Alterations of surface morphology caused by the metabolism of menadione in mammalian cells are associated with the oxidation of critical sulfhydryl groups in cytoskeletal proteins

Incubation of freshly-isolated (rat hepatocytes) or cultured (HeLa, GH3, and McCoy) mammalian cells with menadione (2-methyl-1,4-naphthoquinone) resulted in the appearance of numerous cell surface protrusions. The perturbation of surface structure was associated with an increase in the amount of cytoskeletal protein and the oxidation of sulfhydryl groups in actin, leading to the formation of high-molecular weight aggregates sensitive to treatment with thiol reductants. Our findings indicate that the oxidation of thiol groups in cytoskeletal proteins may be responsible for menadione-induced cell surface abnormalities in mammalian cells.

Calcium-dependent DNA fragmentation in human synovial cells exposed to cold shock

Exposure of confluent human synovial McCoy's cells to near-freezing temperatures followed by rewarming at 37 degrees C resulted in endonuclease activation and cell death characteristic of a suicide process known as apoptosis. Both DNA fragmentation and cell killing were dependent on a sustained increase in the cytosolic Ca2+ concentration. Sensitivity to cold shock-induced endonuclease activation was critically dependent on the cell cycle (proliferative) status and limited to confluent cells, whereas cells in the logarithmic growth phase were completely resistant. However, DNA fragmentation was promoted in the proliferating McCoy's cells pretreated with H-7 or sphingosine, inhibitors of protein kinase C. In addition, phorbol ester, known to activate PKC, inhibited DNA fragmentation in the confluent cells. Our findings indicate that cold shock-induced DNA fragmentation in McCoy's cells is dependent on a sustained Ca2+ increase, and sensitivity to the process appears to be regulated by the status of protein kinase C.

Plant transcription factors from the homeodomain-leucine zipper family I. Role in development and stress responses

In front of stressful conditions plants display adaptation mechanisms leading to changes in their morphology, physiology, development and molecular composition. Transcription factors (TFs) play crucial roles in these complex adaptation processes. This work is focused in the homeodomain-leucine zipper I (HD-Zip I) family of TFs, unique to plants. First discovered in 1991, they were identified and isolated from monocotyledonous and dicotyledonous plants showing high structural similarity and diversified functions. These TFs have, besides the homeodomain and leucine zipper, conserved motifs in their carboxy-termini allowing the interaction with the basal machinery and with other regulatory proteins. The model dicotyledonous plant Arabidopsis thaliana has 17 HD-Zip I members; most of them regulated by external stimuli and hormones. These TFs are involved in key developmental processes like root and stem elongation, rosette leaves morphology determination, inflorescence stem branching, flowering and pollen hydration. Moreover, they are key players in responses to environmental stresses and illumination conditions. Several HD-Zip I encoding genes from different species were protected in patents because their overexpression or mutation generates improved agronomical phenotypes. Here we discuss many aspects about these TFs including structural features, biological functions and their utilization as biotechnological tools to improve crops. © 2017 IUBMB Life, 69(5):280-289, 2017.

The underground life of homeodomain-leucine zipper transcription factors

Roots are the anchorage organs of plants, responsible for water and nutrient uptake, exhibiting high plasticity. Root architecture is driven by the interactions of biomolecules, including transcription factors and hormones that are crucial players regulating root plasticity. Multiple transcription factor families are involved in root development; some, such as ARFs and LBDs, have been well characterized, whereas others remain less well investigated. In this review, we synthesize the current knowledge about the involvement of the large family of homeodomain-leucine zipper (HD-Zip) transcription factors in root development. This family is divided into four subfamilies (I-IV), mainly according to structural features, such as additional motifs aside from HD-Zip, as well as their size, gene structure, and expression patterns. We explored and analyzed public databases and the scientific literature regarding HD-Zip transcription factors in Arabidopsis and other species. Most members of the four HD-Zip subfamilies are expressed in specific cell types and several individuals from each group have assigned functions in root development. Notably, a high proportion of the studied proteins are part of intricate regulation pathways involved in primary and lateral root growth and development.

