Correction to: Stress impact of liposomes loaded with ciprofloxacin on the expression level of MepA and NorB efflux pumps of methicillin‑resistant Staphylococcus aureus

International Microbiology -     

Development of a bio-MEMS device for electrical and mechanical conditioning and characterization of cell sheets for myocardial repair

Here we propose a bio-MEMS device designed to evaluate contractile force and conduction velocity of cell sheets in response to mechanical and electrical stimulation of the cell source as it grows to form a cellular sheet. Moreover, the design allows for the incorporation of patient-specific data and cell sources. An optimized device would allow cell sheets to be cultured, characterized, and conditioned to be compatible with a specific patient's cardiac environment in vitro, before implantation. This design draws upon existing methods in the literature but makes an important advance by combining the mechanical and electrical stimulation into a single system for optimized cell sheet growth. The device has been designed to achieve cellular alignment, electrical stimulation, mechanical stimulation, conduction velocity readout, contraction force readout, and eventually cell sheet release. The platform is a set of comb electrical contacts consisting of three-dimensional walls made of polydimethylsiloxane and coated with electrically conductive metals on the tops of the walls. Not only do the walls serve as a method for stimulating cells that are attached to the top, but their geometry is tailored such that they are flexible enough to be bent by the cells and used to measure force. The platform can be stretched via a linear actuator setup, allowing for simultaneous electrical and mechanical stimulation that can be derived from patient-specific clinical data.     

Sequence analysis of the conserved protamine gene cluster shows that it contains a fourth expressed gene

Structural data are presented on the protamine gene cluster (PGC) of human, mouse, rat, and bull. By restriction mapping we demonstrate that the organization of the protamine cluster is conserved throughout all four species, i.e., the genes are situated in a head to tail arrangement in the order: protamine l-protamine 2-transition protein 2. Further, we established the nucleotide sequence of the entire human PGC (25 kb in total) and the 3′ portion of the rat protamine cluster (PRM2 and TNP2 genes and intergenic region). In addition, a 1 kb fragment of the bovine and murine protamine cluster, situated between PRM2 and TNP2, was sequenced. This fragment is conserved regarding sequence, position, and orientation in all species examined, and was classified as likely coding region by gene recognition program GRAIL. Using the rat fragment as a probe in RNA blots, we detected a testis-specific signal of about 0.5 kb. Finally, we demonstrate a high density of Alu elements, both full and fragmented copies, in the human PGC and discuss their localization with respect to evolutionary and functional aspects. © 1996 Wiley-Liss, Inc.     

Formation of lipid reserves in fat body and eggs of the yellow fever mosquito, Aedes aegypti

We examined the accumulation of lipids in adult females of the mosquito, Aedes aegypti. Females emerged with about 100 μg lipid in the fat body. With access to sugar water lipids increased over seven days to 300 μg. After a blood meal on day five, sugar-fed females accumulated 120-140 μg of lipids in their ovaries within 2 days. At the same time the lipid content of the fat body decreased by 100 μg, indicating transfer of lipids from fat body to oocytes. Experiments in which fat body lipids were prelabelled support this conclusion. Label was transferred to oocytes: in mature oocytes the specific radioactivity of lipids was 80% of the specific radioactivity of prelabeled fat body lipids. Components of blood meals are also used to synthesize oocyte lipids. Fat bodies of females starved for four days had only 27 μg of lipids left. When these females were given a blood meal, they matured oocytes, although the number of ooyctes was reduced and ovaries contained only half the amount of lipids found in ovaries of females which had first fed on sugar water. Fat body lipids of these females had only slightly increased to 36 μg. This demonstrates that female Ae. aegypti use sugar to synthesize lipids, but they can also use components of blood for this purpose.     

