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1.
Amin T. Abadi Tarang Taghvaei Ali Ghasemzadeh Ashraf M. Mobarez 《Saudi Journal Of Gastroenterology》2011,17(6):396-399
Background/Aim:
Resistance to clarithromycin in H. pylori isolates is accepted as a main cause of treatment failure in developing countries. We aimed to determine the prevalence of clarithromycin-resistant strains isolated from dyspeptic patients in northern Iran, furthermore we aimed to assess the relationship between clinical outcomes of infection with point mutations.Materials and Methods:
A total of 147 consecutive patients infected with H. pylori were included for determining the status of resistant H. pylori strains. With upper gastroscopy, three antral biopsies were taken from each patient, first section for rapid urea test, second for pathology and third section was used for bacterial culture in microbiologic lab. The antimicrobial susceptibility tests in this examination were agar dilution, in accordance with clinical and laboratory standards institue guidelines. Restriction fragment length polymorphism-PCR (RFLP-PCR) method was applied to determine the frequency of point mutations in 23s rRNA gene. Statistical analysis was performed using SPSS software (15.0) (SPSS, Inc., Chicago, Ill). Chi-square and Fisher''s exact tests were applied to our analysis. A P value less than 5% was considered as statistically significant.Results:
Our results showed that there was no point mutation in clarithromycin-susceptible strains of H. pylori.Conclusion:
The important findings in our study indicate that A2143G is the most prevalent point mutation (30/32: 93.7%) attributed in clarithromycin resistance among the H. pylori strains. The current study concluded that clarithromycin could still be involved in the empirical treatment of H. pylori infection, although a high frequency of A2143G mutation may increase the concerns regarding treatment failure. 相似文献2.
Fascioliasis is a zoonotic infection caused by Fasciola hepatica. Humans can become accidental hosts of this parasite by ingesting contaminated drinking water or plants in endemic area. The north of Iran is one of the regions. This disease is rarely seen with jaundice caused by obstruction of the biliary tree. We report a case of human fascioliasis with obstructive jaundice who was diagnosed using endoscopic retrograde cholangiopancreatography (ERCP). This report confirms the diagnostic role of ERCP in patients with obstructive jaundice caused by biliary fascioliasis. 相似文献
3.
A Bahrami Y Rassi N Maleki MA Oshaghi M Mohebali MR Yagoobi-Ershadi S Rafizadeh 《亚太热带病杂志(英文版)》2014,4(2):110-114
Objective
To identify the vector(s), the parasite and the species composition of sand flies in the district during May-October 2012.Methods
For reaching our objectives we used polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphism.Results
Two species of Phlebotomus sergenti and Phlebotomus tobbi were the most prevalent among 8 species identified comprising 51.1% and 32.9% respectively. Among the 160 specimens of female sand flies tested by polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphisms, only 1 out of 80 Phlebotomus tobbi (1.25%) were positive to Leishmania infantum parasites.Conclusions
Our finding showed that Phlebotomus tobbi may play as a vector to circulate the parasite of Leishmania infantum among reservoir(s) and human. 相似文献4.
Mahmoud Bahmani Maryam Rasouli Pouya Parsaei Ebrahimkhalil Bahnihabib Koroosh Saki Fereidon Ghotbian 《亚太热带病杂志(英文版)》2013,3(2):155-157
Leech infestation can cause various clinical symptoms in human and animals. There are a few reports about this infestation in the world. In this report, we represented two cases of leech infestation of Limnatis nilotica in domestic kid and ram with anorexia, little respiratory disorders and restlessness in Dehloran city, Ilam province, west of Iran. Based on author''s knowledge, there is no report of leech infestation on ram and kid and the present case is the first report of internal hirudiniasis of ram and kid due to Limnatis niloticain in literature. 相似文献
5.
