Mycorrhizal fungi Glomus spp. propagation in zeolite enriched with mycorrhiza helper bacteria for controlling nematode in coffee

Arbuscular mycorrhizal fungi (AMF) play a role in suppressing the nematode Pratylenchus coffeae. Mycorrhizal helper bacteria (MHB) can increase the effectiveness of AMF to control the diseases. The experimental purpose was to increase the spore population of AMF Glomus spp. in zeolite-based formulation inoculated with liquid consortia of Pseudomonas diminuta and Bacillus subtilis as MHB. The experimental design was a completely random design with six treatments consisted of 106, 107, 108, and 109 CFU/mL MHB liquid inoculants. The control treatments were water and 2% molasses. All treatments were replicated four times. A total of 300 mL/pot Liquid inoculant of MHB have been inoculated a three day before transplanting the maize seedling to the Zeolite inoculated with Glomus spp. in the pot. One month after MHB inoculation, Glomus formulation in Zeolite with different levels of MHB increased the degree of infection. Three months after MHB inoculation, spore content in Zeolite increased. The density of P. diminuta and B. subtilis in zeolite-based mycorrhizal inoculant increased at the end of the experiment. Liquid inoculant MHB contained 108 CFU/mL enhanced spora number fourth times compared to the control. This experiment suggests that P. diminuta and B. subtilis were effective to increase the spore density of AMF inoculant.

Asymmetric dynamic coupling promotes alternative evolutionary pathways in an enzyme dimer

The importance of dynamic factors in enzyme evolution is gaining recognition. Here we study how the evolution of a new enzymatic activity exploits conformational tinkering and demonstrate that conversion of a dimeric phosphotriesterase to an arylesterase in Pseudomonas diminuta is accompanied by structural divergence between the two subunits. Deviations in loop conformations increase with promiscuity, leading to functionally distinct states, while they decrease during specialisation for the new function. We show that opposite loop movements in the two subunits are due to a dynamic coupling with the dimer interface, the importance of which is also corroborated by the co-evolution of the loop and interface residues. These results illuminate how protein dynamics promotes conformational heterogeneity in a dimeric enzyme, leading to alternative evolutionary pathways for the emergence of a new function.

Identifikasi Bakteri dan Efektivitas Antibiotik dalam Pengencer untuk Mengontrol Pertumbuhan Bakteri pada Semen Sapi Friesian Holstein

This study was designed to investigate the presence of bacterial species in Friesian Holstein (FH) bovine semen at the time of collection, processing and to assess the efficacy of two types of antibiotics combinations; penicillin and streptomycin (PS) and gentamycin, tylosin, lincomycin and spectinomycin (GTLS) in semen extender on bacterial control and quality of semen. For this purpose, three experiments were conducted. In experiment 1, identification of bacterial content in fresh semen which collected from 5 bovine ejaculates. In experiment 2, identification of bacterial content in skimmilk-eggyolk extender which were prepared in artificial insemination center, Lembang, Bandung. In experiment 3, identification of bacterial content in frozen thawed semen. In the result, some of bacterial species were isolated from the bovine semen. The GTLS combination of antibiotics may be incorporated into a freezing extender or protocol without compromising the post-thawed semen quality of FH bull spermatozoa. Three types of bacteria were found in fresh semen; Klebsiella sp., Micrococcus sp., and Pediococcus sp.. Three types of bacteria were found in semen extender; Enterobacter cloacae, Pseudomonas diminuta and Serratia plymutica. Two types of bacteria were found in frozen semen; Enterobacter cloacae and Serratia plymutica. In conclusion, antibiotics PS and GTLS were effective for controlling the growth of bacteria in frozen semen.

