GC Population Research Articles

Quantification of Rat Spermatogenesis in Late Puberty after Neonatal Hormonal Manipulation

ABSTRACTIt has been known for many years that estrogens administration to experimental animals during the neonatal period or adulthood can impair sperm production and maturation. In earlier studies the negative effects of E were explained only as a result of suppression of gonadotropin secretion during the treatment. We aimed to assess GC development on day 35 (different GC types) in tandem with Sertoli cell support toward GCs (efficiency of spermatogenesis) by complex systems of quantitative criteria. We used experimental model for manipulation of neonatal hormonal environment by treatment with DES-10 μg, DES-1 μg, DES-0.1 μg or GnRHa. DES-10 greatly affected testis development and spermatogenesis in rat whereas GnRHa was quite less effective in producing negative impact. In contrast during the onset of puberty (d 18) both treatments exerted similar negative effect, and this time dependent response of the testis corresponds to different hormonal profiles. Quantitative evaluation of late pubertal spermatogenesis demonstrate that the most differentiated GC population- spermatides was the most sensitive to hormonal manipulation compared to spermatogonia (Sg) and spermatocytes (Sc). Different mechanisms are probably involved in mediation of the effect of E and gonadotropins and direct E action on GC differentiation is suggested. Our finding would elucidate our understanding about the hormonal regulation of different germ sell steps of spermatogenesis.

Globular cluster system erosion in elliptical galaxies

In this paper we analyze data of 8 elliptical galaxies in order to study the difference between their globular cluster systems (GCSs) radial distributions and those of the galactic stellar component. In all the galaxies studied here the globular cluster system density profile is significantly flatter toward the galactic centre than that of stars. If this difference is interpreted as a depauperation of the initial GC population, the estimated number of missing globular clusters is significant, ranging from 21% to 71% of their initial population abundance in the eight galaxies examined. The corresponding mass lost to the central galactic region is 7x10^7-1.85x10^9 solar masses. All this mass carried toward central galactic regions have likely had an important feedback on the innermost galactic region, including its violent transient activity (AGN) and local massive black hole formation and growth.

THE GLOBULAR CLUSTER SYSTEM IN M87: A WIDE-FIELD STUDY WITH CFHT/MEGACAM

CFHT Megacam data in (g',r',i') are used to obtain deep, wide-field photometry of the globular cluster system (GCS) around M87. A total of 6200 GCs brighter than M_I = -8.5 are included in the study, essentially containing almost the entire bright half of the total GC population in the galaxy. The classic bimodal metal-poor and metal-rich sequences of GCs show up clearly; while the spatial distribution of the GCs can be traced detectably outward to more than 100 kpc, the blue, metal-poor subpopulation is very much more spatially extended than the red subpopulation. Both the red and blue GC subsystems have radial metallicity gradients, where mean heavy-element abundance scales with projected galactocentric distance as Z ~ R^{-0.12} (blue) and R^{-0.17} (red). The blue sequence exhibits a strongly significant mass/metallicity relation (MMR) in which the mean metallicity gradually increases with cluster luminosity as Z ~ L^{0.25 \pm 0.05} for the luminosity range M_I < -10. However, this relation is also clearly nonlinear, becoming vertical at fainter levels. The MMR can be understood as the result of self-enrichment within the most massive metal-poor GCs during their formation. In giant elliptical galaxies, the red GCs are likely to represent a broad composite population formed during several major starbursts. If so, the red sequence might display a population-based MMR that could in principle be either positive or negative.