Mahmoud Bahmani Seyed Ahmad Karamati Morteza Mohamad Hosseini Anari Amir Rahimirad Jafar Asadzadeh Aghakhan Kheiri Ghader Hajiglolizadeh Fereidoun Ghotbian Farzaneh Bahmani 《亚太热带病杂志(英文版)》2014,4(3):210-212
Leeches (phylum: Annelida, class: hirudinea) could infest wide range of livestock such as cow, buffalo, sheep, goat, horse, mule, ass, dog, pig and even human. In November 2013, a 3-year old jackass from Dehloran county, Ilam province, Iran, was infected through his mouth due to drinking spring water. Symptoms including stress, anxiety and tachycardia were seen. After examining oral cavity of jackass, a leech was observed in upper gum. The leech was measured after separation which was three inches in length. The leech was adult which has dark green with orange lines, and it was identified as Limnatis nilotica species. It seems that using spring, subterranean water, pond etc. is the main causes of livestock infestation with leech. Ranchers could be recommended to decontaminate leech waters to prevent further leech infestation cases. 相似文献
6.
Ahad Eshraghian 《World journal of gastroenterology : WJG》2014,20(46):17618-17625
AIM: To investigate the epidemiology of Helicobacter pylori (H. pylori) infection among the healthy asymptomatic population in Iran and countries of the Eastern Mediterranean Region.METHODS: A computerized English language literature search of PubMed, ISI Web of Science, Scopus, and Google Scholar was performed in September 2013. The terms, “Eastern Mediterranean Regional Office (EMRO)” and “Helicobacter pylori”, “H. pylori” and “prevalence” were used as key words in titles and/or abstracts. A complementary literature search was also performed in the following countries: Afghanistan, Bahrain, Djibouti, Egypt, Iran, Iraq, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Pakistan, Palestine, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, The United Arab Emirates, and Yemen.RESULTS: In the electronic search, a total of 308 articles were initially identified. Of these articles, 26 relevant articles were identified and included in the study. There were 10 studies from Iran, 5 studies from the Kingdom of Saudi Arabia, 4 studies from Egypt, 2 from the United Arab Emirates, and one study from Libya, Oman, Tunisia, and Lebanon, respectively. The overall prevalence of H. pylori infection in Iran, irrespective of time and age group, ranged from 30.6% to 82%. The overall prevalence of H. pylori infection, irrespective of time and age group, in other EMRO countries ranged from 22% to 87.6%.CONCLUSION: The prevalence of H. pylori in EMRO countries is still high in the healthy asymptomatic population. Strategies to improve sanitary facilities, educational status, and socioeconomic status should be implemented to minimize H. pylori infection. 相似文献
7.
Kevin J. Liu Ethan Steinberg Alexander Yozzo Ying Song Michael H. Kohn Luay Nakhleh 《Proceedings of the National Academy of Sciences of the United States of America》2015,112(1):196-201
We report on a genome-wide scan for introgression between the house mouse (Mus musculus domesticus) and the Algerian mouse (Mus spretus), using samples from the ranges of sympatry and allopatry in Africa and Europe. Our analysis reveals wide variability in introgression signatures along the genomes, as well as across the samples. We find that fewer than half of the autosomes in each genome harbor all detectable introgression, whereas the X chromosome has none. Further, European mice carry more M. spretus alleles than the sympatric African ones. Using the length distribution and sharing patterns of introgressed genomic tracts across the samples, we infer, first, that at least three distinct hybridization events involving M. spretus have occurred, one of which is ancient, and the other two are recent (one presumably due to warfarin rodenticide selection). Second, several of the inferred introgressed tracts contain genes that are likely to confer adaptive advantage. Third, introgressed tracts might contain driver genes that determine the evolutionary fate of those tracts. Further, functional analysis revealed introgressed genes that are essential to fitness, including the Vkorc1 gene, which is implicated in rodenticide resistance, and olfactory receptor genes. Our findings highlight the extent and role of introgression in nature and call for careful analysis and interpretation of house mouse data in evolutionary and genetic studies.Classical laboratory mouse strains, as well as newly established wild-derived ones, are widely used by geneticists for answering a diverse array of questions (1). Understanding the genome contents and architecture of these strains is important for studies of natural variation and complex traits, as well as evolutionary studies in general (2). Mus spretus, a sister species of Mus musculus, impacts the findings in M. musculus investigations for at least two reasons. First, it was deliberately interbred with laboratory M. musculus strains to introduce genetic variation (3). Second, Mus musculus domesticus is partially sympatric (naturally cooccurring) with M. spretus (Fig. 1).Open in a separate windowFig. 