Cuticular Membranes Research Articles

The Micromorphology and Its Taxonomic Value of the Genus Sanicula L. in China (Apiaceae).

The genus Sanicula L. possesses many medically important plants, belonging to the family Apiaceae. It is one of the most taxonomically difficult taxa, largely due to the great variability in habit, foliage, flowers and fruits. Previous studies have mainly focused on the molecular studies of this genus, and the morphological research for this genus was limited, especially in the micromorphological research. In the current study, we newly obtained leaf materials from twenty-two Sanicula members, fruit and pollen materials from twenty Sanicula members and performed comprehensively micromorphological analyses for this complicated genus. The results of the leaf epidermis showed that the upper and lower epidermis were smooth and glabrous, and the cell shape was polygonal or irregular. The patterns of anticlinal wall were shallowly undulating, deeply undulating, subflat or flat. The cuticular membrane ornamentations were diverse, and some species had epidermal appendage. All Sanicula species observed the stomata in the lower epidermis, and only five species (S. rugulosa, S. elongata, S. hacquetioides, S. tienmuensis and S. elata) observed stomata in the upper epidermis, which can easily identify them from other Sanicula members. In addition, we found that the fruits scarcely compressed, and some fruits had their distinctive shape, such as the fruit shape of S. tienmuensis was subglobose, S. subgiraldii was broadly ovate and S. pengshuiensis was ellipsoid. All Sanicula taxa fruits surfaces were covered with prickles, bristles, protuberance, or tubercles, prickles were either long or short, uncinate or straight, rarely scale-like, ribs inconspicuous or slightly prominent, but the prickles/bristles/tubercles were different in shape, sparseness and arrangement. The vittae were distinct in S. rubriflora, S. chinensis, S. caerulescens, S. pengshuiensis, S. pauciflora, S. lamelligera, S. oviformis, S. flavovirens and S. elata, and the remaining taxa were obscure. These findings indicated that the fruits can clearly distinguish these Sanicula members. Furthermore, the micromorphological characteristics of pollen showed that the equatorial view included four shapes: ellipsoid, subrectangular, equatorially constricted and super-rectangular-equatorially constricted; and the polar view possessed four shapes: triangular, triangular-circular, suborbicular and trilobate circular. The germ furrow and the outer wall ornamentation of all Sanicula taxa were quite similar, indicating that the genus was a natural unit. In summary, our study promoted the improvement of a taxonomic system for the genus and also provided additional evidence for future taxonomic study of the genus Sanicula.

Ultrastructural diversity in the shell of Artemia resting eggs.

The shell of Artemia resting egg, which is a delicate multilayered envelope surrounding the inside diapause embryo, plays an important role in the survival strategy of Artemia. To date, the ultrastructure of resting eggshell has been studied for only handful populations, and knowledge about the diversity of shell structure is still limited. In this paper, resting eggs from 13 Artemia populations were studied by transmission electron microscopy. Results show that the basic configuration of resting eggshell is quite conservative, but variations are not uncommon in the fine ultrastructure of each main layer of the shell (e.g., the shape and distribution of the radially oriented pores in the cortical layer; the size, number and arrangement of chambers in the alveolar layer; and the development state of outer cuticular membrane [OCM]). The ultrastructural variation of eggshell seems not to be linked with species and reproductive mode of Artemia. Resting eggs from very high habitats (4300+ m above sea level [a.s.l.]) on Qinghai-Tibet Plateau and certain tropical salterns have a hypoplastic OCM, which may be related to the adaptation to habitat conditions such as low oxygen concentration. RESEARCH HIGHLIGHTS: Comparative study on resting eggs from 13 Artemia populations reveals high diversity in the fine structure of eggshell. Resting eggs from very high (4300+ m a.s.l.) habitats commonly have a hypoplastic OCM.

