Free triiodothyronine (T3) is negatively associated with fasting ghrelin serum levels in a population sample of euthyroid subjects.

PURPOSE: Ghrelin is an orexigenic peptide hormone secreted in times of stress and hunger. It is deeply involved in the regulation of metabolism and energy homeostasis, promoting energy intake and inhibiting energy expenditure on a metabolic level. In this regard, it has in many ways antagonistic effect on the thyroid hormones, which increase metabolism and thus energy expenditure. While there is reasonable evidence of a negative association between ghrelin and hormones of the hypothalamic-pituitary-thyroid (HPT-) axis from studies in patients with thyroid dysfunction and small intervention studies, large-scale studies in healthy subjects are lacking. Therefore, we studied the relationship between total ghrelin serum levels and serum levels of the thyroid hormones in a large sample of euthyroid subjects. METHODS: Total ghrelin, thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) were determined after an overnight fast in 1666 subjects participating in a population-based cross-sectional study ('LIFE') including 10,000 adults. 1012 subjects were included in this analysis. Multiple linear regression analyses were performed. RESULTS: FT3 was negatively associated with serum ghrelin; total sample: ß = - 0.0001, p < 0.001; men: ß = - 0.0002, p = 0.013; women: ß = - 0.0001, p = 0.010, adjusted for age, BMI, alcohol consumption, serum levels of TSH and fT4 and smoking status. No associations were found between ghrelin serum levels and serum levels of fT4 or TSH. CONCLUSION: This is to date the largest study investigating the relationship between total serum ghrelin and thyroid hormones. The results point to a complex interaction and should initiate further research.

High prevalence of comorbidities and use of concomitant medication in treated people living with HIV in Germany - results of the BESIDE study.

Due to demographic changes in people living with HIV (PLHIV), physicians are challenged with age-related comorbidities and their management. In the absence of comprehensive data collection, the burden of comorbidities and co-medication in addition to antiretroviral therapy (ART) remains unclear for the German real-world setting. BESIDE was an observational, cross-sectional study evaluating the prevalence of comorbidities and use of co-medication in treated PLHIV. Regional distribution of study centers (n = 20), consecutive patient recruitment, and age-stratified sampling in alignment with national epidemiologic data aimed to ensure a representative sample (n = 453). The overall prevalence of comorbidities was 91.2%; 31.6% of patients had ≥4 comorbidities. The most common diagnoses were vitamin D deficiency (29.1%), depressive episode (27.8%), arterial hypertension (16.3%), and hypercholesterolemia (10.8%). 83.7% of patients were on co-medication; 21.2% taking ≥4 medications. The most common medications or supplements were vitamins (31.6%), anti-inflammatory agents (16.1%), renin-angiotensin system agents (12.1%), acid suppressants (11.7%), lipid modifying agents (10.8%); 1.3% of patients were on co-medication that should not be co-administered with ART, 41.5% on co-medication with potential for drug-drug interactions. The prevalence of comorbidities and use of co-medication among treated PLHIV in Germany is consistently high and increases across age groups, illustrating the complexity of HIV care involving appropriate ART selection.

High prevalence of recreational and illicit drug use in German people living with HIV with a potential for drug-drug interactions with antiretroviral therapy.

Recreational drug use is higher in people living with HIV (PLHIV) than in the general population in Europe. This use increases the risk for drug-drug interactions (DDIs) and adverse events. We assessed the prevalence and clinical consequences of substance abuse among PLHIV. BESIDE was a cross-sectional, multi-center study in 2016/18, evaluating comorbidities, polypharmacy and recreational/illicit drug use in PLHIV on antiretroviral therapy (ART) in Germany. Legal and illicit drug use was recorded using two anonymous patient questionnaires one year apart (Q1 and Q2). The BESIDE study population consisted of 453 PLHIV (22% female, median age 46 years). Recreational drug use was reported by the majority (Q1: ever used 73%, within previous 6 months 56%): nitrite inhalants ("poppers"), cannabis and PDE-5 inhibitors were common across all age groups; ecstasy, (meth-)amphetamine and gamma-hydroxybutyrate/gamma-butyrolactone were predominantly reported by younger PLHIV. Based on Q2, two-thirds of PLHIV (67%) had been informed about potential risks of drug abuse by their doctors, whereas one-third (33%) had talked to their doctors on their own initiative with only 7% considering drug use in combination with ART a problem. Strikingly, 44% and 42% had undergone medical treatment or had been hospitalized due to drug use. These data emphasize the high clinical relevance of recreational drug use in PLHIV and the need for treating physicians to pro-actively communicate the potential risks.

