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ABSTRACTFYCO1 (FYVE and coiled-coil domain containing 1) is an adaptor protein, expressed ubiquitously and required for microtubule-dependent, plus-end-directed transport of macroautophagic/autophagic vesicles. We have previously shown that loss-of-function mutations in FYCO1cause cataracts with no other ocular and/or extra-ocular phenotype. Here, we show fyco1homozygous knockout (fyco1−/−) mice recapitulate the cataract phenotype consistent with a critical role of FYCO1 and autophagy in lens morphogenesis. Transcriptome coupled with proteome and metabolome profiling identified many autophagy-associated genes, proteins, and lipids respectively perturbed in fyco1−/−mice lenses. Flow cytometry of FYCO1(c.2206C>T) knock-in (KI) human lens epithelial cells revealed a decrease in autophagic flux and autophagic vesicles resulting from the loss of FYCO1. Transmission electron microscopy showed cellular organelles accumulated in FYCO1(c.2206C>T) KI lens-like organoid structures and in fyco1−/−mice lenses. In summary, our data confirm the loss of FYCO1 function results in a diminished autophagic flux, impaired organelle removal, and cataractogenesis.Abbreviations:CC: congenital cataracts; DE: differentially expressed; ER: endoplasmic reticulum; FYCO1: FYVE and coiled-coil domain containing 1; hESC: human embryonic stem cell; KI: knock-in; OFZ: organelle-free zone; qRT-PCR: quantitative real-time PCR; PE: phosphatidylethanolamine; RNA-Seq: RNA sequencing; SD: standard deviation; sgRNA: single guide RNA; shRNA: shorthairpin RNA; TEM: transmission electron microscopy; WT: wild type

While research exists on parent expectations associated with post-school outcomes of youth with intellectual disability, limited research examines issues of parent—and youth—post-school expectations relative to issues of community, such as living in rural versus urban or suburban settings. Through a secondary analysis of the National Longitudinal Transition Study (NLTS) 2012, we examined parent and youth expectations regarding post-school outcomes for students with intellectual disability relative to school locale (i.e., rural, urban, and suburban) and severity of intellectual disability. Youth from rural schools reported high rates of positive post-school expectations with regard to independent living and being employed, and their rates relative to independent living exceeded parental expectations. However, across the different variables, school locale was only a factor in the binary or ordinal logistic regression analyses for two dependent variables: parental expectation for their child to support themselves financially and parental expectations of obtained level of education.

Precision-guided munitions are of interest to the Army as a means of both reducing collateral damage and increasing the chance of desired effect with the first round fired. Many technical barriers must be overcome to effectively guide a gun-launched projectile. Gun tubes are rifled to impart the appropriate spin to gyroscopically stabilize a statically unstable projectile. Extremely high spin rates complicate the guidance problem for precision-guided munitions. Manoeuvres achieved through some control mechanism must be actuated at the projectile spin rate. Few control mechanisms have been developed for spin-stabilized projectiles. A novel manoeuvre concept is introduced in this effort. The effectiveness of this concept was investigated through a fundamental derivation of flight mechanics and aerodynamic modelling. This derivation and simulation implementation was verified with existing six degree-of-freedom methods. The manoeuvrability of the airframe and power requirements was assessed by the development of a flight control law. Results suggest sufficient manoeuvrability since the control authority is larger than the ballistic dispersion. The guided airframe exhibited no dynamic flight instabilities. Estimates of the power requirements were within current battery technology and size constraints.

A computational and mathematical approach is used to investigate the effect of canard stall on projectile roll and pitch damping. For spinning projectiles with dithering canards, large angles of attack can be achieved by these canards. These large angles of attack can lead to stall that causes abnormal loads on the projectile. Because of these abnormalities, it is important to include the effects of stall on the projectile. First, the total roll and pitch moments of two canards is derived. These equations are then analysed to show that the effects of canard stall can produce a decrease in roll damping, causing roll rate to increase, and an increase in pitch damping, causing the no roll frame pitch rate to decrease. To validate this analysis, simulation is performed using a fully non-linear six-degree-of-freedom dynamic model with canard aerodynamics. The results from the simulation agree with the equations derived; thus, for projectiles that use dithering canards for control, it is important to include these non-linear effects in the projectile dynamic model.

