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Molecular Forms (molecular + form)

Distribution by Scientific Domains

Medical Sciences	41%
Life Sciences	41%
Chemistry	17%

Selected Abstracts

Gingival crevicular fluid laminin-5 ,2-chain levels in periodontal disease

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2006
Gülnur Emingil
Abstract Aim: Our study aimed to examine the molecular forms and gingival crevicular fluid (GCF) levels of laminin-5 ,2-chain in patients with different periodontal disease, and compare the effects of P.gingivalis trypsin-like proteinase on intact laminin-5 ,2-chain species. Methods: Eighteen patients with generalized aggressive periodontitis (G-AgP), 29 patients with chronic periodontitis (CP), 20 with gingivitis and 20 periodontally healthy subjects were included. Probing depth, clinical attachment loss, presence of bleeding on probing and plaque were recorded. Molecular forms and GCF laminin-5 ,2-chain levels and the effects of P. gingivalis trypsin-like proteinase on intact laminin-5 ,2-chain were analysed by computer-quantitated Western immunoblotting. Results: Laminin-5 ,2-chain 40 and 70 kDa fragments could be detected in all groups, in varying levels. The CP group had elevated GCF laminin-5 ,2-chain fragment levels compared with the gingivitis and healthy groups (p<0.008). The G-AgP group had GCF laminin-5 ,2-chain fragment levels similar to the gingivitis and healthy groups (p>0.008). GCF laminin-5 ,2-chain fragments differed clearly from the multiple lower molecular size fragments of P.gingivalis trypsin-laminin-5 ,2-chain proteinases. Conclusion: Increased GCF laminin-5 ,2-chain fragments in periodontitis sites with deep periodontal pocket suggest that these cleaved 40 and 70 kDa fragments could reflect the extent of the inflammatory reaction in CP. [source]

The architecture of the GroEL,GroES,(ADP)7 chaperonin complex.

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2003

Molecular forms are considered with vertices that have integral coordinates (the indices) with respect to a symmetry-adapted basis and which are left invariant by a point group of crystallographic scale-rotations (represented in this basis by invertible integral matrices). The composite form enclosing the chaperonin complex GroEL,GroES,(ADP)7 is derived and decomposed into heptagrammal forms. These are generalizations of the two-dimensional forms based on sevenfold star polygons. In the chaperonin complex, nine such heptagrammal molecular forms are found: three for each ring (trans and cis) of GroEL and three for GroES. These forms correspond to a splitting of the monomer into adjacent segments. The change in the folding of the chains in the cis ring of GroEL arising from binding to GroES leaves the chain segmentation invariant. [source]

Role of hepatitis C virus proteins (C, NS3, NS5A) in hepatic oncogenesis

HEPATOLOGY RESEARCH, Issue 1 2008
Aldona Kasprzak
In recent years, the effects of hepatitis C virus (HCV) proteins on hepatocarcinogenesis have undergone intense investigations. The potentially oncogenic proteins include at least three HCV proteins: core (C) protein, NS3, and NS5A. Several authors indicated relationships between subcellular localization, concentration, a specific molecular form of the proteins (full length, truncated, phosphorylated), the presence of specific domains (the nuclear localization signal homologous to e.g. Bcl-2) and their effects on the mechanisms linked to oncogenesis. The involvement of all the proteins has been described as being in control of the cell cycle, through interactions with key proteins of the process (p53, p21, cyclins, proliferating cell nuclear antigen), transcription factors, proto-oncogenes, growth factors/cytokines and their receptors, and proteins linked to the apoptotic process. Untilnow, the involvement of the core protein of HCV in liver carcinogenesis is the most recognized. One of the most common proteins affected by HCV proteins is the p53 tumor-suppressor protein. The p21/WAF1 gene is a major target of p53, and the effect of HCV proteins on the gene is frequently considered in parallel. The results of studies on the effects of HCV proteins on the apoptotic process are controversial. This work summarizes the information collected thus far in the field of HCV molecular virology and principal intracellular signaling pathways in which HCV oncogenic proteins are involved. [source]

Florigen (II): It is a Mobile Protein

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2007
Yuejun Yang
Abstract The true identity of florigen , the molecule(s) that migrates from leaves to apical meristem to initiate flowering , was notoriously elusive, having made it almost the "Bigfoot" of plant biology. There was never a lack of drama in the field of florigen study, and florigen researchers have once again experienced such a swing in the last two years. We wrote a minireview last year in this journal (Yu et al. 2006) to excitedly salute, among other discoveries, the notion that the flowering locus T (FT) mRNA might be the molecular form of a florigen. However, this hypothesis was challenged in a little less than two years after its initial proposition, and the original paper proposed that the FT mRNA hypothesis was retracted (Huang et al. 2005; Bohlenius et al. 2007). Interestingly enough, the FT gene previously proposed to encode a florigen was never challenged. Rather, the FT protein, instead of the FT mRNA, is now believed to migrate from leaves to the apical meristem to promote floral initiation. In this update, we will share with our readers some entertaining stories concerning the recent studies of florigen in five different plant species. In addition to the published reports referenced in this update, readers may also refer to our previous minireview and references therein for additional background information (Yu et al. 2006). [source]