Serum BDNF levels correlate with regional cortical thickness in minor depression: a pilot study.

Serum brain-derived neurotrophic factor (BDNF) reflects state changes in mood disorders. But its relation to brain changes in depression has rarely been investigated in humans. We assessed the association between serum BDNF, cortical thickness, or gray matter volume in 20 subjects with a minor depressive episode and 40 matched healthy subjects. Serum BDNF positively correlated with cortical thickness and volume in multiple brain regions in the minor depression group: the bilateral medial orbitofrontal cortex and rostral anterior cingulate cortex, left insula, and cingulum, right superior frontal gyrus, and other regions-regions typically affected by major depression. Interestingly, these correlations were driven by subjects with first episode depression. There was no significant association between these imaging parameters and serum BDNF in the healthy control group. Interaction analyses supported this finding. Our findings point to a specific association between serum BDNF and magnetic resonance imaging parameters in first-episode minor depression in a region- and condition-dependent manner. A positive correlation between serum BDNF and structural gray matter estimates was most consistently observed for cortical thickness. We discuss why cortical thickness should be preferred to volumetric estimates for such analyses in future studies. Results of our pilot study have to be proven in future larger-scale studies yielding higher statistical power.

Similar efficacy and tolerability of raltegravir-based antiretroviral therapy in HIV-infected patients, irrespective of age group, burden of comorbidities and concomitant medication: Real-life analysis of the German 'WIP' cohort.

Only limited efficacy and tolerability data on raltegravir (RAL) use are currently available. Study objectives were to describe the efficacy and tolerability profile of RAL-based antiretroviral therapy (ART) in routine clinical practice in Germany. The WIP study (WIP = "Wirksamkeit von Isentress unter Praxisbedingungen", Efficacy of Isentress under routine clinical conditions) was a prospective, multi-centre cohort study in Germany. Human immunodeficiency virus (HIV)-infected patients aged ≥ 18 years in whom combinational ART with RAL 400 mg BID was indicated were enrolled. The primary endpoint was virologic response (HIV-RNA <50 copies/mL; non-completion equals failure) after 48 weeks. Of 451 patients, 85.1% (n = 384) were still receiving RAL at week 48. At baseline (BL), the prevalence of concomitant diseases was higher in patients of the age group ≥50 years (94.2% vs. 75.7%) as well as concomitant medications (74.8 % vs. 55.4%). Virologic response at week 48 was 74.7% (overall), 75.0% (naïve at BL), 81.5% (suppressed at BL), 47.1% (interrupted previous treatment at BL) and 64.9% (failing at BL), without significant differences by age group. A significant correlation of achievement of HIV-RNA <50 copies/mL was seen with treatment status at BL (p = 0.004). In addition, 77.3 % of the patients with a CD4 cell count >200 cells/µL at BL achieved HIV-RNA <50 copies/mL (p = 0.029). RAL was well tolerated with 80 adverse events (AEs) in 49 patients (10.9%) and 8 serious AEs (SAEs) in 6 patients (1.3%) reported to be drug related. A total of 22 patients (4.9%) discontinued treatment due to AEs. The WIP study shows that the previously reported efficacy and safety profile of RAL can be achieved in a population with multiple comorbidities and comedications, with no major difference observed in ageing patients (≥50 years) vs. younger patients. RAL is therefore an attractive treatment option in routine medical care in Germany.

Genetic Variants of the FADS Gene Cluster Are Associated with Erythrocyte Membrane LC PUFA Levels in Patients with Mild Cognitive Impairment.

