Germinating pigeonpea (Cajanus cajan) seeds secrete factor(s) having antiethylene-like effects

Germinating pigeonpea seeds were found to release factor(s), which dramatically altered the growth pattern of rice seedlings. This included an increased sensitivity of roots to gravity, an increase in seminal root length, and increased density of branch roots on the seminal root and suppression of root hair formation. Furthermore, the known characteristic responses of rice to ethylene (namely, coleoptile growth promotion and induction of senescence) were inhibited by the presence of these factor(s). This altered growth pattern of rice seedlings was similar to that brought about by the ethylene-antagonist, silver nitrate. Further, the change in growth pattern in rice was specifically reversed by ethrel. In addition, in wild-type Arabidopsis thaliana these factors suppressed formation of root hair, the development of which is known to be promoted by ethylene. In contrast, in a mutant A. thaliana which shows constitutive ethylene response ( ctr1-1 ), the factors failed to inhibit root hair formation. These observations indicated that germinating pigeonpea seeds secrete factor(s), which have antiethylene-like effects.     

Effect of hypocholesterolemic agents of plant origin on catecholamine biosynthesis in normal and cholesterol fed rabbits

The effect of lipid lowering agents of plant origin garlic oil and guggulipid on the levels of catecholamine and dopamine Β-hydroxylase activity of normal and cholesterol fed rabbit tissues has been studied. The catecholamine levels and enzyme activity were found to be decreased in cholesterol (500 mg/kg body wt) fed animals. The feeding of garlic oil (5 mg/kg body wt) and guggulipid (100 mg/kg body wt) an exudate ofCommiphora mukul, to normal rabbits caused significant increase in the dopamine-Β-hydroxylase activity and catecholamine levels, while the feed helped the hypercholesterolemic rabbits to recover the decrease in catecholamine biosynthesis C.D.R.I. Communication No. 3435.     

Bovine aortic chondroitin sulphate- and dermatan sulphate-containing proteoglycans. Isolation, fractionation and chemical characterization.

1. Guanidinium chloride (4M) in the presence of proteinase inhibitors extracted 90% of bovine aorta galactosaminoglycans as proteoglycans that were subsequently purified by ion-exchange and gel chromatography. 2. Fractionation of the calcium salts of the purified proteoglycans with increasing concentration of ethanol yielded fractions PG-25 (28%), PG-35 (45%) and PG-50 (37%). 3. Fraction PG-50 contained proteochondroitin 6-sulphate, whereas fractions PG-25 and PG-35 were proteodermatan sulphates of greatly different carbohydrate composition; the molar proportions of L-iduronate-N-acetylgalactosamine 4-sulphate, D-glucuronate-N-acetyl-galactosamine 4-sulphate and D-glucuronate-N-acetylgalactosamine 6-sulphate were 75: 18 :7 in fraction PG-25 and 14 :46 :40 in fraction PG-35. 4. The presence of alternating or mixed sequences with L-iduronate- and D-glucuronate-containing repeating disaccharides was indicated by the formation of tetrasaccharides after chondroitinase AC digestion (single L-iduronate residues) and by the release of fragments containing four or five consecutive D-glucuronate-N-acetylgalactosamine repeats after periodate oxidation and alkaline elimination. 5. The amino acid compositions of fractions PG-25 and PG-35 were similar and markedly different from that of fraction PG-50, which also contained more side chains.     

A single mutation affects L-serine deaminase, L-leucyl-, L-phenylalanyl-tRNA protein transferase, and proline oxidase activity in Escherichia coli K-12.

A mutation at a single locus, wyb, results in several phenotypic changes in Escherichia coli K-12. The Wyb- phenotype includes: (i) an increase in L-serine deaminase activity, together with a loss of inducibility by L-leucine; (ii) an absence of L-leucyl-, L-phenylalanyl-tRNA protein transferase activity; (iii) inducibility of proline oxidase by proline; and (iv) a loss of ability to use maltose as a carbon and energy source.     

Effect of picroliv on glutathione metabolism in liver and brain of Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, the active principle from Picrorhiza kurrooa, at a dose of 6 mg/kg, po for two weeks showed significant protection against changes in liver and brain glutathione metabolism of Plasmodium berghei infected Mastomys natalensis. The depletion of reduced glutathione level and inhibition of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities due to P. berghei infection were markedly recovered by picroliv. The increased levels of lipid peroxidation products in damaged tissues were also reduced along with the recovery of glutathione metabolism.     

Development of thermotolerance in Neurospora crassa by heat shock and other stresses eliciting peroxidase induction.

Hyperthermia, CdCl2, sodium arsenite, and H2O2 led to the rapid appearance of high levels of peroxidase in Neurospora crassa cultures and induced tolerance toward normally lethal temperatures in 60-h-old colonies. Intracellular superoxide dismutase levels did not correlate with the development of thermotolerance.     

Contributions to the cytology of endosperm in some angiosperms-VIII.Chrysanthemum carinatum L.

Cytological studies ofChrysanthemum carinatum have shown that the endosperm was free nuclear in the beginning, but, as the wall formation commenced very early, it was cellular for most of its life. The endosperm, in general, was triploid with 3n=27 chromosomes, but polyploidy (6n) and aneuploidy also occurred in a small number of cells.Although most of the nuclei in the main part of the endosperm were uniform in size and shape, they showed some variation in the haustorial region. The possible cause of this variation has been suggested to be endoduplication.Mitotic aberrations such as bridges, laggards and multipolar divisional stages appear to be the probable causes for the failure of endosperm in some of the immature seeds, resulting in a low seed set.     

Binding mode of SARS-CoV-2 fusion peptide to human cellular membrane

Infection of human cells by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) relies on its binding to a specific receptor and subsequent fusion of the viral and host cell membranes. The fusion peptide (FP), a short peptide segment in the spike protein, plays a central role in the initial penetration of the virus into the host cell membrane, followed by the fusion of the two membranes. Here, we use an array of molecular dynamics simulations that take advantage of the highly mobile membrane mimetic model to investigate the interaction of the SARS-CoV2 FP with a lipid bilayer representing mammalian cellular membranes at an atomic level and to characterize the membrane-bound form of the peptide. Six independent systems were generated by changing the initial positioning and orientation of the FP with respect to the membrane, and each system was simulated in five independent replicas, each for 300 ns. In 73% of the simulations, the FP reaches a stable, membrane-bound configuration, in which the peptide deeply penetrated into the membrane. Clustering of the results reveals three major membrane-binding modes (binding modes 1–3), in which binding mode 1 populates over half of the data points. Taking into account the sequence conservation among the viral FPs and the results of mutagenesis studies establishing the role of specific residues in the helical portion of the FP in membrane association, the significant depth of penetration of the whole peptide, and the dense population of the respective cluster, we propose that the most deeply inserted membrane-bound form (binding mode 1) represents more closely the biologically relevant form. Analysis of FP-lipid interactions shows the involvement of specific residues, previously described as the “fusion-active core residues,” in membrane binding. Taken together, the results shed light on a key step involved in SARS-CoV2 infection, with potential implications in designing novel inhibitors.