Tracking Recovery Patterns in Acidified Lakes: A Paleolimnological Perspective

Long-term data are often lacking to effectively assess patterns of lake acidification and recovery. Fortunately, paleolimnological techniques can be used to infer past changes in lakewater acidity and related variables by means of biological indicators, such as diatom valves and chrysophyte scales, preserved in ²¹⁰Pb-dated sediment cores. We summarize paleolimnological data that we have gathered from 36 Sudbury (Ontario) and 20 Adirondack Park (New York) lakes to estimate the magnitude of lake acidification and any subsequent recovery in these lake systems. In both regions, many lakes were shown to have acidified considerably, some over two pH units, since the 1850s. Although some recovery was noted in both lake regions, Sudbury lakes generally showed larger increases in inferred lakewater pH with recent declines in sulfur emissions. Possible explanations of these differences include the greater decrease in sulfate deposition in the Sudbury area, as well as generally longer residence times of lakes in Sudbury, perhaps allowing for more in-lake alkalinity generation. In addition, Sudbury lakes generally had higher pre-industrial pH levels, suggesting that lakes with higher natural buffering capacities are more likely to recover more quickly with declines in deposition, even if they had been acidified to a great extent.     

Analysis of chromosomal aberrations in men occupationally exposed to cement dust

Cement industry is considered as a major pollution problem on account of dust and particulate matter emitted at various steps of cement manufacture. Cement dust consists of many toxic constituents. The workers who are employed in cement industries are exposed to cement dust for long periods. Therefore, it is mandatory to evaluate the mutagenic effects of occupational exposure to cement dust in such workers. In the present study, we analyzed the samples of 124 male workers including 59 smokers and 65 non-smokers who were employed in cement industry for a period of 1–17 years. For comparison, 106 controls (including 47 smokers and 59 non-smokers) of the same age group and socio-economic status were also studied. Controls had no exposure to cement dust or any known physical or chemical agent. A significant increase in the incidence of chromosomal aberrations was observed in the exposed group when compared to the control group. The results were analyzed separately for non-smokers and smokers. The chromosomal damage was more pronounced in the smokers when compared with the non-smokers both in control and exposed groups. A significant increase in the frequency of chromosomal aberrations was also observed with increase in age in both control and exposed subjects.     

Ketohexokinase: Expression and Localization of the Principal Fructose-metabolizing Enzyme

Ketohexokinase (KHK, also known as fructokinase) initiates the pathway through which most dietary fructose is metabolized. Very little is known about the cellular localization of this enzyme. Alternatively spliced KHK-C and KHK-A mRNAs are known, but the existence of the KHK-A protein isoform has not been demonstrated in vivo. Using antibodies to KHK for immunohistochemistry and Western blotting of rodent tissues, including those from mouse knockouts, coupled with RT-PCR assays, we determined the distribution of the splice variants. The highly expressed KHK-C isoform localized to hepatocytes in the liver and to the straight segment of the proximal renal tubule. In both tissues, cytoplasmic and nuclear staining was observed. The KHK-A mRNA isoform was observed exclusively in a range of other tissues, and by Western blotting, the presence of endogenous immunoreactive KHK-A protein was shown for the first time, proving that the KHK-A mRNA is translated into KHK-A protein in vivo, and supporting the suggestion that this evolutionarily conserved isoform is physiologically functional. However, the low levels of KHK-A expression prevented its immunohistochemical localization within these tissues. Our results highlight that the use of in vivo biological controls (tissues from knockout animals) is required to distinguish genuine KHK immunoreactivity from experimental artifact. (J Histochem Cytochem 57:763–774, 2009)     

Laboratory Evaluation of the Pathogenicity of Three Isolates of the Entomopathogenic Fungus Beauveria bassiana (Bals.) Vuillemin on the American Cockroach (Periplaneta americana)

Mycopesticides can be ideal for the biocontrol of cockroaches because the habitat of these insects promotes initial fungal infection and its subsequent spread. The pathogenicity of three isolates of Beauveria bassiana to the American cockroach was tested. The insects were treated in three different ways, by direct contact with spore mass, a spore-wheat flour mixture and a spray of an aqueous spore suspension. A mortality of 100% in the first treatment, 67-100% in the second treatment and 17-75% in the third treatment was observed. These results suggest that B. bassiana spore formulations in food baits can be developed for cockroaches.     

Inhibition of the puromycin reaction with benzamidine and related compounds

Incubation of mouse cells with N-methyl-N′-nitro-N-nitrosoguanidine causes a strong inhibition of DNA replication the extent of which varies with the cell line used. Analysis of the products synthesized in drug-treated cells indicates a particularly severe effect on the joining of replicons while other steps in DNA synthesis like initiation and chain elongation are much less affected. The data indicate that replicon fusion may be extremely sensitive to changes in the topology of DNA induced by the introduction of rare single-strand breaks during repair of N-methylated purines produced by incubation of cells with small amounts of the methylating agent     

In infertile women,cells from <Emphasis Type="Italic">Chlamydia trachomatis</Emphasis> infected site release higher levels of interferon-gamma,interleukin-10 and tumor necrosis factor-alpha upon heat shock protein stimulation than fertile women

Background  

The magnitude of reproductive morbidity associated with sexually transmitted Chlamydia trachomatis infection is enormous. Association of antibodies to chlamydial heat shock proteins (cHSP) 60 and 10 with various disease sequelae such as infertility or ectopic pregnancy has been reported. Cell-mediated immunity is essential in resolution and in protection to Chlamydia as well as is involved in the immunopathogenesis of chlamydial diseases. To date only peripheral cell mediated immune responses have been evaluated for cHSP60. These studies suggest cHSPs as important factors involved in immunopathological condition associated with infection. Hence study of specific cytokine responses of mononuclear cells from the infectious site to cHSP60 and cHSP10 may elucidate their actual role in the cause of immunopathogenesis and the disease outcome.