Comparative analysis of thermal indices for modeling cold and heat stress in US dairy systems.

Quantifying the effect of thermal stress on milk yields is essential to effectively manage present and future risks in dairy systems. Despite the existence of numerous heat indices designed to communicate stress thresholds, little information is available regarding the accuracy of different indices in estimating milk yield losses from both cold and heat stress at large spatiotemporal scales. To address this gap, we comparatively analyzed the performance of existing thermal indices in capturing US milk yield response to both cold and heat stress at the national scale. We selected 4 commonly used thermal indices: the temperature-humidity index (THI), black globe humidity index (BGHI), adjusted temperature-humidity index (THIadj), and comprehensive climate index (CCI). Using a statistical panel regression model with observational and reanalysis weather data from 1981 to 2020, we systematically compared the patterns of yield sensitivities and statistical performance of the 4 indices. We found that the US state-level milk yield variability was better explained by the THIadj and CCI, which combine the effects of temperature, humidity, wind, and solar radiation. Our analysis also reveals continuous and nonlinear responses of milk yields to a range of cold to heat stresses across all 4 indices. This implies that solely relying on fixed thresholds of these indices to model milk yield changes may be insufficient to capture cumulative thermal stress. Cold extremes reduced milk yields comparably to those affected by heat extremes on the national scale. Additionally, we found large spatial variability in milk yield sensitivities, implying further limitations to the use of fixed thresholds across locations. Moreover, we found decreased yield sensitivity to thermal stress in the most recent 2 decades, suggesting adaptive changes in management to reduce weather-related risks.

Economic and environmental effects of double cropping winter annuals and corn using the Integrated Farm System Model.

Dairy farms have been under pressure to reduce negative environmental impacts while remaining profitable during times with volatile milk and commodity prices. Double cropping has been promoted to reduce negative environmental impacts and increase total dry matter yield per hectare. Three dairy farms that double cropped winter annuals and corn were selected from northern and western Pennsylvania. Data were collected from recorded crop and dairy records and financial data for 2016 and 2017. Farms ranged in size from 336 to 511 ha with 233 to 663 cows. Data were used to set parameters for the Integrated Farm System Model, which was then used to simulate 8 scenarios for each farm: current operation; 0, 50, and 100% of corn hectares double cropped; 30% feed price increase with and without double cropping; and 30% feed price decrease with and without double cropping at the farm's current level of double cropping. A 20-yr time period, using weather data that was representative of the actual farms, was used in the Integrated Farm System Model simulation to produce both financial and environmental outputs. Double cropping winter annuals and corn silage increased dry matter yield per hectare by 19%, when comparing 0 to 100% of the corn area double cropped. With all corn land double cropped, net return to management per hundredweight (45.36 kg) of milk increased by 1.8%, N leached per hectare per year decreased by an average of 4.5%, and phosphorus loss was reduced by an average of 9.2% across farms. When feed prices increased by 30%, double cropping increased net return over feed cost and net return to management by 1.6 and 2.2%, respectively, across farms. When feed prices decreased by 30%, double cropping decreased net return over feed cost and net return to management by smaller amounts of 0.13% and 0.11%, respectively, across farms. Modeling indicated that double cropping winter annuals with corn silage can have both environmental and economic benefits when winter-annual silage yields are enough to cover expenses.

Genetic effects on birth weight in reciprocal Brahman-Simmental crossbred calves.

Brahman-cross calves exhibit unusual inheritance of birth weight: Brahman-sired crossbreds out of females are heavier with greater difference between sexes than calves of the reciprocal cross. The objectives of this work were to confirm that unusual inheritance and to investigate non-Mendelian genetic effects that may influence differences in Brahman × Simmental crossbred calves. Crossbred calves were produced by embryo transfer ( = 2,862) and natural service or artificial insemination ( = 2,125) from 1983 to 1991 by a private seedstock producer. Brahman-sired F embryos out of Simmental donors weighed 9.4 ± 1.1 ( < 0.001) kg more at birth than Simmental-sired F embryos out of Brahman donor cows when transferred to comparable recipients. This reciprocal difference was accompanied by sexual dimorphism: within Brahman-sired F calves, males were 5.0 ± 1.4 kg heavier than females, whereas within Simmental-sired F calves, females were 0.7 ± 0.5 kg heavier than males. Covariates were constructed from the pedigree to represent genetic effects: proportion Brahman in calves and dams (direct and maternal breed effects), direct and maternal breed heterozygosity, probability of Brahman mitochondrial origin, probability of Brahman Y chromosome, probability of Brahman X chromosome, genomic imprinting (the difference between the probabilities of Brahman in the genetic dam and in the sire), nonrandom X inactivation by breed of origin (the probability of breed heterozygosity of the X chromosomes of a female), and nonrandom X inactivation by parent of origin (the difference between probabilities of a female inheriting a paternal or maternal Brahman X chromosome). The maternal breed heterozygosity, genomic imprinting, probability of Brahman X chromosome, and genomic imprinting × sex effect covariates from the full model were significant with regression coefficients of 1.1 ± 0.5 ( < 0.05), ‒8.3 ± 2.3 ( < 0.01), ‒3.5 ± 1.3 ( < 0.01), and ‒5.3 ± 2.0 ( < 0.01), respectively. Results suggest that sex-specific genomic imprinting may be contributing to the inheritance of birth weight in crossbred calves, similar to patterns of mouse litter and placental weight in interspecific crosses.