Butterfly wing color made of pigmented liquid

A previously undescribed mechanism underlying butterfly wing coloration patterns was discovered in two distantly related butterfly species, Siproeta stelenes and Philaethria diatonica. These butterflies have bright green wings, but the color pattern is not derived from solid pigments or nanostructures of the scales or from the color of the cuticular membrane but rather from a liquid retained in the wing membrane. Wing structure differs between the green and non-green areas. In the non-green region, the upper and lower cuticular membranes are attached to each other, whereas in the green region, we observed a space of 5-10μm where green liquid is held and living cells are present. A pigment analysis and tracer experiment revealed that the color of the liquid is derived from hemolymph components, bilin and carotenoid pigments. This discovery broadens our understanding of the diverse ways in which butterfly wings obtain their coloration and patterns.

Brassica juncea leaf cuticle contains xylose and mannose (xylomannan) which inhibit ice recrystallization on the leaf surface.

Conjugated sugars showed antifreeze activity in the cuticle by ice recrystallization inhibition rather than thermal hysteresis, enhancing freezing capacity at the surface of B. juncea leaves. Antifreeze biomolecules play a crucial role in mitigating the physical damage from frost by controlling extracellular ice crystal growth in plants. Antifreeze proteins (AFPs) are reported from the apoplast of different plants. Interestingly, there is no report about antifreeze properties of the cuticle. Here, we report the potential antifreeze activity in the Brassica juncea (BJ) leaf cuticle. Nano LC-MS/MS analysis of a cuticle protein enriched fraction (CPE) predicted over 30 putative AFPs using CryoProtect server and literature survey. Ice crystal morphology (ICM) and ice recrystallization inhibition (IRI) analysis of ABC supernatant showed heat and pronase-resistant, non-protein antifreeze activities as well as hexagonal ice crystals with TH of 0.17°C and IRI 46%. The ZipTip processed ABC supernatant (without peptides) had no effect on TH activity, confirming a non-protein antifreeze molecule contributing to activity. To understand the origin and to confirm the source of antifreeze activity, cuticular membranes were isolated by pectinase and cellulase hydrolysis. FTIR analysis of the intact cuticle showed xylose, mannose, cellulose, and glucose. Xylanase and cellulase treatments of the ZipTip processed ABC supernatant led to an increase in sugar content and 50% loss in antifreeze activity. UV spectroscopy and NMR analysis supported the finding of FTIR and enzyme hydrolysis suggesting the contribution of xylose and mannose to antifreeze activity. By TLC analysis, conjugated sugars were found in the cuticle. This work has opened up a new research area where the antifreeze capacity needs to be established with regard to complete characterization and mechanism of action of the antifreeze carbohydrates (conjugated sugars) on the leaf surface.

Progressive pericardial echinococcosis with intra- and extra-cardiac complications: a multidisciplinary approach

British Journal of Hospital MedicineEarly view Case ReportProgressive pericardial echinococcosis with intra- and extra-cardiac complications: a multidisciplinary approachJason L Walsh, Carine J Moezinia, Amit KJ Mandal, David Lawrence, Constantinos G MissourisJason L WalshCorrespondence to: Jason L Walsh; E-mail Address: [email protected]Department of Medicine, Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough, UKSearch for more papers by this author, Carine J MoeziniaDepartment of Medicine, University College Hospital London, London, UKSearch for more papers by this author, Amit KJ MandalDepartment of Medicine, Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough, UKSearch for more papers by this author, David LawrenceDepartment of Cardiothoracic Surgery, St Bartholomew's Hospital, London, UKSearch for more papers by this author, Constantinos G MissourisDepartment of Medicine, Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough, UKUniversity of Nicosia Medical School, CyprusSearch for more papers by this authorJason L Walsh; Carine J Moezinia; Amit KJ Mandal; David Lawrence; Constantinos G MissourisPublished Online:8 May 2023https://doi.org/10.12968/hmed.2022.0528AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail View article References European Centre for Disease Prevention and Control. Echinococcosis. Annual epidemiological report for 2020. 2022. https://www.ecdc.europa.eu/sites/default/files/documents/echinococcosis-annual-epidemiolpgical-report-2020.pdf (accessed 21 April 2023) Google ScholarUsluer O, Kaya SO, Samancilar O, Ceylan KC, Gursoy S. The effect of preoperative albendazole treatment on the cuticular membranes of pulmonary hydatid cysts: should it be administered preoperatively? Kardiochir Torakochirurgia Pol. 2014;1(1):26–29. https://doi.org/10.5114/kitp.2014.41926 Google Scholar FiguresReferencesRelatedDetails Ahead of PrintISSN (print): 1750-8460ISSN (online): 1759-7390 Metrics History Published online 8 May 2023 Information© MA Healthcare LimitedAcknowledgementsThe authors are indebted to Professor Peter Chiodini and Dr Clare Warrell at University College London Hospitals for parasitology and infectious diseases input.PDF download

