1-Methylcyclopropene (1-MCP) has been found to inhibit ethylene action and thus it can delay the fruit ripening process. The effects of 1-MCP (90 ppb for 12 h) on softening related changes were determined through physiological changes, fruit firmness and activities of the cell wall degrading enzymes including α-galactosidase, β-galactosidase, pectin methylesterase (PME) and xylanase during ripening in papaya (Carica papaya L. cv Sekaki). In this study, fruits were treated with 90 ppb concentration of 1-MCP gaseous vapors for 12 h in airtight container maintained at 28oC. After the treatment fruits were placed at ambient temperature (28oC). Papaya treated with 1-MCP experienced a significant delayed in skin color development, weight loss and reduced firmness loss compared with the fruit without 1-MCP treatment. As softening progressed, activity of the cell wall degrading enzymes in fruit without 1-MCP treatment increased significantly coincident with a rapid decline in fruit firmness. With 1-MCP application, fruit experienced a delay in activity of cell wall degrading enzymes but continued to increase until later stage of ripening. Thus it may be suggested that 1-MCP treatment may aid in delaying softening-related process and thereby extended the postharvest life and maintained the quality of the ‘Sekaki’ papaya fruit.
Kapsaisinoid merupakan alkaloid yang memberikan ciri kepedasan pada cili serta khusus pada genus Capsicum. Sebatian kapsaisinoid terdiri daripada dua komponen utama iaitu kapsaisin dan dihidrokapsaisin. Dalam kajian ini, pengklonan cDNA Kapsaisin sintase (Cs) telah berjaya dilakukan menerusi kaedah transkripsi berbalik PCR (RT-PCR) dan klon cDNA tersebut dinamakan CUKMCS yang bersaiz 981 pb. Pencarian homologi menggunakan program blastx dan blastp yang terdapat pada pangkalan data NCBI mendapati CUKMCS mempunyai persamaan yang sangat tinggi terhadap Cs pada Capsicum frutescens, Capsicum annuum dan Capsicum chacoense. Saiz ramalan protein CUKMCS diangggarkan sekitar 36 kDa. Penentuan pengekspresan transkrip Cs pada 5 tisu yang berbeza mendapati transkrip dikesan pada tisu plasenta, mesokarp dan biji manakala tiada transkrip Cs dikesan pada daun dan akar
Kajian ke atas kaedah inokulasi eksplan menggunakan vektor penandaan tanpa promoter, pCAMDIN ke atas tomato varieti tempatan MT1, bagi tujuan mutagenesis penyelitan T-DNA menggunakan kaedah infiltrasi agro telah dijalankan. Bahagian daun muda disuntik dengan larutan yang mengandungi Agrobacterium tumefaciens, 100 mg/l Str, 50 mg/l Kan, 10mM MES dan 100 μM Acetosyringone. Infiltrasi dilakukan ke atas sampel daun dengan menggunakan medium LB, bahagian permukaan daun dilukakan dan infiltrasi agro dilakukan ke atas sampel daun pokok tomato yang berada di dalam rumah kaca. Tisu yang diinfiltrasi tidak mengalami kecederaan dan kekal hijau selepas 5 hari. Infiltrasi yang
mudah dilakukan dan pengekspresan transien GUS yang dapat dicerap berlaku pada sampel yang dianalisa adalah antara kebaikan kaedah ini. Seterusnya, fragmen gen gus telah berjaya diamplifikasi. Kejayaan integrasi gen gus ke dalam tomato juga dapat dilihat melalui penghibridan Southern. Berdasarkan keputusan ini, dapat dicadangkan bahawa penyelitan transgen daripada vektor rekombinan pCAMDIN telah berlaku dalam genom tomato.
Agrobacterium-mediated transformation of indica rice is undoubtedly a challenging task due to the rice recalcitrant nature to transformation process. Therefore, optimization of the transformation protocol is important for specific indica rice cultivar to ensure effectiveness of the transformation. In this study, crucial parameters affecting Agrobacteriummediated transformation were optimized to obtain transgenic rice of local rice cultivar (indica MR219). Embryogenic calli were chosen for inoculation with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector pH2GW7ABP57 containing gene of interest, Auxin binding protein 57 (Abp57). The parameters that have been optimized were the immersion time, co-cultivation period, acetosyringone concentration and co-cultivation temperature. A total of four days co-cultivation period and 30 min immersion of embryogenic callus are optimum for the transformation of MR219 with transformation efficiency of 26.4% and 16.0%, respectively. Acetosyringone at 200 μM and co-cultivation at 28°C also gave the highest transformation efficiency (14.4 and 18.4%, respectively). Meanwhile, inclusion of 20 g/L maltose+20 g/L sorbitol into the regeneration media has significantly improve the transformed somatic embryos growth and increase the regeneration efficiency up to 40.0%. The results of polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) indicated that the transgene was successfully integrated and overexpressed in transgenic rice of MR219. In conclusion, significant improvement in transformation efficiency for rice cv. MR219 has been obtained by using the optimised protocol for transformation and regeneration developed in this study.
