Changes in polysome profiles accompany trypanosome development

Development of the protozoan pathogen Trypanosoma brucei involves regulated changes in parasite structure, biochemistry, and the cell cycle. The transition of slender blood forms into stumpy bloodforms includes cell cycle arrest and a decrease in protein synthesis. The next stage in the development cycle, the procyclic form, shows increased protein synthesis and proliferates. To address the mechanism of the cyclical changes in protein synthesis, we examined two parameters: polyadenylation of mRNA and ribosome loading. We developed a method for analytical polyribosome analysis in T. brucei which provided excellent results with regard to reproducibility, yield of mRNA densely loaded with ribosomes, and separation of mRNA associated with different numbers of polyribosomes. Use of this technique allowed us to determine that the polysome profiles of the different developmental stages are distinctly different, with higher ribosome loading in the proliferating stages. The lengths of the poly(A) tails on the total population of RNA from the different developmental stages showed no significant variation. These data indicate that changes in polysome loading of mRNAs accompany development, and that they do not reflect bulk changes in polyadenylation. We speculate that developmental changes in translation reflect reduced translational initiation.

Distinct domains of a nucleolar protein mediate protein kinase binding, interaction with nucleic acids and nucleolar localization

Nopp44/46 is a phosphoprotein of the protozoan parasite Trypanosoma brucei that is localized to the nucleolus. Based on the primary sequence, Nopp44/46 appears to be a protein composed of distinct domains. This communication describes the relationship of these domains to the known functional interactions of the molecule and suggests that the amino-terminal region defines a novel homology region that functions in nucleolar targeting. We have previously shown that Nopp44/46 is capable of interacting with nucleic acids and associating with a protein kinase. Using in vitro transcription and translation, we now demonstrate that the nucleic acid binding function maps to the carboxy-terminal domain of the molecule, a region rich in arginine-glycine-glycine motifs. Our experiments reveal that a central region containing a high proportion of acidic residues is required for association with the protein kinase. Analysis of transfectants expressing epitope-tagged Nopp44/46 deletion constructs showed that the amino-terminal 96 amino acids allowed nuclear and nucleolar accumulation of the protein. This region of the molecule shows homology to several recently described nucleolar proteins. Deletion of a 27-amino-acid region within this domain abrogated nucleolar, but not nuclear, localization. These studies show that Nopp44/46 is composed of distinct modules, each of which plays a different role in molecular interactions. We suggest that this protein could facilitate interactions between sets of nucleolar molecules.

Immune cells in a mouse airway model of obliterative bronchiolitis

Obliterative bronchiolitis (OB), a form of chronic lung rejection, affects 50% of all lung-transplant recipients and is a major cause of morbidity and mortality. We used the mouse tracheal allograft model of OB to quantitate inflammatory cells during disease progression to evaluate the pathogenesis of this disorder. Tracheas of BALB/c mice were implanted into C57BL/6, severe combined immunodeficiency (SCID), and BALB/c mice. Cyclosporin was administered at 25 mg/kg/d. Grafts were harvested at 2, 6, 10, and 15 wk, and analyzed immunohistochemically. Tracheal allografts developed epithelial injury and cellular infiltrates at 2 wk, epithelial denudation and complete luminal obliteration at 6 wk, and dense collagenous scarring by 15 wk. SCID allografts and isografts demonstrated intact epithelium throughout, although a mononuclear infiltrate was initially present at 2 wk in the SCID allografts. Immunohistochemical staining, using antibodies to mouse CD4(+) (T-helper lymphocyte), CD8(+) (T-cytotoxic/suppressor lymphocyte), and B lymphocytes, macrophages, and myofibroblasts, revealed large numbers of macrophages and CD4(+) and CD8(+) lymphocytes in allografts at 2 wk, compared with isografts. The allograft CD4(+)/CD8(+) ratio was 0.75 at 2 wk. Allografts demonstrated macrophage, myofibroblast, and CD4(+) predominance at 6 and 10 wk (CD4(+)/CD8(+) = 2/1), but by 15 wk had minimal cellularity and were densely scarred. SCID allografts demonstrated a macrophage-predominant infiltrate at 2 wk, with minimal cellularity at later time points. These results indicate that: (1) OB is predominantly an immunologic airway injury; and (2) CD4(+) and CD8(+) lymphocytes and macrophages play an important role in the evolution of airway inflammation and fibrosis. Additionally, this model suggests that chronic airway fibrosis follows a period of intense airway-directed, cell-mediated rejection.

