Lipid melting and cuticular permeability: new insights into an old problem

2002 ◽  
Vol 48 (4) ◽  
pp. 391-400 ◽  
Author(s):  
Allen G. Gibbs
Keyword(s):  
Cuticular Permeability ◽  
Lipid Melting

Simultaneous Measurements of Spiracular and Cuticular Water Losses in Periplaneta Americana: Implications for Whole-Animal Mass Loss Studies

1991 ◽  
Vol 161 (1) ◽  
pp. 439-453 ◽  
Author(s):  
J. MACHIN ◽  
P. KESTLER ◽  
G. J. LAMPERT
Keyword(s):  
Water Loss ◽  
Periplaneta Americana ◽  
Water Losses ◽  
Initial Water ◽  
Variable Activity ◽  
Cuticular Permeability ◽  
Order Of Magnitude ◽  
Animal Mass ◽  
Principal Contributor ◽  
Water Contents

Spiracular and cutaneous water loss through the cuticle and spiracles of Periplaneta americana was measured in animals of differing initial water contents under controlled temperature, humidity and airflow conditions, by continuous weighing (resolution ±10μg). Stable water loss rates (2.09×10−8 to 3.47×10−8gh−1cm−2Pa−1) were as much as an order of magnitude less than those reported in earlier studies employing intermittent weighing techniques. We suggest that increased water loss caused by substantial increases in ventilatory water loss during the episodic disturbances required by intermittent weighing is the principal contributor to this discrepancy. Water losses, as well as the interval between spiracular ventilations, decreased with water content. However, greater variation was primarily due to interruptions of the regular cyclic pattern of ventilation by highly variable, activity-related bouts of increased ventilatory loss. Variations in water loss appear to be too large and too rapid to be convincingly explained in terms of cuticular conductance. Our results suggest that previous experiments using 5% CO2 anaesthesia, linking changes in total water loss to the conducting properties of the cuticle, were not valid. There seems to be no adaptive value for the proposed voluntary increases in cuticular permeability in an animal where ventilatory water losses can be so high.

scholarly journals DPPC Lipid Melting Transition in Concentrated Sucrose Solutions

2019 ◽  
Vol 116 (3) ◽  
pp. 79a
Author(s):  
Mattia I. Morandi ◽  
Fabrice J. Thalmann ◽  
Monika Kluzek ◽  
Andre P. Schroder ◽  
Carlos M. Marques
Keyword(s):  
Melting Transition ◽  
Sucrose Solutions ◽  
Lipid Melting

scholarly journals A modified method for enzymatic isolation of and subsequent wax extraction from Arabidopsis thaliana leaf cuticle

Plant Methods ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Martina Vráblová ◽  
Daniel Vrábl ◽  
Barbora Sokolová ◽  
Dominika Marková ◽  
Marie Hronková
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Genetic ◽  
Enzymatic Method ◽  
Wild Type ◽  
Genetic Studies ◽  
Modified Method ◽  
Enzymatic Isolation ◽  
Cuticular Permeability ◽  
Terrestrial Life ◽  
Intact Leaves

Abstract Background The plant cuticle represents one of the major adaptations of vascular plants to terrestrial life. Cuticular permeability and chemical composition differ among species. Arabidopsis thaliana is a widely used model for biochemical and molecular genetic studies in plants. However, attempts to isolate the intact cuticle from fresh leaves of Arabidopsis have failed so far. The goal of this study was to optimise an enzymatic method for cuticle isolation of species with a thin cuticle and to test it on several A. thaliana wild types and mutants. Results We developed a method for isolation of thin cuticles that allows reducing the isolation time, the separation of abaxial and adaxial cuticles, and avoids formation of wrinkles. Optical microscopy was used for studying cuticle intactness and scanning electron microscopy for visualisation of external and internal cuticle structures after isolation. Wax extracts were analysed by GC–MS. Isolation of intact cuticle was successful for all tested plants. The wax compositions (very-long-chained fatty acids, alcohols and alkanes) of intact leaves and isolated cuticles of wild type Col-0 were compared. Conclusions We conclude that the optimised enzymatic method is suitable for the isolation of A. thaliana adaxial and abaxial cuticles. The isolated cuticles are suitable for microscopic observation. Analysis of wax composition revealed some discrepancies between isolated cuticles and intact leaves with a higher yield of wax in isolated cuticles.