We investigated the central mass distribution of the luminous infrared galaxy NGC 3256 at a distance of 35 Mpc by using
CO(1-0) observations of the Atacama Large Millimeter and sub-millimeter Array (ALMA) and near-IR data of the Two
Micron Sky Survey (2MASS). We found that there is a huge amount of invisible dynamical mass (4.48 × 1010 ) in the
central region of the galaxy. The invisible mass is likely caused by some dark matter, which might have a cuspy dark
matter profile. We note that this dark matter is difficult to explain with the conventional Modified Newtonian Dynamics
(MOND) model, which is only applicable at a low acceleration regime, whereas the acceleration at the central region
of the galaxy is relatively strong. Therefore, this discovery might pose a challenge to the conventional MOND models.
Tiger's Milk mushroom (Lignosus rhinocerus) is a highly priced medicinal mushroom utilized in traditional medicine to treat various diseases. However, due to insufficient wild L. rhinocerus, submerged culture conditions and nutritional requirements for the production of mycelial biomass and exopolysaccharide (EPs) from L. rhinocerus were studied using one-factor-at-a-time and orthogonal matrix method in shake flask culture. The optimal pH and temperature for ideal production of mycelial biomass and EPS were found to be at pH6 and 25°C, respectively. The optimal compositions for mycelial biomass production were 80 gIL of glucose, 4 gIL of potassium nitrate, 0.4 gIL of FeSO4.7H20 and 0.1 gIL of CaCl2. Subsequently, the optimal compositions for EPS production were 80 gIL of glucose, 4 gIL of potassium nitrate, 1.4 gIL of FeSO4.7H20 and 1.1 gIL of CaCl2. The maximum mycelial biomass and EPS concentrations achieved in a 1.5 L stirred-tank bioreactor were 6.3788 gIL and 12 gIL, respectively. Mycelial biomass production was about 3 times higher than that at the basal medium. However, EPS production indicated no significant difference at the basal medium. In addition, the concentrations for a-amylase, [3-amylase, cellulase and invertase in optimal medium were 2 .87 , 1 .07 , 3.0 and 3.0 mglmL, respectively. Current findings suggest that the production of mycelial biomass and EPS of L. rhinocerus can be enhanced dramatically by controlling the culture conditions and modifying the medium's composition.
F-box proteins containing variable C-terminal domains make an essential part of SKP1-Cullin-Ring box-F box (SCF)
complex. SCF complex catalyzes the final step to link the ubiquitin tag with the target protein, destined for degradation,
through F-box protein that confer overall substrate specificity to the complex. In this study, we analyzed the role of
At2g02870, a Kelch containing F-box protein from Arabidopsis thaliana, by using reverse genetics strategy. At2g02870
loss of function mutant lines (at2g02870) were analyzed and compared with wild type plants for the expression of genes
and products of hydroperoxide lyase (HPL) branch of oxylipin pathway. We found that the at2g02870 plants have enhanced
expression of HPL pathway genes and produce more green leaf volatiles (GLV) than the wild type plants. Our results
suggested that the gene is involved in the regulation of HPL pathway, possibly through the degradation of enzymes or/
and the regulatory factors of the pathway.
Gen Proteolisis 6 (PRT6) merupakan gen yang memainkan peranan penting dalam tapak jalan N-end rule dan berfungsi
sebagai enzim E3 ligase. PRT6 berperanan dalam pengenalan protein sasaran bagi proses degradasi. Objektif utama kajian
ini adalah untuk mentransformasi konstruk RNAi PRT6 ke dalam tomato berperantarakan Agrobacterium tumefaciens.