Trypanosoma brucei: molecular cloning and stage-regulated expression of a malate dehydrogenase localized to the mitochondrion

African trypanosomes exhibit dramatic developmental changes in carbohydrate and energy metabolism, with cytochrome-mediated respiration playing an important role only in the insect stages. The parasites possess three isozymes of malate dehydrogenase, each of which has a different subcellular localization and, likely, a distinct metabolic role. We have cloned and characterized a cDNA encoding one of these malate dehydrogenases. Epitope tagging and transfection experiments demonstrate that the corresponding protein is localized to the mitochondrion and that an intact amino terminus is required for proper compartmentalization. The abundance of transcript is developmentally regulated, with higher levels in procyclic stage parasites.

Effect of pregnancy on the metabolic clearance rate and the volume of distribution of oxytocin in the baboon

Pharmacokinetic parameters of oxytocin (OT) metabolism were determined during the last third of pregnancy and again 4-8 wk after delivery in the baboon. Animals were placed on a tether system with venous and arterial access and a continuous monitoring of uterine contractions during gestation. Two methods of determining OT pharmacokinetics were utilized (bolus injection vs. continuous infusion). The metabolic clearance rate of OT as determined during the bolus trials (n = 7) was 22.2 +/- 1.5 ml.min-1.kg-1 in pregnancy and 16.3 +/- 1.4 ml.min-1.kg-1 postpartum (P < 0.05), respectively, and 23.7 +/- 2.8 vs. 16.9 +/- 3.7 ml.min-1.kg-1 (P < 0.05), respectively, as determined during the 1-h infusion trials (n = 4). The initial dilution volume and the volume of distribution at steady state of OT after administration did not differ between pregnant and postpartum animals (P > 0.05). The mean residence time (MRT) of OT was shorter during pregnancy, 7.7 +/- 0.8 vs. 10.8 +/- 1.2 min postpartum (P < 0.05). In summary, OT metabolism during pregnancy in the baboon is characterized by 1) increased clearance rate (1.4-fold), 2) accelerated turnover due to the shorter MRT, and 3) unaltered distribution.

The dilemma over the reuse of 'single-use' medical devices. A risk manager's perspective

Reusing "single-use" devices can provide cost savings, but must be handled with caution. A consensus among health care institutions concerning reuse has yet to be formed. Determining whether to reuse "single-use" devices requires research of the industry.

Functional identification of a Leishmania gene related to the peroxin 2 gene reveals common ancestry of glycosomes and peroxisomes

Glycosomes are membrane-bounded microbody organelles that compartmentalize glycolysis as well as other important metabolic processes in trypanosomatids. The compartmentalization of these enzymatic reactions is hypothesized to play a crucial role in parasite physiology. Although the metabolic role of glycosomes differs substantially from that of the peroxisomes that are found in other eukaryotes, similarities in signals targeting proteins to these organelles suggest that glycosomes and peroxisomes may have evolved from a common ancestor. To examine this hypothesis, as well as gain insights into the function of the glycosome, we used a positive genetic selection procedure to isolate the first Leishmania mutant (gim1-1 [glycosome import] mutant) with a defect in the import of glycosomal proteins. The mutant retains glycosomes but mislocalizes a subset glycosomal proteins to the cytoplasm. Unexpectedly, the gim1-1 mutant lacks lipid bodies, suggesting a heretofore unknown role of the glycosome. We used genetic approaches to identify a gene, GIM1, that is able to restore import and lipid bodies. A nonsense mutation was found in one allele of this gene in the mutant line. The predicted Gim1 protein is related the peroxin 2 family of integral membrane proteins, which are required for peroxisome biogenesis. The similarities in sequence and function provide strong support for the common origin model of glycosomes and peroxisomes. The novel phenotype of gim1-1 and distinctive role of Leishmania glycosomes suggest that future studies of this system will provide a new perspective on microbody biogenesis and function.

