Enhancing chlamydospore production in Duddingtonia flagrans on solid substrate: The impact of mannitol and varied cultivation conditions

Duddingtonia flagrans is a nematophagous fungus which has shown promising results as a non-chemical parasitic control tool. The fungus disrupts the parasite's life cycle by trapping larvae in the environment through the networks generated from chlamydospores, thus preventing the reinfection of animals. One barrier to the development of a commercial product using this tool is the need to increase chlamydospore production in the laboratory for its administration to livestock. The purpose of this study was to evaluate the addition of mannitol to an enriched culture medium and the effect of adverse cultivation conditions on chlamydospore production. D. flagrans was cultivated on Petri dishes with corn agar for 4 weeks at 27 °C and 70% relative humidity (RH). Four groups were then formed, all with Sabouraud agar as a base, to which different growth inducers were added: GSA (glucose Sabouraud agar), GSA-MI (glucose Sabouraud agar + meso inositol), GSA-E (enriched glucose Sabouraud agar), and AE-M (enriched agar + mannitol). After 4 weeks, chlamydospores were recovered by washing the surface of each plate with distilled water and then quantified. The medium that yielded the highest amount of chlamydospores was subjected to different cultivation conditions: NC (normal conditions): 70% RH and 27 °C, AC (adverse conditions) 1: 20% RH and 40 °C, CA2: 60% RH and 27 °C, and CA3: 55% RH and 24 °C. It was determined that mannitol increases chlamydospore production (65x106 chlamydospores/plate), and when reducing humidity by 10% under cultivation conditions it resulted in an approximately 10% increase in chlamydospore production compared to the control group. These results suggest that the addition of polyols, as well as its cultivation under certain environmental conditions, can improve chlamydospore production on a laboratory scale.

A review of the use of Duddingtonia flagrans as a biological controller of strongylid nematodes in horses

In horses, the nematodes of the Strongylidae family are the most important due to their prevalence and pathogenicity. Sanitary plans include parasite control based on chemical anthelmintics. Among these, the benzimidazole compounds have been used since the 1960s to control the nematode Strongylus vulgaris. Its inappropriate use resulted in the development of resistance in parasites with a shorter biological cycle, such as the small strongyles. Currently, the genera that make up this group show widespread resistance to all chemical treatments available in veterinary medicine, except for macrocyclic lactones, where less effective action has been detected. The need to find alternative routes for its control is recognized. International organizations and markets are increasingly restrictive in the allowed levels of drugs in products of animal origin, so one of the drawbacks is the permanence of chemical compounds in tissues. Therefore, other tools not chemically based are proposed, such as the biological control of gastrointestinal nematodes. Various research groups around the world have carried out tests on the control capacity of the nematophagous fungus Duddingtonia flagrans against this group of parasites. The objective of this review is to compile the different tests that are available on biological control in this species, in in vivo and in vitro tests, and the possible incorporation of this tool as an alternative method of antiparasitic control in an integrated control scheme of parasites.

Elizabethkingia miricola: an opportunistic pathogen in ICU

Background

The Elizabethkingia genus is formed by a group of bacteria which are widely distributed in nature. Elizabethkingia is not part of human microbiota, therefore is considered to be an opportunistic pathogen. In the last years, it has become a cause of potentially fatal disease, becoming an emerging bacteria of increasing relevance. The objective of this study is to describe the impact of Elizabethkingia bacteria in infected patients in the ICU of a hospital in Granada.

Methods

Descriptive study. Patients who have been isolated in a biological sample of Elizabethkingia miricola throughout the year 2.021 in the ICU of San Cecilio University Hospital in Granada. Date and place of isolation were registered. Other variables registered were sex, age, length of ICU stay, days between ICU admission and bacterium isolation, days between bacterium isolation and death, infection, cause of admission or cause of death.

Results

Bacterium was isolated in 15 patients. Cause of admission was COVID-19 in 73.3% of patients. 73.3% were men and 26.6% women.The average age was 56.9 years. The average length of ICU stay was 43.8 days. 4 patients were diagnosed with ventilator-associated pneumonia and 5 patients were diagnosed with tracheobronchitis.The average days between ICU admission and bacterium isolation was 26,4 days. The average days between mechanical ventilation and bacterium isolation was 25.9 days. 53.3% of patients died. The average days between bacteria isolation and death was 18.2 days.

Conclusions

Elizabethkingia miricola is an emerging bacterium under special vigilance due to its capacity to cause major morbidity and mortality in admitted patients in ICU. The rapid identification and the study of the antibiotic susceptibility is considered of special relevance so they can be correctly managed to avoid infections and complications resulting from this microorganism.

Key messages

• Elizabethkingia is a special surveillance bacterie due to its morbidity and mortality effects.

• Elizabethkingia could be a severity indicator in admitted patients to the ICU.

Overcoming multimorbidity: Chrodis Integrated Multimorbidity Care Model pilot implementation

Background

Multimorbidity (MM) has become one of the greatest challenges for patients and healthcare providers, calling for the development of care models that offer holistic, patient-centered care plans. Our objective was to assess the applicability and effectiveness of the Chrodis Integrated Multimorbidity Care Model (IMCM) to improve care for patients with MM in the Public Health System of Aragón, a region in northeastern Spain where MM affects 80% of people over 65 years of age.

Methods

We developed and implemented a set of actions (”change package”) to target three main improvement areas (i.e., care fragmentation, training of professionals and community care) covering all five dimensions of the model. We used key process and outcome indicators to evaluate each action, including healthcare service use (hospitalizations, emergency room visits), delivery of care (care plans, case managers), improvement in MM management skills of professionals (online training course), and patient self-perceived quality of care (ad-hoc questionnaire).

