Viruses infecting a warm water picoeukaryote shed light on spatial co-occurrence dynamics of marine viruses and their hosts

The marine picoeukaryote Bathycoccus prasinos has been considered a cosmopolitan alga, although recent studies indicate two ecotypes exist, Clade BI (B. prasinos) and Clade BII. Viruses that infect Bathycoccus Clade BI are known (BpVs), but not that infect BII. We isolated three dsDNA prasinoviruses from the Sargasso Sea against Clade BII isolate RCC716. The BII-Vs do not infect BI, and two (BII-V2 and BII-V3) have larger genomes (~210 kb) than BI-Viruses and BII-V1. BII-Vs share ~90% of their proteins, and between 65% to 83% of their proteins with sequenced BpVs. Phylogenomic reconstructions and PolB analyses establish close-relatedness of BII-V2 and BII-V3, yet BII-V2 has 10-fold higher infectivity and induces greater mortality on host isolate RCC716. BII-V1 is more distant, has a shorter latent period, and infects both available BII isolates, RCC716 and RCC715, while BII-V2 and BII-V3 do not exhibit productive infection of the latter in our experiments. Global metagenome analyses show Clade BI and BII algal relative abundances correlate positively with their respective viruses. The distributions delineate BI/BpVs as occupying lower temperature mesotrophic and coastal systems, whereas BII/BII-Vs occupy warmer temperature, higher salinity ecosystems. Accordingly, with molecular diagnostic support, we name Clade BII Bathycoccus calidus sp. nov. and propose that molecular diversity within this new species likely connects to the differentiated host-virus dynamics observed in our time course experiments. Overall, the tightly linked biogeography of Bathycoccus host and virus clades observed herein supports species-level host specificity, with strain-level variations in infection parameters

A best-practice position statement on pregnancy after kidney transplantation: focusing on the unsolved questions. The Kidney and Pregnancy Study Group of the Italian Society of Nephrology

Kidney transplantation (KT) is often considered to be the method best able to restore fertility in a woman with chronic kidney disease (CKD). However, pregnancies in KT are not devoid of risks (in particular prematurity, small for gestational age babies, and the hypertensive disorders of pregnancy). An ideal profile of the potential KT mother includes “normal” or “good” kidney function (usually defined as glomerular filtration rate, GFR ≥ 60 ml/min), scant or no proteinuria (usually defined as below 500 mg/dl), normal or well controlled blood pressure (one drug only and no sign of end-organ damage), no recent acute rejection, good compliance and low-dose immunosuppression, without the use of potentially teratogen drugs (mycophenolic acid and m-Tor inhibitors) and an interval of at least 1–2 years after transplantation. In this setting, there is little if any risk of worsening of the kidney function. Less is known about how to manage “non-ideal” situations, such as a pregnancy a short time after KT, or one in the context of hypertension or a failing kidney. The aim of this position statement by the Kidney and Pregnancy Group of the Italian Society of Nephrology is to review the literature and discuss what is known about the clinical management of CKD after KT, with particular attention to women who start a pregnancy in non-ideal conditions. While the experience in such cases is limited, the risks of worsening the renal function are probably higher in cases with markedly reduced kidney function, and in the presence of proteinuria. Well-controlled hypertension alone seems less relevant for outcomes, even if its effect is probably multiplicative if combined with low GFR and proteinuria. As in other settings of kidney disease, superimposed preeclampsia (PE) is differently defined and this impairs calculating its real incidence. No specific difference between non-teratogen immunosuppressive drugs has been shown, but calcineurin inhibitors have been associated with foetal growth restriction and low birth weight. The clinical choices in cases at high risk for malformations or kidney function impairment (pregnancies under mycophenolic acid or with severe kidney-function impairment) require merging clinical and ethical approaches in which, beside the mother and child dyad, the grafted kidney is a crucial “third element”

Quantitative biogeography of picoprasinophytes establishes ecotype distributions and significant contributions to marine phytoplankton

Bathycoccus and Ostreococcus are broadly distributed marine picoprasinophyte algae. We enumerated small phytoplankton using flow cytometry and qPCR assays for phylogenetically distinct Bathycoccus clades BI and BII and Ostreococcus clades OI and OII. Among 259 photic-zone samples from transects and time-series, Ostreococcus maxima occurred in the North Pacific coastal upwelling for OI (36 713 ± 1485 copies ml−1) and the Kuroshio Front for OII (50 189 ± 561 copies ml−1) and the two overlapped only in frontal regions. The Bathycoccus overlapped more often with maxima along Line-P for BI (10 667 ± 1299 copies ml−1) and the tropical Atlantic for BII (4125 ± 339 copies ml−1). Only BII and OII were detected at warm oligotrophic sites, accounting for 34 ± 13 of 1589 ± 448 eukaryotic phytoplankton cells ml−1 (annual average) at Station ALOHA's deep chlorophyll maximum. Significant distributional and molecular differences lead us to propose that Bathycoccus clade BII represents a separate species which tolerates higher temperature oceanic conditions than Bathycoccus prasinos (BI). Morphological differences were not evident, but quick-freeze deep-etch electron microscopy provided insight into Bathycoccus scale formation. Our results highlight the importance of quantitative seasonal abundance data for inferring ecological distributions and demonstrate significant, differential picoprasinophyte contributions in mesotrophic and open-ocean waters. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd

Pregnancy and progression of IgA nephropathy: results of an Italian multicenter study

