Charge distribution, dipole moments and infrared spectra of some thiol and thio acids

The dipole moments of thioglycollic (2.28 D), β-mereaptopropionic (2.25 D), thiomalic (2.47 D), malic (3.12 D), and dithiodiacetic (3.17 D) acids have been measured in dioxan at 35° C. Using the scheme of Smith, Ree, Magee and Eyring, the formal charge distribution in and hence the electric moments of these acids have been evaluated, compared with the theoretical moments, and discussed in terms of their various possible structures. Infrared spectra of these acids (liquid and nujol mull) indicate association through hydrogen bonding. These bonds are broken in solution. © 1969.

Charge distribution, dipole moments and infrared spectra of some thiol and thio acids

The dipole moments of thioglycollic (2.28 D), β-mereaptopropionic (2.25 D), thiomalic (2.47 D), malic (3.12 D), and dithiodiacetic (3.17 D) acids have been measured in dioxan at 35° C. Using the scheme of Smith, Ree, Magee and Eyring, the formal charge distribution in and hence the electric moments of these acids have been evaluated, compared with the theoretical moments, and discussed in terms of their various possible structures. Infrared spectra of these acids (liquid and nujol mull) indicate association through hydrogen bonding. These bonds are broken in solution.

Heat shock response in mulberry silkworm races with different thermotolerances

The thermal sensitivity and heat shock response of the different races of the mulberry silkworm Bombyx mori have been analysed. The multivoltine race, strains C. Nichi and Pure Mysore showed better survival rates than the bivoltine race, strain NB4D2 exposed to 41 degrees C and above. In general, the fifth instar larvae and the pupae exhibited maximum tolerance compared to the early larval instars, adult moths or the eggs. Exposure up to 39 degrees C for 1 or 2 h was tolerated equally whereas temperatures above 43 degrees C proved to be lethal for all. Treatment of larvae at 41 degrees C for Ih resulted in a variety of physiological alterations including increased heart beat rates, differential haemocyte counts, enlargement of granulocytes and the presence of additional protein species in the tissues and haemolymph. The appearance of a 93 kDa protein in the haemolymph, fat bodies and cuticle, following the heat shocking of larvae in vivo was a characteristic feature in all the three strains examined although the kinetics of their appearance itself was different. In haemolymph, the protein appeared immediately in response to heat shock in C. Nichi reaching the maximal levels in 2-4 h whereas its presence was noticeable only after 2-4 h recovery time in Pure Mysore and bivoltine races. The fat body from both C. Nichi and NB4D2 showed the presence of 93 kDa, 89 kDa and 70 kDa proteins on heat shock. The haemocytes, on the other hand, expressed only a 70 kDa protein consequent to heat shock. The 93 kDa protein in the haemolymph, therefore could have arisen from some other tissue, possibly the fat body. The 93 kDa protein was detected after heat shock in pupae and adult moths as well, although the presence of an additional (56 kDa) protein was also apparent in the adults. The presence of 46 kDa and 28 kDa bands in addition to the 93 kDa band in the cuticular proteins immediately following heat shock was clearly discernible. The 70 kDa band did not show much changes in the cuticular proteins on heat shock. In contrast to the changes in protein profiles seen in tissues and haemolymph following heat shock in vivo, the heat treatment of isolated fat body or haemolymph in vitro resulted in protein degradation.

Farmers' vulnerability to climate variability in Dimapur district of Nagaland, India

Certain parts of the State of Nagaland situated in the northeastern region of India have been experiencing rainfall deficit over the past few years leading to severe drought-like conditions, which is likely to be aggravated under a climate change scenario. The state has already incurred considerable losses in the agricultural sector. Regional vulnerability assessments need to be carried out in order to help policy makers and planners formulate and implement effective drought management strategies. The present study uses an 'index-based approach' to quantify the climate variability-induced vulnerability of farmers in five villages of Dimapur district, Nagaland. Indicators, which are reflective of the exposure, sensitivity and adaptive capacity of the farmers to drought, were quantified on the basis of primary data generated through household surveys and participatory rural appraisal supplemented by secondary data in order to calculate a composite vulnerability index. The composite vulnerability index of village New Showba was found to be the least, while Zutovi, the highest. The overall results reveal that biophysical characteristics contribute the most to overall vulnerability. Some potential adaptation strategies were also identified based on observations and discussions with the villagers.