Results

291 patients of over 65 years of age with MM were recruited. At the end of the implementation every patient had a designated case manager and an individualized care plan, and 96.7% had their social situation assessed. During the 1-year pilot intervention, patients averaged 0.69 hospitalizations and 1.24 visits to the emergency room; 87.5% reported a self-perceived improvement of received care. 348 community resources were mapped and made available online in an official website. 89% of professionals who were offered to participate in the training programme agreed, reporting 8.3/10 satisfaction with the course, and improved their MM management skills from 7.36 to 9.18/10.

Conclusions

The IMCM is applicable in the context of the Spanish Public Health System and is effective in improving quality of care for patients and professionals alike.

Key messages

Reinforcing the mechanisms that integrate community, primary and hospital care is still necessary if we intend to reduce the negative health outcomes associated to care fragmentation in multimorbidity. The sustainability of the model requires the continued collaboration of key stakeholders and the awareness that multimorbidity is an issue that exceeds purely economic and structural barriers.

Overexpression of connexin 43 reduces melanoma proliferative and metastatic capacity

Background:

Alterations in connexin 43 (Cx43) expression and/or gap junction (GJ)-mediated intercellular communication are implicated in cancer pathogenesis. Herein, we have investigated the role of Cx43 in melanoma cell proliferation and apoptosis sensitivity in vitro, as well as metastatic capability and tumour growth in vivo.

Methods:

Connexin 43 expression levels, GJ coupling and proliferation rates were analysed in four different human melanoma cell lines. Furthermore, tumour growth and lung metastasis of high compared with low Cx43-expressing FMS cells were evaluated in vivo using a melanoma xenograft model.

Results:

Specific inhibition of Cx43 channel activity accelerated melanoma cell proliferation, whereas overexpression of Cx43 increased GJ coupling and reduced cell growth. Moreover, Cx43 overexpression in FMS cells increased basal and tumour necrosis factor-α-induced apoptosis and resulted in decreased melanoma tumour growth and lower number and size of metastatic foci in vivo.

Conclusions:

Our findings reveal an important role for Cx43 in intrinsically controlling melanoma growth, death and metastasis, and emphasise the potential use of compounds that selectively enhance Cx43 expression on melanoma in the future chemotherapy and/or immunotherapy protocols.

[Antifungal susceptibility of clinical isolates of Scopulariopsis species]

INTRODUCTION

Scopulariopsis is a common soil saprophyte. In the last years the infections caused by Scopulariopsis species have increased, included superficial and invasive mycoses. This fungi has been reported resistant in vitro to some antifungal agents, although there is little information about this. The aim of the study was to establish in vitro antifungal susceptibility of clinical isolates of Scopulariopsis species against to broad-spectrum antifungal agents.

METHODS

A total of 28 Scopulariopsis strains (10 S. brevicaulis, 7 S. koningii, 3 S. acremonium, 3 S. candida, 3 S. flava, 1 S. brumptii and 1 S. fusca) were tested using Sensititre Yeast One and broth microdilution methods to determine the minimum inhibitory concentrations (MICs) to amphotericin B, fluconazole, itraconazole, posaconazole, voriconazole and 5-fluorocytosine, and minimun effective concentration (MECs) to anidulafungin, caspofungin and micafungin.

RESULTS

Our data confirm the high in vitro resistance of Scopulariopsis to antifungal agents. Anidulafungin, caspofungin, micafungin (MICs ≥ 8 mg/L), 5-fluorocytosine (MICs ≥ 64 mg/L), and fluconazole (MICs ≥ 128 mg/L) were inactive in vitro in all species. MICs of amphotericin B (range 2 to ≥ 8 mg/L) and itraconazole (0.5 to ≥ 16 mg/L) were high. The best antifungal activity was observed for posaconazole and voriconazole (0.5 to ≥ 8 mg/L). With Sensititre Yeast One method MICs obtained slightly lower. Scopulariopsis candida, S. flava and S. fusca were the most resistant species, while S. acremonium and S. brevicaulis showed the lowest MICs.

CONCLUSIONS

MICs of all tested antifungal agents for Scopulariopsis were very high. Infections caused by Scopulariopsis species may not respond to antifungal treatment. Voriconazole is the drug of choice for treatment. We consider it appropriate to add amphotericin B in serious infections.

Microbial spoilage of meats offered for retail sale in Mexico City

Causes of the food borne epidemics in Mexico City have usually been ascribed to poor handling and preparation of foods. In this work, presence of microorganisms indicative of contamination were analysed in meat sold in Mexico City's retail outlets. Enterobacteriaceae, psycorothrophs, mould and yeast, and mesophile counts, were evaluated in meat from five animal species (beef, sheep, chicken, rabbit and horse). pH, recorded as spoilage indicator, was not significantly different among days of storage nor animal species, conversely, water holding capacity was significantly higher for horse meat. Mesophiles, psychrothrophs and Enterobacteriaceae counts were above legal limits in beef after 5 days of storage at 4°C. This was not observed in rabbit nor chicken meat. Mould and yeast populations remained constant until day 4. Moulds are seldom a problem, whereas yeasts play an important role in the alteration of flavour characteristics. In general, horse had the highest initial microbial counts.