1.Species ranges and samples used in our study. The species range of M. spretus is shown in green (4), and the species range of M. m. domesticus includes the blue regions, the range of M. spretus, and beyond (1). M. m. domesticus and M. spretus samples were obtained from locations marked with red circles and purple diamonds, respectively. The samples originated from within and outside the area of sympatry between the two species. (SI Appendix, Table S1, provides additional details about the samples used in our study.)Recent studies have examined admixture between subspecies of house mice (5–8), but have not studied introgression with M. spretus. In at least one case (5), the introgressive descent of the mouse genome was hidden due to data postprocessing that masked introgressed genomic regions as missing data. In another study reporting whole-genome sequencing of 17 classical laboratory strains (6), M. spretus was used as an outgroup for phylogenetic analysis. The authors were surprised to find that 12.1% of loci failed to place M. spretus as an outgroup to the M. musculus clade. The authors concluded that M. spretus was not a reliable outgroup but did not pursue their observation further. On the other hand, in a 2002 study (9), Orth et al. compiled data on allozyme, microsatellite, and mitochondrial variation in house mice from Spain (sympatry) and nearby countries in western and central Europe. Interestingly, allele sharing between the species was observed in the range of sympatry but not outside in the range of allopatry. The studies demonstrated the possibility of natural hybridization between these two sister species. Further, the study of Song et al. (10) demonstrated a recent adaptive introgression from M. spretus into some M. m. domesticus populations in the wild, involving the vitamin K epoxide reductase subcomponent 1 (Vkorc1) gene, which was later shown to be more widespread in Europe, albeit geographically restricted to parts of southwestern and central Europe (11).Major, unanswered questions arise from these studies. First, is the vicinity around the Vkorc1 gene an isolated case of adaptive introgression in the house mouse genome, or do many other such regions exist? Second, is introgression between M. spretus and M. m. domesticus common outside the range of sympatry? Third, have there been other hybridization events, and, in particular, more ancient ones? Fourth, what role do introgressed genes, and, more generally, genomic regions, play?To investigate these open questions, we used genome-wide variation data from 20 M. m. domesticus samples (wild and wild-derived) from the ranges of sympatry and allopatry, as well as two M. spretus samples. For detecting introgression, we used PhyloNet-HMM (12), a newly developed method for statistical inference of introgression in genomes while accounting for other evolutionary processes, most notably incomplete lineage sorting (ILS).Our analysis provides answers to the questions posed above. First, we find signatures of introgression between M. spretus and each of the M. m. domesticus samples. The amount of introgression varies across the autosomes of each genome, with a few chromosomes harboring all detectable introgression, and most of the chromosomes have none. We detected no introgression on the X chromosome. Further, the amount of introgression varied widely across the samples. Our analyses demonstrate introgression outside the range of sympatry. In fact, our results show more signatures of introgression in the genomes of allopatric samples from Europe than in sympatric samples from Africa. For the third question, we used the length distribution and sharing patterns of introgressed regions across the samples to show support for at least three hybridization events: an ancient hybridization event that predates the colonization of Europe by M. m. domesticus and two more recent events, one of which presumably occurred about 50 y ago and is related to warfarin resistance selection (10). For the fourth question, our functional analysis of the introgressed genes shows enrichment for certain categories, most notably olfaction—an essential trait for the fitness of rodents. Understanding the genomic architecture and evolutionary history of the house mouse has broad implications on various aspects of evolutionary, genetic, and biomedical research endeavors that use this model organism. The PhyloNet-HMM method (12) can be used to detect introgression in other eukaryotic species, further broadening the impact of this work. 相似文献
8.
9.
Plasmodium falciparum resistance to chloroquine (CQ) has been documented in Iran since the early 1980s and has since gradually increased. Iran is therefore reviewing its national drug policy for malaria control. We describe the prevalence of single nucleotide polymorphisms (SNP) associated with quinoline drug resistance in south eastern Iran. Pre-treatment blood from patients with uncomplicated but symptomatic P. falciparum infection was analysed. Polymorphisms at codons 76, 152, 163 and 220 of the pfcrt gene (chloroquine resistance transporter) and at codons 86, 184, 1034, 1042 and 1246 of the pfmdr1 gene (multidrug resistance) were determined by PCR-RFLP and sequencing. In addition, SNPs on a recently described multidrug resistance protein (pfmrp) and a microsatellite (MS-4760) in the pfnhe-1 (sodium hydrogen exchanger) gene associated with quinoline and quinine resistance, respectively, were investigated for the first time in field samples not from Thailand. pfcrt 76T was found in 99% and pfmdr1 86Y in 72% of the samples. pfmrp 191H and 437S associated with decreased quinoline response were found to be absolutely linked at a frequency of 13.6%. The pfnhe-1 MS-4760 one repeat allele associated to quinine response in vitro was also detected. Sequencing of the pfcrt 72-76 haplotype revealed that SVMNT was the most common allele as previously observed in India. This suggests that pfcrt found in the Iranian P. falciparum population may have the same origin as in the P. falciparum populations in India but different from that normally found in south east Asia. In conclusion, the frequencies of quinoline resistance associated gene polymorphisms in this region suggest a population that has been significantly selected for by the long use of CQ. 相似文献
10.