Analysis of plant cuticles and their interactions with agrochemical surfactants using a 3D printed diffusion chamber

BackgroundDecades of research is available on their effects of single component surfactant on active ingredient diffusion across plant cuticular membranes, but ingredient diffusion is rarely analysed in the presence of commercial surfactants. Also, diffusion studies require expensive or specialized apparatus the fabrication of which often requires skilled labour and specialized facilities. In this research we have addressed both problems where the effects of four commercially available surfactants on a known tracer molecule were investigated using a 3D printed customized diffusion chamber.ResultsAs a proof-of-concept a customized 3D printed diffusion chamber was devised using two different thermoplastics and was successfully used in a range of diffusion tests . The effect of various solvents and surfactants on S. lycopersicum cuticular membrane indicated an increased rate of flux of tracer molecules across the membranes. This research has validated the application of 3D printing in diffusion sciences and demonstrated the flexibility and potential of this technique.ConclusionsUsing a 3D printed diffusion apparatus, the effect of commercial surfactants on molecular diffusion through isolated plant membranes was studied. Further, we have included here the steps involved in material selection, design, fabrication, and post processing procedures for successful recreation of the chamber. The customizability and rapid production process of the 3D printing demonstrates the power of additive manufacturing in the design and use of customizable labware.

Molecular mechanisms involved in fruit cracking: A review.

Several fleshy fruits are highly affected by cracking, a severe physiological disorder that compromises their quality and causes high economical losses to the producers. Cracking can occur due to physiological, genetic or environmental factors and may happen during fruit growth, development and ripening. Moreover, in fleshy fruits, exocarp plays an important role, acting as a mechanical protective barrier, defending against biotic or abiotic factors. Thus, when biochemical properties of the cuticle + epidermis + hypodermis are affected, cracks appear in the fruit skin. The identification of genes involved in development such as cell wall modifications, biosynthesis and transport of cuticular waxes, cuticular membrane deposition and associated transcription factors provides new insights to better understand how fruit cracking is affected by genetic factors. Amongst the major environmental stresses causing cracking are excessive water during fruit development, leading to imbalances in cations such as Ca. This review focus on expression of key genes in these pathways, in their influence in affected fruits and the potential for molecular breeding programs, aiming to develop cultivars more resistant to cracking under adverse environmental conditions.

Characterization of the early evolution of the amphibious Podostemaceae

Podostemaceae are torrenticolous lithophytes, which are submerged during the rainy season and flower after exposure in the dry season. The terrestrial ancestor likely colonized amphibious habitats with the submergence and exposure phases. To characterize the early evolution, we did a cladistic analysis of 60 characters for the three subfamilies, including the seed-to-ovule and capsule-to-ovary ratios measured here for 24 and 27 species representing the three subfamilies. The analysis found three major patterns of character evolution. The first pattern is shown by 23 one-state apomorphic characters, 17 of which are vegetative and six are reproductive. The former characters include thin cuticular membrane and epidermal cell wall, adhesive seed coat and hair/holdfast, and epilithic organs. The prominent flavonoids/anthocyanins likely protect the exposed plant body from intense UV radiation in the habitat. Each character is adapted to the torrenticolous, epilithic life in sunny rivers. The latter reproductive characteristics, e.g., single fertilization and reduced embryo, contribute to the short-term reproduction before plant death. Probably all apomorphies accomplished the successful invasion of the amphibious habitat in the early evolution. In the second pattern, the apomorphies of 30 apomorphic and plesiomorphic characters, e.g., apical-meristemless shoot, rootless plant and spathella, produced the remarkable within-family diversification. In the third pattern, the seven plesiomorphic characters apparently little contribute to the early submergent evolution. The climatic distribution of species-rich countries suggests that Podostemaceae unchangeably preferred a monsoon/savanna climate with many habitats.

