Finding divergent sequences of homomorphic sex chromosomes via diploidized nanopore-based assembly from a single male

Although homomorphic sex chromosomes can have non-recombining regions with elevated sequence divergence between its complements, such divergence signals can be difficult to detect bioinformatically. If found in genomes of e.g. insect pests, these sequences could be targeted by the engineered genetic sexing and control systems. Here, we report an approach that can leverage long-read nanopore sequencing of a single XY male to identify divergent regions of homomorphic sex chromosomes. Long-read data are used for de novo genome assembly that is diploidized in a way that maximizes sex-specific differences between its haploid complements. We show that the correct assembly phasing is supported by the mapping of nanopore reads from the male's haploid Y-bearing sperm cells. The approach revealed a highly divergent region (HDR) near the centromere of the homomorphic sex chromosome of Aedes aegypti, the most important arboviral vector, for which there is a great interest in creating new genetic control tools. HDR is located ~5Mb downstream of the known male-determining locus on chromosome 1 and is significantly enriched for ovary-biased genes. While recombination in HDR ceased relatively recently (~1.4 MYA), HDR gametologs have divergent exons and introns of protein coding genes, and most lncRNA genes became X-specific. Megabases of previously invisible sex-linked sequences provide new putative targets for engineering the genetic systems to control this deadly mosquito. Broadly, our approach expands the toolbox for studying cryptic structure of sex chromosomes.

De novo circular genome assembly of Elizabethkingia anophelis found in the mosquito Aedes aegypti from an Australian colony

We report the complete circular genome assembly of Elizabethkingia anophelis (Flavobacteriales) generated with the ONT and Illumina sequences from a laboratory-reared Aedes aegypti mosquito. This genome sequence does not belong to the lineage of known isolates from Anopheles mosquitoes, indicating that E. anophelis is genomically diverse across mosquito disease vectors.

Genomic resources for population analyses of an invasive insect pest Oryctes rhinoceros

Over the last few years, various types of NGS data have been accumulating for the coconut rhinoceros beetle (CRB, Oryctes rhinoceros), reflecting the growing interest in curtailing this invasive pest of palm trees. Whilst reference-free analyses of RNA-seq and RAD-seq datasets have been done for different CRB collections, recent availability of the CRB's genome assembly provides an opportunity to collate diverse data and create a reference-based population dataset. Here, I release such a dataset containing 6,725,935 SNPs and genotypes called across 393 individual samples from 16 populations, using the previously published raw sequences generated in 9 different experiments (RAD-Seq, RNA-Seq, WGS). I also provide reference-based datasets for the CRB's mitochondrial variants and for variants of its viral biocontrol agent Oryctes rhinoceros nudivirus. SNP data provide high resolution for determining the geographic origin of invasive CRB. With these genomic resources, new data can be analysed without re-processing the published samples and then integrated to expand the reference datasets.

A high-quality de novo genome assembly based on nanopore sequencing of a wild-caught coconut rhinoceros beetle (Oryctes rhinoceros)

Background

An optimal starting point for relating genome function to organismal biology is a high-quality nuclear genome assembly, and long-read sequencing is revolutionizing the production of this genomic resource in insects. Despite this, nuclear genome assemblies have been under-represented for agricultural insect pests, particularly from the order Coleoptera. Here we present a de novo genome assembly and structural annotation for the coconut rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), based on Oxford Nanopore Technologies (ONT) long-read data generated from a wild-caught female, as well as the assembly process that also led to the recovery of the complete circular genome assemblies of the beetle’s mitochondrial genome and that of the biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). As an invasive pest of palm trees, O. rhinoceros is undergoing an expansion in its range across the Pacific Islands, requiring new approaches to management that may include strategies facilitated by genome assembly and annotation.

