Induced Vine Mutant in Vigna mungo

Pure dry seeds of variety T₉ of Vigna mungo were irradiated by 10, 20 and 30 kR of gamma rays at 33 °C followed by post irradiation treatment with 0.25 % EMS in phosphate buffer (pH 7.0) at 30 ± 1 °C. Vine mutants were isolated from segregating families after 20 kR and 10kR ± EMS treatment. The genetic nature of the mutants was tested by crossing with the wild type. The segregation in F² proved the mutant to be monogenic recessive. The mutant showed slight improvement in protein content and marked improvement in yield of seeds.     

Slow-growth conservation of potato microplants: efficacy of ancymidol for long-term storage in vitro

Ancymidol was investigated as an alternative mediumsupplement to mannitol for slow-growth conservation ofpotato microplants in vitro. Differentconcentrations of ancymidol (0, 5, 10, 15, 20, 25, 30,35 and 40 M) were tested in slow-growthmedia based on MS medium supplemented with either 30or 60 gl^-1 sucrose. The cultures were conservedunder a 16-h photoperiod at two temperature regimesi.e. 24 ± 1 ^°C and 6 ± 1 ^°C. Therewere significant interactions between ancymidol andother factors such as sucrose, temperature andgenotype for microplant survival, microshoot heightand overall microplant growth. Ancymidol did have abeneficial effect on culture viability after prolongedmaintenance in vitro. The growth-inhibitingeffect of ancymidol persisted through a 16-monthculture period. Combined effect of ancymidol, sucroseand temperature showed that optimum culture viabilityand desirable microplant growth were obtained when thecultures were grown in MS medium supplemented with 10M ancymidol plus 60 gl^-1 sucrose at6 ± 1 ^°C. Vitrification and flaccidity, whichare very frequently observed in potato microplantcultures during prolonged maintenance in vitrounder osmotic stress (mannitol), were not observedwhen the microplants were conserved in ancymidolmedia. Genetic stability of potato microplantsconserved in ancymidol media was evaluated usingrandomly amplified polymorphic DNA (RAPD)fingerprints. Ancymidol did not induce any detectablegenetic variation in genomic DNA as visualized by theabsence of either any additional RAPD fragment oralterations in RAPD fragment patterns.     

Production of Brassica napus × Raphanobrassica Hybrids by Embryo Rescue: An Attempt to Introduce Shattering Resistance into B. napus

Intergeneric hybridization is one of the effective methods to broaden the genetic base of cultivated species. Raphanus sativus, a member of the subtribe Raphaninae, has very hard pods at threshing time. In an attempt to transfer shattering resistance to Brassica napus, Raphanobrassica was used as the male parent in crosses with Brassica napus. Plantlets were obtained by embryo rescue and were further multiplied in vitro by micropropagation of nodal segments. Morphology, cytology and DNA analysis confirmed the hybrid nature of these plants. They were backcrosscd with Brassica napus and the progeny was raised. Plants of BC₁ and BC₂ generations showed wide variation in morphology, chromosome number and pollen fertility. Some of the plants showed up to 95 % pollen fertility and resistance to shattering, indicating the potential for developing B. napus with resistance to shattering.     

Sex identification in Encephalartos natalensis (Dyer and Verdoorn) using RAPD markers

All cycads are strictly dioecious with a long juvenile stage. Currently, there is no method available to determine the sexuality of seedlings prior to the onset of cone formation. This study aimed to develop a sex specific Random Amplified Polymorphic DNA (RAPD) marker for Encephalartos natalensis. Initially, 140 primers were used to amplify the bulk DNA of five individuals each of known male and female sexuality. While a high degree of polymorphism was observed in the amplification profiles of male and female plants, only primer OPD-20 generated a specific band (∼850 bp) in female DNA. To validate this observation, this primer was re-tested with 69 individuals of E. natalensis. The 850 bp DNA band was present in all 38 female individuals tested and it was consistently absent in all 31 male plants tested. The result offers a rapid and simple test to determine sexuality of E. natalensis seedlings at early stages of development, before the onset of reproductive maturity thereby saving time and economic resources when cultivating these specimens.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

Enarthrocarpus lyratus-based cytoplasmic male sterility and fertility restorer system in Brassica rapa

Substituting the nuclear genome of Brassica rapa into the cytoplasmic background of Enarthrocarpus lyratus through backcross substitution helped in developing cytoplasmic male sterility (CMS). Alloplasmic male sterile plants had pale green leaves, small flowers with narrow petals and rudimentary anthers. Female fertility, low initially, improved considerably with advanced backcross generations. Male sterility expression was stable throughout the growing season. Except for EC 339014, all B. rapa accessions (38) evaluated were partial maintainers of the male sterility. Introgression of gene(s) for fertility restoration from the cytoplasm donor species was facilitated by homoeologous pairing between B. rapa and E. lyratus genomes, as was apparent from the very frequent occurrence of a trivalent in the monosomic addition plants (2n = 10 II + 1 I). Backcrossing of fertile monosomic addition plants with B. rapa led to the recovery of male fertile plants possessing the stable euploid chromosome number (2n = 20). These plants restored male fertility in crosses with different (lyr) CMS B. rapa genotypes, confirming the introgression of fertility restorer gene(s) from E. lyratus, the cytoplasm donor species.     