The globular clusters-stellar haloes connection in early-type galaxies

This paper explores if, and to what an extent, the stellar populations of early type galaxies can be traced through the colour distribution of their globular cluster systems. The analysis, based on a galaxy sample from the Virgo ACS data, is an extension of a previous approach that has been successful in the cases of the giant ellipticals NGC 1399 and NGC 4486, and assumes that the two dominant GC populations form along diffuse stellar populations sharing the cluster chemical abundances and spatial distributions. The results show that a) Integrated galaxy colours can be matched to within the photometric uncertainties and are consistent with a narrow range of ages; b) The inferred mass to luminosity ratios and stellar masses are within the range of values available in the literature; c) Most globular cluster systems occupy a thick plane in the volume space defined by the cluster formation efficiency, total stellar mass and projected surface mass density. The formation efficiency parameter of the red clusters shows a dependency with projected stellar mass density that is absent for the blue globulars. In turn, the brightest galaxies appear clearly detached from that plane as a possible consequence of major past mergers; d) The stellar mass-metallicity relation is relatively shallow but shows a slope change at $M_*\approx 10^{10} M_\odot$. Galaxies with smaller stellar masses show predominantly unimodal globular cluster colour distributions. This result may indicate that less massive galaxies are not able to retain chemically enriched intestellar matter.

THE DISCOVERY OF REMOTE GLOBULAR CLUSTERS IN M33

We present the discovery of four remote star clusters in M33, one of which is of an extended nature. Three of the clusters were discovered using survey data from the Isaac Newton Telescope Wide-Field Camera while one was discovered serendipitously in a deep image taken with the Hubble Space Telescope's Advanced Camera for Surveys. With projected radii of 38-113 arcmin (9.6-28.5 kpc for an assumed M33 distance of 870 kpc), these clusters lie significantly beyond all but one of the currently-confirmed clusters in M33. The clusters have magnitudes and colors consistent with their being old to intermediate-age globular clusters. Indeed, they bear a strong resemblance to the outer halo GC population of the Milky Way and M31 in terms (V-I)o colors. The three outermost clusters are projected on the far side of M33 with respect to M31, an asymmetry that could suggest tidal interactions have affected M33's globular cluster distribution at large radii.

COMPARISON OF ORGANIC AND INORGANIC INSECTICIDES FOR CONTROL OF THE GERMAN COCKROACH IN APARTMENTS, 2007

The objective of this trial was to compare the effectiveness of Advion cockroach gel bait (0.6% indoxacarb) and Borid powder (99% orthoboric acid) for control of GC in apartments. The trial was conducted in low-income apartments in Indianapolis, Indiana during October 18 – December 14. GC infested apartments were randomly divided into two groups with similar GC infestation levels. Apartments in the same buildings were placed in the same group. We did not include an untreated check because previous trials showed GC populations in apartments remained stable when left untreated during this time of year. Treatments were applied on October 20 (15 apartments) and November 8 (12 apartments). Advion gel bait was applied using a baiting gun to cockroach harborages such as under the sink, kitchen cabinet door hinges, closet door corners, behind the refrigerator, in the bathroom. Borid powder was applied using a bellow duster to cracks and crevices, the perimeter of the floor, and behind cabinets and furniture. Six sticky traps were placed in each apartment for 1 d to estimate GC population levels. Locations of the traps were: 1) in the cabinetry under the kitchen sink, 2) in the cabinetry above the kitchen sink, 3) beside the stove, 4) beside the refrigerator, 5) beside the furnace, and 6) on the floor behind the toilet seat. GC population levels were estimated immediately before treatment and at 2-wk and 1-month after treatment. Log transformed trap count reduction data were analyzed by ANOVA and the means at each sampling period were separated by LSD at P = 0.05.

Predicting Metallicities and Color Distributions for Secondary GCs Forming in Spiral Galaxy Mergers at Various Redshifts

In a 1st step I present results from our new set of evolutionary synthesis models for Simple (= single burst) Stellar Populations (SSPs) of various metallicities, and in a 2nd step I combine these results with the information we have about the redshift evolution of spiral galaxies’ ISM abundances. The aim is to provide a grid of color and luminosity distributions of any secondary GC population formed at some time in the past in those mergers for comparison with observations.

