Biochemical examination of fetal skin biopsy specimens obtained by fetoscopy: Use of the method for analysis of keratins and filaggrin

This paper describes a method for biochemical analysis of proteins from fetal skin biopsy samples. The method has wide potential application for diagnosis of disorders with a known protein abnormality detectable by protein staining or a specific antibody. Analysis requires a single 1 mm biopsy, is rapid (2 days) and extremely sensitive. In the present study, fetal skin biopsies from normal fetuses and a fetus at risk for lamellar ichthyosis were obtained. The epidermis or hairs with attached follicular cells were dissected from the remaining skin. Proteins were extracted and separated by SDS-polyacrylamide gel electrophoresis. Proteins from duplicate gels were transferred to nitrocellulose and immunostained for the acidic and basic keratins and for the keratin filament associated protein, filaggrin, using monoclonal antibodies. All samples contained keratins typical of fetal epidermis at 20 weeks gestation. Presence of filaggrin is variable at this age and depends on the presence of keratinized cells of hair canals. No keratin abnormalities in the fetus at risk for lamellar ichthyosis were detected, however, in one presumably normal biopsy, an abnormally low proportion of the 67 kd keratin and the presence of follicular keratins were evident. These results demonstrate that biochemical analysis of fetal biopsies is possible, thus increasing the diagnostic potential of the fetal biopsy procedure for disorders in which a known protein or antigen is altered in utero.     

Prenatal diagnosis of thrombocytopenia absent radius syndrome using ultrasound and fetoscopy

The prenatal diagnosis of thrombocytopenia absent radius syndrome in both dizygotic twins utilizing ultrasound, radiography and fetoscopy is described.     

Effects of colony size and stage of development on defense response by the swarm-founding wasp<Emphasis Type="Italic"> Polybia occidentalis</Emphasis>

In social insects the level of defensive effort generally increases with colony size, but the effects of the size of the defending adult population and the size of the brood population being defended have not been separated. We used pre-emergence-stage colonies of the swarm-founding wasp, Polybia occidentalis, to distinguish the effects of these two parameters on the intensity of colony defense. We elicited defensive behavior by using both mechanical (taps) and chemical (alarm-pheromone-containing venom) stimuli, and scored the responses as the number of attacks on a standard target. The intensity of defense increased linearly throughout the colony's first 25 days of development, despite the decrease in absolute numbers of adults during the same period. That is, the per capita attack rate increased strongly during this period, leading us to conclude that the intensity of defense is a function of the colony's investment in brood and not of the number of defending adults. We provide evidence that the increase is attributable neither to sensitization due to frequent disturbance, nor to the aging of the adult wasps. We further show that defensive effort on a per capita basis decreased with increasing size across colonies, whether colony size was measured as number of adults or as investment in brood. This pattern suggests that the cost-benefit relationship of defending the colony changes with colony size.Communicated by R.F.A. Moritz     

Simulated green turtle grazing affects nutrient composition of the seagrass <Emphasis Type="Italic">Thalassia testudinum</Emphasis>

Before populations of green turtles (Chelonia mydas) were severely reduced by human overexploitation, the seagrass Thalassia testudinum was intensively grazed by green turtles in the Caribbean. To explore how nutrient composition of T. testudinum pastures responds to intense grazing pressure, we simulated green turtle grazing in 15 plots (each 3 m × 3 m) for 16 months in the central Bahamas. Comparisons of clipped plots with 15 adjacent control (unclipped) plots revealed that simulated grazing resulted in significantly higher energy, nitrogen, phosphorus, lignin, cutin, and condensed tannin content in blades in clipped plots, but sediment organic content was not affected. By continually re-cropping blades in grazing plots, turtles ingest young, actively growing blade tissue with higher energy, nitrogen, and phosphorus concentrations. Our 16-month clipping trial did not generate the expected decline in nutrient content in T. testudinum blades under intensive grazing. However, significant decreases in nitrogen and organic matter reserves in rhizomes, with declines apparent after 16 and 11 months, respectively, indicate that nutrient content of blades and/or blade productivity may decline under continued clipping.     

Habitat influences on reproductive allocation and growth of the mummichog (<Emphasis Type="Italic">Fundulus heteroclitus</Emphasis>) in a coastal salt marsh

To determine whether life history differences can occur in salt marsh fishes that occupy different habitats within the same marsh, we compared reproductive allocation in female mummichog (Fundulus heteroclitus) inhabiting creeks and ponds of a coastal salt marsh in southern New Jersey, USA during the spring and summer of 2001 and 2002. Females were collected in phase with the lunar spawning cycle from four sites of each habitat type, and assessed for gonad-to-body-mass ratio and growth increment. Annual reproductive allocation, expressed as a percent of somatic mass, was estimated for each site and year from the gonadosomatic indices of individuals collected during each spawning period. Mummichogs from creeks showed little change in annual reproductive allocation from 2001 to 2002, whereas those inhabiting ponds showed a significant increase between these years. Seasonal reproductive patterns indicated that pond females cease spawning at least one lunar cycle earlier than creek fish. While ponds experienced considerably higher maximum summer temperatures than creeks as well as near-anoxic pre-dawn conditions, neither of these variables explained a significant amount of variation in annual reproductive allocation. In contrast, annual reproductive allocation of mummichogs in a pond correlated with its flood frequency in both years of study. Our results suggest that while the length of the spawning season differs in mummichogs inhabiting marsh creeks and ponds, annual reproductive allocation depends more upon the hydrodynamic conditions of the particular waterbody than its habitat type per se.     

