Genetic regulation of the development of mating projections in Candida albicans

Candida albicans is a major human fungal pathogen, capable of switching among a range of morphological types, such as the yeast form, including white and opaque cell types and the GUT (gastrointestinally induced transition) cell type, the filamentous form, including hyphal and pseudohyphal cell types, and chlamydospores. This ability is associated with its commensal and pathogenic life styles. In response to pheromone, C. albicans cells are able to form long mating projections resembling filaments. This filamentous morphology is required for efficient sexual mating. In the current study, we report the genetic regulatory mechanisms controlling the development of mating projections in C. albicans. Ectopic expression of MTLα1 in “a” cells induces the secretion of α-pheromone and promotes the development of mating projections. Using this inducible system, we reveal that members of the pheromone-sensing pathway (including the pheromone receptor), the Ste11-Hst7-Cek1/2 mediated MAPK signalling cascade, and the RAM pathway are essential for the development of mating projections. However, the cAMP/PKA signalling pathway and a number of key regulators of filamentous growth such as Hgc1, Efg1, Flo8, Tec1, Ume6, and Rfg1 are not required for mating projection formation. Therefore, despite the phenotypic similarities between filaments and mating projections in C. albicans, distinct mechanisms are involved in the regulation of these two morphologies.

Splenomegaly during oxaliplatin-based chemotherapy in colon cancer

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Background: Splenic enlargement has been reported in patients treated with oxaliplatin. However, the characteristics of oxaliplatin-induced splenomegaly were not well studied. Here we evaluated the change of splenic volume and its clinical significance in patients treated by oxaliplatin-based regimen. Methods: Patients with stage II-IV primary colon cancer treated with oxaliplatin and capecitabine in China National Cancer Center from January 2016 to December 2017 were screened for this retrospective study. Those with complete laboratory tests and computed tomographic data before, during and up to 1.5 years after the chemotherapy were selected. The splenic size was measured by AWVolumeshare5. Splenomegaly was defined as an over 30% increase of splenic size from baseline. Recovery of splenomegaly was defined as the splenic size fell back to a 0.9 to1.1-fold range of baseline. Results: Out of a total of 144 patients, 102 (70.8%) had over 30% increase, 72 (50.0%) had over 50% increase, and 22 (15.3%) had over 100% increase in splenic size after oxaliplatin-based regimen. Among the 102 splenomegaly patients, 5 (4.9%) develop splenomegaly within 3 chemotherapy cycles, 53 (53.0%) within 6 cycles, 73 (71.6%) within 9 cycles, and 102 (100.0%) within 3 months after the last administration of oxaliplatin. Compared to the group without splenomegaly, patients with splenomegaly received more cycles of oxaliplatin administrations (median 8 vs 6, p < 0.001) and greater dose intensity (total dose per square meter) (median 822.8mg/m2 vs 629.3mg/m2, p < 0.001). Patients with splenomegaly had higher incidence of thrombocytopenia (61.7% vs 38.1%, p = 0.009) and are more likely to undergo oxaliplatin dose reduction due to thrombocytopenia (21.6% vs 7.1%, p = 0.038). The recovery rates of splenic size within 0.5, 1 and 1.5 years after the end of oxaliplatin treatment were 23.2%, 50.6% and 74.3%, respectively. Conclusions: Splenomegaly are common in patients treated with oxaliplatin-based chemotherapy, and most would recover in 1.5 years after completion of therapy. Patients with splenomegaly are prone to experience thrombocytopenia and oxaliplatin dose reduction. Further studies are needed to reveal the mechanism how oxaliplatin induce splenomegaly.