Biosynthesis of fat from some organic acids in submerged cultures of penicillium spinulosum

Summary The formation of fat from citric, succinic, fumaric and malic acids by Penicillium spinulosum has been investigated. Sodium arseite, -sulfonic propionic acid and mono-iodoacetate was found to control unfavourably the formation of fat from the organic acids by the preformed pellets of the organism. Moreover, iodoacetate reduced the mean molecular weight of the component fatty acids. The -sulfonic propionic acid though reduced the yields of fat yet the ratio fat/100 g of acid consumed was not markedly altered by this compound. A modified chromatographic method was described for the assay of different acids.With 3 Figures in the text     

Effects of therapeutic and toxic doses of levamisole on thyroid hormones and some biochemical parameters in sheep

This study was carried out to establish the effects of therapeutic and toxic doses of levamisole on thyroid hormone levels and some biochemical parameters in sheep. Twelve Akkaraman ewes were used. Levamisole was given orally at doses of 7.5 mg kg(-1) (group 1) and 40 mg kg(-1) (group 2) to the animals. Blood samples were taken from the jugular vein at 2, 4, 8, 24, 48, 96 and 144 h after the administrations. Serum thyroid hormones and some biochemical parameters were determined on these samples. When compared with the control levels, no significant changes were observed in triiodothyronine (T3) and thyroxin (T4) levels in group 1. Although levamisole was found to increase the levels of total T3, it decreased the levels of total T4 in group 2. On the other hand, free T3 and free T4 levels were not changed in either group. While serum alkaline phosphatase (ALP) activities were decreased, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and creatinine kinase (CK) activities were increased significantly by levamisole. However, it increased the serum albumin and cholesterol levels, but decreased the inorganic phosphate levels in groups 1 and 2. On the other hand, when compared with the control levels, no significant changes were detected in serum sodium, potassium and calcium levels. In conclusion, therapeutic and toxic doses of levamisole were determined to affect thyroid metabolism and some biochemical parameters in sheep.     

Biological activity and conformational analysis of C20 and C14 epimers of CD-ring modified trans-decalin 1alpha,25-dihydroxyvitamin D analogs

In the context of our ongoing study of vitamin D structure-function relationships and in an attempt to obtain a better dissociation of their prodifferentiating (HL-60) and/or antiproliferative (MCF-7) activities and their calcemic activity, further 20-epi and 14-epi modifications were made to three trans-decalin CD-ring analogs of 1,25-dihydroxyvitamin D(3), the hormonally active metabolite of vitamin D(3), possessing a natural 20R side chain and featuring additional structural modifications in the seco-B-ring and in the A-ring. Following a previously observed trend and in agreement with the conformational analysis results, all three 20-epi derivatives show substantially lower biological activities, opposite to what is usually observed for analogs having the natural CD-ring. The 14-epi modification (cis-decalins) has little effect on the biological activity of the ynediene type and the saturated derivative, but results in an approximate 10-fold reduction in activity of the previtamin derivative. No better dissociation of the prodifferentiating and/or antiproliferative activities and the calcemic activity was achieved.     

Emission of Plutella xylostella-induced compounds from cabbages grown at elevated CO2 and orientation behavior of the natural enemies

Several plant species defend themselves indirectly from herbivores by producing herbivore-induced volatile compounds that attract the natural enemies of herbivores. Here we tested the effects of elevated atmospheric CO(2) (720 micromol mol(-1)) concentration on this indirect defense, physiological properties, and constitutive and induced emissions of white cabbage (Brassica oleracea ssp. capitata, cvs Lennox and Rinda). We monitored the orientation behavior of the generalist predator Podisus maculiventris (Heteroptera: Pentatomidae) and the specialist parasitoid Cotesia plutellae (Hymenoptera: Braconidae) to plants damaged by Plutella xylostella (Lepidoptera: Plutellidae) in the Y-tube olfactometer. Elevated CO(2) levels did not affect stomatal densities but reduced specific leaf area and increased leaf thickness in cv Lennox. In addition to enhanced constitutive monoterpene emission, P. xylostella-damaged cabbages emitted homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene, sesquiterpene (E,E)-alpha-farnesene, and (Z)-3-hexenyl acetate. Growth at elevated CO(2) had no significant effect on the emissions expressed per leaf area, while minor reduction in the emission of homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-alpha-farnesene was observed at elevated CO(2) in one of two experiments. The generalist predator P. maculiventris discriminated only between the odors of intact and P. xylostella-damaged cv Rinda plants grown at ambient CO(2) concentration, preferring the odor of the damaged plants. The specialist parasitoid C. plutellae preferred the odor of damaged plants of both cultivars grown at ambient CO(2) but did not detect damaged cv Lennox plants grown at elevated CO(2). The results suggest that elevated atmospheric CO(2) concentration could weaken the plant response induced by insect herbivore feeding and thereby lead to a disturbance of signaling to the third trophic level.