Adoption of shelter dogs in a Brazilian community: assessing the caretaker profile

A survey in Ibiuna, Sao Paulo, Brazil, of caregivers (owners) who adopted shelter dogs assessed length of ownership, proportion of male and female dogs adopted, and owners' characteristics. It addressed breeding, neutering, vaccination, and veterinary care. It used no testing to provide a good “match ”between dog and future owner. Of adopted dogs, 58% were male. Only 36% of owners were located. Mean ownership length was 14.8 months (95% confidence interval = 12.4 to 17.2 months), estimated through a survival analysis method. Of adopted dogs, 40.9% lived with their owners; 34.9% had died (some had lived on the streets); 15.0% were donated; 4.3% ran away; 3.2% were returned to the city shelter. Of interviewees, 57% reported no difficulties with the adoption; 23.1% cited the animal's illness and death as the main difficulty. For contraception, 87 owners (46.7%) chained dogs to prevent contact with other animals; 56.5% were against neutering. Reasons given were compassion (58.1%), unnecessary procedure (11.4%), cost (9.5%), and behavior change (4.8%). This research motivated a design for Ibiuna shelter dog adoption to improve the proportion of successful adoptions.     

Stable carbon isotope ratios for the gray whale (<Emphasis Type="Italic">Eschrichtius robustus</Emphasis>) in the breeding grounds of Baja California Sur,Mexico

This work investigated the feeding ecology and behaviour of gray whales in Bahía Magdalena. Underwater observations of bottom feeding were made (n=4). Skin biopsies of the gray whale had a carbon isotope value of –16.5 ± 0.1 (range from –16.4 to –16.7, n=7). Prey in Bahía Magdalena had a carbon isotope value of –18.4. Dietary enrichment from prey in Bahía Magdalena would correspond to 2 ± 0.1, whereas previously published results for prey in Alaska would result in an enrichment of 3, which suggests that whales were more likely feeding on prey from Bahía Magdalena. Carbon isotopic oscillation along the baleen plate of a stranded 1-year-old whale showed a variation in diet during the year, which suggests continual feeding during this time and corresponding to dietary sample measurements from Bahía Magdalena in winter and Alaska in summer.     

Genomic DNA macroarrays as a tool for analysis of gene expression in Leishmania

Gene-array technologies have been applied in a wide number of organisms to study gene expression profiling under several physiological and experimental conditions. Gene-array implementations combined with the information arising from emerging genome sequencing projects are expected to be in the near future a major tool to characterize genes involved in different processes. So far, gene expression profile studies in trypanosomatids have been performed in microarrays that use a glass support to immobilize fragments of genomic DNA followed by fluorescent detection. Here, we wanted to test the potential of genomic DNA macroarrays of Leishmania infantum using nylon membranes and radioactive detection. Nylon macroarrays present a number of advantages since the processing of the membranes is based on standard Southern blotting protocols familiar to molecular biologists, and the data acquisition equipment is available to most research institutions. Nylon macroarrays were employed to search for genes showing increased mRNA abundance during an axenic differentiation of L. infantum promastigotes to amastigotes. Several clones were rescued and, after validation by Northern blot assays, these L. infantum sequences were used to screen the Leishmania major gene database. The L. major contigs with high homology to the L. infantum sequences allowed a consistent identification of the regulated genes.     

Passage of murine scrapie prion protein across the mouse vascular blood-brain barrier

Prions are the infectious agents associated with transmissible spongiform encephalopathies and are composed mainly of a misfolded form of the endogenous prion protein. Prion protein must enter the brain to produce disease. Previous work has emphasized various mechanisms which partially bypass the blood-brain barrier (BBB). Here, we used the brain perfusion method to directly assess the ability of mouse scrapie protein (PrP(SC)) to cross the mouse BBB independent of the influences of neural pathways or circulating immune cells. We found that PrP(SC) oligomers rapidly crossed the BBB without disrupting it with a unidirectional influx rate of about 4.4microl/g-min. HPLC and capillary depletion confirmed that PrP(SC) crossed the entire width of the capillary wall to enter brain parenchyma. PrP(SC) also entered the cerebrospinal fluid (CSF) compartment. These results show that a prion protein can cross the intact BBB to enter both the parenchymal and CSF compartments of the brain.     

Light-induced rhythmic changes in thermotolerance in stationary-phase cells of Candida utilis.

