Dawning of the N=32 Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes.

A precision mass investigation of the neutron-rich titanium isotopes ^{51-55}Ti was performed at TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The range of the measurements covers the N=32 shell closure, and the overall uncertainties of the ^{52-55}Ti mass values were significantly reduced. Our results conclusively establish the existence of the weak shell effect at N=32, narrowing down the abrupt onset of this shell closure. Our data were compared with state-of-the-art ab initio shell model calculations which, despite very successfully describing where the N=32 shell gap is strong, overpredict its strength and extent in titanium and heavier isotones. These measurements also represent the first scientific results of TITAN using the newly commissioned multiple-reflection time-of-flight mass spectrometer, substantiated by independent measurements from TITAN's Penning trap mass spectrometer.

Publisher's Note: Isomer Shift and Magnetic Moment of the Long-Lived 1/2

This corrects the article DOI: 10.1103/PhysRevLett.116.182502.

Isomer Shift and Magnetic Moment of the Long-Lived 1/2

Collinear laser spectroscopy is performed on the _{30}^{79}Zn_{49} isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life is confirmed, and the nuclear spins and moments of the ground and isomeric states in ^{79}Zn as well as the isomer shift are measured. From the observed hyperfine structures, spins I=9/2 and I=1/2 are firmly assigned to the ground and isomeric states. The magnetic moment µ (^{79}Zn)=-1.1866(10)µ_{N}, confirms the spin-parity 9/2^{+} with a νg_{9/2}^{-1} shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment µ (^{79m}Zn)=-1.0180(12)µ_{N} supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the N=50 shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state, δ⟨r_{c}^{2}⟩^{79,79m}=+0.204(6) fm^{2}, providing first evidence of shape coexistence.

A Specific and Sensitive Method for the Detection of Colletotrichum lindemuthianum in Dry Bean Tissue.

To facilitate early diagnosis and improve control of bean anthracnose, a rapid, specific, and sensitive polymerase chain reaction (PCR)-based method was developed to detect the causal agent, Colletotrichum lindemuthianum, in bean (Phaseolus vulgaris) seed. Based on sequence data of the rDNA region consisting of the 5.8S gene and internal transcribed spacers (ITS) 1 and 2 of four C. lindemuthianum races and 17 Colletotrichum species downloaded from GenBank, five forward primers were designed and evaluated for their specificity. Among them, one forward primer was selected for use in combination with ITS4 to specifically detect C. lindemuthianum. A 461-bp specific band was amplified from the genomic DNA template of 16 representative isolates of C. lindemuthianum, but not from 58 representative isolates of 17 other Colletotrichum species or 10 bean pathogens. Moreover, to enhance the sensitivity of detection, nested PCR was applied, which allowed the detection of as little as 10 fg of C. lindemuthianum genomic DNA and 1% infected seed powder, which was mixed with 99% healthy seed powder. The diagnostic analysis can be completed within 24 h, compared with about 2 weeks required for culturing. Furthermore, this method can be performed and interpreted by personnel with no specialized taxonomic expertise.

Rap1, a small GTP-binding protein is upregulated during arrest of proliferation in human keratinocytes.

Rap1 is a small GTP-binding protein (SMG) that exists in two 95% homologous isoforms, rap1A and rap1B. The functions of the rap1 proteins are not well understood. In this report we examined expression and function of rap1 in primary (HOKs) and immortalized (IHOKs) human oral keratinocytes under different growth conditions. In HOKs, rap1 increased with passage number, suggesting a role in differentiation and arrest of proliferation. Similarly, when inhibition of proliferation and differentiation were induced in HOKs by 1.2 mM CaCl2, both rap1 and involucrin increased with increasing concentrations of CaCl2. However, when similar experiments were done with IHOKs, which continue to proliferate in the presence of 1.2 mM CaCl2, the increase in involucrin expression was similar to HOKs but there was no substantial increase in rap1, suggesting that increased expression of rap1 is linked to inhibition of proliferation rather than differentiation of keratinocytes. Upon transfection of immortalized keratinocytes with rapGAP, which inactivates both isoforms of endogenous active rap1, enhanced proliferation was observed. Thus, we conclude that rap1 inhibits proliferation in keratinocytes.

