Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: gross,microscopic and scanning electron microscopic observations

The efficacy of carbon fibres and plasma-preserved tendon allografts for gap repair in the superficial digital flexor tendon in the mid-metatarsal region was evaluated in 12 crossbred calves. Experimental tenectomies were performed, followed by implantation of carbon fibres in group I (12 legs) and plasma-preserved tendon allografts in group II (12 legs). Gross observations in group I showed filling of the defect with granulation tissue with more vascularity on day 7, which was less prominent at day 14. On day 30, the neotendon formed was slightly thicker and comparable to normal tendon in appearance and texture. On day 90, it exhibited all the characteristics of a fully developed tendon. Whereas, in group II increased vascularity at the site and encapsulation of the graft with connective tissue in early periods was observed. The gap between graft and host was filled with fibrous connective tissue. Peritendinous adhesions were maximum on day 7 which were gradually reduced in both groups. Microscopically, an acute inflammatory reaction in the periphery of carbon fibres was observed on day 7. Immature fibroblasts were arranged in a haphazard pattern at this stage. By day 14, numerous newly formed capillaries and comparatively more mature fibroblasts were present in between and around the carbon fibres which were aligning parallel to the longitudinal axis of the tendon. By day 30 the healing tissue exhibited longitudinal orientation of collagen fibres and was at a more advance stage of maturation. By day 90, the neotendon formed simulated the picture of normal tendon. In the grafted tendon group, there was normal healing tissue at the functional sites between host and grafted tendon. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. The connective tissue had invaded the graft to a variable distance and there was resorption of graft which was replaced by newly formed connective tissue on day 90. Scanning electron microscopic observation revealed formation of neotendon between carbon fibre strands, resulting in thickening of the implant. In later stages parallel collagen fibres resembling normal tendon were observed in both groups.     

Polymerase chain reaction amplification of 16S-23S spacer region for rapid identification of Salmonella serovars

Polymerase chain reaction (PCR) was used to amplify the spacer regions between the 16S and 23S genes of rRNA genetic loci of Salmonella serovars for their rapid identification. These genetic loci revealed a significant level of polymorphism in length across the species/serovar lines. When the 16S-23S spacer region amplification products were subjected to agarose electrophoresis, the patterns observed could be used to distinguish all the serovars of Salmonella tested. Unique elements obtained in amplification products were mostly clustered at serovar level, although certain genus-specific patterns were also observed. On the basis of the results obtained, the amplification of 16S-23S ribosomal spacer region could suitably be used in a PCR-based identification method for Salmonella serovars.     

Measurement of within and between population genetic variability in quails

1. To detect polymorphism in various quail lines, Randomly Amplified Polymorphic DNA (RAPD) markers were tested and were found to be effective. 2. Twenty decamer primers were selected at random and tested, and 6 of these generated distinct polymorphic patterns between the quail lines. 3. Out of a total of 60 bands amplified using 6 selected primers, 19 (31.7%) were found to be polymorphic. 4. Genetic similarity within the lines ranged from 0.726 in HBW to 0.836 in KLQ. 5. Genetic similarity estimates between the populations ranged from 0.709 to 0.808.     

IBDV-induced bursal T lymphocytes inhibit mitogenic response of normal splenocytes

We examined the suppressive activity of bursal T cells induced by infectious bursal disease virus (IBDV) in inbred (15x7) and outbred commercial specific-pathogen-free (SPF) chickens. The suppressive activity was measured by the ability of bursal and splenic T cells from IBDV-infected chickens to inhibit mitogenic responses of normal splenocytes. The bursacytes but not the splenocytes of IBDV-infected chickens inhibited the mitogenic responses of normal splenocytes. The mitogenic inhibition by the bursacytes of IBDV-infected chickens was dose-dependent. The suppression was observed both in inbred and non-inbred chickens, and thus, was non MHC-restricted. Cell-sorting experiments revealed that both CD4(+) and CD8(+) cells from the bursa of IBDV-infected chickens, as well as cell-culture supernatants conditioned by these cells, mediated suppression. Suppressor T (Ts) cells may therefore be involved in the immunosuppression induced by IBDV.     

Subcutaneous pharmacokinetics and dosage regimen of cefotaxime in buffalo calves (Bubalus bubalis)

The pharmacokinetics and dosage regimen of cefotaxime following its single subcutaneous administration (10 mg/kg) were investigated in buffalo calves. Plasma and urine samples were collected over 10 and 24 h post administration, respectively. Cefotaxime in plasma and urine was estimated by microbiological assay technique using E. coli as test organism. The pharmacokinetic profiles fitted one-compartment open model. The peak plasma levels of cefotaxime were 6.48 ± 0.52 µg/ml at 30 min and the drug was detected upto 10 h. The absorption half-life and elimination half-life were 0.173 ± 0.033 h and 1.77 ± 0.02 h, respectively. The apparent volume of distribution and total body clearance were 1.17 ± 0.10 l/kg and 0.45 ± 0.03 l/kg/h, respectively. The urinary excretion of cefotaxime in 24 h, was 5.36 ± 1.19 percent of total administrated dose. A satisfactory subcutaneous dosage regimen for cefotaxime in buffalo calves would be 13 mg/kg repeated at 12 h intervals.     

