Estuarine crustaceans are often exposed to low dissolved O2 (hypoxia) accompanied by elevated CO2 (hypercapnia), which lowers water pH. Acclimatory responses to hypoxia have been widely characterized; responses to hypercapnia in combination with hypoxia (hypercapnic hypoxia) are less well known. Here we used oligonucleotide microarrays to characterize changes in global gene expression in the hepatopancreas of Pacific whiteleg shrimp, Litopenaeus vannamei, exposed to hypoxia or hypercapnic hypoxia for 4 or 24 h, compared with time-matched animals held in air-saturated water (normoxia). Unigenes whose expressions were significantly impacted by treatment and/or time were used to build artificial neural networks (ANNs) to identify genes with the greatest sensitivity in pairwise discriminations between treatments at each time point and between times for each treatment. ANN gene sets that discriminated hypoxia or hypercapnic hypoxia from normoxia shared functions of translation, mitochondrial energetics, and cellular defense. GO terms protein modification/phosphorylation/cellular protein metabolism and RNA processing/apoptosis/cell cycling occurred at highest frequency in discriminating hypercapnic hypoxia from hypoxia at 4 and 24 h, respectively. For 75.4% of the annotated ANN genes, exposure to hypercapnic hypoxia for 24 h reduced or reversed the transcriptional response to hypoxia alone. These results suggest that high CO2/low pH may interfere with transcriptionally based acclimation to hypoxia or elicit physiological or biochemical responses that relieve internal hypoxia. Whether these data reflect resilience or sensitivity of L. vannamei in the face of expanding hypoxic zones and rising levels of atmospheric CO2 may be important to understanding the survival of this and other estuarine species.

CKD and its complications are associated with substantial morbidity and mortality. Studies have highlighted significant deficiencies in resident knowledge and awareness of CKD and its complications. There is a need to improve CKD education through medical school and residency. There is also a need to provide alternatives to traditional teaching methods to meet the challenges of learning in the context of work-hour restrictions and increasing workload among residents and fellows. Internet-based learning resources offer various educational tools, including websites, kidney blogs, online modules, and smartphone applications, which could potentially and efficiently advance CKD knowledge among medical trainees. In this review, we describe several online resources for CKD education that could be useful for medical students, residents, and fellows. Increased awareness of these tools and their utilization may significantly influence and hopefully improve the recognition and management of patients with CKD. Future studies may help evaluate the effectiveness of these online learning methods and their effect on CKD patient outcomes. In addition, in light of increased concern about nephrology workforce issues, the potential for these online tools to augment interest in nephrology careers should be investigated.