Plasmonic nanoparticles assemblies templated by helical bacteria and resulting optical activity

Plasmonic nanoparticles (NPs) adsorbing onto helical bacteria can lead to formation of NP helicoids with micron scale pitch. Associated chiroptical effects can be utilized as bioanalytical tool for bacterial detection and better understanding of the spectral behavior of helical self‐assembled structures with different scales. Here, we report that enantiomerically pure helices with micron scale of chirality can be assembled on Campylobacter jejuni, a helical bacterium known for severe stomach infections. These organisms have right‐handed helical shapes with a pitch of 1–2 microns and can serve as versatile templates for a variety of NPs. The bacteria itself shows no observable rotatory activity in the visible, red, and near‐IR ranges of electromagnetic spectrum. The bacterial dispersion acquires chiroptical activity at 500–750 nm upon plasmonic functionalization with Au NPs. Finite‐difference time‐domain simulations confirmed the attribution of the chiroptical activity to the helical assembly of gold nanoparticles. The position of the circular dichroism peaks observed for these chiral structures overlaps with those obtained before for Au NPs and their constructs with molecular and nanoscale chirality. This work provides an experimental and computational pathway to utilize chiroplasmonic particles assembled on bacteria for bioanalytical purposes.Gold nanoparticles assemble onto the surface of helical bacterium, Campylobacter jejuni, producing right‐handed helices with a pitch of 1–2 microns. The bacterial dispersion acquires chiroptical activity at 500–750 nm that matches the calculated chiroplasmonic spectra. This study provides a pathway to utilize chiroplasmonic particles for monitoring shape dynamics of bacteria and identification of helical bacteria in complex microbiomes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155927/1/Supporting_information_Chirality_Manuscript_2020.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155927/2/chir23225_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155927/3/chir23225.pd

Antimicrobial Microwebs of DNA–Histone Inspired from Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs) are decondensed chromatin networks released by neutrophils that can trap and kill pathogens but can also paradoxically promote biofilms. The mechanism of NET functions remains ambiguous, at least in part, due to their complex and variable compositions. To unravel the antimicrobial performance of NETs, a minimalistic NET‐like synthetic structure, termed “microwebs,” is produced by the sonochemical complexation of DNA and histone. The prepared microwebs have structural similarity to NETs at the nanometer to micrometer dimensions but with well‐defined molecular compositions. Microwebs prepared with different DNA to histone ratios show that microwebs trap pathogenic Escherichia coli in a manner similar to NETs when the zeta potential of the microwebs is positive. The DNA nanofiber networks and the bactericidal histone constituting the microwebs inhibit the growth of E. coli. Moreover, microwebs work synergistically with colistin sulfate, a common and a last‐resort antibiotic, by targeting the cell envelope of pathogenic bacteria. The synthesis of microwebs enables mechanistic studies not possible with NETs, and it opens new possibilities for constructing biomimetic bacterial microenvironments to better understand and predict physiological pathogen responses.Microwebs with bacteria trapping and killing functions are designed to mimic neutrophil extracellular traps—an immune defense weapon to fight against invading pathogens. The composition–structure–function relationship of the synthetic structure is discussed, and the collaborative action between microwebs and antibiotics allows better elimination of pathogenic bacteria, Escherichia coli.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/1/adma201807436-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/2/adma201807436_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/3/adma201807436.pd

Long Term Effect of Organic and Inorganic Manures on Rice Productivity and Major Nutrient Dynamics in 33 Years Old Rice-Rice Cropping System of Godavari Delta

Aim: To study the “Long Term Effect of Organic and Inorganic Manures on Rice Productivity and Major nutrient dynamics in 33 years old Rice- Rice Cropping System of Godavari Delta”. Place and Duration of Study: A field experiment was carried out during kharif 2022 at Regional Agricultural Research Station, Maruteru, West Godavari district in the ongoing All India Coordinated Rice Improvement Project (AICRIP) on Long term soil fertility management in low land rice soils of Godavari delta under rice-rice cropping system. Study Design and Methodology: Treatments imposed in this study were T1: Control, T2: 50 % NPK, T3: 50% NPK + 50 % N-FYM, T4: 50 % NPK + 50% N-Green Manure, T5: 50 % NPK + 50 % N-Azospirillum, T6: FYM @ 10t/ha, T7: 100 % NPK+Zn+S, T8: 100 % NPK +Zn+S+FYM @ 5 t ha-1. All together 8 treatments laid out in RBD with three Replications. The application of fertiliser was carried out in accordance with the treatments. The prescribed fertiliser dose (90:60:60) was administered in the following forms:  urea (46% N), single superphosphate (16% P2O5), muriate of potash (60% K2O), and zinc sulphate (ZnSO4.7H2O) @ 50 kg ha-1. The total dosage of phosphorus, potassium, and zinc were applied as basal. Three equally divided applications of nitrogen were made: one at the basal, one at the tillering stage, and one at the panicle initiation stage. Well decomposed farmyard manure (FYM) manure and Pheltophorum (green leaf manure) were applied one week before transplanting. Popular cultivar of Kharif rice MTU 1064 (Amara) was used for the study. Results: Long-term application of organic and inorganic fertilizers and their combination didn’t show any marked difference on physico-chemical properties of soil (pH and EC). Bulk density was recorded lowest in FYM @ 10 t ha-1 and it was on par with (T8, T3, T4, T5). Organic carbon was observed highest in FYM @ 10 t ha-1 and it was on par with (T8 and T3). There was a significant impact of long-term application of organic and inorganic fertilizers and their combination on soil chemical properties, highest available N, P, K, S and Zn was observed highest in conjunctive treatment (T8) 100 % NPK + Zn + S + FYM @ 5 t ha-1 whereas, lowest was recorded in control.  There was a significant impact on grain and straw yields. Highest grain and straw yields were recorded in (T8) 100 % NPK + Zn + S +FYM @ 5 t ha-1 and it was on par with (T7) 100 % NPK + Zn + S. Conclusions: After the investigation, present study concludes that conjunctive and combined application of organics with inorganics improve soil physical, physico-chemical and chemical properties of the soil

Biomimetics: Antimicrobial Microwebs of DNA–Histone Inspired from Neutrophil Extracellular Traps (Adv. Mater. 14/2019)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149239/1/adma201970097.pd

Biomimetics: Antimicrobial Microwebs of DNA–Histone Inspired from Neutrophil Extracellular Traps (Adv. Mater. 14/2019)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149239/1/adma201970097.pd