Multifunctional phototheranostic nanomedicine for cancer imaging and treatment

Cancer, as one of the most life-threatening diseases, shows a high fatality rate around the world. When improving the therapeutic efficacy of conventional cancer treatments, researchers also conduct extensive studies into alternative therapeutic approaches, which are safe, valid, and economical. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are tumor-ablative and function-reserving oncologic interventions, showing strong potential in clinical cancer treatment. During phototherapies, the non-toxic phototherapeutic agents can be activated upon light irradiation to induce cell death without causing much damage to normal tissues. Besides, with the rapid development of nanotechnology in the past decades, phototheranostic nanomedicine also has attracted tremendous interests aiming to continuously refine their performance. Herein, we reviewed the recent progress of phototheranostic nanomedicine for improved cancer therapy. After a brief introduction of the therapeutic principles and related phototherapeutic agents for PDT and PTT, the existing works on developing of phototheranostic nanomedicine by mainly focusing on their categories and applications, particularly on phototherapy-synergized cancer immunotherapy, are comprehensively reviewed. More importantly, a brief conclusion and future challenges of phototheranostic nanomedicine from our point of view are delivered in the last part of this article.

[Medical viewpoints of Foshuo Wenshi Xiyu Zhongseng Jing]

Foshuo Wenshi Xiyu Zhongseng Jing (, Sutra on Bathing the Sangha in the Bathhouse) as an early Scripture of Han Buddhism, introduced the concept, methods and medical & health care function of bathhouse bathing in detail.The most prominent feature of it, was its distinct medical viewpoints. The medical thoughts were closely related to famous ancient Indian physician Jīvaka and Buddhism's thoughts "Mahābhūta(■, great element)" and "Nidāna (■, cause, motivation or occasion)" .It focused on the good concept of personal life, physical and mental health, objectively benefited human health.Even from the viewpoints of modern medicine, it is also very reasonable.In particular, its noble medical ethics and benevolence, is instructive for the return of humanistic spirit in the medical profession today.

Revision of the medically relevant species of the yeast genus Diutina

Diutina (Candida) rugosa is emerging as a causative agent of human infections. Recently some close relatives have been described, that is, D. mesorugosa, D. pseudorugosa, and D. neorugosa, some of which have also been implicated in human infection. Phylogenetic relationships of 24 clinical isolates of the D. rugosa complex are reconstructed using multilocus sequence analysis of five housekeeping genes, supplemented with phenotypic studies of CandiSelect™ 4 Agar and nutritional physiology. Diutina mesorugosa could not meaningfully be distinguished from D. rugosa and is regarded as a synonym. Diutina neorugosa and D. pseudorugosa represent separate, distantly related species within the genus Diutina, but have as yet not been encountered in clinical settings.

[Application value of dual channel dual curved endoscope in the endoscopic submucosal dissection for gastric angle mucosal lesions]

Objective: To evaluate the clinical value of dual channel dual curved endoscope in the endoscopic submucosal dissection (ESD) for gastric angle mucosal lesions. Methods: A descriptive cohort study was carried out. Clinicopathological data of 20 cases with gastric angle mucosal lesions undergoing ESD by dual channel dual curved endoscope in our center from October 2016 to August 2018 were collected and analyzed retrospectively. Inclusion criteria: (1) the lesion was located in the gastric angle confirmed by gastroscopy before ESD. (2) CT examination showed no distant metastasis. (3) pathological biopsy confirmed precancerous lesion or early cancerous lesion without submucosal invasion. (4) the whole operation was performed by the same endoscopist with ESD experience of about 2000 cases. Patients with previous ESD history of gastric angle and other serious diseases were excluded. The dual channel dual curved endoscopy (Olympus, GIF-2TQ260M) and other conventional endoscopic surgical instruments were used in all the cases. Complete tumor resection rate, pathological results, intraoperative and postoperative complications, operation time and hospitalization time were observed. Follow - up parameters included residual tumor, local recurrence and heterogeneous lesion. Results: Of 20 patients, 14 were male and 6 were female with an average of 55.6 years (range, 37 to 75). All the tumors located in gastric angle. Specimen size ranged from 1.2 to 5.5 (average 2.9) cm. Operation time ranged from 50 to 120 (average 85.8) minutes. Hospital stay ranged from 3 to 7 (average 5.1) days. The en bloc excision was performed successfully in all 20 cases. There was no perforation or bleeding during or after operation. Pathological results showed curative or nearly curative resection stage in all the cases. No tumor residual or recurrence was found during follow-up for 8 to 30 (average 18.5) months. Conclusion: Dual channel dual curved endoscope can provide good vision and easy control in removing the lesion completely and avoiding complications during the ESD procedure in gastric angle mucosal lesions with good long-term efficacy.

