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Displaying publications 21 - 27 of 27 in total

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Clostridium bifermentans serovar malaysia: sporulation, biogenesis of inclusion bodies and larvicidal effect on mosquito

Charles JF, Nicolas L, Sebald M, de Barjac H

Res. Microbiol., 1990 7 1;141(6):721-33.
PMID: 1980958

Sporulation of Clostridium bifermentans serovar malaysia, which has a larvicidal activity towards mosquitoes, was examined by electron microscopy. Parasporal inclusion bodies lacking a crystalline structure were first detected at t5 (5 h after the end of exponentional growth). Also, the presence of "brush-bottle"-like appendages appearing first at t5 was noted; these remained attached to the spores when released after sporangium lysis. Larvicidal activity assayed on Anopheles stephensi larvae appeared at t0 and increased rapidly to a maximum between t5 and t8. However, a decrease in bacterial toxicity occurred with sporangium lysis.

Matched MeSH terms: Cell Division/physiology
The role of CD30, CD40 and CD95 in the regulation of proliferation and apoptosis in classical Hodgkin's lymphoma

Kim LH, Eow GI, Peh SC, Poppema S

Pathology, 2003 Oct;35(5):428-35.
PMID: 14555388

AIMS: CD30, CD40 and CD95 are members of the tumour necrosis factor receptor superfamily. Ligation to their respective ligands (CD30L, CD40L, CD95L) will generate a diverse set of signalling cascades. We aim to study the expression pattern of CD30, CD40 and CD95 in classical Hodgkin's lymphoma (cHL) and to correlate the expressions with proliferation and apoptosis in the Hodgkin/Reed-Sternberg (H/RS) cells of cHL with or without associated Epstein-Barr virus (EBV) infection.
METHODS: A total of 66 cHL cases were retrieved from the archives. Expressions of CD30, CD40, CD95 and proliferation by Ki-67 expression were detected with an immunohistochemical staining method. Apoptosis index was assessed by in situ TUNEL staining technique on 30 randomly selected cases and the presence of EBV was determined by EBER in situ hybridisation.
RESULTS: Expression of CD30, CD40 and CD95 in the H/RS cells was observed in a high proportion of the cases (100, 93.9, 90.5%, respectively). There was no significant association or correlation of the expression of these molecules with the presence of EBV. Expression of CD40 was associated with expression of the proliferation marker Ki-67 (P=0.044), whereas strong (intermediate and high) expression of CD30 showed a significant correlation with proliferation in the EBV-negative cases only (P=0.025). No correlation was observed for the expression of CD30 and CD40 with apoptosis of the H/RS cells. The childhood cases showed weaker CD95 expression in the H/RS cells than the adult cases, and the expression of CD95 was weaker than that of CD40 in the childhood group.
CONCLUSIONS: Our results showed that CD30, CD40 and CD95 are highly expressed in the H/RS cells of the majority of cases of cHL. The expression patterns seem to be independent of EBV and do not correlate with apoptosis of the H/RS cells.

Matched MeSH terms: Cell Division/physiology
Proteasomal degradation of p130 facilitate cell cycle deregulation and impairment of cellular differentiation in high-risk Human Papillomavirus 16 and 18 E7 transfected cells

Gandhi S, Nor Rashid N, Mohamad Razif MF, Othman S

Mol Biol Rep, 2021 Jun;48(6):5121-5133.
PMID: 34169395 DOI: 10.1007/s11033-021-06509-4

The High-Risk Human Papillomaviruses (HR-HPVs) 16 and 18 are known to cause cervical cancer, which is primarily attributed to E6 and E7 oncoproteins. In addition, recent studies have focused on the vital role of the p130 pocket protein as an oncosuppressor to limit the expression of E2F transcription factors required for cell cycle progression. In view of this, the current study was conducted to investigate the mechanism by which transfection with HPV16/18 E7 leads to the deregulation of the host cell cycle, altering the localisation of p130, and expression of differentiation genes in Human Keratinocytes (HaCaT) cells. Co-immunoprecipitation, Western blot analysis, immunofluorescence microscopy, flow cytometry, quantitative-Polymerase Chain Reaction (qPCR), and the inhibition of p130 by MG132 inhibitor were employed to investigate the loss of p130 and its disruption in HPV 16/18 E7-transfected HaCaT cells. The HPV16- and HPV18-transformed cells, known as CaSki and HeLa, respectively, were also used to complement the ectopic expressions of E7 in HaCaT cells. Normal keratinocytes displayed higher level of p130 expression than HPV-transformed cells. In addition, the immunofluorescence analysis revealed that both HPV 16/18 E7-transfected HaCaT and HPV-transformed cells exhibited higher level of cytoplasmic p130 compared to nuclear p130. A significant increase in the number of S/G2 phase cells in HPV-transformed cells was also recorded since E7 has been shown to stimulate proliferation through the deactivation of Retinoblastoma Protein (pRB)-dependent G1/S checkpoint. Furthermore, the findings recorded the down-regulation of keratinocyte differentiation markers, namely p130, keratin10, and involucrin. The proteasomal degradation of the exported p130 confirmed the cellular localisation pattern of p130, which was commonly observed in cancerous cells. The findings provide strong evidence that the localisation of nuclear p130 nuclear was disrupted by HPV16/18 E7 led to the deregulation of the cell cycle and the impairment of cellular differentiation ultimately lead to cellular transformation.