Leila Shokrzadeh Fereshteh Jafari Hossein Dabiri Kaveh Baghaei Homayoun Zojaji Amir H. Alizadeh Mohammad Mehdi Aslani Mohammad R. Zali 《Saudi Journal Of Gastroenterology》2011,17(4):261-264
Background/Aim:
Helicobacter pylori is an important pathogen for gastroduodenal diseases. Infection with H. pylori can be limited by regimens of multiple antimicrobial agents. However, antibiotic resistance is a leading cause of treatment failure. The aim of this study has been to determine the resistance patterns of H. pylori strains isolated from gastric biopsies of patients with dyspepsia by agar dilution method, in Tehran, IranPatients and Methods:
H. pylori isolates from patients with gastrointestinal diseases were evaluated for susceptibility testing by agar dilution method. Susceptibility testing was performed to commonly used antibiotics including clarithromycin, tetracycline, amoxicillin, metronidazole and ciprofloxacin.Results:
Among 92 patients with dyspepsia, H. pylori strains were isolated from 42 patients. Seventeen (40.5%) of the isolates were resistant to metronidazole (MICs ≥ 8 μg/l), whereas one isolate (2.4%) was resistant to amoxicillin (MICs ≤ 0. 5 μg/ml) and ciprofloxacin (MICs ≤ 1μg/ml). The resistance rates to other antibiotics in H. pylori isolates are recorded as follows: clarithromycin 6 (14.3 %), tetracycline 2 (4.8%). In 5 of 42 resistant cases, combined resistance was found.Conclusions:
These data suggest that metronidazole should be used among Iranian patients in first-line therapy with caution, and ciprofloxacin in association with amoxicillin and a proton pump inhibitor is more recommended. 相似文献11.
Tunga penetrans is an ectoparasite causing considerable morbidity in endemic communities. Recently, endobacteria of the genus Wolbachia were identified also in T. penetrans. Since Wolbachia were suggested as targets for intervention of insect pests and human filariasis, sand fleas were collected from infested humans, dogs and rats in a hyperendemic area in northeastern Brazil, and screened for Wolbachia infections. Twenty-one adult fleas and four batches of flea eggs were examined by PCR using primers targeting the 16S rDNA, the DNA coding for FtsZ cell-cycle protein or a Wolbachia surface protein (WSP-1). Wolbachia were detected in all examined samples from eggs, free-living male and female fleas and from neosomic female fleas. No Wolbachia DNA was detected in two samples containing flea faeces. In addition, Wolbachia were labelled by immunohistology in the ovaries of 37 female fleas using antisera raised against WSP-1 of Wolbachia the filarial parasite Dirofilaria immitis. In the vicinity of the embedded fleas containing the Wolbachia, infiltrations of neutrophils and macrophages were observed. This study showed that Wolbachia endobacteria are abundant in T. penetrans and that all examined fleas were infected by these endobacteria. Our findings may have important implications for the future development of control strategies for human tungiasis. 相似文献
12.
