bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of an in vitro model for evaluating the interface between skin and percutaneous biomaterials
Authors: Fukano Yuko , Knowles Negar G. , Usui Marcia L. , Underwood Robert A. , Hauch Kip D. , Marshall Andrew J. , Ratner Buddy D. , Giachelli Cecilia , Carter William G. , Fleckman Philip , Olerud John E.
Published: August 2006

Percutaneous devices play an essential role in medicine; however, they are often associated with a significant risk of infection. One approach to circumvent infection would be to heal the wound around the devices by promoting skin cell attachment. We used two in vitro assay models to evaluate cutaneous response to poly(2‐hydoxyethyl methacrylate) (poly(HEMA)). One approach was to use a cell adhesion assay to test the effects of surface modification of poly(HEMA), and the second used an organ culture system of newborn foreskin biopsies implanted with porous poly(HEMA) rods (20 μm pores) to evaluate the skin/poly(HEMA) interface. Surface modification of poly(HEMA) using 1,1′‐carbonyldiimidazole (CDI) enhanced keratinocyte, fibroblast, and endothelial cell adhesion. Keratinocytes in the organ culture model not only remained functionally and structurally viable as observed by immunohistochemistry and electron microscopy, but migrated into the pores of CDI‐modified poly(HEMA) rods. No biointegration was seen in the non‐CDI‐modified poly(HEMA). Laminin 5 immunostaining was seen along the poly(HEMA)/skin interface in a pattern resembling the junctional epithelium of the tooth, the unique natural interface between the skin and tooth that serves as a barrier to bacteria. In vitro systematic evaluation of biomaterials for use in animal implant studies is both cost effective and time efficient.
Identification of differentially expressed genes in scarless wound healing utilizing polymerase chain reaction‐ suppression subtractive hybridization
Authors: Kathju Sandeep , Satish Latha , Rabik Cara , Rupert Terra , Oswald Duane , Johnson Sandra , Hu Fen Ze , Christopher Post J. , Ehrlich Garth D.
Published: August 2006

Wound healing in fetal skin is well known to proceed without scarring, whereas adult (postnatal) skin wound healing is accompanied by scar formation. To identify differentially expressed genes during fetal wound (FW) healing, we have used polymerase chain reaction‐suppression subtractive hybridization. This technique allows for a comparative analysis across the entire transcriptome of FW vs. unwounded fetal control tissue, including even potentially novel sequences. Our subtractive hybridization protocol identified 15 clones that are overexpressed in healing FWs, and 20 clones that are underexpressed. These include genes with both known and unknown functions. We have confirmed the differential pattern of expression for four of these candidate genes: elongation factor 1 α, elongation initiation factor 4e, and two transcripts thus far known only as an expressed sequence tags. With this approach, we have also identified novel genes potentially involved in scarless wound healing.
Antibiotic prescribing for chronic skin wounds in primary care
Authors: Howell‐Jones Rebecca S. , Price Patricia E. , Howard Anthony J. , Thomas David W.
Published: August 2006

The aim of this study was to describe and quantify systemic antibiotic prescribing for patients with chronic skin wounds presenting at the primary care, nonspecialist setting. Data for 1 year were extracted from a general practice morbidity database comprising approximately 185,000 patients attending family medical practitioners in Wales. Patients with chronic wounds (PCW) were identified using Read Codes and compared with nonwound patients who were randomly selected after matching for age‐band, sex, and general practice. PCW received a significantly greater number of antibiotic courses than nonwound patients (p<0.001). This increased level of prescribing was evident for flucloxacillin, co‐amoxiclav, cefaclor, cefalexin, erythromycin, trimethoprim, metronidazole, and ciprofloxacin (p<0.01 for all). While PCW also had a significantly higher prevalence of diabetes (16.5% compared with 6.6%, p<0.001), and attended at general practice significantly more frequently than nonwound patients (median (interquartile range) of 25 (17–40) visits per year compared with 12 (4–20), p<0.001), importantly, exclusion of diabetic patients and analysis of the proportion of visits on which patients received antibiotics did not affect the significance of the difference in antibiotic consumption. These data show a strong association between occurrence of chronic wounds and prescribing of antibiotics in primary health care, and wide variation in the type and duration of antibiotic therapy for chronic wounds. Further work is now indicated to rationalize this prescribing and determine the role that this exposure to antibiotics plays in the prevalence of antibiotic resistance in this at‐risk elderly population.
Use of photographs for the identification of pressure ulcers in elderly hospitalized patients: validity and reliability
Authors: Russell Localio A. , Margolis David J. , Kagan Sarah H. , Lowe Robert A. , Kinosian Bruce , Abbuhl Stephanie , Kavesh William , Holmes John H. , Ruffin Althea , Baumgarten Mona
Published: August 2006