Synthesis of enantiopure bis-aziridines, bis-epoxides, and aziridino-epoxides from D-mannitol

A practical synthesis of enantiopure bis-aziridines 11 and 15, bis-epoxides 12 and 17, and aziridino-epoxides 27 and 30 is reported using inexpensive d-mannitol as the starting material. The key transformation involves the reductive cleavage of bis-benzylidene acetal 3 to form dimesylate 4, which was further converted to monoazides and diazides followed by reduction, mesylation, and cyclization to furnish the required compounds in good yields.

Features of a unique intronless cluster of class I small heat shock protein genes in tandem with box C/D snoRNA genes on chromosome 6 in tomato (Solanum lycopersicum)

Physical clustering of genes has been shown in plants; however, little is known about gene clusters that have different functions, particularly those expressed in the tomato fruit. A class I 17.6 small heat shock protein (Sl17.6 shsp) gene was cloned and used as a probe to screen a tomato (Solanum lycopersicum) genomic library. An 8.3-kb genomic fragment was isolated and its DNA sequence determined. Analysis of the genomic fragment identified intronless open reading frames of three class I shsp genes (Sl17.6, Sl20.0, and Sl20.1), the Sl17.6 gene flanked by Sl20.1 and Sl20.0, with complete 5' and 3' UTRs. Upstream of the Sl20.0 shsp, and within the shsp gene cluster, resides a box C/D snoRNA cluster made of SlsnoR12.1 and SlU24a. Characteristic C and D, and C' and D', boxes are conserved in SlsnoR12.1 and SlU24a while the upstream flanking region of SlsnoR12.1 carries TATA box 1, homol-E and homol-D box-like cis sequences, TM6 promoter, and an uncharacterized tomato EST. Molecular phylogenetic analysis revealed that this particular arrangement of shsps is conserved in tomato genome but is distinct from other species. The intronless genomic sequence is decorated with cis elements previously shown to be responsive to cues from plant hormones, dehydration, cold, heat, and MYC/MYB and WRKY71 transcription factors. Chromosomal mapping localized the tomato genomic sequence on the short arm of chromosome 6 in the introgression line (IL) 6-3. Quantitative polymerase chain reaction analysis of gene cluster members revealed differential expression during ripening of tomato fruit, and relatively different abundances in other plant parts.

Crystalline A-DNA: The X-Ray Analysis of the Fragment d(G-G-T-A-T-A-C-C)

An A-DNA type double helical conformation was observed in the single crystal X-ray structure of the octamer d(G-G-T-A-T-A-C-C), 1, and its 5-bromouracil-containing analogue, 2. The structure of the isomorphous crystals (space group P61) was solved by a search technique based on packing criteria and R-factor calculations, with use of only low order data. At the present stage of refinement the R factors are 31 % for 1 and 28 % for 2 at a resolution of 2.25 A (0.225 nm). The molecules interact through their minor grooves by hydrogen bonding and base to sugar van der Waals contacts. The stable A conformation observed in the crystal may have some structural relevance to promoter regions where the T-A-T-A sequence is frequently found.

Left-handed helices for DNA: studies on poly[d(I-C)]

Earlier, we showed that, for the D form (n = 8 and h = 3.03 A, where n is number of nucleotide units per turn and h is height per nucleotide unit) of poly[d(A-T)], both right- and left-handed double helical models are stereochemically satisfactory and give good agreement with the observed fiber diffraction data. It was also noted that the conformations of the right- and left-handed D-DNA models are very similar to those of the right- and left-handed B-DNA models. This observation was consistent with the D leads to B transition in the solid phase. As a continuation of our earlier studies, we have carried out similar experiments with poly[d(I-C)]. We could obtain a crystalline D-form pattern (n = 8, h = 3.13 A) of the fiber at 75% relative humidity (r.h.); the hydrated (r.h. approximately equal to 95%) form of the same fiber gave the classical B-form pattern (n = 10, h = 3.40 A). In the present report, we show that both right- and left-handed double-helical models are consistent with the fiber diffraction data of poly[d(I-C)] in the D-form. Theoretical energy calculations also suggest that the right- and left-handed B- and D-DNA models are almost equally stable. Hence, we conclude that the right- and left-handed double-helical models of poly[d(I-C)] in a given form (B or D) are equally likely and that the fiber diffraction data do not permit discrimination.