Results

High-quality DNA isolated from an adult female was used to create four ONT libraries that were sequenced using four MinION flow cells, producing a total of 27.2 Gb of high-quality long-read sequences. We employed an iterative assembly process and polishing with one lane of high-accuracy Illumina reads, obtaining a final size of the assembly of 377.36 Mb that had high contiguity (fragment N50 length = 12 Mb) and accuracy, as evidenced by the exceptionally high completeness of the benchmarked set of conserved single-copy orthologous genes (BUSCO completeness = 99.1%). These quality metrics place our assembly ahead of the published Coleopteran genomes, including that of an insect model, the red flour beetle (Tribolium castaneum). The structural annotation of the nuclear genome assembly contained a highly-accurate set of 16,371 protein-coding genes, with only 2.8% missing BUSCOs, and the expected number of non-coding RNAs. The number and structure of paralogous genes in a gene family like Sigma GST is lower than in another scarab beetle (Onthophagus taurus), but higher than in the red flour beetle (Tribolium castaneum), which suggests expansion of this GST class in Scarabaeidae. The quality of our gene models was also confirmed with the correct placement of O. rhinoceros among other members of the rhinoceros beetles (subfamily Dynastinae) in a phylogeny based on the sequences of 95 protein-coding genes in 373 beetle species from all major lineages of Coleoptera. Finally, we provide a list of 30 candidate dsRNA targets whose orthologs have been experimentally validated as highly effective targets for RNAi-based control of several beetles.

Conclusions

The genomic resources produced in this study form a foundation for further functional genetic research and management programs that may inform the control and surveillance of O. rhinoceros populations, and we demonstrate the efficacy of de novo genome assembly using long-read ONT data from a single field-caught insect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08628-z.

Enhanced Zika virus susceptibility of globally invasive Aedes aegypti populations

The drivers and patterns of zoonotic virus emergence in the human population are poorly understood. The mosquito Aedes aegypti is a major arbovirus vector native to Africa that invaded most of the world's tropical belt over the past four centuries, after the evolution of a "domestic" form that specialized in biting humans and breeding in water storage containers. Here, we show that human specialization and subsequent spread of A. aegypti out of Africa were accompanied by an increase in its intrinsic ability to acquire and transmit the emerging human pathogen Zika virus. Thus, the recent evolution and global expansion of A. aegypti promoted arbovirus emergence not solely through increased vector-host contact but also as a result of enhanced vector susceptibility.

The complete mitochondrial genome sequence of Oryctes rhinoceros (Coleoptera: Scarabaeidae) based on long-read nanopore sequencing

BACKGROUND

The coconut rhinoceros beetle (CRB, Oryctes rhinoceros) is a severe and invasive pest of coconut and other palms throughout Asia and the Pacific. The biocontrol agent, Oryctes rhinoceros nudivirus (OrNV), has successfully suppressed O. rhinoceros populations for decades but new CRB invasions started appearing after 2007. A single-SNP variant within the mitochondrial cox1 gene is used to distinguish the recently-invading CRB-G lineage from other haplotypes, but the lack of mitogenome sequence for this species hinders further development of a molecular toolset for biosecurity and management programmes against CRB. Here we report the complete circular sequence and annotation for CRB mitogenome, generated to support such efforts.

METHODS

Sequencing data were generated using long-read Nanopore technology from genomic DNA isolated from a CRB-G female. The mitogenome was assembled with Flye v.2.5, using the short-read Illumina sequences to remove homopolymers with Pilon, and annotated with MITOS. Independently-generated transcriptome data were used to assess the O. rhinoceros mitogenome annotation and transcription. The aligned sequences of 13 protein-coding genes (PCGs) (with degenerate third codon position) from O. rhinoceros, 13 other Scarabaeidae taxa and two outgroup taxa were used for the phylogenetic reconstruction with the Maximum likelihood (ML) approach in IQ-TREE and Bayesian (BI) approach in MrBayes.

RESULTS

The complete circular mitogenome of O. rhinoceros is 20,898 bp in length, with a gene content canonical for insects (13 PCGs, two rRNA genes, and 22 tRNA genes), as well as one structural variation (rearrangement of trnQ and trnI) and a long control region (6,204 bp). Transcription was detected across all 37 genes, and interestingly, within three domains in the control region. ML and BI phylogenies had the same topology, correctly grouping O. rhinoceros with one other Dynastinae taxon, and recovering the previously reported relationship among lineages in the Scarabaeidae. In silico PCR-RFLP analysis recovered the correct fragment set that is diagnostic for the CRB-G haplogroup. These results validate the high-quality of the O. rhinoceros mitogenome sequence and annotation.