Smears of suspected patients infected with zoonotic cutaneous leishmaniasis (ZCL) were stained and examined under a light microscopic observation. DNA of parasites within human ulcers was extracted directly from their smears. Nested PCR was used to amplify a fragment containing the internal transcribed spacers of the ribosomal RNA genes (ITS-rDNA) of Lesihmania parasites in human from Turkemen Sahara located in the northeastern part of Iran. Based on RFLP method by digesting BsuRI restriction enzyme and more precisely sequencing of DNA ITS-rDNA was shown to be species-specific. The infection rates of Leishmania parasites were high with 154 (93.9%) infections out of 164 suspected patients using microscopic observations. Only from 128 suspected patients out of 164, ITS-rDNA fragments were amplified and 125 samples had enough DNA to digest BsuRI restriction enzyme and do DNA sequencing. The Nested PCR assays detected not only Leishmania major but also Leishmania turanica for the first time, another parasite of the great gerbil in human. The density of L. major was high but the diversity was low with only 2 haplotypes. The overall ratio of L. major (123 infections) to L. turanica (2 infections) was significantly higher (Chi-squared test: p < 0.05). Infections of L. turanica are not reported only and/or not known to cause human disease. Our analytical framework conveys a clear understanding of both L. major and L. turanica which can only be approved as causative agents of ZCL by more extensive sampling and followed by standardized molecular diagnosis. 相似文献
13.
Kelly L. Warfield Emily Plummer Dominic S. Alonzi Gary W. Wolfe Aruna Sampath Tam Nguyen Terry D. Butters Sven G. Enterlein Eric J. Stavale Sujan Shresta Urban Ramstedt 《Viruses》2015,7(5):2404-2427
Iminosugars are capable of targeting the life cycles of multiple viruses by blocking host endoplasmic reticulum α-glucosidase enzymes that are required for competent replication of a variety of enveloped, glycosylated viruses. Iminosugars as a class are approved for use in humans with diseases such as diabetes and Gaucher’s disease, providing evidence for safety of this class of compounds. The in vitro antiviral activity of iminosugars has been described in several publications with a subset of these demonstrating in vivo activity against flaviviruses, herpesviruses, retroviruses and filoviruses. Although there is compelling non-clinical in vivo evidence of antiviral efficacy, the efficacy of iminosugars as antivirals has yet to be demonstrated in humans. In the current study, we report a novel iminosugar, UV-12, which has efficacy against dengue and influenza in mouse models. UV-12 exhibits drug-like properties including oral bioavailability and good safety profile in mice and guinea pigs. UV-12 is an example of an iminosugar with activity against multiple virus families that should be investigated in further safety and efficacy studies and demonstrates potential value of this drug class as antiviral therapeutics. 相似文献
14.
Glynis L. Kolling Martin Wu Cirle A. Warren Evelyn Durmaz Todd R. Klaenhammer Richard L. Guerrant 《Gut microbes》2012,3(6):523-529
Antibiotic treatment to treat specific infections has the potential to effectively target the offending microbe as well as other microbes that colonize sites within a host. Antibiotic-associated diarrhea (AAD) is a classic example resulting from disruption of host microbial communities; 20% of patients with AAD are likely to become colonized with Clostridium difficile. Restoration of a “normal” microbial community within the host using probiotic bacteria is one approach to circumvent AAD and C. difficile infection. The goals of this study were to assess the interactions between Streptococcus thermophilus, a potential probiotic organism and C. difficile using both in vitro and in vivo systems. Exposure of C. difficile to filtered supernatants from S. thermophilus showed a dose-dependent, bactericidal effect due to lactic acid. Additional studies show that levels of lactic acid (10 mM) that did not inhibit bacterial growth had the potential to decrease tcdA expression and TcdA release into the extracellular milieu. In vivo, treatment with viable S. thermophilus significantly increased luminal levels of lactate in the cecum compared with UV-irradiated S. thermophilus. In the context of infection with C. difficile, mice treated with viable S. thermophilus exhibited 46% less weight loss compared with untreated controls; moreover, less pathology, diarrhea, and lower detectable toxin levels in cecal contents were evident more often in S. thermophillus treated mice. A significant, inverse correlation (Spearman r = -0.942, p = 0.017) between the levels of luminal lactate and abundance of C. difficile were noted suggesting that lactate produced by S. thermophilus is a factor impacting the progression of C. difficile infection in the murine system. 相似文献
15.
