Efficacy and deficiencies of rapid biomonitoring in biodiversity conservation: a case study in South Africa

Rapid biomonitoring protocols, using biotic indices based on macroinvertebrate diversity to assess river ecosystem health, are widely used globally. Such quick assessment techniques are lauded for the rapid results obtained and the relatively easy protocol used to achieve an answer. However, do such quick assessments of water quality give enough information about ecosystems? Are important details being overlooked? When should a full faunal survey be used in preference? Important research programmes, including environmental impact studies, often misuse biomonitoring techniques, making influential management decisions using superficial, low-level data obtained using biomonitoring tools, inappropriate to address those management objectives. The value of using biomonitoring as a quick tool, versus a more detailed faunal assessment, is considered here. The assessment of teloganodid mayfly fauna occurring in South African rivers provides an example of the value of detailed studies versus superficial family level investigations, showing that a rapid biomonitoring approach should not be used as a shortcut when a more detailed survey is needed. Each situation should be assessed for its own merit in a given set of project circumstances. A checklist of criteria is presented, giving guidance on when rapid biomonitoring alone is valuable and when more detailed assessments would give a more relevant result.     

Purification and partial characterization of hyaluronidase from stonefish (Synanceja horrida) venom.

1. A marine hyaluronidase was purified 261-fold from the stonefish (Synanceja horrida) crude venom using Sephacryl S-200 HR and heparin affinity-gel chromatography. 2. Stonefish hyaluronidase has a pI of 9.2, a mol. wt of 62,000 and it was purified to a very high spec. act. of 1.6 x 10(6) NFU/mg protein. 3. It was heat sensitive and was inhibited by Cu2+, Hg2+ and heparin. 4. Stonefish hyaluronidase did not contain any haemorrhagic or lethal activity. 5. The N-terminal sequence of stonefish hyaluronidase has been determined to be A-P-S-X-D-E-G-N-K-K-A-D-N-L-L-V-K-K-I-N.     

Germline genome modification through novel political,ethical, and social lenses

Much has been written about gene modifying technologies (GMTs), with a particularly strong focus on human germline genome editing (HGGE) sparked by its unprecedented clinical research application in 2018, shocking the scientific community. This paper applies political, ethical, and social lenses to aspects of HGGE to uncover previously underexplored considerations that are important to reflect on in global discussions. By exploring 4 areas—(1) just distribution of HGGE benefits through a realist lens; (2) HGGE through a national interest lens; (3) “broad societal consensus” through a structural injustice lens; and (4) HGGE through a scientific trustworthiness lens—a broader perspective is offered, which ultimately aims to enrich further debates and inform well-considered solutions for developments in this field. The application of these lenses also brings to light the fact that all discussions about scientific developments involve a conscious or unconscious application of a lens that shapes the direction of our thinking.     

Mechanism for phenol tolerance in phenol-degrading Comamonas testosteroni strain

Comamonas testosteroni P15 and its mutant strain E23 can tolerate and utilize phenol as the sole source of carbon and energy at up to 15 mM and 20 mM, respectively. Compared to the wild type P15, mutant E23 showed higher values of K _s and K _i but a lower μ_max value, and had lower phenol hydroxylase and catechol 2,3-dioxygenase activities. Without phenol exposure, mutant E23 demonstrated a two-fold greater amount of cardiolipin than the wild type P15. Upon exposure to phenol, an increase in cardiolipin at the expense of phosphatidylethanolamine was observed in the wild type P15. However, there was no significant difference in major phospholipid contents between mutant E23 cells grown in the presence or absence of phenol. It was noted that the ratio of trans/cis fatty acids of phosphatidylethanolamine and cardiolipin in mutant E23 was 65–70% higher than that in the wild type P15. In the absence of phenol, the degree of saturation of cardiolipin in mutant E23 was 33% higher than that in wild type P15. In contrast to earlier findings, an increase in C16:1 9trans with a simultaneous decrease in C18:1 11cis instead of C16:1 9cis was observed in specific classes of phospholipids. Received: 30 July 1998 / Received last revision: 16 November 1998 / Accepted: 12 December 1998     

A synthetic weak neurotoxin binds with low affinity to Torpedo and chicken alpha7 nicotinic acetylcholine receptors.

Weak neurotoxins from snake venom are small proteins with five disulfide bonds, which have been shown to be poor binders of nicotinic acetylcholine receptors. We report on the cloning and sequencing of four cDNAs encoding weak neurotoxins from Naja sputatrix venom glands. The protein encoded by one of them, Wntx-5, has been synthesized by solid-phase synthesis and characterized. The physicochemical properties of the synthetic toxin (sWntx-5) agree with those anticipated for the natural toxin. We show that this toxin interacts with relatively low affinity (K(d) = 180 nm) with the muscular-type acetylcholine receptor of the electric organ of T. marmorata, and with an even weaker affinity (90 microm) with the neuronal alpha7 receptor of chicken. Electrophysiological recordings using isolated mouse hemidiaphragm and frog cutaneous pectoris nerve-muscle preparations revealed no blocking activity of sWntx-5 at microm concentrations. Our data confirm previous observations that natural weak neurotoxins from cobras have poor affinity for nicotinic acetylcholine receptors.     

