showed low electrical resistivity (≤10 μΩ·cm)

Regulation of Apoptosis during Environmental Skin Tumor Initiation

Skin cancer is more prevalent than any other cancer in the United States. Nonmelanoma skin cancers are the more common forms of skin cancer that affect individuals. The development of squamous cell carcinoma, the second most common type of skin cancer, can be stimulated by exposure of environmental carcinogens, such as chemical toxicants or UVB. It is developed by three distinct stages: initiation, promotion, and progression. During the initiation, the fate of DNA-damaged skin cells is determined by the homeostatic regulation of pro-apoptotic and antiapoptotic signaling pathways. The imbalance or disruption of either signaling will lead to the survival of initiated cells, resulting in the development of skin cancer. In this chapter, we will discuss signaling pathways that regulate apoptosis and the impact of their dysfunction during skin tumor initiation

Regulation of Apoptosis during Environmental Skin Tumor Initiation

Skin cancer is more prevalent than any other cancer in the United States. Nonmelanoma skin cancers are the more common forms of skin cancer that affect individuals. The development of squamous cell carcinoma, the second most common type of skin cancer, can be stimulated by exposure of environmental carcinogens, such as chemical toxicants or UVB. It is developed by three distinct stages: initiation, promotion, and progression. During the initiation, the fate of DNA-damaged skin cells is determined by the homeostatic regulation of pro-apoptotic and antiapoptotic signaling pathways. The imbalance or disruption of either signaling will lead to the survival of initiated cells, resulting in the development of skin cancer. In this chapter, we will discuss signaling pathways that regulate apoptosis and the impact of their dysfunction during skin tumor initiation

MicroRNAs down-regulate homologous recombination in the G1 phase of cycling cells to maintain genomic stability

Homologous recombination (HR)-mediated repair of DNA double-strand break (DSB)s is restricted to the post-replicative phases of the cell cycle. Initiation of HR in the G1 phase blocks non-homologous end joining (NHEJ) impairing DSB repair. Completion of HR in G1 cells can lead to the loss-of-heterozygosity (LOH), which is potentially carcinogenic. We conducted a gain-of-function screen to identify miRNAs that regulate HR-mediated DSB repair, and of these miRNAs, miR-1255b, miR-148b*, and miR-193b* specifically suppress the HR-pathway in the G1 phase. These miRNAs target the transcripts of HR factors, BRCA1, BRCA2, and RAD51, and inhibiting miR-1255b, miR-148b*, and miR-193b* increases expression of BRCA1/BRCA2/RAD51 specifically in the G1-phase leading to impaired DSB repair. Depletion of CtIP, a BRCA1-associated DNA end resection protein, rescues this phenotype. Furthermore, deletion of miR-1255b, miR-148b*, and miR-193b* in independent cohorts of ovarian tumors correlates with significant increase in LOH events/chromosomal aberrations and BRCA1 expression. DOI: http://dx.doi.org/10.7554/eLife.02445.00

Exercise Training Attenuates Ovariectomy-Induced Alterations in Skeletal Muscle Remodeling, Apoptotic Signaling, and Atrophy Signaling in Rat Skeletal Muscle

Purpose The effects of aerobic exercise training on soleus muscle morphology, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in ovariectomized rat skeletal muscle were investigated. Methods Female Sprague-Dawley rats were divided into control (CON), ovariectomy (OVX), and ovariectomy plus exercise (OVX+EX) groups. After ovarian excision, exercise training was performed using a rat treadmill at 20 m/min, 50 min/day, 5 days/week for 12 weeks. Protein levels of mitochondria-mediated apoptotic signaling and atrophy/hypertrophy signaling in the skeletal muscle (soleus) were examined through western immunoblot analysis. Results The number of myocytes and myocyte cross-sectional area (CSA) were increased and the extramyocyte space was decreased in the OVX group compared to those in the CON group. However, aerobic exercise training significantly increased myocyte CSA and decreased extramyocyte space in the OVX+EX group compared to those in the OVX group. The protein levels of proapoptotic signaling and muscle atrophy signaling were significantly increased, whereas the protein levels of muscle hypertrophy signaling were significantly decreased in the OVX group compared to that in the CON group. Aerobic exercise training significantly decreased the protein levels of proapoptotic signaling and increased the protein level of antiapoptotic protein in the OVX+EX group compared to that in the OVX group. Aerobic exercise training significantly increased the protein levels of hypertrophy signaling and decreased protein levels of atrophy signaling in the OVX+EX group compared to those in the OVX group. Conclusions Treadmill exercise improved estrogen deficiency-induced impairment in skeletal muscle remodeling, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in skeletal muscle

Regulation of Apoptosis during Environmental Skin Tumor Initiation

Skin cancer is more prevalent than any other cancer in the United States. Non-melanoma skin cancers are the more common forms of skin cancer that affect individuals. The development of squamous cell carcinoma, the second most common type of skin cancer, can be stimulated by exposure of environmental carcinogens, such as chemical toxicants or UVB. It is developed by three distinct stages: initiation, promotion, and progression. During the initiation, the fate of DNA-damaged skin cells is determined by the homeostatic regulation of pro-apoptotic and anti-apoptotic signaling pathways. The imbalance or disruption of either signaling will lead to the survival of initiated cells, resulting in the development of skin cancer. In this chapter, we will discuss signaling pathways that regulate apoptosis and the impact of their dysfunction during skin tumor initiation