Matched MeSH terms: Cell Division/physiology
Fulltext Human peripheral blood derived mesenchymal stem cells demonstrate similar characteristics and chondrogenic differentiation potential to bone marrow derived mesenchymal stem cells

Chong PP, Selvaratnam L, Abbas AA, Kamarul T

J Orthop Res, 2012 Apr;30(4):634-42.
PMID: 21922534 DOI: 10.1002/jor.21556

The use of mesenchymal stem cells (MSCs) for cartilage repair has generated much interest owing to their multipotentiality. However, their significant presence in peripheral blood (PB) has been a matter of much debate. The objectives of this study are to isolate and characterize MSCs derived from PB and, compare their chondrogenic potential to MSC derived from bone marrow (BM). PB and BM derived MSCs from 20 patients were isolated and characterized. From 2 ml of PB and BM, 5.4 ± 0.6 million and 10.5 ± 0.8 million adherent cells, respectively, were obtained by cell cultures at passage 2. Both PB and BM derived MSCs were able to undergo tri-lineage differentiation and showed negative expression of CD34 and CD45, but positively expressed CD105, CD166, and CD29. Qualitative and quantitative examinations on the chondrogenic potential of PB and BM derived MSCs expressed similar cartilage specific gene (COMP) and proteoglycan levels, respectively. Furthermore, the s-GAG levels expressed by chondrogenic MSCs in cultures were similar to that of native chondrocytes. In conclusion, this study demonstrates that MSCs from PB maintain similar characteristics and have similar chondrogenic differentiation potential to those derived from BM, while producing comparable s-GAG expressions to chondrocytes.

Matched MeSH terms: Cell Division/physiology
Potent antibacterial activity of halogenated metabolites from Malaysian red algae, Laurencia majuscula (Rhodomelaceae, Ceramiales)

Vairappan CS

Biomol. Eng., 2003 Jul;20(4-6):255-9.
PMID: 12919806

Red algae genus Laurencia (Rhodomelaceae, Ceramiales) are known to produce a wide range of chemically interesting secondary halogenated metabolites. This investigation delves upon extraction, isolation, structural elucidation and antibacterial activity of inherently available secondary metabolites of Laurencia majuscula Harvey collected from two locations in waters of Sabah, Malaysia. Two major halogenated compounds, identified as elatol (1) and iso-obtusol (2) were isolated. Structures of these compounds were determined from their spectroscopic data such as IR, 1H-NMR, 13C-NMR and optical rotation. Antibacterial bioassay against human pathogenic bacteria was conducted using disc diffusion (Kirby-Bauer) method. Elatol (1) inhibited six species of bacteria, with significant antibacterial activities against Staphylococcus epidermis, Klebsiella pneumonia and Salmonella sp. while iso-obtusol (2) exhibited antibacterial activity against four bacterial species with significant activity against K. pneumonia and Salmonella sp. Elatol (1) showed equal and better antibacterial activity compared with tested commercial antibiotics while iso-obtusol (2) only equaled the potency of commercial antibiotics against K. pneumonia and Salmonella sp. Further tests conducted using dilution method showed both compounds as having bacteriostatic mode of action against the tested bacteria.

Matched MeSH terms: Cell Division/physiology
A B-myb--DREAM complex is not critical to regulate the G2/M genes in HPV-transformed cell lines

Rashid NN, Yusof R, Watson RJ

Anticancer Res, 2014 Nov;34(11):6557-63.
PMID: 25368258

It is well-established that HPV E7 proteins, encoded by human papillomavirus (HPV) genes, frequently associated with cervical cancers bind avidly to the retinoblastoma (RB) family of pocket proteins and disrupt their association with members of the E2F transcription factor family. Our previous study showed that the repressive p130-dimerization partner, RB-like, E2F and multi-vulval class (DREAM) complex was disrupted by HPV16 E7 proteins in order to maintain the viral replication in CaSki cells. However, we would like to address whether the activator B-myb-DREAM complex is critical in regulating the replication and mitosis phase since our previous study showed increased B-myb-DREAM expression in HPV-transformed cell lines when compared to control cells.

Matched MeSH terms: Cell Division/physiology*
Inhibition of oestrone sulphatase activity in the MDA-MB-231 breast cancer cell line by breast cyst fluid from Malaysian women

Elsadig RE, Reimann K, Yip CH, Lai LC

Anticancer Res, 2001 Jul-Aug;21(4A):2693-6.
PMID: 11724341

Oestrone sulphate is a major source of active oestrogens in the breast. It is converted to oestrone by oestrone sulphatase. Breast cyst fluid (BCF) is a rich source of sex hormones and growth factors. BCF obtained from British women has been shown to inhibit oestrone sulphatase activity in the MCF-7 oestrogen-receptor-positive breast cancer cell line. The aim of the present study was to assess whether BCF obtained from Malaysian women inhibited oestrone sulphatase activity in the MCF-7 and MDA-MB-231 breast cancer cell lines. The cell lines were grown in supplemented Dulbecco's Modified Eagle Medium for 3 days, following which a 3-day incubation with sterilised BCF was carried out. At the end of the treatment period the cell monolayers were assayed for oestrone sulphatase activity and the number of cell nuclei counted on a Coulter Counter. BCF was also fractionated on a Bio-Sil SEC 125-5 column by HPLC and the effects of the fractions collected on oestrone sulphatase activity in the MDA-MB-231 cell line were assessed. All 18 samples of BCF tested inhibited cell growth in the MDA-MB-231 cell line while 8 out of 10 samples inhibited MCF-7 cell growth; 15 out of 18 BCF samples inhibited oestrone sulphatase activity in the MDA-MB-231 cell line whereas 5 out of 10 samples stimulated oestrone sulphatase activity in the MCF-7 cell line. HPLC fractions corresponding to molecular weights of > 158 kDa and 28 kDa were found to inhibit oestrone sulphatase activity in the MDA-MB-231 cell line. Further work is required to fully characterise these substances as they may have roles to play in the prevention of breast cancer.

Matched MeSH terms: Cell Division/physiology