Multimodal Color Distributions in the Globular Cluster Systems of Giant Elliptical Galaxies

We report on new observations of the globular cluster systems (GCSs) of two galaxies: M86 (NGC 4406) in Virgo and NGC 4696, the central giant elliptical (gE) in the Centaurus cluster. Previous observations in M86 showed no evidence for bimodality, but using only (V - I) for small cluster samples. The NGC 4696 GCS is unstudied. We used the integrated Washington (C - T1) color. This metallicity index is more than twice as sensitive to [Fe/H] as (V - I). In M86 we have about 1100 good GC candidates, and about 650 in NGC 4696, with mean internal metallicity errors ~ 0.15 dex. Both of these GCSs are found to have bimodal metallicity distributions (MDs). Our data strengthen previous results that MDs for the GCSs of gEs are widespread. The evidence for 2 separate populations in these galaxies is corroborated by examining the surface density distributions: the metal-rich clusters are more centrally concentrated than their metal-poor counterparts. The overall radial metallicity gradient present in the M86 GCS is due to the varying radial mix of the 2 populations. The existence of 2 GC populations signifies that there were 2 distinct epochs or events of cluster formation in a gE. The simple collapse model of gE formation is ruled out.

A method for subtyping group-specific component in bloodstains

A method is described for subtyping group-specific component (Gc) derived from human bloodstains. Bloodstained cuttings were extracted in 6 M urea. The extracts were subjected to ultrathin-layer polyacrylamide gel isoelectric focusing in the pH 4.5–5.4 range. After isoelectric focusing, Gc was detected by immunofixation in cellulose acetate membranes. This method permitted the successful typing of Gc in at least four-month-old bloodstains maintained at room temperature. Bloodstains from 266 liquid blood samples of known origin were subjected to both this method and immunofixation conventional agarose gel electrophoresis with no phenotypic discrepancies observed. The Gc population data for Whites from Baltimore, Maryland, were homogeneous with white sample populations from other geographical locations within the U.S.A.; whlie Gc data from northern U.S.A. black sample populations appeared to be heterogeneous compared with a southern United States black sample population.

Different populations of herpes simplex virus glycoprotein C discriminated by the carbohydrate-binding characteristics of N-acetylgalactosamine specific lectins (soybean and Helix pomatia). Brief report.

From the herpes simplex virus specified glycoprotein C two fractions were isolated with affinity either for Helix pomatia lectin (HPA) or soybean lectin (SBA). The data indicated that HPA and SBA, despite their mutual main specificity for N-acetylgalactosamine, recognize structurally different gC populations.

Populations of herpes simplex virus glycoprotein gC with and without affinity for the N-acetyl-galactosamine specific lectin of Helix pomatia.

SummaryTwo fractions of herpes simplex virus glycoprotein gC were isolated and characterized by means of immunosorbent-purification with monoclonal antibodies against gC and Helix pomatia lectin (HPA) affinity chromatography. About 25 per cent of the glycoprotein gC population demonstrated affinity for the lectin, compatible with presence of N-acetylgalactosamine as terminal sugar of the oligosaccharide. The HPA-binding populations of gC appeared as two electrophoretic bands with lower molecular weights than the non-binding gC.The gC subfraction without affinity for the HPA was subjected to treatments aiming to desialylize the carbohydrate moiety. Only 5 per cent of the initially non-reactive fraction of gC became reactive to HPA after the treatments, suggesting that masking of penultimate N-acetylgalactosamine by sialic acid was not a main reason for lack of HPA affinity. Results of treatment with alkaline Na BH4 demonstrated presence of oligosaccharide-peptide linkages sensitive to β-elimination suggesting O-glycosidic type of linkage.The subfraction of gC demonstrating affinity for HPA as well as gC devoid of HPA binding capacity both revealed affinity for Con A. Therefore N-glycosidically as well as O-glycosidically linked oligosaccharides seemed to be present on the one and same glycoprotein.On the basis of the results presented we assume that the glycosylation of HSV glycoprotein gC may lead to, at least, two populations of the glycoprotein gC, one with terminal N-acetylgalactosamine residues of oligosaccharides 0-glycosidically linked to the polypeptide and the other without affinity for HPA. However, both populations of gC contain similar proportions of oligosaccharides of the high mannose or complex types with N-glycosidic carbohydrate-peptide linkages as indicated by their affinity for Con A.