Limits...
Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney.

Cueto JA, Rodriguez C, Vega IA, Castro-Vazquez A - PLoS ONE (2015)

Bottom Line: Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes.Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads.A role for the kidney as an immune barrier is proposed for this snail.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina; Instituto de Histología y Embriología "Dr. Mario H. Burgos", Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina.

ABSTRACT
Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail.

Show MeSH

Related in: MedlinePlus

Details of circulating hemocytes (TEM).(A) Cytoplasm of a hyalinocyte showing numerous mitochondria and some RER and SER profiles. (B) Detail of another hyalinocyte showing an extended RER cisterna, SER vesicles and a membrane-unbound zone with presumptive glycogen granules. (C) Cytoplasm of a hyalinocyte showing numerous SER vesicles, as well as a few L granules and mitochondria. (D) Cytoplasm of a granulocyte showing numerous R granules around a Golgi complex. Abbreviations: gly, presumptive glycogen granules; other abbreviations as in Fig 3. Scale bars represent 1 μm.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4404100&req=5

pone.0123964.g004: Details of circulating hemocytes (TEM).(A) Cytoplasm of a hyalinocyte showing numerous mitochondria and some RER and SER profiles. (B) Detail of another hyalinocyte showing an extended RER cisterna, SER vesicles and a membrane-unbound zone with presumptive glycogen granules. (C) Cytoplasm of a hyalinocyte showing numerous SER vesicles, as well as a few L granules and mitochondria. (D) Cytoplasm of a granulocyte showing numerous R granules around a Golgi complex. Abbreviations: gly, presumptive glycogen granules; other abbreviations as in Fig 3. Scale bars represent 1 μm.

Mentions: A well developed smooth endoplasmic reticulum (SER) and a varying number of mitochondria (many of them elongated) were common features of all hemocytes but were more evident in hyalinocytes because of their large cytoplasm and scarcity of granules (Figs 3 and 4). Hyalinocytes (Figs 3A and 4A–4C) also showed an eccentrically located nucleus and flattened and extended cisterns of the rough endoplasmic reticulum (RER), usually in the vicinity of the nucleus. Free ribosomes were frequently seen. Membrane-bound granules of moderate electron density (not recognized in HE stained preparations) were found in most hyalinocytes; they will be referred to as L granules, because of their similarity to lysosomes. The SER was formed by numerous round or oval small vesicles and sometimes by larger vacuoles. The Golgi apparatus was only infrequently found. Also, presumptive glycogen stores (not membrane-bound) were also occasionally seen (Fig 4B).


Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney.

Cueto JA, Rodriguez C, Vega IA, Castro-Vazquez A - PLoS ONE (2015)

Details of circulating hemocytes (TEM).(A) Cytoplasm of a hyalinocyte showing numerous mitochondria and some RER and SER profiles. (B) Detail of another hyalinocyte showing an extended RER cisterna, SER vesicles and a membrane-unbound zone with presumptive glycogen granules. (C) Cytoplasm of a hyalinocyte showing numerous SER vesicles, as well as a few L granules and mitochondria. (D) Cytoplasm of a granulocyte showing numerous R granules around a Golgi complex. Abbreviations: gly, presumptive glycogen granules; other abbreviations as in Fig 3. Scale bars represent 1 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4404100&req=5

pone.0123964.g004: Details of circulating hemocytes (TEM).(A) Cytoplasm of a hyalinocyte showing numerous mitochondria and some RER and SER profiles. (B) Detail of another hyalinocyte showing an extended RER cisterna, SER vesicles and a membrane-unbound zone with presumptive glycogen granules. (C) Cytoplasm of a hyalinocyte showing numerous SER vesicles, as well as a few L granules and mitochondria. (D) Cytoplasm of a granulocyte showing numerous R granules around a Golgi complex. Abbreviations: gly, presumptive glycogen granules; other abbreviations as in Fig 3. Scale bars represent 1 μm.
Mentions: A well developed smooth endoplasmic reticulum (SER) and a varying number of mitochondria (many of them elongated) were common features of all hemocytes but were more evident in hyalinocytes because of their large cytoplasm and scarcity of granules (Figs 3 and 4). Hyalinocytes (Figs 3A and 4A–4C) also showed an eccentrically located nucleus and flattened and extended cisterns of the rough endoplasmic reticulum (RER), usually in the vicinity of the nucleus. Free ribosomes were frequently seen. Membrane-bound granules of moderate electron density (not recognized in HE stained preparations) were found in most hyalinocytes; they will be referred to as L granules, because of their similarity to lysosomes. The SER was formed by numerous round or oval small vesicles and sometimes by larger vacuoles. The Golgi apparatus was only infrequently found. Also, presumptive glycogen stores (not membrane-bound) were also occasionally seen (Fig 4B).

Bottom Line: Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes.Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads.A role for the kidney as an immune barrier is proposed for this snail.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina; Instituto de Histología y Embriología "Dr. Mario H. Burgos", Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina.

ABSTRACT
Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail.

Show MeSH
Related in: MedlinePlus