To evaluate the ability of research nurses to identify pressure ulcers, the authors assembled digital photographs of the skin of 160 consenting elderly patients (80% African American, 63% women). The series included 39 photos of pressure ulcers, 109 of normal skin, and 12 of other skin conditions, determined by consensus by two experts (D.J.M. and S.H.K.). Photos were packaged electronically into eight blocks of 20, with pressure ulcer prevalence ranging from 20% to 30% per block. The eight blocks were duplicated to create two sets of 160 photos each. Each of six raters (experienced clinical research nurses), working independently, evaluated the 320 photos as if each photo depicted a different patient. For analysis, the ratings were collapsed into binary determinations (any pressure ulcer vs. none). The overall sensitivity and specificity of the ratings were 0.97 (95% confidence interval: 0.94, 0.98) and 0.81 (95% confidence interval: 0.77, 0.86), respectively. Rater‐specific prevalence (range: 31.8–47.5%) exceeded the true prevalence (24.4%). Inter‐ and intrarater reliability coefficients were 0.69 and 0.84, respectively. Trained research nurses can accurately classify pressure ulcers from photographs, even when patients are largely non‐White and the photographs depict pressure ulcers spanning all pressure ulcer stages.
Evaluation of Apligraf® persistence and basement membrane restoration in donor site wounds: a pilot study
Authors: Hu Shasa , Kirsner Robert S. , Falanga Vincent , Phillips Tania , Eaglstein William H.
Published: August 2006

Apligraf® is a bilayered tissue‐engineered product consisting of a bovine collagen matrix with neonatal fibroblasts, overlaid by a stratified epithelium containing living keratinocytes. The United States Food and Drug Administration has approved its use for venous leg ulcers and neuropathic diabetic foot ulcers. Apligraf® provides a dermal matrix and produces cytokines similar to the human skin. However, its mechanism of action and ultimate fate in host wounds are unclear. The aim of this study was to evaluate the persistence of Apligraf® fibroblasts and keratinocytes in human acute partial‐thickness wounds (split‐thickness donor sites) treated with Apligraf®. In an open‐label, within‐patient, three‐centered, controlled pilot study, 10 patients were treated with Apligraf®, Apligraf® dermis only (without epidermis), and a polyurethane film for donor site wounds of the same size, depth, and anatomical location. Apligraf® DNA persistence was the primary outcome measure. Basement membrane components, cosmetic outcome, time to wound healing, and safety parameters were secondary outcome measures. One week after the initial treatment, reverse transcription polymerase chain reaction analysis found that two Apligraf® and two Apligraf® dermis‐only‐treated sites had Apligraf® DNA present. Four weeks posttreatment, only one Apligraf® and one Apligraf® dermis‐only sites showed the presence of Apligraf® DNA. There was no difference between the three treatment modalities in establishing basement membrane in donor site wounds. No differences in other secondary outcomes were found. Apligraf® DNA persisted in a minority of patients at 4 weeks in acute partial‐thickness wounds. Apligraf®'s success in speeding healing of acute wounds appears to be related to factors other than the persistence of donor DNA or effect on basement membrane restoration.
Development of a porcine incisional wound model and novel scarring scales
Authors: Singer Adam J. , McClain Steve A.
Published: August 2006

A major goal of wound management is to reduce scarring. Prior to evaluating novel anti‐scarring therapies, we developed a porcine incisional wound model and scarring outcome measures. Forty‐eight full‐thickness incisions (3 cm in length) and excisional wounds (3 × 0.5 cm) were created on two animals and closed with sutures (n=24) or tissue adhesive (n=24). Scars were evaluated using two validated clinical scar scales and a novel scale developed for animals. Full‐thickness biopsies were obtained at 5 and 8 weeks for determination of scar morphology using H&E and Congo red staining with and without polarized light. Scar tissue was classified based on the collagen fiber morphology and “redness” ratio, which is a measure of the relative distribution of collagen fiber in all three spatial dimensions. The clinical cosmetic scales were highly reliable, yet nondiscriminatory. The novel gross cosmetic and histomorphological scores were both highly reliable (0.75 and 0.70, respectively), yet poorly correlated with each other (0.17). The “redness” ratio and cross‐sectional surface area measurements were also highly reliable (r=0.96 and 0.99, respectively) but unrelated to cosmetic outcomes. However, the “redness ratio” did correlate with the histomorphologic appearance of the scars, with poorer appearing clinical scars receiving lower ratios (ANOVA p=0.001). Significant differences in cosmetic scores were noted between excisional and incisional wounds favoring incisions (p=0.0019). We describe a novel porcine model for incisional and excisional wounds. The new clinical and histomorphologic outcomes were highly reliable yet poorly correlated. In general, incisional wounds healed with less apparent scarring than excisional wounds.
A role for decorin in cutaneous wound healing and angiogenesis
Authors: Järveläinen Hannu , Puolakkainen Pauli , Pakkanen Sari , Brown Eric L. , Höök Magnus , Iozzo Renato V. , Sage E.Helene , Wight Thomas N.
Published: August 2006

Decorin is known to influence tissue tensile strength and cellular phenotype. Therefore, decorin is likely to have an impact on tissue repair, including cutaneous wound healing. In this study, cutaneous healing of both excisional and incisional full‐thickness dermal wounds was studied in decorin‐deficient (Dcn−/−) animals. A statistically significant delay in excisional wound healing in the Dcn−/− mice occurred at 4 and 10 days postwounding and, in incisional wounds at 4, 10, and 18 days when compared with wild‐type (Dcn−/−) controls. Fibrovascular invasion into polyvinylalcohol sponges was significantly increased by day 18 in Dcn−/− mice relative to Dcn+/+ mice. The 18‐day sponge implants in the Dcn−/− mice showed a marked accumulation of biglycan when compared with the corresponding implants in Dcn+/+ mice. Thus, regulated production of decorin may serve as an excellent therapeutic approach for modifying impaired wound healing and harmful foreign body reactions.
Biological fate and clinical implications of arginine metabolism in tissue healing
Authors: Curran John N. , Winter Des C. , Bouchier‐Hayes David
Published: August 2006