Global positioning system (GPS) is a widely accepted means of navigation, whether it is for civilian or military means. With the implementation of GPS on smart projectiles, these weapons have been able to achieve remarkable accuracy. Even though the improvements in accuracy are impressive, GPS signals are susceptible to jamming and spoofing by a sufficiently motivated enemy. The work reported here examines the viability of constructing a navigation solution using ground-based signals of opportunity that provide range and range rate information. Using a generalized sensor model encompassing the key error terms, a variety of physical devices are included in the analysis. For a typical indirect fire trajectory, navigation solutions are computed as a function of the number and density of signal sources, terrain type, and sensor errors. Results indicate that navigation solutions can be computed with the same accuracy as current GPS systems with a moderate number of signal sources. Generally, more accurate solutions are obtained when the projectile is directly over the signal sources and there is a variation of signal source location in all three axes.

Weapon designers have known for some time that projectiles with low static margin have proven to be more susceptible to launch perturbations than comparable projectiles with high static stability, and that low static margin allows greater control authority. The work reported here examines a mechanism for active static margin control in flight through mass centre modification, demonstrating that such a system has significant impact on required manoeuvre control force to achieve a given control authority. A system is developed wherein a mass translates aft during flight inside a cavity aligned with the projectile centre-line, thereby altering the mass centre. This in turn decreases the projectile's static margin after launch and allows greater control authority later in flight, while at the same time decreasing initial throw-off errors. A seven-degree-of-freedom flight dynamic model is used to predict the performance of the system. Results show that by decreasing static margin after launch the projectile is less susceptible to launch perturbations and has increased control authority through the remainder of flight, leading to a smart projectile that outperforms rigid projectiles that are highly stable or highly manoeuvrable. This smart weapon feature is particularly attractive when the maximum control force and moment are small, and therefore is developed specifically for controllable munitions rather than missiles, which often exhibit ample control authority.

A polycrystalline phospholipid monolayer self-assembled at the surface of an air microbubble in aqueous solution represents a novel material structure:  in essence, a solid shell of wax with micrometer-scale dimensions and a thickness of only a single molecule. Micropipet manipulation of these microparticles revealed the dependence of the mechanical properties of the lipid shells, specifically, yield shear and shear viscosity, on the composition, grain microstructure, and thermal processing of the material, in particular the cooling rate of the shells from the melt. Properties were measured as a function of the (1) lipid composition at a fixed cooling rate and (2) cooling rate at a fixed lipid composition. Epifluorescent microscopy and transmission electron microscopy revealed that the morphology of the 1,2-distearoyl-sn-glycero-3-phosphatidylcholine monolayer microstructure, which develops upon freezing from the melt, is dependent on the cooling rate through the lipid transition temperature Tm, with larger micrograins being formed at slower cooling rates. Mechanical properties of the lipid shell follow micrograin size, with the coarse grain structure exhibiting a higher resistance to shear deformation than the fine grain structure does, which is behavior consistent with that of more traditional bulk crystalline materials.

A two‐year‐old cat was involved in a road traffic accident. Survey abdominal radiographs and urinary function were considered unremarkable. Six weeks later the cat presented with a palpable dorsal abdominal mass. Radiography revealed a soft tissue opacity mass caudal to the right kidney. Ultrasonography revealed a cyst‐like structure with moderately echogenic contents, and right‐sided hydronephrosis. There was no excretion of contrast medium from the right kidney after intravenous urography. Surgery revealed a disrupted right ureter adherent to the retroperitoneal mass. The mass contained serosanguineous fluid consistent with extravasated urine. Ureteronephrectomy was performed. The majority of the mass was excised and the cavity ablated. Histopathology of the excised tissue revealed a thick fibrous wall with no epithelial lining, consistent with a urinoma, which is thought to have developed as a consequence of ureteral trauma. The cat was clinically well three months postoperatively.

A significant number of casualties in previous conflicts died from peripheral vascular wounds. A well-designed tourniquet could possibly have prevented these deaths. The objective of this study was the identification of such a tourniquet. A survey of Special Operations corpsmen established important characteristics necessary in an ideal tourniquet. Because most available devices do not and patented ideas could not meet these criteria, a number of prototypes were developed. Seven potentially satisfactory tourniquets were evaluated by 15 Navy SEAL corpsmen. The success and timing of placement were recorded, and a follow-up questionnaire was completed. Of the several successful tourniquets, two were preferred. Tourniquets incorporating a windlass technique take longer to place and often fail when placed with only one hand. New, relatively simple tourniquet devices incorporating bladder and ratchet mechanisms can significantly improve tourniquet performance.

