Structure and Function of the Plant Alternative Oxidase: Its Putative Role in the Oxygen Defence Mechanism

Current understanding of the structure and function of the plant alternative oxidase is reviewed. In particular, the role of the oxidase in the protection of tissues against oxidative stress is developed.     

A straightforward approach to isolate DNA sequences with potential linkage to the retinoblastoma locus

Summary From a human-Chinese hamster somatic cell hybrid a clone was derived containing chromosome 13 in duplicate as its only human material. This clone was used to construct a human chromosome 13-specific recombinant DNA-library. Overlapping Sau3AI DNA sequences (11.9–17.2 kb) from the cell hybrid were inserted into the lambda phage vector EMBL4. From eleven recombinants having a human insert thirteen putative unique DNA sequences were isolated and cloned into the plasmid vector pBR329. A human-mouse hybrid containing a human chromosome 13 with a deletion of 13q14 and lacking its undeleted homologue was constructed to be used in a selection procedure for DNA sequences belonging to band q14. Three probes originating from two different phages were assigned to 13q14 because they did not hybridise to DNA from this cell hybrid. One of these 13q14 probes detects a low frequency (2/44) Msp I restriction fragment length polymorphism. The probes are now being used for screening a cosmid library to find adjacent polymorphic sequences with a RFLP information content suitable for application in the diagnosis of hereditary retinoblastoma.Preliminary reports of these experiments were presented at the 8th International Workshop on Human Gene Mapping, Helsinki, August 4–10, 1985, and the 13th International Congress of Biochemistry, Amsterdam, August 25–30, 1985 (Scheffer et al. 1985a,b)     

Regional LCA in a global perspective. A basis for spatially differentiated environmental life cycle assessment

Background, aim and scope  

In the context of environmental life cycle assessment (LCA), life cycle impact assessment (LCIA) is one of the central issues with respect to modelling and methodological data collection. The thesis described in this paper focusses on the assessment of toxicity-related impacts, and on the collection of normalisation data. A view on the complementary roles of LCA toxicity assessment on the one hand and human and environmental risk assessment (HERA) on the other is presented, and the global, spatially differentiated LCA toxicity assessment model GLOBOX for the assessment of organics and metals is described. Normalisation factors for the year 2000 are calculated on a global as well as on a European level.     

Microbial engineering of dehydro-amino acids and lanthionines in non-lantibiotic peptides

This minireview focusses on the use of bacteria to introduce dehydroresidues and (methyl)lanthionines in (poly)peptides. It mainly describes the broad exploitation of bacteria containing lantibiotic enzymes for the engineering of these residues in a wide variety of peptides in particular in peptides unrelated to lantibiotics. Lantibiotic dehydratases dehydrate serines and threonines present in peptides preceded by a lantibiotic leader peptide thus forming dehydroalanine and dehydrobutyrine, respectively. These dehydroresidues can be coupled to cysteines thus forming (methyl)lanthionines. This coupling is catalysed by lantibiotic cyclases. The design, synthesis, and export of microbially engineered dehydroresidue and or lanthionine-containing peptides in non-lantibiotic peptides are reviewed, illustrated by some examples which demonstrate the high relevance of these special residues. This minireview is the first with special focus on the microbial engineering of nonlantibiotic peptides by exploiting lantibiotic enzymes.     

Functional approach based on morphology as a model of phytoplankton variability in a subtropical floodplain lake: a long-term study

Long-term phytoplankton dynamics in a floodplain lake, between periods of limnophase and potamophase was studied using the morphology-based functional classification (MBFG). The work was carried out to test the hypothesis that the temporal distribution of MBFGs is influenced by the hydrosedimentological regime of the Paraná River, and that these differences can be registered by analyzing the dominant MBFGs in the two periods. Samples were taken in an isolated floodplain lake on the Upper Paraná River floodplain, Brazil, from 2000 to 2012, and water level, water temperature, conductivity, pH, dissolved-oxygen, euphotic zone, maximum depth, and nutrients were used to explain the distribution of MBFGs. 478 taxa were identified and distributed in seven MBFGs (I–VII). MBFG V (flagellates algae) and VI (diatoms) showed 100% frequency of occurrence. MBFG II was associated exclusively with the limnophase; MBFG IV and VII were associated with limnophase periods with higher pH and dissolved-oxygen content; and MBFG I, III, V, and VI were associated with limnophase and potamophase, mainly associated with transparency, nutrients, and conductivity. The MBFG approach represented the trends of each group in terms of its occurrence and biovolume, according to the hydrosedimentological regime, providing broad-scale information on changes in the phytoplankton.     