Since its discovery in 1987, many biological roles (including wound healing) have been identified for nitric oxide (NO). The gas is produced by NO synthase using the dibasic amino acid l‐arginine as a substrate. It has been established that a lack of dietary l‐arginine delays experimental wound healing. Arginine can also be metabolized to urea and ornithine by arginase‐1, a pathway that generates l‐proline, a substrate for collagen synthesis, and polyamines, which stimulate cellular proliferation. Herein, we review subjects of interest in arginine metabolism, with emphasis on the biochemistry of wound NO production, relative NO synthase isoform activity in healing wounds, cellular contributions to NO production, and NO effects and mechanisms of action in wound healing.
Bone marrow‐derived mesenchymal stromal cells accelerate wound healing in the rat
Authors: McFarlin Kellie , Gao Xiaohua , Liu Yong Bo , Dulchavsky Deborah S. , Kwon David , Arbab Ali S. , Bansal Mona , Li Yi , Chopp Michael , Dulchavsky Scott A. , Gautam Subhash C.
Published: August 2006

Bone marrow‐derived mesenchymal stromal cells (BMSCs) are multipotential stem cells capable of differentiation into numerous cell types, including fibroblasts, cartilage, bone, muscle, and brain cells. BMSCs also secrete a large number of growth factors and cytokines that are critical to the repair of injured tissues. Because of the extraordinary plasticity and the ability of syngeneic or allogeneic BMSCs to secrete tissue‐repair factors, we investigated the therapeutic efficacy of BMSCs for healing of fascial and cutaneous incisional wounds in Sprague–Dawley rats. Systemic administration of syngeneic BMSCs (2 × 106) once daily for 4 days or a single treatment with 5 × 106 BMSCs 24 hours after wounding significantly increased the wound bursting strength of fascial and cutaneous wounds on days 7 and 14 postwounding. Wound healing was also significantly improved following injection of BMSCs locally at the wound site. Furthermore, allogeneic BMSCs were as efficient as syngeneic BMSCs in promoting wound healing. Administration of BMSCs labeled with iron oxides/1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethylindocarbocyanine perchlorate fluorescent dye revealed that systemically administered BMSCs engraft to the wound. The increase in the tensile strength of wounds treated with BMSCs was associated with increased production of collagen in the wound. In addition, BMSC treatment caused more rapid histologic maturation of wounds compared with untreated wounds. These data suggest that cell therapy with BMSCs has the potential to augment healing of surgical and cutaneous wounds.
Timing the commitment to a wound‐healing response of denervated limb stumps in the adult newt, Notophthalmus viridescens
Authors: Salley‐Guydon Judith D. , Tassava Roy A.
Published: August 2006

Adult newt limbs that are denervated 1 day after amputation undergo a wound‐healing response and, although they become reinnervated, will not regenerate unless reinjured. Experiments were designed to determine when denervated limb stumps of adult newts become committed to a wound‐healing response. In Experiment I, limbs were amputated and denervated 1 day after amputation. On days 7, 14, 21, 28, and 35 days after the initial amputation and denervation, stumps were reamputated to remove the distal tip. This design varied the time the distal stump was devoid of nerves before reamputation. None of the limbs reamputated at 7 days regenerated. About half of the limbs reamputated at 14 days regenerated and almost all of those reamputated at days 21, 28, and 35 regenerated. In Experiment II, limbs were denervated and then amputated on day 7 or 14, at two different levels. Limbs with a short stump became innervated earlier and regeneration occurred more frequently at both levels of amputation. The results of these experiments show that denervated limb stumps become committed to a wound‐healing response between days 7 and 14 after amputation/denervation. If sufficient nerves arrive before day 7, a regeneration response is initiated. If the stump is denervated for 14 days or longer, commitment to wound healing occurs and ingrowing nerves cannot initiate a regeneration response.
Effect of Hypothyroidism on the NO/cGMP Pathway of Corpus Cavernosum in Rabbits
Authors: Kilicarslan Hakan , Bagcivan Ihsan , Yildirim M. Kemal , Sarac Bulent , Kaya Tijen
Published: August 2006

Introduction

The incidence of hormonal dysfunction as a cause of impotence remains controversial. However, several recent studies have reported evidence of hormonal abnormalities in 25–35% of impotent men. Hypothyroidism has been reported to occur in 6% of impotent men. There is some evidence suggesting that hypothyroidism may be a cause of impotence.

Aim

We aimed to investigate the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway in hypothyroidism in an experimental rabbit model and compared hypothyroid rabbits with controls to evaluate the possible involvement of the NO/cGMP pathway.

Methods

The study comprised 20 male New Zealand white rabbits. The rabbits were divided into two equal groups. The first group had hypothyroidism induced surgically by thyroidectomy for 6 weeks. The second group underwent a sham operation.

Results

There was no significant change in the mean body weight of hypothyroid rabbits and controls. Triiodothyronine and thyroxine levels were significantly lower in hypothyroid rabbits. Plasma thyroid-stimulating hormone and prolactin levels were significantly higher in hypothyroid rabbits. Plasma total calcium and parathormone levels remained in the normal range in both groups.

