Chitin-binding proteins in invertebrates and plants comprise a common chitin-binding structural motif

Tachycitin, a 73-residue polypeptide having antimicrobial activity is present in the hemocyte of horseshoe crab (Tachypleus tridentatus). The first three-dimensional structure of invertebrate chitin-binding protein was determined for tachycitin using two-dimensional nuclear magnetic resonance spectroscopy. The measurements indicate that the structure of tachycitin is largely divided into N- and C-terminal domains; the former comprises a three-stranded beta-sheet and the latter a two-stranded beta-sheet following a short helical turn. The latter structural motif shares a significant tertiary structural similarity with the chitin-binding domain of plant chitin-binding protein. This result is thought to provide faithful experimental evidence to the recent hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.     

Carbohydrate-binding proteins of marine invertebrates

The information on the carbohydrate specificity and molecular organization of some carbohydrate-binding proteins (lectins) of marine invertebrates is reported. Antiviral activity of some of the lectins against human immunodeficiency virus has been studied. Lectins of marine invertebrates are promising tools for studying natural glycoconjugates and cell effectors in vitro.     

Carbohydrate-binding proteins of marine invertebrates

The information on the carbohydrate specificity and molecular organization of some carbohydrate-binding proteins (lectins) of marine invertebrates is reported. Antiviral activity of some of the lectins against human immunodeficiency virus has been studied. Lectins of marine invertebrates are promising tools for studying natural glycoconjugates and cell effectors in vitro.     

Glycosylation of lens proteins in senile cataract and diabetes mellitus

We have investigated glycosylation of lens proteins in diabetic and non-diabetic senile cataract patients. Our study reveals that glycosylation of lens cortical proteins, but not of nuclear proteins, is significantly higher in diabetic patients with senile cataract. This finding serves to clarify the confusion over glycosylation of lens proteins as it relates to diabetes mellitus and further contributes to an understanding of glycosylation of lens tissues as a distinct posttranslational modification.     

Glycosylation of hepatitis C virus envelope proteins

Enveloped viruses are surrounded by a membrane derived from the host-cell that contains proteins called "envelope proteins". These proteins play a major role in virus assembly and entry. In most of the enveloped viruses, they are modified by N-linked glycosylation which is supposed to play a role in their stability, antigenicity and biological functions. Glycosylation is also known to play a major role in the biogenesis of proteins by being directly and/or indirectly involved in protein folding. Recent studies on hepatitis C virus (HCV) envelope proteins have revealed a complex interplay between cleavage by signal peptidase, folding and glycosylation. The knowledge that has been accumulated on the early steps of glycosylation of these proteins is presented in this review.     

Shading effects of free-floating plants on drainage-ditch invertebrates

In small, lentic ecosystems in agricultural areas, eutrophication often results in excessive growth of small, free-floating plants. A dense layer of plants on the water surface changes the underwater light climate drastically and in turn leads to hypoxic or even anoxic conditions. Knowledge of the effects on macroinvertebrates of reduced light conditions and oxygen stress as result of eutrophication is limited. We thus examined in a field situation the influence of an unpredictable, 10-day period of low oxygen availability as a result of poor underwater light conditions. In a before–after control–impact design, the underwater light climate and dissolved oxygen concentration of ditch sections were manipulated, and the macroinvertebrate assemblage composition was recorded during the 4 weeks before and after treatment. A poor underwater light climate in combination with normoxic conditions did not affect the invertebrate assemblage composition, but the combination of low-light intensity and anoxic conditions did alter it. Interestingly, these changes were not apparent directly after treatment but developed in the weeks following, indicating that although the invertebrates could cope with a shading-induced period of hypoxia, costs were associated with the event over a longer time period.     

Glycosylation control technologies for recombinant therapeutic proteins

Protein glycosylation is a very important quality attribute of any biopharmaceutical product as it affects the efficacy, serum half-life, and antigenicity of a molecule. The present expression hosts commercially utilized for a recombinant glycoprotein production generally cannot produce a desired and uniform glycan composition and generally exhibit non-human glycans that can lead to unwanted side effects. The authors provide a comprehensive review of various approaches which can be implemented to minimize the glycan heterogeneity for the production of the desired protein with improved glycoforms. The authors also describe that the industry standard expression systems such as mammalian, insect, and yeast are glycoengineered to produce human-like glycan composition of a recombinant product. This review summarizes the recent technologies used for the improvement of the glycan composition of the biotherapeutics, focusing largely on the selection of an appropriate expression host, glycoengineering, and upstream process optimization to control protein glycosylation and thus enhanced biological activity with fewer side effects. Here, we also suggest various approaches such as host and clone selection to achieve expected glycosylation in a recombinant protein. The cell culture, biochemical, and physical process parameters play a key role in the manufacturing of the desired glycoform of a therapeutic protein. Hence, these components are to be considered very carefully while developing such glycoproteins. Also, glycoengineering of production host to modulate the protein glycosylation is also recommended in the present review.