Aplikasi Agens Hayati untuk Mengendalikan Hawar Daun Bakteri pada Produksi Benih Padi

<p align="center"><strong><em>ABSTRACT</em></strong></p><em>This experiment is a further development of several previous studies on the potential of Bacillus subtilis 5/B and Pseudomonas diminuta A6 (rhizobacteria), and Aeromonas sp. F112 (phyllobacteria) as biological agents. Research aimed to evaluate the application of biological agents to promote plant growth and to control bacterial leaf blight (BLB) disease in rice seed production. This research consisted of two experiments, the first was in the nursery while the second was in the field. The first experiment conducted in a completely randomized design with one factor (seed treatments) and three levels, i.e., control (untreated), matriconditioning + streptomycin sulphate 0.2% (BsM), biomatriconditioning + B. subtilis 5/B + P. diminuta A6 (BM). The second experiment was conducted in a randomized complete block design with one factor (biological agent aplication methods) and nine levels, i.e., control (untreated), matriconditioning + streptomycin sulphate 0.2% (BsM), biomatriconditioning + B. subtilis 5/B + P. diminuta A6 (BM), soaking of seedlings root with B. subtilis 5/B + P. diminuta A6 (RA), foliar spraying with Aeromonas sp. F112 (SD), BM + RA, BM + SD, RA + SD, BM + RA+ SD. The result showed that seed treatments significantly increased field emergence. Eventhough all treatments did not significantly affect plant growth, incidency and severity level of BLB disease, and yield components, biomatriconditioning showed a better improvement in yield components. The seeds produced from plants treated with the biological agents showed significantly higher vigor index than untreated and matriconditioning + streptomycin sulphate 0.2%. </em><br /><br /><em>Keywords: Aeromonas sp., Bacillus subtilis, biomatriconditioning, seed quality, Pseudomonas diminuta</em>

Responses of Potato (Solanum tuberosum) to Glomus sp. Combined with Pseudomonas diminuta at Different Rates of NPK Fertilizers

Conventional farming for potato production in Indonesia has been using NPK fertilizer at high application rates. Any adverse environmental effects that might arise trough this fertilizer use shall be avoided. Application of bioferrtilizer consisted of ArbuscularMycorrhizal Fungi (Glomus sp.) isolated from the potato farming area and Mycorrhizal Helper Bacteria (Pseudomonas diminuta) have been tested to reduce the use of NPK rates in the production of potato crops. The inoculant has been pot-cultured prior to its application on potato crops. The controlled-field site experiment, used the mixtures of spores of Glomus sp. and inoculant of Pseudomonas diminuta, applied at different rates of NPK fertilizer. Results of the experiment showed that the application of Glomus sp. and Pseudomonas diminuta reduced the use of NPK up to 50%, where the growth, nutrients uptake(N,P,K), and tubers of potato had similar effect to the highest recommendation rate of NPK fertilizer (being applied by the farmers). Findings from this experiment confirmed the evidences that application of AM fungi and mycorrhizal helper bacteria could reduce the use of chemical fertilizer which support sustainable farming system. Further step has been done to scale up the production of inoculants for the wider use by local farmers. Keywords:Glomus, Pseudomonas, mycorrhiza, potato, NPK fertilizer.

Peningkatan kemantapan agregat tanah mineral oleh bakteri penghasil eksopolisakarida Aggregate stability improvement of mineral soil by exopolysaccharide-producing bacteria