Non-climacteric fruit development and ripening regulation: 'the phytohormones show'

Fruit ripening involves numerous physiological, structural, and metabolic changes that result in the formation of edible fruits. This process is controlled at different molecular levels, with essential roles for phytohormones, transcription factors, and epigenetic modifications. Fleshy fruits are classified as either climacteric or non-climacteric species. Climacteric fruits are characterized by a burst in respiration and ethylene production at the onset of ripening, while regulation of non-climacteric fruit ripening has been commonly attributed to abscisic acid (ABA). However, there is controversy as to whether mechanisms regulating fruit ripening are shared between non-climacteric species, and to what extent other hormones contribute alongside ABA. In this review, we summarize classic and recent studies on the accumulation profile and role of ABA and other important hormones in the regulation of non-climacteric fruit development and ripening, as well as their crosstalk, paying special attention to the two main non-climacteric plant models, strawberry and grape. We highlight both the common and different roles of these regulators in these two crops, and discuss the importance of the transcriptional and environmental regulation of fruit ripening, as well as the need to optimize genetic transformation methodologies to facilitate gene functional analyses.

A case of Cunninghamella bertholettiae rhino-cerebral infection in a leukaemic patient and review of recent published studies

Cunninghamella bertholletiae infection occurs most frequently in neutropenic patients affected by haematological malignancies, is associated with an unfavourable outcome. We report a case of rhino-mastoidal fungal infection in a leukaemic patient. Bioptical tissue cultures yield the isolation of a mould with typical properties of Cunninghamella species. Liposomal amphotericin B (L-Amb) therapy combined with surgical intervention brought the lesion to recovery. Nevertheless, the patient died 14 days after bone marrow transplantation (BMT) from bacterial sepsis. Mastoiditis was documented at CT-scan. The conditioning regimen probably caused the reactivation of the Cunninghamella infection that led to the patient's fatal outcome; fungal hyphae were detected after autopsy of brain and lung tissue.

Lateral root development differs between main and secondary roots and depends on the ecotype

Root architecture depends on the development of the main root and also on the number and density of lateral roots. Most molecular knowledge about the development of lateral roots was acquired studying primary roots, and it was implied that high order roots follow the same pattern. Recently, we informed that AtHB23 is differentially regulated in primary and secondary roots. Here we show that LBD16, a target of AtHB23, also is differentially regulated; it is expressed in the tip of secondary and tertiary roots but not in primary ones. Moreover, the key hormone auxin exhibits a different distribution pattern in secondary and tertiary roots, according to the reporter DR5. Finally, we show that in Col 0 and Ler ecotypes development of secondary and tertiary roots exhibits significant variations. Altogether, we can conclude that different genetic programs govern secondary and tertiary roots development and such processes are dependent on the Arabidopsis genotype.

Body fat mass is a strong and negative predictor of peak stimulated growth hormone and bone mineral density in healthy adolescents during transition period

The adipose tissue has detrimental effects on growth hormone secretion, even in the absence of obesity. The majority of previous studies have shown an inverse relationship between fat mass and the growth hormone response to several stimulation tests in adults and in children. The contribution of body fat mass on growth hormone response to provocative tests during the transition age is not known. We analyzed the GH-IGF1 axis by GHRH-arginine test in 30 healthy adolescents with normal stature during the transition period from 14 to 18 years. All subjects underwent body composition analysis by dual-energy X-ray absorptiometry (DXA). We found that total body fat mass was inversely correlated with peak GH to provocative test (r=-0.6, p=0.004). GH deficiency was shown in 2 of our healthy patients if diagnosis was based on GH peak below 19 μg/l. Both children who failed the GHRH-arginine were overweight (BMI for age above 85th percentile). However, their GH status was normal when assessed by insulin tolerance test. Multivariate analysis demonstrated strong correlation between peak stimulated GH and measures of body adiposity, including body mass index and fat mass index, with the latter showing the most important effect on GH secretion. Fat mass index alone explained 34.5% of the variability in peak GH. This study has shown for the first time that during the transition period, GH response to GHRH-arginine test is strongly influenced by body composition, and cutoff values appropriate for overweight and obese adolescents are needed.