Morphogenetic action through flux-limited spreading

A central question in biology is how secreted morphogens act to induce different cellular responses within a group of cells in a concentration-dependent manner. Modeling morphogenetic output in multicellular systems has so far employed linear diffusion, which is the normal type of diffusion associated with Brownian processes. However, there is evidence that at least some morphogens, such as Hedgehog (Hh) molecules, may not freely diffuse. Moreover, the mathematical analysis of such models necessarily implies unrealistic instantaneous spreading of morphogen molecules, which are derived from the assumptions of Brownian motion in its continuous formulation. A strict mathematical model considering Fick's diffusion law predicts morphogen exposure of the whole tissue at the same time. Such a strict model thus does not describe true biological patterns, even if similar and attractive patterns appear as results of applying such simple model. To eliminate non-biological behaviors from diffusion models we introduce flux-limited spreading (FLS), which implies a restricted velocity for morphogen propagation and a nonlinear mechanism of transport. Using FLS and focusing on intercellular Hh-Gli signaling, we model a morphogen gradient and highlight the propagation velocity of morphogen particles as a new key biological parameter. This model is then applied to the formation and action of the Sonic Hh (Shh) gradient in the vertebrate embryonic neural tube using our experimental data on Hh spreading in heterologous systems together with published data. Unlike linear diffusion models, FLS modeling predicts concentration fronts and the evolution of gradient dynamics and responses over time. In addition to spreading restrictions by extracellular binding partners, we suggest that the constraints imposed by direct bridges of information transfer such as nanotubes or cytonemes underlie FLS. Indeed, we detect and measure morphogen particle velocity in such cell extensions in different systems.

Inoculation of lactic acid bacteria on meat surfaces as a means of decontamination in semitropical conditions

Reduction of microbial populations on carcasses has been achieved and reported by some authors by spraying solutions of organic acids, mainly lactic acid, on the meat surface. However, in practice, lactic acid is very expensive. Production of lactic acid in situ by a controlled lactic fermentation seemed to be a feasible answer. The objective of the present study was to explore the viability of this concept at semitropical conditions, i.e. temperatures around 25°C. In a first experiment, seven starters were tested for their ability to produce lactic acid and reducing the growth rate of pseudomonads, taking these microorganisms as indicators of contamination by spoilage microorganisms. The lactic acid bacteria strains were isolated from native Mexican maize-based beverages, and inoculated on the meat surface. Addition of sucrose and wrapping the samples in PVC film in order to induce a microaerophilic environment encouraged the over-growth of L. bulgaricus and P. pentosaceous over pseudomonads. A second experiment was designed to test a mixture of these two strains and a commercial starter with respect to lactic acid production, overgrowth of lactic acid bacteria over pseudomonads, decolouration and oxidation of the meat samples. It was concluded that a commercial starter (L. plantarum + M. kristinae-varians) resulted in a reduction of pseudomonas growth rate, without notably affecting meat colour and degree of oxidation.

Engorda de corderos Pelibuey con diferente nivel de alfalfa en la dieta

El objetivo de este estudio fue evaluar el efecto de diferentes niveles de alfalfa (Medicago sativa L.) en la dieta de corderos sobre el comportamiento productivo, durante 11 semanas. Se utilizaron 36 corderos machos Pelibuey de 5 meses de edad, en estabulación, con peso inicial promedio de 22 kg, distribuidos homogéneamente en cuatro grupos de 3 animales cada uno, con 3 repeticiones por grupo. Los grupos fueron asignados al azar a cada uno de cuatro tratamientos evaluados: 0, 20, 30 y 40 % de alfalfa (base seca). Se utilizó un diseño completamente al azar, utilizando el Proc GLM (SAS, 1999) y cuando se observaron diferencias estadísticas, se realizó una comparación de medias utilizando la prueba de Tukey. Se determinó consumo de alimento, ganancia de peso, conversión, eficiencia alimenticia, rendimiento de canal en caliente y frio, y pH de la canal; además de la degradabilidad in situ de la MS de las dietas. El consumo de MS aumentó (p0,05), promediando 271 g animal-1 día-1. Tampoco hubo variación (p>0,05) en el peso final, conversión y eficiencia alimenticia, promediando 38,0 kg animal-1,4,74 y 0,212, respectivamente. El peso (19,3 y 18,8 kg) y rendimiento (54,4 y 53,0 %) de canal en caliente y fría, fueron similares entre tratamientos. Incluir alfalfa en la dieta de corderos, no ofrece ventajas en la ganancia de peso, sin embargo hasta 40 %, podría ser atractivo económicamente para el productor, además de promover mayor consumo de MS.

Strains of Staphylococcus aureus and pathology associated with chronic suppurative mastitis in rabbits

Staphylococcal mastitis is one of the main reasons for culling adult does from commercial rabbitries. The aim of this study was describe the spectrum of gross and microscopic lesions in 178 cases of chronic staphylococcal mastitis in adult does and to determine whether there is a correlation between Staphylococcus aureus genotypes and pathology. On the basis of histopathology, chronic mastitis was differentiated into abscesses (66.3%), suppurative mastitis with a lobular pattern (7.9%), cellulitis (19.6%) and mixed lesions (6.2%). Pathological presentations were not related to S. aureus genotype.

Seasonal trends and spatial relations between environmental/meteorological factors and leishmaniosis sand fly vector abundances in Central Spain

This paper reports on an entomological survey performed over the period 2006-2008 in Central Spain (mainly in the Madrid province) where canine leishmaniosis (CanL) is endemic. The study area was selected on the grounds of its wide altitude range, which determines both broad climate and vegetation ranges that could affect sand fly distributions. This area was surveyed from NE to SW across its mountain range (Sistema Central) and plateau area using sticky traps mainly on embankments. In 2006 and 2007, 123 sites were sampled (9557 sand flies captured) to establish possible relations between environmental or meteorological factors and vector densities (Phlebotomus perniciosus and Phlebotomus ariasi). The factors correlated with higher vector densities were: a sample site between villages or at the edge of a village, the lack of a paved road, a rural habitat, an east or south-facing wall or wall sheltered from the wind, the presence of livestock or birds, a holm-oak wood vegetation, a lower summer mean temperature and lower annual mean precipitation. This study was followed by a seasonal survey conducted at 16 selected sites (14,353 sand flies) sampled them monthly from May to November 2008. P. perniciosus showed a diphasic seasonal trend with two abundance peaks in July and September whereas P. ariasi showed a monophasic trend with one peak in August. Comparing with data from studies performed in 1991 in the same area, vector densities are significantly higher. A possible explanation for this is that the vectors (mainly P. ariasi) are moving towards higher altitudes perhaps because of global change. This increasing trend could have an impact on CanL and its geographical distribution.

