Asymmetrical gene flow in five co-distributed syngnathids explained by ocean currents and rafting propensity.

Ocean circulation driving macro-algal rafting is believed to serve as an important mode of dispersal for many marine organisms, leading to predictions on population-level genetic connectivity and the directionality of effective dispersal. Here, we use genome-wide single nucleotide polymorphism data to investigate whether gene flow directionality in two seahorses (Hippocampus) and three pipefishes (Syngnathus) follows the predominant ocean circulation patterns in the Gulf of Mexico and northwestern Atlantic. In addition, we explore whether gene flow magnitudes are predicted by traits related to active dispersal ability and habitat preference. We inferred demographic histories of these co-distributed syngnathid species, and coalescent model-based estimates indicate that gene flow directionality is in agreement with ocean circulation data that predicts eastward and northward macro-algal transport. However, the magnitude to which ocean currents influence this pattern appears strongly dependent on the species-specific traits related to rafting propensity and habitat preferences. Higher levels of gene flow and stronger directionality are observed in Hippocampus erectus, Syngnathus floridae and Syngnathus louisianae, which closely associated with the pelagic macro-algae Sargassum spp., compared to Hippocampus zosterae and the Syngnathus scovelli/Syngnathus fuscus sister-species pair, which prefer near shore habitats and are weakly associated with pelagic Sargassum. This study highlights how the combination of population genomic inference together with ocean circulation data can help explain patterns of population structure and diversity in marine ecosystems.

Knowledge, attitudes, and intentions toward fertility awareness and oocyte cryopreservation among obstetrics and gynecology resident physicians.

STUDY QUESTION: What knowledge, attitudes and intentions do US obstetrics and gynecology (OB/GYN) residents have toward discussing age-related fertility decline and oocyte cryopreservation with their patients? SUMMARY ANSWER: Most OB/GYN residents believe that age-related fertility decline, but not oocyte cryopreservation, should be discussed during well-woman annual exams; furthermore, nearly half of residents overestimated the age at which female fertility markedly declines. WHAT IS KNOWN ALREADY: Oocyte cryopreservation can be utilized to preserve fertility potential. Currently, no studies of US OB/GYN residents exist that question their knowledge, attitudes, and intentions toward discussing age-related fertility decline and oocyte cryopreservation with patients. STUDY DESIGN, SIZE, DURATION: A cross-sectional online survey was conducted during the fall of 2014 among residents in American Council for Graduate (ACOG) Medical Education-approved OB/GYN residency programs. Program directors were emailed via the ACOG Council on Resident Education in Obstetrics and Gynecology server listing and asked to solicit resident participation. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants included 238 residents evenly distributed between post-graduate years 1-4 with varied post-residency plans; 90% of residents were women and 75% were 26-30 years old. The survey was divided into three sections: demographics, fertility awareness, and attitudes toward discussing fertility preservation options with patients. Descriptive and inferential statistics were conducted. MAIN RESULTS AND THE ROLE OF CHANCE: A strong majority of residents (83%) believed an OB/GYN should initiate discussions about age-related fertility decline with patients (mean patient age 31.8), and 73% percent believed these discussions should be part of an annual exam. One third of residents overestimated the age at which there is a slight decline in female fertility, while nearly half of residents overestimated the age at which female fertility markedly declines. Over three-quarters of residents (78.4%) also overestimated the likelihood of success using assisted reproductive treatments (ARTs). Residents were likely to support oocyte cryopreservation in cancer patients irrespective of the woman's age, but much less likely to support elective oocyte cryopreservation. For elective oocyte cryopreservation, 40% believed OB/GYNs should initiate discussions with patients (mean age 31.1), while only 20% believed this topic should be part of an annual exam. LIMITATIONS, REASONS FOR CAUTION: Because the study invitation was sent through US OB/GYN residency program directors rather than directly to residents, it is possible that some residents did not receive the invitation to participate. This limits the generalizability of the findings. WIDER IMPLICATIONS OF THE FINDINGS: Within the USA, there appears to be a critical need for improved education on fertility decline in OB/GYN residency programs. To promote informed reproductive decision-making among patients, efforts should be made to help OB/GYNs provide comprehensive fertility education to all women, while also respecting patient choices. STUDY FUNDING/COMPETING INTERESTS: None.

