Calcium and Microorganisms

Abstract

This review followed from experiments suggesting that some fungi do not require calcium. It was found that many studies of a calcium requirement in microorganisms had assumed specificity for chelation agents such as EGTA and A23187, which the reagents did not possess. Early studies still cited today often preceded the recognition that microorganisms required manganese and zinc. As a result of both of these misunderstandings, there was rarely any attempt to replace calcium by other important trace elements. In some studies that seem to have been overlooked, the apparent requirement for calcium depended on the growth conditions used. Escherichia coli, Neurospora crassa, and Saccharomyces cerevisiae were then selected for detailed consideration and it is concluded that further experiments are needed before the involvement of calcium is proved.

CcbP, a calcium-binding protein from Anabaena sp. PCC 7120, provides evidence that calcium ions regulate heterocyst differentiation

“…The intracellular free calcium ion concentration {[Ca 2ϩ ] i } is tightly regulated through Ca 2ϩ channels, Ca 2ϩ pumps, and Ca 2ϩ -binding proteins, and [Ca 2ϩ ] i is generally maintained in the nanomolar range. In bacteria, the role of Ca 2ϩ in cellular activities is less clear (3)(4)(5). It has been demonstrated that [Ca 2ϩ ] i is tightly regulated in some bacteria (6), and there is evidence indicating that calcium is critical to some bacterial cellular processes such as sporulation of Bacillus (7), chemotaxis of Escherichia coli (8), and heterocyst differentiation of cyanobacteria (9).…”

A Homolog of Mammalian, Voltage-Gated Calcium Channels Mediates Yeast Pheromone-Stimulated Ca2+ Uptake and Exacerbates the cdc1(Ts) Growth Defect

“…Among the best characterized of these entry pathways are the voltage-dependent Ca 2ϩ channels of the plasma membrane which open in response to membrane depolarization (3,9). Ca 2ϩ has been implicated in numerous processes of the budding yeast Saccharomyces cerevisiae (8,16,20,37), including stress-induced expression of ion transporter genes, bud formation, and viability upon pheromone-induced arrest. However, there is compelling evidence for a role for Ca 2ϩ in only the last of these processes (7,15,16,22).…”

Regulation of intracellular free calcium concentration during heterocyst differentiation by HetR and NtcA in Anabaena sp. PCC 7120

“…The DNA bands after polyacrylamide gel (6%) electrophoresis were visualized by x-ray films (Kodak). To confirm whether the sequence GTN 11 ACA in the ccbP promoter region was required for NtcA binding, EMSA was performed with two synthetic DNA fragments based on the DNA sequence from nucleotides Ϫ179 to Ϫ130 upstream of the start codon of the ccbP gene. The GTN 11 ACA sequence was changed to CCN 11 CCC in one of the fragments.…”

“…To confirm whether the sequence GTN 11 ACA in the ccbP promoter region was required for NtcA binding, EMSA was performed with two synthetic DNA fragments based on the DNA sequence from nucleotides Ϫ179 to Ϫ130 upstream of the start codon of the ccbP gene. The GTN 11 ACA sequence was changed to CCN 11 CCC in one of the fragments. Coexpression of the ntcA of Anabaena 7120 and gfp was carried out by transformation of E. coli strain BL21(DE3) with pET-ntcA or pET-psaE (29), both of which confer resistance of ampicillin, and pPccbP-gfp, which contains the gfp gene under control of the ccbP promoter (10) and confers resistance to kanamycin, with selection on ampicillin and kanamycin.…”

“…It is known that Ca 2ϩ ions play very important roles in cellular processes in eukaryotes and that eukaryotic [Ca 2ϩ ] i is tightly regulated and maintained in the nanomolar range. Although the role of Ca 2ϩ in prokaryotic cellular activities is less clear (11)(12)(13), current evidence also shows that [Ca 2ϩ ] i is also tightly regulated in bacteria (14,15) and that Ca 2ϩ plays important roles in bacterial cell differentiation such as sporulation of Bacillus (16) and heterocyst formation of cyanobacteria (10). It was recently shown that [Ca 2ϩ ] i increases in differentiating cells after transfer from a nitrogen-replete condition to a nitrogen-deprived condition (10).…”