Daily changes in plasma and amniotic fluid prolactin during the last third of pregnancy in the baboon

Alterations in plasma and amniotic fluid prolactin (PRL) levels have not been previously described in the pregnant baboon. In addition, PRL increases dramatically in response to estrogens and thus might be a good marker for expression of estrogen's biologic action. Therefore, the purpose of this study was to characterize the changes in plasma and amniotic fluid PRL with advancing gestational age and assess whether there was a correlation between plasma estradiol and PRL levels. A tethered pregnant baboon model was utilized for these studies. Blood was collected from five animals every day at 0900-1000 h (AM value) and 1800 h (PM value) from 125 to 135 days of pregnancy until delivery. Amniotic fluid was collected every day in the morning. Samples were analyzed by RIA for PRL, estradiol, and progesterone. PRL did not change with advancing gestational age. However, PRL showed a significant diurnal variation, with the PM values significantly higher (p < 0.05) than the AM values. In contrast to findings for PRL, AM values for estradiol and progesterone were on average higher that PM values (p < 0.05). A significant correlation was observed between the log10 estradiol (AM+PM) and log10 PRL (AM) from the following day (r = 0.52; p < 0.05). Finally, amniotic fluid PRL was present in high concentrations (200-400 ng/ml) but did not vary with gestational age. In conclusion, PRL, estradiol, and progesterone show distinct diurnal variations during the last one-third of pregnancy in the baboon. In addition, plasma PRL is positively correlated with estradiol.

TCR engagement of CD4+CD8+ thymocytes in vitro induces early aspects of positive selection, but not apoptosis

Immature CD4/CD8 double-positive (DP) thymocytes expressing self MHC-restricted TCR are positively selected in response to TCR signals to survive and differentiate into functionally competent CD4 or CD8 single positive (SP) T cells. In contrast, DP precursors expressing autoreactive TCR are clonally deleted in response to TCR signals. We show here that in vitro TCR engagement of TCR(low) DP thymocytes rapidly triggers a variety of events considered to be hallmarks of positive selection in vivo. These include increased expression of CD5 and Bcl-2, termination of RAG-1 and pre-T(alpha) gene expression, and a switch in lck promoter usage. We also demonstrate that CD4- or CD28-mediated signals synergize with TCR signals to induce these outcomes. Finally, we show that the response of DP thymocytes to TCR engagement is selective in that clonal deletion, CD4/CD8 lineage commitment, and other events associated with maturation, such as changes in expression of Thy-1, HSA, MHC class I, and CD45-RB, were not induced. Thus, only subsets of maturational processes associated with positive selection in vivo were shown to be directly coupled to TCR signaling pathways at the DP stage. These observations support conclusions from in vivo systems suggesting that multiple, temporally separated TCR engagements are required to effect the entire spectrum of developmental changes associated with positive selection, and provide a conceptual and experimental framework for unraveling the complexity of positive selection.

Trypanosoma brucei: identification of an internal region of phosphoglycerate kinase required for targeting to glycosomal microbodies

Among the microbodies found in eukaryotes are the glycosomes of Trypanosoma brucei, thought to be closely related to peroxisomes. Two types of targeting signals for glycosomes have been identified thus far: type 1 at the C-terminus and type 2 at the N-terminus. In this report, we use an epitope-tagging system to characterize the targeting signal found on the minor glycosomal isozyme of phosphoglycerate kinase, 56PGK. No type 1 or 2 signal was found; rather, the topogenic information was found to be internal. Chimeric molecules formed with the cytoplasmic phosphoglycerate kinase isozyme indicate that a region between amino acids 24 and 91 of 56PGK is essential for glycosomal targeting. No homology was found between this region and peroxisomal proteins containing internal targeting signals.

TCR engagement of CD4+CD8+ thymocytes in vitro induces early aspects of positive selection, but not apoptosis

Immature CD4/CD8 double-positive (DP) thymocytes expressing self MHC-restricted TCR are positively selected in response to TCR signals to survive and differentiate into functionally competent CD4 or CD8 single positive (SP) T cells. In contrast, DP precursors expressing autoreactive TCR are clonally deleted in response to TCR signals. We show here that in vitro TCR engagement of TCR(low) DP thymocytes rapidly triggers a variety of events considered to be hallmarks of positive selection in vivo. These include increased expression of CD5 and Bcl-2, termination of RAG-1 and pre-T(alpha) gene expression, and a switch in lck promoter usage. We also demonstrate that CD4- or CD28-mediated signals synergize with TCR signals to induce these outcomes. Finally, we show that the response of DP thymocytes to TCR engagement is selective in that clonal deletion, CD4/CD8 lineage commitment, and other events associated with maturation, such as changes in expression of Thy-1, HSA, MHC class I, and CD45-RB, were not induced. Thus, only subsets of maturational processes associated with positive selection in vivo were shown to be directly coupled to TCR signaling pathways at the DP stage. These observations support conclusions from in vivo systems suggesting that multiple, temporally separated TCR engagements are required to effect the entire spectrum of developmental changes associated with positive selection, and provide a conceptual and experimental framework for unraveling the complexity of positive selection.