High-resolution ultrasonography of peripheral nerves: measurements on 14 nerve segments in 56 healthy subjects and reliability assessments.

PURPOSE: The aim of this study was to assess different aspects of reliability in high-resolution ultrasonography (HRUS) of the peripheral nerves and to establish reference values for the most frequently examined nerve segments. MATERIALS AND METHODS: A nerve size parameter, the cross-sectional area (CSA) of the C5, C6 and C7 cervical roots, the median, ulnar, radial, superficial radial, peroneal, tibial, and the sural nerves was measured using HRUS at a total of 14 predefined anatomical sites in two different cohorts of healthy subjects (n = 56), and the inter-rater, intra-rater and inter-equipment reliability of measurements was assessed. RESULTS: The mean CSA of the 14 nerve segments ranged from 2 to 10 mm(2). The intra-rater, inter-rater and inter-equipment reliability was high with intraclass correlation coefficients of 0.93, 0.98, and 0.86, respectively. The CSA values showed no consistent correlation with age, height, and body weight, but males had significantly larger values than females for nerve segments on the arm after correcting for age, weight and height in multivariate analysis. CSA values did not differ when two independent cohorts were compared. CONCLUSION: Peripheral nerve ultrasonography is a reliable and reproducible diagnostic method in the hands of experienced examiners. Normal values for several upper and lower extremity nerves are provided by our study.

The United States dried seahorse trade: A comparison of traditional Chinese medicine and ecommerce-curio markets using molecular identification.

Tens of millions of dried seahorses (genus Hippocampus) are traded annually, and the pressure from this trade along with their life history traits (involved parental care and small migration distances and home ranges) has led to near global population declines. This and other forms of overexploitation have led to all seahorse species being listed in Appendix II under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The signatory nations of CITES recommended a 10-cm size limit of seahorses to ensure harvested individuals have reached reproductive maturity, and have thus had the chance to produce offspring, to maintain a more sustainable global seahorse fishery. We assessed adherence to CITES recommendations using DNA barcoding and size measurements to compare two prominent U.S. dried seahorse markets: (1) traditional Chinese medicine (TCM), and (2) non-medicinal ecommerce and coastal curio (ECC). We also estimated U.S. import abundance from CITES records. Of the nine species identified among all samples (n = 532), eight were found in the TCM trade (n = 168); composed mostly (75%) of the Indo-Pacific species Hippocampus trimaculatus, and Hippocampus spinosissimus, and the Latin American Hippocampus ingens. In contrast, ECC samples (n = 344) included 5 species, primarily juvenile Indo-Pacific Hippocampus kuda (51.5%) and the western Atlantic Hippocampus zosterae (40.7). The majority of TCM samples (85.7%) met the CITES size recommendation, in contrast to 4.8% of ECC samples. These results suggest non-size discriminatory bycatch is the most likely source of imported ECC specimens. In addition, CITES records indicate that approximately 602,275 dried specimens were imported into the U.S. from 2004-2020, but the exact species composition remains unknown as many U.S. imports records list one species or Hippocampus spp. from confiscated shipments due to difficulties in morphological identification and large numbers of individuals per shipment. Molecular identification was used to identify the species composition of confiscated shipment imports containing undesignated species, and similar to TCM, found H. trimaculatus and H. spinosissimus the most abundant. By combining DNA barcoding, size comparisons, and CITES database records, these results provide an important glimpse into the two primary dried U.S. seahorse end-markets, and may further inform the conservation status of several Hippocampus species.

Vici syndrome associated with sensorineural hearing loss and evidence of neuromuscular involvement on muscle biopsy.

Vici syndrome is a rare, genetically unresolved congenital multisystem disorder comprising agenesis of the corpus callosum, cataracts, immunodeficiency, cardiomyopathy, and hypopigmentation. An associated neuromuscular phenotype has not previously been described in detail. We report on an infant with clinical features suggestive of Vici syndrome and additional sensorineural hearing loss. Muscle biopsy revealed several changes including markedly increased variability in fiber size, increased internal nuclei, and abnormalities on Gomori trichrome and oxidative stains, raising a wide differential diagnosis including neurogenic atrophy, centronuclear myopathy (CNM) or a metabolic (mitochondrial) cytopathy. Respiratory chain enzyme studies, however, were normal and sequencing of common CNM-associated genes did not reveal any mutations. This case expands the clinical spectrum of Vici syndrome and indicates that muscle biopsy ought to be considered in infants presenting with suggestive clinical features. In addition, we suggest that Vici syndrome is considered in the differential diagnosis of infants presenting with congenital callosal agenesis and that additional investigation has to address the possibility of associated ocular, auditory, cardiac, and immunologic involvement when this radiologic finding is present.