[Neuraxial analgesia during labor in a patient with Arnold-Chiari type I malformation and syringomyelia]

Chiari type I malformation is a caudal displacement of the cerebellum with tonsillar herniation through the foramen magnum, frequently associated with syringomyelia, a syndrome characterized by cyst-like cavities in the spinal cord; each of the conditions leads to characteristic neurologic abnormalities. Pregnant patients with these types of malformation are considered to have an increased risk of brainstem compression and/or progression of the disease during labor. We present the case of a patient in labor with a diagnosis of syringomyelia associated with Chiari type I malformation and describe the anesthetic management. The patient revealed during labor that she had syringomyelia associated with Chiari type I malformation, after having made no mention of it in previous history taking. Finally, we review the pathology observed in these patients.

Micro/nano encapsulation via electrified coaxial liquid jets

We report a method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size. This compound jet is generated by the action of electro-hydrodynamic (EHD) forces with a diameter that ranges from tens of nanometers to tens of micrometers. The eventual jet breakup results in an aerosol of monodisperse compound droplets with the outer liquid surrounding or encapsulating the inner one. Following this approach, we have produced monodisperse capsules with diameters varying between 10 and 0.15 micrometers, depending on the running parameters.

TP53 polymorphism, HPV infection, and risk of cervical cancer

The role of a polymorphism at position 72 of the tumor suppressor gene TP53 in the development of cervical cancer is not well established. The arginine variant of the p53 protein could be more susceptible to degradation by human papillomavirus (HPV) E6 protein than the protein containing proline. Recent studies show controversial results. We investigated a possible association between TP53 polymorphism and cervical cancer in a Peruvian population with high prevalence of HPV infection. HPV status and TP53 polymorphism were determined for 119 cases of invasive cervical cancer and 127 control women from Peru. HPV infection was detected by PCR of cervical cells or tumor biopsies. For determination of TP53 polymorphism, exon 4 of the TP53 gene was amplified by PCR, and DNA was subsequently subjected to restriction enzyme digest. Associations between TP53 polymorphism, HPV infection, and cervical cancer were assessed using logistic regression. Women homozygotes for arginine had a 2.2-fold increased risk (95% confidence interval: 0.6-7.6) for cervical cancer. The odds ratio for women heterozygotes for Arg/Pro was 3.5 (95% confidence interval: 0.9-14). Similarly increased risks were found when restricting analysis to HPV-positive women only. The distribution of TP53 genotypes in this Peruvian population was comparable with that found in Caucasians. Our results cannot rule out an association between the TP53 polymorphism at codon 72, HPV infection, and the etiology of cervical cancer.

HPV types and cofactors causing cervical cancer in Peru

We conducted a hospital-based case-control study in Peru of 198 women with histologically confirmed cervical cancer (173 squamous cell carcinomas and 25 cases of adenocarcinoma/adenosquamous carcinoma) and 196 control women. Information on risk factors was obtained by personal interview. Using PCR-based assays on exfoliated cervical cells and biopsy specimens, HPV DNA was detected in 95.3% of women with squamous cell carcinoma and in 92.0% of women with adenocarcinoma/adenosquamous carcinoma compared with 17.7% in control women. The age-adjusted odds ratio was 116.0 (95% Cl = 48.6-276.0) for squamous cell carcinoma and 51.4 (95% Cl = 11.4-232.0) for adenocarcinoma/adenosquamous carcinoma. The commonest types in women with cervical cancer were HPV 16, 18, 31, 52 and 35. The association with the various HPV types was equally strong for the two most common types (HPV 16 and 18) as for the other less common types. In addition to HPV, long-term use of oral contraceptives and smoking were associated with an increased risk. HPV is the main cause of both squamous cell carcinoma and adenocarcinoma in Peruvian women.

The sterol-sensing domain of Patched protein seems to control Smoothened activity through Patched vesicular trafficking

The Hedgehog (Hh) family of signaling molecules function as organizers in many morphogenetic processes. Hh signaling requires cholesterol in both signal-generating and -receiving cells, and it requires the tumor suppressor Patched (Ptc) in receiving cells in which it plays a negative role. Ptc both blocks the Hh pathway and limits the spread of Hh. Sequence analysis suggests that it has 12 transmembrane segments, 5 of which are homologous to a conserved region that has been identified in several proteins involved in cholesterol homeostasis and has been designated the sterol-sensing domain (SSD). In the present study, we show that a Ptc mutant with a single amino acid substitution in the SSD induces target gene activation in a ligand-independent manner. This mutant Ptc(SSD) protein shows dominant-negative activity in blocking Hh signaling by preventing the downregulation of Smoothened (Smo), a positive effector of the Hh pathway. Despite its dominant-negative activity, the mutant Ptc protein functioned like the wild-type protein in sequestering and internalizing Hh. In addition, we show that Ptc(SSD) preferentially accumulates in endosomes of the endocytic compartment. All these results suggest a role of the SSD of Ptc in mediating the vesicular trafficking of Ptc to regulate Smo activity.