AtHB40 modulates primary root length and gravitropism involving CYCLINB and auxin transporters

Gravitropism is a finely regulated tropistic response based on the plant perception of directional cues. Such perception allows them to direct shoot growth upwards, above ground, and root growth downwards, into the soil, anchoring the plant to acquire water and nutrients. Gravity sensing occurs in specialized cells and depends on auxin distribution, regulated by influx/efflux carriers. Here we report that AtHB40, encoding a transcription factor of the homeodomain-leucine zipper I family, was expressed in the columella and the root tip. Athb40 mutants exhibited longer primary roots. Enhanced primary root elongation was in agreement with a higher number of cells in the transition zone and the induction of CYCLINB transcript levels. Moreover, athb40 mutants and AtHB40 overexpressors displayed enhanced and delayed gravitropistic responses, respectively. These phenotypes were associated with altered auxin distribution and deregulated expression of the auxin transporters LAX2, LAX3, and PIN2. Accordingly, lax2 and lax3 mutants also showed an altered gravitropistic response, and LAX3 was identified as a direct target of AtHB40. Furthermore, AtHB40 is induced by AtHB53 when the latter is upregulated by auxin. Altogether, these results indicate that AtHB40 modulates cell division and auxin distribution in the root tip thus altering primary root length and gravitropism.

Vibrant Soundbridge for hearing restoration after chronic ear surgery

INTRODUCTION

Middle ear surgery is primarily concerned with resolving the discharging pathology, in the case of chronic otitis media (COM), or with complete eradication, in case of cholesteatoma. Either of these procedures may require repeated surgeries, often resulting in severe mixed hearing impairment. A middle ear implant may be indicated in these cases instead of a hearing aid because the anatomical conditions in such cases often impede an adequate acoustic coupling. The objective of this study was to evaluate MED-EL Vibrant Soundbridge (VSB) implantation in patients with severe conductive and mixed hearing loss occurring after middle ear surgery for cholesteatoma or chronic otitis media (COM).

MATERIALS AND METHODS

Over a 2-years period, the VSB system was implanted in 40 patients between 35 and 81 year old (mean: 59.5). Surgery was performed with comparable technique in 3 regional hospitals in Italy: Rovereto (n=16), Meran (n=12) and Tortona (n=12). The 40 candidates for implantation had a history of 1-5 previous surgeries. Of those, 20 patients suffered from COM and 20 from, cholesteatomas. The floating mass transducer (FMT) of the VSB was placed and stabilized on the round window niche in 32 cases; alternative positioning was necessary in 8 cases. Bone conduction (BC) was tested 1 day post-operatively. At 1 month post-surgery and between 6-9 months, open-field warble tones threshold in VSB-off and VSB-on conditions and open-field speech audiometry for words in quiet were conducted.

RESULTS

Results of BC audiometry one day post-operatively showed no significant changes in hearing. Unaided mean pure tone average (PTA4) was 82.38 dB SPL with a mean speech recognition threshold (SRT) of 94.28 dB SPL. Results obtained after a minimum of three months post-operatively were evaluated in terms of aided thresholds and functional gain. At VSB activation, the mean PTA4 was 50.63 dB SPL with a mean SRT of 61.68 dB. After 6-9 months, the group had a mean PTA4 of 47.89 dB SPL and a mean SRT of 53.33 dB SPL.

CONCLUSIONS

Implantation of the VSB with its direct driver of the inner ear fluids appears promising for auditory rehabilitation of severe mixed hearing loss associated with sequelae of cholesteatoma surgery. Patients' results improved over time, allowing us to assume a positive effect of consolidation of the coupling related to fibrosis. Results reported here refer to 6-9 months of observation and do not provide evidence of long term stability.

