The border sequence of the balhimycin biosynthesis gene cluster from Amycolatopsis balhimycina contains bbr, encoding a StrR-like pathway-specific regulator

Balhimycin, produced by the actinomycete Amycolatopsis balhimycina DSM5908, is a glycopeptide antibiotic highly similar to vancomycin, the antibiotic of 'last resort' used for the treatment of resistant Gram-positive pathogenic bacteria. Partial sequence of the balhimycin biosynthesis gene cluster was previously reported. In this work, cosmids which overlap the region of the characterized gene cluster were isolated and sequenced. At the 'left' end of the cluster, genes were identified which are involved in balhimycin biosynthesis, transport, resistance and regulation. The 'right' end border is defined by a putative 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (dahp) gene. The proximate gene is similar to a type I polyketide synthase gene of the rifamycin producer Amycolatopsis mediterranei indicating that another biosynthesis gene cluster might be located directly next to the balhimycin gene cluster. The newly identified StrR-like pathway-specific regulator, Bbr, was characterized to be a DNA-binding protein and may have a role in balhimycin biosynthesis. Purified N-terminally His-tagged Bbr shows specific DNA-binding to five promoter regions within the gene cluster. By in silico analysis and by comparison of the DNA sequences binding Bbr, conserved inverted repeat sequences for the Bbr-binding site are proposed. The putative Bbr consensus sequence differs from that published for StrR.     

Synthesis and characterization of propyl O-β-d-galactopyranosyl-(1→4)-O-β-d-galactopyranosyl-(1→4)-α-d-galactopyranoside

Allyl 4-O-(4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-β-d-galactopyranosyl)-2-O-benzoyl-3,6-di-O-benzyl-α-d- galactopyranoside was O-deallylated to give the 1-hydroxy derivative, and this was converted into the corresponding 1-O-(N-phenylcarbamoyl) derivative, treatment of which with dry HCl produced the α-d-galactopyranosyl chloride. This was converted into the corresponding 2,2,2-trifluoroethanesulfonate, which was coupled to allyl 2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranoside, to give crystalline allyl 4-O-[4-O-(4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-β-d-galactopyranosyl)-2-O-benzoyl-3,6-di- O-benzyl-β-d-galactopyranosyl]-2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranoside (15) in 85% yield, no trace of the α anomer being found. The trisaccharide derivative 15 was de-esterified with 2% KCN in 95% ethanol, and the product O-debenzylated with H₂-Pd, to give the unprotected trisaccharide. Alternative sequences are discussed.     

Future climate conditions accelerate wheat straw decomposition alongside altered microbial community composition,assembly patterns,and interaction networks

Although microbial decomposition of plant litter plays a crucial role in nutrient cycling and soil fertility, we know less about likely links of specific microbial traits and decomposition, especially in relation to climate change. We study here wheat straw decomposition under ambient and manipulated conditions simulating a future climate scenario (next 80 years) in agroecosystems, including decay rates, macronutrient dynamics, enzyme activity, and microbial communities. We show that future climate will accelerate straw decay rates only during the early phase of the decomposition process. Additionally, the projected climate change will increase the relative abundance of saprotrophic fungi in decomposing wheat straw. Moreover, the impact of future climate on microbial community assembly and molecular ecological networks of both bacteria and fungi will strongly depend on the decomposition phase. During the early phase of straw decomposition, stochastic processes dominated microbial assembly under ambient climate conditions, whereas deterministic processes highly dominated bacterial and fungal communities under simulated future climate conditions. In the later decomposition phase, similar assembly processes shaped the microbial communities under both climate scenarios. Furthermore, over the early phases of decomposition, simulated future climate enhanced the complexity of microbial interaction networks. We concluded that the impact of future climate on straw decay rate and associated microbial traits like assembly processes and inter-community interactions is restricted to the early phase of decomposition.Subject terms: Soil microbiology, Environmental sciences     

Isolation and characterization of human heparin.

Heparin was isolated from an unusually large human hemangioma that contained an elevated level of mast cells. Purification of multimilligram quantities of heparin from this tissue sample permitted a thorough examination of its structure and activity. Characterization of this human heparin included the following: one-dimensional and two-dimensional 1H-nuclear magnetic resonance spectral analysis; oligosaccharide mapping; saccharide compositional analysis; and in vitro assessment and anticoagulant activity. Oligosaccharide mapping and nuclear magnetic resonance spectroscopy showed that this human heparin is structurally similar to porcine intestinal mucosal heparin but distinctly different from bovine lung heparin. This human heparin also has substantially more in vitro anticoagulant activity than either of these pharmaceutical heparins.     

