William G. Hagar

Nonlethal Sampling of Sunfish and Slimy Sculpin for Stable Isotope Analysis: How Scale and Fin Tissue Compare with Muscle Tissue

Abstract We found that the sampling of tissues that do not result in the death of the fish, such as scale and fin tissue, may be substituted for muscle tissue in stable isotope analysis (SIA) of fishes. Comparisons were made between the values of δ13C and δ15N found in muscle tissue with the corresponding scale tissue of three sunfish species (bluegill Lepomis macrochirus, pumpkinseed L. gibbosus, and redbreast sunfish L. auritus) and with caudal fin tissue of slimy sculpin Cottus cognatus. The fish showed strong linear correlation in δ13C values between their nonlethally sampled scale or fin tissue and their muscle tissue (combined sunfish: r = 0.97; slimy sculpin: r = 0.84). Sunfish δ13C values were higher in scale tissue than in muscle tissue and required a correction factor for converting the scale values to the muscle values (regression equation: y = 1.1673x + 1.0531). Slimy sculpin δ13C fin and muscle values were similar and did not require a correction factor. The correlation of δ15N values between...

Comparing and assessing acid rain-sensitive ponds

Changes in pH and temperature were monitored in two freshwater ponds in Southeastern Massachusetts from 1990 to 1993 using a remote-sensing system that collected data on a continuous basis. The sensing system included a combination electrode, pH meter and portable computer powered by a marine battery. Temperature and pH information from the pH meter were acquired every 10 min and stored in the computer. The two ponds, located within 2 km of one another, have a different average pH and sensitivity to acid precipitation. Maquan Pond has an average pH of 6.0 and an alkalinity of 7.4 mg/l, while Furnace Pond has an average pH of 6.9 and alkalinity of 14.9 mg/l. The pH of both ponds varied seasonally and showed diel changes due to the photosynthetic and respiratory activity of aquatic organisms. Precipitation events did not change the pH of Furnace Pond. Maquan Pond on the other hand, did exhibit changes in surface water pH due to specific acidic precipitation events. During certain rainstorms, the pH of Maquan surface waters dropped to values as low as pH 4. In addition to the transient changes in pH, the acid-sensitive pond also exhibited differences in planktonic distribution patterns.

A tribute to Thomas Roosevelt Punnett, Jr. (1926–2008)

We honor here Thomas (Tom) Roosevelt Punnett, Jr. (May 25, 1926–July 4, 2008), who was a pioneer of Biology, particularly of biochemistry of plants and algae, having specialized in photosynthesis under Robert Emerson of the University of Illinois at Urbana-Champaign. He did exciting work on regulation and control of various metabolic reactions. He was an innovator and raconteur par excellence, and he prized critical thinking. His enthusiasm for basic science questions was matched by his grasp of their “real-world” implications. His last project was a patent for anaerobic sewage treatment that he hoped would lead to solution of waste disposal and energy creation world wide, including the clean-up of Lake Erie, where he had sailed as a boy. On the personal side, he had a strong sense of morality and a great wit and humor.

Observation of a triplet state in chlorophyll protein 668 via optically detected magnetic resonance

We have investigated the photo-excited triplet state properties of a species contained in the watersoluble chlorophyll protein (Cp 668) extracted from the stems of young plants of Atriplex hortensis using optically detected magnetic resonance (ODMR). The main absorption band of the material occurs at 668 nm with additional regions of absorption to the blue. Upon illumination in the presence of an electron acceptor such as oxygen, a new absorption band appears at 743 nm, while the AM8 peak decreases in intensity [l-3]. The fully converted state, Cp 743, is never observed in intact plants, or in plant extracts, so its photoconversion does not seem to be the primary function of this unique water-soluble chlorophyll protein [2-51. In an effort to understand the photoreactive state of Cp 668 and the involvement of triplet states in chlorophyll proteins the following study was undertaken from which we present the first ODMR results. Some preliminary triplet state data for Cp 668 have been presented [6]. Investigation into the triplet state sublevel characteristics of non-bacterial photosynthetic systems has been limited to chloroplast preparations [7], and various algae [8,9]. In reduced chloroplasts, and in algae, monomeric chlorophyll II type transitions were found [7-91. We shall discuss our findings with reference to the results for non-bacterial systems.

Interactive water monitoring system accessible by cordless telephone

A battery‐operated, microcomputer‐controlled monitoring device linked with a cordless telephone has been developed for remote measurements. This environmental sensor is self‐contained and collects and processes data according to the information sent to its on‐board computer system. An RCA model 1805 microprocessor forms the basic controller with a program encoded in memory for data acquisition and analysis. Signals from analog sensing devices used to monitor the environment are converted into digital signals and stored in random access memory of the microcomputer. This remote sensing system is linked to the laboratory by means of a cordless telephone whose base unit is connected to regular telephone lines. This offshore sensing system is simply accessed by a phone call originating from a computer terminal in the laboratory. Data acquisition is initiated upon request: Information continues to be processed and stored until the computer is reprogrammed by another phone call request. Information obtained may ...

Alterations in Photosynthetic Pigment Synthesis in Tissue Cultured Tobacco Callus

Tobacco stem pith in tissue culture forms green callus, followed by shoot regeneration. Inclusion of excess manganese (10 mM) in the medium leads to inhibition of growth and of photosynthetic pigment biosynthesis. Growth is inhibited about 40% throughout the 7 week period of study. Pigment synthesis is initially delayed in manganese treated cultures, then the extent of inhibition decreases. The amounts of lutein and β-carotene relative to chlorophyll a. are reduced during the first few weeks of manganese treatment7 while the relative amount of chlorophyll b remains the same. During later stages of manganese treatment, both lutein and chlorophyll b increase relative to chlorophyll a.