Summary Pseudomonas fluorescens PG7II.1, Flavobacterium sp. PG7II.2, and Pseudomonas diminuta PG7II.9 have a potential to produce exopolysaccharide which help the formation and stabilization of soil aggregate. These bacteria have been isolated from the rhizosphere of Saccharum officinarum. Exopolysaccharide production in ATCC 14 liquid medium with sucrose was higher than that obtained from glucose, lactose, and 4-hydroxyphenil acetic acid (4-HAA) as a carbon sources. Producing of exopolysaccharide from these bacteria were 8.04 (P. fluorescens PG7II.1), 2.0 (Flavo-bacterium sp. PG7II.2) and 1.82 mg/mL (P. diminuta PG7II.9). Aggregate Stability Index (ASI) of mineral soil material was 114 when inoculated by these isolates after 60 days incubation period at ambient temperature. The ASI value of inoculated mineral soil material significantly different with uninoculated. The optimum of bacterial suspension to increase aggregate stability of mineral soil material was 12.5% (v/w) consisted of 109 CFU per mL. Ringkasan Pseudomonas fluorescens PG7II.1, Flavobacterium sp. PG7II.2, dan Pseudomonas diminuta PG7II.9, memiliki potensi dalam menghasilkan eksopolisakarida untuk pem-bentukan dan kemantapan agregat tanah. Ketiga bakteri tersebut diisolasi dari rhizosfer Saccharum officinarum. Sukrosa merupakan sumber karbon terbaik untuk produksi eksopolisakarida di dalam medium cair ATCC 14 apabila dibandingkan dengan glukosa, laktosa, dan 4-hydroxyphenil acetic acid (4-HAA). Eksopolisakarida yang dihasilkan dari ketiga bakteri tersebut masing-masing 8,04 (P. fluorescens PG7II.1); 2,0 (Flavobacterium sp. PG7II.2) dan 1,82 mg/mL (P. diminuta PG7II.9). Inokulasi ketiga isolat tersebut ke dalam bahan tanah mineral memberikan indeks stabilitas agregat (ASI) sebesar 114 setelah 60 hari inkubasi pada suhu ruang. Nilai indeks ini berbeda secara nyata apabila dibandingkan dengan bahan tanah mineral tanpa inokulan. Jumlah suspensi bakteri yang diperlukan untuk meningkatkan nilai indeks stabilitas agregat di dalam bahan tanah mineral secara optimum ialah 12,5% (v/b), dengan jumlah populasi bakteri 109 CFU per mL.

Peningkatan kemantapan agregat tanah mineral oleh bakteri penghasil eksopolisakarida Aggregate stability improvement of mineral soil by exopolysaccharide-producing bacteria

Summary Pseudomonas fluorescens PG7II.1, Flavobacterium sp. PG7II.2, and Pseudomonas diminuta PG7II.9 have a potential to produce exopolysaccharide which help the formation and stabilization of soil aggregate. These bacteria have been isolated from the rhizosphere of Saccharum officinarum. Exopolysaccharide production in ATCC 14 liquid medium with sucrose was higher than that obtained from glucose, lactose, and 4-hydroxyphenil acetic acid (4-HAA) as a carbon sources. Producing of exopolysaccharide from these bacteria were 8.04 (P. fluorescens PG7II.1), 2.0 (Flavo-bacterium sp. PG7II.2) and 1.82 mg/mL (P. diminuta PG7II.9). Aggregate Stability Index (ASI) of mineral soil material was 114 when inoculated by these isolates after 60 days incubation period at ambient temperature. The ASI value of inoculated mineral soil material significantly different with uninoculated. The optimum of bacterial suspension to increase aggregate stability of mineral soil material was 12.5% (v/w) consisted of 109 CFU per mL. Ringkasan Pseudomonas fluorescens PG7II.1, Flavobacterium sp. PG7II.2, dan Pseudomonas diminuta PG7II.9, memiliki potensi dalam menghasilkan eksopolisakarida untuk pem-bentukan dan kemantapan agregat tanah. Ketiga bakteri tersebut diisolasi dari rhizosfer Saccharum officinarum. Sukrosa merupakan sumber karbon terbaik untuk produksi eksopolisakarida di dalam medium cair ATCC 14 apabila dibandingkan dengan glukosa, laktosa, dan 4-hydroxyphenil acetic acid (4-HAA). Eksopolisakarida yang dihasilkan dari ketiga bakteri tersebut masing-masing 8,04 (P. fluorescens PG7II.1); 2,0 (Flavobacterium sp. PG7II.2) dan 1,82 mg/mL (P. diminuta PG7II.9). Inokulasi ketiga isolat tersebut ke dalam bahan tanah mineral memberikan indeks stabilitas agregat (ASI) sebesar 114 setelah 60 hari inkubasi pada suhu ruang. Nilai indeks ini berbeda secara nyata apabila dibandingkan dengan bahan tanah mineral tanpa inokulan. Jumlah suspensi bakteri yang diperlukan untuk meningkatkan nilai indeks stabilitas agregat di dalam bahan tanah mineral secara optimum ialah 12,5% (v/b), dengan jumlah populasi bakteri 109 CFU per mL.

