Breed Locally,Disperse Globally: Fine-Scale Genetic Structure Despite Landscape-Scale Panmixia in a Fire-Specialist

An exciting advance in the understanding of metapopulation dynamics has been the investigation of how populations respond to ephemeral patches that go ‘extinct’ during the lifetime of an individual. Previous research has shown that this scenario leads to genetic homogenization across large spatial scales. However, little is known about fine-scale genetic structuring or how this changes over time in ephemeral patches. We predicted that species that specialize on ephemeral habitats will delay dispersal to exploit natal habitat patches while resources are plentiful and thus display fine-scale structure. To investigate this idea, we evaluated the effect of frequent colonization of ephemeral habitats on the fine-scale genetic structure of a fire specialist, the black-backed woodpecker (Picoides arcticus) and found a pattern of fine-scale genetic structure. We then tested for differences in spatial structure between sexes and detected a pattern consistent with male-biased dispersal. We also detected a temporal increase in relatedness among individuals within newly burned forest patches. Our results indicate that specialist species that outlive their ephemeral patches can accrue significant fine-scale spatial structure that does not necessarily affect spatial structure at larger scales. This highlights the importance of both spatial and temporal scale considerations in both sampling and data interpretation of molecular genetic results.     

Molecular and Genetic Characterization of the Drosophila tartan Gene

Here we report the discovery and characterization of the Drosophila tartan gene tartan is transcribed in an unusual embryonic pattern of intersecting stripes which are generated in response to the anterior-posterior and dorsal-ventral regulatory systems. tartan encodes a putative transmembrane protein containing extracellular leucine-rich repeats characteristic of numerous cell surface receptors and adhesion proteins. Its expression is correlated with aspects of segmentation and neurogenesis, including the formation of neuroblasts, sensory mother cells, and peripheral nerves. Mutants homozygous for a recessive lethal tartan loss-function allele exhibit defects in the position and number of cells within peripheral sense organs, the routing of peripheral nerves, and the organization of commissures within the central nervous system. Mutants are also defective in muscle organization. These results suggest that tartan is required for cell surface interactions important for normal organization of epidermal and subepidermal structures.     

Lignified cells in Lilium longiflorum Thunb. styles and their relation to bioelectric potential changes

Ludwigia perennis L. infected with rice necrosis mosaic virus (RNMV) showed an increase in both shoot growth and leaf size, along with characteristic chlorotic lesions on leaves. The promotion of growth over the controls extended over a considerable period of time (70 d). Inoculation with RNMV resulted in increased plant height, leaf size, stem diameter, and number and size of fiber bundles in Corchorus olitorius L., C. capsularis L., Hibiscus sabdariffa L. and H. cannabinus L.Abbreviation RNMV rice necrosis mosaic virus     

Cerebrospinal fluid miRNA profile in HIV‐encephalitis

MicroRNAs are short non‐coding RNAs that modulate gene expression by translational repression. Because of their high stability in intracellular as well as extracellular environments, miRNAs have recently emerged as important biomarkers in several human diseases. However, they have not been tested in the cerebrospinal fluid (CSF) of HIV‐1 positive individuals. Here, we present results of a study aimed at determining the feasibility of detecting miRNAs in the CSF of HIV‐infected individuals with and without encephalitis (HIVE). We also evaluated similarities and differences between CSF and brain tissue miRNAs in the same clinical setting. We utilized a high throughput approach of miRNA detection arrays and identified differentially expressed miRNAs in the frontal cortex of three cases each of HIV+, HIVE, and HIV? controls, and CSF of 10 HIV‐positive and 10 HIV‐negative individuals. For the CSF samples, the group of HIV+ individuals contained nine cases of HIV‐associated neurological disorders (HAND) and, among those, four had HIVE. All the HIV‐negative samples had non‐viral acute disseminate encephalomyelitis. A total of 66 miRNAs were found differentially regulated in HIV+ compared to HIV? groups. The greatest difference in miRNA expression was observed when four cases of HIVE were compared to five non‐HIVE cases, previously normalized with the HIV‐negative group. After statistical analyses, 11 miRNAs were fund significantly up‐regulated in HIVE. Although more clinical samples should be examined, this work represents the first report of CSF miRNAs in HIV‐infection and offers the basis for future investigation. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.     

