Standardization of Inducer-Activated Broad Host Range Expression Modules: Debugging and Refactoring an Alkane-Responsive AlkS/PalkB Device

Although inducible heterologous expression systems have been available since the birth of recombinant DNA technology, the diversity of genetic devices and their coming together in the corresponding vectors often result in a lack of reproducibility and interoperability. In an effort to increase predictability of expression of genes of interest in a variety of possible bacterial hosts we propose a composition standard for debugging and reassembling all regulatory parts that participate in the performance of such devices. As a case study we addressed the n-octane and dicyclopropyl ketone (DCPK)-inducible PalkB promoter of the alkane biodegradation pOCT plasmid of Pseudomonas putida. The standardized expression module included an edited alkS transcription factor divergently expressed and separated from PalkB by a synthetic buffer sgement. The DNA sequence of the alkS gene was modified to alleviate the catabolite repression exerted by several carbon and nitrogen sources through the Crc/Hfq complex of some hosts. The PalkB promoter and the alkS variants were then formatted as SEVA (Standard European Vector Architecture) cargoes and their activity in P. putida quantified with GFP and luminiscent reporters. Despite considerable editing of the DNA sequences involved, the thereby refactored module basically kept the functioning parameters of the original configuration. The same qualities were inspected when the system was passed to Escherichia coli and P. aeruginosa. We argue that application of the compositional standard thereby implemented in the AlkS/PalkB module to other promoter/regulator pairs will enable more complex genetic programming in non-model bacteria.

The Clinical Impact of Accurate Cystine Calculi Characterization Using Dual-Energy Computed Tomography

Dual-energy computed tomography (DECT) has recently been suggested as the imaging modality of choice for kidney stones due to its ability to provide information on stone composition. Standard postprocessing of the dual-energy images accurately identifies uric acid stones, but not other types. Cystine stones can be identified from DECT images when analyzed with advanced postprocessing. This case report describes clinical implications of accurate diagnosis of cystine stones using DECT.

Avifaunal Diversity in Bulosao Watershed Forest Reserve Lawaan, Eastern Samar, Philippines

Bulosao Watershed Forest Reserve is regarded as one of the most important areas in terms of biodiversity in the island of Samar and within the greater Mindanao faunal region. Four study sites representing different habitat types, elevation range and degree of human disturbance were surveyed for their faunal composition. Standard faunal survey methods such as transect survey was used during the entire duration of the study. The methods were augmented with observations and ethnobiological interviews. A total of 41 species of birds belonging to 12 orders, 25 families and 35 genera were recorded. Of these, twelve (29%) are endemic to the Philippines and one to the greater Mindanao faunal region. Among avian species, sixteen (40%) are considered threatened or at risk. Major threats birds and other wildlife populations in the reserve include hunting and habitat alteration. Hunting among the local community is not only for subsistence but also for commercial purposes. Major activities leading to habitat destruction include conversion of logged-over areas into cultivation, illegal logging and indiscriminate collection of other forest products.

Iron particles isolated from the dura of pygmy sperm whales Kogia breviceps

Magnetite, a highly magnetic iron oxide, is a biomineralization product found in organisms sensitive to the earth's magnetic field. Biogenically produced magnetite differs from magnetite-bearing rocks of geological origin in crystalline morphology, size, and elemental composition. Standard paleomagnetic methods indicate that cetacean brain dura may also contain magnetite. Correllations have been documented between the distribution of cetacean live stranding events and anomalously minimal magnetic field intensities. This would suggest magnetoreceptive abilities in whales. Pygmy sperm whales are one of the most common cetaceans to strand alive in Florida. Therefore, it is of interest to determine whether pygmy sperm whale brain contains magnetite, as this will establish sensitivity to variations in the earth's magnetic field. Reported here are the results of isolation experiments to ascertain whether iron-rich particles are present in pygmy sperm whales, Kogia breviceps.