Mechano‐Sensor for Proprioception Inspired by Ultrasensitive Slit‐Based Mechanosensilla

AbstractInternal mechanosensors, as the core component of a proprioceptive system, provide vital mechanical information from intelligent devices for adaptive motor control, mechanical fault diagnosis, and machining condition monitoring. However, developing a sophisticated mechanosensory structure that can be widely used is highly desirable to significantly improve the detection performance of internal mechanosensors. Coincidentally, in nature, optimized microscale slits of arachnids (e.g., scorpions and spiders) are ingeniously used as a mechanosensory structure for internal mechanosensilla to efficiently detect the inevitable internal mechanical feedbacks caused by self‐motion and external mechanical stimuli. Biological slit‐based mechano‐sensilla provide an attractive bio‐inspired strategy to use the controllable slit as the sensory structure to improve the perceptual performance of internal mechanosensors. In this study, the structure‐deformation‐performance coupling relationship of slit‐based mechano‐sensilla is explored through experiment and theoretical analysis. An artificial slit‐based mechanosensor is developed by mimicking the combined deformation properties of the slit and the ultrathin cuticular membrane covering the slit tail. This bio‐inspired mechanosensor shows excellent performance in terms of mechanical stability, response time, and sensitivity to mechanical signals. The research on a practical application highlights the importance of the unique basic “design” principles of the slit‐based mechano‐sensilla in improving the proprioceptive capability of smart engineering devices.

Bio-Inspired Mechano-Sensor Based on the Deformation of Slit Wake

Internal mechano-sensors, as an indispensable part of the proprioceptive system of intelligent equipment, have attracted enormous research interest because of their extremely crucial role in monitoring machining processes, real-time diagnosis of equipment faults, adaptive motor control and so on. The mechano-sensory structure with signal-transduction function is an important factor in determining the sensing performance of a mechano-sensor. However, contrary to the wide application of the cantilever beam as the sensory structure of external mechano-sensors in order to guarantee their exteroceptive ability, there is still a lack of an effective and widely used sensory structure to significantly improve the sensing performance of internal mechano-sensors. Here, inspired by the scorpion using the specialized slit as the sensory structure of internal mechano-sensilla, the slit is ingeniously used in the design of the engineered internal mechano-sensor. In order to improve the deformability of the slit wake, the hollowed-out design around the slit tail of biological mechano-sensilla is researched. Meanwhile, to mimic the easily deformed flexible cuticular membrane covering the slit, the ultrathin, flexible, crack-based strain sensor is used as the sensing element to cover the controllable slit wake. Based on the coupling deformation of the slit wake, as well as the flexible strain sensor, the slit-based mechano-sensor shows excellent sensing performance to various mechanical signals such as displacement and vibration signals.

High-humidity hot air impingement blanching (HHAIB): An emerging technology for tomato peeling