Genomic, transcriptional and phenotypic analysis of ftsE and ftsX of Neisseria gonorrhoeae.

Although ftsE and ftsX are not universally present in bacteria, they are present in various Neisseria species as determined by Southern hybridization. The ftsE and ftsX genes of Neisseria gonorrhoeae (Ng) CH811 were cloned, sequenced and were shown to be co-transcribed from two promoters (P(E)1 and P(E)2) which were identified upstream of ftsE(Ng) by primer extension. Sequence analysis of FtsE(Ng) and alignment with other FtsE indicated that it contained the conserved motifs of ABC domains while sequence alignment of FtsX(Ng) with other published FtsX sequences predicted that they all contain four transmembrane segments and a conserved motif (Leu-hydrophobic aa-Gly-Ala/Gly) which may prove to be important for FtsX function. The viability of ftsE(Ng) and ftsX(Ng) mutants that were constructed by insertional inactivation indicated that these genes are not essential. The role of FtsE and FtsX is controversial. Analysis of ftsE(Ng) and ftsX(Ng) mutants by transmission electron microscopy showed that both exhibited morphological abnormalities indicative of defective division sites and in some cases aberrant condensation of DNA.

A novel approach to the laboratory diagnosis of Chlamydia trachomatis infections using monoclonal anti-idiotypic antibodies.

We have developed a novel enzyme immunoassay (EIA) for the specific detection of Chlamydia trachomatis utilizing a monoclonal anti-idiotypic antibody to an antibody directed against a chlamydia specific epitope on 60 kDa heat-shock protein (HSP60). The basis of the assay is the inhibition of the binding of idiotype to anti-idiotype by antigen present in test samples. Two configurations of the assay were developed: a blocking EIA and a competition EIA. Greater sensitivity was observed using the competition EIA, with the assay detecting purified recombinant HSP60 and purified chlamydia in a concentration-dependent manner from 0.01 to 10 micrograms protein and from 0.5 to 12 micrograms total protein, respectively. The assay is highly specific and offers several potential advantages over currently available EIAs for the detection of this pathogen.

Expression of Neisseria gonorrhoeae cell division genes ftsZ, ftsE and minD is influenced by environmental conditions.

The activity of the promoter regions of the cell division genes ftsZ, ftsE, minC, minD and minE from Neisseria gonorrhoeae (Ng) was studied under different environmental conditions using lacZ translational fusions. The promoters of the minNg genes have not been previously determined and we identified promoter regions upstream of each gene (minCp, minDp and minEp). We determined that minDp had the strongest activity. Expression of the promoter regions of ftSZ(Ng) and ftsE(Ng), which we had previously identified, as well as minD(Ng), were then studied under conditions reflecting the environment of the genitourinary tract. These conditions included anaerobiosis, presence of isoleucine or urea (3 mM and 400 mM, respectively) and acidity of pH 6. Both beta-galactosidase expression and northern blot analysis indicated that all three genes were upregulated under anaerobiosis. The addition of isoleucine as well as media at pH 6 did not have any significant effects on the promoter activity of these genes while the presence of urea significantly decreased ftsZ(Ng) promoter activity. The expression of the minD(Ng) promoter region was analyzed during different growth phases and shown to follow the growth behavior of the culture. By contrast, the ftSZ(Ng) promoter activity continued to rise after the onset of the stationary phase. When gonococcal ftsZ promoter 1, (Pz1) was altered by site-directed mutagenesis, a significant decrease in the expression of ftsZ(Ng) was observed under both aerobic and anaerobic conditions. These data infer that gonococci regulate their cell division in response to different environments.

