A sixth-level habitat cascade increases biodiversity in an intertidal estuary.

Many studies have documented habitat cascades where two co-occurring habitat-forming species control biodiversity. However, more than two habitat-formers could theoretically co-occur. We here documented a sixth-level habitat cascade from the Avon-Heathcote Estuary, New Zealand, by correlating counts of attached inhabitants to the size and accumulated biomass of their biogenic hosts. These data revealed predictable sequences of habitat-formation (=attachment space). First, the bivalve Austrovenus provided habitat for green seaweeds (Ulva) that provided habitat for trochid snails in a typical estuarine habitat cascade. However, the trochids also provided habitat for the nonnative bryozoan Conopeum that provided habitat for the red seaweed Gigartina that provided habitat for more trochids, thereby resetting the sequence of the habitat cascade, theoretically in perpetuity. Austrovenus is here the basal habitat-former that controls this "long" cascade. The strength of facilitation increased with seaweed frond size, accumulated seaweed biomass, accumulated shell biomass but less with shell size. We also found that Ulva attached to all habitat-formers, trochids attached to Ulva and Gigartina, and Conopeum and Gigartina predominately attached to trochids. These "affinities" for different habitat-forming species probably reflect species-specific traits of juveniles and adults. Finally, manipulative experiments confirmed that the amount of seaweed and trochids was important and consistent regulators of the habitat cascade in different estuarine environments. We also interpreted this cascade as a habitat-formation network that describes the likelihood of an inhabitant being found attached to a specific habitat-former. We conclude that the strength of the cascade increased with the amount of higher-order habitat-formers, with differences in form and function between higher and lower-order habitat-formers, and with the affinity of inhabitants for higher-order habitat-formers. We suggest that long habitat cascades are common where species traits allow for physical attachment to other species, such as in marine benthic systems and old forest.

Genome of non-living cells: trash or recycle?

Reproductive technologies have been often used as a tool in research not strictly connected with developmental biology. In this study, we retrace the experimental routes that have led to the adoption of two reproductive technologies, ICSI and somatic cell nuclear transfer (SCNT), as biological assays to probe the 'functionality' of the genome from dead cells. The structural peculiarities of the spermatozoa nucleus, namely its lower water content and its compact chromatin structure, have made it the preferred cell for these experiments. The studies, primarily focused on mice, have demonstrated an unexpected stability of the spermatozoa nuclei, which retained the capacity to form pronuclei once injected into the oocytes even after severe denaturing agents like acid treatment and high-temperature exposure. These findings inspired further research culminating in the production of mice after ICSI of lyophilized spermatozoa. The demonstrated non-equivalence between cell vitality and nuclear vitality in spermatozoa prompted analogous studies on somatic cells. Somatic cells were treated with the same physical stress applied to spermatozoa and were injected into enucleated sheep oocytes. Despite the presumptive fragile nuclear structure, nuclei from non-viable cells (heat treated) directed early and post-implantation embryonic development on nuclear transfer, resulting in normal offspring. Recently, lyophilized somatic cells used for nuclear transfer have developed into normal embryos. In summary, ICSI and SCNT have been useful tools to prove that alternative strategies for storing banks of non-viable cells are realistic. Finally, the potential application of freeze-dried spermatozoa and cells is also discussed.

Significance of lipopolysaccharide-binding protein (an acute phase protein) in monitoring critically ill patients.

INTRODUCTION: The present study was conducted to assess the value of serum concentration of lipopolysaccharide-binding protein (LBP) in patients with systemic inflammatory response syndrome (SIRS), sepsis and septic shock with respect to its ability to differentiate between infectious and noninfectious etiologies in SIRS and to predict prognosis. METHODS: This prospective cohort study was conducted in a multidisciplinary intensive care unit. Sixty-eight patients, admitted consecutively to the intensive care unit and who met criteria for SIRS, sepsis or septic shock were included. Serum LBP was measured using an immunochemiluminiscence assay. RESULTS: Serum levels of LBP were significantly increased in patients with SIRS (n = 40; median 30.6 microg/ml, range 9.2-79.5 microg/ml), sepsis (n = 19; median 37.1 microg/ml, range 11.8-76.2 microg/ml) and septic shock (n = 9; median 59.7 microg/ml, range 31.1-105 microg/ml), as compared with levels in the healthy volunteers (5.1 +/- 2.2 microg/ml; P < 0.0001). Serum LBP at study entry was statistically significantly lower in patients with SIRS than in those with septic shock (P < 0.014); no statistically significant difference existed between patients with SIRS and those with sepsis (P = 0.61). Specificity and sensitivity of an LBP concentration of 29.8 microg/ml to distinguish between infectious and noninfectious etiologies for SIRS were 50% and 74.2%, respectively. There was no statistically significant difference in LBP concentration between survivors and nonsurvivors in both groups of patients. Furthermore, in septic patients the LBP response appeared to exhibit a decreased magnitude. CONCLUSION: LBP is a nonspecific marker of the acute phase response and cannot be used as a diagnostic tool for differentiating between infectious and noninfectious etiologies of SIRS.

CSF and serum orosomucoid (alpha-1-acid glycoprotein) in patients with multiple sclerosis: a comparison among particular subgroups of MS patients.

INTRODUCTION: To compare cerebrospinal fluid (CSF) and serum orosomucoid (alpha-1-acid glycoprotein-AAG) concentrations in various subgroups of patients with multiple sclerosis (MS). MATERIALS AND METHODS: CSF and serum AAG concentrations, AAG quotient (i.e., CSF AAG/serum AAGx10(3)) and index were determined in a group of 59 patients with clinically definite or probable MS. Patients were subdivided according to the disease form, disease severity according to an expanded disability status scale (EDSS), its treatment, disease duration and sex. RESULTS: CSF AAG was increased in 52.5% of the patients and AAG quotient even in 64.4%. An increase in the CSF AAG concentration, as well as in AAG quotient and index, appear only after several years of disease duration, while no significant correlation with age has been found. This suggests that CSF AAG changes in MS represent a secondary, unspecific phenomenon and that this protein is not relevant for the aethiopathogenesis of the disease. Nevertheless, the finding of subnormal CSF AAG levels in some MS patients in remission (never observed in those in the attack) implies the possibility that CSF AAG may be used as a "state marker" in MS. Serum AAG levels were significantly lower in secondary progressive form and in severely disabled patients. This observation suggest that serum AAG values determination might have some prognostic significance. Further studies are, however, needed. Serum AAG should be investigated in parallel with other CSF and serum protein fractions in order to establish a pannel of examinations enabling multiple statistical analyses. This approach may lead to the finding of a "complex state marker" enabling thus to evaluate more precisely disease course in individual patients and to accept appropriate therapeutic measures.