Isolation of disease-tolerant cotton (Gossypium hirsutum L. cv. SVPR 2) plants by screening somatic embryos with fungal culture filtrate

We report an in vitro selection method that has led to isolation of Fusarium wilt and Alternaria leaf spot disease-tolerant plantlets in cotton (Gossypium hirsutum L. cv. SVPR2). Embryogenic callus was isolated from hypocotyl explants of cotton cultured on 5–50% Fusarium oxysporum culture filtrate-fortified callus induction medium. Somatic embryos tolerant to fungal culture filtrate (FCF) were isolated from this embryogenic callus on somatic embryo regeneration medium fortified with 40% FCF. Sixteen plantlets were selected as FCF-tolerant from 34 somatic embryos tested, which corresponds to about 47% success rate. The FCF-tolerant plants were analyzed for disease tolerance by challenging them with spores of F. oxysporum and Alternaria macrospora. Four plants were selected as F. oxysporum tolerant from a total of 24 plants tested. The selected plants showed an enhanced survival rate compared with the control when they were grown in earthen pots inoculated with 1 × 10⁵ spores/mL of F. oxysporum. From the FCF-tolerant plants, another nine randomly selected plantlets were challenged with spores of A. macrospora in order to test their tolerance to Alternaria leaf spot disease. The number of lesions per leaf significantly decreased from 8.2 to 0.9 and the lesion lengths were also reduced from 2.8 to 1.2 mm per leaf spot in these plants. Electrophoresis analysis of extracellular proteins from the FCF-tolerant plants showed enhanced secretion of proteins in the range of 24–36 kDa. Isozyme analysis by of FCF-tolerant plants by using native gels showed the presence of chitinase. Quantitative analysis showed that there was 13-fold increase in a chitinase activity in the selected FCF-tolerant plants compared to the control plants. Our results show that over-expression of chitinase enzyme leads to enhanced disease resistance against F. oxysporum and A. macrospora.     

Preparation of galactans from <Emphasis Type="Italic">Gracilaria debilis</Emphasis> and <Emphasis Type="Italic">Gracilaria salicornia</Emphasis> (Gracilariales,Rhodophyta) of Indian waters

Superior quality non-methylated and low-sulphated galactans were extracted from two Indian agarophytes namely Gracilaria debilis and G. salicornia growing naturally along the west coast of India, using an eco-friendly method developed in our laboratory. The galactans were characterised by FT-IR, ¹³C NMR, GC-MS, ICP, GPC and rheological measurements. G. debilis produced exclusively non-methylated galactan exhibiting the greatest gel strength of 650±25 g cm⁻² and lowest sulphate of 0.21±0.06%. On the contrary, G. salicornia polysaccharide was composed of non-methylated galactose (major) and mannose (minor), having gel strength of 510±25 g cm⁻² and sulphate of 0.45±0.06%. Very low heavy metal contents were determined in both the galactan samples, which may thus be potentially useful in food and biological applications.     

Characterization of a triglyceride hydrolase secreted by canine liver maintained in vitro.

These studies demonstrate that canine liver synthesizes a TGH activated by C-I but not by C-II. This TGH has properties similar to lipoprotein lipase C-I isolated from postheparin plasma of human subjects, but differs from a previously reported liver triglyceride-lipase or protamine insensitive-lipase in its sensitivity to NaCl and protamine sulfate, as well as in its requirement for a serum cofactor, C-I. These data suggest the possiblity that, in dogs, liver is a source of plasma LPLC-I.     

Haptoglobin, transferrin and serum albumin variants in the Dayaks of Sarawak.

The Land Dayaks and the Sea Kayaks of Sarawak were surveyed for haptoglobin, transferrin and serum albumin variants. The Hp1 gene frequency was 0.385 in 283 Land Dayaks as well as in 205 Sea Kayaks. The TfDChi gene frequency in 283 Land Dayaks was 0.030 and in 188 Sea Kayaks it was 0.040. Serum albumin Medan was found in one of the 188 Sea Kayaks.     

Inhibitory effect of transfer RNA on protein kinases from baker's yeast and rat skeletal muscle

Sephadex G-200 gel filtration of DNA cellulose-treated crude extracts of rat skeletal muscle, revealed a broad peak-fraction of tRNA-inhibitory protein kinases (PK) coeluted endogenous substrates. In comparison, the elution profile of baker's yeast exhibited multiple peak-fractions of tRNA-inhibiting PK. Various tRNA all showed inhibition to PK. In the presence of regulatory subunit of cyclic AMP-dependent protein kinase, tRNA did not exert synergetic inhibition on PK. Moreover, the interaction of tRNA with active muscle PK fractions could not be monitored by the increment of absorbance at 340 nm. tRNA had no significant regulatory effect on the phosphorylation of actin and myosin.     

Phenylmethylsulfonyl fluoride (PMSF) inhibits 17 beta-estradiol binding to estrogen receptor from human prostate

Estrogen receptor binding studies were performed on cytosol obtained from human benign prostatic hyperplasia (BPH) tissue. Binding assays were done in the absence or presence of various concentrations of phenylmethylsulfonyl fluoride (PMSF). Saturation analysis and Scatchard plots showed that the binding of 17 beta -estradiol to the estrogen receptor (ER) was inhibited by PMSF. The nature of the inhibition appears to be uncompetitive, as determined from double-reciprocal plots. Glycerol density gradient centrifugation analysis also confirmed the results obtained with Scatchard plots. The inhibition observed in the presence of dithiothreitol (DTT) was greater than the inhibition observed in the absence of DTT. The maximum number of binding sites (Bmax) observed in our present study was 59.1 +/- 34.1 fmol/mg protein with an equilibrium dissociation constant (KD) of 2.2 +/- 2.2 nM. Our study indicates that PMSF significantly affects 17 beta -estradiol binding to ER and consequently alters the estimation of ER in Human BPH.