In synchronized light-dark cycles, stationary-phase cultures of the budding yeast Candida utilis were able to survive heat treatment at 50 degees C with an apparent circadian-like rhythm related to the onset of light. However, in continuous darkness this pattern did not run freely and was markedly dampened. We discuss these findings in terms of the potential circadian control of heat tolerance, which has been described in the fission yeast Schizosaccharomyces pombe. Our results suggest that the resistance pattern observed in C. utilis is most likely an adaptive response to the light-induced generation of reactive oxygen species rather than the occurrence of a truly endogenous circadian rhythm.     

Neutral-red reaction is related to virulence and cell wall methyl-branched lipids in Mycobacterium tuberculosis

Searching for virulence marking tests for Mycobacterium tuberculosis, Dubos and Middlebrook reported in 1948 that in an alkaline aqueous solution of neutral-red, the cells of the virulent H37Rv M. tuberculosis strain fixed the dye and became red in color, whereas the cells of the avirulent H37Ra M. tuberculosis strain remained unstained. In the 1950 and 1960s, fresh isolates of M. tuberculosis were tested for this neutral-red cytochemical reaction and it was reported that they were neutral-red positive, whereas other mycobacteria of diverse environmental origins that were non-pathogenic for guinea pigs were neutral-red negative. However, neutral-red has not really been proven to be a virulence marker. To test if virulence is in fact correlated to neutral-red, we studied a clinical isolate of M. tuberculosis that was originally neutral-red positive but, after more than 1 year passing through culture mediums, turned neutral-red negative. We found that, in comparison to the original neutral-red positive strain, this neutral-red negative variant was attenuated in two murine models of experimental tuberculosis. Lipid analysis showed that this neutral-red negative natural mutant lost the capacity to synthesize pthiocerol dimycocerosates, a cell wall methyl-branched lipid that has been related to virulence in M. tuberculosis. We also studied the neutral-red of different gene-targeted M. tuberculosis mutants unable to produce pthiocerol dimycocerosates or other cell wall methyl-branched lipids such as sulfolipids, and polyacyltrehaloses. We found a negative neutral-red reaction in mutants that were deficient in more than one type of methyl-branched lipids. We conclude that neutral-red is indeed a marker of virulence and it indicates important perturbations in the external surface of M. tuberculosis cells.     

ATM-Chk2-p53 activation prevents tumorigenesis at an expense of organ homeostasis upon Brca1 deficiency

BRCA1 is a checkpoint and DNA damage repair gene that secures genome integrity. We have previously shown that mice lacking full-length Brca1 (Brca1(delta11/delta11)) die during embryonic development. Haploid loss of p53 completely rescues embryonic lethality, and adult Brca1(delta11/delta11)p53+/- mice display cancer susceptibility and premature aging. Here, we show that reduced expression and/or the absence of Chk2 allow Brca1(delta11/delta11) mice to escape from embryonic lethality. Compared to Brca1(delta11/delta11)p53+/- mice, lifespan of Brca1(delta11/delta11)Chk2-/- mice was remarkably extended. Analysis of Brca1(delta11/delta11)Chk2-/- mice revealed that p53-dependent apoptosis and growth defect caused by Brca1 deficiency are significantly attenuated in rapidly proliferating organs. However, in later life, Brca1(delta11/delta11)Chk2-/- female mice developed multiple tumors. Furthermore, haploid loss of ATM also rescued Brca1 deficiency-associated embryonic lethality and premature aging. Thus, in response to Brca1 deficiency, the activation of the ATM-Chk2-p53 signaling pathway contributes to the suppression of neoplastic transformation, while leading to compromised organismal homeostasis. Our data highlight how accurate maintenance of genomic integrity is critical for the suppression of both aging and malignancy, and provide a further link between aging and cancer.     

Effects of endogenous salicylic acid on nodulation in the model legumes Lotus japonicus and Medicago truncatula

The exogenous addition of salicylic acid (SA) was previously shown to inhibit indeterminate but not determinate-type nodulation. We sought to extend these results by modulating endogenous levels of SA through the transgenic expression of salicylate hydroxylase (NahG) in both stably transformed Lotus japonicus and composite Medicago truncatula plants. NahG expression in L. japonicus resulted in a marked reduction of SA levels. This reduction correlated with an increase in the number of infections and mean nodule number when compared to controls. However, a complicating factor was that NahG-expressing plants had greater root growth. Spot inoculations of NahG-expressing L. japonicus plants confirmed increased nodulation in these plants. Consistent with the reported inhibitory effects of exogenous SA on indeterminate-type nodulation, NahG expression in M. truncatula plants led to enhanced nodulation and infection. These data point to an important role for SA-mediated plant defense pathways in controlling nodule formation on both determinate and indeterminate nodule-forming hosts.