Using spatial genetics to quantify mosquito dispersal for control programs

Background

Hundreds of millions of people get a mosquito-borne disease every year and nearly one million die. Transmission of these infections is primarily tackled through the control of mosquito vectors. The accurate quantification of mosquito dispersal is critical for the design and optimization of vector control programs, yet the measurement of dispersal using traditional mark-release-recapture (MRR) methods is logistically challenging and often unrepresentative of an insect’s true behavior. Using Aedes aegypti (a major arboviral vector) as a model and two study sites in Singapore, we show how mosquito dispersal can be characterized by the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors.

Results

Using simple oviposition traps, we captured adult female Ae. aegypti across high-rise apartment blocks and genotyped them using genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance which results from one generation of successful breeding (effective dispersal), using the distance separating full siblings and 2nd- and 3rd-degree relatives (close kin). The estimated dispersal distance kernel was exponential (Laplacian), with a mean dispersal distance (and dispersal kernel spread σ) of 45.2 m (95% CI 39.7–51.3 m), and 10% probability of a dispersal > 100 m (95% CI 92–117 m). Our genetically derived estimates matched the parametrized dispersal kernels from previous MRR experiments. If few close kin are captured, a conventional genetic isolation-by-distance analysis can be used, as it can produce σ estimates congruent with the close-kin method if effective population density is accurately estimated. Genetic patch size, estimated by spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel “tail” that influences, for example, the critical radii of release zones and the speed of Wolbachia spread in mosquito replacement programs.

Conclusions

We demonstrate that spatial genetics can provide a robust characterization of mosquito dispersal. With the decreasing cost of next-generation sequencing, the production of spatial genetic data is increasingly accessible. Given the challenges of conventional MRR methods, and the importance of quantified dispersal in operational vector control decisions, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.

Complete genome sequence of Oryctes rhinoceros nudivirus isolated from the coconut rhinoceros beetle in Solomon Islands

Oryctes rhinoceros nudivirus (OrNV) has been an effective biocontrol agent against the insect pest Oryctes rhinoceros (Coleoptera: Scarabaeidae) for decades, but there is evidence that resistance could be evolving in some host populations. We detected OrNV infection in O. rhinoceros from Solomon Islands and used Oxford Nanopore Technologies (ONT) long-read sequencing to determine the full length of the virus genomic sequence isolated from an individual belonging to a mitochondrial lineage (CRB-G) that was previously reported as resistant to OrNV. The complete circular genome of the virus consisted of 125,917 nucleotides, 1.698 bp shorter than the originally-described full genome sequence of Ma07 strain from Malaysia. We found 130 out of 139 previously annotated ORFs (seven contained interrupted/non-coding sequences, two were identified as duplicated versions of the existing genes), as well as a putatively inverted regions containing four genes. These results demonstrate the usefulness of a long-read sequencing technology for resolving potential structural variations when describing new virus isolates. While the Solomon Islands isolate exhibited 99.41 % nucleotide sequence identity with the originally described strain, we found several genes, including a core gene (vlf-1), that contained multiple amino acid insertions and/or deletions as putative polymorphisms of large effect. Our complete annotated genome sequence of a newly found isolate in Solomon Islands provides a valuable resource to help elucidate the mechanisms that compromise the efficacy of OrNV as a biocontrol agent against the coconut rhinoceros beetle.

Improved reference genome of Aedes aegypti informs arbovirus vector control

Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.

An improved, fully re-annotated Aedes aegypti genome assembly (AaegL5) provides insights into the sex-determining M locus, chemosensory systems that help mosquitoes to hunt humans and loci involved in insecticide resistance and will help to generate intervention strategies to fight this deadly disease vector.

Modelling of factors influencing the effect of osmotic solution on reduction of selected microorganisms

AIMS

The goal of this research is to model the effects of two osmotic solutions factors on the reduction of selected microorganisms, and to assess the application in osmotic dehydration process of animal raw materials from the aspect of microbiological safety.

