Locations of mouse DNA damage response and repair loci, and cancer risk modifiers

An outline is presented of an electronically accessible database that compares the locations of mouse genes involved in DNA repair, apoptosis, cell cycle and signal transduction with those of known cancer risk modifier genes. The database has a primary but not exclusive focus on modifiers of ionizing radiation (IR) cancer risk and genes involved in IR-induced DNA damage responses. The database () provides a useful tool for assessing the role of DNA damage response genes in cancer predisposition.     

Localization of proteins L4, L5, L20 and L25 on the ribosomal surface by immuno-electron microscopy

Summary Ribosomal proteins L4, L5, L20 and L25 have been localized on the surface of the 50S ribosomal subunit of Escherichia coli by immuno-electron microscopy. The two 5S RNA binding proteins L5 and L25 were both located at the central protuberance extending towards its base, at the interface side of the 50S particle. L5 was localized on the side of the central protuberance that faces the L1 protuberance, whereas L25 was localized on the side that faces the L7/L12 stalk. Proteins L4 and L20 were both located at the back of the 50S subunit; L4 was located in the vicinity of proteins L23 and L29, and protein L20 was localized between proteins L17 and L10 and is thus located below the origin of the L7/L12 stalk.     

Three-dimensional in vitro follicle growth: overview of culture models,biomaterials, design parameters and future directions

In vitro ovarian follicle culture is a new frontier in assisted reproductive technology with tremendous potential, especially for fertility preservation. Folliculogenesis within the ovary is a complex process requiring interaction between somatic cell components and the oocyte. Conventional two-dimensional culture on tissue culture substrata impedes spherical growth and preservation of the spatial arrangements between oocyte and surrounding granulosa cells. Granulosa cell attachment and migration can leave the oocyte naked and unable to complete the maturation process. Recognition of the importance of spatial arrangements between cells has spurred research in to three-dimensional culture system. Such systems may be vital when dealing with human primordial follicles that may require as long as three months in culture. In the present work we review pertinent aspects of in vitro follicle maturation, with an emphasis on tissue-engineering solutions for maintaining the follicular unit during the culture interval. We focus primarily on presenting the various 3-dimensional culture systems that have been applied for in vitro maturation of follicle:oocyte complexes. We also try to present an overview of outcomes with various biomaterials and animal models and also the limitations of the existing systems.     

Food, vigilance, and sperm: the role of male direct benefits in the evolution of female preference in a polygamous bird

The adaptive significance of female selection of copulationpartners remains unresolved, particularly in polygamous specieswhere males do not provide paternal care. In these species thepossibility that direct benefits other than paternal care mayplay an important role in the evolution of female choice hasreceived little attention. I tested whether direct benefitsare associated with female choice in the polygamous feral fowl,Gallus g. domesticus, where females prefer socially dominantcopulation partners and males do not care for the young butdo provide females with three commodities: food, vigilance,and sperm. I used a combination of empirical and experimentaldata to show that male propensity to offer food and vigilance,but not sperm, was positively associated with male social status,suggesting that the provision of these resources may be costlyand condition dependent in males. Copulation success was correlatedwith male status but not with the number of feedings a femalereceived from a male, indicating that a female preferred dominantpartners that in general provided any female with more food,rather than partners that provided only her with more food,consistent with the idea that females may use male resourceprovisioning as a proximate mechanism to assess male condition.Together, these results indicate that male resources provisioningis (1) tightly linked to male social status, (2) a potentialindicator of male condition and possibly genetic quality, and(3) a potential criterion for females to select dominant partners,thus playing an important role in the evolution of partner choiceeven in polygamous species lacking paternal care.     

Influence of Food Resources on the Ranging Pattern of Northern Pig-tailed Macaques (Macaca leonina)

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability influences the ranging patterns of a group of northern pig-tailed macaques (Macaca leonina) living around the visitor center of Khao Yai National Park, Thailand. We predicted that macaques would increase their range during low fruit abundance periods to gather high-quality food and that they would go where there are more fruits or more fruits of particular species. We also predicted that human food, linked to human presence, would attract the macaques. We followed the macaques and recorded their diet and movements within their home range. We superimposed a grid on kernels defining the monthly home range surface to compare spatially macaques’ travel and the availability of fruits measured on botanical transects. Our results showed that the macaques increased their monthly home range in March, probably to obtain newly available fruits. During high fruit abundance seasons, they spent more time near particular fruit species. In August and September, although fruits became rare again, macaques kept their home range large, perhaps to find enough fruits as supplies dwindled. Finally, from October to February, they decreased their monthly home range size while consuming human food, a high-quality item. In conclusion, the macaques used several ranging strategies according to fruit availability. However, we think that, without human food, macaques would tend to increase their range during low fruit abundance periods, as predicted.     

Fungal Community Shifts in Structure and Function across a Boreal Forest Fire Chronosequence

Forest fires are a common natural disturbance in forested ecosystems and have a large impact on the microbial communities in forest soils. The response of soil fungal communities to forest fire is poorly documented. Here, we investigated fungal community structure and function across a 152-year boreal forest fire chronosequence using high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region and a functional gene array (GeoChip). Our results demonstrate that the boreal forest soil fungal community was most diverse soon after a fire disturbance and declined over time. The differences in the fungal communities were explained by changes in the abundance of basidiomycetes and ascomycetes. Ectomycorrhizal (ECM) fungi contributed to the increase in basidiomycete abundance over time, with the operational taxonomic units (OTUs) representing the genera Cortinarius and Piloderma dominating in abundance. Hierarchical cluster analysis by using gene signal intensity revealed that the sites with different fire histories formed separate clusters, suggesting differences in the potential to maintain essential biogeochemical soil processes. The site with the greatest biological diversity had also the most diverse genes. The genes involved in organic matter degradation in the mature forest, in which ECM fungi were the most abundant, were as common in the youngest site, in which saprotrophic fungi had a relatively higher abundance. This study provides insight into the impact of fire disturbance on soil fungal community dynamics.     

Cloning and nucleotide sequences of two lipase genes from Candida cylindracea.

Two lipase-encoding genes (LIP1 and LIP2) have been isolated from a SacI genomic library of the yeast Candida cylindracea and their nucleotide sequences have been determined. Comparison with the sequence of a cDNA ruled out the presence of introns in the two genes. Both ORFs encode for mature proteins of 534 residues with putative signal peptides of 15 and 14 amino acids, respectively. When compared with other lipase sequences, the two C. cylindracea lipases showed homology only with the Geotrichum candidum lipase, whereas they shared a significant similarity with several esterases.     

Electromagnetic fields produced by GSM cellular phones and heart rate variability

In this study, 26 healthy young volunteers were submitted to 900 MHz (2 W) GSM cellular phone exposure and to sham exposure in separate sessions. The study was designed to assess cardiac regulatory mechanism in different autonomic nervous system (ANS) states during exposure to low-intensity EMF. Rest-to-stand protocol was applied to evaluate ANS in quiet condition (rest, vagal prevalence) and after a sympathetic activation (stand). The procedure is conducted twice in a double-blind design: once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). During each session three-leads electrocardiograms were recorded and RR series extracted off-line. Time domain and frequency domain HRV parameters were calculated in every phase of the protocol and during different exposures. The analysis of the data show there was no statistically significant effect due to EMF exposure both on main (i.e., RR mean) and most of the other HRV parameters. A weak interaction between some HRV parameters (i.e., SDNN, TINN, and triangular index in time domain and LF power in frequency domain analysis) and RF exposure was observed and this effect seems to be gathered around the sympathetic response to stand.