Nuttanan Hongsrichan Rucksak Rucksaken Yaovalux Chamgramol Porntip Pinlaor Anchalee Techasen Puangrat Yongvanit Narong Khuntikeo Chawalit Pairojkul Somchai Pinlaorr 《World journal of gastroenterology : WJG》2013,19(16):2456-2465
AIM: To evaluate a new immunohistological marker, annexin A1 (ANXA1), in cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC). METHODS: Expression of ANXA1 protein was investigated in liver tissues from patients with CCA and HCC by immunohistochemistry. Its expression on differences stages of tumor development was investigated in hamster CCA tissues induced by Opisthorchis viverrini and N -nitrosodimethylamine. Moreover, mRNA expression of ANXA1 was assessed in CCA cell lines by quantitative real-time polymerase chain reaction and silencing of ANXA1 gene expression using small interfering RNA. RESULTS: In human CCA tissue arrays, immunohistochemical analysis revealed that the positive expression of ANXA1 was 94.1% (64/68 cases) consisting of a high expression (66.2%, 45/68 cases) and a low expression (33.8%, 23/68 cases). However, expression of ANXA1 protein was negative in all histologic patterns for HCC (46/46 cases) and healthy individuals (6/6 cases). In hamster with opisthorchiasis-associated CCA, the expression of ANXA1 was observed in the cytoplasm of inflammatory cells, bile duct epithelia and tumor cells. Grading scores of ANXA1 expression were significantly increased with tumor progression. In addition, mRNA expression of ANXA1 significantly increased in all of the various CCA cell lines tested compared to an immortalized human cholangiocyte cell line (MMNK1). Suppressing the ANXA1 gene significantly reduced the matrix metalloproteinase (MMP) 2 and MMP9, and transforming growth factor-β genes, but increased nuclear factor-kB gene expression. CONCLUSION: ANXA1 is highly expressed in CCA, but low in HCC, suggesting it may serve as a new immunohistochemical marker of CCA. ANXA1 may play a role in opisthorchiasis-associated cholangiocarcinogenesis. 相似文献
16.
Smith ME Cimica V Chinni S Jana S Koba W Yang Z Fine E Zagzag D Montagna C Kalpana GV 《Proceedings of the National Academy of Sciences of the United States of America》2011,108(1):319-324
Rhabdoid tumors (RTs) are rare, highly aggressive pediatric malignancies with poor prognosis and with no standard or effective treatment strategies. RTs are characterized by biallelic inactivation of the INI1 tumor suppressor gene. INI1 directly represses CCND1 and activates cyclin-dependent kinase (cdk) inhibitors p16(Ink4a) and p21(CIP). RTs are exquisitely dependent on cyclin D1 for genesis and survival. To facilitate translation of unique therapeutic strategies, we have used genetically engineered, Ini1(+/-) mice for therapeutic testing. We found that PET can be used to noninvasively and accurately detect primary tumors in Ini1(+/-) mice. In a PET-guided longitudinal study, we found that treating Ini1(+/-) mice bearing primary tumors with the pan-cdk inhibitor flavopiridol resulted in complete and stable regression of some tumors. Other tumors showed resistance to flavopiridol, and one of the resistant tumors overexpressed cyclin D1, more than flavopiridol-sensitive cells. The concentration of flavopiridol used was not sufficient to down-modulate the high level of cyclin D1 and failed to induce cell death in the resistant cells. Furthermore, FISH and PCR analyses indicated that there is aneuploidy and increased CCND1 copy number in resistant cells. These studies indicate that resistance to flavopiridol may be correlated to elevated cyclin D1 levels. Our studies also indicate that Ini1(+/-) mice are valuable tools for testing unique therapeutic strategies and for understanding mechanisms of drug resistance in tumors that arise owing to loss of Ini1, which is essential for developing effective treatment strategies against these aggressive tumors. 相似文献
17.
Claycombe K King LE Fraker PJ 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(6):2017-2021
Although leptin is known for its regulation of food intake, it has many emerging roles in immune function. To better define the role of leptin in hematopoietic processes, a leptin-deficient obese mouse (ob/ob) and C57BL/6 lean wild-type controls were compared. Despite their large size and consumption of substantial amounts of nutrients, the ob/ob mice had only 60% as many nucleated cells in their marrow as controls. The greatest impact of leptin deficiency was on the B cell compartment that had 70% fewer cells, reducing the absolute number of pre-B and immature B cells to 21% and 12% of normal, respectively, and indicating a significant reduction in lymphopoiesis in ob/ob mice. Whereas the proportion of myeloids remained nearly normal in the obese mice, they also exhibited a reduction of 40% and 25%, respectively, in absolute numbers of granulocytes and monocytes. Seven days of provision of recombinant leptin promoted substantial lymphopoiesis, increasing the numbers of B cells in the marrow of the obese mice twofold, while doubling and tripling, respectively, the numbers of pre-B and immature B cells. Twelve days of supplementation brought these subpopulations to near-normal proportions. Leptin treatment also facilitated myelopoiesis such that the marrow of the obese mice contained normal numbers of monocytes and granulocytes after 7 days. Taken together, the data support an important role for leptin in sustaining lymphopoiesis and myelopoiesis. 相似文献
18.