The general transcriptional repressor Tup1 governs filamentous development in Candida tropicalis

Filamentous development is associated with the ability to cause infections and colonize the host in pathogenic Candida species. Candida tropicalis is one of the major fungal pathogens of humans. The conserved transcriptional repressor Tup1 plays a critical role in the regulation of transcription and filamentation in yeast species. Despite its central role, the full coding sequence of TUP1 has not been found in the reported genome sequence of C. tropicalis to date. In this study, we report the identification of Tup1 and characterize its role in filamentous growth in C. tropicalis. As expected, C. tropicalis Tup1 exhibits general conserved features to the orthologs of other fungi in terms of its structure and function. Deletion of TUP1 in C. tropicalis leads to increased filamentation under several culture conditions. However, Tup1 indeed exhibits species-specific roles in the regulation of filamentous development in C. tropicalis. For example, unlike the tup1/tup1 mutant of Candida albicans, the tup1/tup1 mutant of C. tropicalis is able to exist in the yeast form at low temperatures or in the presence of N-acetylglucosamine (GlcNAc). Acidic pH conditions also favor the yeast form of the tup1/tup1 mutant of C. tropicalis. Quantitative real-time PCR (qRT-PCR) assays indicate that Tup1 may regulate filamentous development through the transcriptional control of key filamentation regulators in C. tropicalis, such as Ume6, Brg1, Wor1, Sfl2, Ahr1, and Zcf3. Taken together, our findings demonstrate both conserved and species-specific roles of Tup1 in the regulation of filamentation and provide novel insights into the biology of C. tropicalis.

Systematic review of randomized controlled trials on antibiotic treatment for osteomyelitis in diabetes

AIM

To evaluate the efficacy of antibiotic therapy in osteomyelitis treatment among people with diabetes.

METHODS

A systematic search of PubMed, EMBASE, AMED, Web of Science, the WHO trial registry, Cochrane library databases, and ClinicalTrials.gov, in addition to hand-searching, was undertaken in July 2018. Two reviewers independently extracted data. The studies' methodological quality was assessed using the modified Jadad scale. Descriptive analysis was performed.

RESULTS

Seven randomized controlled trials, with 393 participants in total, were included. The antibiotic regimens, treatments and follow-up durations varied among the trials. The total scores showed that the overall methodological quality of the seven studies was high, despite two studies showing some flaws in double-blinding and withdrawals/drop-outs. Of four studies comparing different antibiotic regimens, three implied a similar remission effect, while one implied that ertapenem ± vancomycin treatment showed a higher remission rate than tigecycline treatment; this conclusion was not robust because of low power and small sample size. In the other three studies, which included two different doses of ciprofloxacin, an antibiotics group and a conservative surgical group, and two durations of the same antibiotic strategy, no significant differences in remission were reported between the groups. No difference was observed in the analyses of microbiological outcomes, superinfections and relapse, except adverse events.

CONCLUSIONS

There is no definitive evidence supporting the superiority of any particular antibiotic agent, dose, or administration duration in the treatment of osteomyelitis in diabetes. As the included studies had some flaws and limitations, further research is necessary.

No Difference in Prevalence of Transmitted Drug Resistance between Injection Drug Users and Non-Injection Drug Users: A Cross-Sectional Study among Antiretroviral Treatment-Naïve HIV Patients

OBJECTIVES

The epidemiological evidence is inconsistent about whether HIV-positive injection drug users (IDUs) are at higher risk of developing antiretroviral resistance than any other HIV-positive populations. This study aims to investigate and compare transmitted drug resistance (TDR) between IDUs and non-IDUs in Lingshan County, an HIV-hit region in Guangxi, China, where IDU and heterosexual transmission were the two dominant transmission routes and roughly equally contributed to the local HIV transmission.