BACKGROUND: Whether pregnancy impacts on the long-term outcome of immunoglobulin A (IgA) nephropathy is unknown. This study aims to compare the long-term outcome of kidney disease in women with IgA nephropathy and preserved kidney function who did and did not become pregnant. STUDY DESIGN: Multicenter longitudinal cohort study. SETTING & PARTICIPANTS: Women of childbearing age with biopsy-proven IgA nephropathy, serum creatinine level<or=1.2 mg/dL at diagnosis, and minimum follow-up of 5 years after biopsy recruited from 35 nephrology centers participating in a national collaborative study group of pregnancy and kidney disease sponsored by the Italian Society of Nephrology. PREDICTORS: Pregnancy, treated as a time-dependent variable; baseline proteinuria; hypertension; and kidney biopsy histologic characteristics. OUTCOME & MEASURES: Rate of change in estimated creatinine clearance, change in proteinuria, and new-onset hypertension. RESULTS: 245 patients were enrolled. Of these, 223 women (136 and 87 in the pregnancy and nonpregnancy groups, respectively) had serum creatinine levels<or=1.2 mg/dL at diagnosis. Baseline data (including age, estimated creatinine clearance, prevalence of hypertension, and histologic grade of kidney damage) were similar between groups with the exception of proteinuria (protein excretion, 1.33 vs 0.95 g/d in the pregnancy vs nonpregnancy groups, respectively; P=0.03). Kidney function decreased 1.31 mL/min/y (95% CI, 0.99-1.63) during a median follow-up of 10 years (range, 5-31 years) and did not differ between groups. Baseline proteinuria predicted a faster decrease, but did not modify the effect of pregnancy. Pregnancy did not affect changes in proteinuria over time or risk of new-onset hypertension. LIMITATIONS: Unrecognized or unmeasured factors associated with the decision of becoming pregnant might have influenced results. CONCLUSIONS: Pregnancy does not seem to affect the long-term outcome of kidney disease in women with IgA nephropathy and preserved kidney function

Pregnancy and progression of IgA nephropathy: results of an Italian multicenter study

Background: Whether pregnancy impacts on the long-term outcome of immunoglobulin A (IgA) nephropathy is unknown. This study aims to compare the long-term outcome of kidney disease in women with IgA nephropathy and preserved kidney function who did and did not become pregnant. Study Design: Multicenter longitudinal cohort study. Setting & Participants: Women of childbearing age with biopsy-proven IgA nephropathy, serum creatinine level 1.2 mg/dL at diagnosis, and minimum follow-up of 5 years after biopsy recruited from 35 nephrology centers participating in a national collaborative study group of pregnancy and kidney disease sponsored by the Italian Society of Nephrology. Predictors: Pregnancy, treated as a time-dependent variable; baseline proteinuria; hypertension; and kidney biopsy histologic characteristics. Outcome & Measures: Rate of change in estimated creatinine clearance, change in proteinuria, and new-onset hypertension. Results: 245 patients were enrolled. Of these, 223 women (136 and 87 in the pregnancy and nonpregnancy groups, respectively) had serum creatinine levels 1.2 mg/dL at diagnosis. Baseline data (including age, estimated creatinine clearance, prevalence of hypertension, and histologic grade of kidney damage) were similar between groups with the exception of proteinuria (protein excretion, 1.33 vs 0.95 g/d in the pregnancy vs nonpregnancy groups, respectively; P 0.03). Kidney function decreased 1.31 mL/min/y (95% CI, 0.99-1.63) during a median follow-up of 10 years (range, 5-31 years) and did not differ between groups. Baseline proteinuria predicted a faster decrease, but did not modify the effect of pregnancy. Pregnancy did not affect changes in proteinuria over time or risk of new-onset hypertension. Limitations: Unrecognized or unmeasured factors associated with the decision of becoming pregnant might have influenced results. Conclusions: Pregnancy does not seem to affect the long-term outcome of kidney disease in women with IgA nephropathy and preserved kidney function

A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy

Pregnancy is increasingly undertaken in patients with chronic kidney disease (CKD) and, conversely, CKD is increasingly diagnosed in pregnancy: up to 3 % of pregnancies are estimated to be complicated by CKD. The heterogeneity of CKD (accounting for stage, hypertension and proteinuria) and the rarity of several kidney diseases make risk assessment difficult and therapeutic strategies are often based upon scattered experiences and small series. In this setting, the aim of this position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature, and discuss the experience in the clinical management of CKD in pregnancy. CKD is associated with an increased risk for adverse pregnancy-related outcomes since its early stage, also in the absence of hypertension and proteinuria, thus supporting the need for a multidisciplinary follow-up in all CKD patients. CKD stage, hypertension and proteinuria are interrelated, but they are also independent risk factors for adverse pregnancy-related outcomes. Among the different kidney diseases, patients with glomerulonephritis and immunologic diseases are at higher risk of developing or increasing proteinuria and hypertension, a picture often difficult to differentiate from preeclampsia. The risk is higher in active immunologic diseases, and in those cases that are detected or flare up during pregnancy. Referral to tertiary care centres for multidisciplinary follow-up and tailored approaches are warranted. The risk of maternal death is, almost exclusively, reported in systemic lupus erythematosus and vasculitis, which share with diabetic nephropathy an increased risk for perinatal death of the babies. Conversely, patients with kidney malformation, autosomal-dominant polycystic kidney disease, stone disease, and previous upper urinary tract infections are at higher risk for urinary tract infections, in turn associated with prematurity. No risk for malformations other than those related to familiar urinary tract malformations is reported in CKD patients, with the possible exception of diabetic nephropathy. Risks of worsening of the renal function are differently reported, but are higher in advanced CKD. Strict follow-up is needed, also to identify the best balance between maternal and foetal risks. The need for further multicentre studies is underlined