Fire and ICE: the role of pyrin domain-containing proteins in inflammation and apoptosis.

The genetic bases for several human autoinflammatory syndromes have recently been identified, and the mutated proteins responsible for these diseases are rapidly being characterized. Here, we examine two of these newly identified proteins, pyrin (also called marenostrin, product of the familial Mediterranean fever locus, MEFV) and cryopyrin (product of the CAIS1 locus, and mutated in familial cold urticaria, Muckle Wells syndrome and chronic infantile neurological cutaneous and articular syndrome). Both pyrin and cryopyrin contain an N-terminal domain that encodes a death domain-related structure, now known as the pyrin domain, or PyD. We trace the molecular interactions mediated by these PyDs, examine the evolution of the family of molecules containing this domain, and discuss the function of PyD-containing proteins and their homologues. Synthesis of the available data indicates that both pyrin and cryopyrin interact via their PyDs with a common adaptor protein, ASC. ASC itself participates in at least three important cellular processes: apoptosis, recruitment and activation of pro-caspase-1 (with associated processing and secretion of IL-1beta), and activation of NF-kappaB (a transcription factor involved in both initiation and resolution of the inflammatory response). Through PyD:PyD interactions, pyrin and cryopyrin, as well as several related, but still uncharacterized PyD containing proteins, appear to modulate the activity of all three of these processes, each of which plays a crucial role in the inflammatory pathways that characterize the innate immune system.

Preliminary phylogeny of Encarsia Förster (Hymenoptera: Aphelinidae) based on morphology and 28S rDNA.

Species of Encarsia Förster (Hymenoptera: Aphelinidae, Coccophaginae) are economically important for the biological control of whitefly and armored scale pests (Hemiptera: Aleyrodidae, Diaspididae). Whereas some regional keys for identification of Encarsia species are now available, few studies have addressed relationships within this diverse and cosmopolitan genus because of unreliable morphological data. Nuclear sequences of the D2 expansion region of 28S rDNA were determined from 67 strains of 24 species representing 10 species groups of Encarsia, 2 strains of Encarsiella noyesi Hayat, and 1 strain of Coccophagoides fuscipennis Girault. Analysis of molecular data alone and combined with morphological data resolves many nodes not resolved by morphology alone and offer insights into which morphological characters are useful for supporting group relationships. All analyses that include molecular data reveal Encarsia to be paraphyletic with respect to Encarsiella. If monophyly of Encarsia is constrained, the relationships are the same but with a different root within Encarsia, and these trees are presented as an alternate hypothesis. The luteola and strenua species groups are shown by both morphological and molecular data to be monophyletic, whereas the inaron group, the E. nigricephala + luteola group, and the E. quericola + strenua group are supported only by molecular data. The aurantii and parvella species groups are not supported in any of the analyses. The utility of morphological characters for defining species group relationships is discussed.

Axons containing the growth associated protein GAP-43 specifically target rat corticotrophs following adrenalectomy.

An extensive network of nerve fibers immunoreactive for the neuronal growth associated protein GAP-43 (GAP-43-IR) is present within the anterior pituitary (AP) of the rat, and the density of these fibers has been reported to increase 4 days after adrenalectomy (ADX). In the present study, we employed confocal dual-label immunofluorescence microscopy to determine whether GAP-43-IR fibers are specifically associated with corticotrophs at various intervals after ADX. A dramatic increase in the density of GAP-43-IR was apparent 4 days after ADX, and this increase was sustained at 7 and 14 days post-ADX. The percentage of corticotrophs in apparent contact with GAP-43-IR axons was 87% at 4 days after ADX and 92% at 14 days. In addition, fewer than 15% of GAP-43-IR terminals were associated with cells other than corticotrophs in either group. This highly specific targeting of corticotrophs during a period in which these cells are undergoing both hypertrophy and hyperplasia indicates that axonal sprouting is occurring in response to ADX. While the less intense GAP-43-IR in the AP of intact rats precluded precise quantitative analysis, the majority of corticotrophs also appeared to be selectively innervated in these animals. The observations that GAP-43-IR axons selectively contact corticotrophs, and that both the specificity and thoroughness of innervation are maintained by targeted growth of GAP-43-IR axons following ADX, strongly suggest that these fibers are of functional significance.

