Landscape genetics of plants

Landscape genetics is the amalgamation of landscape ecology and population genetics to help with understanding microevolutionary processes such as gene flow and adaptation. In this review, we examine why landscape genetics of plants lags behind that of animals, both in number of studies and consideration of landscape elements. The classical landscape distance/resistance approach to study gene flow is challenging in plants, whereas boundary detection and the assessment of contemporary gene flow are more feasible. By contrast, the new field of landscape genetics of adaptive genetic variation, establishing the relationship between adaptive genomic regions and environmental factors in natural populations, is prominent in plant studies. Landscape genetics is ideally suited to study processes such as migration and adaptation under global change.     

A zoonotic ringworm outbreak caused by a dysgonic strain of Microsporum canis from stray cats

BackgroundCats are frequent carriers of Microsporum canis and veterinary students are at high risk of exposure and acquisition of the organism a la infección.ObjectivesAn outbreak of zoonotic ringworm carried by a litter of stray cats is described. Four veterinary students, four dogs, and six cats living in five separate locations were affected. All had direct or indirect contact with the infected kitten litter. We tried to identify the causal dermatophyte.MethodsConventional and mycological culture methods were used.ResultsMicroscopic features of scrapings and hairs treated with 20% KOH strongly suggested a M. canis etiology, and a diagnosis of ringworm was empirically supported by successful treatment of humans and animals. Nevertheless, cultures failed to show the expected morphology.ConclusionsCulture features of our strain are compared with those described by other authors for dysgonic M. canis strains. Epidemiological features are also discussed.     

Current humanized mouse models for studying human immunology and HIV-1 immuno-pathogenesis

A robust animal model for “hypothesis-testing/mechanistic” research in human immunology and immuno-pathology should meet the following criteria. First, it has well-studied hemato-lymphoid organs and target cells similar to those of humans. Second, the human pathogens establish infection and lead to relevant diseases. Third, it is genetically inbred and can be manipulated via genetic, immunological and pharmacological means. Many human-tropic pathogens such as HIV-1 fail to infect murine cells due to the blocks at multiple steps of their life cycle. The mouse with a reconstituted human immune system and other human target organs is a good candidate. A number of human-mouse chimeric models with human immune cells have been developed in the past 20 years, but most with only limited success due to the selective engraftment of xeno-reactive human T cells in hu-PBL-SCID mice or the lack of significant human immune responses in the SCID-hu Thy/Liv mouse. This review summarizes the current understanding of HIV-1 immuno-pathogenesis in human patients and in SIV-infected primate models. It also reviews the recent progress in the development of humanized mouse models with a functional human immune system, especially the recent progress in the immunodeficient mice that carry a defective gammaC gene. NOD/SCID/gammaC^−/− (NOG or NSG) or the Rag2^−/−gammaC^−/− double knockout (DKO) mice, which lack NK as well as T and B cells (NTB-null mice), have been used to reconstitute a functional human immune system in central and peripheral lymphoid organs with human CD34⁺ HSC. These NTB-hu HSC humanized models have been used to investigate HIV-1 infection, immuno-pathogenesis and therapeutic interventions. Such models, with further improvements, will contribute to study human immunology, human-tropic pathogens as well as human stem cell biology in the tissue development and function in vivo.     

Chloroquine treatment increases detection of 5-fluorouracil-induced apoptosis index in vivo

Although apoptosis can be readily assessed in vitro with a variety of techniques, the detection of apoptosis in the in vivo setting poses a much more difficult proposition. Apoptosis in an organism is followed almost inevitably by rapid clearance of dying cells via phagocytosis, thus limiting the ability to analyze apoptosis in vivo using classical techniques. To address this issue, we developed a method to enhance in vivo apoptosis detection using pretreatment with chloroquine, an inhibitor of macrophage activity, in Swiss albino mice. This technique resulted in a significant increase in the accumulation of apoptotic cells induced by 5-fluorouracil, as detected by propidium iodide staining in solid and ascitic forms of Ehrlich ascitic tumors and in bone marrow cells. We further validated our technique using DNA fragmentation and endonuclease assays. Our results demonstrated that chloroquine pretreatment can significantly enhance accumulation of apoptotic cells in organisms, and we envision combining this method with modern imaging techniques to optimize in vivo detection of apoptosis.     

Prevalence of periconceptional folic acid use and perceived barriers to the postgestation continuance of supplemental folic acid: survey results from a Teratogen Information Service

BACKGROUND: Fewer than 40% of U.S. women are taking folic acid supplements periconceptionally at a time when the risk of neural tube defects (NTDs) can be reduced by supplementation. A better understanding of the vitamin-taking habits of childbearing-age women and effective methods for improving periconceptional supplement use are needed. METHODS: A telephone survey conducted through the California Teratogen Information Service (TIS) between August 2003 and January 2004 assessed the prevalence and characteristics of pregnant callers who did not use folic acid supplements in the periconceptional period, and explored attitudes toward advice to continue vitamin use following pregnancy in order to be protected in a future pregnancy. RESULTS: A total of 327 pregnant women who called the TIS for information agreed to participate in the survey. More than half (53.2%) were not taking folic acid-containing supplements in the periconceptional period. Predictors of lack of use included a higher prepregnancy body mass index, younger maternal age, non-white race/ethnicity, lower education level, and unplanned pregnancy. One-quarter of the women said they would be willing to continue taking vitamins after the pregnancy if advised to do so by a physician. The remainder identified obstacles to following that advice--notably, not planning to become pregnant again and the belief that enough folate is derived from diet alone. CONCLUSIONS: More than half of the callers to the TIS were not compliant with recommendations regarding periconceptional folic acid supplementation. This represents an opportunity for TIS specialists and physicians to intervene in a current pregnancy to encourage maintenance of supplement use in the subsequent interpregnancy interval.     

Clinical study comparing probiotic Lactobacillus GR-1 and RC-14 with metronidazole vaginal gel to treat symptomatic bacterial vaginosis

Bacterial vaginosis (BV) is particularly common in black women, and in Nigeria it is often caused by Mycoplasma, as well as Atopobium, Prevotella and Gardnerella sp. Antimicrobial metronidazole oral therapy is poorly effective in eradicating the condition and restoring the Lactobacillus microbiota in the vagina. In this study, 40 women diagnosed with BV by discharge, fishy odor, sialidase positive test and Nugent Gram stain scoring, were randomized to receive either two dried capsules containing Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 each night for 5 days, or 0.75% metronidazole gel, applied vaginally twice a day (in the morning and evening). Follow-up at day 6, 15 and 30 showed cure of BV in significantly more probiotic treated subjects (16, 17 and 18/20, respectively) compared to metronidazole treatment (9, 9 and 11/20: P=0.016 at day 6, P=0.002 at day 15 and P=0.056 at day 30). This is the first report of an effective (90%) cure of BV using probiotic lactobacilli. Given the correlation between BV and HIV, and the high risk of the latter in Nigeria, intravaginal use of lactobacilli could provide women with a self-use therapy, similar to over-the-counter anti-yeast medication, for treatment of urogenital infections.