Molecular epidemiology of HIV in Ghana: Dominance of CRF02_AG

JOURNAL OF MEDICAL VIROLOGY, Issue 2 2004
Lucia Fischetti
Abstract Recent studies showed the importance of CRF02_AG in West Africa, although the clinical relevance of these recombinant forms of HIV remains unknown. The present study aimed at determining the molecular diversity of HIV in Ghana and investigating the possible epidemiologic advantage of recombinant HIV-1. Plasma samples collected in 1999,2002 from two populations of HIV infected individuals (144 asymptomatic candidate blood donors and 169 AIDS patients) were studied and 249 of them were molecularly characterised in gag, pol, and env regions. Five molecular groups were identified: strains clustering with CRF02_AG in all regions (147/249 or 59%), recombinant strains clustering with CRF02_AG in one or two regions (50/249 or 20%), other subtypes, pure or recombinant, but not involving CRF02_AG (37/249 or 15%), HIV-2 (11/249 or 4.5%), and double infections (4/249 or 1.5%). There was no significant difference in the distribution of HIV-1 recombinant strains according to clinical presentation. No evidence of a significant increase in CRF02_AG prevalence between 1999 and 2002 was found. Irrespective of clinical condition, CRF02_AG is the predominant molecular form of HIV-1 in Kumasi, Ghana. J. Med. Virol. 73:158,166, 2004. © 2004 Wiley-Liss, Inc. [source]

Adiponectin changes in HCV-Genotype 4: relation to liver histology and response to treatment

JOURNAL OF VIRAL HEPATITIS, Issue 10 2009
M. Derbala
Summary., Recently, attention has been focussed on adiponectin and its changes in different types of chronic liver disease. Its relation to hepatic fibrosis and insulin resistance in post-hepatitis liver disease is not clear. The aim of this study was to clarify the adiponectin changes in genotype 4 hepatitis C virus (HCV)-infected patient in relation to liver histology and insulin resistance, and its usefulness as a predictor of hepatic fibrosis and response to treatment. Total adiponectin and its high molecular weight (HMW) form as well as insulin levels were studied in 92 chronic HCV, genotype 4 and 66 healthy control volunteers. Neither total adiponectin (r = 0.101, P = 0.220) nor HMW adiponectin (r = 0.081, P = 0.328) correlated with viral load. Total and not HMW adiponectin was significantly correlated with hepatic fibrosis and inflammation (r = 0.267, P = 0.002, r = 0.278, P < 0.001, respectively). In addition, total adiponectin (r = 0.224, P = 0.002) and HMW adiponectin (r = 0.266, P < 0.0006) significantly correlated with insulin resistance. As fibrosis did not correlate with insulin resistance (r = 0.081, P = 0.204), the correlation between total adiponectin and fibrosis was not mediated by insulin resistance. Multivariable regression analysis, (including pretreatment cases and controls) revealed that total adiponectin was significantly associated with gender, being lower among male subjects (X2 = 13.04, P = 0.0001). The multivariable regression model supported the lack of association between insulin resistance and total adiponectin levels (X2 = 1.88, P = 0.171), while non cirrhotics had significantly lower total adiponectin levels than cirrhotics (X2 = 10.90, P = 0.004) and lower level of inflammation significantly lower total adiponectin levels than more severe inflammation (X2 = 8.95, P = 0.003). Total or HMW adiponectin did not yield receiver operating characteristic (ROC) curves with area under the curve (AUC) >75%, thus the cutoff points have poor sensitivity/specificity as predictors of fibrosis. However, as a predictor of end-of-treatment response, the ROC curve of adiponectin index gave yield an AUC = 81.4%. We can conclude that total adiponectin level, in HCV genotype 4 patients, increases with progression of hepatic fibrosis regardless of insulin resistance. Its high molecular form does not have such correlation. The adiponectin changes are not related to viral load, insulin resistance or other demographic data suggesting that this change is histologically related. In spite of this, no adiponectin cutoff level had reasonable sensitivity/specificity for predicting hepatic fibrosis stage, while this may be used as a predictor for antiviral response possibly reflecting improvement in hepatic inflammation post treatment. [source]