BACKGROUND: Long-chain (> 20 C-atoms) polyunsaturated fatty acids (LC PUFAs) of both the omega-6 (n-6) and omega-3 (n-3) series are important for the functional integrity of brain and thereby cognition, memory and mood. Clinical studies observed associations between altered LC PUFA levels and neurodegenerative diseases such as Alzheimer´s disease and its prodromal stage, mild cognitive impairment (MCI). METHODS: The present study examined the LC PUFA status of MCI patients with specific view on the relative LC n-3 PUFA levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocyte membranes (omega-3 index). 12 single nucleotide polymorphisms (SNPs) of the FADS1, FADS2, and FADS3 gene clusters were genotyped in 111 MCI patients and evaluated associations with PUFA levels in erythrocyte membranes (primary outcome). In addition, the associations between FADS SNPs and LC PUFA levels with serum lipid levels as well as depressive symptoms were examined (secondary outcomes). RESULTS: Minor allele carrier of rs174546, rs174548 (FADS1), rs3834458, rs1535, rs174574, rs174575, rs174576, and rs174578 (FADS2) showed significant higher n-6 and n-3 precursor PUFA levels (linoleic acid, and alpha-linolenic acid, respectively) and lower arachidonic acid (AA) levels in erythrocyte membranes compared to the major allele carriers. Differences in EPA and DHA levels were not significant. Minor allele carriers of rs174574, rs174576 and rs174578 (FADS2) and rs174455 (FADS3) exhibited significant higher triglyceride levels, whereas minor allele carriers for rs174449 and rs174455 (FADS3) exhibited significant higher total- and LDL-cholesterol levels compared to the more common variant. The mean omega-3 index of the study cohort was 6.19 ± 1.55 %. In more than 85 % of the patients, the omega-3 index was below 8 % and in 23 % below 5 %. Moreover, it was shown that a low DHA status and omega-3 index was associated with depressive symptoms (Beck's depression-inventory). DISCUSSION AND CONCLUSION: These findings indicate an association between several FADS genotypes for higher n-6 and n-3 precursor PUFA and lower AA levels in erythrocyte membranes in minor compared to major allele carriers. To what extent FADS genotypes and a lower conversion of LA and ALA to biologically important LC PUFAs such as AA, EPA and DHA contributes to cognitive decline should be investigated in further trials. Nevertheless, the omega-3 index in this cohort of MCI patients can be classified as insufficient.

[Evaluation of the self-tonometer Icare ONE in comparison to Goldmann applanation tonometry]. / Evaluation des Selbsttonometers Icare ONE im Vergleich mit der Goldmann-Applanationstonometrie.

OBJECTIVE: The aim of this clinical study was to demonstrate the practicability of self-measured intraocular pressure and to evaluate the reliability by comparing the data with those obtained by Goldmann applanation tonometry (GAT). METHODS: A total of 40 patients aged between 44 and 82 years with glaucoma were introduced to the handling of the tonometer. The self-measurements were done for 1-3 days following the medical measurement by GAT. The data were saved as "correct" or in the case of wrong handling as "false". The impressions of the patients were obtained by a questionnaire. RESULTS: A total number of 191 single measurements were registered by the Icare ONE and of these there were 97 (50.8%) signed "false". Of the patients 45% reached a maximum difference of ±5 mmHg between GAT and self-measurement in every single measurement. In the subgroup of under 60-year-old patients 70% reached this result. There were no indications of a systematic error. Of the probands 60% considered the handling of the Icare ONE as difficult. Nevertheless, 80% could imagine using the self-tonometer at home. CONCLUSIONS: The differences between the self-measurements and the GAT were highly fluctuating in some cases. In the group of patients younger than 60 years the agreement was better, so problems with the handling of the Icare ONE may be an important factor. However, the acceptance in the patients tested was high and continuous pressure measurements at home could be reasonable. Advancements in the handling and reliability are needed to improve clinical application of the measured values.

[Lifestyle and cognition: what do we know from the aging and neurodegenerative brain?]. / Lebensstil und Kognition: Was wissen wir über das alternde und neurodegenerativ veränderte Gehirn?

Epidemiological studies demonstrated positive effects of continuous physical activity and balanced diet on cardiovascular fitness. In chronic neurodegenerative disorders, e.g. Parkinson's disease and Alzheimer's disease, physical activity has become a successful supportive symptomatic therapy. However, it has become evident that physical activity not only improves motor symptoms but also has high impact on cognition in both (elderly) healthy brain and neurodegenerative alterations in the CNS. Nutrition also has been reported to exert positive effects on brain function.Animal studies indicate an increased endogenous plasticity as the underlying mechanism in terms of activation of neuronal precursor cells in different brain areas, leading to improved brain function.First experimental studies in humans also show that physical activity and balanced nutrition increase the release of neurotrophic factors in the brain, increase the volume of grey matter in learning- and memory-associated brain regions and improve cognitive function. This phenomenon opens up noninvasive causal therapeutic options in neurodegenerative disorders and during aging-associated cognitive decline by inducing changes in lifestyle. This option could provide a socioeconomically and ethically reasonable treatment for neurodegenerative disorders.The presented article summarizes the current knowledge from animal experiments and studies in humans. It provides an overview of potential cellular and molecular candidate mechanisms and discusses novel translational clinical studies and first clinical applications.