Peeling is an essential operation for tomato processing. A new peeling method, high-humidity hot air impingement blanching (HHAIB) heating technology, was developed as an alternative to the conventional lye and hot-water peeling to eliminate the use of chemicals and the discharge of wastewater. The current work explored the feasibility of HHAIB for tomato peeling. The effects of heating temperature (100–120 °C), relative humidity (20%–40%) and heating time (0–180 s) on the peeling performance were investigated. The optimum treatment was found to be 110 °C heating temperature in combination with 40% of relative humidity and 75 s treatment time, which resulted in lower peeling loss, firmness loss and color deterioration compared with other HHAIB conditions that achieved 100% peelability. The comparative study of optimized HHAIB peeling with conventional lye and hot-water peeling showed that HHAIB peeled tomato obtained lower peeling loss and firmness loss, and higher preservation of phytochemicals, antioxidant capacity and color. In addition, compared with fresh tomatoes, HHAIB processing increased the antioxidant activity, lycopene, and total phenolic content in peeled tomatoes by 16.01%, 10.46%, 12.80%, respectively. The laser scanning confocal microscopy image of fresh tomato skin surface and the scanning electron microscope images of peels and flesh showed that HHAIB caused cracking of the epidermis and melting of the cuticular membrane while reduced the serious damage of flesh. Industrial practicePeeling is a necessary step in tomato processing, which impacts subsequent processing efficiency and product quality. At present, the most common used peeling methods in the industry are hot water or/and alkali peeling, but it induces the loss of water-soluble nutrients, chemical residues and waste liquid treatment. Therefore, the industry urgently needs an alternative peeling technology. The current work shows that HHAIB is a very promising peeling technology as it not only has an excellent peeling performance, but also enhances the preservation of phytochemicals, antioxidant capacity and quality attributes compared to conventional lye and hot-water peeling.

An ARF1-binding factor triggering programmed cell death and periderm development in pear russet fruit skin.

Plants have a cuticular membrane (CM) and periderm membrane (PM), which act as barriers to terrestrial stresses. The CM covers primary organs with a continuous hydrophobic layer of waxes embedded in cutin, while the PM includes suberized cells stacked externally to the secondary tissues. The formation of native periderm is regulated by a postembryonic meristem phellogen that produces suberized phellem (cork) outwardly. However, the mechanism controlling phellogen differentiation to phellem remains to be clarified. Here, map-based cloning in a pear F1 population with segregation for periderm development in fruit skin facilitated the identification of an aspartic acid repeat deletion in Pyrus Periderm Programmed Cell Death 1.1 (PyPPCD1.1) that triggers phellogen activity for cork formation in russet fruit skin of pear. PyPPCD1.1 showed preferential expression in pear fruit skin, and the encoded protein shares a structural similarity to that of the viral capsid proteins. Aspartic acid deletion in PyPPCD1.1 weakened its nuclear localization but increased its accumulation in the chloroplast. The products of both PyPPCD1.1 and its recessive allele directly interact with ADP-ribosylation factor 1 (ARF1). PyPPCD1.1 triggered programmed cell death in an ARF1-dependent manner. Thus, this study identified the switch gene for programmed cell death and periderm development and provided a new molecular regulatory mechanism underlying the development of this trait.

Direct Evidence for a Radial Gradient in Age of the Apple Fruit Cuticle.

The pattern of cuticle deposition plays an important role in managing strain buildup in fruit cuticles. Cuticular strain is the primary trigger for numerous fruit-surface disorders in many fruit crop species. Recent evidence indicates a strain gradient may exist within the apple fruit cuticle. The outer layers of the cuticle are more strained and thus more susceptible to microcracking than the inner layers. A radial gradient in cuticle age is the most likely explanation. Our study aimed to establish whether (or not) deposition of new cutin in a developing apple fruit occurs on the inner surface of the cuticle, i.e., immediately abutting the outward-facing epidermal cell wall. Developing apples were fed with 13C oleic acid through the skin. Following a 14-d period for incorporation, the fruit was harvested and the cuticular membranes (CMs) isolated enzymatically. The CMs were then ablated to varying extents from the inner or the outer surfaces, using a cold atmospheric pressure plasma (CAPP). Afterwards, the ablated CMs were dewaxed and the 13C contents were determined by mass spectrometry. The incorporation of 13C in the cutin fraction was higher than in the wax fraction. The 13C content was highest in non-ablated, dewaxed CM (DCM) and decreased as ablation depth from the inner surface increased. There was no change in 13C content when ablation was carried out from the outer surface. As fruit development proceeded, more 13C label was found towards the middle of the DCM. These results offered direct evidence for deposition of cutin being on the inner surface of the cuticle, resulting in a radial gradient in cuticular age—the most recent deposition (youngest) being on the inner cuticle surface (abutting the epidermal cell wall) and the earliest deposition (oldest) being on the outer surface (abutting the atmosphere).

