Oncocytic carcinoid tumor of the lung: a case report of diagnostic pitfall in filter membrane preparation of bronchial washings

BACKGROUND: Oncocytic carcinoid tumor of the lung is a rare variant of pulmonary carcinoid. This report describes the morphologic appearance of this rare tumor on filter membrane preparation along with potential pitfalls. CASE: A 49-year-old woman presented with cough and expectoration. On chest radiograph a mass lesion was seen in the upper zone of the right lung. Bronchial washings were sent for evaluation. On filter membrane (Millipore) preparation of bronchial washing the possibility of a non-small cell carcinoma, possibly squamous, was suggested. Right upper lobectomy was subsequently performed and a histologic diagnosis of oncocytic carcinoid given. The cytomorphologic features of this tumor on the Millipore preparation were reviewed. CONCLUSION: Differential diagnosis of oncocytic carcinoid should be kept in mind while assessing cytologic material when tumor cells show abundant granular cytoplasm and prominent nucleoli. Oncocytic carcinoid also must be differentiated from oncocytoma and granular cell tumor. Immunocytochemistry and electron microscopy are useful in confirming the diagnosis.     

Alkaline lipase production by Citrobacter freundii IIT-BT L139

Around 150 lipase producing bacterial isolates were screened from the local soils enriched with oil. Citrobacrer freundii IIT-BT L139, an isolated microbial strain, produced lipase that had high activity (8.8 U/ml) at pH 9.0 and 40 degrees C. The 16S rDNA phylogenetic studies showed that Citrobacter freundii belongs to the family Enterobacteriaceae and later confirmed by the microbial identification. Suitable C and N sources for lipase production were deduced to be starch and peptone-urea, respectively. In a controlled fermenter (1 L), the lipase activity was found to increase by 36% (12 Uml(-1)). The variation of lipase activity, pH and dissolved oxygen (DO) during growth of the organism in the controlled batch fermenter were monitored. The rheological characteristics of the fermentation broth indicated that it behaved like a Newtonian fluid throughout the fermentation. The fermentation time was comparatively short (60 h). The lipase was also found to be substantially resistant to common detergents. This lipase was, thus, characterized as alkaline, thermostable and solvent stable, which was essentially desirable in pharmaceutical, detergent and other industrial applications or production.     

Proteomic Identification of Mitochondrial Targets of Arginase in Human Breast Cancer

We have previously reported arginase expression in human breast cancer cells and demonstrated that the inhibition of arginase by N^ω hydroxy L-arginine (NOHA) in MDA-MB-468 cells induces apoptosis. However, arginase expression and its possible molecular targets in human breast tumor samples and potential clinical implications have not been fully elucidated. Here, we demonstrate arginase expression in human breast tumor samples, and several established breast cancer cell lines, in which NOHA treatment selectively inhibits cell proliferation. The over-expression of Bcl2 in MDA-MB-468 cells abolished NOHA-induced apoptosis, suggesting that the mitochondria may be the main site of NOHA’s action. We, therefore, undertook a proteomics approach to identify key mitochondrial targets of arginase in MDA-MB-468 cells. We identified 54 non-mitochondrial and 13 mitochondrial proteins that were differentially expressed in control and NOHA treated groups. Mitochondrial serine hydroxymethyltransferase (mSHMT) was identified as one of the most promising targets of arginase. Both arginase II (Arg II) and mSHMT expressions were higher in human breast tumor tissues compared to the matched normal and there was a strong correlation between Arg II and mSHMT protein expression. MDA-MB-468 xenografts had significant upregulation of Arg II expression that preceded the induction of mSHMT expression. Small inhibitory RNA (siRNA)-mediated inhibition of Arg II in MDA-MB-468 and HCC-1806 cells led to significant inhibition of both the mSHMT gene and protein expression. As mSHMT is a key player in folate metabolism, our data provides a novel link between arginine and folate metabolism in human breast cancer, both of which are critical for tumor cell proliferation.     

