Mangrove growth rings: fact or fiction?

The analysis of tree rings in the tropics is less straightforward than in temperate areas with a demarcated unfavourable winter season. But especially in mangroves, the highly dynamic intertidal environment and the overriding ecological drivers therein have been a reason for questioning the existence of growth rings. This study aimed at casting light on growth rings in mangroves. In six mangrove species growing in Gazi Bay, Kenya (Sonneratia alba, Heritiera littoralis, Ceriops tagal, Bruguiera gymnorrhiza, Xylocarpus granatum and Lumnitzera racemosa), the occurrence of growth rings was examined. Growth rate of each species was determined based on a 1-year period using the cambial marking technique. The effect of climate was furthermore considered by comparing the results with a number of wood samples originating from contrasting climatic regions. We can conclude that for growth rings to appear in mangroves more than one condition has to be fulfilled, making general statements impossible and explaining the prevalent uncertainty. Climatic conditions that result in a range of soil water salinity experienced over the year are a prerequisite for the formation of growth rings. For species with an anatomy characterized by indistinct ring boundaries, this should be combined with a growth rate of at least 0.3 mm/year. The use of growth rings for age or growth rate determinations should thus be evaluated on a case by case basis

Characterization of novel components of the baculovirus per os infectivity factor complex

Baculovirus occlusion-derived virus (ODV) infects insect midgut cells under alkaline conditions, a process mediated by highly conserved per os infectivity factors (PIFs), P74 (PIF0), PIF1, PIF2, PIF3, PIF4, and PIF5 (ODV-E56). Previously, a multimolecular complex composed of PIF1, PIF2, PIF3, and P74 was identified which was proposed to play an essential role during ODV entry. Recently, more proteins have been identified that play important roles in ODV oral infectivity, including PIF4, PIF5, and SF58, which might work in concert with previously known PIFs to facilitate ODV infection. In order to understand the ODV entry mechanism, the identification of all components of the PIF complex is crucial. Hence, the aim of this study was to identify additional components of the PIF complex. Coimmunoprecipitation (CoIP) combined with proteomic analysis was used to identify the components of the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) PIF complex. PIF4 and P95 (AC83) were identified as components of the PIF complex while PIF5 was not, and this was confirmed with blue native PAGE and a second CoIP. Deletion of the pif4 gene impaired complex formation, but deletion of pif5 did not. Differentially denaturing SDS-PAGE further revealed that PIF4 forms a stable complex with PIF1, PIF2, and PIF3. P95 and P74 are more loosely associated with this complex. Three other proteins, AC5, AC68, and AC108 (homologue of SF58), were also found by the proteomic analysis to be associated with the PIF complex. Finally the functional significance of the PIF protein interactions is discussed

Proteomics of Tsetse salivary glands before and after infection with Trypanosoma parasite

Trypanosoma brucei causes African trypanosomosis to humans and cattle, against which there are no effective vaccines or drugs. The tsetse fly Glossina morsitans morsitans is the primary vector of the species of T. brucei group. At the moment there is limited knowledge on how trypanosomes adapt to and evade the host defence responses in the salivary glands. The research described aims to identify proteins involved in the mechanisms that facilitate infection

Studies on the DT-diaphorase-catalysed reaction employing quinones as substrates: evidence for a covalent modification of DT-diaphorase by tetrachloro-p-benzoquinone

In this study, the kinetic parameters, Vmax and Km, of rat liver DT-diaphorase were determined for a series of p-benzoquinones, with methyl, methoxy, cyano, hydroxy and halo substituents. The results show that there is no correlation between the experimentally determined rates of p-benzoquinone reduction by DT-diaphorase and the calculated chemical reactivity of the examined substrates as expressed by the energy of the lowest unoccupied molecular orbital, E(LUMO). However, a reasonable correlation was found between the natural logarithm of Vmax/Km and the partition coefficient of the p-benzoquinones (r=0.81). Furthermore, tetrachloro-p-benzoquinone, one of the tested quinones is shown to be an inhibitor of rat DT-diaphorase. The presence of bovine serum albumin (BSA) in the incubation mixture protects DT-diaphorase against the inactivation by tetrachloro-p-benzoquinone, probably by interacting with the quinone. Maldi-Tof analysis of the incubation mixture of the purified DT-diaphorase and tetrachloro-p-benquinone showed that every subunit of the enzyme shifted about +414 amu, whereas the dimer shifted about +849 amu relative to control values. This indicates a covalent modification of the rat liver DT-diaphorase by tetrachloro-p-benzoquinone

Syringa oblata Lindl var. alba as a source of oleuropein and related compounds

The leaf methanol extract of Syringa oblata Lindl var. alba was investigated as a source of oleuropein and related compounds. The extract had a high total phenol content and a radical scavenging activity similar to that of the respective extract from Olea europaea leaves. HPLC-DAD characterisation of the two most abundant phenolic compounds in the extract of S. oblata indicated that both had UV spectra matching that of oleuropein. The presence of oleuropein was verified by using LC-MS. Identification of the second compound was only feasible after isolation (preparative HPLC) and spectroscopic characterisation [LC-MS, 1H NMR and homonuclear two-dimensional correlated spectroscopy (COSY)]. The compound identified was the known bioactive syringopicroside. On the basis of MS data other peaks were assigned to oleuropein aglycone, verbascoside, ligstroside and syringopicroside derivatives, as well as to a luteolin rutinoside. The findings are promising for the potential exploitation of S. oblata leaf extract as a source for oleuropein and other bioactive ingredient