Mammalian mitogen-activated protein kinase pathways are regulated through formation of specific kinase-activator complexes

Mammalian cells contain at least three signaling systems which are structurally related to the mitogen-activated protein kinase (MAPK) pathway. Growth factors acting through Ras primarily stimulate the Raf/MEK/MAPK cascade of protein kinases. In contrast, many stress-related signals such as heat shock, inflammatory cytokines, and hyperosmolarity induce the MEKK/SEK(MKK4)/SAPK(JNK) and/or the MKK3 or MKK6/p38(hog) pathways. Physiological agonists of these pathway types are either qualitatively or quantitatively distinct, suggesting few common proximal signaling elements, although past studies performed in vitro, or in cells using transient over-expression, reveal interaction between the components of all three pathways. These studies suggest a high degree of cross-talk apparently not seen in vivo. We have examined the possible molecular basis of the differing agonist profiles of these three MAPK pathways. We report preferential association between MAP kinases and their activators in eukaryotic cells. Furthermore, using the yeast 2-hybrid system, we show that association between these components can occur independent of additional eukaryotic proteins. We show that SAPK(JNK) or p38(hog) activation is specifically impaired by co-expression of cognate dominant negative MAP kinase kinase mutants, demonstrating functional specificity at this level. Further divergence and insulation of the stress pathways occurs proximal to the MAPK kinases since activation of the MAPK kinase kinase MEKK results in SAPK(JNK) activation but does not cause p38(hog) phosphorylation. Therefore, in intact cells, the three MAPK pathways may be independently regulated and their components show specificity in their interaction with cognate cascade members. The degree of intermolecular specificity suggests that mammalian MAPK signaling pathways may remain distinct without the need for specific scaffolding proteins to sequester components of individual pathways.

Breast cancer patients' personality style, age, and treatment decision making

BACKGROUND

Previous studies have shown that whereas nearly all cancer patients want information, far fewer wish to make treatment decisions. Although breast cancer patients who were given a choice of lumpectomy versus mastectomy and were encouraged to make the decision were believed to do better psychologically, a 1994 study refuted this. Some authors suggest that patient personality style is an important consideration in decisional preference.

METHODS

Newly diagnosed breast cancer patients (n = 76) were surveyed within 6 months of surgery. They answered seven questions about patient and physician roles in the decision-making process. Additionally, they completed the Miller Behavioral Style Scale (MBSS), which categorizes "monitors," or information seekers, and "blunters," or information avoiders. Chi-square analyses were used to explore the relationship of personality style and age to treatment decision-making preferences.

RESULTS

Although 80% of women wanted a role in decision making, 74% wanted their surgeons to make a recommendation and when given, 94% followed the recommended treatment plan. Monitors and blunters were equally likely to want physician recommendations. Younger women, particularly those under age 40, were more likely to want a physician's recommendation. Of those women who had specific fears about their cancer (76%), only half of them revealed such fears to their doctors.

CONCLUSIONS

The notion that health care consumers, particularly younger ones, desire an independent choice of treatment was contradicted in this study. Physicians are encouraged to provide information and to probe regarding the fears of breast cancer patients in order to reduce anxiety while recognizing that treatment recommendations are desired by most women.

A major tyrosine-phosphorylated protein of Trypanosoma brucei is a nucleolar RNA-binding protein

We have previously identified a set of tyrosine-phosphorylated proteins with apparent molecular masses of 44-46 kDa as some of the major tyrosine phosphorylated species in the protozoan parasite Trypanosoma brucei. We now show that these molecules, herein named Nopp44/46, are localized in the nucleolus. Using monoclonal antibodies, we have isolated Nopp44/46 cDNA clones from expression libraries. Sequence analysis reveals that the predicted amino acid sequence of the molecule is composed of an N-terminal unique region, an internal acidic region, and C-terminal repeat region. Analysis of the cDNA clones and genomic Southern analysis indicated that Nopp44/46 belongs to a multigene family in which different gene copies are very similar but vary in the number of repeats. Interestingly, the repetitive amino acid sequence motif contains multiple RGG (Arg-Gly-Gly) boxes characteristic of RNA-binding proteins. In vitro binding experiments demonstrated that Nopp44/46 is indeed capable of binding nucleic acids. Competition experiments with different RNA homopolymers demonstrated that Nopp44/46 preferentially binds to poly(U). These studies suggest that Nopp44/46 may play a role in RNA metabolism in trypanosomes and raise the possibility that tyrosine phosphorylation may regulate the process.