Low cuticle deposition rate in 'Apple' mango increases elastic strain, weakens the cuticle and increases russet.

Russeting compromises appearance and downgrades the market value of many fruitcrops, including of the mango cv. ‘Apple’. The objective was to identify the mechanistic basis of ‘Apple’ mango’s high susceptibility to russeting. We focused on fruit growth, cuticle deposition, stress/strain relaxation analysis and the mechanical properties of the cuticle. The non-susceptible mango cv. ‘Tommy Atkins’ served for comparison. Compared with ‘Tommy Atkins’, fruit of ‘Apple’ had a lower mass, a smaller surface area and a lower growth rate. There were little differences between the epidermal and hypodermal cells of ‘Apple’ and ‘Tommy Atkins’ including cell size, cell orientation and cell number. Lenticel density decreased during development, being lower in ‘Apple’ than in ‘Tommy Atkins’. The mean lenticel area increased during development but was consistently greater in ‘Apple’ than in ‘Tommy Atkins’. The deposition rate of the cuticular membrane was initially rapid but later slowed till it matched the area expansion rate, thereafter mass per unit area was effectively constant. The cuticle of ‘Apple’ is thinner than that of ‘Tommy Atkins’. Cumulative strain increased sigmoidally with fruit growth. Strains released stepwise on excision and isolation (εexc+iso), and on wax extraction (εextr) were higher in ‘Apple’ than in ‘Tommy Atkins’. Membrane stiffness increased during development being consistently lower in ‘Apple’ than in ‘Tommy Atkins’. Membrane fracture force (Fmax) was low and constant in developing ‘Apple’ but increased in ‘Tommy Atkin’. Membrane strain at fracture (εmax) decreased linearly during development but was lower in ‘Apple’ than in ‘Tommy Atkins’. Frequency of membrane failure associated with lenticels increased during development and was consistently higher in ‘Apple’ than in ‘Tommy Atkins’. The lower rate of cuticular deposition, the higher strain releases on excision, isolation and wax extraction and the weaker cuticle account for the high russet susceptibility of ‘Apple’ mango.

Water Sorption and Desorption of Isolated Cuticles From Three Woody Species With Focus on Ilex aquifolium.

The cuticle is a lipid-rich layer that protects aerial plant organs against multiple stress factors such as dehydration. In this study, cuticle composition and structure in relation to water loss are examined in a broad ecophysiological context, taking into consideration leaf age and side from Ilex aquifolium (holly) in comparison with Eucalyptus globulus (eucalypt) and Prunus laurocerasus (cherry laurel). Enzymatically isolated cuticular membranes from holly leaves were studied under three treatment conditions: natural (no chemical treatment), after dewaxing, and after methanolysis, and the rate of water loss was assessed. Structural and chemical changes were evaluated using different microscopy techniques and by Fourier transform infrared (FTIR) spectroscopy. The potential mechanisms of solute absorption by holly leaves were additionally evaluated, also testing if its prickly leaf margin may facilitate uptake. The results indicate that the treatment conditions led to structural changes, and that chemical composition was hardly affected because of the occurrence of cutan. Structural changes led to more hydrophilic adaxial surfaces, which retained more water and were more efficient than natural cuticles, while changes were not significant for abaxial surfaces. Across natural cuticles, age was a significant factor for eucalypt but not for holly. Young eucalypt cuticles were the group that absorbed more water and had the lowest water loss rate. When comparing older leaf cuticles of the three species, cherry laurel was found to absorb more water, which was, however, lost more slowly, compared with the other species. Evidence was gained that holly leaves can absorb foliar-applied solutes (traced after calcium chloride application) through the adaxial and abaxial surfaces, the adaxial mid veins, and to a lower extent, the spines. In conclusion, for the species examined, the results show variations in leaf cuticle composition and structure in relation to leaf ontogeny, and water sorption and desorption capacity.