METHODS

A cross-sectional study was conducted among newly diagnosed and antiretroviral-treatment (ART)-naïve HIV-1 patients from Lingshan County. The pol gene of HIV-1 from the individuals was sequenced followed by genotyping and TDR analysis.

RESULTS

Two dominant transmission routes, heterosexual contact and IDU, accounted for 49.2 and 45.9% of 183 HIV-1 infection cases, respectively. Three genotypes, including CRF08_BC (70.6%), CRF01_AE (24.4%), and CRF07_BC (5.0%), and three unique recombinant forms (1.6%), were identified. There was a significant difference in genotype distribution among the different transmission routes (F = 21.814, p < 0.001). The overall TDR prevalence was 5.5%. There were no significant differences in TDR prevalence among the different transmission routes (F = 1.420, p = 0.439).

CONCLUSIONS

Injection drug use has little impact on TDR prevalence compared with other routes of transmission.

Environment-induced same-sex mating in the yeast Candida albicans through the Hsf1-Hsp90 pathway

While sexual reproduction is pervasive in eukaryotic cells, the strategies employed by fungal species to achieve and complete sexual cycles is highly diverse and complex. Many fungi, including Saccharomyces cerevisiae and Schizosaccharomyces pombe, are homothallic (able to mate with their own mitotic descendants) because of homothallic switching (HO) endonuclease-mediated mating-type switching. Under laboratory conditions, the human fungal pathogen Candida albicans can undergo both heterothallic and homothallic (opposite- and same-sex) mating. However, both mating modes require the presence of cells with two opposite mating types (MTLa/a and α/α) in close proximity. Given the predominant clonal feature of this yeast in the human host, both opposite- and same-sex mating would be rare in nature. In this study, we report that glucose starvation and oxidative stress, common environmental stresses encountered by the pathogen, induce the development of mating projections and efficiently permit same-sex mating in C. albicans with an "a" mating type (MTLa/a). This induction bypasses the requirement for the presence of cells with an opposite mating type and allows efficient sexual mating between cells derived from a single progenitor. Glucose starvation causes an increase in intracellular oxidative species, overwhelming the Heat Shock transcription Factor 1 (Hsf1)- and Heat shock protein (Hsp)90-mediated stress-response pathway. We further demonstrate that Candida TransActivating protein 4 (Cta4) and Cell Wall Transcription factor 1 (Cwt1), downstream effectors of the Hsf1-Hsp90 pathway, regulate same-sex mating in C. albicans through the transcriptional control of the master regulator of a-type mating, MTLa2, and the pheromone precursor-encoding gene Mating α factor precursor (MFα). Our results suggest that mating could occur much more frequently in nature than was originally appreciated and that same-sex mating could be an important mode of sexual reproduction in C. albicans.

Compact laser system for a laser-cooled ytterbium ion microwave frequency standard

The development of a transportable microwave frequency standard based on the ground-state transition of ¹⁷¹Yb⁺ at ∼12.6 GHz requires a compact laser system for cooling the ions, clearing out of long-lived states and also for photoionisation. In this paper, we describe the development of a suitable compact laser system based on a 6U height rack-mounted arrangement with overall dimensions 260 × 194 × 335 mm. Laser outputs at 369 nm (for cooling), 399 nm (photoionisation), 935 nm (repumping), and 760 nm (state clearout) are combined in a fiber arrangement for delivery to our linear ion trap and we demonstrate this system by cooling of ¹⁷¹Yb⁺ ions. Additionally, we demonstrate that the lasers at 935 nm and 760 nm are close in frequency to water vapor and oxygen absorption lines, respectively; specifically, at 760 nm, we show that one ¹⁷¹Yb⁺ transition is within the pressure broadened profile of an oxygen line. These molecular transitions form convenient wavelength references for the stabilization of lasers for a ¹⁷¹Yb⁺ frequency standard.

