Thoracic neurosecretory structures in brachyura III. Microanatomy of peripheral structures

The trunks of the brachyuran pericardial organs consist of an inner core of nerve fibers, connective tissue, and blood vessels and an outer cortex of secretory terminals. The terminals contain granules which can be visualized by darkfield, phase, or electron microscopy. A thin (less than 1 [mu]), amorphous, acellular epineurium separates the terminals from the surrounding hemolymph. Selective stains suggest that there may be three kinds of secretory terminal in the crab, Carcinus.The cortex ranges from about 20% of total pericardial organ volume in some specimens of Carcinus down to a negligible percentage in Libinia. Secretory granules form less than 10% of the volume of the terminals in the cortex.The electron dense secretory granules have an outer membrane. They range in diameter from about 0.05 to 0.5 [mu]. In Carcinus large (0.17 [mu]) and small (0.14 [mu]) granules occur in separate terminals. In Cancer only one population of granules has been found (0.15 [mu]). In Libinia terminals appear to contain either one (0.09 [mu]) or two populations (0.06 and 0.15 [mu]). In Carcinus and Cancer a third kind of terminal appears to contain vesicles about 0.03 to 0.05 [mu] in diameter.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32320/1/0000389.pd

Recordings from the stomatogastric nervous system in intact lobsters

1. 1. The neural output of the stomatogastric ganglion was recorded from intact lobsters with implanted electrodes.2. 2. The recorded discharge was rhythmic and patterned, and was similar to that recorded previously from isolated stomatogastric preparations.3. 3. Variations in the period and form of the output during quiescence and following feeding suggest that although rhythmic patterns probably originate in the stomatogastric ganglion, they are also under control of modulating interneurons from the central nervous system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32770/1/0000141.pd

Function of an eyestalk ganglion, the Medulla terminalis , in olfactory integration in the lobster, Panulirus argus

Ipsilateral antennular dysfunction resulting from total unilateral eyestalk ablation in spiny lobsters does not occur when visual input is restricted by an opaque cap over one eyestalk, or when optic ganglia alone (eg. lamina ganglionaris, medulla externa, medulla interna ) are removed. Antennular dysfunction appears only when connections between the most proximal of the four eyestalk ganglia, the medulla terminalis , and the remainder of the cerebral ganglia (brain) are interrupted. We conclude that neural processing of olfactory input from the antennule involves structures in the medulla terminalis .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47097/1/359_2004_Article_BF00340397.pd

Disturbance of feeding behavior in the spiny lobster, Panulirus argus , following bilateral ablation of the Medulla terminalis

1. Bilateral eyestalk ablation of spiny lobsters results in:Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47100/1/359_2004_Article_BF00297774.pd

The Development and Use of an Innovative Laboratory Method for Measuring Arsenic in Drinking Water from Western Bangladesh

All of Bangladesh’s approximately 10 million drinking-water tube wells must be periodically tested for arsenic. The magnitude of this task and the limited resources of Bangladesh have led to the use of low-cost, semiquantitative field kits that measure As to a relatively high 50 μg/L national drinking water standard. However, there is an urgent need to supplement and ultimately replace these field kits with an inexpensive laboratory method that can measure As to the more protective 10 μg/L World Health Organization (WHO) health-based drinking water guideline. Unfortunately, Bangladesh has limited access to atomic absorption spectrometers or other expensive instruments that can measure As to the WHO guideline of 10 μg/L. In response to this need, an inexpensive and highly sensitive laboratory method for measuring As has been developed. This new method is the only accurate, precise, and safe way to quantify As < 10 μg/L without expensive or highly specialized laboratory equipment. In this method, As is removed from the sample by reduction to arsine gas, collected in an absorber by oxidation to arsenic acid, colorized by a sequential reaction to arsenomolybdate, and quantified by spectrophotometry. We compared this method with the silver diethyldithiocarbamate [AgSCSN(CH(2)CH(3))(2)] and graphite furnace atomic absorption spectroscopy (GFAAS) methods for measuring As. Our method is more accurate, precise, and environmentally safe than the AgSCSN(CH(2)CH(3))(2) method, and it is more accurate and affordable than GFAAS. Finally, this study suggests that Bangladeshis will readily share drinking water with their neighbors to meet the more protective WHO guideline for As of 10 μg/L

An effect of eyestalk ablation on antennular function in the spiny lobster, Panulirus argus

1. Unilateral removal of the eyestalk (optic ganglia and medulla terminalis) in the Bermuda spiny lobster, Panulirus argus , disrupts normal initiation of feeding activity via chemo-tactile stimulation of the antennule on the side of the ablation. This deficit may be permanent for it has lasted without apparent remission for over five months and two molts. Unilateral eyestalk ablation also produces a temporary increase in antennular cleaning activity directed toward the antennule on the side of the ablation. This effect seems to last for less than 16 days. Unilateral eyestalk ablation does not appreciably disturb spontaneous antennular movements or responses to mechanical stimulation of the antennule on either side. Nor does it destroy the ability of the lobster to give differential responses to mechanical and chemo-tactile stimuli. Most lobsters recover normal sensory and motor functions in antennules that regenerate after amputation of the distal segment and sensory flagellae. In about 1/3 of the animals, however, some form of sensory or motor abnormality is evident in the regenerated antennule. These deficits are ascribed to occasional failure of regenerating neurons to reform appropriate central connections. They do not resemble the deficits following eyestalk ablation. The medulla terminalis is tentatively proposed as the portion of the nervous system critical for normal antennular function that is removed by eyestalk ablation. There seem to be similarities between the effects of eyestalk ablation in the Crustacea as described here and the effects following destruction of portions of the corpora pedunculata in insects. 1. Einseitige Entfernung des Augenstieles (optische Ganglien und Medulla terminalis) bei der Bermuda-Stachellanguste, Panulirus argus , unterbricht auf der operierten Seite den Beginn der normalen Freß-tätigkeit, die durch chemische und taktile Reizung der Antennula eingeleitet wird. Diese Störung kann irreversibel sein, denn sie überdauerte in über 5 Monaten zwei Häutungen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47096/1/359_2004_Article_BF00340474.pd

World Health Organization Discontinues Its Drinking-Water Guideline for Manganese

Background: The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because “this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value.

The evolution of language: a comparative review

For many years the evolution of language has been seen as a disreputable topic, mired in fanciful &quot;just so stories&quot; about language origins. However, in the last decade a new synthesis of modern linguistics, cognitive neuroscience and neo-Darwinian evolutionary theory has begun to make important contributions to our understanding of the biology and evolution of language. I review some of this recent progress, focusing on the value of the comparative method, which uses data from animal species to draw inferences about language evolution. Discussing speech first, I show how data concerning a wide variety of species, from monkeys to birds, can increase our understanding of the anatomical and neural mechanisms underlying human spoken language, and how bird and whale song provide insights into the ultimate evolutionary function of language. I discuss the ‘‘descended larynx’ ’ of humans, a peculiar adaptation for speech that has received much attention in the past, which despite earlier claims is not uniquely human. Then I will turn to the neural mechanisms underlying spoken language, pointing out the difficulties animals apparently experience in perceiving hierarchical structure in sounds, and stressing the importance of vocal imitation in the evolution of a spoken language. Turning to ultimate function, I suggest that communication among kin (especially between parents and offspring) played a crucial but neglected role in driving language evolution. Finally, I briefly discuss phylogeny, discussing hypotheses that offer plausible routes to human language from a non-linguistic chimp-like ancestor. I conclude that comparative data from living animals will be key to developing a richer, more interdisciplinary understanding of our most distinctively human trait: language