Arrangement of trichokeratin intermediate filaments and matrix in the cortex of Merino wool

Tomograms of transverse sections of Merino wool fibers obtained from fleeces differing in fiber curvature were reconstructed from image series collected using a 300 kV transmission electron microscope. Trichokeratin intermediate filaments (IFs) from the ortho-, para- and mesocortices were modeled from the tomograms. IFs were predominantly arranged in left-handed concentric helices with the relative angle of IFs increasing progressively from the center to the periphery of orthocortex macrofibrils. The median increase in IF angle between adjacent IFs between the center and periphery was 2.5°. The length of one turn of the helical path of an IF was calculated to be approximately 1 μm for an IF tilted at 30° and positioned 100 nm from the macrofibril center. With the exception of one paracortex macrofibril that weakly resembled an orthocortex macrofibril, all para- and mesocortex macrofibrils modeled had a parallel arrangement of the IFs, with a more ordered arrangement found in the mesocortex. Within the limited sample set, there appeared to be no significant relationship between IF angle and fiber curvature. We examined the matrix/IF ratio (in the form of proportion of matrix to one IF, calculated from IF center-to-center distance and IF diameter) for 28 macrofibrils used for modeling. The proportion of matrix was significantly different in the different cortex cell types, with paracortex having the most (0.61), orthocortex having the least (0.42), and mesocortex being intermediate (0.54). Fibers of different crimp type (high, medium or low crimp) were not significantly different from each other with respect to matrix proportion.     

Myeloablative Temozolomide Enhances CD8+ T-Cell Responses to Vaccine and Is Required for Efficacy against Brain Tumors in Mice

Temozolomide (TMZ) is an alkylating agent shown to prolong survival in patients with high grade glioma and is routinely used to treat melanoma brain metastases. A prominent side effect of TMZ is induction of profound lymphopenia, which some suggest may be incompatible with immunotherapy. Conversely, it has been proposed that recovery from chemotherapy-induced lymphopenia may actually be exploited to potentiate T-cell responses. Here, we report the first demonstration of TMZ as an immune host-conditioning regimen in an experimental model of brain tumor and examine its impact on antitumor efficacy of a well-characterized peptide vaccine. Our results show that high-dose, myeloablative (MA) TMZ resulted in markedly reduced CD4⁺, CD8⁺ T-cell and CD4⁺Foxp3⁺ T_Reg counts. Adoptive transfer of naïve CD8⁺ T cells and vaccination in this setting led to an approximately 70-fold expansion of antigen-specific CD8⁺ T cells over controls. Ex vivo analysis of effector functions revealed significantly enhanced levels of pro-inflammatory cytokine secretion from mice receiving MA TMZ when compared to those treated with a lower lymphodepletive, non-myeloablative (NMA) dose. Importantly, MA TMZ, but not NMA TMZ was uniquely associated with an elevation of endogenous IL-2 serum levels, which we also show was required for optimal T-cell expansion. Accordingly, in a murine model of established intracerebral tumor, vaccination-induced immunity in the setting of MA TMZ–but not lymphodepletive, NMA TMZ–led to significantly prolonged survival. Overall, these results may be used to leverage the side-effects of a clinically-approved chemotherapy and should be considered in future study design of immune-based treatments for brain tumors.     

Biochemical evidence for structurally distinct H-2Dd antigens differing in serological properties

H-2D^d antigens, as defined by the private H-2.4 determinant, exist as two immunochemically distinct populations in H-2^a and H-2^dm2 splenocytes and in the transformed cell line, RADA1(H-2 ^a). The two populations are distinguishable by the anti-H-2.28 serum, k/r anti-h2, which is directed, in part, against the H-2.28 family of public determinants encoded by the D end of the b haplotype. Sequential precipitates of lentil-lectin-purified glycoprotein extracts metabolically labeled with radioactive amino acids reveal that approximately one-quarter to one-third of the H-2D^d antigens, designated H-2D^d (b28 ⁺), react with this antiserum, whereas two-thirds to three-quarters, designated H-2D^d(b28^–), do not. Paired-label tryptic peptide maps in this and a previous study indicate that H-2D^d(b28⁺) and H-2D^d(b28 ^–) are closely related structurally and are more likely to represent modified forms of the same gene product rather than products of different genes, although the existence of closely related genetic loci is not rigorously excluded. Together, H-2D^d(b28⁺) and H-2D^d(b28^–) have a radioactivity level seven times higher than H-2L^d, which also reacts with the anti-H-2.28 serum but which lacks the H-2.4 determinant. As yet unresolved, however, is the question of whether the observed quantitative differences between these three antigens reflect actual molar differences at the cellular level, or whether the variation is the result of metabolic or compositional factors. In any case, a complex serological and structural relationship is found to exist between antigens encoded by the D/L end of the MHC.     

The Reporting of Cytologic Smears—Selected Problems with Morphologic Terms

Problems arise when morphologic terminology falls into categories which: (1) Utilize numbers to replace words and (2) utilize words of such indeterminate meaning that definition depends entirely upon local usage.We should strive to replace any means of diagnosis that does not convey specificity with means capable of precision. The major criterion for the suitability of a diagnostic system is that it is universally understood and is precise enough to result in optimal patient management. Meeting those demands requires the use of nomenclature in cytology that approximates, as far as possible, the actual tissue diagnosis.