Records for fifteen species of stoneflies (Amphinemura sulcicollis, Nemoura avicularis, Nemoura cinerea, Nemurella pictetii, Protonemura meyeri, Leuctra fusca, Leuctra hippopus, Leuctra inermis, Capnia atra, Capnia bifrons, Diura bicaudata, Isoperla grammatica, Perla bipunctata, Chloroperla tripunctata and Siphonoperla torrentium) from the Corrib catchment basin in the west of Ireland are presented. Their distributional patterns are considered in relation to habitat characteristics, including water chemistry, and the general topographical and geological features of the area. Predation by fish on stoneflies in alkaline streams was also investigated.

Fragments of intact rat, pig and bovine lenses and isolated membranes from bovine lenses were examined by freeze-fracture-etch electron microscopy employing samples ultra-rapidly frozen in the absence of fixatives or cryoprotectants. Complementary replicas of the bovine outer cortex clearly display small patches of square arrays (6.6 nm repeat) as structures distinct from gap junctions in the same membranes. In the outer cortex square arrays appear in single membranes where the extracellular space is not thinned, whereas gap junctions, as in other tissues, only occur where the extracellular space is greatly attenuated. Square arrays in the middle cortex appear as patches of varying size surrounded by smooth membrane fracture faces. Within the undulating membranes of tongue-and-groove interdigitations in the inner cortex and nucleus, the square arrays are extensive and are located specifically on the regions which have convex curvature toward the cytoplasm. Square crystalline regions alternate with non-crystalline regions within each membrane of an undulating pair. Across the extracellular space, crystalline regions are matched with non-crystalline regions, thus making it unlikely that the square array participates in intercellular communication. Because the undulations occur in isolated membranes following urea washing to remove cytoplasmic and extrinsic membrane proteins, the square arrays probably play a crucial role in the formation of the undulations and in the maintenance of membrane curvature. X-ray diffraction experiments show reflections from the crystalline square array for all twenty of our preparations of isolated membranes. These x-ray experiments indicate that the square arrays observed by freeze-fracture are abundant in lens fiber cell membranes.

Galactose neuropathy is characterized by progressive endoneurial edema manifested by a gradual increase in endoneurial fluid pressure. Edema accumulates via a unique mechanism of osmotic force generated by products of the polyol pathway, synthesized within the endoneurial compartment. This paper presents morphologic findings showing firstly, that blood nerve barrier permeability to horseradish peroxidase complexes appears unchanged and secondly, peripheral nerve edema in this condition is restricted to extraganglionic endoneurium sparing the spinal ganglia and adjacent roots. Thirdly, mast cells accumulated in significant numbers and electron microscopy revealed degranulation. There was no evidence of edema in Schwann cell cytoplasm, the putative site of galactitol accumulation via the sorbitol pathway. These findings are discussed with respect to diabetic neuropathy for which galactose intoxication is a useful experimental model.

Three experiments were conducted to examine the effect of dietary arginine on urinary orotic acid excretion and the relationship between orotic aciduria and the cat's dietary arginine requirement. In the first experiment, diets containing 1.66 or 0.83% arginine were compared for their ability to sustain growth and food intake and prevent orotic aciduria. Growth and food intake were similar for each diet but the cats fed the 0.83% arginine excreted seven times as much orotic acid as those fed the 1.66% arginine. In the second experiment, diets containing 0.2, 0.4, 0.6, 0.8 and 1.0% arginine were compared for their ability to support growth and food intake and to prevent citric and orotic aciduria. Growth and food intake were optimized with arginine as 0.8% of the diet. Over the range of 0.4--1% arginine, orotic acid excretion was inversely related to the level of arginine, also orotate excretion of cats fed all levels of arginine was greater than that recorded in cats given 1.66% dietary arginine. The estimated level of dietary arginine required to minimize orotic acid excretion was 1.05%, which is 0.3% in excess of that required for maximum growth. Citrate excretion did not respond to dietary arginine level. In the third experiment, cats receiving a commercial cat food containing 1.74% arginine did not show orotic aciduria.

