Developmental Nutrition Affects the Structural Integrity of a Sexually Selected Weapon.

Males in many species engage in physical combat over access to mates, and sexual selection has led to the evolution of weapons to enhance contest performance. The size of these often-elaborate structures is known to be exquisitely sensitive to nutrition. However, we know very little about the degree to which nutrition affects other attributes of animal weapons that can be crucial to fighting. In this study, we investigated the impact of natural dietary variation on weapon structural integrity in a fighting insect, Narnia femorata (Hemiptera: Coreidae). Males in this species display their enlarged, spiny hind legs to other males, and these legs serve as weapons in aggressive physical contests where they are used to strike and squeeze opponents. N. femorata feeds on the fruit of prickly pear cactus and sets up territories on this plant. In North Central Florida the prickly pear Opuntia mesacantha ssp. lata blooms and begins to produce fruits in April and May. N. femorata has multiple, overlapping generations while the green fruits slowly ripen over the next several months. We examined insects reaching adulthood at two nearby time points in this range, June and July, to test the influence of the nutrition provided by ripening green cactus fruit on weapon size and its ability to resist puncture. We also raised insects on cactus with red, ripe fruit for comparison. We found a striking effect of cactus fruit phenology on weapons. Insects raised with the more mature green fruit (those in the second cohort) had 71% larger weapon area and 4.4 times greater puncture resistance than those raised on the early green fruit (those in the first cohort). In contrast, insects raised on red, ripe fruit were moderate in size, had high puncture resistance, and they changed little phenotypically from the first to second cohort. Increased structural integrity of the hind femur weapon was associated with the increased body size that came with better nutrition. This pattern highlights that cuticle thickness increased or its material properties changed when weapons were larger. Importantly, effects of nutrition on puncture resistance also transcended size. Insects of the same size had greater structural integrity if they received superior nutrition. Sexually selected weapons are often used as visual signals to conspecifics before fights, and this work hints that the size of the weapons may be a poor signal of weapon performance when nutrition is variable.

Experimental manipulation reveals a trade-off between weapons and testes.

Theory predicts a trade-off between sexually selected weapons used to secure mates and post-copulatory traits used to maximize fertilization success. However, individuals that have a greater capacity to acquire resources from the environment may invest more in both pre- and post-copulatory traits, and trade-offs may not be readily apparent. Here, we manipulate the phenotype of developing individuals to examine allocation trade-offs between weapons and testes in Mictis profana (Hemiptera: Coreidae), a species where the hind legs are sexually selected weapons used in contests over access to females. We experimentally prevented males from developing weapons by inducing them to autotomize their hind legs before the final moult to adulthood. We compared trait expression in this group to males where autotomy was induced in the mid-legs, which are presumably not under sexual selection to the same extent. We found males without weapons invested proportionally more in testes mass than those with their mid-legs removed. Males that developed to adulthood without weapons did not differ from the mid-leg removal group in other traits potentially under precopulatory sexual selection, other post-copulatory traits or naturally selected traits. In addition, a sample of adult males from the same population in the wild revealed a positive correlation between investment in testes and weapons. Our study presents a critical contribution to a growing body of literature suggesting the allocation of resources to pre- and post-copulatory sexual traits is influenced by a resource allocation trade-off and that this trade-off may only be revealed with experimental manipulation.

The tale of the shrinking weapon: seasonal changes in nutrition affect weapon size and sexual dimorphism, but not contemporary evolution.

Sexually selected traits are often highly variable in size within populations due to their close link with the physical condition of individuals. Nutrition has a large impact on physical condition, and thus, any seasonal changes in nutritional quality are predicted to alter the average size of sexually selected traits as well as the degree of sexual dimorphism in populations. However, although traits affected by mate choice are well studied, we have a surprising lack of knowledge of how natural variation in nutrition affects the expression of sexually selected weapons and sexual dimorphism. Further, few studies explicitly test for differences in the heritability and mean-scaled evolvability of sexually selected traits across conditions. We studied Narnia femorata (Hemiptera: Coreidae), an insect where males use their hind legs as weapons and the femurs are enlarged, to understand the extent to which weapon expression, sexual dimorphism and evolvability change across the actual range of nutrition available in the wild. We found that insects raised on a poor diet (cactus without fruit) are nearly monomorphic, whereas those raised on a high-quality diet (cactus with ripe fruit) are distinctly sexually dimorphic via the expression of large hind leg weapons in males. Contrary to our expectations, we found little evidence of a potential for evolutionary change for any trait measured. Thus, although we show weapons are highly condition dependent, and changes in weapon expression and dimorphism could alter evolutionary dynamics, our populations are unlikely to experience further evolutionary changes under current conditions.