Plasmid analysis and antimicrobial susceptibilities of Peptostreptococcus species.

There are no published methods on plasmid isolation from Peptostreptococcus spp., therefore two methods of plasmid isolation from this genera were analysed: the boiling and alkaline-SDS methods. Plasmid DNA was not recovered by the boiling method, however, with the alkaline-SDS method, cryptic plasmid DNA was detected in two P. asaccharolyticus and one P. magnus strains. To achieve optimum lysis, Peptostreptococcus cells were treated with lysozyme (2 mg/ml) for 15 min. at 37 degrees C followed by proteinase K (0.2 mg/ml) for 1 h at 37 degrees C. In addition we report, the occurrence of clindamycin or metronidazole-resistant peptostreptococci, but these phenotypes were not correlated with plasmid carriage.

Utility of ribotyping, restriction endonuclease analysis and pulsed-field gel electrophoresis to discriminate between isolates of Neisseria gonorrhoeae of serovar IA-2 which require arginine, hypoxanthine or uracil for growth.

Neisseria gonorrhoeae isolates that require arginine--i.e., either citrulline (C), or ornithine (O)--uracil (U) and hypoxanthine (H) have generally been considered to be similar when characterised by auxotype, serovar and plasmid content. The MICs of penicillin, tetracycline, erythromycin, spectinomycin, cefoxitin and ceftriaxone for 552 isolates belonging to serovar IA-2 with these phenotypes were found to be similar. Therefore, restriction fragment length polymorphism analysis of rRNA genes (ribotyping), restriction enzyme (RE) analysis of chromosomal DNA, and pulsed-field gel electrophoresis (PFGE) were evaluated to determine whether these isolates could be distinguished by molecular methods. A subset of 27 isolates of N. gonorrhoeae that were OUH-requiring, CUH-requiring or OH-requiring, belonged to serovar IA-2 and carried a 2.6-MDa plasmid, were selected for further study. Based on the RE analysis of SmaI-digested genomic DNA, the 27 isolates fell into a single RE pattern, five ribotypes and 17 PFGE profiles which did not correlate with the specific arginine-requiring subtypes of these isolates. Each ribotype varied by the presence of only a single fragment, which was of a different size in each pattern, and 17 (63%) of the 27 isolates belonged to ribotype I. PFGE yielded the highest level of discrimination with 17 different profiles.

An analysis of blood lead data in clinical records by external data on lead pipes and age of household.

This study examined the possibility that lead pipes in the drinking water distribution system were elevating the blood lead levels of children in London, Ontario, Canada. Based on their postal codes, 164 children admitted between 1984 and 1989 to an institution for the behaviorally disordered or developmentally challenged were categorized according to whether they lived in the area of the city known by the local Public Utilities Commission to be serviced by lead pipes. Analysis of covariance was used to obtain confounder-adjusted geometric means in each area. After adjusting for gender, year of lead test (a surrogate for gasoline source), and census tract prevalence of low family income, children in the lead service area (LSA) were found not to have higher blood lead levels (geometric means: LSA = 4.7 micrograms/dl, Non-LSA = 4.8 micrograms/dL; p = 0.839). The average blood lead level declined 60.9% between 1984 and 1989. Using municipal tax assessment data on the age of each child's home, those children living in homes built during or before 1945 (when interior paints were as much as 50% lead by dry weight) had an average blood lead level that was 62.3% higher (p = 0.011) than that of those in homes built since 1975 (when interior paints were limited to no higher than 0.5% lead by dry weight). A clear gradient was observed. This association with age of home remained significant after adjusting for gender, diagnosis, and year of lead test. Variables indicating the amount of industry near the child's residence and the presence of lead service pipes did not enter the model after house-age. In conclusion, no evidence indicated that the lead service pipes were elevating blood lead levels in these London children. The data suggest that with the removal of lead from gasoline, lead-based paint is a significant remaining source of lead exposure. Little data are available on childhood lead exposure from paint in Canada. The present descriptive data suggest that more research into this potential problem in Canada is warranted.

Mapping antibiotic-resistant Neisseria gonorrhoeae isolates in Metropolitan Toronto: Issues of scale, positional accuracy and confidentiality.

