Methionine is a non-polar amino acid and is one of the only two amino acids to contain a sulphur group. However, unlike cysteine, it cannot form sulphur bridges (a covalent bond between two sulphur atoms, used to stabilise the 3D structure of some proteins) as there is no hydrogen attached to the sulphur. Methionine is an intermediate in the synthesis of compounds such as lecithin and taurine, along with many others, mostly phospholipids.
A derivative of methionine, N-formylmethionine, is always used as the initial amino acid in translation in bacteria and methionine is always found in the beginning of eukaryotic proteins although is often removed during post-translational modification. The reason for both of these is that methionine is coded for by the codon AUG, the same as the start codon for translation.
Methionine is an essential amino acid in humans although other organisms (including other mammals) can synthesise methionine from aspartic acid and cysteine. This is a multi-step process requiring both ATP and NADPH.
“I was learning about regeneration. We were injecting axolotls and seeing how they removed their arms. We looked at stem cells that they wired to beat like a human heart. They are finding ways to do this. I was fascinated!”—Emma Stone, discussing how she learned about stem cells while filming Amazing Spider-Man, as if we needed another reason to love her. (via jtotheizzoe)
Pastor-turned-principal Marie Carrier says that the her first through eighth-grade students learn at their own pace from Christian workbooks. The beginning science text explains “what God made” on each of the six days of creation. Evolution is not taught. Carrier said, “We try to stay away from all those things that might confuse our children.”
One textbook, Biology 1099, reads, “Are dinosaurs alive today? Scientists are becoming more convinced of their existence. Have you heard of the ‘Loch Ness Monster’ in Scotland? ‘Nessie’ for short has been recorded on sonar from a small submarine, described by eyewitnesses, and photographed by others. Nessie appears to be a plesiosaur.”
As part of a push from Louisiana’s governor to move millions of tax dollars to cover tuition for private schools, thousands of schoolchildren will receive publicly funded vouchers to attend private schools, including small bible-based church schools.
Carrier hopes to secure enrollment of 135 voucher students for the 2012-2013 school year. According to the website Salon, the school currently has just 38 students.
Whether this gambit will help move Louisiana from the bottom of math and science rankings in the country is unclear. A 2011 study of how well primary education prepares students for engineering careers had Louisiana third from the bottom, with only West Virginia and Mississippi performing worse.
Size: Head-body length: 9 – 11 cm Tail length: 12 – 14 cm
Weight: 30 g
Description: Described as a new species in 2000, the tiny Madame Berthe’s Mouse Lemur is believed to be the world’s smallest extant primate. This species has extremely large, forward-facing eyes, which have a shiny layer behind the retina that reflects light back through the eye, dramatically improving night-vision. The fur is reddish-brown on the dorsal surface with a darker stripe running down the midline of the back from the shoulders to the tail while, in contrast, the fur on the ventral surface is creamy or pale grey. The head of this species is distinctively marked with a dull white patch above the nose and cinnamon rings around the eyes. Like other mouse lemurs, Madame Berthe’s Mouse Lemur has a long tail, relatively large ears and furless/bare digits.
Habitat and Distribution: Madame Berthe’s Mouse Lemur inhabits lowland, dry, deciduous forest between sea-level and elevations of 150 metres. Endemic to Madagascar, this species is restricted to the Menabe region in the south-west of the island, south of Tsiribihina River, in an area that probably covers no more than 900 square kilometres, where it co-occurs with the much wider distributed Grey Mouse Lemur.
Biology and Ecology: Given the relatively recent discovery of this particular species limited information pertaining to its biology and ecology is currently available. A nocturnal, solitary forager, Madame Berthe’s Mouse Lemur is exceptionally agile when moving through the trees and low-level vegetation, searching for insects, fruit and small reptiles such as geckos and chameleons. While the diet of this species is extremely varied, its major food source is the sugary secretion, or “honeydew”, produced by the larvae of the insect species, Flatida coccinea. At dawn, Madame Berthe’s Mouse LEmur conceals itself amongst vegetation, often in a tangle of vines, where it may be accompanied by other individuals of the same species. Interestingly, during the cooler, dry winter months, Madame Berthe’s Mouse Lemur undergoes a daily period of torpor, lowering its metabolic rate for a few hours, which causes its body temperature to drop to ambient levels, thereby conserving water and energy. This species is heavily preyed upon by owls, civets, mongooses, snakes and even other lemurs. Mating occurs in November, with the young born, after a gestation period of around two months in January.
Status and Threats: Madame Berthe’s Mouse Lemur is classified as Endangered under the IUCN Redlist and listed on Appendix I of CITES. Like many Madagascan species, Madame Berthe’s Mouse Lemur is threatened by habitat loss due to illegal logging and slash-and-burn agriculture. With its highly restricted range and a global population estimated to be no more than 8,000 mature individuals, this species faces an uncertain future.