Main Outcome Measures

Papaverine-induced concentration-dependent relaxations were similar in both groups. Carbachol-induced relaxation responses decreased in hypothyroid rabbits. There were significant differences between control and hypothyroid rabbits in frequency-dependent relaxations induced by electrical-field stimulation (EFS). YC-1-induced relaxation responses did not change significantly in hypothyroid rabbits. Concentration-dependent relaxations induced by diethylamine (DEA)/NO were similar in both groups. Amrinone-induced relaxation responses did not change significantly in hypothyroid rabbits.

Conclusion

Reductions of relaxant responses to EFS and carbachol in hypothyroid rabbits can depend on the decrease of released or synthesized NO from nitrergic nerves and endothelium.
Comparison of Androgens in Women with Hypoactive Sexual Desire Disorder: Those on Combined Oral Contraceptives (COCs) vs. Those Not on COCs
Authors: Warnock Julia K. , Clayton Anita , Croft Harry , Segraves Robert , Biggs Faye C.
Published: August 2006

Introduction

Approximately one out of four sexually active women in the United States uses some form of hormonal contraceptive method because they provide the most effective reversible method of birth control available. However, little attention has been paid to possible adverse effects of combined oral contraceptives (COCs) on sexual functioning.

Aims

The aim of this study was to examine the potential effects of COCs on women with hypoactive sexual desire disorder (HSDD). It was hypothesized that female patients with generalized, acquired HSDD on COCs have lower androgen levels than those not on COCs.

Methods

The patients were healthy premenopausal women with HSDD, aged 22–50 years. Subjects had a history of adequate sexual desire, interest, and functioning. Participants were required to be in a stable, monogamous, heterosexual relationship and were screened for any medication or medical or psychiatric disorders that impact desire. The patients met operational criteria for global, acquired HSDD. The 106 patients were divided into two groups: those on COCs (N = 43) and those not on COCs (N = 63). A two-tailed t-test comparison was made between the two groups comparing free and total testosterone and sex hormone-binding globulin (SHBG).

Main Outcome Measures

The main outcome measures are the differences between the two groups comparing free testosterone, total testosterone, and SHBG.

Results

These patients with HSDD on COCs had significantly lower free and total testosterone levels compared with those who were not on COCs. The SHBG was significantly higher in the group on COCs compared with those who were not on COCs.

Conclusion

The result of this study suggests that COCs in premenopausal women with HSDD are associated with lower androgen levels than those not on COCs. Further research is required to determine if low androgen levels secondary to COCs impact female sexual desire.
A rigorous yet simple quantitative risk assessment method for quarantine pests and non‐native organisms
Authors: Holt J. , Black R. , Abdallah Roshan
Published: August 2006

Internationally recognised guidelines for the assessment of risk posed by non‐native organisms generally suggest that the assessment is disaggregated into a series of components each being scored and then the scores added or averaged to give the final result. Assigning odds instead of scores allows a more rigorous probabilistic treatment of the data, which can offer more effective discrimination between organisms. For each component of the assessment, the odds express how likely is the evidence if the organism poses a risk as a quarantine pest. According to Bayesian theory, the odds for all components are multiplied together and the product divided by itself plus one to give the probability that the organism poses a risk as a quarantine pest given the evidence available (assuming that the prior probability is neutral). A general illustration of the different distributions of outcomes obtained from score averaging and probability is provided. The approach is then applied to a set of risk assessments for 256 potential quarantine pests compiled for Tanzania in 1997. The greater discrimination between cases may help improve communication between risk assessment scientists and regulatory decision makers.
Ultrastructure and embryonic development of a syconoid calcareous sponge
Authors: Eerkes‐Medrano Dafne I. , Leys Sally P.
Published: August 2006

Abstract. Recent molecular data suggest that the Porifera is paraphyletic (Calcarea+Silicea) and that the Calcarea is more closely related to the Metazoa than to other sponge groups, thereby implying that a sponge‐like animal gave rise to other metazoans. One ramification of these data is that calcareous sponges could provide clues as to what features are shared among this ancestral metazoan and higher animals. Recent studies describing detailed morphology in the Calcarea are lacking. We have used a combination of microscopy techniques to study the fine structure of Syconcoactum Urban 1905, a cosmopolitan calcareous sponge. The sponge has a distinct polarity, consisting of a single tube with an apically opening osculum. Finger‐like chambers, several hundred micrometers in length, form the sides of the tube. The inner and outer layers of the chamber wall are formed by epithelia characterized by apical–basal polarity and occluding junctions between cells. The outer layer—the pinacoderm—and atrial cavity are lined by plate‐like cells (pinacocytes), and the inner choanoderm is lined by a continuous sheet of choanocytes. Incurrent openings of the sponge are formed by porocytes, tubular cells that join the pinacoderm to the choanoderm. Between these two layers lies a collagenous mesohyl that houses sclerocytes, spicules, amoeboid cells, and a progression of embryonic stages. The morphology of choanocytes and porocytes is plastic. Ostia were closed in sponges that were vigorously shaken and in sponges left in still water for over 30 min. Choanocytes, and in particular collar microvilli, varied in size and shape, depending on their location in the choanocyte chamber. Although some of the odd shapes of choanocytes and their collars can be explained by the development of large embryos first beneath and later on top of the choanocytes, the presence of many fused collar microvilli on choanocytes may reflect peculiarities of the hydrodynamics in large syconoid choanocyte chambers. The unusual formation of a hollow blastula larva and its inversion through the choanocyte epithelium are suggestive of epithelial rather than mesenchymal cell movements. These details illustrate that calcareous sponges have characteristics that allow comparison with other metazoans—one of the reasons they have long been the focus of studies of evolution and development.
Ultrastructural study of the epidermis in two free‐living Platyhelminthes, Mesostoma viaregginum and M. productum (Rhabdocoela, Typhloplanida)
Authors: Culioli Julia‐Laurence
Published: August 2006

