Camels' milk: for drinking only?

Camels' milk, women's milk and cows' milk were kept at 30 degrees C and refrigerated at 4 degrees C. This explains the necessity to immediately freeze milk if it needs to be kept even for a few days. Cows' milk remained good for days if stirred and then turned sour, enabling the making of cheeses and butter. Camels' milk did not sour at 4 degrees C for up to 3 months. This means that camels' milk is mainly good only for drinking, as was promised to this animal by the Prophet.     

CNDO calculations on the conformational structure of acetylcholine

Molecular orbital theory in the CNDO framework has been used to calculate the torsional angles which lead to minimum energy conformations in acetylcholine. The calculated angles agree well with the experimental observations on acetylcholine and its derivatives. The results have been compared with the earlier predictions based on extended Hückel theory and van der Waal pairwise interactions.     

To what end does nature produce superoxide? NADPH oxidase as an autocrine modifier of membrane phospholipids generating paracrine lipid messengers

Production of superoxide anion O2<sup>••- by the membrane-bound enzyme NADPH oxidase of phagocytes is a long-known phenomenon; it is generally assumed that O2• kill bacterial intruders. The details and the chemistry of the killing process have, however, remained a mystery. Isoforms of NADPH oxidase exist in membranes of nearly every cell, suggesting that reactive oxygen species (ROS) participate in intra- and intercellular signaling processes. What the nature of the signal is exactly, how it is transmitted, and what structural characteristics a receptor of a "radical message" must have, have not been addressed convincingly. This review discusses how the action of messengers is in agreement with radical-specific behavior.

In search for the smallest common denominator of cellular free radical activity we hypothesize that O2•e acid, HO2&bull under primordial conditions as regulators of membrane mechanics and that isoprostanes, widely used markers of "oxidative stress", may be an adventitious correlate of this biologic activity of O2•location="post" arrange="compact">2&bullre is presented that suggests that O2•location="post" arrange="compact">2&bullfying cell membranes, help other agents gain access to the hydrophobic region of phospholipid bilayers and hence contribute to lipid-dependent signaling cascades. With this, O2•location="post" arrange="compact">2&bullndispensable adjuvants for the generation of cellular signals, for membrane transport, channel gating and hence, in a global sense, for cell viability and growth. We also suggest that many of the allegedly O2•ial pathologies and carcinogenic derailments are due to membrane-modifying activity rather than other chemical reactions of O2•location="post" arrange="compact">2&bull this picture is the potential evolution of the "radical theory of ageing" to a "lipid theory of aging".</sup>     

Genome wide association studies (GWAS) of spot blotch resistance at the seedling and the adult plant stages in a collection of spring barley

Spot blotch (SB) in barley is caused by the fungal pathogen Cochliobolus sativus and considered one of the major constraints to successful barley production. Resistance to C. sativus was evaluated, using a barley collection of 336 genotypes (AM-2014), at the seedling and adult stages. Seedling resistance was evaluated by using a mixture of 19 virulent isolates in Morocco. Virulent isolates prevalent in Uttar Pradesh were used for phenotyping resistance at the adult stage in India. The AM-2014 panel was genotyped with 9-K single-nucleotide polymorphism (SNP) markers using iSelect Illumina Infinium. Genome wide association studies (GWAS) were carried out using SNP markers, infection responses, disease severity, and area under the disease progress curve (AUDPC). The mixed linear model was employed in TASSEL using principal component analysis (PCA) and Kinship matrix (K) as covariates. Higher SB severity, 82.3?±?13.5 (mean?±?SD), was recorded at the Banaras Hindu University (BHU) compared to 47.6?±?15.0 at the Narendra Dev University of Agriculture and Technology (NDUAT). Nine QTL, Rcs-qtl-1H-126.9, Rcs-qtl-2H-148.16, Rcs-qtl-3H-25.27, Rcs-qtl-5H-80.35, Rcs-qtl-6H-58.24, Rcs-qtl-7H-29.62, Rcs-qtl-7H-29.72, Rcs-qtl-7H-32.81, and Rcs-qtl-7H-34.74, were detected for SB resistance at the seedling stage. For SB severity at the adult stage, a QTL, Rcs-qtl-7H-32.81, was detected at BHU while seven QTL, Rcs-qtl-2H-91.09, Rcs-qtl-3H-145.64, Rcs-qtl-4H-14.43, Rcs-qtl-6H-6.49, Rcs-qtl-7H-114.43, Rcs-qtl-7H-151.66, and Rcs-qtl-7H-150.36, were found for SB severity at NDUAT. Three QTL, Rcs-qtl-4H-18.61, Rcs-qtl-4H-67.91, and Rcs-qtl-5H-110.25, were significant for AUDPC of SB at BHU. The QTLs reported in this study are important to advance marker-assisted selection and gene pyramiding of SB resistance in South Asia and North Africa in future.     