A reply to a discussion by D.J. Cook of the paper a reaction product of lime and silica from rice husk asha star, open

Abstract is not available.

Sequence-dependent conformation of an A-DNA double helix: The crystal structure of the octamer d(G-G-T-A-T-A-C-C)

The crystal structures of the synthetic self-complementary octamer d(G-G-T-A-T-A-C-C) and its 5-bromouracil-containing analogue have been refined to R values of 20% and 14% at resolutions of 1·8 and 2·25 Å, respectively. The molecules adopt an A-DNA type double-helical conformation, which is minimally affected by crystal forces. A detailed analysis of the structure shows a considerable influence of the nucleotide sequence on the base-pair stacking patterns. In particular, the electrostatic stacking interactions between adjacent guanine and thymine bases produce symmetric bending of the double helix and a major-groove widening. The sugar-phosphate backbone appears to be only slightly affected by the base sequence. The local variations in the base-pair orientation are brought about by correlated adjustments in the backbone torsion angles and the glycosidic orientation. Sequence-dependent conformational variations of the type observed here may contribute to the specificity of certain protein-DNA interactions.

Studies on follicular atresia: role of tropic hormone and steroids in regulating cathepsin-D activity of preantral follicles of the immature rat

The ovary of the immature female rat is comprised of primary and medium-sized preantral follicles. Upon stimulation with FSH or PMSG, the cathepsin-D activity, a representative lysosomal enzyme of granulosa cells, is reduced by 50% (P < 0.01). 17β-Estradiol at the doses tried was unable to mimic this effect. Blockade of steroidogenesis with cyanoketone also had no effect on the cathepsin-D activity of isolated granulosa cells. Dihydrotestosterone (DHT), however, at a dose of 1 mg/rat was able to inhibit PMSG's tropic action. It brought about an increase in cathepsin-D activity and reduction in steroidogenic activity of isolated granulosa cells. The atretogenic activity of DHT could be relieved by supplementation with exogenous FSH. DHT was observed to significantly reduce (P < 0.01) endogenous FSH and LH levels within 12–18 h of its injection suggesting that its atretic effect was due to its action at the pituitary rather than the gonad. In addition to the above the ability of 15 IU of PMSG to reduce cathepsin-D activity of granulosa cells was also significantly reduced (P < 0.01) if endogenous FSH was neutralized by a specific FSH antiserum. The present study suggests that as far as small and medium-sized primary and preantral follicles are concerned, FSH lack is the essential signal for onset of atresia.

Gas-crystal photoreaction: the structures of 4,4'-dimethoxy(thiobenzophenone) (I), C15H14O2S, and 4,4'-bis(dimethylamino)thiobenzophenone (II), C17H20N2S

(I): M r = 258.34, triclinic, Pi, a = 9.810 (3), b=9.635(3), e=15.015(4)A, a=79.11(2), #= 102.38 (3), y = 107.76 (3) o, V= 1308.5 A 3, Z = 4, Din= 1.318 (3) (by flotation in KI solution), D x = 1.311 g cm -3, Cu Ka, 2 = 1.5418/~, g = 20-05 cm -1, F(000) = 544, T---- 293 K, R = 0.074 for 2663 reflections. (II): M r = 284.43, monoclinic, P2~/c, a= 17.029 (5), b=6.706 (5), c= 14.629 (4), t= 113.55 (2) ° , V=1531.4A 3, Z=4, Dm=1.230(5) (by flotation in KI solution), Dx= 1.234gem -3, Mo Ka, 2 = 0.7107 A, g = 1.63 cm-1; F(000) = 608, T= 293 K, R = 0.062 for 855 reflections. The orientation of the C=S chromophores in the crystal lattice and their reactivity in the crystalline state are discussed. The C--S bonds are much shorter than the normal bond length [1.605 (4) (I), 1.665 (8) A (II) cf. 1.71 A].