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Cupiennius salei single insulin-like growth factor-binding domain protein (SIBD-1), which exhibits an IGFBP N-terminal domain-like profile, was identified in the hemocytes of the spider C. salei. SIBD-1 was purified by RP-HPLC and the sequence determined by a combination of Edman degradation and 5'-3'- RACE PCR. The peptide (8676.08 Da) is composed of 78 amino acids, contains six intrachain disulphide bridges and carries a modified Thr residue at position 2. SIBD-1 mRNA expression was detected by quantitative real-time PCR mainly in hemocytes, but also in the subesophageal nerve mass and muscle. After infection, the SIBD-1 content in the hemocytes decreases and, simultaneously, the temporal SIBD-1 expression seems to be down-regulated. Two further peptides, SIBD-2 and IGFBP-rP1, also exhibiting IGFBP N-terminal domain variants with unknown functions, were identified on cDNA level in spider hemocytes and venom glands. We conclude that SIBD-1 may play an important role in the immune system of spiders.

Background & Aims Late-onset symptoms of urea-cycle disorder may lead to a life-threatening disease which is often undetected. We report the clinical and metabolic manifestations of acute hyperammonemic encephalopathy in a 47-year-old asymptomatic man with ornithine transcarbamylase (OTC) deficiency. The hyperammonemic encephalopathy was unmasked by a high-protein Atkins diet. Methods Genetic analysis of the patient's family, 89 unrelated Ashkenazi Jewish and 50 unrelated Europeans subjects was performed using polymerase chain reaction amplification and DNA sequencing of the OTC gene. Results Treatment with hemodialysis, provision of adequate calories to prevent catabolism, and protein elimination for 24h followed by protein restriction and ammonia scavenging medications effectively lowered the patient's plasma ammonia level and resulted in full recovery. Genetic analysis of the OTC gene revealed a novel hemizygous missense mutation in exon 5 (c.477T>G), leading to an isoleucine-to-methionine substitution in codon 159 (Ile159Met). Further genetic analysis of the patient's family yielded the mutation in many of them, although findings were negative in 89 unrelated Ashkenazi Jewish and 50 unrelated Europeans subjects. Conclusions This is the first reported case of an adult urea-cycle defect unmasked by the Atkins diet. Measurements of serum ammonia level must be part of the basic work-up in all patients presenting with encephalopathy of unknown origin even in the absence of liver dysfunction. Awareness of this important association can contribute to prompt diagnosis and life-saving treatment. Correct diagnosis is also important to prevent future recurrences and to provide genetic counselling for family members.