Structure-Activity Relationship of Cytotoxic Natural Products from Indonesian Marine Sponges.

Indonesian marine natural products have been one of the most promising sources in the race to obtain potential drugs for cancer treatment. One of the primary producers of cytotoxic compounds is sponges. However, there are still limited sources of comprehensive reviews related to the relationship between the structure of isolated compounds and their cytotoxic activity. This review remarks the attempt to provide a preliminary guidance from the perspective of structure-activity relationship and its participation on marine natural products research. This guidance is segregated by the compound's classes and their cytotoxic targets to obtain and organized a reliable summary of inter-study of the isolated compounds and their cytotoxicity. Structure-activity relationship is well-known for its ability to tune the bioactivity of a specific compound, especially on synthetic organic chemistry and in silico study but rarely used on natural product chemistry. The present review is intended to narrow down the endless possibilities of cytotoxicity by giving a predictable structure-activity relationship for active compounds. In addition, bioactive framework leads were selected by uncovering a noticeable structure-activity relationship with the intervention of cytotoxic agents from natural sources, especially Indonesian marine sponge.

The efficiency of a new automated mosquito larval counter and its impact on larval survival.

To achieve consistent and standardized rearing for mosquito immature stages, it is crucial to control the initial number of larvae present in each larval tray. In addition, maintaining an optimal and synchronized development rate of larvae is essential to maximize the pupal production and optimize male sorting in a mass-rearing setting. Manual counting is labor intensive, time consuming and error prone. Therefore, this study aimed to investigate the use of a customized automated counter for the quantification of mosquito larvae. The present prototype of the mosquito larval counter uses a single counting channel consisting of three parts: a larvae dispenser, an electronic counting unit and computer control software. After the separation of the larvae from eggs and debris, batches of different numbers of Aedes aegypti first instar larvae were manually counted and introduced into the counter through the upper loading funnel and channeled out from the bottom of the counter by gravitational flow. The accuracy and repeatability of the mosquito larval counter were determined in relation to larval density and water quality. We also investigated its impact on larval survival. Results showed an impact of larval density and water quality on the accuracy of the device. A -6% error and a repeatability of +/- 2.56% average value were achieved with larval densities up to 10 larvae/mL of clean water. Moreover, the use of the mosquito larval counter did not have any effect on larval survival or development. Under recommended conditions, the mosquito larval counter can be used to enumerate the number of mosquito larvae at a given density. However, future developments involving the use of multiple channels or larger input larvae container would help to expand its use in large-scale facilities.

Control of Coptotermes havilandi (Isoptera: Rhinotermitidae) with hexaflumuron baits and a sensor incorporated into a monitoring and baiting program.

A sensor consisting of a wooden monitor painted with a conductive circuit of silver particle emulsion was placed in a monitoring station to detect feeding activity of the subterranean termite Coptotermes havilandi Holmgren. Sensor accuracy was 100% 1 mo after installation, but 9 mo after sensor placement, the rate declined to 73%. After the detection of C. havilandi in the stations, baits containing the chitin synthesis inhibitor hexaflumuron were applied in five colonies, and four colonies were eliminated within 3-5 mo. Baiting could not be completed for the remaining one colony because the site became inaccessible.

The Use of Generalization Gradients for the Study of Mediational Processes.

In Experiment I three groups (N = 60 college students) were presented with a 60° training stimulus (TS) and subsequently tested for generalization along a line-tilt dimension with the use of an asymmetrical test series. During training, one group labeled the TS with a high-imagery word, another with a low-imagery word, while a third served as a no-label control. While the control group showed an expected central tendency shift, the shift was completely inhibited for the high-imagery group. The low-imagery group's gradient appeared to show a partial inhibition effect, although statistical confirmation for a differential imagery effect was not obtained. In Experiment II (N = 180 college students) three words of high and three of low imagery were employed as labels. While the control condition resulted in a central tendency shift, both labeling conditions produced complete inhibition, indicating that verbal pretraining produces inhibitory effects regardless of the labels employed. The findings were discussed in terms of the acquired-distinctiveness-of-cues hypothesis.