Relationship of cuticle development with water loss and texture of pepper fruit

Postharvest water loss in pepper fruit (Capsicum annuum L.) reduces its shelf life. Fruit texture is one of the most important components of fruit quality for consumers. In this study, the anatomical traits of pepper fruit related to postharvest water loss and texture were assessed. There was a strong positive relationship between postharvest water loss and the thickness of the cuticular membrane, cuticular weight, total cutin weight, and polysaccharide-cutan weight. An amorphous fibrous structure that forms a path for diffusion and increases water loss was observed in the thick cuticle of the pericarp. In addition, positive correlations between the hardness of the exocarp and the weight of cuticular membrane, cutin content, and polysaccharide-cutan content were found. These results indicate that the thickness of the cuticular membrane wedged between subepidermal cells may influence water loss through the pericarp of pepper fruit and fruit with a high cutin and polysaccharide content have a hard tough texture.

The cephalothoracic sucker of sea lice (Crustacea: Copepoda: Caligidae): The functional importance of cuticular membrane ultrastructure

Sea lice adhere to the body surface of host fish with a cephalothoracic sucker. Caligus adheres to this substrate using legs 2 and 3, and the action of cephalothoracic muscles. Lunules, small, paired, anterior sucker-like structures, have a vital function in the initial step of adhering and contain a unique endocuticule containing elements that may behave like active matter and serve as the actuating mechanism. Cuticular membranes bordering the cephalothorax have a unique endocuticule with an undulating dorsal surface and a smooth ventral surface. A high-speed camera revealed that this undulation likely facilitates rapid automatic application of the sucker to the substrate. The cuticular membranes on the posterior margin of the first exopodal segment of leg 2 have a specialized endocuticle with tubules each surrounded by fine fibers. This reinforcement helps them to generate a posteriorly-directed jet of water. Opening-closing of these membranes is controlled by postero-anterior motion of the distal exopodal segments of leg 2. The outer cuticular membrane of leg 3 is simple, presumably effected by powerful extrinsic muscles. The consistency of sucker morphology within Caligus implies a highly stereotyped attachment behavior that is effective across a remarkable variety of fishes.

Influence of physio-chemical factors on high throughput plant regeneration and micro-morpho-anatomy of shoots of Ormocarpum sennoides (Willd.) DC

Ormocarpum sennoides (bone-knit) is a vulnerable medicinal plant species belongs to the family Leguminosae. The aim of the present study was to evaluate the influence of plant growth regulators (PGRs), additives (ascorbic acid, citric acid, adenine sulfate, and L-arginine), gelling agents (agar and phytagel™) and type of culture vessels on the quantitative and qualitative proliferation of shoots and the micro-morpho-anatomical state of the in vitro multiplied O. sennoides. The pre-treatment of single-node explants with antioxidants (citric acid and ascorbic acid) reduced phenolic exudates, and 93.8% bud breaking was observed on Murashige and Skoog’s (MS) medium with 1.5 mg L−1 6-benzylaminopurine (BAP). The highest rate of shoot enhancement (mean number of shoots) per explant (42.0 shoots with 6.3 cm length) was obtained on MS medium augmented with 0.5 mg L−1 each of BAP and indole-3 acetic acid (IAA) with additives. Defoliation was observed in agar-gelled medium whereas; thick and sturdy shoots with healthy leaves were detected on phytagelled MS medium. The liquid medium was found unsuitable for shoot proliferation as the shoots experienced defoliation and hyperhydricity in cultures. The micro-shoots were rooted on half strength MS medium supplemented with 2.0 mg L−1 indole-3 butyric acid (IBA) and hardened in a greenhouse. The leaves and shoots showed some characteristic anomalies in the cuticular membrane, epidermis, stomata, vein structures, chlorophyll development, hypertrophy in cortical cells, and lignifications in vascular elements when cultured in bottles capped with screw-caps. Such anomalies were absent with the shoots cultured in conical flasks capped with cotton plugs. The micro-morpho-anatomical evidences supported that MS medium gelled with phytagel™ containing additives with optimized PGRs in conical flasks could be the best physio-chemical parameters for qualitative and quantitative development of plantlets for the in vitro conservation of this vulnerable plant species.

