Plant growth promotion and Penicillium citrinum

<p>Abstract</p> <p>Background</p> <p>Endophytic fungi are known plant symbionts. They produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. Coastal dunes are nutrient deficient and offer harsh, saline environment for the existing flora and fauna. Endophytic fungi may play an important role in plant survival by enhancing nutrient uptake and producing growth-promoting metabolites such as gibberellins and auxins. We screened roots of <it>Ixeris repenes </it>(L.) A. Gray, a common dune plant, for the isolation of gibberellin secreting endophytic fungi.</p> <p>Results</p> <p>We isolated 15 endophytic fungi from the roots of <it>Ixeris repenes </it>and screened them for growth promoting secondary metabolites. The fungal isolate IR-3-3 gave maximum plant growth when applied to waito-c rice and <it>Atriplex gemelinii </it>seedlings. Analysis of the culture filtrate of IR-3-3 showed the presence of physiologically active gibberellins, GA₁, GA₃, GA₄and GA₇(1.95 ng/ml, 3.83 ng/ml, 6.03 ng/ml and 2.35 ng/ml, respectively) along with other physiologically inactive GA₅, GA₉, GA₁₂, GA₁₅, GA₁₉, GA₂₀and, GA₂₄. The plant growth promotion and gibberellin producing capacity of IR-3-3 was much higher than the wild type <it>Gibberella fujikuroi</it>, which was taken as control during present study. GA₅, a precursor of bioactive GA₃was reported for the first time in fungi. The fungal isolate IR-3-3 was identified as a new strain of <it>Penicillium citrinum </it>(named as <it>P. citrinum </it>KACC43900) through phylogenetic analysis of 18S rDNA sequence.</p> <p>Conclusion</p> <p>Isolation of new strain of <it>Penicillium citrinum </it>from the sand dune flora is interesting as information on the presence of <it>Pencillium </it>species in coastal sand dunes is limited. The plant growth promoting ability of this fungal strain may help in conservation and revegetation of the rapidly eroding sand dune flora. <it>Penicillium citrinum </it>is already known for producing mycotoxin citrinin and cellulose digesting enzymes like cellulase and endoglucanase, as well as xylulase. Gibberellins producing ability of this fungus and the discovery about the presence of GA₅will open new aspects of research and investigations.</p

Structure-Based Rational Design of a Toll-like Receptor 4 (TLR4) Decoy Receptor with High Binding Affinity for a Target Protein

Repeat proteins are increasingly attracting much attention as alternative scaffolds to immunoglobulin antibodies due to their unique structural features. Nonetheless, engineering interaction interface and understanding molecular basis for affinity maturation of repeat proteins still remain a challenge. Here, we present a structure-based rational design of a repeat protein with high binding affinity for a target protein. As a model repeat protein, a Toll-like receptor4 (TLR4) decoy receptor composed of leucine-rich repeat (LRR) modules was used, and its interaction interface was rationally engineered to increase the binding affinity for myeloid differentiation protein 2 (MD2). Based on the complex crystal structure of the decoy receptor with MD2, we first designed single amino acid substitutions in the decoy receptor, and obtained three variants showing a binding affinity (KD) one-order of magnitude higher than the wild-type decoy receptor. The interacting modes and contributions of individual residues were elucidated by analyzing the crystal structures of the single variants. To further increase the binding affinity, single positive mutations were combined, and two double mutants were shown to have about 3000- and 565-fold higher binding affinities than the wild-type decoy receptor. Molecular dynamics simulations and energetic analysis indicate that an additive effect by two mutations occurring at nearby modules was the major contributor to the remarkable increase in the binding affinities

Characteristics of Type 2 Diabetes in Terms of Insulin Resistance in Korea

The aim of this study was to assess the implications of insulin resistance on the clinical and biochemical profiles of Korean type 2 diabetic patients. 122 patients with type 2 diabetes underwent a short insulin tolerance test to assess insulin resistance. Subjects were classified in tertiles according to ISI (insulin sensitivity index), and the tertile I (the insulin-resistant group) and tertile III (the insulin-sensitive group) clinical and biochemical parameters were compared. Age, waist circumference (WC), systolic blood pressure (SBP), HbA1c, body fat content, and fasting plasma glucose were significantly higher in tertile I than tertile III (all p < 0.05). The frequency of hypertension and family history of cerebrovascular disease (CVD) were greater in tertile I than III (p < 0.05). To evaluate the factors affecting ISI, multiple regression was performed, and age, WC, SBP, HbA1c, and body fat content were found to be independently related to insulin resistance (p < 0.05). Old age, hypertension, central obesity, and poor glycemic control were identified as clinical parameters of insulin resistance in Korean type 2 diabetic patients

REAL-TIME ADAPTIVE COLOR SNAKE TRACKER USING CONDENSATION ALGORITHM

Abstract: Motion tracking and object segmentation are the most fundamental and critical problems in vision tasks such as motion analysis. An active contour model, snake, was developed as a useful segmenting and tracking tool for rigid or non-rigid objects. Snake is designed on the basis of snake energies. Segmenting and tracking can be executed successfully by energy minimization. In this research, two new paradigms for segmentation and tracking are suggested. First, because the conventional method uses only intensity information, it is difficult to separate an object from its complex background. Therefore, a new energy and design schemes should be proposed for the better segmentation of objects. Second, conventional snake can be applied in situations where the change between images is small. If a fast moving object exists in successive images, conventional snake will not operate well because the moving object may have large differences in its position or shape, between successive images. Snake&apos;s nodes may also fall into the local minima in their motion to the new positions of the target object in the succeeding image. For robust tracking, the condensation algorithm was adopted to control the parameters of the proposed snake model called &quot;adaptive color snake model&quot;. The effectiveness of the ACSM is verified by appropriate simulations and experiments

An Auction-Based Dispatching Method for an Electronic Brokerage of Truckload Vehicles

ABSTRACT This study suggests an electronic brokerage system that has the capability of efficiently matching dispatching delivery tasks with trucks. In the brokerage system, individual truck drivers and shippers are allowed to participate in the dispatching process through the internet or wireless communication. An auction-based dispatching method for the electronic brokerage system is suggested. The basic rationale of the auction-based dispatching method-which is a distributed decision-making process-is discussed. The performance of the suggested algorithms is evaluated by a simulation study

Self-tuning Control for Articulated Robots Using the Plestan's Method

A self-tuning controller is proposed for an articulated robot using the Plestan’s method. To this end, we reconstruct the articulated robot dynamics exploiting the time-delay estimation (TDE) technique. The closed-loop error dynamics is described with sliding variables and TDE error; then, the Plestan’s sliding mode based gain-adaptation law is incorporated with the TDE technique. The stability of the overall dynamics is proven in the sense of Lyapunov. As a result, self-tuning of the gain is realized through the sliding variable. When the TDE error increases due to the nonlinear effect such as friction, the adaptive gain is automatically adjusted to counteract the TDE error. Chattering can be avoided because the sliding mode based gain dynamics does not allow the gain increase to an excessively high value. The superiority of the proposed self-tuning controller is demonstrated by comparative experiments on a multiple joints robot setup