The development of the Drosophila genital disc

The imaginal discs of Drosophila melanogaster, which form the adult epidermal structures, are a good experimental model for studying morphogenesis. The genital disc forms the terminalia, which are the most sexually dimorphic structures of the fly. Both sexes of Drosophila have a single genital disc formed by three primordia. The female genital primordium is derived from 8(th) abdominal segment and is located anteriorly, the anal primordium (10 and 11(th) abdominal segments) is located posteriorly, and the male genital primordium from the 9(th) abdominal segment lies between them. In both sexes, only two of these three primordia develop to form the adult terminalia. The anal primordium develops in both sexes but, depending on the genetic sex, will form either male or female analia. However, only one of the genital primordia develops in each sex, forming either the male or the female genitalia. This depends on the genetic sex of the fly. Therefore, the genital disc is a very good experimental model of how the sex-determination and homeotic genes - which determine cell identity - interact to direct the development of a population of cells into male or female terminalia. It has been proposed that the sexually dimorphic development of the genital disc is the result of an integrated genetic input, made up by the sex-determination gene doublesex and the homeotic gene Abdominal-B. This input acts by modulating the response to Hedgehog, Wingless, and Decapentaplegic morphogenetic signals.

Sex determination genes control the development of the Drosophila genital disc, modulating the response to Hedgehog, Wingless and Decapentaplegic signals

In both sexes, the Drosophila genital disc contains the female and male genital primordia. The sex determination gene doublesex controls which of these primordia will develop and which will be repressed. In females, the presence of Doublesex(F) product results in the development of the female genital primordium and repression of the male primordium. In males, the presence of Doublesex(M) product results in the development and repression of the male and female genital primordia, respectively. This report shows that Doublesex(F) prevents the induction of decapentaplegic by Hedgehog in the repressed male primordium of female genital discs, whereas Doublesex(M) blocks the Wingless pathway in the repressed female primordium of male genital discs. It is also shown that Doublesex(F) is continuously required during female larval development to prevent activation of decapentaplegic in the repressed male primordium, and during pupation for female genital cytodifferentiation. In males, however, it seems that Doublesex(M) is not continuously required during larval development for blocking the Wingless signaling pathway in the female genital primordium. Furthermore, Doublesex(M) does not appear to be needed during pupation for male genital cytodifferentiation. Using dachshund as a gene target for Decapentaplegic and Wingless signals, it was also found that Doublesex(M) and Doublesex(F) both positively and negatively control the response to these signals in male and female genitalia, respectively. A model is presented for the dimorphic sexual development of the genital primordium in which both Doublesex(M) and Doublesex(F) products play positive and negative roles.

Effect of initial glucose concentration and inoculation level of lactic acid bacteria in shrimp waste ensilation

Fermentation conditions and microorganisms were determined, based on acid production, glucose concentration as carbohydrate source. Inoculation levels to obtain a stable shrimp waste silage were also determined. Shrimp waste ensilation was an efficient method of preservation, allowing the recovery of chitin and another added-value products such as pigments, proteins and enzymes. From the various lactic acid bacteria tested, Lactobacillus pentosus and Lactobacillus sp. (B2) were the best lactic acid producers, although small quantities of acetic acid were detected in samples inoculated with Lactobacillus pentosus. Therefore B2 was chosen for the analysis of glucose consumption as well as for the determination of optimum inoculation levels. The best results were obtained at 10% (w/w wet basis) and 5% (v/w wet basis) respectively. Presence of starters and initial glucose concentration were critical factors in the fermentation of shrimp waste. High initial glucose and starter concentrations reduced the time and increased the amount of lactic acid produced. The fermentation pattern changed during ensilation from hetero to homofermentative. Shrimp waste ensilation prevented the growth of spoilage microorganisms keeping their microbial counts steady and pH values within the acid region.

A gain-of-function mutant of patched dissects different responses to the hedgehog gradient

The Hedgehog (Hh) signal has an inductive role during Drosophila development. Patched is part of the Hedgehog-receptor complex and shows a repressive function on the signaling cascade, which is alleviated in the presence of Hh. Herein, we identify the first dominant gain-of-function allele of patched, Confused (patched(Con)). Analysis of the patched(Con) allele led us to uncover novel features of the reception and function of the Hh signal. At least three different regions of gene expression were identified and a gradient of cell affinities was established in response to Hh. A new state of Cubitus interruptus activity responsible for the activation of araucan and caupolican genes of the iroquois complex, independent of Fused kinase function, was shown. In the disc, patched(Con) behaved like fused mutants and was rescued by Suppressor of fused mutations. However, fused mutants are embryonic lethal while patched(Con) is not, suggesting that Patched could interpret Hedgehog signaling differently in the embryo and in the adult.

Drosophila terminalia as an appendage-like structure

In Drosophila, the homeotic gene Distal-less (Dll) has a fundamental role in the establishment of the identity of ventral appendages such as the leg and antenna. This study reports the expression pattern of Dll in the genital disc, the requirement of Dll activity for the development of the terminalia and the activation of Dll by the combined action of the morphogenetic signals Wingless (Wg) and Decapentaplegic (Dpp). During the development of the two components of the anal primordium - the hindgut and the analia - only the latter is dependent on Dll and hedgehog (hh) functions. The hindgut is defined by the expression of the homeobox gene even-skipped. The lack of Dll function in the anal primordia transforms the anal tissue into hindgut by the extension of the eve domain. Meanwhile targeted ectopic Dll represses eve expression and hindgut formation. The Dll requirement for the development of both anal plates in males and only for the dorsal anal plate in females, provides further evidence for the previously held idea that the analia arise from two primordia. In addition, evaluation was made of the requirement for the optomotor-blind (omb) gene which, as in the leg and antenna, is located downstream to Dpp. These results suggest that the terminalia show similar behaviour to the leg disc or the antennal part of the eye-antennal disc consistent with both the proposed ventral origin of the genital disc and the evolutive consideration of the terminalia as an ancestral appendage.

