Heat stress (HS) results from exposure to a temperature condition beyond the optimum range of an organism. Following heat stress, cells exhibit a heat-shock response (HSR), which is a highly-conserved and prominent pathway with a series of stress-inducible gene expression, to increase thermal tolerance and facilitate cellular recovery. Previous studies demonstrated that the response caused by exposure to heat stress is similar in bacteria, plants, and mammals. Because HSR is conserved across species and there is a growing interest in how stress responses are integrated to affect lifespan, disease pathology, the technique is widely used to combine with the C. elegans community. C. elegans has great utility as a simple model system to study aging as well as other complex human diseases, besides, heat shock is inexpensive and requires little additional equipment. Therefore, C. elegans model is a great choice to study the HS and HSR.
C. elegans can grow and reproduce at temperatures from 12°-26°C. They are most fecund at temperatures near 16°C, and cannot sustainable at 27°C. Similar to other organisms, C. elegans is exquisitely sensitive to maintenance temperature, even slight increases of temperature can elicit the response of heat-shock proteins (HSPs), a family of proteins induced in response to stressful conditions. Over the past decades, the heat-shock response has been well studied in C. elegans, revealing three main neuroendocrine signaling pathways, including the nuclear hormone receptor (NR) pathway, the transforming growth factor-b (TGF-b) pathway, and the IGF/insulin-like signaling (ILS) pathway. Among them, ILS pathway is the most thoroughly studied, which is implicated in HSPs, HSF-1, and may be useful for understanding cancer, aging, and age-related neurodegenerative diseases in humans.
There are many variations in heat-shock protocols published depending on in which lab the protocol was developed and the specific lab standard. The differences include exposure temperatures, times, and differently aged worms. Although the protocols are essential references, the lack of standardization makes it difficult to compare results across laboratories, and a quandary generated when conducting the experiments in one's own laboratory. CD BioSciences focuses on the stress model system and has developed validated protocols on dealing with the problems, within uniform standardization, optimal procedure and operation under strict control.
Here we offer two kinds of heat-shock protocols, including basic 37°C heat-shock protocol, and hormetic 34°C mild heat shock followed by 37°C acute heat-shock protocol. And the main consideration for heat stress experiments is shown below.
|Main considerations for HS experiments|
|Temperature||37°C (35°C is most often used for acute heat stress)|
|Liquid culturing||An ideal option for severe heat stress where the time of exposure is less than 1 hour. ( an option for large-scale screening)|
|Duration of Heat Shock||A 60-minute mild heat stress produced no detectable hormetic response while 90 minutes can elicit a good response|
|Age/Developmental Stage||Resistance to heat shock is highest in L1/L2 larvae and lowest in L4, and later L4 worms survive better than earlier L4 worms|
|When to score survival||12-14 hours post-heat shock (maintained in a 20°C incubator)|
CD BioSciences offers a broad and integrated portfolio of laboratory and manufacturing C. elegans environmental stress responses research services, including heat-shock service, which is a widely used method within the C. elegans community to study the impact of stress on physiology, behavior, fecundity and survival. We focus on the stress model system to help our customers to insight into the genetic and molecular mechanisms underlying stress-associated human diseases and their impact on lifespan. If you are interested in our service, please don't hesitate to contact us.
* For research use only.