Molecular cloning and sequence analysis of an ascidian egg ,-N-acetylhexosaminidase with a potential role in fertilization

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2003
Ryo Koyanagi
,-N-Acetylhexosaminidase, which is found almost ubiquitously in sperm of invertebrates and vertebrates, supposedly mediates a carbohydrate-based transient sperm,egg coat binding. In ascidians and mammals, ,-hexosaminidase released at fertilization from eggs has been proposed to modify sperm receptor glycoproteins of the egg envelope, thus setting up a block to polyspermy. Previously, it was shown that in potential sperm receptor glycoproteins of the ascidian Phallusia mammillata, N-acetylglucosamine is the prevailing glycoside residue and that the egg harbors three active molecular forms of ,-hexosaminidase. In the present study, P. mammillata,-hexosaminidase cDNA was isolated from an ovarian cDNA library and characterized. The deduced amino acid sequence showed a high similarity with other known ,-hexosaminidases; however, P. mammillata,-hexosaminidase had a unique potential N-glycosylation site. A phylogenetic analysis suggested that P. mammillata,-hexosaminidase developed independently after having branched off from the common ancestor gene of the chordate enzyme before two isoforms of the mammalian enzyme appeared. In situ hybridization revealed stage-specific expression of ,-hexosaminidase mRNA during oogenesis in the oocyte and in the accessory test and follicle cells. This suggests that the three egg ,-hexosaminidase forms are specific for the oocyte, test cells and follicle cells. [source]

Immune modulation of HLA-G dimer in maternal-fetal interface

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2007
Kimiko Kuroki
Abstract HLA-G is a non-classical human MHC class I molecule, which has several characteristics distinct from classical MHC, such as low polymorphism and restricted tissue distribution. HLA-G is expressed on placenta, thymus and some tumors. At the maternal-fetal interface, trophoblasts do not express major classical MHC class I molecules (MHCI), HLA-A and -B, to prevent normal T cell responses. Instead, HLA-G is expressed and can suppress a wide range of immune responses by binding to inhibitory immune cell surface receptors, such as leukocyte Ig-like receptor (LILR) B1 and LILRB2. HLA-G exists in various forms, including ,2m-associated or -free disulfide-linked dimers that can be expressed either at the cell surface or in soluble form. However, until recently the physiological role of these different molecular forms has been unclear. In this issue of the European Journal of Immunology, one article demonstrates that the disulfide-linked homodimer of ,2m-associated HLA-G is the major fraction expressed by trophoblast cells. The HLA-G dimer modulates the function of LILRB1-expressing antigen-presenting cells by principally binding to LILRB1. On the other hand, another recent report showed that ,2m-free disulfide-linked HLA-G dimers are produced by villous cytotrophoblast cells. Taken together, these results provide strong evidence in support of the hypothesis that HLA-G dimers play a role in immune suppression at the maternal-fetal interface. Further in-depth investigation will help to clarify the precise mechanism of HLA-G receptor recognition and signaling in vivo and the role of these interactions in successful reproduction. See accompanying article: http://dx.doi.org/10.1002/eji.200737089 [source]

Expression of PRiMA in the mouse brain: membrane anchoring and accumulation of ,tailed' acetylcholinesterase

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2003
Noël A. Perrier
Abstract We analysed the expression of PRiMA (proline-rich membrane anchor), the membrane anchor of acetylcholinesterase (AChE), by in situ hybridization in the mouse brain. We compared the pattern of PRiMA transcripts with that of AChE transcripts, as well as those of choline acetyltransferase and M1 muscarinic receptors which are considered pre- and postsynaptic cholinergic markers. We also analysed cholinesterase activity and its molecular forms in several brain structures. The results suggest that PRiMA expression is predominantly or exclusively related to the cholinergic system and that anchoring of cholinesterases to cell membranes by PRiMA represents a limiting factor for production of the AChE tailed splice variant (AChET),PRiMA complex, which represents the major AChE component in the brain. This enzyme species is mostly associated with cholinergic neurons because the pattern of PRiMA mRNA expression largely coincides with that of ChAT. We also show that, in both mouse and human, PRiMA proteins exist as two alternative splice variants which differ in their cytoplasmic regions. [source]

SINE insertion polymorphism on the X chromosome differentiates Anopheles gambiae molecular forms