Histological and immunophenotypic profile of nasal NK/T cell lymphomas from Peru: high prevalence of p53 overexpression

Nasal NK/T-cell lymphoma is a unique form of lymphoma highly associated with Epstein-Barr virus (EBV). These lymphomas are rare in Western populations and much more prevalent in some Asian and Latin American countries. Although there are several sizable studies from Asian countries, the same is not true from South America. The aim of this study was to analyze a series of 32 cases of nasal T-cell lymphoma from Peru and to further extend the characterization of this disease. Immunohistochemistry was performed on paraffin sections using the following antibodies: CD20 (L26), CD45RO, CD3, Ki67, CD57, CD56, TIA-1, bcl-2, and p53. The presence of EBV was investigated with immunohistochemical analysis for latent membrane protein (LMP)-1 and in situ hybridization using an antisense riboprobe to EBER 1. The 32 patients included 18 men and 14 women (M:F ratio, 1.2:1), with a median age of 43 years (11 to 72). Three categories were identified: (1) Nasal NK/T cell lymphomas (28 cases): The morphology ranged from small or medium-sized cells to large transformed cells. Necrosis was present in 86% of the cases, and angioinvasion was seen in 36% of the cases. All cases were positive for CD45RO, CD3, and for TIA-1. CD56 was positive in 21 of 27 cases (78%), and CD57 was negative in all cases. EBER 1 positivity was identified in most of the tumor cells in 27 of 28 cases (96%), including the six cases in which CD56 was negative. Overexpression of p53 was detected in 24 cases (86%). (2) Blastic NK cell lymphoma (1 case): The neoplastic cells resembled those of lymphoblastic lymphoma. CD56 and CD45RO were positive; TIA-1, TdT, and EBER-1 were negative. (3) Peripheral T-cell lymphoma (PTCL) unspecified (3 cases): CD56, TIA-1, and EBER-1 were negative. Nasal lymphomas from Peru with a T cell phenotype are predominantly EBV-associated NK/T cell lymphomas, similar to those described in Asian countries. The expression of CD56, TIA-1, and EBER-1, in combination, are very useful markers for the diagnosis of nasal NK/T cell lymphoma in paraffin-embedded tissue. The differential diagnosis of T-cell lymphomas in the nasal region should include rare cases of PTCL unspecified and the blastic variant of NK cell lymphoma. P53 is overexpressed in 86% of the cases. The significance of this finding with regard to clinical behavior and prognosis remains to be determined.

Epstein-Barr virus in nasal lymphomas contains multiple ongoing mutations in the EBNA-1 gene

We have described 5 major subtypes of Epstein-Barr virus (EBV) based on variations in EBNA-1 sequences. These include P-ala (identical to the prototype B95.8 virus), P-thr, V-pro, V-leu, and V-val. Normal individuals often carry multiple EBV subtypes, the most common being P-ala, whereas EBV-associated tumors examined to date always contain a single subtype, which only on rare occasion is P-ala. The primary hypotheses that these observations generate are as follows: (1) Each of these EBV subtypes are naturally occurring, and in normal individuals the multiplicity of subtypes results from multiple infections. (2) EBV subtypes in normal individuals are generated in vivo from a single infecting virus subtype by mutations in EBNA-1. The second hypothesis essentially excludes the possibilities that the nonrandom association of certain subtypes with lymphomas is secondary to the geographic distribution of EBV subtypes and, if proven correct, could provide strong support for a direct role of EBV in tumorigenesis. In this report, we provide evidence for the latter hypothesis. We show that the P-ala EBV subtype present in most nasal lymphomas undergoes and accumulates multiple mutations consistent with the generation of variant species of EBNA-1 in vivo. This phenomenon is similar to the generation of quasispecies in RNA viruses and is the first description of in vivo generation of subtypes in DNA viruses. In RNA-based viruses, including human immunodeficiency virus and hepatitis C virus, the emergence of quasispecies is linked to replication infidelity and significantly influences disease processes through its effect on viral tropism, the emergence of viruses resistant to the host defenses or to therapy, and pathogenicity. The present data thus raise important questions relating to the mechanisms whereby these mutations are generated in EBV and their relevance to the pathogenicity of EBV-associated lymphomas.

The homeobox gene Distal-less induces ventral appendage development in Drosophila

This study investigates the role of the homeobox gene Distal-less (Dll) in the development of the legs, antennae, and wings of Drosophila. Lack of Dll function causes a change in the identity of ventral appendage cells (legs and antennae) that often results in the loss of the appendage. Ectopic Dll expression in the proximal region of ventral appendages induces nonautonomous duplication of legs and antennae by the activation of wingless and decapentaplegic. Ectopic Dll expression in dorsal appendages produces transformation into corresponding ventral appendages; wings and halteres develop ectopic legs and the head-eye region develops ectopic antennae. In the wing, the exogenous Dll product induces this transformation by activating the endogenous Dll gene and repressing the wing determinant gene vestigial. It is proposed that Dll induces the development of ventral appendages and also participates in a genetic address that specifies the identity of ventral appendages and discriminates the dorsal versus the ventral appendages in the adult. However, unlike other homeotic genes, Dll expression and function is not defined by a cell lineage border. Dll also performs a secondary and late function required for the normal patterning of the wing.

Hedgehog activity, independent of decapentaplegic, participates in wing disc patterning

In the Drosophila wing imaginal disc, the Hedgehog (Hh) signal molecule induces the expression of decapentaplegic (dpp) in a band of cells abutting the anteroposterior (A/P) compartment border. It has been proposed that Dpp organizes the patterning of the entire wing disc. We have tested this proposal by studying the response to distinct levels of ectopic expression of Hh and Dpp, using the sensory organ precursors (SOPs) of the wing and notum and the presumptive wing veins as positional markers. Here, we show that Dpp specifies the position of most SOPs in the notum and of some of them in the wing. Close to the A/P compartment border, however, SOPs are specified by Hh rather than by Dpp alone. We also show that late signaling by Hh, after setting up dpp expression, is responsible for the formation of vein 3 and the scutellar region, and also for the determination of the distance between veins 3 and 4. One of the genes that mediates the Hh signal is the zinc-finger protein Cubitus interruptus (Ci). These results indicate that Hh has a Dpp-independent morphogenetic effect in the region of the wing disc near the A/P border.