Scaling law for electrocaloric temperature change in antiferroelectrics.

A combination of theoretical and first-principles computational methods, along with experimental evidence from the literature, were used to predict the existence of a scaling law for the electrocaloric temperature change in antiferroelectric materials. We show that the temperature change scales quadratically with electric field, allowing a simple transformation to collapse the set of ΔT(E) onto a single curve. This offers a unique method that can be used to predict electrocaloric behavior beyond the limits of present measurement ranges or in regions where data are not yet available.

How neuroscience relates to hearing aid amplification.

Hearing aids are used to improve sound audibility for people with hearing loss, but the ability to make use of the amplified signal, especially in the presence of competing noise, can vary across people. Here we review how neuroscientists, clinicians, and engineers are using various types of physiological information to improve the design and use of hearing aids.

Multi-frame super-resolution algorithm for complex motion patterns.

Multi-frame super-resolution algorithms offer resolution enhancement for sequences of images with sampling limited resolution. However, classical approaches have been constrained by the accuracy of motion estimation while nonlocal approaches that use implicit motion estimation have attained only modest resolution improvement. In this paper, we propose a new multi-frame optical flow based super-resolution algorithm, which provides significant resolution enhancement for image sequences containing complex motion. The algorithm uses the standard camera image formation model and a variational super-resolution formulation with an anisotropic smoothness term adapting to local image structures. The key elements enabling super-resolution of complex motion patterns are the computation of two-way optical flow between the images and use of two corresponding uncertainty measures that approximate the optical flow interpolation error. Using the developed algorithm, we are able to demonstrate super-resolution of images for which optical flow estimation experiences near breakdown, due to the complexity of the motion patterns and the large magnitudes of the displacements. In comparison, we show that for these images some conventional super-resolution approaches fail, while others including nonlocal super-resolution technique produce distortions and provide lower (1-1.8 dB) image quality enhancement compared to the proposed algorithm.

The form of sexual selection arising from male-male competition depends on the presence of females in the social environment.

Sexual selection arises from social interactions, and if social environments vary so too should sexual selection. For example, male-male competition often occurs either in the presence or in the absence of females, and such changes in the social environment could affect the form and strength of sexual selection. Here we examine how the presence of a female influences selection arising from male-male competition in a leaf-footed cactus bug, Narnia femorata, which has a resource defence mating system. Males compete for territories on cacti because females lay eggs on the cactus plants. Females are not always present when this competition first occurs; however, the presence or absence of the female matters. We found that both the form and strength of selection on male traits, those traits that influenced success in intrasexual competition, depended on the social context. When a female was not present, male size and the area of the sexually dimorphic hind legs was only marginally important to winning a contest. However, males with larger overall size and leg area were more likely to win in the presence of a female. There was also positive quadratic selection on these traits when a female was present with both the largest and the smallest males winning. The implication is unexpected alternative strategies when females are present. Our results support the notion that sexual selection should be studied under all relevant social contexts.

DLK1: increased expression in gliomas and associated with oncogenic activities.

DLK1 (delta-like) is a transmembrane and secreted protein in the epidermal growth factor-like homeotic family. Although expressed widely during embryonic development, only a few tissues retain the expression in adults. Neuroendocrine tumors often highly express this protein; therefore, we hypothesized that brain tumors might also express it. This study found that the expression of DLK1 in gliomas was higher than that in normal brain (P < 0.05). After stable transfection of a DLK1 cDNA expression vector into GBM cell lines, their proliferation was increased. Furthermore, they lost contact inhibition, had enhanced anchorage-independent growth in soft agar, and had significantly greater capacity to migrate. Western blot studies showed that expression of cyclin D1, CDK2, and E2F4 were increased, and Rb levels were decreased in these cells. DLK1 was found on the cell surface and secreted in the medium from the transfected GBM cells. DLK1-enriched condition medium stimulated the growth of glioblastoma multiforme cell lines and explants. DLK1 antibody blocked cell growth stimulated by DLK1. In summary, these results suggest that DLK1 may play a role in the formation or progression of gliomas.