Abstract. The epidermis of the free‐living typhloplanids Mesostoma viaregginum and M. productum (Mesostominae) is described. In both species, the epidermis has polarized cells with nuclei located at the basal part of the cell, whereas mitochondria are in the apical one. The epidermis is entirely covered by microvilli and locomotory cilia anchored in the cytoplasm by vertical and horizontal rootlets. Rootlets exhibit distinct length and periodic structure in the two species. Furthermore, in each species vertical and horizontal rootlets possess different periodic structure. The pattern of termination of microtubules in epidermal cilia is described for the first time in the Typhloplanida; central microtubules shift along one axonemal side, doublets 1 and 6–9 lose their microtubule B, and gradually peripheral doublets become singlets. Finally, an electron‐dense material caps the tip of the cilia. This pattern of termination closely resembles that of Temnocephalida, Kalytorhynchia, and Dalyelliida examined so far, but differences exist.
Morphology and biological roles of spicule networks in Cadlina luteomarginata (Nudibranchia, Doridina)
Authors: Penney Brian K.
Published: August 2006

Abstract. Many cryptobranch dorid nudibranchs contain innumerable calcareous spicules, yet the function of these elements is unknown. Two possible roles are defense against predators and structural support. In one dorid, Cadlina luteomarginata, whole‐mount and thin‐section staining revealed an intricate network of spicule tracts and connective tissue ramifying throughout the body, with muscle fibers associated with this spicule/connective tissue matrix and inserting into it. Spicules were present in high concentrations in all areas of the body, but highest in exterior mantle tissue. Relative investment increased isometrically with body size for most body regions, in contrast to the positively allometric investment seen in prosobranch shells. Bioassays with artificial food indicated that spicules alone did not deter generalist crabs and anemones, and only weakly increased the deterrence of secondary chemicals to anemones. Thus, while nudibranch spicules may serve as a defense against other predators, their primary role may be in body support.
Structure and formation of the adventitious tube of the Japanese watering‐pot shell Stirpulina ramosa (Bivalvia, Anomalodesmata, Clavagellidae) and a comparison with that of the Penicillidae
Authors: Morton Brian
Published: August 2006

Abstract. Stirpulina ramosa is the only extant endobenthic representative of the Clavagellidae and is restricted to the waters of Japan. A single intact adventitious tube of this species has been obtained and its structure is described. The right valve is 16 mm long and located within the adventitious tube. It has an opisthodetic ligament located on resilifers. There are anterior and posterior adductor muscle scars, a thick pallial line, and pallial and pedal gape (right valve only) sinuses. The left shell valve is but 9 mm long and is united into the fabric of the adventitious tube via the intermediary of a shelly saddle. Internally, only the anterior adductor muscle scar and a small element of the pallial line scar are identifiable on the left valve. The posterior adductor and the rest of the pallial line scar (including a pallial sinus) are, remarkably, located on the adventitious tube beyond the shell valve margin. The adventitious tube of S. ramosa is formed in a manner wholly dissimilar from that of Brechites vaginiferus (Penicillidae). In B. vaginiferus, the tube is secreted as a single entity from the general outer mantle surface, including the siphons, covering the body. As a consequence, both shell valves are incorporated into the structure of the tube and the watering pot is bilaterally symmetrical. In S. ramosa, the tube and watering pot are secreted from the mantle margin and surface surrounding and extending from the left shell valve, so that only the left valve is incorporated into its structure. A dorsally derived mantle element is progressively extended over to the right side of the body, meeting a ventrally derived counterpart that passes beneath it, forming a pleat in the calcareous structure of the right side of the tube that they secrete. This pleat extends into the complex of watering‐pot tubules and forms the pedal gape. The watering pot is thus Ω shaped. The ventrally derived mantle element forms a sinusoidal crest on the right‐hand base of the watering pot, creating a pedal gape sinus scar on the right valve. The Clavagellidae radiated widely in the Mesozoic, leaving behind a rich fossil record for Stirpulina. Only S. ramosa, however, has survived until the present. In contrast, the Cenozoic Penicillidae has a poor fossil record, but there is a rich variety of extant endobenthic watering‐pot shells. It has been argued hitherto that the two families represent a remarkable example of convergent evolution. In view of the success of the Penicillidae and thus the endobenthic, tube‐dwelling lifestyle, however, it is hard to understand why Stirpulina has largely died out—even S. ramosa being known by but one or two specimens. A study of the anatomy of S. ramosa might one day answer this question.
Is the aestivation of the earthwormHormogaster elisaea paradiapause?
Authors: Díaz Cosín Darío J. , Ruiz María Pilar , Ramajo Marta , Gutiérrez Mónica
Published: August 2006