The distribution and type of fiber cell damage was evaluated in human age-related nuclear cataracts and in aged normal (non-cataractous) lenses. Ten age-related nuclear cataracts (53 to 89 years old) and four normal lenses (59 to 67 years old) were examined by electron microscopy of fixed Vibratome sections. Images from the adult, juvenile, fetal and embryonic nuclear regions were compared. Each cataractous lens contained a central region of increased light scattering which involved the embryonic and fetal regions with progressively less involvement in the juvenile and adult nuclear regions. Some damaged fiber cells were observed in all specimens, although damage was minor and infrequent in the normal lenses. Degeneration of single or groups of fiber cells was noted in all the adult nuclei of the cataractous lenses, becoming less frequent in the juvenile nuclei. The types of damage included localized voids, multilamellar membrane aggregates, globular bodies, enlarged cells and regions of highly convoluted membranes. The fetal and embryonic nuclei of the cataractous lenses exhibited rare and minor morphological defects, and were virtually identical to the equivalent regions of the normal aged lenses. Examination of cell interfaces in opaque regions of cataractous lenses revealed that the oldest fiber cells sustained apparent membrane loss. Extracellular spaces in the embryonic, fetal and juvenile regions of the cataractous lenses often contained dense deposits, presumably cytoplasmic material lost from adjacent fibers. The results indicate that the region of greatest nuclear opacity, located in the lens center, does not contain any significant cellular damage. This suggests that older fiber cells respond differently to pathological and senescent changes than younger cells made after fetal development. The observed loss of membranes and cytoplasmic material from the oldest fiber cells may be a contributory mechanism in the formation of age-related human nuclear cataracts.

Purpose. The goal of this study was to compare the ultrastruc-ture of the oldest cells in opaque and transparent human lenses.Methods. Age-related nuclear cataracts, late-onset diabetic nuclear cataracts and normal aged lenses were examined by transmission electron microscopy. Cross-sectional profiles of fiber cells in the embryonic, fetal and juvenile nuclear regions were obtained to facilitate direct comparisons between lens regions and between sample groups. Image analysis was performed to determine cross-sectional areas of fiber cells in each region.Results. The average cross-sectional area increased approximately sixfold from the outer to the inner nuclear regions in all lenses measured. In each nuclear region, fiber cells displayed a characteristic size, shape, arrangement and type of interdig-itations which were consistently seen in all the lenses examined. Some lenses had more complex interdigitations than others. Gap junctions were identified as pentalamellar structures having 16 nm width and appeared identical throughout the nuclei of both normal and cataractous lenses. The cytoplasm of all lenses was smooth and free of large density variations. However, the cytoplasm of some cataractous lenses appeared more granular in texture than noncataractous lenses. Cellular degeneration, debris or large cellular defects were not seen in the cores of cataractous lens nuclei.Conclusions. These results indicate that only minor ultrastruc-tural differences exist between the oldest fiber cells in normal and cataractous lenses, and that the presence of extensive cellular damage and disruptions is not necessary for the generation of nuclear opacities in aged lenses. Our observations suggest that light scattering sufficient for vision impairment may involve structural alterations much smaller than previously proposed.

α1-Acid glycoprotein (AAG) obtained from ascites and/or pleural fluids exhibited anti-heparin effects in platelet-poor plasma when evaluated by activated partial thromboplastin (Activated Thrombofax Reagent) and heparin-thrombin clotting time assays. An anti-heparin effect for AAG was also demonstrable in platelet-rich plasma (PRP) challenged with thrombin, but only over a limited range of heparin concentrations; at elevated heparin concentrations, and only in the presence of AAG, both platelet aggregation and clot formation were substantially inhibited. However, no detectable anti-heparin effect was observed following challenge of PRP with Activated Thrombofax Reagent; indeed, the anti-coagulant effect of heparin appeared synergistically amplified in these systems containing AAG, and AAG exhibited platelet pro-aggregate and pro-coagulant properties in the absence of heparin. The platelet pro-aggregating activity of AAG, though independent of heparin, appeared to require the onset of the coagulation cascade prior to the generation of thrombin; in the absence of such initiation, AAG remained a potent inhibitor of platelet activation.

