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.     

Haemoglobin Camperdown beta104(G6) arginine leads to serine.

Routine investigation of ante natal patients revealed a subtle change in the electrophoretic pattern on cellulose acetate of the proposita. Further investigations by isoelectric focussing in polyacrylamide gel suggested the presence of two major haemoglobin components. Using a modified cellulose acetate technique globin chain separation revealed an abnormal beta-chain. Chain separation on a carboxymethyl-cellulose column provided a pure sample of the abnormal beta-chain. After amino-ethylation, tryptic digestion and peptide mapping, amino acid analysis of relevant peptides showed the abnormality in the beta-chain to be a substitution of arginine by serine at the 104 position. The presence of a positively charged residue at this position would appear to be necessary for the stabilization of the haemoglobin central cavity. The replacement by serine in this haemoglobin leads to slightly decreased stability but does not appear to affect the oxygen affinity.     

Globin genes in Polynesians have many rearrangements including a recently described gamma gamma gamma gamma/.

Rearrangements involving genes of the alpha- and beta-globin loci were frequently detected in DNA from Polynesians. A founder effect and genetic drift occurring 2,000-3,000 years ago as Polynesians migrated eastward across the Pacific is proposed as the likely mechanism for these genetic changes that include deletions or additions of alpha-, gamma-, and zeta-globin genes and an unusual restriction fragment length polymorphism (RFLP) associated with the zeta gene. Preliminary data show different frequencies for gene rearrangements between island groups. Further study of these differences should provide additional information on the prehistory of Polynesians.     

Mutational analysis of the receptor-activating region of human parathyroid hormone.

The first 4 residues of parathyroid hormone (PTH) are highly conserved in evolution and are important for biological activity. We randomly mutated codons 1-4 of human PTH (hPTH) with degenerate oligonucleotides and, after expression in COS cells, screened the mutants for receptor binding and cAMP-stimulating activity using ROS 17/2.8 cells. This survey identified Glu4 and Val2 as important determinants of receptor binding and activation, respectively. Positions 1 and 3 were more tolerant of substitutions indicating that these sites are less vital to hormone function. Activities of synthetic hPTH(1-34) analogs further demonstrated the importance of positions 2 and 4. The binding affinity of [Ala4,Tyr34] hPTH(1-34)NH2 was 100-fold reduced relative to [Tyr34]hPTH(1-34)NH2 (Kd values = 653 +/- 270 and 4 +/- 1 nM, respectively), and [Arg2, Tyr34]hPTH(1-34)NH2 was a weak partial agonist which bound well to the ROS cell receptor (Kd = 31 +/- 10 nM). The Arg2 analog was nearly as potent as PTH(3-34) as an in vitro PTH antagonist in osteoblast derived cells. However, unlike PTH(3-34), [Arg2]PTH was a full agonist in opossum kidney (OK) cells. These observations suggest that the activation domains of the OK and ROS cell PTH receptors are different. Thus, amino-terminal PTH analogs may be useful as probes for distinguishing properties of PTH receptors.     

Full-length chicken parathyroid hormone. Biosynthesis in Escherichia coli and analysis of biologic activity.

Chicken parathyroid hormone (cPTH) has been reported to stimulate adrenal steroidogenesis and to have unusual potency on traditional PTH target tissues. To evaluate these properties, chicken PTH-(1-88) has been expressed in Escherichia coli using a plasmid encoding a fusion protein which links together growth hormone, a factor Xa recognition site, and chicken PTH-(1-88). The growth hormone-cPTH fusion protein required the presence of 0.02% sodium dodecyl sulfate to remain in solution and be cleaved by factor Xa. The high performance liquid chromatography-purified recombinant cPTH-(1-88) and chemically synthesized cPTH-(1-34) had similar potency in rat osteosarcoma (ROS 17/2.8) cells, opossum kidney (OK) cells, and dispersed primary chicken kidney cells. The biologic potencies of cPTH-(1-34) and cPTH-(1-88) in radioreceptor binding and cAMP generation in both bone- and kidney-derived cell lines were less than those of human (h)PTH-(1-34). In dispersed chicken kidney cells, cAMP production by cPTH-(1-34) and cPTH-(1-88) was similar to that stimulated by human PTH-(1-34). No stimulation of steroidogenesis could be detected when recombinant chicken PTH-(1-88) was added to dispersed chicken adrenal cells. The biologic activity of recombinant chicken PTH-(1-88) purified from E. coli was comparable with that of chicken PTH-(1-88) expressed by mammalian COS cells. Thus, the full-length chicken PTH did not exhibit enhanced potency, when compared with human PTH in ROS 17/2.8, OK cell lines, and dispersed chicken kidney cells and did not demonstrate the novel steroidogenic action previously reported in adrenal cells. The successful production of chicken PTH-(1-88) will enhance our understanding of the structure-activity relationships for PTH, particularly the sequence-dependent metabolism of the hormone.