[Variation, over time, in the pH of the materials used for pulpal-dentinal protection. A new measurement method]

A modern AmpHel pH-meter permits the easy determination of dental materials pH. This new instrument has allowed, analysing seven cements and two varnishes used for pulpodentinal protection, continuously to specify this important parameter's modifications in the long run. The results of this study, conducted for six hours after cement mixing or varnishes application, certified glass ionomer cements' (Ketac-Cem, Fuji-Ionomer II) strong acidity, even higher than well known zinc phosphates' acidity is. A cavity liner's (Tubulitec) pH from an initial value of 6.07 decreased to 5.04 at sixth hour. On the contrary, much lower were the acidity of a modified ZOE (Temrex) and the one of a cavity varnish (Copalite): both showed a physiological pH from the beginning of the test.

Tumor necrosis factor alpha induces apoptosis in mammary adenocarcinoma cells by an increase in intranuclear free Ca2+ concentration and DNA fragmentation

The incubation of human mammary adenocarcinoma cells (BT-20) with tumor necrosis factor alpha in the absence or presence of cycloheximide resulted in progressive DNA fragmentation. This was preceded by a sustained increase in intracellular free Ca2+ concentration and was not detected in cells pretreated with intracellular Ca2+ chelators, calmodulin antagonists, or activators of protein kinase C. Image analysis of fura-2-loaded BT-20 cells treated with tumor necrosis factor alpha revealed that, in many cells, the initial increase in Ca2+ level occurred in a cellular region that corresponded to the localization of the nucleus. Our findings suggest that tumor necrosis factor alpha can promote an increase in intranuclear free Ca2+ which, in turn, may stimulate Ca(2+)-dependent endonuclease activity, resulting in DNA fragmentation and apoptosis.

Two antagonistic gene regulatory networks drive Arabidopsis root hair growth at low temperature linked to a low-nutrient environment

Root hair (RH) cells can elongate to several hundred times their initial size, and are an ideal model system for investigating cell size control. Their development is influenced by both endogenous and external signals, which are combined to form an integrative response. Surprisingly, a low-temperature condition of 10°C causes increased RH growth in Arabidopsis and in several monocots, even when the development of the rest of the plant is halted. Previously, we demonstrated a strong correlation between RH growth response and a significant decrease in nutrient availability in the growth medium under low-temperature conditions. However, the molecular basis responsible for receiving and transmitting signals related to the availability of nutrients in the soil, and their relation to plant development, remain largely unknown. We have discovered two antagonic gene regulatory networks (GRNs) controlling RH early transcriptome responses to low temperature. One GNR enhances RH growth and it is commanded by the transcription factors (TFs) ROOT HAIR DEFECTIVE 6 (RHD6), HAIR DEFECTIVE 6-LIKE 2 and 4 (RSL2-RSL4) and a member of the homeodomain leucine zipper (HD-Zip I) group I 16 (AtHB16). On the other hand, a second GRN was identified as a negative regulator of RH growth at low temperature and it is composed by the trihelix TF GT2-LIKE1 (GTL1) and the associated DF1, a previously unidentified MYB-like TF (AT2G01060) and several members of HD-Zip I group (AtHB3, AtHB13, AtHB20, AtHB23). Functional analysis of both GRNs highlights a complex regulation of RH growth response to low temperature, and more importantly, these discoveries enhance our comprehension of how plants synchronize RH growth in response to variations in temperature at the cellular level.

Humoral immune response against hepatitis C virus

Antibodies are in several instances a reliable marker indicating vigorous immune response against infectious agents and in several viral diseases presence in the blood of specific anti-viral antibodies indicates an effective protection. However, this is not always true. For example, in the case of hepatitis C virus (HCV) an important human pathogen considered the causative agent of the nonA- nonB hepatitis, in spite of an intense antibody response there is no protection against a new infection and in the majority of infected individuals the virus overcomes host defences establishing a persistent infection. Here we describe how the dissection of the humoral immune response against HCV glycoprotein E2 of infected patients was useful for a better comprehension of the virus-host interplay. Cross-reactive antibodies directed against E2 are produced by the HCV-infected patient, but not all of them are protective, and some could even result to be detrimental for the patient. The cross-reactive anti-HCV/E2 humoral antibody response is complex and not necessarily completely beneficial to the host.

