Aint/Tacc3 is highly expressed in proliferating mouse tissues during development, spermatogenesis, and oogenesis.

Aint was originally identified on the basis of its interaction in vitro with the aryl hydrocarbon nuclear receptor translocator (Arnt). Arnt is a common heterodimerization partner in the basic helix-loop-helix (bHLH)-PER-ARNT-SIM (PAS) protein family and is involved in diverse biological functions. These include xenobiotic metabolism, hypoxic response, and circadian rhythm. In addition, Arnt has a crucial role during development. Aint is a member of a growing family of transforming acidic coiled-coil (TACC) proteins and is the murine homologue of human TACC3. Here we report the spatiotemporal expression of Tacc3 mRNA and protein in embryonic, postnatally developing, and adult mouse tissues using in situ hybridization and immunocytochemistry. Tacc3 mRNA was highly expressed in proliferating cells of several organs during murine development. However, the only adult tissues expressing high levels were testis and ovary. Immunocytochemistry revealed that Tacc3 is a nuclear protein. Our results suggest that Tacc3 has an important role in murine development, spermatogenesis, and oogenesis.     

Processing of McCoy cell cultures infected with Chlamydia trachomatis: sequential isolation of chlamydial elementary bodies and lipopolysaccharide

Abstract Triton X-100 (TX100) enhances the liberation of chlamydial elementary bodies (EB) from host cells and dissolves the host cell membrane. In the presence of TX100 only differential centrifugation is needed to isolate reasonably pure EBs. The remaining high-speed supernatant still contains a large part of the chlamydial lipopolysaccharide (LPS), which can be isolated with the standard phenol-chloroform-petroleum ether extraction.     

Practical identifiability of growth and substrate consumption models

The estimation of parameters in several dynamic models, which describe growth and substrate consumption, has been carried out using a modified Gauss-Newton-type method. The four models considered are Monod, Contois, linear specific growth rate, and an enzyme kinetic model. The initial values of the differential equations are included in the parameter vector which will be estimated. The efficiency of the method and the confidence limits of the parameters were studied using simulated measurement noise. The experimental results describe Trichoderma viride growing on glucose as the main carbon source.     

Correlations between hyaluronan and epidermal proliferation as studied by [H]glucosamine and [H]thymidine incorporations and staining of hyaluronan on mitotic keratinocytes

The rates of keratinocyte proliferation and synthesis of Hyaluronan (HA) were studied in human whole-skin organ culture by labeling with [6-³H]glucosamine and [³H]thymidine, respectively, to reveal possible correlations between the two functions of the cell. HA distribution in epidermis was examined by staining with a specific probe prepared front cartilage proteoglycan. The keratinocyte proliferation rate was low on the first 2 culture days, but showed a tenfold increase on the third and fourth days while the synthesis of HA proceeded at a relatively stable level throughout the same period. The most intensive staining of HA occurred in the uppermost spinous cell layer, whereas mitotic cells resided in the basal and suprabasal layers. The keratinocytes under various stages of mitosis were surrounded by a HA staining not more intense than that around nondividing basal cells, but a thick pad of HA appeared rapidly between the daughter cells. These findings suggest that newly synthesized HA is associated with the separation of keratinocytes following mitosis but the majority of the synthesis and content of HA in epidermis is involved in other keratinocyte activities such as maintenance of the extracellular space and cell-cell interactions during migration and differentiation.     

Calbindin D-28k-immunoreactivity in rat muscle spindles during postnatal maturation and after denervation

Summary Calbindin D-28k-immunoreactivity has been demonstrated in some of the intrafusal muscle fibres and in the capsule of adult rat muscle spindles. In this study, the immunocytochemical localization of calbindin D-28k in the muscle spindles of triceps surae muscle was studied during postnatal maturation and after denervation. In young rats calbindin D-28k-immunoreactivity was seen in a few intrafusal fibres, first at the age of 4 days. At the 7th day, three calbindin D-28k-immunoreactive fibres and one unlabelled fibre were seen in most muscle spindles, as in adult rats. The spindle capsule and perineurial sheath of nerves were first seen to exhibit calbindin D-28k immunoreactivity at the age of 14 days, and thereafter the localization of calbinding D-28k-like immunoreactivity was similar to that in adult rats. After denervation, calbindin D-28k-immunoreactivity remained in intrafusal muscle fibres and the spindle capsule for a long period. After two months of denervation, calbindin D-28k immunoreactivity could still be seen in the spindle capsule, but the intrafusal fibres were not labelled.The innervation is known to have trophic effects on the intrafusal fibres. The present findings suggest that the expression of calbindin D-28k-immunoreactivity in maturating muscle spindles may be induced by the developing innervation. The decrease of calbindin D-28k-immunoreactivity in intrafusal fibres after denervation may be due to the loss of trophic factors released by the nerves.     

Bacteriophage-resistant mutants of Salmonella typhimurium deficient in two major outer membrane proteins.

Mutants resistant to bacteriophages (P221 and PH105 or PH51) were isolated from a rfa strain of Salmonella typhimurium. They were found deficient in separate 33,000- to 36,000-dalton band proteins (major band proteins). Double mutants derived from both types of mutants were deficient in both of the bands. The growth behavior of all the mutants was normal. The outer membrane of the mutants appeared to be more wrinkled than normal and formed vesicles in many of the mutants. In freeze-fractured cells, changes were seen in the outer membrane (particleless patches in the concave fracture face, the particles themselves being smaller than normal). These changes were more marked in the double mutants.     

Hyaluronan in breast cancer: correlations with nitric oxide synthases and tyrosine nitrosylation.

Reactive oxygen species (ROS), including nitric oxide (NO(*)), are associated with all steps of carcinogenesis. Hyaluronan (HA), a high-molecular-mass glycosaminoglycan overexpressed in a variety of human malignancies also has ROS-scavenging properties. We histochemically studied the level of HA in breast carcinoma cells and their stroma and compared it with the expression of NO(*) synthases (NOSs), major antioxidant enzymes, and nitrotyrosine. We also assessed whether the level of HA correlates with traditional prognostic factors of breast cancer and survival. Stromal HA level was moderate or high in all the samples studied (n=185), and 84% of the lesions showed HA-positive carcinoma cells. Intense stromal HA signal was associated with high neuronal NOS expression (p=0.009), whereas tumor-cell associated HA was inversely correlated with nitrotyrosine expression (p=0.027). Of the traditional prognostic factors, tumor cell-associated HA was correlated with poor differentiation (p=0.011), and high stromal HA levels were associated with aggressive features of the carcinomas such as large primary tumor (p=0.002), poor differentiation (p=0.019), and estrogen (p=0.012) and progesterone receptor negativity (p=0.009). High stromal HA level also significantly predicted poorer survival. The strong positive correlation between neuronal NOS and stromal HA could reflect NO(*)-stimulated synthesis of HA, an extracellular matrix alteration that favors breast cancer progression. Furthermore, it is suggested that, while acting as a scavenger of NO(*)-derived radicals, cell-associated HA undergoes partial fragmentation, release from receptors, and further degradation in lysosomes, and thus becomes undetectable in histological sections.