The primary objective of this paper was to investigate the methodological implications of mapping Neisseria gonorrhoeae using the partial three-digit postal code instead of the complete six-digit postal code. The reporting locations of N gonorrhoeae isolates submitted from hospitals, doctor's offices, private and provincial laboratories, and sexually transmitted disease (STD) clinics were used as a model. Specifically, the paper focused on variations in geographical distributions of STD data when mapped at different aggregations of postal code data and at different map scales. Such variations are of importance to those who analyze the spatial epidemiology of STDs, and the accessibility and use of health care services. This analysis showed that three-digit postal codes are useful in summarizing overall geographic distributions, but greatly reduce positional accuracy, which can lead to inaccurate delineation of service areas and populations served. The six-digit postal code is more appropriate for detailed analysis addressing behavioural issues. The analysis demonstrated that six-digits can be used without breaching individual confidentiality.

Molecular fingerprinting of isolates of the genus Peptostreptococcus using rRNA genes from Escherichia coli and P. anaerobius.

Restriction fragment length polymorphisms (RFLPs) of rRNA genes were evaluated as a tool for intra- and interspecies differentiation of Peptostreptococcus isolates. RFLPs from a collection of 20 clinical isolates and five ATCC strains representing five Peptostreptococcus spp. (P. anaerobius, P. asaccharolyticus, P. magnus, P. micros and P. prevotii) were obtained by hybridization of Southern blots of HindIII- or EcoRI-digested genomic DNA with three probes: probe A, a 0.98 kb HindIII fragment with a partial 16S rRNA gene sequence from P. anaerobius ATCC 27337; probe B, cloned Escherichia coli rrnB operon in plasmid pKK3535; and probe C, E. coli 16S and 23S rRNA. The hybridization patterns varied, but all yielded RFLPs useful for both intra- and inter-species differentiation. RFLPs of P. asaccharolyticus clinical isolates were closely related to each other and differed significantly from those of the ATCC type strains. The profiles of P. prevotii differed from those of the other four species studied, and based on the HindIII- and EcoRI-generated RFLPs, the strains in this species are more heterogeneous than the other four species studied.

Molecular epidemiology and novel combinations of auxotype, serovar, and plasmid content in tetracycline-resistant Neisseria gonorrhoeae isolated in Canada.

Between October 1987 and June 1989, 84 isolates of Neisseria gonorrhoeae carrying the TetM resistance determinant (TRNG) were received at the Laboratory Centre for Disease Control, Ottawa, from six Canadian provinces and were characterized into classes based on auxotype, serovar and plasmid content. One-fifth (17/84) of the TRNG were also penicillinase producing (PPNG). The PPNG-TRNG isolates comprised six classes based on auxotype, serovar, and plasmid content. Most (16/17) PPNG-TRNG carried 3.2-MDa beta-lactamase plasmids and the 25.2-MDa TetM-containing plasmid. We report, for the first time, the association of a 4.5-MDa beta-lactamase plasmid with the 25.2-MDa plasmid in a clinical TRNG isolate. Non-PPNG TRNG isolates comprised 11 classes based on auxotype, serovar, and plasmid content, including two previously unreported auxotype-serovar classes, P/IB-26 and P/IB-20.

Construction of miniplasmids from the 7.2-kb and 5.1-kb penicillinase-producing plasmids of Neisseria gonorrhoeae reveals two replication regions.

Two replication regions have been identified on a 7.2-kb penicillinase-producing plasmid (pJD4) of Neisseria gonorrhoeae. Through construction of mini-plasmids, one replication region of pJD4 was located on a 1.5-kb fragment, designated region "a," that included the unique HindIII site of this plasmid. This region is absent from the 5.1-kb naturally occurring gonococcal penicillinase-producing plasmid (pJD5) which is considered to be a deletion-derivative of the 7.2-kb plasmid. A 1.5-kb fragment (region "b"), part of a 2.5-kb fragment essential for the replication of the 5.1-kb plasmid (pJD5), was found to be responsible for incompatibility. Incompatibility studies showed that in vitro-derived deletion-derivatives from pJD4 and pJD5 containing either region "a" or region "b" were compatible. The DNA sequence of part of region "a" showed that this region was A-T rich. It contained seven sets of A-T rich multiple direct repeats and two putative dnaA boxes, suggesting that the mechanism of replication of region "a" was similar to that of OriC in Escherichia coli.

Cases of Neisseria gonorrhoeae with plasmid-mediated resistance to penicillin increase. The National Study Group.

