Coarser taxonomic resolutions are informative in revealing fish community abundance trends for the world’s warmest coral reefs

Coral Reefs - The Arabian Gulf is a natural laboratory to examine how subtropical coral reef ecosystems might change in responding to recurring heating events because of uniquely high water...     

Using Insect Electroantennogram Sensors on Autonomous Robots for Olfactory Searches

Robots designed to track chemical leaks in hazardous industrial facilities¹ or explosive traces in landmine fields² face the same problem as insects foraging for food or searching for mates³: the olfactory search is constrained by the physics of turbulent transport⁴. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity^5-6, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones⁷ but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells⁸ or toxic and illicit substances^9-11. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors¹². The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies¹³. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration¹⁴ or using nanostructured gas sensors that mimic insect antennae¹⁵.     

Association of VEGF genetic polymorphisms with prostate carcinoma risk and clinical outcome

OBJECTIVES: Vascular endothelial growth factor (VEGF) is a potent stimulus of angiogenesis that has an important role in many human malignancies including prostate carcinoma (PCa). We evaluated the role of the functional VEGF polymorphisms as genetic markers for PCa susceptibility and prognosis. METHODS: The study included 101 patients with PCa and [corrected] 100 age-matched healthy men. The VEGF genotypes -1154G>A were identified by allele-specific polymerase chain reaction (AS-PCR) and the genotypes -634G>C and 936C>T were identified by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). RESULTS: A negative association was found between VEGF -1154AA genotype and PCa risk (OR=0.27; P=0.009). Furthermore, the presence of the VEGF -1154A allele appeared to be associated with a decreased [corrected] risk of higher tumor grade (OR=0.37; P=0.01). A significant increased risk of prostate cancer was associated with the VEGF -634 (GC+CC) combined genotype (OR=1.95; P=0.02). The VEGF -634C allele was associated with the aggressive phenotype of prostate cancer as defined by the high histological grade (OR=3.48; P=0.007). The VEGF -1154A/-634G haplotype was negatively associated with PCa risk (OR=0.48; P=0.005) and high tumor grade compared to low grade (OR=0.37; P=0.02). CONCLUSIONS: Genetic variations in the VEGF may predict not only PCa risk but also tumor aggressiveness.     

Characterization and molecular cloning of thermostable alpha-amylase from Streptomyces sp.To1

Summary A new thermophilic Streptomyces sp. TO1, isolated from Tunisian soil, produced a thermostable alpha-amylase and pullulanase. The gene encoding for the alpha-amylase activity was cloned into the multicopy cloning plasmid pLM1 using S. lividans ZX1 as host strain. The ZX1 / pLM1 strain has the same activity than the initial TO1 strain and about 25 fold higher activity than the ZX1 strain. This alpha-amylase has an optimum of pH and temperature at 6 and 70 °C respectively.     

Vascular endothelial growth factor-induced secretion of fibronectin is ERK dependent

In severe asthma, cytokines and growth factors contribute to the proliferation of smooth muscle cells and blood vessels, and to the increased extracellular matrix deposition that constitutes the process of airway remodeling. Vascular endothelial growth factor (VEGF), which regulates vascular permeability and angiogenesis, also modulates the function of nonendothelial cell types. In this study, we demonstrate that VEGF induces fibronectin secretion by human airway smooth muscle (ASM) cells. In addition, stimulation of ASM with VEGF activates ERK, but not p38MAPK, and fibronectin secretion is ERK dependent. Both ERK activation and fibronectin secretion appear to be mediated through the VEGF receptor flt-1, as evidenced by the effects of the flt-1-specific ligand placenta growth factor. Finally, we demonstrate that ASM cells constitutively secrete VEGF, which is increased in response to PDGF, transforming growth factor-beta, IL-1beta, and PGE(2). We conclude that ASM-derived VEGF, through modulation of the extracellular matrix, may play an important role in airway remodeling seen in asthma.     

Effects of Sensory Behavioral Tasks on Pain Threshold and Cortical Excitability

Background/Objective

Transcutaneous electrical stimulation has been proven to modulate nervous system activity, leading to changes in pain perception, via the peripheral sensory system, in a bottom up approach. We tested whether different sensory behavioral tasks induce significant effects in pain processing and whether these changes correlate with cortical plasticity.