Purified lac permease, the 46.5-kDa product of the lac Y gene that catalyzes lactose/H+ symport, or purified cytochrome o, a terminal oxidase of the Escherichia coli respiratory chain composed of four subunits with a composite molecular mass of 140 kDa, was reconstituted into proteoliposomes individually or in combination. The preparations were then examined by freeze-fracture electron microscopy employing conventional platinum/carbon replicas or by means of a new technique using thin tantalum replicas. In nonenergized proteoliposomes, both proteins appear to reconstitute as monomers based on (i) the variation of intramembrane particle density with protein concentration; (ii) the ratio of particles corresponding to each protein in proteoliposomes reconstituted with a known ratio of permease to oxidase; and (iii) the dimensions of the particles observed in tantalum replicas. The intramembrane particle diameters in tantalum replicas are about 20-25% smaller than those observed in conventional platinum/carbon replicas, indicating that the dimensions of the particles revealed with tantalum more accurately reflect the sizes of lac permease and cytochrome o. The diameters and heights of the permease and cytochrome o in tantalum replicas are 5.1 nm × 2.8 nm and 7.4 nm × 4.2 nm, respectively. Furthermore, a higher percentage of lac permease molecules exhibits a notch or cleft in tantalum replicas relative to platinum/carbon replicas. Importantly, the initial rate of lactose/H+ symport in proteoliposomes varies linearly with the ratio of lac permease to phospholipid, and no change is observed in either the size or distribution of lac permease molecules when the proteoliposomes are energized. The results taken as a whole provide a strong indication that both lac permease and cytochrome o reconstitute into proteoliposomes as monomers, that the permease does not dimerize in the presence of the H+ electrochemical gradient, and that both molecules are completely functional as monomers.

Freeze-fracture electron microscopy has been used to examine defect structures such as confocal domains, screw dislocations, disclinations, and walls in lamellar phospholipid phases containing known amounts of water (from about 5 to 65% by weight). In a concurrent study (Costello and Gulik-Krzywicki 1976) all samples were examined by X-ray diffraction before and after freeze-quenching to ensure that the freezing process had not induced a phase transition. Most of the prominent defect structures, especially confocal domains, have been observed in all samples. Electron micrographs showing the lamellar arrangements of the defects near their cores are presented. The most important observation about the frequency of occurrence of defects is the proliference of screw dislocations and the absence of edge dislocations. This lends support to the commonly proposed hypothesis that the deformation of smectic layers tends to occur at constant layer thickness.

Three independent assay methods were used to investigate the activities of antimicrobial peptides (human and rabbit defensins and protegrin from porcine leukocytes) against Mycobacterium tuberculosis in vitro. M. tuberculosis H37Ra was cultured in the presence of human neutrophil peptide 1, synthetic rabbit neutrophil peptide 1, or porcine protegrin 1 at 37 degrees C for 6 to 48 h, and antimycobacterial activity was measured by CFU assay. These peptides at a concentration of 50 microg/ml showed significant antibacterial effects on M. tuberculosis after 24 and 48 h of incubation (85.9 to 97.5% at 24 h and 91.6 to 99.4% at 48 h). A radiometric method and a radial diffusion assay confirmed these observations. Antibacterial activity against M. tuberculosis was independent of calcium (1.0 mM) or magnesium (1.0 mM) and not inhibited by sodium chloride (100 mM). The optimal pH for antibacterial activity against M. tuberculosis was greater than 4.0. Three clinical isolates of M. tuberculosis were also studied, and these peptides showed 86.3 to 99.0% reduction in CFU of these organisms. Morphological studies using scanning electron microscopy showed that defensins caused lesions on the surface of H37Ra. These observations suggest that antimicrobial peptides such as defensins and protegrins may represent an important component of the host defense mechanism against M. tuberculosis and offer a potential new approach to therapy.

Junctions between fiber cells of bovine lenses have been isolated in milligram quantities, without using detergents or proteases. The structure of the isolated junctions has been studied by thin-section, negative-stain, and freeze-fracture electron microscopy and by x-ray diffraction. The junctions are large and most often have an undulating surface topology as determined by thin sectioning and freeze-fracture. These undulations resemble the tongue-and-groove interdigitations between lens fiber cells previously seen by others (D. H. Dickson and G. W. Crock, 1972, Invest. Ophthalmol. 11:809-815). In sections, the isolated junctions display a pentalamellar structure approximately 13-14 nm in overall thickness, which is significantly thinner than liver gap junctions. Each junctional membrane contains in the plane of the lipid bilayers distinct units arranged in a square lattice with a center-to-center spacing of 6.6 nm. Freeze-fracture replicas of the junctions fractured transversely show that the repeating units extend across the entire thickness of each membrane. Each unit is probably constructed from four identical subunits, with each subunit containing a protein of an apparent molecular weight of 27,000. We conclude that the lens junctions are structurally and chemically, different from gap junctions and could represent a new kind of intercellular contact, not simply another crystalline state of the gap junction protein.