Ini bertujuan untuk memahami peranan tapak jalan N-end rule semasa proses pemasakan buah. Beberapa faktor yang
memberi kesan kepada transformasi seperti masa ko-penanaman dan juga kepekatan antibiotik yang digunakan telah
dioptimumkan. Keputusan kajian menunjukkan pengeraman kotiledon selama 48 jam pada medium ko-penanaman dapat
meningkatkan penghasilan kalus sebanyak 61% manakala penggunaan 500 mg/L antibiotik karbenisilin dalam medium
regenerasi pucuk dapat mengurangkan kontaminasi A. tumefaciens sehingga 5.2%. Selain itu, strain A. tumefaciens
C58 merupakan strain A. tumefaciens yang paling sesuai digunakan sebagai perantara dalam kajian ini. Tindak balas
berantai polimerase (PCR) telah dijalankan pada pucuk yang terhasil untuk mengesahkan integrasi fragmen PRT6 ke dalam
genom tomato. Berdasarkan analisis PCR, kesemua tujuh pucuk putatif transgenik adalah merupakan transforman positif.
Delta 6-asid lemak desaturase dan delta 12-asid lemak desaturase merupakan enzim yang diperlukan bagi langkah desaturasi semasa proses biosintesis asid gamma-linolenik (GLA) oleh kulat oleaginus. Objektif kajian ini ialah untuk menganalisis profil pengekspresan gen mengekod enzim delta 6-asid lemak desaturase (des6) dan delta 12-asid lemak desaturase (des12) kulat oleaginus Cunninghamella bainieri semasa penghasilan GLA. Jujukan gen separa bersaiz 1372 pb bagi des6 dan 1008 pb bagi des12 telah dipencil daripada C. bainieri. Analisis pengekspresan gen menggunakan kaedah tindak balas berantai polimerase kuantitatif masa sebenar (RT-qPCR) menunjukkan perubahan kadar pengekspresan des6 adalah lebih tinggi berbanding kadar pengekspresan des12 semasa penghasilan GLA. Pengekspresan des6 adalah tertinggi selepas 24 jam dikultur dalam medium penghasilan GLA. Namun, kadar pengekspresannya menurun hingga jam ke-96 pertumbuhan tetapi meningkat semula pada jam ke-120. Bagi des12, kadar pengekspresannya adalah lebih sekata dengan pengekspresan tertinggi dikesan pada jam ke-120. Analisis penghasilan GLA menunjukkan jumlah GLA dalam sel berkolerasi dengan kadar pengekspresan des6. Hasil kajian mencadangkan bahawa aras pengekspresan des6 adalah penting dalam menentukan aras GLA dalam C. bainieri.
Kitin merupakan polisakarida struktur yang dapat dicurai oleh enzim kitinolisis kepada pelbagai terbitan yang boleh digunakan dalam bidang perubatan, pertanian dan rawatan air. Pengenalpastian dan pencirian gen-gen Trichoderma virens UKM1 mengekod enzim terlibat dalam pencuraian kitin krustasea telah dilakukan melalui penjanaan penanda jujukan terekspres (ESTs) dan analisis pengekspresan gen menggunakan mikroatur DNA. Sebanyak tiga perpustakaan cDNA T. virens UKM1 yang masing-masing diaruh oleh kitin, glukosamina dan kitosan telah dibina. Sejumlah 1536 klon cDNA telah dijujuk dan sebanyak 1033 ESTs berkualiti telah dijana. Seterusnya, perbezaan pengekspresan gen apabila pertumbuhan kulat diaruh dengan kehadiran kitin krustasea dan tanpa kitin pada hari ketiga dan kelima telah ditentukan. Sebanyak 1824 klon cDNA telah dititik ke atas slaid kaca dan dihibrid bersama dengan cDNA terlabel Cy3 atau Cy5 yang disintesis daripada mRNA yang dipencil daripada kulat yang ditumbuhkan dalam medium mengandungi kitin krustasea atau glukosa (kawalan). Sebanyak 91 dan 61 gen, masing-masing bagi hari ketiga dan kelima didapati terekspres melebihi dua gandaan apabila kulat menggunakan kitin krustasea sebagai sumber karbon. Beberapa gen mengekod kitinase seperti ech1 dan cht3 (endokitinase), nag1 (eksokitinase) dan nagB (glukosamina 6-P-deaminase) didapati terekspres dengan tinggi pada kedua-dua hari. Selain daripada itu, gen mengekod protein hidrofobin, protease serina dan beberapa protein hipotetik juga terekspres dengan tinggi dengan kehadiran kitin krustasea. Protein-protein ini dijangka memainkan peranan penting dalam membantu pencuraian kitin krustasea.