Disruption of sexual communication in the mirid bug Lygocoris pabulinus by hexyl butanoate

1 The metathoracic scent gland in Lygocoris pabulinus contains mostly hexyl butanoate. As secretions of this gland in Heteroptera may serve as an alarm pheromone, we determined whether hexyl butanoate is released by disturbed bugs, and whether this compound disrupts sexual attraction of L. pabulinus males towards females. 2 Undisturbed males and females, and disturbed males released less than 100 ng/h hexyl butanoate, whereas disturbed females released a highly variable amount, ranging from 25 ng/h to more than 1 μg/h. 3 In the field, traps with virgin females and rubber septa containing 20 mg hexyl butanoate, caught a total of one male in a month. In control traps without hexyl butanoate, 36 males were caught in the same period. 4 In Y‐track olfactometer tests, males were not attracted to virgin females when a dispenser with 20 mg hexyl butanoate was placed in the bottle with females. Males were attracted to females when the dispenser was placed downwind from the females, but upwind from the point of male release. 5 These results suggest that males are not repelled by hexyl butanoate, but that this compound inhibits sex pheromone release in females. Application possibilities for pest management are discussed.     

TLR-3 is Present in Human Adipocytes,but Its Signalling is Not Required for Obesity-Induced Inflammation in Adipose Tissue In Vivo

Innate immunity plays a pivotal role in obesity-induced low-grade inflammation originating from adipose tissue. Key receptors of the innate immune system including Toll-like receptors-2 and -4 (TLRs) are triggered by nutrient excess to promote inflammation. The role of other TLRs in this process is largely unknown. In addition to double-stranded viral mRNA, TLR-3 can also recognize mRNA from dying endogenous cells, a process that is frequently observed within obese adipose tissue. Here, we identified profound expression of TLR-3 in adipocytes and investigated its role during diet-induced obesity. Human adipose tissue biopsies (n=80) and an adipocyte cell-line were used to study TLR-3 expression and function. TLR-3-/- and WT animals were exposed to a high-fat diet (HFD) for 16 weeks to induce obesity. Expression of TLR-3 was significantly higher in human adipocytes compared to the non-adipocyte cells part of the adipose tissue. In vitro, TLR-3 expression was induced during differentiation of adipocytes and stimulation of the receptor led to elevated expression of pro-inflammatory cytokines. In vivo, TLR-3 deficiency did not significantly influence HFD-induced obesity, insulin sensitivity or inflammation. In humans, TLR-3 expression in adipose tissue did not correlate with BMI or insulin sensitivity (HOMA-IR). Together, our results demonstrate that TLR-3 is highly expressed in adipocytes and functionally active. However, TLR-3 appears to play a redundant role in obesity-induced inflammation and insulin resistance.     

Identification of Regions Critical for the Integrity of the TSC1-TSC2-TBC1D7 Complex

The TSC1-TSC2-TBC1D7 complex is an important negative regulator of the mechanistic target of rapamycin complex 1 that controls cell growth in response to environmental cues. Inactivating TSC1 and TSC2 mutations cause tuberous sclerosis complex (TSC), an autosomal dominant disorder characterised by the occurrence of benign tumours in various organs and tissues, notably the brain, skin and kidneys. TBC1D7 mutations have not been reported in TSC patients but homozygous inactivation of TBC1D7 causes megaencephaly and intellectual disability. Here, using an exon-specific deletion strategy, we demonstrate that some regions of TSC1 are not necessary for the core function of the TSC1-TSC2 complex. Furthermore, we show that the TBC1D7 binding site is encoded by TSC1 exon 22 and identify amino acid residues involved in the TSC1-TBC1D7 interaction.