Mouse 3T6 cells were transformed with a chimeric DNA plasmid, pSVMgpt, in which the mouse mammary tumor virus (MMTV) promoter was fused to the Escherichia coli gene encoding xanthine-guanine phosphoribosyl transferase (Eco gpt). The transformants exhibited glucocorticoid-inducible expression of Eco gpt. With limiting xanthine concentrations, conditions were established in which cell growth became hormone dependent. Cells selected for their ability to grow in limiting concentrations of both xanthine and glucocorticoids contained amplified levels of Eco gpt DNA, and expression of Eco gpt remained glucocorticoid inducible in these amplified cells. Thus, amplification of the MMTV promoter region in itself did not abolish hormonal responsiveness of a gene. In addition to increased levels of Eco gpt DNA, some of the selected cells also exhibited increased levels (two- to threefold) of glucocorticoid receptors. Lastly, we found that excessive expression of Eco gpt is toxic to 3T6 cells; by maintaining low hormone levels and, therefore, low levels of expression, we were able to select cells with amplified Eco gpt. Thus, the MMTV promoter may be of general utility in expressing genes whose products may be lethal if they are produced in excessive quantities.

Overproduction of the sn-glycerol-3-phosphate acyltransferase in Escherichia coli leads to incorporation of this integral membrane protein into ordered tubular arrays within the cell. Freeze-fracture-etch shadowing was performed on suspensions of partially purified tubules and whole bacteria. This procedure revealed the presence of ridges and grooves defining a set of long-pitch left-handed helical ridges. The long-pitch helices represented chains of acyltransferase dimers. Tubules observed within the cell were often closely packed, with an apparent alignment of grooves and ridges in adjacent tubules. Fracture planes passing through the tubules indicated the presence of a bilayer structure, with some portion of the enzyme being associated with the membrane. The major portion of the enzyme extended from the hydrophilic surface, forming a large globular structure that, in favorable views, displayed a central cavity facing the cytoplasm. Computer analysis of shadowed tubules revealed that the left-handed helices were six stranded, with a pitch of 1,050 A (105.0 nm) and a spacing of 75 A (7.5 nm) between acyltransferase dimers along the chains. Analysis of the predicted secondary structure failed to reveal obvious transmembrane segments, suggesting that very little of the protein was inserted into the bilayer.

Proteoliposomes reconstituted with purified lac carrier protein from Escherichia coli were ultra-rapidly frozen and examined by freeze-fracture-etch electron microscopy. The proteoliposomes are greater than 95% unilamellar, and the majority are 30-150 nm in diameter. Fracture faces of proteoliposomes (at a protein:lipid molecular ratio of about 1:2500) display 7.0-nm diameter globular intramembrane particles uniformly distributed on convex and concave surfaces. Calculations of particle composition suggest that each intramembrane particle probably contains one or two molecules of the 46.5-kDa transmembranous lac carrier protein, depending on the correction factor for the thickness of the metal deposited to form the platinum/carbon replicas. Etched surfaces of the proteoliposomes are smooth. Incubation of the proteoliposomes with monoclonal antibody 4B1, which binds to an epitope in the lac carrier on the exterior of the proteoliposomes, dramatically alters the intramembrane particle distribution. After incubation with antibody, the convex (inner monolayer) fracture faces are nearly devoid of intramembrane particles, and an overall 4-fold reduction in the total number of intramembrane particles is observed.