Abstract.We report the results of a laboratory study of the aestivation ofHormogaster elisaeto determine the nature of the inactive period (diapause or quiescence) and to evaluate the influence of soil moisture, temperature, season, and earthworm body weight on the process. The results showed that specimens ofH. elisaeunderwent facultative diapause—paradiapause—characterized by the construction of aestivation chambers in which the animal coils up and its activity decreases. Soil moisture appeared to be the most important environmental factor involved in the onset of aestivation. Temperature and time of year also had some influence, but earthworm body weight appeared to have none. Aestivating earthworms showed a decrease of 41.6% in mean body weight. Once replaced in soil with 20% moisture content, they took 6.4±3.1 d to exit their chambers and another 6.5±3.6 d to recover their initial body weight.
Ultrastructure of the peduncular aesthetascs of Speleonectes tanumekes (Crustacea, Remipedia) in comparison with crustaceans from stressful environments
Authors: Van Der Ham Joris L. , Felgenhauer Bruce E.
Published: August 2006

Abstract. Osmotic stress associated with the freshwater environment and desiccation stress associated with the terrestrial environment may have a shortening effect on the length of the innervation of crustacean aesthetascs. Physical stress of the littoral environment may have a similar effect on the length of the cuticular portion of aesthetascs. The aesthetascs of crustaceans that inhabit these environments share a similar ultrastructural feature, which may help animals cope with these environmental stresses. This ultrastructural feature, the position of the basal bodies proximal to the lumen of the aesthetasc, is absent from the aesthetascs of crustaceans that occur in the typical marine environment. Interestingly, the ultrastructural feature associated with these stressful habitats is present in the peduncular aesthetascs of the remipede Speleonectes tanumekes, even though the environmental stresses that may invoke the reduction of aesthetascs are absent in the marine‐cave environment where this animal occurs. The importance of the sensitivity of aesthetascs for survival in this lightless environment may result in a selective pressure that favors basal bodies to be positioned proximal to the lumen of the aesthetasc.
Selective Peptide Chain Extension at the N‐terminus of Aspartic and Glutamic Acids Utilizing 1‐(N‐protected‐α‐aminoacyl)benzotriazoles
Authors: Katritzky Alan R. , Todadze Ekaterina , Cusido Janet , Angrish Parul , Shestopalov Alexander A.
Published: August 2006

Diverse N‐protected di‐(3a–d, 3a + a′, 5a–d, 5d + d′, and 7a–g) and tripeptides (10a–h) were synthesized under mild reaction conditions in good yields (65–97%) by acylation with 1‐(N‐protected‐α‐aminoacyl)benzotriazoles of the amino groups of free aspartic and glutamic acids. Complete retention of chirality was demonstrated by parallel experiments involving d‐Ala, l‐Ala, and dl‐Ala for the preparation of dipeptides and tripeptides, and supported by NMR and HPLC analyses.
FLIPPER RUBBING BEHAVIORS IN WILD BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS)
Authors: Sakai Mai , Hishii Toru , Takeda Shohei , Kohshima Shiro
Published: August 2006

Abstract

“Flipper rubbing” behavior was quantitatively analyzed in wild Indo‐Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island, Tokyo, Japan. We observed two types of flipper rubbing: (1) F‐B rubbing; one dolphin (Rubber) rubbed its flipper over various parts of a partner's (Rubbee) body, and (2) F‐F rubbing; both dolphins rubbed each other's anterior flipper edge in alternating shifts. F‐B rubbings tended to be initiated by the Rubbee and were terminated by the Rubber. The Rubbee often moved actively its body part that was in contact with the Rubber's flipper, and assumed side‐up, upside‐down, or other postures while the Rubber remained horizontal in most cases. These facts suggest that the Rubbee engaged in F‐B rubbing more actively than the Rubber, and might receive some benefit from the frictional contact during F‐B rubbing. Dolphins often switched their roles as Rubber and Rubbee between episodes of flipper rubbing bout. Adults and sub‐adults exchanged F‐B rubbing and F‐F rubbing most often with individuals of the same sex in the same age class. F‐B rubbing was frequent in mother‐and‐calf dyads. Our results suggest that flipper rubbing is an affiliative behavior which could be a quantitative measure of social relationships among individuals of this species in future studies.
REDUCED POPULATION GROWTH OF GRAY SEALS AT SABLE ISLAND: EVIDENCE FROM PUP PRODUCTION AND AGE OF PRIMIPARITY
Authors: Bowen W. D. , McMillan J. I. , Blanchard Wade
Published: August 2006

