Phosphonates and Their Degradation by Microorganisms

Phosphonates are a class of organophosphorus compounds characterized by a chemically stable carbon-to-phosphorus (C–P) bond. Wide occurrence of phosphonates among xenobiotics polluting the environment has aroused interest in pathways and mechanisms of their biodegradation. Only procaryotic microorganisms and the lower eucaryotes are capable of phosphonate biodegradation via several pathways. Destruction of the non activated C–P bond by the C–P lyase pathway is of fundamental importance, and understanding of the process is a basic problem of biochemistry and physiology of microorganisms. This review offers analysis of available data on phosphonate degrading microorganisms, degradation pathways, and genetic and physiological regulation of this process.     

Breeding birds from reedbeds to alpine meadows

The main processes that determine the behaviour ofheavy metals in the Scheldt estuary are tidalhydrodynamics, sediment transport, and sorption ofheavy metals on suspended matter. The water qualitymodel WASP is applied to simulate the spatialdistribution of five heavy metals in the estuary,under average hydrodynamic and suspended sedimenttransport regimes. First, the hydrodynamical part ofthe model is constructed and the results are verifiedby comparison with measured water levels and flowvelocities. Secondly, a salt transport model is set upin order to evaluate the hydrodynamical dispersivemixing characteristics. Thirdly, a suspended sedimenttransport model is constructed and finally a transportmodel for heavy metals. The simulated distributions of the sorbedamounts of heavy metals, suspended sediment andsalinity in the estuary agree well with observations.The calculated profiles of dissolved and sorbedconcentrations of heavy metals in the water columnindicate an accumulation of heavy metals in the zoneof the turbidity maximum, while closer to the sea theconcentrations diminish due to mixing of the pollutedfluvial sediments with unpolluted marine sediments andbecause of sediment deposition in the estuary. It canbe concluded that only a small part of the heavymetals reaches the sea. This revised version was published online in July 2006 with corrections to the Cover Date.     

3. NOTES ON OSPREY,EGYPTIAN COOSE AND SPECKLED PICEON

Rich, P. V. &; Walker, C. A. 1983. A new genus of Miocene flamingo from East Africa. Ostrich 54:95-104.

Study of fossil flamingo (Phoenicopteridae) remains from the Miocene of East Africa suggests that a new genus, Leakeyornis, should be recognized to include Phoenicopterus aethiopicus Harrison &; Walker 1976. Osteologically this new genus is a mosaic between the three genera of living flamingoes, clearly distinct from all fossil forms, and possibly most closely related to Phoeniconaias, the Lesser Flamingo of East Africa.     

Variation in foraging investment during the intermolt interval and before egg-laying in the spiderNephila clavipes (Araneae: Araneidae)

Repeated observations were made of marked, freeliving females in three disjunct populations of the orb-weaving spider Nephila clavipes,recording orb size and structure and barrier web complexity. These longitudinal studies revealed regular patterns of variation in orb size associated with the molting cycle and cycle of egg maturation. Juveniles maintained in an insectary under a controlled feeding regime exhibited similar variation in orb size. All spiders ceased orb renewal prior to molting and the majority replaced the viscid orb with a nonviscid platform prior to molting. Differences among the populations in molting web structure are discussed in light of differences in the physical and biological environments. Cessation of orb renewal corresponded temporally with reported physiological changes associated with the molt cycle and possibly reflect changes in resource partitioning between growth and foraging during the molt cycle.     

Thermal structure,heat content and stability of two lakes in The National Park of Rio Doce Valley (Minas Gerais,Brazil)

The thermal structure, heat content and stability were studied in Lakes Dom Helvécio and Carioca during an annual cycle. It was found that the maximum heat content, stability and work of the wind in Lake Dom Helvécio correspond to two, four and four times, respectively, the values for the Lake Carioca. These difference can be attributed to morphometric differences in the lakes. A long-term record of heat content and stability for lake Carioca is also presented. Diel variations were studied in summer and winter. The tropicality of the lakes is discussed and compared with other lacustrine systems.     

Endogenous Control of Photosynthetic Activity during Progressive Drought: Influence of Final Products of Photosynthesis