PUMA dependent mitophagy by Abrus agglutinin contributes to apoptosis through ceramide generation

PUMA, a BH3-only pro-apoptotic Bcl2 family protein, is known to translocate from the cytosol into the mitochondria in order to induce apoptosis. Interestingly, the induction of PUMA by p53 plays a critical role in DNA damage-induced apoptosis. In this study, we reported mitophagy inducing potential of PUMA triggered by phytolectin Abrus agglutinin (AGG) in U87MG glioblastoma cells and established AGG-induced ceramide acts as the chief mediator of mitophagy dependent cell death through activation of both mitochondrial ROS as well as ER stress. Importantly, AGG upregulates PUMA expression in U87MG cells with the generation of dysfunctional mitochondria, with gain and loss of function of PUMA is shown to alter mitophagy induction. At the molecular level, our study identified that the LC3 interacting region (LIR) located at the C-terminal end of PUMA interacts with LC3 in order to stimulate mitophagy. In addition, AGG is also found to trigger ubiquitination of PUMA which in turn interacted with p62 for prompting mitophagy suggesting that AGG turns on PUMA-mediated mitophagy in U87MG cells in both p62-dependent as well as in p62-independent manner. Interestingly, AGG-triggered ceramide production through activation of ceramide synthase–1 leads to induction of ER stress and ROS accumulation to promote mitochondrial damage as well as mitophagy. Further, upon pre-treatment with Mdivi–1, DRP1 inhibitor, AGG exposure results in suppression of apoptosis in U87MG cells indicating AGG-induced mitophagy switches to apoptosis that can be exploited for better cancer therapeutics.     

Derivation of scenario-specific water quality guidelines for acid mine drainage in South Africa,using a risk-based approach

Acid mine drainage (AMD) continues to threaten water quality in many mining regions globally. Data paucity renders it challenging to inform appropriate water quality management strategies for a succinct scientific understanding of the effects of AMD on freshwater ecosystems. The current study investigated the effects of AMD collected from a defunct coalmine in Mpumalanga, South Africa, on freshwater ecosystems using a risk-based approach on five indigenous species, Adenophlebia auriculata, Burnupia stenochorias, Caridina nilotica, Pseudokirchneriella subcapitata and Oreochromis mossambicus in 2016. Species responded differently to AMD after 96 hours and 240 hours of exposure in static experimental test designs. Burnupia stenochorias was more sensitive to AMD after 96 and 240 hours of exposure, whereas O. mossambicus was tolerant during short-term exposure, but became more sensitive after 240 hours of exposure than the other species tested. The availability of metals in AMD was directly associated with dilution rate. Scenario-specific water quality guidelines for AMD have been derived as 0.122% for short-term and 0.014% for long-term exposure. These may form important indicative dilutions for other AMDs that do not match the scenarios of this study. The toxicity of AMD to a wide range of aquatic species, including field validations, requires further investigation.     

Characterization of peptidyl-tRNA hydrolase encoded by open reading frame Rv1014c of Mycobacterium tuberculosis H37Rv

The enzyme peptidyl-tRNA hydrolase (Pth, EC 3.1.1.29) is essential for the viability of bacteria. The ORF Rv1014c of Mycobacterium tuberculosis H37Rv, designated as the mtpth gene, was cloned and over-expressed and the product was purified. Generation of polyclonal antibodies against the purified recombinant protein, termed MtPth, facilitated detection of endogenously expressed MtPth in M. tuberculosis H37Rv cell lysate. MtPth could release diacetyl-[(3)H]-lysine from diacetyl-[(3)H]-lysyl-tRNA(Lys) with Michaelis-Menten kinetic parameters of K (m)=0.7+/-0.2 microM and k (cat)=1.22+/-0.2 s(-1). Transformation of a pTrc99c/mtpth vector allowed the growth of E. coli thermosensitive Pth(ts) mutant strain AA7852 at the non-permissive temperature of 42 degrees C, demonstrating the in vivo activity of MtPth. In addition, at 39 degrees C, over-expression of MtPth in AA7852 cells allowed the cells to remain viable in the presence of up to 200 microg/ml erythromycin. A 3D fold based on NMR and a structural model based on the E. coli Pth crystal structure were generated for MtPth. The essential nature of conserved active-site residues N12, H22 and D95 of MtPth for catalysis was demonstrated by mutagenesis and complementation in E. coli mutant strain AA7852. Thermal and urea/guanidinium chloride (GdmCl)-induced unfolding curves for MtPth indicate a simple two-state unfolding process without any intermediates.     

Effect of ageing on survival of benthic diatom propagules

A comparison of viable benthic diatom propagules based on the observations recorded immediately and after 5 years of ageing at 5 °C is presented. The number of viable benthic diatom propagules decreased with ageing. However, they exhibited an apparently longer lag phase. Although diatoms belonging to the genera Amphora, Navicula and Thalassiosira were dominant during immediate observation, only Amphora and Navicula survived the ageing process. The non-viability of Thalassiosira indicates that ageing for five years was beyond its critical period of survival. The other diatom genera that survived the ageing process were Odontella and Grammatophora.