METHODS AND RESULTS

Sugar beet molasses and aquatic osmotic solution were prepared and inoculated with Escherichia coli, Listeria monocytogenes and Salmonella spp. Varied factors of osmotic solutions were: time, temperature and concentration of osmotic solutions. Samples of osmotic solutions were subjected to standard and modified microbiological ISO methods. The result showed that increase in factors had a positive effect on the reduction of microbiological load, while the time of the process was the most influential technological parameter. Number of L. monocytogenes was reduced to <10 CFU per g at the end of the process in the highest concentration of sugar beet molasses at all process temperatures.

CONCLUSIONS

Developed mathematical models of reduction ratios for tested microorganisms were statistically significant, allowing good prediction of reduction ratio values based on applied factors.

SIGNIFICANCE AND IMPACT OF THE STUDY

Obtained levels of reduction of all tested microorganisms present good base for the production of safe osmotically dehydrated products of animal origin.

Mapping the virome in wild-caught Aedes aegypti from Cairns and Bangkok

Medically important arboviruses such as dengue, Zika, and chikungunya viruses are primarily transmitted by the globally distributed mosquito Aedes aegypti. Increasing evidence suggests that transmission can be influenced by mosquito viromes. Herein RNA-Seq was used to characterize RNA metaviromes of wild-caught Ae. aegypti from Bangkok (Thailand) and from Cairns (Australia). The two mosquito populations showed a high degree of similarity in their viromes. BLAST searches of assembled contigs suggest up to 27 insect-specific viruses may infect Ae. aegypti, with up to 23 of these currently uncharacterized and up to 16 infecting mosquitoes from both Cairns and Bangkok. Three characterized viruses dominated, Phasi Charoen-like virus, Humaita-Tubiacanga virus and Cell fusing agent virus, and comparisons with other available RNA-Seq datasets suggested infection levels with these viruses may vary in laboratory-reared mosquitoes. As expected, mosquitoes from Bangkok showed higher mitochondrial diversity and carried alleles associated with knock-down resistance to pyrethroids. Blood meal reads primarily mapped to human genes, with a small number also showing homology with rat/mouse and dog genes. These results highlight the wide spectrum of data that can be obtained from such RNA-Seq analyses, and suggests differing viromes may need to be considered in arbovirus vector competence studies.

The queenslandensis and the type Form of the Dengue Fever Mosquito (Aedes aegypti L.) Are Genomically Indistinguishable

BACKGROUND

The mosquito Aedes aegypti (L.) is a major vector of viral diseases like dengue fever, Zika and chikungunya. Aedes aegypti exhibits high morphological and behavioral variation, some of which is thought to be of epidemiological significance. Globally distributed domestic Ae. aegypti have often been grouped into (i) the very pale variety queenslandensis and (ii) the type form. Because the two color forms co-occur across most of their range, there is interest in understanding how freely they interbreed. This knowledge is particularly important for control strategies that rely on mating compatibilities between the release and target mosquitoes, such as Wolbachia releases and SIT. To address this question, we analyzed nuclear and mitochondrial genome-wide variation in the co-occurring pale and type Ae. aegypti from northern Queensland (Australia) and Singapore.

METHODS/FINDINGS

We typed 74 individuals at a 1170 bp-long mitochondrial sequence and at 16,569 nuclear SNPs using a customized double-digest RAD sequencing. 11/29 genotyped individuals from Singapore and 11/45 from Queensland were identified as var. queenslandensis based on the diagnostic scaling patterns. We found 24 different mitochondrial haplotypes, seven of which were shared between the two forms. Multivariate genetic clustering based on nuclear SNPs corresponded to individuals' geographic location, not their color. Several family groups consisted of both forms and three queenslandensis individuals were Wolbachia infected, indicating previous breeding with the type form which has been used to introduce Wolbachia into Ae. aegypti populations.

CONCLUSION

Aedes aegypti queenslandensis are genomically indistinguishable from the type form, which points to these forms freely interbreeding at least in Australia and Singapore. Based on our findings, it is unlikely that the presence of very pale Ae. aegypti will affect the success of Aedes control programs based on Wolbachia-infected, sterile or RIDL mosquitoes.

