Evaluation of the microbial growth response to inorganic nanoparticles

In order to enhance the utilization of inorganic nanoparticles in biological systems, it is important to develop a fundamental understanding of the influence they have on cellular health and function. Experiments were conducted to test silica, silica/iron oxide, and gold nanoparticles for their effects on the growth and activity of Escherichia coli (E. coli). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to characterize the morphology and quantify size distribution of the nanoparticles, respectively. TEM was also used to verify the interactions between composite iron oxide nanoparticles and E. coli. The results from DLS indicated that the inorganic nanoparticles formed small aggregates in the growth media. Growth studies measured the influence of the nanoparticles on cell proliferation at various concentrations, showing that the growth of E. coli in media containing the nanoparticles indicated no overt signs of toxicity.     

Ontogeny of gut morphology in the white shrimp Penaeus setiferus (Decapoda,Penaeidae)

Ontogeny of the gut in Penaeus setiferus was investigated by reconstruction of serial sections examined by light microscopy. Development of the gut into the adult form is protracted over several weeks beyond metamorphosis in steps that may be directly related to the unique postlarval life history of Penaeus. The gastric mill is lacking in larval stages of P. setiferus. In protozoeal stages Z₁-Z₃, the pyloric ampullae are blind sacs that do not communicate with the midgut. The gland filter first appears in mysis stage M₂. The gastric mill in early postlarval (PL) stages consists of poorly chitinized lobes with flexible setae. By PL₂₁ the ossicles of the gastric mill are rigid and setae are replaced by spine-like denticles, but even by PL₃₅ the gastric mill is neither as massive nor heavily chitinized as in adults. During the mysis stages and early PL stages, the hepatopancreas communicates freely with both the foregut and the midgut trunk. By PL₃₅ the hepatopancreatic ducts are essentially isolated from the remainder of the midgut by foregut ossicles. The midgut in Z₁ consists of two pairs of simple caeca and the midgut trunk. During larval growth, each of the lateral midgut caeca develops into a number of lobes. After metamorphosis these lobes begin to ramify into small-diameter tubules, and by PL₃₅ have completely ramified into the hepatopancreas of adults. From M₁ to PL₄, the anterior midgut caeca decrease in absolute size and become a single anterior diverticulum. The posterior midgut diverticulum first appears in PL₂₁ as a simple sac and thereafter increases in size and complexity.     

Isolation and characterization of a novel human prostatic stromal cell culture: DuK50

Summary A novel human prostatic stromal cell culture, designated DuK50, has been passedin vitro >12 mo. Tissue cultures were obtained from material harvested within a normal region of a radical prostatectomy specimen. These monolayers exhibited normal fibroblastic characteristics with each cell having a flattened, elongated appearance. Karyotypic analysis revealed a normal, male 46, XY chromosomal content with no numerical or structural abnormalities. DNA analysis using a Cell Analysis Systems Image Analyzer confirmed a euploid DNA content (7.9 pg DNA). Cellular markers for verification of stromal cell type were performed by immunohistochemical techniques. DuK50 stained positive for vimentin and fibronectin. Immunostains for epithelial cytokeratins and prostate-specific antigen were negative, which ruled out contamination with prostatic epithelial cells. Negative immunostaining with desmin monoclonal antibody and light staining with smooth muscle actin alpha is consistent with the staining pattern of myofibroblasts. Response to various androgens, measured by a microculture tetrazolium assay technique, revealed a significant growth stimulation of DuK50. Soft agar invasiveness assays and tumorigenicity studies in nude mice were negative. DuK50 exhibits a rapid doubling time with excellent plating efficiency, thrives in a readily available media supplemented with fetal bovine serum, and passes with routine trypsin protocols. The availability of this prostatic stromal cell culture may facilitate studies on this cell type’s role in growth factor modulation, drug and steroid metabolism, and stromal-epithelial interactions in the prostate. Presented at the Congress on Cell and Tissue Culture, Research Triangle Park, NC, June 1994.     

Localization of membrane-associated calcium during development of fucoid algae using chlorotetracycline

During the first day of development, fertilized eggs of fucoid algae generate an embryonic axis and commence rhizoid growth at one pole. Using Fucus distichus (L.) Powell, F. vesiculosus L. and Pelvetia fastigiata (J.Ag.) DeTony we have investigated the role of calcium in axis formation and fixation as well as in tip growth. The intracellular distribution of membrane-associated calcium was visualized with the fluorescent calcium probe chlorotetracycline (CTC). Punctate fluorescence associated with organelle-like structures was found in conjunction with diffuse staining at all developmental stages. This membrane-associated calcium remained uniformly distributed throughout the cortical cytoplasm while the axis was established, but increased in the rhizoid protuberance at germination. In subsequent development, fluorescence was restricted to the cortical cytoplasm at the elongating tip and at sites of crosswall biosynthesis.The requirement for Ca²⁺ uptake during development was investigated through inhibition studies; influx was impaired with transport antagonists or by removal of extracellular calcium. Both treatments curtailed germination and tip elongation but had little effect on axis polarization. Reductions in external calcium that interfered with elongation also markedly reduced the apical CTC fluorescencence, indicating that calcium uptake and localization are prerequisites for tip growth. This apical Ca²⁺ is probably involved in the secretory process that sustains tip elongation. By contrast, calcium was not implicated in the generation of an embryonic axis.Abbreviations ASW artificial seawater - CTC chlorotetracycline - DU developmental unit - EGTA erhylene glycol bis(amino-ethyl ether) N,N,N¹,N¹–tetraacetic acid - NPN N-phenyl-1-napthylamine     

