Healthcare-associated infections (HAIs) remain a serious public health problem. In previous work, two models of an intensive care unit (ICU) showed that differing population structures had markedly ...different rates of Staphylococcus aureus (MRSA) transmission. One explanation for this difference is the models having differing long-term equilbrium dynamics, resulting from different basic reproductive numbers, R0. We find in this system however that this is not the case, and that both models had the same value for R0. Instead, short-term, transient dynamics, characterizing a series of small, self-limiting outbreaks caused by pathogen reintroduction were responsible for the differences. These results show the importance of these short-term factors for disease systems where reintroduction events are frequent, even if they are below the epidemic threshold. Further, we examine how subtle changes in how a hospital is organized-or how a model assumes a hospital is organized-in terms of the admission of new patients may impact transmission rates. This has implications for both novel pathogens introduced into ICUs, such as Ebola, MERS or COVID-19, as well as existing healthcare-associated infections such as carbapenem-resistant Enterobacteriaceae.
Elucidation of the O-specific polysaccharide chain of lipopolysaccharide (LPS) from Rickettsia typhi, the etiological agent of endemic typhus, is described. Structural information was established by ...a combination of monosaccharide and methylation analyses of the O-chain, and by mass (MS) and nuclear magnetic resonance (NMR) spectrometries of oligosaccharides arised through its hydrofluoric (HF) acid degradation. Based on the combined data from these experiments, two major polymer populations of the O-specific chain have been determined with the following structural features: α-L-QuiNAc-(1→4)-α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)n-α-D-Glc-(1→4)-α-D-Glc→, α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)-α-D-Glc-(1→3)-α-L-QuiNAc-(1→4)n-α-D-Glc→. The linear backbone is most probably flanked with short side chains of D-GlcNAc-(1→3)-α-L-QuiNAc-(1→3)-D-GlcNAc→ that are attached to it via L-QuiNAc as a branching point. It is suggested that a dimer α-L-QuiNAc-(1→3)-α-D-GlcNAc may represent a common epitope in the O-antigens of Proteus vulgaris OX19 and R. typhi responsible for the observed serological cross-reactivity.
The lysophospholipid mediators, lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), are responsible for cell signaling in diverse pathways including survival, proliferation, motility, and ...differentiation. Most of this signaling occurs through an eight-member family of G-protein coupled receptors once known as the endothelial differentiation gene (EDG) family. More recently, the EDG receptors have been divided into two subfamilies: the lysophosphatidic acid subfamily, which includes LPA1, (EDG-2/VZG-1), LPA2 (EDG-4), and LPA3 (EDG-7), and the sphingosine-1-phosphate receptor subfamily, which includes S1P1 (EDG-1), S1P2 (EDG-5/H218/AGR16), S1P3 (EDG-3), S1P4 (EDG-6), and S1P5 (EDG-8/NRG-1). The ubiquitous expression of these receptors across species, coupled with their diverse cellular functions, has made lysophospholipid receptors an important focus of signal transduction research. Neuroscientists have recently begun to explore the role of lysophospholipid receptors in a number of cell types; this research has implicated these receptors in the survival, migration, and differentiation of cells in the mammalian nervous system.
Glycerophospholipids (GP) extracted from the Coxiella burnetii strain Nine Mile in virulent phase I (NM I) and low virulent phase II (NM II) were analyzed by Fourier transform ion cyclotron resonance ...(FT-ICR) mass spectrometry (MS) that gave a superior mass resolution and mass accuracy allowing unambiguous peak recognition and precise assignment of ions. We showed that GP present in the pathogen's outer membrane underwent considerable modifications during the phase variation that might be related to impact of various environmental factors. It was found that GP from phase I cells were much more complex than those from phase II cells. While glycerophosphoethanolamines (PE), glycerophosphocholines (PC) and glycerophosphoglycerols (PG) were present in both phases of C. burnetii, major differences were observed in the presence of glycerophosphates (PA) and glycerophosphoserines (PS). Thus, PA but no PS were detected in NM I variant in contrast with NM II cells where PS but no PA were identified. It is suggested that enzymes for PA head group modifications to form PS, PE, and PG become active during the phase variation of the bacterium.