Convergent donor and acceptor substrate utilization among kinase ribozymes

Accommodation of donor and acceptor substrates is critical to the catalysis of (thio)phosphoryl group transfer, but there has been no systematic study of donor nucleotide recognition by kinase ribozymes, and there is relatively little known about the structural requirements for phosphorylating internal 2′OH. To address these questions, new self-phosphorylating ribozymes were selected that utilize ATP(gammaS) or GTP(gammaS) for 2′OH (thio)phosphorylation. Eight independent sequence families were identified among 57 sequenced isolates. Kinetics, donor nucleotide recognition and secondary structures were analyzed for representatives from each family. Each ribozyme was highly specific for its cognate donor. Competition assays with nucleotide analogs showed a remarkable convergence of donor recognition requirements, with critical contributions to recognition provided by the Watson–Crick face of the nucleobase, lesser contributions from donor nucleotide ribose hydroxyls, and little or no contribution from the Hoogsteen face. Importantly, most ribozymes showed evidence of significant interaction with one or more donor phosphates, suggesting that—unlike most aptamers—these ribozymes use phosphate interactions to orient the gamma phosphate within the active site for in-line displacement. All but one of the mapped (thio)phosphorylation sites are on unpaired guanosines within internal bulges. Comparative structural analysis identified three loosely-defined consensus structural motifs for kinase ribozyme active sites.     

cAMP production by adenylyl cyclase G induces prespore differentiation in Dictyostelium slugs

Encystation and sporulation are crucial developmental transitions for solitary and social amoebae, respectively. Whereas little is known of encystation, sporulation requires both extra- and intracellular cAMP. After aggregation of social amoebae, extracellular cAMP binding to surface receptors and intracellular cAMP binding to cAMP-dependent protein kinase (PKA) act together to induce prespore differentiation. Later, a second episode of PKA activation triggers spore maturation. Adenylyl cyclase B (ACB) produces cAMP for maturation, but the cAMP source for prespore induction is unknown. We show that adenylyl cyclase G (ACG) protein is upregulated in prespore tissue after aggregation. acg null mutants show reduced prespore differentiation, which becomes very severe when ACB is also deleted. ACB is normally expressed in prestalk cells, but is upregulated in the prespore region of acg null structures. These data show that ACG induces prespore differentiation in wild-type cells, with ACB capable of partially taking over this function in its absence.     

NMR and Molecular Dynamics Studies of Tachykinins: Conformation of Substance P Fragment 4-11

Abstract

The conformation of the C-terminal octapeptide fragment of Substance P (SP_4-11, Pro-GlnGln-Phe-Phe-Gly-Leu-Met-NH₂) has been investigated by 2D-NMR and MD methods. The octapeptide exists in a blend of conformations. The molecule seems to shuttle between conformations with y-bends either at Phe5 or Gly6 or Gln3 or Leu7 and between a nearly extended structure.     

Use of intercross outbred mice and single nucleotide polymorphisms to map skin cancer modifier loci

Car-R and Car-S outbred mouse lines, phenotypically selected for resistance and susceptibility to skin carcinogenesis respectively, show significant linkage disequilibrium (LD) at genetic markers mapping on chromosomal regions where skin cancer modifier loci (Skts3, Skts1, and Psl1 on Chrs 5, 7, and 9 respectively) have been mapped in standard crosses. Analysis of these regions for genetic linkage with skin cancer phenotypes in 245 (Car-R × Car-S)F₂ intercross mice, by using single nucleotide polymorphisms (SNPs), revealed significant linkage at a possible allelic form of the Skts1 locus, whose mapping region was shortened to a <5.5-cM interval near the Tyr locus. The Car-derived Skts1 locus was linked with papilloma multiplicity and latency by a recessive inheritance of the susceptibility allele. Putative loci on Chr 5 (Skts3) and 9 (Psl1) showed no significant linkage. These results point to the important role of the Stks1 locus in mouse skin tumorigenesis in independent crosses. The shortened Skts1 mapping region should facilitate the identification of candidate genes. Received: 23 June 2000 / Accepted: 22 November 2000