     

Crayfish invasion facilitates dispersal of plants and invertebrates by gulls

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A novel family of single VWC-domain proteins in invertebrates

Using a combination of sequence analysis tools, a novel family of 13 short Drosophila melanogaster proteins with similarity to a single von Willebrand factor C-domain (SVC proteins) has been identified. SVCs are predicted to be secreted and a structural model for the family is proposed, using a known von Willebrand factor C-domain (VWC) structure as template. All SVCs possess eight cysteines, consistent with the loss of one bonded pair from the 10-cysteine canonical pattern of most VWC domains. Unlike most Drosophila genes, many SVCs are not expressed during development, and misexpression has no apparent effect on development or viability. SVCs appear to be restricted to arthropods. A role for SVCs in response to environmental challenges is proposed.     

The potential role of waterbirds in dispersing invertebrates and plants in arid Australia

1. The role of waterbirds as vectors of plants and invertebrates within and between arid‐zone wetlands is poorly understood. We present the first detailed study of passive dispersal by nomadic birds in Australasia. We investigated the numbers and types of invertebrate and plant propagules within freshly collected faecal samples as well as their viability. We compared dispersal among Grey Teal (Anas gracilis), Eurasian Coot (Fulica atra) and Black Swan (Cygnus atratus) in the Macquarie Marshes, a complex of temporary to semi‐permanent wetlands in New South Wales. 2. When faecal samples (n = 60) were inundated in the laboratory and monitored over 3 weeks, ciliates (75% of samples), nematodes (22%), ostracods (13%) and rotifers (5%) were recorded, with higher taxon richness in coot samples. Faecal samples (n = 71) were also sieved to quantify intact propagules, and ostracod eggs (70% of samples), large branchiopod eggs (31%) and bryozoan statoblasts (31%) were the most abundant invertebrates. Diaspores of 19 plant taxa were recorded, 14 of which were germinated in the laboratory or shown to be viable at the end of germination trials. The abundance and diversity of invertebrate propagules was highest in coot samples, whereas the abundance and diversity of diaspores was highest in teal samples. 3. One Australian Pelican (Pelecanus conspicillatus) sample was obtained and found to contain more taxa and far more propagules than any sample from other waterbirds, suggesting that piscivorous birds might have an important role in the indirect dispersal of propagules ingested by fish. 4. Our results support a role for birds in explaining the distributions of cosmopolitan plant genera such as Lemna, Typha, Myriophyllum and Nitella. The alien plants Ranunculus sceleratus, Medicago polymorpha and Polygonum arenastrum were recorded, demonstrating the potential role of waterfowl in the spread of exotic species. As the frequency and duration of flooding of arid‐zone wetlands decreases owing to human activities, the importance of waterbirds in facilitating recolonisation of temporary wetlands is likely to increase.     

A monoclonal antibody that detects vimentin-related proteins in invertebrates

Summary Drosophila melanogaster contains a 46 000 MW cytoplasmic protein which is immunologically related to the intermediate filament protein vimentin of vertebrates. A monoclonal antibody raised against this protein was used to study its cross-reactivity with other vertebrate and invertebrate cells. Indirect immunofluorescence showed filamentous meshworks in all species tested. Protein blotting was used to determine the molecular weights of the proteins responsible for the wide range of cross-reactivity of this antibody. We present evidence that vimentin-like proteins are also present in invertebrates and form a cytoplasmic network in Paramecium. Furthermore, we demonstrate in vertebrates and invertebrates the presence of high molecular weight polypeptides which are immunologically related to vimentin.     

Stress proteins in plants

Summary

Several environmental stresses elicit specific plant genomic responses. These include temperature extremes, oxidative stress, water stress, anaerobiosis as well as pathogen attack. Molecular biological approaches are now yielding insights into the mechanisms whereby plant cells perceive the stress of temperature extremes and activate their defences in response at the gene level. These responses appear to be interconnected with responses to oxidative stress in plants and an outcome is a greater appreciation of the role, and the genetic regulation, of two important groups of ‘stress proteins’, namely the heat shock proteins and the antioxidant enzymes.     

Glycosylation of endogenous proteins through dolichol derivatives in reticulocyte plasma membranes

It has been found that rabbit reticulocyte plasma membranes contain the enzymatic activities responsible for the synthesis of all the polyprenol-bound sugars that are intermediates in the glycosylation of proteins. The final reaction in which an oligosaccharide is transferred from a dolichol pyrophosphate derivative to an endogenous protein was detected in reticulocyte but not in erythrocyte plasma membranes.