Parakaryon

A tiny living thing was found deep in the sea.

It lives near hot vents in the dark ocean. Scientists found it on a small sea worm. This tiny thing is very special. It is not like any other living thing we know.

It has parts of two different groups of life. Some parts are like one group. Other parts are like a different group. This makes it very unique.

We have only found one of them so far. Because there is only one, we know very little. Scientists want to find more to learn more. It is a big mystery of the deep sea.

Scientists found a very strange tiny living thing in the deep sea.

They found it at Myojin Knoll in the Pacific Ocean. It lived on the hair of a scale worm. This organism is called Parakaryon myojinensis. It is very special because it is unique. Most life fits into two groups. These are prokaryotes and eukaryotes.

This tiny life has parts of both groups. It has a nucleus, which is a center for the cell. It also has endosymbionts. These are smaller living things that live inside a larger host. But it is different from both groups in other ways. For example, it does not have a cytoskeleton. A cytoskeleton is a frame that helps a cell keep its shape.

We have only found one specimen so far. This makes it hard to study. Scientists want to find more to learn its secrets. They want to see its DNA. This would help them know where it fits in the tree of life.

Scientists found a very strange living thing in the deep sea. This tiny creature is called Parakaryon myojinensis. It is a single-celled organism that does not fit into normal groups. Most life belongs to either prokaryotes or eukaryotes. This specimen has parts of both types. It also has parts that are different from both. Because it is so unique, it is the only species in its genus.

This organism works in a very unusual way. It has a nucleus, which is a central part of a cell. This nucleus has only one layer of membrane. Most eukaryotes have two layers. It also has endosymbionts. These are smaller living things that live inside a larger host. The ribosomes, or small parts that make proteins, are found in both the cytoplasm and the nucleus. However, it lacks a cytoskeleton. A cytoskeleton is a frame that helps a cell keep its shape.

Researchers first described this species in 2012. A group of scientists led by Yamaguchi found the specimen. They found it at a place called Myojin Knoll. This is deep in the Pacific Ocean. It is located near Aogashima island. The sample came from the bristle of a scale worm. The name comes from Greek words meaning "next to the nucleus."

Finding this life was a big event. The researchers looked at the parts of the cell very closely. They saw one large helix with a volume of 2.3 cubic micrometers. They also saw two smaller pieces. These smaller pieces had volumes of 0.2 and 0.1 cubic micrometers. In 2016, the same team found helical bacteria nearby. They called these "Myojin spiral bacteria."

This discovery helps us think about how life grows. Scientists are not sure if it is a prokaryote or a eukaryote. They only have one specimen to study right now. They need more samples to look at its DNA. Nick Lane wrote about this in a 2015 book. He thought it might show how complex life begins through symbiogenesis. This is when different living things join together to live as one.

Parakaryon myojinensis is a highly unusual single-celled organism. It belongs to the genus Parakaryon and the domain Parakarya. This species is unique because it does not fit easily into standard biological groups. Most life is divided into prokaryotes or eukaryotes. However, this organism shows features of both groups. It also possesses traits that are different from both. Scientists have only ever found one single specimen of this organism. This makes it a monotypic genus, meaning it is the only species in its group.

The structure of P. myojinensis is a complex puzzle for biologists. It possesses a nucleus, which is a central part of a cell. In most eukaryotes, the nucleus has two layers of membrane. In P. myojinensis, the nuclear membrane has only one layer. It also has nuclear pores, which are openings in the membrane. The ribosomes, or protein-making parts, are found in both the cytoplasm and the nucleus. This is different from most other cells. It also contains endosymbionts, which are smaller organisms living inside a host.

Despite these complex parts, the organism lacks several standard features. It does not have a cytoskeleton, which is a frame that provides cell shape. It also lacks an endoplasmic reticulum and a Golgi apparatus. These are parts used by eukaryotes to process materials. Additionally, it does not have mitochondria, which usually provide energy to eukaryotic cells. Instead, its chromosomes have a filamentous structure. This differs from the linear chromosomes found in eukaryotes or the variable structures in prokaryotes.

Researchers first described this species in 2012. The discovery was made by a team led by Yamaguchi. They found the specimen at Myojin Knoll in the Pacific Ocean. This location is near Aogashima island, southeast of the Japanese archipelago. The sample was taken from the bristle of a scale worm. The worm lived near hydrothermal vents on the ocean floor. The name Parakaryon comes from Greek words meaning "beside" or "near" the nucleus. The specific name myojinensis refers to the Myojin location.

Scientists have debated whether this organism is a real species or an artifact. An artifact is something created by the way a sample is prepared. Yamaguchi and his team proposed three reasons why it is a genuine species. First, they noted it is unlikely that many different bacteria attacked a host at once. They observed one large helix with a volume of 2.3 μm³. They also saw two smaller pieces with volumes of 0.2 μm³ and 0.1 μm³.

Second, the researchers observed that the cells looked healthy. The cytoplasms of the host and the endosymbionts showed orderly structures. This suggests that no digestion had occurred between them. Third, they argued that if this were a predator-host interaction, predator populations would need to be very dense. In 2016, the team found "Myojin spiral bacteria" on polychaetes in the same area. In 2020, other studies showed bacteria containing intracellular bacteria in the same region.

The discovery has major implications for evolutionary biology. It is unclear if P. myojinensis is a prokaryote or a eukaryote. Because only one specimen exists, scientists cannot perform DNA sequencing. They need more samples to understand its place in the tree of life. In 2015, biochemist Nick Lane hypothesized about its significance. He suggested it could be an example of symbiogenesis outside of eukaryotes. Symbiogenesis is when different organisms join to form a new, complex life form. This could reveal how complex life began on Earth.