The ACIST power injection system reduces the amount of contrast media delivered to the patient, as well as fluoroscopy time, during diagnostic and interventional cardiac procedures

The ACIST injection system is an automatic power injection device that allows for online control of injection rate and volume of contrast. Limited data is available whether this technology allows reducing use of contrast and fluoroscopy time. Accordingly, we compared the use of this system to manual injection among 450 consecutive patients who underwent diagnostic coronary angiography and/or angioplasty who were randomly assigned to either manual contrast injection (control; n=198) or to the ACIST system (study group; n=252). The amount of contrast, fluoroscopy and total procedural times were recorded for each patient. In the diagnostic group, the mean total amount of contrast (including wasted) was reduced by 63% when the ACIST was used compared to control (100+/-42 ml versus 163+/-56 ml; P<0.001, respectively). When only the net amount of contrast delivered to the patient was considered, the differences were smaller (20%, P=0.004). During angioplasty, the amount of contrast was also lower in the ACIST group (206+/-65 versus 230+/-69, P=0.008), whereas no difference were noted in net amount of contrast. Fluoroscopy time was significantly shorter in the ACIST group compared to control both during diagnostic catheterization (4.7+/-3.5 min versus 6.3+/-5.5 min, respectively; P=0.014), and angioplasty (16.7+/-9.1 min versus 19.6+/-12.4 min, respectively; P=0.05). Routine utilization of the ACIST system during diagnostic and interventional procedure significantly reduced the total amount of contrast media used and fluoroscopy time.     

Exposing pepper plants to high day temperatures prevents the adverse low night temperature symptoms

Exposing pepper ( Capsicum annuum ) plants to extremely high day temperatures (HDT) (day/night temperatures of 36 ± 2/10 ± 2°C), obtained by keeping the greenhouse closed during the day to exploit solar heating, prevented the development of low night temperature (LNT) symptoms. Plants of cultivars Fiesta and Selica grown under LNTs (10 ± 2°C) and moderate day temperatures (25 ± 2°C) during winter exhibited retarded growth, reduced leaf numbers, and deformed fruits with few or no seeds. LNT caused a reduction in the number and quality of pollen grains: the reduction in pollen quality was associated with reduced starch accumulation in pollen grains at 3 days before anthesis (DBA) and a decrease of more than two-fold in total soluble sugars in the mature pollen grains. This inhibitory effect was associated with more than 50% reduction in the enzymatic activities of the cell wall-bound and soluble acid invertases that catalyze the hydrolysis of incoming sucrose molecules. All these symptoms were prevented by HDT treatment which matched the vegetative and reproductive performance of the plants to those of plants grown under optimal night temperature (ONT) conditions (day/night temperatures of 23 ± 2/18 ± 2°C). HDT also prevented the inhibitory effect of LNT on enzymatic activities of both invertases in pollen at 5 DBA and brought about the accumulation of high levels of starch in pollen at 3 DBA. The results presented could support the development of a novel procedure for producing greenhouse crops with minimum or even with no fuel consumption for heating during the winter nights in regions with bright and sunny days.     

Identification and Localization of a Rickettsia sp. in Bemisia tabaci (Homoptera: Aleyrodidae)

Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor “Candidatus Portiera aleyrodidarum,” an obligatory symbiotic bacterium which is housed in a special organ called the bacteriome. These insects are also home for a diverse facultative microbial community which may include Hamiltonella, Arsenophonus, Fritchea, Wolbachia, and Cardinium spp. In this study, the bacteria associated with a B biotype of the sweet potato whitefly Bemisia tabaci were characterized using molecular fingerprinting techniques, and a Rickettsia sp. was detected for the first time in this insect family. Rickettsia sp. distribution, transmission and localization were studied using PCR and fluorescence in situ hybridizations (FISH). Rickettsia was found in all 20 Israeli B. tabaci populations screened but not in all individuals within each population. A FISH analysis of B. tabaci eggs, nymphs, and adults revealed a unique concentration of Rickettsia around the gut and follicle cells, as well as a random distribution in the hemolymph. We postulate that the Rickettsia enters the oocyte together with the bacteriocytes, leaves these symbiont-housing cells when the egg is laid, multiplies and spreads throughout the egg during embryogenesis and, subsequently, disperses throughout the body of the hatching nymph, excluding the bacteriomes. Although the role Rickettsia plays in the biology of the whitefly is currently unknown, the vertical transmission on the one hand and the partial within-population infection on the other suggest a phenotype that is advantageous under certain conditions but may be deleterious enough to prevent fixation under others.     

