Parthenogenesis in a whitetip reef shark Triaenodon obesus involves a reduction in ploidy.

Genetic analysis of a female whitetip reef shark Triaenodon obesus and her stillborn pup, assumed to be of parthenogenetic origin, revealed that the pup was homozygous at all 24 nuclear-encoded microsatellites assayed, consistent with the idea that diploidy in the pup had been restored via terminal fusion. Flow cytometric analysis, however, indicated that the genome size of the pup was no more than half that of the mother, and microscopy revealed that nuclear volume was c. 1.73 times larger in the mother than in the pup. Together these data suggest that the pup was genetically haploid, developing directly from an unfertilized egg; as far as is known, this is the first observation of a spontaneously produced haploid vertebrate.

Genome size and ploidy of Thysanoptera.

Flow cytometry was used to study the genome sizes and ploidy levels for four thrips species: Franklinothrips orizabensis Johansen (Thysanoptera: Aeolothripidae), Frankliniella occidentalis Pergande, Frankliniella fusca Hinds, and Thrips tabaci Lindeman (Thysanoptera: Thripidae). F. orizabensis males and females had 1C genome sizes of 426 Mb and 422 Mb, respectively. Male and female F. fusca had 1C genome sizes of 392 Mb and 409 Mb, whereas F. occidentalis males and females had smaller 1C genomes that were 345 Mb and 337 Mb, respectively. Male F. orizabensis, F. occidentalis and F. fusca were haploid and females diploid. Five isofemale lines of T. tabaci, initiated from parthenogenetic, thelytokous females and collected from different locations in North Carolina, were included in this study; no males were available. One isofemale line was diploid with a genome size of 1C = 310 Mb, and the other four had a mean genome size of 1C = 482 Mb, which is consistent with evidence from microsatellite data of diploidy and polyploidy, respectively, in these same five thelytokous lines. This is the first study to produce genome size estimates for thysanopteran species, and report polyploidy in T. tabaci populations.

Genome sizes of forensically relevant Diptera.

Genome size estimates for both sexes of forensically relevant Diptera from 17 species (four families) are reported herein. Average genome sizes ranged from 425.8 Mb for female Chrysomya rufifacies to 1,197.4 Mb for male Haematobia irritans. These estimates are useful not only for molecular studies, but also for determination of the species and sex of immatures. Species in three of the sampled families had sexually dimorphic genome sizes, presenting a new tool useful for the determination of sex in these species, especially in the immature stages where sexes are morphologically difficult or impossible to identify. In addition, closely related species had significantly different genome sizes, suggesting the use of flow cytometry as a new tool for species identification of some species of forensically relevant larvae.

Evidence for DNA loss as a determinant of genome size.

Eukaryotic genome sizes range over five orders of magnitude. This variation cannot be explained by differences in organismic complexity (the C value paradox). To test the hypothesis that some variation in genome size can be attributed to differences in the patterns of insertion and deletion (indel) mutations among organisms, this study examines the indel spectrum in Laupala crickets, which have a genome size 11 times larger than that of Drosophila. Consistent with the hypothesis, DNA loss is more than 40 times slower in Laupala than in Drosophila.

Genome size diversity in the family Drosophilidae.

Flies in the genus Drosophila have been the dominant model organisms in genetics for over a century and, with a dozen complete sequences now available, continue as such in modern comparative genomics. Surprisingly, estimates of genome size for this genus have been relatively sparse, covering less than 2% of species. Here, best practice flow cytometric genome size estimates are reported for both male and female flies from 67 species from six genera in the family Drosophilidae, including 55 species from the genus Drosophila. Direct and phylogenetically corrected correlation analyses indicate that genome size is positively correlated with temperature-controlled duration of development in Drosophila, and there is indication that genome size may be positively related to body size and sperm length in this genus. These findings may provide some explanation for the streamlined genomes found in these insects, and complement recent work demonstrating possible selective constraints on further deletion of noncoding DNA.

