In general biology or reproductive physiology the term nurse cell is defined as a cell which provides food, helps other cells and provides stability to their neighboring cells. The term nurse cell is used in several unrelated ways in different scientific fields.

Human physiology

Nurse cells are specialized

macrophage Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cel ...

s residing in the

bone marrow Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...

that assist in the development of

red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s. They absorb the nuclei of immature red blood cells and may provide

growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for regu ...

s to help the red blood cells mature. In the bone marrow, immature red blood cells (

erythroblast A nucleated red blood cell (NRBC), also known by several other names, is a red blood cell that contains a cell nucleus. Almost all vertebrate organisms have hemoglobin-containing cells in their blood, and with the exception of mammals, all of t ...

s) can be seen grouped in a cluster around a nurse cell. The epithelial cell found in the cortex of the

thymus The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...

is also called a "nurse cell." These cells produce Thymic hormones that cause T lymphocytes to mature and differentiate.

Parasitology

In parasitology, a nurse cell is an infected cell in the disease

trichinosis Trichinosis, also known as trichinellosis, is a parasitic disease caused by roundworms of the ''Trichinella'' type. During the initial infection, invasion of the intestines can result in diarrhea, abdominal pain, and vomiting. Migration of larv ...

discovered by

Dickson Despommier Dickson D. Despommier (June 5, 1940) is an emeritus professor of microbiology and Public Health at Columbia University. From 1971 to 2009, he conducted research on intracellular parasitism and taught courses on parasitic diseases, medical ecolo ...

. A trichinella

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

enters a

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

and develops there, probably as a way of concealing itself from the

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...

. The parasite has evolved a way of stimulating

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

development around the cell, in order to receive the nutrients it needs. In trichinosis, nurse cells are invariably

skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

cells; these are the only type of cell that can support the

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

Mycology

In mycology, a nurse cell is any

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

that supplies food material to

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

that have detached from the

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

; used especially in reference to taxa from the family

Sclerodermataceae The Sclerodermataceae are a family of fungi in the order Boletales, containing several genera of unusual fungi that little resemble boletes. Taxa, which include species commonly known as the ‘hard-skinned puffballs’, ‘ earthballs’, or 'ea ...

Cell biology

Ribonucleoprotein particles in the Drosophila egg chamber

In respect to

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s, nurse cells are polytenic germline cells that contribute to the development of the

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...

, producing multiple nuclei. In fruit flies ''(

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

),'' nurse cells surround the developing oocyte and synthesize proteins and RNAs that are to be deposited in it. Nurse cells are highly polyploid (up to 8000C). They dump their

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

containing RNAs and proteins into the oocyte via ring canals. Due to their high metabolic activity, nurse cells likely experience the DNA damaging effect of oxidative free radicals produced as a byproduct of this metabolism. This damaging effect would otherwise befall the DNA of the egg cells if they were responsible for their own synthesis. The many genome copies in each nurse cell may provide redundancy of genetic information that would allow the nurse cell to carry out its provisioning function even in the face of considerable oxidative DNA damage.Bernstein, C (1998). Sex as a response to oxidative DNA damage. Chapter 4, see pages 112-113. In “DNA and Free Radicals: Techniques, Mecchanisms @ Applications” (editors: Okezie I Aruoma, Barry Halliwell). OICA International (publisher), Saint Lucia and London

References

{{DEFAULTSORT:Nurse Cell Parasitology Parasites

Human physiology

Parasitology

Mycology

Cell biology

See also

References