INSECT MOLECULAR BIOLOGY, Issue 4 2005
M. J. Barnes
Abstract Polymorphic SINE insertions can be useful markers for assessing population structure and differentiation. Maque is a family of SINE elements which, based on bioinformatic analysis, was suggested to have been active recently in Anopheles gambiae, the major vector of malaria. Here, we report the development of polymorphic Maque insertions as population genetic markers in A. gambiae, and the use of these markers to better characterize divergence on the X chromosome between A. gambiae M and S molecular forms in populations from Burkina Faso and Mali. Our data are consistent with the recent activity of Maque. Phylogenetic analysis suggests that at least two recently active lineages may have a role in mediating genome evolution. We found differences in element insertion frequency and sequence between the M and S populations analysed. Significant differentiation was observed between these two groups across a 6 Mb region at the proximal (centromeric) end of the X chromosome. Locus-specific FST values ranged from 0.14 to 1.00 in this region, yet were not significantly different from zero in more distal locations on the X chromosome; the trend was consistent in populations from both geographical locales suggesting that differentiation is not due to local adaptation. Strong differentiation between M and S at the proximal end of the X chromosome, but not outside this region, suggests the action of selection counteracting limited gene flow between these taxa and supports their characterization as incipient species. [source]

Evaluation of molecular forms of prostate-specific antigen and human kallikrein 2 in predicting biochemical failure after radical prostatectomy

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2009
Sven Wenske
Abstract Most pretreatment risk-assessment models to predict biochemical recurrence (BCR) after radical prostatectomy (RP) for prostate cancer rely on total prostate-specific antigen (PSA), clinical stage, and biopsy Gleason grade. We investigated whether free PSA (fPSA) and human glandular kallikrein-2 (hK2) would enhance the predictive accuracy of this standard model. Preoperative serum samples and complete clinical data were available for 1,356 patients who underwent RP for localized prostate cancer from 1993 to 2005. A case-control design was used, and conditional logistic regression models were used to evaluate the association between preoperative predictors and BCR after RP. We constructed multivariable models with fPSA and hK2 as additional preoperative predictors to the base model. Predictive accuracy was assessed with the area under the ROC curve (AUC). There were 146 BCR cases; the median follow up for patients without BCR was 3.2 years. Overall, 436 controls were matched to 146 BCR cases. The AUC of the base model was 0.786 in the entire cohort; adding fPSA and hK2 to this model enhanced the AUC to 0.798 (p = 0.053), an effect largely driven by fPSA. In the subgroup of men with total PSA ,10 ng/ml (48% of cases), adding fPSA and hK2 enhanced the AUC of the base model to a similar degree (from 0.720 to 0.726, p = 0.2). fPSA is routinely measured during prostate cancer detection. We suggest that the role of fPSA in aiding preoperative prediction should be investigated in further cohorts. © 2008 Wiley-Liss, Inc. [source]

Gingival crevicular fluid laminin-5 ,2-chain levels in periodontal disease

Selective enhancement of the activity of C-terminally truncated, but not intact, acetylcholinesterase

JOURNAL OF NEUROCHEMISTRY, Issue 1 2008
Martina Zimmermann
Abstract Acetylcholinesterase (AChE) is one of the fastest enzymes approaching the catalytic limit of enzyme activity. The enzyme is involved in the terminal breakdown of the neurotransmitter acetylcholine, but non-enzymatic roles have also been described for the entire AChE molecule and its isolated C-terminal sequences. These non-cholinergic functions have been attributed to both the developmental and degenerative situation: the major form of AChE present in these conditions is monomeric. Moreover, AChE has been shown to lose its typical characteristic of substrate inhibition in both development and degeneration. This study characterizes a form of AChE truncated after amino acid 548 (T548-AChE), whose truncation site is homologue to that of a physiological form of T-AChE detected in fetal bovine serum that has lost its C-terminal moiety supposedly due to proteolytic cleavage. Peptide sequences covered by this C-terminal sequence have been shown to be crucially involved in both developmental and degenerative mechanisms in vitro. Numerous studies have addressed the structure,function relationship of the AChE C-terminus with T548-AChE representing one of the most frequently studied forms of truncated AChE. In this study, we provide new insight into the understanding of the functional characteristics that T548-AChE acquires in solution: T548-AChE is incubated with agents of varying net charge and molecular weight. Together with kinetic studies and an analysis of different molecular forms and aggregation states of T548-AChE, we show that the enzymatic activity of T548-AChE, an enzyme verging at its catalytic limit is, nonetheless, apparently enhanced by up to 800%. We demonstrate, first, how the activity of T548-AChE can be enhanced through agents that contain highly positive charged moieties. Moreover, the un-competitive mechanism of activity enhancement most likely involves the peripheral anionic site of AChE that is reflected in delayed substrate inhibition being observed for activity enhanced T548-AChE. The data provides evidence towards a mechanistic and functional link between the form of AChE unique to both development and degeneration and a C-terminal peptide of T-AChE acting under those conditions. [source]

