The substitution of arginine for glycine 85 of the alpha 1(I) procollagen chain results in mild osteogenesis imperfecta. The mutation provides direct evidence for three discrete domains of cooperative melting of intact type I collagen.

We report a case of mild osteogenesis imperfecta in a 56-year-old male undergoing aortic valve replacement surgery. The primary defect in this patient was the substitution of arginine for glycine 85 in one of the two chains of alpha 1(I) procollagen. The thermal stability of the type I collagen synthesized by the patient's cultured skin fibroblasts was examined by enzymatic digestion. Digestion of the mutant type I collagen with trypsin and chymotrypsin at increasing temperatures sequentially generated three discrete collagenous fragments, approximately 90, 170, and 230 amino acids shorter than normal type I collagen. This incremental thermal denaturation is indicative of cooperative melting blocks within the type I collagen. This is the first demonstration of such cooperative blocks of melting in intact, essentially normal post-translationally modified type I collagen. This direct evidence for cooperative melting domains of uncut type I collagen suggests that discrete blocks of amino acids function as core sites stabilizing the collagen helix. The location of mutations of the alpha chains of type I collagen relative to these discrete blocks of amino acids may influence the severity of the disease phenotype.     

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Comparative morphology of surface ultrastructure of diphyllobothriidean tapeworms (Cestoda: Diphyllobothriidea)

Microtriches on the scolices and adjacent strobila of seven species of diphyllobothriidean cestodes (Bothridium pithonis, Cephalochlamys namaquensis, Dibothriocephalus latus, Duthiersia expansa, D. fimbriata, Ligula intestinalis, and Schistocephalus solidus) from different hosts (frogs, snakes, lizards, birds, and mammals) and biogeographic areas were examined using scanning and transmission electron microscopy. The basic structure of the tegument of the seven species studied does not differ markedly from that found in other cestodes. The main characteristic is the presence of electron‐dense bodies and vesicles in the distal cytoplasm. However, this study has shown differences in the morphology of microtriches even among species of the same family. Two different types of microtriches were found, filitriches and spinitriches, with the latter represented by two forms. Our study reveals that capilliform filitriches are most commonly found in Diphyllobothriidea. They were observed mainly on the strobila and the scolices of all but one studied species; individuals of L. intestinalis bore only coniform spinitriches on their surface. The same type of microtriches was found on the cirrus in D. latus. Gladiate spinitriches covered the scolex in both species of Duthiersia, and gladiate spinitriches interspersed with capilliform filitriches were observed on the anterior part of the strobila in D. fimbriata and the posterior part of the scolex in B. pithonis. Individuals of C. namaquensis were covered only by small acicular filitriches. No obvious pattern in the type and distribution of microtriches was observed among species that belong to different families and parasitize distantly related definitive hosts.     

First report of a hatched,hand‐reared,and released African oystercatcher

The African oystercatcher Haematopus moquini is a near‐threatened wader that is endemic to southern Africa. In the past, the species suffered a drastic decrease in nesting success due to human disturbance. We present the case report of an African oystercatcher that was hatched, hand‐reared, and released in the Western Cape, South Africa. African oystercatchers are semi‐altricial birds that tend to be highly sensitive to stress; as a result, strategies to minimize stress and the employment of surrogate parents and pre‐release acclimatization are important to ensure post‐release survival of hand‐reared chicks. Considering the lack of literature on the incubation and hand‐rearing of oystercatchers, this case report provides a basis for the development of hand‐rearing techniques that might be useful for the protection of this and other threatened wader species.     

Constant morphological patterns in the hemolymph vascular system of crayfish (Crustacea,Decapoda)

We present a study of the hemolymph vascular system of the marbled crayfish, Procambarus fallax f. virginalis, the only crayfish species known to be parthenogenetic. To identify potential evolutionary patterns, we compared data from a total of 48 specimens of P. fallax with 22 specimens of Orconectes limosus. Visualizations (2D and 3D) were carried out using a combination of classical and modern morphological techniques. Our data were compared to the existing literature.Like all Decapoda, both P. fallax and O. limosus have a hemolymph vascular system, consisting of a globular heart with seven off-branching arteries. We were able to visualize in detail the heart of crayfish for the first time, i.e., the myocard with its clusters of muscles running through the lumen of the heart, the valves and flaps of ostia and arteries. Furthermore, the branching patterns of the seven artery systems were analyzed. Anatomical structures identified to be consistent in all specimens of both species were combined as ground pattern of hemolymph vascular system features for Astacida.     

Microbiome Influences Prenatal and Adult Microglia in a Sex-Specific Manner

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