Expression of male sterility in alloplasmic Brassica juncea with Erucastrum canariense cytoplasm and the development of a fertility restoration system

An alloplasmic mustard, Brassica juncea, has been synthesized by placing its nucleus into the cytoplasm of the related wild species Erucastrum canariense to express cytoplasmic male sterility. To achieve this, the sexual hybrid E. canariense (2n=18, E^cE^c) ×Brassica campestris (2n= 20, AA) was repeatedly backcrossed to B. juncea (2n= 36, AABB). Cytoplasmic male‐sterile (CMS) plants were recovered in the BC₄ generation. These plants are a normal green and the flowers have slender, non‐dehiscing anthers that contain sterile pollen. Nectaries are well developed and female fertility is > 90%. The fertility restoration gene was introgressed to CMS B. juncea from the cytoplasmic donor E. canariense through pairing between chromosomes belonging to B. juncea with those of the E. canariense genome. The restorer plants have normal flowers, with well‐developed anthers containing fertile pollen. Meiosis proceeds normally. Pollen and seed fertility averaged 90% and 82%, respectively. F₁ hybrids between CMS and the restorer are fully pollen fertile and show normal seed set. Preliminary results indicate that restoration is achieved by a single dominant gene. The constitution of the organelle genomes of the CMS, restorer and fertility restored plants is identical, as revealed by Southern analysis using mitochondrial and chloroplast probes atp A and psb D, respectively.     

Rumen microbial variation and nutrient utilisation in mithun (Bos frontalis) under different feeding regimes

The aim of the study was to investigate the effect of feeding different diets on fermentation, enzyme activities and microbial population in the rumen fluid of mithun (Bos frontalis). In a randomized block design, 20 male mithun (6–8 months of age, 152 ± 12.6 kg body weight) were randomly divided into four experimental groups (n = 5/group) and fed experimental diets ad libitum for 180 days. The diet R₁ contained tree foliages (TF), R₂ comprised of 50% concentrate mixture (CM) and 50% TF, R₃ contained 50% CM and 50% rice straw, and R₄ contained 50% CM, 25% TF and 25% rice straw. Rumen liquor was collected at 0 and 180 days of the experiment for estimation of different ruminal parameters and a digestion trial was conducted at the end of the experiment. Rumen fluid was analysed for pH, ammonia nitrogen (NH₃‐N), total‐N, ruminal enzymes, short chain fatty acid (SCFA) and microbial profile. The relative quantification of ruminal microbes was carried out with real‐time PCR using bacteria as the house keeping gene. The dry matter intake, nutrients digestibility, body weight gain, NH₃‐N, total‐N, carboxymethyl cellulase, avicelase, xylanase, amylase, protease and molar proportion of butyrate were (p < 0.05) higher in mithun fed R₂, R₃ and R₄ compared to those fed R₁ diet. In contrast, increased (p < 0.05) ruminal pH, molar proportion of acetate and, acetate to propionate ratio was recorded in mithun fed only TF than those fed concentrate supplemented diets. Similarly, an increase (p < 0.05) in the population of Fibrobacter succinogenes, Ruminococcus flavefaciens and total bacteria were evident in mithun fed R₂, R₃ and R₄ compared to those fed R₁. Therefore, it is concluded that TF 25% and/or rice straw 25% along with CM 50% may be fed to the growing mithun for improved rumen ecology, nutrient utilization and thus better performance under stall fed system.     

Structure of the membrane protein FhaC: a member of the Omp85-TpsB transporter superfamily

In Gram-negative bacteria and eukaryotic organelles, beta-barrel proteins of the outer membrane protein 85-two-partner secretion B (Omp85-TpsB) superfamily are essential components of protein transport machineries. The TpsB transporter FhaC mediates the secretion of Bordetella pertussis filamentous hemagglutinin (FHA). We report the 3.15 A crystal structure of FhaC. The transporter comprises a 16-stranded beta barrel that is occluded by an N-terminal alpha helix and an extracellular loop and a periplasmic module composed of two aligned polypeptide-transport-associated (POTRA) domains. Functional data reveal that FHA binds to the POTRA 1 domain via its N-terminal domain and likely translocates the adhesin-repeated motifs in an extended hairpin conformation, with folding occurring at the cell surface. General features of the mechanism obtained here are likely to apply throughout the superfamily.     

Superacids

Superacids, although first referred to as early as 1927, were only extensively studied in the last decade. Acidities up to 10(12) times that of sulfuric acid have now been obtained. The extremely low nucleophilicity of the counterions in superacidic systems is especially useful for the preparation of stable, electron-deficient cations, particularly carbocations. Many of these cations, which were formerly detectable only in the gas phase, can now be studied in solution. Novel organic syntheses that are not possible in ordinary acidic media can also be achieved in superacids, including syntheses of economically important hydrocarbons. The unique ability of superacids to bring about hydrocarbon transformations, even to activate methane to undergo electrophilic oligocondensation, can open up new fields in chemistry.     

Amino acid profile of winged bean (Psophocarpus tetragonolobus (L.) DC): a rich source of vegetable protein

Twenty one cultivars of winged bean (17 of Indian origin and 4 exotic strains obtained from Sri Lanka) were cultivated on marginal (alkaline) soils in the sub-tropics and evaluated for their food value. Whereas the seeds showed wide variations in total protein content (38.1 to 45 per cent), the amino acid compositions were in close proximity to those of soybean. Nevertheless, some strains of winged bean registered higher levels of certain amino acids as compared to soybean.