Dlk1 in normal and abnormal hematopoiesis.

Dlk1 (Pref-1) is a transmembrane and secreted protein, which is a member of the epidermal growth factor-like family, homologous to Notch/Delta/Serrate. We have found by real-time RT-PCR that Dlk1 mRNA levels were high in CD34(+) cells in 10 of 12 MDS samples compared with CD34(+) cells from 11 normals. Also, Dlk1 mRNA was elevated in mononuclear, low density bone marrow cells from 11/38 MDS patients, 5/11 AML M6 and 2/4 AML M7 samples. Furthermore, 5/6 erythroleukemia and 2/2 megakaryocytic leukemia cell lines highly expressed Dlk1 mRNA. Levels of Dlk1 mRNA markedly increased during megakaryocytic differentiation of both CMK megakaryoblasts as well as normal CD34(+) hematopoietic stem cells. High serum levels of Dlk1 occurred in RA (4/10) and essential thrombocythemia (2/10) patients. Functional studies showed that forced expression of Dlk1 enhanced proliferation of K562 cells growing in 1% fetal bovine serum. Analysis of hematopoiesis of Dlk1 knockout mice suggested that Dlk1 contributed to granulocyte, megakaryocyte and B-cell clonogenic growth and was needed for generation of splenic B-cells. In summary, Dlk1 is overexpressed in selected samples of MDS (especially RA and RAEB) and AML (particularly M6, M7), and it appears to be associated with normal development of megakaryocytes and B cells.

Triboelectric simulation of pacemaker malfunction.

We report the occurrence of a triboelectric phenomenon (static electricity) that mimicked malfunction of a contemporary pacemaker by creating an electrocardiograpic artifact virtually identical to the pacemaker stimuli. The diagnosis was established by observing a subtle overshoot of the questionable deflection that was absent from pacemaker stimuli.

Evaluation of accuracy and reliability of indirect calorimetry for the measurement of resting energy expenditure in healthy dogs.

OBJECTIVE: To assess accuracy and reliability of open-flow indirect calorimetry in dogs. ANIMALS: 13 clinically normal dogs. PROCEDURE: In phase 1, oxygen consumption per kilogram of body weight (VO2/kg) was determined in 6 anesthetized dogs by use of open-flow indirect calorimetry before and after determination of VO2/kg by use of closed-circuit spirometry. In phase 2, four serial measurements of VO2 and carbon dioxide production (VCO2) were obtained in 7 awake dogs by use of indirect calorimetry on 2 consecutive days. Resting energy expenditure (REE) was calculated. RESULTS: Level of clinical agreement was acceptable between results of indirect calorimetry and spirometry. Mean VO2/kg determined by use of calorimetry before spirometry was significantly greater than that obtained after spirometry. In phase 2, intraclass correlation coefficients (ICC) for REE and VO2 were 0.779 and 0.786, respectively, when data from all 4 series were combined. When the first series was discounted, ICC increased to 0.904 and 0.894 for REE and VO2, respectively. The most reliable and least variable measures of REE and VO2 were obtained when the first 2 series were discounted. CONCLUSIONS AND CLINICAL RELEVANCE: Open-flow indirect calorimetry may be used clinically to obtain a measure of VO2 and an estimate of REE in dogs. Serial measurements of REE and VO2 in clinically normal dogs are reliable, but a 10-minute adaption period should be allowed, the first series of observations should be discounted, multiple serial measurements should be obtained, and REE.

Analysis of the CHK2 gene in lymphoid malignancies.