Hybridization and in vitro culture of an orchid hybrid Ascocenda ‘Kangla’

The present study focuses on hybridization program involving two species belonging to two different vandaceous genera, viz., Ascocentrum ampullaceum (Roxb.) Schltr. var. auranticum, a narrow endemic orchid of Manipur and Vanda coerulea Griff., an endangered orchid of Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), to synthesize the primary hybrid genus with intermediate and improved characters in the F₁ generation. Observations on the crossability in the present bigeneric cross between V. coerulea and A. auranticum had been achieved with 60% success when V. coerulea was taken as female parent. Murashige and Skoog (MS) basal medium at half-strength was effective for the development of the hybrid seedlings of V. coerulea × A. auranticum followed by Vacin and Went (VW) and Knudson C (KC) media. The best response of seedling growth was observed on MS medium at half-strength supplemented with 2.3 μM kinetin + 0.5 μM α-naphthalene acetic acid with maximum shoot height (2.7 cm), leaf number (4.6) and root number (4.1) after 150 days of inoculation. The survival percentage and growth performance of the seedlings were found to be higher (80% survival) in potting substrate consisting of brick:charcoal in the ratio 2:1 mulched with moss (Sphagnum sp.) than in potting substrate consisting of brick:charcoal:tree fern in the ratio 2:1:1. The first flowering was observed in the hybrid seedlings of V. coerulea × A. auranticum after 2 years of transfer to the ex vitro environment. Morphologically, the flowers differed from that of the parents clearly showing the success of the hybridization experiment. Registration of the hybrid has been made with the Royal Horticultural Society with the nomenclature Ascocenda ‘Kangla’ (No. T128725).     

Relationship between light,fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.)

A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g⁻¹ fresh tissue weight) and that of Ca was lower (0.098 mg g⁻¹ fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it.     

Bioinformatically mined simple sequence repeats in UniGene of Citrus sinensis

Characterization of microsatellites is extremely important for the development of molecular markers. Here, we present the detection and abundance of microsatellites or simple sequence repeats (SSRs) in UniGene sequences of Citrus sinensis. A total of 427 SSRs were mined in 8786 UniGene sequences downloaded from National Center for Biotechnology Information (NCBI). Depending on the repeat units, the length of SSRs ranged from 14 to 21 for mono-, 14 to 48 for di-, 18 to 48 for tri-, 24 to 40 for tetra- and 42 bp for hexa-nucleotide repeats. Average density of SSRs (1SSR/12.92 kb of 5518.71 kb sequences mined) suggests that only 4.43% of sequences contained SSRs. Di-nucleotide repeats were most frequent repeat type (49.41%) followed by tri-nucleotide repeats (41.45%). An attempt was made to design primer pairs for 427 identified SSRs but these were found only for 216 sequences. The positions of SSRs with respect to open reading frame (ORF) detected and annotation of sequences containing SSRs were also carried out to assign function to each of the sequences.     

Effect of tester on combining ability estimates of maize germplasm complexes

Eight maize complexes and varieties representing high and low yield levels were tested for their suitability as top cross testers by comparing the performance of the crosses in relation to the combining ability of the parents estimated by diallel analysis. The discriminating ability of the testers was compared by Schumann and Bradley test. In both cases the results clearly showed that the low performing testers were better and more reliable than the high performing complexes. The utility of per se performance as an indication of general combining ability of the complexes has been discussed.     

Assessment of clonal fidelity of micropropagated gerbera plants by ISSR markers

True-to-type clonal fidelity is one of the most important pre-requisites in micropropagation of crop species. Genetic fidelity of in vitro raised 45 plants of gerbera (Gerbera jamesonii Bolus) derived from three different explants, viz., capitulum, leaf and shoot tips, was assessed by 32 ISSR markers, for their genetic stability. Out of 32 ISSR markers, 15 markers produced clear, distinct and scorable bands with an average of 5.47 bands per marker. The markers designed from AG motif amplified more number of bands. The markers anchored at 3′ ends produced high number of consistent bands than unanchored markers. Fifteen ISSR markers generated a total of 3773 bands, out of which 3770 were monomorphic among all the clones. The Jaccard's similarity coefficient revealed that out of 45 clones derived from different explants, 44 were grouped into a single large cluster alongwith the mother plant with a similarity coefficient value of 1.00, whereas one clone (C38) remained ungrouped. The clones derived from capitulum and shoot tip explants did not show any genetic variation, whereas, one of the leaf-derived clones exhibited some degree of variation.