Altered glycosylation of acetylcholinesterase in Creutzfeldt,Jakob disease

JOURNAL OF NEUROCHEMISTRY, Issue 1 2006
María-Ximena Silveyra
Abstract Changes in the glycosylation pattern of brain proteins have been associated with Creutzfeldt,Jakob disease (CJD). We have investigated the glycosylation status of acetylcholinesterase (AChE) by lectin binding assay. Our data show that in lumbar CSF from definite and probable sporadic CJD cases AChE activity is lower compared with that in age-matched controls. We also show, for the first time, that AChE glycosylation is altered in CJD CSF and brain. Unlike Alzheimer's disease, in which an alteration in both the glycosylation and levels of AChE molecular forms is observed, the abnormal glycosylation of AChE in CJD appears to be unrelated to changes in molecular forms of this enzyme. These findings suggest that altered AChE glycosylation in CJD may be a consequence of the general perturbation of the glycosylation machinery that affects prion protein, as well as other proteins. The diagnostic potential of these changes remains to be explored. [source]

Matrix metalloproteinase-7, -8, -9, -25, and -26 and CD43, -45, and -68 cell-markers in HIV-infected patients' saliva and gingival tissue

JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2006
Liisa Mellanen
Background:, Matrix metalloproteinases (MMPs) process the extracellular matrix and act in tissue remodelling in many physiological and pathological conditions. Certain MMPs can also exert protective anti-inflammatory properties. The levels and expression of MMPs and tissue inhibitors of MMPs (TIMPs) in saliva and gingival tissues of human immunodeficiency virus-seropositive (HIV+) patients are unclear. Methods:, Enzyme-linked immunosorbent assay methods and Western blots were used to study levels and molecular forms of MMP-7, -8, -9, -25, and -26 and TIMP-1 from salivary samples of HIV+ patients (n = 55) and healthy controls (n = 10). The expression of MMPs was also studied by immunohistochemical means in gingival tissue specimens (n = 11, HIV+ patients; n = 10, healthy controls). Results:, The HIV+ patients' MMP-8 levels in saliva were statistically significantly higher only in the acquired immunodeficiency syndrome (AIDS)-phase. MMP-9 levels in ASX- and AIDS-phases showed increased expression. TIMP-1 levels were significantly decreased in lymphadenopathy syndrome (LAS)- and AIDS-related complex (ARC)-phases, while MMP-8/TIMP-1 and MMP-9/TIMP-1 molar ratios were increased in all phases in comparison with controls. The molecular forms of MMP-7, -25, and -26 were different between patients and controls as assessed by Western blot. Immunohistochemical studies showed slightly enhanced MMP-7, -8, -9, -25, and -26 staining in HIV+ gingival tissue samples in comparison with controls. Conclusions:, This study confirmed and further demonstrated differences in salivary amounts and molecular forms of MMPs and TIMP-1 in HIV+ patients. The results may reflect alterations in host defence reactions associated with HIV infection. [source]

STEROID EFFECTS ON THE GENE EXPRESSION OF PERIPHERAL MYELIN PROTEINS

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2002
RC Melcangi
The present article summarizes recent observations obtained in our laboratory which clearly indicate that sex steroids exert relevant effects on the peripheral nervous system. In particular, the following important points have emerged: (1) Steroids exert stimulatory actions on the synthesis of the proteins proper of the peripheral myelin (e.g., glycoprotein Po and peripheral myelin protein 22) in vivo and on the Schwann cells in culture; (2) in many cases the actions of hormonal steroids are not due to their native molecular forms but rather to their metabolites (e.g., dihydroprogesterone and tetrahydroprogesterone in the case of progesterone; dihydrotestosterone and 5 alpha-androstane-3 alpha,17 beta -diol in the case of testosterone); (3) the mechanism of action of the various steroidal molecules may involve both classical (progesterone and androgen receptors) and nonclassical steroid receptors (GABA, receptor); and finally, (4) the stimulatory action of steroid hormones on the proteins of the peripheral myelin might have clinical significance in cases in which the rebuilding of myelin is needed (e.g., aging, peripheral injury, demyelinating diseases, and iabetic neuropathy). [source]

Pyrethroid resistance/susceptibility and differential urban/rural distribution of Anopheles arabiensis and An. gambiae s.s. malaria vectors in Nigeria and Ghana