The CHK2 gene encodes a protein kinase that is important for the regulation of cell cycle arrest after DNA damage. CHK2 acts downstream of ataxia teleangiecstasia mutated (ATM), modulates the function of p53 and may help mediate cell cycle arrest at G2/M by phosphorylation of Cdc25C. Recently, the human homolog of the checkpoint kinase Cds1 (CHK2) has been suggested to be a tumor suppressor gene. Heterozygous germline mutations have been reported in Li-Fraumeni syndrome (LFS), a highly penetrant familial cancer phenotype, and in sporadic colon cancer. LFS is associated with the development of lymphoid malignancies, especially childhood ALL. Therefore, we analyzed the DNA from 143 lymphoid malignancies to determine whether they had mutations of the CHK2 gene. The 14 exons of CHK2 were studied by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and sequencing of aberrantly migrating bands. One missense mutation changing serine to phenylalanine (codon 428) in an evolutionarily highly conserved domain was found in a non-Hodgkin's aggressive lymphoma. Another point mutation in the non-coding region was identified in one of adult T-cell leukemias (ATL) samples. This result suggests that mutation of the CHK2 gene may rarely be involved in the development of selected lymphomas.

Cyr61, a member of CCN family, is a tumor suppressor in non-small cell lung cancer.

Cysteine-rich protein 61 (Cyr61) is a member of a family of growth factor-inducible immediate-early genes. It regulates cell adhesion, migration, proliferation, and differentiation and is involved in tumor growth. In our experiments, the role of Cyr61 in non-small cell lung cancer (NSCLC) was examined. Expression of Cyr61 mRNA was decreased markedly in four of five human lung tumor samples compared with their normal matched lung samples. NSCLC cell lines NCI-H520 and H460, which have no endogenous Cyr61, formed 60-90% fewer colonies after being transfected with a Cyr61 cDNA expression vector than cells transfected with the same amount of empty vector. After stable transfection of a Cyr61 cDNA expression vector, proliferation of both H520-Cyr61 and H460-Cyr61 sublines decreased remarkably compared with the cells stably transfected with empty vector. The addition of antibody against Cyr61 partially rescued the growth suppression of both H520-Cyr61 and H460-Cyr61 cells. Cell cycle analysis revealed that both H520-Cyr61 and H460-Cyr61 cells developed G(1) arrest, prominently up-regulated expression of p53 and p21(WAF1), and had decreased activity of cyclin-dependent kinase 2. The increase of pocket protein pRB2/p130 was also detected in these cells. Notably, both of the Cyr61-stably transfected lung cancer cell lines developed smaller tumors than those formed by the wild-type cells in nude mice. Taken together, we conclude that Cyr61 may play a role as a tumor suppressor in NSCLC.

Dietary chloride as a possible determinant of the severity of exercise-induced asthma.

Dietary sodium chloride (NaCl) has been shown to alter the severity of exercise-induced asthma, but it is not known if the sodium and chloride ions have independent effects in this regard. The hypothesis tested in the present study was that both a low sodium, low chloride diet and a high sodium, low chloride diet would improve post-exercise pulmonary function in subjects with exercise-induced asthma (EIA) compared to a normal NaCl diet (NSD); but that neither of these diets would have an effect on post-exercise pulmonary function in control (non-EIA) subjects. Eight subjects who suffered from EIA and eight subjects who did not (control) took part in a double-blind crossover study. Pre- and post-exercise pulmonary function was assessed after 2 weeks on a NSD, a low NaCl diet (LSD, low sodium, low chloride) or a sodium bicarbonate diet (NaHCO3 diet, high sodium, low chloride). A 1 week washout period occurred between diets. Altering dietary sodium or chloride had no effect on pre-exercise (baseline) pulmonary function in either group or on post-exercise pulmonary function in control subjects. However, both the LSD and the NaHCO3 diet lessened the deterioration in post-exercise pulmonary function in EIA subjects. Comparing results from pre- to post-exercise, forced expiratory volume in 1 s (FEV1) at 15 min post-exercise differed significantly (P < 0.05) between diets [mean (SEM) 7 (4)% on the LSD, 14 (4)% on the NaHCO3 diet, and 19 (2)% on the NSD]. Similar patterns were observed for forced vital capacity (FVC), forced expiratory flow rate at 25%-75% FVC and peak expiratory flow rate. The NaHCO3 diet lessened the deterioration of post-exercise pulmonary function, but not to the extent of LSD. These data suggest that both sodium and chloride contribute to the worsening of EIA symptoms seen after consuming a normal or high NaCl diet.

Frequent loss of heterozygosity in the region of D1S450 at 1p36.2 in myelodysplastic syndromes.

