Aerobic bacteriological analysis of bronchoalveolar lavage fluid in patients with pulmonary infection: a tertiary care hospital study

Background: Respiratory tract infection are an important cause of mortality and morbidity worldwide. The prevalent bacterial agents and their antimicrobial resistance patterns differs, both geographically and over time. Bronchoalveolar lavage has improved sensitivity and specificity of diagnostic techniques in diagnosis of pulmonary infections. The present study aimed to determine the current aerobic bacterial isolates and their sensitivity pattern obtained from the bronchoalveolar lavage (BAL) fluid of patients with pulmonary infection.Methods: BAL samples received from the patients of suspected respiratory tract infections over a period of one year, from June 2018 to May 2019 were processed by standard methods for isolation and identification. The antimicrobial susceptibility was done by the Kirby-Bauer disc diffusion method as per the CLSI guidelines.Results: Out of 322 BAL samples, 84 (26.08%) were found to be culture positive for bacterial isolates. Of those, 44 samples (52.38%) from among males and 40 samples (47.61%) from among females were culture positive .The predominant organism isolated was Pseudomonas aeruginosa 46 (54.76%) followed by Acinetobacter baumanii 13 (15.47%), Escherichia coli 10 (11.90%), Klebsiella pnuemoniae 6 (7.14%) Enterobacter sp 3 (3.57%), Staphylococcus aureus 3 (3.57%), Enterococcus sp 2 (2.38%) and Sphingomonas sp 1 (1.19%). The Gram-negative organisms showed maximum sensitivity to colistin (100%) while as vancomycin and linezolid were the most effective drugs against Gram positive organisms.Conclusions: Bronchoalveolar lavage has improved sensitivity and specificity in diagnosis of pulmonary infections. It is important to have an updated local antibiogram for each hospital and regular surveillance and monitoring of antibiotic resistance and the changing patterns of the bacterial pathogens is a must for better patient management

The Essential Role of Drosophila HIRA for De Novo Assembly of Paternal Chromatin at Fertilization

In many animal species, the sperm DNA is packaged with male germ line–specific chromosomal proteins, including protamines. At fertilization, these non-histone proteins are removed from the decondensing sperm nucleus and replaced with maternally provided histones to form the DNA replication competent male pronucleus. By studying a point mutant allele of the Drosophila Hira gene, we previously showed that HIRA, a conserved replication-independent chromatin assembly factor, was essential for the assembly of paternal chromatin at fertilization. HIRA permits the specific assembly of nucleosomes containing the histone H3.3 variant on the decondensing male pronucleus. We report here the analysis of a new mutant allele of Drosophila Hira that was generated by homologous recombination. Surprisingly, phenotypic analysis of this loss of function allele revealed that the only essential function of HIRA is the assembly of paternal chromatin during male pronucleus formation. This HIRA-dependent assembly of H3.3 nucleosomes on paternal DNA does not require the histone chaperone ASF1. Moreover, analysis of this mutant established that protamines are correctly removed at fertilization in the absence of HIRA, thus demonstrating that protamine removal and histone deposition are two functionally distinct processes. Finally, we showed that H3.3 deposition is apparently not affected in Hira mutant embryos and adults, suggesting that different chromatin assembly machineries could deposit this histone variant

MTHFR gene C677T and A1298C polymorphisms and homocysteine levels in primary open angle and primary closed angle glaucoma

Contains fulltext : 79920.pdf (publisher's version ) (Open Access)PURPOSE: To investigate the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C genotypes and plasma concentrations of total homocysteine (tHcy) in Pakistani patients with primary open angle glaucoma (POAG) and primary closed angle glaucoma (PCAG). METHODS: This was a prospective case-control study. A total of 295 patients (173 POAG, 122 PCAG) and 143 age- and sex-matched controls were subdivided into two ethnic groups, Punjabis (Punjab province, central Pakistan) and Pathans (North-West Frontier Province, northern Pakistan). Genotypes of the MTHFR C677T and A1298C polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An enzyme-linked immunosorbent assay was used to determine the total serum homocysteine (tHcy) levels. Associations were determined by logistic regression analysis. RESULTS: Frequency distributions of genotypes and combined genotypes as well as homocysteine levels were obtained. The overall distribution of the C677T genotype was found to be significantly associated with PCAG (CC 69%, CT 21%, TT 10%; p=0.001, chi(2)=12.6), but not with POAG (CC 71%, CT 28%, TT 1%; p=0.98, chi(2)=0.02) as compared to the controls (CC 71%, CT 29%, TT 1%). The Pathan cohorts revealed no association with the disease; however, the Punjabis demonstrated a significant association with PCAG (CC 75%, CT 11%, TT 13%; p<0.001, chi(2)=17.2). PCAG in the Punjabi subjects was also significantly associated with the A1298C polymorphism (AA 43%, AC 54%, CC 3%; p<0.001, chi(2)=33.9) as compared to the controls. Combined genotype data showed no association with POAG; however, a significant association with all combined genotypes was observed in the overall PCAG subjects (p<0.05, chi(2)=20.1). This difference was particularly apparent in the TTAA and TTAC combinations that were completely absent in the control groups (p<0.05. chi(2)=49.6). Mean serum tHcy levels were found to be significantly increased in the POAG (15.2+/-1.28 micromol/l, p<0.001) and PCAG (20.8+/-4.8 micromol/l) groups as compared to the controls (10.0+/-0.97 micromol/l). The tHcy levels in the TT and AC genotype were significantly elevated in the PCAG group (67+/-12.39 micromol/l, p<0.001; 23+/-5.94 micromol/l, p=0.027) as compared to the controls. CONCLUSION: The TT and AC genotypes of MTHFR C677T and A1298C polymorphisms and the combined genotype TTAC were associated with PCAG in Punjabi subjects of Pakistani origin and correlated with the high serum tHcy levels seen in these patients