Vapour Pressure above the Glassy Trehalose Solution and Glass Relaxation

BACKGROUND

Data are scarce on thermophysical properties of the glassy trehalose solution at low temperatures.

OBJECTIVE

Water vapor pressure above the glassy trehalose solution and the relaxation behavior were studied at temperatures from -57°C to -40°C and at concentrations from 71% to 78% (w/w).

MATERIALS AND METHODS

Glassy trehalose solutions were prepared by quenching in liquid nitrogen. Vapour pressure was measured using the static method.

RESULTS

Vapour pressure above the glassy trehalose solution was slightly lower than above the glassy sucrose solution. The relaxation of the glassy state can be described by the stretched exponential Kohlrausch-Williams-Watts (KWW) function. The characteristic times of water relaxation (Τ_p) were compared with those of enthalpy relaxation (Τ_e). When the difference (∆T) between the glass transition temperature (T_g) and ageing temperature was relatively small, i.e. ∆T ≤ 10 K, Τ_p is close to Τ_e. If ∆T ≥ 15 K, Τ_e will be much greater than Τ_p.

CONCLUSION

The difference of water vapor pressure above the trehalose glassy solution and sucrose glassy solution could lead to significant distinction between their drying kinetics.

Is lower low-density lipoprotein cholesterol associated with lower androgen and erectile dysfunction in men?

BACKGROUND AND AIMS

Therapeutic possibilities now exist to lower low-density lipoprotein cholesterol (LDL-C) to very low levels. However, substantial controversy remains in clinical practice with regard to its safety, and the question of whether low LDL-C levels per se may provoke adverse effects in humans arises. We aimed to explore the association of LDL-C with androgen and erectile dysfunction (ED) in a general population of men.

METHODS AND RESULTS

A total of 4203 men without hormone replacement therapy were enrolled from 22 sites in East China. Total testosterone (T) and Free T were assessed. Free androgen index (FAI) was calculated. The IIEF-5 questionnaire was used to assess ED. We found that free T and FAI gradually and markedly increased with increasing LDL-C levels. Using linear regression, after adjusting for age, educational level, economic status, smoking status, drinking status, BMI, diabetes, and use of lipid-lowering medication, LDL-C was positively associated with free T (B = 0.175, 95% CI: 0.084, 0.266) and FAI (B = 0.064, 95% CI: 0.016, 0.112). Meanwhile, there was a U-shaped curvilinear relationship between LDL-C and prevalence of ED. In the logistic regression analysis, compared to those with LDL-C among the 10th-90th percentile, the ORs of ED in men in the lowest and highest deciles were 1.938 (95% CI: 1.121, 3.349) and 1.804 (95% CI: 1.117, 2.916), respectively.

CONCLUSION

Lower LDL-C levels were significantly associated with lower free T and lower FAI in a general population of men. Moreover, both low and high levels of LDL-C might be risk factors for ED.

Multiple roles and diverse regulation of the Ras/cAMP/protein kinase A pathway in Candida albicans

Candida albicans is a major fungal pathogen of humans, causing both superficial and life-threatening systemic infections in immunocompromised people. The conserved Ras/cAMP/PKA pathway plays a key role in regulating multiple traits important for the virulence of C. albicans such as cell growth, yeast-hyphal transition, white-opaque switching, sexual reproduction and biofilm development. Diverse external signals influence cell physiology by activating this signaling pathway. The key components of the Ras/cAMP/PKA pathway include two Ras GTPases (Ras1 and Ras2), an adenylyl cyclase (Cyr1, also known as Cdc35), two cyclic nucleotide phosphodiesterases (Pde1 and Pde2) and the catalytic (Tpk1 and Tpk2) and regulatory (Bcy1) subunits of PKA kinase. Activation of this pathway dramatically alters the gene expression profile via several transcription factors, leading to the activation of specific biological processes. Here, we review the progress made in the past two decades to elucidate the molecular mechanisms by which the Ras/cAMP/PKA pathway senses diverse environmental cues and controls specific cellular responses and its connection with other signaling pathways in C. albicans.