Effects of differential selection in the sexes on cytonuclear dynamics. Life stages with sex differences.

We extend our investigation of cytonuclear selection by determining when differential selection between the sexes will generate allele frequency changes or cytonuclear disequilibria in populations with constant viability selection and an adult census. We demonstrate analytically that there can be a cytonuclear hitchhiking effect upon a selectively neutral marker in either sex provided the other marker is selected in that sex and there is allelic disequilibrium between the loci in females. Cytonuclear disequilibria are generated de novo in both sexes when both loci affect fitness in females and there is a nonmultiplicative fitness interaction between them. Similar fitness interactions in males generate male disequilibria only. Through numerical analyses, we investigate the potential magnitude of such disequilibria, their qualitative dynamics, the expected frequency of detectable disequilibria under particular patterns or strengths of selection, and the possible disequilibrium sign patterns resulting from selection. These adult/viability results subsume those for populations with a gamete census and either constant fertility or viability selection. Although previous work suggests that the disequilibria generated by cytonuclear selection may be difficult to detect experimentally, this study shows that cytonuclear disequilibria at life stages with sex differences can be useful markers of the presence and strength of selection.

Effects of differential selection in the sexes on cytonuclear polymorphism and disequilibria.

We develop a series of models that examine the effects of differential selection between the sexes on cytonuclear polymorphism and disequilibria. A detailed analysis is provided for populations under constant fertility or viability selection censused at life stages without frequency differences in the sexes. We show analytically that cytonuclear disequilibria can be generated de novo if the cytoplasmic and nuclear loci each affect female fitness and there is no nonmultiplicative fitness interaction between them. While computer simulations demonstrate that the majority of disequilibria produced by random selection are transient and small in magnitude, measurable permanent disequilibria can result from selective differences both within and between the two sexes. We derive analytic conditions for a protected cytonuclear polymorphism and use numerical simulations to quantitate the likelihood of obtaining permanent nuclear, cytoplasmic, and cytonuclear variation under various patterns of selection. The numerical analysis identifies special selection regimes more likely to generate disequilibria and maintain cytonuclear polymorphism and reveals a direct correlation to the strength of selection. As a byproduct, our models also provide the first decomposition of the different parental contributions to cytonuclear dynamics and the analytic conditions under which selection can cause cytoplasmic frequency changes or a cytonuclear hitchhiking effect.

Molecular evolution of the Sex-Ratio inversion complex in Drosophila pseudoobscura: analysis of the Esterase-5 gene region.

The Sex-Ratio chromosome in Drosophila pseudoobscura is subject to meiotic drive. It is associated with a series of three nonoverlapping paracentric inversions on the right arm of the X chromosome. The esterase-5 gene region has been localized to section 23 within the subbasal inversion of the Sex-Ratio inversion complex, making esterase-5 a convenient locus for molecular evolutionary analyses of the Sex-Ratio inversion complex and the associated drive system. A 504-bp fragment of noncoding, intergenic DNA from the esterase-5 gene region was amplified and sequenced from 14 Sex-Ratio and 14 Standard X chromosomes of D. pseudoobscura, and from 9 X chromosomes of its two sibling species, Drosophila persimilis and Drosophila miranda. There is extensive sequence differentiation between the Sex-Ratio and Standard chromosomal types. The common Standard chromosome is highly polymorphic, while, as expected from either the neutral mutation theory or the selective sweep hypothesis, the rarer Sex-Ratio chromosome has much less within-chromosome nucleotide polymorphism. We estimate that the Standard and Sex-Ratio chromosomes in D. pseudoobscura diverged between 700,000 and 1.3 Mya, or at least 2 million generations ago. The clustering of D. pseudoobscura Sex-Ratio chromosomes in a neighbor-joining phylogeny indicates a fairly old, monophyletic origin in this species. It appears from these data that Sex-Ratio genes were present prior to the divergence of D. pseudoobscura and D. persimilis and that both the Standard and Sex-Ratio chromosomes of D. persimilis were derived from the Standard chromosome of D. pseudoobscura after the inversion events that isolated the D. pseudoobscura Sex-Ratio chromosome.

