Daniel J. Aneshansley

Three-Dimensional Root Phenotyping with a Novel Imaging and Software Platform

A novel imaging and software platform was developed for the high-throughput phenotyping of three-dimensional root traits during seedling development. To demonstrate the platform’s capacity, plants of two rice (Oryza sativa) genotypes, Azucena and IR64, were grown in a transparent gellan gum system and imaged daily for 10 d. Rotational image sequences consisting of 40 two-dimensional images were captured using an optically corrected digital imaging system. Three-dimensional root reconstructions were generated and analyzed using a custom-designed software, RootReader3D. Using the automated and interactive capabilities of RootReader3D, five rice root types were classified and 27 phenotypic root traits were measured to characterize these two genotypes. Where possible, measurements from the three-dimensional platform were validated and were highly correlated with conventional two-dimensional measurements. When comparing gellan gum-grown plants with those grown under hydroponic and sand culture, significant differences were detected in morphological root traits (P < 0.05). This highly flexible platform provides the capacity to measure root traits with a high degree of spatial and temporal resolution and will facilitate novel investigations into the development of entire root systems or selected components of root systems. In combination with the extensive genetic resources that are now available, this platform will be a powerful resource to further explore the molecular and genetic determinants of root system architecture.

Biochemistry at 100°C: Explosive Secretory Discharge of Bombardier Beetles (Brachinus)

The defensive chemical spray of bombardier beetles is ejected at 100�C, with a heat content of about 0.2 calorie per milligram.

Ultraviolet Video-Viewing: The Television Camera as an Insect Eve

A television camtiera, like the eyes of some insects, is sensitive to ultraviolet light. When equipped with an appropriate ultraviolet-transmitting lens, such a camera can be used for the direct examtiination of ultraviolet reflectiont patterns (for example, on flowers, butterflies) that are invisible to us, but visible to inisects.

Defensive behavior of a termite (Nasutitermes exitiosus)

Summary1.The defensive behavior of the termite Nasutitermes exitiosus (Termitidae, Nasutitermitinae) was studied in the field and laboratory. The termites were confronted with live arthropod enemies, mostly ants, and with animated mechanical dummies that served as surrogate enemies.2.Both soldier and worker termites take part in the defensive actions. The weapon of the soldier is the secretory spray from its frontal gland, ejected from the pointed nozzle, or rostrum, at the front of the head. The spray is a viscous entangling agent, capable of quickly hindering the mobility of ants. The secretion also acts as an irritant, inducing scratching and other preening reflexes that in turn cause the sticky contaminant to be further spread over the surface of the enemy. Bioassays with cockroaches and flies showed irritancy to be attributable to such monoterpenoid components of the secretion as α-pinene and β-pinene. Scanning electronmicrographs of sprayed ants revealed that the secretion can also cause such incidental topical effects as spiracular occlusion and blockage of sensilla. The worker termites have no special weapons, but they can effectively bite. Ants may be crushed by the bites, or they may be slowed down by workers clamped to them with their mandibles and thereby rendered more vulnerable to being sprayed by soldiers. None of the ants, spiders, and centipedes presented to our termites in laboratory tests survived the encounters.3.The soldiers secretion is an effective alarm pheromone. Once a target has been sprayed, other soldiers converge upon the site and deploy themselves around it. Attraction is effective up to a radius of 30 mm. Recruited soldiers add their own spray to target only if they are themselves assaulted upon arrival. Only direct contact stimulation causes soldiers to spray. The substance(s) in the secretion responsible for the alarm response remain(s) unknown. The workers are essentially unalarmed by fresh secretion.4.Recruited soldiers tend to remain longer beside a “lively” sprayed enemy than beside one that has already ceased moving. As was apparent from the tests with mechanical dummies, the soldiers seem to gauge liveliness directly by contact, and by monitoring the slight air motions engendered in the immediate vicinity of the enemy by its movements. Conventional sound and substrate vibration appear to be of minimal importance in the detection of liveliness.5.The attractiveness of discharged secretion to soldiers subsides with time, but more gradually than might be expected from an alarm pheromone. Even two days after discharge, secretion still elicits significant soldier approach rates. It is suggested that in nature, sprayed incapacitated enemies might be covered over by the workers with feces and soil, a behavior that could bring about a more timely blockage of the alarm signal.

Suspended solids characteristics from recirculating aquacultural systems and design implications

Abstract Fish culture water characterization provides basic information for treatment process design. Suspended solids from three recirculating aquacultural systems were investigated to determine specific gravity and particle size distribution. This research revealed that more than 95% of the suspended particles in these systems had a diameter less than 20 microns (μm). The specific gravity of the solid particles was determined as 1.19, resulting in a mean particle weight of 10.6×10 −7 mg. These small particles accounted for 40–70% of the total suspended solids by weight. The results suggest that methods toremove fine solids in recirculating system are necessary.

