| 1. |
- Noonin, Chadanat, et al.
(författare)
-
Crayfish hematopoietic tissue as a model for stem cell development in arthropods
- 2012
-
Konferensbidrag (refereegranskat)abstract
- Arthropods, are suitable model animals to study the regulation of blood cell synthesis and differentiation of the innate immune system, since they lack the lymphocytes, and oxygen-carrying erythrocytes. In contrast to most insects, many crustaceans have a long life span and need to continuously synthesize blood cells. Crayfish hematopoiesis takes place in the hematopoietic tissue (HPT). The HPT of Pacifastacus leniusculus provides a simple model to study hematopoiesis because the tissue can be isolated and the proliferation of stem cells and their differentiation can be studied both in vivo and in vitro. This tissue was earlier shown to be localized at the dorsal part of stomach. Here, we show that the HPT extends towards the anterior part the animal and link to the brain. Staining of HPT sections revealed that the most anterior of the tissue close to the brain contains higher percentage of cells with loose chromatin, whereas most of the cells in the posterior part have dark nuclear staining with condense chormatin. BrdU incorporation and immunostaining for phospho-histone H3 indicates that the actively proliferating cells occupy the anterior part of the tissue especially in the area close to the brain, proposed stem cell center (SCC). In contrast the more differentiated cells reside in the posterior part. Injection of LPS, which induced blood loss mimicking a bacterial infection, stimulated HPT cell proliferation especially in the anterior part of the tissue. High ROS level was found close to proliferating SCC and the brain, and laminarin-induced hemocyte loss caused induction of ROS level in SCC. This indicates the involvement of ROS in crayfish hematopoiesis. Isolated cells from SCC actively divide and form cell clusters whereas the cells from the remaining HPT from monolayer in in vitro culture. Collagen-I-matrix gel provided an appropriate environment for HPT cell culture and exhibited a suitable system to study HPT cell proliferation and differentiation indicating by induction of hemocyte marker transcripts. Being easily isolated and studied both in vitro and in vivo on stem cell proliferation as well as differentiation into mature hemocytes suggests that crayfish HPT provides an alternative simple model system to study hematopoiesis in arthropods. Moreover, the discovery of the astakine cytokines and antiapoptotic factor CHF offers an opportunity to explore the regulation of invertebrate hematopoiesis and its connection to the central nervous system as well as give new information on the evolution of different blood cell lineages.
|
|
| 2. |
|
|
| 3. |
- Noonin, Chadanat, et al.
(författare)
-
Invertebrate hematopoiesis : an anterior proliferation centre as a link between the hematopoietic tissue and the brain
- 2012
-
Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 21:17, s. 3173-3186
-
Tidskriftsartikel (refereegranskat)abstract
- During evolution, the innate and adaptive immune systems developed to protect organisms from nonself substances. The innate immune system is phylogenetically more ancient and is present in most multicellular organisms, whereas adaptive responses are restricted to vertebrates. Arthropods, lack the blood cells of the lymphoid lineage, and oxygen-carrying erythrocytes, making them suitable model animals to study the regulation of the blood cells of the innate immune system. Many crustaceans have a long life span and need to continuously synthesize blood cells, in contrast to many insects. The hematopoietic tissue (HPT) of Pacifastacus leniusculus provides a simple model to study hematopoiesis because the tissue can be isolated and the proliferation of stem cells and their differentiation can be studied both in vivo and in vitro. Here we demonstrate new findings of a physical link between the HPT and the brain. Actively proliferating cells were localized to an anterior proliferation centre (APC) in the anterior part of the tissue near the area linking the HPT to the brain, whereas more differentiated cells were detected in the posterior part. The central areas of HPT expand in response to lipopolysaccharide-induced blood loss. Cells isolated from the APC divide rapidly and form cell clusters in vitro; conversely, the cells from the remaining HPT form monolayers, and they can be induced to differentiate in vitro. Our findings offer an opportunity to learn more about invertebrate hematopoiesis and its connection to the central nervous system and thereby to obtain new information about the evolution of different blood and nerve cell lineages.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Wu, Chenglin, et al.
(författare)
-
An insect TEP in a crustacean is specific for cuticular tissues and involved in intestinal defense
- 2012
-
Ingår i: Insect Biochemistry and Molecular Biology. - : Elsevier BV. - 0965-1748 .- 1879-0240. ; 42:2, s. 71-80
-
Tidskriftsartikel (refereegranskat)abstract
- In an attempt to identify genes encoding thioester-containing proteins in the freshwater crayfish, Pacifastacus leniusculus, three different cDNAs were found. A phylogenetic analysis of these proteins indicates that they can be classified into two subfamilies: two alpha-2-macroglobulins (Pl-A2M1, Pl-A2M2) showing a close similarity to shrimp A2M, and one insect TEP-like protein (Pl-TEP). This is the first report of an insect TEP-like protein in a crustacean. Crayfish Pl-A2M1, Pl-A2M2 and Pl-TEP cDNAs encode proteins with 1480, 1586 or 1507 amino acids, respectively. Pl-A2M1, Pl-A2M2 and Pl-TEP have the basic domain structure and functionally important residues for each molecule, and their mRNA was detected in different parts of the body, suggesting that they may have different functions. Pl-A2M1 was mainly expressed in hemocytes and Pl-A2M2 was highly expressed in heart and nerve, while Pl-TEP was exclusively expressed in cuticular tissues such as gill and intestine. RNA interference of Pl-TEP in vivo resulted in that these animals were slightly less resistant when fed with the bacterium, Pseudomonas libanensis/gessardii. Furthermore, when TEP activity was blocked using methylamine followed by bacterial feeding, the animals were killed to a higher extent compared to a control group. Taken together, this indicates that Pl-TEP and/or Pl-A2M1, Pl-A2M2 may be important for the immune defense in crayfish intestine and function as a pattern recognition protein in crayfish cuticular tissues.
|
|
