Use of an Electrochemical Split Cell Technique to Evaluate the Influence of Shewanella oneidensis Activities on Corrosion of Carbon Steel

Microbially induced corrosion (MIC) is a complex problem that affects various industries. Several techniques have been developed to monitor corrosion and elucidate corrosion mechanisms, including microbiological processes that induce metal deterioration. We used zero resistance ammetry (ZRA) in a split chamber configuration to evaluate the effects of the facultatively anaerobic Fe(III) reducing bacterium Shewanella oneidensis MR-1 on the corrosion of UNS {"type":"entrez-nucleotide","attrs":{"text":"G10180","term_id":"942029"}}G10180 carbon steel. We show that activities of S. oneidensis inhibit corrosion of steel with which that organism has direct contact. However, when a carbon steel coupon in contact with S. oneidensis was electrically connected to a second coupon that was free of biofilm (in separate chambers of the split chamber assembly), ZRA-based measurements indicated that current moved from the S. oneidensis-containing chamber to the cell-free chamber. This electron transfer enhanced the O₂ reduction reaction on the coupon deployed in the cell free chamber, and consequently, enhanced oxidation and corrosion of that electrode. Our results illustrate a novel mechanism for MIC in cases where metal surfaces are heterogeneously covered by biofilms.     

A new centric fusion translocation in cattle: rob (13;19)

A new Robertsonian translocation has been found in cattle. A bull from Marchigiana breed (central Italy) was found to be a heterozygous carrier of a centric fusion translocation involving cattle chromosomes 13 and 19 according to RBA-banding and cattle standard nomenclatures. CBC-banding revealed the dicentric nature of this new translocation, underlining the recent origin of this fusion. In fact, both the bull's parents and relatives had normal karyotypes. In vitro fertilization tests were also performed in the bull carrying the new translocation, in two bulls with normal karyotypes (control) and in four other bulls carrying four different translocations.     

An efficient method for estimating vein density of Glossopteris and its application

Glossopteris-type leaves are the most abundant floristic element from the Gondwanan continent and are recorded throughout the Permian, which was a period of extreme icehouse-to-hothouse climatic global change. Fossil leaf traits can be useful for the reconstruction of palaeoenvironments and identification of climatic changes throughout geological time, but the conservative morphology of Glossopteris leaves has thus far made them difficult to use for this purpose. If the characters of Glossopteris can be better quantified then it should make them useful for tracking environmental changes over a wide geographical area and over a long time interval. Venation density is a highly variable leaf trait that might be useful for this purpose. This trait can be calculated, usually as vein length per centimetre squared, but this can be a time-consuming procedure. In this paper we propose a new rapid method to estimate venation density in a conical sector of Glossopteris leaf lamina using an accurate linear model whose predictors are three linear venation densities, measured as veins per centimetre. In addition to substantially reducing the data collection time, it is less biased and more reproducible than methods applied previously with this leaf type. Using this more robust method, preliminary results significantly distinguish the venation densities of leaves produced in wet and drier ecosystems, matching a pattern similar to modern plants. This is the first survey using a large sample size to reveal that environmental stress controlled the vein architecture of Palaeozoic plants, in a manner similar to plants in modern ecosystems.     

Approaches to localizing disease genes as applied to cystic fibrosis.

Using chromosome jumping and walking and restriction fragment length polymorphism (RFLP) analysis, we have defined the region which must contain the cystic fibrosis gene. DNA segments spanning approximately 250 kb in the direction of the gene were isolated and used to identify several new polymorphisms informative in cystic fibrosis families. These RFLPs include a highly polymorphic, CA/GT repeat, and a 10 bp insertion uncovered using the polymerase chain reaction. By analyzing a family with a recombination near the gene, we can exclude this region as containing the mutation. Data on the extent of linkage disequilibrium of these markers provides additional information on where the gene is located.     

Attractiveness of Different Food Resources to Dung Beetles (Coleoptera: Scarabaeidae) of a Dry Tropical Area

Excrement scarcity is one of the main historical factors leading dung beetles to adapt to other food resources. In the Caatinga, a seasonally tropical dry forest, harsh environmental conditions seem to restrict the availability of food resources. In this scenario, the aim of our study was to experimentally investigate the attractiveness of different potential food resources to these insects in the Caatinga. Field samplings were performed, and we tested five resources in pitfall baited traps: excrement, carrion, fruits of two species of columnar cacti, and seeds of one species of Euphorbiaceae (Jatropha mollissima (Pohl)). In a controlled setting, we tested dietary preferences of Deltochilum verruciferum Felsche by offering one or two resources simultaneously. In the field experiments, 297 dung beetles (9 species) were recovered from the traps, and D. verruciferum was the most abundant species. Carrion and excrement were the most attractive resources. Controlled dietary preference tests with D. verruciferum evidenced that these beetles used all tested food resources, excrement and carrion most pronouncedly. Our findings support copro-necrophagy as the main feeding habit of D. verruciferum, but also suggest that alternative resources might be utilized if preferred resources are scarce.     

Functional reorganization of dung beetle assemblages in forest-replacing sugarcane plantations

Journal of Insect Conservation - Tropical forests worldwide have succumbed to rapid conversion into agricultural landscapes, but the local- and landscape-scale drivers of functional diversity and...     

