The normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the aetiology of these diseases. Common wisdom is that lactobacilli dominate the normal vaginal microflora of post-pubertal women. However, this conclusion is based on methods that require cultivation of microbial populations; an approach that is known to yield a biased and incomplete assessment of microbial community structure. In this study cultivation-independent methods were used to analyse samples collected from the mid-vagina of five normal healthy Caucasian women between the ages of 28 and 44. Total microbial community DNA was isolated following resuspension of microbial cells from vaginal swabs. To identify the constituent numerically dominant populations in each community 16S rRNA gene libraries were prepared following PCR amplification using the 8f and 926r primers. From each library, the DNA sequences of approximately 200 16S rRNA clones were determined and subjected to phylogenetic analyses. The diversity and kinds of organisms that comprise the vaginal microbial community varied among women. Species of Lactobacillus appeared to dominate the communities in four of the five women. However, the community of one woman was dominated by Atopobium sp., whereas a second woman had appreciable numbers of Megasphaera sp., Atopobium sp. and Leptotrichia sp., none of which have previously been shown to be common members of the vaginal ecosystem. Of the women whose communities were dominated by lactobacilli, there were two distinct clusters, each of which consisted of a single species. One class consisted of two women with genetically divergent clones that were related to Lactobacillus crispatus, whereas the second group of two women had clones of Lactobacillus iners that were highly related to a single phylotype. These surprising results suggest that culture-independent methods can provide new insights into the diversity of bacterial species found in the human vagina, and this information could prove to be pivotal in understanding risk factors for various infectious diseases. INTRODUCTIONPrevious studies on the microbial flora of the human vagina indicate that micro-organisms normally present in the human vagina play a key role in preventing successful colonization by 'undesirable' organisms, including those responsible for bacterial vaginosis, yeast infections, sexually transmitted diseases and urinary tract infections (Donders et al., 2000;Gupta et al., 1998;Sobel, 1999;van De Wijgert et al., 2000). Moreover, epidemiologic studies have clearly established that abnormal vaginal microbial communities and lower genital tract infections are significantly associated with an increased risk of HIV infection (Cohen et al., 1995;Martin et al., 1999;Sewankambo et al., 1997). Based on this, researchers have speculated that the normal vaginal microbial ecosystem may play a pivotal role in lo...
Previous studies indicated that inorganic pyrophosphatase of
Inorganic pyrophosphatase (PPase) is an important enzyme that catalyzes the hydrolysis of inorganic pyrophosphate (PPi) into ortho‐phosphate (Pi). We report here the molecular cloning and characterization of a gene encoding the soluble PPase of the roundworm Ascaris suum. The predicted A. suum PPase consists of 360 amino acids with a molecular mass of 40.6 kDa and a pI of 7.1. Amino acid sequence alignment and phylogenetic analysis indicates that the gene encodes a functional Family I soluble PPase containing features identical to those of prokaryotic, plant and animal/fungal soluble PPases. The Escherichia coli‐expressed recombinant enzyme has a specific activity of 937 µmol Pi·min−1·mg−1 protein corresponding to a kcat value of 638 s−1 at 55 °C. Its activity was strongly dependent on Mg2+ and was inhibited by Ca2+. Native PPases were expressed in all developmental stages of A. suum. A homolog was also detected in the most closely related human and dog roundworms A. lumbricoides and Toxocara canis, respectively. The enzyme was intensely localized in the body wall, gut epithelium, ovary and uterus of adult female worms. We observed that native PPase activity together with development and molting in vitro of A. suum L3 to L4 were efficiently inhibited in a dose‐dependent manner by imidodiphosphate and sodium fluoride, which are potent inhibitor of both soluble‐ and membrane‐bound H+‐PPases. The studies provide evidence that the PPases are novel enzymes in the roundworm Ascaris, and may have crucial role in the development and molting process.
With the increasing prevalence of obesity in women of reproductive age there is a need to understand the ramifications of this on offspring. The purpose of this study is to investigate the programming effects of maternal obesity during preconception and the preconception/gestational period on adiposity and adipose tissue inflammation in offspring using an animal model. Adult female C57Bl/6J mice were assigned either normal diet, high fat diet (HFD) prior to pregnancy, or HFD prior to and through pregnancy. Some offspring were maintained on normal diet while others started HFD later in life. Offspring were assessed for body composition and metabolic responses. Lipid storing tissues were evaluated for expansion and inflammation. Male offspring from the preconception group had the greatest weight gain, most subcutaneous adipose tissue, and largest liver mass when introduced to postnatal HFD. Male offspring of the preconception/gestation group had worsened glucose tolerance and an increase in resident (CD11c−) adipose tissue macrophages (ATMs) when exposed to postnatal HFD. Female offspring had no significant difference in any parameter between the diet treatment groups. In conclusion, this study demonstrates that prenatal and pregnancy windows have independent programming effects on offspring. Preconception exposure affects body composition and adiposity while gestation exposure affects metabolism and tissue immune cell phenotypes.
The amount of pasture grown and converted to animal product is closely linked with the profitability of pasturebased systems. Kikuyu (Pennisetum clandestinum Hochst. ex Chiov.) is the predominant C 4 grass in coastal Australian beef and dairy systems. These kikuyu-based production systems face several key challenges to achieving high levels of productivity. In this review, we bring together the literature to highlight the opportunities for closing the gap between current and potential utilisation and for increasing dairy production from kikuyu-based pastures. More specifically, we highlight the significant gains that can be made on kikuyu-based commercial farms based on a conceptual model to show where the main losses originate, namely input and grazing management. The physical limitations associated with kikuyu for dairy systems are also presented, such as the relatively higher content of cell wall and lower content of water-soluble carbohydrates, together with nutrient imbalances relative to other grass species. Together, these limitations clearly indicate the need of supplying cows with supplements (particularly grain-based concentrates) to achieve moderate to high milk yield per cow. To achieve this without compromising pasture utilisation, dairy producers farming on kikuyu-based pastures need to use relatively greater stocking rates to generate enough demand of feed that can be used to align rate of pasture intake with rate of pasture growth, creating enough deficit of feed per cow to justify the addition of supplementary feed without impinging on pasture utilisation. The variability that exists between cows in kikuyu dry matter and neutral detergent fibre intake is also highlighted in this review, opening up new avenues of research that may allow significant productivity gains for kikuyu-based dairy farming in the future.
We recently cloned a protective antigen that is commonly expressed in Ascaris species that infect humans and pigs. We evaluated the vaccinal effects of this 16-kilodalton protein (As16) in pigs, the natural host of Ascaris suum, by intranasal immunization. Pigs that received Escherichia coli-expressed recombinant As16 (rAs16) coupled with cholera toxin (CT) had significantly elevated levels of rAs16-specific serum immunoglobulin G (IgG) and mucosal-associated IgA antibodies. rAs16 evoked a type II immune response characterized by elevated levels of interleukin-4 and -10 in the culture supernatants of peripheral blood mononuclear cells of the vaccinated pigs. An increased level of rAs16-specific serum IgG1 was also detected. Pigs vaccinated with rAs16-CT were protected from migration of A. suum larvae through the lungs, as indicated by a 58% reduction in the recovery of lung-stage third-stage larvae (L3), compared with that in nonvaccinated controls. Purified immunoglobulin from rAs16-CT-vaccinated pigs inhibited survival of infective L3 and interrupted the molting of lung-stage L3. Immunofluorescence studies revealed that this immunoglobulin bound to the digestive tracts of L3, suggesting that it might inactivate functions of the gut tissues of Ascaris species. We conclude that rAs16 is a promising mucosal vaccine candidate for pig and human ascariasis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.