Energy metabolism and evaporative water loss in the European free-tailed bat and Hemprich's long-eared bat (Microchiroptera): species sympatric in the Negev Desert

We compared the thermoregulatory abilities of two insectivorous bat species, Tadarida teniotis (mean body mass 32 g) and Otonycteris hemprichii (mean body mass 25 g), that are of different phylogenetic origins and zoogeographic distributions but are sympatric in the Negev Desert. At night, both were normothermic. By day, both were torpid when exposed to ambient temperatures (T(a)) below 25 degrees Celsius, with concomitant adjustments in metabolic rate (MR). Otonycteris hemprichii entered torpor at higher T(a) than T. teniotis, and, when torpid, their body temperatures (T(b)) were 1 degrees -2 degrees Celsius and 5 degrees -8 degrees Celsius above T(a), respectively; MR was correspondingly reduced. At night, the lower critical temperature of T. teniotis was 31.5 degrees Celsius, and that of O. hemprichii was 33 degrees Celsius. Mean nocturnal thermoneutral MR of T. teniotis was 37% greater than that of O. hemprichii. At high T(a), evaporative water loss (EWL) increased markedly in both species, but it was significantly higher in T. teniotis above 38 degrees Celsius. In both species, the dry heat transfer coefficient (thermal conductance) followed the expected pattern for small mammals, by day and by night. Total EWL was notably low in normothermic and torpid animals of both species, much lower than values reported for other bats, indicating efficient water conservation mechanisms in the study species. Comparing thermoregulatory abilities suggests that O. hemprichii is better adapted to hot, arid environments than T. teniotis, which may explain its wider desert distribution. By both standard and phylogenetically informed ANCOVA, we found no differences in basal metabolic rate (BMR) between desert and nondesert species of insectivorous bats, substantiating previous studies suggesting that low BMR is a characteristic common to insectivorous bats in general.     

Presence of a vanadium-dependent haloperoxidase in Botrytis cinerea

The presence of a haloperoxidase in the mycelium of Botrytis cinerea, extractable with buffer, is demonstrated. A low level of extracellular enzyme activity was also detected. The haloperoxidase from the fungus is a vanadium-dependent glycoprotein, with a pH optimum of about 5.5. Native gel electrophoresis indicates that it is a high molecular mass protein. It appears to react with antibodies against haloperoxidase from Caldariomyces fumago. Enzyme activity is increased 3.5-fold and 15-fold by culture of the fungus in the presence of NaCl or vanadium, respectively. Activity is partly reduced by removal of vanadium and activity can be restored by the addition of vanadium to the enzyme. The possible function of this haloperoxidase is discussed.     

Water status and associated processes mark critical stages in pollen development and functioning

Background

The male gametophyte developmental programme can be divided into five phases which differ in relation to the environment and pollen hydration state: (1) pollen develops inside the anther immersed in locular fluid, which conveys substances from the mother plant – the microsporogenesis phase; (2) locular fluid disappears by reabsorption and/or evaporation before the anther opens and the maturing pollen grains undergo dehydration – the dehydration phase; (3) the anther opens and pollen may be dispersed immediately, or be held by, for example, pollenkitt (as occurs in almost all entomophilous species) for later dispersion – the presentation phase; (4) pollen is dispersed by different agents, remaining exposed to the environment for different periods – the dispersal phase; and (5) pollen lands on a stigma and, in the case of a compatible stigma and suitable conditions, undergoes rehydration and starts germination – the pollen–stigma interaction phase.