Strong differences in chemical recognition cues between two closely related species of ants from the genus Lasius (Hymenoptera: Formicidae).

Cuticular hydrocarbons (CHCs) are increasingly recognized as important to insects and are used for constructing taxonomies. However, multiple parameters affect the expression of CHCs besides a genetic component. We propose that selection may act differently on the expression of CHCs, depending on the evolutionary context. To explore the influence of selection, the CHCs of two closely related ant species, Lasius niger and Lasius platythorax, were studied in a multidisciplinary approach. We characterized (i) CHCs and (ii) niches (through baiting, activity observations and foraging analysis). The species were distinct in both measures, although to a varying degree. Although they showed moderate niche partitioning along diet and environmental preferences, chemical differences were unexpectedly pronounced. This may be explained by divergent selection on mate recognition cues or by other influences on CHCs. Such striking chemical differences among closely related species may not be the rule and suggest that taxonomies based on CHCs should be interpreted cautiously; though, they remain useful tools for differentiating among cryptic species.

Impact of common KIBRA allele on human cognitive functions.

The rs17070145 polymorphism (C → T substitution, intron 9) of the KIBRA gene has recently been associated with episodic memory and cognitive flexibility. These findings were inconsistent across reports though, and largely lacked gene-gene or gene-environment interactions. The aim of the present study was to determine the impact of the rs17070145 polymorphism on clinically relevant cognitive domains and its interaction with the modifiers 'lifestyle' and 'cardiovascular risk factors'. Five-hundred forty-five elderly volunteers (mean age 64 years, ±7 years, 56% women) accomplished a comprehensive cognitive testing. Principal component analysis was used to reveal the internal structure of the data, rendering four composite scores: verbal memory, word fluency, executive function/psychomotor speed, and working memory. Lifestyle was assessed with a detailed questionnaire, age-associated risk factors by clinical interview and examination. There was no main effect of the rs17070145 genotype on any cognitive composite scores. However, we found worse performance in executive functions for T-allele carriers in the presence of arterial hypertension (ß=-0.365, p=0.0077 and 0.031 after Bonferroni correction). This association was further modified by gender, showing the strongest association in hypertensive females (ß=-0.500, p=0.0072 and 0.029 after Bonferroni correction). The effect of KIBRA on cognitive function seems to be complex and modified by gender and arterial hypertension.

[Three-dimensional visualization of sclerotomies with ultrasound biomicroscopy. Comparison of 20 and 23 gauge incisions on the porcine eyeball]. / Dreidimensionale Darstellung von Sklerotomien mittels Ultraschallbiomikroskopie : Vergleich von 20- und 23-Gauge-Inzisionen am Schweinebulbus.

BACKGROUND: When pars plana vitrectomy is performed, the sizes of the sclerotomy cannula vary between 20 and 23 gauge. We examined the morphology of the scleral tunnels by ultrasound biomicroscopy additionally taking into account the incision angle. MATERIAL AND METHODS: In each of 16 enucleated porcine eyes three 20 or 23 gauge sclerotomies with varying angles between 30 and 90° to the horizontal level were performed. The vertical 20 gauge sclerotomies were additionally sealed by 7.0 vicryl cross-stitching. The resulting scleral channels were analysed by 3-D ultrasound biomicroscopy. RESULTS: The sclerotomies were echographically detectable in all cases. Analysis revealed that the sutured straight 20 gauge tunnels were hyporeflective in only some parts while the other incisions showed continuous hyporeflectivity along the complete channel in many cases. The smaller the instruments used and the flatter the scleral angles chosen, the smaller were the measured widths of the incision tunnels. CONCLUSION: Imaging sclerotomies ex vivo by ultrasound biomicroscopy is reliably reproducible. In the echographic pictures straight 20 gauge incisions appeared to be safely sealed by the sutures while the nonsealed tunnels often showed continuous patency. By choosing small instruments and flat incision angles the width of the resulting scleral channels can be reduced.

