Effect of media composition and explant type on the regeneration of eggplant (Solanum melongena L.)

Two as well as three way interactions of three eggplant genotypes, media compositions and explants (hypocotyl, cotyledon and leaf) showed significant differences for plant regeneration. Among three explants, hypocotyl induced highest percent callusing, but cotyledon showed best results for somatic embryogenesis on all the media compositions. For three way interactions, cotyledon of BSR-27 induced significantly highest somatic embryogenesis (94.47%) on Murashige and Skooge (MS) fortified with 1.5 mgl-1 indole butyric acid (IBA) + 1.0 mgl-1 6-benzyl aminopurine (BAP). However, hypocotyl of BR-16 was not able to induce somatic embryogenesis on MS media fortified with 1.5 mgl-1 IBA + 1.0 mgl-1 BAP. Moreover, the embryogenic callus from cotyledon of BSR-27 (72.24%) achieved highest plant regeneration from somatic embryos on MS supplemented with 2.5 mgl-1 BAP + 1.0 mgl-1kin + 0.2% activated charcoal. Therefore, the performance of cotyledon explant of BSR-27 is the best on MS fortified with 1.5 mgl-1 IBA + 1.0 mgl-1 BAP and 2.5 mgl-1 BAP + 1.0 mgl-1kin + 0.2% activated charcoal for somatic embryogenesis and plant regeneration, respectively.Keywords: Callus, somatic embryogenesis, hypocotyl, cotyledon, leafAfrican Journal of Biotechnology Vol. 12(8), pp. 860-86

Red rot resistant transgenic sugarcane developed through expression of β-1,3-glucanase gene.

Sugarcane (Saccharum spp.) is a commercially important crop, vulnerable to fungal disease red rot caused by Colletotrichum falcatum Went. The pathogen attacks sucrose accumulating parenchyma cells of cane stalk leading to severe losses in cane yield and sugar recovery. We report development of red rot resistant transgenic sugarcane through expression of β-1,3-glucanase gene from Trichoderma spp. The transgene integration and its expression were confirmed by quantitative reverse transcription-PCR in first clonal generation raised from T0 plants revealing up to 4.4-fold higher expression, in comparison to non-transgenic sugarcane. Bioassay of transgenic plants with two virulent C. falcatum pathotypes, Cf 08 and Cf 09 causing red rot disease demonstrated that some plants were resistant to Cf 08 and moderately resistant to Cf 09. The electron micrographs of sucrose storing stalk parenchyma cells from these plants displayed characteristic sucrose-filled cells inhibiting Cf 08 hyphae and lysis of Cf 09 hyphae; in contrast, the cells of susceptible plants were sucrose depleted and prone to both the pathotypes. The transgene expression was up-regulated (up to 2.0-fold in leaves and 5.0-fold in roots) after infection, as compared to before infection in resistant plants. The transgene was successfully transmitted to second clonal generation raised from resistant transgenic plants. β-1,3-glucanase protein structural model revealed that active sites Glutamate 628 and Aspartate 569 of the catalytic domain acted as proton donor and nucleophile having role in cleaving β-1,3-glycosidic bonds and pathogen hyphal lysis

Norfloxacin and cisapride combination decreases the incidence of spontaneous bacterial peritonitis in cirrhotic ascites

Background: Spontaneous bacterial peritonitis (SBP) is a serious complication of cirrhosis with ascites, having high recurrence despite antibiotic prophylaxis. Small bowel dysmotility and bacterial overgrowth have been documented to be related to SBP. The purpose of the present paper was (i) to study whether addition of a prokinetic agent to norfloxacin ameliorates the development of SBP in high-risk patients; and (ii) to identify risk factors for SBP development. Methods: A prospective, single blinded, randomized controlled trial was conducted in high-risk cirrhotic patients with ascites who had either recovered from an episode of SBP or who had low ascitic fluid protein. Norfloxacin 400 mg once daily (group I) or norfloxacin 400 mg once daily with cisapride 20 mg twice a day (group II) was given and occurrence of side-effects of therapy and mortality were recorded. Results: Of the 94 patients, 48 (51%) were in group I, and 46 (49%) in group II. The actuarial probability of developing SBP at 12 month in group I was 56.8% and in group II, 21.7% (P = 0.026). Treatment failure was observed in five patients (10%) in group I and none in group II (P = 0.003). The actuarial probability of death at 18 months was 20.6% in group I and 6.2% in group II (P = 0.1). Low serum albumin, low ascitic fluid protein and alcoholic cirrhosis were related to development of SBP (P < 0.05). Additionally, low serum albumin (2.8 g/dL), gastrointestinal bleeding, alcoholic cirrhosis and low ascitic fluid protein were significantly associated with multiple occurrences of SBP. Conclusions: Prophylaxis with norfloxacin and cisapride significantly reduces the incidence of SBP in high-risk cirrhosis patients; low serum albumin, low ascitic fluid protein and alcoholic cirrhosis predispose to the development of SBP in high-risk cirrhosis patients; and low ascitic fluid protein should also be considered as a risk factor for the development of SBP requiring prophylaxis