Cytoplasmic incompatibility and mating preference in Colombian Drosophila pseudoobscura.

MACRAE and ANDERSON observed a large frequency change of mitochondrial DNA (mtDNA) haplotypes in a population initiated with two allopatric strains of Drosophila pseudoobscura, BogER from Colombia and AH162 from California. They concluded that mtDNA haplotypes in D. pseudoobscura are not always selectively neutral. NIGRO and PROUT suggested, however, that a maternally transmitted incompatibility system, similar to the one they observed in two strains of D. simulans from Italy, could account for the observed mtDNA frequency changes. SINGH and HALE postulated that a mating preference between the strains BogER and AH162 in MACRAF and ANDERSON's experiment, in the form of negative assortative mating, could also account for the mtDNA frequency changes. We report two experiments designed to test the hypotheses: that a maternally transmitted cytoplasmic incompatibility system exists between D. pseudoobscura strains BogER and AH162; and, that BogER females mate preferentially with AH162 males. Our results do not support either hypothesis.

Recurrent gestational trophoblastic disease. Experience of the Southeastern Regional Trophoblastic Disease Center.

Between 1968 and 1985, 28 patients with recurrent gestational trophoblastic disease (GTD) were treated at the Southeastern Regional Trophoblastic Disease Center. Sixteen patients received primary therapy at this center and had recurrence diagnosed by re-elevation of human chorionic gonadotropin (hCG) levels after three consecutive negative levels: five (2.5%) of 204 patients with nonmetastatic GTD, three (3.7%) of 81 with good prognosis metastatic disease, and eight (13%) of 61 with poor prognosis disease. The remaining 12 patients were referred for therapy after receiving primary therapy elsewhere. All episodes of recurrence were observed within 36 months of remission with 50% and 85% before 3 and 18 months, respectively. Fourteen (56%) of 25 patients who achieved secondary remission developed a second recurrence and five (45%) of 11 surviving a second recurrence developed one or more further episodes of recurrent GTD. Nineteen patients (68%) have sustained remission 18 months following therapy for recurrent GTD. Factors relating to development and survival of recurrent disease include: poor prognosis metastatic disease, inadequate initial staging and therapy, lack of adequate maintenance chemotherapy beyond the first negative hCG level, and prolonged intervals between cycles of chemotherapy. Recent regimens introduced have contributed to an increasing salvage rate: 15 of 18 patients treated since 1978 are without evidence of disease whereas only four of ten treated prior to 1978 are currently in remission (P = 0.03).

Individualities in post-serotonin attenuation and Na+/K+ pump activity in vascular smooth muscle.

Prior treatment with serotonin (10(-8)-10(-7) M for 6 min) attenuated responses of rabbit mesenteric arteries to norepinephrine (NE) by 18-62%, but was without effect on the responses of the rabbit aorta. K+ relaxation responses in the mesenteric arteries were enhanced by serotonin, but in the aortic strips K+ relaxation occurred either before or after treatment with serotonin. Maximum relaxation to monensin was similar in the two tissues. Post-serotonin attenuation and K+ and monensin relaxation were blocked by ouabain, indicating that they depended on Na+/K+ pump stimulation. Intracellular Na+ contents (Nai) were determined in the vessels by the Li substitution method. Nai was greater, and was increased to a greater extent by serotonin and K(+)-free physiological salt solution in the mesenteric artery compared to the aorta, suggesting that the cell membrane of the mesenteric artery is leakier to Na+ than is that of the aorta. We conclude that the absence of post-serotonin attenuation in the aorta results from the failure of serotonin to increase Nai and thereby to stimulate the Na+/K+ pump in this tissue. This study demonstrates that important individualities in vascular smooth muscle reactivity even in the same animal may result from differences in membrane permeability to sodium.