Sequencing of a new target genome: the Pediculus humanus humanus (Phthiraptera: Pediculidae) genome project.

The human body louse, Pediculus humanus humanus (L.), and the human head louse, Pediculus humanus capitis, belong to the hemimetabolous order Phthiraptera. The body louse is the primary vector that transmits the bacterial agents of louse-borne relapsing fever, trench fever, and epidemic typhus. The genomes of the bacterial causative agents of several of these aforementioned diseases have been sequenced. Thus, determining the body louse genome will enhance studies of host-vector-pathogen interactions. Although not important as a major disease vector, head lice are of major social concern. Resistance to traditional pesticides used to control head and body lice have developed. It is imperative that new molecular targets be discovered for the development of novel compounds to control these insects. No complete genome sequence exists for a hemimetabolous insect species primarily because hemimetabolous insects often have large (2000 Mb) to very large (up to 16,300 Mb) genomes. Fortuitously, we determined that the human body louse has one of the smallest genome sizes known in insects, suggesting it may be a suitable choice as a minimal hemimetabolous genome in which many genes have been eliminated during its adaptation to human parasitism. Because many louse species infest birds and mammals, the body louse genome-sequencing project will facilitate studies of their comparative genomics. A 6-8X coverage of the body louse genome, plus sequenced expressed sequence tags, should provide the entomological, evolutionary biology, medical, and public health communities with useful genetic information.

The molecular through ecological genetics of abnormal abdomen in Drosophila mercatorum. V. Female phenotypic expression on natural genetic backgrounds and in natural environments.

The abnormal abdomen (aa) syndrome in Drosophila mercatorum depends on the presence of R1 inserts in a third or more of the X-linked 28S rDNA genes and the absence of selective underreplication of inserted repeats in polytene tissues that is controlled by an X-linked locus (ur) half a map unit from the rDNA complex. This syndrome affects both life history and morphology in the laboratory. Because abnormal morphologies are rarely encountered in nature, the purpose of this study is to see if the female life history traits are still affected under more natural genetic backgrounds and environmental conditions. Two outbred stocks were extracted from the natural population living near Kamuela, Hawaii: KaaX that has only X chromosomes with uraa alleles, and K+X that has only ur+ alleles. These two stocks have nonoverlapping distributions of insert proportions, indicating strong disequilibrium between the ur locus and the rDNA complex. The KaaX stock had almost no morphological penetrance of uraa, indicating that genetic background is important. KaaX expressed longer female egg-to-adult developmental times, increased early adult female fecundity, and decreased female adult longevity compared with K+X. By bagging natural rots of the cactus Opuntia megacantha near Kamuela, Hawaii, it was shown that egg-to-adult developmental time is slowed down by 0.92 days in females bearing uraa alleles in nature, with no detectable slowdown in uraa males. The bagged rot data also indicate that females bearing uraa alleles have a strong fecundity advantage in nature under some ecological conditions but not others.

Allozyme genotype-environment relationships. I. Variation in natural populations of Drosophila pachea.

Remarkable geographic and seasonal uniformities in gene and genotype frequencies were found for four enzyme loci. Principal component analysis revealed two patterns of allele frequency changes in three of the allozyme loci (Est-b, Est-c and Acph) and one pattern in the Mdh-d locus. These patterns accounted for 90% to 100% of the variability at these loci. Significant positive correlations were obtained between several of the components and the variability in the non-saponifiable and alkaloid fractions of the senita cactus host plant. The genetic variance within a single locality (Guaymas, Mexico) was as great as the variance between all localities sampled. This is interpreted as a local founder effect. The temporary nature of the rotting cactus breeding site, the delayed maturation and the differential maturation rate of females and males are three factors proposed to cause forced outbreeding and counter the local founder effect. A combination of selection resulting from a direct interaction of the genotype and the environment, in addition to migration, is proposed to maintain the uniform gene frequencies.