[Progressive corneal opacity after autologous keratoplasty]. / Progrediente Hornhauttrübung nach autologer Keratoplastik. Diagnose: Epitheliale Zellaussaat in die Vorderkammer nach autologer Keratoplastik.

A 55-year-old woman underwent autologous keratoplasty because of band keratopathy and corneal decompensation of the left eye. Previously recurring events of uveitis had affected the eye. A vitrectomy had been performed on the left side for tractional retinal detachment of the posterior pole. The visual acuity of the right donor eye had been reduced to hand movements after occlusion of the central retinal artery. Twelve months after the transplantation, a circumscribed opacity appeared on the endothelial side of the cornea. Cells in the anterior chamber were detected, as well as a moderate rise in ocular tension. Despite intensive anti-inflammatory therapy, the membrane extended over the complete cornea. We diagnosed an ingrowth of epithelial cells as responsible for the changes.

HIV-1 Nef associated PAK and PI3-kinases stimulate Akt-independent Bad-phosphorylation to induce anti-apoptotic signals.

A highly conserved signaling property of Nef proteins encoded by human or simian immunodeficiency virus is the binding and activation of a PAK kinase whose function is unclear. Here we show that Nef-mediated p21-activated kinase (PAK) activation involves phosphatidylinositol 3-kinase, which acts upstream of PAK and is bound and activated by Nef similar to the manner of Polyoma virus middle T antigen. The Nef-associated phosphatidylinositol-3-PAK complex phosphorylated the pro-apoptotic Bad protein without involving the protein kinase B-Akt kinase, which is generally believed to inactivate Bad by serine phosphorylation. Consequently, Nef, but not a Nef mutant incapable of activating PAK, blocked apoptosis in T cells induced by serum starvation or HIV replication. Nef anti-apoptotic effects are likely a crucial mechanism for viral replication in the host and thus in AIDS pathogenesis.

Clostripain linker deletion variants yield active enzyme in Escherichia coli: a possible function of the linker peptide as intramolecular inhibitor of clostripain automaturation.

The clostripain core protein is composed of the light and heavy chain subunits linked by a nonapeptide into a single polypeptide chain [Mol. Gen. Genet. 240: 140, 1993]. Linker removal is due to autocatalytic processing yielding active heterodimeric enzyme. We have expressed mutationally altered core protein variants in the heterologous host Escherichia coli to gain further insight into the process of clostripain automaturation. In a mutationally created Cys231 --> Ser variant, heterodimer formation was largely impaired, providing molecular evidence that the capacity for automaturation is attributed to the active site cysteine, Cys231, of the native enzyme. Artificially generated deletions of the linker peptide did not prevent the formation of active enzyme. One variant gave rise to a single-chain molecule devoid of the authentic processing sites while retaining enzymatic activity. Experiments performed with linker substitution variants suggested that the efficacy of automaturation depends on a proper configuration of the linker region. According to computerized predictions, the formation of a turn-structured protein loop or hinge with hydrophilic characteristics in the linker region is probably a prerequisite for the interaction of the active site cysteine with the processing sites, Arg181 and Arg190. We propose that the clostripain linker nonapeptide serves as an important transient intramolecular inhibitor in the cellular self-defense program evolved by the natural host Clostridium histolyticum.

Heterologous expression of the clostripain gene from Clostridium histolyticum in Escherichia coli and Bacillus subtilis: maturation of the clostripain precursor is coupled with self-activation.

Clostripain-specific antibodies were used to analyse the maturation of clostripain prepro-enzyme and core protein heterologously synthesized in Escherichia coli and Bacillus subtilis. Core protein purified from E. coli cells harbouring plasmid pHM3-23 underwent calcium-dependent, self-triggered maturation. Concomitantly, the inactive form of the enzyme was converted into an active form, demonstrating the self-activation capacity of the clostripain core protein. As judged from Western blot analysis, the major portion of the protein in E. coli was degraded, presumably by the activated clostripain. The enzyme was not exported to the E. coli periplasm, either by use of the putative Clostridium histolyticum signal peptide or by use of the E. coli OmpA signal peptide. Therefore, the Gram-positive micro-organism B. subtilis was chosen as an alternative host for the expression of the prepro-enzyme and the core protein. BR 151 cells harbouring pHM7-10B secreted clostripain precursor to the growth medium and matured subsequently to the active enzyme. As only a small amount of activity was detected intracellularly, the putative C. histolyticum signal peptide was efficiently recognized by the B. subtilis secretion apparatus. Under optimized conditions, a level of 4500 U I-1 could be obtained in batch cultures.