Ferrer M Golyshina OV Beloqui A Böttger LH Andreu JM Polaina J De Lacey AL Trautwein AX Timmis KN Golyshin PN 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(26):8878-8883
We describe here an extraordinary purple-colored DNA ligase, LigFa, from the acidophilic ferrous iron-oxidizing archaeon Ferroplasma acidiphilum, a di-ferric enzyme with an extremely low pH activity optimum. Unlike any other DNA ligase studied to date, LigFa contains two Fe(3+)-tyrosinate centers and lacks any requirement for either Mg(2+) or K(+) for activity. DNA ligases from closest phylogenetic and ecophysiological relatives have normal pH optima (6.0-7.5), lack iron, and require Mg(2+)/K(+) for activity. Ferric iron retention is pH-dependent, with release resulting in partial protein unfolding and loss of activity. Reduction of the Fe(3+) to Fe(2+) results in an 80% decrease in DNA substrate binding and an increase in the pH activity optimum to 5.0. DNA binding induces significant conformational change around the iron site(s), suggesting that the ferric irons of LigFa act both as structure organizing and stabilizing elements and as Lewis acids facilitating DNA binding at low pH. 相似文献
19.
Vatandoost H Oshaghi MA Abaie MR Shahi M Yaaghoobi F Baghaii M Hanafi-Bojd AA Zamani G Townson H 《Acta tropica》2006,97(2):196-203
Anopheles stephensi Liston is an important malaria vector in Hormozgan province, where it is the most prevalent anopheline mosquito. It shows two annual activity peaks, one in spring and another in the autumn. In mountainous areas the second peak starts earlier than in coastal regions. Adults are endophilic and endophagic, but in the hot season when people sleep outside buildings they frequently bite outdoors. Larvae are found in a wide-range of habitats, both natural and man-made. All three biological forms of the species, occur in the province, i.e. An. stephensi stephensi (type form), An. stephensi mysorensis, and the intermediate form. An. stephensi mysorensis is found only in rural-mountainous areas, whereas the type and intermediate forms occur in urban-coastal regions and the rural plains, with the type form predominant. The presence of the type form in urban areas and mysorensis in rural areas is consistent with the available epidemiological data for malaria in the region and with the finding in India that the type form is an efficient malaria vector inhabiting urban areas whereas mysorensis is rural and has a lower vectorial capacity. Insecticide susceptibility tests on field collected adult mysorensis and adults from laboratory strains of the type and intermediate forms were carried out according to WHO standard methods. These showed that all three forms are susceptible to bendiocarb, propoxur, malathion, fenitrothion, deltamethrin, permethrin, cyfluthrin, and lambdacyhalothrin, but are resistant to DDT and show low level of tolerance to dieldrin. Examination of the larvicidal activity of malathion, fenitrothion, temephos and chlorpyrifos at diagnostic doses showed that these stephensi forms are susceptible to all larvicides except fenitrothion. Irritability tests to pyrethroid insecticides showed high levels of irritability to permethrin and lambdacyhalothrin, but low irritability to cyfluthrin and deltamethrin. The importance of these findings for the epidemiology and control of malaria in the region are discussed. 相似文献
20.