Bioassay for red rot incidence.

<p><b>A</b> NT plant inoculated with Cf 08 showing susceptibility. <b>B</b> SN10-12 inoculated with Cf 08 revealing resistance. <b>C</b> SN10-12 ratoon inoculated with Cf 09 displaying moderate resistance. <b>D</b> NT plant inoculated with Cf 09 demonstrating high susceptibility.</p

Structural model showing protein-ligand interaction.

<p>β-1,3-glucanase protein (GenBank Accession No. AIC32930) docked with D-glucose.</p

Scanning electron micrographs of stalk sections from CG₁ transgenic and NT plants following inoculation with <i>C</i>. <i>falcatum</i>.

<p><b>A</b> Sucrose-filled parenchyma cells of non-inoculated NT plant (control). Arrow indicates the characteristic turgid cell. Bar represents 20 μm. <b>B</b> Presence of normal Cf 09 fungal hyphae in parenchyma cells of susceptible NT plant. Arrow indicates the sucrose depleted cell. Bar represents 20 μm. <b>C</b> Parenchyma cells of transgenic plant moderately resistant to Cf 09. Arrow indicates abnormal fungal hypha and amorphous debris. Bar represents 100 μm. <b>D</b> Sucrose-filled parenchyma cells of transgenic plant resistant to Cf 08 showing absence of hyphae. Arrow indicates the turgid cell. Bar represents 100 μm.</p

Red rot resistant transgenic sugarcane developed through expression of <i>β-1</i>,<i>3-glucanase</i> gene

<div><p>Sugarcane (<i>Saccharum</i> spp.) is a commercially important crop, vulnerable to fungal disease red rot caused by <i>Colletotrichum falcatum</i> Went. The pathogen attacks sucrose accumulating parenchyma cells of cane stalk leading to severe losses in cane yield and sugar recovery. We report development of red rot resistant transgenic sugarcane through expression of <i>β-1</i>,<i>3-glucanase</i> gene from <i>Trichoderma</i> spp. The transgene integration and its expression were confirmed by quantitative reverse transcription-PCR in first clonal generation raised from T₀ plants revealing up to 4.4-fold higher expression, in comparison to non-transgenic sugarcane. Bioassay of transgenic plants with two virulent <i>C</i>. <i>falcatum</i> pathotypes, Cf 08 and Cf 09 causing red rot disease demonstrated that some plants were resistant to Cf 08 and moderately resistant to Cf 09. The electron micrographs of sucrose storing stalk parenchyma cells from these plants displayed characteristic sucrose-filled cells inhibiting Cf 08 hyphae and lysis of Cf 09 hyphae; in contrast, the cells of susceptible plants were sucrose depleted and prone to both the pathotypes. The transgene expression was up-regulated (up to 2.0-fold in leaves and 5.0-fold in roots) after infection, as compared to before infection in resistant plants. The transgene was successfully transmitted to second clonal generation raised from resistant transgenic plants. β-1,3-glucanase protein structural model revealed that active sites Glutamate 628 and Aspartate 569 of the catalytic domain acted as proton donor and nucleophile having role in cleaving β-1,3-glycosidic bonds and pathogen hyphal lysis.</p></div

Comparison of relative <i>β-1</i>,<i>3-glucanase</i> expression in leaves and roots of CG₁ transgenic plants before and after inoculation with Cf 09 pathotype.

<p>Comparison of relative <i>β-1</i>,<i>3-glucanase</i> expression in leaves and roots of CG₁ transgenic plants before and after inoculation with Cf 09 pathotype.</p