Wax composition and concentration in jujube (Ziziphus jujuba Mill.) cultivars with differential resistance to fruit cracking

Fruit cracking is a key problem restricting the development of the jujube (Ziziphus jujuba) industry, and is closely related to the distribution of the wax layer on the surface of the fruit. Three jujube cultivars with different levels of cracking resistance, namely ‘Popozao’, ‘Banzao’, and ‘Hupingzao’, were selected for comparison. Cracks on the cuticular membrane (CM) of ‘Hupingzao’ widened and deepened during the coloring period. The wax level of highly cracking-resistant ‘Popozao’ was significantly higher than that of ‘Hupingzao’ during the fruit coloring period. The fruit wax composition of the three jujube cultivars were quite similar, consisting mainly of alkanes, triterpenoids, aldehydes, amines, phenols, esters, ketones, fatty acids, primary alcohols, and other, unclassified compounds. Fatty acids, primary alcohols, and alkanes were the predominant fruit wax compounds of the three cultivars. We further analyzed the carbon chain length of aliphatic compounds and found that the concentration of fatty acids in ‘Popozao’ was significantly lower than that in ‘Banzao’ and ‘Hupingzao’ during the coloring period. Moreover, C28–30 were the most abundant primary alcohols during fruit development.Highly cracking-resistant cultivar ‘Popozao’ contains more very-long-chain alkanes and aldehydes (carbon atom >20) than ‘Banzao’ and ‘Hupingzao’ during the coloring period. In addition, we assessed the expression levels of 11 genes involved in fatty acid biosynthesis, elongation, and degradation, and in wax biosynthesis. Gene expression analysis indicated that KCS1, CER1, CYP86B1, and CYP86A play crucial roles in wax formation on jujube fruit. In conclusion, fruit cracking was correlated with whether wax synthesis is coordinated with fruit enlargement and‘Popozao’ has a stronger ability to synthesize very-long-chain alkanes and aldehydes. Understanding the diff ;erences in the cuticular wax and the activities of the corresponding genes in jujube cultivars with different sensitivities to cracking will provide a specific way to prevent fruit cracking.

Shading affects fracture force and fracture strain of apple fruit skins

Simple observation shows that naturally shaded apple fruit are more prone to russeting than sun-exposed fruit. The formation of microcracks in the fruit skin is the first visible sign of russeting. Our objective was to establish the effects of different levels of shading on the mechanical properties of apple (Malus × domestica Borkh.) fruit skins.Exposure of developing ‘Idared’ apples to visible and UV light was varied by shade-bagging and by sampling fruit from naturally shaded and exposed positions in the canopy. Fruit exposure to UV light was also varied using UV-absorbing film. Epidermal skin segments were excised, the cuticular membranes were isolated enzymatically and both were subjected to uniaxial tensile testing.Partial shading or blocking of UV light decreased the frequency of fruit having a red surface and also reduced the intensity of the red coloration, as indexed by increases in hue angle. The stiffness of epidermal skin segments was not affected by partial shading but fracture force and fracture strain were decreased. Blockage of UV slightly increased stiffness and decreased fracture force and fracture strain. The stiffness, fracture force and fracture strain of isolated cuticle samples were all markedly less than of epidermal skin segments. This indicates that, regardless of light treatment (visible and/or UV), it is the cellular layers of the skin, not the cuticle, that represent the load-bearing structure.There were no effects of shading or of UV blockage on cell size, cell shape or cell aspect ratio of either epidermal or hypodermal cells, or on sizes of parenchyma cells.There were also no detectable effects of shading or of UV blockage on thickness or wax content of the cuticle.We conclude that the effect of shading (visible and UV light) on the mechanical properties of the apple fruit skin was small, but was nevertheless consistent with an increase in the russet susceptibility of shaded fruit.