Antonio Bernardo Carvalho Beatriz Vicoso Claudia A. M. Russo Bonnielin Swenor Andrew G. Clark 《Proceedings of the National Academy of Sciences of the United States of America》2015,112(40):12450-12455
Contrary to the pattern seen in mammalian sex chromosomes, where most Y-linked genes have X-linked homologs, the Drosophila X and Y chromosomes appear to be unrelated. Most of the Y-linked genes have autosomal paralogs, so autosome-to-Y transposition must be the main source of Drosophila Y-linked genes. Here we show how these genes were acquired. We found a previously unidentified gene (flagrante delicto Y, FDY) that originated from a recent duplication of the autosomal gene vig2 to the Y chromosome of Drosophila melanogaster. Four contiguous genes were duplicated along with vig2, but they became pseudogenes through the accumulation of deletions and transposable element insertions, whereas FDY remained functional, acquired testis-specific expression, and now accounts for ∼20% of the vig2-like mRNA in testis. FDY is absent in the closest relatives of D. melanogaster, and DNA sequence divergence indicates that the duplication to the Y chromosome occurred ∼2 million years ago. Thus, FDY provides a snapshot of the early stages of the establishment of a Y-linked gene and demonstrates how the Drosophila Y has been accumulating autosomal genes.The mammalian Y chromosome has the lowest gene density of any chromosome, and most of its genes have a homolog on the X. This pattern is consistent with the mammalian sex chromosomes having originated from an ordinary pair of chromosomes, followed by massive gene loss from the Y (1–4). In contrast, the closest homologs of all Drosophila melanogaster Y-linked protein-encoding genes are autosomal, strongly suggesting that its Y chromosome has been acquiring genes from the autosomes (5–7). Indeed, gene gains, and not gene losses, have played the major role in shaping the gene content of the Drosophila Y, at least in the last ∼63 million years (My) (8, 9). Hence, the Drosophila Y chromosome seems to be evolving noncanonically (10) and is an ideal model to investigate the dynamics of gene gain on a nonrecombining Y chromosome.The Drosophila Y chromosome has long been known to contain genes essential for male fertility (11, 12). Due to its heterochromatic state, progress in the molecular identification of the Y-linked single-copy genes has been slow. male fertility factor kl5 (kl-5), the first single-copy gene identified, was found serendipitously; it encodes a motor protein (dynein heavy chain) required for flagellar beating (13). More recently, a combination of computational and experimental methods identified 11 single-copy Y-linked genes among the unmapped sequence scaffolds produced by the Drosophila Genome Project (5–7). These genes have two striking features: (i) their closest paralogs are autosomal and not X linked, and (ii) they have male-specific functions, such as the beating of sperm flagella reported for the kl-5 gene (14). The most likely explanation for this pattern is that Y-linked genes were acquired from the autosomes and have been retained because they confer a specific fitness advantage to their carriers. An autosomal origin has previously been reported for a few Y-linked genes in humans and a repetitive gene on the Drosophila Y (4, 15). However, unequivocal evidence of the autosomal origin of Drosophila Y-linked genes, and of the specific mechanism that originated them, is lacking due to their antiquity. The 11 known single-copy genes (kl-2, kl-3, kl-5, ARY, WDY, PRY, Pp1-Y1, Pp1-Y2, Ppr-Y, ORY, and CCY) represent ancient duplications, with amino acid identities to the putative ancestors ranging from 30% to 74%, and poor (if any) alignment at the nucleotide level. Most of them have introns in conserved positions compared with their autosomal paralogs, ruling out retrotransposition and suggesting DNA-based duplication as the mechanism. The original size of these putative duplications is unknown, because the similarity between autosomal and Y-linked regions is restricted to one gene in each case. Flanking sequences and contiguous genes either were not duplicated or were subsequently mutated and deleted beyond recognition.Here we describe flagrante delicto Y (FDY), a single copy Y-linked gene present only in D. melanogaster, and which is 98% identical at the nucleotide level to the autosomal gene vig2. Because its origin is very recent (it occurred after the split between D. melanogaster and Drosophila simulans, ∼4 Mya), it was possible to demonstrate that FDY arose from a DNA-based duplication of chromosome 3R to the Y: the duplicated segment spans 11 kb of autosomal sequence and includes five contiguous genes (vig2, Mocs2, CG42503, Clbn, and Bili); the last four genes became pseudogenes by rapid accumulation of deletions, point mutations, and transposable element insertions or by lack of expression. Thus, FDY unequivocally demonstrates that the Drosophila Y has acquired genes from autosomes. Several Y-linked genes such as kl-2, kl-3, and PRY are shared by distant Drosophila species that diverged ∼60 Mya, implying ancient acquisitions. FDY dates the more recent acquisition to ∼2 My, and hence strongly suggests that Drosophila Y has been continuously acquiring autosomal genes. 相似文献