[Early ECG changes after experimental focal cerebral ischemia. A pathogenetic hypothesis of the brain-heart syndrome]

Primary CVT alterations and arrhythmias, occurring one hour after embolization were detected in several experiments about focal cerebral ischaemia in rabbits. 62 animals were fed on a standard diet and 15 on an atherogenic diet. Primary CVT alterations and arrhythmias occurred in 4 rabbits fed on a standard diet and in 6 rabbits fed on an atherogenic diet. These results gave statistic evidence of a relationship between more frequent and serious electrocardiographic alterations and an atherogenic diet. The information coming out of these experiments are discussed. Considering the data coming out of other experiments and the data of the literature it is supposed that the pathogenesis of "the cerebro-cardiac syndrome" is linked to several biohumoral alterations occurring after the stroke. If these alterations occur in animals (or in subjects) with damaged coronary arteries cardiac alterations occurring after the stroke are greater and more important than the cardiac alterations occurring in the same conditions in the animals in which coronary arteries are not jet damaged.

[The diagnosis of occupational hand-arm syndromes. 1. The state of the art]

Alterations of the microcirculation are, at our latitudes, the most common distal manifestations of the hand-arm syndrome, and of a number of other work-related diseases. Diagnostic investigations aimed at providing documentary evidence for microvascular damage or disfunction are, therefore, of particular importance. This paper discusses the currently available diagnostic approaches for professional acrosyndromes. The biohumoral alterations associated with cold-induced angiospasm are also described, but their diagnostic utilization is not recommended. The technical aspects of the "cold tests", as well as its advantages and drawbacks, are finally presented. On the basis of a personal experience with over 4.500 subjects, the authors conclude that, in the field of prevention, digital volumetric pulse plethysmography in association with the "cold test" should be adopted to evaluate the worker fitness for specific tasks.

A complex tissue-specific interplay between the Arabidopsis transcription factors AtMYB68, AtHB23, and AtPHL1 modulates primary and lateral root development and adaptation to salinity

Adaptation to different soil conditions is a well-regulated process vital for plant life. AtHB23 is a homeodomain-leucine zipper I transcription factor (TF) that was previously revealed as crucial for plant survival under salinity conditions. We wondered whether this TF has partners to perform this essential function. Therefore, TF cDNA library screening, yeast two-hybrid, bimolecular fluorescence complementation, and coimmunoprecipitation assays were complemented with expression analyses and phenotypic characterization of silenced, mutant, overexpression, and crossed plants in normal and salinity conditions. We revealed that AtHB23, AtPHL1, and AtMYB68 interact with each other, modulating root development and the salinity response. The encoding genes are coexpressed in specific root tissues and at specific developmental stages. In normal conditions, amiR68 silenced plants have fewer initiated roots, the opposite phenotype to that shown by amiR23 plants. AtMYB68 and AtPHL1 play opposite roles in lateral root elongation. Under salinity conditions, AtHB23 plays a crucial positive role in cooperating with AtMYB68, whereas AtPHL1 acts oppositely by obstructing the function of the former, impacting the plant's survival ability. Such interplay supports the complex interaction between these TF in primary and lateral roots. The root adaptation capability is associated with the amyloplast state. We identified new molecular players that through a complex relationship determine Arabidopsis root architecture and survival in salinity conditions.

Phage display for the production of human monoclonal antibodies against human pathogens

In the last decade an increasing number of antibodies have made their way from the research benchtops into the clinics and many more are currently under clinical trial. Among monoclonal antibody-producing techniques, phage-display is undoubtedly the most effective and versatile. Cloning of the entire humoral repertoire derived from an infected patients into a phage display vector allows not only the simple generation of monoclonal antibodies of desired specificity, but also the molecular dissection of the antibody response itself. Generation of large panels of human monoclonal antibodies against human pathogens could open new perspectives in understanding the interplay between the infectious agent and the infected host providing tools for the prevention and the therapy of human communicable diseases. In this paper the basic principles of the phage-display approach as well as its most recent applications are reviewed.