Photosynthetic activities and the redox states of photosystem I (PSI) and photosystem II (PSII) in intact leaves of cucumber plants (Cucumis sativus L.), as well as the sucrose and starch contents were examined under conditions of ongoing soil water deficit imposed by the cessation of watering. As the soil drought progressed, the maximum rate of photosynthetic CO₂ fixation was shown to decrease. These changes in the maximum photosynthetic rate occurred synchronously with changes in the maximum quantum yield of photosynthesis. Under soil water deficit, the reduced form of PSII primary acceptor Q _A was accumulated only at photon flux densities of about 100 mol/(m² s). At such photon flux densities, the changes in nonphotochemical quenching (qN) induced by soil water deficit were opposite to changes in photochemical quenching parameter (1 – qP). Irrespective of the duration of soil drought, the relationship between steady-state concentrations of photochemically inactive reaction centers of PSI and PSII (the fractions of P700 and Q _A in the oxidized and reduced state, respectively) was almost linear, which provides evidence for the concerted operation of both photosystems. The conditions of soil water deficit promoted sucrose accumulation in the source leaf, which was paralleled by a substantial decrease in the amount of starch in the same leaf. The highest content of sucrose in the leaf after a 7-day drought was correlated with the largest decrease in photosynthetic activity. It is concluded that the progressive drought triggers an endogenous mechanism that regulates photosynthesis through feedback relations, namely, the inhibition of photosynthesis by its end products.     

Influences of the reproductive cycle on condition of marine catfishes (Siluriformes,Ariidae) in a coastal area at southeastern Brazil

Marine catfishes use estuaries and bays as part of their life cycle for spawning and feeding purposes, respectively. We compared three species of the family Ariidae in two different environmental conditionsa relatively stable bay site and an estuarine site, which differ in their magnitudes of environmental fluctuation to investigate effects of spawning on condition. We found differences in the parameter b (slope) and in they-intercept (a) among species and sexes. The parameter a varied inversely with b, and thus is not a good indicator to express fish condition. Condition factor did not differ between the two sites for species and sexes when we consider the pooled data. Overall condition was associated with reproductive process, and was high before the reproductive season, decreasing during the spawning period in the estuary, then increasing when fish move to the bay (April–August). Temporal segregation in the reproductive period and small-scale movements between the estuary and the bay are the probable mechanisms to optimize the use of the area by the three species.     

The pull of the Central Flyway? Veeries breeding in western Canada migrate using an ancestral eastern route

Understanding non‐breeding season movements and identifying wintering areas of different populations of migratory birds is important for establishing patterns of migratory connectivity over the annual cycle. We analyzed archival solar geolocation (N = 5) and global positioning data (N = 1) to investigate migration routes, stopover sites, and wintering areas of a western‐most breeding population of Veeries (Catharus fuscescens) in the Pemberton Valley, British Columbia, Canada. Geolocation data were analyzed using a Bayesian state‐space model to improve likely position estimates. We compared our results with those from a Veery population located ~250 km east across a mountain chain in the Okanagan Valley, British Columbia, and with an eastern population in Delaware, U.S.A. Migrating Veeries from the Pemberton Valley used an eastern trajectory through the Rocky Mountains to the Great Plains to join a central flyway during fall and spring migration, a route similar to that used by Veeries breeding in the Okanagan Valley. However, wintering destinations of Pemberton Valley birds were more varied, with inter‐individual wintering distances ~1000 km greater than birds from the Okanagan Valley population and ~500 km from the previously known winter range of Veeries. The observed eastern migration path likely follows an ancestral route that evolved following the most recent glacial retreat. Consistent with patterns observed from the Okanagan and Delaware populations, Veeries from the Pemberton Valley undertook an intra‐tropical migration on the wintering grounds, but this winter movement differed from those of previously studied populations. Such winter movements may thus be idiosyncratic or show coarse population associations. Intra‐wintering‐ground movements likely occur either in response to seasonal changes in habitat suitability or as a means of optimizing pre‐migratory fueling prior to long‐distance spring movements to North America.     

Total enzymatic synthesis of cholecystokinin CCK-5

Summary. This paper describes the enzymatic synthesis of the C-terminal fragment H-Gly-Trp-Met-Asp-Phe-NH₂ of cholecystokinin. Immobilized enzymes were used for the formation of all peptide bonds except thermolysin. Beginning the synthesis with phenylacetyl (PhAc) glycine carboxamidomethyl ester (OCam) and H-Trp-OMe by using immobilized papain as biocatalyst in buffered ethyl acetate, the dipeptide methyl ester was then coupled directly with Met-OEt·HCl by -chymotrypsin/Celite 545 in a solvent free system. For the 3+2 coupling PhAc-Gly-Trp-Met-OEt had to be converted into its OCam ester.The other fragment H-Asp(OMe)-Phe-NH₂ resulted from the coupling of Cbo-Asp(OMe)-OH with H-Phe-NH₂·HCl and thermolysin as catalyst, followed by catalytic hydrogenation.Finally PhAc-Gly-Trp-Met-Asp-Phe-NH₂ was obtained in a smooth reaction from PhAc-Gly-Trp-Met-OCam and H-Asp(OMe)-Phe-NH₂ with -chymotrypsin/Celite 545 in acetonitrile, followed by basic hydrolysis of the -methyl ester. The PhAc-group is removed with penicillin G amidase and CCK-5 is obtained in an overall isolated yield of 19.6%.