Vascular interactions of serotonin and norepinephrine in renal hypertensive rabbits.

Vascular responses to norepinephrine (NE) are potentiated in the presence of serotonin (5-HT) and are attenuated by previous exposure to 5-HT. This study was designed to determine whether alterations in the interactions of these agonists occur in renal hypertension. Helical strips of femoral artery from two-kidney, one clip (2K1C) hypertensive and control rabbits were mounted in muscle baths for isometric force recording. Arterial strips from 2K1C rabbits were more sensitive to 5-HT than were those of control rabbits. The sensitivities of these two groups of vessels to NE were not significantly different. The 5-HT potentiation of NE was present at lower 5-HT concentrations in vessels from 2K1C rabbits than in those from control rabbits. Previous exposure to 5-HT attenuated NE responses of arteries from 2K1C less than it did those of control rabbits. Although 5-HT had little effect on loading of cellular stores of calcium in the resting muscle, previous 5-HT exposure attenuated calcium influx during an NE response, and this attenuation was not as great in vascular smooth muscle from the hypertensive animal as it was in that from the normotensive control. These results indicate that in vascular smooth muscle cells from 2K1C rabbits the potentiating action of 5-HT is increased, due to the increased sensitivity to this agonist, and the attenuating action is decreased due to a greater calcium influx during NE stimulation.

ESR spectroscopy demonstrates that cytochrome b559 remains low potential in Ca (2+)-reactivated, salt-washed PSII particles.

Cytochrome b559 in various Photosystem II preparations was studled by using low temperature ESR spectroscopy. This technique was used because it is able to distinguish high from low potential forms of the cytochrome owing to the g-value differences between these species. Moreover, by using low temperature irradiation to oxidize cyt b559 we have avoided the use of redox mediators. Previous work (Ghanotakis DF., Topper J.N. and Yocum, C.F. (1984) Biochim. Biophys. Acta 767, 524-531) demonstrated that reduction and extraction of manganese of the oxygen evolving complex, which might be expected to alter the redox properties of cyt b559, occurs when certain PSII preparations are exposed to reductants. The ESR data presented here show that a mixture of high potential and lower potential cyt b559 species is observed in the oxygen evolving Photosystem II complex. Treatment of PSII membranes with 0.8 M Tris converts the high potential form(s) to those of lower potential. Exposure of the membranes to 2M NaCl shifts a significant amount of high potential cyt b559 to lower potential form(s); addition of CaCl2 reconstituted oxygen evolution activity but did not restore cyt b559 to its high potential form(s).

Ascertainment of vital status through the National Death Index and the Social Security Administration.

Ascertainment of the vital status of individuals is of central importance to epidemiologic studies which monitor mortality as an end point. Utilizing identifying information collected in 1973-1974, the Hypertension Detection and Follow-up Program, a prospective, multicenter study, followed 25,362 individuals to determine eight-year mortality. In the most recent follow-up, there were 617 individuals whose vital status was not known. Available identifying information on these and on all 1,322 participants known to have died in 1979-1981 was submitted to the National Death Index (NDI) for possible confirmation of vital status. A subset of individuals who had Social Security numbers (490 lost to follow-up and 1,154 known deaths) was also submitted to the Social Security Administration (SSA). The NDI correctly identified 87.0% of the known deaths. Of the 1,154 known deaths (those with known Social Security numbers) submitted to both agencies, the NDI identified 93.1% and the SSA 83.6%. Significant variations by race and sex were noted in the identification rates, in part because of Social Security number discrepancies. False matches through the NDI matching process occurred for 10.4% of the known deaths. In the more restrictive SSA search, only 0.5% false matches resulted. For those lost to follow-up, vital status was ascertained in 57.1%. This paper describes the relative efficacy and attributes of the use of these systems to ascertain vital status.