Abstract

Pup production on Sable Island, Nova Scotia, has been increasing exponentially since the early 1960s and by 1997 Sable Island was the largest gray seal colony worldwide. Using an aerial photographic survey, as in previous years, we estimated pup production in January 2004 to determine if this exponential rate of increase had continued. A total of 33,268 pups was counted on the color positives. When corrected for the proportion pups missed on the imagery (1.106 for the 12th; 1.527 on the 13th), the proportion of pups that died prior to the survey (0.031), and the proportion of pups born before the survey (east colony 0.966, west colony 0.962), estimated total pup production was 41,500 with SE = 4,381. The 2004 estimate indicates that pup production on Sable Island has continued to increase, but suggests that the rate of increase (r) may have declined (0.070 compared to previous 0.128). Females from the 1998–2000 cohorts were about 16 times less likely to give birth for the first time at age 4 yr and more than twice as likely at age 6 yr compared to those in the mid‐late 1980s. The new estimate of pup production and observed changes in age of primiparity provide the first indication of changes in vital rates of this population. However, additional estimates of pup production and vital rates are needed to confirm this conclusion and to investigate the underlying mechanisms.
Keystone rodent interactions: prairie dogs and kangaroo rats structure the biotic composition of a desertified grassland
Authors: Davidson Ana D. , Lightfoot David C.
Published: August 2006

Understanding the interactive effects of multiple keystone species where they co‐occur may have important consequences for regional biodiversity. Additionally, understanding how the impacts of keystone species vary across different ecosystems is important for effectively guiding conservation and management. We conducted a large‐scale field study in northern Mexico where the geographic distributions of black‐tailed prairie dogs Cynomys ludovicianus and banner‐tailed kangaroo rats Dipodomys spectabilis overlap. These species are considered both keystones and ecosystem engineers of grassland environments, but little is known about their separate and interacting roles in desertified systems where they co‐occur. Our research evaluated 1) the independent impacts of black‐tailed prairie dogs and banner‐tailed kangaroo rats in a desertified annual grassland, and 2) their interactive effects on grassland community structure and biodiversity. Prairie dogs and kangaroo rats differentially affected vegetation structure, plant cover, species composition, and species richness across multiple spatial and temporal scales. The interactive effects of these keystone species resulted in enhanced landscape heterogeneity and biodiversity. Our results demonstrate the importance of prairie dogs and kangaroo rats in desertified grasslands, and have important implications for understanding the interactive effects and context‐dependency of keystone species.
Evolution of Vitamin B2Biosynthesis: 6,7-Dimethyl-8-Ribityllumazine Synthases ofBrucella
Authors: Zylberman Vanesa , Klinke Sebastián , Haase Ilka , Bacher Adelbert , Fischer Markus , Goldbaum Fernando Alberto
Published: August 2006

The penultimate step in the biosynthesis of riboflavin (vitamin B2) involves the condensation of 3,4-dihydroxy-2-butanone 4-phosphate with 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is catalyzed by 6,7-dimethyl-8-ribityllumazine synthase (lumazine synthase). PathogenicBrucellaspecies adapted to an intracellular lifestyle have two genes involved in riboflavin synthesis,ribH1andribH2, which are located on different chromosomes. TheribH2gene was shown previously to specify a lumazine synthase (type II lumazine synthase) with an unusual decameric structure and a very highKmfor 3,4-dihydroxy-2-butanone 4-phosphate. Moreover, the protein was found to be an immunodominantBrucellaantigen and was able to generate strong humoral as well as cellular immunity againstBrucella abortusin mice. We have now cloned and expressed theribH1gene, which is located inside a small riboflavin operon, together with two other putative riboflavin biosynthesis genes and thenusBgene, specifying an antitermination factor. The RibH1 protein (type I lumazine synthase) is a homopentamer catalyzing the formation of 6,7-dimethyl-8-ribityllumazine at a rate of 18 nmol mg−1min−1. Sequence comparison of lumazine synthases from archaea, bacteria, plants, and fungi suggests a family of proteins comprising archaeal lumazine and riboflavin synthases, type I lumazine synthases, and the eubacterial type II lumazine synthases.
Expression of Yeast Mitochondrial Aconitase in
Bacillus subtilis
Authors: Serio Alisa W. , Sonenshein Abraham L.
Published: August 2006

Expression of yeast mitochondrial aconitase (Aco1) in a
Bacillus subtilis
aconitase null mutant restored aconitase activity and glutamate prototrophy but only partially restored sporulation. Late sporulation gene expression in the Aco1-expressing strain was delayed.
Bacillus subtilis
Aconitase Is Required for Efficient Late-Sporulation Gene Expression
Authors: Serio Alisa W. , Pechter Kieran B. , Sonenshein Abraham L.
Published: August 2006

Bacillus subtilis
aconitase, encoded by the
citB
gene, is homologous to the bifunctional eukaryotic protein IRP-1 (iron regulatory protein 1). Like IRP-1,
B. subtilis
aconitase is both an enzyme and an RNA binding protein. In an attempt to separate the two activities of aconitase, the C-terminal region of the
B. subtilis citB
gene product was mutagenized. The resulting strain had high catalytic activity but was defective in sporulation. The defect was at a late stage of sporulation, specifically affecting expression of σ
K
-dependent genes, many of which are important for spore coat assembly and require transcriptional activation by GerE. Accumulation of
gerE
mRNA and GerE protein was delayed in the aconitase mutant strain. Pure
B. subtilis
aconitase bound to the 3′ untranslated region of
gerE
mRNA in in vitro gel mobility shift assays, strongly suggesting that aconitase RNA binding activity may stabilize
gerE
mRNA in order to allow efficient GerE synthesis and proper timing of spore coat assembly.
ScoC and SinR Negatively Regulateeprby Corepression inBacillus subtilis
Authors: Kodgire Prashant , Dixit Madhulika , Rao K. Krishnamurthy
Published: August 2006