scholarly journals Comparative Cutaneous Water Loss and Desiccation Tolerance of Four Solenopsis spp. (Hymenoptera: Formicidae) in the Southeastern United States

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 418
Author(s):  
Olufemi S. Ajayi ◽  
Arthur G. Appel ◽  
Li Chen ◽  
Henry Y. Fadamiro
Keyword(s):  
Water Loss ◽  
Desiccation Tolerance ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Southeastern Usa ◽  
Cuticular Permeability ◽  
Lethal Time ◽  
Total Body ◽  
Terrestrial Insects

The high surface area to volume ratio of terrestrial insects makes them highly susceptible to desiccation mainly through the cuticle. Cuticular permeability (CP) is usually the most important factor limiting water loss in terrestrial insects. Water loss rate, percentage of total body water (%TBW) content, CP, and desiccation tolerance were investigated in workers of four Solenopsis species in the southeastern USA. We hypothesized that tropical/subtropical ants (S. invicta and S. geminata) will have lower CP values and tolerate higher levels of desiccation than temperate ants (S. richteri and S. invicta × S. richteri). The %TBW content was similar among species. Solenopsis invicta had a 1.3-fold and 1.1-fold lower CP value than S. invicta × S. richteri and S. richteri, respectively. Solenopsis geminata had a 1.3-fold lower CP value than S. invicta × S. richteri, and a 1.2-fold lower CP value than S. richteri. The LT50 values (lethal time to kill 50% of the population) ranged from 1.5 h (small S. geminata) to 8.5 h (large S. invicta). Desiccation tolerance ranged between 36 and 50 %TBW lost at death and was not related to a species’ location of origin. This study is the first report of water relations of S. invicta × S. richteri. It demonstrates that desiccation stress differentially can affect the survival of different Solenopsis species and implies that environmental stress can affect the distribution of these species in the southeastern USA.

Water Loss and Desiccation Tolerance of the Two Yearly Generations of Adult and Nymphal Kudzu Bugs, Megacopta cribraria (Hemiptera: Plataspidae)

2020 ◽  
Vol 49 (3) ◽  
pp. 651-659
Author(s):  
Gokhan Benk ◽  
Patrick J Thompson ◽  
Xing P Hu ◽  
Arthur G Appel
Keyword(s):  
Mass Loss ◽  
Water Loss ◽  
Desiccation Tolerance ◽  
First Generation ◽  
Second Generation ◽  
Generation Adult ◽  
Adult Females ◽  
Soybean Pest ◽  
Cuticular Permeability ◽  
Total Body

Abstract Water loss rate, percentage total body water content (%TBW), cuticular permeability (CP), and desiccation tolerance were investigated in adult and immature stages of the invasive kudzu bug, Megacopta cribraria (Fab.) (Hemiptera: Plataspidae), a serious soybean pest and an urban nuisance. Adults and all five nymphal instars were weighed prior to and 2, 4, 6, 8, 10, and 24 h after desiccated at 30 ± 1°C and 0–2% RH. Both % initial mass and %TBW loss increased linearly with time of desiccation. Rates of loss ranged from approximately 1–7%/h. Mortality occurred at 10 h after desiccation. Desiccation tolerance (%TBW lost at death) ranged between 25.6% for first-generation adult females and 75% for first-generation fifth-instar nymphs. First-generation first-instar nymphs had significantly greater %TBW (88.9%) than the other generations and instars, whereas second-generation fifth instars had the lowest %TBW (62.4%). The CP value of first-generation adult females (12.3 ± 1.6 µg cm−1 h−1 mmHg−1) was the greatest across generations. First-generation first instars had the greatest mass loss (111.11 mg/g) among all instars and generations, whereas overwintered second-generation adult females had the lowest mass loss (18.39) across generations. This study demonstrated that desiccation stress differentially affected the survival of adult and nymphal kudzu bugs and may imply that environmental stress can affect the relative abundance of this species in the fields and around homes.

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