Search for muon-neutrino to electron-neutrino transitions in MINOS.

This Letter reports on a search for nu(mu) --> nu(e) transitions by the MINOS experiment based on a 3.14x10(20) protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27+/-5(stat)+/-2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of nu(mu) --> nu(e) oscillations, this 1.5sigma excess of events is consistent with sin2(2theta(13)) comparable to the CHOOZ limit when |Delta m2|=2.43x10(-3) eV2 and sin2(2theta(23))=1.0 are assumed.

Initiating patient discussions about oocyte cryopreservation: Attitudes of obstetrics and gynaecology resident physicians.

This study examined the attitudes of obstetrics and gynaecology (OB/GYN) resident physicians to initiating patient discussions regarding medical and elective oocyte cryopreservation (OC). The study used a cross-sectional online survey of OB/GYN medical residents in the USA, sampled from residency programmes approved by the American Council for Graduate Medical Education. In total, 208 medical residents, distributed evenly between postgraduate years 1-4, participated in the study. Residents' fertility knowledge and attitudes to initiating discussions about OC were gathered. Forty percent (n = 83) believed that OB/GYN residents should initiate discussions about OC with patients (initiators), while 60% (n = 125) did not (non-initiators). Initiators were less likely to overestimate the age at which a woman's fertility begins to decline, and were more likely to believe that discussions about OC and age-related fertility decline should take place during a well-woman annual examination. Initiators and non-initiators did not differ in their attitudes towards discussing OC with patients undergoing cancer treatments; however, initiators were significantly more likely to discuss elective OC with patients who were currently unpartnered or who wished to delay childbearing to pursue a career. Given the increasing age of childbearing among women, and the fact that women prefer to receive reproductive information from their healthcare providers, it is critical that such topics are discussed in consultations to assist patients in making more informed reproductive decisions. Further research is needed to assess the existing barriers to these discussions from both physician and patient perspectives.

Low-grade T-cell lymphoma of the kidney and Waldenström's macroglobulinemia in a patient presenting with renal failure.

Renal failure is rarely the presenting manifestation of non-Hodgkin's lymphoma. We describe the unusual case of a patient who presented with uremia due to lymphomatous infiltration of the kidney by a low-grade T-cell lymphoma. The diagnosis of lymphoma was made by renal biopsy. Extrarenal nodular or extra-nodular involvement could not be detected. However, simultaneously, a lymphoplasmacytic lymphoma was found on bone marrow biopsy associated with IgM paraproteinemia. To our knowledge, this is the first report of a renal T-cell lymphoma associated with Waldenström's macroglobulinemia.

Expression and activity of transglutaminase II in spontaneous tumours of dogs and cats.

Tissue transglutaminase II (TGase II) is a dual function protein with both transamidating and guanidine triphosphate (GTP)-binding capabilities. Previous studies have implicated TGase as a pro-apoptotic molecule; however, our recent findings indicate that TGase II may act as a survival factor in various cell types. The purpose of this study was to survey TGase II expression in normal tissue and spontaneous tumours of dogs and cats, by Western blotting and immunohistochemistry. Bladder, liver and adrenal gland exhibited prominent expression of TGase II while other tissues, including mammary gland, displayed limited expression and activity. TGase II GTP-binding in normal tissues was proportional to the level of expression in all tissues examined. Normal mammary tissue and that showing benign hyperplasia did not express TGase II. However, 11/25 (44%) of canine mammary carcinomas and 10/12 (83%) of feline mammary carcinomas strongly expressed TGase II in either a stromal, cellular or combined pattern. The pattern of expression was not related to the classification of mammary carcinoma (solid, tubulopapillary, complex or anaplastic), except that two anaplastic canine mammary carcinomas showed prominent TGase II expression. Two canine mammary carcinoma cell lines showed prominent TGase expression, and when the TGase activity was inhibited, the cells became more sensitive to doxorubicin-induced cell death. Thus, TGase II was significantly expressed in mammary cancers from dogs and cats and immunoreactivity of TGase II was similar to that reported in humans beings. The pro-survival effect of TGase II in canine mammary carcinoma cell lines was similar to that previously reported in humans patients.