Aedes aegypti has spatially structured and seasonally stable populations in Yogyakarta, Indonesia

BACKGROUND

Dengue fever, the most prevalent global arboviral disease, represents an important public health problem in Indonesia. Control of dengue relies on the control of its main vector, the mosquito Aedes aegypti, yet nothing is known about the population history and genetic structure of this insect in Indonesia. Our aim was to assess the spatio-temporal population genetic structure of Ae. aegypti in Yogyakarta, a densely populated region on Java with common dengue outbreaks.

METHODS

We used multiple marker systems (microsatellites, nuclear and mitochondrial genome-wide single nucleotide polymorphisms generated via Restriction-site Associated DNA sequencing) to analyze 979 Ae. aegypti individuals collected from the Yogyakarta city and the surrounding hamlets during the wet season in 2011 and the following dry season in 2012. We employed individual- and group-based approaches for inferring genetic structure.

RESULTS

We found that Ae. aegypti in Yogyakarta has spatially structured and seasonally stable populations. The spatial structuring was significant for the nuclear and mitochondrial markers, while the temporal structuring was non-significant. Nuclear markers identified three main genetic clusters, showing that hamlets have greater genetic isolation from each other and from the inner city sites. However, one hamlet experienced unrestricted mosquito interbreeding with the inner city, forming a single genetic cluster. Genetic distance was poorly correlated with the spatial distance among mosquito samples, suggesting stronger influence of human-assisted gene flow than active mosquito movement on spatial genetic structure. A star-shaped mitochondrial haplotype network and a significant R(2) test statistic (R(2) = 0.0187, P = 0.001) support the hypothesis that Ae. aegypti in Yogyakarta originated from a small or homogeneous source and has undergone a relatively recent demographic expansion.

CONCLUSION

We report the first insights into the spatio-temporal genetic structure and the underlying processes in the dengue fever mosquito from Yogyakarta, Indonesia. Our results provide valuable information on the effectiveness of local control measures as well as guidelines for the implementation of novel biocontrol strategies such as release of Wolbachia-infected mosquitoes.

Contrasting genetic structure between mitochondrial and nuclear markers in the dengue fever mosquito from Rio de Janeiro: implications for vector control

Dengue is the most prevalent global arboviral disease that affects over 300 million people every year. Brazil has the highest number of dengue cases in the world, with the most severe epidemics in the city of Rio de Janeiro (Rio). The effective control of dengue is critically dependent on the knowledge of population genetic structuring in the primary dengue vector, the mosquito Aedes aegypti. We analyzed mitochondrial and nuclear genomewide single nucleotide polymorphism markers generated via Restriction-site Associated DNA sequencing, as well as traditional microsatellite markers in Ae. aegypti from Rio. We found four divergent mitochondrial lineages and a strong spatial structuring of mitochondrial variation, in contrast to the overall nuclear homogeneity across Rio. Despite a low overall differentiation in the nuclear genome, we detected strong spatial structure for variation in over 20 genes that have a significantly altered expression in response to insecticides, xenobiotics, and pathogens, including the novel biocontrol agent Wolbachia. Our results indicate that high genetic diversity, spatially unconstrained admixing likely mediated by male dispersal, along with locally heterogeneous genetic variation that could affect insecticide resistance and mosquito vectorial capacity, set limits to the effectiveness of measures to control dengue fever in Rio.

Genome-wide SNPs lead to strong signals of geographic structure and relatedness patterns in the major arbovirus vector, Aedes aegypti

Background

Genetic markers are widely used to understand the biology and population dynamics of disease vectors, but often markers are limited in the resolution they provide. In particular, the delineation of population structure, fine scale movement and patterns of relatedness are often obscured unless numerous markers are available. To address this issue in the major arbovirus vector, the yellow fever mosquito (Aedes aegypti), we used double digest Restriction-site Associated DNA (ddRAD) sequencing for the discovery of genome-wide single nucleotide polymorphisms (SNPs). We aimed to characterize the new SNP set and to test the resolution against previously described microsatellite markers in detecting broad and fine-scale genetic patterns in Ae. aegypti.

