Tortoise and Turtle Extension Lifespan in Related to Branched-Chain and Sulphur Contain Amino Acids: A Review

There are around 350 Turtle/Tortoise living species worldwide
in 13 Families and >90 Genera...

immunological, neurological, and gastrointestinal functions, which are used to construct enzymes, antibodies, immunoglobulins, neurotransmitters, hormones and also an important part of the detoxification process. Methionine, taurine, cysteine, and homocysteine are the sulfur-containing amino acids, while methionine and cysteine both are incorporated into proteins buthomo-cysteine and taurine play vital physiological roles. The body can make cysteine from methionine, for this reason methionine is a dietary essential [6]. The multifunctional role of methionine includes its participation in the synthesis of carnitine, creatine, glutathione, polyamines, nucleic acids, catechol-amines (neurotransmitters), as well as serving as a substrate for protein synthesis.

Some Research Findings and Related Hypothesis-Why Long Life of Tortoises/Turtles?
One of the most accepted hypotheses concerning the longevity of Turtles/Tortoises due to their slow metabolism. Metabolism generally refers to the physical and chemical processes that go on inside a living being in order to keep it alive. Panda [7] informed Tortoise/Turtle is a tranquil nature and diligence, or perhaps its hard shell/ calipash that protects from most physical dangers. It assumes that, having a slow metabolism means that burn energy at a very slow rate, which further opens up other opportunities for longevity. First of all, they can survive for a really long time without food, patient process through which they break down the ingested food and convert it into energy. In addition, Turtles/Tortoises are very slow-moving and relaxed creatures. The longevity of Tortoises can be complete without mentioning the enviable armor that covers almost their entire body [8]. Turtles also realize the importance of a strict vegetarian diet; they usually eat only greens like lettuce, soaked gram (chickpea), carrots, wheat bran, bread, grass and salt at mealtime that staying clear of fat and cholesterol. The oldest known Tortoise on record, Adwaita is one of the longest-living animals in modern times, Adwaita lived to be 255years old. Also, the Aldabra Giant Tortoise had been given to the India Alipore Zoo in 1876 that was assumed to be 150 years old at his death in 2006 [9].

Literature Review
The ability of methionine (Met) restriction to minimize respiratory electron leak contribute prominently to its impact on longevity, In addition, glutamate supplementation extended chronological lifespan [10]. Consistent with the ability of glutamate to extend lifespan, deletion of genes involved in converting glutamate to gamma-aminobutyric acid (GABA) increased replicative lifespan [11] and led to increased conversion of glutamate to α-ketoglutarate and other TCA cycle intermediates, which may be involved in lifespan extension by maintaining mitochondrial respiratory function. Increased levels of amino acids, especially leucine and activate the TOR kinase, which leads to an increased rate of translation [12,13]. The cumulative impact of mitochondrial oxidant stress on the structure and function of mitochondria that can play a key role in the aging process, and progressive mutation or deletion of mitochondrial DNA contributes importantly to aging [14]. Several screens in model organisms have concerned nuclearencoded mitochondrial proteins in the regulation of lifespan with how food availability and metabolism are molecularly coupled to lifespan [15]. Beside, Inhibition of the TOR kinase with Rapamycinor expressing a dominant negative p70-S6 kinase, where a kinase downstream of TOR as a result extended organismal longevity [16,17]. Metabolism of sulfur containing amino acids are the essential for DR-mediated longevity in Drosophila [18], but supplementation of methionine or cysteine failed to extend lifespan in fully fed Drosophila [19,20].
However, supplementing casein and methionine together led to lifespan extension [19]. High-protein diets maximize reproduction and shorten lifespan, and circulating branched-chain amino acids (BCAAs) (leucine, isoleucine, and valine) in particular have been implicated in promoting aging [21,22]. BCAAs are especially potent at activating Target of Rapamycin (TOR) [23], a central cellular pathway of protein sensing and growth. Leucine is the most prevalent of the three BCAAs, which shown to signal the TOR pathway via sestrin2 [24]. In addition, leucine is oxidized to make ATP and carbon-1 is the first carbon released in CO 2 (when NADH is produced). The CO 2 is exhaled and is detected by our Speeding oxidation of leucine may attenuate cellular growth [25]. However, it has been shown that methionine or tryptophan restriction extends lifespan in higher eukaryotes and increased proline or tryptophan levels increase longevity in increases their lifespan, indicating that solely increasing levels of DAF-16 is not sufficient to significantly extend Longevity [26].

Conclusion
In conclusions, a number of observations in a wide range of experimental models have linked metabolism to aging. BCAAs and methionine mostly involve to long life aging factors because leucine is an active complex amino acid and methionine increase growth hormone which increase extension aging. Tortoises and Turtles having a slow metabolism that means they burn energy at a very slow rate as a result further opens up other opportunities for longevity.

Conflict of Interest
The authors declare no conflicts of interest.