Cytology and origin of a tetraploid Trichosanthes palmata Roxb.

Cytology of male plants of a tetraploid Trichosanthes palmata Roxb. has been studied. The plants showed 44 chromosomes in root tip cells. Chromosomal associations during diakinesis and early meiotic metaphase were studied. Chromosome number and morphology, high multivalent frequency, meiotic irregularities, general morphological characters and larger size of the stomata and epidermal cells compared to the diploid relative suggest that this collection is of possible autopolyploid origin.Although the plants are dioecious, cytologically distinet sex chromosomes were not detected neither in the diploids reported earlier, nor in the tetraploids described in the present study.     

Purification, physicochemical characterization, saccharide specificity, and chemical modification of a Gal/GalNAc specific lectin from the seeds of Trichosanthes dioica

A new galactose-specific lectin has been purified from the extracts of Trichosanthes dioica seeds by affinity chromatography on cross-linked guar gum. The purified lectin (T. dioica seed lectin, TDSL) moved as a single symmetrical peak on gel filtration on Superose-12 in the presence of 0.1 M lactose with an M(r) of 55 kDa. In the absence of ligand, the movement was retarded, indicating a possible interaction of the lectin with the column matrix. In SDS-PAGE, in the presence of beta-mercaptoethanol, two non-identical bands of M(r) 24 and 37 kDa were observed, whereas in the absence of beta-mercaptoethanol, the lectin yielded a single band corresponding to approximately 55,000 Da, indicating that the two subunits of TDSL are connected by one or more disulfide bridges. TDSL is a glycoprotein with about 4.9% covalently bound neutral sugar. Analysis of near-UV CD spectrum by three different methods (CDSSTR, CONTINLL, and SELCON3) shows that TDSL contains 13.3% alpha-helix, 36.7% beta-sheet, 19.4% beta-turns, and 31.6% unordered structure. Among a battery of sugars investigated, TDSL was inhibited strongly by beta-d-galactopyranosides, with 4-methylumbelliferyl-beta-d-galactopyranoside being the best ligand. Chemical modification studies indicate that tyrosine residues are important for the carbohydrate-binding and hemagglutinating activities of the lectin. A partial protection was observed when the tyrosine modification was performed in the presence of 0.2 M lactose. The tryptophan residues of TDSL appear to be buried in the protein interior as they could not be modified under native conditions, whereas upon denaturation with 8 M urea two Trp residues could be selectively modified by N-bromosuccinimide. The subunit composition and size, secondary structure, and sugar specificity of this lectin are similar to those of type-2 ribosome inactivating proteins, suggesting that TDSL may belong to this protein family.     

Preparation and preliminary application of monoclonal antibodies against Trichokirin-S1, a small ribosome-inactivating peptide from the seeds of Trichosanthes kirilowii

Trichokirin-S1,a small ribosome-inactivating peptide recently purified from the seeds ofTrichosanthes kirilowii,has potential clinical applications because of its small molecular mass.Two stablestrains of hybridomas (1F11 and 2A5) that can secrete highly specific monoclonal antibodies (mAbs) againstTrichokirin-S1 have been developed using the hybridoma technique.The isotypes of these two mAbs,1F11and 2A5,were determined to be IgG_(2a) and IgG_1,respectively.The affinity constants,which were measuredby non-competitive ELISA,were found to be 2.3×10~8 M~(-1) and 2.8×10~8 M~(-1),respectively.An immunoaffinitymethod using 2A5-coupled Sepharose 4B was successfully developed to purify Trichokirin-S1.These twoantibodies have also been used to detect Trichokirin-S1 in Western blot.     

Trichosanthes dioica Fruit Ameliorates Experimentally Induced Arsenic Toxicity in Male Albino Rats Through the Alleviation of Oxidative Stress

The present work was focused to evaluate the ameliorative property of aqueous extract of Trichosanthes dioica fruit (AQ T. dioica fruit) against arsenic-induced toxicity in male Wistar albino rats. AQ T. dioica fruit was administered orally to rats at 50 and 100 mg/kg body weight for 20 consecutive days prior to oral administration of sodium arsenite (10 mg/kg) for 10 days. Then the rats were sacrificed for the evaluation of body weights, organ weights, hematological profile, serum biochemical profile, and hepatic and renal antioxidative parameters viz. lipid peroxidation, reduced and oxidized glutathione, glutathione-S-transferase, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, and DNA fragmentation. Pretreatment with AQ T. dioica fruit at both doses markedly and significantly normalized body weights, organ weights, hematological profiles, and serum biochemical profile in arsenic-treated animals. Further, AQ T. dioica fruit pretreatment significantly modulated all the aforesaid hepatic and renal biochemical perturbations and reduced DNA fragmentation in arsenic-intoxicated rats. Therefore, from the present findings, it can be concluded that T. dioica fruit possessed remarkable value in amelioration of arsenic-induced hepatic and renal toxicity, mediated by alleviation of arsenic-induced oxidative stress by multiple mechanisms in male albino rats.     