Penicillinase-producing isolates of Neisseria gonorrhoeae (PPNG) were submitted to the National Laboratory for Sexually Transmitted Diseases for biological and genetic identification as part of an on-going national surveillance program for monitoring antibiotic-resistant gonococci. The primary identification of the isolates was completed in provincial laboratories. The isolates were documented and forwarded to LCDC through the provincial laboratories and provincial epidemiologists. Duplicate isolates from the same patient were excluded from the final analysis; retrospective clinical and epidemiological data were collected for each case. In those cases where PPNG isolates were not available for testing at LCDC, epidemiological and clinical data were included for statistical consideration. These data were collectively analyzed using computer programs developed within the National Laboratory for Sexually Transmitted Diseases.

Evaluation of an enzyme immunoassay and a modified coagglutination assay for typing gonococcal isolates with monoclonal antibodies.

In order to resolve methodologic and interpretation problems associated with the serotyping of Neisseria gonorrhoeae isolates with monoclonal antibodies specific for Protein I (PI) by coagglutination (the standard method; CoA1), two methods were compared with CoA1: an enzyme immunoassay (EIA) and a modified coagglutination assay (CoA2), in which methylene blue was added to the monoclonal antibody reagents. When the EIA was compared with the CoA1 method, 92.7% of the WI isolates were typed identically and 89% of the WII/III isolates were typed identically. When the CoA2 was compared with the CoA1 method, 92.7% of WI isolates were typed into similar serovars, in comparison to only 80.5% of the WII/III isolates. With the EIA method, only 21 of 328 isolates (6.4%) were retested because duplicate results were inconsistent, in comparison to 72 isolates (22%) with the CoA1 method and 120 isolates (36.6%) with the CoA2 method. In most cases result inconsistencies between duplicate tests were due to differences in reading weakly positive coagglutination reactions with single reagents (which on duplicate testing might be negative), the most notable being PIA reagent 4A12(b) and PIB reagents 1F5(b) and 2G2(g). The EIA method was the most reproducible method, and provides some degree of automation when serotyping large numbers of isolates.

Multiple origins and replication proteins influence biological properties of beta-lactamase-producing plasmids from Neisseria gonorrhoeae.

The beta-lactamase-producing Asia-type plasmid pJD4 of Neisseria gonorrhoeae is a 7.4-kb, broad-host-range plasmid. It is part of a family of plasmids which are structurally related yet vary in size, found in both N. gonorrhoeae and Haemophilus ducreyi. Branch-point analysis by electron microscopy indicates that pJD4 carries three clustered but distinguishable origins of replication, which we named ori1, ori2, and ori3. Although pJD4 belongs to incompatibility (Inc) group W, it also carries a silent IncFII determinant which is expressed when ori2 and ori3 are absent. The Africa-type plasmid pJD5, a naturally occurring deletion derivative of pJD4, carries only ori1, belongs to the IncFII group, and, in contrast to pJD4, requires DNA polymerase I (Pol I) for replication. Plasmids constructed from pJD4 which lack ori1 but carry ori2 and ori3 do not require Pol I and are incompatible with IncW plasmids, suggesting that the ori2 or ori3 region contains the IncW determinant. We have cloned a replication initiation protein (RepB) that is necessary for ori2 and ori3 to function. This Rep protein is distinct from RepA, which is necessary for ori1. Thus, pJD4 is unique because it is the smallest plasmid characterized containing three origins of replication and two unique Rep proteins.

Importance of drug resistance in gonococci: from mechanisms to monitoring.

Neisseria gonorrhoeae isolates continue to develop an impressive arsenal of resistance mechanisms to antimicrobial agents, including resistance to some of the antibiotics presently recommended for the treatment of gonococcal infections.

A novel insertion sequence in the cryptic plasmid of Neisseria gonorrhoeae may alter the B protein at the translational level.

A variant of the cryptic plasmid of Neisseria gonorrhoeae, 4.4 kb in size, was isolated and characterized at the molecular level. This variant harbored a 156-bp insertion which was located between coordinates 3134 and 3135 within the putative cppB gene using the 4.2-kb cryptic plasmid, pJD1, as a reference. The insertion contained a novel EcoRI site and several elements of symmetry (both direct and inverted repeats). Stop codons present in the insertion interrupted the coding capacity of the cppB gene. Although the insertion was within one of two previously characterized 44-bp repeats purportedly involved in site-specific recombination, it was distinct from a 54-bp segment deleted in some cryptic plasmids. The presence of the insertion suggests a mechanism of modulating the expression of the cppB gene at the translational level through DNA rearrangement.