Use of microsatellite loci to classify individuals by relatedness

This study investigates the use of microsatellite loci for estimating relatedness between individuals in wild, outbred, vertebrate populations. We measured allele frequencies at 20 unlinked, dinucleotide-repeat microsatellite loci in a population of wild mice (Mus musculus), and used these observed frequencies to generate the expected distributions of pairwise relatedness among full sib, half sib, and unrelated pairs of individuals, as would be estimated from the microsatellite data. In this population one should be able to discriminate between unrelated and full-sib dyads with at least 97% accuracy, and to discriminate half-sib pairs from unrelated pairs or from full-sib pairs with better than 80% accuracy. If one uses the criterion that parent-offspring pairs must share at least one allele per locus, then only 15% of full-sib pairs, 2% of half-sib pairs, and 0% of unrelated pairs in this population would qualify as potential parent-offspring pairs. We verified that the simulation results (which assume a random mating population in Hardy-Weinberg and linkage equilibrium) accurately predict results one would obtain from this population in real life by scoring laboratory-bred full- and half-sib families whose parents were wild-caught mice from the study population. We also investigated the effects of using different numbers of loci, or loci of different average heterozygosities (He), on misclassification frequencies. Both variables have strong effects on misclassification rate. For example, it requires almost twice as many loci of He = 0.62 to achieve the same accuracy as a given number of loci He = 0.75. Finally, we tested the ability of UPGMA clustering to identify family groups in our population. Clustering of allele matching scores among the offspring of four sets of independent maternal half sibships (four females, each mated to two different males) perfectly recovered the true family relationships.

Individualized Enhancement Programs for Nurses that Promote Competency

Working in a cost-conscious health care environment changes the accessibility to conferences, workshops and other continuing education offerings. Educators, employers and individual nurses are compelled to be innovative in their approach to maintaining competency through continuing education (CE). Greater emphasis must be placed on effectively matching CE programs with carefully targeted learning needs. This article illustrates a four-phase approach to an individualized enhancement program that incorporates job expectations and competencies. The phases are: 1) completing a needs assessment, 2) defining learning objectives, 3) assessing available learning resources, and 4) evaluating the CE experience.

Trypanosoma congolense: developmental regulation of protein kinases and tyrosine phosphorylation during the life cycle

In higher eukaryotes, key steps in the control of growth and proliferation are regulated by protein phosphorylation. However, little is known about the role of protein phosphorylation in the developmental cycles of pathogenic protozoa. In Trypanosoma brucei, only the bloodform and procyclic form stages can be obtained in sufficient numbers for biochemical analyses. However, the entire life cycle of Trypanosoma congolense can be generated in vitro, providing sufficient material for analyses of the different developmental stages. The studies reported here provide a series of snapshots documenting the activity of a number of protein serine/threonine kinases and the pattern of tyrosine-phosphorylated proteins throughout the T. congolense developmental cycle. Metacyclic forms and mammalian bloodforms showed similar profiles of protein kinase activity, as did procyclic forms and epimastigotes. Most tyrosine-phosphorylated proteins were shared between all developmental stages, with the exception of a 100-kDa metacyclic-specific species. The developmental changes in molecules involved in protein phosphorylation in the different developmental stages support the concept that changes in protein phosphorylation networks are important correlates of the developmental process in African trypanosomes.