Temporal and spatial heterogeneity of mtDNA polymorphisms in natural populations of Drosophila mercatorum.

Restriction endonuclease analysis of mtDNA was used to examine the genetic relatedness of several geographically separated isolines of the Drosophila mercatorum subgroup. In addition, we examined the temporal and spatial distribution of two mtDNA restriction site polymorphisms produced by the enzymes BstEII and BstNI at a single locality--Kamuela, Hawaii. Due to small sample sizes of some collections and the undesirable dependance of the estimation of polymorphism frequency on its variance, an arcsin square root transformation of the frequency data was used. We also use an Fst estimator of our transformed frequencies to demonstrate considerable spatial and temporal differentiation within the Kamuela population. In contrast, isozyme data from the same population reveals no pattern of differentiation. The temporal and geographic heterogeneity and population subdivision detected with mtDNA analysis also is consistent with the known dispersal behavior and ecological constraints of this species. The mtDNA data in conjunction with the isozyme data show that the population structure of the Kamuela D. mercatorum is close to the boundary line separating panmixia from subdivision, a conclusion that could not be made from isozyme data alone.

The molecular through ecological genetics of abnormal abdomen. IV. Components of genetic variation in a natural population of Drosophila mercatorum.

Natural populations of Drosophila mercatorum are polymorphic for a phenotypic syndrome known as abnormal abdomen (aa). This syndrome is characterized by a slow-down in egg-to-adult developmental time, retention of juvenile abdominal cuticle in the adult, increased early female fecundity, and decreased adult longevity. Previous studies revealed that the expression of this syndrome in females is controlled by two closely linked X chromosomal elements: the occurrence of an R1 insert in a third or more of the X-linked 28S ribosomal genes (rDNA), and the failure of replicative selection favoring uninserted 28S genes in larval polytene tissues. The expression of this syndrome in males in a laboratory stock was associated with the deletion of the rDNA normally found on the Y chromosome. In this paper we quantify the levels of genetic variation for these three components in a natural population of Drosophila mercatorum found near Kamuela, Hawaii. Extensive variation is found in the natural population for both of the X-linked components. Moreover, there is a significant association between variation in the proportion of R1 inserted 28S genes with allelic variation at the underreplication (ur) locus such that both of the necessary components for aa expression in females tend to cosegregate in the natural population. Accordingly, these two closely linked X chromosomal elements are behaving as a supergene in the natural population. Because of this association, we do not believe the R1 insert to be actively transposing to an appreciable extent. The Y chromosomes extracted from nature are also polymorphic, with 16% of the Ys lacking the Y-specific rDNA marker. The absence of this marker is significantly associated with the expression of aa in males. Hence, all three of the major genetic determinants of the abnormal abdomen syndrome are polymorphic in this natural population.

Delayed radiation necrosis of the brain.

The cases of six patients are presented to delineate the clinical profile of delayed radiation necrosis of the brain. In five the diagnosis was verified histologically. Symptoms most often begin 9 months to 2 years after radiotherapy. Progressive visual impairment and dementia are common following perisellar irradiation, while hemispheric signs predominate following irradiation of the cerebrum. Cerebrospinal fluid protein may be elevated. Focal delta slowing is usually present on electroencephalography. The necrotic brain may appear on radionuclide brain scan as an area of abnormal uptake and also act as an avascular space-occupying lesion. With computerized tomography, radiation necrosis appears as an intracerebral area with diminished absorption coefficient that is often enhanced with intravenous contrast medium. The syndrome may be sufficiently characteristic to eliminate the need for surgical exploration and biopsy in some cases. Cumulative experience suggests that the risk-to-benefit ratio of radiotherapy becomes increasingly unfavorable for most patients with benign intracranial neoplasms when the standard brain tumor dose of 5000 to 7000 rads is fractionated at greater than 200 rads per day.