High‐throughput two‐dimensional root system phenotyping platform facilitates genetic analysis of root growth and development

High-throughput phenotyping of root systems requires a combination of specialized techniques and adaptable plant growth, root imaging and software tools. A custom phenotyping platform was designed to capture images of whole root systems, and novel software tools were developed to process and analyse these images. The platform and its components are adaptable to a wide range root phenotyping studies using diverse growth systems (hydroponics, paper pouches, gel and soil) involving several plant species, including, but not limited to, rice, maize, sorghum, tomato and Arabidopsis. The RootReader2D software tool is free and publicly available and was designed with both user-guided and automated features that increase flexibility and enhance efficiency when measuring root growth traits from specific roots or entire root systems during large-scale phenotyping studies. To demonstrate the unique capabilities and high-throughput capacity of this phenotyping platform for studying root systems, genome-wide association studies on rice (Oryza sativa) and maize (Zea mays) root growth were performed and root traits related to aluminium (Al) tolerance were analysed on the parents of the maize nested association mapping (NAM) population.

Chemistry of defensive secretions of bombardier beetles (Brachinini, Metriini, Ozaenini, Paussini)☆

Abstract Data are given on the chemical composition of the defensive secretions of species of carabids of the genera Brachinus, Stenaptinus, Metrius, Goniotropis, Pachyteles, Ozaena, and Homopterus. All produce quinonoid secretions, containing from one to three of four different benzoquinones (1,4-benzoquinone; 2-methyl-1,4-benzoquinone; 2,3-dimethyl-1,4-benzoquinone; 2-methyl-3-methoxy-1,4-benzoquinone). In most species the secretions also contain n-alkanes (tridecane, tetradecane, pentadecane).

Plant Taxonomy: Ultraviolet Patterns of Flowers Visible as Fluorescent Patterns in Pressed Herbarium Specimens

Pressed flowers, in herbarium specimens, show visible fluorescent patterns matching the invisible ultraviolet patterns that the flowers show in life. The technique is taxonomically applicable since it makes an important but usually neglected floral character readily demonstrable.

Gap junctions in Malpighian tubules of Aedes aegypti

SUMMARY We present electrical, physiological and molecular evidence for substantial electrical coupling of epithelial cells in Malpighian tubules via gap junctions. Current was injected into one principal cell of the isolated Malpighian tubule and membrane voltage deflections were measured in that cell and in two neighboring principal cells. By short-circuiting the transepithelial voltage with the diuretic peptide leucokinin-VIII we largely eliminated electrical coupling of principal cells through the tubule lumen, thereby allowing coupling through gap junctions to be analyzed. The analysis of an equivalent electrical circuit of the tubule yielded an average gap-junction resistance (Rgj) of 431 kΩ between two cells. This resistance would stem from 6190 open gap-junctional channels, assuming the high single gap-junction conductance of 375 pS found in vertebrate tissues. The addition of the calcium ionophore A23187 (2 μmol l–1) to the peritubular Ringer bath containing 1.7 mmol l–1 Ca2+ did not affect the gap-junction resistance, but metabolic inhibition of the tubule with dinitrophenol (0.5 mmol l–1) increased the gap-junction resistance 66-fold, suggesting the regulation of gap junctions by ATP. Lucifer Yellow injected into a principal cell did not appear in neighboring principal cells. Thus, gap junctions allow the passage of current but not Lucifer Yellow. Using RT-PCR we found evidence for the expression of innexins 1, 2, 3 and 7 (named after their homologues in Drosophila) in Malpighian tubules. The physiological demonstration of gap junctions and the molecular evidence for innexin in Malpighian tubules of Aedes aegypti call for the double cable model of the tubule, which will improve the measurement and the interpretation of electrophysiological data collected from Malpighian tubules.

Detecting internal breakdown in apples using interactance measurements

Abstract A technique using body transmittance in the 450- to 1050-nm region was evaluated as a non-destructive technique for identifying apples with internal breakdown. Apples with internal breakdown absorbed shorter wavelengths of light ( 750 nm) was absorbed more by good apples than detective ones. A classifier based on the ratio between the light intensity at 720 and 810 nm was used to segregate apples with internal breakdown from good apples. Only 6.3% of the good apples were incorrectly classified; however. bruises on the apples contributed to the incorrect classification of good apples. None of the apples with severe internal breakdown were incorrectly classified. Apples with very slight internal breakdown contributed to most of the 12.0% error of misclassifying defective fruit as good. The number of misclassified apples was reduced by adjusting the cut-off; however, the number of good fruit that would be discarded increased.