To understand the underlying mechanisms in myelodysplastic syndromes (MDS) by identifying target tumor suppressor genes, we performed a detailed deletional mapping of the short arm of chromosome 1 in 38 paired samples of bone marrow and peripheral blood obtained from individuals with MDS by PCR amplification of a total of 23 highly informative microsatellite sequences. We identified the commonly deleted region between D1S508 and D1S244. LOH of this region was found in five patients (13%). In addition, LOH at 1p was associated with a poor clinical outcome, suggesting that the deletion of a gene in this region may be involved in the course of this disease. By analyzing the chromosomal map of this region, we found TNFRSF12 as a candidate tumor suppressor gene. However, our search for mutations in this gene did not identify somatic mutations in MDS. Our findings are consistent with the possible existence of an as-yet unknown tumor suppressor gene in this region that is altered in MDS.

Mutational analysis of the peroxisome proliferator-activated receptor gamma gene in human malignancies.

Peroxisome proliferator-activated receptor gamma (PPARgamma) plays an important role in adipocyte differentiation and is expressed in many human malignancies, including those from prostate, breast, as well as colon. It regulates differentiation and/or cell growth of these cells. However, expression of this nuclear hormone receptor in other types of cancer, especially in hematological malignancies, remains to be fully elucidated. The PPARgamma gene has been mapped to chromosome band 3p25, where chromosomal abnormalities are observed in a variety of human malignancies. Furthermore, a recent study revealed that the PPARgamma gene is functionally mutated in sporadic colon cancer cells. Therefore, PPARgamma could be an important tumor suppressor gene. This prompted us to investigate the expression and mutational status of the PPARgamma gene in cancers of a variety of tissues. A total of 159 samples were interrogated for their expression of PPARgamma as measured by reverse transcription-polymerase chain reaction and/or Western blot analysis. In each of the samples, expression of PPARgamma was detectable. In addition, a total of 397 clinical samples and cell lines including colon, prostate, breast and lung cancers, and leukemias were analyzed for mutations of the PPARgamma gene by either reverse transcription-polymerase chain reaction-single-strand conformation polymorphism or polymerase chain reaction-single-strand conformation polymorphism analysis. No abnormalities were detectable in any of the human malignancies. On the other hand, shifted bands were easily detectable when using positive controls, which harbored the same sequence alterations reported previously in colon cancer cells. Taken together, PPARgamma is expressed in a variety of cancers, and mutation of the PPARgamma gene is a very rare event in human malignancies.

Mutations in the mitotic check point gene, MAD1L1, in human cancers.

Aneuploidy is a characteristic of the majority of human cancers, and recent studies suggest that defects of mitotic checkpoints play a role in carcinogenesis. MAD1L1 is a checkpoint gene, and its dysfunction is associated with chromosomal instability. Rare mutations of this gene have been reported in colon and lung cancers. We examined a total of 44 cell lines (hematopoietic, prostate, osteosarcoma, breast, glioblastoma and lung) and 133 fresh cancer cells (hematopoietic, prostate, breast and glioblastoma) for alterations of MAD1L1 by RT-PCR-SSCP and nucleotide sequencing. Eight mutations consisting of missense, nonsense and frameshift mutations were found, together with a number of nucleotide polymorphisms. All the alterations in cell lines were heterozygous. Frequency of mutations was relatively high in prostate cancer (2/7 cell lines and 2/33 tumor specimens). We placed a mutant truncated MAD1L1, found in a lymphoma sample, into HOS, Ht161 and SJSA cell lines and found that it was less inhibitory than wild type MAD1L1 at decreasing cell proliferation. Co-expression experiments showed that the mutant form had a dominant-negative effect. Furthermore, this mutant impaired the mitotic checkpoint as shown by decreased mitotic indices in HOS cells expressing mutant MAD1L1 after culture with the microtubule-disrupting agent, nocodazole. Our results suggest a pathogenic role of MAD1L1 mutations in various types of human cancer.

Closed reduction of a dislocation of a constrained acetabular component.

A constrained acetabular liner occasionally is used in management of chronic instability after total hip arthroplasty. If dislocation occurs out of a constrained liner, open reduction is indicated. A case is presented of closed reduction of a femoral component into a constrained liner.