Structural basis of inhibitor selectivity in MAP kinases.

BACKGROUND: The mitogen-activated protein (MAP) kinases are important signaling molecules that participate in diverse cellular events and are potential targets for intervention in inflammation, cancer, and other diseases. The MAP kinase p38 is responsive to environmental stresses and is involved in the production of cytokines during inflammation. In contrast, the activation of the MAP kinase ERK2 (extracellular-signal-regulated kinase 2) leads to cellular differentiation or proliferation. The anti-inflammatory agent pyridinylimidazole and its analogs (SB [SmithKline Beecham] compounds) are highly potent and selective inhibitors of p38, but not of the closely-related ERK2, or other serine/threonine kinases. Although these compounds are known to bind to the ATP-binding site, the origin of the inhibitory specificity toward p38 is not clear. RESULTS: We report the structural basis for the exceptional selectivity of these SB compounds for p38 over ERK2, as determined by comparative crystallography. In addition, structural data on the origin of olomoucine (a better inhibitor of ERK2) selectivity are presented. The crystal structures of four SB compounds in complex with p38 and of one SB compound and olomoucine in complex with ERK2 are presented here. The SB inhibitors bind in an extended pocket in the active site and are complementary to the open domain structure of the low-activity form of p38. The relatively closed domain structure of ERK2 is able to accommodate the smaller olomoucine. CONCLUSIONS: The unique kinase-inhibitor interactions observed in these complexes originate from amino-acid replacements in the active site and replacements distant from the active site that affect the size of the domain interface. This structural information should facilitate the design of better MAP-kinase inhibitors for the treatment of inflammation and other diseases.

Population genomics reveals seahorses (Hippocampus erectus) of the western mid-Atlantic coast to be residents rather than vagrants.

Understanding population structure and areas of demographic persistence and transients is critical for effective species management. However, direct observational evidence to address the geographic scale and delineation of ephemeral or persistent populations for many marine fishes is limited. The Lined seahorse (Hippocampus erectus) can be commonly found in three western Atlantic zoogeographic provinces, though inhabitants of the temperate northern Virginia Province are often considered tropical vagrants that only arrive during warm seasons from the southern provinces and perish as temperatures decline. Although genetics can locate regions of historical population persistence and isolation, previous evidence of Virginia Province persistence is only provisional due to limited genetic sampling (i.e., mitochondrial DNA and five nuclear loci). To test alternative hypotheses of historical persistence versus the ephemerality of a northern Virginia Province population we used a RADseq generated dataset consisting of 11,708 single nucleotide polymorphisms (SNP) sampled from individuals collected from the eastern Gulf of Mexico to Long Island, NY. Concordant results from genomic analyses all infer three genetically divergent subpopulations, and strongly support Virginia Province inhabitants as a genetically diverged and a historically persistent ancestral gene pool. These results suggest that individuals that emerge in coastal areas during the warm season can be considered "local" and supports offshore migration during the colder months. This research demonstrates how a large number of genes sampled across a geographical range can capture the diversity of coalescent histories (across loci) while inferring population history. Moreover, these results clearly demonstrate the utility of population genomic data to infer peripheral subpopulation persistence in difficult-to-observe species.

Population Genetic Structure of the Dwarf Seahorse (Hippocampus zosterae) in Florida.

The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of the Gulf of Mexico and is of commercial significance in Florida, where it is harvested for the aquarium and curio trades. Despite its regional importance, the genetic structure of dwarf seahorse populations remains largely unknown. As an aid to ongoing conservation efforts, we employed three commonly applied mtDNA markers (ND4, DLoop and CO1) to investigate the genetic structuring of H. zosterae in Florida using samples collected throughout its range in the state. A total of 1450 bp provided sufficient resolution to delineate four populations of dwarf seahorses, as indicated by significant fixation indices. Despite an overall significant population structure, we observed evidence of interbreeding between individuals from geographically distant sites, supporting the hypothesis that rafting serves to maintain a degree of population connectivity. All individuals collected from Pensacola belong to a single distinct subpopulation, which is highly differentiated from the rest of Floridian dwarf seahorses sampled. Our findings highlight the utility of mtDNA markers in evaluating barriers to gene flow and identifying genetically distinct populations, which are vital to the development of comprehensive conservation strategies for exploited taxa.