Characterization of Simian virus 40 DNA component II during viral DNA replication

Replicating molecules of Simian virus 40 DNA labeled during a short pulse with [³H]thymidine have been fractionated by ultracentrifugation methods and the open circular form (DNA component II) has been characterized. The pulse-labeled DNA component II is a relatively small constituent (1 to 3%) of the pool of replicating molecules. Examination of the circular (18 S) and linear (16 S) strands of DNA component II by alkaline sedimentation and by degradation using exonuclease III of Escherichia coli reveals that the newly synthesized DNA is principally in the linear strand. Cleavage of pulse-labeled DNA component II by an fi⁺, R-factor restriction endonuclease from E. coli demonstrates that the interruption in the pulse-labeled strand is specifically located at the termination point for replication.During a chase period of 20 minutes the amount of DNA component II increases to about 6 to 8% of the total labeled viral DNA. The kinetics of formation of superhelical, DNA component I and disappearance of replicative intermediates are linear during the chase period. After several hours of continuous labeling of replicating viral DNA, the DNA component II pool consists mainly of molecules labeled in both strands with the interruption non-specifically located in either strand. These molecules probably arise by the random introduction of single-strand breaks in newly synthesized DNA component I. During short periods of continuous labeling with [³H]thymidine, the ratio of DNA components I to II increases as a function of the pulse duration. These results support a model for 8V 40 DNA replication in which the open circular form is a precursor of the superhelical form.     

Estimating the Inbreeding Depression on Cognitive Behavior: A Population Based Study of Child Cohort

BackgroundCognitive ability tests are widely assumed to measure maximal intellectual performance and predictive associations between intelligence quotient (IQ) scores and later mental health problems. Very few epidemiologic studies have been done to demonstrate the relationship between familial inbreeding and modest cognitive impairments in children.ObjectiveWe aimed to estimate the effect of inbreeding on children’s cognitive behavior in comparison with non-inbred children.MethodologyA cohort of 408 children (6 to 15 years of age) was selected from inbred and non-inbred families of five Muslim populations of Jammu region. The Wechsler Intelligence Scales for Children (WISC) was used to measure the verbal IQ (VIQ), performance IQ (PIQ) and full scale IQ (FSIQ). Family pedigrees were drawn to access the family history and children’s inbred status in terms of coefficient of inbreeding (F).ResultsWe found significant decline in child cognitive abilities due to inbreeding and high frequency of mental retardation among offspring from inbred families. The mean differences (95% C.I.) were reported for the VIQ, being −22.00 (−24.82, −19.17), PIQ −26.92 (−29.96, −23.87) and FSIQ −24.47 (−27.35, −21.59) for inbred as compared to non-inbred children (p>0.001). The higher risk of being mentally retarded was found to be more obvious among inbred categories corresponding to the degree of inbreeding and the same accounts least for non-inbred children (p<0.0001). We observed an increase in the difference in mean values for VIQ, PIQ and FSIQ with the increase of inbreeding coefficient and these were found to be statistically significant (p<0.05). The regression analysis showed a fitness decline (depression) for VIQ (R² = 0.436), PIQ (R² = 0.468) and FSIQ (R² = 0.464) with increasing inbreeding coefficients (p<0.01).ConclusionsOur comprehensive assessment provides the evidence for inbreeding depression on cognitive abilities among children.     

Adverse Respiratory Health and Hematological Alterations among Agricultural Workers Occupationally Exposed to Organophosphate Pesticides: A Cross-Sectional Study in North India

Background

Non-protective work practices followed by farm workers during spraying of pesticides lead to occupational exposure among them.

Objective

This study is designed to explore the respiratory health and hematological profile of agricultural workers occupationally exposed to OP pesticides.

Materials and Methods

A cross sectional study was undertaken among 166 pesticide sprayers working in mango orchards of Lucknow district in North India compared with 77 controls to assess the respiratory illness, lung functions, cholinesterase levels and hematological profile. A questionnaire based survey and clinical examination for respiratory health were conducted among study subjects. Lung function test was conducted among study subjects by using spirometer. Cholinesterase level as biomarker of OP pesticides and hematological profile of study subjects were investigated in the laboratory by following the standard protocols.

Results

Overall respiratory morbidity observed among exposed subjects was 36.75%. Symptoms for respiratory illness like dry cough, productive cough, wheezing, irritation of throat and blood stained sputum were found to be significantly more (p<0.05) among pesticide sprayers than controls. Lung function parameters viz. PEFR, FEV₁, %PEFR predicted, %FEV₁ predicted and FEV₁/FVC were found to be significantly decreased (p<0.05) among pesticide sprayers as compared to controls. Exposure wise distribution of respiratory illness and lung functions among pesticide sprayers show that the exposure duration significantly elevates (p<0.05) the respiratory problems and significantly decreases (p<0.001) lung functions among pesticide sprayers. Activities of acetylcholinesterase and butyrylcholinesterase were found to be significantly depleted (p<0.001) among pesticide sprayers as compared to controls which show the exposure of OP pesticides among them. The hematological profile viz. RBC, WBC, monocytes, neutrophils, MCV, MCH, MCHC and platelet count were significantly altered (p<0.001) in pesticide sprayers than controls.

Conclusion

This study shows that the unsafe occupational exposure of OP pesticides causes respiratory illness, decreased lung functions and hematological alterations among pesticide sprayers.