Co-inoculation of Mesorhizobium sp. and plant growth promoting rhizobacteria Pseudomonas sp. as bio-enhancer and bio-fertilizer in chickpea (Cicer arietinum L.)

The present investigation was undertaken to study the synergistic effect of recommended Mesorhizobium sp. (LGR -33) (Meso) and native potential PGPR Pseudomonas sp. (PGPR 2 and PGPR 3) along with reference strain Pseudomonas diminuta (LK884) on bio-enhancing activity, symbiotic parameters and grain yield in desi (PBG 1) and kabuli (BG 1053) under field conditions in chickpea during rabi 2009-2010. Significant improvement in growth and symbiotic parameters was observed with co-inoculation of Mesorhizobium sp. with native potential Pseudomonas sp. PGPR as compared to single inoculants of Mesorhizobium sp. in both varieties. Maximum improvement in symbiotic parameters was observed with co-inoculation of Mesorhizobium sp. and PGPR 3 followed by native PGPR 2 as compared to LK884 (reference). On an average, co-inoculation of Mesorhizobium sp. with PGPR 3 improved the yield by 7.0% (desi) and 5.3% (kabuli) over Mesorhizobium sp. alone. It appears that native potential Pseudomonas sp. PGPR can be explored as potent bio-enhancers and bio-fertilizers along with Mesorhizobium sp. in chickpea under low input technology programme of sustainable agriculture.

Population of Pratylenchus coffeae (Z.) and growth of Arabica coffee seedling inoculated by Pseudomonas diminuta L. and Bacillus subtilis (C.).

Pratylenchus coffeae is a parasitic nematoda that infected the roots of some plants, one of them is coffee. The Infection of Pratylenchus coffeae cause root tissue damage that led to root lession and make root become rotten, it will interfere the ability of roots to absorb water and nutrients in the soil which resulted in the growth of plants. At the moment, control of Pratylenchus coffeae are following integrated pests management (IPM) program, which integrated between the use of coffee resistant clone and application of biological agents. Research on biological control was conducted more intensive, at the moment; due to it is friendlier save against environment and cheaper then using chemical nematicides. The research was conducted to know the effects of Micorrhiza Helper Bacteria (MHB),Pseudomonas diminuta and Bacillus subtilis in suppressing the population of P. coffeaeas well as their effect on growth of coffee seedling. Coffee arabica (Coffea arabica L.) seedling one moth old were used in the experiment. The experiment prepared with eight treatments and five replications, as follows: A (Pseudomonas diminuta with density of 108 cfu / ml), B (Pseudomonas diminuta with density of 2x108 cfu / ml), C (Bacillus subtilis with density of 108 cfu / ml ), D (Bacillus subtilis with density 2x108 cfu / ml), E (Carbofuran nematicide 5 g formulation / pot), F (Pseudomonas diminuta and Bacillus subtilis with each density of 108 cfu / ml), K- (Nematoda inoculation but without bacteria and nematicide), K+ (coffee seedling without any additional treatment). The experiment was conducted for sixteen weeks or about four months. The results of the experiment showed that application of MHB could suppress population of P. coffeae and increase coffee seedling growth significantly. Inoculation of B. subtilis at 108 cfu per seedling suppressed significantly nematoda population of 71.3% compared with untreated seedling but inoculated with nematoda. It was not significant different with carbofuran treatment which could suppress nematoda population by 89.7%. The same result also occur on the treatment of P. diminuta at density level 2.108 cfu/seedling, which could suppress nematoda population by 64.2%. Seedling growth were treated with MHB also significantly increase compared with seedling without treatment and inoculation of nematodas, especially on the treatment of B.subtilis at density level 108 cfu and P.diminuta at density level of 108 cfu, with increasing level of 35.4% and 34.2 %, respectively.Keywords: MHB (Mycorrhiza Helper Bacteria), Arabica coffee (Coffea arabica L.), Pratylenchus coffeae, Bacillus subtilis, Pseudomonas diminuta.