MORPHOLOGICAL AND EMBRYOLOGICAL STUDIES ON THE LEMNACEAE. I. THE FLORAL STRUCTURE AND GAMETOPHYTES OF LEMNA PAUCICOSTATA

Maheshwari, Satish C., and R. N. Kapil. (U. Delhi, Delhi, India.) Morphological and embryological studies on the Lemnaceae. I. The floral structure and gametophytes of Lemna paucicostata. Amer. Jour. Bot. 50(7): 677–686. Illus. 1963.—In Lemna paucicostata, a locally occurring member of the Lemnaceae, the plant body is represented by a frond which is devoid of lignified elements. The root shows a winged root sheath but does not have root hairs. There are no distinctive layers like the endodermis and xylem. The male archesporium is hypodermal and differentiates normally as in other angiosperms into parietal and sporogenous layers. The tapetum is single-layered and plasmodial. The partition walls of the anther are not derived by sterilization of the sporogenous cells as believed earlier. The microspore tetrads are isobilateral and decussate, the meiotic divisions being successive. The pollen grains are shed at the 3-celled stage. The ovary contains a single hemianatropous, bitegminal and crassinucellar ovule. The development of the embryo sac conforms to the Allium type.     

Plasmid elimination from clinical isolates of Echerichia coli by ciprofloxacin and other inhibitors of DNA gyrase

Summary The susceptibility of 50 drug resistant strains of Escherichia coli of human gut was determined against ciprofloxacin, acridine orange (AO) and sodium dodecyl sulphate (SDS). Curing efficacy of these agents were worked out at subminimal inhibitory concentrations. Ciprofloaxacin was found a better curing agent for E coli R-plasmids, eliminating R-factors from 48% of the strains followed by SDS and AO which eliminated 24% and 20% of the drug resistance determinants, respectively. Elimination of R-plasmids was found dependent on the concentrations of curing agents and nature of R-plasmids.     

Toddanol and toddanone,two coumarins from Toddalia asiatica

Two new constituents isolated from the roots of Toddalia asiatica and designated as toddanol and toddanone have been characterized as 5,7-dimethoxy-6-(2-hydroxy-3-methylbut-3-enyl)coumarin (1) and 5,7-dimethoxy-6-(3-methyl-2-oxobutanyl)coumarin (3), respectively, by spectral analysis and interconversion experiments.     

New alkaloids from Glycosmis mauritiana

Chemical investigation of the roots of G. mauritiana resulted in the isolation of two new alkaloids; 1-hydroxy-3-methoxy-2-(3-methylbut-2-enyl)-N-methylacridan-9-one (1) and 4,8-dimethoxy-3-(3-methylbut-2-enyl)-N-methyl-2-quinolone (6). The structures of these new bases have been established by chemical and spectroscopic methods and confirmed in the case of 6 by its synthesis. Interestingly, the formic acid-catalysed cyclisation of 1 gave the dealkylated product 3 along with the pyrano-[2, 3-a]-acridine (4).     

Dietary Mannan-oligosaccharides potentiate the beneficial effects of Bifidobacterium bifidum in broiler chicken