MEDICAL AND VETERINARY ENTOMOLOGY, Issue 3 2003
M. Kristan
Abstract., Resistance to pyrethroid insecticides and DDT caused by the kdr gene in the malaria vector Anopheles gambiae Giles s.s. (Diptera: Culicidae) has been reported in several West African countries. To test for pyrethroid resistance in two more countries, we sampled populations of the An. gambiae complex from south-western Ghana and from urban and rural localities in Ogun State, south-west Nigeria. Adult mosquitoes, reared from field-collected larvae, were exposed to the WHO-recommended discriminating dosage of exposure for 1 h to DDT 4%, deltamethrin 0.05% or permethrin 0.75% and mortality was recorded 24 h post-exposure. Susceptibility of An. gambiae s.l. to DDT was 94,100% in Ghana and 72,100% in Nigeria, indicating low levels of DDT resistance. Deltamethrin gave the highest mortality rates: 97,100% in Ghana, 95,100% in Nigeria. Ghanaian samples of An. gambiae s.l. were fully susceptible to permethrin, whereas some resistance to permethrin was detected at 4/5 Nigerian localities (percentage mortalities 75, 82, 88, 90 and 100%), with survivors including both An. arabiensis Patton and An. gambiae s.s. identified by PCR assay. Even so, the mean knockdown time was not significantly different from a susceptible reference strain, indicating absence or low frequency of kdr -type resistance. Such low levels of pyrethroid resistance are unlikely to impair the effectiveness of pyrethroid-impregnated bednets against malaria transmission. Among Nigerian samples of An. gambiae s.l., the majority from two urban localities were identified as An. arabiensis, whereas the majority from rural localities were An. gambiae s.s. These findings are consistent with those of M. Coluzzi et al. (1979). Differences of ecological distribution between molecular forms of An. gambiae s.s. were also found, with rural samples almost exclusively of the S-form, whereas the M-form predominated in urban samples. It is suggested that ,urban island' populations of An. arabiensis and of An. gambiae s.s. M-form in the rainforest belt of West Africa might be appropriate targets for elimination of these malaria vectors by the sterile insect technique. [source]

DNA analysis of transferred sperm reveals significant levels of gene flow between molecular forms of Anopheles gambiae

MOLECULAR ECOLOGY, Issue 7 2001
F. Tripet
Abstract Anopheles gambiae populations in west Africa are complex, being composed of multiple, sympatric subpopulations. Recent studies have failed to reveal significant genetic differences among subpopulations, stimulating a debate regarding the levels of gene flow among them. The observed homogeneity may be the consequence of substantial contemporary gene flow or it may be that reproductive isolation is complete, but too recent for the accumulation of significant levels of genic divergence. Here, we report the results of a study estimating contemporary levels of gene flow between An. gambiae subpopulations by analysing females and transferred sperm removed from their reproductive systems. A total of 251 female and associated sperm extracts was analysed from a single site in Mali. Two molecular forms of An. gambiae, the M- and S-forms, occurred in sympatry at this site. Overall, we found very strong positive assortative mating within forms, however, we did observe significant hybridization between forms. In the M subpopulation 2/195 females (1.03%) contained sperm from S-form males and in 55 S-form females we found one female containing M-form sperm (1.82%). We also identified a mated M ×S hybrid adult female. From mating frequencies, we estimate the Nem between the M- and S-form at 16.8, and from the adult hybrid frequency at 5.6. These values are consistent with our earlier estimate, based on FST for 21 microsatellite loci in which Nem = 5.8. We conclude that the general lack of genetic divergence between the M and S subpopulations of An. gambiae can be explained entirely by contemporary gene flow. [source]

Determination of the disulfide bond pattern of the endogenous and recombinant angiogenesis inhibitor endostatin by mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2001
Harald John
Endostatin, a C-terminal fragment of collagen XVIII, is a promising protein drug which is in development for cancer therapy due to its anti-angiogenic activity. Although several endogenous molecular forms of human endostatin differing in their N-terminal length and their post-translational modifications (18.5,22,kDa) have been discovered, only one recombinant form of 20,kDa is used in clinical trials. This protein, recombinantly expressed in Pichia pastoris, contains four cysteines forming two disulfide bonds (Cys1-Cys4 and Cys2-Cys3). In contrast, there are conflicting data about the disulfide pattern of endogenous material. This report presents the disulfide analyses of both the endogenous circulating endostatins isolated from human hemofiltrate and the recombinant protein. The determination of the disulfide pattern was performed by Edman degradation, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and electrospray ionization ion trap mass spectrometry (ESI-ITMS) performed in the off-line nanospray mode. All native and recombinant endostatins exhibited a Cys1-Cys4 (Cys162 -Cys302) and Cys2-Cys3 (Cys264 -Cys294) linkage. For a clear discussion of fragmented disulfide-bridged peptide chains obtained from MSn experiments, a modified general nomenclature is proposed. Copyright © 2001 John Wiley & Sons, Ltd. [source]

The architecture of the GroEL,GroES,(ADP)7 chaperonin complex.