PRKACA mediates resistance to HER2-targeted therapy in breast cancer cells and restores anti-apoptotic signaling.

Targeting HER2 with antibodies or small molecule inhibitors in HER2-positive breast cancer leads to improved survival, but resistance is a common clinical problem. To uncover novel mechanisms of resistance to anti-HER2 therapy in breast cancer, we performed a kinase open reading frame screen to identify genes that rescue HER2-amplified breast cancer cells from HER2 inhibition or suppression. In addition to multiple members of the MAPK (mitogen-activated protein kinase) and PI3K (phosphoinositide 3-kinase) signaling pathways, we discovered that expression of the survival kinases PRKACA and PIM1 rescued cells from anti-HER2 therapy. Furthermore, we observed elevated PRKACA expression in trastuzumab-resistant breast cancer samples, indicating that this pathway is activated in breast cancers that are clinically resistant to trastuzumab-containing therapy. We found that neither PRKACA nor PIM1 restored MAPK or PI3K activation after lapatinib or trastuzumab treatment, but rather inactivated the pro-apoptotic protein BAD, the BCl-2-associated death promoter, thereby permitting survival signaling through BCL-XL. Pharmacological blockade of BCL-XL/BCL-2 partially abrogated the rescue effects conferred by PRKACA and PIM1, and sensitized cells to lapatinib treatment. These observations suggest that combined targeting of HER2 and the BCL-XL/BCL-2 anti-apoptotic pathway may increase responses to anti-HER2 therapy in breast cancer and decrease the emergence of resistant disease.

Human Rer1 is localized to the Golgi apparatus and complements the deletion of the homologous Rer1 protein of Saccharomyces cerevisiae.

Sec12p is a type II membrane glycoprotein in the endoplasmic reticulum (ER) of Saccharomyces cerevisiae which is essential for transport vesicle budding. It is the guanine nucleotide exchange factor for the small GTP-binding protein Sar1p which is a constituent of COP II ER to Golgi vesicles. We report the sequence and localization of the human homologue to yeast Rer1p, which has recently been identified genetically as an essential component for retention of Sec12p in the ER. Reverse polymerase chain reaction was used to obtain cDNAs from HeLa cells. They code for a protein of 196 amino acids, corresponding to a molecular mass of 23 kDa. The translated sequence is 44% identical and 65% similar to yeast Rer1 protein. The four putative transmembrane domains are predicted to form a W-topology with both N- and C-terminus facing the cytosol. The functional activity of myc-tagged human Rer1 was demonstrated by the complementation of the RER1 deletion in S. cerevisiae. Mislocalization of the Sec12-reporter protein was reduced similar to the results obtained with yeast Rer1p. Human Rer1 protein was expressed in HeLa cells and the subcellular distribution analyzed by double immunofluorescence and immunoelectron microscopy of thawed cryosections. The tagged protein was localized to the Golgi apparatus and peripheral elements of the ER-Golgi interface. High overexpression leads to relocation of human Rer1 to ER-like structures together with KDEL-receptor and affects the structural organization of the Golgi apparatus. Under conditions of brefeldin A treatment, human Rer1 distributes together with recycling Golgi proteins.

A novel peptide delivery system involving peptidase activated prodrugs as antimicrobial agents. Synthesis and biological activity of peptidyl derivatives of 5-fluorouracil.

As an approach to the development of antimicrobial agents, a novel peptide carrier system was designed, based on the chemical instability of alpha-substituted glycine analogues, with the explicit intent of actively transporting therapeutically useful compounds into microbial cells. Peptides containing 5-fluorouracil (5-FU) linked to the peptide backbone were selected to test the feasibility of this new delivery system. These peptide conjugates were designed such that they would be substrates for both the microbial peptide permeases and peptidases. After entry into cells, enzymatic hydrolysis of the peptide generates an unstable alpha-(5-FU)-glycine that spontaneously decomposes to release 5-FU. The 5-FU-peptide conjugates were tested for antifungal (Candida albicans) and antibacterial (Escherichia coli) activity and were found to have antimicrobial activities comparable to free 5-FU. Noninhibitory peptides antagonized the antimicrobial activities of the 5-FU-peptide conjugates but not of free 5-FU, a result consistent with peptide transport mediated entry of the peptide conjugates into cells. Further support for this conclusion was provided by the finding that biological activities were dependent upon peptide stereochemistry.