The aim of this in vitro study was to examine the secretion activity (progesterone, 17beta-estradiol and insulin-like growth factor-I) of rat ovarian fragments after molybdenum (Mo) addition. Rat ...ovarian fragments were incubated with ammonium molybdate (NH(4))(6)Mo(7)O(24).4H(2)O at the doses 90, 170, 330 and 500 microg.ml(-1) for 24 h and compared with control group without Mo addition. Release of progesterone (P(4)), estradiol (17beta-estradiol) and insulin-like growth factor I (IGF-I) by ovarian fragments was assessed by radioimmunoassay (RIA). Data show that P(4) release by ovarian fragments was not affected by (NH(4))(6).Mo(7)O(24).4H(2)O addition at all the doses used (90-500 microg.ml(-1)). However, addition of ammonium molybdate was found to cause a significant (P<0.05) dose-dependent decrease (at the doses 90, 170 and 500 microg.ml(-1)) in release of 17beta-estradiol by ovarian fragments in comparison to control. Also, addition of ammonium molybdate significantly (P<0.05) inhibited IGF-I release at all the doses (90-500 microg.ml(-1)) used in the study. Results suggest ammonium molybdate induced inhibition in the release of growth factor IGF-I and its dose-dependent effect on secretion of steroid hormone 17beta-estradiol but not progesterone. These data contribute to new insights regarding the mechanism of action of Mo on rat ovarian functions.
Summary
The aim of this study was to examine possible effects of bee pollen added to the feed mixture (FM) on rat ovarian functions (secretion activity and apoptosis). We evaluated the bee pollen ...effect on the release of insulin‐like growth factor I (IGF‐I) and steroid hormones (progesterone and estradiol), as well as on the expression of markers of apoptosis (Bcl‐2, Bax and caspase‐3) in rat ovarian fragments. Female rats (n = 15) were fed during 90 days by FM without or with rape seed bee pollen in dose either 3 kg/1000 kg FM or 5 kg/1000 kg FM. Fragments of ovaries isolated from rats of each group (totally 72 pieces) were incubated for 24 h. Hormonal secretion into the culture medium was detected by RIA. The markers of apoptosis were evaluated by Western blotting. It was observed that IGF‐I release by rat ovarian fragments was significantly (p < 0.05) decreased; on the other hand, progesterone and estradiol secretion was increased after bee pollen treatment at dose 5 kg/1000 kg FM but not at 3 kg/1000 FM. Accumulation of Bcl‐2 was increased by bee pollen added at 3 kg/1000 kg FM, but not at higher dose. Accumulation of Bax was increased in ovaries of rats fed by bee pollen at doses either 3 or 5 kg/1000 kg FM, whilst accumulation of caspase‐3 increased after feeding with bee pollen at dose 5 kg/1000 kg FM, but not at 3 kg/1000 kg FM. Our results contribute to new insights regarding the effect of bee pollen on both secretion activity (release of growth factor IGF‐I and steroid hormones progesterone and estradiol) and apoptosis (anti‐ and pro‐apoptotic markers Bcl‐2, Bax and caspase‐3). Bee pollen is shown to be a potent regulator of rat ovarian functions.
In this study, the effects of cadmium applied per os on fertility, live weight of newly hatched chicks, and cadmium concentrations in some organs of young and adult pheasants were investigated. The ...metal was applied at the concentration of 1.5
mg Cd
2+/L during 3 months. After the egg laying, the numbers of eggs laid, cracked, and unfertilized were determined and the live weights of newly hatched chicks were measured. The cadmium concentrations in liver, kidney, and muscle (
m. pectoralis) of young and adult pheasants were analyzed. We found that cadmium exposure of the adults did not affect the number of eggs laid but resulted in more eggs being damaged. Hatchlings were significantly heavier in the cadmium-treated group (21.36±2.28
g) compared to the control group (20.91±1.97
g) 4 weeks after the cadmium intake. Higher cadmium concentrations were observed in the muscle and kidney tissue of newly hatched pheasants after 4 weeks compared to the cadmium-exposed groups after 8 and 12 weeks. The cadmium concentrations in kidneys and liver increased significantly in adult pheasants. The metal had accumulated especially in kidneys of the adult pheasants and reached levels up to 9.64
mg/kg wet weight 3 months after the daily cadmium intake in drinking water. The concentration in liver of the adults was 3.53
mg/kg wet weight.
Q fever is a zoonotic disease caused by Coxiella burnetii . Easy aerosol dissemination, strong environmental persistence and high infectivity make the bacterium a serious threat for humans and ...animals. A rapid, sensitive and specific test for the infectious agent is still a challenge in the field. C. burnetii expresses a spectrum of amphophilic macromolecules on its surface. Among them, a lipopolysaccharide (LPS) is of particular biological, immunological and medical significance 1 . Upon serial laboratory passages in yolk sacs of embryonated hen eggs, C.
PDF