The fu gene discriminates between pathways to control dpp expression in Drosophila imaginal discs

The genes decapentaplegic (dpp) and wingless (wg), which encode secreted factors of the TGF-beta and Wnt families, respectively, are required for the proper development of the imaginal discs. The expression of these genes must be finely regulated since their ectopic expression induces overgrowth and pattern alterations in wings and legs. Genes like patched (ptc) and costal-2 (cos-2), and the gene encoding the catalytic subunit of the protein kinase A gene (pkA) are required to restrict dpp and wg expression in their proper positions. We show here that some mutations in the cubitus interruptus (ci) gene also show ectopic dpp expression in the wing disc. We have also analyzed the functional hierarchy between these genes and the gene fused (fu), in the activation of dpp by the hedgehog (hh) signal. fu is required to transmit the hh signal in imaginal discs, since fu mutations rescue the phenotype due to the ectopic hh expression or to the lack of ptc activity. fu is also required for the activation of engrailed (en) caused when hh is ectopically activated in the wing disc. By contrast, fu mutations do not rescue the phenotypic consequences of the abnormal ci, cos-2 or pkA activity. Although fu, cos-2 and ci probably form part of the same pathway that controls dpp expression, pkA probably controls dpp transcription by a different pathway.

The function of engrailed and the specification of Drosophila wing pattern

The adult Drosophila wing (as the other appendages) is subdivided into anterior and posterior compartments that exhibit characteristic patterns. The engrailed (en) gene has been proposed to be paramount in the specification of the posterior compartment identity. Here, we explore the adult en function by targeting its expression in different regions of the wing disc. In the anterior compartment, ectopic en expression gives rise to the substitution of anterior structures by posterior ones, thus demonstrating its role in specification of posterior patterns. The en-expressing cells in the anterior compartment also induce high levels of the hedgehog (hh) and decapentaplegic (dpp) gene products, which results in local duplications of anterior patterns. Besides, hh is able to activate en and the engrailed-related gene invected (inv) in this compartment. In the posterior compartment we find that elevated levels of en product result in partial inactivation of the endogenous en and inv genes, indicating the existence of a negative autoregulatory mechanism. We propose that en has a dual role: a general one for patterning of the appendage, achieved through the activation of secreted proteins like hh and dpp, and a more specific one, determining posterior identity, in which the inv gene may be implicated.

Targeted expression of the signaling molecule decapentaplegic induces pattern duplications and growth alterations in Drosophila wings

In the wing imaginal disc, the decapentaplegic (dpp) gene is expressed in a stripe of anterior cells near the anterior-posterior compartment boundary, and it is required solely in these cells for the entire disc to develop. In some viable segment polarity mutants, alterations in dpp expression have been demonstrated that correlate with changes in wing morphology. To test the hypothesis that the abnormal patterns of dpp expression are responsible directly for the mutant phenotypes, we have expressed dpp in ectopic places in wing imaginal discs, and we have found that dpp is able to cause overgrowth and pattern duplications in both anterior and posterior compartments of the wing disc. The alterations of the anterior compartment are strikingly similar to those observed in some viable segment polarity mutants. Thus, ectopic dpp alone can account for the phenotype of these mutants. We also show that ectopic expression of the segment polarity gene hedgehog (hh) gives similar morphological changes and activates dpp expression in the anterior compartment. This strongly suggests that the organizating activity of hh is mediated by dpp. We propose that the expression of dpp near the anterior-posterior compartment boundary is directed by the interaction between patched and hh, and that dpp itself could act as a general organizer of the patterning in the wing imaginal disc.

Developmental consequences of unrestricted expression of the abd-A gene of Drosophila

The abdominal-A (abd-A) gene of Drosophila specifies abdominal segments two through eight (A2-A8). We have found that the uniform expression of the abd-A protein under heat shock control transforms embryonic segments anterior to the abd-A domain into an abdominal segment of the A2-A6 type. Posterior abdominal segments and telson undergo little or no transformation, that is, the abd-A product is phenotypically suppressed posterior to its realm of expression. The comparison of wildtype embryos with embryos carrying the heat shock-abd-A construct but no abd-A endogenous product indicate that some elements of the pattern-like shape of denticle belts or ventral pits depend on the amount of abd-A protein. The concurrent expression of abd-A and other homeotic genes suggest competition for common downstream genes. This competition has been studied by looking at the expression on the visceral mesoderm of a gene downstream of abd-A, decapentaplegic, when two homeoproteins with opposing effects on its transcription are simultaneously induced.

Subcellular localization of the segment polarity protein patched suggests an interaction with the wingless reception complex in Drosophila embryos

The product of the segment polarity gene patched is a transmembrane protein involved in the cell communication processes that establish polarity within the embryonic segments of Drosophila. Monoclonal antibodies have been raised against the patched protein, and by immunoelectron microscopy part of the patched staining is found associated with discrete regions of the lateral plasma membrane of the embryonic epidermal cells. Using a mutation affecting endocytosis (shibire) we find that patched is a membrane-bound protein, which is internalized by endocytosis, and that the preferential sites of accumulation resemble the described localization of the cell-cell adhesive junctions of the epidermal cells. patched partially co-localizes with the wingless protein in the wingless-expressing and nearby cells, in structures that seem to be endocytic vesicles. These data suggest the interaction of patched protein with elements of the reception complex of wingless, as a way to control the wingless expression.