Behavioral components of dispersal in Drosophila mimica.

In the Hawaiian species, Drosophila mimica, it was necessary to determine the dispersal pattern in order to interpret genetic heterogeneity observed in the population. In addition, the pattern of colonization and speciation in the Drosophila community may have been affected by the dispersal behavior and response to infrequent conditions of environmental factors which would encourage sporadic movement. It was not possible in this experiment to measure such behavior directly, but predictions are possible.Dispersal patterns are formulated in terms of component behavioral responses to particular environmental cues. Under appropriate field measurements, the relationship of behavior patterns of D. mimica to air movement, light, humidity, and food substrate were sufficient to interpret a complex dispersal pattern in the field. Predictions were made for other movement patterns over longer distances and with infrequent occurrence.Present results are explainable by the response of D. mimica to low velocity air currents. Flies move into the current at velocities less than about 3.3 km/hr, and this response is consistent with field observations of insect and air movements. Visible light intensities from more than 10 to about 100 lux were most acceptable to this species, and movement was restricted to light periods.Based upon responses of D. mimica to wind, light, humidity, and attractive areas, long range dispersal would likely occur between two habitats when each had suitable food substrates, the weather was very humid, overcast, and when there was a slight air current between the habitats. Movement would be unidirectional only if air current patterns were stable. The most precise navigation would be at air current velocities below 3.3 km/hr, where olfactory orientation on the substrate in the new habitat would be possible and short flights would be upwind. However, longer range movements would be possible downwind at slightly higher velocities.Genetic data on D. mimica has been interpreted to reflect differences in selection between at least moderately isolated habitats. Our results indicate that, instead of isolated populations, these habitats contain populations that are part of a single deme with sporadic mixing. Genetic heterogeneity may temporarily result from intense localized selection pressure between periods of mixing.Furthermore, the presence of several sibling species (some undescribed) in Kipuka Puaulu and in several neighboring areas clearly illustrates the fragmentation of gene pools and the genetic differentiation which is possible. Since D. mimica might move from one kipuka to another, spatial isolation is unlikely to play a major role in speciation, whereas habitat selection and ethological isolation may be the principal mechanisms of speciation.

Ecological specialization of HawaiianDrosophila : Habitat selection in Kipuka Puaulu.

TheDrosophila community of Kipuka Puaulu, Hawaii Volcanoes National Park, was studied by field measurements and laboratory experiments. Phototactic responses were related to oviposition substrates forD. mimica andD. imparisetae, and were shown to reinforce substrate attractiveness. Both species were associated with rottingSapindus fruit, butD. imparisetae, less light tolerant thanD. mimica, was found in deeper shade. Individuals of a third species,D. kambysellisi, were strongly attracted to substratePisonia leaves. The attraction was strong enough to override strong positive phototaxis. The significance of this behavior was related to the adaptive strategy of the species. The sibling species,D. mimica andD. kambysellisi, utilized different substrates and were strongly separated spatially. Differences in substrates and mobility were related to the "grain size" of their environment. Males ofD. kambysellisi andD. imparisetae are located in leking sites above their respective females during the day. This behavior parallels the relatively greater light tolerance of males than of females. The same light response dimorphism inD. mimica is not accompanied by leking behavior, since they mate at night or in greatly subdued light.

Ecological specialization of HawaiianDrosophila : Habitat selection in Kipuka Puaulu.

TheDrosophila community of Kipuka Puaulu, Hawaii Volcanoes National Park, was studied by field measurements and laboratory experiments. Phototactic responses were related to oviposition substrates forD. mimica andD. imparisetae, and were shown to reinforce substrate attractiveness. Both species were associated with rottingSapindus fruit, butD. imparisetae, less light tolerant thanD. mimica, was found in deeper shade. Individuals of a third species,D. kambysellisi, were strongly attracted to substratePisonia leaves. The attraction was strong enough to override strong positive phototaxis. The significance of this behavior was related to the adaptive strategy of the species. The sibling species,D. mimica andD. kambysellisi, utilized different substrates and were strongly separated spatially. Differences in substrates and mobility were related to the "grain size" of their environment. Males ofD. kambysellisi andD. imparisetae are located in leking sites above their respective females during the day. This behavior parallels the relatively greater light tolerance of males than of females. The same light response dimorphism inD. mimica is not accompanied by leking behavior, since they mate at night or in greatly subdued light.