Crystallization and preliminary X-ray crystallographic studies of an exo-,- d -glucosaminidase from Trichoderma reesei

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2010
Yasumitsu Sakamoto
Chitosan is degraded to glucosamine (GlcN) by chitosanase and exo-,- d -glucosaminidase (GlcNase). GlcNase from Trichoderma reesei (Gls93) is a 93,kDa extracellular protein composed of 892 amino acids. The enzyme liberates GlcN from the nonreducing end of the chitosan chain in an exo-type manner and belongs to glycoside hydrolase family 2. For crystallographic investigations, Gls93 was overexpressed in Pichia pastoris cells. The recombinant Gls93 had two molecular forms of ,105,kDa (Gls93-F1) and ,100,kDa (Gls93-F2), with the difference between them being caused by N-glycosylation. Both forms were crystallized by the hanging-drop vapour-diffusion method. Crystals of Gls93-F1 belonged to the orthorhombic space group P212121, with unit-cell parameters a = 98.27, b = 98.42, c = 108.28,Å, and diffracted to 1.8,Å resolution. Crystals of Gls93-F2 belonged to the orthorhombic space group P212121, with unit-cell parameters a = 67.84, b = 81.62, c = 183.14,Å, and diffracted to 2.4,Å resolution. Both crystal forms were suitable for X-ray structure analysis at high resolution. [source]

Chaperone-like activities of different molecular forms of ,-casein.

BIOPOLYMERS, Issue 8 2009
Importance of polarity of N-terminal hydrophilic domain
Abstract As a member of intrinsically unstructured protein family, ,-casein (,-CN) contains relatively high amount of prolyl residues, adopts noncompact and flexible structure and exhibits chaperone-like activity in vitro. Like many chaperones, native ,-CN does not contain cysteinyl residues and exhibits strong tendencies for self-association. The chaperone-like activities of three recombinant ,-CNs wild type (WT) ,-CN, C4 ,-CN (with cysteinyl residue in position 4) and C208 ,-CN (with cysteinyl residue in position 208), expressed and purified from E. coli, which, consequently, lack the phosphorylated residues, were examined and compared with that of native ,-CN using insulin and alcohol dehydrogenase as target/substrate proteins. The dimers (,-CND) of C4-,-CN and C208 ,-CN were also studied and their chaperone-like activities were compared with those of their monomeric forms. Lacking phosphorylation, WT ,-CN, C208 ,-CN, C4 ,-CN and C4 ,-CND exhibited significantly lower chaperone-like activities than native ,-CN. Dimerization of C208 ,-CN with two distal hydrophilic domains considerably improved its chaperone-like activity in comparison with its monomeric form. The obtained results demonstrate the significant role played by the polar contributions of phosphorylated residues and N-terminal hydrophilic domain as important functional elements in enhancing the chaperone-like activity of native ,-CN. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 623,632, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]

Changes in molecular forms of prostate-specific antigen during treatment with finasteride

BJU INTERNATIONAL, Issue 7 2002
F. España
Objective ,To study the influence of finasteride treatment on the molecular forms of prostate-specific antigen (PSA) in patients with benign prostatic hyperplasia (BPH). Patients and methods ,Total PSA, free PSA and PSA complexed to ,1 -antichymotrypsin (PSA-,1ACT) were measured in plasma and serum from 40 men with BPH and a total PSA of <,20 ng/mL, using in-house and commercial immunoassays, before and during treatment with finasteride (30 men) or placebo (10 men). Results ,The baseline values were not significantly different between the groups, with mean (sd) total plasma PSA levels of 3.6 (4.3) and 4.8 (5.9) ng/mL in the finasteride and placebo groups, respectively. Finasteride, but not placebo, induced a significant reduction in total PSA, free PSA and PSA-,1ACT levels in plasma and serum (P < 0.001). However, complexed-to-total (c/t) and free-to-total (f/t) PSA ratios remained constant in both groups, both in plasma and serum, during the follow-up. Conclusion ,The decrease in total PSA after finasteride treatment results from a proportional reduction in its two major molecular forms, free PSA and PSA-,1ACT, which explains why the c/t and f/tPSA ratios do not change significantly despite treatment. This suggests that routine analysis of molecular forms of PSA could improve the utility of the change in total PSA associated with finasteride for the early diagnosis of prostate cancer. It also suggests that any subsequent change in both ratios, particularly an increase in c/tPSA or a decrease in f/tPSA ratio, could be considered an early sign of neoplastic degeneration rather than a therapeutic consequence. [source]