[Echocardiographic assessment of alcohol consumers in different clinical stages]

In relation to the importance of cardiac damage in alcohol drinkers this study aims to check the modifications of some cardiac sonographic parameters in drinkers examined at different stages of alcohol intoxication. Seventy-seven male subjects (43 +/- 9 years old) were divided into 3 groups in relation to the biohumoral alterations used for the diagnosis of chronic alcoholism (increase of GGT and MGV). EF, interventricular septum hypertrophy, LVEdD and the presence of left ventricular diastolic failure were considered. All these cardiac sonographic parameters "in toto" were first compared with the same parameters of a group of normal subjects and then the differences of these sonographic parameters between the 3 groups of drinkers were evaluated. These data confirm the early onset of cardiac damage and also that the cardiac alterations may occur before the modifications of the biohumoral parameters considered too. The alterations of the cardiac sonographic parameters considered in this study seem to be a good marker for the identification, quantification and staging of cardiac damage. Interventricular septum hypertrophy, EF and EDV (in this sequence) are to be considered usefull for the diagnosis of cardiac damage in alcohol drinkers. However also LVEdD and the presence of left ventricular diastolic failure are to be evaluated before any therapy.

Heterogeneity of the humoral anti-HCV/E2 response in persistently infected patients as demonstrated by divergent patterns of inhibition of the binding of anti-HCV/E2 human monoclonal antibodies

A complete understanding of the molecular features of humoral immune response could be of pivotal importance in the management of persistent viruses as HCV. In this study, 24 HCV-positive samples, characterized by classical virological parameters, are evaluated using a new assay for the quantitation of antibody subpopulations directed against discrete epitopes on surface glycoprotein E2, a key viral protein. The results, besides confirming the usefulness of this new approach, highlight the extreme heterogeneity of anti-HCV/E2 response as far as single epitopes are concerned. The specific epitopes under study are also demonstrated to be widely shared among different genotypes.

The brain-heart syndrome: remarks on early ecgraphic changes following focal cerebral ischemia in healthy and in experimentally hyperdyslipidemic rabbits

Early cardiac effects of focal cerebral ischemia in two groups of rabbit, one of which made hyperdyslipidemic with an atherogenic diet, were detected in several experiments. In the group of 62 animals fed on a standard diet, primary CVT alterations and arrhythmias occurred in 4 rabbits (6.4%), in the group of 15 animals fed on an atherogenic diet the same cardiac alterations occurred in 6 rabbits (40%). A marked statistically significant prevalence of ECGraphic changes was observed in hyperdyslipidemic group. These results and the data coming out of other experiments and literature suggest that the pathogenesis of the "cerebro-cardiac syndrome" is linked to several biohumoral alterations occurring after the stroke. If these events affect functionally damaged endothelia, or occur in the presence of atherosclerotic plaques, cardiac alterations occurring after the stroke are greater than cardiac alterations observed in the same condition when coronary are intact or little damaged.

[The diagnosis of occupational hand-arm syndromes. 2. The quantification of the plethysmographic changes due to the cold test]

The diagnostic utility of digital volumetric pulse plethysmography with the cold test in well known for the study of subjects vibrations exposed and symptomatic for acrosyndrome. In this study the authors show how to perform this test and how to analyse the results quantitatively (in particular the time-course of the vascular modifications during cold test) to improve the clinical interpretation and to allow a comparison during the years. The parameters studied are: the morphologic pattern of each wave; the entity, duration and the regression pattern of the modifications after cold test; the existence of hemorrheologic predisposing conditions to vasospasm. To each of these parameters it has attributed a score and all the scores together represent the sphygmic answer to the cold test.