Thrombophlebitis migrans in association with ulcerative colitis.

A case of thrombophlebitis migrans in a patient with ulcerative colitis is presented. The occurrence of thrombophlebitis was associated with an exacerbation of ulcerative colitis and responded well with the treatment of the underlying colitis. Evidence for a hypercoagulable state in ulcerative colitis is presented.

JSJ-1, an anti-spermidine monoclonal antibody with potential clinical applications.

Polyamines have been implicated in a wide variety of functions including nucleic acid synthesis and protein synthesis. Their levels have been shown to increase in response to cell growth and differentiation. Use of polyamines as prognostic indicators of proliferative disease conditions has been hindered by the lack of suitable rapid and sensitive assays. We report the characterization of an anti-spermidine antibody, JSJ-1, with novel putrescine cross reactivity. JSJ-1 cross-reacts more strongly with putrescine (11%) than with spermine (6%). This suggests that the aminobutyl group common to both putrescine and spermidine is an important element in the antibody-antigen interaction. We have demonstrated that antibody-spermidine binding is effected by increased ionic strength. This finding is consistent with the antibody-antigen interaction being ionic. The JSJ-1 antibody has been successfully used to detect increased polyamine levels in clinical serum samples and identify those with increased polyamine levels.

Genetics of organophosphate resistance in field populations of the house fly (Diptera: Muscidae).

The genetics of resistance to the organophosphate insecticide diazinon were investigated in four populations of the house fly, Musca domestica L., collected in the southern United States. Crosses were made between individual females of lines derived from each population and males of a susceptible strain with three recessive mutants on chromosome II. Individual F1 females were crossed to mutant males, and the progenies were scored for resistance to diazinon and for the presence of mutant phenotypes. A major chromosome II gene for resistance to diazinon was present in all populations at an overall frequency of 83%. Map distances between the resistance gene and the mutant aristapedia and between the mutants aristapedia and stubby wing were highly variable in all populations. Recombination among the visible mutants was usually reduced in resistant progenies relative to susceptible progenies. The data suggest that a single major gene for resistance to diazinon was present on chromosome II in all test populations at variable map positions and is usually associated with a chromosome rearrangement, probably an inversion. The results are similar to those obtained earlier with house fly populations selected for resistance to insecticides in the laboratory; therefore, they seem to be characteristic of field and laboratory populations of the house fly. Overall, the data offer an explanation for previous results suggesting the existence of multiple, closely linked genes for metabolic resistance to insecticides on house fly chromosome II.

Port-access cardiac surgery protocols and early outcomes.

As a new cardiac surgical procedure, port-access holds promise to significantly impact the surgical approaches for treatment of CAD. Supporting collaborative practice protocols contributes to early extubation, rapid in-hospital recovery, and shortened LOS. Discharge protocols address postoperative concerns. Early results suggest that patient recovery is shorter than the time for conventional procedures; patients are able to return to an active lifestyle that is beneficial to families, patients, and employers.

Nietzsche and the dilemma of suffering.

In this paper, we attempt to view a long-held assumption in nursing as mistaken. That is, that patient suffering is something to be overcome. Utilizing Nietzsche's statements on Amor Fati, we carefully examine the cultural assumptions behind our denigration of suffering, look at specific nursing examples of this situation, and attempt the beginnings of a discourse on what it would take for nurses to overcome their own predetermined views of suffering in order to better help their patients "own" their own suffering.