Scaffolds formed via the non-equilibrium supramolecular assembly of the synergistic ECM peptides RGD and PHSRN demonstrate improved cell attachment in 3D

Self-assembling peptides (SAPs) are a relatively new class of low molecular weight gelators which immobilize their solvent through the spontaneous formation of (fibrillar) nanoarchitectures. As peptides are derived from proteins, these hydrogels are ideal for use as biocompatible scaffolds for regenerative medicine. Importantly, due to the propensity of peptide sequences to act as signals in nature, they are easily functionalized to be cell instructive via the inclusion of bioactive epitopes. In nature, the fibronectin peptide sequence, arginine-glycine-aspartic acid (RGD) synergistically promotes the integrin α5β1mediated cell adhesion with another epitope, proline-histidine-serine-arginine-asparagine (PHSRN); however most functionalization strategies focus on RGD alone. Here, for the first time, we discuss the biomimetic inclusion of both these sequences within a self-assembled minimalistic peptide hydrogel. Here, based on our work with Fmoc-FRGDF (N-flourenylmethyloxycarbonyl phenylalanine-arginine-glycine-aspartic acid-phenylalanine), we show it is possible to present two epitopes simultaneously via the assembly of the epitopes by the coassembly of two SAPs, and compare this to the effectiveness of the signals in a single peptide; Fmoc-FRGDF: Fmoc-PHSRN (N-flourenylmethyloxycarbonyl-proline-histidine-serine-arginine-asparagine) and Fmoc-FRGDFPHSRN (N-flourenylmethyloxycarbonyl-phenylalanine-arginine-glycine-asparticacidphenylalanine- proline-histidine-serine-arginine-asparagine). We show both produced self-supporting hydrogel underpinned by entangled nanofibrils, however, the stiffness of coassembled hydrogel was over two orders of magnitude higher than either Fmoc-FRGDF or Fmoc-FRGDFPHSRN alone. In-vitro three-dimensional cell culture of human mammary fibroblasts on the hydrogel mixed peptide showed dramatically improved adhesion, spreading and proliferation over Fmoc-FRGDF. However, the long peptide did not provide effective cell attachment. The results demonstrated the selective synergy effect of PHSRN with RGD is an effective way to augment the robustness and functionality of self-assembled bioscaffolds

Evaluation of Plant Extracts Against Rice Blast Disease Caused by Pyricularia grisea

This study was carried out to determine the effect of plant extracts such as Siam weed, Eucalyptus, Swallow-wort, Neem, Lemongrass, Basil, Oleander and Golden trumpet on rice blast disease fungus Pyricularia grisea in vitro and in vivo. Percentages of disease control for rice blast with different plant extract spraying times (2 days before inoculation, 2 days after inoculation and after symptom appearance, i.e. 5 to 7 days after inoculation) were compared to find out the most effective spraying time. The experiments were conducted at the Department of Plant Pathology during May 2015 to August 2016. Antifungal activities of different plant extracts were evaluated on mycelial growth and spore germination using poison food technique and five effective plant extracts were selected for the next experiment. The results indicated all the tested plant extracts had antifungal effect with inhibition percent (10% - 39%) on mycelial growth and spore germination (67% - 88%). Among the extracts, Siam weed showed the maximum inhibition percent on both mycelial growth and spore germination followed by Eucalyptus, Swallow-wort and Neem extracts. In the greenhouse test, the test variety Shwe Thwe Yin was used to evaluate the effect of five selected plant extracts at different spraying times on rice blast disease by inoculating the plants at 21 days after sowing. The results indicated that Siam weed extract gave the higher disease control percentage (36%) compared with other treatments such as Swallow-wort (32%) and Eucalyptus (31%) at 11 days after inoculation. Spraying of plant extracts at 2 days before inoculation showed the highest disease control in comparison to other two spraying times

Characterization of Ralstonia solanacearum isolates in Myanmar

Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating diseases in economically important crops in the world. It is also important disease of solanaceous crops in Myanmar. The objective of this study was to identify the pathogenic isolates from d ifferent hosts and to characterize their race, biovar and phylotype levels. The disease collection was carried out in Shan State which is highland region (Kalaw, Heho), Mandalay Region (PyinOolwin and NyaungOo) and Naypyidaw Region (Yezin) which are relatively lowland areas during October 2012 and April 2013. Isolation was made on selective med ia (Tetrazolium chloride med ia) and identified as R. solanacearum based on morphological, pathological and biochemical properties and polymerase chain reaction (PCR) by using the species-specific primers. Total 32 isolates (14 potato isolates from Shan State, six pepper isolates, six tomato isolates and two eggplant isolates from Naypyidaw Region and four tomato isolates from Mandalay Region) were examined and all isolates tested were amplified R. solanacearum specific band (281 bp) by PCR. All tomato, eggplant and pepper strains belonged to race I biovar 3. Potato strains isolated from Heho area were race 3 biovar 2 and race I biovar 3. At Heho area, 33% of the tested strains belonged to race 3 biovar 2. Furthennore, multi plex PCR was conducted for the discrimination of phylotypes. Race I biovar 3 strains and race 3 biovar 2 strains belonged to phylotype I and phylotype II, respectively. This is the first report of identification and characterization of Myanmar R. solanacearum strains to race, biovar and phylotype

New Record on the Occurrence of Cyst Nematode, Heterodera cajani Koshy, 1967 on Sesame, Sesamum indicum in Myanmar