Variation of metabolites in normal human urine

Urine is often sampled from patients participating in clinical and metabolomic studies. Biological homeostasis occurs in humans, but little is known about the variability of metabolites found in urine. It is important to define the inter- and intra-individual metabolite variance within a normal population before scientific or clinical conclusions are made regarding different pathophysiologies. This study investigates the variability of selected urine metabolites in a group of 60 healthy men and women over a period of 30 days. To monitor individual variation, 6 women from the normal population were randomly selected and followed for 30 days. To determine the influence of extraneous environmental factors urine was collected from 25 guinea pigs with similar genetics, diet, and living environment. For both studies, 24 metabolites were identified and quantified using high-resolution ¹H nuclear magnetic resonance spectroscopy (NMR). The data demonstrated large inter and intra-individual variation in metabolite concentrations in both normal human and control animal populations. A defined normal baseline is essential before any conclusions may be drawn regarding changes in urine metabolite concentrations.     

Sex-biased immunity is driven by relative differences in reproductive investment

Sex differences in immunity are often observed, with males generally having a weaker immune system than females. However, recent data in a sex-role-reversed species in which females compete to mate with males suggest that sexually competitive females have a weaker immune response. These findings support the hypothesis that sexual dimorphism in immunity has evolved in response to sex-specific fitness returns of investment in traits such as parental investment and longevity, but the scarcity of data in sex-reversed species prevents us from drawing general conclusions. Using an insect species in which males make a large but variable parental investment in their offspring, we use two indicators of immunocompetence to test the hypothesis that sex-biased immunity is determined by differences in parental investment. We found that when the value of paternal investment was experimentally increased, male immune investment became relatively greater than that of females. Thus, in this system, in which the direction of sexual competition is plastic, the direction of sex-biased immunity is also plastic and appears to track relative parental investment.     

Polarization of the endomembrane system is an early event in fucoid zygote development

Background  

Fucoid zygotes are excellent experimental organisms for investigating mechanisms that establish cell polarity and determine the site of tip growth. A common feature of polarity establishment is targeting endocytosis and exocytosis (secretion) to localized cortical domains. We have investigated the spatiotemporal development of endomembrane asymmetry in photopolarizing zygotes, and examined the underlying cellular physiology.     

High summer temperatures are associated with poorer performance of underyearling Atlantic salmon (Salmo salar) in upland streams

Future warming scenarios are predicted to result in an increased frequency of high, and potentially stressful, temperatures in aquatic ecosystems. Here we examined whether the performance of wild underyearling Atlantic salmon (Salmo salar) in Scottish streams stocked with identical egg densities was influenced by thermal stress. Biomass and density declined with degree hours exceeding 23°C, indicating apparent mortality or emigration as a possible result of exposure to high temperatures. These results strengthen the need for further action such as riparian tree planting to reduce stream summer temperatures.     

Ultrastructure of the ampullary organs of Plicofollis argyropleuron (Siluriformes: Ariidae)

The morphology of ampullary organs in Plicofollis argyropleuron, collected from a southeast Queensland estuary, was examined by light and electron microscopy to assess the morphological characteristics of teleost ampullary organs in environments with fluctuating salinities. This catfish possesses both macroampullae and microampullae. Both have the typical teleost arrangement of an ampullary pore linked by a canal to a single ampulla that is lined with receptor and supportive cells. The canal wall of macroampullae consists of a collagen sheath, a basement membrane, and two layers of squamous epithelial cells adjacent to the lumen, joined by desmosomes and tight junctions near the surface of the epithelium. Ampullary pore diameters are similar in range for both the macroampullae and the microampullae, with microampullae always arising from the larger pores within a single region of the head. Canal length of the macroampullae is longer than those of the microampullae. Macroampullae also contain approximately 10 times as many receptor cells compared with the microampullae. In both organs, these pear‐shaped receptor cells alternate with supportive cells along the entire luminal surface of the ampulla. The apical region of receptor cells extends into the lumen and bears numerous microvilli. The basal region of receptor cells adjoins to either individual or multiple unmyelinated neural terminals. The coexistence of two markedly different ampullary organ morphologies within a single species support theories concerning the possible multifunctionality of these sensory organs. J. Morphol., 276:1405–1411, 2015. © 2015 Wiley Periodicals, Inc.