Quantifying Single Microvessel Permeability in Isolated Blood-perfused Rat Lung Preparation

The isolated blood-perfused lung preparation is widely used to visualize and define signaling in single microvessels. By coupling this preparation with real time imaging, it becomes feasible to determine permeability changes in individual pulmonary microvessels. Herein we describe steps to isolate rat lungs and perfuse them with autologous blood. Then, we outline steps to infuse fluorophores or agents via a microcatheter into a small lung region. Using these procedures described, we determined permeability increases in rat lung microvessels in response to infusions of bacterial lipopolysaccharide. The data revealed that lipopolysaccharide increased fluid leak across both venular and capillary microvessel segments. Thus, this method makes it possible to compare permeability responses among vascular segments and thus, define any heterogeneity in the response. While commonly used methods to define lung permeability require postprocessing of lung tissue samples, the use of real time imaging obviates this requirement as evident from the present method. Thus, the isolated lung preparation combined with real time imaging offers several advantages over traditional methods to determine lung microvascular permeability, yet is a straightforward method to develop and implement.     

Ethylene and IAA interactions in the inhibition of photoperiodic flower induction of <Emphasis Type="Italic">Pharbitis nil</Emphasis>

It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis.     

Examination of Induced Sputum In the Diagnosis of Pneumocystis Carinii Pneumonia

The results of the examination of sputum induced by the inhalation of nebulized hypertonic saline in the diagnosis of Pneumocystis carinii pneumonia (PCP) are presented. In suspected cases of PCP in patients who were either HIV antibody positive or were receiving immunosuppressive therapy, 46 induced sputum specimens were stained using both Grocott's modified Gomori methenamine silver nitrate (GMS) and immunofluorescence staining. In 12 specimens P. carinii cysts were detected by both methods, in four specimens by GMS staining only and in five specimens by immunofluorescence only. The sensitivity of induced sputum examination in the detection of P. carinii cysts was increased by using both of these staining methods on each sputum specimen and the need for more invasive methods of diagnosis was reduced.     

Bacteriophage Ø105clz induces the GroEL-homologue protein inBacillus subtilis

Using two-dimensional polyacrylamide gel electrophoresis, the GroEL homologue ofBacillus subtilis was shown to be induced upon infection with Ø105clz, a clear plaque mutant of the temperate bacteriophage Ø105. Western blotting of one dimensional polyacrylamide gels also showed the induction of the GroEL homologue when cells were infected with Ø105clz.     

INTRASPECIFIC VARIATION AND THE ROLE OF SUPERPARASITISM IN DIAPAUSE INDUCTION OF TRICHOGRAMMA EVANESCENS WEST-WOOD*

Abstract The diapause of two populations of Trichogramma evanescens Westwood (T. evanescens A and T. evanescens B), collected from different Iranian insect pests, was studied. T. evunescens A in the eggs of Corcyra cephalonica was easily induced to stable diapause with constant 8°C, 15 % and fluctuating temperature (11–23) C -11C. T. evanescens B could not be induced to diapause with the same temperatural regime and host. The experiments showed that the host of maternal generations and the ability of avoiding super-parasitism may play an important role in intraspecific variation of T. evunescens in diapause induction.     

Fluctuation of algal alkaline phosphatase activity and the possible mechanisms of hydrolysis of dissolved organic phosphorus in Lake Barato

For freshwater cyanobacteria, the autofluorescence of phycocyanin is quite high while the in vivo fluorescence (IVF) yield of chlorophyll-a is relatively low, apparently because of low chlorophyll concentrations associated with photosystem II. In eucaryotic phytoplankton, even those with phycobili-protein accessory pigments (e.g. some cryptophytes), the opposite is true. Thus, an IVF ratio which relates phycocyanin to chlorophyll-a signals could be a good index of relative cyanobacterial abundance in the field. Spectrofluorometric scans of whole cells from laboratory cultures indicated that the ratio Em₆₆₀ @ Ex₆₃₀/Em₆₈₀ @ Ex₄₃₀ could be a very sensitive cyanobacterial indicator. Tandem flowthrough fluorometers were then fitted with the appropriate interference filters and their discriminatory power was evaluated with mixtures of cyanobacterial and eucaryotic phytoplankton. Although subject to many of the constraints of other IVF assays, tandem fluorometry should be particularly appropriate for real-time mapping of the relative spatial and temporal distributions of broad phytoplankton taxa in continuous vertical of horizontal profiles in lakes.     

Survey of chemical speciation of trace elements using synchrotron radiation

Information concerning the chemical state of trace elements in biological systems generally has not been available. Such information for toxic elements and metals in metalloproteins could prove extremely valuable in the elucidation of their metabolism and other biological processes. The shielding of core electrons by binding electrons affect the energy required for creating inner-shell holes. Furthermore, the molecular binding and symmetry of the local environment of an atom affect the absorption spectrum in the neighborhood of the absorption edge. X-ray absorption near-edge structure (XANES) using synchrotron radiation excitation can be used to provide chemical speciation information for trace elements at concentrations as low as 10 ppm. The structure and position of the absorption curve in the region of an edge can yield vital data about the local structure and oxidation state of the trace element in question. Data are most easily interpreted by comparing the observed edge structure and position with those of model compounds of the element covering the entire range of possible oxidation states. Examples of such analyses will be reviewed.