The association of glutathione S-transferase GSTT1 and GSTM1 gene polymorphism with pseudoexfoliative glaucoma in a Pakistani population

Contains fulltext : 88996.pdf (publisher's version ) (Open Access)PURPOSE: The aim of the present study was to investigate the association of glutathione S-transferase GSTT1 and GSTM1 genotypes with pseudoexfoliative glaucoma (PEXG) in a group of Pakistani patients. METHODS: Multiplex polymerase chain reaction was used to study the GSTT1 and GSTM1 polymorphisms in 165 PEXG patients and 162 unaffected controls. RESULTS: In the current study we describe a significant gender-specific association of GSTT1 and GSTM1 null genotypes with PEXG. The three null genotype combinations (i.e., T1M0, T0M1, and T0M0) were found at significantly higher frequencies in the PEXG patients as compared to the controls (chi(2)=21.82, p0.05). CONCLUSIONS: The results suggest that there is a significant involvement of the GSTT1 and GSTM1 polymorphisms in female Pakistani patients having PEXG, which suggests a possible gender-specific impairment of detoxification in this group

Drosophila SETDB1 Is Required for Chromosome 4 Silencing

Histone H3 lysine 9 (H3K9) methylation is associated with gene repression and heterochromatin formation. In Drosophila, SU(VAR)3–9 is responsible for H3K9 methylation mainly at pericentric heterochromatin. However, the histone methyltransferases responsible for H3K9 methylation at euchromatic sites, telomeres, and at the peculiar Chromosome 4 have not yet been identified. Here, we show that DmSETDB1 is involved in nonpericentric H3K9 methylation. Analysis of two DmSetdb1 alleles generated by homologous recombination, a deletion, and an allele where the 3HA tag is fused to the endogenous DmSetdb1, reveals that this gene is essential for fly viability and that DmSETDB1 localizes mainly at Chromosome 4. It also shows that DmSETDB1 is responsible for some of the H3K9 mono- and dimethyl marks in euchromatin and for H3K9 dimethylation on Chromosome 4. Moreover, DmSETDB1 is required for variegated repression of transgenes inserted on Chromosome 4. This study defines DmSETDB1 as a H3K9 methyltransferase that specifically targets euchromatin and the autosomal Chromosome 4 and shows that it is an essential factor for Chromosome 4 silencing

Telomeric Trans-Silencing: An Epigenetic Repression Combining RNA Silencing and Heterochromatin Formation

The study of P-element repression in Drosophila melanogaster led to the discovery of the telomeric Trans-Silencing Effect (TSE), a repression mechanism by which a transposon or a transgene inserted in subtelomeric heterochromatin (Telomeric Associated Sequence or TAS) has the capacity to repress in trans in the female germline, a homologous transposon, or transgene located in euchromatin. TSE shows variegation among egg chambers in ovaries when silencing is incomplete. Here, we report that TSE displays an epigenetic transmission through meiosis, which involves an extrachromosomal maternally transmitted factor. We show that this silencing is highly sensitive to mutations affecting both heterochromatin formation (Su(var)205 encoding Heterochromatin Protein 1 and Su(var)3–7) and the repeat-associated small interfering RNA (or rasiRNA) silencing pathway (aubergine, homeless, armitage, and piwi). In contrast, TSE is not sensitive to mutations affecting r2d2, which is involved in the small interfering RNA (or siRNA) silencing pathway, nor is it sensitive to a mutation in loquacious, which is involved in the micro RNA (or miRNA) silencing pathway. These results, taken together with the recent discovery of TAS homologous small RNAs associated to PIWI proteins, support the proposition that TSE involves a repeat-associated small interfering RNA pathway linked to heterochromatin formation, which was co-opted by the P element to establish repression of its own transposition after its recent invasion of the D. melanogaster genome. Therefore, the study of TSE provides insight into the genetic properties of a germline-specific small RNA silencing pathway