Negative regulation ofeprinBacillus subtilis168 is mediated jointly by both ScoC and SinR, which bind to their respective target sites 62 bp apart. Increasing the distance between the two sites abolishes repression, indicating that the two proteins interact, thereby suggesting a mechanism of corepression.
Antimutator Role of the DNA Glycosylase
mutY
Gene in
Helicobacter pylori
Authors: Huang Shuyan , Kang Josephine , Blaser Martin J.
Published: August 2006

Helicobacter pylori
has a highly variable genome with ongoing diversification via inter- and intragenomic recombination and spontaneous mutation. DNA repair genes modulating mutation and recombination rates that influence diversification have not been well characterized for
H. pylori
. To examine the role of putative base excision repair
ung
and
mutY
glycosylase and
xthA
apurinic/apyrimidinic endonuclease genes in
H. pylori
, mutants of each were constructed in strain JP26 by allelic exchange. Spontaneous mutation frequencies of JP26
mutY
mutants, assessed by rifampin resistance, were consistently higher (26-fold) than that of the wild type, whereas the
ung
and
xthA
mutants showed smaller increases. In
trans
complementation of the JP26
mutY
mutant restored spontaneous mutation frequencies to wild-type levels. In cross-species studies,
H. pylori mutY
complemented an
Escherichia coli mutY
mutant and vice versa. In contrast, the
ung
and
mutY
mutants did not show higher frequencies of intergenomic recombination or greater sensitivity to UV-induced DNA damage than the wild type. The
H. pylori mutY
open reading frame contains an eight-adenine homonucleotide tract; we provide evidence that this is subject to slipped-strand mispairing, leading to frameshifts that eliminate gene function. Our findings indicate that
H. pylori
possesses phase-variable base excision repair, consistent with a tension between repair and mutation.
Investigations into σ
B
-Modulated Regulatory Pathways Governing Extracellular Virulence Determinant Production in
Staphylococcus aureus
Authors: Shaw Lindsey N. , Aish Joanne , Davenport Jessica E. , Brown Melanie C. , Lithgow James K. , Simmonite Kay , Crossley Howard , Travis James , Potempa Jan , Foster Simon J.
Published: August 2006

The commonly used
Staphylococcus aureus
laboratory strain 8325-4 bears a naturally occurring 11-bp deletion in the σ
B
-regulating phosphatase
rsbU
. We have previously published a report (M. J. Horsburgh, J. L. Aish, I. J. White, L. Shaw, J. K. Lithgow, and S. J. Foster, J. Bacteriol. 184:5457-5467, 2002) on restoring the
rsbU
deletion, producing a σ
B
-functional 8325-4 derivative, SH1000. SH1000 is pleiotropically altered in phenotype from 8325-4, displaying enhanced pigmentation, increased growth yields, and a marked decrease in secreted exoproteins. This reduction in exoprotein secretion appears to result from a sixfold reduction in
agr
expression. In this study we have undertaken transposon mutagenesis of SH1000 to identify components involved in the modulation of extracellular proteases and α-hemolysin compared to 8325-4. In total, 13 genes were identified displaying increased α-hemolysin transcription and extracellular proteolysis. Phenotypic analysis revealed that each mutant also had decreased pigmentation and a general increase in protein secretion. Interestingly this phenotype was not identical in each case but was variable from mutant to mutant. None of the genes identified encoded classic regulatory proteins but were predominantly metabolic enzymes involved in amino acid biosynthesis and transport. Further analysis revealed that all of these mutations were clustered in a 35-kb region of the chromosome. By complementation and genetic manipulation we were able to demonstrate the validity of these mutations. Interestingly transcriptional analysis revealed that rather than being regulated by σ
B
, these genes appeared to have a role in the regulation of σ
B
activity. Thus, we propose that the loss of individual genes in this chromosomal hot spot region results in a destabilization of cellular harmony and disruption of the σ
B
regulatory cascade.
Genome Sequence and Global Gene Expression of Q54, a New Phage Species Linking the 936 and c2 Phage Species ofLactococcus lactis
Authors: Fortier Louis-Charles , Bransi Ali , Moineau Sylvain
Published: August 2006

The lytic lactococcal phage Q54 was previously isolated from a failed sour cream production. Its complete genomic sequence (26,537 bp) is reported here, and the analysis indicated that it represents a newLactococcus lactisphage species. A striking feature of phage Q54 is the low level of similarity of its proteome (47 open reading frames) with proteins in databases. A global gene expression study confirmed the presence of two early gene modules in Q54. The unusual configuration of these modules, combined with results of comparative analysis with other lactococcal phage genomes, suggests that one of these modules was acquired through recombination events between c2- and 936-like phages. Proteolytic cleavage and cross-linking of the major capsid protein were demonstrated through structural protein analyses. A programmed translational frameshift between the major tail protein (MTP) and the receptor-binding protein (RBP) was also discovered. A “shifty stop” signal followed by putative secondary structures is likely involved in frameshifting. To our knowledge, this is only the second report of translational frameshifting (+1) in double-stranded DNA bacteriophages and the first case of translational coupling between an MTP and an RBP. Thus, phage Q54 represents a fascinating member of a new species with unusual characteristics that brings new insights into lactococcal phage evolution.