The Cuatro Cié negas Basin (CCB) in the central part of the Chihuahan desert (Coahuila, Mexico) hosts a wide diversity of microorganisms contained within springs thought to be geomorphological relics of an ancient sea. A major question remaining to be answered is whether bacteria from CCB are ancient marine bacteria that adapted to an oligotrophic system poor in NaCl, rich in sulfates, and with extremely low phosphorus levels (<0.3 M). Here, we report the complete genome sequence of Bacillus coahuilensis, a sporulating bacterium isolated from the water column of a desiccation lagoon in CCB. At 3.35 Megabases this is the smallest genome sequenced to date of a Bacillus species and provides insights into the origin, evolution, and adaptation of B. coahuilensis to the CCB environment. We propose that the size and complexity of the B. coahuilensis genome reflects the adaptation of an ancient marine bacterium to a novel environment, providing support to a ''marine isolation origin hypothesis'' that is consistent with the geology of CCB. This genomic adaptation includes the acquisition through horizontal gene transfer of genes involved in phosphorous utilization efficiency and adaptation to high-light environments. The B. coahuilensis genome sequence also revealed important ecological features of the bacterial community in CCB and offers opportunities for a unique glimpse of a microbe-dominated world last seen in the Precambrian.evolution ͉ genomic adaptation ͉ horizontal gene transfer ͉ phosphorus stress ͉ sulfolipids T he Cuatro Ciénegas Basin (CCB) is located in a valley Ϸ740 m above sea level in the state of Coahuila, Mexico, that measures Ϸ30 km by 40 km and is surrounded by high mountains (Ͼ3,000 m) (Fig. 1). CCB is an enclosed evaporitic basin that receives Ϸ150 mm of annual precipitation. Despite the dry climate of the valley, the CCB harbors an extensive system of springs, streams, and pools (1). The CCB ecosystem is not only characterized by a high endemism of macrooganisms and biodiversity of microorganisms (1, 2), but also by extremely oligotrophic waters that are unable to sustain algal growth, making microbial mats the base of the food web (3). In particular, phosphorus (P) levels in CCB appear to be rather low, because they were below the level of detection of several methods used (0.3 M) and the extremely high biomass C:P and N:P ratios (Ͼ100 by moles) previously reported for CCB stromatolites (3, 4). Unlike the present sea, the Churince spring water is poor in NaCl and carbonates, but it is rich in sulfates, magnesium, and calcium (4). Characterization of the microbiological diversity by sequencing 16S rRNA genes revealed that nearly half of the phylotypes from the CCB were closely related to bacteria from marine environments (2). Bacillus coahuilensis is a free-living, spore-forming bacteria isolated from the water column of a shallow desiccation lagoon in the Churince system at CCB (4) (Fig. 1 A and B). A molecular phylogenetic analysis of 16S rRNA sequences indicates that B. coahuilensis is closely ...

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Worldwide recognition of the Zika virus outbreak in the Americas was triggered by an unexplained increase in the frequency of microcephaly. While severe microcephaly is readily identifiable at birth, diagnosing less severe cases requires comparison of head circumference (HC) measurement to a growth chart. We examine measured values of HC and digit preference in those values, and, by extension, the prevalence of microcephaly at birth in two data sources: a research study in Honduras and routine surveillance data in Uruguay. The Zika in Pregnancy in Honduras study enrolled pregnant women prenatally and followed them until delivery. Head circumference was measured with insertion tapes (SECA 212), and instructions including consistent placement of the tape and a request to record HC to the millimeter were posted where newborns were examined. Three indicators of microcephaly were calculated: (1) HC more than 2 standard deviations (SD) below the mean, (2) HC more than 3 SD below the mean (referred to as “severe microcephaly”) and (3) HC less than the 3rd percentile for sex and gestational age, using the INTERGROWTH-21st growth standards. We compared these results from those from a previous analysis of surveillance HC data from the Uruguay Perinatal Information System (Sistema Informático Perinatal (SIP). Valid data on HC were available on 579 infants, 578 with gestational age data. Nine babies (1.56%, 95% CI 0.71–2.93) had HC < 2SD, including two (0.35%, 95% CI 0.04–1.24) with HC < 3SD, and 11 (1.9%, 95% CI, 0.79–3.02) were below the 3rd percentile. The distribution of HC showed strong digit preference: 72% of measures were to the whole centimeter (cm) and 19% to the half-cm. Training and use of insertion tapes had little effect on digit preference, nor were overall HC curves sufficient to detect an increase in microcephaly during the Zika epidemic in Honduras. When microcephaly prevalence needs to be carefully analyzed, such as during the Zika epidemic, researchers may need to interpret HC data with caution.

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The impact of Zika virus (ZIKV) infection on pregnancies shows regional variation emphasizing the importance of studies in different geographical areas. We conducted a prospective study in Tegucigalpa, Honduras, recruiting 668 pregnant women between July 20, 2016, and December 31, 2016. We performed Trioplex real-time reverse transcriptase–PCR (rRT-PCR) in 357 serum samples taken at the first prenatal visit. The presence of ZIKV was confirmed in seven pregnancies (7/357, 2.0%). Nine babies (1.6%) had microcephaly (head circumference more than two SDs below the mean), including two (0.3%) with severe microcephaly (head circumference [HC] more than three SDs below the mean). The mothers of both babies with severe microcephaly had evidence of ZIKV infection. A positive ZIKV Trioplex rRT-PCR was associated with a 33.3% (95% CI: 4.3–77.7%) risk of HC more than three SDs below the mean.