This study investigated the effects of dietary Bifidobacterium bifidum (BFD) and mannan-oligosaccharide (MOS), as a synbiotic, on the production performance, gut microbiology, serum biochemistry, antioxidant profile and health indices of broiler chicken. Six dietary treatments were T1 (negative control), T2 (positive control-20 mg antibiotic BMD kg⁻¹ diet; BMD: bacitracin methylene disalicylate), T3 (0·1% MOS + 10⁶ CFU BFD per g feed), T4 (0·1% MOS + 10⁷ CFU BFD per g feed), T5 (0·2% MOS + 10⁶ CFU BFD per g feed) and T6 (0·2% MOS + 10⁷ CFU BFD per g feed). Significantly (P < 0·01) better growth performance and efficiency was observed in birds supplemented with 0·2% MOS along with 10⁶ CFU BFD per g of feed compared to BMD and control birds. Supplementation with 0·2% MOS along with either 10⁶ or 10⁷ CFU BFD per g feed reduced (P < 0·01) the gut coliform, Escherichia coli, total plate count, and Clostridium perfringens count and increased the Lactobacillus and Bifidobacterium count. Significantly (P < 0·01) higher serum and liver antioxidant enzyme pool, serum HDL cholesterol and lower serum glucose, triglyceride, total cholesterol, cardiac risk ratio, atherogenic coefficient and atherogenic index of plasma were observed in birds supplemented with 0·2% MOS along with 10⁶ CFU BFD per g of feed compared to control or BMD supplemented birds. Better production performance, gut microbial composition, serum biochemistry, antioxidant profile and health indices were depicted by broiler chicken supplemented with 0·2% MOS and 10⁶ CFU BFD per g of feed.     

p-Toluenesulfonyl Chloride Catalysed Facile Synthesis of O-benzyl-l-amino Acids and Their In Vitro Evaluation

International Journal of Peptide Research and Therapeutics - Protection and subsequent deprotection of amino acid functional groups play a key role in regioselective peptide synthesis. For...     

Unifying Charge Generation,Recombination, and Extraction in Low‐Offset Non‐Fullerene Acceptor Organic Solar Cells

Even though significant breakthroughs with over 18% power conversion efficiencies (PCEs) in polymer:non‐fullerene acceptor (NFA) bulk heterojunction organic solar cells (OSCs) have been achieved, not many studies have focused on acquiring a comprehensive understanding of the underlying mechanisms governing these systems. This is because it can be challenging to delineate device photophysics in polymer:NFA blends comprehensively, and even more complicated to trace the origins of the differences in device photophysics to the subtle differences in energetics and morphology. Here, a systematic study of a series of polymer:NFA blends is conducted to unify and correlate the cumulative effects of i) voltage losses, ii) charge generation efficiencies, iii) non‐geminate recombination and extraction dynamics, and iv) nuanced morphological differences with device performances. Most importantly, a deconvolution of the major loss processes in polymer:NFA blends and their connections to the complex BHJ morphology and energetics are established. An extension to advanced morphological techniques, such as solid‐state NMR (for atomic level insights on the local ordering and donor:acceptor π? π interactions) and resonant soft X‐ray scattering (for donor and acceptor interfacial area and domain spacings), provide detailed insights on how efficient charge generation, transport, and extraction processes can outweigh increased voltage losses to yield high PCEs.     

Identification of Avramr1 from Phytophthora infestans using long read and cDNA pathogen-enrichment sequencing (PenSeq)

Potato late blight, caused by the oomycete pathogen Phytophthora infestans, significantly hampers potato production. Recently, a new Resistance to Phytophthora infestans (Rpi) gene, Rpi-amr1, was cloned from a wild Solanum species, Solanum americanum. Identification of the corresponding recognized effector (Avirulence or Avr) genes from P. infestans is key to elucidating their naturally occurring sequence variation, which in turn informs the potential durability of the cognate late blight resistance. To identify the P. infestans effector recognized by Rpi-amr1, we screened available RXLR effector libraries and used long read and cDNA pathogen-enrichment sequencing (PenSeq) on four P. infestans isolates to explore the untested effectors. Using single-molecule real-time sequencing (SMRT) and cDNA PenSeq, we identified 47 highly expressed effectors from P. infestans, including PITG_07569, which triggers a highly specific cell death response when transiently coexpressed with Rpi-amr1 in Nicotiana benthamiana, suggesting that PITG_07569 is Avramr1. Here we demonstrate that long read and cDNA PenSeq enables the identification of full-length RXLR effector families and their expression profile. This study has revealed key insights into the evolution and polymorphism of a complex RXLR effector family that is associated with the recognition by Rpi-amr1.