Intercellular Junctions in Insect Tissues

Lane, Nancy J.; Skaer, Helen

doi:10.1016/s0065-2806(08)60141-1

Cited by 171 publications

(61 citation statements)

References 442 publications

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“…This barrier consists of an outer acellular layer, which functions as a barrier to ions and osmolites in the hemolymph, and a second layer composed of perineural cells. The perineural cell layer is largely impermeable as a result of an abundance of tight and gap junctions (Lane and Skaer, 1980). The effects of CO 2 on spiracular function have been described (Hazelhoff, 1926;Wigglesworth, 1935;Hoyle, 1960), but the mechanism by which this signal is detected remains unknown.…”

Section: Analysis Of Temperature Effects On Gas Exchange Pattern Charmentioning

confidence: 99%

Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus

Heinrich

Bradley

2014

Journal of Experimental Biology

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Insects display an array of respiratory behaviors, including the use of discontinuous gas exchange. This pattern is characterized by periods of spiracular closure, micro-openings (flutter), and complete openings during which the majority of gas exchange takes place. A current model of insect spiracular control suggests that spiracles are controlled by two interacting feedback loops, which produce the discontinuous pattern. The flutter period is thought to be initiated by a critically low partial pressure of oxygen, while the open period is initiated by a critically high CO 2 threshold. The goal of our study was to test this control model under conditions of feeding-induced or temperature-induced changes in metabolic rate. We manipulated the metabolic rate of the insect Rhodnius prolixus using two discrete mechanisms: (1) feeding the insects a bloodmeal or (2) exposing them to a range of temperatures (18-38°C). Examining the variation in the gas exchange patterns produced by insects in each of these treatments allowed us to determine whether spiracular control is sensitive to metabolic rate and/or temperature. We found that increases in temperature caused significant decreases in open phase burst volumes and premature abandonment of discontinuous gas exchange cycles. These effects were not observed in fed individuals maintained at a single temperature despite their higher metabolic rates. Our results indicate that some part of the spiracular control mechanism is temperature sensitive, suggesting a possible role for pH in CO 2 sensing.

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Section: Analysis Of Temperature Effects On Gas Exchange Pattern Charmentioning

confidence: 99%

Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus

Heinrich

Bradley

2014

Journal of Experimental Biology

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“…These findings seem to suggest that alteration in external salt content did not trigger changes in the active transport machinery along the midgut epithelia of C. riparius, although this does not preclude changes in secondary ion transport processes or ultrastructural alterations of the epithelium, which may lead to alterations in ion transport function. For example, varying salinity may alter passive ion movement across the midgut because of the modulation of paracellular permeability, which is controlled by septate junctions (see Lane and Skaer, 1980). In this regard, the effects of environmental salinity on the permeability of intestinal epithelia in aquatic vertebrates such as fishes are well documented (see Marshall and Grosell, 2005).…”

Section: Differences In Nka and Va Activity In Different Rearing Envimentioning

confidence: 99%

Tissue specific ionomotive enzyme activity and K+ reabsorption reveal the rectum as an important ionoregulatory organ in larvalChironomous ripariusexposed to varying salinity

Jonusaite

Kelly

Donini

2013

Journal of Experimental Biology

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Summary A role for the rectum in the ionoregulatory homeostasis of larval Chironomus riparius was revealed by rearing animals in different saline environments and examining: (1) the spatial distribution and activity of keystone ionomotive enzymes Na+-K+-ATPase (NKA) and V-type H+-ATPase (VA) in the alimentary canal and (2) rectal K+ transport with scanning ion-selective electrode technique (SIET). NKA and VA activity were measured in four distinct regions of the alimentary canal as follows: the combined foregut and anterior midgut (FAMG), the posterior midgut (PMG), the Malpighian tubules (MT) and the hindgut (HG). Both enzymes exhibited 10 - 20 times greater activity in the HG relative to all other areas. When larvae were reared in either ion-poor water (IPW) or freshwater (FW), no significant difference in HG enzyme activity was observed. However, in brackish water (BW) reared animals, NKA and VA activity in the HG significantly decreased. Immunolocalization of NKA and VA in the HG revealed that the bulk of protein was located in the rectum. Therefore K+ transport across the rectum was examined using SIET. Measurement of K+ flux along the rectum revealed a net K+ reabsorption which was reduced four-fold in BW-reared larvae versus larvae reared in FW or IPW. Inhibition of NKA with ouabain, VA with bafilomycin and K+ channels with charybdotoxin, diminished rectal K+ reabsorption in FW- and IPW-reared larvae, but not BW-reared larvae. Data suggest that the rectum of C. riparius plays an important role in allowing these larvae to cope with dilute as well as salinated environmental conditions.

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“…They first appear midway through embryogenesis and are characterized by a ladder-like arrangement of septa crossing the intercellular cleft. SJs have been proposed to play a role in the formation of a trans-epithelial diffusion barrier, establishing and/or maintaining cell polarity, cell adhesion and cell-cell interactions (Tepass and Hartenstein, 1994;Tepass et al, 2001;Lane and Skaer, 1980;Noirot-Timothée and Noirot, 1980). Several proteins are known to associate with SJs, and many of these form supramolecular complexes (Knust and Bossinger, 2002;Tepass et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Lachesin is a component of a septate junction-based mechanism that controls tube size and epithelial integrity in theDrosophilatracheal system

et al. 2004

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Organ morphogenesis requires the coordinated activity of many mechanisms involved in cell rearrangements, size control, cell proliferation and organ integrity. Here we report that Lachesin (Lac), a cell surface protein, is required for the proper morphogenesis of the Drosophila tracheal system. Homozygous embryos for Lac mutations, which we find fail to complement the previous identified bulbous (

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Intercellular Junctions in Insect Tissues

Cited by 171 publications

References 442 publications

Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus

Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus

Tissue specific ionomotive enzyme activity and K+ reabsorption reveal the rectum as an important ionoregulatory organ in larvalChironomous ripariusexposed to varying salinity

Lachesin is a component of a septate junction-based mechanism that controls tube size and epithelial integrity in theDrosophilatracheal system

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