The Drosophila segment polarity gene patched interacts with decapentaplegic in wing development

The decapentaplegic (dpp) gene of Drosophila melanogaster encodes a polypeptide of the transforming growth factor-beta family of secreted factors. It is required for the proper development of both embryonic and adult structures, and may act as a morphogen in the embryo. In wing imaginal discs, dpp is expressed and required in a stripe of cells near the anterior-posterior compartment boundary. Here we show that viable mutations in the segment polarity genes patched (ptc) and costal-2 (cos2) cause specific alterations in dpp expression within the anterior compartment of the wing imaginal disc. The interaction between ptc and dpp is particularly interesting; both genes are expressed with similar patterns at the anterior-posterior compartment boundary of the disc, and mis-expressed in a similar way in segment polarity mutant backgrounds like ptc and cos2. This mis-expression of dpp could be correlated with some of the features of the adult mutant phenotypes. We propose that ptc controls dpp expression in the imaginal discs, and that the restricted expression of dpp near the anterior-posterior compartment boundary is essential to maintain the wild-type morphology of the wing disc.

Unrestricted expression of the Drosophila gene patched allows a normal segment polarity

In the Drosophila embryo, mutations in the segment polarity gene patched (ptc) cause the replacement of the middle region of each segment by a mirror-image duplication of the remaining structures, including the parasegmental border. This gene, which encodes a transmembrane protein, is initially expressed in a generalized way at blastoderm, but later stops being transcribed in cells expressing the engrailed gene, and even later in cells in the middle of the parasegment. The genes engrailed (en) and wingless (wg) are also segment-polarity genes, and they are expressed in adjacent stripes flanking the parasegment borders in the embryo; in ptc mutants wg expression extends anteriorly and an ectopic stripe of en expression is induced. The suggestion has been made that ptc must be transcribed in a specific subset of cells to prevent en expression anterior to the wg-expressing stripe. Here we report that unrestricted expression of ptc from a heat-shock promoter has no adverse effect on development of Drosophila embryos. The heat-shock construct can also rescue ptc mutants, restoring wg expression to its normal narrow stripe. The ectopic en stripe fails to appear, but the normal one remains unaffected. The results imply that, despite its localized requirement, the restricted expression of ptc does not itself allocate positional information.

A protein with several possible membrane-spanning domains encoded by the Drosophila segment polarity gene patched

The patterning of cells in insect segments requires the exchange of information between cells, which in Drosophila depends on the activity of members of the segment-polarity class of genes. Here we report the molecular characterization of one such gene, patched. We find that patched encodes a large protein with several possible membrane-spanning domains and is expressed in a complex pattern during embryogenesis.

Concomitant K- and N-ras gene point mutations in clonal murine lymphoma

We have surveyed a panel of induced murine lymphomas for c-ras gene mutations. The K-ras gene seems to be preferentially activated in our system, and there are at least two examples of concomitant K- and N-ras gene mutations in the same tumor. This indicates that in some cases additional ras mutations may contribute to tumorigenesis and is evidence for a role of ras activation in tumor progression.

Dissociation of c-fos from ODC expression and neuronal differentiation in a PC12 subline stably transfected with an inducible N-ras oncogene

In order to develop a model system for investigating the role of ras genes in neuronal differentiation, a construct consisting of a mouse N-ras oncogene linked to a dexamethasone-inducible promoter was devised and transfected into a subline of the PC12 rat pheochromocytoma cell line. Clonal lines were isolated which extended neurite-like processes within one day of exposure to dexamethasone. N-ras had a strong antiproliferative effect on these cells. These effects were reversible after removing dexamethasone. Elevation of mRNA for ornithine decarboxylase (ODC) was detected 6-18 hours after induction of N-ras by dexamethasone. The effects of ras on cell division, differentiation and cell size were analogous, but not identical to the effects of NGF on PC12 cells. One NGF action, induction of c-fos mRNA did not occur in ras-induced cells indicating that c-fos induction is unnecessary for both neurite outgrowth and for subsequent induction of ODC mRNA. The ability of ras to induce ODC, a division promoting enzyme, may also be relevant to the transforming actions of ras oncogenes.

Mouse N-ras genes: organization of the functional locus and of a truncated cDNA-like pseudogene

The N-ras gene was first identified in both humans and mice as a mutationally activated oncogene found in tumors. The nucleotide sequence and intron/exon structure of the coding region of the mouse gene have been determined previously. We have now determined the sequence and intron/exon structure of the 5' and 3' untranslated regions of mouse N-ras. Like its human homolog, the 3' untranslated region of the gene is encoded by two exons, and the 5' region is encoded by one. In addition, we have isolated and sequenced a second mouse gene homologous to N-ras. This locus, which we have named N-ras-2ps, resides at a chromosomal site distinct from N-ras and appears to be a truncated cDNA-like pseudogene.

Differential expression of the ras gene family in mice

We compared the expression of the ras gene family (H-ras, K-ras, and N-ras) in adult mouse tissues and during development. We found substantial variations in expression among different organs and in the amounts of the different transcripts originating from each gene, especially for the N-ras gene. The expression patterns were consistent with the reported preferential tissue activation of ras genes and suggested different cellular functions for each of the ras genes.

Activated N-ras gene induces neuronal differentiation of PC12 rat pheochromocytoma cells

Activated mouse N-ras gene transfected into PC12 rat pheochromocytoma cells suppressed proliferation and promoted neuronal differentiation. Normal mouse N-ras in a LTR-containing vector caused differentiation with a reduced efficiency, but normal N-ras in a vector lacking LTR sequences failed to alter the PC12 phenotype. Cultures of NGF-resistant PC12 variant subline U7 also showed outgrowth of neurites and cessation of cell division following transfection with the mutated ras gene. The present findings suggest that ras genes can, in certain cells, play a role in promoting differentiation and suppressing proliferation, in contrast to their established oncogenic neoplasia-promoting activity in other cells.