A lysozyme isolated from the milk of a monotreme, the echidna, Tachyglossus aculeatus multiaculeatus, has been crystallized (space group P21, with unit‐cell dimensions a= 37.1, b= 42.0, c= 38.1 Å, β = 91° and Z= 2) and the structure refined to an Rvalue of 0.167 for all measured data in the resolution range 7.0–1.9 Å. It had previously been inferred from sequence homology with α‐lactalbumins that echidna milk lysozyme (EML) would bind one calcium ion per molecule. This has been confirmed in the present study in which the largest peak in a difference Fourier synthesis is associated with a calcium ion. The calcium binding site of EML is very similar to that observed in baboon and human α‐lactalbumins, and in a human lysozyme engineered to contain a calcium‐binding site. The overall fold of the protein is similar to that of chick‐type lysozymes. EML, like pigeon lysozyme, has only 125 residues terminating at a cysteine but in EML this forms a disulfide with a cysteine at residue 9 whereas the equivalent cysteine residue in all other lysozymes of known sequence occurs at position 6. These changes cause some minor structural rearrangements. The binding of calcium appears to have had little effect on the polypeptide backbone conformation and caused only small changes in the conformation of side chains coordinating the calcium ion. A homology modelling study [Acharya, Stuart, Phillips, McKenzie & Teahan (1994). J. Protein Chem.13(6), 569–584] correctly predicted the overall structure of EML and the nature of its calcium binding site but generally failed to model some more subtle differences observed in the EML structure as evidenced by the fact that the homology model more closely resembles the starting structure from which the model was derived than it does the crystal structure.

A diffraction study is reported of highly oriented samples of the smectic A mesophases of bis(p-n-hexyloxyphenyl)mercury (BHPM), ethyl p-azoxybenzoate (EPAB), and thallium stearate (TLST). Data were collected from stepped drops for the latter two compounds. Distortions of the first kind make a significant contribution to the lattice imperfections in these mesophases, while distortions of the second kind are less important than anticipated for such fluid materials. After correction for distortions, the structure amplitudes of the sharp meridional reflections decrease monotonically with order. The rate of decrease followed the order BHPM>EPAB>TLST, hence the numbers of reflections which could be collected were 2,3 and 6, respectively. Least-squares refinement of one to three parameters for proposed model structures was used to best fit the observed structure amplitudes. No suitable representation could be obtained using a two parameter model for the smectic phase of BHPM, but those of the other two materials were well satisfied by a three parameter model. This involves a centro-symmetric dimer motif having the two molecules displaced 6 to 7 Å along their long axes, and the dimer tilted with respect to the normal to the smectic layers so that the ends of the molecules overlap the smectic planes by less than 1 Å. This structure contradicts the commonly held view concerning the distinction between smectic A and C phases, according to which the molecules are perpendicular to the layers in the former and tilted in the latter.

SummarySampleite from Jingemia Cave, Watheroo (30° 16' S. 116° 00° E.), 190 km north of Perth, Western Australia is derived from the alteration of copper sulphides in contact with guano deposits. Associated minerals are atacamite, weddellite, and gypsum on goethite and manganese-oxide-coated friable quartz rock. Birnessite, halite, dolomite, taranakite, todorokite, apatite, and malachite are also present.The sampleite occurs as platy spheroidal aggregates to 0·3 mm with D3·20±0·01, a1·625 ? [010], ßand ?1·674, all ±0·002, aTurquoise Green 41d to Light Blue-Green 39d, ßand ?Benzol Green 41 to Venice Green 41b, absorption a< ß= ?, 2Va5–10°. Chemical analyses are given.Cu3(PO4)2·3H2O, a corrosion product reported on artifacts, is believed to be sampleite. A further occurrence of sampleite has been recorded from Brookton, 120 km ESE. of Perth. The structurally related mineral lavendulan has been reported from five Western Australian localities.

The goals were to define the clinical and morphological characteristics of cataract formation in the OXYS strain of rats which are genetically susceptible to oxidative stress. The predominately inherited feature is the high cellular level of glucose uptake. The OXYS strain displays pathological changes in many tissues including blood vessels, liver and lung, which are consistent with increased oxidative damage. Early cataract formation is a prominent feature of this strain.Rats were examined periodically from birth through the development of mature cataracts with slit lamp biomicroscopy. The morphology of selected stages of cataract development was studied using light and transmission electron microscopy (TEM) as well as immunohistochemical localization of lipid oxidation and DNA oxidation products. Lenses from normal rats of the same age were used as controls. OXYS rats developed cataracts as young as two weeks of age with progression to maturity by one year. Clinically, cataracts appeared initially as either nuclear or subcapsular cortical changes and developed into pronounced nuclear cataracts within months.

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