Sesame, Sesamum indicum L. occupies for nearly half of the area sown to oilseed crops in Myanmar. It is cultivated for domestic consumption and export. During 2003, sesame cultivars, Sinyadnar3, Sinyadanar5, Magway7/9 and Khwaylayni grown in Oilseed Crop Research Farm, Department of Agricultural .Research, Magway were found to be heavily infected with Heterodera cyst nematodes. In 2004, cysts were also found from the soil samples collected from the previously infested plots. Infested field showed patches in which the plants were stunted, chlorotic, and caused wilting. When the infected plants were uprooted, curving of tap root, and red-girdling and dark browning of lateral and tap roots were observed. Lemon-shaped cysts were found attaching to the root surface. Young females were white or creamy colour whereas old cysts with eggs were tan colour. A few bullae were found on the posterior portion of the female. Larvae were vermiform with elongate conoid tail. Males were cylindrical or elongated with short tail without bursa. According to the morphological characters of the nematode and disease symptoms of sesame, the nematode was supposed to be identified as Heterodera cajani. There was no report o cyst nematode, Heterodera spp. in Myanmar. The present finding, the occurrence of Heterodera cajani on sesamum, is the first record of Heterodera spp. in Myanmar

Evaluation of Resistance in Rice Plants to Myanmar Isolates of Xanthomonas oryzae pv. oryzae

To obtain genetic resources of resistance to bacterial leaf blight of rice caused by Xanthomonas oryzae pv. oryzae in Myanmar, 40 Myanmar rice varieties, 10 international differentials of near isogenic lines and 17 varieties of pyramided lines were tested for the resistance to three different pathotypes isolated in Myanmar. The bacterial isolate used were MKM13 (belonging to predominant race in Myanmar and showing wide range of pathogenicity), M 3-1 (showing intermediate range of pathogenicity) and MKM39 (belonging to rare race in Myanmar and showing narrow range of pathogenicity). The fully developed leaves at maximum tillering stage were used for inoculation of each isolate. Three weeks after the inoculation scoring was made according to the lesion length. The reaction was considered as S (susceptible) when the lesion length was more than 5 cm, while considered as R (resistant) when it was 5 cm below. In the inoculation test using international differentials of near isogenic lines, the resistance genes, X_{a21} and X_{a3}, would be effective resistant resources to the bacterial blight diseases in Myanmar. Although bacterial isolate MKM39 was avirulent to IR24, some Myanmar varieties were susceptible to this isolate. Rice varieties cultivated in Myanmar were classified into four groups based on their reactions to three Myanmar bacterial isolates. Group Ⅰ contained one variety was resistant to all the three isolates of pv. oryzae and group Ⅱ contained 14 varieties was susceptible. Group Ⅲ contained 23 varieties resistant to bacterial isolate MKM39 but susceptible to MKM13 and M3-1. Group Ⅳ contained two varieties was susceptible to bacterial isolate MKM13 but resistant to M3-1 and MKM39. Furthermore, gene combinations X_{a3}＋X_{a7}, X_{a3}＋ X_{a10}, X_{a4}＋x_{a5} and X_{a4}＋x_{a5}＋X_{a13}＋X_{a21} conferred a broad spectrum of resistance to all three Myanmar isolates evaluated, supporting the strategy of pyramiding appropriate resistance genes

Evaluation of Resistance in Rice Plants to Myanmar Isolates of Xanthomonas oryzae pv. oryzae

To obtain genetic resources of resistance to bacterial leaf blight of rice caused by Xanthomonas oryzae pv. oryzae in Myanmar, 40 Myanmar rice varieties, 10 international differentials of near isogenic lines and 17 varieties of pyramided lines were tested for the resistance to three different pathotypes isolated in Myanmar. The bacterial isolate used were MKM13 (belonging to predominant race in Myanmar and showing wide range of pathogenicity), M 3-1 (showing intermediate range of pathogenicity) and MKM39 (belonging to rare race in Myanmar and showing narrow range of pathogenicity). The fully developed leaves at maximum tillering stage were used for inoculation of each isolate. Three weeks after the inoculation scoring was made according to the lesion length. The reaction was considered as S (susceptible) when the lesion length was more than 5 cm, while considered as R (resistant) when it was 5 cm below. In the inoculation test using international differentials of near isogenic lines, the resistance genes, X_{a21} and X_{a3}, would be effective resistant resources to the bacterial blight diseases in Myanmar. Although bacterial isolate MKM39 was avirulent to IR24, some Myanmar varieties were susceptible to this isolate. Rice varieties cultivated in Myanmar were classified into four groups based on their reactions to three Myanmar bacterial isolates. Group Ⅰ contained one variety was resistant to all the three isolates of pv. oryzae and group Ⅱ contained 14 varieties was susceptible. Group Ⅲ contained 23 varieties resistant to bacterial isolate MKM39 but susceptible to MKM13 and M3-1. Group Ⅳ contained two varieties was susceptible to bacterial isolate MKM13 but resistant to M3-1 and MKM39. Furthermore, gene combinations X_{a3}＋X_{a7}, X_{a3}＋ X_{a10}, X_{a4}＋x_{a5} and X_{a4}＋x_{a5}＋X_{a13}＋X_{a21} conferred a broad spectrum of resistance to all three Myanmar isolates evaluated, supporting the strategy of pyramiding appropriate resistance genes