Heme binding inhibits the fibrillization of amyloidogenic apomyoglobin and determines lack of aggregate cytotoxicity

Myoglobin is an alpha-helical globular protein containing two highly conserved tryptophanyl residues at positions 7 and 14 in the N-terminal region. The double W/F replacement renders apomyoglobin highly susceptible to aggregation and amyloid-like fibril formation under physiological conditions. In this work we analyze the early stage of W7FW14F apomyoglobin aggregation following the time dependence of the process by far-UV CD, Fourier-transform infrared (FTIR) spectroscopy, and heme-binding properties. The results show that the aggregation of W7FW14F apomyoglobin starts from a native-like globin state able to bind the prosthetic group with spectroscopic properties similar to those observed for wild-type apoprotein. Nevertheless, it rapidly aggregates, forming amyloid fibrils. However, when the prosthetic group is added before the beginning of aggregation, amyloid fibrillization is inhibited, although the aggregation process is not prevented. Moreover, the apomyoglobin aggregates formed in these conditions are not cytotoxic differently from what is observed for all amyloidogenic proteins. These results open new insights into the relationship between the structure adopted by the protein into the aggregates and their ability to trigger the impairment of cell viability.     

A new case of reciprocal translocation in a young bull: rcp(11;21)(q28;q12)

Routine cytogenetic investigations of the Chianina cattle (BTA) breed revealed the presence of longer and smaller chromosomes than the largest (BTA1) and smallest (BTA29) chromosomes in the cells of a young, normal-looking bull used for reproduction. Application of both RBA-banding and Ag-NOR techniques, as well as the use of the FISH technique and specific molecular markers of both BTA11 (IL1B, ASS and LGB) and BTA21 (SERPINA and D21S45) established that these two abnormal chromosomes were the product of a reciprocal translocation between BTA11 and BTA21. Both der(11) and der(21) were C-band positive and the chromosome regions affected were rcp(11;21)(q28;q12). The young bull had a normal body conformation, including external genitalia, normal levels of testosterone (as in the control) and non-detectable levels of both 17 beta-estradiol and progesterone (as in the control). The animal never showed libido in the presence of both males and females in oestrus. After slaughter at 18 months, histological evaluation revealed normal organized testes, seminiferous tubules and epididymis but with poor proliferative germ cells consisting mainly of spermatogonia, middle pachytene spermatocytes and early spermatids with late spermatids and spermatozoa being very rare.     

Distributions for Key Exposure Factors Controlling the Uptake of Xenobiotic Chemicals by Great Blue Herons (Ardea herodius) through Ingestion of Fish

A variety of exposure factors ultimately control the uptake of xenobiotic chemicals by colonial piscivorous birds, such as herons and egrets. These factors, which include feeding rate for various food sources, feeding territory size, and body weight, are critical to the implementation of models commonly used to predict ecological risks. A critical evaluation of literature on avian behavior, physiology, and ecology was conducted in order to identify those variables that most strongly influence uptake of chemicals by herons and egrets. After developing a database of such exposure factors, we identified each factor's range, central tendency, and distribution. Sufficient information was available to allow the development of statistical distributions for body weight, fraction of diet from fish, prey length, distance to foraging site, and feeding territory size for great blue herons. The five distributions presented in this paper are intended to support probabilistic assessments of potential risks to great blue herons. Distributions of exposure factors for great blue herons have not been previously published. Without such data, application of all but the most simple mechanistic models will require point estimates, most of which will be overly conservative and will not support accurate characterization of actual exposures of herons at hazardous waste sites.     

Durum wheat seedling responses to simultaneous high light and salinity involve a fine reconfiguration of amino acids and carbohydrate metabolism

Durum wheat plants are extremely sensitive to drought and salinity during seedling and early development stages. Their responses to stresses have been extensively studied to provide new metabolic targets and improving the tolerance to adverse environments. Most of these studies have been performed in growth chambers under low light [300–350 µmol m^?2 s^?1 photosynthetically active radiation (PAR), LL]. However, in nature plants have to face frequent fluctuations of light intensities that often exceed their photosynthetic capacity (900–2000 µmol m^?2 s^?1). In this study we investigated the physiological and metabolic changes potentially involved in osmotic adjustment and antioxidant defense in durum wheat seedlings under high light (HL) and salinity. The combined application of the two stresses decreased the water potential and stomatal conductance without reducing the photosynthetic efficiency of the plants. Glycine betaine (GB) synthesis was inhibited, proline and glutamate content decreased, while γ‐aminobutyric acid (GABA), amides and minor amino acids increased. The expression level and enzymatic activities of Δ1‐pyrroline‐5‐carboxylate synthetase, asparagine synthetase and glutamate decarboxylase, as well as other enzymatic activities of nitrogen and carbon metabolism, were analyzed. Antioxidant enzymes and metabolites were also considered. The results showed that the complex interplay seen in durum wheat plants under salinity at LL was simplified: GB and antioxidants did not play a main role. On the contrary, the fine tuning of few specific primary metabolites (GABA, amides, minor amino acids and hexoses) remodeled metabolism and defense processes, playing a key role in the response to simultaneous stresses.