Biophysical Studies of Bacterial Topoisomerases Substantiate Their Binding Modes to an Inhibitor

Bacterial DNA topoisomerases are essential for bacterial growth and are attractive, important targets for developing antibacterial drugs. Consequently, different potent inhibitors that target bacterial topoisomerases have been developed. However, the development of potent broad-spectrum inhibitors against both Gram-positive (G⁺) and Gram-negative (G⁻) bacteria has proven challenging. In this study, we carried out biophysical studies to better understand the molecular interactions between a potent bis-pyridylurea inhibitor and the active domains of the E-subunits of topoisomerase IV (ParE) from a G⁺ strain (Streptococcus pneumoniae (sParE)) and a G⁻ strain (Pseudomonas aeruginosa (pParE)). NMR results demonstrated that the inhibitor forms a tight complex with ParEs and the resulting complexes adopt structural conformations similar to those observed for free ParEs in solution. Further chemical-shift perturbation experiments and NOE analyses indicated that there are four regions in ParE that are important for inhibitor binding, namely, α2, the loop between β2 and α3, and the β2 and β6 strands. Surface plasmon resonance showed that this inhibitor binds to sParE with a higher K_D than pParE. Point mutations in α2 of ParE, such as A52S (sParE), affected its binding affinity with the inhibitor. Taken together, these results provide a better understanding of the development of broad-spectrum antibacterial agents.     

Tn5563, a transposon encoding putative mercuric ion transport proteins located on plasmid pRA2 of Pseudomonas alcaligenes

Sequence analysis of pRA2, an endogenous 33-kb plasmid from Pseudomonas alcaligenes NCIB 9867 (strain P25X), revealed the presence of a 6256-bp transposon of the Tn3 family, designated Tn5563. Tn5563, which is flanked by two 39-bp inverted repeats, encodes a transposase, a resolvase, and two open reading frames which share amino acid sequence similarities with the mercuric ion transport proteins MerT and MerP encoded by several mer operons. However, no other mer operon genes were found on Tn5563. Sequencing of a RP4::Xln hybrid plasmid indicates possible interactions between pRA2 and the P25X chromosome mediated by Tn5563.     

Liposome-based vascular endothelial growth factor-165 transfection with skeletal myoblast for treatment of ischaemic limb disease

The study aims to use cholesterol (Chol) + DOTAP liposome (CD liposome) based human vascular endothelial growth factor-165 (VEGF(165)) gene transfer into skeletal myoblasts (SkMs) for treatment of acute hind limb ischaemia in a rabbit model. The feasibility and efficacy of CD liposome mediated gene transfer with rabbit SkMs were characterized using plasmid carrying enhanced green fluorescent protein (pEGFP) and assessed by flow cytometry. After optimization, SkMs were transfected with CD lipoplexes carrying plasmid-VEGF(165) (CD-pVEGF(165)) and transplanted into rabbit ischaemic limb. Animals were randomized to receive intramuscular injection of Medium199 (M199; group 1), non-transfected SkM (group 2) or CD-pVEGF(165) transfected SkM (group 3). Flow cytometry revealed that up to 16% rabbit SkMs were successfully transfected with pEGFP. Based on the optimized transfection condition, transfected rabbit SkM expressed VEGF(165) up to day 18 with peak at day 2. SkMs were observed in all cell-transplanted groups, as visualized with 6-diamidino-2-phenylindole and bromodeoxyuridine. Angiographic blood vessel score revealed increased collateral vessel development in group 3 (39.7 +/- 2.0) compared with group 2 (21.6 +/- 1.1%, P < 0.001) and group 1 (16.9 +/- 1.1%, P < 0.001). Immunostaining for CD31 showed significantly increased capillary density in group 3 (14.88 +/- 0.9) compared with group 2 (8.5 +/- 0.49, P < 0.001) and group 1 (5.69 +/- 0.3, P < 0.001). Improved blood flow (ml/min./g) was achieved in animal group 3 (0.173 +/- 0.04) as compared with animal group 2 (0.122 +/- 0.016; P= 0.047) and group 1 (0.062 +/- 0.012; P < 0.001). In conclusion, CD liposome mediated VEGF(165) gene transfer with SkMs effectively induced neovascularization in the ischaemic hind limb and may serve as a safe and new therapeutic modality for the repair of acute ischaemic limb disease.