Purification and partial characterization of a lectin from the seeds of Trichosanthes kirilowii Maximowicz

A lectin was purified from the seeds of Trichosanthes kirilowii, belonging to the family Cucurbitaceae, growing in China. The lectin is a glycoprotein of 57 kDa, consists of two subunits with apparent molecular masses of 37 and 25 kDa, is specific for galactose, and is not mitogenic for human lymphocytes.     

Detection and elimination of Begomovirus infecting Trichosanthes dioica (pointed gourd) plants in Uttar Pradesh,India

Begomovirus is widely spread on cultivated crops in India. In a survey, infected plants of Trichosanthes dioica (Pointed gourd) with the symptoms of mosaic and leaf curling were collected and checked for Begomovirus infection through PCR analysis. Application of meristem culture technique for regeneration of virus free plants of T. dioica was assessed. Plantlets were regenerated from infected plants of T. dioica through meristem culture. Regenerated plants were found Begomovirus free as evident by PCR analysis suggesting the suitability of meristem culture technique for elimination of Begomovirus from infected plants of T. dioica. This is the first report on elimination of Begomovirus in T. dioica in India.     

Tailoring the composition of novel wax esters in the seeds of transgenic Camelina sativa through systematic metabolic engineering

The functional characterization of wax biosynthetic enzymes in transgenic plants has opened the possibility of producing tailored wax esters (WEs) in the seeds of a suitable host crop. In this study, in addition to systematically evaluating a panel of WE biosynthetic activities, we have also modulated the acyl‐CoA substrate pool, through the co‐expression of acyl‐ACP thioesterases, to direct the accumulation of medium‐chain fatty acids. Using this combinatorial approach, we determined the additive contribution of both the varied acyl‐CoA pool and biosynthetic enzyme substrate specificity to the accumulation of non‐native WEs in the seeds of transgenic Camelina plants. A total of fourteen constructs were prepared containing selected FAR and WS genes in combination with an acyl‐ACP thioesterase. All enzyme combinations led to the successful production of wax esters, of differing compositions. The impact of acyl‐CoA thioesterase expression on wax ester accumulation varied depending on the substrate specificity of the WS. Hence, co‐expression of acyl‐ACP thioesterases with Marinobacter hydrocarbonoclasticus WS and Marinobacter aquaeolei FAR resulted in the production of WEs with reduced chain lengths, whereas the co‐expression of the same acyl‐ACP thioesterases in combination with Mus musculus WS and M. aquaeolei FAR had little impact on the overall final wax composition. This was despite substantial remodelling of the acyl‐CoA pool, suggesting that these substrates were not efficiently incorporated into WEs. These results indicate that modification of the substrate pool requires careful selection of the WS and FAR activities for the successful high accumulation of these novel wax ester species in Camelina seeds.     

Isolectin composition of individual clones of Urtica dioica: Evidence for phenotypic differences

Analysis of the isolectin composition of 102 individual nettle ( Urtica dioica L.) clones by ion-exchange chromatography revealed the occurrence of at least 11 different isolectins, which all had the same molecular structure and exhibited identical carbohydrate-binding specificity and agglutination properties. All 11 isolectins, however, did not occur simultaneously; 34 combinations of either 1, 2, 3, 4 or 5 isolectins were found. Since the occurrence of multiple molecular forms of the nettle agglutinin cannot be explained by the (partial) autotetraploid character of stinging nettle it is postulated to rely on the expression of a family of closely related lectin genes.     