Unique macrophage and tick cell-specific protein expression from the p28/p30-outer membrane protein multigene locus in Ehrlichia chaffeensis and Ehrlichia canis

CELLULAR MICROBIOLOGY, Issue 9 2006
Vijayakrishna Singu
Summary Ehrlichia chaffeensis and Ehrlichia canis are tick-transmitted rickettsial pathogens that cause human and canine monocytic ehrlichiosis respectively. We tested the hypothesis that these pathogens express unique proteins in response to their growth in vertebrate and tick host cells and that this differential expression is similar in closely related Ehrlichia species. Evaluation of nine E. chaffeensis isolates and one E. canis isolate demonstrated that protein expression was host cell-dependent. The differentially expressed proteins included those from the p28/30-Omp multigene locus. E. chaffeensis and E. canis proteins expressed in infected macrophages were primarily the products of the p28-Omp 19 and 20 genes or their orthologues. In cultured tick cells, E. canis expressed only the p30-10 protein, an orthologue of the E. chaffeensis p28-Omp 14 protein which is the only protein expressed by E. chaffeensis propagated in cultured tick cells. The expressed Omp proteins were post-translationally modified to generate multiple molecular forms. E. chaffeensis gene expression from the p28/30-Omp locus was similar in tick cell lines derived from both vector (Amblyomma americanum) and non-vector (Ixodes scapularis) ticks. Differential expression of proteins within the p28/p30-Omp locus may therefore be vital for adaptation of Ehrlichia species to their dual host life cycle. [source]

Novel B and T cell epitopes of chicken ovomucoid (Gal d 1) induce T cell secretion of IL-6, IL-13, and IFN-,

CLINICAL & EXPERIMENTAL ALLERGY, Issue 6 2001
E. Holen
Background Chicken ovomucoid (OM, Gal d 1) has an important role in the pathogenesis of IgE-mediated allergic reactions to hen's egg white. Objectives The purpose of this study was to clarify the mechanisms of T cell recognition of ovomucoid using intact OM and chemically modified, characterized and homogeneous solid phase synthetic peptides covering the whole molecule. Methods Eighteen overlapping peptides were prepared by solid phase F-moc polyamide peptide synthesis (SPPS), characterized and high-pressure liquid chromatography (HPLC) purified. The peptides, together with intact, denatured and oxidized OM, were used to stimulate patient-derived cell cultures for mapping T cell epitopes. Proliferation responses, T cell phenotype and cytokine secretion using peripheral blood mononuclear cells (PBMC) from eight individuals and T cell lines (TCL) derived from six hen's egg-allergic patients, were examined. In addition, intact, denatured, oxidized and deglycosylated OM, as well as the peptides solely or with their keyhole limpet haemocyanin (KLH) complexes, were tested. For locating IgE and IgG B cell epitopes, seven egg-allergic patient sera and three OM-polyclonal sera were used. Healthy non-allergic individuals were included as controls. Results Seven peptides were recognized by specific IgE, while OM-specific TCL recognized 10 peptides. Six of the OM peptides were commonly recognized both by patient S-IgE and blood-derived TCL. Among those, one novel epitope, peptide OM 61,74, had the ability to bind IgE. Another peptide, OM 101,114, was recognized by IgE and IgG sera, but not by any of the TCLs. In contrast, the peptides OM 41,56, OM 71,84, OM 131,144 and OM 171,186 were exclusively T cell epitopes with no affinity to specific antibodies. Abundant TCL secretion of IFN-,, IL-6, IL-4, IL-13, IL-10 and TNF-, in response to OM stimulation indicates the contribution of Th2 as well as Th1/Th0 CD4+ cell subsets. For allergic patients moderate amounts of IFN-,, IL-13, and high amounts of IL-6, were secreted in response to TCL stimulation by OM peptides. High amounts of IL-6 were secreted in response to all molecular forms of OM (intact-, modified-OM and the peptides 71,84 and 51,64) when TCLs from two non-allergic donors were used. Conclusions One novel B cell epitope (OM 61,74) and 10 T cell epitopes have been identified. The most reactive epitopes of the OM molecule comprise the motifs 1,14 to 71,84, the overlapping peptide-pairs OM 121,134 and OM 131,144 and peptides OM 161,174 and 171,186. Peptides OM 1,14 and 171,186 are the only ones capable of inducing IL-4 secretion. Only one peptide (OM 11,24) induces IL-10 secretion. Those peptides recognized as both T and B cell epitopes or only T cell epitopes, have the potential to induce T cell secretion of moderate to high amounts of IL-13, IFN-, and particularly IL-6. [source]