Cloning of proline-specific endopeptidase gene from Flavobacterium meningosepticum: expression in Escherichia coli and purification of the heterologous protein.

Proline-specific endopeptidase (PSE) (EC 3.4.21.26) from Flavobacterium meningosepticum was subjected to partial amino acid sequencing. According to the peptide sequences obtained, oligonucleotides were used to amplify a PSE-specific DNA fragment of 930 bp from F. meningosepticum genomic DNA, employing the polymerase chain reaction technique. This fragment served as a molecular probe to isolate the respective gene. DNA sequencing revealed that the PSE gene consists of 2118 bp coding for a 78,634 Da protein of 705 amino acids. The coding region was cloned in different expression vectors of Escherichia coli. Transformed E. coli cells overproduce an active prolyl endopeptidase of 75,000 relative molecular mass, which is delivered to the bacterial periplasmic space. Up to 1.6 units of active prolyl endopeptidase were obtained from 1 mg E. coli cells. Furthermore, the efficient purification of active prolyl endopeptidase from the periplasm of recombinant E. coli cells is described.

The heterodimeric protease clostripain from Clostridium histolyticum is encoded by a single gene.

Clostripain (EC 3.4.22.8) is a heterodimeric cysteine endopeptidase with strict specificity for Arg-Xaa peptidyl bonds. It is secreted by Clostridium histolyticum strains. For the first time we present evidence that both polypeptide chains of native clostripain are encoded by a single gene. DNA sequencing of two overlapping genomic DNA fragments revealed a single open reading frame (ORF) of 1581 nucleotides encoding a polypeptide of 526 amino acid residues. The ORF is preceded by canonical transcription signals and both chains of the clostripain heterodimer are completely represented by the deduced coding sequence. Most interestingly, the sequences coding for the light and the heavy chain are joined by a DNA stretch coding for a linker nonapeptide that is preceded by the C-terminal arginyl residue of the light chain and also ends with an arginyl residue. Heterologous expression of the gene in Escherichia coli yielded an enzyme capable of hydrolyzing the clostripain substrates N alpha-benzoyl-L-arginine ethyl ester (BAEE) and N-carbobenzoxy-L-arginine p-nitroanilide (Z-Arg-pNA).

Molecular probes for the detection of Kluyveromyces marxianus chromosomal DNA in electrophoretic karyotypes of intergeneric protoplast fusion products.

Random genomic DNA fragments from Kluyveromyces marxianus were cloned in order to identify chromosomal bands in pulsed field electrophoresis patterns of intergneric hybrid strains which were obtained by protoplast fusion. Molecular hybridization data indicated that the K. marxianus parental strain might be triploid, and it showed strong chromosome length polymorphism. We analyzed the karyotype of two Saccharomyces cerevisiae/K. marxianus hybrid strains (St. 1.St.46) with our DNA probes and with a Ty1 specific probe. We found indications for recombinational events which lead to the formation of hybrid chromosomal DNA molecules.

Characterization of yeasts with high L[+]-lactic acid production: lactic acid specific soft-agar overlay (LASSO) and TAFE-patterns.

Only few yeast strains are known for the high level production of L[+]-lactate. We report indications for the conspecifity of Kluyveromyces thermotolerans (formerly Saccharomyces veronae) strain CBS 4728 with Stamm 42 (formerly Saccharomyces pretoriensis, RADLER 1984). We suggest that Stamm 42 has little, if any relationship to Saccharomyces cerevisiae. Furthermore, we have optimized the method of Subden et al. (1982) for the detection of lactate producing microorganisms. Using this method in a screening with 100 yeast strains of our institute collection, we could not find additional strains with high L[+]-lactate production. This method may provide a useful tool for the molecular cloning of the unique yeast L[+]-LDH1) gene (s).