Transport of antimicrobial agents using peptide carrier systems: anticandidal activity of m-fluorophenylalanine--peptide conjugates.

A series of di- and tripeptides containing D- and L-m-fluorophenylalanine was prepared and tested in vitro for the ability to inhibit the growth of the yeast Candida albicans. The results demonstrate that peptides containing L-m-fluorophenylalanine inhibited the growth of C. albicans with minimum inhibitory concentrations (MIC's) ranging from 0.5 to 63 micrograms/mL. The parent L-m-fluorophenylalanine and peptides containing D-m-fluorophenylalanine were inactive (MIC greater than 250 micrograms/mL) in these tests. The results of competitive antagonism studies support peptide transport mediated entry of the inhibitory peptides, followed by release of L-m-fluorophenylalanine inside the cell.

Synthesis of structural analogs of leukotriene B4 and their receptor binding activity.

Structural analogs of leukotriene B4 (LTB4) were designed using a preferred conformation of LTB4 (1). Appending an aromatic ring scaffold between LTB4 carbons 7 and 11 led to quinoline analogs 3 and 15. A similar modification to the LTB4 structure between carbons 7 and 9 led to the pyridine analogs 41 and 46. The compounds of this study were evaluated in receptor binding assays using [3H]LTB4 and intact human DMSO differentiated U-937 cells. The first analog prepared, quinoline 3, displayed moderate potency in the LTB4 receptor binding assay (Ki = 0.9 microM). Modification of 3 by appending an aromatic ring between carbons 2 and 4 of the acid side chain produced a dramatic increase in receptor binding (15, Ki = 0.01 microM); a further improvement in receptor binding was achieved in the pyridine series (e.g., 41; Ki = 0.001 microM). The LTB4 receptor agonist/antagonist activity of the test compounds was determined using a functional assay that relies upon intracellular calcium mobilization induced by LTB4. Of the analogs prepared in this report only 47 demonstrated LTB4 receptor antagonist activity.

Synthesis and LTB4 receptor antagonist activities of the naturally occurring LTB4 receptor antagonist Leucettamine A and related analogues.

The isolation and structure determination of the naturally occurring LTB4 receptor antagonist Leucettamine A (1) was recently reported. Herein we describe the synthesis of this natural product, the preparation of several analogues, and their effectiveness as antagonists of [3H]LTB4 binding to intact human U-937 cells. Total synthesis of Leucettamine A (1) is achieved by a convergent route which takes advantage of the elements of symmetry within the molecule. Syntheses of analogues of 1, which lacked the same degree of symmetry, are achieved by a different approach starting from alpha-amino acids. The natural product 1 inhibits [3H]LTB4 binding to its receptors on intact human U-937 cells with a Ki = 3.5 +/- 0.8 microM and is devoid of measurable agonist activity at the concentrations tested. 2-Amino imidazole analogues of 1 lacking the dioxolane groups were prepared. Generally these are significantly less potent than 1. However, one (26), designed on the basis of a putative structural overlay with LTB4, demonstrated potency comparable to that of the natural product (Ki = 2.4 +/- 0.2 microM).

Semisynthetic cephalosporins. Synthesis and structure-activity relationships of analogues with 7-acyl groups derived from 2-(cyanomethylthio)acetic acid or 2-[(2,2,2-trifluoroethyl)thio]acetic acid and their sulfoxides and sulfones.

The synthesis and in vitro and in vivo activities of a series of cephalosporins having side chains derived from 2-[(2,2,2-trifluoroethyl)thio]acetic acid or 2-(cyanomethylthio)acetic acid and with acetoxymethyl or 3-heterocyclic thiomethyl substituents at the 3 position are described. In both series, increasing the oxidation state of the side-chain sulfur atom from sulfide to sulfoxide/sulfone decreased the in vitro gram-positive activity, but the effect on gram-negative activity was variable and less pronounced. The protective effectiveness in mice infected with Escherichia coli increased as the oxidation level of the side-chain sulfur was raised from sulfied to sulfoxide/sulfone. Replacement of the 3-acetoxymethyl by a 3-heterocyclic thiomethyl group resulted in overall improvement of activity both in vitro and in vivo for all oxidation states.