Parasite faunas,testosterone and secondary sexual traits in male red-winged blackbirds

Summary We examined associations among parasite infections, secondary sexual traits and testosterone in male red-winged blackbirds sampled at the start of the breeding season. Parasites quantified included ectoparasitic lice and mites and endoparasitic blood protozoans, nematodes, trematodes and cestodes. Secondary sexual traits that we quantified included body size, epaulet size and color, song repertoire size and song switching rate, and behavioral responses to male and female models. Overall we found few significant associations between parasites and secondary sexual traits, between secondary sexual traits and testosterone, or between parasites and testosterone. In addition, most parasite taxa appeared to infect birds independently, although the low prevalence (<50%) of many of the parasites meant that our sample sizes were too small to detect weak associations. Our most promising results were obtained for ectoparasitic mites, which tended to occur on birds uninfected with other parasites, on birds with longer epaulets, and on birds with higher levels of testosterone. Epaulet length and testosterone are both probable correlates of dominance in this species. Further research will be required to determine whether there is a causal link between the immunosuppressive effects of testosterone and the mite infections, and between testosterone, epaulet length and male mating success. Correspondence to: P. Weatherhead     

Source of lead in humans from Broken Hill mining community

This paper documents the first precise lead isotope measurements for men, women and children from the same family in an attempt to determine the source of lead in their blood. The subjects reside in one of the world's largest lead mining cities, Broken Hill, NSW, Australia. Biological and environmental samples have been compared using isotopic compositions and lead contents. Adult males have isotopic profiles (or compositions) which appear to be related to their occupations. Adult females have low blood leads (<10 g dL^–1) and their main source of lead is not from the mine dumps around which the city is built but probably from a mixture of petrol, food and perhaps water. The blood lead contents in children from 1 to 14 years old vary and are partly dependent on age. There is a moderate correlation of blood lead and isotopic compositions (r = 0.73) indicating that a significant component of blood lead derives from the mine dumps in children with elevated blood leads. Some children with blood leads <20 g dL^–1, however, also have a dominant component of mine lead in their blood     

Genetic Analyses to Establish Captive Breeding Priorities for Endangered Snake River Sockeye Salmon

The plight of the Snake River sockeye salmon presents a challenging genetic puzzle for conservation biologists. Although the Snake River sockeye has been declared endangered, assessment of captive breeding strategies are complicated because a healthy non-migratory strain of O. nerka (kokanee) resides in Redfish Lake, Idaho—the same lake the anadromous fish return to for spawning. The migration of 1-year-old fish (outmigrants) from the lake each year and the observation of non-migratory fish spawning in areas previously used by the sockeye further complicate the issue. We estimated the relatedness of these strains by direct examination of their genetic similarity. Mixed DNA fingerprint analyses suggested that the outmigrants were more closely related to the anadromous sockeye than to the kokanee. Closer analysis using a probe, One-HO.8, to examine allele frequencies at a single locus revealed polymorphism in a number of O. nerka populations. Within the Redfish Lake populations this probe detected an allele present at 0.21 frequency in the kokanee (n = 43), 0.01 (n = 324) in the outmigrants, and absent among 13 anadromous fish. These results support a close genetic relationship of the outmigrants to the anadromous sockeye and the probable utility of the outmigrants in a captive breeding program to restore the anadromous strain.     

Color bands function as secondary sexual traits in male red-winged blackbirds

Summary We present the first experiment to assess band color effects in a natural bird population. 38 territorial male red-winged blackbirds (Agelaius phoeniceus) were randomly assigned to 1 of 2 banding treatments. They received either all red bands (to match their epaulets) or all black bands (controls). Over half the red-banded males lost their territories while all black-banded males retained their territories. Red and black-banded males did not differ morphologically. However, among red-banded males, those that lost their territories had larger epaulets and were in poorer condition than those retaining their territories. Red-banded males suffered much higher intrusion rates, particularly by neighbors, than black-banded males. We propose that red color bands exaggerated the males' natural aggressive signal beyond the point where the signal was reliable. Our results suggest that signal reliability is maintained by regular testing, particularly of those males most likely to be signalling dishonestly. Offprint requests to: K.J. Metz     

Incidental detection of premature centromere separation in amniocytes associated with a mild form of Roberts syndrome

Premature centromere separation (PCS) was detected in amniocytes after an amniocentesis was done because of markedly elevated maternal serum alpha-fetoprotein values in a healthy primiparous young woman. PCS has been associated with the Roberts-SC phocomelia syndrome (RS). By 23 weeks' gestation, ultrasonic evaluations did not reveal abnormal fetal development. The pregnancy continued and a male infant was born with mild manifestations of RS. PCS was confirmed in cord blood lymphocytes. This case illustrates that PCS, when detected in amniotic fluid cell cultures, requires a thorough evaluation.