Pharmacological aspects of acid secretion

The secretion of gastric acid is regulated both centrally and peripherally. The finding that H2-receptor antagonists are able to reduce or abolish acid secretion due to vagal, gastrinergic, and histaminergic stimulation shows that histamine plays a pivotal role in stimulation of the parietal cell. In the rat, the fundic histamine is released from the ECL cell, in response to gastrin, acetylcholine, or epinephrine, and histamine release is inhibited by somatostatin or by the H3-receptor ligand, R-alpha-methyl histamine. The parietal cell has a muscarinic, M3, receptor responsible for [Ca]i regulation. Blockade of muscarinic receptors by atropine can be as effective as H2-receptor blockade in controlling acid secretion. However, general effects on muscarinic receptors elsewhere produce significant side effects. The different receptor pathways converge to stimulate the gastric H+,K(+)-ATPase, the pump responsible for acid secretion by the stomach. This enzyme is an alpha,beta heterodimer, present in cytoplasmic membrane vesicles of the resting cell and in the canaliculus of the stimulated cell. It has been shown that acid secretion by the pump depends on provision of K+Cl- efflux pathway becoming associated with the pump. As secretion occurs only in the canaliculus, this K+Cl- pathway is activated only when the pump inserts into the canalicular membrane. Transport by the enzyme involves reciprocal conformational changes in the cytoplasmic and extracytoplasmic domain. These result in changes in sidedness and affinity for H3O+ and K+, enabling active H+ for K+ exchange. The acid pump inhibitors of the substituted benzimidazole class, such as omeprazole, are concentrated in the canaliculus of the secreting parietal cell and are activated there to form sulfenamides. The omeprazole sulfenamide, for example, reacts covalently with two cysteines in the extracytoplasmic loops between the fifth and sixth transmembrane and the seventh and eighth transmembrane segments of the alpha subunit of the H+,K(+)-ATPase, forming disulfide derivatives. This inhibits ATP hydrolysis and H+ transport, resulting in effective, long-lasting regulation of acid secretion. Therefore, this class of acid pump inhibitor is significantly more effective and faster acting than the H2 receptor antagonists. K+ competitive antagonists bind to the M1 and M2 transmembrane segments of the alpha subunit of the acid pump and also abolish ATPase activity. These drugs should also be able to reduce acid secretion more effectively than receptor antagonists and provide shorter acting but complete inhibition of acid secretion.

Three genes and two isozymes: gene conversion and the compartmentalization and expression of the phosphoglycerate kinases of Trypanosoma (Nannomonas) congolense

The glycosome, a microbody organelle found only in kinetoplastid protozoa, compartmentalizes the first six enzymes of glycolysis. In order to better understand the regulation and targeting of glycolytic enzymes in trypanosomes, we have cloned and analyzed the three genes of the phosphoglycerate kinase (PGK) complex of Trypanosoma (Nannomonas) congolense. The organization of the genes within the complex is similar to that of Trypanosoma brucei brucei. The nucleotide and amino-acid sequences, including those of the novel high-molecular-weight 56PGK, show substantial cross-species similarity. However, the two downstream genes, c1PGK and c2PGK, encode identical isozymes in T. congolense, while they encode distinct glycosomal and cytoplasmic isozymes in T. brucei. Western analysis also indicated that there are only two isozymes in T. congolense and that these are constitutively expressed. Differential digitonin solubilization of the trypanosomes indicated that 56PGK is primarily localized to the glycosome, as expected, and that c1/c2PGK is cytoplasmic. Northern analysis demonstrates that while 56PGK is constitutively expressed, c1PGK and c2PGK mRNAs are differentially expressed in the T. congolense developmental stages. This work demonstrates that T. congolense has only one PGK isozyme, 56PGK, that is predominantly localized in glycosomes.

Crystallisation of alpha-crustacyanin, the lobster carapace astaxanthin-protein: results from EURECA

Crystallisation of alpha-crustacyanin, the lobster carapace astaxanthin-protein was attempted under microgravity conditions in EURECA satellite using liquid-liquid diffusion with polyethyleneglycol (PEG) as precipitant; in a second reaction chamber phenol and dioxan were used as additives to prevent composite crystal growth. Crystals of alpha-crustacyanin grown under microgravity from PEG were larger than those grown terrestrially in the same apparatus under otherwise identical conditions. On retrieval, the crystals from PEG were shown to be composite and gave a powder diffraction pattern. The second reaction chamber showed leakage on retrieval and had also been subjected to rapid temperature variation during flight. Crystal fragments were nevertheless recovered but showed a powder diffraction pattern. It is concluded, certainly for liquid-liquid diffusion using PEG alone, that, for crustacyanin, although microgravity conditions resulted in an increase in dimensions of crystals, a measurable improvement in molecular ordering was not achieved.