Perspective on calf and mammary gland development through changes in the bovine milk proteome over a complete lactation

Milk contains all the nutrients for the growth and development of the neonate. However, milk composition is not constant during lactation. To study the changes of the milk proteome over lactation, filter-aided sample preparation combined with dimethyl labeling followed by liquid chromatography tandem mass spectrometry was used to identify and quantify milk proteins from 4 cows. A total of 229 proteins were identified, of which 219 were quantified. An 80% overlap was found in identified and quantified proteins between the 4 individual cows during lactation. Over lactation, the number of quantified proteins changed slightly (less than 10%), whereas the concentration of proteins changed considerably. Transport proteins involved in lipid synthesis (fatty acid–binding protein, perilipin-2, butyrophilin) increased, whereas proteins related to cholesterol transport (apolipoprotein E) decreased. The changes of lipid synthesis proteins are in accordance with the increased milk fat yield over lactation, indicating the increase of de novo mammary fatty acid synthesis as lactation advances. The high abundance of immune-related proteins in early lactation indicates the important role of these proteins for immune system development of calves. The increase in immune-related proteins (immunoglobulins, osteopontin, lactoferrin) and the decrease of proteins related to milk component synthesis (a-lactalbumin, ß-lactoglobulin, fatty acid–binding protein, perilipin-2, butyrophilin) in late lactation can be associated with the protection of the mammary gland. In conclusion, the changes of proteins with different biological functions reflect not only the changing needs of calves but also the development and protection of the mammary gland over lactation

Bovine Milk Proteome in the First 9 Days: Protein Interactions in Maturation of the Immune and Digestive System of the Newborn

In order to better understand the milk proteome and its changes from colostrum to mature milk, samples taken at seven time points in the first 9 days from 4 individual cows were analyzed using proteomic techniques. Both the similarity in changes from day 0 to day 9 in the quantitative milk proteome, and the differences in specific protein abundance, were observed among four cows. One third of the quantified proteins showed a significant decrease in concentration over the first 9 days after calving, especially in the immune proteins (as much as 40 fold). Three relative high abundant enzymes (XDH, LPL, and RNASE1) and cell division and proliferation protein (CREG1) may be involved in the maturation of the gastro-intestinal tract. In addition, high correlations between proteins involved in complement and blood coagulation cascades illustrates the complex nature of biological interrelationships between milk proteins. The linear decrease of protease inhibitors and proteins involved in innate and adaptive immune system implies a protective role for protease inhibitor against degradation. In conclusion, the results found in this study not only improve our understanding of the role of colostrum in both host defense and development of the newborn calf but also provides guidance for the improvement of infant formula through better understanding of the complex interactions between milk proteins

A His-tag based immobilization method for the preparation and reconstitution of apoflavoproteins

The NifL PAS domain from Azotobacter vinelandii is a flavoprotein with FAD as the prosthetic group. Here we describe a novel immobilization procedure for the large-scale preparation of apo NifL PAS domain and its efficient reconstitution with either 2,4a-C-13-FAD or 2,4a-C-13-FMN. In this procedure, the His-tagged holoprotein is bound to an immobilized metal affinity column and the flavin is released by washing the column with buffer containing 2 M KBr and 2 M urea. The apoprotein is reconstituted on-column with the (artificial) flavin cofactor, and then eluted with buffer containing 250 mM imidazole. Alternatively, the immobilized apoprotein can be released from the column matrix before reconstitution. The His-tag based immobilization method of preparing reconstituted (or apo) NifL PAS domain protein has the advantage that it combines a protein affinity chromatography technique with limited protein loss, resulting in a high protein yield with extremely efficient flavin reconstitution. This on-column reconstitution method can also be used in cases where the apoprotein is unstable. Therefore, it may develop as a universal method for replacement of flavin or other cofactors. (C) 2002 Elsevier Science B.V. All rights reserved

Proteomic analysis of Chilo iridescent virus

In this first proteomic analysis of an invertebrate iridovirus, 46 viral proteins were detected in the virions of Chilo iridescent virus (CIV) based on the detection of 2 or more distinct peptides; an additional 8 proteins were found based on a single peptide. Thirty-six of the 54 identified proteins have homologs in another invertebrate and/or in one or more vertebrate iridoviruses. The genes for 5 of the identified proteins, 22L (putative helicase), 118L, 142R (putative RNaseIII), 274L (major capsid protein) and 295L, are shared by all iridoviruses for which the complete nucleotide sequence is known and may therefore be considered as iridovirus core genes. Three identified proteins have homologs only in ascoviruses. The remaining 15 identified proteins are so far unique to CIV. In addition to broadening our insight in the structure and assembly of CIV virions, this knowledge is pivotal to unravel the initial steps in the infection process