Direct Comparisons of 2D and 3D Dental Microwear Proxies in Extant Herbivorous and Carnivorous Mammals

The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately.     

Use of the granulosa cell aromatase bioassay for measurement of bioactive follicle-stimulating hormone in urine and serum samples of diverse species

Ovarian steroids and growth factors are intragonadal modulators which augment a key endpoint of follicle-stimulating hormone (FSH) action in granulosa cells: the induction of aromatase activity. Studies of these paracrine hormones that enhance FSH-stimulated estrogen biosynthesis by cultured rat granulosa cells, have led to the development of a sensitive and specific bioassay for FSH. This newly developed granulosa cell aromatase bioassay (GAB) allows for the measurement of bioactive FSH levels in serum and urine of humans and animals with various physiological and pathological conditions. These studies have demonstrated that the GAB assay is useful in detecting possible changes in the molecular forms of FSH. The adaptation of this method for urine samples allows for the measurement of bio-FSH levels in situations where venipuncture is not practical or in species for which specific radioimmunoassays are not available.     

C-band polymorphisms of chromosome 9: quantification by Ce-bands

Summary C-band polymorphisms of chromosome 1 can be quantified by C_e bands visualized using oblique epi-illumination. In this paper the polymorphic region of chromosome 9, including variants such as 9qh+, inversions, and translocations, was analyzed in a total of 1860 chromosomes from 20 individuals and 8 fetuses. In this sample we found between zero and five C_e bands on 9q and between zero and four C_e bands on 9p with a maximum of five C_e bands per chromosome. On the basis of these observations at least 19 different polymorphic patterns can be expected theoretically, 15 of which were observed in our sample. Among these, five polymorphic C_e-band classes were distinguishable by the method presented. Considering both homologues, 5²=25 quantitatively discernible chromosome 9 pairs may exist.     

Social context and reaction to separation in peer-reared pigtail macaques: Some preliminary observations

The social environment affects both behavioral and physiological responses to separation from the mother. Less information is available on the impact of the social environment on the response to separation in peer-reared infant monkeys. This study reports the responses of peer-reared pigtail macaque infants to repeated separations, and the impact of social versus isolation housing during the separation. The responses of two pairs of monkeys were studied during four three-day separations. One of each pair was housed in isolation during the separation, and the other was with another pair of peers, with whom they had been living for one month prior to the separation. The isolation-housed peer responded to the separation with behavioral agitation, but no depression. The socially-housed peer's behavior did not differ from baseline during the separation. During successive reunions, all the separated monkeys, regardless of housing condition, exhibited declining levels of behaviors related to maintaining proximity to their attachment figure. Although the number of subjects is small, the results suggest that the presence of social support, in the form of a familiar peer, can ameliorate the response to separation, and that with repeated separations the responses of the monkeys changes significantly.     

Interconversion of active and inactive 30 S ribosomal subunits is accompanied by a conformational change in the decoding region of 16 S rRNA

Zamir, Elson and their co-workers have shown that 30 S ribosomal subunits are reversibly inactivated by depletion of monovalent or divalent cations. We have re-investigated the conformation of 16 S rRNA in the active and inactive forms of the 30 S subunit, using a strategy that is designed to eliminate reversible ion-dependent conformational effects that are unrelated to the heat-dependent Zamir-Elson transition. A combination of structure-specific chemical probes enables us to monitor the accessibility of pyrimidines at N-3 and purines at N-1 and N-7. Chemically modified bases are identified by end-labeling followed by analine-induced strand scission (in some cases preceded by hybrid selection), or by primer extension using synthetic DNA oligomers. These studies show the following: The transition from the active to the inactive state cannot be described as a simple loosening or unfolding of native structure, such as that which is observed under conditions of more severe ion depletion. Instead, it has the appearance of a reciprocal interconversion between two differently structured states; some bases become more reactive toward the probes, whilst others become less reactive as a result of inactivation. Changes in reactivity are almost exclusively confined to the "decoding site" centered at positions 1400 and 1500, but significant differences are also detected at U723 and G791 in the central domain. This may reflect possible structural and functional interactions between the central and 3' regions of 16 S rRNA. The inactive form also shows significantly decreased reactivity at positions 1533 to 1538 (the Shine-Dalgarno region), in agreement with earlier findings. The principal changes in reactivity involve the universally conserved nucleotides G926, C1395, A1398 and G1401. The three purines show reciprocal behavior at their N-1 versus N-7 positions. G926 loses its reactivity at N-1, but becomes highly reactive at N-7 as a result of the transition of the inactive state. In contrast, A1398 and G1401 become reactive at N-1, but lose their hyper-reactivity at N-7. The possible structural and functional implications of these findings are discussed.     

The effect of pH and lysosomal extract on rat liver metallothionein (Cd-thionein)

Was studied in vitro. The¹⁰⁹Cd-labeled protein was isolated by gel filtration and incubated with a lysosomal extract from the same source. No degradation was seen when the pH of the incubation medium was 5 or higher, whereas the degradation of Cd-thionein was completed in 2 h at a pH of 4.5. Dissociation of Cd²⁺ from thionein, which takes place to a fair extent at a pH below 5, appears necessary before the enzymatic breakdown of the thionein moiety can take place.     

The effect of in vitro pretreatments on subsequent shoot organogenesis from excised Rubus and Malus leaves

Shoot regeneration from Rubus leaves was obtained on a medium containing MS salts, vitamins and sugars, Staba vitamins, casein hydrolysate (100 mg l^–1) and 10 M thidiazuron. Shoot regeneration from Malus leaves was obtained on N⁶ rice anther medium with 5 M thidiazuron. In vitro pretreatment of source shoots with either colchicine or thidiazuron enhanced the organogenic potential of detached leaves of two Rubus hybrids. The response to colchicine was quadratic and occurred at non-mutagenic concentrations (75–250 M). The response to thidiazuron was exponential between 0 and 5 M. When applied as a pretreatment, the effectiveness of several different cytokinins (benzyladenine, thidiazuron, zeatin) at enhancing Malus and Rubus organogenesis was related to the shoot proliferation activity of the cytokinin and to treatment-induced variation in leaf and petiole size.Abbreviations BA benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - IBA indolebutyric acid - MS Murashige & Skoog basal medium devoid of plant growth regulators - OI organogenesis-initiating subculture - PTI colchicine pretreatment subculture - PTII cytokinin pretreatment subculture - NAA naphthaleneacetic acid - TDZ thidiazuron - zeatin trans-zeatin     

The direction of mothers' and daughters' preferences and the heritability of male ornaments in red jungle fowl (Gallus gallus)

We used a breeding design involving 18 sires and 108 dams tostudy the heritabilities of male ornaments in red jungle fowl(Gallus gallus). Ornaments used by females to choose mates showedlow heritabilities, with the exception of comb and wattle measures.The general absence of heritability suggests that a geneticcovariance did not exist at the time of this study between mostmale ornaments and female preferences for those ornaments. Thisresult is contrary to a key prediction of the arbitrary or Fisherianhypothesis of sexual selection. Comb size and color are condition-dependenttraits that reflect short-term changes in health, and comb sizeof males was positively correlated with offspring weight. Ourresults are consistent with the expectation of good-genes hypothesesthat male ornaments reflect the ability of males to withstandenvironmental stresses.