Results

We developed bioinformatics tools that support the customization of restriction enzyme-based protocols for SNP discovery. We showed that our approach for RAD library construction achieves unbiased genome representation that reflects true evolutionary processes. In Ae. aegypti samples from three continents we identified more than 18,000 putative SNPs. They were widely distributed across the three Ae. aegypti chromosomes, with 47.9% found in intergenic regions and 17.8% in exons of over 2,300 genes. Pattern of their imputed effects in ORFs and UTRs were consistent with those found in a recent transcriptome study. We demonstrated that individual mosquitoes from Indonesia, Australia, Vietnam and Brazil can be assigned with a very high degree of confidence to their region of origin using a large SNP panel. We also showed that familial relatedness of samples from a 0.4 km² area could be confidently established with a subset of SNPs.

Conclusions

Using a cost-effective customized RAD sequencing approach supported by our bioinformatics tools, we characterized over 18,000 SNPs in field samples of the dengue fever mosquito Ae. aegypti. The variants were annotated and positioned onto the three Ae. aegypti chromosomes. The new SNP set provided much greater resolution in detecting population structure and estimating fine-scale relatedness than a set of polymorphic microsatellites. RAD-based markers demonstrate great potential to advance our understanding of mosquito population processes, critical for implementing new control measures against this major disease vector.

[Serum haptoglobin and alpha-1 antitrysin levels as biological evolution markers in patients with gastric and colorectal cancer]

Increased serum levels of acute-phase proteins in cancers are considered to be indicative for the presence of a tumour. Following radical treatment, their serum levels are expected to revert to normal. Haptoglobin and alpha-1 antitrypsin have important serum concentrations which allow precision in the detection of their variations. The aim of the study was to determine wherther serial measurements of haptoglobin and alpha-1-antitrypsin levels could be relevant in postoperative monitoring of patients with gastrointestinal cancer. As a model advanced disease was used. Haptoglobin and alpha-1-antitypsin serum levels were determined in 20 healthy controls, andin 100 camples of sera originating from 61 patients with advanced disease: 21 with 16 gastric carcinoma, 27 with 17 large bowel cancer, and 52 with 28 rectal cancer. Both proteins were determined by radial immunodiffusion M+/-SD in healthy controls, being 2.167 +/- 0.733 g/l for HP and 2.372 +/- 0.481 g/l for alpha-1-antitrypsin. Haptoglobin M+/-SD was 2.256 +/- 1.466 in gastric carcinoma, 3.031 +/- 1.517 in bowel cancer and 2.964 +/- 1.189 in rectal cancer. The difference from healthy controls was significant in bowel cancer (p < 0.05) and rectal cancer (p < 0.01). It was also significant between gastric carcinoma and rectal cancer (p < 0.05). Alpha-1-antitrypsin M+/-SD was 2.557 +/- 1.063 in gastric carcinoma, 2.885 +/- 1.746 in bowel cancer and 3.111 +/- 1.192 in rectal cancer. The difference from healthy subjects was significant only for rectal cancer (p < 0.01). In 28 patients with serial sera samples, the disease progression was associated in 64-68% of them with further increase of haptoglobin and alpha-1-antitrypsin levels. Development of microangiopathic haemolytic anaemia decreased levels of both haptoglobin (1.444 +/- 1.165 vs 2.833 +/- 1.311 in the whole group, (p < 0.05) and alpha-1-antitrypsin (1.405 +/- 0.859 vs. 2.934 +/- 1.252 in the whole group, (p < 0.01). Serial determination of haptoglobin and alpha-1-antitrypsin levels seem to be useful in postoperative monitoring of patients with rectal cancer and possibly bowel cancer. They are of no relevance in monitoring patients with gastric carcinoma. Microangiopathic haemolytic anaemia development is associated with serum depletion of both haptoglobin and alpha-1-antitrypsin.

Potentiometric determination of stability constants of cyanoacetato complexes of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and lead(II)

Stability constants of cyanoacetato complexes of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and lead(II) were determined potentiometrically at 25.0 +/- 0.1 degrees and ionic strength 2M (sodium perchlorate). The stability constants were evaluated by a weighted least-squares method.