The lipid polyester composition of Arabidopsis thaliana and Brassica napus seeds

Mature seeds of Arabidopsis thaliana and Brassica napus contain a complex mixture of aliphatic monomers derived from the non-extractable lipid polyesters deposited by various seed tissues. Methods of polyester depolymerization of solvent-extracted seeds and analysis of aliphatic monomers were compared. Sodium methoxide-catalyzed depolymerization, followed by GC analysis of the acetylated monomers, was developed for routine quantitative analysis suitable for 0.5g seed samples. In Arabidopsis seeds, the major C16 and C18 monomers identified included omega-hydroxy fatty acids and alpha,omega-dicarboxylic acids derived from palmitate, oleate and linoleate, and 9,10,18-trihydroxyoctadecenoic acid. Among monomers which can collectively be considered likely to be derived from suberin, docosan-1-ol, docosane-1,22-diol, 22-hydroxydocosanoic acid, 24-hydroxytetracosanoic acid, tetracosane-1,24-dioic acid and ferulic acid were the major species. Compared to Arabidopsis, Brassica seeds showed a roughly similar proportion of monomer classes, with the exception that alkan-1ols were 3-fold higher. Also, there were much less C24 aliphatic species and significant amounts of C14-C16 alkan-1ols, including iso- and anteiso-methyl branched compounds. Dissection and analysis of mature Brassica seeds showed that the trihydroxy C18:1 fatty acid was found mainly in the embryo, while ferulate, fatty alcohols and C22 and C24 species were specific to the seed coat plus endosperm.     

Hanultarin, a cytotoxic lignan as an inhibitor of actin cytoskeleton polymerization from the seeds of Trichosanthes kirilowii

Bioactivity-directed fractionation of extracts from the seeds of Trichosanthes kirilowii led to the isolation of (-)-1-O-feruloylsecoisolariciresinol (2), named hanultarin, In addition, four known lignans were also isolated, including (-)-secoisolariciresinol (1), 1,4-O-diferuloylsecoisolariciresinol (3), (-)-pinoresinol (4), and 4-ketopinoresinol (5). Their structures were elucidated on the basis of spectroscopic data. Compounds 2 and 3 exhibited strong cytotoxic effects against human lung carcinoma A549 cells, melanoma SK-Mel-2 cells, and mouse skin melanoma B16F1 cells with IC(50) ranges of 3-13 microg/mL. Compound 2 showed an inhibitory effect on the polymerization of the actin cytoskeleton in normal epidermal keratinocyte (HaCaT cells), suggesting unique biological properties of compound 2 compared to those of the other isolates.     

Amino Acid composition of germinating cotton seeds

Total and free amino acid composition of germinating cotton seeds (Gossypium hirsutum L.) was determined. The germinating seeds were separated into cotyledon and developing axis fractions daily and the composition of each tissue was summed to get the whole seed composition. By separating the developing seeds into these two tissue fractions, and determining total and free amino acids, a balance sheet was developed for each amino acid. This technique allowed changes in distribution with time of each amino acid to be followed in each tissue. Data for total content and amount in protein of each amino acid are presented. Asparagine increased in the whole seed, and most of this increase was found in the free pool of the developing axis. Other amino acids (e.g. arginine, glutamic acid) increased in the free pool but showed an over-all decrease, indicating that they were being metabolized. Amino acid contents of storage and nonstorage protein isolates were determined.     

The effects of soil metals on the composition of oil of Paeonia ostii seeds

Peony seed oil has been known to have a high value for health due to the high content of unsaturated fatty acid. However, few studies have investigated which factors impact the oil quality and composition of seeds in the traditional mining cultivation area. In the present study, the investigation was conducted in 30 cultural field sites. Significantly negative relationships were found between Cu content in soils or leaves and linoleic and unsaturated fatty acids. Further tests revealed that Cu evidently accumulated in leaves. This demonstrated Cu content in soils was the important factor that influenced linoleic acid content and unsaturated fatty acid content. Such proposition must be considered when cultivating groups of plant toward expanding oil production.     

The effect of smectite composition on the catalysis of peptide bond formation

Clay-catalyzed glycine and diglycine oligomerizations were performed as drying/wetting cycles at 80°C. Two trioctahedral smectites (hectorite and saponite), three pure montmorillonites, a ferruginous smectite, an Fe(II)-rich smectite, and three smectites containing goethite admixture were used as catalysts. Highest peptide bond formation was found with trioctahedral smectites. About 7% of glycine was converted to diglycine and diketopiperazine on hectorite after 7 days. In the case of dioctahedral smectites, highest yields were achieved using clays with a negative-layer charge localized in the octahedral sheets (up to 2% of converted glycine after 7 days). The presence of Fe(II) in clay is reflected in a higher efficiency in catalyzing amino acid dimerization (about 3.5% of converted glycine after 7 days). The possible significance of the results for prebiotic chemistry is discussed. Received: 20 February 1996 / Accepted: 26 April 1996