Scope

This review highlights the issue of pollen water status and indicates the various mechanisms used by pollen grains during their five developmental phases to adjust to changes in water content and maintain internal stability.

Conclusions

Pollen water status is co-ordinated through structural, physiological and molecular mechanisms. The structural components participating in regulation of the pollen water level, during both dehydration and rehydration, include the exine (the outer wall of the pollen grain) and the vacuole. Recent data suggest the involvement of water channels in pollen water transport and the existence of several molecular mechanisms for pollen osmoregulation and to protect cellular components (proteins and membranes) under water stress. It is suggested that pollen grains will use these mechanisms, which have a developmental role, to cope with environmental stress conditions.     

Decoding the regulation of mast cell exocytosis by networks of rab GTPases

Exocytosis is a key event in mast cell functions. By this process, mast cells release inflammatory mediators, contained in secretory granules (SGs), which play important roles in immunity and wound healing but also provoke allergic and inflammatory responses. The mechanisms underlying mast cell exocytosis remained poorly understood. An essential step toward deciphering the mechanisms behind exocytosis is the identification of the cellular components that regulate this process. Because Rab GTPases regulate specific trafficking pathways, we screened 44 Rabs for their functional impacts on exocytosis triggered by the FcεRI or combination of Ca(2+) ionophore and phorbol ester. Because exocytosis involves the continuous reorganization of the actin cytoskeleton, we also repeated our screen in the presence of cytochalasin D that inhibits actin polymerization. In this paper, we report on the identification of 30 Rabs as regulators of mast cell exocytosis, the involvement of 26 of which has heretofore not been recognized. Unexpectedly, these Rabs regulated exocytosis in a stimulus-dependent fashion, unless the actin skeleton was disrupted. Functional clustering of the identified Rabs suggested their classification as Rabs involved in SGs biogenesis or Rabs that control late steps of exocytosis. The latter could be further divided into Rabs that localize to the SGs and Rabs that regulate transport from the endocytic recycling compartment. Taken together, these findings unveil the Rab networks that control mast cell exocytosis and provide novel insights into their mechanisms of action.     

ACCLIMATION TO LOW TEMPERATURE OF TWO ARTHROSPIRA PLATENSIS (CYANOBACTERIA) STRAINS INVOLVES DOWN‐REGULATION OF PSII AND IMPROVED RESISTANCE TO PHOTOINHIBITION1

This study aimed to compare the ability of two Arthrospira platensis (Nordst.) Gomont strains, M2 and Kenya, isolated from two different habitats, to acclimate to low temperature (15°C). Both strains had similar growth rates at 30°C, but once acclimated to low temperature, M2 showed a greater decline in growth (59% vs. 41% in the Kenya strain). We suggest that the Kenya strain acclimated better to low temperature by down‐regulating its photosynthetic activity through (i) decreasing antenna size and thus reducing energy flux into the photosystems; (ii) decreasing reaction center density (RC/CS_X) and the performance index, thus decreasing the trapping probability and electron transport rate while maintaining electron transport probability for electron transport beyond Q_A^? unchanged; (iii) increasing the energy dissipation flux. In contrast, the M2 strain showed no difference in antenna size and exhibited a much lower decrease in RC/CS_X and a lower dissipation rate. Hence, the Kenya strain minimized potential damage on the acceptor side of PSII compared to the M2 cells. Furthermore, acclimation to low temperature was accompanied by an improved mechanism for handling excess energy resulting in an enhanced ability of the Kenya strain to rapidly repair damaged PSII RCs and withstand a high photon flux density (HPFD) stress; this finding might be defined as a cross‐adaptation phenomenon. This study may provide a tool to identify strains suitable for outdoor mass‐production in different regions characterized by different climate conditions.