Methodology/Principal Findings

This randomized parallel designed experiment included forty healthy right-handed males. Three different somatosensory tasks, including learning tasks with and without visual feedback and simple somatosensory input, were tested on pressure pain threshold and motor cortex excitability using transcranial magnetic stimulation (TMS). Sensory tasks induced hand-specific pain modulation effects. They increased pain thresholds of the left hand (which was the target to the sensory tasks) and decreased them in the right hand. TMS showed that somatosensory input decreased cortical excitability, as indexed by reduced MEP amplitudes and increased SICI. Although somatosensory tasks similarly altered pain thresholds and cortical excitability, there was no significant correlation between these variables and only the visual feedback task showed significant somatosensory learning.

Conclusions/Significance

Lack of correlation between cortical excitability and pain thresholds and lack of differential effects across tasks, but significant changes in pain thresholds suggest that analgesic effects of somatosensory tasks are not primarily associated with motor cortical neural mechanisms, thus, suggesting that subcortical neural circuits and/or spinal cord are involved with the observed effects. Identifying the neural mechanisms of somatosensory stimulation on pain may open novel possibilities for combining different targeted therapies for pain control.     

Prompt chlorophyll fluorescence as a tool for crop phenotyping: an example of barley landraces exposed to various abiotic stress factors

The study examined photosynthetic efficiency of two barley landraces (cvs. Arabi Abiad and Arabi Aswad) through a prompt fluorescence technique under influence of 14 different abiotic stress factors. The difference in the behavior of photosynthetic parameters under the same stress factor in–between cv. Arabi Abiad and cv. Arabi Aswad indicated different mechanisms of tolerance and strategies for the conversion of light energy into chemical energy for both the landraces. This study confirmed the suitability of some chlorophyll fluorescence parameters as reliable biomarkers for screening the plants at the level of photosynthetic apparatus.     

Feeling by sight or seeing by touch?

We have addressed the role of occipital and somatosensory cortex in a tactile discrimination task. Sight-ed and congenitally blind subjects rated the roughness and distance spacing for a series of raised dot patterns. When judging roughness, intermediate dot spacings were perceived as being the most rough, while distance judgments generated a linear relation. Low-frequency rTMS applied to somatosensory cortex disrupted roughness without affecting distance judgments, while rTMS to occipital cortex disrupted distance but not roughness judgments. We also tested an early blind patient with bilateral occipital cortex damage. Her performance on the roughness determination task was normal; however, she was greatly impaired with distance judgments. The findings suggest a double-dissociation effect in which roughness and distance are primarily processed in somatosensory and occipital cortex, respectively. The differential effect of rTMS on task performance and corroborative clinical evidence suggest that occipital cortex is engaged in tactile tasks requiring fine spatial discrimination.     

Impacts of very warm temperature on egg production rates of three Acartiidae (Crustacea,Copepoda) in a Northern African lagoon

The daily Egg Production Rate (EPR) of the three Acartiidae copepods namely Acartia clausi, Paracartia latisetosa and Paracartia grani in the North Lagoon of Tunis was compared to temperature and food availability every season from March, 2003 to February, 2004 corresponding to the major seasonal peaks of their abundance and over a 20-days period. The daily EPR was evaluated by assuming a direct correlation with chlorophyll a, particulate organic carbon (POC), and some easily extractable macromolecular compounds from the seston, such as proteins, carbohydrates and lipids. The results showed significant differences in EPR between seasons and species. Temperature and salinity negatively affected the fecundity of A. clausi and positively that of P. latisetosa and P. grani. The A. clausi EPR was supported by chlorophyll a and sestonic proteins while that of P. latisetosa and P. grani correlated with POC suggesting that these two taxa feed on microzooplankton and detritus more than on phytoplankton. Overall, EPR data showed potential population recruitment evidently the highest in P. latisetosa in summer, P. grani in autumn and A. clausi in winter. Our results indicate that temperature and food quality are the determining factors of both abundance and reproduction of the copepods under study.