Role of Lysyl oxidase-like 1 gene polymorphisms in Pakistani patients with pseudoexfoliative glaucoma

Contains fulltext : 109429.pdf (publisher's version ) (Open Access)PURPOSE: Single nucleotide polymorphisms (SNPs) rs1048661 (p.R141L) and rs3825942 (p.G153D) in the lysyl oxidase-like 1 (LOXL1) gene have been previously reported to be associated with pseudoexfoliation glaucoma (PEXG) in various Asian and European populations, but these SNPs have not yet been studied in the Pakistani population. Therefore the aim of the present study was to investigate the association of these two coding LOXL1 SNPs in Pakistani PEXG patients. METHODS: One hundred twenty-eight Pakistani patients diagnosed with PEXG and 180 healthy controls were recruited for the study. Genomic DNA was extracted and both SNPs were genotyped by direct sequencing. Association of genotype and allele frequencies with PEXG were analyzed using the Chi-square (chi(2)) test. RESULTS: Genotype and allele frequencies of both rs1048661 and rs3825942 were found to be significantly associated with PEXG. The GG genotypes of both LOXL1 SNPs were associated with an increased risk of developing PEXG. In addition the G alleles of rs1048661 and rs3825942 confer an increased risk for PEXG with an odds ratio (OR) of 2.98 (95% CI 1.94-4.57) and OR 6.83 (95% CI 2.94-16.67), respectively. CONCLUSIONS: A significant association was found for the G allele of rs1048661 and rs3825942 in PEXG patients of Pakistani origin

Association of tumor necrosis factor alpha gene polymorphism G-308A with pseudoexfoliative glaucoma in the Pakistani population

Contains fulltext : 80274.pdf (publisher's version ) (Open Access)PURPOSE: The purpose of the present study was to determine the role of the tumor necrosis factor alpha (TNF-alpha) gene polymorphism G-308A and total serum immunoglobulin E (TsIgE) levels in the onset of pseudoexfoliation glaucoma (PEXG) in Pakistani patients. METHODS: The TNF-alpha polymorphism G-308A was analyzed in 122 patients with PEXG and 126 healthy unrelated controls by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). TsIgE levels were determined by solid-phase enzyme-linked immunosorbent assay (ELISA). RESULTS: The AA and GA genotypes were strongly associated with PEXG (p<0.001), with an odds ratio (OR) of 0.07 (95% confidence interval [CI]=0.02-0.27) and 0.24 (95% CI=0.12-0.51), respectively, while the GG genotype was found at a higher frequency in controls as compared to patients (p<0.001) OR=8.95 (95% CI=4.55-17.81). No significant difference was found in TsIgE levels of both patients and controls (p=0.86). CONCLUSION: The present study concludes that the TNF-alpha polymorphism G-308A is strongly associated with PEXG. To our knowledge this is the first study in southeast Asia which demonstrates a strong association of a TNF-alpha polymorphism with PEXG

Plasticity of Fission Yeast CENP-A Chromatin Driven by Relative Levels of Histone H3 and H4

The histone H3 variant CENP-A assembles into chromatin exclusively at centromeres. The process of CENP-A chromatin assembly is epigenetically regulated. Fission yeast centromeres are composed of a central kinetochore domain on which CENP-A chromatin is assembled, and this is flanked by heterochromatin. Marker genes are silenced when placed within kinetochore or heterochromatin domains. It is not known if fission yeast CENP-ACnp1 chromatin is confined to specific sequences or whether histone H3 is actively excluded. Here, we show that fission yeast CENP-ACnp1 can assemble on noncentromeric DNA when it is inserted within the central kinetochore domain, suggesting that in fission yeast CENP-ACnp1 chromatin assembly is driven by the context of a sequence rather than the underlying DNA sequence itself. Silencing in the central domain is correlated with the amount of CENP-ACnp1 associated with the marker gene and is also affected by the relative level of histone H3. Our analyses indicate that kinetochore integrity is dependent on maintaining the normal ratio of H3 and H4. Excess H3 competes with CENP-ACnp1 for assembly into central domain chromatin, resulting in less CENP-ACnp1 and other kinetochore proteins at centromeres causing defective kinetochore function, which is manifest as aberrant mitotic chromosome segregation. Alterations in the levels of H3 relative to H4 and CENP-ACnp1 influence the extent of DNA at centromeres that is packaged in CENP-ACnp1 chromatin and the composition of this chromatin. Thus, CENP-ACnp1 chromatin assembly in fission yeast exhibits plasticity with respect to the underlying sequences and is sensitive to the levels of CENP-ACnp1 and other core histones